NC State
BioResources
  • Editorialpp 4490-4494Okpala, C. O. R. (2017). "Reflecting in the woods: Can it help to enhance the formulation of (our) research questions?" BioRes. 12(3), 4490-4494.AbstractArticlePDF
    Nowadays, reflecting and reflective practice are being incorporated into undergraduate and postgraduate learning across disciplines, and thus, both can be seen as prerequisite(s) to achieving effective research activity. On the other hand, trees represent organisms characterized by a perennial lifestyle to produce a majority of terrestrial biomass. Trees, when put together as a group, take on the identity as “the woods”, which can be seen in many parts of the globe. In science, the choice and use of research questions has been considered as very useful in the definition, collection and reporting of (relevant) information. But, can reflecting in the woods enhance the formulation of (our) research questions? In this editorial, an attempt is made to respond to this question, to show that the woods has promising potential to provide a positive atmosphere for effective reflective activity for any (scientific) researcher.
  • Editorialpp 4495-4496Lenahan, O. M. (2017). "Book review: Fabriano: City of Medieval and Renaissance Papermaking – The first 500 years," BioRes. 12(3), 4495-4496.AbstractArticlePDF

    The Italian town of Fabriano is known for producing high-quality handmade paper – an industry that began in the 13th century and that has endured for eight centuries. How did the industry take hold in this Italian town and how did it endure for so long? Author Sylvia Rodgers Albro tells this story in her new book, Fabriano: City of Medieval and Renaissance Papermaking. Readers who appreciate history and engineering will enjoy Albro’s narrative, wonderful photography, and diagrams as they bring to life the art, science, and social history of papermaking in Fabriano.

  • Editorialpp 4497-4499Hubbe, M. A. (2017). "Book review of an open textbook: Sustainability: A Comprehensive Foundation," BioRes. 12(3), 4497-4499.AbstractArticlePDF

    Paper was once the lightest, lowest-cost way to make information widely available in a form suitable for study and self-improvement. But paper-based textbooks, in the modern era, tend to be heavy and they can also strain the budgets of typical students. Given the fact that you are now reading an open-access journal, you may understand why many faculty members would possibly want to use an open-access textbook for some of their courses. This editorial considers one such course, and the assessment is generally favorable. But in addition to the classroom, a good open textbook may be regarded as a suitable foundation for one’s research. By citing an open textbook in the introduction to your research article, you can provide your readers with the option of gaining enough background to better appreciate your latest research findings.

  • Researchpp 4500-4514Li, T., Li, G., Lu, Q., Zhou, J., Li, M., Zhang, S., and Li, J. (2017). "Characterization of Tectona grandis extractives by GC-MS and IR and their infusion into rubberwood to modify dimensional stability," BioRes. 12(3), 4500-4514.AbstractPDF
    Teak (Tectona grandis) has been popularly known in the wood industry as a precious material due to its natural dimensional stability. To explore the main components affecting the dimensional stability of teak wood, the teak wood samples were extracted with different polar solvents, and the extractives were impregnated into rubberwood specimens to determine their effect on the dimensional stability of the modified rubberwood. The results showed that the methanol extractives of the teak wood exhibited the most significant effect on the dimensional stability of the rubberwood. The extractives were characterized by infrared (IR) and gas chromatograph/ mass spectrum (GC/MS). The GC/MS results showed that the methanol extractives primarily contained 9,10-anthracenedione, 1,1-dimethyl-3,4-bis(1-methylethenyl), and alcohol compounds. It was speculated that the alcohol compounds in the methanol extractives reacted with polar hydroxyl groups in the cell wall, which resulted in a decrease in the size of the site combined with bound water. Moreover, the hydrophobic hydrocarbon compound was impregnated into rubberwood to form a thin layer of protective film in the cells into which the water could not enter under 20 °C and 80% RH.
  • Researchpp 4515-4526Yamada, H., Miyafuji, H., Ohno, H., and Yamada, T. (2017). "Rapid and complete dissolution of softwood biomass in tetra-n-butylphosphonium hydroxide with hydrogen peroxide," BioRes. 12(3), 4515-4526.AbstractArticlePDF

    The wood dissolution properties of tetra-n-butylphosphonium hydroxide ([P4,4,4,4]OH) were investigated. Cedar wood meal was treated with several concentrations of aqueous (aq.) [P4,4,4,4]OH with hydrogen peroxide (H2O2) in a glass tube at 121 °C. The solution of 60% aq. [P4,4,4,4]OH with H2O2 at 121 °C showed the best dissolution capability for woody biomass with a high dissolution rate of 0.152 g min-1. Under this condition, 98.5% of the woody biomass, including both lignin and holocellulose, was dissolved after 3 h of treatment. The molecular weight distribution of lignin in the soluble fraction of the [P4,4,4,4]OH mixtures was determined via size exclusion chromatography, and its weight-average molecular weight decreased from approximately 7500 g/mole after 0.5 h to 2 h of treatment to 5700 g/mole after 3 h and 2500 g/mole after 5 h of treatment. Lower molecular weight components were determined by high-performance liquid chromatography, and vanillin and vanillic acid were identified. The dissolved cellulose was precipitated, and its polymerization degree decreased significantly after 0.5 h of treatment compared to that of the original cellulose.

  • Researchpp 4527-4546Hassan, N., Hamid, N. H., Jawaid, M., Tahir, P. M., and Ujang, S. (2017). "Decay resistance of acetic, propionic, and butyric anhydrides modified rubberwood against brown rot (Coniophora puteana)," BioRes. 12(3), 4527-4546.AbstractArticlePDF
    Rubber trees were cut to the dimensions 25 mm x 140 mm x 1000 mm (R x T x L) and kiln-dried (10% to 12% moisture content, MC). The specimens (20 mm x 20 mm x 5 mm) (R x T x L) were prepared, and a Soxhlet extraction with toluene/methanol/acetone (4:1:1 by volume) was performed for 8 h. The specimens were oven-dried (103 °C for 24 h) and cooled (gel silica). Then, vacuum impregnation was conducted, and reactions with acetic, propionic, and butyric anhydrides took place for 0.25 h, 1 h, 4 h, 8 h, 10 h, 15 h, 24 h, 30 h, 36 h, and 48 h at 120 °C. The chemical bonding was confirmed by Fourier transform infrared (FTIR) analysis. The specimens were leached in deionized water and exposed to brown rot (Coniophora puteana) in an incubation room at 22 °C for 16 weeks. The fastest reaction was with butyric anhydride, then propionic and acetic anhydrides. The lowest weight loss occurred with acetic anhydride after being decayed by C. puteana at 14.0% weight percent gain (WPG). All of the modified rubberwoods (acetic, propionic, and butyric anhydrides) at the maximum WPG were classified as durability class 1. The scanning electron microscopy (SEM) observation confirmed that the hyphae penetrated the cells in both the untreated and anhydride modified rubberwood.
  • Researchpp 4547-4566Steffen, F., Janzon, R., Wenig, F., and Saake, B. (2017). "Valorization of waste streams from deinked pulp mills through anaerobic digestion of deinking sludge," BioRes. 12(3), 4547-4566.AbstractArticlePDF

    Based on the results of this study, a total energy amount of 3,111 TJ/year can be produced from the anaerobic digestion of deinking sludge (DS) arising from German deinked pulp mills, which can then be used to replace up to 5% of the total energy demand for those mills. The DS examined was generated by flotation deinking at the laboratory scale from selected mixes of paper for recycling (PfR). The results from the batch fermentation tests indicated a strong dependence of the methane potential of the DS on the carbohydrates and lignin contents, which in turn are linked to the original PfR quality. The highest methane yield was observed for DS100 (25.8% carbohydrates; 5.1% lignin) with 280.4 mL/g of volatile solids (VS) added, while DS70 (14.2% carbohydrates; 24.9% lignin) showed the lowest methane yield, with 122.1 mL/gVS. All of the DS samples showed high methane production rates, in the range between 59.4 (DS70) and 118.6 mL/gVS d-1 (DS100), and kinetic constants of 0.66 to 0.79 d-1. Additionally, no distinguishable lag phases were observed, which strongly indicates the rapid biodegradation of the DS.

  • Researchpp 4567-4593Jones, B. W., Venditti, R., Park, S., and Jameel, H. (2017). "Optimization of pilot scale mechanical disk refining for improvements in enzymatic digestibility of pretreated hardwood lignocellulosics," BioRes. 12(3), 4567-4593.AbstractPDF
    Mechanical refining has potential application for overcoming lignocellulosic biomass recalcitrance to enzyme hydrolysis and improving biomass digestibility. This study highlighted the ability for a pilot scale disc refiner to improve the total carbohydrate conversion to sugars from 39% (unrefined hardwood sodium carbonate biomass) to 90% (0.13 mm gap, 20% consistency, ambient temperature) by optimizing the refining variables. The different biomass properties that changed with refining indicated the expected increase in sugar conversion. Controlling the refining parameters to narrower gaps and higher consistencies increased the resulting refined biomass hydrolysis. Positive correlations that increases in net specific energy (NSE) input and refining intensity (SEL) improved the enzymatic hydrolysis. In some severe cases, over-refining occurred when smaller gaps, higher consistencies, and more energy input reached a point of diminished return. The energy input in these scenarios, however, was much greater than realistically feasible for industrial application. Although well-established in the pulp and paper industry, gaps in understanding the fundamentals of refining remain. The observations and results herein provide the justification and opportunity for further mechanical refining optimization to maximize and adapt the mechanical refining technology for maximum efficiency within the process of biochemical conversion to sugar.
  • Researchpp 4594-4605Ahmad Yahaya, A. N., Hossain, M. S., and Edyvean, R. (2017). "Analysis of phenolic compounds in empty fruit bunches in oyster mushroom cultivation and in vermicompositing," BioRes. 12(3), 4594-4605.AbstractArticlePDF

    Analyses of total phenolic compounds were carried out for oil palm empty fruit bunches (EFBs) vermicomposting in oyster mushrooms cultivation. The oyster mushrooms (Pleurotus sajor-caju) were cultivated according to the large-scale vermicomposting trial (LSVT) methods. Both oyster mushrooms cultivation and vermicomposting of EFB with earthworms enhanced the lignin degradation of EFB. Analysis of total phenolic compounds EFB vermicomposting treated with earthworms showed a decrease in total phenolics concentration from 31.1 GAE/100g extract (raw EFB) to 5.66 g GAE/100g extract (after oyster mushroom cultivation) and to less than 1.5 g GAE/100g extract at the end of vermicomposting. Gas chromatography–mass spectrometry (GC-MS) analysis of the mushroom fruiting body, spent mushrooms, and vermicompost showed no trace of phenolphenol, pyrocatechol, 4-hydrobenzoic acid, or antioxidant and flavonoid phenolics, e.g., phenol, 3,4-dimethoxy-, vanillic acid, and cinnamic acid. This indicates that the mushroom fruiting body is fit for human consumption and the final vermicompost is a useful agricultural product without the detrimental effects of spreading phenolics-loaded EFBs on the land.

  • Researchpp 4606-4626Myronycheva, O., Bandura, I., Bisko, N., Gryganskyi, A. P., and Karlsson, O. (2017). "Assessment of the growth and fruiting of 19 oyster mushroom strains for indoor cultivation on lignocellulosic wastes," BioRes. 12(3), 4606-4626.AbstractPDF
    Twelve Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm and six Pleurotus pulmonarius (Fr.) Quél. strains were characterized from the National Culture Collection of Mushrooms, Institute of Botany Kholodny, National Academy of Science, Kyiv, Ukraine (IBK). The strains were grown under commercial conditions on a mixture of wheat straw and sunflower shells under both winter and summer temperatures typical for those climatic conditions. The strains were divided into three groups according to their growing patterns. Important characteristics were compared with a commercial analogue, HK-35, such as vegetative growth, generative growth, and biological efficiency (1.9- to 3.1-fold), and were recorded for strains 2251, 2292, 2316, 2319, and 2320 of P. ostreatus and 2314 of P. pulmonarius. Strains 2251, 2292, 2301, 2321 and 2323 were the most suitable for commercial production, while strains 2319 and 2320 could satisfy processing industry requirements with their high biological efficiency. Strains 2287 and 2317 produced high-quality fruit bodies but probably required a higher temperature for cultivation. Strain 2318 might be attractive for some consumers due to its unique and unusual fruit body shape. Strain 2314 was the most promising for summer cultivation, while strain 537 produced the highest quality fruit bodies.
  • Researchpp 4627-4638Wang, M., Zhang, Y., Yan, S., Yi, B., Niu, W., and Yuan, Q. (2017). "Enhanced biogas yield of Chinese herbal medicine extraction residue by hydrothermal pretreatment," BioRes. 12(3), 4627-4638.AbstractArticlePDF

    Chinese herbal medicine extraction residue (CHER) is a special organic waste produced in China. Because of the high content of lignocelluloses, CHER have a weak bioconversion efficiency for bio-products production. This study investigates the effect of a hydrothermal pretreatment (HTP, 140 to 220 °C, 15 min) on the organic matter solubilisation, biochemical methane potential, and methanation kinetics of CHER during anaerobic digestion (AD). The AD test was conducted with 5 g/L total solid at 35 °C for 30 d. The results showed that the HTP clearly improved the solubilisation of CHER, and the obtained soluble COD (%) reached over 30% (only 4.5% in untreated). Acetic acid, xylose, and glucose were found to be the main products in the hydrolysate. The methane yield and methanation speed of the treated CHER were also enhanced. The highest methane yield of 306 mL/g volatile solid was achieved at a HTP temperature of 180 °C, while the untreated control was only 175 mL/g VS. Moreover, a carbonisation phenomenon was observed at HTP temperatures over 200 °C, which resulted in a loss of organic matter and methane yield.

  • Researchpp 4639-4651Shao, L., You, T., Wang, C., Yang, G., Xu, F., and Lucia, L. A. (2017). "Catalytic stepwise pyrolysis of technical lignin," BioRes. 12(3), 4639-4651.AbstractArticlePDF

    The stepwise pyrolysis of technical lignin with and without a catalyst was investigated by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Lignin was first pyrolyzed at 260 or 360 °C, and then the residue was subsequently pyrolyzed at 650 °C. It was found that stepwise pyrolysis of lignin concentrated the phenolic compounds in lignin-derived bio-oil. In a stepwise 260 to 650 °C process, the maximum total phenolic compounds were 86.2%. Among the phenolic compounds, guaiacol-type and phenol-type phenolic compounds were predominant. Further addition of a catalyst (HZSM-5) in the stepwise pyrolysis process enhanced control over the product distribution through conversion of phenolic compounds into aromatic hydrocarbon products. The aromatic hydrocarbons achieved the highest yield of 30.4% in the catalytic stepwise 260 to 650 °C process.

  • Researchpp 4652-4669Zhang, Y., Ma, Z., Zhang, Q., Wang, J., Ma, Q., Yang, Y., Luo, X., and Zhang, W. (2017). "Comparison of the physicochemical characteristics of bio-char pyrolyzed from moso bamboo and rice husk with different pyrolysis temperatures," BioRes. 12(3), 4652-4669.AbstractPDF
    Bio-char pyrolyzed from biomass waste has been notably applied in various industries due to its versatile physicochemical characteristics. This paper investigated the difference of the properties of the bio-char derived from moso bamboo and rice husk under different pyrolysis temperatures (200 °C to 800 °C). As the temperature increased, the bio-char yield for both bamboo bio-char (BC) and rice husk bio-char (RHC) decreased, while the carbon element content and fixed carbon, the value of higher heating value (HHV) and pH increased for both BC and RHC. At 800 °C, BC had a higher HHV of 32.78 MJ/kg than RHC of 19.22 MJ/kg, while RHC had a higher yield of char (42.99 wt.%) than BC (26.3 wt.%) because of the higher ash content (47.51 wt.%) in RHC. SiO2 was the dominant component in the ash of RHC, accounting for 86.26 wt.%. The surface area (SBET) of RHC (331.23 m2/g) was higher than BC (259.89 m2/g). However, the graphitization degree of BC was higher than RHC at the same temperature. The systematic study on the evolution of the basic properties of BC and RHC will provide a good reference for their high value-added application.
  • Researchpp 4670-4689Meekum, U., and Kingchang, P. (2017). "Compounding oil palm empty fruit bunch/cotton fiber hybrid reinforced poly(lactic acid) biocomposites aiming for high-temperature packaging applications," BioRes. 12(3), 4670-4689.AbstractPDF

    The manufacture of poly(lactic acid) (PLA) composites reinforced with both oil palm empty fruit bunch (EFB) and cotton fiber was investigated. The positive and significant effect of EFB on the heat distortion temperature (HDT) and flexural properties was determined by a 2k design of experiment study. Adding solid epoxy into the PLA matrix manifested inferior mechanical properties with no improvement to the HDT. The HDT and mechanical properties of the biocomposites were further improved by using an EFB/cotton hybridized system. The PLA/hybridized EFB/cotton biocomposites showed biodegradability and an HDT higher than 100 °C. However, the flowability of the material was retarded at high cotton fractions. Finally, adding talc filler into the biocomposites improved the flowability of the hybridized biocomposite systems, especially at low fiber and high talc contents. Nevertheless, inferior mechanical properties of the biocomposites were found for high talc and low fibers’ contents.

  • Researchpp 4690-4706Xie, L., He, G., Wang, X., Gustafsson, P. J., Crocetti, R., Chen, L., Li, L., and Xie, W. (2017). "Shear capacity of stud-groove connector in glulam-concrete composite structure," BioRes. 12(3), 4690-4706.AbstractArticlePDF

    A timber-concrete composite structure (TCC) is economically and environmentally friendly. One of the key design points of this kind of structure is to ensure the reliability of the shear connectors. The objective of this paper is to study the mechanical property of stud-groove-type connectors and to provide shear capacity equations for stud-groove connectors in timber-concrete composite structures. Based on the Johansen Yield Theory (European Yield Model), some mechanical models and capacity equations for stud-groove-type connectors in timber-concrete structures were studied. Push-out specimens with different parameters (stud diameter, stud length, groove width, and groove depth) were tested to obtain the shear capacity and slip modulus. The experimental strengths were used to validate equations given in the paper. The shear capacity and slip modulus of stud-groove-type connectors was in direct proportion to the diameter of studs and the dimension of the groove. Comparison between the theoretical and the experimental shear strength results showed reasonable agreement. The highlight of this study on shear capacity equations could significantly reduce the push-out tests before investigating the other properties of TCC.

  • Researchpp 4707-4721Shi, S., Zhou, X., Chen, W., Wang, X., Nguyen, T., and Chen, M. (2017). "Thermal and kinetic behaviors of fallen leaves and waste tires using thermogravimetric analysis," BioRes. 12(3), 4707-4721.AbstractArticlePDF
    Thermal decomposition characteristics and kinetic parameters of fallen leaves (FLs), waste tires (WTs), and their blends (1:1 weight ratio) were investigated. Pyrolysis experiments were conducted with four different heating rates of 5 °C/min, 10 °C/min, 20 °C/min, and 40 °C/min from 35 °C to 800 °C in a nitrogen atmosphere using a thermogravimetric analysis (TGA). The thermogravimetry/derivative thermogravimetry (TG/DTG) curves indicated that the three samples were mainly degraded in a wide temperature range of 350 °C to 450 °C, and that a greater weight loss rate corresponded to a higher heating rate. An elemental analysis demonstrated that FLs/WTs blends embraced a maximum calorific value that reached 25.24 MJ/kg. Two model-free methods, iso-conversional Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) were applied on the TGA data of samples to calculate the activation energies. The results showed that the average activation energies of the same feedstock based on KAS and FWO methods were approximately the same, with the highest error within 1.6%. Then, the activation energies obtained were introduced in the Coats/Redfern (CR) model-fitting method to derive the pre-exponential factors, based on first order rate of reaction.
  • Researchpp 4722-4736Ma, Y., Wang, C., and Chu, F. (2017). "Effects of fiber surface treatments on the properties of wood fiber-phenolic foam composites," BioRes. 12(3), 4722-4736.AbstractArticlePDF

    Wood fibers were modified with alkaline solution and silane coupling agent to study changes on the fiber surface and the influence of these treatments on the mechanical properties, flame resistance, thermal conductivity, and microstructure of wood fiber-phenolic foam composites. Test results indicated that the lignin, waxes, hemicelluloses, and other impurities from the fiber surface were partially dissolved and removed. The mechanical properties of treated wood fiber-phenolic foam composites increased dramatically, the cellular pore distribution was more regular, the size of bubble cells was smaller and more uniform, and the thermal conductivity was reduced, and, in particular, the fragility of treated wood fiber-phenolic foam composites decreased. However, with increasing wood fiber content, the mechanical properties and limited oxygen index (LOI) of composite foam decreased. By comprehensive analysis, it was shown that the interfacial compatibility between the fibers and phenolic resin was improved. Nevertheless, the amount of wood used could not be too high, and the optimum amount was approximately 5%.

  • Researchpp 4737-4753Liu, H., Zhu, J. Q., Li, X., Li, H. Z., Qin, L., Li, H., Wang, X., Bai, X., Li, W. C., Li, B. Z., and Yuan, Y. J. (2017). "Hybridization improves inhibitor tolerance of xylose-fermenting Saccharomyces cerevisiae," BioRes. 12(3), 4737-4753.AbstractPDF

    Although some engineered S. cerevisiae strains exhibit good xylose utilization ability, the lack of tolerance to inhibitors generated in biomass pretreatment limits the application of such strains in the production of bioethanol from lignocellulosic biomass. By applying a sexual mating method, inhibitor tolerance was developed in xylose-utilizing strains. The final ethanol concentrations in simultaneous scarification and co-fermentation (SScF) process at 38 °C with hybrid strains were 50% higher than the SScF process with the xylose-fermenting parent strain. The strain viability of the hybrid strain E7-12 at 24 h was 282 times higher than the parent strain in the SScF process at 25% solid loading. Due to the improved sugar utilization, the final ethanol concentration reached 69.7 g/L (E7-11) and 70.0 g/L (E7-12), which were 25.3 g/L and 25.6 g/L higher than that of SScF with the xylose-fermenting strain, respectively.

  • Researchpp 4754-4775Young, T. M., Han, L. D., Perdue, J. H., Hargrove, S. R., Guess, F. M., Huang, X., Chen, C. H. (2017). "Impact of trucking network flow on preferred biorefinery locations in the southern United States," BioRes. 12(3), 4754-4775.AbstractPDF

    The impact of the trucking transportation network flow was modeled for the southern United States. The study addresses a gap in existing research by applying a Bayesian logistic regression and Geographic Information System (GIS) geospatial analysis to predict biorefinery site locations. A one-way trucking cost assuming a 128.8 km (80-mile) haul distance was estimated by the Biomass Site Assessment model. The “median family income,” “timberland annual growth-to-removal ratio,” and “transportation delays” were significant in determining mill location. Transportation delays that directly impacted the costs of trucking are presented. A logistic model with Bayesian inference was used to identify preferred site locations, and locations not preferential for a mill location. The model predicted that higher probability locations for smaller biomass mills (feedstock capacity, the size of sawmills) were in southern Alabama, southern Georgia, southeast Mississippi, southern Virginia, western Louisiana, western Arkansas, and eastern Texas. The higher probability locations for large capacity mills (feedstock capacity, the size for pulp and paper mills) were in southeastern Alabama, southern Georgia, central North Carolina, and the Mississippi Delta regions.

  • Researchpp 4776-4794Guo, H., Lin, C., Wang, S., Jiang, D., Zheng, B., Liu, Y., and Qin, W. (2017). "Characterization of a novel laccase-producing Bacillus sp. A4 and its application in Miscanthus degradation," BioRes. 12(3), 4776-4794.AbstractPDF
    Bacillus sp. A4 exhibiting laccase production was isolated from forest soil. Its laccase secreted into a LB medium exhibited a maximum activity of 3.9 U mg-1 protein at the optimal temperature (37 °C) and pH (6.0). The purified laccase of Bacillus sp. A4 demonstrated a low molecular mass of 33 kDa, and its optimal temperature and pH were 40 °C and 4.6, respectively, when using ABTS as a substrate. The activity of the purified laccase was significantly increased in the presence of Cu2+, methanol, and ethanol, but it was totally inhibited by L-cysteine. The laccase production of this strain was markedly stimulated when the strain was incubated with 0.5% different lignocellulosic biomasses. The highest activity of laccase (22.6 U mg-1 protein) was obtained in using algal biomass. This new strain efficiently decreased the lignin content of lignocellulose biomasses after 9 d of incubation at 37 °C, especially lignin from grasses. Further analysis showed that, compared to that of all tested biomasses, the new strain was a more efficient decomposer of the lignin of Miscanthus, which exhibited much more lignin loss and cell wall structure destruction in a short span of time. Therefore, the potential use of this strain could be advantageous for using lignin in Miscanthus for industrial processes.
  • Researchpp 4795-4809Pan, X., Zhuang, X. W., and Chen, S. W. (2017). "Rice husk char/poly-(acrylic acid-co-acrylamide) superabsorbent hydrogels: Preparation, characterization, and swelling behaviors," BioRes. 12(3), 4795-4809.AbstractArticlePDF

    A series of novel rice husk char/poly-(acrylic acid(AA)-co-acrylamide(AM)) superabsorbent hydrogels were synthesized by graft copolymerization. The effects of the rice husk char (RHC) loading on their miscibility, shapes, and chemical structures were studied, and their swelling behaviors, kinetics, and pH response were evaluated. During the preparation, RHC reacted with acrylic acid. The RHC at lower loads (< mass ratios of RHC and AA of 1%) was scattered well within the polymer matrix, but an excessive load might result in the formation of large agglomerates. The swelling capacity and swelling rate of the hydrogels first were both increased with the rising RHC loading to 1% and then declined with further RHC loading. The superabsorbent hydrogel containing 1% RHC had the highest water absorbency (869 g/g in deionized water and 97 g/g in 0.9% NaCl solution).

  • Researchpp 4810-4829Ye, H., Zhang, Y., and Yu, Z. (2017). "Effect of desulfonation of lignosulfonate on the properties of poly(lactic acid)/lignin composites," BioRes. 12(3), 4810-4829.AbstractArticlePDF

    To utilize the lignin generated by the paper industry and reduce the cost of poly(lactic acid) (PLA), PLA/lignin composites were prepared from PLA and different ratios of lignosulfonate (LS) or desulfonated lignosulfonate (DLS) particles using a casting method. The physicochemical properties of the lignins were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), gel permeation-high performance liquid chromatography (GPC), and elementary analysis. The results indicate that the sulfur content of the original LS was successfully reduced to half by desulfonation to produce DLS, which was found to have a higher thermal stability and a lower average molecular weight than LS. Additionally, the thermal stability, crystallization, compatibility, mechanical, hydrophobicity, and optical properties of the PLA/lignin composites were also meticulously evaluated. Comparison of the PLA/DLS and PLA/LS composites revealed that the incorporation of DLS into PLA improved compatibility, thermal stability (T5% and Tmax), and hydrophobicity, while the mechanical properties remained almost unchanged. In addition, both PLA/DLS and PLA/LS exhibited UV light absorption capacity. Finally, the low-rate addition of both LS (10%) and DLS (5%) accelerated the crystallization of PLA, but crystallization was delayed with higher lignin content.

  • Researchpp 4830-4853Wang, Y., Chen, M., Yang, J., Liu, S., Yang, Z., Wang, J., and Liang, T. (2017). "Hydrogen production from steam reforming of acetic acid over Ni-Fe/Palygorskite modified with cerium," BioRes. 12(3), 4830-4853.AbstractArticlePDF

    The steam reforming of acetic acid (SRA) was carried out in a fixed-bed tubular reactor with Ni-Fe/ceria-palygorskite (CPG) catalysts. The as-prepared catalysts were analyzed by N2 adsorption-desorption, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), H2 temperature programmed reduction (H2-TPR), and X-ray diffraction (XRD). The results of H2-TPR and XRD showed that the addition of CeO2 increased the hydrogen consumption of catalysts and the interaction force between active component (Ni-Fe alloy) and carrier. Moreover, the Ni-Fe alloys were successfully synthesized in the Ni-Fe/CPG catalysts and their crystallite sizes were decreased by adding CeO2. In addition, these catalysts were employed to SRA at 600 °C, GHSV = 14427 h-1 and different molar ratio of S/C. The experimental results revealed that the Ni-Fe/C0.4PG0.6 catalyst can achieve the highest yield of H2 (87%) and HOAc conversion (95%), as well as the highest stability during the process of steam SRA. Additionally, the spent catalysts were characterized by XRD, SEM, and thermogravimetric analysis (TGA). The results showed that the addition of CeO2 enhanced the stability and activity of Ni-Fe/palygorskite catalyst and reduced the coke deposition rate on the catalyst surface.

  • Researchpp 4854-4866Hu, G., Fu, S., Chu, F., and Lin, M. (2017). "Relationship between paper whiteness and color reproduction in inkjet printing," BioRes. 12(3), 4854-4866.AbstractArticlePDF

    Paper is widely used as a substrate for inkjet printing, where the paper feature heavily impacts the print quality, especially the color reproduction. The unprinted area on paper is visible and applied as a background reflectance for the toner layer. Hence, it is worthwhile to understand the effects of paper whiteness on print color reproduction. In this study, the tested papers were treated with different dyes, which resulted in the change of the paper’s optical properties, but not surface roughness. The print density was impacted by the paper whiteness and ISO brightness. The effect of the paper whiteness on the print density is a stronger linear correlation compared to the ISO brightness. Paper whiteness has a positive correlation with the ISO brightness. The print colorimetric values (lightness and chroma values) increased with increasing paper whiteness up to a certain level, after which the paper whiteness did not have a noticeable impact on its print lightness and chroma values. The print color (a* and b* values) was affected by its corresponding paper color.

  • Researchpp 4867-4880Shao, S., Wu, C., and Chen, K. (2017). "Refining, dewatering,  and paper properties of soda-anthraquinone (Soda/AQ) pulp from rice straw," BioRes. 12(3), 4867-4880.AbstractArticlePDF

    The dynamic drainage, zeta potential, cationic demand, fiber morphology, ash content, and silica content of rice straw soda-anthraquinone (soda/AQ) pulps were measured to study the effects of a mechanical treatment on the drainage performance. The physical properties of handsheets prepared from each beaten sample were also analyzed. It was indicated that pulp fibers played an important role in increasing the beating degree in comparison with non-fibrous cells during refining. The dynamic drainage curve could be divided into three different stages in terms of the drainage rate, and the difference between the pulps screened-out non-fibrous cells (Pnof), and unremoved non-fibrous cells (Pf) decreased with refining. Due to the absence of a large quantity of non-fibrous cells, as the beating proceeded, the straw pulp presented an ever-increasing tendency in terms of kink index and curl index. Also, cationic demands of pulps increased linearly and the zeta potential of the fibers decreased gradually with beating. Rice straw was found to be favorable for papermaking, helping to compensate for an acute shortage of wood in China.

  • Researchpp 4881-4896Vančo, M., Jamberová, Z., Barcík, S., Gaff, M., Čekovská, H., and Kaplan, L. (2017). "The effect of selected technical, technological, and material factors on the size of juvenile poplar wood chips generated during face milling," BioRes. 12(3), 4881-4896.AbstractArticlePDF

     

    The effects of technical, technological, and material factors affecting the size of juvenile poplar wood chips were evaluated. Each analysis was performed on two species of poplar, namely natural poplar Populus tremula L. and plantation poplar clones Populus euramericana Serotina, and on juvenile and mature wood within each poplar species. A cutter with angular geometry was selected for the face milling: b = 55° (angle of cutting wedge), g = 15° (rake angle). The cutting conditions were a feed rate of vf = 2.5 and 15 m·min-1, cutting speed of vc = 30 m·s-1, 45 m·s-1, and 60 m·s-1, and the depth of cut ap = 1 mm. An image analysis of the size of the largest and smallest fraction was performed. Most of the chips generated during the face milling of poplar wood were classified as flat grain wood. A small percentage of the generated chips could be included in the group of rod-shaped fibrous bulk particles with a considerable extension in one direction (smaller fractions generated at a feed rate of 2.5 m·min-1, and at the finest fractions- dust generated in all of the combinations of technical and technological parameters).

  • Researchpp 4897-4911Li, J., Ma, Q., Shao, H., Zhou, X., Xia, H., and Xie, J. (2017). "Biosynthesis, characterization, and antibacterial activity of silver nanoparticles produced from rice straw biomass," BioRes. 12(3), 4897-4911.AbstractArticlePDF

    Silver nanoparticles (AgNPs) were synthesized from AgNO3 using rice straw biomass as the reducing agent at room temperature via light irradiation. Full wavelength scanning with UV/Vis spectrophotometer was used to study the effect of light intensity, reaction time, and concentrations of rice straw biomass and AgNO3 during AgNPs synthesis. Surface plasmon resonance (SPR) showed that the peak wavelength of synthesized silver nanoparticles arose at 425 nm, the optimal light intensity observed was 60,000 lx, and the optimal reaction time was 140 min. The optimum concentrations of the rice straw biomass and AgNO3 used were 4 mg/mL and 2 mM, respectively. The AgNPs were characterized by X-ray diffraction (XRD) analysis. The zeta potential of AgNPs reached -21.2 mV. In addition, the AgNPs synthesized by rice straw biomass revealed antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphyloccus aureus. The inhibition rate reached about 97.17 ± 2.01% when the concentration of AgNPs solution used was 8 μg/mL. In the detection of antimicrobial effect of AgNPs and antibiotics, the antibacterial activity was found to be superior to that of antibiotics alone.

  • Researchpp 4912-4925Cui, L., Chen, T., Quan, G., Xiao, B., Ma, Y., Pan, M., Liu, Y., Liu, B., Yin, C., Yan, J., Han, X., Ding, C., Cui, J., Bian, M., and Hussain, Q. (2017). "Renewable material-derived biochars for the efficient removal of 2,4-dichlorophen from aqueous solution: Adsorption/desorption mechanism," BioRes. 12(3), 4912-4925.AbstractArticlePDF

    This study investigated the efficiency of peanut hull (PBC), bush branch (BBC), Spartina alterniflora (SBC), and rape straw (RBC) in removing 2,4-dichlorophen (2,4-DCP) from an aqueous solution. The 2,4-DCP removal efficiency of the four kinds of biochars (BCs) increased in the order BBC > PBC > SBC > RBC. The adsorption process was affected by the pH, contact time, temperature, BC’s particle size, and dosage. Based on the results of Fourier transform infrared spectrometry (FTIR) and scanning electron microscope (SEM), the adsorption mechanism of 2,4-DCP was associated with the functional groups and the microtissue and structure of BCs. Furthermore, the organic components of the BCs played an essential role during the adsorption process of the 2,4-DCP. The remediation of organic pollutants by BCs is a complicated process that is characterized by the physical-chemical reaction between the two components (organic pollutants and BCs).

  • Researchpp 4926-4942Yuan, J., He, Y. Z., Guo, Z. W., Gao, H. F., Chen, F. B., Li, L. Z., Li, Y. Y., and Zhang, L. Y. (2017). "Utilization of sweet sorghum juice for efficient 2,3-butanediol production by Serratia marcescens H30," BioRes. 12(3), 4926-4942.AbstractArticlePDF

    Sweet sorghum juice (SSJ) is considered a good carbon source for biorefinery due to its low price and high fermentable-sugar content. In this study, 2,3-butanediol (2,3-BD) production from SSJ by Serratia marcescens H30 was investigated. First, the medium compositions including the contents of SSJ, nitrogen source, and mineral salts were optimized in conical flasks using a single factor and orthogonal design method. Under the optimal conditions, the 2,3-BD concentration reached up to 33.40 g/L. Then the optimized medium was used to perform fermentative experiments in a 5-L bioreactor. In batch experiments, the effects of various agitation speeds on 2,3-BD production were compared. Based on batch process results, an efficient two-stage fermentative control strategy was developed, where the agitation speed was maintained at 300 rpm in the first 12 h and subsequently switched to 200 rpm. About 43.32 g/L 2,3-BD was obtained by using this strategy. Finally, fed-batch fermentation was conducted through feeding the concentrated SSJ and a maximum 2,3-BD concentration of 109.44 g/L with the productivity of 1.40 g/L·h; a yield of 83.02% was achieved. The results showed that SSJ could be used as an economical substrate for efficient 2,3-BD production by S. marcescens H30.

  • Researchpp 4943-4957Palanti, S., Vignali, F., Elviri, L., Lucchetti, C., Mucchino, C., and Predieri, G. (2017). "Effect of amine functionalization and ageing on copper and boron leaching from wood preservatives grafted to siloxane networks," BioRes. 12(3), 4943-4957.AbstractArticlePDF
    The study evaluated copper, boron, and silicon release from wood samples treated with sol-gel formulations based on tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) functionalized with copper (II) chloride and boric acid, respectively. The adopted leaching procedure was Japanese protocol JIS K 1571 (2004). Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) and Electron Spray Ionization Mass Spectrometry (ESI-MS) were employed for analyzing the leached solutions. The obtained results highlighted the important role of the amine function that was derived from the APTES precursor, in anchoring both copper and boron through coordinative and ionic interactions, respectively. In fact, copper formulations with TEOS alone (without APTES) showed higher copper leaching. In contrast, the silicon leaching was decreased due to better siloxane reticulation performed by TEOS alone. In addition, ageing (two months) of the samples treated with APTES containing formulation TEOS/APTES/Cu 10:1:0.2 resulted in a reduction of copper leaching (from 27% in the fresh samples to 7% in the aged ones), which was attributable to increased efficiency of inorganic sol-gel polymerization. The TEOS/APTES/B 1:1:0.2 formulation gave a leaching value of 20%, which was lower in comparison with the values reported in previous literature.
  • Researchpp 4958-4971Liu, Z., Wang L., Zhang, Y., Li, Y., Li, Z., and Cai, H. (2017). "Cellulose-lignin and xylan-lignin interactions on the formation of lignin-derived phenols in pyrolysis oil," BioRes. 12(3), 4958-4971.AbstractArticlePDF

    To gain a better understanding of the effect of the interactions between two biomass components (cellulose-lignin and xylan-lignin) on lignin-derived phenolic products, two analysis methods are introduced. With 3:1, 2:1, and 1:1 ratios of cellulose and lignin, and xylan and lignin, the mixtures were subjected to fast pyrolysis, which was carried out in a fixed-bed tubular furnace at 450 to 600 °C. The phenolic content in the bio-oils was analyzed by gas chromatography-mass spectrometry. The product distributions showed that cellulose, xylan, and lignin were the main contributors to the mass of biomass bio-oil, gas, and char, respectively. The char yields decreased and the bio-oil and gas yields increased in the presences of cellulose and xylan. Comparative analyses of both the phenol content and peak area of the two methods suggest that in the case of cellulose and lignin co-pyrolysis, the formation of three kinds of phenolic products is promoted. The strength of this positive effect increased with increasing lignin content. However, the production of hydroxyphenols is promoted, while the productions of guaiacols and syringols are inhibited by the effect of xylan, which creates a different interaction between xylan and lignin.

  • Researchpp 4972-4985Ziaei-tabari, H., Khademieslam, H., Bazyar, B., Nourbakhsh, A., and Hemmasi, A. H. (2017). "Preparation of cellulose nanofibers reinforced polyether-b-amide nanocomposite," BioRes. 12(3), 4972-4985.AbstractArticlePDF

    A new kind of thermoplastic elastomer nanocomposite reinforced with cellulose nanofibers has been reported. The aim of this investigation was to study the interaction and dispersion of cellulose nanofibers into the Pebax matrix. These copolymers are considered as polyether-b-amide thermoplastic elastomers. They are from renewable resources, and their hydrophilic character allows them to interact with nanocellulose. The interaction and reinforcement effect of nanocellulose at 3 levels of nanocellulose, (1%, 3%, and 5%), were examined by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and other mechanical tests. The results achieved from these tests indicated appropriate effects of cellulose nanofibers for the strong interaction and close contact with the polyamide phase of the Pebax polymer via strong hydrogen bonding.

  • Researchpp 4986-5000Leng, W., Hunt, J. F., and Tajvidi, M. (2017). "Effects of density, cellulose nanofibrils addition ratio, pressing method, and particle size on the bending properties of wet-formed particleboard," BioRes. 12(3), 4986-5000.AbstractArticlePDF
    Wet-formed particleboard bonded with cellulose nanofibrils (CNF) was prepared in this work. The effects of density, CNF addition ratio, pressing method, and particle size on the bending strength were evaluated. The results showed that density had the most important effect on the modulus of elasticity (MOE), while the CNF addition ratio had the most important effect on the modulus of rupture (MOR). For panels with low density (< 640 kg/m3), the MOE and MOR did not change much with the configuration changes between particle size and pressing method. This was due to the synergistic effect of incomplete compression and poor bonding in the core area using a constant thickness (CT) pressing method, and lower face density and higher core density using a constant pressure (CP) pressing method. For panels with medium density (640 kg/m3 to 800 kg/m3), the combination of larger particles, higher CNF addition ratio, and CT pressing method contributed to the highest bending strength. Further increase to high density (> 800 kg/m3), the pressing method’s effect was more important, compared to panels with low and medium densities. With increased density and CNF addition ratio, panels were able to meet low-density and some medium-density standard MOE and MOR requirements.
  • Researchpp 5001-5016Guo, D., Liu, B., Tang, Y., Zhang, J., Xia, X., and Tong, S. (2017). "Catalytic depolymerization of alkali lignin in sub- and super-critical ethanol," BioRes. 12(3), 5001-5016.AbstractArticlePDF
    The effects of reaction parameters on catalytic depolymerization of alkali lignin in sub- and super-critical ethanol were investigated using a high pressure autoclave, and the liquid oil and solid char products were characterized. The experimental data indicated that Rh catalysis, controlling reaction conditions at ethanol critical temperature (240 ºC) and pressure (7.0 MPa), high ethanol/water ratios (100/0), and the medium reaction time (4 h) enhanced the depolymerization of alkali lignin to liquid oil and decreased the char formation. A gas chromatography/mass spectroscopy (GC/MS) analysis showed that the main compositions of liquid oils were phenols, esters, ketones, and acid compounds, and the supercritical state favored the formation of bio-phenols, but the subcritical state improved the generation of bio-esters. Scanning electron microscopy (SEM) and Fourier transform infrared spectrometer (FTIR) spectra analysis showed that the addition of the Raney/Ni and Rh/C catalysis could inhibit the re-fusion of alkali lignin micron-sized spheres in the supercritical ethanol, which led to an increase in the occurrence of the depolymerization reactions.
  • Researchpp 5017-5030Geffert, A., Vacek, O., Jankech, A., Geffertová, J., and Milichovský, M. (2017). "Swelling of cellulosic porous materials - mathematical description and verification," BioRes. 12(3), 5017-5030.AbstractArticlePDF

    The swelling of natural porous materials, including bleached pulp, as represented by mathematical descriptions, is influenced by a variety of different operating factors. The formerly used Generalised Hygroscopicity Model leads to either a disproportion between a model and a limit value of the sorption capacity or to noticeable deviation in the early swelling phase. Alternatively, the so-called Simple Bounded Growth model solely depends on the maximum sorption capacity, ignoring the physical properties that affect the fibre swelling rate. This research shows that the combination of the two models best describes the swelling process of bleached pulp – a rapid swelling phase and a slower swelling phase. The combined model was found to be useful in characterizing the well-known hornification process.

  • Researchpp 5031-5044Park, C. W., Han, S. Y., Namgung, H. W., Seo, P. N., Lee. S. Y., and Lee, S. H. (2017). "Preparation and characterization of cellulose nanofibrils with varying chemical compositions," BioRes. 12(3), 5031-5044.AbstractArticlePDF
    Cellulose nanofibrils (CNF) can be divided into lignocellulose nanofibrils (LCNF), holocellulose nanofibrils (HCNF), and pure cellulose nanofibrils (PCNF), dependent upon their chemical composition. The effect of the chemical composition on the defibrillation efficiency and the properties of the CNFs prepared by wet disk-milling was investigated using six different wood species. The defibrillation efficiency was improved when the lignin and hemicellulose was removed, and smaller fibers with diameters in the order of PCNF > HCNF > LCNF were produced. The average diameter of the hardwood LCNF was finer than that of the softwood LCNFs, but there was no noticeable difference in the diameters of the HCNF and the PCNF from the different wood species. The filtration time of CNF suspensions and the tensile properties of nanopaper sheets were longer and higher, respectively, in the order of HCNF > PCNF > LCNF from different wood species.
  • Researchpp 5045-5056Liu, X., Jiang, Y., Xie, Q., Nie, S., and Song, X. (2017). "Effect of alkali pectinase pretreatment on bagasse soda-anthraquinone pulp," BioRes. 12(3), 5045-5056.AbstractArticlePDF
    Pectinase pretreatment prior to bagasse soda-anthraquinone (AQ) pulping was conducted, and the effects of pectinase pretreatment on the pulp strength properties, energy consumption, and pulpability were evaluated in this study. Considering the pulp properties, the optimal conditions for the pectinase pretreatment were a pectinase dosage of 60 U/g (with respect to oven-dry bagasse) and 60-min treatment time. Compared with the control pulps obtained under the same treatment conditions with enzyme pretreatment (just without enzyme addition), the pretreated pulps attained a reduction in kappa number of 17.8% and an increase in total pulp yield of 15.8%. Moreover, higher breaking length, burst factor, and tear factor after soda-AQ pulping were found in the pectinase-pretreated samples, which suggests some improvements in pulp strength properties. With pectinase treatment, a 1% reduction in alkali charge and 20% decrease in pulping time were observed in subsequent pulping stages without affecting the pulp properties. Pectinase treatment prior to pulping seems to be a promising, economically feasible, and eco-friendly concept.
  • Researchpp 5057-5070Weng, J., Qiu, R., and Chen, L. (2017). "Composite paper sheet containing TiO2-diatomite for removing phenol in aqueous solution," BioRes. 12(3), 5057-5070.AbstractArticlePDF
    Composite paper sheet containing titanium dioxide and diatomite (TiDI) was prepared via a papermaking technique. The composite sheet was applied to remove phenol from aqueous solution. The composite sheet with a 2:1 mass ratio of cellulosic-fiber to TiDI removed phenol more effectively under UV irradiation than the composite paper sheet that utilized titanium dioxide (TiO2) alone. Composite paper sheets that contained TiDI with a TiO2/diatomite mass ratio of 1:2 removed phenol most effectively. The results showed that the TiDI composite paper could serve as a functional material to photodegrade phenol from aqueous solution under UV irradiation effectively.
  • Researchpp 5071-5085Jin, X. B., Jiang, Z. H., Wen, X. W., Zhang, R., and Qin, D. C. (2017). "Flame retardant properties of laminated bamboo lumber treated with monoammonium phosphate (MAP) and boric acid/borax (SBX) compounds," BioRes. 12(3), 5071-5085.AbstractPDF

    This study aimed to improve the flame-retardant properties of laminated bamboo lumber (LBL) using phosphorus-nitrogen-boron flame retardants (FRs). The combination of a 7:3 ratio of monoammonium phosphate (MAP) and boric acid/borax compounds (SBX), and 74.32 kg/m3 of FRs (10.3% weight gain), exhibited enhanced fireproofing performance for LBL materials. A commercial flame retardant (guanylurea phosphate) (GUP) was systematically studied as a comparison. A cone calorimeter and a thermal analyzer were used to characterize the combustion behavior and thermal stability, respectively. The flame retardants morphology in bamboo cell cavities was investigated using scanning electron microscopy (SEM) and an energy dispersive X-ray analysis (EDXA). The results showed that at a heat flux of 50 kW/m2, the heat release rate and the total heat release of LBL samples treated with MAP-SBX flame retardants decreased more considerably than that of the untreated samples. The use of MAP-SBX not only promoted carbonization of LBL greatly but also indicated a good performance of smoke and combustion suppression as well as for the GUP. Flame retardants were confirmed to penetrate into the cell cavities of the bamboo using SEM and EDXA.

  • Researchpp 5086-5101Meekum, U., and Kingchang, P. (2017). "Peroxide/silane crosslinked poly(lactic acid) hybrid biocomposite reinforced with empty fruit bunch and cotton fibers for hot-fill food packaging," BioRes. 12(3), 5086-5101.AbstractArticlePDF

    A biocomposite manufactured from peroxide/silane crosslinked poly(lactic acid) reinforced with hybridized empty fruit bunch (EFB) oil palm and cotton fibers was investigated. Optimization of dicumyl peroxide (DCP) and the vinyltrimethoxysilane (VTMS) crosslink system by using the 2k factorial design of experiment (DOE), with k = 2 was preliminary employed. There was no significant effect of the designed parameters, DCP(A) and VTMS(B), on the properties of the biocomposite. Concerning the environmental and economical aspects, the DPC and VTMS ratio was important. A crosslink agent content from 0.5 phr of DCP with 1 phr to 2 phr VTMS was recommended to manufacture a biocomposite with high heat distortion temperature (HDT) at above 100 °C and reasonable flow and mechanical properties. Also, the direct addition of the DCP/VTMS crosslink agent onto the PLA/rubber compound mixture and fed into a twin screw extruder for producing crosslinked PLA/EFB/cotton hybrid biocomposites were the optimized mixing methods. Shorter process line/time, ease of process steps, and reasonable engineering properties were justified. A HDT above 100 °C with a better toughness property of the biocomposite material was obtained. The PLA/PLA and PLA/ENR crosslinks via silane/moisture condensation during the sauna incubation was the prime explanation.

  • Researchpp 5102-5117Zhou, C., Dong, A., Wang, Q., Yu, Y., Fan, X., Cao, Y., and Li, T. (2017). "Effect of common metal ions and anions on laccase catalysis of guaiacol and lignocellulosic fiber," BioRes. 12(3), 5102-5117.AbstractArticlePDF

    The effects of 12 common metal ionic compounds on the laccase catalytic activity in reactions using guaiacol as the substrate was determined using spectrophotometry. Furthermore, the influence of several metal ionic compounds on the generation of reactive oxygen species (ROS) by oxidation of lignin in jute fiber under laccase catalysis was studied by electron paramagnetic resonance (EPR) spectroscopy using N-tert-butyl-alpha-phenylnitrone (PBN) as the spin-trapping agent. Common metal cations, such as K+, Na+, Mg2+, Ca2+, and Cu2+ and the anion SO42- had almost no effect on laccase activity during the initial stage of the catalytic reactions. High concentrations of the Mn2+ ion exhibited weak inhibition of laccase; Ag+ and NO3- showed a moderate inhibitory effect on laccase activity during the initial stage of the catalytic reactions. Fe2+ had no direct effect on the binding of laccase to its substrate, but strongly retarded the progress of the catalytic reaction by reducing the intermediate free radicals. The ions Cl-, Fe3+, and Ag+ exhibited either strong inhibitory effects on the catalysis of the substrate or a destructive effect on the structure of laccase itself. Furthermore, the results showed that an appropriate concentration of Cu2+ helped to promote the thermal stability of laccase during the enzymatic reaction. This study could help researchers to avoid the use of inhibitory exogenous metal ions and anions in the application of laccase and to maximize the value of laccase.

  • Researchpp 5118-5127Matthews, S., Toghyani, A. E., Eskelinen, H., Luostarinen, L., Kärki, T., and Varis, J. (2017). "Method for limiting waste in wood plastic composite post-production by means of press unit control parameters utilizing temperature-related dimensional changes," BioRes. 12(3), 5118-5127.AbstractArticlePDF

    Wood plastic composites are an interesting development in composite materials. They have gained wide market interest recently because of their sustainable material sources and beneficial material properties. Because thermosets or thermoplastics are involved in the composites, the material is temperature-dependent and susceptible to considerable dimensional changes with the variation of temperature. To minimize waste generation and enable reheated material post-processing, the distortion and displacement of the composite material has to be controlled precisely in different temperature ranges. This article studies ways to control this displacement and proposes a solution with an odometer and polynomial curve fit.

  • Researchpp 5128-5139Xu, M., Zhang, Q., Xing, L., and Pu, J. (2017). "Novel medium-density fibreboard produced by ultrasonic-assisted pulp with superhydrophobic and flame-resistant properties," BioRes. 12(3), 5128-5139.AbstractArticlePDF

    A novel medium-density fibreboard produced by an ultrasonic-assisted wheat straw pulp (UWP) was obtained without adhesives. It was then coated with a superhydrophobic sol solution integrated with an in vitro addition of two fire retardants (polyhedral methyl-silsesquioxane and ammonium polyphosphate) during the process of sol-gel reaction involving the two silane precursors tetraethyl orthosilicate (TEOS) and tridecafluorooctyltriethoxysilane (FAS). The coated UWP medium-density fibreboard (UPB) had good strength properties and possessed excellent hydrophobicity (water contact angle (WCA) above 150°), and flame-resistant properties (limiting oxygen index (LOI) improved by 5% compared with the original sample with a LOI of 18%). Meanwhile, the fibreboard also exhibited outstanding anti-permeability towards water (kept constant WCA for more than 1 h).

  • Researchpp 5140-5154Vančo, M., Mazán, A., Barcík, S., Rajko, L., Koleda, P., Vyhnáliková, Z., and Safin, R. R. (2017). "Impact of selected technological, technical, and material factors on the quality of machined surface at face milling of thermally modified pine wood," BioRes. 12(3), 5140-5154.AbstractArticlePDF

    The impact of technical and technological parameters on the quality of machining during milling of thermally modified pine wood (Pinus sylvestris L.) was studied. Experiments were conducted to evaluate the effects of tools (α = 30°, β = 45°, γ = 15°, 20°, and 30°), material (natural material, thermally treated at 160 °C, 180 °C, 210 °C, and 240 °C), and technological factors, such as cutting speed (20 m.min-1, 40 m.min-1, and 60 m.min-1) and feed rate (6 m.min-1, 10 m.min-1, and 15 m·min-1) on the quality of the machined surface (standard deviation of surface Ra). The roughness measurements were realized by a non-contact method using a laser. This paper aimed to highlight which one of the technological or tool factors had the greatest impact on the quality of the surface of heat-treated wood in face milling. The importance of the parameters impact on surface quality was in the following order: rake angle, feed rate, thermal treatment, and cutting speed.

  • Researchpp 5155-5173Malá, D., Sedliačiková, M., Kaščáková, A., Benčiková, D., Vavrová, K., and Bikár, M. (2017). "Green logistics in Slovak small and medium wood-processing enterprises," BioRes. 12(3), 5155-5173.AbstractArticlePDF

    Current approaches in logistics are focused on sustainable development of enterprises and society. Small and medium enterprises (SMEs), in this case wood-processing enterprises, can achieve this goal by implementing green logistics strategies in business practice. The main objective of this paper is to propose an algorithm for the implementation of green logistics activities in wood-processing SMEs, through a survey aimed at analyzing the accelerators and barriers to implementation in business practice. The research has been evaluated via methods of testing the statistical hypothesis (binomial test, Chi-squared, Friedman test, Wilcoxon test), methods of descriptive statistics, and data visualization. The survey found that one of the most significant determinants for implementing green logistics activities in a wood-processing enterprise is a decrease in cost. Based on the performed analysis, a model for the implementation of green logistics activities for wood-processing SMEs was proposed that includes appropriate activities that ensure the sustainable development of wood-processing SMEs in Slovakia.

  • Researchpp 5174-5195Cai, Q., Xu, J., Zhang, S., and Wang, S. (2017). "Aromatic hydrocarbon generation from a simulated bio-oil fraction by dual-stage hydrogenation-cracking: Hydrogen supply and transfer behaviors," BioRes. 12(3), 5174-5195.AbstractArticlePDF

    The improvement of the hydrogen-poor composition of bio-oil is important for its cracking to produce aromatic hydrocarbons. In this work, a mild hydrogenation pre-treatment and methanol cocracking were combined to implement proper hydrogen supplementation for cracking. Acetic acid (HAc), hydroxypropanone (HPO), and cyclopentanone (CPO) were selected as model compounds and mixed to prepare a simulated distilled fraction (SDF) of bio-oil. The hydrogen supply and transfer behaviours in hydrogenation-cracking were investigated. For the conversion of individual components: HAc was difficult to be hydrogenated, and therefore in the cracking stage, the conversion and oil phase yield were low; ketones were successfully hydrogenated to alcohols, and thus high aromatic hydrocarbon yields were achieved. Hydrogenation-cracking of SDF showed that the inferior performance of HAc was improved by an internal hydrogen transfer, namely the alcohols produced from ketones supplied hydrogen for HAc conversion. However, because of the high HAc content in SDF, this hydrogen supplement was not sufficient. Therefore, methanol (MeOH) was used as the coreactant for secondary hydrogen supply. The integral efficient conversion of SDF and MeOH to aromatic hydrocarbons was achieved when the MeOH blending ratio was 30%. Finally, a reaction mechanism of hydrogenation-cocracking was proposed.

  • Researchpp 5196-5211Yasin, S., Curti, M., Rovero, G., Behary, N., Perwuelz, A., Giraud, S., Migliavacca, G., Chen, G., and Guan, J. (2017). "An alternative for the end-of-life phase of flame retardant textile products: Degradation of flame retardant and preliminary settings of energy valorization by gasification," BioRes. 12(3), 5196-5211.AbstractPDF

    It is well established that current flame retardant (FR) products at disposal generate various ecological hazards. Irrespective of their environmental impacts, the FR market is growing and is estimated to reach 2.8 million tons globally in 2018. In the textile domain, FRs are incorporated into baby clothing, pushchairs, car seats, etc. When disposed, these FR textile products end up in a landfill or are incinerated. These disposal processes are unsustainable. With landfilling, there is a huge chance of the FR product leaching into the environment. Similarly, FRs decrease energetic yields in the incineration process due to incomplete combustion. To cope with such issues, degradation and elimination of the FR product from the textile products before disposal could be a sustainable alternative. This study dealt with the preliminary degradation of flame retardant from the cotton textiles and its thermal characterization. Energy valorization by gasification is considered beneficial opposed to incineration with overall low energy recovery. The initial optimum gasification conditions including FR-treated cotton as a feeding material and potential outcomes of FR-treated cotton after degradation were characterized.

  • Researchpp 5212-5222Saeed, H. A. M., Liu, Y., Lucian, L. A., and Chen, H. (2017). "Evaluation of Sudanese sorghum and bagasse as a pulp and paper feedstock," BioRes. 12(3), 5212-5222.AbstractPDF
    The suitability of specific Sudanese agrowastes, sorghum straw, bagasse, and their 50% blend, were investigated for pulp and papermaking initiatives. A chemical analysis of sorghum straw and bagasse revealed levels of cellulose, lignin, hemicellulose, and ash for sorghum straw and bagasse that signalled a suitable relation to traditional wood feedstocks for pulping and papermaking applications. Moreover, the pulp yield and viscosity of sorghum straw were lower and higher, respectively, compared with the bagasse and the blend. More specifically, the papers obtained from bagasse showed better physical properties (tensile strength, tearing index, bursting index, and folding) compared to those of sorghum straw and the blend. The surface morphologies of the papers were analysed using scanning electron microscopy (SEM), which showed that the fibres had a long, swollen, compact, and closely packed arrangement and were more homogeneous and well-blended for the bagasse compared with the pure sorghum straw and the 50% blend.
  • Researchpp 5223-5235Santanaraj, J., Sajab, M. S., Mohammad, A. W., Harun, S., Chia, C. H., Zakaria, S., and Kaco, H. (2017). "Enhanced delignification of oil palm empty fruit bunch fibers with in situ Fenton-oxidation," BioRes. 12(3), 5223-5235.AbstractPDF
    The degradation of lignin in oil palm empty fruit bunch (EFB) fibers by a low concentration of H2O2 was observed with the assistance of Fenton oxidation with Fe(III), Fe(0), and Fe3O4 as a catalyst. To escalate the oxidation activity toward lignin in the EFB fibers, the uptake of the Fenton reagent on the EFB fibers for in situ Fenton oxidation was optimized with fitted Langmuir and Freundlich adsorption models. The efficiency of assisted Fenton reagents was monitored through controlled parameters of H2O2 concentration, retention time, and increment of Fenton reagents. The delignification was observed with up to 71.2% of lignin degradation compared to 47.2% without the use of the Fenton reagents. The characteristics of EFB fibers after the oxidation process were changed based on the observation of morphological and chemical properties. The oxidation concurrently dislodged part of the silica bodies and disrupted specific functional groups and the crystallinity of the EFB fibers.
  • Researchpp 5236-5248Yun, N., and He, B. (2017). "Photo-induced yellowing of Mg(OH)2-based peroxide bleached deinked pulp," BioRes. 12(3), 5236-5248.AbstractArticlePDF

    The effects of ultraviolet (UV) irradiation on the changes in color and chemical structure of the surfaces of unbleached, PNaOH-, and PMg(OH)2- bleached deinked pulp (DIP) were studied by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The analysis of color changes in pulp surfaces during the photo yellowing was performed by measuring the brightness loss, post color (PC) number, and CIELAB parameters (L*, a*, b*, and ΔE*). The results showed that the pulp brightness loss, PC number, and chromatic aberration had a linear relationship with b*. During the UV irradiation, the pulp brightness loss, PC number, and chromatic aberration (ΔE*) increased quickly, and then the changes slowed down. After being irradiated with UV for 360 min, the band intensity of the pulps at 1729 cm-1 increased distinctively and a new band at 1674 cm-1 appeared. This indicated that p-quinone groups were produced during the irradiation process, thus resulting in paper yellowing. The band intensity at 1674 cm-1 of PMg(OH)2-bleached pulp was lower than that of PNaOH-bleached pulp, which indicated that the brightness stability of PMg(OH)2 pulp was better than that of PNaOH pulp.

  • Researchpp 5249-5263Zhou, W., Gong, Z., Zhang, L., Liu, Y., Yan, J., and Zhao, M. (2017). "Feasibility of lipid production from waste paper by the oleaginous yeast Cryptococcus curvatus," BioRes. 12(3), 5249-5263.AbstractArticlePDF

    Waste paper was studied as a potential source for lipid production using the oleaginous yeast Cryptococcus curvatus for the first time. Three common types of waste paper, office paper, newspaper, and cardboard, were directly hydrolyzed by an enzyme cocktail to generate sugar-rich and nitrogen-limited hydrolysates. When these hydrolysates were used without any auxiliary nutrients by C. curvatus, the lipid content and lipid yield were higher than 50% and 200 mg/g, respectively. The nitrogen-rich enzyme cocktail exerted no negative effects on lipid production. Moreover, the integrated processes of enzymatic hydrolysis and lipid fermentation achieved comparable lipid yield to the separate hydrolysis and lipid production process. The resulting lipid samples had similar fatty acid compositional profiles to those of vegetable oils, which suggested their potential for biodiesel production. These findings strongly supported waste paper as appealing substrates for lipid production via oleaginous yeast, which provided cost-effective waste paper-to-lipids routes for sustainable biodiesel production.

  • Researchpp 5264-5278Nathan, V. K., Esther Rani, M., Rathinasamy, G., and Narayanan Dhiraviam, K. (2017). "Low molecular weight xylanase from Trichoderma viride VKF3 for bio-bleaching of newspaper pulp," BioRes. 12(3), 5264-5278.AbstractArticlePDF
    Xylanase is a major enzyme used in the paper and pulp industries for bio-bleaching applications. There are possibilities for xylanase with better properties suitable for industrial applications. This paper focused on a potential xylanolytic fungus, Trichoderma viride VKF-3, obtained from a mangrove soil sample. Optimum conditions for xylanase production were tested by culturing T. viride VKF3 under varying carbon and nitrogen sources, medium pH, and incubation temperature. The isolate T. viride VKF3 achieved a maximum of 3.045 IU/mL of xylanase activity by utilizing coconut oil cake as a substrate. During purification, 84% yield was obtained with 40% ammonium sulphate. The enzyme activity was confirmed through zymogram analysis, and a band was observed at 14 kDa. The xylanase facilitated maximum hexenuronic acid release with a 30% enzyme dosage following 4 h of incubation. Moreover, the Kappa number tended to decrease with increased enzyme dosage and incubation time. There was a Δ brightness of 11% following 4 h of enzymatic treatment. Strength properties, such as the tensile, burst indices, and folding endurance, was improved during the xylanase assisted deinking of pulp. Hence, the present xylanase was found to be suitable for the bio-bleaching of newspaper waste via an eco-friendly process.
  • Researchpp 5279-5295Dogu, D., Tuncer, F. D., Bakir, D., and Candan, Z. (2017). "Characterizing microscopic changes of paulownia wood under thermal compression," BioRes. 12(3), 5279-5295.AbstractPDF

    This study evaluates the microscopic changes of paulownia solid wood panels subjected to thermal compression via characterizing the changes in wood microstructure. The panels, with dimensions of 500 mm × 100 mm × 20 mm, were hot-pressed in a tangential direction by using a laboratory-type hot press at a temperature of either 150 °C or 170 °C and a pressure of 2 MPa for 45 min. Microscopic investigations conducted by light microscopy showed that slightly more damage occurred in the samples compressed at 170 °C and 2 MPa than at 150 °C and 2 MPa, and that the distribution of deformation in the panels was not uniform in the growth rings of the two treatment groups. The cell collapse was not observed in the microstructure of paulownia wood after the thermal compression. Cell shapes and their arrangement in the growth ring alongside loading direction were interpreted as effective factors governing the non-uniform distribution of damage and the lack of cell collapse in the microstructure.

  • Researchpp 5296-5307Yu, L., Cai, J., Li, H., Lu, F., Qin, D., and Fei, B. (2017). "Effects of boric acid and/or borax treatments on the fire resistance of bamboo filament," BioRes. 12(3), 5296-5307.AbstractArticlePDF

    Bamboo filament, a material often used for indoor decoration, should be treated with flame retardants for safe use. This study evaluated the effects of different boron fire retardants on the heat release and smoke release of bamboo filaments and untreated samples via a cone analysis. A thermogravimetric analyzer (TA) instrument was used to investigate the fire retardant mechanisms of the different boron compounds. The results showed that compared to the untreated samples, fire retardants that contained boric acid or borax effectively reduced the heat and smoke release from the bamboo filament. The effects of the different ingredients in the fire retardant on the combustion process were quite different. During the combustion process, borax displayed better performance for restraining the heat release rate than boric acid, while for the total amount of heat release and the smoke suspension performance, the result was the converse. The excellent synergistic effect could be obtained by a mixture that contained a reasonable proportion of boric acid and borax (Boric Acid:Borax = 1:1). In the pyrolysis process, boric acid had stronger catalytic dehydration, while the mass loss in the treated samples with boric acid or higher proportions of boric acid was less than the loss in the borax-treated samples.

  • Researchpp 5308-5320Duan, D., Zhao, Y., Fan, L., Dai, L., Lv, J., Ruan, R., Wang, Y., and Liu, Y. (2017). "Low-power microwave radiation-assisted depolymerization of ethanol organosolv lignin in ethanol/formic acid mixtures," BioRes. 12(3), 5308-5320.AbstractArticlePDF

    Ethanol organosolv lignin separated from bamboo was depolymerized by low-power microwave radiation (~80 W) using ethanol as a swelling agent and formic acid as a hydrogen donor solvent. After increasing the temperature from 100 to 200 °C, the total amount of phenolic compounds in the products increased from 8.1% to 40.8%, and both the weight average molecular weight (Mw) and number average molecular weight (Mn) of the products from the lignin depolymerization decreased. With extended reaction time from 20 to 60 min, the total amount of phenolic compounds and molecular weight did not remarkably change. In addition, Fourier transform infrared (FT-IR) spectroscopy showed that oxidative fracture was the primary way that lignin depolymerized. The severity factor played an important role in converting lignin into small molecular substances, and the evaluation showed that the microwave temperature was more influential on the lignin depolymerization than the reaction time. Because depolymerization and repolymerization of fragments both occurred during the microwave radiation process, it is critical to inhibit repolymerization of degraded fragments for the efficient degradation of lignin. This study not only provides a theoretical basis for studying the mechanism of microwave-assisted lignin degradation but is also important for the determination of a cost-effective lignin depolymerization method.

  • Researchpp 5321-5342Aliberti, A., Ventorino, V., Robertiello, A., Galasso, M., Blaiotta, G., Comite, E., Faraco, V., and Pepe, O. (2017). "Effect of cellulase, substrate concentrations, and configuration processes on cellulosic ethanol production from pretreated Arundo donax," BioRes. 12(3), 5321-5342.AbstractArticlePDF

    Arundo donax was used to investigate the effect of the enzyme and substrate concentrations on hydrolysis, pre-hydrolysis and simultaneous saccharification and fermentation (PSSF), in comparison to simultaneous saccharification and fermentation (SSF). Hydrolysis was performed at 37 and 50 °C. At the highest biomass (10%) and enzyme (69.6 FPU/g cellulose) loadings, the highest glucose concentration (32.4 g/L) was obtained (at 50 °C). SSF resulted in a cellulose conversion (91.9%) and an ethanol concentration (19.8 g/L) higher than what was obtained using PSSF at 37 °C (86.9% and 18.8 g/L, respectively) and PSSF at 50 °C (81.6% and 17.7 g/L, respectively). A positive correlation between the cellulase concentration, cellulose conversion, and ethanol content was observed. In PSSF, the increase in the solids loadings caused a reduction in the % cellulose conversion, but the ethanol concentration in PSSF and SSF increased. SSF appeared to be the most advantageous process for bioethanol production from A. donax.

  • Researchpp 5343-5357Zhang, X., Jin, C., Jiang, Y., Liu, G., Wu, G., and Kong, Z. (2017). "A novel gallic acid-grafted-lignin biosorbent for the selected removal of lead ions from aqueous solutions," BioRes. 12(3), 5343-5357.AbstractArticlePDF

    The low content of phenolic groups limits the application of lignin-based materials as biosorbents for the removal of metal ions. In this work, a novel gallic acid-grafted-lignin (GAL, 4.43 mmol/g hydroxyl group) biosorbent was designed by introducing gallic acid moieties to replace the hydroxyl groups of lignin. These grafted polyphenolic groups provide additional sites for the adsorption of metal ions. The structure of GAL was characterized by FT-IR, 31P NMR, and 13C NMR spectroscopy. The adsorption properties of GAL for Pb(II) ions were investigated under batch conditions. Kinetic and isothermal adsorption processes could be well-described by the pseudo-second order kinetic model and Langmuir isothermal model, respectively. The grafting of polyphenolic groups onto lignin increased the maximum adsorption capacity of the adsorbent for Pb(II) (119.1 mg/g). The adsorption thermodynamics indicated that the adsorption process was endothermic and spontaneous. In addition, GAL could selectively adsorb Pb(II) with a selectivity coefficient (k) at 1.89 in the presence of coexisting metal ions from aqueous solution. The high adsorption capacity and selectivity for Pb(II) by GAL, together with its environmental compatibility, enable this material to act as a promising biosorbent for removing heavy metal ions from polluted water.

  • Researchpp 5358-5368Genc, G., and Koruk, H. (2017). "Identification of the dynamic characteristics of luffa fiber reinforced bio-composite plates," BioRes. 12(3), 5358-5368.AbstractPDF

    Luffa cylindrica plant fiber is a new biodegradable engineering material. However, the dynamic behaviors of these new green materials or their composites should be explored to consider them for practical applications. The dynamic characteristics including modal behavior and the elastic and sound isolation properties of luffa-based bio-composite plates were explored in this study. Structural frequency response function measurements were conducted using a few luffa bio-composite plates to identify their modal behavior. The modal frequencies and loss factors of the luffa bio-composite plates were identified by analyzing the frequency response function measurements using a few modal analysis methods such as half-power, circle-fit, and line-fit. The same luffa bio-composite structures were modelled using a finite element formulation with damping capability, and the elastic moduli of the composite plates were identified. In addition, the transmission loss levels of the same luffa composite samples were measured using the impedance tube method. The results showed that luffa composite structures have considerably high stiffness (elasticity modulus: 2.5 GPa), damping levels (loss factor: 2.6%), and transmission loss level (25 to 30 dB for a 1 cm thickness), and their mechanical properties are promising as an alternative disposable material for noise and vibration control engineering applications.

  • Researchpp 5369-5382Wu, J., Wang, M., and Guo, H. (2017). “Synergistic flame retardant effects of different zeolites on intumescent fire retardant coating for wood,” BioRes. 12(3), 5369-5382.AbstractPDF

    To investigate the fire-retardant properties of intumescent fire-retardant coatings of wood modified by different zeolites, tests were conducted by a cone calorimeter with poplar samples whose surfaces were covered by an intumescent fire-retardant coating modified by 3A, 4A, 5A, 13X zeolites, respectively. Results indicated that the ignition time (TTI) of the intumescent fire-retardant coating modified by 3A zeolite was prolonged 120 s, while the total smoke production (TSP) increased 60.1% as compared with the untreated group. The intumescent fire-retardant coating modified by the 13X zeolite had a smaller smoke production rate (SPR) and was the last to reach the peak-SPR. Its TSP remained in a very low state until 410 s and decreased 25%. Thus, 3A zeolite and 13X zeolite were of complementarily synergistic effects on improving the fire-retardant properties of an intumescent fire-retardant coating for wood. This paper suggested the alternative types of zeolites for flame-retardant coatings.

  • Researchpp 5383-5394Ramos, D., Salvadó, J., and Fernando, F. (2017). “High mechanical performance boards made from fibers of Arundo donax without added adhesives,” BioRes. 12(3), 5383-5394.AbstractArticlePDF

    Arundo donax is a cane species with high growing productivity, and it is becoming an important source of biomass. The main objective of this study was to obtain fibreboards with high mechanical performance from A. donax without any added adhesive. Boards made without adhesive are free from formaldehyde emissions and consume no fossil resources. The characteristics of the obtained boards depended on the original material, steam explosion pre-treatments, and forming conditions (pressure, temperature, and pressing time). Production parameters were optimized. The effect of forming pressure on the physical and mechanical properties density, elastic modulus (MOE), modulus of rupture (MOR), tensile strength perpendicular to the faces (IB), thickness swelling, and water absorption of the obtained boards was studied. The European Norms (EN) methodologies were used to test the board specifications. Density, MOE, and MOR were modelled by a double reciprocal function. TS and WA were modelled with a reciprocal function in X. The boards obtained met and sometimes exceeded the requirements of these standards for the most demanding structural use.

  • Researchpp 5395-5406Ji, X., Zhang, Z., Chen, J., Yang, G., Chen, H., and Lucia, L. A. (2017). "Synthesis and characterization of alkali lignin-based hydrogels from ionic liquids," BioRes. 12(3), 5395-5406.AbstractArticlePDF

    Hydrogels from alkali lignin were prepared and shown to display unique swelling. Variable lignin contents (6.25%, 10.00%, 12.50%, and 14.29%) were successfully grafted with both N,N’-methylenebisacrylamide (MBA) and acrylamide (AM). Ionic liquids such as 1-ethyl-3-methylimidazolium acetate ([Emim]Ac) were used to avoid harsh, unfriendly solvents. All materials were characterized using X-ray diffraction (XRD) FT-IR spectroscopy, scanning electron microscope (SEM), thermogravimetric analysis (TGA), and swellability. The swelling behaviors of the hydrogels were noticeably influenced by their lignin content. The degree of equilibrium swelling (the maximum swelling degree) decreased with increasing content of lignin. The highest swelling degree (1,650%) was obtained at 6.25 wt% lignin. Kinetics revealed that the swelling behaviors of hydrogels were well-fitted by the Schott model.

  • Researchpp 5407-5416Liu, R., Chen, Z., Ren, H., and Duan, E. (2017). "Synthesis and properties of non-aromatic ionic liquids and their role in cellulose dissolution," BioRes. 12(3), 5407-5416.AbstractArticlePDF

    The dissolution of cellulose is an important pretreatment method required for some of its catalytic conversion processes. Morpholinium-based ionic liquids (ILs) are challenging solvent choices available for “greener” and “cheaper” dissolution of cellulose. In this study, morpholinium-based ILs were prepared, and their influencing factors were experimentally investigated. The unique bipolar chemical structure derived from oxygen (electron-rich center) and nitrogen (electron-poor center) considerably enhanced the Hammett acidity function (H0) of task-ILs. N-Methyl-N-allyl-morpholinium acetate IL showed the highest H0 (2.324) and polarizability power (1.096). The anion of ILs determined the hydrogen bond basicity (β). The acetate anion contributed to β (0.88) values. As to fluid properties, the morpholinium-based ILs exhibited much lower viscosity. The properties of ILs improved the dissolution efficiency. The cellulose was directly dissolved in morpholinium-based Ils, and no other derivatives were formed. The cations and the anions of ILs studied reacted with oxygen and hydrogen atoms on the hydroxyl groups of cellulose, respectively.

  • Researchpp 5417-5427Seo, H. J., Hwang, W., and Lee, M. C. (2017). "Fire properties of Pinus densiflora utilizing fire-retardant chemicals based on borated and phosphorus (I) – combustion characteristics," BioRes. 12(3), 5417-5427.AbstractPDF

    The combustion and thermal characteristics of fire retardant-treated pine (Pinus densiflora) were evaluated according to the KS F ISO 5660-1 (2003) standard, using a cone calorimeter. The specimens were treated with fire-retardant chemical compounds using pressure-impregnation equipment to reliably impregnate the compounds inside the wood. The heat release rate value of the fire retardant-treated wood specimens showed that the heat release time was delayed. A reduction of the total heat release value can indicate that fire was prevented from igniting in the materials during combustion. The microstructures of natural specimen and treated fire-retardant chemical compounds specimen were determined by scanning electron microscopy. It also confirmed that the pressure-impregnation processing method was effective in comparison to the other treatment methods.

  • Researchpp 5428-5448Ramos-Carmona, S., Delgado-Balcázar, S., and Perez, J. F. (2017). "Physicochemical characterization of torrefied wood biomass under air as oxidizing atmosphere," BioRes. 12(3), 5428-5448.AbstractPDF

    The effects of torrefaction under an oxidizing atmosphere on the physicochemical properties of patula pine wood chips were studied. Raw and torrefied pine were characterized to evaluate the effect of temperature and residence time on biofuel properties, such as bulk density, equivalent Hardgrove grindability index (HGIeq), ultimate and proximate analyses, heating value, and fuel value index (FVI). In contrast, the torrefaction process was characterized by mass and energy yields, and by the energy-mass co-benefit index (EMCI). Torrefaction was performed in a rotary kiln at temperatures between 180 °C and 240 °C during residence times between 30 min and 120 min. The torrefaction process under an oxidizing atmosphere tended to increase the fixed carbon/volatile matter ratio (from 0.19 to 2.5), while the H/C and O/C atomic ratios decreased 73% and 55%, respectively. The best properties of wood reached in the experimental plan were obtained at 210 °C during 75 min. For this torrefaction condition, energy yield, FVI, and EMCI were 85.91%, 1.91 MJ/cm3, and 4.41%, respectively. Additionally, the lower heating value for torrefied pine (18.65 MJ/kg) was higher than for the raw material (17.76 MJ/kg), and the HGIeq was 17% greater, which resulted in a better grindability behavior.

  • Researchpp 5449-5461Valášek, P., Müller, M., and Šleger, V. (2017). "Influence of plasma treatment on mechanical properties of cellulose-based fibres and their interfacial interaction in composite systems," BioRes. 12(3), 5449-5461.AbstractPDF
    The use of natural reinforcements is growing in current material engineering due to their satisfactory mechanical properties such as availability, price, and environmental aspects. Synthetic fibres are more often replaced by natural ones in many applications. The interfacial interactions of matrices are key factors that limit the use of natural fibres. The matrix interactions of natural fibres can be optimized by surface treatments, such as plasma treatment. This paper examined the possibility of using plasma to treat natural fibres. The basic mechanical characteristics of the fibres were changed by this treatment. Changes in the surface structures and the subsequent interaction with polymeric matrices with epoxy resins were evaluated by scanning electron microscopy. The plasma treatments of fibres did not decrease the tensile strength but did optimize their surface structures.
  • Researchpp 5462-5486Zhang, Z. C., Li, J. H., and Wang, F. (2017). "Kinetics of cellulase saccharification of corn stover after pretreatment by lignin peroxidase and H2O2," BioRes. 12(3), 5462-5486.AbstractPDF

    The kinetics of cellulase saccharification of corn stover (CS) after pretreatment by lignin peroxidase (LiP) and H2O2 was modeled in this work. The Impeded Michaelis model was applied in fitting all experimental data. The model gave the initial activity and accessibility of the enzyme on the substrate (Kobs,0) and the gradual loss of enzyme activity (Ki). The maximum Ytrs (55.56%) was obtained at pH 4.7, 48.6 °C, a 1.5% cellulase, and 12.4:1 water-to-material ratio. The binary quadratic model provide a good fit of the data on Ytrs and of the model parameters Kobs,0 and Ki. The results showed that Ytrs was positively correlated with Kobs,0 and negatively correlated with Ki. This study laid a foundation for improving the cellulase saccharification efficiency of lignocellulosic biomass after pretreatment by H2O2 and LiP.

  • Researchpp 5487-5501Bailón-Salas, A., Ordaz-Díaz, L., Valle-Cervantes, S., Lopez-Miranda, J., Urtiz-Estrada, N., Páez-Lerma, J., de León-Mata, G., and Rojas-Contreras, J. (2017). "Bacterial diversity in two aerated lagoons of a pulp and paper effluent and their interaction with a commercial inoculum using PCR-DGGE," BioRes. 12(3), 5487-5501.AbstractPDF
    Aerated lagoons are a main unit operation for wastewater treatment in the paper industry. Many such operations involve inoculation with bacterial formulations in which in situ effectiveness has not been proven; this can be translated into low efficiency in treatment and unnecessary investments. Lack of knowledge of bacterial biodiversity present in a lagoon limits the capacity to exploit the maximum degradation. To overcome such problems, various methods to identify and study these microorganisms have been developed. In this study, a PCR-DGGE analysis was performed to estimate the bacterial diversity and to verify the presence of bacteria present in a commercial inoculum in two aerated lagoons of a pulp and paper effluent. Phylogenetic affiliation of predominant member’s correspondent to γ- and β-proteobacteria and Firmicutes were found. The dominant bacteria present in lagoon 2 belonged to the following genus Microbacterium sp. Rhodocyclaceae sp., Eubacterium sp. and B. subtilis. In lagoon 1 the dominant genus included Microbacterium sp., Rhodocyclaceae sp. Tepidimonas sp., Acetanaerobacterium sp., and Flavobacteria sp. The two characterized lagoons were not similar to the commercial inoculum. In addition, non-dominant bacteria (less relative intensity) were composed mostly of bacteria of the commercial inoculum.
  • Researchpp 5502-5511Shi, Y., Xie, J., Kou, J., Kong, R., Sun, N., and Bai, M. (2017). "Decomposition study of methyl α-D-glucopyranoside (MGPα) and lignin model compounds for better glucose yield during sulfurous acid treatment," BioRes. 12(3), 5502-5511.AbstractArticlePDF

    From the perspective of bio-refinery, sulfurous acid (H2SO3) treatment of lignocellulosic biomass is attractive because of its ability to act both as an acid catalyst and as a sulfonation agent. Therefore, its capability to hydrolyze polysaccharides (especially glucan) into monosaccharides was compared with two other acids, hydrochloric and sulfuric acids. The decomposition of methyl α-D-glucopyranoside (MGPα) in these three acids, hydrochloric, sulfuric, and sulfurous acids were studied. In addition, p-creosol and vanillyl alcohol were introduced to check whether it is possible to convert polysaccharides (such as hemicelluloses) into monosaccharides during the sulfurous acid treatment. The results showed that the decomposition of MGPα is much slower in H2SO3 than in HCl and H2SO4. The ligninsulfonic acid resulting from the lignin sulfonation reaction can be expected to improve the efficiency of hydrolysis of polysaccharides into monosaccharides during sulfurous acid treatment. Moreover, a higher actual yield of glucose was obtained in this case than in the other two acids.

  • Researchpp 5512-5524Urbaniak, M., Goluch-Goreczna, R., and Bledzki, A. (2017). "Natural cork agglomerate as an ecological alternative in constructional sandwich composites," BioRes. 12(3), 5512-5524.AbstractArticlePDF

    The investigations presented in this article include a comparative study of static and fatigue four-point flexural tests performed for sandwich composites. The investigated composites consisted of a glass-epoxy laminate as a cladding material and core materials, such as synthetic foams and natural cork agglomerates, in different densities. The sandwich composites were prepared with the vacuum bagging method using the same resin, reinforcement, and additives. Although using cork agglomerate in sandwich composites instead of synthetic foam resulted in a decrease of the static flexural strength in such composites, it increased their resistance to fatigue cycles considerably and benefitted their eco-friendly image. However, only the reproducibility of all the factors in the production process and testing of composites allows a direct comparison of their test results to be made.

  • Researchpp 5525-5538Grič, M., Joščák, P., Tarvainen, I., Ryönänkoski, H., Lagaňa, R., Langová, N., and Andor, T. (2017). "Mechanical properties of furniture self-locking frame joints," BioRes. 12(3), 5525-5538.AbstractPDF
    The load carrying capacity, stiffness, and strain fields of 18 mm thick and half lap 30 mm thick L-shaped furniture self-locking frame joints made of a Finnish birch plywood and a birch battenboard were determined. The joints were tested under tensile and compression bending. On the basis of the experimental information, finite element analysis models were verified. The data showed that the joints made of birch plywood reached a higher load carrying capacity and stiffness than the joints made of the birch battenboard with the same thickness. The Half lap joint (H L J) made of the Finnish plywood reached the ultimate load carrying capacity and the ultimate stiffness under both the compression bending and the tensile bending. The finite element analysis models of the joints can be used for estimating the mechanical properties of the self-locking joints with different tenon shapes made of the materials used in this paper.
  • Researchpp 5539-5549Gu, L., Li, Y., Yang, Y., Wang, Z., and Jin, Y. (2017). "Preparation and adsorption performance of cellulose-graft-polycaprolactone/polycaprolactone porous material," BioRes. 12(3), 5539-5549.AbstractPDF

    Cellulose-graft-polycaprolactone/polycaprolactone (cell-g-PCL/PCL) was formed by grafting cotton linter pulp with caprolactone via ring-opening polymerization catalyzed by Ti(O-n-Bu)4. The cell-g-PCL/PCL and polycaprolactone (PCL) were used to prepare porous materials (PMs) using solvent exchange and freeze-drying procedures. The obtained PMs were characterized by their porosity, tensile strength, and thermal stability via thermal gravimetric analysis and scanning electron microscopy. The preparation conditions of the cell-g-PCL/PCL PM were optimized based on the characterization results. Compared with PCL PM, cell-g-PCL/PCL PM showed higher porosity and better thermal stability. The adsorptivity of cell-g-PCL/PCL PM for the organic pollutant chlorobenzene was greatly improved compared with that of PCL PM. The adsorption processes of both PMs fit well with the Lagergren pseudo-first-order and pseudo-second-order kinetic models. The results of isothermal adsorption simulation indicated that cell-g-PCL/PCL PM and PCL PM fit better with the Langmuir model and Freundlich model, respectively.

  • Researchpp 5550-5568Kim, N. K., and Rie, D. H. (2017). "A study on fire risk reduction of porous combustible storage," BioRes. 12(3), 5550-5568.AbstractPDF

    As biomass has become increasingly important, wood pellets are becoming more widely used, and the storage of wood flour, which is the raw material of wood pellets, has become inevitable. The purpose of this study was to reduce the economic losses from fires during storage of porous combustible materials. To achieve this purpose, the authors analyzed and compared the wood flour loss rate between the use of water and the use of wetting agents to extinguish a deep-seated fire through a scale model experiment. To do this, the authors measured the penetration amount of the water and dilute solutions of wetting agent, the weight change of the wood flour holder, and the emissions on a real time basis when that spray amount was the same. Furthermore, the authors analyzed the calorific value and combustion gas to examine the reusability of the wood flour with the added wetting agent. This study quantitatively demonstrated that the active use of wetting agents in wood flour storage fires dramatically reduced the fire loss rate of raw materials and resulted in early fire extinguishing, which minimizes companies’ economic loss.

  • Researchpp 5569-5582Merhar, M., Gornik Bučar, D., and Pepelnjak, T. (2017). "Dynamic behaviour analysis of a commercial roll-tensioned circular sawblade," BioRes. 12(3), 5569-5582.AbstractPDF

    A commercial woodcutting circular sawblade was analysed in this work. The lateral stiffness on the periphery was measured, and the natural frequencies were determined by modal analyses. The sawblade was modelled by the finite element method, where the influence of the internal stresses caused by roll-tensioning of the sawblade was considered. The roll-tensioning force was determined based on the measurement of the sawblade rolling profile, where it was established that the sawblade had been rolled with a force of 7800 N. The analysis showed that at the aforementioned force, the lateral stiffness was a maximum; here, the calculated and measured stiffnesses were 81 and 60 N/mm, respectively. The calculated natural frequencies agree well with the measured ones, where in the most important vibrational modes there is only a 7% difference. The maximum rotational speed for the sawblade was determined to be 85% of the critical speed. Because the sawblade was clamped with a ratio of clamping of only 0.25, the maximum rotational speed was amounted to 6630 rpm. Increasing the rolling force would increase the critical speed but greatly reduce the lateral stiffness.

  • Researchpp 5583-5600Ouyang, H., Wang, L., Peng, W., and Deng, H. (2017). "Fungus-assisted acetic acid pre-treatment of Eucommia ulmoides Oliver seed shells for enhancement of enzymatic hydrolysis," BioRes. 12(3), 5583-5600.AbstractPDF

    The potential of nine fungal strains for pre-treating Eucommia ulmoides Oliver seed shells (EUOSSs) was investigated. Phanerochaete chrysosporium Burds. was found to be the best fungal strain for pre-treating EUOSSs. After co-pre-treatment with acetic acid and P. chrysosporium Burds., which was cultivated in a solid state with an approximately 74% moisture content at 28 °C for 28 d, the weight loss of the EUOSSs was 51.9%. Because of the cooperative efficiency of the biochemical pre-treatment, an enzymatic digestibility value of 86.6% was achieved. The high digestibility value was attributed to the synergism between the acetic acid and fungal treatments, which led to improved enzymatic accessibility of the EUOSSs. As an environmentally friendly processing method, fungal pre-treatment can save a great amount of energy and, in combination with an acetic acid treatment, is more efficient at improving the rate of sugar transformation.

  • Researchpp 5601-5616Chen, X., Han, Y., Zhang, C., Feng, G., Zhao, M., Yue, R., Li, Y., Jiang, L., Zhang, L., Li, J., and Li, S. (2017). "Alkaline pretreatment of banana stems for methane generation: Effects of temperature and physicochemical changes," BioRes. 12(3), 5601-5616.AbstractPDF
    The effects of NaOH pretreatment temperature on the physicochemical characteristics and methane production of anaerobically digested banana stems were investigated in this paper. With the increase of pretreatment temperature from 0 °C to 100 °C, the chemical oxygen demand (COD) of the soak liquid in the treated biomass approximately linearly increased from 5.9 g/L for the untreated stems to 34.0 g/L. A weight loss of 5.1% was observed for the untreated material, while it was up to 31.2% for the sample treated at 100 °C. The removal of lignin and hemicellulose accounted for the majority of the weight loss. The removal rates of lignin and hemicellulose increased from 15.0% to 41.6% and 1.9% to 23.6% when the treatment temperature increased from 0 °C to 100 °C, respectively. Moreover, the crystalline index (CI) of the banana stems also increased with rising temperature, resulting from the dissolution of amorphous cellulose with increasingly harsher alkaline environments. The optimal pretreatment temperature for banana stems was confirmed at 50 °C. In these conditions, methane was produced via anaerobic digestion with 239.9 mL/g total solid (TS) yield, which represented an increase of 66.7% over untreated banana stems.
  • Researchpp 5617-5631Mahgoub, K. B., Hassan, S., Sulaiman, S. A., Mamat, R., Abdullah, A. A., and Hagos, F. Y. (2017). "Combustion and performance of syngas dual fueling in a CI engine with blended biodiesel as pilot fuel," BioRes. 12(3), 5617-5631.AbstractPDF

    Simulated syngas produced from biomass gasification was evaluated in a compression ignition (CI) engine under a dual fueling mode. Syngas is an economical solution with a carbon-neutral system that could replace petroleum diesel fuel. Syngas can be introduced into CI engines through a dual fueling process. However, syngas dual fueling combustion is very complicated because it consists of several combustion phases. In addition, CI engines operating under the syngas dual fueling mode suffer from low performance. Therefore, this study examined the performance of syngas dual fueling in a CI engine with blended biodiesel as pilot fuel. Two types of simulated syngas, namely typical syngas and high hydrogen syngas, were considered. The simulated high hydrogen syngas was assumed to be the product of biomass gasification with introduction of a carbon dioxide adsorption. The effect of carbon dioxide removal from syngas on the performance of syngas dual fueling in a CI engine at constant engine speed, half load, and different pilot fuel substitution rates was investigated. The combustion characteristics showed a maximum pilot fuel substitution of up to 47% with simulated syngas. Better engine performance was achieved with the simulated typical syngas in terms of brake specific energy consumption and brake thermal efficiency.

  • Researchpp 5632-5648Hutterer, C., Fackler, K., Schild, G., Ibl, V., and Potthast, A. (2017). "Xylan localization on pulp and viscose fiber surfaces," BioRes. 12(3), 5632-5648.AbstractPDF

    A method for the immunological visualization of plant polysaccharides in native plant tissues was adopted for the histological investigation of xylan on kraft pulp and xylan-enriched viscose fibers. The method consisted of the selective labeling of xylan structures through the binding of specific monoclonal primary antibodies and fluorescein isothiocyanate (FITC)-carrying secondary antibodies. This indirect immunolabeling method was adapted for pulp and viscose fibers through the blockage of unspecific binding sites with bovine serum albumin (BSA), which allowed a selective localization of xylan. The combination of this technique with high resolution confocal laser scanning microscopy (CLSM) rendered a parallel detection of morphological changes of pulp fibers alongside various processing steps possible. Within this study, kraft pulps from birch, beech, and eucalyptus were investigated throughout a purification process that enabled an upgrade from paper pulps to dissolving pulps by caustic hemicellulose extraction and xylan-enriched viscose fibers. The method demonstrated its potential for gaining novel insights into pulp purification, as well as fiber modification through the application of an immunolabeling method.

  • Researchpp 5649-5663Imran, M., Anwar, Z., Zafar, M., Irshad, M., and Iqbal, T. (2017). "Hyper-productivity, characterization, and exploitation of a cellulase complex from a novel isolate of Aspergillus tubingenesis S2 using lignocellulose-based material," BioRes. 12(3), 5649-5663.AbstractPDF

    The hyper-production potential of a cellulase complex from a local strain of Aspergillus tubingensis S2, indigenously isolated from rotten tomato, was investigated. A total of nine fungal species of Aspergillus and Trichoderma were isolated and confirmed through triple-phase screening via 18S ribosomal DNA sequencing and construction of a phylogenetic tree. Congo red testing and the zone of clearance method were used to confirm the cellulase production from A. tubingenesis S2 isolate. A. tubingenesis S2 revealed maximum cellulase production (78 µg/mL/min) and was selected for further study. The optimum fermentative conditions, including the incubation period, pH, and temperature values, were determined to be 96 h, pH 4.8, and 40 °C, respectively, for obtaining the cellulase activity of 86.4±2.1 µg/mL/min. The cellulase was 5.14-fold purified by ammonium sulfate fractionation and gel permeation chromatography. Characterization revealed that maximum activity (130.5 µg/mL/min and 133.5 µg/mL/min) was achieved at 4.5 pH and 40 °C, respectively. A monomeric protein with an apparent molecular weight of 76 kDa was evident after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Cellulase revealed maximal activity with 40-mesh size corn stover as compared with 20-mesh size corn stover and 80-mesh size corn stover after 36 h of incubation at 40 °C.

  • Researchpp 5664-5681Bekele, L. D., Zhang, W., Liu, Y., Duns, G. D., Yu, C., Jin, L., Li, X., Jia, Q., and Chen, J. (2017). "Preparation and characterization of lemongrass fiber (Cymbopogon species) for reinforcing application in thermoplastic composites," BioRes. 12(3), 5664-5681.AbstractPDF

    Lemongrass fiber was analyzed to determine the chemical proportion of its lignocellulosic components. Fibers’ thermal behavior, surface structures, and functionality were assessed by thermogravimetric analysis (TGA), scanning electron microscope (SEM), and Fourier transform-infrared spectroscopy (FT-IR), respectively. High-density polyethylene (HDPE) matrix composites filled with varying (10%, 20%, 30%, 40%, and 50%) fiber content were prepared and investigated. Composite wicker was made from HDPE and low density polyethylene (LDPE) blend-matrix and 10% alkaline modified fiber. Alkaline or maleic anhydride grafted polypropylene (MA-g-PP) was used to improve the compatibility between the fiber and matrices. The composites were evaluated by using TGA, SEM microscopy, and universal testing machine, respectively. The fiber was constituted by equitable amounts of lignocellulosic components with cellulose accounting for the highest proportion. It also exhibited high degradation temperature, which was further increased following alkaline modification. Superior thermal degradation behavior was measured for modified fiber composites. SEM showed that the modified fiber composites demonstrated better compatibility. Lemongrass fiber reinforcement substantially improved the mechanical properties of the composites.

  • Researchpp 5682-5696Bharimalla, A., Deshmukh, S., Patil, P., and Nadanathangam, V. (2017). "Micro/nano-fibrillated cellulose from cotton linters as strength additive in unbleached kraft paper: Experimental, semi-empirical, and mechanistic studies," BioRes. 12(3), 5682-5696.AbstractPDF

    Microfibrillated cellulose (MFC) and nanofibrillated cellulose (NFC) isolated from cotton linters were evaluated as a strength additive in unbleached kraft paper and compared with semi-empirical and mechanistic models. The z-directional tensile strength was enhanced due to NFC and MFC. The tensile energy absorption (TEA) derived via integrating the z-directional stress-strain curve was 29.165 J/m2, 120.658 J/m2, and 187.768 J/m2 for the control, MFC, and NFC, respectively. Burst factor significantly increased from 11 to 14 for 10% MFC, while no increase was observed in NFC. From TEA predictions by semi-empirical models, a modified Page equation, Shear-lag, and a negative trend was found due to increased relative bonded area (RBA) with the addition of MFC/NFC. The mechanistic model used six mechanisms involved in binding the fibers and predicted the increased trend of TEA. The increased TEA due to NFC contributed to z-directional tensile strength, but not to the tensile indices and tear factor. This was ascribed to the large size difference of NFC with base pulp fibers and a higher RBA.

  • Researchpp 5697-5714Burry, W., Doelle, K., Liu, S., and Appleby, R. (2017). "Common reed (Phragmites australis), eradicate or utilize? Part II: Potential use as an industrial fiber source after hot water extraction," BioRes. 12(3), 5697-5714.AbstractPDF

    The potential usefulness of an invasive common reed as biomass feed to a biorefinery was investigated. This investigation focused on the cellulosic fiber and a comparison of with and without a hot-water extraction (HWE) pretreatment process step. Handsheets were made before and after bleaching and compared to handsheets made from other pulped grass family (Poaceae) fibers. Machine-made simulated copy-grade paper was compared with and without HWE at varied percentages of reed replacement for hardwood fiber in the furnish. The HWE appeared to cause a dramatic increase in the tensile and burst strength while the tear strength reduced slightly. The effects of HWE on woody biomass strength properties were compared.

  • Researchpp 5715-5735Sam-Brew, S., and Smith, G. D. (2017). "Flax shive and hemp hurd residues as alternative raw material for particleboard production," BioRes. 12(3), 5715-5735.AbstractPDF

    Flax shive and hemp hurd residues were characterized, and the feasibility of manufacturing three-layered particleboards was evaluated using 2.5% and 5% polymeric diphenyl methane diisocyanate resin loadings. The flax shive and hemp hurd residues had lower bulk densities and higher aspect ratios compared with the wood residues. Their higher aspect ratios offered greater overlap in bonding, which led to consistently higher bending properties that exceeded the American National Standards Institute (ANSI) requirements for low-density (LD2) particleboard and, in some cases, medium-density (M2) particleboard. Because of their particle geometry, the flax shive and hemp hurd particleboards also showed minimal linear expansion with changes in the moisture content at 20 ± 3 °C and between 50% and 90% relative humidity. The high absorption capacity of the flax shive and hemp hurd residues resulted in higher thickness swell and water absorption properties than the wood residues. The results indicated that low-density flax shive and hemp hurd particleboards (500 to 620 kg/m3) can be manufactured using isocyanate resin quantities as low as 2.5% to produce panels that conform to ANSI specifications with a greater mechanical performance than that of wood residue particleboards.

  • Researchpp 5736-5748Xia, T., Huang, H., Wu, G., Jin, X., Sun, E., and Tang, W. (2017). "Study on the acetylation of rice straw-biogas residue and its characteristic effect on rice straw-reinforced composites," BioRes. 12(3), 5736-5748.AbstractPDF

    To improve the compatibility between rice straw and reinforcing polymers, rice straw (RS) was pretreated by an anaerobic process, and its biogas residues (BR) were acetylated with acetic anhydride (AA) to prepare acetylated biogas residues (ABR). The optimum conditions of acetylation were determined by orthogonal experiments. When acetylation was performed at 140 °C with 10 mL AA/g BR and 0.08 g catalyst/g BR, the maximum weight gain rate (WGR) obtained was 23.7%. Fourier transform infrared (FTIR) analysis showed that many hydroxyl groups were displaced by acetoxy groups. Scanning electron microscopy (SEM) showed that many defects of BR were filled by the acetylation, and an ester layer was formed over the BR surface. However, the lower crystallinity of ABR than the BR and RS affected the mechanical properties of acetylated biogas residue/low density polyethylene (ABR/LDEP) composite. Interestingly, the BR and ABR showed higher onset decomposition temperature, but they exhibited faster decomposition rates because of the lower crystallinity of BR and ABR. Furthermore, the mechanical properties of the RS/LDEP, BR/LDEP, and ABR/LDEP composites were analyzed. Compared with RS/LDEP composites, the BR/LDEP and ABR/LDEP composites showed obviously better tensile and flexural properties. Consequently, rice straw fibers attained excellent compatibility with non-polar polymers.

  • Researchpp 5749-5774Zakaria, S. M., Idris, A., and Alias, Y. (2017). "Lignin extraction from coconut shell using aprotic ionic liquids," BioRes. 12(3), 5749-5774.AbstractPDF

    Coconut shell, a natural biopolymer, is available in high amounts as waste in many countries. It could potentially be a crucial renewable source of raw materials for the carbon fiber industry. In this study, a series of aprotic ionic liquids, [Bmim][Ace], [Bmim]Cl, [Emim][Ace], and [Emim]Cl, were used in the dissolution and regeneration process of coconut shell. The results indicate that the dissolution of coconut shell (up to 70 mg of coconut shell per g of solvent) can occur in aprotic ionic liquids under a nitrogen atmosphere at 110 °C (6 h) and 150 °C (2 h). The extraction efficiency was greatly influenced by temperature, time, particle size, and types of cations and anions in the ionic liquids. At 150 °C, 10% regenerated lignin was obtained in [Emim][Ace], which was higher compared with [Emim]Cl, [Bmim][Ace], and [Bmim]Cl. The recyclability of the ionic liquids during the dissolution process (up to four times) was also scrutinized. The structure and properties of the untreated coconut shell and regenerated lignin were characterized by Fourier transform infra-red (FTIR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) analysis, and proton nuclear magnetic resonance (1H NMR).

  • Researchpp 5775-5789Dang, C., Xu, M., Yin, Y., and Pu, J. (2017). "Preparation and characterization of hydrophobic non-crystal microporous starch (NCMS) and its application in food wrapper paper as a sizing agent," BioRes. 12(3), 5775-5789.AbstractPDF

    Non-crystal microporous starch (NCMS) containing microporous and amorphous structures was prepared from native corn starch by heat treatment and solvent exchange. NCMS can be used as fillers, coatings, and raw materials in the preparation of various denatured starch because of its specific surface area and amorphous region. However, the hydrophilicity of NCMS limits its applications in papermaking. Thus, in this study, NCMS was reacted with alkyl ketene dimer (AKD) to prepare hydrophobic NCMS (H–NCMS), which is more stable, and convenient for storage and use in surface sizing. The optimal preparation conditions were selected using single-factor tests. The product, which was prepared at 55 °C for 3 h with an AKD dosage of 80%, had a sizing degree of 67 s. Characterization by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) spectroscopy confirmed that NCMS, H–NCMS, and sized paper were obtained. The thermal stability and hydrophobicity of the paper were measured using thermogravimetric analysis (TGA) and water contact angles, respectively. The results indicated that the sized paper has excellent thermal stability and hydrophobicity after surface sizing with 0.9% H–NCMS. Food wrapping paper with excellent strength and hydrophobicity was successfully prepared using H–NCMS and ultrasonic-assisted wheat straw pulp (UWP).

  • Researchpp 5790-5800Monteiro, T. C., Lima, J., T., Silva, J. R. M., Trugilho, P. F., and Baraúna, E. E. P. (2017). "Energy balance in sawing Eucalyptus grandis logs,"  BioRes. 12(3), 5790-5800.AbstractPDF

    The potential energy balance of the sawing logs for Eucalyptus lumber production was determined. Eucalyptus grandis logs (n = 10) were sawn with a band saw, and the planks were re-sawed with a circular saw. The sawing yield was calculated with the volumes of logs, lumbers, and wastes. The consumption of electric energy was measured using a multifunctional meter. The energy stored in the wood was determined by the lower calorific value of wood; the superior calorific value was calculated and converted into the respective active energy (kWh) value. The potential energy balance was calculated using the values of the consumed electricity in the saws and that of the energy stored in the waste. Another energy balance was calculated by considering the energy stored in the timber. The potential energy balance for sawing 1 m³ of log was equal to 1,206 kWh, considering only the energy stored in the waste. When added to energy stored in the timber, the energy balance was 2,671 kWh. The positive results of energy balances demonstrate the potential of energetic self-sufficiency of timber production.

  • Researchpp 5801-5811Karina, M., Syampurwadi, A., Satoto, R., Irmawati, Y., and Puspitasari, T. (2017). "Physical and mechanical properties of recycled polypropylene composites reinforced with rice straw lignin," BioRes. 12(3), 5801-5811.AbstractPDF

    Recycled polypropylene (RPP) and lignin represent by-products produced in enormous amounts worldwide that remain underutilized. This study used rice straw lignin as a filler at various concentrations (0% to 70% w/w) in RPP and virgin polypropylene (PP) composites by melt blending. Structural and morphological alterations of lignin were analyzed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. Mechanical properties were evaluated using a universal testing machine (UTM). Results revealed that the tensile strength of the composites decreased as the lignin content increased, presumably due to the low of compatibility degree of lignin and MAPP, as well as the crack formation due to the agglomeration of lignin. However, composites with lignin as a filler showed higher moduli and water absorption capacities, as well as thickness swelling; using lignin as a filler caused a drastic reduction of the elongation at break values. The results indicated that the physical and mechanical properties of RPP and its virgin PP composites had no substantial differences. This indicated that virgin PP could be substituted by recycled polypropylene (RPP) for composite applications with the addition of MAPP.

  • Researchpp 5812-5825Li, G., Sun, X., Lee, S., and Wu, Q. (2017). "Mechano-sorptive deformation of borate modified strand board for structural uses," BioRes. 12(3), 5812-5825.AbstractPDF

    Structural performance of chemically modified oriented strand board (OSB) has drawn great attention from builders, home insurance companies, and panel manufacturers. This study was conducted to provide time-dependent creep and moisture change-induced mechano-sorptive (MS) effect data from borate-treated and randomly formed strand board. The strand boards were lab-fabricated with flakes from southern yellow pine and mixed hardwoods. Commercial liquid phenol-formaldehyde resin was used as the binder. The treatments involved in the study were one level of zinc borate, one level of calcium borate, and two species groups that included separate controls. The load level, equivalent to 25% of the static bending modulus of rupture, was selected as a long-term constant load. Creep at 65% constant relative humidity (RH) developed in a normal time-dependent fashion and the Burger body creep model with four spring-dashpot elements was found appropriate to predict the creep response of borate modified strand board. Noticeable influence of borate modification on the fractional deflection was demonstrated under changing RH for both the absorption and desorption cycles. The measured fractional deflection due to the MS effect followed a linear relationship with moisture content change. The established material constants for various strand boards provided a way to predict the structural performance of treated strand board under varying RH conditions.

  • Researchpp 5826-5837Luo, X., and Wang, X. (2017). "Preparation and characterization of nanocellulose fibers from NaOH/Urea pretreatment of oil palm fibers," BioRes. 12(3), 5826-5837.AbstractPDF

    A facile method is reported to prepare nanocellulose fibers from oil palm trunk fibers. The fibers were pretreated 2 hours with NaOH/urea solution, and the fully swelled fibers were mechanically treated through high-pressure homogenization to obtain nanocellulose. The nanocellulose fibers were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). FTIR results revealed that there was no obvious difference between the spectra of the bleached fibers (BF), pretreated cellulose fibers (PCF), and cellulose nanofibers (NCF), which indicated that the pretreatment process is a non-derivative reaction. The crystallinity of PCF and NCF decreased and contained the cellulose I crystal structure. The PCF presented both a distorted structure and a coarser surface. The resulting NCF were approximately 10 nm to 100 nm in diameter with the length varying from hundreds of nanometers to several micrometers, as observed by SEM. The thermal degradation of NCF was 223 °C with about 20% weight loss, and the maximum degradation temperature was 338 °C. NaOH/urea showed potential as a mild solvent for preparing nanocellulose fibers.

  • Researchpp 5838-5850Lei, Y., Zhang, J., Chen, Z., Song, X., Huang, Z., and Xiao, J. (2017). "Mechanical properties of mulberry branch reconstituted square lumber," BioRes. 12(3), 5838-5850.AbstractPDF

    Reconstituted square lumber (RSL) was fabricated using mulberry branch as the raw material and polymeric diphenylmethane isocyanate (P-MDI) as the adhesive, and its mechanical properties were investigated. By using single factor and orthogonal experiments, the optimal parameters to produce RSL had 10% glue content, 160 °C hot-press temperature, and a 45 min hot-press time. The density distributions along with width, thickness, and length directions were scanned with DENSE-LAB X (density profile measuring system). Density was a significant factor that influenced the performances of mulberry branch RSL. The amount of glue also greatly affected the internal bond strength (IB), modulus of elasticity (MOE), modulus of rupture (MOR), and the 2-h thickness swelling rate of water absorption (TS2h) of RSL. Hot-press time affected the TS2h of RSL, but did not have a significant effect on the MOE, MOR, and IB of RSL. Hot-press temperature had an effect on the MOR of RSL, which significantly influenced the TS2h of RSL and slightly affected its MOE and IB. The density distribution of RSL was steep and flat in the width direction, steep in the thickness direction, and uniform in the length direction.

  • Researchpp 5851-5866Du, J., Xiong, C., Luo, B., Sun, Y., Tang, X., Zeng, X., Lei, T., Liu, S., and Lin, L. (2017). "Active oxygen and solid alkali pretreatment of bamboo residue: Features of hemicellulose during the cooking process," BioRes. 12(3), 5851-5866.AbstractPDF

    Bamboo residue was treated with an active oxygen (O2) and solid alkali (MgO) (CAOSA) process, which was developed recently by the authors owing to its environmentally friendly and high-efficiency characteristics. During the cooking process, 93.0% of lignin and 62.1% of hemicellulose were removed from the raw material, which resulted in a cellulose-rich pulp. This indicated that this cooking process is efficient to fractionate the bamboo residue into cellulose, hemicellulose, and lignin as a pretreatment for biomass conversion. The structural features of the hemicellulose from the pretreated bamboo residue were analyzed for comparison with that of the raw materials. The molecular structure of the hemicellulose fractions obtained from both the raw bamboo and pulp consisted of a (1→4)-β-D-Xylp backbone substituted with α-L-Araf and 4-O-methyl-α-D-glucuronic acid. The hemicellulose with more side chains tended to be more easily removed from the bamboo cell wall during the CAOSA process. Furthermore, the fractions of hemicellulose exhibited much lower thermal stabilities after the cooking process than the raw material.

  • Researchpp 5867-5877Bomba, J., Ježek, J., Hýsek, Š., Sikora, A., Stolariková, R., Palacká, A., Berková, M., and Kolbabová, T. (2017). "Polyurethane coatings on hardwood and softwood surfaces: Their resistance to household liquids as an educational case study," BioRes. 12(3), 5867-5877.AbstractPDF

    Effects of cold liquids on the cured film of selected coatings, the thickness of the final film coating on the resulting surface resistance, and different wood species on the resistance of the coating were investigated. It was demonstrated that different liquids affected the degradation of the cured film coating. The most aggressive liquid used was nail polish remover, followed by ethanol 40%, bleach, vinegar, and mouthwash. The least aggressive was dishwashing liquid. There was no evidence of a difference in the quality of the cured film coating applied on softwood and hardwood. The thickness of the coating had no statistically significant effect on the quality of the film. The liquids used for the tests are commonly used in households.

  • Researchpp 5878-5895Jumaat, S. R., Tajuddin, S. N., Sudmoon, R., Chaveerach, A., Abdullah, U. H., and Mohamed, R. (2017). "Chemical constituents and toxicity screening of three aromatic plant species from peninsular Malaysia," BioRes. 12(3), 5878-5895.AbstractPDF

    Medicinal and aromatic plants (MAPs) are widely valued for their aromas, tastes, and treatments for various human illnesses. The chemical constituents and toxicity content of three aromatic plant species, Syzygium polyanthum Wight (Walp.), Monocarpia marginalis (Scheff.) J. Sinclair, and Chromolaena odorata (L.) R.M. King & H. Rob, were determined, via gas chromatography (GC) with mass spectrometry (MS), and flame ionization detector (FID). Altogether, 116 compounds were identified in the essential oils and hexane and methanol extracts. Toxicity evaluations were carried out on human peripheral blood mononuclear cells (PBMCs). Three plant samples were found toxic to human PBMCs. The essential oils of M. marginalis and C. odorata, and the hexane extract of C. odorata yielded IC50 and LD50 values of 76 mg/mL and 6,913 mg/kg, 14 mg/mL and 3,684 mg/kg, and 2.45 mg/mL and 1,927 mg/kg, respectively. Based on the LD50 values, M. marginalis and C. odorata can be classified as slightly and moderately hazardous, respectively. A detailed toxicity evaluation via comet assay showed that M. marginalis and C. odorata induced significant DNA damage (p < 0.05). As for S. polyanthum, the species did not give any cytotoxic or genotoxic evidences.

  • Researchpp 5896-5912Moya, L., and Baño, V. (2017). "Elastic behavior of fast-growth Uruguayan pine determined from compression and bending tests," BioRes. 12(3), 5896-5912.AbstractPDF

    The design of engineered wood products and timber structures involving numerical simulations requires knowledge of the elastic and strength properties of wood. This study characterized the elastic behavior of Uruguayan pine wood (Pinus elliottii and P. taeda). A series of compression tests with the load applied with respect to various grain directions and bending tests were performed on small and clear specimens to determine the elastic constants and establish the relationships between the longitudinal moduli of elasticity obtained by the two testing methods. Moduli of elasticity, shear moduli, and Poisson ratios were determined. The longitudinal stiffness values in compression from the same specimen obtained by the two testing methods were similar. The moduli of elasticity in tension and compression parallel to the grain for the elastic behavior was obtained from experimental bending tests, and the downshift of the neutral axis until rupture was found. Using a model that simulates the post-elastic behavior as a curve comprised of several straight lines, the stress-strain diagram for tension and compression parallel to the grain was obtained.

  • Researchpp 5913-5927Faydi, Y., Brancheriau, L., Pot, G., and Collet, R. (2017). "Prediction of oak wood mechanical properties based on the statistical exploitation of vibrational response," BioRes. 12(3), 5913-5927.AbstractPDF

    In the European Union, timber is used in structural applications and must be graded with a Conformité Européene (CE) mark. To achieve standard, machine strength grading is used. A common technology for these machines is based on using the vibrational response of each wood board to estimate the timber modulus of elasticity and modulus of rupture. The first Eigen frequency is usually used to predict these mechanical properties. However, in heterogeneous wood species such as oak, this parameter is less correlated with mechanical properties. The current study proposes two new methods based on an extended exploitation of the vibrational response that predicts oak wood mechanical properties. The first method was based on the mechanical parameters deduced from several Eigen frequencies that were chosen with regards to a stepwise regression. The second method was based on the full vibrational spectrum and used a partial least squares method. The first method slightly improved the prediction of the modulus of elasticity compared with the first Eigen frequency in edgewise transversal vibration. Both methods significantly improved the prediction of the modulus of rupture.

  • Researchpp 5928-5941Chen, J., Zhang, L., Yang, G., Wang, Q., Li, R., and Lucia, L. A. (2017). "Preparation and characterization of activated carbon from hydrochar by phosphoric acid activation and its adsorption performance in prehydrolysis liquor," BioRes. 12(3), 5928-5941.AbstractPDF

    Hydrochar was used to produce activated carbon with high BET surface area and large pore volume via phosphoric acid activation. The hydrochar described here can be obtained from hydrothermal carbonization of corn cob residue (CCR). Porous structure of activated carbons was characterized by nitrogen adsorption and scanning electron microscopy (SEM). Results showed that the specific surface area and total pore volume of activated carbon were increased to 2192 m2/g and 1.269 cm3/g, respectively, under conditions of 400 °C, 1 h, and an impregnation ratio of 3, from 5.69 m2/g and 0.136 cm3/g of the starting material. The chemical properties of hydrochar and activated carbons were further characterized by Fourier transform infrared spectroscopy (FT-IR), which confirmed the chemical transformation. Furthermore, the localized graphitic nature of the porous carbon was shown by the X-ray diffraction pattern. Thus, the adsorption capacity was enhanced for activated carbon in comparison with commercial carbon. The process of activated carbon preparation provided a high value-added application of hydrochar.

  • Researchpp 5942-5952Andac, T., and Güzel, A. (2017). "Attitudes of families with children towards eco-friendly designed furniture: Kayseri sample," BioRes. 12(3), 5942-5952.AbstractPDF

    Eco-friendly products have played an important role across all aspects of human life. A wide range of eco-friendly furniture is in use. One of the purposes of this study is to investigate the general perspectives of parents from different demographic origins in terms of eco-friendly design and their tendency towards eco-friendly furniture. Another purpose is to examine the source of consciousness that has led to purchase and use of eco-friendly furniture in terms of parental influence. The data collected in this study were obtained through a questionnaire conducted at an independent furniture store in Kayseri. The hypotheses employed during the research were subjected to ANOVA testing and evaluated graphically with descriptive statistical methods. As a result of the questionnaire, it was detected that parents have an awareness of ecology. They are inclined to prefer furniture that is not harmful for health and environment. Especially, parents with a higher level of income tend to have a higher level of inclination. According to the analyses, despite the existence of eco-friendly furniture in the market, they are not widely preferred by parents due to high prices.

  • Researchpp 5953-5969Ordaz-Díaz, L. A., Valle-Cervantes, S., Rodríguez-Rosales, J., Bailón-Salas, A. M.,, Madrid-Del Palacio, M., Torres-Fraga, K., & De la Peña-Arellano, L. A. (2017). "Zeta potential as a tool to evaluate the optimum performance of a coagulation-flocculation process for wastewater internal treatment for recirculation in the pulp and paper process," BioRes. 12(3), 5953-5969.AbstractPDF

    The pulp and paper mill process requires large amounts of water. Therefore, the need to reuse water through the application of coagulation-flocculation processes, which is effective in the removal of solids and colloidal particles, has risen. In such processes, zeta potential (ZP) provides important information about the efficiency of the reagents used. The purpose of this study was to develop individual and combined tests of reagents to study turbidity and COD reduction based on ZP in the process of wastewater internal treatment for recirculation in the pulp and paper process. Factorial models were developed to explain the behavior of ZP depending on the different coagulants/flocculants. The statistical analyses showed that ZP had a positive correlation with parameters related to removal (COD and turbidity). It was demonstrated that innovate use of lentil extract (Lens esculenta) applied with aluminum sulfate favored the treatment, consistent with a coagulation-flocculation mechanism. The optimum doses of lentil extract were able to reduce the requirements of aluminum sulfate by almost 29%, providing an alternative strategy for water reuse processes in the pulp and paper industry.

  • Researchpp 5970-5983Wang, X., and Si, H. (2017). "Conveying characteristics of dual pneumatic feeder used for biomass pyrolysis," BioRes. 12(3), 5970-5983.AbstractPDF

    A novel dual pneumatic feeder was developed to achieve constant and steady biomass conveying for pyrolysis. To facilitate the feedstock replenishment, an injection pipe was installed inside a pressure chamber to convey the feedstock. Another stream of gas entered the pressure chamber from the bottom to fluidize the particles. Experiments were performed to test the performance of the new feeder, and three injection pipes and gas distributors were used. Results showed that the feeding rate depended on both the injection and fluidizing gas velocities. The feeding rate decreased with the inner diameter (ID) of an injection pipe, due to its impact on gas velocity, while the effective injection distance had a negative effect within a certain range. The opening ratio of the gas distributors had a positive effect on the feeding rate. Then, a model was developed, based on the Ergun equation, to describe relationships between the feeding rate and the gas velocities. The classical equation was further reformed to establish the correlation between the solid mass flowrate and the construction parameters of the feeder. The developed model deviated from the measured values within ± 15%, which was considered capable to predict the feeder performances.

  • Researchpp 5984-5995He, X., Xie, J., Xiong, X., Li, Y., Wei, Y., Quan, P., Mou, Q., and Li, X. (2017). "Study on dielectric properties of poplar wood over an ultra-wide frequency range," BioRes. 12(3), 5984-5995.AbstractPDF

    The dielectric properties of poplar wood (Populus deltoids cv. I-69/55) were measured using an Agilent network analyzer over the frequency range from 0.2 GHz to 20 GHz. The effects of moisture content, grain direction, temperature, and frequency on the dielectric constant and dielectric loss factor of wood were investigated. Regression equations were also established to predict the dielectric properties of wood having different grain directions and moisture contents. Results showed that the dielectric properties were strongly affected by the moisture content. As the moisture content increased from 0% to 100%, the dielectric constants of wood at longitudinal, radial, and tangential directions increased by 820.2%, 403.0%, and 434.0%, loss factors of wood at three directions increased by 8631%, 4949%, and 3404%, respectively. As frequency was increased, dielectric constant of wood decreased slowly; however, the loss factor decreased at the beginning and then increased. Dielectric properties of the wood also increased with increasing temperature. The dielectric constant in longitudinal directions was 1.2 times higher than the constant at tangential and radial directions, but the loss factor was 1.4 to 2.5 times higher. Regression equations were determined to fully describe the dielectric properties of wood at different grain dimensions and moisture contents.

  • Researchpp 5996-6010Abdul Khalil, H. P. S., Tye, Y. Y., Ismail, Z., Leong, J., Saurabh, C. K., Lai, T. K., Chong, E. W. N., Aditiawati, P., Tahir, P. M., and Dungani, R. (2017). "Oil palm shell nanofiller in seaweed-based composite film: Mechanical, physical, and morphological properties," BioRes. 12(3), 5996-6010.AbstractPDF

    Composite films that utilize seaweed as a matrix and oil palm shell (OPS) nanoparticles as a reinforcing material were developed. The effects of loading OPS nanoparticle (0%, 1%, 5%, 10%, 20%, and 30%) into seaweed films were determined by analyzing the physical, mechanical, and morphological properties of the films. The seaweed-based film incorporated with OPS nanoparticles at a high concentration (20% w/w) achieved the highest tensile strength (44.8 MPa) and Young’s Modulus (3.13 GPa). However, the film’s hydrophobicity (contact angle = 47.3º) and percentage of elongation at break (2.10%) were reduced. Moreover, it was observed that excessive loading of nanofillers (> 20%) reduced the tensile strength and hydrophilicity of the film. This phenomenon was attributed to the agglomeration of OPS nanoparticles and the formation of large voids on the film surface. Thus, the relative effectiveness of the various tested nanofiller contents in enhancing the mechanical strength of the composite film were found to be ranked in the following order: 20%, 10%, 5%, 30%, and 1%.

  • Researchpp 6011-6023Laskowska, A. (2017). "The influence of process parameters on the density profile and hardness of surface-densified birch wood (Betula pendula Roth)," BioRes. 12(3), 6011-6023.AbstractPDF

    This study examined the influence of temperature and time of treatment on the density profile and hardness of surface-densified birch wood (Betula pendula Roth). An analysis of the wood density profile was conducted on the basis of the following parameters: thickness, maximum density, and the distance between the maximum density and the wood surface. Depending on the technological parameters’ values, the degree of compression of the wood was 13% to 22%, and its maximum density was 808 kg/m3 to 994 kg/m3. As a result of the modification of birch wood at a temperature of 100 °C and 125 °C, the wood was densified on one side. As the temperature of the thermo-mechanical treatment was raised from 150 °C to 200 °C, the wood became densified on both sides. The maximum density of the wood increased gradually with the increase of the temperature of the press plate. The longer the time of thermo-mechanical treatment, the more distant the maximum density area was from the wood surface. Depending on the temperature and the time of treatment, the hardness of the surface-densified birch wood was 1.4 to 2.2 times greater than the hardness of non-densified wood.

  • Researchpp 6024-6039Liu, Z., He, T., Lan, Y., Yang, X., Meng, J., and Chen, W. (2017). "Maize stover biochar accelerated urea hydrolysis and short-term nitrogen turnover in soil," BioResources, 12(3), 6024-6039.AbstractPDF

    The study was carried to determine the labile carbon contents in biochar pyrolyzed under different temperatures and its effect on urea hydrolysis rate. Corn stovers were pyrolyzed at highest temperature of 300°C, 500°C and 700 °C to produce fresh biochar. Soil incubation experiment was conducted with biochar application rate of 0% and 2% with presence of urea. The results showed that biochars accelerated urea hydrolysis, and high temperature pyrolyzed biochar have more significant effect on soil pH enhances and acceleration of urea hydrolysis than biochar pyrolyzed at low temperature. Moreover, biochar produced at 300°C contains relative high concentration of labile carbon, and 43-64% of labile carbons were oxidized within 40 days incubation. The labile carbon in biochars also leaded microbes thrives and resulted in accelerate short-term N turnover. i.e. at early stage of incubation, fresh biochar increased mineralization of soil N by 79-449 mg•kg−1, and matured biochar by 30-61 mg•kg−1, but microbial immobilization effect was observed in fresh biochar-amended soil at the end of incubation. We concluded that aged biochar is suitable for simultaneous soil amendment with urea rather than newly produced biochar as it can promote available N accumulation in short time thus increase the risk of inorganic nitrogen leaching loss.

  • Researchpp 6040-6061Ramos-Carmona, S., and Pérez, J. (2017). "Effect of torrefied wood biomass under an oxidizing environment in a downdraft gasification process," BioRes. 12(3), 6040-6061.AbstractPDF

    The effect of composition and heating value of torrefied biomass under an oxidizing atmosphere at different conditions (180, 210, and 240 °C during 30, 75, and 120 minutes) was studied relative to downdraft gasification performance. An extended model for gasification in thermochemical equilibrium was used to evaluate the effect of pretreated biomasses, fuel-to-air equivalence ratio, and char byproduct production on the producer gas composition, reaction temperature, cold gas efficiency (CGE), and the engine fuel quality (EFQ). The model was validated with experimental data, reaching a global relative error of 8.5%. For raw or torrefied biomasses, with regard to char production, the CGE decreases if char increases; this is due to the fact that the process tends to combustion regimes when a lower amount of carbon is involved in the gasification reaction. Otherwise, the CGE and EFQ increase (up to 80% and 2.5 MJ/kg, respectively) if fuel-to-air ratio increases. With regard to the torrefied biomass, it is highlighted that CGE and EFQ increase from 77% to 82% and from 2.2 MJ/kg to 2.5 MJ/kg, respectively, when the torrefaction conditions (temperature and/or time) increase. This behavior is related to the increase of the autothermal zones in the gasification process and due to the higher heating value of torrefied biomass.

  • Researchpp 6062-6081Zhang, L., Wan, J., Hu, Z., and Jiang, W. (2017). "Preparation and photocatalytic activity of TiO2-wrapped cotton nanofiber composite catalysts," BioRes. 12(3), 6062-6081.AbstractPDF

    A novel TiO2-wrapped nanofiber composite catalyst, which possessed a unique porous structure and mixed crystalline phase, was prepared by the combination of superficial sol–gel and post-calcination processes. By means of the superficial sol–gel process, TiO2 layers were deposited on the surface of each nanofiber-like cellulose fiber, and then the TiO2-wrapped nanofiber composite catalysts were calcined at different temperatures under a nitrogen atmosphere. With temperature increasing, the original cotton nanofiber composites were converted into porous carbon nanofiber catalysts wrapped by a TiO2 mixed crystalline phase, which was accompanied by a crystal transformation. The photocatalytic activity of the new catalysts was evaluated by the degradation of methylene blue (MB) under ultraviolet (UV) irradiation. The results demonstrated that the new catalysts had good photocatalytic ability, and the TNC-700 catalyst showed a superior photocatalytic ability compared with the other catalysts; the new catalysts had a unique porous structure, high specific surface area, and mixed crystalline phase. Additionally, the synergistic photocatalytic effect of the TiO2 and activated carbon nanofiber resulted in the efficient degradation of organic pollutants in water or air.

  • Researchpp 6082-6093Zhang, J., Liang, J., Du, G., Zhou, X., Wang, H., and Lei, H. (2017). "Development and characterization of a Bayberry tannin-based adhesive for particleboard," BioRes. 12(3), 6082-6093.AbstractPDF

    A renewable bio-based thermosetting adhesive named tannin-furanic-formaldehyde (TFF) resin was synthesized using natural raw materials from crops and forest, such as furfuryl alcohol and bayberry tannin. The thermal properties of the adhesives were studied using differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermal gravimetric analysis (TGA). The structure of the TFF resin was characterized by electrospray ionization mass spectrometry (ESI-MS) and Fourier transform infrared (FTIR) spectroscopy. The results indicated that TFF resin was easily prepared. Moreover, it showed an excellent modulus of elasticity (MOE) and thermal resistance. Moreover, the cross-linking reaction of bayberry tannin, furfuryl alcohol, and formaldehyde under acid condition was established.

  • Researchpp 6094-6108Yuan, M., Shi, H., Sun, Y., Niu, M., and Ping, Q. (2017). "Comparative study on the yield and characterization of hemicelluloses isolated with hydrothermal extract and catalyzed by acetic acid from acacia wood," BioRes. 12(3), 6094-6108.AbstractPDF

    To utilize hemicelluloses from biomass as a feedstock to produce various value-added products, the soluble hemicelluloses must be isolated from the liquid phase with a high yield and purity. In this study, acacia wood was extracted by hydrothermal treatment, catalyzed by acetic acid at 170 °C for different lengths of time, and then precipitated after concentration and mixing with ethanol. Acetic acid led to faster hydrolysis of hemicelluloses, a process that was confirmed by a larger amount of total saccharides than the controlled results. A yield of more than 90% oligosaccharides was achieved in the hydrolysate with 1% (w/w) acetic acid. The maximum precipitate yield obtained was reduced, but a faster increase was observed in the first 30 min at 170 °C depending on the utilization of acetic acid. Analysis of 13C nuclear magnetic resonance (13C NMR) confirmed that the side chains, such as arabinose linked on the xylan chain, were severely broken down, and more dissolved hemicelluloses bonded with lignin (LCC) were present in the precipitates with 1% (w/w) acetic acid. Based on gel permeation chromatography (GPC), a molecular weight of not less than 1900 is suggested when ethanol is used to precipitate the oligosaccharides from hydrolysate.

  • Researchpp 6109-6121Retulainen, E., and Keränen, J. (2017). "Changing quality of recycled fiber material – Part II. Characterization of the strength potential with fiber integrity value and its relationship with the strength properties of paper," BioRes. 12(3), 6109-6121.AbstractPDF

    A novel method was introduced to evaluate the quality of fiber material from paper for recycling. The new concept, fiber integrity value, its components, and its relationship with paper strength properties were examined in more detail. The effect of deinking and screening on fiber integrity value, and its component parameters was shown. The fiber integrity value is closely connected to the strength potential of the pulp. It was shown that when the bonding degree was also considered, there was very good correlation with the tensile strength, tensile stiffness, and compressive strength (SCT) values. The fiber integrity value concept can be determined based on data from in-line analyzers.

  • Researchpp 6122-6133Viguier, J., Marcon, B., Girardon, S., and Denaud, L. (2017). "Effect of forestry management and veneer defects Iientified by x-ray analysis on mechanical properties of laminated veneer lumber beams made of beech," BioRes. 12(3), 6122-6133.AbstractPDF

    Interest in the use of beech as a raw material in engineered wood products for structural purpose has increased in Europe, in particular laminated veneer lumber (LVL). Indeed, this kind of product has exhibited superior mechanical properties with a lower variability compared to solid wood. This study investigated the influence of the forestry management system (e.g., high forest versus coppice) and of the veneer defects (e.g., knots and joints) on the mechanical properties of beech laminated veneer lumber (LVL) beams. The research included the measurement of modulus of elasticity and bending strength of 40 LVL beams (50 x 50 x 1200 mm3). Bending strength and modulus of elasticity of beam made from high forest wood compared to coppice wood were respectively higher by 20% and 12%. The impact of natural and manufacturing-process defects on the bending strength was studied using an X-ray imaging system. Defects in the inner layer of LVL beams were detected via X-ray. The defects produced by the manufacturing process itself had an effect on the bending strength similar to the natural defects of wood.

  • Researchpp 6134-6141Li, H., Song, G., and Sun, H. (2017). "Variation of chemical constituents of Qinghai spruce in natural decay process, including furfural production," BioRes. 12(3), 6134-6141.AbstractPDF

    Chemical constituents of naturally decayed Qinghai spruce branches were analyzed in terms of holocellulose, lignin, and pentosan. The holocellulose content declined from 57.98% to 35.29% in one year. The rate of change may be related to weather conditions, i.e., the rate of variation was higher when the temperature was high and rainfall was abundant. The changes in lignin and pentosan relative content were completely different from holocellulose; they increased first and then decreased during the decay period. Compared with fresh raw materials, pentosan content (from 14.44% to 25.9%) was increased by 79.4% after four months decay. The highest yield of furfural (10.2%) prepared by a two-stage method from decayed Qinghai spruce branches was similar to the reported yield from corncobs.

  • Researchpp 6142-6156Chen, G., and He, B. (2017). "Stress-strain constitutive relation of OSB under axial loading: An experimental investigation," BioRes. 12(3), 6142-6156.AbstractPDF

    The objective of this study was to establish the stress-strain empirical mode of oriented strand board (OSB) with random surfaces and oriented core 0° pattern (R/0°/R). The OSB specimens were loaded along the longitudinal (0°), diagonal (45°), and transverse (90°) directions of plates. The loading direction had a significant effect on the behavior of OSB. The OSB in compression exhibited high non-linear elastic behavior up to failure, while it expressed linear behavior when loaded in tension. Four types of failure modes under compression were included: end cracks between flakes, central cracks between flakes, diagonal shear failure, and surface folding. Most of the specimens in tension failed in tensile failure suddenly without plastic deformation. A refined empirical model was suggested and found to be in good agreement with the experimental data. The results provided useful information for modeling various structures containing OSB.

  • Researchpp 6157-6172Zhang, X., Zhang, F., Cai, H., and Zhang, H. (2017). "A representative study of CO2 emissions and carbon intensity based on a case of a pulp and paper mill in China: Calculation and analysis," BioRes. 12(3), 6157-6172.AbstractPDF

    In 2017, a carbon emissions trading market will be launched nationwide by the China government. Calculating the enterprise carbon emissions is an important prerequisite and basis for trading. This paper discussed types of greenhouse gases, calculation boundaries and methods, energy consumption, carbon emissions, and intensity of a representative integrated pulp and paper mill in China based on China Guidance and Greenhouse Gas Protocol Tools. The results showed that there were 435,000 tonnes (t) of CO2 emissions from that mill in 2014 that did not contain emissions of biomass energy, which was 8 times higher than that of fossil energy. The pulp carbon intensity based on the mill was 0.230 t CO2/Adt, which accounted for 7.50% to 57.4% in other pulps’ based on the product. Intensity based on Gross Domestic Product (GDP) was 1.090 t CO2e/1000 USD and accounted for 56.8% intensity in the China paper industry. The intensity based on sales accounted for 52.6% in the first-class enterprise in the developed country. It also showed that intensity was influenced by the species of raw material, energy, and products, which provided the mill with measures for energy saving and emissions reduction to obtain the redundant carbon emissions in the trading.

  • Researchpp 6173-6186Wang, X., Song, K., and Ou, R. (2017). "Effects of carbon black and titanium dioxide on ultraviolet weathering of wood flour-HDPE/lumber composites using multi-phase Co-extrusion technology," BioRes. 12(3), 6173-6186.AbstractPDF

    A new type of wood-plastic/lumber composite (WPLC) was fabricated with laminated veneer lumber as a core, and the traditional wood-plastic composite (WPC) as a shell layer using multi-phase co-extrusion technology. This WPLC was used to manufacture a window frame, and the effects of inorganic pigments (carbon black (CB), titanium dioxide (TiO2), and their mixtures) on the decorative effect and ultraviolet (UV) weathering performance of the shell layer of the window frame were investigated. Weathering variables included UV irradiation duration and water spraying cycles for up to 6000 h. The surface color was analyzed by spectrophotometry during weathering. In addition, a scanning electron microscopy analysis and Fourier transform infrared spectroscopy analyzed the weathering properties of the WPLC shell layer. The results showed that (1) different decorative effects (white, grey, and black color) of the window frames were achieved by incorporating CB, TiO2, and their mixture; (2) the composites incorporated with CB and/or TiO2 exhibited less discoloration and fewer surface cracks; (3) the composites with CB and TiO2 showed a better photo-stability than those with a UV stabilizer (UV326). The overall color change (△E) of the composites incorporated with UV326, TiO2, and CB was 20.0, 11.7, and 10.8, respectively, after 3000 h of weathering; and (4) a combination of CB and TiO2 showed a synergistic effect on alleviating the photo-oxidation process of the WPC shell layers, which confirmed its UV-shielding effect.

  • Researchpp 6187-6206Oszust, K., Pawlik, A., Janusz, G., Ziemiński, K., Cyran, M., Siczek, A., Gryta, A., Bilińska-Wielgus, N., and Frąc, M. (2017). "Characterization and influence of a multi-enzymatic biopreparation for biogas yield enhancement," BioRes. 12(3), 6187-6206.AbstractPDF

    A multi-enzymatic biopreparation of Trichoderma atroviride G79/11 origin was characterized. The fungus showed relatively high cellulase production in a soybean flour-cellulose-lactose medium. Subsequently, based on its post-culture liquid, the biopreparation of the enzyme mixture was developed and characterized. The liquid form of the enzyme mixture reached 22 U cm-3 of cellulolytic activity and its lyophilisate exhibited 1.09 U cm-3 at pH 5.1 and 50 °C. The enzyme mixture was characterized by the following activities: xylanase, β-glucosidase, carboxymethyl cellulase, polygalactouronase, pectinesterase, amylase, lactase, and protease. A method for an efficient conditioning process of organic waste (fruit processing waste, dairy sewage sludge, corn silage, and grain broth) for biogas yield enhancement using the enzyme mixture was proposed. The enzyme mixture increased the efficacy of biogas production by 30% when the lyophilizate (0.5 mg g-1 d.m.) was applied prior to fermentation. A method for conducting the enzymatic conditioning process of organic waste using the enzyme mixture as a pretreatment was proposed. This was part of the optimization of the methane fermentation process to increase the biogas yield. Consequently, after application of the biopreparation, the efficiency of anaerobic digestion of organic waste was improved.

  • Researchpp 6207-6236Kazeem, M. O., Shah, U. K. M., Bahariddin, A. S., and Abdul Rahman, N. A. A. (2017). "Influence of high-pressure steam pretreatment on the structure of rice husk and enzymatic saccharification in a two-step system," BioRes. 12(3), 6207-6236.AbstractPDF

    This study aimed at developing an operational high-pressure steam pretreatment (HPSP) to effectively modify rice husk for enzymatic saccharification. The HPSP was performed at 160 to 200 °C under 0.3 to 2.8 MPa for 2 to 10 min. The efficiency of this method was based on the chemical composition, scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD) analyses. Optimum pretreatment conditions (200 °C, 1.85 MPa for 7 min), enzyme concentration at 30 FPU/g and temperature at 60 °C for 48 h of continuous saccharification effectively produced sugar (21.1 g/L = 0.422 g/g dry substrate) at a saccharification degree of 53.87%. Conducting a second-step enzymatic saccharification resulted in additional sugar production (7.9 g/L = 0.158 g/g substrate) and a 20.44% saccharification degree. In contrast, the two-step saccharification process (48 and 24 h) achieved optimal sugar yield of 0.581 g/g substrate and saccharification degree of 73.5%. Additionally, the process improved the yield of monomeric sugars of glucose (0.465 g/g), xylose (0.010 g/g), and cellobiose (0.063 g/g). Therefore, the combination of the high-pressure steam pretreatment with thermostable cellulase from Bacillus licheniformis 2D55 in a two-step enzymatic saccharification process is an economically viable method in rice husk bioprocessing for sugar production.

  • Researchpp 6237-6250Luo, L., Chen, T., Zhao, W., and Fan, M. (2017). "Hydrothermal doping of nitrogen in bamboo-based super activated carbon for hydrogen storage," BioRes. 12(3), 6237-6250.AbstractPDF

    N-doped microporous activated carbons were synthesized by hydrothermal doping with ammonia as the nitrogen precursor; the chemical, structural, and hydrogen storage properties of the developed activated carbons (ACs) were also examined. The results showed that this method is an effective way of preparing microporous activated carbons with high surface area. Both the surface areas and the N contents of ACs were increased after hydrothermal doping, and hence, the hydrogen storage capacities were improved. The hydrogen storage capacity of the N-doped ACs was 3.10 wt.% at 77 K and 1 bar, showing an enhancement factor of 1.13 and corresponding to the NAC with both highest surface area (3485 m2/g) and N content (2.2 wt.%). Statistical analysis showed that both the N content and surface area had positive contributions to the hydrogen storage, and it also could be predicted by the linear model from the N content and surface area. These results were among the best in hydrogen storage carbon materials, and the high hydrogen storage capacities were attributed to the high surface area.

  • Researchpp 6251-6261Chen, Q. Y., Ma, X. J., Li, J. G., Miao, Q. X., and Huang, L. L. (2017). "Effect of the utilization of electron beam irradiation on the reactivity of bamboo dissolving pulp," BioRes. 12(3), 6251-6261.AbstractPDF

    Electron beam irradiation (EBI) was used to improve the reactivity of bamboo dissolving pulp. An EBI treatment with a dose lower than 10 kGy showed that the Fock reactivity of the dissolving pulp noticeably increased from 69.5% to 98.3% with negligible cellulose losses.  However, when the irradiation dose was higher than 10 kGy, the Fock reactivity increased with an observable α-cellulose loss, which could result in the lower strength of end-products. The gradual increase of Fock reactivity has a good agreement with the reduction of the degree of polymerization (DP) of cellulose. This suggests that lowering the DP of cellulose could enhance cellulose reactivity. Later analyses confirmed that an EBI treatment creates fiber pores that facilitate a cellulose xanthation reaction. The EBI treatment could randomly destroy cellulose crystalline and amorphous regions. The results indicated that the reactivity improvement was due not only to the DP, but also due to the changes in the fiber morphology and cellulose structure caused by the EBI processing.

  • Researchpp 6262-6275Min, D., Wang, S. F., Chang, H. M., Jameel, H., and Lucia, L. (2017). "Molecular changes in corn stover lignin resulting from pretreatment chemistry," BioRes. 12(3), 6262-6275.AbstractPDF

    Lignin is an amorphous polymer that limits the enzymatic conversion of polysaccharides to fermentable sugars. Thus, a pretreatment that can enhance the accessibility of carbohydrates is a key step of successful biofuel conversion schemes. In this study, corn stover was fractioned into stem, cob, and leaf because their lignin is different. To elucidate the lignin changes, autohydrolysis, diluted acid, and alkali pretreatments were applied on the samples, followed by the isolation of cellulolytic enzyme lignin preparations. Alkaline nitrobenzene oxidation, 13C-Nuclear Magnetic Resonance (NMR), and 1H-13C heteronuclear single quantum coherence NMR were used to profile the lignin changes. The results indicated that corn stover lignin is a p-hydroxyphenyl-guaiacyl-syringyl-type lignin that incorporates p-coumarate and ferulate esters. The β-aryl-ether was the most abundant inter-unit linkage, followed by condensed linkages, e.g. pino-/syringaresinol, phenylcoumaran, and spirodienone. As for the non-pretreated samples, leaf lignin was more condensed than stem lignin and cob lignin. More lignin was removed by the alkali pretreatment due to more cleavage of β-aryl-ether linkages. As a comparison, more condensed linkages were generated by the acidic pretreatments. The decrease of the syringyl/guaiacyl ratio indicated that the residual lignin became more condensed and confirmed that guaiacyl and p-hydroxyphenyl units were more stable than syringyl units during the pretreatment.

  • Researchpp 6276-6282Ferreira, B. S., Silva, J., V. F., and de Campos, C. I. (2017). "Static bending strength of heat-treated and chromated copper arsenate-treated plywood," BioRes. 12(3), 6276-6282.AbstractPDF

    Plywood can be used in the furniture industry and in civil construction due to its structural strength. However, for long useful life in construction, especially in tropical countries, it needs to undergo treatments against xylophagous organisms. The most common preservative treatment is the chemical chromated copper arsenate (CCA); there are alternatives, such as heat treatment, that do not use chemicals. The objective of this work was to evaluate the mechanical resistance of CCA and heat-treated plywood prepared at three different temperatures (160 °C, 180 °C, and 200 °C). Pinus taeda plywood with seven veneers and phenol-formaldehyde adhesive was produced and subjected to the preservative treatments. The results showed that the CCA treatment reduced the mechanical strength of the panels, while the heat treatment did not. Heat treatment also decreased panel hygroscopicity, indicating a better dimensional stability.

  • Researchpp 6283-6297Yu, Y., Zhang, F., Zhu, S., and Li, H. (2017). "Effects of high-pressure treatment on poplar wood: Density profile, mechanical properties, strength potential index, and microstructure," BioRes. 12(3), 6283-6297.AbstractPDF

    The density profile, mechanical properties, strength potential index, and microstructure changes of hybrid poplar were investigated before and after high-pressure (HP) treatments. The results of density profile indicated that a high uniform density distribution was developed inside the pressurized wood samples. The mechanical properties results showed that the HP treatments significantly increased (P < 0.05) the modulus of elasticity (MOE), the modulus of rupture (MOR), and the Brinell hardness (BH) of the densified wood at selected conditions. Of all the wood samples, the compressed wood at 150 MPa condition possessed the highest density and strength properties. Considering the variation in strength properties along with density, it can be concluded that the compression destruction degree of HP treatment was comparable with that caused by optimized thermal compression technique based on the strength potential index results. The integrity of wood cells presented in scanning electron microscopy results demonstrated the compression of wood cell wall achieved by HP treatment without causing any fractures, which further indicated that HP treatment is a less destructive compression technology. Based on this research, HP treatment has great potential to be applied in wood densification for commercial use.

  • Researchpp 6298-6308Park, C. W., Han, S. Y., Choi, S. K., and Lee, S. H. (2017). "Preparation and properties of holocellulose nanofibrils with different hemicellulose content," BioRes. 12(3), 6298-6308.AbstractPDF

    The hemicellulose content in holocellulose was adjusted by an alkaline treatment. The effects of this treatment on the defibrillation efficiency of holocellulose nanofibrils (HCNFs) were investigated by wet disk-milling (WDM), along with their morphological and physical properties. In addition, the tensile properties of nanopaper sheets fabricated with these HCNFs were investigated. As the hemicellulose content decreased, the average diameter and the filtration time of the HCNFs decreased, whereas specific surface area and crystallinity index increased. An increase in the WDM time reduced the average diameter and crystallinity of the HCNFs and increased their filtration time and specific surface area. The tensile strength and elastic modulus of the nanopaper sheets increased with increased hemicellulose content and WMD time.

  • Researchpp 6309-6321Kim, T. Y., Kim, C. H., and Lee, H. L. (2017). "Effect of circulation time on the physical properties of currency," BioRes. 12(3), 6309-6321.AbstractPDF

    Durability is a very important property of currency and currency paper because currency is circulated in the public for a very long time. The effect of circulation time on the physical properties of currency was investigated. In addition, a crumpling treatment procedure was adopted to simulate the circulation of currency in public. The air permeance of currency that was subjected to eight rounds of crumpling treatment was compared with that of actual circulated currency. As the circulation time increased, the basis weight, thickness, air permeance, and b* value increased. On the other hand, the stiffness and the L* value decreased as the circulation time increased. Regarding the air permeance, the slope of the plot was greater than the slopes of other physical properties measured. Air permeance of the samples after the crumpling treatment was greater than that of the circulated currency, which indicated that the crumpling process resulted in more severe changes in air permeance than the crumpling that occurs during the actual circulation of currency.

  • Researchpp 6322-6341Zhu, D., Yang, H., Chen, Y., Li, Z., Wang, X.,  and Chen, H. (2017). "Fouling and slagging characteristics during co-combustion of coal and biomass," BioRes. 12(3), 6322-6341.AbstractPDF

    The effects of different kinds (cotton stalk, rice husk, and sawdust) and proportions (0%, 10%, 20%, and 30% based on weight) of biomass and operating conditions (temperature and excess air coefficient) were evaluated relative to the ash deposition characteristics during the co-firing of Huang Ling (HL) coal with biomass. The experiments were performed in a drop-tube furnace. The chemical compositions and mineral phase characteristics of the collected ash particles were analyzed using scanning electron microscopy with energy dispersive X-ray (SEM-EDX) and X-ray diffraction (XRD), respectively. The results showed that the most severe agglomeration, from co-firing coal with cotton stalk, was due to the higher content of alkali metals, especially K. The amount of K in the ash increased with an increasing proportion of cotton stalk, and ultimately, agglomeration was more serious. When the combustion temperature increased from 1050 °C to 1300 °C, the dystectic solid compounds were transformed into eutectic compounds. The increased excess air coefficient accelerated the sulfur reaction, but did not relieve the heavy sintering. Consequently, limiting the content of biomass in the fuel blends, maintaining a lower combustion temperature, and a suitable level of excess air were determined to be necessary for the co-firing of coal and biomass.

  • Researchpp 6342-6352Yang, H., Wang, K., Ma, J., Yang, J., and Shi, Z. (2017). "Liquid hot water pretreatment of wheat straw for full carbohydrates biorefinery," BioRes. 12(3), 6342-6352.AbstractPDF

    Liquid hot water (LHW) and alkali-promoted LHW pretreatments of wheat straw were comparatively studied at temperatures from 100 °C to 180 °C to investigate their ethanol production and pentose recovery. An amount of 4.52 g/L ethanol was obtained by fermentation from the synergistic substrate treated with LHW under optimal temperature (140 ºC) and enzymatic hydrolysis (EH). Under these conditions, the recovery rate of pentose was 48.8% and 58.1% for xylose and arabinose, respectively. After the pretreatment and bioconversion processes, 20.3% cellulose, 10.5% xylan, and 19.5% lignin remained solid. The alkali promoter introduced into LHW enhanced the bioconversion efficiency of the substrate, which resulted in 5.82 g/L ethanol, and 57.5% xylose and 59.0% arabinose recovery, respectively. The results from this study contributed an effective manner for co-production of ethanol and pentose, enlarging the utilization efficiency of carbohydrates.

  • Researchpp 6353-6365Lu, H., Zhang, X., Wu, A., Deng, X., Ren, J., Kong, F., and Li, H. (2017). "Comparison of dilute acid, alkali, and biological pretreatments for reducing sugar production from eucalyptus," BioRes. 12(3), 6353-6365.AbstractPDF

    The effects of chemical pretreatments (dilute H2SO4, dilute NaOH, and NH4OH) and biological pretreatments (Coriolus versicolor and Daedalea quercina) on the enzymatic hydrolysis of Eucalyptus were investigated. The results showed that Eucalyptus obtained from different regions possess similar chemical compositions and that the optimum particle sizes for reducing sugar production were 60- to 80-mesh. Contrary to the negative influences of a dilute H2SO4 pretreatment, an alkali pretreatment showed positive effects on Eucalyptus saccharification. This phenomenon may had been attributed to the efficient removal of lignin and the stronger structural damage during the alkali pretreatment process. In comparison with the chemical pretreatments, a higher reducing sugar yield could be achieved from the biological pretreated Eucalyptus. The highest reducing sugar yield of 97.14 mg/g was obtained from the Guangxi (GX) Eucalyptus that was pretreated with Daedalea quercina.

  • Researchpp 6366-6377Cao, T., Chen, W., Yang, T., He, T., Liu, Z., and Meng, J. (2017). "Surface characterization of aged biochar incubated in different types of soil," BioRes. 12(3), 6366-6377.AbstractPDF

    The aim of this study was to investigate the changes that occur in the molecular form and surface morphology of aged biochar and to explore the dynamics of aging in various types of soil. For this purpose, the biochar was rice hull heated to 500 °C for 30 min. Approximately 15% of fresh biochar was incubated in either acidic red soil, weak alkaline sandy soil, or alkaline coastal solonchak for 1 and 13 months. Aged biochars incubated without soil were also prepared. The characteristics of fresh biochar and aged biochar were analyzed in terms of elemental composition, specific surface area, and pore size, together with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results for aged biochar relative to fresh biochar included: (1) decreased carbon and nitrogen contents; (2) reduced pH values which tended to be neutral; (3) reduced porosity and specific surface area (Brunauer-Emmett-Teller, BET), depending on incubation environment; and (4) increased oxygen-containing functional groups on the surface. In general, the surface characteristics of the aged biochar were changed and varied with soil type.

  • Researchpp 6378-6391Chen, C., Wang, C., Xu, H., and Dai, H. (2017). "Aggregation process and mechanism of pitch deposits with Ca2+ in papermaking white water," BioRes. 12(3), 6378-6391.AbstractPDF

    The lipophilic colloidal substances (CS) in papermaking white water mainly originate from sizing agents applied during paper manufacturing operations and wood extractives, such as resin acids and fatty acids. In this study, the aqueous dispersions of sodium resinate and sodium stearate were used to simulate the colloidal substances concentrated in white water. The aggregation process and mechanism of pitch deposits developed from soluble colloidal particles were investigated by the determination of turbidity and zeta potential of colloidal substances simulacra dispersions as a function of Ca2+ concentration, as well as through morphological observation, structural characterization, and contact angle measurement of calcium-induced pitch deposits. The results showed that the micelles with hydrophilic groups extending in the water could be formed when the colloidal substances accumulated to a certain concentration. The Ca2+ can exchange Na+ of colloidal substance micelles, and hydrophobic pitch deposits can then be produced by either particle-particle collision or “layer by layer” adsorption with addition of Ca2+, or by both of the mechanisms mentioned above. The complete destabilization of the colloidal substance simulacra occurred when the Ca2+ concentration reached 5 mmol/L. The initial contact angles of water on the surfaces of calcium resinate and calcium stearate discs were 90.2° and 96.0°, respectively.

  • Researchpp 6392-6404Flores-Hernández, M. A., Torres-Rendón, J. G., Jiménez-Amezcua, R. M., Lomelí-Ramírez, M. G., Fuentes-Talavera, F. J., Silva-Guzmán, J. A., and García Enriquez, S. (2017). "Studies on mechanical performance of wood-plastic composites: Polystyrene-Eucalyptus globulus Labill," BioRes. 12(3), 6392-6404.AbstractPDF

    The effects of size and concentration of wood particles on the properties of composites, obtained by extrusion, were evaluated based on polystyrene and wood particles from Eucalyptus globulus Labill. Wood-plastic ratios were 10:90, 30:70, and 50:50 (weight / weight), and wood particles were retained in 40, 50, 65, and 100-mesh sieves. The density, flow index, water absorption, and the mechanical properties were evaluated. Scanning electron microscopy revealed poor adhesion between the wood particles and the polystyrene. The size and content of wood particles were found to have a strong influence on the mechanical properties of the composite. The introduction of the wood particles induced a reduction of the Young’s modulus, ultimate strength and deflection, as well as an increment in the elongation at break. The impact resistance also increased with the size and concentration of the wood particles. Furthermore, with increasing content of wood particles, the value of the melt flow index decreased and the water absorption rose.

  • Researchpp 6405-6417Xu, M., Xing, L., Zhang, Q., and Pu, J. (2017). "Ultrasonic-assisted method of graphite preparation from wheat straw," BioRes. 12(3), 6405-6417.AbstractPDF

    Graphite production was achieved unexpectedly in the course of demonstrating a new ultrasonic-assisted wheat straw pulping method at room temperature and at atmospheric pressure. The graphite material was found in the ultrasonic-assisted pulp (UP) ash, as shown by X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and TEM analysis. UP ash contained both inorganic and organic components. The total content of inorganic components in the ash was 81.9%, while the content of organic component (graphite material) was 18.1%. The graphite content in the pulp was calculated to be approximately 4.5%. This work describes a new meaningful approach for the facile preparation of graphite materials. The graphitization was based on the ultrasonic cavitation mechanism of extreme condition, while the process would be divided into three steps, degradation of lignin, graphene formation, and graphitization process.

  • Researchpp 6418-6426Lee, M., Jang, J., Lee, S., and Park, S. (2017). "Effect of loess treatment and carbonization on the hygric performance of medium-density fiberboard," BioRes. 12(3), 6418-6426.AbstractPDF

    The level of relative humidity is one of the key parameters in evaluating indoor air quality and comfort. In principle, humidity can be kept more uniform over time by use of materials that adsorb moisture from the air reversibly. This study was conducted to investigate the effect of loess treatment and carbonization on the hygric performance of medium-density fiberboard (MDF). The loess treatment was conducted with different sizes of loess particle prepared by a high-pressure homogenizer. After loess treatment on the surface of the MDF, it was carbonized at high temperature (600 °C). Loess is an abundant mineral high in Si content, which has high moisture absorption capacity, which remained after the carbonization process. The study also found that the loess treatment positively affected the hygric performance of carbonized MDF (c-MDF). The hygric performance of c-MDF almost doubled after the loess treatment compared with the non-treated c-MDF. However, the nano conversion of loess did not influence the hygric performance. Loess-treated carbonized MDF could be used as a humidity controller in buildings.

  • Researchpp 6427-6433Lee, M., Jang, J., Lee, S., and Park, S. (2017). "Comparison of the radon absorption capacity of carbonized boards from different wood-based panels," BioRes. 12(3), 6427-6433.AbstractPDF

    The radon absorption performance was determined and compared for different types of carbonized boards to establish effective carbonized boards. Moreover, the absorption mechanism of carbonized boards was investigated by specific surface area and pore size in each of the carbonized boards. The radon absorption performance was ranked in the following order: ash (87%), medium-density fiberboard (MDF, 83%), oriented strand board (OSB, 82%), particleboard (PB, 77%), and plywood (PW, 67%). The correlation between radon absorption capacity and surface area or pore volume showed that a higher surface area or pore volume had higher radon absorption performance. However, the highest surface area and pore volume was detected on carbonized MDF, which had a radon absorption performance that was 5% less than carbonized ash board. Therefore, the surface area and pore volume as well as other factors affected the absorption performance.

  • Researchpp 6434-6445Hou, Y., Yan, S., Guo, X., and Di, M. (2017). "Combined surface treatment of polyethylene wood-plastic composites to achieve rapid bonding with desired adhesion properties," BioRes. 12(3), 6434-6445.AbstractPDF

    To achieve rapid bonding with desired adhesion properties, a combined treatment of sanding then coating with polyisocyanate, followed by plasma discharge was implemented on the surfaces of polyethylene wood-plastic composites (WPCs). The surface properties of polyethylene WPCs were studied by evaluating the contact angle and bonding strength, as well as analyzing it via Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The results indicated that the shear strength and durability of the bonding joints of polyethylene WPCs increased considerably due to the synergetic effect from the surface treatment. Thus, a rapid bonding with desired adhesion properties of polyethylene WPCs was achieved. The roughness and the oxygen content on the composites’ surface increased after the combined treatment. Polar functional groups, such as –OH, –C=O, and –O–C=O, formed on the surface. At the same time, the presence of –NCO and –NH functionalities, generated during the combined treatment, showed that chemical bondings between polyisocyanate and the wood fibers of the composites occurred. The changes on the surface properties, such as roughness, wettability, as well as formation of chemical groups, substantially affected the adhesion properties of the bonding joint for polyethylene WPCs.

  • Researchpp 6446-6457Zhang, H., Pizzi, A., Lu, X., and Wang, Z. (2017). "Study of the end-grain butt joints obtained by friction welding of moso bamboo," BioRes. 12(3), 6446-6457.AbstractPDF

    End-grain-to-end-grain welding has been the object of considerable study in the authors’ laboratory, but successful experiments have been hindered by wood defibration. End-grain butt joints obtained by friction welding with moso bamboo showed relatively good experimental results compared to beech, oak, and spruce. The average compression shear strength of the welded joints reached 5.81 MPa, and the departure of the bamboo fibers could not be observed during the welding process. A study of the microstructure of the welded surface revealed that during the welding process, hard vascular bundles within the fibers became prominent on the welded surface and acted similarly to a brush. These bundles dissipated lateral friction and protected the bamboo from cracking in the process.

  • Researchpp 6458-6470Cichy, W., Witczak, M., and Walkowiak, M. (2017). "Fuel properties of woody biomass from pruning operations in fruit orchards," BioRes. 12(3), 6458-6470.AbstractPDF

    Biomass has become a major source of renewable energy. The basic fuel properties of woody biomass from orchards were evaluated on the following fruit tree wood obtained from pruning operations: ‘Reliance’ peach, ‘Burlat’ cherry, ‘Packham’s Triumph’ pear, ‘Early Geneva’ apple, hazel (Polish variety Halle), ‘Hargrand’ apricot, walnut, domestic plum (Polish variety Węgierka), and sour cherry (variety Ujfehertoi fürtos). The research included the wood and bark of the trunk, whole limbs, and branches. Gross calorific value for the majority tested biomass ranged from 19.2 to 21.3 MJ / kg, which is typical for wood and bark of broadleaf species. The low content of chlorine and sulfur in the analyzed samples would contribute to low corrosion in boilers and a low atmospheric pollution factor for generated sulfur oxides and hydrogen chloride. Properties of fuel biomass obtained from pruning operations were not noticeably different from the typical properties of solid biofuels derived from woody forest biomass. Based on these results, biomass from orchards can be a substitute for raw forest material suitable for energy use.

  • Researchpp 6471-6489Rosero-Alvarado, J., Hernández, R., and Riedl, B. (2017). "Effects of fire-retardant treatment and burl wood structure on three-dimensional changes of sandwich panels made from walnut decorative veneer," BioRes. 12(3), 6471-6489.AbstractPDF

    The effects of a fire-retardant treatment and burl wood structure on the three-dimensional changes of aircraft sandwich panels were evaluated. Unvarnished and varnished panels with an outer decorative layer made from walnut burl (Juglans hindsii L.) were studied. Half of the samples from each type of panel received a fire-retardant treatment (phosphate-based) on all three layers of the decorative plywood. The other half had the two inner layers treated and the outer layer was left untreated. Three different wood areas formed by rotary peeling and by the grain orientation from the burl structure were identified and their veneer surfaces were separately studied. Samples pre-conditioned at 20 °C and 40% relative humidity (RH) underwent adsorption (25 °C, 90% RH) and then desorption (25 °C, 40% RH) treatments. Changes in the moisture content (MC), swelling, shrinkage, roughness, and waviness were measured after each moisture exposure condition. The results showed that the fire-retardant treatment significantly increased the MC, swelling, shrinkage, roughness, and waviness of the unvarnished and varnished panels. This treatment also affected the roughness and waviness of the burl wood structure for the unvarnished panels. The effect of this anatomical feature was not noticeable in the varnished panels.

  • Researchpp 6490-6503Skrobot III, F., Diehl, S. V., and Borazjani, H. (2017). "Mycotoxin production by Stachybotrys chartarum on water-damaged building materials," BioRes. 12(3), 6490-6503.AbstractPDF

    The major question after a flooding event is whether to remove or remediate the building materials so that potentially harmful mold growth and their by-products cannot cause serious health problems for susceptible individuals. The purpose of this study was to determine the growth of Stachybotrys chartarum and corresponding production of macrocyclic trichothecenes on different components of a residential wall up to 65 days after a simulated flood event. Small-scale residential walls constructed of fiberglass batt insulation, oriented strandboard, gypsum wallboard, and lumber were destructively sampled at four time points. All four building materials contained notable levels of macrocyclic trichothecenes on all collection days. The highest concentrations of macrocyclic trichothecenes were on the paper siding of the gypsum wallboard, followed by the paper siding of the batt insulation and wood lumber. There was a significant increase in trichothecene concentration over time, particularly on the gypsum. The DNA concentrations of the mold were significantly higher on the batt insulation than on the wood products, and the mold concentrations also increased over time on the batt insulation and gypsum, but not on the wood products. It was concluded that if a flooding event should occur, the insulation and gypsum should be removed from the home and the remaining materials should be remediated.

  • Researchpp 6504-6517Park, Y. C., Yoon, J. J., Kim, S. H., Kim, T. H., and Kim, J. S. (2017). "Two-stage flow-through pretreatment of Helianthus tuberosus residue for enzymatic production of fermentable sugar by alkaline and acidic solutions," BioRes. 12(3), 6504-6517.AbstractPDF

    A response surface methodology (RSM) tool with the Box-Behnken design was used to determine the optimum pretreatment conditions of Helianthus tuberosus residue for the enzymatic production of fermentable sugar with aqueous ammonia and sulfuric acid solutions, for various parameters such as pretreatment solution concentration, temperature, and reaction time. The pretreatment of biomass was performed using these optimized parameters in aqueous ammonia and sulfuric acid solution, followed by hot water, under the same conditions. The process was then performed by changing the sequence.

  • Researchpp 6518-6528Kiaei, M., Kord, B., Samariha, A., Rastegar Moghdam, Y., and Farsi, M. (2017). "Mechanical, flammability, and morphological properties of nano-composite plastic based on hardwood flour high-density polyethylene embedding by nano-zinc oxide," BioRes. 12(3), 6518-6528.AbstractPDF

    The influence of the nano-zinc oxide amount was evaluated relative to the flammability behavior, as well as the morphological and mechanical properties of wood plastic composites (WPCs). The polymer amount was approximately 50 wt%, and the lignocellulose material was 50 wt%. Nano-zinc oxide was applied at six weight levels including, zero (control), 1, 2, 3, 4, and 5 phc. For all treatments, the maleic anhydride polyethylene (MAPE) amount was 2 phc. The WPCs were made using a mixture of nano zinc oxide, high-density polyethylene, and mixed hardwood flour injection molding method. The morphological and mechanical properties, such as flexural strength and modulus, were measured. Various tests were conducted with a cone calorimeter, including the amount of char residue, total smoke production, time to ignition, and heat release rate, according to ASTM E1354-92 (1992). The flexural strength and modulus of composites in samples with 5 phc nano-zinc oxide were 79.9% and 27.2% greater, respectively, than in samples without nano zinc oxide. Nano-zinc oxide enhancement to 5 phc increased the ignition time and char residue 105.1% and 121.7%, respectively, and decreased the burning rate and total amount of smoke production 20.3% and 46.0%, respectively. Scanning electron microscope results indicated the presence of nano-zinc oxide agglomerates in the sample.

  • Researchpp 6529-6544Yue, Y., Lin, Q., Irfan, M., Chen, Q., Zhao, X., and Li, G. (2017). "Characteristics and potential values of bio-products derived from switchgrass grown in a saline soil using a fixed-bed slow pyrolysis system," BioRes. 12(3), 6529-6544.AbstractPDF

    Switchgrass harvested from saline soil was slowly pyrolyzed at 300, 500, and 700 °C in a fixed-bed reactor. The objective was to understand the characteristics and evaluate the potential values of the bio-oil, syngas, and biochar. The biochar yield (27.0% to 41.3%) decreased with increasing temperature, whereas the syngas yield (26.3% to 40.9%) increased. The bio-oil yield (30.8% to 34.1%) was highest when the switchgrass was pyrolyzed at 500 °C. Both the bio-oil and syngas had low value as direct fuels because of their low heating values. Compared with the biochars from the switchgrass grown in “sweet” soil, the biochars derived from the switchgrass grown in saline soil had higher values of ash (10.5% to 17.2%), mineral nutrients, and cation exchange capacity (CEC) (200.3 to 241.1 cmol/kg). These results suggested that the biochar generated in this study might have a better liming effect and improvement of soil fertility and crop growth as a soil conditioner, and lead to double wins in saline soil improvement and a new approach for switchgrass utilization.

  • Researchpp 6545-6557Liu, F., Chen, Y., and Gao, J. (2017). "Preparation and characterization of biobased graphene from kraft lignin," BioRes. 12(3), 6545-6557.AbstractPDF

    Graphene was manufactured from commercial kraft lignin, and its forming mechanism, structure, and properties were investigated. A single factor test was employed to determine the optimum conditions of the production of graphene nanosheets. Kraft lignin was mixed with iron powders as catalyst with different weight ratios. The mixed carbon source and catalyst were thermally treated at 1000 °C and incubated for a period of time in a tubular furnace. The thermally treated carbon materials were analyzed by field emission scanning electron microscopy (FE-SEM), Raman spectroscopy, atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The preferable conditions for production of graphene nanosheets from kraft lignin were determined. The graphene fold structure was obtained after thermally treating for 90 min when the ratio of carbon source to iron was 3:1. The results revealed that folded lamellar graphene structure increased with greater holding time. Carbon nanotubes (CNTs) were observed after thermal treatment for 105 min. These results indicate the formation of graphite crystal structure and multi-layered graphene from kraft lignin in the presence of iron catalyst.

  • Researchpp 6558-6567Xavier, C. R., López, D., Gómez, G., Chamorro, S., Scholze, A., and Vidal, G. (2017). "Sensitivity study comparing Daphnia obtusa (Kurz 1874) and Daphnia magna (Straus 1820) exposure to treated kraft mill effluents, diethylstilbestrol, and androstenedione," BioRes. 12(3), 6558-6567.AbstractPDF

    Kraft mill effluents treated by activated sludge show a reduction in acute toxicity. However, their discharges produce hormonal effects in an aquatic ecosystem, due to the sterols metabolites as androstenedione contained in the effluents. Daphnids bioassays are a powerful approach for determining toxicity. However, there are relative sensitivities depending on the species. The main objective of this study is to determine the sensitivity of D. magna and D. obtusa when exposed to kraft mill effluents, diethylstilboestrol (DES), and androstenedione (AED). The sensitivities were tested using acute bioassay exposed to kraft pulp mill. Moreover, the allometric growth rate of both daphnids affected by DES and AED regarding time were also evaluated for a period of nine days. Variation in the ratio between body length and body width – at the abdominal cavity – over time (k index) was evaluated. Results indicated that AED and DES compounds affected the allometric growth rate of daphnids. Specifically D. magna exhibited more sensitivity when it was exposed to kraft pulp mill.

  • Researchpp 6568-6578Chen, F., Li, H., Jiang, Z., and Wang, G. (2017). "Effects of aging temperature on mechanical performance of bamboo bundle laminated veneer lumber joints prepared by intermittent hot press process," BioRes. 12(3), 6568-6578.AbstractPDF

    Recently, an intermittent hot-pressing process had been developed and applied to produce bamboo bundle laminated veneer lumber (BLVL) joints with lengths of more than 6 m. According to our previous studies, there was a major difference in the physical and mechanical performance of hot-pressing joints and at adjacent positions on the lumber. In this paper, heat transfer and the effects of various aging temperatures on the mechanical performance of the joints of intermittent hot-pressed BLVLs were studied. During the hot-pressing process, there were noticeable different temperature changes on the board. In addition, degradation of the modulus of elasticity (MOE) and modulus of rupture (MOR) values on the joints was greater than that on the adjacent positions of the BLVLs, and the degradation increased with increasing aging temperature. Because of the low interfacial bonding strength of the joints caused by the pre-curing effect during the hot-pressing process, the MOR was more sensitive to hydrothermal conditions. Therefore, when BLVLs produced by intermittent hot-pressing are used as engineering components, the joints should be well-designed and arranged to avoid being used in the same cross-section.

  • Researchpp 6579-6590Almeida, T. H. de., Almeida, D. H. de., De Araujo, V. A., Silva, S. A. M., Christoforo, A. L., and Lahr, F. A. R. (2017). "Density as estimator of dimensional stability quantities of Brazilian tropical woods," BioRes. 12(3), 6579-6590.AbstractPDF

    Wood is a material widely used in various sectors of construction, such as in structures and building components. The volume of wood extracted from tropical forests has reached a considerable amount, and this wood is marketed with popular names without prior characterization. Wood density is an easy property to measure, and its use as an estimator of other properties is very common in this sector. This study investigated the possibility of the estimation of important quantities in dimensional stability of Brazilian tropical woods by using the density at 12% moisture content, anhydrous density, and basic density. Testing the ability to estimate radial, axial, tangential, and volumetric shrinkage, anisotropy coefficient, coefficient of volumetric rate of volumetric shrinkage, as well as the rate of volumetric swelling using the densities above, with linear, exponential, geometric, and logarithmic models, the best determination coefficient was: R2 = 19.58%. The results were, in summary, that the variable density was not a good estimator of the dimensional stability of the wood.

  • Researchpp 6591-6606Lan, Y., Yan, N., and Wang, W. (2017). "Polydimethylsiloxane (PDMS) membrane filled with biochar core-shell particles for removing ethanol from water," BioRes. 12(3), 6591-6606.AbstractPDF

    A new type of biochar-SiO2 core-shell particles (BCNPs) was successfully prepared via the sol-gel-sediment method. The characteristics of BCNPs were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). This novel filler was added to a polydimethylsiloxane (PDMS) matrix to prepare composite membranes to separate ethanol from water via pervaporation (PV). The effect of BCNPs on the performance of the membranes was researched. Experimental results showed that the addition of BCNPs led to remarkably improved PV performance of composite membranes. When a BCNPs content was 5 wt.% for a 10 wt.% ethanol solution at 40 °C, the best PV performances gained were the separation factor of 11.9 and the corresponding permeation flux of 227 g·m-2·h-1.

  • Researchpp 6607-6617Qian, S., Zhang, F., Liu, B., Ren, H., and Tong, G. (2017). "Polyacrylate-based water-absorbent hydrogels prepared with lignin-related compounds: Process conditions and performance," BioRes. 12(3), 6607-6617.AbstractPDF

    Utilizing biomass resources to synthesize water-absorbent resin has attracted global interest as a new research direction. Lignin, as the second most abundant renewable biopolymer in nature, is a strong candidate for use in renewable materials. In this study, water-absorbent resins were synthesized from lignosulfonate (LS) and acrylic acid (AA) by grafting copolymerization with an aqueous solution of potassium persulfate (KPS) as the initiator and N’N-methylene-bis-acrylamide (MBA) as a crosslinking agent. The optimum process parameters of lignosulfonate-grafted-polyacrylic acid resin (LS-PAA) were obtained via a single-factor method: AA 30 wt.%, LS 2.67 wt.% (to AA), cross-linker 0.03 wt.% (to AA), initiator 0.43 wt.% (to AA), and neutralization 65%. The optimum reaction temperature was 60 °C. Although lignin is a hydrophobic polymer, it has many reactive functional groups that can react with AA. It has been expected that adding lignins can change the cross-linking density by their three-dimensional structure, thus increasing the water absorbency. The LS-PAA resins were compared to other kinds of lignin derivatives including alkali lignin, lignocresol, lignoresorcinol, and lignopyrogallol under the same reaction conditions. The results showed that changing the types of lignin can change the resulting water absorbency. Lignopyrogallol-grafted-polyacrylic acid resin (LP-PAA) showed the highest water absorbency (2137 g/g).

  • Researchpp 6618-6628Bajo Jr, P., and Acda, M. (2017). "Fuel pellets from a mixture of rice husk and wood particles," BioRes. 12(3), 6618-6628.AbstractPDF

    The physical and mechanical properties were studied for fuel pellets made from a mixture of rice husk and Gmelina arborea wood particles. Pellet density, compressive strength, and abrasion resistance were used to evaluate pellet quality at various densification pressures and proportions of rice husk to wood particles. Pellet density and compressive strength increased from 850 to 1070 kg/m3 and 0.61 to 1.2 MPa, respectively, when densification pressure increased from 80 to 120 MPa. The abrasion resistance for all pellet samples in this study was < 2.0%. Proximate analyses of the fuel pellets showed that volatile matter, fixed carbon, and heating value were relatively high and increased with a higher proportion of wood particles. Ash levels were also high (1.3 to 17.8%), which could cause problems with emission and deposition during thermal conversion. In general, except for the ash content, the physical and mechanical properties of pellets made from rice husk and G. arborea wood particles in this study were within the acceptable limits to be used as fuel pellets for industrial heat applications.

  • Researchpp 6629-6655Ahvazi, B., Wojciechowicz, O., Xu, P., Ngo, T. D., and Hawari, J. (2017). "Formation of ligno-polyols: Fact or fiction," BioRes. 12(3), 6629-6655.AbstractPDF

    The physical and chemical characteristics of several lignin-polyol blends were investigated by qualitative and quantitative methods from the view of biobased polyurethane applications. Four differently isolated biomass lignins from forestry and agricultural residues were blended with polyester polyol, and one was blended with polyethylene glycol. The isolated products were examined thoroughly to elucidate the subsequent lignin and polyol interactions during the premixing stage of biobased polyurethane formulation. Polyol was detected in lignin even after vigorous washings with several organic solvents and Soxhlet extraction. The experimental data coupled with two-dimensional heteronuclear multiple quantum coherence (HMQC) and nuclear magnetic resonance (NMR) spectroscopy confirmed the formation of ligno-polyols via strong intermolecular attractions, as well as some linkages between several lignin hydroxyl and polyol functional groups.

  • Researchpp 6656-6664Tee, Y. B., Tee, L. T., Daengprok, W., and Talib, R. A. (2017). "Chemical, physical, and barrier properties of edible film from flaxseed mucilage," BioRes. 12(3), 6656-6664.AbstractPDF

    Chemical, physical, and barrier properties of flaxseed mucilage-based films were investigated to determine the appropriate applications for coating or packaging of food or bioproducts. The film samples were formed via casting with the addition of glycerol as a plasticizer up to a maximum of 5 wt.%. Fourier transform infrared (FTIR) spectra showed an increase of intensity in the –OH stretching vibration region and the appearance of a new peak at 2883.1 cm-1 in the plasticized film samples. These changes may indicate possible interactions between the mucilage and glycerol. With increasing glycerol concentration, the water activity decreased, while the moisture content and water solubility increased. With regard to barrier properties, the water vapour permeability (WVP) and oxygen permeability (OP) notably increased with increasing glycerol content. With these high WVP and OP values, the films can be potentially extended for coating or packaging fresh produce.

  • Researchpp 6665-6678Bazyar, B., and Samariha, A. (2017). "Thermal, flammability, and morphological properties of nano-composite from fir wood flour and polypropylene," BioRes. 12(3), 6665-6678.AbstractPDF

    The thermal, flammability, and morphological properties were investigated for a nano-composite made from fir wood flour and polypropylene. Polypropylene (PP), fir wood flour, maleic anhydride polypropylene (MAPP), and nanosilica at 5 different concentrations (0, 2, 4, 6, and 8 phc), were mixed using an extruder, and samples were made using a hand-press. Then, the hardness and the thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), limited oxygen index (LOI), X-ray diffraction (XRD), and scanning electron microscopy (SEM) results were studied. The results showed that increasing the nanosilica content up to 8 phc increased the hardness. Also, when the nanosilica content was increased to 8 phc, the thermal stability increased and more charcoal was retained. Increasing the nanosilica content increased the crystallization. The limited oxygen index increased. Studying the x-ray diffraction spectrum showed that the width and peak intensity decreased with the increased intake of silica nanoparticles. Scanning electron microscopy images showed that an increased concentration of nanosilica meant better connections and a more uniform bond was established between the fibers and the matrix.

  • Researchpp 6679-6697Hakim Roslan, M. A., Abdullah, N., Abdul Murad, N. Z., Halmi, M. I. E., Idrus, Z., and Mustafa, S. (2017). "Optimisation of extrusion for enhancing the nutritive value of palm kernel cake using response surface methodology," BioRes. 12(3), 6679-6697.AbstractPDF

    The palm kernel cake (PKC) inclusion level in poultry diets is limited by the high indigestible polysaccharides content. Hence, PKC was subjected to an extrusion treatment to reduce the content of these components. The effects of extrusion on the total non-starch polysaccharides (T-NSP), fibre, monosaccharides, and mannooligosaccharides contents were evaluated according to the response surface methodology (RSM) with various temperatures, screw speeds, hopper speeds, and moisture contents. The optimum conditions observed according to the RSM were a temperature of 178 °C, screw speed of 100 rpm, hopper speed of 5 Hz, and moisture content of 75%. The T-NSP content was significantly reduced (p<0.05), from 63.3 ± 1.85% to 57.6 ± 0.89%, and the crude fibre content decreased (p<0.05) from 16.7 ± 0.68% to 13.5 ± 0.99%. The mannose, glucose, and fructose contents of the PKC increased (p<0.05) 2.9-, 1.9-, and 1.4-fold, respectively. The 1,4-β-D-mannobiose, 1,4-β-D-mannotriose, 1,4-β-D-mannotetraose, and 1,4-β-D-mannopentaose increased (p<0.05) 3.7-, 3.8-, 3.5-, and 32.8-fold, respectively. This study showed that extrusion enhanced the nutritive value of PKC.

  • Researchpp 6698-6712Ferrández-García, A., Ferrández-Villena, M., Ferrández-García, C. E., García-Ortuño, T., and Ferrández-García, M. T. (2017). "Potential use of Phoenix canariensis biomass in binderless particleboards at low temperature and pressure," BioRes. 12(3), 6698-6712.AbstractPDF

    Binderless particleboards of Phoenix canariensis were manufactured by hot pressing at a low temperature (120 °C) and low pressure (2.6 MPa). Nine different configurations were analyzed to study different palm tissues. The experimental panels were tested for their mechanical and physical properties according to the procedures defined by the European Union (EN) standards. The microstructure of the raw material was investigated by scanning electron microscopy (SEM) equipped with an energy dispersive X-ray detector for microanalysis (EDXA). The physical and mechanical behavior seemed to be influenced by the amount of parenchymatous tissue. Raw material and particle size have a profound effect on the board properties. The mechanism of self-bonding could have resulted from the high content of sugars, which were partly transformed into furfural. The use of this waste material could be beneficial to the environment because it is a method of carbon fixation, helping to decrease atmospheric CO2.

  • Researchpp 6713-6722Skulcova, A., Majova, V., Kohutova, M., Grosik, M., Sima, J., and Jablonsky, M. (2017). "UV/Vis spectrometry as a quantification tool for lignin solubilized in deep eutectic solvents," BioRes. 12(3), 6713-6722.AbstractPDF

    In this short communication, UV/Vis spectrophotometry is described as an analytical tool for the quantification of lignin content in deep eutectic solutions. The lignin was solubilized with different deep eutectic solvent (DES). DESs were prepared as binary mixtures of choline chloride with lactic acid (1:9); (1:10); ethylene glycol (1:2); glycerol (1:2) and alanine:lactic acid (1:9), and betaine:lactic acid (1:2). The UV-Vis spectrometric quantification of the solubilized lignins was independent of the type of solubilized lignin. The approach consists of measuring the absorbance of a solution of lignins dissolved in the deep eutectic solvents at an absorbance of 440 nm.

  • Researchpp 6723-6735Vivian, M. A., Gomes da Silva Júnior, F., Fardim, P., and Segura, T. E. S. (2017). "Evaluation of yield and lignin extraction from Eucalyptus grandis × Eucalyptus urophylla wood chips with the hydrotropic compound sodium xylenesulphonate (SXS)," BioRes. 12(3), 6723-6735.AbstractPDF

    This study aimed to evaluate the yield and efficiency of lignin extraction from Eucalyptus grandis × Eucalyptus urophylla wood chips from treatments with sodium xylenesulphonate (SXS), and to determine their optimum conditions. First the wood’s physical, chemical, and morphological properties were characterized. Then, the wood chips underwent treatments from a combination of the following factors: time, SXS concentration, and temperature. For each treatment the yield and lignin content remaining in wood chips was determined, from which optimum points were obtained for maximum yield and lignin extraction. The physical, chemical, and morphological characterization showed that the concerned wood showed values in line with those cited in previous literature. Treatments with SXS were efficient in lignin extraction. The treatment that provided the highest calculated yield of wood was 1 h, 0%, 117.5 ºC; and the greatest lignin extraction was with 12 h, 30%, 130 ºC, removing 39.6% of lignin from wood chips. In general, the treatment of E. grandis × E. urophylla wood chips with SXS was effective in extracting lignin. However, the calculated yield and lignin extraction showed antagonistic behaviors; therefore, in light of the objectives, a careful assessment is required when using this treatment on an industrial scale to seek a balance point between the two parameters.

  • Researchpp 6736-6748Xie, G., Zhang, Y., and Lin, W. (2017). "Plasticizer combinations and performance of wood flour–poly(lactic acid) 3D printing filaments," BioRes. 12(3), 6736-6748.AbstractPDF

    Wood flour-poly(lactic acid) 3D printing filaments were prepared via a melt extrusion method. Poplar wood flour and poly(lactic acid) (PLA) were used as raw materials, and different combinations of glycerol and tributyl citrate (TBC) (4% glycerol, 2% glycerol + 2% TBC, 4% TBC) were used as plasticizers. A 3D printer was used to print the filaments into standard test specimens with dimensions of 150 mm × 10 mm × 0.2 mm at the printing temperature of 220 °C. The performance of wood flour-poly(lactic acid) 3D printing filaments in terms of their interfacial compatibility, mechanical properties, melt index (MI), water absorption, and heat stability was tested under different plasticizer combinations. The results showed that under the condition of same dosage of plasticizer, the order of MI for the 3D printed filaments from high to low was 4% glycerol > 2% glycerol + 2% TBC > 4% TBC, which indicated that glycerol was more favorable for the extrusion processing of the composite filaments. However, in terms of compatibility, mechanical properties, water absorption, and thermal stability, the 3D printing filaments with 4% TBC showed better performance compared with other groups.

  • Researchpp 6749-6762Tang, Q., Fang, L., and Guo, W. (2017). "Investigation into mechanical, thermal, flame-retardant properties of wood fiber reinforced ultra-high-density fiberboards," BioRes. 12(3), 6749-6762.AbstractPDF

    The demand has grown in many fields for materials that are eco-friendly and sustainably developed. In this study, several formulations of novel wood fiber reinforced ultra-high-density fiberboards (UHDFs) using resol-type phenolic resin (RTPR) as binders were manufactured for application in decorative building facades. The influences of the various formulations on water resistance and the mechanical, thermal, and fire-resistant properties were systematically examined. All formulations of the UHDFs exhibited better water resistance, internal bonding, and fire resistance as the RTPR content and density increased. To better evaluate mechanical properties, the microstructure of the UHDFs was observed using scanning electron microscopy. After optimization of hot-pressing conditions, UHDFs with excellent mechanical properties of approximately 7.2 GPa, 85.9 MPa, and 5.4 MPa for bending modulus, bending strength, and internal bonding, respectively, were achieved. Good water and flame resistance were also achieved, which makes these materials competitive with other commercial products.

  • Researchpp 6763-6772Ding, Z., Wu, H., and Hu, X. (2017). "Multiple characterization for mechanistic insights of Pb(II) sorption onto biochars derived from herbaceous plant, biosolid, and livestock waste," BioRes. 12(3), 6763-6772.AbstractPDF

    Biochars are considered as promising sorbents for the removal of aqueous metal ions. The aim of this study was to explore the adsorption mechanisms through the integrated characterization of the pristine and Pb(II)-loaded biochars derived from herbaceous plant, biosolid, and livestock waste with different physicochemical properties. The biochar derived from livestock waste exhibited higher Pb sorption capacity than the others. Experimental data of sorption kinetics and isotherms were well fitted by kinetic models and Langmuir isotherm model, respectively. Comparisons of Fourier-transform infrared spectroscopy (FT-IR), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) between the pre- and post-adsorption biochars revealed the formation of Pb-carbonate, suggesting that the surface precipitation was the dominant adsorption mechanism. The combination of multiple characterizations and batch adsorption can make further exploration on the adsorption mechanism of Pb(II) adsorption onto the resultant biochars.

  • Researchpp 6773-6788Razali, N., Hossain, M. S., Taiwo, O. A., Ibrahim, M., Mohd Nadzri, N. W., Razak, N., Mohammad Rawi, N. F., Mohd Mahadar, M., and Mohamad Kassim, M. H. (2017). "Influence of acid hydrolysis reaction time on the isolation of cellulose nanowhiskers from oil palm empty fruit bunch microcrystalline cellulose," BioRes. 12(3), 6773-6788.AbstractPDF

    Cellulose nanowhiskers (CNW) were successfully isolated from oil palm empty fruit bunch microcrystalline cellulose (OPEFB-MCC) through sulfuric acid (H2SO4) hydrolysis with different reaction times. OPEFB-MCC was hydrolyzed with 64 wt.% H2SO4 at 40 °C and various reaction times (30, 60, and 90 min). Effects of the hydrolysis time on the morphologies and properties of the cellulose were evaluated by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). The FTIR analysis showed that the chemical compositions of all of the samples were the same and represented the cellulose I structure. Hydrolysis time had little effect on the crystallinity index of the CNW, as was revealed by the XRD. The TEM images showed that the CNW produced with different reaction times had a rod-like shape and similar diameters and lengths. The produced CNW had better thermal stabilities than the OPEFB-MCC.

  • Researchpp 6789-6811Rao, F., Chen, Y., Li, N., Zhao, X., Bao, Y., Wu, Z., Ren, D., Xu, J., and Cai, H. (2017). "Preparation and characterization of outdoor bamboo-fiber-reinforced composites with different densities," BioRes. 12(3), 6789-6811.AbstractPDF

    Outdoor bamboo-fiber-reinforced composites (OBFRCs) with four different densities were prepared, and the microstructure and physicomechanical properties of pristine samples were evaluated. In addition, the surface color, glossiness, roughness, water absorption, and wettability of the samples were tested to investigate the effects of panel density on the extent of surface weathering due to ultraviolet radiation. The results showed that the OBFRCs exhibited excellent physical and mechanical properties, which improved with increasing density. However, increases in the density led to decreases in the hygroscopicity and dimensional stability of the OBFRCs. After weathering, the surface contact angle and surface roughness increased, and the dimensional stability improved. The surface glossiness, water absorption, and surface free energy decreased. A higher density resulted in improved color stability, which suggested that density played an important role in determining surface photodegradation properties. Thus, density-increasing treatments had positive effects on the physical and mechanical properties as well as the color stability and wettability of the OBFRCs, but they may negatively affect the roughness and dimensional stability. Based on service-performance and cost-minimization considerations, 1.1 g/cm3 was determined as the most appropriate density for general applications.

  • Researchpp 6812-6831Liu, M., Yang, S., Long, L., Wu, S., and Ding, S. (2017). "The enzymatic deinking of waste papers by engineered bifunctional chimeric neutral lipase – endoglucanase," BioRes. 12(3), 6812-6831.AbstractPDF

    Endoglucanase and lipase showed good deinking efficiency for waste papers. The performances could be greatly improved further by the combined use of the two enzymes. To reduce the enzyme production cost and enhance synergistic action of endoglucanase and lipase on laser-printed paper and newspaper, a chimeric enzyme with endoglucanase and lipase activity was constructed and expressed in Pichia pastoris. The data indicated that the chimera Lip-EG1CD improved the ink removal efficiencies and sheet brightness better than a single enzyme or a mixture of two enzymes. The chimera Lip-EG1CD demonstrated an 89% removal of toner on both papers and 91% ISO and 60% ISO sheet brightness for laser-printed paper and newspaper, respectively. Handsheet strength was also clearly improved. It revealed that the combined deinking of endoglucanase and lipase on waste papers could be strengthened by constructing proper chimera due to intramolecular synergistic action. This would be useful for developing an economical process for waste paper recycling.

  • Researchpp 6832-6843Zhang, Q., Xu, M., Xing, L., Dang, C., Han, X., and Pu, J. (2017). "Enzymatic assisted ultrasonic pretreatment’s effect on poplar pulp properties," BioRes. 12(3), 6832-6843.AbstractPDF

    A combined process consisting of an enzymatic pretreatment of small poplar wood chips, followed by an ultrasonic treatment was proposed and performed. Under the ultrasonic action of cavitation, thermal, and mechanical effects, the two processes of pulping and bleaching can be completed in one procedure. Before the ultrasonic treatment assisted pulping, an enzyme pretreatment was used to destroy the bonds between the cellulose, hemicellulose, and lignin to make the subsequent ultrasonic treatment exhibit higher selectivity and efficiency. This provided a poplar ultrasonic assisted pulp (PUP) with a 75% yield. A further analysis of the pulp, utilizing a scanning electron microscope (SEM), showed the fine fibrillation degree of the fiber surface of PUP was comparable to the traditional poplar chemimechanical pulp (PMP) and poplar chemical pulp (PCP). Thermogravimetric analysis and Raman analysis showed that the final residue obtained from the PUP was 20%. In addition, a decorative base paper was successfully made using the poplar ultrasonic pulp, and the physical properties reached or exceeded the industry standard of decorative base paper.

  • Reviewpp 6844-6867Chin, K., Ibrahim, S., Hakeem, K., H’ng, P., Lee, S., and Mohd Lila, M. (2017). “Bioenergy production from bamboo: Potential source from Malaysia’s perspective,” BioRes. 12(3), 6844-6867.AbstractPDF
    Global energy sectors are facing the crucial challenge of sustainability and diversification of energy resources. Seeking renewable resources with a sustainable supply is therefore a matter of the utmost concern. In this respect, bamboo, a renewable lignocellulosic material and non-food biomass, has great potential to be utilized to produce energy. Several studies have been conducted on a wide range of bamboo species and the results have shown that bamboo could potentially be used as a suitable fuel because it shares desirable fuel characteristics present in other woody biomass. Bamboo can be used as an energy source by converting it into solid, liquid, and gaseous fuels. However, to utilize bamboo as a high promise energy crop resource for biofuels, a secure and stable supply is required. Therefore, additional information on the availability, cultivation, and harvesting operations of bamboo is vital to ensure the practicability of the idea. The objective of this review is to highlight the potential of bamboo as an alternative source of bioenergy production, particularly in a Malaysian context, with emphasis on the concepts, pretreatment, and conversion technologies.
  • Reviewpp 6868-6884Radics, R. I., Gonzalez, R., Bilek, E. M., and Kelley, S. S. (2017). "Systematic review of torrefied wood economics," BioRes. 12(3), 6868-6884.AbstractPDF

    This literature review aims to provide a systematic analysis of studies on the financial aspects of producing torrefied biomass and torrefied pellets. There are substantial differences in the specific technologies, operating conditions, scale of the demonstration, and properties of biomass feedstock. There is a lack of reports that consider the entire supply chain, which is required for an understanding of the high-cost steps. To obtain a robust view of the torrefaction processes’ financial prospects the authors have used both peer-reviewed and non-peer-reviewed papers that allowed the researchers to include thirty-one papers in this analysis. All these studies establish that the prices of the biomass and the final torrefied product are critical. The product yield and caloric content, which are related to pricing, were also key financial drivers. The lower freight costs due to high-energy density of the torrefied pellets was recognized and calculated, but some other benefits were not quantified. There is a need for a detailed and flexible torrefaction financial model that includes variations in financial assumptions and biomass properties. Given the uncertainty around many specific steps, there is value in including stochastic tools in these financial analyses.

  • Reviewpp 6885-6901Komesu, A., Wolf Maciel, M. R., and Maciel Filho, R. (2017). "Separation and purification technologies for lactic acid – A brief review," BioRes. 12(3), 6885-6901.AbstractPDF

    Lactic acid is an important platform chemical with a wide range of applications. Production of lactic acid by fermentation is advantageous because renewable and low cost raw materials can be used as substrates. After fermentation, the broth needs to be purified to obtain pure lactic acid for further uses. Thus, efficient downstream processes are very important because they account for 50% of the production costs. This review discusses different processes that are currently employed for lactic acid recovery, focusing on precipitation, solvent extraction, and separation with membranes. Advances in such recovery processes and drawbacks that limit the application of these technologies at the industrial level are also presented.