NC State
  • Editorialpp 452-455Sun, R.-C. (2009). "Detoxification and separation of lignocellulosic biomass prior to fermentation for bioethanol production by removal of lignin and hemicelluloses" BioRes. 4(2), 452-455.AbstractPDF

    Lignocellulosic materials such as agricultural residues have been recognized as potential sustainable sources of mixed sugars for fermentation to bioethanol. To obtain a high overall ethanol yield and achieve an economically feasible production process, the removal of lignin and hemicelluloses improves the accessibility of cellulosic material to hydrolytic enzymes and avoids the degradation products that are inhibitory to the yeast used in the subsequent fermentation. Technological advances, e.g., environmentally friendly removal of lignin and hemicelluloses from lignocellulosic biomass prior to fermentation of the librated glucose from cellulose into bioethanol, has the potential to provide for sustainable and cost effective production of biofuel.

  • Editorialpp 456-457Cheng, S., and Zhu, S. (2009). "Lignocellulosic feedstock biorefinery - The future of the chemical and energy industry," BioRes. 4(2), 456-457.AbstractPDF
    The sustainable development of the chemical and energy industry is an indispensable component of our sustainable society. However, the traditional chemical and energy industry depends heavily on such non-renewable fossil resources as oil, coal, and natural gas. Its feedstock shortage and the resultant environmental and climatic problems pose a great threat for any type of sustainable development. Lignocellulosic materials are the most abundant renewable resources in the world, and their efficient utilization provides a practical route to address these challenges. The lignocellulosic feedstock bio-refinery is an effective model for the comprehensive utilization of lignocellulosic materials, and it will play vital role in the future development of chemical and energy industry.
  • Researchpp 458-470Xiu, S., Zhang, Y., and Shahbazi, A. (2009). "Swine manure solids separation and thermochemical conversion to heavy oil," BioRes. 4(2), 458-470.AbstractPDF
    Separation of solids from liquid swine manure and subsequent thermochemical conversion (TCC) of the solids fraction into oil is one way of reducing the waste strength and odor emission. Such processing also provides a potential means of producing renewable energy from animal wastes. Gravity settling and mechanical separation techniques, by means of a centrifuge and belt press, were used to remove the solids from liquid swine manure. The solid fractions from the above separation processes were used as the feedstock for the TCC process for oil production. Experiments were conducted in a batch reactor with a steady temperature 305 oC, and the corresponding pressure was 10.34 Mpa. Gravity settling was demonstrated to be capable of increasing the total solids content of manure from 1% to 9%. Both of the mechanical separation systems were able to produce solids with dry matter around 18% for manure, with 1% to 2% initial total solids. A significant amount of volatile solid (75.7%) was also obtained from the liquid fraction using the belt press process. The oil yields of shallow pit manure solids and deep pit manure solids with belt press separation were 28.72% and 29.8% of the total volatile solids, respectively. There was no visible oil product obtained from the deep pit manure solids with centrifuge separation. It is believed that it is the volatile solid content and the other components in the manure chemical composition which mainly determine the oil production.
  • Researchpp 471-481Jahan, M. S., Sabina, R., Tasmin, B., Chowdhury, D. A. N., Noori, A., and Al-Maruf, A. (2009). "Effect of harvesting age on the chemical and morphological properties of dhaincha (Sesbania aculeata) and its pulpability and bleachability," BioRes. 4(2), 471-481.AbstractPDF
    Dhaincha (Sesbania aculeata) is one of the annual plants in Bangladesh that has potential as a fiber source. It is a crop generally cultivated for its nutritive value to soil. This paper describes the effect of harvesting age of dhaincha on chemical, morphological, pulp, and papermaking properties and its bleachability. Dhaincha is a short length fiber that can be used as a substitute to hardwood. Fiber length was found to increase slightly with increasing age of the plant. The alpha-cellulose content in dhaincha increased and pentosan decreased with increasing age. Dhaincha pulp was prepared from 2, 3, 4, 5, and 6 month old plants under identical cooking conditions. Pulp yield (43-45 %) and kappa number (26-30) did not follow direct correlation with plant age. But physical properties of unbleached pulp increased linearly with the increase of age. Bleachability of dhaincha pulp was quite poor. The bleachability of pulp was improved when the age of dhaincha was increased.
  • Researchpp 482-496Mattinen, M.-L., Stuijs, K., Suortti, T., Mattila, I., Kruus, K., Willför, S., Tamminen, T., and Vincken, J.-P. (2009). "Modification of lignans by Trametes hirsuta laccase," BioRes. 4(2), 482-496.AbstractPDF
    Oxidative polymerization of two isolated lignans, secoisolariciresinol, and secoisolariciresinol diglucoside, as well as the lignan macromolecule, by a high redox potential Trametes hirsuta laccase was studied with different analytical methods. The reactivity of laccase with the different compounds was studied by an oxygen consumption measurement. The polymerization of laccase-treated lignans was evidenced by size exclusion chromatography, reversed phase - high performance liquid chromatography, and matrix-assisted laser desorption/ionisation - time of flight mass spectrometry. The data showed that the selected substrates could be oxidised by laccase. Secoisolariciresinol and secoisolariciresinol diglucoside were polymerized by laccase to a similar extent. The lignan macromolecule reacted to a lesser extent. Polymerization of the macromolecule proceeded mainly via its secoisolariciresinol diglucoside moieties. Furthermore, it was shown that ferulic acid can be linked to polymerized secoisolariciresinol via decarboxylation by laccase. This investigation showed that lignans can be enzymatically modified by Trametes hirsuta laccase.
  • Researchpp 497-508Yokota, S., Ohta, T., Kitaoka, T., Ona, T., and Wariishi, H. (2009). "Preparation and characteristics of anionic polyacrylamides containing direct dye with a high affinity for cellulose," BioRes. 4(2), 497-508.AbstractPDF
    Direct dye with a high affinity for cellulose substrate was utilized as a cellulose anchor to promote retention of paper strengthening additives under various conditions associated with the wet end of a paper machine. Direct Red 28 (DR) was covalently linked to anionic polyacrylamide (A-PAM) via a condensation reaction using water-soluble carbodiimide. The DR-conjugated A-PAM (DR-A-PAM) demonstrated good retention efficiency, resulting in strength enhancement of handsheets. Anionic trash showed no interference with the performance of DR-A-PAM in the wet end, while the additive performance was sensitive to calcium ions. Surface plasmon resonance analysis gave useful information on the cellulose-anchoring ability of DR-A-PAM. Dye molecules were irreversibly adsorbed onto the cellulose substrate under aqueous conditions, while A-PAM possessed no significant affinity for cellulose. These results suggest that anionic DR moieties in DR-A-PAM molecules served as a cellulose-anchor, possibly due to multiple CH-π interaction between hydrophobic face of cellulose substrate and π-conjugated system of dye molecules. Such a unique interaction of direct dye and cellulose provides a new insight into the wet end system, and does not depend on conventional electrostatic attraction.
  • Researchpp 509-521Vynios, D. H., Papaioannou, D. A., Filos, G., Karigiannis, G., Tziala, T., and Lagios, G. (2009). "Enzymatic production of glucose from waste paper," BioRes. 4(2), 509-521.AbstractPDF
    Municipal wastes have become a severe problem in developed and developing countries during the last century, paper being the main constituent. Not all of the waste paper can be recycled, and therefore alternative procedures for the use of the remaining material should be pursued. The aim of the present work was the application of cellulases for waste paper treatment and the subsequent glucose production and optimization of the conditions for such treatment. Glucose thereafter can be utilized for production of ethanol or other chemicals by specific microbial cultures. The work focused in the stabilization of cellulases by cross-linking or by the addition of specific crown ether based compounds to improve glucose production. The results indicated that enzymatic treatment of waste paper is of particular interest, since it may be an alternative way to carry out municipal wastes treatment and concomitant glucose production. By the application of the proposed procedure, the total amounts of municipal wastes can be greatly reduced and production of bioethanol can be achieved.
  • Researchpp 522-528Dwivedi, U. K., Ghosh, A., and Chand, N. (2009). "Role of PVA modification in improving the sliding wear behavior of bamboo," BioRes. 4(2), 522-528.AbstractPDF
    This experimental study was conducted to investigate the role of poly-vinyl-alcohol (PVA) treatment in improving the sliding wear behaviour of pure bamboo. The effects of dipping time in PVA solution and applied load on wear behaviour of bamboo samples were determined. The wear volume of bamboo was reduced when it was treated with PVA. The wear volume during sliding was increased with increasing of applied load, whereas the coefficient of friction was reduced on PVA treatment. Worn surfaces were observed by using SEM and discussed to explain the mechanism of wear.
  • Researchpp 529-536Lundquist, K., Langer, V., and Parkås, J. (2009). "The structure and conformation of lignin as judged by X-ray crystallographic investigations of lignin model compounds: Arylglycerol beta-syringyl ethers," BioRes. 4(2), 529-536.AbstractPDF
    Structural elements of the arylglycerol b-syringyl ether type are very frequent in hardwood lignins. A variety of crystalline dimeric lignin models representing different diastereomeric forms of structural elements in lignin of this type have been studied using X-ray crystallography. Bond distances and bond angles in the model compounds are in all probability nearly identical with those of the corresponding structural elements in lignins. Special attention was paid to the geometry of the b-O-syringyl linkage, since the reactivity of this linkage is of particular interest in connection with pulping reactions. The crystal structures of the model compounds suggest that two types of conformations are predominating; in both of them the aromatic rings are separated by ca. 4.5 Å (maximal distance 4.9-5 Å). Based on X-ray crystallographic data from four compounds a sequence of units (5 aromatic rings, 8 chiral C-atoms) attached to each other by b-syringyl ether linkages was constructed. The appearance of the resulting oligomer illustrates that stereoisomerism can be expected to influence the shape of the lignin molecules to a great extent.
  • Researchpp 537-543Chi, C., Zhang, Z., Ge, W., and Jameel, H. (2009). "The relationship between two methods for evaluating five-carbon sugars in eucalyptus extraction liquor," BioRes. 4(2), 537-543.AbstractPDF
    Alkaline pre-extraction and hydrothermal hydrolysis were carried out with eucalyptus chips. Two methods were used to determine and calculate the extraction yield of five-carbon sugars. One is an indirect method, based on the difference of pentosan content between the chips before and after pre-extraction. The other method is to directly measure the content of five-carbon sugars in the extracting solution. The results indicated that there was a defined relationship between the two methods. For alkaline pre-extraction, a good logarithmic relationship was shown. There was a good linear relationship for hot water prehydrolysis. So the pentosan content of the extracted chips could be predicted from the results of the latter method, referring to the two relational expressions. In this study, a simple and rapid method of spectrophotometry was introduced, which will help in the evaluation of extraction yield of five-carbon sugars during biomass processing.
  • Researchpp 544-553Singh, G., Ahuja, N., Sharma, P., and Capalash, N. (2009). "Response surface methodology for the optimized production of an alkalophilic lassase from gamma-proteobacterium JB," BioRes. 4(2), 544-553.AbstractPDF
    Gamma-proteobacterium JB, an alkali-tolerant soil isolate, produced laccase (8X103 nkat/L) in M162 medium. The optimization of process conditions (pH, incubation time, agitation, and CuSO4 concentration) for laccase production during submerged fermentation was carried out using response surface methodology (RSM) based on a central composite design (CCD). Maximum laccase production achieved was 7.4 X 104 nkat/L at pH 8.0, 210 rpm, 100 µM of CuSO4 after 60 h of incubation. This design of experiment methodology increased laccase production by 9.3 fold over the control. Experimental findings were in close agreement with the model predictions.
  • Researchpp 554-565Treimanis, A., Grinfelds, U., and Skute, M. (2009). "Are the pulp fiber wall surface layers the most resistant ones towards bleaching?" BioRes. 4(2), 554-565.AbstractPDF
    The residues of the wood cell wall compound middle lamella affect the composition of the relevant pulp fiber surface layers and influence the fibers’ bleachability. The objective of the present work was to separate the eucalyptus kraft and birch organosolv pulp fiber wall surface layers by hydromechanical peeling and to proceed with enzyme boosted bleaching of the separated fiber wall layers. The initial content of lignin and heteroaromatic compounds (“false” lignin) was determined by chemical methods and UV-spectra. The separated fiber wall surface layers representing the residues of the primary wall P and outer layer S1 of the secondary wall, as well as the main part of the secondary wall were exposed to the bleaching sequence peroxide-xylanase treatment-alkaline extraction-peroxide (P1-X-E-P2). brightness measurements revealed significant distinctions between the preparations. The final brightness of the main part of eucalyptus kraft pulp fibers reached 67%, while the brightness of the surface layers attained only 50% ISO. Similar results were obtained for birch organosolv pulp. It was concluded that the main reason for the described phenomena is the discordant chemical composition of the different fiber wall layers.
  • Researchpp 566-588Mwaikambo, L. Y. (2009). "Tensile properties of alkalised jute fibres," BioRes. 4(2), 566-588.AbstractPDF
    The structure of jute fibre has been modified using caustic soda up to a limit in order to improve its performance. The SEM micrographs of untreated jute fibres show a smooth surface, while alkalised jute fibres show rough and void regions between individual fibre cells. The study showed that the tensile strength and Young’s modulus of jute fibre bundles depends on the physical characteristics of its internal structure such as the cellulose content, changes in the crystalline region content expressed in terms of crystallinity index, and micro-fibril angle. Results also showed tensile properties optimised at 0.24% NaOH (w/w). Overall, alkalised fibres exhibit brittle fracture. The study demonstrated the dependence of tensile properties on the changes in fibre structure following alkalisation.
  • Researchpp 589-601Li, Z., Pang, Y., Lou, H., and Qiu, X. (2009). "Influence of lignosulfonates on the properties of dimethomorph water-dispersible granules," BioRes. 4(2), 589-601.AbstractPDF
    Different molecular weight fractions of lignosulfonates (LS), LS having different cations, and modified LS with different degree of sulfonation and intrinsic viscosity were prepared and used as dispersants for Dimethomorph water-dispersible granules (DWG). The suspending ratio of DWG was tested to evaluate the effectiveness of LS as a dispersant. Moreover, the stability of DWG suspensions was measured by a new instrument (Turbiscan LabExpert). The suspending ratios of DWG having different molecular weight fraction of LS increased with increasing molecular weight in a suitable range. The kind of cation associated with the LS didn’t have an obvious influence the effectiveness of LS as a dispersant. Furthermore, the higher degree of sulfonation of LS, of which the intrinsic viscosity was similar, the better was its effectiveness as a dispersant. When the intrinsic viscosity increased within a suitable range, the effectiveness of LS as a dispersant increased. Similar findings were achieved by evaluating the stability of DWG suspensions with all the LS as dispersants, and larger molecular weight could decrease the growth of particle size.
  • Researchpp 602-625Salmi, J., Nypelö, T., Österberg, M., and Laine, J. (2009). "Layer structures formed by silica nanoparticles and cellulose nanofibrils with cationic polyacrylamide (C-PAM) on cellulose surface and their influence on interactions," BioRes. 4(2), 602-625.AbstractPDF
    A quartz crystal microbalance with dissipation monitoring (QCM-D) was used to study the adsorption of the layer formed by silica nanoparticles (SNP) and cellulose nanofibrils (NFC) together with cationic polyacrylamide (C-PAM) on cellulose surface, accompanied by use of atomic force microscope (AFM) to study the interactions between cellulose surfaces. The purpose was to understand the multilayer build-up compared to complex structure adsorption. The layer thickness and consequently also the repulsion between surfaces increased with each addition step during layer formation in the SNP-C-PAM systems, whereas the second addition of C-PAM decreased the repulsion in the case of NFC-C-PAM multilayer formation. An exceptionally high repulsion between surfaces was observed when nanofibrillar cellulose was added. This together with the extremely high dissipation values recorded with QCM-D indicated that nanofibrillar cellulose formed a loose and thick layer containing a lot of water. The multilayer systems formed fully and uniformly covered the surfaces. Silica nanoparticles were able to penetrate inside the loose C-PAM structure due to their small size. In contrast, NFC formed individual layers between C-PAM layers. The complex of C-PAM and SNP formed only a partly covered surface, leading to long-ranged pull-off force. This might explain the good flocculation properties reported for polyelectrolyte-nanoparticle systems.
  • Researchpp 626-639Jonoobi, M., Harun, J., Shakeri, A., Misra, M., and Oksman, K. (2009). "Chemical composition, crystallinity, and thermal degradation of bleached and unbleached kenaf bast (Hibiscus cannabinus) pulp and nanofibers," BioRes. 4(2), 626-639.AbstractPDF
    Kenaf (Hibiscus cannabinus) nanofibers were isolated from unbleached and bleached pulp by a combination of chemical and mechanical treatments. The chemical methods were based on NaOH-AQ (anthraquinone) and three-stage bleaching (DEpD) processes, whereas the mechanical techniques involved refining, cryo-crushing, and high-pressure homogenization. The size and morphology of the obtained fibers were characterized by environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM), and the studies showed that the isolated nanofibers from unbleached and bleached pulp had diameters between 10-90 nm, while their length was in the micrometer range. Fourier transform infrared (FTIR) spectroscopy demonstrated that the content of lignin and hemicellulose decreased in the pulping process and that lignin was almost completely removed during bleaching. Moreover, thermogravimetric analysis (TGA) indicated that both pulp types as well as the nanofibers displayed a superior thermal stability as compared to the raw kenaf. Finally, X-ray analyses showed that the chemo-mechanical treatments altered the crystallinity of the pulp and the nanofibers: the bleached pulp had a higher crystallinity than its unbleached counterpart, and the bleached nanofibers presented the highest crystallinity of all the investigated materials.
  • Researchpp 640-658Liimatainen, H., Haapala, A., Tomperi, J., and Niinimäki, J. (2009). "Fibre floc morphology and dewaterability of a pulp suspension: Role of flocculations kinetics and characteristics of flocculation agents," BioRes. 4(2), 640-658.AbstractPDF
    The aim of this investigation was to find out how properties of a flocculation agent and flocculation kinetics affect the morphology of fibre flocs and how dewatering of a fibre suspension may be attributed to floc morphology. Fibre flocculation, analysed in terms of floc size, mass fractal dimension, floc strength, and the kinetic constant of flocculation, was measured with a digital image analysis system using cationic polyacrylamides as flocculants and NaCl as a coagulant. The results suggest that the kinetics of fibre flocculation is not a key factor determining floc properties but follows from the high bonding ability of the flocculation agent, which also lies behind the high floc density and size, i.e., the factors that lead to fast flocculation and improved floc properties are partly the same. In addition to interfibre bonding strength, the structure of the bonding layer of polymeric flocculants was found to be a significant factor describing floc morphology. Dewaterability of the fibre suspension was improved by increased floc density, which promotes fast water flow through the large voids around the dense flocs, while large, irregular flocs induced loose floc packing, which further improved dewatering by creating larger voids. Increased floc strength seemed to reduce the sealing of fluid passageways, particularly on the surface of the wire, where fibre squeezing could blind the filter fabric.
  • Researchpp 659-673Ghosh, S. C., Militz, H., and Mai, C. (2009). "Natural weathering of Scots pine (Pinus sylvestris L.) boards modified with functionalised commercial silicone emulsions," BioRes. 4(2), 659-673.AbstractPDF
    A quat-silicone micro-emulsion (particle size <40 nm), an amino-silicone macro-emulsion (110 nm), and an alkyl modified silicone macro-emulsion (740 nm) were used to modify Scots pine (Pinus sylvestris L.) sapwood. Treated and uncoated boards were exposed to natural weathering for one year along with water treated controls according to EN 927-3. The treatment with silicone emulsions did not enhance the color stability, which was assessed at three months intervals using a spectrophotometer and classified according to the CIE-Lab system. Treatment with amino-silicone emulsions gave a more yellowish appearance of the wood surface before weathering than the other silicones and the control. Boards treated with quat- and amino-silicone were less overgrown by staining fungi and displayed reduced surface roughness than those treated with alkyl-modified silicone and the control samples.
  • Researchpp 674-686Zhuang, J., Liu, Y., Wu, Z., Sun, Y., and Lin, L. (2009). "Hydrolysis of wheat straw hemicellulose and detoxification of the hydrolysate for xylitol production," BioRes. 4(2), 674-686.AbstractPDF
    Xylitol can be obtained from wheat straw hemicellulose containing a high content of xylan. This study describes a new system of hydrolysis, utilizing a mixed solution of formic acid and hydrochloric acid in which xylan can be hydrolyzed effectively. The hydrolysate contains a high content of formic acid, which markedly inhibits the fermentation. One of the most efficient methods for removing inhibiting compounds is treatment of the hydrolysate with ion-exchange resins. Formate can be removed by a factor of 77.78%, and furfural, acetic acid, phenolic compounds can be removed by 90.36%, 96.29%, and 77.44%, respectively after the hydrolysate has been treated with excess Ca(OH)2 and D311 ion-exchange resin. The xylose from the hydrolysis process can be fermented by Candida tropicalis strain (AS2.1776) to produce xylitol with a yield of 41.88 % (xylitol/xylose).
  • Researchpp 687-703Leschinsky, M., Sixta, H., and Patt, R. (2009). "Detailed mass balances of the autohydrolysis of Eucalyptus globulus at 170 oC," BioRes. 4(2), 687-703.AbstractPDF
    Autohydrolysis of Eucalyptus globulus was conducted at three different intensity levels typical for prehydrolysis kraft pulping as utilized for manufacturing dissolving pulp grades. The objective was to establish for the autohydrolysis process a detailed mass balance comprising the chemical composition of all three phases: the autohydrolysate, the released gas, and the solid residue. Carbohydrate determination involved both acid methanolysis combined with gas chromatography (GC) and sulfuric acid total hydrolysis with high performance anion exchange chromatography (HPAEC) coupled with pulsed amperometric detection (PAD); this allowed reliable quantification of neutral as well as acidic sugar units in cellulosic and non-cellulosic polysaccharides. Uronic acids present in the Eucalyptus globulus wood were progressively degraded through decarboxylation, leading to substantial carbon dioxide formation. The degree of acetylation of xylan remaining in the wood residue was clearly reduced, while the amount of bound acetyl groups in dissolved xylo-oligosaccharides (XOS) stayed relatively constant as a function of autohydrolysis intensity. The bulk of the lignin that was dissolved during autohydrolysis could be attributed to the acid-soluble lignin content of the wood. Only small amounts of Klason lignin were dissolved.
  • Researchpp 704-713Jin, F., and Enomoto, H. (2009). "Hydrothermal conversion of biomass into value-added products: Technology that mimics nature," BioRes. 4(2), 704-713.AbstractPDF
    The term “hydrothermal” comes originally from the field of geology. Hydrothermal reactions generally can be defined as reactions in the presence of aqueous solvents under high temperature and pressure. Such reactions played a very important role during formation of fossil fuels. On the basis of the natural phenomena, we have conducted a series of studies concerning hydrothermal conversion of biomass into value-added products. This article gives an overview of some recent advances in our research on hydrothermal conversion of biomasses, mainly including the production of low molecular weight carboxylic acids, such as acetic acid, lactic acid, and formic acid, from carbohydrate and lignocellulosic biomasses, as well as glycerin, which is a by-product of the bio-diesel fuel manufacturing process.
  • Researchpp 714-729Ford, E., Popil, R. E., and Kumar, S. (2009). "Breathable water-resistant linerboard coatings by electrospraying application," BioRes. 4(2), 714-729.AbstractPDF
    Waterproofing of corrugated packaging with wax or polyethylene hinders recyclability and so is incompatible with current socioeconomic goals of sustainability. Therefore, alternative coating technologies are sought. This study describes our feasibility study of electrohydrodynamic spraying (EHS) towards waterproofing corrugated boxes. Water resistance properties of electro-sprayed polymer-solvent solutions and latex systems air dried onto linerboard surface are reported. Optimization of spraying parameters led to observations of applied coating roughening on a nano-to-micron scale that correlated with increased water contact angle of the treated linerboard. An EHS latex formulation, compared to polymer solvent system, has shown better adhesion to linerboard. EHS application of latex produced a surface coating texture of droplets, which minimizes liquid water absorption, forming a nanopore matrix (of 3 – 50 nm diameter pores) that enabled the transmission of water vapor. Linerboard treated by EHS latex was advantageously found to be comparatively transpiring to water vapor at room temperature and refrigeration conditions, which is encouraging for commercial application of the technique.
  • Researchpp 730-739Ray, D., Das, M., and Mitra, D. (2009). "Influence of alkali treatment on creep properties and crystallinity of jute fibres," BioRes. 4(2), 730-739.AbstractPDF
    In this work, the effect of the alkali-treatment and its variables viz., time and concentration of alkali, on the creep properties of jute fibre were studied. It was demonstrated that this kind of treatment leads to several changes in fine structure, such as voids creation and fibre fibrillation. The creep behaviour was measured for the alkali treated as well as the dewaxed fibres. Creep value was much higher in the 17.5% NaOH treated fibres compared to the dewaxed fibres. In the 8 hrs treated fibres, the creep was slightly more than the 20 mins treated fibres. XRD study revealed that experimental alkali treatment conditions resulted in closer packing of cellulose chains or rather increased crystallinity. Hence closer arrangement of the molecular chains (higher crystallinity) will reduce the creep extension, as expected.
  • Researchpp 740-755Tazrouti, N., and Amrani, M. (2009). "Chromium (VI) adsorption onto activated kraft lignin produced from alfa grass (Stipa tenacissima)," BioRes. 4(2), 740-755.AbstractPDF
    Activated lignin having a surface area of 1023 m2 g-1 has been prepared from sulfate lignin that was treated by 30% H2O2 and carbonized at 300 °C in order to test the chromium (VI) adsorption from aqueous solution. The influence of contact time, pH, initial concentrations of adsorbent and adsorbate, and temperature on the adsorption capacity were investigated. The maximum removal of Cr(VI) was found to be 92.36 % at pH=2 and a contact time of 80 min. Optimal concentration of lignin and Cr(VI) were found to be 3.8 g L-1 and 180 mg L-1, respectively. The adsorption kinetics data fitted well with a pseudo-second-order equation, and the rate of removal of chromium was found to speed up with increasing temperature. Activation energy for the adsorption process was found to be 18.19 kJ mol-1. The Langmuir and Freundlich adsorption isotherm models were applied to describe the isotherm and isotherm constants for the adsorption of Cr (VI) on lignin. These constants and correlation coefficients of the isotherm models were calculated and compared. Results indicated that Cr (VI) uptake could be described by the Langmuir adsorption model. The maximum adsorption capacity (qm) of Cr (VI) on lignin was 75.75 mg g-1 at 40°C. The dimensionless equilibrium parameter (RL) signified a favorable adsorption of Cr (VI) on lignin and was found to be between 0.0601 and 0.818 (0<RL<1). The thermodynamic parameters such as ΔG°, ΔS°, and ΔH° were calculated, and it was found that the reaction was spontaneous and endothermic in nature. This study indicates that lignin has the potential to become an effective and economical adsorbent for removal Cr (VI) from waste water.
  • Researchpp 756-770Uysal, B., Kurt, Ş, and Özcan, C. (2009). "Thermal conductivity of laminated veneer lumbers bonded with various adhesives and impregnated with various chemicals," BioRes. 4(2), 756-770.AbstractPDF
    Desmodur VTKA and Urea formaldehyde) on wooden materials (Scotch pine and oriental beech) cut tangentially and radially impregnated with Tanalith-C, creosote, and sodium silicate in layer (3, 4, 5) of laminated veneer lumber (LVLs) on thermal conductivity. The lowest thermal conductivity of 0.103 Kcal/mh°C was obtained in Scotch pine, cut tangentially, impregnated with creosote, bonded with urea formaldehyde, and 3 layer LVL. The highest thermal conductivity of 0.185 Kcal/mh°C was obtained in oriental beech, cut radially, impregnated with Tanalith-C, bonded with PVAc, and 5 layers LVL. Consequently, oriental beech wood cut radially and impregnated with Tanalith-C, bonded with PVAc adhesive and 5 layers in LVL can be used as a material in construction where the thermal conductivity is required. Scotch pine wood cut tangentially and impregnated with creosote, bonded with urea formaldehyde adhesive and 3 layers in LVL can be used as a material in construction where the insulation is required.
  • Researchpp 771-788Pedieu, R., Riedl, B., and Pichette, A. (2009). "Properties of birch outer bark panels reinforced with wood strands in the surface layers," BioRes. 4(2), 771-788.AbstractPDF
    The high demand of wood as a raw material can be expected to soon lead to a severe shortage, resulting in drastic competition between various mills. This competition will be worsened by a restriction of forest cuttings in Quebec. One of the solutions to this problem would be to develop a mixed panel in which the strands of core layer are substituted by outer bark particles, and in this particular case, by particles of white birch. This type of panel could be used as siding panels and for the fabrication of boxes, bins, and commercial shelving. The objective of the present research work concerns the design, the manufacture, and the evaluation of mechanical and physical properties of this type of panel. Two manufacturing factors were taken into account: the strands orientation in the face layers and the alkali treatment made on the bark particles used in the core layer. All produced mixed panels met and exceeded almost all CAN3-0437 R-1 and O-1 property requirements. The alkali treatment of bark particles did not improve the mechanical properties of manufactured panels. The statistical analysis method that was used made it possible to choose the panel with non-oriented wood strands in the surface layers and alkali treated bark particles in the core layer as the best by taking into account only the bending strengths in both major and side axes of a panel.
  • Researchpp 789-804Sukhbaatar, B., Steele, P. H., and Kim, M. G. (2009). "Use of lignin separated from bio-oil in oriented strand board binder phenol-formaldehyde resins,"BioRes. 4(2), 789-804.AbstractPDF
    Bio-oil produced from fast pyrolysis of biomass has been investigated as a renewable fuel and as a source of industrial chemicals. The lignin fraction of bio-oil produced from wood in our fast pyrolysis reactor was separated by using only water and methanol with a 25% yield based on bio-oil weight. This separation procedure appears to be of lower cost than the reported extraction procedure using ethyl acetate as solvent. The isolated pyrolytic lignin was smoothly incorporated into phenol-formaldehyde resins at 30%, 40%, and 50% phenol replacement levels, and the resultant resins were evaluated as oriented strand board core-layer binders. The evaluation results indicated that the pyrolytic lignin is effective for up to about 40% replacement of phenol in synthesizing wood adhesive type PF resins.
  • Researchpp 805-815Košíková, B., and Lábaj, J. (2009). "Lignin-stimulated protection of polypropylene films and DNA in cells of mice against oxidation damage," BioRes. 4(2), 805-815.AbstractPDF
    The blending of polypropylene with lignin derived from chemical wood pulp manufacture makes it possible to prepare optically transparent films (thickness 50-60μm) with acceptable mechanical properties in the absence of a commercial stabilizer. The lignin preparation in the concentration 1-2 wt% possessed the ability to act as a processing stabilizer and as an antioxidant during thermal aging of polypropylene films. A DNA-protective effect of lignin in mice testicular cells and mice peripheral blood lymphocytes against oxidation stress was examined using in vitro experiments. Hydrogen peroxide and visible light-excited methylene blue (MB) were used as DNA damaging agents. The isolated cells were preincubated with lignin before treatment with the oxidative agents. The level of breaks in the DNA was measured by a comet assay. The results showed that preincubation with lignin significantly decreased the level of strand breaks induced by both oxidants in mice lymphocytes and testicular cells.
  • Researchpp 816-824Adejoye, O. D., and Fasidi, I. O. (2009). "Biodegradation of agro-wastes by some Nigerian white-rot fungi,"BioRes. 4(2), 816-824.AbstractPDF
    Three white-rot fungi: Daedalea elegans, Polyporus giganteus, and Lenzites betulina were screened for their lignin degrading abilities on rice straw, maizecob, sawdust of Terminalia superba, and sugarcane bagasse at different time intervals (30, 60, and 90 days). All the fungi demonstrated varying levels of ligninolytic capability with different degrees of lignin degradation in all the fermented substrates. A significant difference (p<0.05) was observed in the mycelia extension of Daedalea elegans grown on the different agro-industrial wastes. D. elegans gave maximum extension of 4.5 cm on sugarcane bagasse. The highest lignin reduction of 92.9% (p<0.05) was recorded in maize cob fermented with Daedalea elegans after 90 days. On the basis of lignocellulosic material degraded, it is concluded that the white-rot fungi offer a better alternative to conventional ways of disposing these waste substances. This paper considers the ability of indigenous white-rot fungi to degrade lignin as a way of using them in effective waste management.
  • Reviewpp 825-834Han, S., Li, J., Zhu, S., Chen, R., Wu, Y., Zhang, X., and Yu, Z. (2009). "Potential applications of ionic liquids in wood related industries," BioRes. 4(2), 825-834.AbstractPDF
    The use of ionic liquids (ILs) has provided a new platform for efficient utilization of wood. In this paper, applications of ILs in wood-related industries are reviewed. First, the dissolution of wood in ILs and its application are described. Then the ILs used for wood preservation and improvement of wood anti-electrostatic and fire-proof properties are illustrated. Finally, “green” wood processing with ILs is discussed. Although some basic studies of ILs, such as their economical syntheses and toxicology are eagerly needed and some engineering problems still exist, research for application of ILs in wood-related industries has made great progress in recent years.
  • Reviewpp 835-849Lu, J., Chorney, M., and Peterson, L. (2009). "Sustainable trailer flooring," BioRes. 4(2), 835-849.AbstractPDF
    Different trailer flooring materials, including wood-based, aluminum, steel, and synthetic plastic floors, were evaluated in accordance with their durability and sustainability to our natural environment. Wood-based trailer flooring is an eco-friendly product. It is the most sustainable trailer flooring material compared with fossil fuel-intensive steel, aluminum, and plastics. It is renewable and recyclable. Oak, hard maple, and apitong are strong and durable hardwood species that are currently extensively used for trailer flooring. For manufacture, wood-based flooring is higher in energy efficiency and lower in carbon emission than steel, aluminum and plastics. Moreover, wood per se is a natural product that sequesters carbon. Accordingly, using more wood-based trailer flooring is effective to reduce global warming.
  • Reviewpp 850-906Hubbe, M. A., Nanko, H., and McNeal, M. R. (2009). "Retention aid polymer interactions with cellulosic surfaces and suspensions: A review," BioRes. 4(2), 850-906.AbstractPDF
    Retention aids can be defined as very-high-mass, water-soluble polymers that are added to cellulosic fiber slurries before the formation of paper in order to improve the efficiency with which fine particles, including cellulosic fines, are retained in the paper product. Optimization of retention aid performance can be a key to achieving efficient and environmentally responsible papermaking objectives. This article reviews various published theories related to retention aid use. Findings related to three main classes of retention aid polymers are considered: cationic acrylamide copolymers (cPAM), anionic acrylamide copolymers (aPAM), and polyethylene oxide (PEO). While many aspects of the interactions of each of these classes of retention aid products can be understood based on colloid chemistry principles, further research is needed in order to more fully bridge the gap between theory and practice.