Volume 13 Issue 3

This research focused on the production of a novel calcium silicate pigment made from pulverized coal fly ash and its application as a coating pigment in a size press for fiber replacement. Improved specific base paper properties of the newsprint was investigated. This novel coated fly ash based calcium silicate (FACS) pigment and conventional precipitated calcium carbonate (PCC) pigment was applied using a cylindrical laboratory coater. When a 4.3 gsm coat weight of FACS was used during the size press application, the brightness increased 10 points, whereas, when the coat weight of FACS was increased to 7.8 gsm, the brightness increased to 21 points as compared to base newsprint sheet; however, FACS brightness was lower than the PCC coated newsprint sheet. Also, there was a significant gain in other newsprint specific base properties when fly ash based pigment was used. This indicated that it is feasible to utilize a novel fly ash based pigment in the size press coating application to replace fiber in order to reduce production cost, improve specific base properties, and reduce environmental pollution. To the authors’ knowledge, this is the first study reporting the application of fly ash as a coating pigment for quality enhancement of newsprint.

The quantitative comparison of essential oils extracted from various parts of Cupressus funebris and Juniperus chinensis was studied. With increased height, the content of essential oils from branches decreased, while the content of essential oils from leaves increased for both species. A maximum amount of essential oils were found in the west and a minimum in the east of branches and leaves for the two species. Moreover, the content of essential oils in trees with a knot was higher than in those without a knot. The order of essential oil content was as follows: leaf > fine root > coarse root > bark > bough > branch > trunk in C. funebris, and leaf > fine root > bark > coarse root > bough > trunk > branch in J. chinensis. The essential oils extracted from various parts of C. funebris and J. chinensis were analyzed by gas chromatography-mass spectrometry. A total of 67, 33, 69, 65, and 69 components were identified from the roots, trunks, barks, branches, and leaves of C. funebris, respectively. A total of 72, 46, 79, 55, and 82 components were identified from the roots, trunk, bark, branches, and leaves of J. chinensis, respectively.

An easy and environmentally friendly strategy is shown for the synthesis of dialdehyde cellulose/silver nanoparticle composites using dialdehyde cellulose as reducing agent through the microwave-assisted hydrothermal method. The effects of the microwave heating time and temperature on the products were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), and thermogravimetric analysis (TGA). The dialdehyde cellulose was found to be an efficient reducing agent for silver ions, and the microwave heating time and temperature played a vital role in the morphologies of the silver nanostructures. The influences of different additional reductants such as ascorbic acid and glucose on the shapes, size-distribution, phase, and crystallinity of the samples were comparatively investigated in detail. This strategy is environmentally friendly, surfactant-free, without any other reducing or stabilizing agent chemicals, and the as-prepared dialdehyde cellulose/silver nanoparticles were more convenient to use in biomedical fields.

The feasibility of utilizing corn straws to produce butanol via fermentation with Clostridium acetobutylicum was evaluated. The supernatant of enzymatically hydrolyzed supernatant of steam-exploded corn straws was used as the raw material. A bacterial strain was selected from Clostridium acetobutylicum zzu-02 and Clostridium beijerinckii zzu-01, which was capable of fermenting the enzymatically hydrolyzed supernatant of steam-exploded corn straw to produce butanol with high yield. The optimal fermentation conditions for the selected strain with enzymatically hydrolyzed supernatant of steam-exploded corn straw were also investigated and they were determined as follows: sugar concentrations in enzymatically hydrolyzed solution of steam exploded corn straws, 57.5 g/L; initial pH, 6.3; the amount of added CaCO₃, 5g/L; the bacterial inoculation concentration to enzymatically hydrolyzed solution, 6%; fermentation temperature, 37 ^oC, the amounts of the added nutritional elements, i.e. yeast extract, CH₃COONH₄, KH₂PO₄, and C₆H₆N₂O, 0.8, 6.0, 0.5, and 0.25 g/L, respectively. Under these conditions, the butanol yield reached 9.88 g/L. Based on the butanol metabolism pathways, supplementation of a small amount of C₆H₆N₂O was found to effectively increase the yield of butanol production.

The objective of this study was to verify the applicability and preliminary results of an ultrasound methodology for the complete characterization of root wood. The tests utilized six species: Swietenia macrophylla, Gallesia integrifólia, Swietenia sp., Schinus molle, Handroanthus heptaphyllus, and Acrocarpus fraxinifolius. The results show expected elastic ratios between properties, indicating that although the properties can differ numerically from roots and other parts of the tree, the orthotropic wood behavior is maintained. The root densities were higher than those reported in the literature for trunk wood, but direct relationships among high density and stiffness or strength properties were not observed. The ultrasound tests allowed 12 elastic constants of root wood to be obtained and were feasible for root dimensions because only one specimen was required.

Inspired by the high adsorption efficiency of aerogels, a thiourea-modified nanocomposite aerogel consisting of nanofibrillated cellulose and chitosan was prepared via a facile method. The prepared novel aerogel was studied by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The adsorptions of the acidic and basic dyes (acid orange 7 and crystal violet) on the aerogel from aqueous solutions were investigated according to the adsorption kinetics and isotherms. The results indicated that a pseudo-second-order kinetic model more accurately described the adsorption process than a pseudo-first-order model, and the adsorption processes of both acid orange 7 and crystal violet on the aerogel were controlled by both inter-facial and intra-particle diffusions simultaneously. The Langmuir isotherm was a better model as compared to Freundlich model for the adsorption of dyes. The aerogel prepared by the facile approach is a promising material for practical applications in acidic and basic dye removal.

Butyric acid is a valuable chemical that has various applications in the chemical, pharmaceutical, food, and biofuel industries. Its bio-fermentation from lignocellulosic materials may be affected by some unwanted substrates that are generated during biomass pretreatment processes. In the present study, the potential inhibitory effects of two phenolic aldehydes (syringaldehyde and vanillin) on butyric acid fermentation by Clostridium tyrobutyricum were evaluated. The toxicity of syringaldehyde and vanillin on cell growth, xylose consumption, and butyric acid production was dosage-dependent. The butyric acid productivity decreased significantly with increasing concentrations of syringaldehyde and vanillin. C. tyrobutyricum demonstrated a broad tolerance to both syringaldehyde and vanillin and only moderate reductions in the maximum cell density were observed with up to 2.4 g L^-1 of syringaldehyde or vanillin in the medium. Both syringaldehyde and vanillin were assimilated by C. tyrobutyricum, and the metabolite products from vanillin caused considerable inhibition of the fermentation.

Chemical changes resulting from the thermal treatment of maple wood (Acer platanoides L.) through various steaming techniques were evaluated. Main wood components were isolated and characterized from the maple wood samples after steaming. Then, the isolated holocellulose and dioxane lignin were analyzed using ATR-FTIR spectroscopy. The effects of an increase in temperature and extension of the steaming period were seen primarily in the holocellulose and extractives contents, and less in the cellulose and lignin components. Certain steaming methods resulted in an increase in chemical composition, while others saw a decrease. The cellulose content of steamed maple wood was not considerably altered; however, the cellulose crystallinity did increase. The slight changes observed in this study can be attributed to several concurrent effects. While the lignin content in steamed maple wood showed only minimal changes, there were several changes in the structure of the lignin macromolecule. Demethoxylation, the decrease in the ratio of syringyl-propane to guaiacyl-propane units, and the formation of new alpha-C=O bonds were also observed. The hydrothermal treatment of wood also resulted in color changes of wood samples; the intensity of the change depended on the intensity of the treatment.

Conversion of lignocellulose into fermentable sugars and other chemicals usually requires multi-step unit operations, such as pretreatment, filtration/washing, and enzymatic saccharification and fermentation, which are the core steps responsible for increased operating expenses. A low-temperature NaOH/urea solution was shown to be an efficient cellulose solvent for overcoming the recalcitrance of lignocellulose by partially or fully converting rigid cellulose I crystallite into the more easily digestible cellulose II structure and by extracting a majority portion of the lignin and xylan from the lignocellulose. Higher yields of fermentable sugars were produced directly from corn stover in one vessel. This one-pot production of fermentable sugars was achieved via a combination process, including pretreatment with low-temperature NaOH/urea solution, pH adjustment, and enzymatic saccharification in a single reactor. This one-pot process liberated 86.3% of glucose and 71.3% of xylose in 24 h at an enzyme loading of 10 FPU/g and solid loading of 5%. Surfactant addition further enhanced enzymatic saccharification. The combination of low-temperature NaOH/urea pretreatment and enzymatic saccharification into a one-pot process is an efficient method for the conversion of lignocellulose into fermentable sugars suitable for conversion into fuels and other chemicals. Further studies related to lignin recovery and economical evaluation will be conducted.

Laminated bamboo with radial (LBR) and tangential (LBT) layered structures was manufactured using heat-treated moso bamboo and phenol-formaldehyde adhesive. The physical, mechanical, and fire-related properties were determined. The results showed that layer structure and heat treatment had an impact on the properties of laminated bamboo. LBR showed good mechanical properties, though heat treatment compromised its integrity somewhat. Heat treatment decreased the lightness and incre6/28ased the green-red index, blue-yellow index, saturation, and total color difference. The samples exhibited changes in two HRR peaks during the combustion process, corresponding to two main release stages for smoke production. Heat-treatment improved the heat rate release (HRR), total heat release (THR), and the effective heat of combustion (EHC) properties, but also they decreased the smoke performances, resulting in higher total suspended particulate (TSP), specific extinction area (SEA), CO, and CO₂ yield. LBR is suggested to be manufactured for possible use as a structural engineering material.