Our peer-reviewed sister journal
BioResources, Volume 7, Issue 3
NOTE: Each current issue of BioResources continues to build as new articles are approved.
Since the introduction of the water footprint concept in 2002, in the context of humankind’s ever-increasing awareness of the valuable global freshwater resources, it has received more and more attention. The application of this relatively new concept has been expected to provide ecological and environmental benefits. For the water-intensive papermaking industry, it seems that water footprint needs to be addressed. The water footprint of cellulosic paper can be divided into three components, including its green water footprint, blue water footprint, and grey water footprint, which may be accounted for by considering the individual contributions of wood or non-wood materials, pulp production processes, effluent discharge to the receiving water bodies, process chemicals and additives, energy consumption, etc. In the literature, the accounting of water footprint during the whole production chain of cellulosic paper is already available, and relevant research findings can provide useful insights into the application of the concept; however, further development of the accounting methodologies is much needed, so that the quantitative and qualitative evaluation of water footprint can be internationally recognized, certified, and standardized. Although there are ongoing or upcoming debates and challenges associated with the concept, its application to papermaking industry may be expected to provide various encouraging possibilities and impacts. PDF
The removal of Cr(VI) from aqueous solutions was studied using a compost generated from carnation flowers waste. The highest percentage of removal achieved (ca. 99 %) was obtained at pH 2.0, using a 10 mg L-1 of Cr(VI) solution, a dose of 10 g L-1 of compost, and with an equilibrium time of 3 hours. Under these conditions, the kinetics and adsorption isotherm were examined varying the initial Cr(VI) concentration from 15 to 200 mg L-1. The maximum sorption capacity at equilibrium (Qm), from the Langmuir model, was found to be 6.25 mg g-1. The evaluation of Cr(VI) removal at pH 2.0 showed a second order kinetics and showed that the process mechanism can be modeled by the “adsorption-coupled reduction” hypothesis. Also, the monitoring of Cr(VI) and total Cr in aqueous solutions showed that Cr(VI) and total Cr were removed from solution, and that part of the Cr(III) was retained on the compost. According to the results, the removal of Cr(VI) with the assayed compost can be explained by the following steps: (i) adsorption of Cr(VI) species onto compost, (ii) Cr(VI) reduction to Cr(III), and (iii) adsorption of part of Cr(III) on the compost. Thus, this study suggests that the carnation flower waste compost can be used as a remediation system for water contaminated with Cr(VI). PDF
Janga, K. K., Øyaas, K., Hertzberg, T., and Moe, S. T. (2012). "Application of a pseudo-kinetic generalized severity model to the concentrated sulfuric acid hydrolysis of pinewood and aspenwood," BioRes. 7(3), 2728-2741.
The yield of monosaccharides after two-stage concentrated sulfuric acid hydrolysis of softwood (Scots pine) and hardwood (trembling aspen) was modeled using a generalized severity parameter with a time-independent rate constant. The severity parameter, which combines the major operating variables acid concentration, temperature, and reaction time in the decrystallization stage into a single reaction ordinate, was successfully used to describe monosaccharide yields after a standardized hydrolysis stage. Conversion of cellulose to glucose demanded a higher severity to reach maximum glucose yields than the conversion of hemicelluloses to their respective monosaccharides, and the conversion of pine demanded a higher severity to obtain maximum monosaccharide yields as compared to aspen. The results indicate that the generalized severity parameter can be a useful tool for the prediction of sugar yields in a two-stage concentrated sulfuric acid hydrolysis process. PDF
A lignosulfonate was prepared from alkali-extracted corn stalk lignin (AEL) by oxidation under mild conditions and sulfomethylation. The oxidized AEL exhibited lower molecular weight, narrower molecular weight distribution, and higher phenolic hydroxyl content than AEL, demonstrating that oxidized AEL was more reactive than those before oxidation. The content of sulfonic groups was significantly increased with the increase in sodium sulphite to AEL ratio, while the content slightly decreased when the ratio was above 1:1. During the sulfomethylation, the content of sulfonic groups increased with time and then achieved a constant level with the increase in time. The content of sulfonic groups reached 1.29 mmol/g, the maximum value, at 5 h and a sodium sulphite to AEL ratio of 1:1. The solubility of AEL was obviously improved by sulfomethylation with the increase in the content of sulfonic groups. The surface activity of AEL was improved after sulfomethylation. The sulfomethylation products exhibited good dispersibility and showed potential for use as a dye dispersant. PDF
Removal of Cd2+, Pb2+, and Ni2+ from aqueous solutions using cellulose-graft-acrylic acid (C-g-AA) hydrogels was investigated. Various factors affecting the adsorption capacity, such as pH, time, initial ions concentration, and competitive ions, were tested. The results showed that the adsorption of hydrogels was very pH dependent, and maximum adsorption was obtained at a pH of 5.0. The adsorption capacities of hydrogels for the heavy metal ions were 562.7 mg/g (Cd2+), 825.7 mg/g (Pb2+), and 380.1 mg/g (Ni2+), respectively. The adsorption behavior can be very well described by the pseudo-second-order kinetic model and the Langmuir isotherm model. The observed affinity order of competitive ions adsorption is Pb2+>Ni2+>Cd2+ in mmol/g. The hydrogels can be regenerated after releasing heavy metal ions and reused three times with 15% loss of adsorption capacity. Scanning electron microscope (SEM) images and Fourier transform infrared spectroscopy (FTIR) spectra before and after ion adsorption on the hydrogels revealed that the complexation between heavy metal ions and carboxyl groups on hydrogels was the main adsorption mechanism. PDF
Paper sludge is a major waste by-product of the paper industry. Its disposal creates serious problems, as approximately 30% of treated sludge is not flammable. In this study, artificial lightweight aggregates (ALWAs) were synthesized from paper sludge by co-sintering with H3BO3. H3BO3acts as a flux to lower the sintering temperature below 900 °C, with co-melting occurring during the procedure. The decomposition gas is sealed within the ALWA during the glassy phase to form a porous structure. Water absorption, apparent porosity, bulk density, compressive strength, and weight loss after rinsing with Na2SO4 were tested to understand the physical properties of the manufactured ALWAs. The optimal method suggested is co-sintering with 18% H3BO3 flux at 890 °C for 30 min. The tested properties mentioned above gave the following results: 4.64 %, 2.77 %, 0.6 g/cm3, 13.2 MPa, and < 0.1 %, respectively. The ALWAs produced in this study have been compared to commercially available lightweight aggregates – Lytag and Arlita – with the examined ALWAs possessing better qualities than Lytag. Water absorption and compressive strength of ALWAs in this study met government requirements of pre-stressed concrete necessary for civil works, and could make useful building material. PDF
Zasadowski, D., Hedenström, E., Edlund, H., and Norgren, M. (2012). "Use of a voith flotation cell for removal of lipophilic extractives and Mn ions from spruce thermomechanical pulping process waters," BioRes. 7(3), 2784-2798.
The effects of a chelating surfactant and different foaming agents on the efficiency of cleaning process waters from a thermomechanical pulp (TMP) mill were studied in a Voith flotation cell. Turbidity measurements and gas chromatography were used to determine the removal extent and characteristics of dissolved and colloidal substances (DisCo). The metal ion content in the process waters before flotation and the metal chelate removal after flotation were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). FiberLab™ equipment was used to characterize changes in the size of fibers present in the process waters. The results indicate that a decrease in turbidity of up to 91% and the removal of 80% of lipophilic extractives in the TMP water could be obtained using a single-stage flotation unit. Furthermore, the foam fraction was within 5% of the initial volume, and 100% of the Mn2+/chelating surfactant complex added to the TMP water was removed. PDF
The heat treatment of softwood (i.e. spruce, pine, fir, and larch) may result in significant colour changes. During this study Scots pine and spruce samples were steamed and analysed for their altered hue and lightness. Treatments included: 0 to 22 days of steaming time at a temperature range of 70 to 100°C. The outcome included a variety of colours between the initial hues and brownish tint. These new colours are similar to that of aged furniture and indoor wooden structures. Consequently, properly steamed softwood may be used to repair historical artefacts and relic furniture. Besides restoration, steamed stocks are excellent sources for manufacture of periodical furniture, where the aged appearance has aesthetical value. Results however, indicated that steaming at a temperature above 90 ˚C has a bleaching effect, i.e. the coloured chemical components formed by moderate steaming may be removed. Furthermore, we observed a linear correlation between lightness and colour hue at all steaming times and temperatures. PDF
Dark brown wood color is a current trend and widely appreciated by consumers in the furniture and decoration markets. Heat treatment is one of the most effective methods to darken wood’s appearance. The influence of steam-heat treatment on color change of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) was investigated within the temperature range from 170 to 230 °C and time from 1 to 5 hours in an air-tight chamber within an atmosphere comprising less than 2 percent oxygen. Saturated steam was used as a heating medium and a shielding gas. The results showed that the chroma difference (△C*) decreased gradually, while the color difference (△E*) and hue difference (△H*) increased with an increase in temperature and length of time. An analysis of variance (ANOVA) and a multi-comparison analysis revealed that the treatment temperature plays a more important role in darkening wood color during the process of steam-heat treatment in comparison with the treatment time. The results suggest that a more desirable wood color can be achieved with the technology of steam-heat treatment. PDF
Lu, Q., Zhang, X.-M., Zhang, Z.-B., Zhang, Y., Zhu, X.-F., and Dong, C.-Q. (2012). "Catalytic fast pyrolysis of cellulose mixed with sulfated titania to produce levoglucosenone: Analytical Py-GC/MS study," BioRes. 7(3), 2820-2834.
Sulfated titania (SO42-/TiO2) was prepared and used for catalytic fast pyrolysis of cellulose to produce levoglucosenone (LGO), a valuable anhydrosugar product. Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) technique was employed in this study to achieve the catalytic fast pyrolysis of cellulose and on-line analysis of the pyrolysis vapors. Experiments were performed to investigate the effects of several factors on the LGO production, i.e. pyrolysis temperature, cellulose/catalyst ratio, TiO2 crystal type, and pyrolysis time. The results indicated that the SO42-/TiO2 catalyst lowered the initial cellulose decomposition temperature and altered the pyrolytic product significantly. Levoglucosan (LG) was the most abundant product in the non-catalytic process, while levoglucosenone (LGO) was the major product in the catalytic process. The maximal LGO yield was obtained at the set pyrolysis temperature of 400 °C, while the highest LGO content was obtained at 350 °C, with the peak area% over 50%. In addition, the SO42-/TiO2 (anatase) was confirmed the best catalyst for the LGO production. PDF
1-octadecanol is known to be a highly effective agglomerating agent for laser toner ink. However, the office waste paper used in the actual production often contains various types of inks. The effect of the offset ink and types of surfactants with different charge characteristics were studied relative to the agglomeration of the laser toner ink under neutral pulping conditions. It was found that the addition of a small amount of the offset ink printed waste paper was beneficial for the agglomeration of the laser toner ink. The optimal percentage of addition is 12.5% to 25%. The offset printed ink had a positive charge of 0.001±0.0005 mEq/g when the offset ink was treated by 70˚C water at neutral conditions. Addition of a proper amount of cationic surfactant was beneficial to improve the agglomeration at any ratio of the mixed laser printed and offset waste papers. When the percentage of offset waste paper was less than 50%, the addition of anionic surfactant and nonionic surfactant was harmful for agglomeration, and there was no significant effect at higher offset content. PDF
The effects of different pretreatment technologies, including sulfuric acid, hot-water, NaOH, and MgCl2 pretreatments, on the fermentation of xylose and glucose to ethanol by Saccharomyces cerevisiae ATCC 24858 and Escherichia coli KO11 were investigated. In this study, cattail was used as the feedstock. The use of aquatic plant cattails to produce biofuel will add value to land and reduce emissions of greenhouse gases by replacing petroleum products. The pretreated biomass first was enzymatically hydrolyzed for 2 days, followed by a 2-day Simultaneous Saccharification and Fermentation (SSF) using S. cerevisiae. The glucose to ethanol yields were approximately 85 to 91% of the theoretical yield for this S. cerevisiae strain. Glucose and xylose released from cattail cellulose and hemicellulose could be fermented to ethanol using E. coli KO11, resulting in approximately 85% of the theoretical ethanol yield using either a Separate Hydrolysis and Fermentation (SHF) process or a SSF process. In order to improve the sugars to ethanol yields, a detoxification process is necessary to remove the inhibitory compounds produced during the acid pretreatment process. Among the four pretreatment methods, the dilute acid pretreatment was found to be superior, and additional research is required to optimize the economics of the overall biorefinery process. PDF
Lignin-based epoxy resin (LER) was prepared from phenolated lignin (PL) and epichlorohydrin (ECH) in the presence of sodium hydroxide. The eucalyptus acetic acid lignin (AAL) was first reacted with phenol in the presence of sulfuric acid to obtain PL. Then, PL was reacted with ECH in aqueous sodium hydroxide to obtain LER. LER was mixed with diglycidyl ether of bisphenol A (E-44) and then cured with triethylenetetramine (TETA). The initial thermal degradation temperature (Td) of the cured epoxy blends decreased with the increase in LER content. The residue ratio at 500 °C of the cured epoxy blends (R500), however, increased with the LER content. The maximum adhesive shear strength of the cured epoxy blends was obtained at 20 wt% of LER. The water absorption of epoxy blends increased with increasing the content of LER. SEM photos showed that increasing the content of LER increased inhomogeneity and porosity of epoxy blends. PDF
Three laccases, functioning in mild acidic, and one in slightly alkaline conditions, were evaluated in order to reduce low-molecular phenolic VOCs of kraft lignins, which could be used in lignin/natural fibers composites. The potential of a sulfhydryl oxidase to catalyze the oxidation of sulfur containing VOCs (thiols) was also tested in combination with the laccase-catalyzed oxidation. In addition, oxidation at alkaline pH at room temperature that may induce polymerization of phenolics in an analogous manner to the laccase-catalyzed reaction was investigated. Enzyme reactivity towards lignin was evaluated as consumption of oxygen in the reaction solution. The effect of treatments on VOC reduction was determined both by sensing (odorimetry) and chemical (TD-GC/MS, SEC) analyses. Laccases, Lcc2, and MaL from Thielavia arenaria and Melanocarpus albomyces, respectively, showed potential in reducing odors. The most promising results were obtained by oxidizing lignin with O2 at alkaline pH. However, the odor threshold values of the main VOC compounds are extremely low, which poses a challenge to VOC reduction. PDF
In this study a number of work-piece variations were evaluated whilst limiting the cutting conditions. Eight wood species controlled at four moisture levels were machined along and across the wood grain. The tool used during cutting was designed to resemble a rip saw tooth with zero rake angle and narrow edge width. Each work-piece variation machined in the cutting tests was subjected to mechanical tests that evaluated bending properties across the grain and shear properties along the grain. The regression model establishes a relationship between the bending properties for cutting forces across the grain, as well as shear properties for cutting forces along the grain. F and R² values show that the elastic properties of the wood in bending and shear have less influence on the cutting forces when compared to the strength and toughness. Additionally, density is seen to have less influence on the cutting force along the grain. This is explained by the tool passing through an unquantifiable proportion of early and latewood fibers from the annual growth rings. Cutting across the grain, the tool is forced to machine through approximately the same proportion of earlywood and latewood fibres. PDF
Chowdhury, Z. Z., Zain, S. M., Khan, R. A., Rafique, R. F., and Khalid, K. (2012). "Batch and fixed bed adsorption studies of lead (II) cations from aqueous solutions onto granular activated carbon derived from Mangostana garcinia shell," BioRes. 7(3), 2895-2915.
The feasibility of granular activated carbon (GAC) derived from Mangostene (Mangostana garcinia) fruit shell to remove lead, Pb2+ cations was investigated in batch and fixed bed sorption systems. Batch experiments were carried out to study equilibrium isotherms, kinetics, and thermodynamics by using an initial lead (Pb2+ ions) concentration of 50 to 100 mg/L at pH 5.5. Equilibrium data were fitted using Langmuir, Freundlich, and Temkin linear equation models at temperatures 30°C, 50°C, and 70°C. Langmuir maximum monolayer sorption capacity was 25.00 mg/g at 30°C. The experimental data were best represented by pseudo-second-order and Elovich models. The sorption process was found to be feasible, endothermic, and spontaneous. In column experiments, the effects of initial cation concentration (50 mg/L, 70 mg/L, and 100 mg/L), bed height (4.5 cm and 3 cm), and flow rate (1 mL/min and 3 mL/min) on the breakthrough characteristics were evaluated. Breakthrough curves were further analyzed by using Thomas and Yoon Nelson models to study column dynamics. The column was regenerated and reused consecutively for four cycles. The result demonstrated that the prepared activated carbon was suitable for removal of Pb2+ from synthetic aqueous solution using batch, as well as fixed bed sorption systems. PDF
To investigate the effects of different ethylene vinyl acetate (EVA) contents on the performance of wood plastic composites (WPCs) made from poplar wood flour (PWF) and high density polyethylene (HDPE), physical properties tests, mechanical properties tests, and scanning electron microscope (SEM) tests were employed. The thermal stability and functional groups of PWF treated by EVA were evaluated by thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Fourier transform infrared spectroscopy (FTIR) , respectively. The results showed that the hardness, water uptake, and thickness swelling of the WPCs was reduced with increasing content of EVA. The MOR and tensile strength of the WPC treated by 15% EVA content were enhanced by 17.48% and 9.97%, respectively, compared with those of the WPC without EVA. TGA results showed that the thermal stability of PWF treated by EVA was improved. FTIR analysis indicated that PWF was reacted and coated with EVA. SEM results showed that gaps and voids hardly existed in the sections of the WPCs treated by EVA. This research suggests that the flexibility and mechanical properties of WPCs could be improved by adding EVA. The best condition of EVA content could be 15%. PDF
Maximizing recovery and characterization of extractable proteins from secondary paper sludge is essential to explore the potential value from utilization of readily available waste products from pulp and paper mills. A multistep physicochemical recovery process was used, involving optimum alkaline solubilization of protein into an aqueous phase followed by augmented physical disruption of cell membranes. The final precipitation of solubilised protein was carried out using different acidic media. The optimization studies revealed that the best removal of intercellular contents from sludge can be achieved at pH 12; at this level, up to 88% of available protein is solubilised into the aqueous phase. Of all the precipitating agents used, sulphuric acid proved most effective by recovering 90% of disrupted protein. The combined effect of french press and sonication techniques resulted in significant improvement in the overall yield of recovered sludge protein (RSP). The characterization studies showed the presence of common and essential amino acids in RSP in significant quantities; it also showed that the recovery process can significantly reduce or eliminate heavy metals present in the sludge. The molecular weights (MW) of extractable proteins were determined by PAGE, and it was observed that RSP contains both low and high MW fractions. PDF
Abdullah, C. K., Jawaid, M., Abdul Khalil, H. P. S., Zaidon, A., and Hadiyane, A. (2012). "Oil palm trunk polymer composite: Morphology, water absorption, and thickness swelling behaviours," BioRes. 7(3), 2948-2959.
In this research, impregnated oil palm trunks (OPT) and polymer composites were prepared from a combination of dried oil palm trunks with phenol formaldehyde (PF) and urea formaldehyde (UF) resin in different resin percentages using an impregnation method. Time of impregnation was a parameter used to control the percentage of resin content in the oil palm trunks. These studies investigated the effect of resin content and types of resin on the physical properties of impregnated OPT. Water absorption tests revealed that OPT polymer composite with 75% PF resin loading had increases of 21% and 26% for OPT polymer composites with 75% UF resin loading. The thickness swelling of OPT polymer composites with 75% PF resin loading exhibited the lowest value of 3.30% as compared with OPT polymer composite with 75% UF resin loading, which exhibited a value of 4.30%. The dimensional stability of the OPT polymer composites with the highest resin loading was slightly lower when compared to rubberwood. Scanning electron micrographs show that PF resin placement in OPT polymer composites was better, and resin penetration retained the original dried OPT structure. PDF
The feasibility of using naturally extracted solutions as wood preservative chemical was tested. Extracts extracted from mimosa (Acacia mollissima Willd.), quebracho (Shinopsis lorentzii Griseb.), and Pinus brutia Ten. bark were used to treat sapwood of Scotch pine (Pinus sylvestris L.), beech (Fagus orientalis L.), and poplar (Populus tremula L.) at two different retention levels (6% and 12% weight/weight) against the subterranean termite Reticulitermes grassei Clement (Blattodea: Rhinotermitidae). The lowest mass loss and highest termite mortality rates were recorded for mimosa and quebracho extract treated woods at the 12% concentration level. Pine bark extract seemed to be ineffective as a wood preservative chemical even at the highest retention level. The results suggest that mimosa and quebracho extracts can be utilized as an environmentally-sound alternative wood preservative chemicals for indoor applications against Reticulitermes grassei. PDF
Rathke, J., Sinn, G., Harm, M., Teischinger, A., Weigl, M., and Müller, U. (2012). "Effects of alternative raw materials and varying resin content on mechanical and fracture mechanical properties of particle board," BioRes. 7(3), 2970-2985.
Particle boards were produced from different types of wood particles, i.e. spruce, recovered particles, willow, poplar, and locust. Effects of raw material, as well as varying resin content on mechanical and fracture mechanical properties were investigated. For the analysis of mechanical properties, specific fracture energy, stress intensity factors, and the industrial European standard methods internal bond strength according to EN 319 and bending strength according to EN 310 were used. The total fracture energy was measured, and the stress intensity factor was calculated by means of data achieved through finite element simulations. Results of the fracture energy analysis were compared to internal bond strength (IB) and bending strength. While IB and the modulus of elasticity (MOE) showed a high variability, data scattering for fracture energy tests and modulus of rupture (MOR) were smaller, which are due to significant differences between the resin contents of the various board types. PDF
Han, G., Cheng, W., Manning, M., and Eloy, P. (2012). "Performance of zinc borate-treated oriented structural straw board against mold fungi, decay fungi, and termites - A preliminary trial," BioRes. 7(3), 2986-2995.
The performance of zinc borate (ZB)-treated oriented structural straw board (OSSB) against mold fungi, decay fungi, and termites was examined in standard laboratory evaluations. OSSB was fabricated with split wheat straw strands and diphenylmethane diisocyante (pMDI) resin. The ZB was added during panel manufacture to achieve preservative levels (wt.%) of 1.0%, 1.5%, 2.0%, and 3.0%. It was observed that after a four-week exposure to mold fungi all samples had some mold coverage, but the coverage on the ZB-treated samples was significantly lighter compared to the untreated OSSB. Decay test showed that the weight losses of ZB-treated OSSB blocks at 1.0% and 1.5% levels were significantly reduced compared to the untreated OSSB and solid wood controls, indicating superior performance of ZB-treated OSSB against decay fungi. The termite mortality indicated that none of the termites were alive at the conclusion of the test for ZB-treated OSSB. The results from these specific laboratory studies demonstrated that ZB retentions of 1.5% and greater provide performance against decay fungi and termites for OSSB panels. In addition, untreated OSSB has high susceptibility to mold due to the chemical features of wheat straw and incomplete removal of kernels. PDF
Wood strands either prepared in the laboratory or from a manufacturing plant were assessed for their ultimate tensile strength, tensile MOE, bending strength, and bending stiffness, and then near infrared spectroscopy was utilized for prediction. The ability to predict ultimate tensile strength and stiffness was generally weaker than bending strength and stiffness, perhaps due to the homogeneous distribution of stresses that occur within the strand during 3-point bending. Prediction of ultimate tensile strength and elasticity of plant based strands were generally weak due to imperfections in the strands that originate during biomass breakdown; however, for laboratory strands, prediction of tensile strength and stiffness was moderate/better. The modulus of elasticity for strands under bending exhibited the strongest correlation (R2 = 0.76). Principal component loadings were assessed, and it was found that the cellulose crystalline- and semi-crystalline-associated wavelengths were most important in predicting the stiffness for both tensile and bending forces; however, the influence of lignin-associated wavelengths increased in importance when predicting bending strength, and it was hypothesized that this was attributable to the plastic response of lignin above the proportional limit in the stress-to-strain curve. This study demonstrates the potential of near infrared spectroscopy to monitor the biomass quality prior to composite manufacture. PDF
Cellulose was treated in ethylene glycol with p-toluene sulfonic acid monohydrate as a catalyst at different temperatures. At the highest treatment temperature (150 °C) liquefaction of wood pulp cellulose was achieved and was dependant on cellulose polymerization degree (DP). Furthermore, the rate of amorphous cellulose weight loss was found to increase with cellulose degree of polymerization, while the rate of crystalline cellulose weight loss was reciprocal to the size of the crystallites. The cellulose degradation was studied by monitoring of the molecular mass decrease by size-exclusion chromatography. It was revealed that microcrystalline cellulose degrades via a ‘quantum mode’ mechanism, while the degradation of Whatman filter paper no 1. and cotton linters proceeded randomly and were partly dependent on the starting polymerization degree, crystallinity, and treatment temperature. The kinetics of cellulose degradation in heterogeneous media was described by means of a one-stage model, characterised by the consumption of glycosidic bonds in amorphous and crystalline cellulose regions until the levelling-off degree of polymerization is reached. PDF
Compression wood is commonly found in Masson pine. To evaluate the mechanical properties of the cell wall of Masson pine compression and opposite wood, nanoindentation was used. The results showed that the average values of hardness and cell wall modulus of elasticity of opposite wood were slightly higher than those of compression wood. With increasing age of the annual ring, the modulus of elasticity showed a negative correlation with microfibril angle, but a weak correlation was observed for hardness. In opposite and compression wood from the same annual ring, the differences in average values of modulus of elasticity and hardness were small. These slight differences were explained by the change of microfibril angle (MFA), the press-in mode of nanoindentation, and the special structure of compression wood. The mechanical properties were almost the same for early, transition, and late wood in a mature annual ring of opposite wood. It can therefore be inferred that the average modulus of elasticity (MOE) and hardness of the cell walls in a mature annual ring were not being affected by cell wall thickness. PDF
Xylo-oligosaccharides (XOS) are reported to have beneficial health properties, and they are considered to be functional food ingredients. Corn fiber separated from distillers dried grains with solubles (DDGS) could be a valuable feedstock for XOS production. The objective of this study was to determine the efficacy for autohydrolysis to produce XOS using fiber separated from DDGS and to determine the optimum temperature for XOS production. Corn fiber was treated with deionized water in a Parr-reactor, at temperatures ranging from 140 to 220 °C to produce XOS. The maximum total yield of XOS in the solution was 18.6 wt% of the corn fiber at 180 °C. PDF
Heijnesson Hultén, A., Basta, J., Samuelsson. M., Greschik, T., Ander, P., and Daniel, G. (2012). "Aspects on bleaching and tempo-mediated oxidation of wheat straw pulp fractions," BioRes. 7(3), 3051-3063.
This study outlines research concerning wheat straw fines, including their impact on pulp bleachability, their modification by chemical means, and their use as a dry strength enhancer in a paper application. Results show that primary fines constituting about 23% of the whole wheat straw pulp had a large negative impact on pulp bleachability. The differences in response to bleaching were due to the different properties of the fines, i.e. higher kappa number, higher metal ion content, lower brightness, and lower viscosity compared to that of fibers. It was also shown that the fines fraction is more difficult to oxidize and does not reach as high fiber charge levels as that of the other fractions. However, at a dosage of ≥ 3 mmol hypochlorite/g it was possible to prepare nanofibers from wheat straw fines that showed a good strength-enhancing effect in a paper product. The fact that removal of fines from wheat straw pulps by fractionation improves bleachability and also drainage properties at the same time, while simultaneously the fines can be modified and used as a strength enhancer, is very interesting when evaluating the potential of this type of annual plant as a source for production of different paper products. PDF
Cellulose nanofibril/phenol formaldehyde (CNF/PF) composite films with high work of fracture were prepared by filtering a mixture of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized wood nanofibers and water-soluble phenol formaldehyde with resin contents ranging from 5 to 20 wt%, followed by hot pressing. The composites were characterized by tensile testing, dynamic mechanical analysis, scanning electron microscopy, atomic force microscopy, thermo-gravimetric analysis, and moisture/water absorption. Neat CNF films had tensile stress and Young’s modulus of 232 MPa and 4.79 GPa, respectively. PF resin was found to be well dispersed in the composites, although the resin increased the roughness of the film surfaces. Hygroscopic capacities of the composites were dramatically reduced, as compared to neat films, in both high humidity environments and when soaked in water. The composites exhibited slightly reduced tensile strength with modestly increased storage modulus compared to neat CNF films. Remarkably, the work of fracture ranged from 20 to 27 MJ/m3, making these films among the toughest reported for cellulose nanocomposites. PDF
Huang, S., Wang, B. J., Lu, J., Lei, Y., Dai, C., and Sun, X. (2012). "Characterizing Changbai larch through veneering. Part 2: Effect of diameter at breast height and radial growth," BioRes. 7(3), 3076-3092.
This is the second part of a large research initiative aimed at characterizing Changbai larch (Larix olgensis Henry) for veneer and high-valued product potential. The objective of this work was to investigate the effect of the tree growth characteristics, particularly diameter at breast height (DBH) and radial growth from pith (or peeler core) to bark on clear wood and veneer properties. A population of 36 trees was chosen and classified into three DBH classes, namely 20, 25, and 30 cm, and crosscut into six segments each along the vertical stem. With the entire veneer ribbon peeled from the pith to bark for each segment, the effect of sapwood and heartwood on wood properties was revealed. The tree DBH and height were moderately and positively correlated. The tree DBH significantly affected properties of both clear wood and veneer in a similar pattern. For the larch veneer population, veneer mean ultrasonic propagation time (UPT) and density decreased but veneer mean dynamic modulus of elasticity (MOE) increased from the heartwood to sapwood or from the pith to bark. Among the three DBH classes, the 25 cm DBH yielded the highest mean veneer density and MOE, followed by the 20 cm DBH and 30 cm DBH. This was found to be caused by the radial evolution of veneer properties from the pith to bark in combination with the variation of veneer yield and stem position. PDF
In Chile the amounts of wood sawdust, shavings, and chips available is around 2.72 million, 340 thousand, and 4.25 million m3/year, respectively, and about 30% of this material is employed in the manufacture of particleboards. Two types of particleboards were made from wood residues as moisture-resistant particleboards, and the main goal was to meet the requirements for P3 moisture resistance according to the European Standard EN 312. Five mats of each type were pressed without stops in a 30 cm diameter electrically heated hot press at 180°C for 3.5 min. Target board density was 680 kg/m3 (T1) and 720 kg/m3 (T2), mat moisture was 10%, resin dosage applied was 6%, and board thickness was 15 mm for both boards (0.5 x 0.5 m). Samples were designated as T1 and T2, on which both physical and mechanical tests were conducted. Density, moisture content, thickness swelling, and water absorption were measured. Mechanical tests included internal bond before and after cyclic test, as well as fire retardancy. The analysis of the high resolution images allowed us to ensure that there was no gap between the veneer and the particleboard; therefore it can be concluded that there was no adherence loss. Results for all tests showed that both boards met all the P3 standards for moisture resistant non-structural board for use in humid conditions. PDF
In this study, the bending strength and stiffness of laminated veneer lumber (LVL) produced from beech (Fagus orientalis L.), poplar (Populus x euramericana I-214), and eucalyptus (Eucalyptus grandis W. Hill ex Maiden) wood using urea formaldehyde (UF), melamine urea formaldehyde (MUF), and phenol formaldehyde (PF) adhesives were determined. The tests were conducted in the flatwise and edgewise directions. The modulus of rupture (MOR), modulus of elasticity (MOE), specific modulus of rupture (SMOR), and specific modulus of elasticity (SMOE) were calculated. Variance analysis of the bending properties indicated that the effects of the species of tree, the direction of the load, and the type of adhesive were statistically significant. However, according to variance analysis of the SMOR, the effects of the type of adhesive were not significant. The results showed that the type of adhesive did not influence the bending properties of laminated veneer lumber. It can be stated that the differences among groups were due to differences in their densities. The direction of the load and the species of the tree had significant effects on the bending properties. PDF
Wheat straw pulp was mechanochemically processed in a PFI mill in order to improve the effect of laccase/xylanase system (LXS) treatment before bleaching. The delignification and bleachability of the prepared pulp were investigated. The delignification of the prepared pulp could be enhanced with the mechanochemical processing (refining) and LXS treatment. The delignification was increased by 29.8% with refining 7000 revolutions and 5 IU/g enzyme dosage. The LXS treatment after the mechanochemical process could save 28.6% effective usage of chlorine in the subsequent hypochlorite bleaching process, compared with the traditional bio-bleaching. The crystallinity of cellulose was increased by the co-treatment with mechanochemistry and LXS treatment. This result was further supported by the observations from SEM. This co-treatment with mechanochemistry and bio-treatment enhanced the delignification and bleachability of pulp. PDF
Absorbent-grade paper is a highly specialized product due to introduction of certain special characteristics, namely high water absorbency, castor oil penetration (COP), and porosity. Water absorbency is affected by the radius of capillaries within the paper. Likewise the COP is affected by pulp beating and by the degree of collapse of the paper structure during sheet pressing. Using 4% NaHCO3 solution during manufacturing of absorbent grade paper not only improves all the three basic properties, but it also mitigates the cost of absorbent grade paper by US$ 4.07 per metric tonne. Fibers come closer to each other during sheet making as a result of increased surface tension forces due to mixing of NaHCO3 in tap water. PDF
Wang, Y., Chang, J., Morrell, J. J., Freitag, C. M., and Karchesy, J. J. (2012). "An integrated approach using Bacillus subtilis B26 and essential oils to limit fungal discoloration of wood," BioRes. 7(3), 3132-3141.
Bacillus subtilis and essential oils have been explored separately for their ability to limit colonization by wood stain and mold fungi, but neither approach has been completely effective. One alternative strategy would be to combine the bacterial biocontrol with one or more natural products extracts. In this report, the ability of combinations of B. subtilis B26 and 20 essential oils to limit fungal stain was explored on Douglas-fir sapwood wafers under controlled laboratory conditions. A number of extracts markedly improved the anti-fungal activity of B. subtilis B26, including 0.25% myrtlewood oil, 0.5% orange oil, 0.5% lime oil, and 1% Leyland cypress needles oil, which yielded improvements by 2 to 8 times. However, none of the combinations completely protected the wood from fungal attack. The results illustrate the difficulties associated with controlling the diverse array of organisms that can colonize freshly cut wood. PDF
Biomaterials from olive tree pruning are an abundant agricultural residue in various Mediterranean regions. A suggested use of this residue is its separation in a main fraction (trunks and stems with diameter > 1 cm) and a residual fraction (leaves and stems with diameter 1 < cm), using biorefinery procedures. The main fraction is cooked with ethanol, giving rise to a pulp, which can be used either in paper or in bioethanol production if before pulping the main fraction is subjected to a hydrothermal treatment. Pulping with 70% ethanol concentration, 185 °C for 80 min resulted in a pulp with a yield of 46.30% and a content of holocellulose, α-cellulose, and lignin of 77.17%, 62.49%, and 21.73%, respectively. The paper sheets obtained had a breaking length of 1168 m, a burst index of 0.44 kN /g, a tear index of 2.25 mN.m2/g, and a brightness of 43.66%. The pulp converted into bioethanol (by simultaneous hydrolysis and fermentation) achieved a conversion of 70 g bioethanol/100 g potential bioethanol. The residual fraction of olive tree prunings was subjected to combustion to produce thermal energy. The heating value was 18700 kJ/kg, the flame temperature range was 1094 to 2013 ºC, and the dew point temperature range of the flue gases was 47 to 53 °C. PDF
Nocetti, M., Brunetti, M., Ducci, F., Romagnoli, M., Rozenberg, P., and Santi, F. (2012). "Phenotypic correlations among wood properties and growth in wild cherry plantations," BioRes. 7(3), 3160-3174.
Italy is one of the major users of cherry wood (Prunus avium L.), and its cultivation has been increasing since the early nineties, together with studies aimed at improving genotypes, with a selection usually based on growth, stem form, vigor, and tree adaptation. Here, the phenotypic correlations between growth rate and the physical and mechanical properties of wood are investigated in two wild cherry plantations. X-ray microdensitometry was also applied to analyze the age-age correlations of wood density. It was shown that growth rate did not affect wood properties, and density was confirmed to be the trait that best represents the main properties of wood. The absence of relationships between wood density and growth rate was confirmed by densitometric analysis, although an increase of wood density with an increase of ring width was detected for very narrow rings (less than 3 mm wide). The average density at age 7 to 8 was observed to be highly correlated (r > 0.90) to the average density of a 19-year-old tree, allowing reliable estimation of the wood properties of older trees by early investigation of young trees. PDF
Tay, T., Erdem, M., Ceylan, B., and Karagöz, S. (2012). "Adsorption of methylene blue from aqueous solution on activated carbon produced from soybean oil cake by KOH activation," BioRes. 7(3), 3175-3187.
This study presents the adsorption behavior of the methylene blue (MB) dye onto the activated carbon produced from soybean oil cake by chemical activation with KOH at 800 °C. The adsorption isotherms, kinetic models, and thermodynamic parameters of the adsorption were studied. The Langmuir isotherm showed a better fit than the Freundlich isotherm. The adsorption rate was described by pseudo-second-order kinetics. The negative values of ΔG° and the positive values of ΔH° indicate that the adsorption of MB was favored and endothermic. PDF
López, J. P., Méndez, J. A., Espinach, F. X., Julián, F., Mutjé, P., and Vilaseca, F. (2012). "Tensile strength characteristics of polypropylene composites reinforced with stone groundwood fibers from softwood," BioRes. 7(3), 3188-3200.
The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW) is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP) composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composite material. Two mixing extrusion processes were evaluated, and the use of a kinetic mixer, instead of an internal mixer, resulted in longer mean fiber lengths of the reinforcing fibers. On the other hand, the accessibility of surface hydroxyl groups of stone groundwood fibers was improved by treating the fibers with 5% of sodium hydroxide, resulting in a noticeable increase of the tensile strength of the composites, for a similar percentage of coupling agent. A new parameter called Fiber Tensile Strength Factor is defined and used as a baseline for the comparison of the properties of the different composite materials. Finally the competitiveness of stone groundwood / polypropylene / polypropylene-co-maleic anhydride system, which compared favorably to sized glass-fiber / polypropylene GF/PP and glass-fiber / polypropylene / polypropylene-co-maleic anhydride composite formulations, was quantified by means of the fiber tensile strength factor. PDF
Agglomeration phenomena of two mixed xerographic toners were investigated using 1-octadecanol as the agglomeration agent and a cationic surfactant as the co-agglomeration agent. One toner carrying no surface charge agglomerated well under most conditions, while the other toner carrying a negative surface charge performed worse. It was found that when mixing these two toners together during pulping and when using 1-octadecanol as the agglomeration agent alone, there was an additive effect on agglomeration. On the other hand, addition of a small amount of cationic surfactant dramatically enhanced the mixed toner agglomeration efficiency and generated an obvious synergistic effect. The particle number after agglomeration was significantly reduced, and the particle size was greatly increased compared to the single toner agglomeration. The optimal amount of the cationic surfactant was close to the optimal cationic surfactant demand of the negatively charged toner. Based on these findings it can be recommended that the cationic surfactant should be added during agglomeration of the mixed office waste paper, and its optimal dosage needs to be chosen to reach the best performance. PDF
Copper/carbon core/shell nanoparticles (CCCSNs) recently have been introduced as an industrial material. In this paper, composites based on high density polyethylene (HDPE), bamboo fiber, CCCSNs, and coupling agent (MAPE) were prepared by melt compounding. The influence of CCCSN content on the resulting composites’ mechanical, biological resistance, and thermal properties was investigated. It was found that CCCSNs within the carbon black matrix were processed well with bamboo fiber-plastic blends through mixing and injection molding. The materials enhanced composite strength and modulus-related properties. Composites with CCCSNs and natural fibers reduced heat capacity and thermal diffusivity. Composites with CCCSN materials also enhanced termite and mold performance. Thus, the material can be used as additive for plastics and other polymers to modify strength properties, biological resistance (e.g., mold and stain), and thermal conductivity properties. PDF
Lignocellulosic biomass is considered the most abundant renewable resource that has the potential to contribute remarkably in the supply of biofuel. Previous studies have shown that chemical pretreatment prior to anaerobic digestion (AD) can increase the digestibility of lignocellulosic biomass and methane yield. In the present study, the effect of rice straw pretreatment using ammonium hydroxide (NH3•H2O) and hydrogen peroxide (H2O2) on the biogasification performance through AD was investigated. A self-designed, laboratory-scale, and continuous anaerobic biogas digester was used for the evaluation. Results showed that the contents of the rice straw, i.e. the lignin, cellulose, and hemicellulose were degraded significantly after the NH3•H2O and H2O2 treatments, and that biogas production from all pretreated rice straw increased. In addition, the optimal treatments for biogas production were the 4% and 3% H2O2 treatments (w/w), which yielded 327.5 and 319.7 mL/gVS, biogas, respectively, higher than the untreated sample. Biogas production from H2O2 pretreated rice straw was more favorable than rice straw pretreated with same concentration of ammonia, ranking in the order of 4% ≈ 3% > 2% > 1%. The optimal amount of H2O2 treatment for rice straw biogas digestion is 3% when economics and biogas yields are considered. PDF
Peroxidase catalyzes the oxidation of various electron donor substrates such as phenol and aromatic amines in the presence of hydrogen peroxide. In this study, peroxidase was purified 164-fold from the leaves of Moringa oleifera L. with a recovery of 28% by ammonium sulphate precipitation, DEAE-cellulose column chromatography, Sephadex G-200 column chromatography, and Con-A column chromatography. SDS-PAGE showed a polypeptide band with molecular weight of 43 kDa. The enzyme was found to be a single subunit in nature. The purified enzyme displayed optimum activity at pH 6.0 and at a temperature of 50 °C with a Km value of 0.2335 mM for guaiacol as best substrate. It is a glycoprotein that contains 9.05% sugar as estimated by the phenol sulfuric acid method. Some ions (Ni2+, Pb2+, Zn2+, Al3+, Mg2+, Cu2+, Co2+, and Cd2+) exhibited low inhibitory effect while Fe2+, Fe3+, and Hg2+ exhibited strong inhibitory effects. EDTA markedly inhibited the peroxidase activity. PDF
Turkey annually produces 26 million tons of vegetables and is the third-biggest vegetable producer. After harvest, the waste of vegetable stalks lacking of economic value is burnt or left in the fields, causing environmental pollution. The aim of this study was to examine bioethanol production of a mixture of tomato, pepper, and eggplant stalks using an alternative chemical, sodium borohydrate (NaBH4) in a chemical pretreatment step. Both steam-exploded (SE) and dry-milled (DM) stalks were chemically pretreated and enzymatically hydrolyzed in this study. Results showed that SE stalks had better enzymatic digestibility compared to DM. NaOH treatment removed the highest amount of lignin (17.1%; SE, 2%, 90 min) but also glucose (21.5%; SE, 2%, 90 min) from the structure. On the other hand, NaBH4 removed the highest lignin in proportion to glucose for both SE and DM samples. Enzymatically hydrolyzed stalks gave the highest sugar yields of 30.1% (o.d.-dry matter) for the SE sample when it was pretreated with 2% NaOH for 30 min. PDF
Dashti, H., Shahverdi, M., Taghiyari, H. R., Salehpur, S., and Heshmati, S. (2012). "Effects of steaming and microwave pretreatments on mass transfer characteristics of Aleppe oak (Quercus infectoria)," BioRes. 7(3), 3262-3273.
In this research, effects of steaming and microwave pretreatments on the mass transfer properties of never-dried Q. infectoria were investigated. Specimens at green moisture content were exposed to microwaves of frequency 2450 MHz for 10 minutes. The pre-steaming was performed at a temperature of 160°C for 1 hour under a pressure of 2 to 3 bars. Air permeability values were measured to be 4.8 and 4.9 ( × 10-16m3 m-1) in the sapwood and heartwood, respectively. Results showed a significant general increase in the air permeability and diffusion coefficients in the pretreated sapwood specimens. The presence of tyloses in the heartwood prevented the penetration of steam to the inner parts of the specimens, resulting in the diffusion coefficient remaining constant. The pressure gradient caused by the microwave heating resulted in the distortion of the tyloses structure in the heartwood, thus resulting in a significant increase in the air permeability. It may be concluded that the presence of tyloses has a significant effect on the final impact of either of the pretreatments. PDF
The high silica content of wheat straw is an important limiting factor for straw pulping. High silica content complicates processing and black liquor recovery, wears out factory installations, and lowers paper quality. Each section of wheat straw has different cells and chemical compositions and thus different silica content. In this work, the silica content of balled straw samples were examined according to their physical components, including internodes, nodes, leaves (sheath and blade), rachis, grain, other plant bodies, and other plant spikes. Mass distribution of silica was determined by a dry ashing method. Half (50.90%) of the silica comes from leaves, and its mechanical separation will reduce the silica content in wheat straw pulp significantly. Destroying silica bodies by sonication will increase the strength properties of straw pulp. PDF
In the present work, the production of dissolving pulp from fast growing 30-year-old local plantation aspen was investigated. The mill-made chips of aspen (Populus deltoides) after being pre-hydrolyzed with water at 170 ºC, were pulped with a soda-AQ pulping process at a kappa number of 15. It was further delignified to a kappa number of 9.2 using a single stage oxygen delignification and bleached with a D0ED1 bleaching sequence at different kappa factor. The pulp viscosity was increased at higher brightness and similar α-cellulose when the kappa factor was increased from 0.30 to 0.45 in the D0 stage of the D0ED1 bleaching sequence, due to higher lignin dissolution and more fiber purification. The results showed that pre-hydrolyzed soda-AQ dissolving pulp can be made from Populus deltoides at a high level of alpha-cellulose content and acceptable levels of brightness and viscosity by means of proper control and optimization of pre-hydrolysis, pulping, and oxygen pretreatment conditions, and an optimized DED bleaching sequence. PDF
Mengeloglu, F., and Karakuş, K. (2012). "Mechanical properties of injection-molded foamed wheat straw filled HDPE biocomposites: The effects of filler loading and coupling agent contents," BioRes. 7(3), 3293-3305.
This study investigated the effect of filler loading and coupling agent contents on the densities and mechanical properties of injection-molded foamed biocomposites. Biocomposite pellets were manufactured using wheat straw flour, maleic anhydrite grafted polyethylene (MAPE), paraffin wax, and high-density polyethylene (HDPE) with an extrusion process. Pellets and the chemical foaming agent (azodicarbonamide) were dry-mixed and foamed in an injection-molding machine. Densities and mechanical properties of the foamed biocomposites samples were measured and analyzed using central composite design (CCD). The results showed that both filler loading and coupling agent contents affected the density and mechanical properties of foamed biocomposites. Densities in the range of 0.57 to 0.81 gr cm-3 were achieved. Best results were obtained when less than 20% wheat straw flour and 1% coupling agent content were used. The flexural modulus and tensile modulus of foamed biocomposites were improved with increasing filler loading. However, flexural strength, tensile strength, elongation at break, and impact strength values were diminished. The tensile strength of the biocomposites was positively affected by CA contents, but other mechanical properties were not affected by it. Overall, injection molded foamed biocomposites with moderate mechanical properties were produced. PDF
Relationships between the coefficient of thermal conductivity (CTC) and the strength properties of wood were investigated. Small clear test specimens were prepared from beech, fir, and pine wood. CTC values of the test specimens were measured based on the ASTM C 1113-99 hot-wire method. Wood density and some mechanical properties were then determined according to related ISO standards. In order to designate relationships between the CTC and mechanical properties, linear regression analysis was performed. Significant linear correlations were found between the CTC and the specific gravity, the modulus of rupture, the modulus of elasticity, and the impact bending strength of the wood from all tree species. However, there was a weak and non-significant relationship between the CTC and the compression strength of the specimens from each tree species. As a consequence, the CTC has a considerable potential in nondestructive evaluation of wood density and strength. However, the reciprocal correlations among the MC-strength, MC-CTC, temperature-strength, and temperature-CTC appear to be most significant limitations for using CTC as a NDE method for wood. Further detailed investigations are needed. PDF
The use of fillers tends to reduce paper strength, which can limit their application. Therefore research on filler modification is of significant importance in order to overcome this limitation. In this paper, precipitated calcium carbonate (PCC) was modified by starch, sodium stearate, and the starch cross-linking agent sodium hexametaphosphate. The purpose of this research is to provide useful references to the industrial application of modified precipitated calcium carbonate (PCC). Modified precipitated calcium carbonate (PCC) was characterized by particle size analyzer and scanning electron microscope (SEM). The analysis showed that the particle size of the modified PCC was significantly increased versus the control. The morphology of modified PCC also greatly changed. The influence of modified and unmodified PCC filled paper on paper physical performance was studied. The experimental results showed that at the same ash content, modified PCC filled paper compared with unmodified PCC filled paper had higher brightness, lower opacity, and higher physical strength. The impact of modified and unmodified PCC on stock retention and the comparison between modified and unmodified PCC were investigated. The experimental results showed that the stock filled with modified PCC had better retention compared to those filled with unmodified PCC. PDF
Effects of cold oxygen plasma treatment on activating the surface of poplar veneers and improving its wettability were investigated. The veneers were treated with cold oxygen plasma for 1, 3, 5, 7, and 9 min, and aged in air for 1, 3, 7, 14, 21, and 28 days. The dynamic adhesive wettability of veneers was assessed using the contact angle, K-value analysis, and surface free energy. The shear strength of three-layer panels produced from untreated and cold oxygen plasma treated veneers was examined. The results showed that the wettability of veneer was significantly improved after cold oxygen plasma treatment, leading to the enhancement of shear strength of panels. The optimized treatment time should be 7 min. Aging effect of treated veneers showed that the veneer surface wettability degraded within the first 7 days and thereafter changed slightly. PDF
Olivella, M. À., Fiol, N., De la Torre, F., Poch, J., and Villaescusa, I. (2012). "A mechanistic approach to methylene blue sortion on two vegetable wastes: Cork bark and grape stalks," BioRes. 7(3), 3340-3354.
Two vegetable wastes, cork bark and grape stalks, were investigated for the removal of methylene blue from aqueous solution. The effects of contact time, dye concentration, pH, and temperature on sorption were studied relative to adsorption on a commercially-activated carbon. The highest adsorption yield was obtained within the pH range 5 to 10 for grape stalks and 7 to 10 for cork bark. The sorption kinetics of dye onto activated carbon and grape stalks was very fast. Kinetics data were fitted to the pseudo-first and second order kinetic equations, and the values of the pseudo-second-order initial rate constants were found to be 1.69 mg g-1 min-1 for activated carbon, 2.24 mg g-1 min-1 for grape stalks, and 0.90 mg g-1 min-1 for cork bark. Langmuir maximum sorption capacities for activated carbon, grape stalks, and cork bark for methylene blue estimated by the Orthogonal Distance Regression method (ODR) were 157.5 mg g-1, 105.6 mg g-1, and 30.52 mg g-1, respectively. FTIR spectra indicated that carboxylic groups and lignin play a significant role in the sorption of methylene blue. Electrostatic forces, n-p interactions, cation-p, and p-p stacking interactions contribute to methylene blue sorption onto grape stalks and cork bark. Grape stalks can be considered an efficient biosorbent and as a viable alternative to activated carbon and ion-exchange resins for the removal of methylene blue. PDF
Li, F., Yao, R., Wang, H., Hu, H., and Zhang, R. (2012). "Process optimization for sugars production from rice straw via pretreatment with sulfur trioxide micro-thermal explosion," BioRes. 7(3), 3355-3366.
The effects of sulfur trioxide micro-thermal explosion (STEX) and enzyme loading on reducing sugars conversion of STEX-treated rice straw and enzymatic hydrolysates were researched. Important process parameters in the pretreatment of biomass were identified by a Plackett-Burman design, and parameters with significant effects were optimized using a Box-Behnken design (BBD) and response surface methodology (RSM). The optimal conditions were a temperature of 80 °C and a treatment time of 30 min when only single factors were considered. Meanwhile, glucose and xylose were primary components in the enzymatic hydrolysates. Subsequently, STEX time, liquid-solid ratio, and soaking temperature were the main factors governing the enzymatic saccharification of rice straw. The optimum pretreatment conditions were STEX time 23.3 min, liquid-solid ratio 13.3 (V/m), and soaking temperature 62.2 °C. The chemical composition analysis of straw further demonstrated that STEX collaborative dilute lye pretreatment could remove lignin and hemicellulose. PDF
It is important to further improve the strength properties of alkaline peroxide mechanical pulp (APMP) in order to extend its applications in more paper grades. In this work, aspen APMP was pretreated by xylanase, and its effect on the improvement of paper strength properties was investigated. The results showed that, for xylanase-pretreated pulp, the tensile, tear and burst indexes were respectively about 14%, 23%, and 18% greater than those of untreated pulp. Meanwhile, the fines content and kink index decreased to some extent with the enzyme treatment. The total carboxyl content, crystallinity index, and water retention value of the pulp was increased significantly, and a higher porosity was observed on the fiber surface. Further investigation revealed that the lignin coverage of the fiber surface decreased from 59.2% to 55.2% after enzyme treatment, and the C1/C2 ratio decreased from 24.4 to 14.4. The improvement of strength properties can be ascribed to the increase in carboxyl groups and crystallinity, and a decrease in fines content and kink index, as well as to the removal of a portion of xylan and lignins from the fiber surfaces. PDF
Agger, J., and Meyer, A. S. (2012). "Alteration of biomass composition in response to changing substrate particle size and the consequences for enzymatic hydrolysis of corn bran," BioRes. 7(3), 3378-3397.
Corn bran is a by-product from corn starch processing. This work examined the effects of changing substrate particle size on enzymatic hydrolysis of both raw and pretreated destarched corn bran. The biomass composition of the corn bran varied between particle size fractions: The largest particles ([1000;710]µm) were richer in cellulose and in (arabino) xylan with a relatively low degree of arabinofuranosyl substitutions, whereas the smaller particles ([250;150]µm) contained less cellulose, but arabinoxylan with higher arabinofuranosyl substitution (higher A:X ratio). Enzymatic hydrolysis yields improved with decreasing substrate particle size, particularly for the raw corn bran. The increased enzymatic yields obtained with decreasing substrate particle sizes were related to the increased substrate surface area but also to the biomass composition. Theoretical estimations of enzymatic reaction efficiency supported that biomass composition affected the enzymatic reaction yields and provided new insight into the impact of substrate particle size on enzymatic biomass hydrolysis. PDF
Tomé, L. C., Fernandes, S. C. M., Sadocco, P., Causio, J., Silvestre, A. J. D., Pascoal Neto, C., and Freire, C. S. R. (2012). "Antibacterial thermoplastic starch-chitosan based materials prepared by melt-mixing," BioRes. 7(3), 3398-3409.
Antibacterial thermoplastic starch-chitosan based materials were successfully prepared by melt-mixing. The effect of chitosan modification (quaternization and grafting of long carbon chains) on the properties of the materials was also studied. All the ensuing materials were characterized in terms of thermal stability, crystalline structure, mechanical performance, and antibacterial activity. The incorporation of chitosan and its derivatives into the thermoplastic starch matrices resulted in an increment in tensile strengths (up to 85%); however for higher chitosan contents (5 and 7.5 wt.%), a decrease on the Young’s modulus (around 50%) was observed, together with an increment in the elongation at break, which can be attributed to the prevention of the retrogradation process. Finally, the thermoplastic starch materials incorporated with 7.5 wt% of the unmodified chitosan and of the water-soluble chitosan derivative had partial (about 20% reduction of CFU) and total bactericidal effect against S. aureus. PDF
Characterization of mass transfer properties was achieved in the longitudinal, radial, and tangential directions for four Australian hardwood species: spotted gum, blackbutt, jarrah, and messmate. Measurement of mass transfer properties for these species was necessary to complement current vacuum drying modeling research. Water-vapour diffusivity was determined in steady state using a specific vapometer. Permeability was determined using a specialized device developed to measure over a wide range of permeability values. Permeability values of some species and material directions were extremely low and undetectable by the mass flow meter device. Hence, a custom system based on volume evolution was conceived to determine very low, previously unpublished, wood permeability values. Mass diffusivity and permeability were lowest for spotted gum and highest for messmate. Except for messmate in the radial direction, the four species measured were less permeable in all directions than the lowest published figures, demonstrating the high impermeability of Australian hardwoods and partly accounting for their relatively slow drying rates. Permeability, water-vapour diffusivity, and associated anisotropic ratio data obtained for messmate were extreme or did not follow typical trends and is consequently the most difficult of the four woods to dry in terms of collapse and checking degradation. PDF
Pulp from the alkaline peroxide mechanical pulping (APMP) of oil palm empty fruit bunch, EFB, was fractionated with varying mesh-size screens to examine the effects imposed by size-specific fines on the produced pulp network. Occurring mainly as a result of refining, fines elements with dimensions almost resembling EFB fibres were the long tube-like tapered vessels from the arrays of adjoined cell walls detached along the perforation lines. These fibrillated vessel elements constituting the P250/R300 fines fraction improved pulp network strength by gluing onto multiple fibres. More profound strength enhancement was promoted by the segments of the fibrillated vessel elements constituted in the P300/R400 fines fraction. With reduced dimensions, these elements enhanced pulp network strength by filling the micro-voids in the pulp network. By eliminating gaps that would otherwise interrupt inter-fiber bonding, 12% P300/R400 fines fraction enhanced the EFB APMP pulp network tensile strength by 100%. PDF
Generation of virtual poles, based on the statistical distribution of selected visual and physical properties, and the estimation of their mechanical properties are of great help for predicting the quality of the roundwood that a forest stand can provide. With this objective in mind, an algorithm, SIMPOLE (SIMulator of POLEs), was developed. This algorithm allows the generation of pole’s geometry, as well as the mechanical properties of clear wood and the distribution of knots along its length. This generation is made through statistical distributions. The generated poles are simulated, either according to standard EN14251 or according to EN14229, for testing with simple supported beam conditions or with cantilever beam conditions, respectively. The algorithm outputs are: the bending strength, the modulus of elasticity, the location, and cause of failure. The algorithm was calibrated with a sample of 56 maritime pine utility poles and validated with another sample of 57 small diameter maritime pine poles. The results for the validation sample show: for bending strength, a mean error of 16.9%, and for modulus of elasticity, a mean error of 17.2%. Based on these results, the algorithm shows potential to estimate mechanical characteristics of small diameter poles from a forest. PDF
Bamboo is a potential lignocellulosic biomass for the production of bioethanol because of its high cellulose and hemicelluloses content. In this research, ethanol organosolv pretreatment with dilute sulfuric acid as the catalyst was studied in order to enhance enzymatic saccharification of moso bamboo. The addition of 2% (w/w bamboo) dilute sulfuric acid in 75% ethanol had a particularly strong effect on fractionation of bamboo. It yielded a solids fraction containing 83.4% cellulose in the treated substrate. The cellulose conversion to glucose yield reached 77.1 to 83.4% after enzymatic hydrolysis of the solids fraction for 48 h at an enzyme loading of 15 FPU cellulase/g cellulose and 30 IU β-glucosidase/g cellulose. The enzymatic hydrolysis rate was significantly accelerated as the ethanol organosolv pretreatment time increased, reaching the highest enzymatic glucose yield of 83.4% after 48 h at 50 °C. The concentrations of fermentation inhibitors such as HMF (5-hydroxy-2-methyl furfural) and furfural were 0.96 g/L and 4.38 g/L in the spent liquor after the ethanol organosolv pretreatment, which were slightly lower than the concentrations quantified during H2SO4-water treatment. Spent liquor was diluted with water, and more than 87.2% of lignin in raw bamboo was recovered as ethanol organosolv lignin through the filtration process. PDF
The differential expression of metabolites in wood-forming tissue in response to abiotic stresses might regulate or decide the cell wall contents and architecture via multiple pathways or networks. In order to determine whether such chemical modifications were associated with compression wood formation in a Pinus koraiensis sapling stem, polar metabolites were identified by a gas chromatography-mass spectrometer (GC-MS) and their major chemical components were measured. Varieties and abundances of metabolites were significantly affected by the number of days during which the saplings were bent into an inclined position. Polysaccharides like glucose, fructose, and glucopyranoside sharply decreased in treated stems, and simultaneously, some compounds related to biological resistance increased. This indicated that the monomer content showed changes in polymer synthesis. However, major metabolites clearly showed changes at an stage of stress application but were not obvious at later stages. Fourier Transform Infrared Spectroscopy (FTIR), cellulose crystallinity, and quantitative analysis of lignin showed similar variation patterns at different inclined times, but no consistent relationship. PDF
Chen, D., Zhang, A.-P., Liu, C.-F., and Sun, R.-C. (2012). "Modification of sugarcane bagasse with acetic anhydride and butyric anhydride in ionic liquid 1-butyl-3-methylimidazolium chloride," BioRes. 7(3), 3476-3487.
Bagasse acetate butyrates were prepared homogeneously in 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) ionic liquid from ball-milled sugarcane bagasse by acylation with acetic anhydride and butyric anhydride. The parameters, including reaction temperature, reaction time, feeding method of adding anhydrides, the dosage of total anhydrides to SCB, and the molar ratio of acetic anhydride to butyric anhydride, were considered, and the extent of acylation was measured by weight percent gain (WPG). The results showed the positive effects of reaction duration and total anhydride dosage on WPG and the negative effects of reaction temperature and molar ratio of AA/BA on WPG. The feeding method of acetylation after butyrylation resulted in the increased WPG compared with acetylation before butyrylation. FT-IR and 1H–13C correlation 2D NMR (HSQC) studies provided evidence for acylation. The bagasse acetate butyrates showed increased thermal stability after acylation. This study provides a new way for high value-added utilization of renewable lignocellulosic biomass. PDF
To extend the application of mountain pine beetle (MPB) killed lumber for decking, siding, and landscaping materials, it is essential to improve its dimensional stability. Thermal treatment is one of the well-established processes used to improve wood stability by modifying chemical compounds and masking blue-stains by darkening the fibre color. In this study, the MPB lumber was subjected to thermal treatment at three temperatures (195, 205, or 215°C) and three exposure times (1.5, 2, or 3 h). Based on Duncan's multiple range test, the results indicated that the volumetric swelling after thermal treatment, either from oven-dry to air-conditioned or from oven-dry to water-saturated, was significantly reduced after thermal treatment. Modulus of elasticity was increased when specimens were treated at a temperature of 195°C, and then decreased as the temperature increased. Modulus of rupture was significantly reduced as treatment temperature increased. The hardness of lumber thermal-treated at 195°C was significantly increased compared to that of the untreated lumber. At higher temperatures, hardness started to decrease slightly. With the treatment temperature increasing to 215°C for 3 h, the color difference between stained and clear wood was reduced by 75%. As a result, the blue-stains vanished gradually. PDF
The main objective of this study was to evaluate three methodological approaches for the drying (air drying, solar drying, and hot-air drying) of three lignocelluloses residues in Costa Rica, namely the empty fruit bunches of oil palm (EFB), pineapple plant leaves (PL) with different treatments on this leaf, and sawdust from Gmelina arborea (GAD). The initial moisture content (MCi), the drying times, and the variation of moisture content (MC) with time were determined. A mathematical model of the relation between MC and drying time was also established. The results showed that the MCi was the highest in PL (over 79%), followed by EFB (over 47%), and GAD (lower than 47%). Drying times were higher for air drying, followed by solar drying, and finally hot-air drying. PL showed the longest drying times, followed by GAD and EFB. However, it can be reduced by shortening strands, application of grooves in the cuticle, or crushing the leaf. The MC variation model revealed that the function was Y = ax3 + bx2 + cx + d for all three drying techniques, and the weather conditions where the drying was tested. This model presents high coefficients of determination (over 0.97) and low percentage of errors (1.85-4.73%). PDF
Environmentally beneficial composites can be made by replacing synthetic fibers with various types of cellulosic fibers. Fibers from pine wood, coir, sisal, abaca, coir, etc. are all good candidates. The most important factor in finding good fiber reinforcement in the composites is the strength of adhesion between matrix polymer and fiber. Due to the presence of hydroxyl groups and other polar groups in various constituents of abaca, the moisture absorption is high, which leads to poor wettability and weak interfacial bonding between fibers and the more hydrophobic matrices. Therefore, it is necessary to impart a hydrophobic nature to the fibers by suitable chemical treatments in order to develop composites with better mechanical properties. In the present work, the effect of alkali treatment on the moisture absorption tendency of single abaca fiber was investigated. The results shown that the alkali treated fiber absorbs less moisture than the untreated raw fiber. PDF
Baharuddin, A. S., Md Yunos, N. S. H., Nik Mahmud, N. A., Zakaria, R., Md Yunos, K. F. (2012). "Effect of high-pressure steam treatment on enzymatic saccharification of oil palm empty fruit bunches," BioRes. 7(3), 3525-3538.
The effectiveness of high-pressure steam treatment (HPST) with various treatment temperatures (170, 190, 210, and 230 °C) on the enzymatic hydrolysis yield of oil palm empty fruit bunches (OPEFB) was successfully investigated. Analysis of the compositions of raw and treated OPEFB showed that significant changes occurred after the HPST was performed. Scanning electron microscopy (SEM) analysis showed that the treated OPEFB gave better results in removing the silica bodies as compared to the untreated OPEFB. This analysis was in agreement with FTIR results, which revealed a significant decrease in the content of hemicelluloses after HPST. During saccharification, the amount of sugar produced was higher for treated OPEFB than untreated OPEFB. Thus, the results suggest that HPST can be applied as an alternative treatment method for the alteration of OPEFB structure and to enhance the digestibility of the biomass, therefore improving enzymatic hydrolysis. PDF
This study deals with a biorefinery concept based on larch wood. Wood chips of Siberian larch (Larix sibirica Lebed.) were treated with water before pulping at the optimal pre-extraction (PE) condition of 150 °C and 90 minutes. Through PE, about 12.4% of the wood mass is dissolved, mainly from the arabinogalactan hemicellulose component. Fermentation of the hemicellulose-rich larch extract with Bacillus coagulans resulted in consumption of all C6 and C5 sugars and produced lactic acid in high yield. PE before pulping resulted in lower (4 to 5%) pulp yield than for control kraft pulps. However, the pulp yield loss may be reduced by addition of polysulfide (PS) and anthraquinone (AQ). The present study focuses on the effect of the degree of washing of the extracted chips and that of the PS charge in PSAQ pulping on the final properties of the pulp. Three different levels of washing and three different PS charges were tested. The characteristics of the extract, wash water, pulp, and black liquor samples were determined. The amount of sugars in the combined stream of collected extract and wash water obtained by mild washing was 10.2% on o.d. wood. PDF
Sesame leaf, an agricultural solid waste, was used as low cost adsorbent for removal of Pb(II) from aqueous solution in batch mode. The biosorbent was characterized by thermo-gravimetric analysis and Fourier transform infrared spectroscopy. The influences of phase contact time, solution pH, adsorbent dosage, and initial concentrations were investigated to optimize the conditions for maximum adsorption. The experimental data were analyzed by Langmuir, Freundlich, and Koble-Corrigan isotherm models. The Koble-Corrigan and Langmuir isotherms best represented the measured biosorption data. According to an evaluation using the Langmuir equation, the adsorption capacity of the biosorbent was found to be 279.86 mg g-1, which was higher or comparable to the adsorption capacity of various adsorbents reported in the literature. The kinetics of adsorption of Pb(II) was evaluated by pseudo-first order, pseudo-second order, and intra-particle diffusion kinetic models. The experimental data fitted very well with the pseudo-second order kinetic model. The intra-particle diffusion model is not a dominant rate controlling mechanism in the sorption of Pb(II). Thermodynamic analysis showed that the adsorption was a spontaneous and endothermic process. The results indicated that sesame leaf can be used as an effective biosorbent for Pb(II) removal from aqueous solutions. PDF
A rosin sizing agent designed to impregnate wood and immobilize copper in wood cells for protection against decay was investigated. Poplar (Populus ussuriensis) wood was impregnated with combinations of 3% CuSO4 solution and 1%, 2%, or 4% rosing sizing agent. The decay resistance of treated wood blocks was measured by a soil-block culture method. After a 12-week decay test, the weight losses of untreated control blocks were 70.45% by Trametes versicolor and 61.84% by Gloeophyllum trabeum. The wood decay resistance was also slightly improved by the treatment with only the rosin sizing agent. However, after being treated with the rosin sizing agent and CuSO4, the wood had great decay resistance. The average weight losses of the samples degraded by fungi were less than 4%. Notably, the leached wood blocks had a weight loss of less than 3%. After leaching, the copper content in the leachates was analyzed by atomic absorption spectroscopy (AAS). Results showed that the amount of copper ions released from the samples treated with the copper-rosin solutions was half those from the samples treated with copper alone. Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM-EDX) proved that the copper element was still in the cell lumens of leached wood blocks, which is consistent with the results of AAS analysis. This signifies that the rosin sizing agent is very helpful to fix the copper preservative in wood. PDF
The vibrational properties of Chinese fir (Cunninghamia lanceolata) wood were investigated in this study as a function of changes in moisture content (MC) and grain direction. The dynamic modulus of elasticity (DMOE) and logarithmic decrement (δ) were examined using a cantilever beam vibration testing apparatus. It was observed that DMOE and δ of wood varied widely during moisture adsorption and desorption. The DMOE of wood conditioned by the adsorption process showed significant increases during the later stages of conditioning when the MC scarcely changed. However, with the desorption process, the DMOE did not increase as much during the later stages of conditioning, though they increased during the early stages of conditioning when the MC greatly decreased. These results suggest that wood in an unstable state, caused via the existing state of moisture, shows different vibrational behaviors. Furthermore, the parallel to grain direction showed much higher DMOE and lower δ when compared to the perpendicular to grain direction. The variation of vibrational properties between parallel and perpendicular to grain direction under constant MC and during moisture adsorption process could be attributed due to the microscopic, macroscopic molecular, as well as chemical constituents of wood. PDF
The effect of temperature in the range from 25 ºC to 175 ºC on the bending performance of plywood and medium density fiberboard (MDF) has been studied with the ultimate purpose of optimizing the post-processing using radio frequency heating and improving the quality of the final products. Static 3-point bending tests were conducted on a universal testing machine inside a computer-controlled chamber. Results show that the bending strength (MOR) and modulus of elasticity (MOE) of plywood and MDF decrease with the increase of the temperature from 25 ºC to 175 ºC. The bending strength of plywood and MDF decreases with the increase of the exposure time. However, the effects of exposure time on MOE of plywood and MDF are not obvious. Plywood and 2.6 mm thick MDF show a typical elasto-plastic behavior, while 12 mm thick MDF does not exhibit any plastic behavior. It is recommended that the post-processing procedure should be completed within 15 minutes for both MDF and plywood. PDF
Much of the hemicellulose fraction of pulp mill feedstock is released into black liquor during the pulping process, and it is combusted to recover chemicals and energy in the form of steam and electricity. It is technically feasible to recover this fraction of carbohydrates and convert it into value-added products. In this study, a portion of the hemicellulose in pulp feed was hydrolyzed to soluble sugars by hot-water treatment. The sugars (mixtures of pentose, hexose, and their oligomers) were then converted to ethanol by simultaneous saccharification and fermentation (SSF) employing pectinase and the ethanologenic microorganism, Saccharomyces cerevisiae. The prehydrolysate produced from wood also contained toxins, primarily lignin and sugar degradation products, which strongly inhibited the microbial and the enzymatic reactions. De-toxification of the prehydrolysates was achieved by over-liming (addition of excess CaO). The total sugar concentration in the prehydrolysate obtained from softwood was below 4 wt%, which is roughly equivalent to 2 wt% ethanol, far below the acceptable level for downstream processing. In our previous study (Kang et al. 2010), a certain amount of water is added to attain fluidity required for SSF operation. In this study, prehydrolysate, in place of water, was added into the bioreactor along with the sludge. The proposed scheme has proven that total sugar concentration as well as product concentration in the bioreactor can be significantly increased above that of the sludge-alone operation. PDF
Abu Bakar, N. K., Zanirun, Z., Abd-Aziz, S., Ghazali, F. M., and Hassan, M. A. (2012). "Production of fermentable sugars from oil palm empty fruit bunch using crude cellulase cocktails with Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2 for bioethanol production," BioRes. 7(3), 3627-3639.
Utilization of oil palm empty fruit bunch (OPEFB) for bioethanol production with crude cellulase cocktails from locally isolated fungi was studied. Enzymatic saccharification of alkaline pretreated OPEFB was done using different cellulase enzyme preparations. Crude cellulase cocktails from Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2 produced 8.37 g/L reducing sugars with 0.17 g/g yield. Production of bioethanol from OPEFB hydrolysate using Baker’s yeast produced approximately 0.59 g/L ethanol, corresponding to 13.8% of the theoretical yield. High reducing sugars concentration in the final fermentation samples resulted from accumulation of non-fermentable sugars such as xylose and cellobiose that were not consumed by the yeast. The results obtained support the possible utilization of OPEFB biomass for bioethanol production in the future. PDF
Birch xylan (4-O-methylglucuronoxylan) isolated from a kraft cooking liquor was delignified and grafted with polylactide of predictable branch length. This graft copolymerization resulted in very high total yields, greater than 90%, and with less than 10% polylactide homopolymer byproducts. Mild reaction conditions (40°C, 5 to 120 minutes) were used, which was believed to limit transesterification reactions and thus make it possible to reach good predictability of the polylactide branch length. The thermal properties of the polylactide-grafted xylan depended on the branch length. Short branches resulted in fully amorphous materials with a glass transition temperature of about 48 to 55°C, whereas long polylactide branches resulted in semi-crystalline materials with melting points of about 130°C. Using mixtures of L-lactide and D/L-lactide in the monomer feed further altered the thermal properties. The degradation temperatures of the polylactide-grafted xylans were higher than that of the unmodified xylan, with degradation temperatures of about 300°C and 250°C, respectively. Tensile testing showed increased elongation at break with increasing branch length. The proposed method thus enables tailor-making of copolymers with specific thermal and mechanical properties. PDF
Allegretti, O., Brunetti, M., Cuccui, I., Ferrari, S., Nocetti, M., and Terziev, N. (2012). "Thermo-vacuum modification of spruce (Picea abies Karst.) and fir (Abies alba Mill.) wood," BioRes. 7(3), 3656-3669.
The study presents results of the characterization of Norway spruce (Picea abies Karst.) and fir (Abies alba Mill.) wood thermally modified by TERMOVUOTO® technology at temperatures in the range of 160 to 220°C in vacuum conditions. Sixteen thermo-vacuum treatment tests were carried out using a pilot laboratory unit on 30-mm-thick spruce and fir boards in various combinations of the process parameters, i.e. temperature (T), duration (t), and pressure (p). The treated material was characterized to reveal the changes of the physical-mechanical properties including color and durability. The treated wood showed an improved performance with relation to the dimensional stability and durability. The measured mechanical properties did not show any significant decrease. Analytical models, based on the existing correlations between wood properties and process parameters, were assessed, thus allowing the control of the process. PDF
In this study, the effect of drying temperature, from 50 °C to 90 °C, on the drying characteristics of powdered peanut shell was investigated, and an isothermal procedure was used to determine the moisture diffusivity and the activation energy. All the experiments were performed using a thermogravimetric analyzer (TGA) for rapidly achieving the isothermal condition and accurately recording the mass loss of the sample. With increasing drying temperature, the drying rate increased and the drying time decreased. A short rising rate period was found in all drying processes due to increasing temperature of the sample in the beginning of drying. The predicted values by the diffusion model based on Fick's second law were in good agreement with the experimental data obtained from the falling rate period. The values of effective moisture diffusivity ranged from 9.60 x 10-9 to 2.26 x 10-8 m2/s, and the activation energy was determined to be 21.2 kJ/mol. PDF
With thermal modification, changes in properties of wood, such as the presence of VOC and water-soluble carbohydrates, may occur. Thermal modifications under saturated steam conditions (160 °C or 170 °C) and superheated steam conditions (170, 185, and 212 °C) were investigated by analysing the presence of water-soluble 5-(hydroxymethyl)furfural (HMF), furfural, and carbohydrates in heat-treated wood. The influence of thermal modifications on Scots pine, Norway spruce, and silver birch was also studied. Furfurals were analysed using HPLC at 280 nm, while monosaccharides and water-soluble carbohydrates were determined by GC-FID as their acetylated alditiols and, after methanolysis, as their trimethylsilylated methyl-glycosides, respectively. The amount of furfurals was larger in boards thermally modified under saturated steam conditions than those treated under superheated steam conditions. Generally, more of HMF than furfural was found in the thermally modified boards. In process water, in which saturated steam conditions had been used, furfural and only traces of HMF were found. Higher content of water-soluble carbohydrates was found in boards treated in saturated steam rather than in superheated steam. After modification in saturated steam, substantial parts of the water-soluble carbohydrates were due to monosaccharides, but only traces of monosaccharides were found in boards treated under superheated steam conditions. PDF
Rodionova, G., Roudot, S., Eriksen, Ø., Männle, F., and Gregersen, Ø. (2012). "The formation and characterization of sustainable layered films incorporating microfibrillated cellulose (MFC)," BioRes. 7(3), 3690-3700.
Microfibrillated cellulose (MFC), TEMPO-pretreated MFC, and hybrid polymer/MFC mix were used for the production of layered films with interesting properties for application in food packaging. The series of samples were prepared from MFC (base layers) using a dispersion-casting method. The same procedure as well as a bar coating technique was applied to form top layers of different basis weights. The barrier properties and formation of the layered films were investigated in relationship to the preparation procedures, combination of layers, and areal weight (basis weight). Characterization was done with respect to oxygen transmission rates (OTR), water vapor transmission rates (WVTR), tensile properties, and contact angles (CA) with water. The produced layered films yielded OTR values of 4 mL m-2 day-1 and fulfilled oxygen barrier requirements for a modified atmosphere packaging (MAP). Hornification of the MFC films, however, occurred during drying, which may result in a loss of the film’s beneficial properties. PDF
A repulping approach of waste Chinese banknote paper, i.e., Renminbi (RMB) paper with high wet strength, was studied, and a dual-pH pretreatment process was used before refining. Pretreatment temperature, soaking time, and consistency of waste RMB paper were investigated to obtain the optimum repulping parameters. The results showed that when the pretreatment temperature was 80 °C, soaking time was 60 min, and consistency was 10%, the repulping yield was 88.1%. The arithmetic and weighted mean lengths of fine pulp fibers from the optimum experiment were 0.564 mm and 0.785 mm, respectively, and the mean width was 22.5 μm. Obvious kinks and broken ends, as well as a slight curl of fine pulp fibers were observed by analyses with a Morfi-compact fiber analyzer and a scanning electron microscope. The results from Fourier transform infrared spectroscopy analysis possibly demonstrated that the ester bonds in waste banknote paper were destroyed after the dual-pH pretreatment. PDF
Experimental parallel strand lumbers (PSLs) were manufactured from fast growing rotary peeled I-214 (Populus x euramericana) and I-77/51(Populus deltoides) hybrid poplar clones veneer strands with melamine urea formaldehyde (MUF) adhesive. The results showed that hybrid poplar clones can be used in PSLs manufacturing. Physical and mechanical properties of PSLs were affected by clone types. The I-77/51 clone had better properties and was found to be more suitable for PSLs manufacturing compared to the I-214 clone. PSLs properties were higher than those of solid woods (SWs) and laminated veneer lumbers (LVLs) of the same poplar clones. This increase may be due to materials, densification as a result of high pressure use, and the manufacturing techniques. The degree of contribution of SWs properties to the PSLs properties was lower than that of LVLs. This indicated that factors other than SWs properties played more important roles in the strength increase of PSLs. PDF
During torrefaction of biomass, equivalence between temperature and residence time is often reported, either in terms of the loss of mass or the alternation of properties. The present work proposes a rigorous investigation of this equivalence. Cellulose, as the main lignocellulosic biomass component, was treated under mild pyrolysis for 48 hours. Several couples of T-D (temperature-duration) points were selected from TGA curves to obtain mass losses of 11.6%, 25%, 50%, 74.4%, and 86.7%. The corresponding residues were subjected to Fourier transform infrared spectroscopy for analysis. According to the FTIR results, a suitably accurate match to global T-D equivalence is exhibited up to 50% mass loss: in this domain, mass loss is well correlated to the treatment intensity (molecular composition of the residue) except for slight differences in the production of C=C and C=O. For mass loss levels of 74.4% and 86.7%, distinct degradation mechanisms take place at different combinations of temperature and duration, and the correlation fails. Compared to the mass loss at 220°C and 250°C, the equivalent molecular composition can be achieved through treatment at 280°C with shorter treatment time and less depolymerization and oxidation. The main conclusion drawn is that mass loss can be used as a synthetic indicator of the treatment intensity in the temperature range of 220°C to 280°C up to a mass loss of 50%. PDF
Chowdhury, Z. Z., Zain, S. M., Khan, R. A., Arami-Niya, A., and Khalid, K. (2012). "Process variables optimization for preparation and characterization of novel adsorbent from lignocellulosic waste," BioRes. 7(3), 3732-3754.
In this study, powdered activated carbon (PAC) was produced from agricultural waste biomass of kenaf (Hibiscus cannabinus L.) core or stalk, and the process variables were optimized by applying central composite design (CCD). The influences of carbonization temperature, duration of activation, and impregnation ratio on removal percentage of copper Cu(II) ions from aqueous solution and carbon yield were investigated. A quadratic model for adsorption percentage and a 2FI model for carbon yield were developed. The models were used to determine optimum process variables for production of activated carbon from the woody core of kenaf. From the analysis of variance (ANOVA), the most significant factor on each response of adsorption capacity and yield were identified. An activation temperature of (568±1)°C, activation time of 2.02 hours, and impregnation ratio of 1.75 were found as optimum production conditions. The experimental results showed excellent agreement with the predicted results obtained from a designed experiment that included the variables and responses of sorption capacity and yield. Textural properties of the prepared activated carbons were determined. The performance of the prepared activated carbon was further evaluated by fitting the equilibrium data with regression equations of Langmuir, Freundlich, and Temkin models at different temperatures. The research concluded that the prepared sorbent has good potential to remove Cu (II) ions from waste water. PDF
Feng, Y., Qi, X., Jian, H.-L., Sun, R.-C., and Jiang, J.-X. (2012). "Effect of inhibitors on enzymatic hydrolysis and simultaneous saccharification fermentation for lactic acid production from steam explosion pretreated Lespedeza stalks," BioRes. 7(3), 3755-3766.
The effects on both cellulose conversion rate and lactic acid yield were studied by adding inhibitors, including formic acid, acetic acid, furfural, and vanillin into the hydrolysate of steam-pretreated Lespedeza stalks. The results suggest that formic acid has a significant influence on the enzyme activity and poisoned bacterial cells, resulting in the reduction of cellulose conversion rate and lactic acid yield by 21% and 16.4%, respectively. Acetic acid showed a strong inhibition on simultaneous saccharification fermentation (SSF) process, but little effect on enzymatic hydrolysis. Hydrolysis and SSF were less affected by furfural and vanillin compared with weak acids. The lactic acid yield of Lespedeza stalks rinsed with water increased from 64.0% to 89.4%, and the time to reach the maximum concentration was shortened from 96 hours to 48 hours when compared with the unwashed materials. PDF
This paper studies the influence of ammonia gas on wood color changes in response to an increasing demand for dark colored wood specimens. The darker wood color in ammonia fuming is accomplished through chemical reactions between ammonia gas and wood compounds. We exposed oak, maple, spruce, and larch wood samples to ammonia gas for 16 days. During fuming, the color changes were studied using CIE L*a*b* parameters. After fuming, the changes in extractives content, tannin, and nitrogen content were analyzed. The chemical changes of wood and residues of wood extractives after fuming were analyzed by FTIR spectroscopy. Oak wood reacted intensively with ammonia gas in a very short time, and the darkening was prominent for all the investigated wood species. It was established that tannin had no major influence on color changes of maple and larch wood in the ammonia-fuming process. The FTIR spectra of fumed wood indicated involvement of carbonyl groups, and the FTIR spectra of wood extractives indicated involvement of carbonyl, aromatic, and alcohol groups in reaction with ammonia gas. PDF
The anatomical properties of seven hybrid poplar clones grown in three sites in southern Quebec, Canada were investigated. Radial and longitudinal variations in selected anatomical properties of wood were measured by image analysis of transverse sections and by fiber quality analysis. Results indicate that all measured anatomical properties varied significantly across sites. Clonal variation was highly significant for all anatomical properties studied, and broad-sense heritability ranged from 0.10 (average vessel lumen area) to 0.76 (cell wall area percentage). Genetic gain was positive for all anatomical properties. The variation in radial pattern was characterized by a rapid increase in the first few years in fiber length, width, and proportion, wall thickness, and percent cell wall area. Ray proportion remained constant, whereas the vessel lumen area and proportion decreased with cambial age. PDF
Chemical modifications of hemp fibers were performed with acetic anhydride (AA) and vinyl acetate (VA) in the presence of pyridine or potassium carbonate as catalysts. Hemp fibers (Cannabis sativa) were successfully acetylated by VA in the presence of potassium carbonate (15% WPG), but no weight gain was obtained when pyridine was used as catalyst. Hemp fibers were also modified with acetic anhydride (AA) in the presence of potassium carbonate and pyridine as catalyst (14% and 16% WPG, respectively) under identical conditions, and the results were compared with those obtained using the VA technique. AA-modified, VA-modified, and control hemp fibers were characterized by Infrared (FTIR), 13C CP MAS NMR and thermo gravimetric analysis (TGA). PDF
A batch study of boron removal from aqueous solutions by adsorption using rice husk was carried out. The effect of selected parameters such as particle size, pH, adsorbent dosage, and initial concentration of adsorbate on boron removal was investigated in the study. Results showed that the maximum boron removal was obtained with the rice husk particle size between 0.425 mm and 1.0 mm at pH 5. Boron removal was increased with an increasing amount of adsorbent dosage but decreased as the initial concentration of adsorbate increased. A Freundlich isotherm was used to describe the potential of boron adsorption using rice husk. The maximum adsorption capacity of rice husk was found to be 4.23 mg/g for boron removal. PDF
Eucalyptus wood is among the most important biomass resource in the world. Wood mechanical defibration and fibrillation are energy-intensive processes utilized not only to produce pulp for papermaking, but also to produce reinforcement fibers for biocomposites, nanocellulose, or pretreat lignocellulosic material for biofuels production. The structural features of different Eucalyptus hybrids affecting the refining energy consumption and produced fiber furnish properties were evaluated. The defibration and fiber development were performed using an alkaline peroxide mechanical pulping (APMP) process, which included chelation followed by an alkaline peroxide treatment prior to wood chip defibration. Despite the similar wood densities and chemical compositions of different Eucalyptus hybrids, there was a clear difference in the extent of defibration and fibrillation among the hybrids. The high energy consumption was related to a high amount of guaiacyl lignin. This observation is of major importance when considering the optimal wood hybrids for mechanical wood defibration and for understanding the fundamental phenomena taking place in chemi-mechanical defibration of wood. PDF
Haji Mirza Tayeb, S. A., Jahan Latibari, A., Tajdini, A., and Sepidehdam, S. M. J. (2012). "The influence of pulp refining on de-inking potential and strength properties of ink jet printed paper," BioRes. 7(3), 3837-3846.
The effect of laboratory refining on de-inking potential of inkjet printed handsheets was investigated. Pulp samples containing 80% short fiber and 20% long fiber were beaten in a PFI mill to reach four predetermined freeness levels of 650 (unrefined), 550, 430, and 340 mL CSF, and then handsheets were made. Handsheets were identically inkjet printed and then de-inked. Results revealed that, at lower freeness value, the brightness of de-inked pulps was higher, but the opacity decreased. The surface roughness of handsheets produced using different refined pulp before de-inking was reduced. Our results showed that refining will impart a positive effect on handsheets’ de-inking potential, and de-inking printed papers produced from pulps refined to lower freeness generated the highest brightness. The results revealed that both tensile and tear strength indices of de-inked pulp were lower. However, the tear strength index of unrefined sample and the tensile strength index of pulp refined to 430 ml CSF were higher than for undeinked samples. PDF
Henan is the main agricultural province in China and is the top producer of wheat, representing 25% of the national wheat output. Henan has been the top province in terms of total food crop production since 2000. So, agricultural residue resources, which could provide material for future social and economic development, are abundant in Henan. But the province is facing critical problems from burning agricultural residues. Both efficient use and environmental protection of the resources are beginning to receive more attention. This study assessed the agricultural residue resources available for utilization and examined recent development targets in Henan. Agricultural residues were estimated for the base year 2009. Approximately 59.12 million tonnes of agricultural residues were consumed in various ways, and the average percentage of agricultural residue utilization was 70.07%. Agricultural residue is mainly used as a fertilizer, an energy source, industrial material, forage, and as feedstock for edible fungi. Short-term targets were provided for the development of suitable uses for agricultural residues through several demonstration projects, which will help to increase the efficient use of agricultural residue in Henan, China. PDF
The effect of compressive pretreatment before chemical pulping on the properties of poplar kraft and soda-AQ pulp was evaluated. Compressive pretreatment not only resulted in the dissolution of hemicellulose, but also leached extractives. Pulps made from compressive pretreated wood chips required lower beating energy than the untreated pulps to achieve the same beating degree of 45°SR, and the brightness of the handsheets was improved by 2% ISO. Compressive pretreatment allowed for efficient delignification and saved about 6% alkali consumption to achieve similar pulp screen yield. Furthermore, a higher content of fines and slightly lower mechanical properties were observed after the compressive treatment. PDF
Waxy maize contains nearly 100% of the branched amylopectin type of starch, which has a similar structure to that of a commercial anionic organic micro-particle (OMP). It was found that the maize starch would have the same function as the OMP if carboxymethyl groups were introduced; moreover, the performance of carboxymethyl starch as a retention and drainage aid could be enhanced by grafting some cationic groups on the backbone of the starch so that it could absorb on fibers through electrostatic attraction. In this study, the introduced groups of cationic-modified carboxymethyl starch (CCMS) prepared from waxy maize were determined by FT-IR and 1H NMR spectroscopy. Factors affecting retention and drainage, comparison between CCMS and OMP systems, and also the strengthening effect of CCMS were studied. The results showed that CCMS had excellent performance when it was used with cationic polyacrylamide (CPAM) as a retention system. Compared with the OMP, CCMS had better retention performance when the dosage was in the range from 0.01% to 0.08%, and it yielded much more uniform formation of the handsheets. Additionally, CCMS had a strengthening effect on the paper, which distinguished it from other retention aids. PDF
Ardanuy, M., Claramunt, J., Arévalo, R., Parés, F., Aracri, E., and Vidal, T. (2012). "Nanofibrillated cellulose (NFC) as a potential reinforcement for high performance cement mortar composites," BioRes. 7(3), 3883-3894.
In this work, nanofibrillated cellulose (NFC) has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties (cellulose content and microfibrillar angle), sisal, and cotton linters pulps, were initially characterised in order to assess their reinforcing capability. Sisal pulp was found to be most suitable as reinforcement for the brittle cementitious matrix. Nanofibrillated cellulose was produced by the application of a high intensity refining process of the sisal pulp. It was found that 6 hours of refining time was required to obtain the desired nanofibrillation of the fibers. Cement mortar composites reinforced with both the sisal fibres and the nanofibrillated cellulose were prepared, and the mechanical properties were determined under flexural tests. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited enhanced flexural properties, but lower values of fracture energy, than the ones reinforced with the conventional sisal fibres. PDF
Internal addition of fluorochemical greaseproof agent was applied to furnishes of different fibers, filler, binder types, and loadings to examine their effects under different degrees of refining on the greaseproof indicators such as air resistance, water absorption, and the Kit values of the resulting handsheets. The results showed that more refining tended to produce a tighter textured paper which was more suitable for the greaseproof purpose. The Kit values of the resulting handsheets were found to correlate with a polynomial regression equation of the Gurley air resistance (A) of the paper with an equation of Kit no. = 2.51 + 0.064 A – 0.002 A2. The results also showed that furnishes that blended northern softwood and Eucalyptus pulps at ratios from 25:75 to 75:25, depending on the strength requirements, had the best greaseproof performance. Among the fillers, sericite was superior to bentonite and PCC for contributing to greaseproof properties. However, filler loading exceeding 6.1% was undesirable. Soluble starch and polyvinyl alcohol were suitable binders for making greaseproof papers. Their dosages should be kept between 0.4 to 1.6%. PDF
Silva, T. C. F., Gomide, J. L., and Santos, R. B. (2012). "Evaluation of chemical composition and lignin structural features of Simarouba versicolor wood on its pulping performance," BioRes. 7(3), 3910-3920.
Simarouba versicolor wood was evaluated relative to its kraft pulping ability and compared with Eucalyptus urograndis wood. Comprehensive chemical analysis of wood and milled wood lignin (MWL) was performed, aiming to correlate wood and lignin structural features with kraft pulping response. Wood characterization of S. versicolor revealed higher lignin content (37.3%) and lower cellulose content (45.1%) than E. urograndis. 13C NMR spectroscopy was performed to characterize MWL, and the results showed a lower syringyl to guaiacyl ratio (S/G), higher degree of condensation, and lower β-O-4 linkages for S. versicolor. The gross heating value of S. versicolor was slightly higher than that for E. urograndis. Significant variations were observed in chemical charge demand and in pulping yield for the two species. This behavior was attributed mainly to the S/G ratio and degree of condensation of the lignin, although total and insoluble lignin, as well as cellulose contents may have affected pulping efficiency too. PDF
Teghammar, A., Chandra, R., Saddler, J. N., Taherzadeh, M. J., and Sárvári Horváth, I. (2012). "Substrate characteristic analysis for anaerobic digestion: A study on rice and triticale straw," BioRes. 7(3), 3921-3934.
Different substrate characteristic analyses have been studied on rice and triticale straw pretreated with NMMO (N-methylmorpholine-N-oxide) prior to biogas production. Simons’ stain, water retention value (WRV), and enzymatic adsorption were used to measure the change in the accessible surface area of the lignocellulosic substrates. FTIR was used to measure the change in cellulosic crystallinity and Time-of-Flight-Secondary-Ion-Spectroscopy (ToF-SIMS) to measure the ratio of cellulose to lignin on the sample surface. All methods showed increased accessible surface area and a decrease in crystallinity after the pretreatments. These qualities were linked to improved biogas production. In the future, the tested methods could replace the time-consuming methane potential analysis to predict the methane production of lignocellulosic materials. Simons’ stain, enzymatic adsorption, and crystallinity measurement by FTIR can be regarded as the recommended methods for the prediction of the improved biogas production as a result of the pretreatment. PDF
Krongtaew-Sakdaronnarong, C., Onsrithong, N., Suwankrua, R., and Jonglertjunya, W. (2012). "Improving enzymatic saccharification of sugarcane bagasse by biological/physico-chemical pretreatment using Trametes versicolor and Bacillus sp.," BioRes. 7(3), 3935-3947.
In this work, laccase biosynthesis of two microorganisms, Trametes versicolor TISTR 3224 and Bacillus sp. TISTR 908 isolated in Thailand, was investigated using sugarcane bagasse (SCB) as substrate. Two-stage biological/physico-chemical pretreatment of SCB on delignification and saccharification yield was studied. A two-level full factorial design was applied and 3 factors influencing delignification and saccharification processes of SCB were studied including C:N ratio (10:1 to 20:1), temperature (100 to 140°C), and alkali concentration (0 to 5% w/w NaOH). It was found that during biological pretreatment of SCB, a greater amount of laccase was produced from T. versicolor in the early stage of growth compared with Bacillus sp. Nitrogen supplement enhanced laccase biosynthesis of T. versicolor. By contrast, Bacillus sp. required a smaller amount of nitrogen source to produce laccase. Biological treated bagasse was subsequently subjected to a physico-chemical treatment. The results showed that the highest xylose and glucose yield of 51.97% w/w based on carbohydrate content was obtained from T. versicolor cultivation at a C:N ratio of 20:1, and consecutively treated in 5% w/w NaOH solution at 140°C for 1 h. Bacterial/alkali and alkali pretreatment yielded xylose and glucose in smaller degrees compared with fungal/alkali pretreatment. T. versicolor preferentially degraded lignin in sugarcane bagasse relative to cellulose and hemicelluloses constituents, while Bacillus sp. simultaneously attacked both lignin and carbohydrate moieties, as indicated by analysis of relative FT-IR intensities ratios of pretreated and untreated sugarcane bagasse. PDF
High-yield pulp (HYP) such as bleached chemi-thermo-mechanical pulp (BCTMP) from aspen wood, is now being used in the production of high-quality fine papers, and this is particularly true in China. In this study, the effect of using cationic polymers such as poly-aluminum chloride (PAC), polyethylenimine (PEI), cationic polyacrylamide (CPAM), and poly-(diallyldimethylammonium chloride) (PDADMAC) on Alkenyl Succinic Anhydride (ASA) sizing efficiency in HYP-containing pulp furnish was investigated. The results showed that the addition of only ASA emulsion to the HYP-containing furnish, without any cationic additives, did not yield an appreciable degree of sizing in the paper sheet. PAC (or alum) could improve the ASA sizing efficiency. PEI, PDADMAC, CPAM, and NaHCO3 all improved ASA sizing efficiency in the presence of PAC. The charge density of PEI was important for improving the ASA sizing performance. Also, the sequence of adding the cationic polymer affected the ASA sizing performance. PDF
Cellulosic fibres provide a very agreeable environment for growth of bacteria due to large surfaces with high moisture absorbability. Therefore, the demand for an anti-microbial finish as an effective means of preventing disease transmission is high; it inhibits growth of or kills microorganisms on textile fabrics. This paper reports results of experiments where silver oxide (Ag2O) or zinc oxide (ZnO) was used as a catalyst with the halogenated phenoxy compound (Microfresh, MF) and a binder (Microban, MB) on cotton fabrics to improve treatment effectiveness and minimize its side effects. Anti-microbial-treated fabrics showed some new characteristic peaks in chemical structure as evaluated by Fourier Transform Infrared Spectroscopy. In an anti-microbial test, it was found that anti-bacterial activity increased as MF-MB chemical agents were applied to the fabrics. A noticeable result was that the metal oxide catalyst had a significant effect on enhancing the performance. Surface morphology of anti-microbial-treated cotton specimens showed roughened and wrinkled fabric surface with high deposition of the finishing agent, which had a lower breaking load and tearing strength resulting from side effects of the acidic treatment. However, the addition of the Ag2O catalyst was able to compensate for the reduction in tensile and tearing strength, and it is considered harmless for human skin. PDF
SO42-/ZrO2-TiO2 catalysts prepared by precipitation and impregnation methods were employed for glucose conversion. The basic structures of the prepared catalysts were characterized by XRD, BET, NH3-TPD, XPS, and TEM techniques. The essential properties of SO42-/ZrO2 could be improved greatly by adding a suitable amount of TiO2. High BET area and pore volume favored glucose conversion. The conversion rate of glucose into levulinic acid catalyzed by SO42-/ZrO2-TiO2 increased significantly in an extremely low acid system, indicating that the acidic condition was favorable for levulinic acid formation. The combined yield of 5-hydroxymethylfurfural and levulinic acid reached 28.8% with the presence of SO42-/ZrO2-TiO2 when the Zr-Ti molar ratio was 5:5 at 170°C for 2 h in the extremely low acid system. Studies on catalyst recycling were also further investigated in this study. PDF
This article investigates the effect of natural weathering on mechanical and morphological properties of rattan powder-filled natural rubber (NR) composites as a function of filler loading and silane coupling agent. The rattan powder samples in the range of 0 to 30 phr were compounded with NR using a laboratory size two-roll mill. The natural weathering test was carried out for six months. The degradation of the samples was evaluated by performing a tensile test, a Fourier transform infrared spectroscopy (FTIR), and a scanning electron microscopy (SEM) test. The results indicated that after natural weathering, an increase in stress at 100% elongation (M100) can be seen for samples without the silane coupling agent, whilst M100 was reduced for samples with silane coupling agent. A drastic reduction in tensile strength and elongation at break were observed for all samples due to the photo-oxidation process that occurred during the degradation of the samples. The extent of degradation on the samples’ surfaces and the presence of oxygenated products were confirmed by SEM and FTIR studies, respectively. PDF
Asgher, M., Irshad, M., and Iqbal, H. M. N. (2012). "Purification and characterization of LiP produced by Schyzophyllum commune IBL-06 using banana stalk in solid state cultures," BioRes. 7(3), 4012-4021.
Lignin peroxidase was produced from Schyzophyllum commune IBL-06 through solid state fermentation of an abundantly available agro-industrial waste, banana stalk, under pre-optimized conditions. LiP was fractionated by 65% saturation with NH4SO4 and dialysis to 1.5-fold purification. The enzyme was further purified by Sephadex G-100 gel filtration chromatography to 2.34 fold with specific activity of 468 U/mg. A single band of 80 kDa was obtained on native gel while on sodium dodecyl sulphate polyacrilamide gel electrophoresis (SDS-PAGE), and two bands having molecular weight of 33 & 47 kDa were obtained, suggesting that LiP was a two polypeptide oligomeric protein. The present LiP from S. commune IBL-06 was optimally active at pH 5 and 35oC. The stability assay showed that LiP retained activity in an acidic pH range of 4 to 6 and a temperature of 25 to 45°C after 24 h of incubation. Lignin peroxidase oxidized the vertry alcohol and showed kinetic constants KM and Vmax values of 0.46 mM and 388 mM/min, respectively. All organic and inorganic compounds inhibited S. commune LiP, but EDTA, β-Marcaptoethanol, and Pb(NO3)2 were the most inhibitory. PDF
Wu, J., Wang, H., Yang, X., Wan, J., Liu, P., Xu, Q., Tang, Y., and Zhang, X. (2012). "Dietary fiber production from sweet potato residue by solid state fermentation using the edible and medicinal fungus Schizophyllum commune," BioRes. 7(3), 4022-4030.
Dietary fiber (DF) has attracted increasing interest from nutritionists. The yield of DF by traditional extraction methods, however, is very low. This paper aims to increase the yield of DF by solid state fermentation using the edible and medicinal fungus Schizophyllum commune. Sweet potato residue (SPR) was selected as raw material for producing DF. Results showed that SPR was a good feedstock for DF production by solid state fermentation. Optimized conditions of solid state fermentation of SPR for DF were obtained as follows: material particle size = 1.8 mm to 2.5 mm, water moisture at 65%, natural lighting radiation, and temperature at 27 °C. Under the optimal conditions, the yield and DF content in fermented SPR were more than 80% and 70%, respectively. The increased DF yield was mainly attributable to increased cellulose and hemicelluloses conversion. Swelling capacity, water-holding capacity, oil-holding capacity, and glucose absorption capacity of the fermented SPR were also determined, and the data indicated that the fermented SPR could be considered as a new good DF. Therefore, this work showed us a novel bioconversion method to produce high-quality DF, and the yield of DF increased 4-fold compared with traditional extraction methods. PDF
Zhang, W., Liu, C., Wang, G., Ma, Y., Zhang, K., Zou, S., and Zhang, M. (2012). "Comparison of the expression in Saccharomyces cerevisiae of endoglucanase II from Trichoderma reesei and endoglucanase I from Aspergillus aculeatus," BioRes. 7(3), 4031-4045.
Two distinct expression cassettes were synthesized by overlapping PCR for expressing the endoglucanase I gene (egl1) from Aspergillus aculeatus and the endoglucanase II gene (egl2) from Trichoderma reesei in a Saccharomyces cerevisiae host. One contained the anchored sequence from the S. cerevisiae cwp2 gene, while the other did not. The low and high copy number plasmids YCplac33 and YEplac195 were used. The enzymatic activities and viscosity changes in the YP-CMC medium varied between the eight recombinant yeast strains produced, and the greatest values were obtained with the YE-TrEII’ strain, which had an activity of 347.7 U/g dry cell weight (DCW) and viscosity at 12 h of 4.7% of the initial control value, respectively; YE-TrEII’ was YEplac195-based and contained T. reesei egl2 and no Cwp2 sequence. Strains YC-AaEI and YC-TrEII showed the lowest enzyme activitiy (80.5 and 30.4 U/g DCW, respectively) and viscosity changes at 12 h (20.5 and 26.2% of the initial control viscosity, respectively), which were YCplac33-based and contained the Cwp2 sequence. The results showed that gene copy number was the most significant factor to influence the expression of endoglucanases in S. cerevisiae, and the existence of Cwp2 sequence led to decreased enzymatic level and viscosity-reducing performance, while it was shown not to realize efficient surface display of these two endoglucanases. PDF
The aim of the present work was to find an optimum kraft pulping process for olive tree pruning (OTP) in order to produce a bleachable grade pulp of Kappa number about 17. The kraft pulp produced under optimized conditions showed a viscosity of 31.5 mPa.s and good physical, mechanical, and optical properties, which are acceptable for paper grade production. The strength and optical properties were measured on pulps unrefined and refined in a PFI mill with up to 2000 revolutions before and after bleaching. The OTP pulp was bleached to 90% ISO brightness (kappa < 1); however the process demanded a long sequence of stages, OD(EP)D(EP)D, and a higher than usual total chemical dosage (24.78 kg/odt pulp). Overall, OTP is suggested as an interesting raw material for cellulosic pulp production because its properties are comparable to those of other agricultural residues currently used in the paper industry. PDF
Liao, W., Lai, Y.-C., Huang, C.-L., and Lien, C.-Y. (2012). "Characterization of physicochemical properties of Miscanthus floridulus stems and study of their oil absorption ability using gold nanoparticles," BioRes. 7(3), 4056-4066.
Miscanthus floridulus, which originated from a high elevation mountain area in Taiwan, is a newly cultivated species of Miscanthus. Instead of Miscanthus × giganteus, M. floridulus can be used as an alternative fuel for energy production as well. Except for leaves, stems of M. floridulus count for a major portion of the biomass. In this study, the lignin and cellulose contents of M. floridulus stems were determined to be 22.33 ± 2.21% and 43.13 ± 2.79%, respectively. In addition, a new application of M. floridulus stems was proposed. Oil absorption ability represented by the amount of soybean and motor oils absorbed by one gram of pulverized M. floridulus stems was estimated to be 2.25 ± 0.25 and 2.33 ± 0.18 g, respectively. Gold nanoparticles were used to investigate the absorption ability of M. floridulus stems. The absorption of gold nanoparticles by M. floridulus stems was visualized using SEM and TEM. In addition, the IR spectrum of M. floridulus stems was recorded for comparison with other studies. PDF
Bleached kraft semichemical eucalyptus pulp was used as raw material to adsorb an organic compound, toluene, from aqueous solution. The pulp was sonicated with different powers and different times to obtain smaller cellulose fibers. The adsorption capacity for toluene of sonicated fibers and bleached eucalyptus pulp was measured by ultraviolet spectroscopy. The absorption capacity for toluene was increased considerably when cellulose nanofibres were obtained. The adsorption capacity of bleached eucalyptus pulp was 36 μmol/g, while sonicated fibres at 30 W and 20 hours increased the adsorption by 47% and at 50 W and 20 h increased it by 67% compared with untreated fibres. Visual examination and optical microscopy were used to observe the reduction of fibers width and the dispersion increase. Contact angle measurements were used to analyze the variation of hydrophilic character of cellulose. Fourier transform infrared spectroscopy was used to study variations introduced by the ultrasound treatments on the chemical structure of the samples. The adsorption capacity studies showed that the treatment with ultrasound improved the retention capacity of the fibres, increasing considerably the adsorption capacity when the fiber width approached the nanoscale. PDF
The degradation kinetics of monosaccharides during sulfurous acid treatment was compared to hydrochloric acid and to sulfuric acid treatments. Reaction conditions corresponded to the range found in previous research to allow for the production of hemicelluloses-derived monosaccharides through hydrolysis of wood. Degradation behavior of monosaccharides during treatment with each acid was expressed by a second-order reaction rate constant with respect to substrate and acid concentrations, and the activation energy and frequency factor were calculated using the Arrhenius equation. Results demonstrated that the second-order reaction rate of a monosaccharide was dependent on the type of acid, indicating that monosaccharides degrade at different rates under different acids, even when the molar concentration of the acid is the same. The degradation of monosaccharides in sulfurous acid was much slower than that in hydrochloric acid and in sulfuric acid. A comparison of two sequential treatments with sulfuric acid, with and without the bisulfite ion, showed that sulfurous acid has a protective effect on the degradation of monosaccharides. PDF
Ncube, E., Chungu, D., Kamdem, D. P., and Musawa, K. (2012). "Use of a short span field test to evaluate termite resistance of Eucalyptus grandis and Bobgunnia madagascariensis in a tropical environment," BioRes. 7(3), 4098-4108.
Despite being treated with preservatives, the service life of transmission poles and fence posts in the Zambian Copperbelt province is close to fifteen years. However, the service life is only two years for untreated timber, mainly due to termite damage. This short service life is exerting more pressure on an already over-burdened timber resource base. This study used an accelerated field test investigation to facilitate initial assessment of several lesser known indigenous timbers for their termite resistance properties. To determine the service life and natural durability of Eucalyptus grandis and Bobgunnia madagascariensis to termite attack, samples of each wood species were field exposed to an aggressive species of subterranean termites for 32 days. Morphological and genetic analyses confirmed that the aggressive species of termites in this study was Coptotermes formosanus, commonly referred to as Formosan subterranean termites. Results indicated that E. grandis can be labeled as susceptible (S) following the standard natural durability rating procedure on the basis of service life projected from short term field exposure weight loss determination. Using short duration exposure weight loss and visual designation, similar to the Gulfport scale, B. madagascariensis was designated as very durable (D). These results showed that natural durability of timber against termites can be estimated after a short duration field exposure to Formosan subterranean termites. This method offers a fast field test for screening of promising lesser known tropical timbers. PDF
Flax fibres are being considered as an environmentally friendly alternative to synthetic fibres in fibre-reinforced polymer composites due to their low density, biodegradability, and high mechanical strength. Previous work has found that the surface properties of natural fibres can be modified by chemical treatment and other treatment methods. This study focused on the effect of different treatments using alkaline, enzyme, and steam-heat, respectively, on some surface characteristics of flax fibre, e.g. physical, chemical, and thermal stability. Using scanning electron microscopy (SEM), treated fibres were observed to have smoother surfaces than untreated fibres. Chemical composition of fibres was found to be modified after treatment as characterized by Fourier transform infrared spectroscopy (FTIR). The crystallinity index and thermal stability of flax fibres were increased after certain treatments as determined by X-ray diffraction (XRD) and thermogravimetric analysis (TGA), respectively. The wettability of treated fibre by water was improved compared to the untreated sample. PDF
Antiradical and antioxidant activities of ethanolic extract and its fractions from Calocedrus formosana Florin heartwood were investigated, and active compounds were identified by spectral analyses. Among extract and three fractions, the ethyl acetate soluble fraction had a high total phenolic content and exhibited the desirable reducing power, antiradical activity, and antioxidant activity. The compounds haplomyrfolin, O-ethyl-α-conidendral, matairesinol, 7,8-dehydro-4-O-methyl-thujaplicatin, and 5-methoxy-isosalicifoline were isolated from antioxidative activity guided fractionation of the ethyl acetate soluble fraction. Haplomyrfolin and O-ethyl-α-conidendral were for the first time isolated and identified from C. formosana. Matairesinol and 5-methoxy-isosalicifoline exhibited superior DPPH radical scavenging ability and antioxidant activity, as evaluated by TEAC assay. Results obtained in the present study revealed that ethyl acetate soluble fraction from C. formosana heartwood extract and its active compounds, matairesinol and 5-methoxy-isosalicifoline, exhibit antioxidant potential as natural nutraceuticals. PDF
Montmorillonite clay particles that had been prepared with an alklyl-ammonium surfactant were used to modify the moisture-sensitivity of bleached softwood kraft fibers through solvent exchange and adsorption methods. Moisture absorption and water uptake of the wood pulp fibers were significantly lower after the organo-nanoclay treatment. Thermal stability, surface energy, and surface morphology of the treated fibers were characterized using Thermogravimetric Analysis (TGA), Inverse Gas Chromatography (IGC), Scanning Electron Microscopy-Energy Dispersive X-ray Analysis (SEM-EDX), and Transmission Electron Microscopy (TEM) imaging. The Fourier Transform Infrared (FT-IR) spectral characteristics of the treated fibers were obtained to better understand the modified surface functional groups of the treated fibers. The treated bio-fibers had nano-scale surface roughness and a much reduced surface energy. The contact angle of water on the treated fiber mat was found to be higher than 160º. The thermal stability of the treated fibers was not affected by the modification. PDF
Dihydrocumic acid was prepared from β-pinene through oxidation and dehydration. Then, ten oxime esters from dihydrocumic acid were synthesized. Reaction conditions of the oxime esters were adjusted and their structures were characterized by IR, 1H-NMR, MS, and elemental analysis. The antibacterial activity of these newly synthesized oxime esters against Gram-negative bacteria and Gram-positive bacteria was also investigated using the inhibition zone method. The preliminary results indicated that seven compounds displayed better antibacterial activity against Gram-negative bacteria compared with bromogeramine, a commercially available antibacterial agent. PDF
The aim of this work was to study the potential application of four types of cereal straws: oats, maize, rapeseed, and barley, in order to obtain cellulose pulp through the Specel® process for use in the manufacture of 100% biodegradable and ecological packaging. Raw materials were chemically characterized to determine alcohol-extractives, ash, lignin, holocellulose, and α-cellulose. Cellulosic pulps obtained from raw materials were characterized to determine yield, Kappa number, and viscosity. Paper sheets made from cellulosic pulps were characterized to determine beating degree, tensile index, stretch, burst index, tear index, and brightness. Finally, the results were compared to the raw material used in the industrial manufacturing of packaging (wheat). The four studied raw materials (oats, maize, rapeseed, and barley) were judged to be suitable for use in the Specel® process to obtain cellulosic pulp suitable for production of ecological containers. PDF
The effects of pretreatment agents on pectin removal and chemical compositions in cotton stalk bark were studied. The results showed that the reaction rates of the depectinization agents reacting with calcium pectinate were VNa2C2O4 > VNa5P3O10 > VNaOH . The ratio of pectin removal reached 53.73% after pretreatment with 3% sodium oxalate. When the parameters of precondition were 3% sodium oxalate, 90 °C, and bleaching with 6.5% NaOH and 11% H2O2, the brightness of chemimechanical pulp from whole cotton stalk reached 76.18% ISO. PDF
To assess the feasibility of implementing hemicellulose recovery stages in kraft mills, Eucalyptus globulus wood samples were subjected to aqueous treatments with hot, compressed water (autohydrolysis processing) to achieve partial dissolution of xylan. Autohydrolyzed solids were subjected to kraft pulping under selected conditions to yield a pulp of low kappanumber, and to an optimized TCF bleaching sequence made up of three stages (alkaline oxygen delignification, chelating, and pressurized hydrogen peroxide), with minimized additions of pulping and bleaching chemicals. The final product had a relatively low kappa number (1.4), 641 mL/g ISO intrinsic viscosity, and 86.4% brightness. PDF
In the present work, a method for extracting cellulose from olive industry solid waste has been developed. The method involves subjecting solid olive waste to kraft pulping, followed by multistep bleaching processes. The totally free chlorine chemical bleaching sequence APEP was the most effective and gave an average cellulose yield of about 35%. The extracted cellulose was extensively characterized using FTIR, EMS, HPLC, and viscometry. Our key finding in this study is that the extracted cellulose was found to have physio-chemical properties that are similar to those of conventional microcrystalline cellulose (MCC). This is important, as our results show how lignocellulosic agricultural wastes can be utilized to produce high value cellulose powder. PDF
Steam explosion pretreatment of wheat straw can solubilize a significant portion of the hemicellulosic component and enhance the enzymatic digestibility of the remaining cellulose for fermentation into ethanol. In this work, wheat straw was pretreated by steam explosion using different steam temperatures and retention times, and the chemical compositions of the raw and steam-exploded wheat straw were analyzed. Results showed that the content of hemicellulose decreased sharply at higher steam temperatures and longer retention times; however, the content of lignin changed inconspicuously. After pretreatment, the characteristics of the straw fiber were investigated by studying their proportion of microfibrils, SEM, and FTIR. To assess the differences among various pretreatment parameters, the concentration of the reducing sugar and glucose conversion were determined. The highest reducing sugar concentration and glucose conversion were achieved at the explosion conditions of a pretreatment temperature of 220 ºC and a residence time of 3 min. PDF
Hot-water extraction of hemicelluloses, especially galactoglucomannans, from fractions of ground spruce wood with different particle sizes was studied at 170°C with extraction times up to 60 min. Extraction of spruce sapwood, heartwood, and thermomechanical pulp (TMP) was also compared at 160 to 180°C. Static batch extractions were carried out in an accelerated solvent extractor (ASE). The extracted hemicelluloses were characterized by sugar unit analysis and determination of acetyl groups and molar masses. The particle size significantly affected the extraction of ground wood. The total extraction yield, as well as the yields of hemicelluloses and monosaccharides, was the highest from the finest ground wood fraction (< 0.1 mm). The release of acetic acid, average molar mass of extracted hemicelluloses, and end-pH of the extracts were also dependent of the particle size, although to a lower extent. Irrespectively of the ground wood particle size, the yield of hemicelluloses reached a plateau after 40 min extraction at 170°C. The results indicate that extraction of hemicelluloses is limited mainly by the diffusion in the fiber wall, and for coarse wood shives also by the mass transfer in the wood matrix. There were only small differences in the hot-water extraction yields of hemicelluloses from spruce sapwood, heartwood, and TMP, considering both poly- and monosaccharides. PDF
Antifungal effects of geothermal fluids obtained from the Ankara, Afyon, Denizli, and Eskişehir regions of Turkey on white-rot (Trametes versicolor, MAD-697) and brown-rot (Coniophora puteana, FPRL 11E) fungus (Basidiomycetes) were studied. Fungal experiments were performed on kraft paper and Scots pine wood (Pinus sylvestris L.). We used non-concentrated geothermal water and concentrated geothermal water (via evaporation) in ratios of 25%, 50%, and 75%. To evaluate the results, we measured the concentration of specific minerals in the geothermal fluids such as boron (B), arsenic (As), copper (Cu), sulfate (SO4), sodium (Na), chloride (Cl), fluoride (F), potassium (K), and ammonia (NH3). The highest antifungal effect was observed for a geothermal fluid from the Denizli region, followed by Ankara, Afyon, and Eskişehir, in decreasing order. Antifungal properties of GFs are thought to be associated with the type and amount of mineral substances. In addition, the antifungal effects increased with increasing concentrations of geothermal water. PDF
Natural cotton fibers were pretreated with DMSO, NaOH, or ultrasonic waves and hydrolyzed by cellulase (Trichoderma vride G) to prepare nanocrystalline cellulose (NCC). The as-prepared samples were characterized by TEM, DLS, XRD, and FT-IR. The influences of the pretreatment on the yield and morphology of NCC were investigated. The alterations of the crystalline phase and chemical structure of NCC were also measured during the enzymolysis process. The experimental results proved that the pretreated cotton fibers could be hydrolyzed by the Trichoderma cellulase to prepare a nanosized strip (10 to 40 nm ´ 70 to 280 nm) and grainy (20 nm or 6 nm) crystalline cellulose, in which the different morphologies resulted from the different manners of pretreatment. The unaltered crystalline phase and chemical composition of NCC prepared by enzymolysis of pretreated cotton fibers were measured. The highest yield of NCC reached was 32.4%. PDF
Irshad, M., Bahadur, B. A., Anwar, Z., Yaqoob, M., Ijaz, A., and Iqbal, H. M. N. (2012). "Decolorization applicability of sol-gel matrix-immobilized laccase produced from Ganoderma leucidum using agro-industrial waste," BioRes. 7(3), 4249-4261.
With the extensive industrial applications of laccase in mind, this study was performed to investigate the decolorization applicability of sol-gel matrix-immobilized laccase. Indigenous G. leucidum laccase (592±6 U/mL) was purified 6.5-fold with a specific activity of 875 U/mg. The purified laccase had a molecular weight of 66 kDa, as evidenced by a single band on SDS-PAGE. Active laccase fractions were immobilized by entrapping in Sol-Gel matrix of trimethoxysilane (TMOS) and propyltetramethoxysilane (PTMS). A maximum of 90.7% immobilization efficiency was achieved with a purified fraction containing 2 mg/mL laccase. An activity profile revealed that immobilized laccase retained 78 to 80% of its original activity at a pH of 4 and a temperature of 80 °C, compared to free laccase. The tolerance capacity of laccase against inactivating agents (cystein, EDTA, and Ag+) was also enhanced by up to 80% by sol-gel immobilization. To explore the decolorization applicability, the immobilized laccase was tested against four different textile industry effluents. After the stipulated reaction time (24 h), varying decolorization percentages of wastewater effluents (with a maximum of 97.3% decolorization) were achieved. PDF
In response to increasing awareness of the environment and energy, the fields of application for new types of plant fiber functional materials are expanding. In this study, different weight proportions of coir fiber were added to wood particle debris to produce hybrid boards. The two forms of coir fiber used were random distribution and non-woven needle mat. A mixed orthogonal experiment was designed to use the weight mixing ratio of wood debris and coir, the density of the hybrid boards, and the mixing form of the raw material as the experimental factors. The mechanical and sound absorption performances were evaluated. The experimental results provided evidence that the addition of the coir fibers enhanced the mechanical performance and sound absorption performance of the hybrid boards. The non-woven needle mat form in particular was effective at evenly distributing the fibers. The optimal plan for this kind of hybrid composite was obtained through experimental analysis. The excellent sound absorption performance and sufficient strength of the hybrid boards made them suitable for use on inner walls as sound-absorbing material or on interior trim parts in automotive applications. The research results demonstrated the advantages of using coir fiber and wood debris resources. PDF
Defatted soy-based flour (DSF) modified with a combination of acid, salt, dicyandiamide, and alkali for preparing soy-based bio-adhesives (SBA) was investigated in this study. The resulting modified products from different reaction stages were characterized by FTIR, XPS, and TG. The results from FTIR and XPS indicated that the hydrolysis of the amide link and decarboxylation had occurred after the reaction by acid and salt; these reactions resulted in an increase of active groups, such as primary amine, carboxyl, and hydroxyl groups. The active groups were further increased by treatment with dicyandiamide and alkali. Curing the SBA resulted in the condensation and cross-linkage between active functional groups. Moreover, TG analysis proved that the active functional groups were increased during the modification process of the DSF, which was consistent with the results presented in FTIR and XPS. Finally, SBA was applied to plywood made from four wood species (basswood, Pinus massoniana, Triplochiton scleroxylon, and poplar) to test its water resistance performance. The average bonding strength between wood species was close to 0.91 MPa, which demonstrated that the SBA can be regarded as an alternative to petro-based adhesives. PDF
Liu, Y., Wang, Z., Wang, J., Yang, G., Huang, F., and Lucia, L. (2012). "Evaluation of the structural and molecular weight changes of lignin during the treatment of hardwood alkaline peroxide mechanical pulp with laccase and a laccase-mediator-system," BioRes. 7(3), 4284-4293.
Alkaline Peroxide Mechanical Pulp (APMP) of triploid of Populus tomentosa was modified by laccase and a Laccase-Mediator-System (LMS). The influence of the following main variables on the pulp physical properties were studied: enzyme dosage, reaction time, treatment temperature, and pH. Under the optimum conditions of laccase treatment – pH 5, temperature 50°C, pulp consistency 4%, and a reaction time of 60 min – the optimum charge of laccase was 2u/g. It was also found that the tensile strength and tear indices of the pulps treated with laccase increased significantly. The two-stage method of enzyme-mild acidic hydrolysis was adopted to isolate lignin from the APMP pulps both before and after enzymatic treatments. The functional groups in all lignin samples were qualitatively and quantitatively analyzed with 31P-NMR spectra. The molecular weight distributions of all the lignin samples were obtained through Gel Permeation Chromatography (GPC) after the lignin samples were benzoylated. PDF
Growing attention has been paid to the innovation of ecological products, prompted by rising environmental concerns. As a natural polymer, thermoplastic sago starch has been regarded as an alternative material to petroleum-based plastic owing to its availability, cost, and biodegradability. In order to produce thermoplastic starch materials with enhanced structural and functional stability during use, kenaf fibers were incorporated as the reinforcing filler. In this work, thermoplastic sago starch (TPSS)/kenaf core fiber (KF) biocomposites were prepared at different fiber loadings (0 to 35 wt.%), and the effects of fiber loading were analyzed by mechanical tests, TGA, FTIR, SEM, and water absorption behavior. The tensile analysis showed a linear increase in strength and modulus upon increasing fiber content until it reached an optimum at 30 wt.% fiber loading. The thermal stability of biocomposites was improved slightly by the incorporation of kenaf fibers into TPSS matrices. FTIR results indicated a change in the functional group of the biocomposites. Moreover, the interfacial adhesion properties of biocomposites were evident from morphological studies of tensile fracture surfaces. It is interesting to note that water absorbed by the biocomposites was reduced by the addition of fiber, and it seems that the hydrophilic character was decreased especially for the glycerol-plasticized sample. The results obtained clearly illustrate the potential use of these fiber and biopolymers to establish their suitability as alternative biocomposite materials. PDF
Waste newspaper fiber (WNF) was separated and deinked for use as an absorbent for removal of Malachite Green (MG) from aqueous solutions. The chemical composition of the deinked waste newspaper fiber (DWNF) was analyzed, and its morphology was observed by Scanning Electron Microscopy (SEM). A batch adsorption study was conducted under various adsorbent dosage, solution pH, and contact time. Kinetics and isotherms models were fitted; the thermodynamic parameters were also calculated. The results indicated that the main component in DWNF is cellulose. The SEM photographs showed that the surface became smoother and cleaner after deinking treatment. The equilibrium adsorption capacity was reached within 60 min, and the maximum adsorption capacity was around 27 mg/g. Alkaline pH (around 8) favored the adsorption process. The adsorption of MG was a spontaneous and exothermic process. It was found that the pseudo-second order kinetic equation and Langmuir adsorption isotherm model described the data of dye adsorption onto DWNF very well. The results show that DWNF is an effective absorbent for dye wastewater treatment. PDF
Calcium hydroxide filler dispersions, of various particle sizes, were prepared by mixing sodium hydroxide with calcium chloride, in various concentrations, at room temperature. The resulting filler dispersions were added, in various amounts, to the banana stem mechanical pulp, which was then converted to handsheets. Increasing the filler loading increased the tensile index but reduced the tear index and water absorption of the handsheets. The SEM micrographs of the handsheets surfaces and the tensile fractured surfaces of the handsheets tensile test specimens showed that increasing the filler loading resulted in the formation of more and bigger filler aggregates in the spaces between the fibre. The filler particle size did not have any significant effect on the handsheets properties. PDF
Laminated veneer lumbers (LVLs) were manufactured from half-round sliced I-214 hybrid poplar clone veneers with MUF adhesives using press pressures ranging from 2.5 to 15 kg cm-2. The results showed that the press pressures affected the glue line thickness (GLT) and the physical and mechanical properties of the LVLs. Higher specific gravity (SG) and mechanical properties, but lower GLT were developed as a result of using higher press pressures. The optimum press pressure was found to be 10 kg cm-2 in relation to GLT, SG, and mechanical properties. Significant linear correlations were found between GLT and mechanical properties. GLT can be used to determine the quality of wood bonding and may become a valuable tool for this purpose. Reliable data on the optimum GLT and press pressures can be used to design safe wood bonding applications in all aspects of wood based composites, as well as wood constructions when appropriate techniques are adopted to measure the GLT. PDF
Bark and the tops of E. globulus trees were considered for kraft pulping under industrial conditions. Pulping experiments included wood, bark, tops, and composite samples. Top wood had an average chemical composition most similar to that of wood but with somewhat lower cellulose content (52.8% vs. 56.9%) and higher lignin content (18.8% vs. 17.8%). There was also a small difference between tops and wood for non-polar extractives, which were higher for tops (2.0% vs. 1.4%). Bark had a less favorable chemical composition with more extractives, especially polar extractives (5.3% vs. 1.6%) and 1% NaOH solubility (19.9% vs. 12.2%), pentosans (23.7% vs. 21.3%), and ash (2.9% vs. 1.0%), although the fiber length was higher (1.12 mm vs. 0.98 mm). The kraft pulps obtained using bark showed significantly lower yield, delignification degree, and strength properties but had a quicker response to refining. The incorporation of tops and bark in the wood pulping in levels below or similar to a corresponding whole-stem, however, had a limited effect on pulp yield, kappa number, refining, and pulp strength properties. These additional raw-materials, which were estimated to be 26% of the commercial stem wood (14% bark and 12% tops), may therefore be considered in enlarging the eucalypt fiber feedstock in kraft pulping. PDF
A multiple linear regression analysis was carried out to predict the length of pellets under compression in the die based on moisture, temperature, pressure, hold time, and their interaction terms. Excellent correlations were obtained in the dependency of the considered parameters on length of compressed material inside the die. Springback characteristics based on axial changes after the compaction process were analyzed. The expansion for hardwood pellets (16.28%) was found to be lowest at particle size 0.150 to 0.300 mm with 8% moisture (w.b), 60 °C, 139.3 MPa pressure, and a hold time of 15S. The expansion for softwood pellets (20.56%) was lowest with particle size 0.300 to 0.425 mm, at 8% moisture (w.b), 70 °C, 159.2 MPa, and a hold time of 30S. PDF
Mohamad Ibrahim, M. N., Sriprasanthi, R. B., Shamsudeen, S., Adam, F., and Bhawani, S. A. (2012). "A concise review of the natural existance, synthesis, properties, and applications of syringaldehyde," BioRes. 7(3), 4377-4399.
Syringaldehyde is a promising aromatic aldehyde that no longer deserves to remain in obscurity. It possesses worthy bioactive properties and is, therefore, used in pharmaceuticals, food, cosmetics, textiles, pulp and paper industries, and even in biological control applications. Mostly, the synthetic form of syringaldehyde is being used. This review serves as an appraisal of potential research and commercialization of naturally occurring syringaldehyde beyond the scope of the food and cosmetic industries. This article also provides a comprehensive account of the various conventional extraction and chromatographic techniques used in the separation, isolation, and quantification of syringaldehyde. Further, to understand this unique compound, a brief outline on the natural formation of syringaldehyde in lignin is accentuated in this article. PDF
Suhaily, S. S., Jawaid, M., Abdul Khalil, H. P. S., Mohamed, A. R., and Ibrahim, F. (2012). "A review of oil palm biocomposites for furniture design and applications: Potential and challenges," BioRes. 7(3), 4400-4423.
This review considers the potential and challenges of using agro-based oil palm biomasses, including the trunk, frond, empty fruit bunch, and palm press fiber biocomposites, for furniture applications. Currently, design and quality rather than price are becoming the primary concern for consumers when buying new furniture. Within this context, this paper focuses on the design of innovative, sustainable furniture from agro-based biocomposites to meet the needs of future population growth and technology. This research also discusses the need for biocomposite materials that do not depend on the growth of populations, but on the growth and development of the economy. This study focuses on globally available agro-based biocomposites, especially those from oil palm biomass: plywood, medium density fiberboard (MDF), wood plastic composite (WPC), laminated veneer lumber (LVL), oriented strand board (OSB), hardboards, and particleboard. Additional positive aspects of biocomposites are their environmentally friendly character, high quality, competitive design, and capacity to improve the value proposition of high-end products. These attributes increase the demand for agro-based biocomposite furniture on the international market. PDF
Fibre-based packaging materials are widely utilized all over the world. They have several important advantages in comparison with fossil-based packaging: biodegradability, recyclability, and renewability. However, fibre-based packaging cannot fully compete with plastic in its barrier properties. Also there are limitations regarding its shapes due to poorer formability. The deep-drawing forming process can be used for the production of advanced three-dimensional shapes from paper-based materials. Formability and related characteristics are essential for deep-drawing of paper-based materials. This paper aims to give an overview of the deep-drawing of paper-based materials with the emphasis on the experienced deformations, on the role of mechanical properties of materials in deep-drawing, and on the typical defects found in the shapes after the forming. Additionally, strategies are proposed to help mitigate common problems in deep-drawing. PDF
The depletion of fossil fuels and the need to reduce greenhouse gas emissions has resulted in a strong growth of biomass utilization for heat and power production. Attempts to overcome the poor handling properties of biomass, i.e. its low bulk density and inhomogeneous structure, have resulted in an increasing interest in biomass densification technologies, such as pelletization and briquetting. The global pellet market has developed quickly, and strong growth is expected for the coming years. Due to an increase in demand for biomass, the traditionally used wood residues from sawmills and pulp and paper industry are not sufficient to meet future needs. An extended raw material base consisting of a broad variety of fibrous residues from agriculture and food industries, as well as thermal pre-treatment processes, provides new challenges for the pellet industry. Pellet production has been an established process for several decades, but only in the past five years has there been significant progress made to understand the key factors affecting pelletizing processes. A good understanding about the pelletizing process, especially the processing parameters and their effect on pellet formation and bonding are important for process and product optimization. The present review provides a comprehensive overview of the latest insights into the biomass pelletization processes, such as the forces involved in the pelletizing processes, modeling, bonding, and adhesive mechanisms. Furthermore, thermal pretreatment of the biomass, i.e. torrefaction and other thermal treatment to enhance the fuel properties of biomass pellets are discussed. PDF