Our peer-reviewed sister journal: Lignocellulose
BioResources, Volume 9, Issue 1
NOTE: Each current issue of BioResources continues to build as new articles are approved.
Successful applied research into wood bioenergy requires communication of meaningful insights to inform decision-makers and the general public. Effective communication strategies make such insights accessible. However, recent media reports often exhibit a near total absence of findings from peer-reviewed or quantitative research, highlighting a failure to communicate between applied researchers and reporters. As a result, the general public’s understanding of wood-based bioenergy remains incomplete. At a minimum, researchers can address three common lapses when communicating results of their research related to wood-based energy to increase the public’s access to technical results. First, provide context to give policymakers a sense, on a relative basis, of the importance of a given issue. Second, properly distinguish between “causal” relationships and mere happenstance or correlations. And finally, confirm facts and conclusions. Faulty assertions can cast doubts on the broader work and body of research. PDF
Investigators wanting to study aspects of wood machining face many challenges. The material under investigation is inherently different with respect to its three major axes, and it responds in various ways to local temperature, moisture, and many other variables. Researchers proposing future research projects in this area thus face a critically important task of selecting parameters to include either as variables or as quantities to hold constant. This editorial outlines key parameters and conditions of wood machining that can be considered, depending on the scope of a project. PDF
Interest in using kapok (Ceiba pentandra L.)–based cellulose in composite preparation is growing due to its advantages, including cost- effectiveness, light weight, non-toxicity, and biodegradability. In this study, chloroform, sodium chlorite, and sodium hydroxide were used for wax removal, delignification, and hemicellulose removal, respectively. It was observed that the air entrapment inside kapok fiber disappeared after it was treated with alkali. The structure became completely flattened and similar to a flat ribbon-like shape when examined using a vapour pressure scanning electron microscope (VPSEM). Fourier transform infrared (FTIR) spectroscopy was used to characterize the untreated and treated kapok fibers. The peak at 898 cm−1, which is attributed to the glucose ring stretching in cellulose, was observed for the obtained cellulose samples. Peaks corresponding to lignin (1505 and 1597 cm-1) and hemicellulose (1737 and 1248 cm-1) disappeared. The results of differential scanning colorimetry (DSC) indicated that the degradation of cellulose appeared as an exothermic peak at about 300 to 350 °C. The activation energy for thermal decomposition of kapok cellulose and its hemicelluloses was 185 kJ/mol and 110 kJ/mol, respectively. The activation energy for thermal decomposition can be used as an alternative approach to determine the purity of cellulose. PDF
Feng, L., Qin, L., Liu, Z.-H., Dong, C.-Y., Li, B.-Z., and Yuan, Y.-J. (2014). "Combined severity during pretreatment chemical and temperature on the saccharification of wheat straw using acids and alkalis of differing strength," BioRes. 9(1), 24-38.
Acids and alkalis are considered important catalysts in biomass pretreatment, which is essential to overcome the recalcitrance of lignocellulose for sugar release. In this study, the effects of various chemicals and temperatures on the pretreatment and subsequent enzymatic hydrolysis of wheat straw were investigated. The conversions of glucan and xylan during pretreatment and enzymatic hydrolysis were examined. The temperature and different ions in pretreatment govern the dissociation constant and hydrogen ion concentration. Due to higher dissociation at higher temperature, weak acids and weak alkalis can produce high glucose yields, similar to strong acids and alkalis. The concept of modified combined severity for weak acid pretreatment was explored. The pH value and real combined severity of weak acids at reaction temperatures were estimated according to xylan recovery during pretreatment. Glucose yield in enzymatic hydrolysis is mainly decided by xylan recovery for acidic pretreatment and by total content of xylan and acid-insoluble-lignin in solids for alkaline pretreatment. PDF
Starch microparticles (SM) were prepared by delivering ethanol as the precipitant into a starch paste solution dropwise. Chemically modified starch microparticles (CSM) were fabricated by a reaction with malic acid using the dry-preparation technique. Composites were prepared using CSM and various cellulose materials as fillers within glycerol plasticized–corn starch matrix through the casting process. Microcrystalline cellulose (MC, as reference filler) and two cellulose-enriched materials, namely Asclepias syriaca L. seed hairs (ASSH) and Populus alba L. seed hairs (PSH), were compared in terms of morphology and performance when incorporated within the CSM/S thermoplastic matrix. The effects of cellulose fillers on the morphology, surface, water sorption, and mechanical properties were investigated. The surface water resistance of composite materials was slightly improved through addition of cellulose fillers. Samples containing cellulose fillers presented higher tensile strength but lower elongation values compared with those without fillers. PDF
Liu, R., Peng, Y., Cao, J., and Luo, S. (2014). "Water absorption, dimensional stability, and mold susceptibility of organically-modified-montmorillonite modified wood flour/polypropylene composites," BioRes. 9(1), 54-65.
Wood flour (WF) was modified by sodium-montmorillonite (Na-MMT) and didecyl dimethyl ammonium chloride (DDAC) in a two-step process to form organically-modified-montmorillonite (OMMT) inside the WF with varied MMT concentration (0.25, 0.5, 0.75, and 1%, respectively). Then, the modified WF was mixed with polypropylene (PP) to produce WF/PP composites. The WF and WF/PP composites were characterized, and the water absorption, dimensional stabilities, and the mold susceptibility of the composites against Aspergillus niger, Penicillam citrinum, and Trichoderma viride were investigated. The results showed that Na-MMT was successfully transformed to OMMT inside WF. Owing to the hydrophobic nature and barrier effect of OMMT on water permeability, the composites showed some improvements in water resistance, dimensional stabilities and antibiotic performance. MMT concentration was also an important factor. The water repellency and dimensional stability were improved with increasing MMT concentration at first and then dropped after the MMT concentration exceeded 0.5%. However, the mold resistance of the composites increased along with increasing MMT concentration. With 1% MMT treated, the mold growth rating decreased to 1 (mold covering of 0-25%). These results suggested that OMMT modified WF had a positive effect on restricting water absorption, swelling, and mold susceptibility for the WF/PP composites. PDF
Koay, Y. S., Ahamad, I. S., Nourouzi, M. M., Abdullah, L. C., and Choong, T. S. Y. (2014). "Development of novel low-cost quaternized adsorbent from palm oil agriculture waste for reactive dye removal," BioRes. 9(1), 66-85.
An attempt was made to chemically modify palm kernel shell (MPKS) to increase adsorption affinity towards Reactive Black 5 (RB5). Granulated palm kernel shell (PKS) was quaternized successfully by treating with N-(3-chloro-2-hydroxypropyl)trimethylammonium chloride under alkaline conditions and was characterized. Surface characterization by Scanning Electron Microscopy (SEM) and BET analysis confirmed the surface pore enlargement from mesospores to macropores after modification. Fourier Transform-Infrared (FTIR) Spectrometer and CHN analysis revealed that the quaternary ammonia group (NR4+) was successfully reacted on MPKS fiber. pH 4 is the optimum for removal of RB5 on MPKS. Equilibrium isotherms were analyzed by the Langmuir, Freundlich, and Redlich-Peterson models. The Redlich-Peterson model was found to fit well with the data. The maximum adsorption capacity of MPKS was 207.5 mg/g for adsorption of RB5. PDF
Soltani, M., Veisi, R., Rohani, A. A., Ramzani, O., Naji, H. R., and Bakar, E. S. (2014). "UV-curable coating process on CMYK-printed duplex paperboard, Part 1: Mechanical and optical properties," BioRes. 9(1), 86-92.
An ultraviolet (UV)-curable coating is one of the best finishing methods in the paper and packaging industries for protecting ink layers from physical and mechanical defects. The purpose of this study was to investigate the mechanical and optical properties of CMYK printed paperboard after coating it with the UV-curable varnish. Commercial duplex paperboard (glazed grayback paperboard, 230 g/m2) was printed with a CMYK offset printing process. After conditioning the printed samples, they were coated with a commercial UV-curable varnish (consisting of a liquor-to-solvent ratio of 50:50) using an industrial screen-coating machine. The samples were then dried using a UV lamp in an industrial UV drying machine. The discoloration of the CMYK ink layers was measured spectrophotometrically using CIELab parameters (L*, a*, b*, and ΔE) before and after the coating process. The whiteness, brightness, and fold and tear resistance of the ink films were also measured. Color change (ΔE) was recorded for all tested samples, and the least amount of discoloration was observed in CYAN ink. The highest variances of the relative optical parameters were found in the MAGENTA, YELLOW, and BLACK ink ﬁlms, which resulted in yellowing of the coated paperboard. It can therefore be concluded that the coating process significantly decreased the fold and tear resistance of the samples. PDF
Lehto, J., Alén, R., and Malkavaara, P. (2014). "Multivariate correlation between analysis data on dissolved organic material from Scots pine (Pinus sylvestris) chips and their autohydrolysis pretreatment conditions," BioRes. 9(1), 93-104.
Various chemometric techniques were used to establish the relationship between the autohydrolysis conditions prior to pulping and the chemical compositions of the soluble organic materials removed from Scots pine (Pinus sylvestris) wood chips. The aqueous chip pre-treatments (autohydrolysis) were administered at 130 °C and 150 °C for 30, 60, 90, and 120 min, and the hydrolysates obtained were characterized in terms of total carbohydrates (various mono-, oligo-, and polysaccharides together with uronic acid side groups), volatile acids (acetic and formic acids), lignin, and furans (furfural and 5-(hydroxymethyl)furfural). Based on the analytical data gathered, a relatively accurate model for pine chip autohydrolysis was developed. PDF
Lanvermann, C., Hass, P., Wittel, F. K., and Niemz, P. (2014). "Mechanical properties of Norway spruce: Intra-ring variation and generic behavior of earlywood and latewood until failure," BioRes. 9(1), 105-119.
The alternating earlywood and latewood growth ring structure has a strong influence on the mechanical performance of Norway spruce. In the current study, tensile tests in the longitudinal and tangential directions were performed on a series of specimens representing one growth ring at varying relative humidities. All tested mechanical parameters, namely modulus of elasticity and ultimate tensile stress, followed the density distribution in the growth ring, with the minimum values in earlywood and the maximum values in latewood. The samples were conditioned at three relative humidity levels 50%, 65%, and 95%. With increasing relative humidity, the values of the mechanical parameters were found to decrease. However, due to the high local variability, this decrease was not statistically significant. The test in the tangential direction on a set of earlywood and latewood specimens at 65% relative humidity revealed a similar limit of linear elasticity for both early- and latewood. Where the strength of both tissues was equal, the strain at failure was significantly greater for earlywood. Furthermore, the portion of the non-linear stress/strain behavior for earlywood was significantly greater. A Weibull analysis on the ultimate tensile strength revealed a tissue-independent Weibull modulus, which indicates similar defect distributions. For both, the failure occurred in the middle lamella. PDF
Cheng, D., Chen, L., Jiang, S., and Zhang, Q. (2014). "Oil uptake percentage in oil-heat-treated wood, its determination by Soxhlet extraction, and its effects on wood compression strength parallel to the grain," BioRes. 9(1), 120-131.
Oil heat treatment can effectively improve the dimensional stability and bio-durability of wood. However, the characteristics of high oil uptake (50 percent or higher) and high susceptibility to leaching from wood have an adverse effect on subsequent manufacturing processes of wood product and production costs. A solvent extraction (100% ethanol) process was used to extract the surplus oil from the treated wood. Because the making of powder specimens from high oil uptake wood would result in experimental error, a new method of determination of oil uptake percentage was proposed by two step Soxhlet extraction with ethanol. The oil uptake percentage of oil-heat-treated poplar wood at 180 °C for 2 h with this method was determined to be 113.29%. Additionally, the average oil uptake percentage (OUP) of oil-treated poplar after the oil extraction process for 2 and 6 h was 54.82% and 29.11%, respectively. Moreover, the average oil extraction percentage (OEP) of specimens with the oil extraction process at the first step (wood sticks) in the Soxhlet extractor apparatus was larger than that of oil-heat-treated poplar specimens. Due to the combined effect of chemical changes in the wood at high temperatures and of oil uptake by the wood, the compression strength parallel to the grain changed at different OUP levels. PDF
Industrial hemp is a non-wood fiber material that can be used for papermaking due to a high yield of hemp raw material and high-quality physical properties of its pulp. Hemp is already used as a raw materialfor papermaking and other industrial productions. The chemical composition of hemp root bast (HRB) was analyzed. HRBs were pulped using a soda-anthraquinone (Soda-AQ) process and bleached with oxygen (O), chlorine dioxide (D), and alkali (E) using the bleaching sequence OD0ED1. The results showed that HRB can be a suitable raw material for papermaking; the HRB pulp had a high viscosity (893 mL g-1) and brightness (85.52% ISO-brightness). PDF
Causticizing calcium carbonate (CCC), known as lime mud, is a by-product of the papermaking industry that comes from the green liquor causticizing process. In China, CCC has been used as a paper filler to replace precipitated calcium carbonate (PCC). This is beneficial for saving resources and preventing secondary pollution. Unfortunately, compared with PCC, CCC can reduce the sizing efficiency of alkyl ketene dimer (AKD). So the application scope and dosage of CCC has been limited in mill trials in China. In this study, CCC was prepared with green liquor and quicklime, which were obtained from an alkali recovery line of a pulping mill. The reason for the lower sizing efficiency of AKD when CCC was used as a filler was investigated. The results showed that when greater amounts of AKD were adsorbed by CCC, the AKD sizing efficiency was lower. The irregular CCC had higher Brunauer, Emmett, and Teller (BET ) surface area and Barrett-Joyner-Halenda (BJH) method cumulative desorption pore volume, resulting in higher adsorption. The spindle-like or needle-like CCC had lower BET surface area and BJH method cumulative desorption pore volume that was beneficial for controlling its adsorption of AKD and improving the sizing efficiency. PDF
Two new tree variants, namely Acacia hybrid and second-generation Acacia mangium, have been introduced in plantation forests in Sarawak, Malaysia, and their wood qualities were examined. The mean basic density of Acacia hybrid was comparable with Acacia mangium. However basic density and strength properties of second-generation A. mangium were significantly lower compared to Acacia hybrid. The mean fibre length and fibre wall thickness in the hybrid were found to be greater than that of second-generation A. mangium. Fibre diameter and fibre lumen diameter of Acacia hybrid were smaller compared to second-generation A. mangium. Runkel and slenderness ratios of Acacia hybrid and second-generation A. mangium fibres showed that they were suitable for pulp and paper production. Acacia hybrid was more resistant to Coptotermes curvignathus attack than second-generation A. mangium. A laboratory soil block test showed that Acacia hybrid and second-generation A. mangium were moderately durable timbers. In summary, marked differences in wood properties and qualities were observed between Acacia hybrid and second-generation A. mangium. PDF
Magnesium-based alkali is an attractive alkaline source for the peroxide bleaching of high-yield pulp. However, little information is available on Mg(OH)2 application in the final peroxide bleaching stage of wheat straw pulp. The use of Mg(OH)2 was demonstrated as a partial replacement for NaOH in the peroxide bleaching of a chelated oxygen-delignified wheat straw pulp. The yield, viscosity, and strength properties of bleached pulp significantly increased with increasing replacement ratio of Mg(OH)2, while the chemical oxygen demand load (COD) of filtrate was decreased. For similar brightness of bleached pulp at a 24% replacement ratio of Mg(OH)2, the tensile and tear indices were higher, by 2.1 Nm.g-1 and 1.75 mN*m2.g-1, respectively, than that of control pulp bleached with NaOH as the sole alkaline source. When the MgSO4 was eliminated and the dosage of Na2SiO3 was decreased in the bleaching process, the tear and burst indices of the bleached pulp were also enhanced, with the brightness maintained. Scanning electron microscopy (SEM) showed that more swelling occurred in the fibers of bleached pulp from the Mg(OH)2-based bleaching process. Fiber analysis indicated that peroxide bleaching with Mg(OH)2 increased the proportion of fiber lengths between 0.20 to 1.20 mm and 1.20 to 7.60 mm. PDF
Pyrolysis of olive oil industry wastes was carried out using stepwise isothermal fast pyrolysis (SIFP). SIFP consists of a succession of isothermal fast pyrolysis reactions in which the solid products obtained from the previous isothermal fast pyrolysis reaction become the substrates for subsequent reactions at higher temperatures. This article reports the results obtained from the SIFP of olive oil residue carried out between the temperatures of 300 and 500 °C using 100 °C intervals under reduced pressure (200 mm Hg). The maximum yield of liquid products occurred at 300 °C and consisted of around 35% bio-oil, which contained mainly phenols, furans, and fatty acid methyl esters (FAME). At 400 and 500 °C, FAME, which is derived from residual olive oil, was the major product. PDF
To reveal the structural changes of lignin during the soda–AQ cooking process and chemical bonds between lignin and xylan of wheat straw, 13C isotope-labeled technology was used in this study. First, 13C isotope-labeled xylose was injected into the living wheat straw. The success of 13C isotope-labeling was confirmed by the results of 13C abundance determination. Then, milled wood lignin-13C was extracted from wheat straw. The wheat straw, which had already been labeled by xylose-13C, was cooked by the soda-AQ process. Soda-AQ Lignin-13C and Residual Lignin-13C were extracted from black liquor and residual pulp. FT-IR, 13C-NMR, and 2D HSQC NMR analyses indicated that all lignin preparations were HGS-type lignin. The main lignin linkages were β-O-4’ units, β-β’ units, β-5’ units, and β-1 units, with the highest content of β-O-4’. Furthermore, 82.8% of β-O-4’ units, 77.2% of β-β’ units, 75.4% of β-5’ units, and 75.4% of β-1 units were degraded during the cooking process. LC bonds between lignin and xylan were at C2 and C5 positions of xylan. It was found that the C-2 position of xylan in wheat straw could be mainly connected to lignin by γ-ester bonds, and C-5 position of xylan in wheat straw was possibly linked with lignin by benzyl ether bonds. PDF
İmirzi, H. Ö., Ülker, O., and Burdurlu, E. (2014). "Effect of densification temperature and some surfacing techniques on the surface roughness of densified scots pine (Pinus sylvestris L.)," BioRes. 9(1), 191-209.
The effects of densification temperature, planing, circular sawing, and sanding on the surface roughness of densified Scots pine using the open-system thermodynamic method were studied. Densification was applied to Scots pine at 6 MPa pressure and at temperatures of 120 °C, 140 °C, and 160 °C. A total of 1040 specimens (160 × 50 × 10 mm) were prepared using the surfacing techniques of planing, circular sawing, and sanding. The surface roughness of the specimens were measured in conformance with the TS 2495, EN ISO 3274, and the TS 6212 EN ISO 4288 standards, and the results were subjected to statistical analysis. The surface roughness of the planed surfaces was 26% lower, of the surfaces cut circularly was 38% lower, and of the sanded surfaces was 32% lower in densified Scots pine compared to undensified Scots pine. According to the densification temperature, while the lowest roughness was obtained in the densified specimens at 140 °C, raising the temperature to 160 °C increased the roughness. An increase in the number of blades in planing, the tooth number in circular sawing, and the grit number in planing decreased the surface roughness. Furthermore, the roughness was less in tangential surfaces compared to radial surfaces. PDF
Cellulose nanocrystals (CNCs), also called cellulose nanowhiskers, cellulose nanorods, or nanocrystalline cellulose, were prepared from Phyllostachys heterocycla using a commercial cellulase for hydrolysis. The enzymatic hydrolysis process and application performance as well as the biocompatibility of the CNCs were investigated. Here, the cellulase hydrolysis conditions were optimized at a cellulase dosage of 0.01 mL/g dried fibers, a hydrolysis temperature of 60 °C, a hydrolysis time of 3 h, and a bamboo fiber concentration of 2 wt%. Under these conditions, the resultant CNCs retained more similarities to the original bamboo fibers than those fabricated by sulfuric acid hydrolysis. The product also demonstrated potential biocompatibility, which expands its applicability in the biopharmaceutical and biomedical fields. PDF
Alwani, M. S., Abdul Khalil, H. P. S., Sulaiman, O., Islam, M. N., and Dungani, R. (2014). "An approach to using agricultural waste fibres in biocomposites application: Thermogravimetric analysis and activation energy study," BioRes. 9(1), 218-230.
Thermal stability behaviour of coconut coir, banana pseudo stem, pineapple leaf, and sugarcane bagasse fibres was investigated under nitrogen atmosphere. The parameters of degradation kinetics were determined by thermogravimetric analysis at heating rates of 5, 10, 15, 20, 30, and 40 °C/min using the Kissinger, Flynn-Wall-Ozawa and Friedman model-free methods. Thermal degradation of these fibres showed both two and three mass loss steps attributed from the moisture evaporation and to the decomposition of cellulose, hemicelluloses, and lignin as well as other organic materials. The results also showed that activation energy was an increasing function of conversion (α), and an apparent activation energy of 75 to 200 kJ/mol was found for most of the fibres throughout the polymer processing temperature range. These findings are significant for developing a fundamental approach to understand the thermal decomposition behaviour of agricultural waste fibres in the course of biocomposite and bio-ethanol production. PDF
Xie, J., Huang, X., Qi, J., Hse, C.-Y., and Shupe, T. F. (2014). "Effect of anatomical characteristics and chemical components on microwave-assisted liquefaction of bamboo wastes," BioRes. 9(1), 231-240.
The epidermis layer waste (ELW) and the inner layer waste (ILW) were removed from Phyllostachys pubescens bamboo, and the anatomical characteristics and chemical components of these wastes were comparatively investigated. Both the ELW and ILW were subjected to a microwave-assisted liquefaction process to evaluate the relationship between bamboo properties and liquefaction behavior. The results indicated that higher vessel and parenchyma percentages and lower cellulose and lignin contents in ILW contributed to lower residue content, while higher fiber percentage and cellulose or lignin contents in ELW resulted in higher residue content. Recondensation took place during the liquefaction of ELW, which was indicated by small granules appearing on the liquefied residue surface according to SEM images. The intense bands corresponding to hemicellulose and lignin in the FT-IR spectrum of the liquefied ELW residue gave further evidence that the liquefaction of ELW is a complex solvolysis process involving simultaneous reactions of chemical degradation and recondensation. PDF
Wheat bran (WB) was subjected to processing with Aureobasidium pullulans (A. pullulans) under selected conditions to partially break down the xylan into soluble products (mainly feruloyl oligosaccharides, FOs). The objective of this study was to investigate the technology for one-step fermentation of WB by A. pullulans without melanin secretion to produce FOs as well as to determine their structural features and antioxidant activity. Initial pH, inoculation quantity, and fermentation temperature were found to be efficient for releasing FOs according to the Plackett-Burman design (PBD). Based on the D-Optimal design, a yield of 904 nmol of FOs / L of fermentation broth was obtained under optimal conditions of initial pH 6.0, inoculation quantity 4.50%, and fermentation temperature 29 oC. Purification of FOs was performed with alcohol precipitation and Amberlite XAD-2. GC, IR, and ESI-MS demonstrated that FOs consist of feruloyl arabinosyl xylopentose (FAX5, Mw986), feruloyl arabinosyl xylotetraose (FAX4, Mw854), feruloyl arabinosyl xylotriose (FAX3, Mw722), and feruloyl arabinosyl xylobiose (FAX2, Mw590). Increasing the FO dose led to increased activity of SOD and GSH-Px in serum of S180 tumor-bearing mice, while the level of MDA was reduced, thus improving its in vivo antioxidant activity. PDF
Hamzah, M. H., Che Man, H., Zainal Abidin, Z., and Jamaludin, H. (2014). "Comparison of citronella oil extraction methods from Cymbopogon nardus grass by ohmic-heated hydro-distillation, hydro-distillation, and steam distillation," BioRes. 9(1), 256-272.
A proposed method for citronella oil extraction was developed with the application of ohmic heated hydro-distillation. The objective was to compare the performance of three different extraction methods, viz. ohmic heated hydro-distillation, hydro-distillation, and steam distillation. The maximum amount of extracted oil yield by ohmic heated hydro-distillation was 7.64 mL/kWh as compared to hydro-distillation and steam distillation methods that resulted oil yields of 3.87 mL/kWh and 1.69 mL/kWh, respectively. The kinetics of extraction followed a second-order model. Gas chromatography-mass spectrometry analysis found that the major constituents of citronella oil (GC-MS) for the different extraction methods were citronellal, citronellol, and geraniol. Scanning electron microscopy (SEM) of citronella grass provided evidence that the lignocellulosic sources of the extracted citronella oil were schizogenous cavities and cellular lignin. The citronella that had undergone ohmic-heated hydro-distillation and steam distillation showed some microfractures and less cell wall degradation than hydro-distillation. The cell walls were less rigid using ohmic-heated hydro-distillation compared to steam distillation. However, the cell walls of the hydro-distillation sample were less dense and exhibited pronounced swelling, but did not show any microfractures. PDF
Laireiter, C. M., Schnabel, T., Köck, A., Stalzer, P., Petutschnigg, A., Oostingh, G. J., Hell, M. (2014). "Active anti-microbial effects of larch and pine wood on four bacterial strains," BioRes. 9(1), 273-281.
Active anti-microbial effects of larch (Larix decidua Mill.) and pine (Pinus sylvestris L.) wood materials on Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecium, and Bacillus subtilis were tested. The agar-diffusion test, a method used in routine diagnostics, was implemented to detect anti-microbial effects of wooden discs and filter paper discs containing methanol extracts of different wood parts. The results showed that the bark of larch had an inhibitory effect on Staphylococcus aureus, and the heart wood of pine showed a significant anti-microbial effect on the gram-positive bacteria tested (Staphylococcus aureus, Enterococcus faecium, and Bacillus subtilis). These results were confirmed by using methanol-extracts. An anti-microbial activity against Pseudomonas aeruginosa was not found. Anti-bacterial effects of other parts of larch wood and of pine sapwood were also not found. The results of this study showed for the first time that certain parts of wood contain compounds that directly reduce microbial growth. These data are a further demonstration of the positive effects of specific wood species and could promote the usage of wood in hygienically sensitive areas. PDF
This study’s main objective was the dissolution of cellulose from biomass using ionic liquids to obtain saccharides by prehydrolysis. Raw materials were exposed to the ionic liquids (ILs) 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, 1-ethyl-2,3-dimethyl-imidazolium chloride, and 3-(2-methoxy-2-oxoethyl)-1-(3-methoxy-3-oxo-propyl)-imidazolium bromide at 105 °C for 6 h. The sugar content of the liquid phase was characterized by high-performance liquid chromatography (HPLC). The vegetal materials after treatments were characterized by Fourier transform infrared spectroscopy (FTIR). Glucose was the main reducing sugar product in each case. Different ILs were found to be most effective, depending on what sample was being dissolved – microcrystalline cellulose or rapeseed stalk. PDF
Zanuncio, A. J. V., Motta, J. P., Silveira, T. A., Farias, E. D. S., Trugilho, P. F. (2014). "Physical and colorimetric changes in Eucalyptus grandis wood after heat treatment," BioRes. 9(1), 293-302.
Planted forests can meet the world’s demand for wood. In Brazil, eucalypt species are cultivated on a large scale, but their dimensional instability and color limit their use, which makes heat treatment necessary. The aim of this study was to evaluate physical and colorimetric properties of Eucalyptus grandis after heat treatment at 140, 170, 200, and 230 °C for 3 h. Mass loss, shrinkage, equilibrium moisture content, volumetric swelling, fiber saturation point (FSP), and colorimetric parameters were determined; photos were also taken with a scanning electron microscope for all treatments. Heat treatment reduced the wood mass by 0.33 to 10.64% and caused shrinkage by 0.23 to 5.16%. Treatment at 230 °C reduced oven dry density. Equilibrium moisture content was 9.40, 9.34, 8.55, 6.55, and 5.05% for control and test samples treated at 140, 170, 200, and 230 °C, respectively. Heat treatment reduced thickness swelling and FSP by 59.65% and 56.31%, respectively. Heat treatment also reduced the L* (lightness), a* (green–red coordinate), and b* (blue–yellow coordinate) values of the wood samples. Heat treatment improved physical properties and darkened the wood; however, the damage observed in scanning electron microscope images could reduce the mechanical properties of wood. PDF
Recently, much attention has been paid to the development of technologies that facilitate the conversion of biomass into platform chemicals such as 5-hydroxymethylfurfural (5-HMF). In this paper, a tin-containing silica molecular sieve (Sn-MCM-41) was found to act as a bifunctional heterogeneous catalyst for the efficient conversion of glucose into 5-HMF in ionic liquid. In the presence of [EMIM]Br, the yield of 5-HMF converted from glucose reached 70% at 110 °C after 4 h. During the reaction, the active center of the catalyst first catalyzed the isomerization of glucose into fructose and then the dehydration of fructose into 5-HMF. After the reaction, the heterogeneous catalyst Sn-MCM-41 could be easily recovered and reused without a significant loss in activity. The catalyst Sn-MCM-41 was also able to catalyze the conversion of fructose into 5-HMF at an 80% yield. Moreover, the low toxicity of the Sn-based catalyst makes the method a greener approach for the conversion of saccharides into 5-HMF. PDF
Mohd Zainudin, M. H., Hassan, M. A., Md Shah, U. K., Abdullah, N., Tokura, M., Yasueda, H., Shirai, Y., Sakai, K., and Samsu Baharuddin, A. (2014). "Bacterial community structure and biochemical changes associated with composting of lignocellulosic oil palm empty fruit bunch," BioRes. 9(1), 316-335.
Bacterial community structure and biochemical changes during the composting of lignocellulosic oil palm empty bunch (EFB) and palm oil mill effluent (POME) anaerobic sludge were studied by examining the succession of the bacterial community and its association with changes in lignocellulosic components by denaturing gradient gel electrophoresis (DGGE) and the 16S rRNA gene clone library. During composting, a major reduction in cellulose after 10 days from 50% to 19% and the carbon content from 44% to 27% towards the end of the 40-day composting period were observed. The C/N ratio also decreased. A drastic change in the bacterial community structure and diversity throughout the composting process was clearly observed using PCR-DGGE banding patterns. The bacterial community drastically shifted between the thermophilic and maturing stages. 16s rRNA clones belonging to the genera Bacillus, Exiguobacterium, Desemzia, and Planococcus were the dominant groups throughout composting. The species closely related to Solibacillus silvestris were found to be major contributors to changes in the lignocellulosic component. Clones identified as Thermobacillus xylanilyticus, Brachybacterium faecium, Cellulosimicrobium cellulans, Cellulomonas sp., and Thermobifida fusca, which are known to be lignocellulosic-degrading bacteria, were also detected and are believed to support the lignocellulose degradation. PDF
Abdul Aziz, A. S., Manaf, L. A., Che Man, H., and Kumar, N. S. (2014). "Kinetic modeling and isotherm studies for copper(II) adsorption onto palm oil boiler mill fly ash (POFA) as a natural low-cost adsorbent," BioRes. 9(1), 336-356.
Adsorption characteristics of palm oil boiler mill fly ash (POFA) for the removal of Cu(II) from aqueous solution were investigated using batch adsorption studies. The effects of relevant parameters such as contact time, solution pH, adsorbent dosage, and initial concentration of copper were examined. Fundamental batch investigations indicated that 90% of the Cu(II) was removed in the first 30 min, achieving equilibration after only 270 min of agitation. The Cu(II) uptake mechanism is particularly pH- and concentration-dependant, favoring a pH value of 6.0. A decrease in adsorption capacity (qe) with an increase in Cu(II) removal efficiency (RE %) was obtained as the adsorbent dosage increased. The adsorption behavior of Cu(II) fit well to the Langmuir isotherm, with a monolayer adsorption capacity of 17 mg/g. The applicability of the Langmuir isotherm suggested the formation of monolayer coverage of Cu(II) ions onto equivalent sites of the adsorbent. Kinetics experimental data followed the trend of pseudo second-order kinetics, which is consistent with chemisorption with intraparticle diffusion as one of the rate-determining steps. Therefore, this study indicates that POFA could be used successfully as a natural low-cost adsorbent for Cu(II) removal from aqueous solutions. PDF
Forest vegetation plays a crucial role in improving the ecological environment and maintaining the regional ecological balance. However, most studies pay little attention to the factors that can impact forest biomass carbon storage (FBCS). This research estimated the FBCS by combining relevant forest inventory data and models of continuous functions for biomass expansion factor. A modeling equation was then established and applied to examine the impact of socioeconomic factors on FBCS in Jiangsu, a coastal province in Eastern China, as a case study. The results showed that Jiangsu’s FBCS increased by 20.28 Tg from 2005 to 2010, showing a prominent carbon sink effect but with spatial imbalance among the changes in carbon storage. Jiangsu’s FBCS is significantly affected by land use factors (e.g., forest area and cultivated area), population factors (e.g., population density and urbanization), and economic development factors (e.g., GDP). Relatively speaking, the forest area and GDP had positive effects on FBCS, while cultivated area, population density, and urbanization had significant negative effects. PDF
This study evaluated the effect of microwave radiation on the fluid permeability and compression strength parallel to the grain of beech false heartwood. European beech (Fagus sylvatica L.) was selected, and samples of false heartwood with dimensions of 30×20×20 mm3 were used. The microwave treatment was carried out in a laboratory device at a frequency of 2.45 GHz. The testing samples were divided into three groups (untreated, treated at 20-s intervals, and treated at 30-s intervals). The permeability was measured in the axial direction using distilled water. The coefficient of specific permeability was calculated using Darcy’s law. The results showed that the coefficient of specific permeability increased by up to 159% in comparison with untreated samples. The compression strength parallel to the grain decreased by up to 15%. PDF
The reinforcement potential of novel nanocellulose-based scaffolding reinforcements composed of microfibrils 5 to 50 nm in diameter and several microns in length was investigated. The cellulose nanofibril reinforcement was used to produce a three-dimensional scaffolding. A hybrid two-step approach using vacuum pressure and hot pressing was used to integrate the nanocellulose reinforcements in a liquid molding process with an epoxy resin to manufacture composites containing fiber volume contents ranging from 0.6% to 7.5%. The mechanical properties were studied using three-point bending. The Shore-D hardness test and differential scanning calorimetry (DSC) were used to investigate the curing response and its relation to the mechanical properties. Dynamic mechanical analysis (DMA) with a three-point bend setup was used to investigate the viscoelastic behavior of the nanocellulose composite samples at various temperatures and dynamic loadings. The results using the proposed liquid resin manufacturing method for processing the nanocellulose composites showed an increased modulus and a lower strain-to-failure compared to neat resin. Dynamic testing showed a trend of lower tan delta peaks and a reduction in the glass transition temperature with the addition of nanocellulose reinforcement. PDF
Daystar, J., Gonzalez, R., Reeb, C., Venditti, R., Treasure, T., Abt, R., and Kelley, S. (2014). "Economics, environmental impacts, and supply chain analysis of cellulosic biomass for biofuels in the southern US: Pine, eucalyptus, unmanaged hardwoods, forest residues, switchgrass, and sweet sorghum," BioRes. 9(1), 393-444.
The production of six regionally important cellulosic biomass feedstocks, including pine, eucalyptus, unmanaged hardwoods, forest residues, switchgrass, and sweet sorghum, was analyzed using consistent life cycle methodologies and system boundaries to identify feedstocks with the lowest cost and environmental impacts. Supply chain analysis was performed for each feedstock, calculating costs and supply requirements for the production of 453,592 dry tonnes of biomass per year. Cradle-to-gate environmental impacts from these modeled supply systems were quantified for nine mid-point indicators using SimaPro 7.2 LCA software. Conversion of grassland to managed forest for bioenergy resulted in large reductions in GHG emissions due to carbon uptake associated with direct land use change. By contrast, converting forests to cropland resulted in large increases in GHG emissions. Production of forest-based feedstocks for biofuels resulted in lower delivered cost, lower greenhouse gas (GHG) emissions, and lower overall environmental impacts than the agricultural feedstocks studied. Forest residues had the lowest environmental impact and delivered cost per dry tonne. Using forest-based biomass feedstocks instead of agricultural feedstocks would result in lower cradle-to-gate environmental impacts and delivered biomass costs for biofuel production in the southern U.S. PDF
The main pentosan components of sugarcane bagasse, which can be subjected to alkaline hydrolysis, are xylose, arabinose, glucose, and galactose. The pentosan reaction mechanism was considered for alkali-treated bagasse with variation of temperature and time. The kinetics of pentosan degradation were studied concurrently at temperatures of 50 °C, 70 °C, and 90 °C, with a solid-liquid mass ratio of 1:15, a stirring speed of 500 revolutions/min, and different holding times for bagasse alkali pre-extraction. With respect to residual pentosan content and the losses of raw material, the hydrolysis rates of alkali pre-extraction and pentosan degradation reactions of bagasse all followed pseudo-first-order kinetic models. Finally, the main degradation activation energy was determined to be 20.86 KJ/mol, and the residual degradation activation energy was 28.75 KJ/mol according to the Arrhenius equation. PDF
Dungani, R., Islam, M. N., Abdul Khalil, H. P. S., Davoudpour, Y., and Rumidatul, A. (2014). "Modification of the inner part of the oil palm trunk (OPT) with oil palm shell (OPS) nanoparticles and phenol formaldehyde (PF) resin: Physical, mechanical, and thermal properties," BioRes. 9(1), 455-471.
This study was conducted to enhance the physical, mechanical, and thermal properties of the inner part of the oil palm trunk (IP-OPT) impregnated with oil palm shell (OPS) nanoparticles at various concentrations (0, 1, 3, 5, and 10%) and phenol formaldehyde (PF) resin. The PF concentration was 15% (w/w basis) throughout the study. The physical, mechanical, and thermal properties of the OPS nanoparticle-impregnated IP-OPT lumber were analyzed according to various standards. It was found that IP-OPT gained a significant percentage of weight (up to 35.3%) due to the treatment, leading to a density increase from 0.42 to 0.89 g/cm3. The water absorption was reduced by up to 24%, which reduced the swelling coefficient, and thus, the anti-swelling efficiency was increased significantly. The tensile and flexural strengths increased from 9.77 to 19.64 MPa and from 14.46 to 38.55 MPa, respectively. The tensile and flexural moduli increased from 2.67 to 3.51 GPa and from 4.35 to 4.95 GPa, respectively, while the elongation at break decreased from 7.83 to 6.42%. The impact strength also increased significantly, from 6.90 to 15.85 kJ/m2. In addition, the thermal stability of IP-OPT was improved by the impregnation of OPS nanoparticles. Thus, it can be concluded that the impregnation of IP-OPT with OPS nanoparticles might be a good treatment process for enhancing the properties of the IP-OPT. PDF
Five polyamine fixing agents with different molecular weights but slightly different charge densities were used to treat a deinked pulp. Their efficacy in controlling colloidal substances (CS) in the pulp was measured using focused beam reflectance measurements (FBRM). The objective was to determine if the colloidal substances were affected by the fixing agents by a “colloidal fixation” mechanism, i.e., colloidal particles being fixed onto pulp fiber in an un-agglomerated, single-particle state, or a “colloidal agglomeration” one, i.e., colloidal particles being coagulated by fixing agents into bigger agglomerates. The results showed that colloidal fixation does take place, especially for the polyamine with the smallest molecular weight. Among the five polyamines, it was found that higher molecular weights tended to result in more extensive colloidal agglomeration, but the effect of charge density was almost insignificant. Because it is efficient in differentiating between these two fixation mechanisms, FBRM is a powerful tool in screening different fixing agents. PDF
Nasser, R. A., Salem, M. Z. M., Al-Mefarrej, H. A., Abdel-Aal, M. A., and Soliman, S. S. (2014). "Fuel characteristics of vine prunings (Vitis vinifera L.) as a potential source for energy production," BioRes. 9(1), 482-496.
Seven varieties of vine prunings (Vitis vinifera L.)grown under Riyadh conditions were considered as renewable sources for fuelwood. Significant effects (P<0.01) were found for total extractives, benzene-ethanol extractives, cellulose, hemicellulose, lignin, cold water solubility, and hot water solubility among the seven vine varieties. Highly significant positive correlations (P<0.01) were observed between the higher heating value (HHV) and benzene-ethanol extractives (r=0.74) and lignin content (r=0.94). Additionally, elemental composition (C, H, N, O, and S) exhibited a significant effect on HV (P<0.01) and ash content of the seven vine varieties. There were highly significant positive correlations (P<0.01) between the HV and C (r=0.96) and H (r=0.93). Ash content showed a highly significant effect (P<0.01) on HV with a negative coefficient (r=-0.93). The heating value of vine prunings ranged from 18.74 to 19.19 MJ/kg, i.e. higher than some well-known biomass fuels. The results suggested that the vine prunings could be suitable as a source for energy production in Saudi Arabia. PDF
Starch of moso bamboo mainly exists in the elongated parenchyma cells, and it is difficult for amylase to enter moso bamboo and dissolve the starch. Therefore, the mould resistance capability of moso bamboo’s products cannot meet the need for bamboo to resist fungal decay. In this experiment, moso bamboo blocks were first treated at six levels of pressure and for six different treatment durations. The results showed that reducing sugar content was decreased dramatically from 0.92 mg/L to 0.19 mg/L and the starch content decreased from 1.18% to 0.96% when the pressure was increased from 0 psi to 100 psi. Regression analysis showed that the effects of an individual amylase reaction and individual pressure treatment on the starch or reducing sugar content were significant with a high correlation coefficient. Three traditional types of moso bamboo moulds (Aspergillus niger, Penicillium citrinum, and Trichoderma viride) were then used for mould resistance testing. The results revealed that the mould resistance capability of moso bamboo blocks could be greatly improved by the combined effect of enzyme activity and pressure treatment. Mould resistance was enhanced by increasing the pressure or prolonging the treatment time. This research could provide a new method for the protection of bamboo from mould attack. PDF
Mohamad Remli, N. A., Md Shah, U. K., Mohamad, R., and Abd-Aziz, S. (2014). "Effects of chemical and thermal pretreatments on the enzymatic saccharification of rice straw for sugars production," BioRes. 9(1), 510-522.
The effects of alkaline pretreatment with NaOH, KOH, Ca(OH)2, and NaOCl at varying temperatures and concentrations on the production of sugars, changes in the morphological structure, and the chemical composition of rice straw were evaluated. Enzymatic saccharification of 2% (w/v) KOH-treated rice straw with autoclaving at 121 °C, 15 psi, 20 min, gave a maximum yield of 59.90 g/L of reducing sugars, which was slightly higher than that of NaOH (55.48 g/L) with the same conditions. Chemical composition analysis of the rice straw showed that the cellulose content was increased to 71% and 66% after pretreatments with NaOH and KOH, respectively. Fourier Transform Infrared (FTIR) spectroscopy revealed that solubilization and removal of the lignin component also took place. The scanning electron microscope (SEM) analysis showed a marked change in the morphological structure of the treated rice straw compared to the untreated rice straw. These results suggested that pretreatment of rice straw with either 2% (w/v) NaOH or KOH at high temperature could be a promising pretreatment method for sugars production. PDF
Pesman, E., Imamoglu, S., Kalyoncu, E. E., and Kirci, H. (2014). "The effects of sodium percarbonate and perborate usage on pulping and flotation deinking instead of hydrogen peroxide," BioRes. 9(1), 523-536.
The main objective of this study was to evaluate the potential of sodium percarbonate and sodium perborate utilization during repulping of old news and magazine paper mixture. A series of experiments were performed to determine the effects of bleaching agents on ISO brightness and ink removal efficiency of pulp after flotation deinking. Conventionally, with other parameters are constant, the ISO brightness of pulp was increased from 45.24% to 54.10% and ink elimination ratio at 950 nm of pulp was increased to 69.12% with 1% sodium hydroxide and 1% (as active oxygen content) hydrogen peroxide usage. However, when sodium percarbonate was utilized instead of hydrogen peroxide (as 1% active oxygen content) without alkaline addition, the ISO brightness of the pulp was increased to 55.00%. Also, unlike the other bleaching agents, a favorable effect of sodium percarbonate on ink detachment was observed. The ink elimination ratio of floated pulp was increased to 74.31% with 1% (active oxygen) sodium percarbonate addition without alkaline usage. There were no additive effects of sodium perborate usage on brightness, and ERIC value of pulp could be determined. In this respect, sodium percarbonate utilization without sodium hydroxide addition was proposed for effective repulping, deinking, and prebleaching of waste papers, in a similar manner to the use of hydrogen peroxide. PDF
A study was designed to examine the practical effects on bending and compression perpendicular to the grain of heating and treatment with preservative agents. Red oak and sweetgum were steamed to an internal temperature of 71 °C. Samples were subsequently treated with creosote or ammoniacal copper zinc arsenate (ACZA) while still hot. Samples were tested in bending and compression perpendicular to the grain using ASTM standards. The data indicate no severe reduction in bending properties of red oak or of the compression properties of sweetgum or red oak heated and then treated with ACZA or creosote. PDF
High-value wood veneer is used in the furniture and automobile interior industries for decorative purposes. Due to mechanical restrictions, veneer application on surfaces is limited to simple shapes. In the last century, many approaches were developed to improve the moulding behaviour of veneer. However, all of these processes face several difficulties. Currently, water is primarily used for veneer plasticization, with the disadvantages of shrinkage and cracks due to drying. Furthermore, products often fail during material climate testing due to set recovery. Thus, a veneer modification process was considered combining plasticization, moulding, and shape fixation of veneer with reduced set recovery. To accomplish this, veneers were impregnated with furfuryl alcohol/maleic anhydride solutions to improve plasticization and moulding properties. Subsequently, veneers were moulded, and the realized shapes were fixed by temperature-induced acid-catalyzed polymerization. Due to the polymer in the cell wall, set recovery of all modified samples was noticeably reduced compared to reference samples plasticized with water prior to moulding. The degree of set recovery reduction due to modification varied with the modification intensity. Samples with higher weight percentage gain (WPG=126.4%) were more stable in the presence of moisture than samples with lower polymer yields (WPG=107.4%). PDF
Chen, F., Jiang, Z., Deng, J., Wang, G., Zhang, D., Zhao, Q., Cai, L., and Shi, S. Q. (2014). "Evaluation of the uniformity of density and mechanical properties of bamboo-bundle laminated veneer lumber (BLVL)," BioRes. 9(1), 554-565.
The objective of this study was to evaluate the uniformity of density distribution for Bamboo-bundle Laminated Veneer Lumber (BLVL) and its relationship to the stability of mechanical performance. A novel assembly style called one-piece veneer formation technology was developed to enhance the density uniformity, and four different density levels for BLVL were examined by X-ray scanning. The results indicated that the homogeneity of density, the stability of mechanical performance, and the mechanical properties for BLVL could be effectively improved by assembling the bamboo bundles into layers and then combining the layers to make the lumber. The density uniformity in width and thickness directions increased with increasing target density. A negatively linear correlation between density and Coefficient of Variation (COV) of MOR and shearing strength was observed. Partial correlation analysis revealed that when controlling for the variability of density, the linear relationship between density and the COV of MOR became insignificant, and the degree of linear correlation between density and the COV of shearing strength decreased. PDF
The aim of this study was to determine the influence of the application of glue, creating an elastic glue-line, on the deformation of wood-based panels asymmetrically veneered on one side with bamboo. The geometrical stability comparisons included multilayer composites used in the production of sliding doors, medium density fibreboard (MDF) panels, and chipboard used in the production of furniture. Chipboard panels retained their shape and stability after asymmetrical veneering, no matter which direction the veneer was placed in relation to the long edge. MDF boards retained their shape and stability only when they were veneered crosswise. The worst results were attained from composite boards, which bent in every case. PDF
Bamboo residues were subjected to a microwave-assisted liquefaction process for the production of crude bio-polyols (CBP). The fractionated bio-polyols (FBP) were obtained by the removal of lignin derivatives from the crude bio-polyols (CBP) using a simple method. Polyurethane (PU) foams were successfully prepared from both CBP and FBP. The object of this study was to evaluate the effect of lignin derivatives in bio-polyols on the physical properties, thermal stability, and microstructure of PU foams. The results revealed that the PU foam made from CBP had a higher density and superior thermal stability compared to that made from FBP; however, they were also much more fragile. Scanning electron microscope (SEM) images indicated that the lignin compounds in the CBP had impact on the structure of the PU foam. PDF
Zheng, C., Chen, P., Bao, S., Xia, J., and Sun, X. (2014). "Environmentally compatible synthesis of superparamagnetic magnetite (Fe3O4) nanoparticles with prehydrolysate from corn stover," BioRes. 9(1), 589-601.
An environmentally compatible and size-controlled method has been employed for synthesis of superparamagnetic magnetite nanoparticles with prehydrolysate from corn stover. Various characterizations involving X-ray diffraction (XRD), standard and high-resolution transmission electron microscopy (TEM and HRTEM), selected area electron diffraction (SAED), and thermogravimetric analysis (TGA) have integrally confirmed the formation of magnetite nanoparticles with homogeneous morphology and the formation mechanism of magnetite only from ferric precursor. Organic materials in the prehydrolysate act as a bifunctional agent: (1) a reducing agent to reduce ferric ions to prepare magnetite with the coexistence of ferric and ferrous ions; and (2) a coating agent to prevent particle growth and agglomeration and to promote the formation of nanoscale and superparamagnetic magnetite. The size of the magnetite nanoparticles can be easily controlled by tailoring the reducing sugar concentration, reaction time, or hydrothermal temperature. PDF
As the support for loading TiO2, bamboo-based activated carbon fibers (BACFs) were obtained from Phyllostachys pubescens Mazel after liquefaction using phenol, melt-spinning, curing carbonization, and H2O activation. TiO2/BACFs were prepared by the sol–gel method and characterized by SEM, XRD, FTIR, and XPS. Anatase TiO2 film with high photocatalytic activity was formed on the surface of BACFs, and the average crystallite size of the TiO2 film was 17 to 30 nm. The characteristic absorbance peaks of anatase TiO2 were observed at 1402 and 541 to 605 cm-1 on the infrared spectrum of TiO2/BACFs. The surface of TiO2/BACFs was mainly comprised of C–C, C–O, C=O, and Ti-O bonds. With increased calcination temperature, the contents of element Ti and Ti-O bonds of lattice oxygen on the surface of TiO2/BACFs increased and then decreased. The degradation rate of TiO2/BACFs for methylene blue (MB) solution reached more than 98% after 7 h of UV illumination. PDF
McGavin, R. L., Bailleres, H., Lane, F., Blackburn, D., Vega, M., and Ozarska, B. (2014). "Veneer recovery analysis of plantation eucalypt species using spindleless lathe technology," BioRes. 9(1), 613-627.
The Australian hardwood plantation industry is challenged to identify profitable markets for the sale of its wood fibre. The majority of the hardwood plantations already established in Australia have been managed for the production of pulpwood; however, interest exists to identify more profitable and value-added markets. As a consequence of a predominately pulpwood-focused management regime, this plantation resource contains a range of qualities and performance. Identifying alternative processing strategies and products that suit young plantation-grown hardwoods have proved challenging, with low product recoveries and/or unmarketable products as the outcome of many studies. Simple spindleless lathe technology was used to process 918 billets from six commercially important Australian hardwood species. The study has demonstrated that the production of rotary peeled veneer is an effective method for converting plantation hardwood trees. Recovery rates significantly higher than those reported for more traditional processing techniques (e.g., sawmilling) were achieved. Veneer visually graded to industry standards exhibited favourable recoveries suitable for the manufacture of structural products. PDF
Qin, W., Zheng, Z.-M., Kang, P., Dong, C., and Yang, Y. (2014). "Solution-sensitivity and comprehensive mechanism of lignin breakdown during the phosphoric acid-acetone pretreatment process," BioRes. 9(1), 628-641.
This work focused on the solution-sensitivity and the comprehensive mechanism of lignin breakdown during the phosphoric acid-acetone pretreatment process using density functional theory calculations. The structures and properties of a-O-4 lignin, β-5-3 lignin, and β-βlignin were detected, which showed that the bond length follows the order: a-O-4 bond < β-5-3 bond < β-βbond, but a-O-4 lignin is more sensitive to solvent molecule thanβ-β lignin and β-5-3 lignin. The decomposition mechanism of a-O-4 lignin, β-5-3 lignin, and β-β lignin in different solutions showed that a-O-4 lignin decomposes much more easily than β-5-3 lignin and β-β lignin, acting as the most accessible and susceptible point of lignin. Further, the selectivity of decomposition of lignin depends markedly on the synergy of solution and position. The physical origin of the structure-selectivity of lignin in different solution can be rationalized in terms of both thermodynamics and kinetics. The reactions investigated in this work constitute a large database for understanding the chemistry of a-O-4 lignin, β-5-3 lignin, and β-βlignin, and their decomposition in different solutions. PDF
The goal of this study was to prepare nanocomposites of rice straw coated with different percentages of Fe3O4 nanoparticles (Fe3O4-NPs) [1.0, 5.0, 10.0, and 20.0 wt. %]. In this process, the size of Fe3O4-NPs changed with varying volumes of NaOH (2M). The Fe3O4-NPs were precipitated with sodium hydroxide from a solution of Fe(II) and (III) chloride in water under ambient conditions and N2 gas by the quick precipitation method using urea as a stabilizer. The rice straw/Fe3O4 nanocomposites (NCs) prepared by this method had magnetic properties in percentages higher than ten (10 wt. %). When the volume of NaOH increased, Fe3O4-NPs with uniform size and better distribution could be prepared, which means that the size of the NPs decreased as the reducing agent was increased. Transmission electron microscopy (TEM) showed that Fe3O4-NPs in rice straw were spherical with diameters from 18.47 to 9.93 nm. The SEM results show that the structure of rice straw underwent no particular change. EDX indicated the presence of Fe3O4-NPs on the surface of rice straw. X-ray powder diffraction (PXRD) indicated that the magnetic Fe3O4-NPs were pure and that the particles were small. The FT-IR results showed that the Fe3O4-NPs were successfully coated on the surface of rice straw. PDF
Oil palm trunks are a by-product of oil palm plantations and provide raw material to the woodworking industries. However, their resistance against degradation by termites needs to be improved; this study investigated hot pressing as a chemical-free method to improve resistance. The main objective was to assess resistance to termites conferred to oil palm wood by hot pressing at various temperatures (140, 180, and 220 °C) for a fixed duration of 8 min and maximum pressure of 2 MPa. The samples were the only available nutrition to subterranean termites (Coptotermes gestroi Wasmann) in a 4-week no-choice test. The thermally compressed oil palm wood did not show any significant effect of the pressing temperature on mass loss, but the surface damage to the samples with treatment at 220 °C indicated improved resistance to subterranean termites based on visual observation. PDF
Jiang, G.-q., Fang, G.-z., Li, L.-l., Shi, Z.-x., and Zhang, Z.-r. (2014). "Study on antioxidant activity of catalyzed hydrogen degradation product of polymeric proanthocyanidins (LPPC) from Larix gmelinii bark," BioRes. 9(1), 662-672.
A grading countercurrent extraction method was used to separate polymeric proanthocyanidins (LPPC) from degreased Larix gmelinii bark, and the purification of LPPC was performed using HP-2MGL resin. The purity of LPPC was 26.37%. The cumulative recovery rate of purified product (LPPC-1) was 98.54% by the adsorption method of HP-2MGL resin. The purity of LPPC-1 was 99.79%. Catalytic hydrogenolysis tests of LPPC-1 were performed by means of a palladium carbon catalyst. The degradation rate was 67.5%, and the residual rate was 72.1%. The results of antioxidant ability showed that the degradation product (LHOPC) had more excellent antioxidant ability compared with LPPC-1, VC, TBHQ, grape seed extract, and pine bark extract. The results, through the analysis of the linear model of MALDI-TOF/TOF MS, revealed that LHOPC was oligomeric with the tetramer as the major component and the distribution ranging from the trimer to eleven units. PDF
Nanocrystalline cellulose (NCC) was used to improve the anti-yellowing property of polyurethane (PU). The NCC was modified with 3-glycidoxypropyltrimethoxysilane (GPTMS) to enhance its compatibility with PU, and the surface-modified NCC was characterized by contact angle (CA), X-ray powder diffraction (XRD), and thermogravimetric analysis (TG). NCC/PU composite was examined by scanning electron microscopy (SEM), Fourier transform infrared spectrophotometer (FT-IR), and X-ray photoelectron spectroscopy (XPS). Anti-yellowing property of the NCC/PU composite was determined using the Chinese National Standard GB/T 23999-2009. The results showed that the CA between modified NCC and PU was decreased by 26.6% (with 8% GPTMS). The crystal structure of NCC was inconspicuously affected by the surface modification, while the thermal stability of modified NCC was enhanced by 5.5%. The surface-modified NCC particles were homogeneously dispersed in the PU (as shown in the SEM micrographs). FT-IR and O1s XPS survey spectra of NCC/PU composites indicated the oxidation of hydroxyl groups and the production of carbonyl groups, while the photochemical degradation of PU resulting from UV radiation was prevented by the addition of NCC. The anti-yellowing property of the NCC/PU composite with 1.5% surface-modified NCC was increased by 57.7% and the contribution was decreased when the content of modified NCC was 2.0%. PDF
Bian, R., Zhang, A., Li, L., Pan, G., Zheng, J., Zhang, X., Zheng, J., Joseph, S., and Chang, A. (2014). "Effect of municipal biowaste biochar on greenhouse gas emissions and metal bioaccumulation in a slightly acidic clay rice paddy," BioRes. 9(1), 685-703.
A field trial was performed to investigate the effect of municipal biowaste biochar (MBB) on rice and wheat growth, metal bioaccumulation, and greenhouse gas emissions in a rice paddy in eastern China. MBB was amended in 2010 before rice transplanting at rates of 0 and 40 t ha-1 in a field experiment lasting one cropping year. MBB soil amendment significantly increased soil pH, total soil organic carbon, and total nitrogen. The growth and grain yield of rice and wheat was not affected with MBB application at 40 t ha-1. MBB amendment did not influence the soil availability of Pb, Cu, and Ni, but significantly increased the soil availability of Zn and decreased the soil availability of Cd during both rice and wheat seasons. While MBB did not change the bioaccumulation of Pb, Cu, and Ni, the rice and wheat Cd accumulation was significantly reduced, and wheat Zn accumulation slightly increased with MBB amendment. Furthermore, total N2O emission during both rice and wheat seasons was greatly decreased, though total seasonal CH4 emission was significantly increased in the rice season. On the other hand, soil CO2 emission remained unaffected across crop seasons. Thus, MBB can be used in rice paddy for low carbon and low-Cd grain production, but the long-term effects remain unknown. PDF
In Korea, Pinus densiflora is one of the most important indigenous tree species in terms of making high-value wood products. Therefore, Korean sawmills exercise extreme caution to prevent fungal discoloration such as that caused by sapstains and molds on the timber. In this study, the effectiveness of using natural crude wood vinegar to inhibit sapstains and molds, especially on Pinus densiflora (Japanese red pine) was examined. Pinus densiflora wood samples were dipped in absolute and diluted wood vinegar at different concentrations (1:1, 2:1, and 3:1; deionized water to wood vinegar dilution ratio) for 3 minutes and immediately air-dried. In addition, volatile wood vinegar was also used in this study to imitate the condition of wood vinegar when exposed to open air. The degree of discoloration was examined and evaluated every 2, 4, 6, and 8 weeks according to the ASTM D4445-91 Standard Method for laboratory test. Crude wood vinegar inhibited sapstains more efficiently than it inhibited molds. Wood vinegar at a 1:1 concentration was found to be the most optimum treatment for inhibiting sapstains for at least 8 weeks. PDF
The processes of banknote deterioration in circulation and the factors causing this wear have been analyzed to determine the main factors in the process of banknote deterioration in real life circulation and to ascertain which of these factors could be simulated in the process of simulated circulation. The factors that should be taken into consideration during simulated circulation are systematic mechanical and chemical influences on a banknote. The developed Circulation Simulator Method was used to evaluate Ukrainian hryvnia banknotes to obtain artificially deteriorated banknote samples whose optical properties, weight change, air permeability, bursting strength, and stiffness were within the range of corresponding parameter changes for bank notes in actual circulation. The designed method consisted of multiple mechanical damages to tested banknotes by means of centrifugally rotating them within a closed container containing a wearing agent in the presence of a soiling mixture, which imitates the typical composition of soil in banknote circulation within Eastern Europe. The proposed method can be used to determine the durability of materials and to develop manufacturing processes for banknote production. PDF
Many pulp mills and biorefineries today are focusing on the utilization of their residual lignin for economic return. Although lignin can be burned to produce energy, it also has the potential for the production of value-added products. Technical lignins have modified structure and contain different impurities, which depend on the original material, as well as the extraction process. Among the various techniques for lignin extraction, kraft and steam explosion processes are the most commonly used in the pulping and biorefinery industries, respectively. The objective of this work was to compare the thermal behavior of industrial lignins produced from kraft pulping and steam explosion, with that of their chemically extracted, purified forms. It was found that the purified lignins have very similar thermal properties to one another, while impurities in the industrial lignins significantly alter their thermal behavior, and hence their potential in value-added applications. The percentage of degradation from 200 to 600 °C and glass transition temperature of original steam-exploded lignin was 68.5% and 149.16 °C, while of original kraft lignin was 26.0% and 109.82 °C. These values were altered after purification to 61.0% and 158.99 °C for steam-exploded lignin; and to 40.0% and 129.82 °C for kraft lignin, respectively. PDF
Espinach, F. X., Julián, F., Alcalà, M., Tresserras, J., and Mutjé, P. (2014). "High stiffness performance alpha-grass pulp fiber reinforced thermoplastic starch-based fully biodegradable composites," BioRes. 9(1), 738-755.
Alpha-grass was studied as the reinforcement in a starch-based polymer matrix. Mater-bi®-Y was chosen as a matrix due to its Young’s modulus, in line with that of polypropylene. The test specimens were injection molded and tensile tested. The obtained results were compared to glass fiber reinforced polypropylene. The reinforcing fibers increased the Young’s modulus significantly, obtaining values up to 7.2 GPa, comparable to those obtained with reinforced polypropylene. The contribution of the fibers to the final composite Young’s modulus was also studied, and it was found that was in line with other natural fibers contribution to polypropylene-based composites. Finally, it was found that the value of the efficiency factor of the module remained similar to that of natural fiber reinforced polypropylene. PDF
Cellulose/collagen composite films with weight ratios of 30/1 (Blend-1) and 10/1 (Blend-2) were prepared using 1-ethyl-3-methylimidazolium acetate as a common solvent. The morphology of the films observed with a field-emission scanning electron microscope displayed a dependence on the ratio of cellulose/collagen. Collagen was successfully composited with cellulose without degradation and showed a denaturation temperature (Td) higher than that of native collagen. Fourier transform infrared spectroscopy suggested that there were hydrogen-bong interactions between collagen and cellulose in the regenerated composite films. Thermogravimetric analysis revealed that the maximum decomposition temperature (Tmax) of cellulose decreased after regeneration, while the Tmax of Blend-1 increased; however, it was reduced again for Blend-2. Elastic moduli from dynamic mechanical analysis exhibited a trend similar to that of Tmax. As indicated by X-ray diffraction, the distance between cellulose molecular chains was shortened for Blend-1 and elongated for Blend-2. Furthermore, the crystallization indices were calculated to be 75.3%, 68.3%, 66.2%, and 55.4% for native cellulose, regenerated films of cellulose, Blend-1, and Blend-2, respectively. These results confirm the dependence of the structural properties of composite films on cellulose/collagen ratios through the interactions between cellulose and collagen. PDF
Furfural residue (FR), composed mainly of cellulose and lignin, is an industrial waste produced during furfural manufacture. In this study, dioxane, alkali, ethanol, alkali-ethanol, and alkaline hydrogen peroxide (AHP) were used to extract lignins from FR. The structural features of these lignins obtained were characterized by sugar analysis, GPC, UV, FT-IR, and HSQC spectra. As compared to dioxane lignin (DL), other lignins showed lower molecular weights (Mw) owing to the partial cleavage of the linkages between lignin units. Results from HSQC spectra revealed that β-O-4' and β-5' were still the major linkages of the FR lignin. Moreover, p-coumaric and ferulic acids were released and co-precipitated in the lignin preparations extracted with alkali and AHP, whereas part of the esters in DL were preserved during the dioxane extraction. Antioxidant activity investigation indicated that the antioxidant property of the alkali and alkali-ethanol lignins was higher than that of the commercial antioxidant, butylated hydroxytoluene. PDF
Cobreros, C., Espinosa, D., Hidalgo, F., Manzano-Ramírez, A., and Reyes, J. L. (2014). "Cereal straw production analysis, availability of materials, and provincial map for manufacturing of sustainable prefabricated panels," BioRes. 9(1), 786-800.
Throughout history, energy consumption and the demand for resources have gradually increased. The construction industry, by direct or indirect actions, consumes over 50% of the energy produced, is responsible for 30% of the CO2 emissions, and consumes more raw material than any other industrial activity. Architecture alone cannot solve global environmental problems, but it can contribute significantly. A high recyclability rate can be achieved through the management of renewable natural materials or waste. The application of prefabricated building systems can be an economical solution, saving energy and reducing waste. This work presents the prefabricated compressed straw panel as part of a paradigm shift toward sustainable architecture, which offers the opportunity to use new materials and construction systems but takes local and specific circumstances into account. The density of cereal straw for use in prefabricated compressed straw panel production in Badajoz, Spain was also studied. PDF
Villegas, M. S., Monteoliva, S. E., Achinelli, F. G., Felissia, F., and Area, M. C. (2014). "Effects of weed control and fertilization on wood and chemi-mechanical pulp properties of a Populus deltoides clone," BioRes. 9(1), 801-815.
Weed control and fertilization usually lead to an increase in the growth rate of trees and, consequently, to a possible modification of the quality of the wood and its end products. The effect of weed control and fertilization practices were determined on tree growth parameters, wood density, fiber weight, fiber length, and chemical wood composition, as well as the chemi-mechanical pulp properties, for 8-year-old Populus deltoides `Delta Gold´ grown in Argentina. Four treatments belonging to a randomized complete block design trial were analysed: no weeding after planting (C), mechanical weed control (M), chemimechanical weed control (CHM), and fertilized + chemimechanical weed control (CHM-F). Soda-sulfite chemi-mechanical pulps were produced from said trees. Handsheets were prepared from the pulps, and their physical, mechanical, and optical properties were determined following international standards. Several wood and pulp properties were influenced by the studied silvicultural practices. In the context of this study, silvicultural treatments applied to Populus deltoides ‘Delta Gold’ (formerly ‘Stoneville 66’) trees can be applied to increase productivity (volume and fibrous output) without detrimental consequences to wood and pulp properties, except for a slight reduction in brightness. PDF
In this paper, a method for utilizing knot information from computed tomography (CT) scanning of Scots pine (Pinus sylvestris L.) logs was evaluated. A high speed industrial CT scanner is being developed, which will enable scanning of logs in sawmills at production speed. This development calls for the ability to optimize breakdown parameters in a quick manner because there are many decisions to be made and the timeframe for these production decisions is short. One of the important breakdown parameters is in which rotational position to saw a log. The presented method used CT data to create a two-dimensional projection of knot information from a log, in order to minimize the amount of data to analyze. The center of mass of the knot projection relative to the center of the sawing pattern was chosen as the rotational position of the log. The aim was to put large knots on the flat surfaces of the boards, as knots on edge surfaces have a more negative effect on board quality in the sorting rules used in this study. The method was tested by sawing simulation and was compared with the industrial praxis of sawing logs horns down. The results show an increase in board quality and value, albeit for a selected group of Scots pine logs. The method is very sensitive to positioning errors, but it has some potential if sawlog positioning accuracy is improved. PDF
Li, Q., He, Z., Krishnan, S., Lussier, C., Woloveck, M., Gao, Y., Jahan, M. S., and Ni, Y. (2014). "The effect of pulp pad dryness in determining brightness using non-standard fast drying methods," BioRes. 9(1), 828-835.
In integrated pulp and paper mills a rapid pulp brightness determination method is needed at the pulp mill for quality and process control. In this study, the effect of dryness on the brightness reading of pulp pads has been studied. The results showed that in comparison with that from the TAPPI standard test procedure, the brightness was significantly lower when the pulp pad dryness was lower than 50%, implying that at pulp mills, the pulp pads should be dried quickly to a dryness of about 50% or higher in order to give rapid, yet reproducible brightness results. For this purpose, a forced hot air dryer was designed to dry the pulp pads to 50 to 60% dryness in about 15 minutes. The pulp pads which were dried with the forced hot air dryer had similar brightness readings to those prepared and dried by following the TAPPI standard method. Alternatively, a microwave oven can be used for the same purpose, and the pulp pads can be dried to about 50% dryness in 2.5 minutes. PDF
Modified ammonium lignosulfonate (MAL) and polyethylenimine (PEI) were combined and used as a binder in the manufacture of a wood-based green composite. The effects of hot pressing temperature (150 ºC to 190 ºC), hot pressing time (3 min to 11 min), binder content (10 wt.% to 30 wt.%), and MAL/PEI weight ratio (1:1 to 1:9) on the physico-mechanical properties of the composites were investigated. The composites met the mechanical property requirements for furniture grade medium density fiberboard (MDF-FN REG) under the following parameters: hot pressing temperature of 170 ºC, hot pressing time of 7 min, binder content of 20 wt.%, and MAL/PEI weight ratio of 7:1. Under optimum processing, although the X-ray diffraction analysis showed that the addition of either unmodified ammonium lignosulfonate (UMAL) or MAL did not change the crystalline structure, this addition markedly improved the relative crystallinity of the composites in comparison to that of pure wood fiber. The DMA results indicated that the MAL/PEI composites had higher storage modulus and tanδ values than did the UMAL/PEI composites. Moreover, SEM analysis showed that the MAL/PEI composites had better bonding strength characteristics than did the UMAL/PEI composites. PDF
Hemmasi, A. H., Khademi-Eslam, H., Roohnia, M., Bazyar, B., and Yavari, A. (2014). "Elastic properties of oak wood finger joints with polyvinyl acetate and isocyanate adhesives," BioRes. 9(1), 849-860.
In this study, the elastic properties of 23 specimens of oak timber(Quercus castaneifolia), including the longitudinal modulus of elasticity (MOE), acoustic coefficient (K), and acoustic converting efficiency (ACE) in free vibration using the free-free beam method with different planes of vibration, i.e. tangential (LT) and radial (LR), were studied. These elastic parameters were examined in both sound wood and finger jointed timbers with two different lengths of fingers (5- and 10-mm finger lengths) and individually glued with two different types of adhesives (isocyanate and polyvinyl acetate). Comparing the elastic properties of solid beams with finger jointed beams of oak wood in both (LT) and (LR) planes, 10-mm finger joints with polyvinyl acetate adhesive did not cause any serious change to the studied elastic properties of the beams, while shorter finger length (5 mm) with isocyanate adhesive severely changed the acoustic properties; therefore, beams having longer finger lengths may have enhanced acoustical properties. PDF
Sasthiryar, S., Abdul Khalil, H. P. S., Bhat, A. H., Ahmad, Z. A., Islam, M. N., Zaidon, A., and Dungani, R. (2014). "Nanobioceramic composites: A study of mechanical, morphological, and thermal properties," BioRes. 9(1), 861-871.
The aim of this study was to explore the incorporation of biomass carbon nanofillers (CNF) into advanced ceramic. Biomass from bamboo, bagasse (remains of sugarcane after pressing), and oil palm ash was used as the predecessor for producing carbon black nanofillers. Furnace pyrolysis was carried out at 1000 °C and was followed by ball-mill processing to obtain carbon nanofillers in the range of 50 nm to 100 nm. CNFs were added to alumina in varying weight fractions and the resulting mixture was subjected to vacuum sintering at 1400 °C to produce nanobioceramic composites. The ceramic composites were characterized for mechanical, thermal, and morphological properties. A high-resolution Charge-coupled device (CCD) camera was used to study the fracture impact and the failure mechanism. An increase in the loading percentage of CNFs in the alumna decreased the specific gravity, vickers hardness (HV), and fracture toughness values of the composite materials. Furthermore, the thermal conductivity and the thermal stability of the ceramic composite increased as compared to the pristine alumina. PDF
Daud, Z., Mohd Hatta, M. Z., Mohd Kassim, A. S., Awang, H., and Mohd Aripin, A. (2014). "Exploring of agro waste (pineapple leaf, corn stalk, and napier grass) by chemical composition and morphological study," BioRes. 9(1), 872-880.
Malaysia is a country that is a rich source of agricultural waste material. Three different crops were studied here, including pineapple (Ananas comosus) leaf, corn (Zea mays) stalk, and Napier grass (Pennisetum purpureum). These crops are characterized as agricultural waste materials in Malaysia and have a high potential to be used as alternative fibers for the paper making industry. The objective of this work was to analyze the chemical composition of pineapple leaf, corn stalk, and Napier grass and to investigate the fiber morphology of these crops. The chemical components analyzed include the following: cellulose (Kurshner-Hoffner method), holocellulose (chlorination method), hemicellulose (chlorination method), ash content (TAPPI method T211-om-93), lignin content (TAPPI method T222-om-98), and soluble sodium hydroxide (TAPPI method T203-om-98). All handsheets morphologies were observed using scanning electron microscopy (SEM). Results indicated each crop has the potential for use as a fiber in paper making. SEM images indicated a condensed composition of the fiber structure. The observed chemical composition and morphology of these three crops indicate their suitability for use as fiber sources for the paper industry. PDF
The kinetics of unidirectional penetration of NaOH aqueous solution into rectangular samples of wood oriented parallel to a stern axis were studied. Scots pine (Pinus sylvestris), European larch (Larix decidua), blackthorn (Prunus spinosa), white willow (Salix alba), and horse-chestnut wood (Aesculus hippocastanum) were studied in this work. The time dependence of liquid incorporation was measured by the volumetric method as a change of total volume of coexisting liquid (NaOH/H2O) phase. The total thickness of the swollen surface layer d and mean value of the apparent diffusion coefficient of aqueous NaOH solution at 22 °C were determined. PDF
The objective of this study was to investigate some mechanical and physical properties of three-layer particleboards with the core layer made from various willow (Salix viminalis) and industrial pine wood particle mixtures. Increasing willow content slightly worsened the modulus of elasticity and modulus of rupture but improved internal bond, screw holding, water absorption, and thickness swelling. The effects of resin content in the core layer and the density of particleboards were also studied. Mechanical properties, especially modulus of elasticity and internal bond, of particleboards with willow particles met the requirements of EN 312 standard for boards of type P2. The willow (Salix viminalis) can be considered as a substitute for pine wood for the manufacturing of the core layer of three-layer particleboards. PDF
Heikkinen, S. L., Mikkonen, K. S., Koivisto, P., Heikkilä, M. I., Pirkkalainen, K., Liljeström, V., Serimaa, R., and Tenkanen, M. (2014). "Long-term physical stability of plasticized hemicellulose films," BioRes. 9(1), 906-921.
Oat spelt arabinoxylan (OsAX) and spruce galactoglucomannan (GGM) are hemicelluloses that can be extracted in large quantities from side-streams of the agriculture and forest industries. They both form self-standing films, making them potential future packaging materials. This systematic study focuses on the effect of long-term storage on the physical stability of hemicellulose-based films. OsAX and GGM films were plasticized with 40% (w/w of the polysaccharide) of glycerol, sorbitol, or their blends, and their stability was followed for four months. Ageing especially affected the glycerol-containing films, in which the tensile strength and Young’s modulus increased and elongation at break decreased. Although the mechanical properties were altered, storage did not affect crystallinity of the films. Oxygen gas permeability (OP) and water vapor permeability (WVP) properties were monitored in OsAX films. Interestingly WVP decreased during storage; more than a 40% decrease was seen when plasticizer blends contained 50% or more glycerol. In contrast, there were no drastic changes in the OP during storage; all the OPs obtained were between 3.7 and 8.9 [cm3 µm/ (m2 d kPa)]. PDF
Characterizing the variance of material properties of natural fibers is of growing concern due to a wide range of new engineering applications when utilizing these natural fibers. The aim of this study was to evaluate the variance of the Young’s modulus of sunflower bark by (i) determining its statistical probability distribution, (ii) investigating its relationship with relative humidity, and (iii) characterizing its relationship with the specimen extraction location. To this end, specimens were extracted at three different locations along the stems. They were also preconditioned in three different relative humidity environments. The c2-test was used for hypothesis testing with normal, Weibull, and log-normal distributions. Results show that the Young’s modulus follows a normal distribution. Two-sample t-test results reveal that the Young’s modulus of sunflower stem bark strongly depends on the conditioning’s relative humidity and the specimen’s extraction location; it significantly decreased as the relative humidity increased and significantly increased from the bottom to the top of the stem. The correlation coefficients between the Young’s modulus of different relative humidity values and of specimen extraction locations were determined. The calculation of correlation coefficients shows a linear relation between the Young's modulus and the relative humidity for a given location. PDF
Investigating the mechanical behaviour of silica bodies in oil palm empty fruit bunches (OPEFB) is important to improve the process of silica body removal. This study will assist in providing an understanding of the role of OPEFB as a bioresource material for the bioconversion process. The microstructure of silica bodies/protrusions on the OPEFB fibre surface was modelled using the finite element method, based on the information obtained from scanning electron microscopy (SEM). The effects of silica body geometry, possible anisotropy/orthotropy, and debonding between the interface of the silica body and OPEFB fibre were investigated. Agreements were observed between the results using both circular and spiked silica body models with different geometries and volume fractions. In addition, the cohesive debonding modelling results showed that once critical stress was activated, the stress-strain curve deviated from the no-debond model. The results also suggested that the value of cohesive energy should be between 0.5 kN/m and 4 kN/m. PDF
Sim, S. F., Lee, T. Z. E., Mohd Irwan Lu, N. A. L., and Murtedza, M. (2014). "Modified coconut copra residues as a low cost biosorbent for adsorption of humic substances from peat swamp runoff," BioRes. 9(1), 952-968.
The presence of dissolved organic matter, scientifically known as humic substances, gives an undesirable color and taste to water. In addition, they are the precursors of carcinogenic disinfection by-products upon disinfection treatment. Adsorption provides a potential means of removal of humic substances, and lignocellulosic biomass serves as a promising candidate. In this paper, we report the application of modified coconut copra residues for adsorption of humic substances from peat swamp runoff. The FTIR spectra suggest that coconut copra residues are genuinely rich with carboxyl groups with long alkyl chains; this renders the material a natural biosorbent, attaining an average of 50% removal under the conditions of testing. Upon treatment, dissolution of lignin and hemicellulose with the enhancement of effective carboxyl groups occurs, improving the adsorption efficiency to 96%; the treated water is visibly clear. The relative band abundance and band shifts further confirm the involvement of the surface functional groups in the adsorption process. The modified coconut copra residue is an attractive biosorbent option for removal of humic substances. The operating conditions are mild, involving non-toxic chemicals, and no pH adjustment is necessary to allow adsorption. PDF
Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, the phenol adsorption of the ACs with melamine and urea modifications were 219.09 mg/g and 214.45 mg/g, respectively. Both were greater than the capacity of unmodified AC, which was 163.82 mg/g. The Langmuir isotherm adsorption equation well described the experimental adsorption isotherms. The adsorption kinetics was well explained by pseudo-second-order kinetics rather than the pseudo-first-order. In conclusion, the nitrogen-enriched activated carbon proposed as adsorbents of the phenol wastewater were shown to be effective, which also means that bamboo residues have promise as activated carbon precursors for liquid phase adsorbents for environmental protection. PDF
Formaldehyde-free tannin-based furanic foams were prepared by applying infrared radiation (IR) as an alternative energy source. Up to now, tannin-based rigid foams have been produced via heat conduction or microwave radiation energy. The present innovative heating system allows for the production of extra-light products with low density (≤ 50 kg/m³). The IR-produced lightweight tannin foams (IR-TF) exhibited similar properties to those made by hot pressing (HP-TF), but IR-TF can be synthesized with much shorter production time. Although microwave-produced foams (MW-TF) can be obtained with even shorter production times, the IR-TFs are much more homogeneous. Therefore, the IR radiation-based process resulted in the most suitable compromise between foam properties and production time. Overall, IR-TF showed very competitive structural characteristics, such as high homogeneity, high porosity, and limited orthotropicity, which was similar to that shown by the hot press-produced foams. The mechanical properties and material costs are rather similar, but the production time for IR-TF is considerably shorter. PDF
Xu, Q. H., Li, W. G., Cheng, Z. L., Yang, G., and Qin, M. H. (2014). "TEMPO/NaBr/NaClO-mediated surface oxidation of nanocrystalline cellulose and its microparticulate retention system with cationic polyacrylamide," BioRes. 9(1), 994-1006.
TEMPO/NaBr/NaClO-mediated surface oxidation of NCC, acid-extracted from aspen kraft pulp, was studied, and the properties of nanocellulose whiskers before and after oxidation were characterized by conductimetry, Fourier transform infrared spectroscopy, X-ray diffraction, and atomic force microscopy. The resulting products with varied oxidation degrees were then applied in the deinked pulp to evaluate the improvements of fines retention and pulp drainage. It was found that TEMPO-oxidized NCC maintained its crystalline form of cellulose I, while it showed better dispersibility and smaller dimension due to the high level of carboxyl content and degree of oxidation. By adding NCC and TONCC to the deinked pulp, the retention was improved while the drainage rate was decreased to some extent. When TONCC samples were applied together with cationic polyacrylamide to constitute a microparticulate retention system, both fines retention and pulp drainage were apparently improved. Further study showed that the retention and drainage rate were significantly influenced by the degree of oxidation. TONCC sample with the highest DO (0.134) gave the highest retention and drainage rate, 89.6% and 9.41 mL/s, respectively. PDF
Jenol, M. A., Ibrahim, M. F., Lai Yee, P., Salleh, M. M., and Abd-Aziz, S. (2014). "Sago biomass as a sustainable source for biohydrogen production by Clostridium butyricum A1," BioRes. 9(1), 1007-1026.
Biohydrogen production from biomass is attracting many researchers in developing a renewable, clean and environmental friendly biofuel. The biohydrogen producer, Clostridium butyricum A1, was successfully isolated from landfill soil. This strain produced a biohydrogen yield of 1.90 mol H2/mol glucose with productivity of 170 mL/L/h using pure glucose as substrate. The highest cumulative biohydrogen collected after 24 h of fermentation was 2468 mL/L-medium. Biohydrogen fermentation using sago hampas hydrolysate produced higher biohydrogen yield (2.65 mol H2/mol glucose) than sago pith residue (SPR) hydrolysate that produced 2.23 mol H2/mol glucose. A higher biohydrogen productivity of 1757 mL/L/h was obtained when using sago hampas hydrolysate compared to when using pure glucose that has the productivity of 170 mL/L/h. A comparable biohydrogen production was also obtained by C. butyricum A1 when compared to C. butyricum EB6 that produced a biohydrogen yield of 2.50 mol H2/mol glucose using sago hampas hydrolysate as substrate. This study shows that the new isolate C. butyricum A1 together with the use of sago biomass as substrate is a promising technology for future biohydrogen production. PDF
This research project deals with PVAc adhesives, their properties, and conditions of use. The primary objective of this study is to verify the dependence of the strength increase in a bonded joint on the curing time. The bonding process used the following PVAc adhesives: Kleiberit 303, Propellerleim 3W, 4B Plus, and Provotil, conforming to resistance classes D3 and D4 pursuant to ČSN EN 204. The test objects and processing of results were in accordance with ČSN EN 205. The readings were converted into charts demonstrating the strength increase in the bonded joints. The strength required in these adhesives by the standard is 10 MPa, and it is prescribed that the test should be performed over the 7 days following the assembly bonding (ČSN EN 204). The tested adhesives achieved this value in a time period of 75 min to 165 min, depending on the adhesive type. It also follows from the measurement that the results differ depending on the sort of adhesive. Comparison of the results with those of other authors (Košíček 1974; Eisner 1966; Eisner et al. 1983; Sedliačik 2005) indicates that the strength increase pattern is not changed with product development and that the differences are due to adhesive modifications by the manufacturers. PDF
Bylin, S., Olsson, C., Westman, G., and Theliander, H. (2014). "Solvation behavior of cellulose and xylan in the MIM/EMIMAc ionic liquid solvent system: Parameters for small-scale solvation," BioRes. 9(1), 1038-1054.
Ionic liquid treatment has been reported by several researchers as a possible step in the process of fractionating lignocellulosic biomass within the biorefinery concept. However, understanding how solvation can be achieved and how the feedstock biopolymers are affected is needed prior to a viable implementation. An effective two-component solvent system for the wood components cellulose and xylan has been developed. Furthermore, the solvation of these components in the system consisting of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate (EMIMAc) in a novel combination with the co-solvent 1-methylimidazole (MIM) is investigated. Focused beam reflectance measurement (FBRM) particle characterization in combination with microscopic analysis and molecular weight determinations (xylan) shows that cellulose and xylan can be most efficiently solvated using only 3 to 4% IL (n/n anhydro-glucose units and n/n anhydro-xylose units) and 9% IL, respectively, while still avoiding any significant polymer degradation. A model for a two-step process of cellulose solvation in the present system is proposed. PDF
Sun, Y.-C., Lin, Z., Peng, W.-X., Yuan, T.-Q., Xu, F., Wu, Y.-Q., Yang, J., Wang, Y.-S., and Sun, R.-C. (2014). "Chemical changes of raw materials and manufactured binderless boards during hot pressing: Lignin isolation and characterization," BioRes. 9(1), 1055-1071.
Thermomechanical pulp (TMP) is used for fiber production in binderless boards industries. Milled wood lignin (MWL) and enzymatic mild acidolysis lignin (EMAL) isolated from raw material and from binderless boards (BB) were comparatively analyzed to investigate the effects of chemical changes on the bonding performance in BB. The results showed that acid-insoluble lignin of the BB were increased during the sodium silicate solution pretreatment after hot-pressing. The lignin fractions obtained were characterized by gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, and 1H-13C correlation heteronuclear single-quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscop y. Results showed that 31.1% of EMAL (based on Klason lignin) with low molecular weight (Mw=1630 g/mol) was isolated from the BB. The increased total phenolic OH groups (3.97 mmol/g) of EMAL from sodium silicate solution pretreated BB indicated that there was degradation of lignin and cleavage of lignin-carbohydrate linkages during hot-pressing. In addition, the content of β-O-4' aryl ether linkages of EMAL from the BB increased to 69.2%, which was higher than that of the untreated sample (60.1%). It was found that S units (syringyl-like lignin structures) were preferentially condensed by hot pressing over G (guaiacyl-like lignin structures) units, and the S/G ratio increased after the hot-pressing process. PDF
Lee, K. C., Arai, T., Ibrahim, D., Kosugi, A., Prawitwong, P., Lan, D., Murata, Y., and Mori, Y. (2014). "Purification and characterization of a thermostable laminarinase from Penicillium rolfsii c3-2(1) IBRL," BioRes. 9(1), 1072-1084.
A laminarinase (endo-β-1,3-glucanase) was purified to homogeneity from Penicillium rolfsii c3-2(1) IBRL, which was originally produced in liquid culture containing 1% xylan from birchwood, via anion-exchange chromatography, gel filtration on Sephacryl S-100, and hydrophobic interaction chromatography. A single protein band with a molecular weight of 75 kDa was detected by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which had an optimum catalytic activity at pH 4.0 to 5.0 and 70 °C. This purified enzyme was most stable in the pH range 4 to 7, while it was thermostable up to 55 °C and retained up to 90% of its activity after 4 h pre-incubation. A substrate laminarin kinetic study yielded estimated Km and Vmax values of 0.0817 mg/mL and 372.2 µmol/min/mg, respectively. Laminari-oligosaccharide degradation, which was analyzed by thin layer chromatography, yielded the major hydrolysis products laminaribiose and glucose. PDF
Yang, F., Fei, B., Wu, Z., Peng, L., and Yu, Y. (2014). "Selected properties of corrugated particleboards made from bamboo waste (Phyllostachys edulis) laminated with medium-density fiberboard panels," BioRes. 9(1), 1085-1096.
A simple, practical, and low-technology approach was developed to fabricate corrugated bamboo particleboards (CBP), a novel bamboo product with a corrugated structure, from bamboo waste (planer waste). This product could be manufactured anywhere in the world where the bamboo industry develops. The selected mechanical and physical properties of CBP were prepared with urea formaldehyde resin at three press temperatures and two density levels and were evaluated. The results showed that the performance of CBPs is highly dependent upon the board density. The static bending strength of CBP laminated with MDF initially increases, and then decreases with increasing press temperature. Increasing the magnitude of the press temperature has a slightly positive effect on the thickness swelling and water absorption. Compared with the excellent mechanical strength of CBP (laminated with MDF), the thickness swelling value of this bamboo-based particleboard without any waterproofing treatment was lower than the minimal requirement of the EN standard. PDF
Uniaxial compression tests in the grain (longitudinal) direction of solid wood were conducted using specimens of Sitka spruce and Japanese birch. The nonlinear stress-strain behavior was analyzed using plasticity theory, which is typically applied to ductile materials such as metals. The relationship between the longitudinal and tangential directions obtained from the experimental results showed nonlinearity, as predicted based on plasticity theory. Nevertheless, it was more pronounced in the experimental results than in the plasticity analysis. PDF
A new net-cationic polyacrylamide dry strength agent was synthesized through free radical polymerization using acrylamide (AM), itaconic acid (IA), N,N-dimethylacrylamide (F), and sodium methallyl sulfonate (T). Ethylene diamine tetraacetic acid was used as a chelating agent; dimethylaminoethyl methacrylate methyl chloride (DMC) solution was used as a cationic monomer, and ammonium persulfate (APS) was used as an initiator. Orthogonal design and single-factor experiments were utilized to study the effect of many factors, such as reaction time, the ratio of monomers, and the dosage of APS and DMC on the cationic polyacrylamide. The synthesized products were characterized by Fourier transform infrared spectroscopy (FTIR), gel permeation chromatography (GPC), particle charge detector (PCD), and zeta potential analysis. The results showed that the optimum conditions were as follows: optimal monomer proportion: m(AM):m(IA):m(T):m(F) = 23.79:2.39:0.21:0.32; w (DMC) = 28%; w (APS) = 1.0%, reaction time was 3 hours, reaction temperature was 93 °C, stirring speed was 130 rpm, and reaction pH value was 3.0. The solid content of the polymer was 21.2%. By adding the cationic polyacrylamide to old corrugated container pulp, the tensile index increased by 29.7% and the burst index increased by 66.1%, displaying the obvious enhancement of the paper. PDF
Xiao, H., Zhao, G.-L., Li, J.-R., and He, B.-H. (2014). "Hydrophobically associating polyethylenimine for controlling dissolved and colloidal substances of alkaline peroxide mechanical pulp," BioRes. 9(1), 1121-1131.
In a paper mill’s water circuit, normal runnability of the paper machine is often disturbed due to buildup of hydrophobic dissolved and colloidal substances (DCS), such as wood pitch, white pitch, and stickies. General cationic fixing agents such as hydrophilic polymers do not always work to minimize these problems. In the present study, two kinds of novel hydrophobically associating polyethylenimine (PEI) coagulants grafted by acetic anhydride and 1,2-epoxydodecane, named PEI-Ac and PEI-Ed, respectively, were synthesized to remove hydrophobic DCS. The performances of the modified PEI samples were evaluated using a model suspension containing alkaline peroxide mechanical pulp (APMP) and styrene-butadiene latex. The results showed that the modified PEI was more inclined to interact with hydrophobic substances than was non-modified PEI. The relationship between DCS removal and non-modified or modified PEI content was not linear, but there was a maximum. The turbidity and particle counts of model suspensions decreased 30% and 80%, respectively, when the dosage of PEI-Ed(a) was 0.025%. Compared with the 72.8% decrease in the case of non-modified PEI, cationic demand decreased by 67.7% when the PEI-Ed(a) concentration was 0.2%. It was also found that PEI-Ed had a better affinity for DCS than PEI-Ac, which may be because the PEI-Ed had a long hydrophobic chain. PDF
This article investigates the relationships between ring width (expressed as ring width class) and cambial age (expressed as chronological class) with specific gravity, modulus of rupture (MOR), compressive strength, and shrinkage. On those stands located on volcanic soils, it was found that when moving from the first ring width class (≤2 mm) to the seventh class (≥7 mm), a total decrease in specific gravity of 12.7% was observed, accompanied by a 19.5% decrease in compressive strength and a 22.8% decrease in MOR. With an increase in tree age, as expressed by the chronological class, there was a general decrease in the values of specific gravity, MOR, and compressive strength. It was therefore determined that chronological class is related to ring width, while specific gravity can predict MOR and compressive strength values for trees grown at volcanic sites. The results for a stand grown on calcareous soils showed a different trend. Furthermore, it was confirmed by cross-variance analysis that there was a correlation between ring width and chronological class. PDF
Styrene (SM), methyl methacrylate (MMA), and butyl acrylate (BA) were used to synthesize a polyacrylic emulsion by core-shell emulsion polymerization. The solid content of the emulsion reached 40% using reasonable reactive emulsifier contents and feeding modes. Then, the emulsion and a fiber were dispersed, coated, and dried together. Finally, fiber-based water-resistant material was successfully fabricated. The experimental results showed that under the conditions of a monomer mass ratio of 1:1:1 and a mass ratio of polyacrylic emulsion to fiber of 2:1, the Cobb value of the material reached 5.0 g/m2. The tensile strength, elongation, and breaking length were 7.4225 kN/m, 1.0%, and 11.706 km, respectively. Using scanning electron microscopy (SEM) to analyze the surface morphology and internal structure of products, the reasons for the high water resistance of fiber-based material was due to the bonding and filling effects of the polyacrylic emulsion on the fibers. For tightly bound fibers, the porous structures formed in fiber-based boards were reduced. On the other hand, the polyacrylic emulsion filled the gaps between fibers. This filling effect led to a continuous structure, and the water resistance of the material was further enhanced. PDF
Dimensional changes in bamboo strandboard could decrease the bond durability, causing problems for structural materials. Thus, it is critical and of practical importance to study the relationship between thickness swelling (TS) and internal bond (IB) strength loss on bamboo strandboard. To determine the relationship between dimensional stability and bond durability of bamboo strandboard, various densities and board types were examined. The results show that board density and board types affected TS and water absorption (WA). The board with lower density was easier to swell than that of higher density. The board density influenced the TS/WA ratio for short-term water soaking, but not for long-term water soaking. For layer-structured board, the TS/WA ratio of randomly oriented homogenous board (RAND board) was slightly higher than that of uni-directionally oriented homogenous (UNID), three-layered oriented strandboard with cross-oriented core layer (3LYC), and three-layered oriented with random core (3LYR) boards. The maximum swelling can only be reached by high-temperature water soaking. The IB strength loss of UNID board was higher than that of RAND board. PDF
This study considers ground wood fiber length distributions arising from pilot grindings. The empirical fiber length distributions appear to be independent of wood fiber length as well as feeding velocity. In terms of mathematics the fiber fragment distributions of ground wood pulp combine an exponential distribution for high-length fragments and a power-law distribution for smaller lengths. This implies that the fiber length distribution is influenced by the stone surface. A fragmentation-based model is presented that allows reproduction of the empirical results. PDF
Polyvinyl acetate (PVA) is commonly used to bond wood materials, but it generally exhibits poor performance when used in composites that require resistance to water and creep. However, it can be reinforced with different particles to improve its performance, making it useful for various applications. In this study, PVA was reinforced with cellulose fibers (CFs) at different loadings (1%, 2%, and 4%). A mixer was used to blend the PVA and CFs. Thermal properties and morphological structure of CF-reinforced PVA adhesive were studied by thermogravimetric analysis (TGA/DTG) and scanning electron microscopy (SEM). The lap joint shear strength of woods bonded by CF reinforced PVA adhesive was tested on poplar and Scots pine woods that had 12% moisture content. The addition of CFs to PVA increased the thermal stability of PVA to different extents depending on the degree of loading on the CFs. The results of morphological studies indicated that some fluctuations on the SEM pictures were observed due to the dispersion of the CFs in the PVA matrix. The results showed that lap joint shear strength of the two different species of wood increased in all states after CFs were added to the PVA. PDF
To modify water absorption properties of bamboo fiber (BF) and high density polyethylene (HDPE) composites, heat treatment of BFs was performed prior to compounding them with HDPE to form the composites. The moisture sorption property of the composites was measured and their diffusion coefficients (Dm) were evaluated using a one-dimensional diffusion model. Moisture diffusion coefficient values of all composites were in the range of 0.115x10-8 to 1.267x10-8 cm2/s. The values of Dm decreased with increasing BF heat-treatment temperature, and increased with increasing BF loading level. The Dm value of 40 wt% bamboo fiber/HDPE composites with BFs treated with 100 °C was the greatest (i.e., 1.267x10-8 cm2/s). Morphology analysis showed increased fiber-matrix interfacial bonding damage due to fiber swelling and shrinking from water uptaking and drying. The mechanism of water absorption of the composite, indicated a general Fickian diffusion process. PDF
Canola straw can be used as a raw material for the production of chemimechanical pulp (CMP). In this work, chemimechanical pulp was first produced from canola straw, and then the bleaching performance of the produced chemimechanical pulp was investigated under different conditions (dosages of NaOH and Na2SO3, time, and temperature). The results showed that the yield of chemical pretreatment in the CMP process varied between 57.6% and 64.9%, while the total yield of the process was between 54.1% and 61.9%. Subsequently, the CMP pulp produced via applying 4% NaOH and 8% Na2SO3 at 145 °C for 15 min was bleached with H2O2. The results showed that pulps bleached via applying one stage of 3% H2O2, 3% NaOH, 6% sodium silicate, 0.5% MgSO4, and 0.3% DTPA for 150 min possessed the highest brightness of 60.8% ISO, which is suitable for container board production. PDF
Wood energy is derived from a variety of wood-based sources, the most prominent of which is the fuelwood obtained directly from trees and forests. The genus Acacia includes over 1,000 species spread all over the world. Six indigenous acacia species that grow naturally in the southwest region of Saudi Arabia were selected in November 2010 from the Abha and Al-Baha forests to determine the heating values and chemical constituents of their wood on a comparative basis. The results showed that they differed significantly in their chemical components and heating value. The highest heating value (20.45 MJ kg-1) was found in the wood of A. tortilis, while A. ehrenbergiana had the lowest (18.00 MJ kg-1)—although the latter species is the most popular in the Kingdom for firewood. Trees grown in the Al-Baha region had greater heating values than those in the Abha region. The heating values were highly positively correlated with the contents of lignin (R2=0.70) and total extractives (R2=0.56). PDF
Sun, Y., Lanouette, R., Cloutier, J.-N., Pelletier, É., and Épiney, M. (2014). "Impact of selective refining combined with inter-stage ozone treatment on thermomechanical pulp," BioRes. 9(1), 1225-1235.
The aim of this study was to evaluate the performance of selective refining combined with ozone inter-stage treatment in a TMP process. A fractionation process was carried out to separate the primary pulp into two fractions, a long-fibre fraction and a short-fibre fraction. Different charges of ozone, namely 1%, 1.5%, and 2%, were used to treat the long-fibre fraction, and only the treated pulp went to the second refining stage. Finally, the secondary pulp was recombined with the primary short-fibre fraction to be compared to a control TMP trial. Results showed that 21% of the total refining energy can be saved when 1.5% ozone inter-stage treatment is applied before selective refining compared with whole pulp refining, when the pulp freeness is 100 mL. At this level of ozone charge, a slight increase in tensile strength is observed with no significant variation in tear index. PDF
Ozonation was used for tertiary treatment of hardwood KP bleaching effluent. The objectives were to investigate the performance of ozonation on reduction of recalcitrant COD and color in the biologically treated effluent and to investigate the change in biodegradability of the effluent during the ozonation process. The results indicate that COD removal was enhanced by increasing solution pH and temperature, but that the recalcitrant COD was not completely removed from the effluent due to ozone-resistant substances that remain in the effluent after ozonation treatment. Ozonation of the effluent was more effective for decoloration than for COD removal. The highest decoloration efficiency and COD reduction were 99% and 55% at pH 11.7 and 25 °C. It was observed that the biological oxygen demand (BOD5) and BOD/COD ratio were 93 mg/L and 0.40, after 30 min of ozonation, which was an increase of up to 102% and 185%, indicating enhanced biodegradability of the effluent after ozonation treatment. This obvious increase in biodegradability implies that the ozone-resistant substances can be decomposed by ozonation to produce compounds that are more biodegradable. PDF
Waste aspen sawdust was used as a precursor to prepare binderless active carbon monoliths (ACMs) with high porosities. The ACMs were prepared by activation with H3PO4 at different activation temperatures (500 to 700 °C) and retention times (1 to 3 h). Their morphologies, yields, textural properties, and microcrystalline structures were investigated using scanning electron microscopy (SEM), an analytical balance, N2 adsorption/desorption techniques, and X-ray diffraction (XRD). The results indicated that waste aspen sawdust could be successfully converted into highly porous binderless ACMs. The apparent specific surface area (SSA) and yield of ACMs were in the range of 688 to 951 m2/g and 26.6 to 36.2%, respectively. Highly microporous ACMs with a micropore percentage of 91.1%, apparent specific surface area of 951 m2/g, pore volume of 0.481 mL/g, and bulk density of 0.56 g/mL could be produced by activation at 700 °C for 1 h. Increasing the activation temperature or retention time increased the specific surface area, pore volume, and turbostratic degree, but decreased the yield. PDF
In this work, a surface sizing agent for paper was prepared by the emulsion polymerization method, in which the collagen extracted from leather shavings was modified. The product was characterized using Fourier Transform-Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), Energy Dispersive X-ray detector (EDX), and atomic absorption spectrophotometry. Corrugated papers were used as models. The synergy between modified collagen sizing emulsion and two commercial synthetic sizing agents was studied. Finally, the morphology of the papers before and after being treated was observed by Scanning Electron Microscopy (SEM). The results indicated that the sizing agent could be prepared using collagen as a raw material, which not only can alleviate a pollution problem in the leather industry, but also provide a novel alternative sizing agent for the paper industry, providing considerable economic, social, and environmental benefits to both industries. PDF
The synthesis of a macro-initiator from cellulose in mixtures of zinc-based ionic liquid and polar solvents including deep eutectic solvent, dimethylformamide, acetone, and tetrahydrofuran (THF) was studied. The results of FTIR and NMR spectroscopies indicated that the cellulose-based macro-initiator can only be obtained in an inert ether solvent, THF. When the amounts of cellulose and zinc-based ionic liquid were fixed at 0.5 g and 18 mL, respectively, the degree of substitution of the cellulose-based macro-initiator obtained was increased from 11.0% to 17.4% as the reaction temperature was increased from room temperature to 40 °C, as calculated from TGA thermograms. When the amount of cellulose was cut in half, a degree of substitution of 27.5% was achieved due to lower viscosity and better homogeneity of the reaction medium. A green, new, and relatively cheap approach has been shown to be suitable for synthesizing a cellulose-based macro-initiator. PDF
Understanding the structural features of lignin (L) and lignin-carbohydrate complexes (LCC) in bamboo (Phyllostachys pubescens Mazel) is important in order to expand the use of bamboo biomass. In this study, L and LCC were isolated from four-year-old mature bamboo using an organic solvent as an extractant. The structural features of L and LCC were characterized via UV-vis, FT-IR, NMR, sugar composition analysis, and alkaline nitrobenzene oxidation. L and LCC contained almost the same structural units: guaiacyl (G), syringyl (S), p-hydroxybenzoate substructures (PB),β-O-4’ substructures (A), 3-O-acetyl-(1→4)-linked- β-d-xylopyranosyl (βXyl3), (1→4)-linked-α(β)-d-xylopyranosyl (α(β)Xyl), and 4-O-methyl-α-d-glucuronic acid (MeGlcA(1→4)). The contents of the units varied between L and LCC. Carbohydrates linked with lignin in L and LCC mainly consisted of xylans. The sugar units of carbohydrates linked with lignin in LCC were determined to be of xylose (76.98%), arabinose (4.08%), glucose (6.47%), mannose (6.34%), altrose (3.69%), galactose (1.75%), and ribose (0.69%). The S (75.80%) and G (24.20%) units with a high S/G ratio of 3.13 were the main structural elements of lignin associated with carbohydrates in LCC. PDF
Fang, Z.-F., Liu, K. L., Chen, F.-S., Zhang, L.-F., and Guo, Z. (2014). "Cationic surfactant-assisted microwave-NaOH pretreatment for enhancing enzymatic hydrolysis and fermentable sugar yield from peanut shells," BioRes. 9(1), 1290-1302.
Production of bioethanol from lignocellulosic biomass is difficult due to differences in the feedstock. There is a need for an efficient pretreatment method that not only reduces the total process economy but also increases the total process efficiency. Following microwave-NaOH pretreatment of peanut shells in the presence of the cationic ionic surfactant cetyltrimethylammonium bromide (CTAB) and enzymatic hydrolysis, the pretreatment efficiency was significantly enhanced. The structural changes before and after pretreatment were detected by Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). FTIR and SEM showed the differences between the untreated and pretreated samples. The XRD profile showed that the degree of crystallinity was higher for pretreated materials than for untreated ones. These changes also verified the effect of CTAB during pretreatment of peanut shells. PDF
Di Pasqua, R., Ventorino, V., Aliberti, A., Robertiello, A., Faraco, V., Viscardi, S., Pepe, O. (2014). "Influence of different lignocellulose sources on endo-1,4-β-glucanase gene expression and enzymatic activity of Bacillus amyloliquefaciens B31C," BioRes. 9(1), 1303-1310.
Conversion of cellulose into fermentable sugars for ethanol production is currently performed by enzymatic hydrolysis catalyzed by cellulases. The cellulases are produced by a wide variety of microorganisms, playing a major role in the recycling of biomass. The endo-1,4-β-glucanase (CelB31C) from Bacillus amyloliquefaciens B31C, isolated from compost and previously selected on the basis of highest cellulase activity levels among Bacillus isolated, was characterized as being a potential candidate for a biocatalyst in lignocellulose conversion for second-generation bioethanol production. The aim of this work was to evaluate the changes in production of enzymatic activity of the endo-1,4-β-glucanase (CelB31C) and the expression of its gene (bglC) using a carboxymethylcellulase activity assay and qRT-PCR analysis, respectively, during growth of B. amyloliquefaciens B31C on different cellulose sources: carboxymethylcellulose (CMC), pure cellulose from Arundo donax, pretreated Arundo donax biomass (Chemtex), and microcrystalline cellulose (Avicel). The results showed that both the expression of bglC gene and the enzymatic activity production are related to the type of cellulose source. The strain showed a high enzymatic activity on lignocellulosic biomass and on microcrystalline cellulose. Furthermore, the highest gene expression occurred during the exponential phase of growth, except in the presence of Avicel. PDF
To evaluate the biofuel potential of bagasse, an abundant co-product in sugarcane-based industries, the effect of steam explosion on the efficiency of enzymatic saccharification and anaerobic digestion was studied. Bagasse was steam exploded at four different severity levels, and the impact of pretreatment was evaluated by analyzing the release of glucose after enzymatic saccharification with Cellic CTec2 and by analyzing methane production during anaerobic batch digestions. Increasing the severity of pretreatment led to degradation of xylan and the formation of pseudo-lignin. The severity of pretreatment was correlated with the enzymatic release of glucose; at optimal conditions, > 90% of the glucan was released. The highest methane yield (216 mL/gVS) was 1.3 times higher than the yield from untreated bagasse. More importantly, the pretreatment dramatically increased the rate of methane production; after 10 days, methane production from pretreated material was approximately twice that of the untreated material. To assess the possibility of developing combined processes, steam-exploded bagasse was enzymatically pre-hydrolyzed and, after the removal of released sugars, the remaining solid was subjected to anaerobic digestion. The results indicated that, in terms of total heating value, combined ethanol and biogas production is as beneficial as producing only biogas. PDF
Five steroidal sapogenins (tigogenin, neotigogenina, hecogenin, gloriogenin, and dehydrohecogenin) were characterised by gas chromatography coupled with mass spectrometry (GC-MS) from a hydrolysed extract of sisal waste. In addition, pure hecogenin, an important raw material for the pharmaceutical industry, was obtained from this waste by selective liquid-liquid extraction of saponins with only hecogenin as aglycone, followed by acid hydrolysis. The yield of pure hecogenin was 460 mg.Kg-1 of sisal waste. PDF
In the process of acid hydrolysis of cellulose, hydrolyzing the amorphous regions while retaining the crystalline regions is the key technology for obtaining microcrystalline cellulose products. This paper investigated the influence of FeCl3 on selective acid hydrolysis of crystalline regions and amorphous regions of cellulose. X-ray diffraction data indicated that FeCl3 can enhance the selectivity of acid hydrolysis for amorphous regions of cellulose, thus improving the crystallinity of hydrocellulose. Meanwhile, the crystalline structure did not change. Response surface methodology (RSM) was employed to optimize the crystallinity of hydrocellulose with respect to FeCl3 concentration, HCl concentration, reaction time, and temperature, and the relevant mathematical regression equation model was established. Under optimal conditions, the crystallinity of hydrocellulose was as high as 63.59% at 88.28 °C, 2.46 M HCl, 0.4 M FeCl3, and reaction duration of 64.02 min, which was in agreement with the predicted value. PDF
This paper deals with splinter size analysis of beech wood, considering the angular tool of the cutter and also the physical and mechanical wood properties substantially influencing wood processing technology. Particle size analysis was conducted by sieving the samples using a set of laboratory sieves, with subsequent determination of the individual fraction shares. The results have been compared with respect to the possibility of wood waste separation and filtration, and its subsequent utilization, above all, in the production of agglomerated materials and production of wood briquettes and pellets. The most frequently occurring fractions in native beech samples range between 5 and 8 mm and between 2 and 5 mm, while powder fractions below 125 μm were found in less than 1% of investigated samples. The most frequently occurring fractions in thermally modified beech wood ranged from 0.5 to 1 mm, and the share of powder wood particles below 125 μm was less than 4%. PDF
Precipitated calcium carbonate (PCC) is a filler that is widely used for papermaking, and lime sludge is a special type of PCC recovered from the black liquor from kraft pulping. There has been some concern that lime sludge may interfere with the development of paper’s hydrophobicity in comparison with commercial PCC and ground calcium carbonate (GCC) due to the presence of impurities when alkyl ketene dimer (AKD) is used as the sizing additive. In this work, fillers with different particle size distributions were prepared, and the effects of particle composition on surface chemistry of fillers, adsorption for AKD, sizing degree of final paper sheets, and retention behavior of fillers were evaluated. The results showed that, through matching different particle size distributions for lime sludge fillers, the negative zeta potential decreased from -26.2 mV to -20.8 mV, the specific surface area decreased from 15.0 m2/g to 9.1 m2/g, and total pore volume decreased from 0.037 cm3/g to 0.026 cm3/g, which was favorable for the low adsorption for AKD. Consequently the sizing effect of filled paper was improved. Moreover, the retention rate also was increased by changing the particle size distribution of lime sludge. PDF
The forest products industry has an opportunity to reduce energy costs using energy management practices, thereby boosting its global competitiveness. Increasing manufacturing costs have contributed significantly to the decline of the forest products manufacturing industries in the U.S.; these increasing costs limit manufacturers’ abilities to compete with their global competitors. U.S. companies are continually improving their products, processes, finances, and business practices to better compete with global marketplaces; however, they may not be seizing all of the opportunities available through more efficient energy consumption practices. By eliminating non-valued added activities, lean thinking is an example of one tool that may improve performance and reduce costs. A case study was conducted at a cabinet manufacturer in Virginia to examine the impact of lean thinking on the consumption of electricity in the manufacturing process. An energy management system was used to provide rapid feedback on electrical energy consumption for production operations. Significant changes were observed after implementing energy reduction practices identified by lean thinking tools. PDF
Frigerio, P., Zoia, L., Orlandi, M., Hanel, T., and Castellani, L. (2014). "Application of sulphur-free lignins as a filler for elastomers: Effect of hexamethylenetetramine treatment," BioRes. 9(1), 1387-1400.
Lignins from a steam explosion process in crude and purified forms and modified sulphur-free commercial lignin (Protobind 3000®) were characterised to establish their chemical compositions. Then, the lignins were tested again after treatment with hexamethylenetetramine (HMT). The resulting products were used to make rubber composites, and their mechanical properties were compared to rubber composites made with carbon black to test the possibility of using HMT-treated lignins as a partial replacement for carbon black in the production of rubber composites. In the crude lignin, a significant amount of impurities were detected, such as ash and residual polysaccharides, and these substances interfered in filler-elastomer interactions. The purified lignin maintained a high content of strongly polarised hydroxyl groups that interfered with the interaction of the filler and elastomer, resulting in low performance. Improvements in the mechanical properties were observed using Protobind 3000® lignin or purified lignin with HMT added during mixing with the rubber. Finally, the mixing of HMT-treated lignin with elastomers resulted in composites with higher reinforcement abilities compared to previously described rubber composites. However, in all samples, a poor and unsatisfactory dispersion of lignin in the polymeric matrix was observed. This is likely due to the incompatibility of lignin with the hydrophobic rubber, resulting in lower performances compared to the carbon black. PDF
Abdul Halip, J., Md. Tahir, P., Choo, A. C. Y., and Ashaari, Z. (2014). "Effect of kenaf parts on the performance of single-layer and three-layer particleboard made from kenaf and rubberwood," BioRes. 9(1), 1401-1416.
This study investigated the effect of kenaf parts (kenaf whole stem, kenaf core, and kenaf bast) on the mechanical and physical properties of single-layer and three-layer particleboards made from kenaf (Hibiscus cannabinus L.) and rubberwood (Hevea brasiliensis). The findings showed that the use of kenaf whole stem, which consists of both core and bast, had a positive effect on the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), permeability, thickness swelling (TS), and water absorption (WA) values of single-layer and three-layer panels. Single-layer admixture panels made from a combination of 70% rubberwood and 30% kenaf had greater strength and stability than single-layer homogeneous panels. The presence of rubberwood particles on surface layers significantly improved the elastic properties of three-layer panels. Panels with kenaf whole stem in the middle layer had better performance than panels with kenaf core. The MOE values of 35RW-30KWS-35RW panels were 56% and 79%, which were higher than those comprising single layers of 100% KWS and 100% KC, respectively. This study suggests that kenaf whole stem is the preferred material to be used in particleboard manufacture incorporated with rubberwood as an admixture for three-layer panels. PDF
This article deals with the influence of some cutting parameters (geometry of cutting edge, wood species, and circular saw type) and cutting conditions on the wood crosscutting process carried out with circular saws. The establishment of torque values and feeding power for the crosswise wood cutting process has significant implications for designers of crosscutting lines. The conditions of the experiments are similar to the working conditions of real machines, and the results of individual experiments can be compared with the results obtained via similar experimental workstations. Knowledge of the wood crosscutting process, as well as the choice of suitable cutting conditions and tools could decrease wood production costs and save energy. Changing circular saw type was found to have the biggest influence on cutting power of all factors tested. PDF
Liu, J., Ju, M., Wu, W., Liu, B., Zhan, L., Wu, M., Wang, P., Liu, Y., and Tong, S. (2014). "Lignocellulolytic enzyme production in solid-state fermentation of corn stalk with ammoniation pretreatment by Lentinus edodes L-8," BioRes. 9(1), 1430-1444.
This study investigated the effect of ammoniation pretreatment of corn stalk (CS) with different temperatures, ammonia proportions, and processing times on lignocellulolytic enzyme production in solid-state fermentation (SSF) by Lentinus edodes L-8. The total N content and lignocellulose contents of ammoniated corn stalk were determined for analysis of the effect of ammoniation pretreatment on lignocellulose structure. The variation patterns of enzyme activity were analyzed according to the enzyme data determined every 2 days during the fermentation. A 4% w/w high-temperature ammoniation pretreatment had a significant effect on cellulase production, and the highest enzyme activity reached almost triple that of the control group. The results also showed that ammoniation pretreatment inhibited the generation of ligninases, such that ligninases appeared later and at lower activities in experimental groups compared to the control group. PDF
Korean spruce (Picea koraiensis Nakai) is one of the most important wood resources for pulp and paper industry. However, a long production cycle is required for spruce to obtain mature timber, which may negatively influence the biomass production. In this study, fiber morphology, chemical composition, and pulping properties of Korean spruce with different tree ages and vertical locations were investigated. The results show that, along with the increase of tree ages, the contents of extractives, lignin, and pentosan increase to different extents. There are also some differences of pulping properties with different tree ages. As a pulpwood, the Korean spruce with tree ages of around 22 to 32 years is more suitable for kraft pulping, compared to that with 32-46 years. In addition, the middle segment of the bole had better pulp strength properties than the upper or lower bole segments. PDF
The physical and mechanical properties of poplar clones largely determine their suitability for various end-uses, especially for high value-added applications. The main objective of this study was to determine the clonal variation of selected physical and mechanical properties of seven hybrid poplar clones grown at three sites in southern Quebec, Canada. Five trees per clone were randomly sampled from each site for wood properties measurement. Site had a significant effect on all measured properties except radial shrinkage. All properties of hybrid poplar wood showed significant interclonal variation, indicating the possibility of identifying clones with superior wood properties, especially for density, flexural modulus of rupture, and ultimate crushing strength. High heritability values for the studied properties indicated that these properties are under moderate to high genetic control. The genetic gain for these wood properties ranged from 2.0% to 13.5%. PDF
Mohamad Ibrahim, M. N., Lim, S. L., Ahmed-Haras, M. R., and Fayyadh, F. S. (2014). "Preparation and characterization of lignin graft copolymer as a filtrate loss control agent for the hydrocarbon drilling industry," BioRes. 9(1), 1472-1487.
Lignin graft copolymer (LGC) was prepared using an addition polymerization technique that involved grafting a 2-acrylamido-2-methylpropane sulfonic acid (AMPS) monomer onto soda lignin (SL). The optimal polymerization conditions were found to be as follows: soda lignin, 2.0 g; initiator, 3% (w/w) potassium persulphate of SL; mass ratio of AMPS to SL, 1:2; reaction time, 7 h; and reaction temperature, 60 °C. The LGC was characterized using a Fourier transform infrared (FTIR) spectroscopy, a thermogravimetric analyzer (TGA), and gel permeation chromatography (GPC). The filtrate loss controlling ability of the LGC was evaluated using the American Petroleum Institute Recommended Practice 13-B 1 standard procedures. The results showed that the LGC has remarkable rheological and filtration controlling properties at both room temperature and high aging temperatures (190 °C). PDF
The present study was carried out to optimize the cultural conditions of phytase production by Aspergillus niger USM AI1 using palm kernel cake (PKC) as the substrate in a solid state fermentation (SSF) system. The optimized cultural conditions of 10 g of PKC with a particle size of ≤0.5 mm, an inoculum size of 1x105 spores/ mL, moisture content of 60% (v/w), and a mixing frequency of once every 48 hours produced 4.91±0.17 U/g dried substrate of phytase and 1.14±0.04 mg glucosamine/ g dried substrate of fungal growth. Maximum growth as well as enzyme production was recorded on the 4th day of cultivation at room temperature (30±2 ºC). The findings indicated that phytase production increased 171.3% after optimization (4.91±0.17 U/g dried substrate) compared to before optimization (1.81±0.16 U/g dried substrate). This study showed that PKC is a potential medium for phytase production in SSF. PDF
Kundu, A., Redzwan, G., Sahu, J. N., Mukherjee, S., Gupta, B. S., and Hashim, M. A. (2014). "Hexavalent chromium adsorption by a novel activated carbon prepared by microwave activation," BioRes. 9(1), 1498-1518.
Microwave heating reduces the preparation time and improves the adsorption quality of activated carbon. In this study, activated carbon was prepared by impregnation of palm kernel fiber with phosphoric acid followed by microwave activation. Three different types of activated carbon were prepared, having high surface areas of 872 m2 g-1, 1256 m2 g-1, and 952 m2 g-1 and pore volumes of 0.598 cc g-1, 1.010 cc g-1, and 0.778 cc g-1, respectively. The combined effects of the different process parameters, such as the initial adsorbate concentration, pH, and temperature, on adsorption efficiency were explored with the help of Box-Behnken design for response surface methodology (RSM). The adsorption rate could be expressed by a polynomial equation as the function of the independent variables. The hexavalent chromium adsorption rate was found to be 19.1 mg g-1 at the optimized conditions of the process parameters initial concentration of 60 mg L-1, pH of 3, and operating temperature of 50 ºC. Adsorption of Cr(VI) by the prepared activated carbon was spontaneous and followed second-order kinetics. The adsorption mechanism can be described by the Freundlich Isotherm model. The prepared activated carbon has demonstrated comparable performance to other available activated carbons for the adsorption of Cr(VI). PDF
Different thermo-mechanical extrusion pretreatments were evaluated as alternatives to traditional biomass pretreatments for lignocellulosic ethanol production. Wheat straw, a commonly available agricultural co-product, was chosen as the substrate model for the study. Five thermo-mechanical pretreatments were evaluated: one purely thermo-mechanical (TM) using just water, and the rest thermo-mechano-chemical (TMC), thus using acid, alkaline, oxidant in alkaline medium, and organic solvent. The parietal constituents, hemicelluloses, cellulose, and lignin were quantified to enable the amounts extracted by the pretreatment to be estimated. The digestibility of cellulose was evaluated by quantifying the hydrolysability with an enzyme cocktail. Water thermomechanical treatment gave strong straw defibration; however the digestibility only attained 35%, whereas ground wheat straw was already 22%. This improvement is insufficient to prepare material for direct enzymatic hydrolysis; thus a combination of the thermo-mechanical and chemical treatment is required. All chemical treatments produced greater improvements in cellulose digestibility. For the acidic treatments, hydrolysability was between 42 and 50%, and reached 89% with alkaline pretreatment. PDF
Turku, I., Nikolaeva, M., and Kärki, T. (2014). "The effect of fire retardants on the flammability, mechanical properties, and wettability of co-extruded PP-based wood-plastic composites," BioRes. 9(1), 1539-1551.
In this work, fire retardants (FRs) such as aluminum trihydroxide (ATH), zinc borate (ZB), melamine, graphite, and titanium oxide (TiO2) were loaded into the shell layer of a co-extruded polypropylene (PP)-based wood-plastic composite (WPC). The incorporated retardants reduced the peak of the heat release rate by 8 to 22%, depending on the type of FR. Other studied parameters, such as ignition time and mass loss rate, were improved after the FR loading. The total heat release decreased slightly (except for the graphite-WPC). The effective heat of combustion was independent of the presence of the FR or, in the case of graphite, slightly increased. Carbon monoxide production increased (ZB, graphite) or was not changed significantly (ATH, melamine, and TiO2). It was also observed that the tensile strength improved after the FR loading; however, the tensile modulus decreased, except for the graphite-WPC. The impact strength improved or was independent of the FR loading, as in the case of the sample with ATH. The wettability of the composites decreased with filler loading, except for ZB, which showed the highest water absorption value among the studied composites. PDF
Lee, K. M., Ngoh, G. C., Chua, A. S. M., Yoon, L. W., Ang, T. N., and Lee, M.-G. (2014). "Comparison study of different ionic liquid pretreatments in maximizing total reducing sugars recovery," BioRes. 9(1), 1552-1564.
A process scheme combining the most suitable ionic liquid pretreatment, followed by solid acid and enzymatic saccharification was used to maximize the reducing sugars recovery from sago waste. Three types of ionic liquids, i.e. 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]) and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][(EtO)2PO2]) were evaluated based on their performance in terms of the total reducing sugars recovery, chemical cost, and pretreatment energy requirement. The results showed that all the ionic liquids assisted the saccharification processes by dissolving and depolymerizing the carbohydrates of the sago waste into shorter chain soluble oligosaccharides, as well as disrupting the biomass structure to produce an amorphous pretreated solid residue. The solid acid saccharifications of the prehydrolysates obtained from the [BMIM]Cl pretreatment gave the highest reducing sugars recovery (61-63%) irrespective of the solid acid catalyst employed. On the other hand, enzymatic saccharification of [EMIM][OAc] pretreated solid residues showed the highest reducing sugars recovery (29%). A maximum recovery of 90% reducing sugars was achieved via incorporation of the ionic liquid pretreatment, solid acid and enzymatic saccharifications using [BMIM]Cl, Amberlyst 15 (A15) and Trichoderma viride cellulase respectively. This study suggests that the combined sequential process can maximize the reducing sugars recovery from sago waste effectively. PDF
The stability of tetra-n-butylphosphonium hydroxide ([P4444][OH](aq)) solutions and their potential for wheat straw extraction are investigated. Under certain concentration ranges, aqueous [P4444][OH](aq) is known to rapidly dissolve up to 20 wt% of cellulose at 25 ºC. However, at elevated temperatures and at the high concentration ranges required for cellulose dissolution, [P4444][OH](aq) irreversibly decomposes. This was determined by following the kinetics of decomposition at different temperatures and concentrations, using 31P NMR analysis of the solutions. A lower concentration range of 40 wt% [P4444][OH](aq) was observed for fractionation of wheat straw, avoiding significant decomposition of the expensive phosphonium component. Herein, the possibilities for producing cellulose-rich fractions with reduced lignin contents and hemicellulose-rich extracts are discussed. A proposal is given for a full process cycle using [P4444][OH](aq), where the phosphonium salt is used in fractionation and recovered by anion metathesis as a chloride salt. Although not demonstrated in this article, the chloride salt may be converted back to the hydroxide by means of, e.g., ion exchange. PDF
Yang, X., Zhang, R., Tang, L., Chen, M., Li, Y., and Zhou, X. (2014). "Dynamic wettability of different adhesives on wheat straw surface modified by cold oxygen plasma treatment," BioRes. 9(1), 1578-1587.
The effects of cold oxygen plasma treatment on the exterior and interior surfaces and wettability of wheat straw were investigated. The wheat straw was treated with oxygen plasma for 150 s, and the radio-frequency power was set at 100 W. The surface wettability was evaluated by measuring the contact angles and the K values of urea-formaldehyde, phenol-formaldehyde, and methylene diphenyl diisocyanate resins. Specimens with different gluing surfaces were bonded together with urea-formaldehyde and phenol-formaldehyde and then hot-pressed to assess bonding strength. Results indicate that the dynamic wettability and the shear strength of wheat straw were remarkably improved after it was exposed to the cold oxygen plasma. Additionally, the adhesive type and the wheat straw surface characteristics had significant effects on the dynamic wettability and bonding strength of both untreated and plasma-treated wheat straw. PDF
Ahsan, L., Jahan, M. S., Khan, M. I. H., and Calhoun, L. (2014). "Recovery of acetic acid from prehydrolysis liquor of kraft hardwood dissolving pulp using ion-exchange resin," BioRes. 9(1), 1588-1595.
The growing demand for rayon and cellulosic products has resulted in the conversion of a number of kraft pulp mills into dissolving pulp mills in recent years. In fact, kraft-based dissolving pulp production fits well into the concept of an integrated forest biorefinery, in particular, the utilization of dissolved organics in the pre-hydrolysis liquor (PHL) for bio-materials and bio-energy purposes. In this study, the recovery of acetic acid, the second major component in the PHL of the kraft-based hardwood dissolving pulp production process, was investigated using amine-based resin adsorption. Activated carbon (AC) adsorption was adopted as the first step to remove the lignin, and six AC samples were evaluated for this purpose. Among them, CR325 W-Ultra Powder AC showed the best result and removed about 90% of lignin with a minimal loss of hemicellulosic sugars and acetic acid from PHL at a ratio of 1:20 (AC:PHL). Subsequently, the adsorption of acetic acid from AC-treated PHL (TPHL) was studied on tertiary and quaternary amine-based resins. The tertiary amine resin demonstrated better adsorption efficiency. Desorption of the adsorbed acetic acid from the amine resin using sodium hydroxide solution was also studied, and the results showed that 66 to 84% acetic acid desorption occurred using a 4% NaOH solution. PDF
Castor (Ricinus communis L.) stalk is a byproduct of the production of castor oil. As a natural material, castor stalk has great potential in the production of bio-composites as reinforcement materials. To provide more information about the castor stalk for using it better, the structure, microfibril angle (MFA), relative degree of crystallinity (%), and mechanical properties of castor fiber cell walls were investigated using X-ray diffraction (XRD) and nanoindentation. The influence of chemical composition and MFA on the mechanical properties of fiber cell wall was studied as well. The cortex of castor stalks primarily contains long fibers, while the xylem of castor stalk, an excellent wood-type material, comprises most of the castor stalk (83.95% by weight); the pith of the stalk is composed of parenchyma cells. The average elastic modulus of fiber cell wall in lower, upper, and branch parts are 16.0 GPa, 18.6 GPa, and 13.2 GPa, respectively. The average hardness of fiber cell wall in lower, upper, and branch parts are 0.50 GPa, 0.54 GPa, and 0.43 GPa, respectively. As lignin content increases from 15.57% to 17.41% and MFA decreases from 21.3˚ to 15.4˚, the elastic modulus increases from 13.2 GPa to 18.6 GPa and the hardness increases from 0.43 GPa to 0.54 GPa. The mechanical properties, including the elastic modulus and the hardness of the fiber cell wall in the upper region of the castor stalk, are higher than those in the lower region, while the mechanical properties of the fiber cell wall in the branches are lower than those in either the upper or lower regions. PDF
The world seems to be raising its energy needs owing to an expanding population and people’s desire for higher living standards. Diversification biofuel sources have become an important energy issue in recent times. Among the various resources, algal biomass has received much attention in the recent years due to its relatively high growth rate, its vast potential to reduce greenhouse gas (GHG) emissions and climate change, and their ability to store high amounts of lipids and carbohydrates. These versatile organisms can also be used for the production of biofuel. In this review, sustainability and the viability of algae as an up-coming biofuel feedstock have been discussed. Additionally, this review offers an overview of the status of biofuel production through algal biomass and progress made so far in this area. PDF
Paper production requires large amounts of cellulosic fiber, whereas the world’s forested lands and croplands have a finite capacity to supply such resources. To deal with likely future pressure on forest resources, as well as to hold down costs of materials, publications examined in the preparation of this review suggest that the paper industry will need to implement several concurrent strategies. In particular, the industry can be expected to view recycling as a central part of its activities. Basis weights of various paper-based products can be expected to decrease over the coming decades, and more of the fiber content will be replaced with fillers such as calcium carbonate. Such trends will place intense demands upon chemical-based strategies to enhance the bonding within paper and paperboard. Based on the literature, further progress in reducing the amount of new forest resources used to meet a given set of paper product requirements will require a combined approach, taking into account various fiber attributes, nanostructures, novel concepts in bond formation, and advances in the unit operations of papermaking. PDF
Many bio-based materials, which have lower environmental impact than traditional synthetic materials, show good sound absorbing and sound insulation performances. This review highlights progress in sound transmission properties of bio-based materials and provides a comprehensive account of various multiporous bio-based materials and multilayered structures used in sound absorption and insulation products. Furthermore, principal models of sound transmission are discussed in order to aid in an understanding of sound transmission properties of bio-based materials. In addition, the review presents discussions on the composite structure optimization and future research in using co-extruded wood plastic composite for sound insulation control. This review contributes to the body of knowledge on the sound transmission properties of bio-based materials, provides a better understanding of the models of some multiporous bio-based materials and multilayered structures, and contributes to the wider adoption of bio-based materials as sound absorbers. PDF
Natural biomacromolecules constitute a diverse feedstock, including carbohydrate-based polysaccharides (cellulose, hemicellulose, starch, agarose, and Konjac glucomannan) together with lignin — extracted mainly from biomass — and other protein based polymers, namely keratin, chitin, chitosan, and silk fibroin. The complex and heterogeneous chemical structure of biomacromolecules makes them difficult to dissolve and disintegrate into simpler molecules for further applications. In this regard, ionic liquids are potential solvents for the dissolution and modification of long chain biopolymers. This provides a promising pretreatment technology and is known to allow adequate extraction of biopolymers from natural sources. This paper highlights the properties of ionic liquids for their use as versatile solvents. This review provides a critical outlook regarding the influence of several process parameters that govern the fractionation of biomacromolecules into their constituent elements and further pretreatment processes. The performance of different types of ionic liquids for processing of biomacromolecules, focusing on their pertinent capability as catalysts to enhance the rate of hydrolysis, also is discussed in this article. PDF