Volume 6 Issue 3
- Researchpp 3313-3323Samariha, A., and Khakifirooz, A. (2011). "Application of NSSC pulping to sugarcane bagasse," BioRes. 6(3), 3313-3323.AbstractArticlePDF
The NSSC pulping process was investigated to produce pulp from bagasse for corrugating board manufacture. The chemical contents including cellulose, lignin, ash, and extractives soluble in alcohol-acetone measured 55.75, 20.5, 1.85, and 3.25, respectively. The average fiber length, fiber diameter, lumen width, and cell wall thickness of bagasse were 1.59 mm, 20.96, 9.72, and 5.64 μm, respectively. The optimum conditions, with a yield of 74.95%, were achieved using 20 percent chemicals on the basis of sodium oxide, cooking temperature of 170 °C, and cooking time of 30 minutes. Pulp was refined to freeness 345 and 433 mL CSF according to Canadian standards. 127 g m-2 handsheets from both pulps were made and strength properties measured. Statistical analysis of results indicated that paper derived from freeness 345 and 433 mL CSF had better strength properties in all indices in comparison with NSSC pulp from hardwoods produced at Mazandaran Pulp and Paper factory, Iran.
- Researchpp 3324-3338Mahajan, G., and Sud, D. (2011). "Kinetics and equilibrium studies of Cr(VI) metal ion remediation by Arachis hypogea shells: A green approach," BioRes. 6(3), 3324-3338.AbstractArticlePDF
Arachis hypogea shells (ground nut shells), a lignocellulosic waste biomass, was evaluated for sequestering of Cr(VI) from synthetic wastewater. Arachis hypogea shells (AHS) were used in three different forms, viz. natural (AHSN), immobilized in the form of beads (AHSB), and in the form of activated carbon (AHSC). Batch experiments were performed for the removal of hexavalent chromium. Effects of pH adsorbent dose, initial metal ion concentration, stirring speed, and contact time were investigated. The removal of metal ions was dependent on the physico-chemical characteristics of the adsorbent, adsorbate concentration, and other studied process parameters. Maximum metal removal for Cr(VI) was observed at pH 2.0. The experimental data were analyzed based on Freundlich and Langmuir adsorption isotherms. Kinetic studies indicated that the adsorption of metal ions followed a pseudo-second-order equation.
- Researchpp 3339-3351Wang, W., Zhao, Z., Gao, Z., and Guo, M. (2011). "Whey protein-based water-resistant and environmentally safe adhesives for plywood," BioRes. 6(3), 3339-3351.AbstractArticlePDF
Whey protein is a renewable and environmentally safe biomaterial, a by-product of cheese production. It can be utilized for non-food applications for value-added products. The substances glyoxal (GO), glutaraldehyde (GA), polymeric methylene biphenyl diisocyanate (p-MDI), urea-formaldehyde (UF) resin, and phenol-formaldehyde oligomer (PFO) that contain reactive groups were applied together with whey protein as modifier in order to increase crosslinking density and molecular weight for improving the bond strength and water resistance of whey protein. A water-resistant and environmentally safe whey protein-based wood adhesive for plywood was developed by evaluating the effects of these modifiers on the bond strength, bond durability, and free formaldehyde emission of the resulting plywood panels. Results of FTIR and SEM analyses and bond evaluation indicated that GO, GA, and p-MDI were not suitable to modify whey proteins due to their high reactivity with whey proteins, causing phase separation. UF resin was not a good modifier for whey proteins because of either its poor water-resistance or higher emission of hazardous formaldehyde. Whey protein adhesives modified with PFO had a dry shear bond strength of 1.98 MPa and a 28h-boiling-dry-boiling wet shear strength of 1.73 MPa, which were both much higher than the required values for structural use according to standard JIS K6806-2003, while its formaldehyde emission was 0.067mg/L, much lower than the required value for green plywood according to standard JIS A5908.
- Researchpp 3352-3362Hein, P. R. G., and Brancheriau, L. (2011). "Radial variation of microfibril angle and wood density and their relationships in 14-year-old Eucalyptus urophylla S. T. Blake wood," BioRes. 6(3), 3352-3362.AbstractArticlePDF
The orientation of cellulose microfibrils in the cell wall along the stem axis has major effects on stiffness and longitudinal shrinkage and is of key importance in wood quality. The aim of this study was to investigate the radial variability of MFA and wood density (ρ) and their relationships in Eucalyptus urophylla wood. Three MFA values were estimated by X-ray diffraction at three points of each one of the 175 tangential sections, and the basic density was measured. A decrease of microfibril angles from pith to bark can be observed in most samples; however, some radial strips presented different patterns of variation. For basic density, a linear significant increase from pith to bark was confirmed. There was no significant correlation between microfibril angle and density. The relationships among the three MFA estimated on tangential sections of wood were strong. The “curvature effect” due to the growth rings had a negligible effect on the three measurements of tangential sections cut near to the pith. This study showed that a single T value measurement by X-ray diffraction, preferably at the centre of the tangential section, is precisely sufficient to estimate the mean MFA of Eucalyptus urophylla wood.
- Researchpp 3363-3375Olivella, M. À., Jové, P., Şen, A., Pereira, H., Villaescusa, I., and Fiol, N. (2011). "Sorption performance of Quercus cerris cork with polycyclic aromatic hydrocarbons and toxicity testing," BioRes. 6(3), 3363-3375.AbstractArticlePDF
Quercus cerris is an important oak species extended in large areas of Eastern Europe and Minor Asia that has a thick bark which is not utilized at all. The sorption performance of cork from Quercus cerris bark with four polycyclic aromatic hydrocarbons (PAHs) (acenaphthene, fluorene, phenanthrene, and anthracene) was investigated. Quercus cerris cork was characterized for elemental analysis, acidic groups, and summative chemical composition, and the results were compared with Quercus suber cork. A Microtox® test was carried out to test for the release of any toxic compounds into the solution. All isotherms fit the Freundlich model and displayed linear n values. Quercus cerris exhibited a high efficiency for sorption of PAHs for the studied concentrations (5 to 50 µg/L) with 80-96% removal, while the desorption isotherms showed a very low release of the adsorbed PAHs (<2%). In relation to Quercus suber cork, KF values of Quercus cerris cork are about three times lower. The quantity of Quercus cerris cork required to reduce water pollution by PAHs was estimated to be less than twice the quantity of other adsorbents such as aspen wood and leonardite. Toxicity tests indicated that non-toxic compounds were released into the solution by the Quercus cerris and Quercus suber cork samples. Overall the results indicate the potential use of Quercus cerris cork and of Quercus suber cork as effective and economical biosorbents for the treatment of PAH-contaminated waters.
- Researchpp 3376-3395Neto, V. O. S., Oliveira, A. G., Teixeira, R. N. P., Silva, M. A. A., Freire, P. T. C., Keukeleire, D. D., and Nascimento, R. F. (2011). "Use of coconut bagasse as alternative adsorbent for separation of copper(II) ions from aqueous solutions: Isotherms, kinetics, and thermodynamic studies," BioRes. 6(3), 3376-3395.AbstractArticlePDF
The use of coconut bagasse as an adsorbent for the treatment of Cu(II) ions from aqueous solutions has been investigated. The adsorbent was characterized by infrared spectroscopy, including zeta potential and pH effects. To assess the possibility of removing Cu(II) from aqueous solutions by this sorbent the effects of contact time, initial metal ion concentration, and temperature were studied at pH 5.5. Kinetic studies showed that the amount adsorbed increased with initial Cu(II) concentration, and the equilibrium was established in 120 min. The kinetic data were analyzed using a pseudo second-order equation. Adsorption equilibrium data were investigated using the Langmiur, Freundlich, D–R, Temkin and Halsey isotherm models. The adsorption of Cu(II) on the coconut bagasse was endothermic (DH◦ 86.2 kJ/mol), resulting in an increase in entropy (DS◦ 339 J/mol/K) and a decrease in Gibbs free energy (DG -16.34 to -22.44 kJ/mol) in the temperature range of 301-313 K. A reduction in adsorption capacity with an increase in heat of adsorption revealed an ion exchange mechanism for Cu(II) adsorption.
- Researchpp 3396-3409Wu, W.-B., Jing, Y., Gong, M.-R., Zhou, X.-F., and Dai, H.-Q. (2011). "Preparation and properties of magnetic cellulose fiber composites," BioRes. 6(3), 3396-3409.AbstractArticlePDF
Magnetic cellulose fiber composites were prepared by a “vacuum-lumen-loading” method with polyethylenimine (PEI) as retention aid. The composites thus formed preserved the inherent properties of the cellulose fiber and gained the magnetically responsive properties of nanoparticles. Magnetic paper was further made from the composites. These materials were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, a vibrating sample magnetometer, and paper testers. There was a large amount of magnetic nanoparticles deposited on the exterior, in the pores, and especially in the lumen of fibers. Lumen loading of nanoparticles is favored by pulp beating, silica shell modification of magnetite, vacuum conditioning, and usage of PEI. The physical strength of paper was reduced to a certain extent because of unavoidable deposition of nanoparticles on the exterior of fibers, which could block the formation of hydrogen bonding between fibers. Our results show that both the cellulose fiber composites and the resulting paper possessed good superparamagnetism with tiny remnant magnetization and coercivity. These materials will allow the investigation of new concepts in paper making and packaging, security paper, and information storage.
- Researchpp 3410-3423Chen, Y., Qian, X., and An, X. (2011). "Preparation and characterization of conductive paper via in situ polymerization of 3,4-ethylenedioxythiophene," BioRes. 6(3), 3410-3423.AbstractArticlePDF
Conductive paper was prepared via in situ chemical oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) in pulp suspension by using iron(III) p-toluenesulfonate (Fe(OTs)3) as both an oxidant and a dopant source. The deposition of poly(3,4-ethylenedioxythiophene) (PEDOT) on the pulp fiber surface was verified and characterized by ATR-FTIR and SEM analyses. The factors affecting the conductivity of the PEDOT-coated paper were investigated, and the preparation conditions of the conductive paper with a low resistivity and excellent environmental stability was obtained. The optimum reaction temperature and time were 60 °C and 4 h, respectively. The molar ratio of EDOT to Fe(OTs)3 of 1:1 was optimal when considering both cost and performance factors. The conductivity of the PEDOT-coated paper could be controlled by adjusting EDOT concentration. The threshold concentration of EDOT was about 3 g·L-1, and a volume resistivity as low as 5.9103 Ω·cm could be achieved, which reached the conductivity range of an electrical conductor. The environmental stability of the PEDOT-coated conductive paper was very good due to the much higher oxidation potential of PEDOT.
- Researchpp 3424-3439Tsoi, W.-Y. I., Kan, C.-W., and Yuan, C.-W. M. (2011). "Using ageing effect for hydrophobic modification of cotton fabric with atmospheric pressure plasma," BioRes. 6(3), 3424-3439.AbstractArticlePDF
A hydrophobic modification of cotton fabric was demonstrated with atmospheric pressure plasma treatment with oxygen as the reactive gas. Oxygen plasma was determined to be capable of inducing hydrophobic modification of cotton fabric surface by utilizing the ageing effect. Upon ageing, the surface polarity was reversed and hydrophobic aliphatic hydrocarbons were formed, which was confirmed by Fourier Transform Infrared Spectroscopy. Surface hydrophobicity was quantified by the wetting area measurement. Wetted area of plasma-modified cotton was found to be strongly dependent on plasma-induced surface structures and the chemical composition on the fiber surface. Scanning electron microscopy revealed that physical morphological alteration was also a crucial factor that contributed to surface hydrophobicity. This work seeks to determine a controlled hydrophobic modification of textile materials through optimization of plasma process based on the Orthogonal Array Testing Strategy (OATS). Optimum process conditions were determined based on reduction of wetted area of plasma-modified cotton fabrics. Finally, hydrophobicity of plasma-modified cotton fabric was compared with conventional water repellency treatment.
- Researchpp 3440-3451Zhong, W., Yu, H., Song, L., and Zhang, X. (2011). "Combined pretreatment with white-rot fungus and alkali at near room-temperature for improving saccharificaiton of corn stalks," BioRes. 6(3), 3440-3451.AbstractArticlePDF
Although biological pretreatment has the advantages of being environmentally friendly and having low-energy consumption, it usually requires a relatively long incubation time. In this study, a novel combined pretreatment with white-rot fungus and alkali at near room-temperature for saccharification of corn stalks was investigated to speed up the biological process. Biological pretreatment with Irpex lacteus or Echinodontium taxodii can improve enzymatic hydrolysis of corn stalk greatly, but the process requires a long time (60 days) to achieve a satisfactory sugar yield. The combination processes with the fungi were compared with the sole pretreatments. The results showed that the time of the biological process could be shortened to 15 days when the bio-treatment with I. lacteus was combined with alkali pretreatment. The efficiency of alkali pretreatment can be also enhanced significantly by biological treatment. 271.1mg/g of final glucose yield was obtained for the combination pretreatment, which was an improvement of 50.4% and 28.3% in comparison with the sole alkali pretreatment at the same and optimum reaction time, respectively. In conclusion, the combination of biological pretreatment with alkali processes not only speeded up the biological process, but also improved the sugar yield in comparison to the sole pretreatment and is favorable for the development of biological pretreatment.