Volume 6 Issue 4

Plantation-grown wood species are becoming more important. Their anatomical, physical, and mechanical properties are different and generally more variable than wood grown in natural stands. The objective of this study was to investigate the wettability and surface roughness (SR) of natural and plantation-grown narrow-leaved ash (Fraxinus angustifolia Vahl.) wood. The logs were cut from a natural stand versus three different spacings of plantation-grown narrow-leaved ash wood stands. Plantation spacings were 3 x 2 m, 3 x 2.5 m, and 4 x 4 m. The wetting behavior of the wood samples was characterized by the contact angle (CA) method (goniometer technique). A stylus type profilometer was used for the SR measurement according to the DIN 4768 (1990) standard. The SR and CA measurements were done on both the radial and tangential surfaces of the samples. Individual values of both SR and CA of ash wood showed statistically significant differences. Based on the findings, it appears that the natural-grown ash wood have higher (less favorable) SR and lower (more favorable) CA values compared to all the plantation-grown ash wood on both radial and tangential surfaces. Tangential surfaces had lower SR values and higher CA values than the radial surfaces for all groups. In conclusion, plantation-grown narrow-leaved ash wood can be utilized for bonded wood products such as plywood, laminated veneer lumber, and glulam.

This paper reports a simple innovative method to align magnetic cellulose fibers by using a simple permanent magnet to fabricate unidirectional magnetic papers. Magnetic cellulose fibers were made by in situ synthesis of magnetite nanoparticles on alpha cellulose pulp extracted from American southern pine. Scanning electron microscope micrographs and energy dispersive X-ray spectroscopy maps indicated that magnetite nanoparticles completely covered the cellulose fibers. Suspensions of magnetic cellulose fibers were prepared at three levels of concentration (0.02, 0.04, and 0.08 g/L) and poured into the designed magnetic forming machine. Flow rate of suspension into the forming column was adjusted at 0, 0.3, 0.5, and 1 cm/s. The strength of the applied external magnetic field was the same in all cases and lower than 0.18 T. Orientation analysis indicated that the designed magnetic forming machine has a high performance to be used for aligning magnetic cellulose fibers and fabricating unidirectional magnetic cellulose papers. Observed anisotropic magnetic and mechanical properties confirmed the unidirectional structure.

Enzymatic hydrolysis of sludge from a bleached tissue mill generates glucose that can be sold as a product or sent to an ethanol plant. Hydrolysis rates using enzymes from two sources are reported, and a configuration for the industrial conversion of sludge to glucose is proposed. The system combines a set of stirred tank reactors with ash removal and membrane filtration to give a glucose concentrate. The economics of the conversion are attractive.

Wood pyrolysis oil consists of hundreds of complex compounds, many of which are phenolic-based and exhibit hydrophobic properties. Southern yellow pine was impregnated with a pyrolysis oil-based penetrant using both a high pressure and vacuum impregnation systems, with no significant differences in retention levels. Penetrant concentrations ranging from 5-50% pyrolysis oil/methanol on a volume basis were used to determine the threshold concentration for significant physical property improvement. Wood impregnated with penetrant concentration of at least 10% exhibited significant reduction in both moisture sorption and tangential swelling when exposed to a 90% relative humidity and 21°C environment. When exposed to liquid water in a 24-hour soak test, analysis revealed a negative linear relationship between penetrant concentration and both moisture sorption and tangential swell. However, during the course of the 24-hour soak test, a significant linear relationship between penetrant concentration and leachate was determined.

The aims of this study were to investigate the physicochemical changes and microbial population during co-composting of 1 ton oil palm frond (OPF) with 1,000 L palm oil mill effluent (POME) anaerobic sludge. In the first 30 days of composting, the temperature of the composting piles was observed in the thermophilic phase, within a range of 50 - 56oC. Meanwhile, the oxygen level, moisture content, and pH profiles of the compost were maintained at 2.0 to 12%, 60 to 70%, and 7.9 to 8.5, respectively, throughout the composting process. The total bacteria count was estimated to be about 55 x 1010 CFU/mL in the mesophilic phase, and then it increased up to 66 x 1010 CFU/mL in the thermophilic phase, and finally decreased to 9.0x1010 CFU/mL in the curing phase. The initial C/N ratio, 64, decreased to 18 after 60 days of composting process, indicating the maturity of compost product from OPF-POME anaerobic sludge. The diversity of the bacterial community was investigated using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis. The results suggested that the co-composting process of OPF with POME anaerobic sludge was dominated by Pseudomonas sp.

Using standard methods for the determination of approximate analysis, ultimate analysis, and calorific value, the thermochemical properties of driftwood have been analyzed in the present study. The preliminary results showed that woody waste obviously comprised a large percentage of volatile matter at 72.56 ± 4.58 wt%. The molar ratio of hydrogen to carbon (H/C) was about 1.1, which was lower than those of cellulose (H/C = 1.67) and hemicellulose (H/C = 1.6), and seemed to be in accordance with its higher heating value (18.7 MJ/kg). However, the content of nitrogen was slightly higher, suggesting that the emissions of nitrogen oxide gases from biomass-to-heat facilities will arouse concern. Under the carbonization temperature of around 500 oC, the calorific value (25.5 MJ/kg) of the resulting biochar from driftwood was relatively enhanced. Based on the 1,000,000 tons driftwood in Taiwan and the Tier 1 method recommended by the Intergovernmental Panel on Climate Change (IPCC), the environmental benefit of mitigating greenhouse gas emissions and the economic benefit of selling electricity were preliminarily calculated to be around 1.5 × 10 6 tons and US$ 7.0 × 10 7, respectively.

Ionic liquids that dissolve cellulose provide an option to pretreat lignocellulosic biomass. In this study, potential application of three ionic liquids in pretreating rice husk and their abilities in dissolving rice husk cellulose were investigated. The ionic liquids applied were 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP). Dissolution of rice husk was conducted by heating 1.5% (w/v) rice husk-ionic liquid mixture at 100oC for 20 hours. The dissolved cellulose was subsequently regenerated with deionised water. All the ionic liquids were able to dissolve rice husk cellulose to varying extents, with the highest dissolution (36.7%) given by [EMIM]OAc followed by [BMIM]Cl (31.3%) and [EMIM]DEP (16.0%) at the 10th hour of heating. All the regenerated cellulose were found to be more amorphous as compared to the untreated rice husk. The energy study showed that both [EMIM]OAc and [BMIM]Cl had lower energy requirement compared to [EMIM]DEP. The results of energy requirement complemented the findings of dissolution ability of the ionic liquid. Both [EMIM]OAc and [BMIM]Cl are potential ionic liquids to be used in the pretreatment of rice husk, as they dissolved rice husk equally well.

Ten industrial fully bleached hardwood pulps representing very different brightness reversion profiles were evaluated. The pulps were characterized before and after brightness reversion. The aging method (dry, wet, high/low RH, high/low temperature, short/long time) had, in most cases, no effect on overall brightness reversion trends, but affected the absolute reversion values significantly. Relative humidity in the range of 50 to 90% influenced reversion much more than temperatures in the range from 30 to 45°C. Dry and wet heat-induced brightness reversion correlated positively and significantly with hexenuronic acid (HexA) content in the pulp. The brightness reversion causes a significant decrease in pulp viscosity values, and HexA thus causing decrease of kappa number. Modern pulps produced by TCF and light ECF bleaching technologies were more prone to brightness reversion than regular ECF pulps, partly due to the higher content of HexA. At a pH level above 8, the brightness reversion process was strongly retarded for pulps with a very high HexA content.

The effects of alkaline treatment and a compatibilizing agent on the tensile properties of sugar palm fibre-reinforced high impact polystyrene (HIPS) composites were studied. Two concentrations of an alkali solution (4% and 6%) and two percentages of a compatibilizing agent (2% and 3%) were used in this study. The alkaline treatment was carried out by immersing the fibres in 4% and 6% alkali solutions for 1 hour. A 40 wt. % of sugar palm fibre (SPF) was blended with HIPS and the compatibilizing agent using a Brabender melt mixer at 165 °C. All the treated fiber composites showed tensile strength enhancement compared with untreated composites. The maximum strength increase was 35%, which was achieved by 4% alkali treatment; however, there was no improvement in the tensile modulus.

In this research, char was prepared from Switchgrass (Panicum virgatum) cave-in-rock species and characterized from the perspective of value addition either as a soil amendment or as a feedstock for energy production. Char from torrefaction/pyrolysis was produced in a fixed bed lab-scale reactor, using a N2 flow at three temperatures (300, 400, and 500°C) and for two residency times (2.5 and 5 minutes). Proximate and ultimate analyses as well as calorific value tests were done on each of the chars obtained. Chars scanning electron microscopy (SEM) pictures were taken. Organic composition of char leachates was characterized using gas chromatography-mass spectrometry (GC-MS) following a Soxhlet extraction with dichloromethane. Char was analyzed using FTIR-ATR. No significant difference was observed in most char characteristics between 2.5 and 5 min residency times, for each temperature studied. Among the compounds identified, two may be of particular interest with respect to the biochar domain. 1-undecanol, a compound commonly used as a growth regulator in agriculture, was observed in 300 and 400°C chars for 5 and 2.5 min residence time, respectively. Naphthalene, commonly used as an ingredient in pesticide products, was the only polycyclic aromatic hydrocarbon (PAH) observed in chars and was found solely in the extracts obtained from the char produced at 500 °C (for both residency times).