Research Articles

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).

The goal of this study was to survey the feasibility of the biosorption of Reactive Black 5 (RB5) from aqueous solutions using biomass prepared from potato peel waste. Adsorption isotherms were constructed, and the kinetics of dye adsorption were studied. Langmuir and Freundlich isotherms were constructed, and pseudo-first order, pseudo-second order, and modified pseudo-first order kinetic models were studied. Maximum adsorption (85.5%) was observed at a pH of 3, and uptake decreased with increasing pH. The biosorption of RB5 increased with increasing contact time and reached equilibrium after two hours. RB5 removal efficiency decreased with an increase in the initial dye concentration, but the uptake of dye increased. Adsorption data conformed to the Langmuir isotherm model and pseudo-first order kinetics.

Biomass pretreatment by autohydrolysis uses hot-water to extract soluble components from wood prior to converting the woody residuals into paper, wood products, or fuel, etc. Mixed hardwood chips were autohydrolyzed in hot-water at 150, 160, 170, and 180 ºC, for 1 and 2 h. The tradeoff between fermentable sugar yield and caloric value of the residual solids was studied for a process that will be referred to as “value prior to combustion”. The extracted liquid was treated with dilute sulfuric acid to break down sugar oligomers into fermentable monomers. Material balances were performed around autohydrolysis to evaluate the role of temperature and residence time on sugar production and residual solid heating value. The composition (sugars and byproducts) of the extracted liquid was determined. As the autohydrolysis temperature increased, the material balance became less precise, presumably due to more volatile byproducts being formed that were not quantified. More hemicelluloses were extracted from the wood by the hot water extraction process under higher temperature and longer residence time, but a greater degree of sugar degradation was also observed. After hot-water extraction the heating value of the solid residues was higher than the original wood. The total energy content of the residual solid after extraction ranged from 74 to 95% of the original energy content of the feed.

The Young’s modulus and the in-plane shear modulus of medium-density fiberboard (MDF) were obtained by conducting a flexural vibration test under the free-free condition based on Timoshenko’s vibration theory using specimens with various depth/length ratios and performing a subsequent numerical analysis. The results obtained by the experiment and numerical analysis revealed that the Young’s modulus was independent of the specimen configuration. In contrast, the in-plane shear modulus was significantly dependent on the specimen configuration and could not be measured properly based on Timoshenko’s theory when the specimen had a small depth/length ratio. The numerical analysis also revealed that the Poisson’s ratio has a significant influence on the measurement of shear modulus as well as the specimen configuration. A statistical analysis on the results experimentally obtained suggested that the length of the specimen must be less than 7.5 times the depth to measure the in-plane shear modulus appropriately.

Experimental eight-ply laminated veneer lumbers (LVLs) from rotary peeled I-214 (Populus x Euramericana) and I-77/51 (Populus deltoides)fast growing hybrid poplar clones were successfully manufactured using three different press durations (18, 24, and 30 min) with a melamine urea formaldehyde (MUF) adhesive. The effect of press durations on LVLs’ selected physical, mechanical, and combustibility characteristics were determined. The results showed that press duration affected dimensional stability (thickness swelling and water absorption), modulus of rupture, and/or compression strength parallel to grain, depending on the clone types. Improvement in dimensional stability and some mechanical properties of LVLs can be achieved by proper curing of the MUF adhesive. On the other hand, the press durations did not affect oven-dry densities, modulus of elasticity, and the combustibility (weight loss after completion of the test). For improved physical and mechanical properties, up to a 30 min press duration can be recommended. This is necessary for LVLs when they are to be used under conditions where water and/or high humidity is present.

In this study we analyze changes in United States imports of wood furniture over the 39-year period from 1972 to 2010. In 1972, Canada and the former Yugoslavia were the most important sources of imported wood furniture, and Europe accounted for nearly 60 percent of total imports. Shipments of low-cost wood furniture from Taiwan started to increase in the 1970s, and by 1978, Taiwan was the most important source of imported wood furniture. Overall, low-cost sources in Asia displaced Europe in 1987. Taiwan continued to be the most important source until 1994. Canada became the most important source of imported wood furniture from 1994 to 2000 as the Canadian dollar declined in value against the United States dollar. In 2001, China became the most important source of wood furniture imports. More recently furniture imports from an emerging source, Vietnam, have increased dramatically. One reason why Asian manufacturers have been so successful in the U.S. market has been that furniture consumers were influenced mainly by price. By contrast, success in some segments of the U.S.-based furniture industry indicates that models enabling consumers to make styling and pricing decisions also can be competitive.