Volume 8 Issue 4

Moisture content (MC) has an important effect on the performance of wood in service. In an attempt to rapidly and non-destructively acquire the MC of heat-treated wood, a radio frequency-type moisture meter was used to take the MC of 170, 185, and 200 °C heat-treated Manchurian ash and Mongolian pine wood samples as well as reference (conventional kiln-dried) samples. A linear regression analysis was applied to assess the relationship between the MC values obtained using the meter and those obtained using the oven-dry method by fitting the data points according to the least squares method. From the results of the high coefficients of determination of the regression equation, it was concluded that the meter could be effectively used to obtain the MC of heat-treated wood. Finally, to ensure the simple and reliable application of the meter, the meter correction factors corresponding to each species and heat treatment temperature were calculated and listed.

In this work, the possibility of using neutral sulfite semi-chemical (NSSC) bagasse pulp mixed with hardwood chemimechanical pulp (CMP) and bleached softwood kraft pulp (BSKP) was investigated with the aim of reducing hardwood and BSKP consumption. The bagasse NSSC pulp had a digester yield of about 73% and was unbleached. It was refined by a PFI mill to 400 mL CSF, but in the case of the hardwood CMP and imported long fiber pulp, the final refined freeness were selected to be 350 and 500 mL CSF. Handsheets were made (60 gm^-2), and their strength indices and optical properties were measured. Results of this research on a laboratory scale indicated that using bagasse NSSC pulp mixed with hardwood CMP to make newsprint with acceptable quality is possible, and this process will also noticeably reduce the consumption of imported long fiber pulp and wood for producing the grades of paper usually made from CMP.

In this study, blended paper was prepared by blending synthetic polyethylene (PE) via a disintegration technique. The produced paper was targeted to resist water or moisture. Unbleached kenaf whole stem pulp was used as the main source of fibre in making the paper. The pulp was blended with two types of PE: low-branched (LB) and high-branched (HB) polymers. To study the effect of PE addition to the paper, the water absorbency and mechanical properties were characterized. The pulp to PE mixtures were prepared at ratios of 9:1, 8:2, 7:3, 6:4, and 5:5. Scanning electron microscopy (SEM) showed that the PE was melted between the fibre linkages. The Cobb test determined that the blended paper absorbed less than 20 g/m2 of water within 60 s. The best water contact angle successfully achieved was at 84°, which is almost hydrophobic. The mechanical properties, such as tensile strength and tear strength, were in the range of accepted standard requirements. The obtained results indicated that blending via a disintegration technique can be applied in the process of making water-resistant paper. The produced paper is suitable for the manufacturing of water-resistant corrugated packaging materials.

Three kinds of wheat straw black liquor were extracted by alkaline solution at 25 °C, 100 °C, and 165 °C, and were precipitated by the stepwise addition of acid to pH 10.5, 9.0, and 2.0, respectively. The corresponding three lignin fractions were isolated. The characteristics of these lignin fractions were investigated, and their impacts on anti-oxidant properties were evaluated. The pH 10.5 fractions with low lignin content, low phenolic hydroxyl content, and high lignin molecular weight showed very poor radical scavenging ability. The pH 9.0 and 2.0 fractions with high phenolic hydroxyl contents exhibited excellent radical scavenging ability. The major portion of the degraded lignin was precipitated in the pH 2.0 fraction, resulting in a lower molecular weight and higher phenolic hydroxyl content as compared to the pH 10.5 and pH 9.0 fractions. The high extraction temperature degraded more lignin and generated more phenolic hydroxyl groups. Therefore, the lignin fractions extracted at 165 °C exhibited the best radical trapping potential as compared to the lignin extracted at 100 °C and 25 °C. The coefficients of DPPH· removal for the lignin fractions were ordered in sequence by phenolic hydroxyl content, methoxyl content, molecular weight, E+T content, and NO yield of lignin. The lignin fraction extracted at higher temperature and precipitated at lower pH had the best radical scavenging ability.

In the present study, jatropha oil cake (JOC), a waste produced from processing jatropha seeds for biodiesel production, has been investigated for the removal of nickel (II) from aqueous solutions. Jatropha oil cake contains different functional groups that can participate in the metal ion complexation. Jatropha oil cake is used in its natural form (JOCN) as well as in its immobilized form (JOCB). Batch experiments were performed for adsorption of Ni (II) by JOCN and JOCB. Parameters affecting the adsorption, such as the effect of adsorbent dose, pH, the initial concentration of metal ion, agitation speed, and contact time, were studied for the maximum removal efficiency. Removal efficiency was found to be 62% and 63% for Ni (II) at pH 6.2 in its natural and immobilized forms, respectively. Maximum adsorption occurred within an hour for Ni (II) with JOCN and 90 min for JOCB. The equilibrium data was analyzed using Langmuir and Freundlich isotherms.

Biomass catalytic fast pyrolysis is one of the most promising technologies for the production of renewable aromatics and olefins directly from solid biomass. In this study, catalytic pyrolysis experiments were carried out on biomass in a fluidized bed reactor using typical metal-loaded (Mg, K, Fe, Ga, and Ni) ZSM-5 zeolites as catalysts. The effects of catalysts on the product distribution and bio-oil components were investigated to determine the cheapest and most efficient metal-loaded catalyst. The results showed that bio-oil yields with metal-loaded catalysts (40 to 43.4 wt.%) were a little lower than that of pure ZSM-5 (46.4 wt.%). Metal-loaded catalysts produced more CO2 and CO than did pure ZSM-5. Fe/ZSM-5 produced the highest yield of CO2 (13.8 wt.%), as well as the highest yield of olefins (2.7 wt.%). Fe/ZSM-5 showed the same catalytic characteristics as Ga/ZSM-5 (aromatic hydrocarbon proportion in bio-oils of more than 80%), but it is much cheaper than Ga/ZSM-5.

The pulp yield of orange tree wood was tested under various conditions including processing with soda-anthraquinone (soda-AQ), kraft-anthraquinone (kraft-AQ), or ethanol under different temperature, time, reagent concentration, and PFI laboratory beater beating regimes. Beating grade and stretch properties were studied, with a view to identifying the optimum operating conditions. Polynomial equations were derived that generally reproduced the dependent variables, with errors in most cases much less than 20%. Kraft-AQ pulping was the most efficient. The values of the tensile, burst, and tear indices obtained with kraft-AQ (78.04 Nm/g, 4.84 kN/g, and 2.97 mNm²/g, respectively), were in most cases higher than those found for soda-AQ and ethanol pulps. Using lower values of operational conditions than those required to maximize the studied paper properties (170 °C, 65 min, 13% active alkali, and 2700 number of PFI beating revolutions), it was possible to provide a more energy- and chemically-efficient process for industrial facilities.

Following previous kinetic investigations of the acetylation of cotton linter pulp (Luo et al. 2013), a mathematical model was set up based on the mass and energy balances to simulate the batch acetylation process; a particular goal was to predict the temperature profile. The equations were discretized using a time-dependent finite difference method. The parameters for the model, including the kinetic parameters and heat transfer rate, were well estimated from the literature and our previous work. The model using the least-mean-square-error criterion optimizes the unknown parameters. The proposed model provides an accurate prediction of the process, including the temperature profile, peak temperature, and DS value under the peak temperature. The content of the catalyst, sulfuric acid, has a dramatic effect on the temperature profile. A slight increase in sulfuric acid content will lead to a faster dissolution process for the sulfated cellulose fibers, whereas the reaction rate of the sulfated fibers with acetic anhydride in the liquid phase is not affected. The optimized values of the activation energy are 11.0 and 7.6 kJ/mol for the dissolution processes with low and high sulfuric acid contents, respectively.

Residues of Phyllostachys pubescens bamboo obtained from central Louisiana, USA, were comprehensively investigated for use in liquefaction. The results showed that bamboo branches had the highest Klason lignin and ash content, about 26% and 2.75%, respectively. The epidermis layer sample had relatively higher carbohydrate content, while the wax layer sample had the highest hot water and ethanol-toluene extractives and starch content. The results indicated that the bamboo processing residues showed potential for different chemical feedstocks. No significant differences were found in the infrared spectroscopy (FTIR) spectra of the different samples, indicating that the chemical functional groups were the same, despite variation in chemical components between samples. Klason lignin isolated from the residues showed a higher maximum degradation rate temperature (501 °C) and wider degradation temperature range (200 to 550 °C) than the carbohydrates.

Oil-impregnated insulation paper is widely used in power transformers, and the insulation properties of oil-impregnated insulation paper play an important role in the reliability of power equipment. The formation and dynamics of space charge can affect the performance of insulation material. However, methods to improve the space charge distribution in oil-impregnated insulation paper are rarely reported. In this paper, space charge behavior in oil-impregnated insulation paper has been investigated using the pulsed electro-acoustic (PEA) technique. A series of measurements was applied when the oil-impregnated insulation paper reinforced with different nano-TiO2 contents was subjected to various electric field strengths. The accumulation and decay of space charge are discussed, and the internal electric field strength distribution of oil-impregnated insulation paper is analyzed. The test results show that the space charge distribution is improved and the distortion rate of the internal electric field strength is reduced by adding nano-TiO2 to the oil-impregnated insulation paper. The results show that the proposed method offers a new way to improve the properties of oil-impregnated insulation paper.