Volume 11 Issue 2

Nano-cellulose was prepared via acid hydrolysis and cell crushing using microcrystalline cellulose as the raw material. Mesoporous TiO2 was then prepared via hydrothermal synthesis using butyl titanate as the titanium source and the previously prepared nano-cellulose as the template. It is confirmed by FT-IR and XRD that the commercial product P25 consisted of anatase and rutile mixed crystal structure, in which the content of anatase and rutile was 80.5% and 19.5%, respectively. The prepared TiO2 had an anatase single crystal structure. XPS analysis showed an elemental content of C, O, and Ti with two kinds of TiO2. TEM, HRTEM, and electron diffraction were used to characterize the particle size of the prepared mesoporous TiO2, mainly concentrated in the 10 to 20 nm range. Crystalline spacing was 0.35 nm (101). By comparison, the particle size of P25 was mainly distributed in the 15 to 25 nm range with a crystalline spacing of 0.35 (101) and 0.32 nm (110) respectively. XRD analysis was consistent with the results. Based on N2 adsorption-desorption isotherm curves it was evident that the surface area of prepared TiO2 and P25 was 38.92 m2/g and 53.54 m2/g, the cumulative pore volume of the two is 0.24 m2/g and 0.17 m2/g respectively. The experiments of photocatalytic degradation of rhodamine B showed that the catalytic ability of the prepared mesoporous TiO2 to degrade pollutants was better than commercial TiO2 under UV irradiation.

A novel sulfonated bamboo-derived carbon (SBC) was prepared through a one-pot simultaneous carbonization and sulfonation method using p-toluenesulfonic acid as the sulfonating agent. This method was used in place of the two-step method of high temperature carbonization followed by sulfonation, in order to reduce energy consumption and avoid the use of substantial amounts of strong liquid acid. The as-prepared catalyst bearing SO3H, COOH, and phenolic OH groups demonstrated efficient catalytic activity in the dehydration of fructose to 5-hydroxymethylfurfural (HMF), achieving 92.1% HMF yield in a mixture of tetrahydrofuran (THF) and dimethylsulfoxiden (DMSO) (volume ratio of THF/DMSO 3/7). The mixture had a fructose concentration of 0.08 g·mL-1 with a catalyst amount of 10% weight of fructose at 140 °C in 60 min. No distinct activity drop was observed after the initial deactivation during 5 recycling runs, confirming a good stability of the prepared catalyst. Moreover, kinetic data showed that SBC promoted fructose dehydration to HMF may follow pseudo-first order kinetics with the activation energy of 43.6 kJ·mol-1 under investigated conditions. The convenient catalyst preparation method and excellent catalytic performance of the catalyst provide an easy-handling and eco-friendly strategy for crude biomass utilization in catalyst production.

To investigate the effects on moisture sorption behavior of wood caused by the removal of chemical components, Populus euramericana flour (40 to 60 mesh) was divided into four groups: untreated, extractives removed, hemicellulose removed, and matrix removed. The samples at the fiber saturation point and under oven-dried conditions were separately exposed to relative humidities of 11%, 45%, and 75% at 25 °C for desorption and adsorption. Additionally, moisture changes were measured during the processes. The results showed that moisture changed rapidly for all four groups at the initial stage during sorption, after which the rate gradually decreased until a steady-state equilibrium was reached. Among the four groups, the samples from which extractives had been removed exhibited the highest moisture content and moisture sorption coefficient, followed by the untreated samples, hemicellulose removed, and matrix removed samples. With increasing relative humidity, the hysteresis ratio A/D of the samples increased, indicating a reduction in sorption hysteresis, which was further decreased by hemicellulose extraction.

Understanding employment trends is important for discerning the economic vitality of U.S. hardwood lumber users. After a period of growth in the 1990s, employment in industries consuming hardwood lumber has declined in the 21st century. The wood household furniture industry has experienced the greatest decline, with North Carolina, Virginia, and California being the states most affected. Nearly all of the decline in employment in the furniture industry can be attributed to increased importation of this product. Millwork and kitchen cabinets are industries associated with home construction. Both of these industries experienced declines in employment in the 21st century. Employment in millwork started to decline after 2000, while employment in the kitchen cabinet industry started to decline after 2006. While there was little change in the relative regional employment rankings in the millwork industry, Indiana displaced California and Texas to become the largest employer in the kitchen cabinet industry. Employment in the pallet industry has declined in the 21st century, but mostly during the two recessionary periods. The pallet industry was the only industry that had an employment increase after 2009. Ohio was once the major pallet producing state, but it was displaced by California and Texas after 2002.

Sulphate removal from mine water is a problem because traditional chemical precipitation does not remove all sulphates. In addition, it creates lime sediment as a secondary waste. Therefore, an inexpensive and environmental-friendly sulphate removal method is needed in addition to precipitation. In this study, carbon residues from a wood gasification process were repurposed as precursors to a suitable sorbent for SO42- ion removal. The raw material was modified using ZnCl2, BaCl2, CaCl2, FeCl3, or FeCl2. Carbon residues modified with FeCl3 were selected for further consideration because the removal efficiency toward sulphate was the highest. Batch sorption experiments were performed to evaluate the effects of the initial pH, initial SO42- ion concentration, and contact time on sulphate removal. The removal of SO42- ions using Fe-modified carbon residue was notably higher compared with unmodified carbon residue and commercially available activated carbon. The sorption data exhibited pseudo-second-order kinetics. The isotherm analysis indicated that the sorption data of Fe-modified carbon residues can be represented by the bi-Langmuir isotherm model.

This study investigated the effect of heat-treated wood content on the water absorption, mechanical, and thermal properties of wood plastic composites (WPCs). The WPCs were produced from various loadings (30, 40, and 50 wt%) of heat-treated and untreated alder wood flours (Alnus glutinosa L.) using high-density polyethylene (HDPE) with 3 wt% maleated polyethylene (MAPE) coupling agent. All WPC formulations were compression molded into a hot press for 3 min at 170 ºC. The WPCs were evaluated using mechanical testing, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The mechanical property values of the WPC specimens decreased with increasing amounts of the heat-treated wood flour, except for the tensile modulus values. The heat treatment of alder wood slightly increased the thermal stability of the WPCs compared with the reference WPCs. The crystallization degree (Xc) and the enthalpy of crystallization of the WPCs slightly decreased with increasing content of the heat-treated wood flour. However, all WPCs containing the heat-treated alder wood flour showed a higher crystallinity degree than that of the virgin HDPE.

A 56-kDa β-glucosidase (TthBgl) derived from Thermotoga thermarum DSM 5069 was expressed and purified from Escherichia coli BL21 (DE3). The purified enzyme showed hydrolytic activity towards only p-nitrophenyl-β-D-glucopyranoside among the synthetic glycosides tested. The pH maximum was 5.0, and under the conditions tested, maximal activity was at 85 ºC, and pH stability occurred from 5.0 to 6.0. After being incubated at 80 ºC for 120 min, TthBgl retained 80% of its original activity. The β-glucosidase had no apparent requirement for metal ions or other co-factors, but its activity was significantly inhibited by 0.1% SDS and 1mM Cu2+, in which only 3% and 10% residual activity was maintained, respectively. The Vmax of TthBgl was 8.79 U mg-1 for p-nitrophenyl-β-D-glucopyranoside, while the Km was 2.41 mM. The Enzyme activity was gradually inhibited by the addition of glucose, but remained approximately 50% of its original value in 500 mM glucose. 789.25 mg/L glucose was released from cellobiose by the incubation of 0.2 U/mL TthBgl for 9 h at 75 ºC. According to a phylogenetic analysis, TthBgl belongs to the glycosyl hydrolase family 3 (GH3).

In this study, activated carbon fibers (ACFs) were prepared from liquefied wood by chemical activation with ZnCl2, with a particular focus on the effects of temperature and ZnCl2: liquefied wood-based fiber (LWF) ratio on yield, porous texture, and surface chemistry. The characterization and properties of these ACFs were investigated by nitrogen adsorption/desorption, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). When using a 6:1 impregnation ratio, the specific surface area (SBET) of the resultant ACFs was as high as 1423 m2/g. The effect of an increase in impregnation ratio on the porosity of ACFs was stronger than that of an increase in the activation temperature. However, the former had a weaker impact on the surface chemistry and structure. It was also found that the yields of ACFs obtained by ZnCl2 activation were higher than those obtained by physical activation. Besides, the prepared ACFs presented higher adsorption than other raw materials in the adsorption test, indicating that ACFs prepared from LWF by ZnCl2 activation could be used as an adsorbent for the adsorption of medium size organic compounds.

Sugarcane bagasse was pretreated by green liquor combined with ethanol (GL-Ethanol) and green liquor combined with H2O2 (GL-H2O2). After 72 h of enzymatic hydrolysis, the glucose yields of sugarcane bagasse pretreated with GL-Ethanol and GL-H2O2 were 97.7% and 41.7%, respectively. The reason that GL-Ethanol was more effective than GL-H2O2 has not been elucidated clearly. In this study, the chemical composition of the sugarcane bagasse and chemical structure of the isolated lignins after these two pretreatment methods were characterized to investigate their correlation with the enzymatic hydrolysis of sugarcane bagasse. The removal of lignins with GL-Ethanol pretreatment was much higher than that of GL-H2O2. In addition, the decomposition of cellulose was lower in the case of GL-Ethanol than in that of GL-H2O2. According to Fourier transform infrared spectroscopy (FT-IR) and 1H-nuclear magnetic resonance (NMR) studies, the ester bonds (belonging to lignin-carbohydrate complex) could be broken during GL-Ethanol treatment. It was also found that the molecular weight of lignins obtained from GL-Ethanol was lower than that of lignins from GL-H2O2.

Xylanase pretreatment was used to improve the chlorine dioxide bleaching of bagasse pulp. The pulp was pretreated with xylanase, which was followed by a chlorine dioxide bleaching stage. The HexA content of the pulp and the AOX content of the bleaching effluent were measured using UV-Vis and GC-MS methods, respectively. The results showed that a good correlation occurred between HexA and kappa number. HexA content of the pulp decreased significantly after the xylanase pretreatment. The AOX content of the bleaching effluent decreased as HexA was removed from the pulp. It was found that AOX could be reduced by up to 29.8%, comparing XD0 with a D0 stage. Fourier transform infrared spectroscopy (FTIR) was employed to determine the breakage of chemical bonds in the pulp. It revealed that some lignin and hemicellulose were removed after xylanase treatment. The GC-MS results showed that some toxic chloride such as 2,4,6-trichlorophenol could be completely removed after xylanase pretreatment.