Volume 9 Issue 4

In the present work, three different kinds of lignin fractions (L1, L2, and L3) were isolated from the alkali black liquor of Cunninghamia lanceolata by selective precipitation at the pH values of 8 (fraction L1), 5 (fraction L2), and 2 (fraction L3). Elemental analysis, gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FT-IR), 31P nuclear magnetic resonance (31P-NMR), thermal gravimetric analysis (TG), and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) were used to characterize the chemical structure and thermochemical properties of the three lignin fractions. The results showed that L1 presented higher heating value (HHV) and molecular weight compared with L2 and L3. The structures and functional group types were similar for the three lignin grades. However, there was more hydroxyl group in L1 than that in L2 and L3, and the L3 contained a higher amount of carboxylic hydroxyl. L1 exhibited the lowest weight loss value (47.8%) at 200 to 600 oC and the highest amount of charred residue (45.1%), which was exactly the opposite for L3. Phenols, the dominant pyrolysis products, constituted 92.17% of all the pyrolysis products for L1, 93.93% for L2, and 88.09% for L3.

To improve the added value of the lignin products, dimethyl-acetoxy-(2-carboxymethyl ether)-lignin ammonium chloride (DALAC) amphoteric surfactant was synthesized from wheat straw alkali lignin raw material. The structure was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the solubility in different pH solutions was evaluated. The effect of DALAC on adsorption performance was investigated with a solution of copper ions as simulated wastewater, while its flocculation performance was investigated with acid black ATT and methylene blue (MB) wastewater as simulate dyes. The results showed that carboxyl and quaternary amine groups were successfully grafted, and nitrogen content of DALAC was 3.66%. The adsorption isotherm of copper ions with DALAC fit the Freundlich equation. Optimum adsorption conditions for Cu2+ were dosage 0.1 g/L, pH 5.5, and adsorption time 6 h, for which the maximum adsorption capacity was 399 mg/g. The maximum removal rate of Acid black ATT (anionic dye) was 97.8% when the optimum flocculation conditions were dosage 4 g/L, pH 2, and mass concentration of dye 0.1 g/L. The maximum removal rate of methylene blue (cationic dye) was 98.7 %, when the optimum flocculation conditions were dosage 2.5 g/L, pH 9, and mass concentration of dye 0.1 g/L. DALAC will be expected to a novel adsorbent of heavy metal ion and flocculants of dyes in the future.

A lignin-based polymer (GCL1-JB) was dispersed in solvents with different proportion between 1,4 dioxane and water for forming linear and spherical microstructures. The effects of temperature on the solution behaviors and adsorption characteristics of GCL1-JB with different microstructures were investigated by light scattering, conductivity, zeta potential, UV-Vis spectroscopy, atomic force microscopy (AFM), and contact angle measurements. Results showed that GCL1-JB solutions with different microstructures have different responses to environmental temperature changes, which is related to the movements of charges. For GCL1-JB with a spherical microstructure, as the temperature increases, the degree of ionization does not decrease. However, the surface charges decrease due to the charged groups moving from the surface into the interior because of the charge gradient, which induces a significant decrease in the zeta potential. As the surface charges decrease and the hydrophobic interaction increases, the GCL1-JB aggregates. Therefore, the scattered light intensity increases significantly and the corresponding GCL1-JB adsorbed film has a larger adsorbed amount, a more rough surface , and a larger contact angle. However, for GCL1-JB with a linear microstructure, the surface charges do not obviously change with a temperature increase, even though the charged groups move from side to side. Therefore, the zeta potential and the scattered light intensities of these GCL1-JB solutions are basically independent of temperature, and the corresponding adsorption characteristics do not obviously change.

Efficient utilization of biomass resources is crucial for providing renewable energy and mitigating the risk of environmental pollution caused by crop straw burning in China. Straw ring-die briquetting forming is a convenient densification technology to make the low density biomass into briquette fuel; however, the energy consumption of this process is still a challenge. Productivity and torque modeling were carried out in this study on the basis of theoretical derivation. Generally, the straw briquetting process is divided into a compression deformation stage and an extrusion forming stage with the die structure (ring die and roller radius ratio λ) and friction angle φ being the main factors that affect the productivity. Mechanical modeling based on material compaction and calculation modeling based on die-hole pressure were considered for the calculation of σαx in the torque model. A calculation case was then conducted according to the theoretical model, and actual productivity and torque testing were performed for validation purposes. Results show that this deduced productivity model is successful because the deviation is 4.61%. The torque model determined by the calculation model based on die-hole pressure had a better accuracy with a deviation of 6.76%.

This study concerns the influence of selected fungi on changes in physical and mechanical properties of type P2 particleboards intended for use in dry conditions. The tested fungi included Aspergillus niger van Tiehgem, Chaetomium globosum Kunze et Fr., Trichoderma viride Persoonex S.F., Gray aggr., and Penicillium funiculosum Thom. The incubation process lasted for 16 weeks, yet samples for the strength test were selected after a period of four weeks. The degradation level of boards was estimated by measuring the decrement of initial mass and changes in physicomechanical properties. The obtained results showed that mechanical strength of the investigated boards affected by the tested fungi decreased by 15% to 20%. However, the differences in DSC thermographs indicate that it is cellulose that mainly undergoes degradation in the wood of the investigated boards. Based on the changes in mechanical properties and DSC analyses, we consider T. viride and A. niger as the most aggressive fungal species.

The objective of this study was to investigate the effects of panel type and panel thickness on moment resistance of L-type corner joints and deflection characteristics of four-member cabinets. Three different wood based panels, namely particleboard (PB), medium density fiberboard (MDF), and okoume (Aucoumea klaineana) plywood (PW) were utilized in two different thickness levels for constructing the four-member cabinets. All corner joints and cases were assembled with 4 x 50 mm screws without adhesive. The four member cabinets were tested under static load by supporting at three points. Furthermore, moment resistances of the same type jointed L-type corner joints were tested under static compression and tension loads. Test results indicated that the highest stiffness values were observed with 15 mm PW. This showed that 15 mm plywood could be used instead of 18 mm PW. 16 mm PB and MDF cabinets yielded higher stiffness values than those of 18 mm MDF, PW, and PB. Test results also indicated that 15 mm and 16 mm thick panels can have nearly the same stiffness as 18 mm thick panel.

Wood vinegar (WV) was obtained from charcoal production byproducts. The increase in demand for WV as an alternative pesticide requires more production of WV independent of conventional charcoal production. This research was intended to commence the production of WV from available furniture wood waste. The study included the following: (i) the preparation and performance of a pyrolysis kiln; and (ii) the application of the produced WV as a plant growth regulator of papaya plants in the nursery and as a pest insect repellent during maize storage. These experiments were arranged in a randomized block design. The observed variables included pyrolysis rate, the effect of WV on papaya growth in nursery, and the effect of WV in controlling infestation of maize weevils. The data were analyzed using analysis of variance and continued with Duncan’s multiple difference test. The results showed that while the production of WV continuously occurred until the 90th min, the maximum (139 mL) was reached at the 10th min. Pyrolysis of 1,000 g of chips of wood-planer’s waste yielded WV, tar, bio-oil, and char in quantities of 487.67 mL, 41.76 g, 2.93 mL, and 222 g respectively. The treatment using WV (50 mL/L) increased the diameter of papaya stems in the nursery. Mixing and fuming application of 5 mL of WV as a pest insect repellent on 200 g of maize on the storage could increase the number of the dead maize weevil and reduce the damage maize kernel.

A characterization study on oil palm decanter cakes (OPDC) was performed to gain an in-depth understanding of the material’s characteristics to aid in potential residual oil recovery. The OPDC was characterized by a high moisture content, high biodegradability, high organic content, and a nutrient-rich composition. Microscopic observation showed that the oil attachments in OPDC, and a vast majority of the droplets, were less than 50 μm in size. Furthermore, contact angle measurement revealed the hydrophilic and oleophilic characteristics of OPDC. Specifically, the contact angles of water and crude palm oil (CPO) with OPDC were both less than 45° with absorption rates of 0.0265 ± 0.003 µL/s and 0.1042 ± 0.05 µL/s, respectively. The OPDC is a fibrous material, and the surface area and pore size measured were 7.103 m2/g and 481.7 Å, respectively. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric (TG) analysis results showed the functional groups and degradation properties of OPDC, respectively.

The effects of chlorite bleaching on the properties of cellulose derived from oil palm empty fruit bunch (OPEFB) fiber were investigated in this work. Cellulose was extracted from oil palm empty fruit bunch fiber via chlorite bleaching, alkali treatment, and acid hydrolysis. Cellulose was extracted by varying the bleaching duration, which corresponded to 4, 8, or 12 h. Fourier transform infrared (FTIR) analysis showed that the lignin and hemicellulose were significant removed after the bleaching process, whereas no spectral differences were observed in the samples with the increase of bleaching durations. The main removal of the lignin and hemicellulose components had occurred during the bleaching process. There was only slight additional removal of lignin and hemicellulose during the further extraction process with alkali and acid hydrolysis. The peaks at 1740 cm^-1 and 1246 cm^-1 which represent hemicellulose and lignin, respectively, were not present in the final extracted cellulose.The cellulose yield contents did not increase with the increasing of bleaching duration from 4 h to 12 h. X-ray diffraction (XRD) analysis revealed that the crystallinity and the 200 peak of OPEFB had increased after the bleaching process. Analysis of the visible light transmittance of cellulose, after a bleaching duration of 12 h, demonstrated the highest transmittance due to the disintegration of the fibers. By increasing the bleaching duration, the temperature at 50% weight loss of OPEFB increased, suggesting that the thermal stability of cellulose had improved.

Wood pulp waste is a type of industrial waste that has an enormous potential for fermentable sugar production. Efficient pretreatment is the key for enhancing the enzymatic efficiency. In this paper, sodium hydrogen sulfite pretreatment was performed on wood pulp waste to improve enzyme performance through sulfonation and hydrolysis reactions. Results showed that the enzymatic efficiency was greatly enhanced from 5.12 to 41.6% in terms of reducing sugar yield (RSY) under the optimum conditions: 6% NaHSO3, 2500 P-factor, 3/1 liquid to solid ratio, and cellulase charge of 35 FPU/g substrate. Mass balance showed that approximately 73% of glucose was recovered. The mechanism of sulfonation and hydrolysis of sodium hydrogen sulfite pretreatment were confirmed by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (X-RD), and scanning electron microscopy (SEM).