Volume 10 Issue 4

The production of palm oil requires a large amount of water, which subsequently turns into wastewater known as palm oil mill effluent (POME). Because of its high organic content, there has been debate over how to utilize POME for oil recovery. POME is usually mainly comprised of water (95 to 96%), total solids (4 to 5%), suspended solids (2 to 4%), and oil (0.6 to 0.7%). The lignocellulosic particles in POME are highly oleophilic and capable of absorbing oil. Therefore, the objective of this study was to understand the presence of residual oil and try to relate with the oil loss in POME and to identify the solid particles in POME and their correlations. Microscopic observations showed that most of the oil droplets available in POME were less than 100 µm in size. If given the opportunity to settle, the highest quantity of oil droplets and solid particles was in the bottom layer, followed by the middle layer, and lastly the upper layer. In cases where the contact angle of water was less than 45° on POME solids, the absorption rate was 0.11 ± 0.03 µL/s and 0.09 ± 0.01 µL/s, respectively. This study concluded that the oil losses in POME were partly due to the absorption of oil by the fibers.

Original data for mass, element, and methane dynamics under controlled pyrolysis are presented for several biomass feedstocks. The experimental system consisted of an environmental (low-vacuum) scanning electron microscopy (ESEM) with a hot-stage and energy-dispersive X-ray spectroscopy (EDS) detector. A tunable diode laser (TDL) was coupled to the ESEM vacuum pump to measure the methane partial pressure in the exhaust gases. Thermogravimetric analysis and differential thermal analysis (TG/DTA) in a N2 atmosphere was also carried out to assess the thermal properties of each biomass. It was found that biochars were depleted or enriched in specific elements, with distinct methane formation change. Results depended on the nature of the biomass, in particular the relative proportion of lignocellulosic materials, complex organic compounds, and ash. As final temperature was increased, N generally decreased by 30 to 100%, C increased by 20 to 50% for biomass rich in lignocellulose, and P, Mg, and Ca increased for ash-rich biomass. Methane formation also allows discriminating structural composition, providing fingerprints of each biomass. Biomass with low ashes and high lignin contents peaks CH4 production at 330 and 460 °C, whereas those biomasses with high ashes and low lignin peaks CH4 production at 330 and/or 400 °C.

This article focuses on the plane milling of thermally modified birch wood while taking into account technological parameters that have substantial effects on the processed wood surface’s average waviness profile deviation (Wa). The milling process was affected by the cutting speed, which varied from 20 to 60 m/s, with a feed rate of 4, 8, and 11 m/min. The results obtained on the set of thermally modified test specimens, were compared with the results obtained on test specimens without heat treatment. The surface finish was measured using various milling parameters. The material removal was 1 mm per pass. The results indicate that the thermal processing of wood did not significantly influence the arithmetic average deviation of the roughness profile (Ra). Cutting speed and feed rate had the most significant effects among the monitored factors. The lowest arithmetic average deviation of the roughness profile (Ra) was determined at a feed rate of 4 m/min and cutting speed of 40 m/s. An increase in cutting speed led to a decrease in the average roughness, while increased feed rate had the opposite effect.

Nanocellulose was successfully prepared from microcrystalline cellulose (MCC) via nickel salt-catalyzed hydrolysis under mild reaction conditions of 45 °C for 15 min. The mild acid nickel salt-catalyzed hydrolysis was able to selectively depolymerize the amorphous regions of cellulose and retain its crystalline region, thus improving the crystallinity of the treated product at the nanoscale up to 80%. FTIR analysis confirmed that the basic cellulose structure of inorganic metal salt-treated products was maintained and that no derivative was formed. Furthermore, the synthesized Ni-treated nanocellulose (NTC) products appeared in the form of cluster fragments with spider-web-like appearance (fiber diameter of 10 to 60 nm and fiber length of 300 to 600 nm), thus providing aspect ratios in the range of 7.96 to 9.11. In addition, NTC products exhibited relatively higher thermal stability as compared to MCC because of the presence of high crystallinity phases and the absence of impurities (such as nitrate ions) on the nanocellulose surface. Thus, the present study concluded that nickel-based inorganic salt is an efficient and selective catalyst for the hydrolysis of MCC with high simplicity in operation and short preparation time.

To increase understanding of breakdown strategies for Mozambican timber, simulations were carried out using different sawing patterns that can be alternatives to the low degree of refinement performed for export today. For the simulations, 3D models of 10 Jambirre and 5 Umbila logs were used. The log shape was described as a point cloud and was acquired by 3D-laser scanning of real logs. Three sawing patterns (cant-sawing, through-and-through sawing, and square-sawing) were studied in combination with the log positioning variables skew and rotation. The results showed that both positioning and choice of sawing pattern had a great influence on the volume yield. The results also showed that the log grade had an impact on the sawing pattern that should be used for a high volume yield. The volume yield could be increased by 3 percentage points by choosing alternative sawing patterns for fairly straight logs and by 6 percentage points for crooked logs, compared to the worst choice of sawing pattern.

Modified starch was prepared in this work by acid-thinning and oxidizing corn starch with ammonium persulfate. Also, starch-based aqueous polymer isocyanate (API) wood adhesive was prepared. The effect of the added amount of modified starch, styrene butadiene rubber (SBR), polymeric diphenylmethane diisocyanate (P-MDI), and the mass concentration of polyvinyl alcohol (PVOH) on the bonding strength of starch-based API adhesives were determined by orthogonal testing. The starch-based API adhesive performance was found to be the best when the addition of modified starch (mass concentration 35%) was 45 g, the amount of SBR was 3%, the PVOH mass concentration was 10%, and the amount of P-MDI was 18%. The compression shearing of glulam produced by starch-based API adhesive reached bonding performance indicators of I type adhesive. A scanning electron microscope (SEM) was used to analyze the changes in micro-morphology of the starch surface during each stage. Fourier transform infrared spectroscopy (FT-IR) was used to study the changes in absorption peaks and functional groups from starch to starch-based API adhesives. The results showed that during starch-based API adhesive synthesis, corn starch surface was differently changed and it gradually reacted with other materials.

Co-pyrolysis of Shenmu coal (SM) and cotton stalk (CS) at different blend ratios were carried out in a tubular furnace. The pyrolysis temperature was up to 600 °C at 5 °C/min and kept for 15 min. The results indicated that there was an interactive effect between SM and CS, which increased the tar yield. Moreover, the content of light components in co-pyrolysis tar from all CS/SM blend ratios was higher than that in the tar derived from SM pyrolysis. This interaction not only increased tar yields but also upgraded the quality of tar in the co-pyrolysis process. Compared with the co-pyrolysis of de-ashed CS and SM, the inherent minerals of CS had great effects on the co-pyrolysis tar yield. The analysis results of n-hexane soluble extracted from co-pyrolysis tar by gas chromatography/mass spectrometry indicated that the organic matters of CS had a significant effect on the alkene formation of tar during co-pyrolysis. The maximal tar yield was 13.73 wt% (daf) and the yield of n-hexane soluble reached 11.13 wt% (daf) under optimum conditions.

To apply bacterial cellulases for efficient saccharification of biomass, three Clostridium thermocellum cellulases and a Thermoanaerobacter brockii β-1,4-glucosidase were synthesized in Escherichia coli, and the proportions among them were optimized. When the activities of CelD, CBHA, CBH48Y, and CglT were set at 554, 0.91, 0.91, and 856 mU per assay, respectively, the percent conversion of regenerated cellulose (0.92 g/L) reached 80.9% within 24 h at 60 °C without shaking. Meanwhile, the percent conversion of pretreated corn stover (0.62 g/L) reached 70.1%. Gradually raising the loads of regenerated cellulose from 0.92 to 4.58 g/L resulted in a linear increase in glucose production from 870 to 3208 μg (R2=0.997), as well as a decrease in the percent conversion from 80.9% to 59.6%. These findings suggested that the cellulase cocktail is efficient in saccharification of regenerated cellulose, as well as pretreated corn stover, and has potential applications in the biofuels industry.

To improve the performance of polyvinyl chloride (PVC), composites incorporating polyvinyl chloride (PVC), attapulgite nanoparticles (ANPs), and microcrystalline cellulose (MCC) were successfully prepared. The composites had higher vicat softening temperatures (VSTs) and the MCC had a great influence on mechanical properties of the composites. When MCC was added from 0 to 5 per hundred parts of PVC (phr), the mechanical properties of the composites increased, but the mechanical properties of the composites decreased when the MCC was more than 5 phr. The tensile breaking stress, tensile strength, and impact strength were maximized with increases of 19.76 N (4.1%), 29.66 MPa (15.5%), and 13.8 MPa (7%) when 5 phr MCC was added. Infrared spectral analysis indicated that MCC and ANPs were present in the composites. Scanning electron microscopy showed that the composites system was distributed into two phases, which indicated that MCC in composites was dissolved in the PVC matrix, and some of MCC coated the surface of ANPs as a compatibilizer. Overall, this study provided a promising method for PVC modification to improve its performance.

The desilication effects of aluminium sulphate and sodium aluminate on kraft bamboo pulp during the cooking process were investigated in this study. Furthermore, the residual aluminium ion concentration in the resulting black liquor was measured by inductively coupled plasma atomic emission spectrometry (ICP-AES) to evaluate the scaling properties of black liquor during the evaporation process. Atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM-EDS) analysis showed that aluminium salts could react with silica to form a silica-alumina compound, which can adhere to the fibre surface during the cooking process. As a result, the silicon content in the black liquor could be effectively decreased by the addition of aluminium sulphate and sodium aluminate. A silica removal ratio of 74% could be achieved when the loadings of aluminium sulphate and sodium aluminate were 2.0 wt.% and 1.5 wt.%, respectively. Finally, the concentration of aluminium ions was 7.31 ppm under optimised conditions. Based on these considerations, any amounts of aluminum ion passing into the black liquor are unlikely to contribute to scaling problems.