Research Articles

The increase of environmental awareness has led to interest in the use of materials with eco-friendly attributes. In this study, a sandwich composite was developed from polyester and kenaf fiber with various orientation arrangements. Polyester/kenaf sandwich composite was fabricated through the combination of a hand lay-up process and cold compression. The tensile, flexural, and Izod impact tests of the sandwich composites were evaluated by using a universal tensile tester and an impact tester. The thermal stability of polyester/kenaf sandwich composite and plywood were investigated by using a thermogravimetric analyser. Results showed that the polyester/kenaf sandwich composite with kenaf fiber in anisotropy orientation achieved the highest mechanical properties. The kenaf fiber in anisotropic orientation could absorb the impact energy and allow the sandwich composite to withstand greater impact forces compared to composite with fiber in perpendicular or isotropic orientations. The polyester/kenaf sandwich composite also showed higher thermal stability compared to a conventional plywood sheet. Thus, the fabrication of polyester/kenaf sandwich composite with kenaf fiber in an anisotropic orientation design has great potential to replace plywood sheets for beam construction applications.

Microalgae have been utilized in wastewater treatment strategies in various contexts. Uncontrolled algal species are a cheap and effective remediation strategy. This study investigates the thermochemical potential of wastewater treatment algae (phycoremediation) as a means to produce renewable fuel streams and bio-products. Three gasification temperature levels were investigated in an auger gasification platform: 760, 860, and 960 °C. Temperature increases resulted in corresponding increases in CO and H2 concentrations in the producer gas from 12.8% and 4.7% at 760 °C to 16.9% and 11.4% at 960 °C, respectively. Condensable yields ranged between 15.0% and 16.6%, whereas char yields fell between 46.0% and 51.0%. The high ash content (40% on a dry basis) was the main cause of the elevated char yields. On the other hand, the relatively high yields of condensables and a high carbon concentration in the char were attributed to the low conversion efficiency in this gasification platform. Combustion kinetics of the raw algae, in a thermogravimetric analyzer, showed three consecutive stages of weight loss: drying, devolatilization, and char oxidation. Increasing the algae gasification temperature led to increases in the temperature of peak char oxidation. Future studies will further investigate improvements to the performance of auger gasification.

An integrated strategy was followed to valorise rice straw, one of the most relevant biomass feedstocks available worldwide, to selectively recover solubilised hemicelluloses and lignin. The pathway encompassed the use of autohydrolysis to hydrolyse the hemicelluloses and an ethanol-based organosolv process to solubilise lignin. Several autohydrolysis conditions were assayed with the best results obtained at 210 ºC (log R0 4.15), which enabled high removal of hemicelluloses, yielding an oligosaccharide-rich hydrolysate and a treated biomass with low content of hemicelluloses and enriched in cellulose and lignin. The effects of ethanol concentration (5 to 75%), and reaction time (0 to 24 h) on lignin removal under mild temperature (30 ºC) were studied. In optimal conditions (60.5% ethanol, 24h) the delignification yield reached 42%, whereas glucan solubilisation was below 17%. Lignin solubilisation yield was not influenced by the organosolv treatment duration while ethanol concentration favored the delignification up to 60.5% ethanol. The organosolv liquors contained economic interesting lignin-derived compounds such as vanillin, ferulic, and coumaric acids. The chemical composition and enzymatic digestibility of the treated biomass from autohydrolysis and organosolv delignification were compared, with the latter presenting an almost 10% higher enzymatic digestibility than the former.

The objective of this research was to evaluate the effect of bamboo species and resin content on the physical and mechanical properties of oriented strand boards (OSBs) prepared from steam-treated bamboo strands. The strands from three species of Indonesian bamboo, namely Andong (Gigantochloa verticillata), Betung (Dendrocalamus asper), and Ampel (Bambusa vulgaris), were steamed at 126 °C for 1 h at a pressure of 0.14 MPa. Three-layered OSBs with the core layer oriented perpendicularly to the face layers were prepared by bonding them together with 3 to 5% methylene diphenyldiisocyanate (MDI) resin based on oven-dried strands and with the addition of 1% paraffin. The strand compositions for the face, core, and back layers were 25%, 50%, and 25%, respectively. The slenderness ratios and aspect ratios of the strands ranged from 71.02 to 76.60 and from 2.96 to 3.02, respectively. The physical and mechanical properties of the OSBs fabricated from Andong and Betung were better than those from Ampel, and the properties of all OSBs were improved by increasing their resin content. OSBs from Betung with 3 to 5% resin content and those from Andong and Ampel with 4 to 5% resin content showed strength retention of more than 50%, which means they can be used for exterior structural applications. Except for OSBs fabricated from Ampel with 3% resin content, the properties of all OSBs prepared in this study were higher than the minimum values required by the CSA O437.0 (grade O-1) standard (2011).

The pulp and paper industry, which is closely related to national economic and social development, is an important industry but also contributes high carbon emissions. Therefore, with the advent of the low-carbon economic era, ways to reduce the carbon emissions and to bring about a low-carbon industrial transition of the pulp and paper industry is becoming one of the important academic projects. A system for carbon footprint assessment, namely the Publicly Available Specification (PAS) 2050 methodology, is introduced in this paper. Based on the analysis and assessment of the carbon footprint (CO2 equivalent emissions) for the Coated Ivory Board production lines, it was used to provide a scientific basis and approach for reduction of carbon emissions and formulate the corresponding measures for carbon emissions reduction of China’s pulp and paper industry. The business to business carbon footprint, for which steps of the life cycle are included in Coated Ivory Board production, was analyzed and calculated. The results showed that there were 888 kg of CO2 equivalent emissions per metric ton of Coated Ivory Board, in which the largest part, accounting for 57.5%, was associated with purchased electricity, followed by fuel oil at 40.2%, and others accounted for 2.3% of the CO2 equivalent emissions.

The experimental research, process design principles, and engineering practice of a bagasse pulp production line that could run both totally chlorine-free (OP)Q(PO) and elemental chlorine-free (OP)D(EOP) bleaching sequences are discussed in this paper. Under specified process conditions, the oxygen delignification rate was up to 50% and the brightness of unbleached pulp increased. The (OP)Q(PO) sequence bleached pulp had a brightness of 83.1% ISO and an intrinsic viscosity of 888 mL/g, and the (OP)D(EOP) sequence bleached pulp had a brightness of 85.7% ISO and an intrinsic viscosity of 905 mL/g. Pulp quality produced from both bleaching sequences was better than pulp bleached by the chlorination, alkaline extraction, and hypochlorite (CEH) sequence. The wastewater was discharged only from the Q or D stage, and the chemical oxygen demand (COD) of Q or D stage was about 650 mg/L or 1100 mg/L, respectively. It was easy to alternate between these two bleaching sequences, and the bleached pulp quality from these sequences was stable.

This paper proposes a method to determine bioethanol concentration that uses a pycnometer verified with a high performance liquid chromatography (HPLC) technique; it is a simple tool to determine the density of liquids for getting information about the ethanol concentration. The results showed that the sugar concentration affected the bioethanol concentration. A lower initial sugar concentration of 26.5 g/L generated higher yield of 45.3% sugar to bioethanol and a fractional or relative yield of 88.74%. Significance tests were used to compare the two experimental means, revealing that the pycnometer method and HPLC provide the same bioethanol concentration with joint variances of 2.269, 0.242, and 0.112 for 3 different tests with initial sugar concentrations of 26.486 g/L, 49.043 g/L, and 68.535 g/L, respectively. This study established and developed a methodology to determine bioethanol concentration from coffee mucilage by the proposed method.

This research provides a novel approach for the determination of water content and higher heating value of pyrolysis oil. Pyrolysis oil from Napier grass was used in this study. Water content was determined with pH adjustment using a Karl Fischer titration unit. An equation for actual water in the oil was developed and used, and the results were compared with the traditional Karl Fischer method. The oil was found to have between 42 and 64% moisture under the same pyrolysis condition depending on the properties of the Napier grass prior to the pyrolysis. The higher heating value of the pyrolysis oil was determined using an oil-diesel mixture, and 20 to 25 wt% of the oil in the mixture gave optimum and stable results. A new model was developed for evaluation of higher heating value of dry pyrolysis oil. The dry oil has higher heating values in the range between 19 and 26 MJ/kg. The developed protocols and equations may serve as a reliable alternative means for establishing the actual water content and the higher heating value of pyrolysis oil.

Birch wood chips were cooked in acetic acid in the presence of phosphinic acid according to the Lignofibre (LGF) organosolv process. The cooking trials were performed according to an experimental design with process time, temperature, and the presence (or absence) of alkaline pre-extraction as the factors. Delignification was enhanced by increased temperature and alkaline pre-extraction. Alkaline extraction also limited xylose hydrolysis, as well as the further degradation of xylose into furfural. Degradation and condensation reactions began to take place between dissolved carbohydrates and lignin at higher temperatures and longer cooking times. Formation of pseudolignin, most likely because of reactions between lignin and furfural, was also observed under the harshest cooking conditions. To avoid these unwanted side-reactions, minimise viscosity losses, and preserve the yield, the LGF process time should be limited to 3 to 4 h at 150 °C.

Moisture adsorption and hygroexpansion behaviors of southern pine (Pinus spp.) treated with 0.5, 1, and 2% concentrations of paraffin wax emulsion were investigated. The specimens, 4 mm along the grain and 20 mm in radial and tangential directions, were exposed to seven different relative humidity conditions of 11, 22, 33, 45, 60, 75, and 92% for adsorption at 30 °C, which was controlled by a self-designed temperature conditioning chamber. Weights and transverse dimensions of the specimens were measured at certain time intervals during the adsorption processes. Results showed that paraffin wax emulsion treatments could reduce both equilibrium moisture content and adsorption rate. Additionally, paraffin wax emulsion treatments also improved dimensional stability, as indicated by estimation of the humidity expansion coefficient (Y) as well as moisture expansion coefficient (X).