Volume 9 Issue 4

Green liquor pretreatments and different liquid-fermentation strategies were tested to establish an effective ethanol production process from corn stover. After pretreatment and enzymatic hydrolysis, 329.7 g of glucose and 126.3 g of xylose were obtained from 1,000 g of dry corn stover. The primary aim of this work was to test the fermentability of the enzymatic hydrolysate of green liquor-pretreated corn stover, for no fermentation has been done on the enzymatic hydrolysate of green liquor-pretreated corn stover before. Three liquid-fermentation strategies, including sequential fermentation, co-fermentation, and co-culture, were carried out and compared to select an appropriate fermentation strategy from green liquor-pretreated corn stover. Among the different liquid-fermentation strategies, sequential fermentation yielded the highest ethanol production (210.7 g ethanol/1,000 g corn stover). Using the sequential fermentation strategy, glucose fermentation by Saccharomyces cerevisiae and ethanol distillation was completed prior to xylose fermentation by Pichia stipitis, so that the separate utilization of glucose and xylose ensured that each fermentation stage used the suitable microorganism, permitting high ethanol yields. Sequential fermentation was thus considered to be the most promising liquid-fermentation strategy for ethanol production from green liquor-pretreated corn stover.

Biochar (BC) produced from brewer’s spent grain (BSG) via slow pyrolysis at 300, 400, 500, 600, and 700 °C was characterized and investigated as an adsorbent for the removal of the pesticide pymetrozine from aqueous solution. Batch BSG BCs adsorption experiments were carried out under various conditions (such as pH, pymetrozine concentration, and BC dosage) to adsorb the pymetrozine. The BSG BCs adsorption pymetrozine capacities were increased by 21.4% to 55.5% under pyrolysis temperatures of 300, 400, 500, and 600 °C compared to 700 °C with a pyrolysis time of 2 h and by 19.0% to 52.1% at 4 h. At solution pH values of 2, 4, 6, and 8, the adsorption capacities were increased by 9.6% to 39.5% compared with that at pH 10. A similar adsorption tendency was found for the different BCs dosage. In the first 60 min, BC absorbed 70% to 80% pymetrozine. The Langmuir and Freundlich model were highly correlated with BC adsorption. The magnitude of free energy decreased by 32.2% to 47.3% with increasing temperature. The value of the enthalpy change showed the adsorption to be endothermic. The BSG BC had high efficiency in adsorbing pymetrozine and had great potential to prevent the water pollution and reuse the waste of the beer factory.

Bamboo fiber was treated using a high-pressure enzyme hydrolysis process. The process performance was compared with the pulping and bleaching process for bamboo fiber. Several analytical methods, including field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetry, and differential scanning calorimetry, were employed to determine the physicochemical and thermal properties of the treated cellulosic bamboo fiber. It was found that the pressurized enzyme hydrolysis treated bamboo fiber had the most uniform morphological structure, along with lowest crystallinity and highest thermal stability. Thus, utilizing high-pressure enzyme hydrolysis is the most effective process for treating fiber to remove non-cellulosic components from the raw material, including lignin, hemicelluloses, and waxy materials.

This study aims to determine the properties of waste betel nut husk (BNH) fiber as a potential alternative for reinforcement in polymer composites. The BNH fibres were subjected to alkali treatment using 5% sodium hydroxide. In this work, husk fibres extracted from betel nut fruit were characterized for its chemical composition, tensile properties, morphology, and interfacial shear strength. The cellulose content was increased with alkali treatment. Tensile strength and Young’s modulus of BNH fibre dropped drastically with alkali treatment but with improvement in elongation at break of the fibre due to extraction of cementing materials of microfibrils in natural fibre, i.e. lignin and hemicellulose. SEM observations revealed that poor tensile strength and modulus were related to the cell wall thinning and deep pores in BNH fibre due to alkali treatment. Interfacial shear strength (IFSS) of alkali treated fibre was higher as compared to untreated BNH fibre due to the increase in fibre surface roughness with alkali treatment.

The objective of this study was to determine the design value for the compressive strength (CS) for bamboo fiber-reinforced composite (BFRC) based on a reliability analysis. A total of 180 specimens were subjected to static compressive testing. The CS of the BFRC was significantly higher than that of raw bamboo and other bamboo-based composites, and its cumulative probability distribution accorded with a normal distribution. Furthermore, a calculation program of the reliability index (β) was developed by adopting the first-order second-moment method. Results of the reliability analysis indicate that β increases nonlinearly not only with the enhancement of the partial coefficient but also with the live-to-dead load ratio in all the simulation load cases. The simulation load case of the maximum and minimum β is G+LO and G+LS, respectively. To meet the target reliability requirement, it is suggested that the design value of CS for BFRC be 43.247 MPa and the partial coefficient be 2.0.

Agricultural residues represent a disposal problem and a biomass source for chemical production. Lignocellulosic composition varies in plants as a function of several factors such as physiological age and tissue function. Banana pseudostem is a large biomass resource that is usually wasted, in spite of the possibility that it can be used as a source of organic compounds such as cellulose and hemicelluloses. The aim of this paper is compare the lignocellulosic content and physicochemical properties of different sheaths of Pacovan banana pseudostems. The trunk was divided into four different fractions, from the outermost sheaths to the core of the structure. There was a significant difference between the lignocellulosic compositions of the fractions. The X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry measurements reflected this difference in the sheaths. These results indicate that the Pacovan banana pseudostem cannot be considered to be a uniform biomass, and future approaches to its use as a biorefinery feedstock must consider a preliminary separation of the sheaths prior to chemical extraction of organic components.

Three types of biomasses (miscanthus, spruce, and a mixture of different woodchips species) were tested as low-cost adsorption media for an industrial agro-industrial effluent, typically a vinasse. Influences of effluent dilution, working temperature, and time duration were studied. Kinetic modelling studies of adsorption were proposed. Ratios of adsorption at ambient temperature and without dilution expressed in g of dry vinasse per g of dry biomass were 1.0, 0.85, and 0.65 for miscanthus, woodchips mixture, and spruce, respectively. An increase of the temperature from 10 °C to 50 °C led to a decrease of the vinasse viscosity and favored its penetration in the biomasses. Maximal adsorbance of dry matter of vinasse was obtained at 50 °C for a vinasse viscosity of 20 mPas. Whatever the experimental conditions required during adsorption processes, miscanthus showed the best affinity for the vinasse. Pseudo-second order and intra-particle diffusion model well described the adsorption process. This study indicates that conventional biomasses could be used as natural low-cost adsorbent for by-products such as vinasse.

Dissolved petroleum-based compounds, e.g. solvents, pesticides, and chemical reagents such as phenolic compounds, can pose significant hazards to the health of humans and ecosystems when they are released to the environment. This review article considers research progress related to the biosorption and removal of such contaminants from water using cellulose-derived materials. The fact that cellulosic materials show promise in removing such sparingly soluble materials from water lends support to a hypothesis that lignocellulosic materials can be broad-spectrum adsorbents. Also, the hydrophobic character and sorption capabilities can be increased through thermal treatment and the preparation of activated carbons. As shown in many studies, the efficiency of uptake of various petrochemical products from water also can be increased by chemical treatments of the adsorbent. It appears that more widespread adoption of biosorption as a means of removing petroleum-based products from water has been limited by concerns about the used, loaded biosorbent. Disposal or regeneration options that need to be considered more in future research include enzymatic and biological treatments, taking advantage of the fact that the biosorbent material is able to collect, immobilize, and concentrate various contaminants in forms that are suited for a number of packed bed or batch-type degradative treatment systems.

Oil palm (Elaeis guineensis) ash is defined as the waste generated after the combustion of oil palm biomass. Malaysia is one of the world’s largest producers and exporter of palm oil in the world, and there is approximately 4 million tonnes of oil palm ash generated annually. It is estimated that the amount of oil palm ash will keep increasing due to the high demand for palm oil globally. Normally, oil palm ash is disposed without any beneficial economic return value. The awareness of this environmental crisis has increased significantly over the past few years. With the evolution of ash utilization strategies, interest in oil palm ash in various research fields has grown. Through the effort of researchers and information available, the properties of the resulting materials are affected by the percentage of substitution and particle size of the oil palm ash. The major challenges in utilizing oil palm ash are discussed in this paper, as are the beneficial effects, which can include reducing the negative environmental impact and the product cost. Although the recycling of oil palm ash is still a new focus of interest, the main thrust of waste management in Malaysia will continue to focus on this kind of research and will attempt to solve the problem of disposal of the ash as well.

Wood-based composites are widely used in consumer products, either in structural or non-structural applications. One of the basic elements for wood-based composites is the binder itself. Recent years have seen great development and trends in the field of eco-friendly binders in wood-based composite. There have been many concerns on the effects of formaldehyde and volatile organic compounds (VOC) released from wood-based products. Researchers have put lot of effort into developing environmental friendly products with enhanced sustainability. Binder materials with a focus on geopolymers (i.e., alumino-silicates) are discussed in this publication. The development and utilization of geopolymeric binders is relatively new in the field of wood-based composites. Up to the present there has been insufficient information regarding the manufacturing conditions and properties of wood-nonwood composite materials prepared using a geopolymeric binder. This paper considers the background of geopolymer materials and the possibilities of producing inorganic-bonded wood composite using geopolymer.