Volume 14 Issue 4

Bio-oil upgrading via microwave-assisted pyrolysis of corncob over CaO and HZSM-5 mixed catalysts to promote the formation of aromatic hydrocarbon was investigated in this study. Results showed that with an increased ratio of HZSM-5 catalyst, the bio-oil yield was decreased; however, the proportion of aromatic hydrocarbons increased at first and then decreased. The maximum proportion of aromatic hydrocarbons was 35.8%, which was obtained with an optimal ratio of CaO to HZSM-5 of 1:2. This study showed the effects of CaO and HZSM-5 mixed catalysts under microwave-assisted pyrolysis in terms of improving the formation of aromatic hydrocarbons in bio-oil.

Volatile organic compounds (VOCs) were evaluated with application of a thermal load of thermal insulation boards made of expanded polystyrene (EPS). Samples of commercially produced polystyrene EPS 100S and EPS GreyWall were tested at 60 °C. For qualitative and quantitative analyses, headspace gas chromatography mass spectrometry (HS-GC-MS) was used. To reduce VOC emissions, the chemically non-bound powder graphite was added to the EPS 100S in experiments. The aim of this research was to analyse the effects of graphite bound in EPS structure and of added free powder graphite on the VOC emissions, especially styrene. The research revealed that the graphite bounded in the GreyWall EPS structure had an effect on the reduction of VOCs emissions, and reduced styrene emissions by 14.6%. The addition of powder graphite resulted in a reduction in VOCs emissions below the detection limit.

The effects of mechanical densification on density, Brinell hardness, bending strength (MOR), modulus of elasticity (MOE), and compression strength (CS) of thermally pretreated spruce (Picea orientalis) and poplar (Populus nigra) wood samples were investigated. Thermal treatment was applied on the wood samples at four different temperatures (140 °C, 160 °C, 180 °C, and 200 °C) and two different durations (7 h and 9 h) under atmospheric pressure. Wood samples were then densified by compression at a temperature of 150 °C to two degrees (20% and 40%) of compression. The results indicated that the density, hardness, and MOR values of both compressed and non-compressed thermally pretreated spruce and poplar samples decreased with increasing treatment temperature and duration. At temperatures below 200 °C, the MOE was generally increased in thermally pretreated samples. However, the MOE was reduced in thermally pretreated samples at 200 °C compared to the untreated samples. Additionally, all thermal pretreatments increased CS values in compressed and non-compressed wood samples. The CS tended to decrease in thermally pretreated samples (especially 40% compressed) at 200 ºC. After the densification, all of the strength properties tested in thermally pretreated samples increased significantly depending on the increase in compression ratio.

A series of activated carbon hollow fibers doped with charcoal powder (WC-ACHFs) were prepared from wood waste with great potential for application in the gas adsorption of CO2 and H2. The hydrogen storage of WC-ACHF-1.0% increased approximately 10.5% more than that of activated carbon hollow fibers (ACHF), and the highest hydrogen uptake reached 4.51 wt% at 77 K and 100 bar. Regarding the CO2 adsorption, the highest adsorption amount reached 7.13 mmol g-1 and the mass content was 31.35 at 273 K, which was 49.8% higher than the sample without doping. In addition, the multiple heteroatoms (N, P) from wood waste liquefaction had a synergistic effect on the gas adsorption properties of WC-ACHFs. These results showed that a facile method was promising for the preparation of wood-derived activated carbon hollow fibers from forestry and agricultural residues in the application of gas adsorption.

Biochar was prepared from agricultural plant waste, including corn straw (MS), sunflower straw (SS), wheat straw (WS), orange peel (OS), sunflower seed shell (SSS), and chestnut shell (CS) at low temperature in a partially oxygen-limited environment. These biochars were used to adsorb heavy metals and organic pollutants. The results showed that biochar having suitable surface area and microporous area could be obtained from the raw materials at 300 °C under partial oxygen limitation. The total porosity of biochar prepared from corn straw (MS) was 92.8%, and the removal of Pb2+ was 78.6 mg/g. The obtained biochar had good adsorption properties for methylene blue and Pb2+ water of different concentrations, and the adsorption performance of biochar prepared from crop straw was better than that of biochar prepared from plant peel. Thus, it was feasible to prepare biochar and to adsorb harmful substances in water through this process. This study promotes the recycling of agricultural wastes and simplifies the preparation of carbon adsorbents.

This study shows that it is possible to manufacture moulded products from fibrous pulp at the laboratory scale using the Rapid-Köthen apparatus (found in almost every paper laboratory) and a special sieve form set. This process includes the design of elements of the mould forming sets by special software, production of these elements using a numerically controlled tool machine, the assembly of the sieve form, its installation in the Rapid-Köthen apparatus, and the forming and drying of the pulp product.

Finite element simulations of coupled thermal and moisture fields in wood during kiln drying were observed with a focus on non-isothermal moisture transfer in three dimensional orthotropic models of wood with an initial moisture content below the fiber saturation point. Four different unsteady-state numerical models of the drying process were compared with the assumptions given by standards commonly used in wood kiln-drying processes. The first model describes linear simulation, and the other three models present nonlinear simulation using variable material coefficients dependent on temperature and moisture content, differing in settings of the Soret effect (thermodiffusion). A linear model was useful for predicting only the average moisture content during drying. Moreover, the nonlinear simulations were useful for computing the moisture content distribution. High differences (2.31% of moisture content) were found between the flow of moisture predicted by numerical models and standard requirements.

In the Mexican state of Jalisco, a significant amount of fibrous agave waste is generated from the tequila industry every year. The objective of this study was to establish the potential of obtaining cellulose nanofibers (CNF) from the bagasse waste of Agave tequilana, and then incorporate them into a linear medium density polyethylene matrix to obtain nanocomposites through the thermocompression process. These nanoparticles were used to prepare nanocomposites of the selected matrix, incorporating 1 to 5 wt% of CNF. All of the prepared composites had a low water absorption. Increases in tensile strength and in modulus and flexural properties occurred when the concentration of the CNF was augmented. However, in the case of nanocomposites with 5 wt%, a decrease in elongation was observed.

The wood chemical composition was determined for five tree species that cohabitate in the forest of Ixtlán de Juárez (Oaxaca, Mexico). These species were Alnus acuminata, Arbutus xalapensis, Myrsine juergensenii, Persea longipes, and Prunus serotina. The chemical composition was then correlated with the higher heating value of the wood. The chemical components determined were total extractives, ash, lignin, and holocellulose (alpha cellulose and hemicelluloses). The extractives were separated using Soxhlet equipment, and the ash obtained was analyzed via atomic absorption spectrometry. On average, the species presented 8.26 to 19.64% of total extractives, 0.56 to 1.50% of ash, 23.1 to 37.2% of lignin, 74.0 to 79.5% of holocellulose, 56.3 to 66.3% of α-cellulose, and 12.3 to 21.0% of hemicelluloses. In the ash, higher percentages of calcium, potassium, and magnesium were detected. The amount of chemical components was different between species (p ≤ 0.05). The higher heating value showed a positive correlation with the extractives content (r = 0.582), while with the ash content it was negative (-0.575). The high proportions of polysaccharides predict good performance of these species in pulp production, and the calorific value indicates that they have the potential for use as fuel.

The objective of this study was to evaluate the extent to which the practicing architects in Malaysia were familiar with timber products as a construction material. The materials consumption data was extracted from the Construction Industry Development Board (CIDB) database and was used to conduct a survey among 189 respondent architects. The results indicated that the architects were familiar with common timber products such as plywood, fiberboard, particleboard, and laminated veneer lumber. Correlation analysis of awareness and knowledge against the rate of utilization of these timber products was significant. Furthermore, the most important deterrent factors for the use of timber products in building construction in Malaysia were the high cost, poor durability, restrictive building codes and by-laws, as well as the low fire resistance. More aggressive promotion of timber products as a potential construction material is advisable to be undertaken when the goal is to boost the material’s use in the construction industry. Policy makers may also consider providing financial incentives to increase timber products utilization in building construction in Malaysia.