Volume 11 Issue 4

Pyrolysis of Tamarix chinensis feedstock was performed at 300, 500, and 700 °C to investigate the characteristics of biochar, bio-oil, and syngas. Biochar yield decreased and syngas yield increased as the pyrolysis temperature increased. The biochar was characterized for elemental composition, surface, and adsorption properties. Values of pH, electrical conductivity (EC), ash, C, K, Na, and basic functional group contents all increased as the pyrolysis temperature increased, whereas P, Ca, Mg, and acidic functional groups decreased. The methylene blue adsorption capacity values were 1.78, 2.08, and 1.96 (mg g-1) and iodine 256.48, 255.51 and 76.42 (mg g-1) for the biochars produced at 300, 500, and 700 °C, respectively. The C and H contents in bio-oil ranged from 66 to 62% and 8 to 7%, while O changed from 25 to 29% when temperature was increased from 300 to 700 °C. The concentration of hydrocarbon gases, such as ethane, ethylene, propane, and acetylene, increased as the pyrolysis temperature increased. The sum of CO and CO2 occupied great percentage of the total gas, while the H2 concentration increased markedly to a maximum of 16% at 500 °C. Thus, T. chinensis is a potential feedstock for biochar and bioenergy production.

In the gasification process, one prominent factor that affects the quality of the resulting syngas is the moisture content of the biomass feedstock. Determining the moisture content of a feedstock is considered to be one of the challenges of the process. The information about moisture content of a feedstock is required to decide the need for further drying prior to the gasification process. In this study, a novel method was developed for the evaluation of the moisture content from density of oil palm fronds (OPF) in a sufficiently accurate manner for gasification process. A total of 147 samples from different sections of freshly pruned fronds were prepared. The density of each of the samples was determined from its weight and volume. A fine sand displacement method, using fine sand and a graduated cylinder, determined the volume of OPF. The moisture content of the OPF was determined from the weight difference of the samples before and after the drying process. The experiment implied a good correlation between moisture content and density of the biomass, in which the square of the correlation coefficient (R2) value was found to be satisfactory.

The effects of nano-wollastonite (NW) suspension impregnation on the fire-retarding properties of heat-treated solid wood of three species (beech, poplar, fir) were studied. Heat treatment was performed at two temperatures of 180 °C and 200 °C. Impregnation was carried out at a pressure of 3 bars for 30 min. The fire properties included ignition time, glowing time, back-darkening, back-splitting, back-firing, and length and width of the burnt area. Both impregnation with NW and heat-treatment generally improved all fire-retarding properties, although not always to a significant level. As a mineral material, NW acted like a physical shield against fire penetration into the texture of wood specimens, thus improving fire properties. Moreover, the high thermal conductivity coefficient of wollastonite increased the thermal conductivity of wood, therefore preventing the accumulation of heat at the point nearest to a piloted flame and contributing to the improvement of fire properties. The chemical degradation of wood cell components caused by heat-treatment further improved the fire properties. Cluster analysis indicated the significant effect of species on fire properties. Significant R-square values were found amongst fire properties related to the spread of fire on the surface of specimens. The combination of thermal modification and impregnation with NW provides suitable fire properties for solid wood.

Manufacturing companies are under pressure from consumers and legislation to reduce their environmental impacts. In some sectors where competition is particularly fierce, the ability to offer a product with a lighter environmental impact than the competition can be useful in significantly increasing market share. The forest industry, which harvests and processes wood, a renewable resource, also aims at being part of this trend towards transparency. Life cycle assessment (LCA) is often used to quantify the environmental footprint of harvested wood products (HWP). Based on a primary data inventory of four years of activity, this study presents an LCA of the portfolio of an innovative forest products manufacturer. The functional unit of that assessment is a cubic meter. A sensitive analysis on an economic allocation was also conducted. Because of loops in the studied system and flow conservation constraint, results of the portfolio LCA was verified using an organizational footprint assessment. From the material flow and the half-life of products, a bottom-up accounting method is suggested for integrating HWP in national greenhouse gas (GHG) inventories.

Physicochemical characteristics of biochar and its sorption potential for oxytetracycline (OTC) were investigated. Biochars from pineapple peel waste were produced via pyrolysis under oxygen-depleted conditions at 350 °C (BL350), 500 °C (BL500), and 650 °C (BL650), as well as the characteristics and polycyclic aromatic hydrocarbons contents of the samples were compared. The sorption kinetics of OTC onto the biochars was completed in three stages, i.e., a fast stage, a slow stage, and an equilibrium stage after 24 h. The kinetics data were perfectly fitted by the pseudo-second-order model with high correlation coefficients (R2 > 0.999). All of the sorption isotherms were nonlinear and well described by the Langmuir model. The Langmuir maximum sorption capacity (qmax) increased in the order of BL650 > BL500 > BL350. The thermodynamic parameters revealed that the sorption of OTC onto the biochars was spontaneous and endothermic. Fourier transform infrared spectroscopy (FTIR) of the biochars before and after sorption of OTC confirmed that the H-bonding interaction was the dominant sorption mechanism. The results demonstrated that biochars obtained from inexpensive and renewable materials could be utilized as a highly effective and environmentally friendly adsorbent for removing organic contaminants from wastewater.

Itaconic acid production by Aspergillus terreus (A. terreus) was investigated using the undetoxified enzymatic hydrolysate of steam-exploded corn stover as the sole carbon source. The fermentation conditions for A. terreus were optimized based on glucose as the carbon source. Unfortunately, wild-type A. terreus did not grow in the undetoxified enzymatic hydrolysate. Therefore, atmospheric and room temperature plasma (ARTP) mutagenesis was applied to obtain A. terreus mutant AT-90. A. terreus mutant AT-90 grew and secreted itaconic acid in the undetoxified enzymatic hydrolysate. The highest itaconic acid concentration (19.30 g/L) with a yield of 36.01% was obtained from the undetoxified enzymatic hydrolysate of 10% (w/v) steam-exploded corn stover. This work demonstrated that the A. terreus mutant generated by ARTP efficiently improved itaconic acid production from lignocellulose-based carbon source.

In recent years, research on low-energy building materials has actively progressed, with a growing interest in eco-friendly building. Strong interest has also been shown in the wooden flooring sector to improve the thermal conductivity of under floor heating systems. This study focused on improving the thermal transfer performance of radiant floor heating systems by enhancing the characteristics of the existing polyethylene underlay foam (PE foam). The thermal conductivity of the modified PE underlay foam (MPE foam) was increased by 48.1% compared with that of the PE foam. The theoretical heat flux was also calculated for the thermal conductivity, the results of which showed that the heat flux of the MPE foam was enhanced by 24.1%, compared with that of the underlay foam. To confirm the theoretical results, flooring systems were installed in the laboratory as a replica for the experiment. The velocity of thermal transfer for the laminated flooring used with the MPE foam was slower than the engineered flooring in which adhesive was used. However, the velocity of transfer was faster for the laminate flooring incorporating the PE foam. In addition, after the heating was switched off, the heat storage capacity of the laminate flooring with the modified PE foam was the highest among the tested samples.