Volume 12 Issue 3

Composite films that utilize seaweed as a matrix and oil palm shell (OPS) nanoparticles as a reinforcing material were developed. The effects of loading OPS nanoparticle (0%, 1%, 5%, 10%, 20%, and 30%) into seaweed films were determined by analyzing the physical, mechanical, and morphological properties of the films. The seaweed-based film incorporated with OPS nanoparticles at a high concentration (20% w/w) achieved the highest tensile strength (44.8 MPa) and Young’s Modulus (3.13 GPa). However, the film’s hydrophobicity (contact angle = 47.3º) and percentage of elongation at break (2.10%) were reduced. Moreover, it was observed that excessive loading of nanofillers (> 20%) reduced the tensile strength and hydrophilicity of the film. This phenomenon was attributed to the agglomeration of OPS nanoparticles and the formation of large voids on the film surface. Thus, the relative effectiveness of the various tested nanofiller contents in enhancing the mechanical strength of the composite film were found to be ranked in the following order: 20%, 10%, 5%, 30%, and 1%.

This study examined the influence of temperature and time of treatment on the density profile and hardness of surface-densified birch wood (Betula pendula Roth). An analysis of the wood density profile was conducted on the basis of the following parameters: thickness, maximum density, and the distance between the maximum density and the wood surface. Depending on the technological parameters’ values, the degree of compression of the wood was 13% to 22%, and its maximum density was 808 kg/m3 to 994 kg/m3. As a result of the modification of birch wood at a temperature of 100 °C and 125 °C, the wood was densified on one side. As the temperature of the thermo-mechanical treatment was raised from 150 °C to 200 °C, the wood became densified on both sides. The maximum density of the wood increased gradually with the increase of the temperature of the press plate. The longer the time of thermo-mechanical treatment, the more distant the maximum density area was from the wood surface. Depending on the temperature and the time of treatment, the hardness of the surface-densified birch wood was 1.4 to 2.2 times greater than the hardness of non-densified wood.

The study was carried to determine the labile carbon contents in biochar pyrolyzed under different temperatures and its effect on urea hydrolysis rate. Corn stovers were pyrolyzed at highest temperature of 300°C, 500°C and 700 °C to produce fresh biochar. Soil incubation experiment was conducted with biochar application rate of 0% and 2% with presence of urea. The results showed that biochars accelerated urea hydrolysis, and high temperature pyrolyzed biochar have more significant effect on soil pH enhances and acceleration of urea hydrolysis than biochar pyrolyzed at low temperature. Moreover, biochar produced at 300°C contains relative high concentration of labile carbon, and 43-64% of labile carbons were oxidized within 40 days incubation. The labile carbon in biochars also leaded microbes thrives and resulted in accelerate short-term N turnover. i.e. at early stage of incubation, fresh biochar increased mineralization of soil N by 79-449 mg•kg−1, and matured biochar by 30-61 mg•kg−1, but microbial immobilization effect was observed in fresh biochar-amended soil at the end of incubation. We concluded that aged biochar is suitable for simultaneous soil amendment with urea rather than newly produced biochar as it can promote available N accumulation in short time thus increase the risk of inorganic nitrogen leaching loss.

The effect of composition and heating value of torrefied biomass under an oxidizing atmosphere at different conditions (180, 210, and 240 °C during 30, 75, and 120 minutes) was studied relative to downdraft gasification performance. An extended model for gasification in thermochemical equilibrium was used to evaluate the effect of pretreated biomasses, fuel-to-air equivalence ratio, and char byproduct production on the producer gas composition, reaction temperature, cold gas efficiency (CGE), and the engine fuel quality (EFQ). The model was validated with experimental data, reaching a global relative error of 8.5%. For raw or torrefied biomasses, with regard to char production, the CGE decreases if char increases; this is due to the fact that the process tends to combustion regimes when a lower amount of carbon is involved in the gasification reaction. Otherwise, the CGE and EFQ increase (up to 80% and 2.5 MJ/kg, respectively) if fuel-to-air ratio increases. With regard to the torrefied biomass, it is highlighted that CGE and EFQ increase from 77% to 82% and from 2.2 MJ/kg to 2.5 MJ/kg, respectively, when the torrefaction conditions (temperature and/or time) increase. This behavior is related to the increase of the autothermal zones in the gasification process and due to the higher heating value of torrefied biomass.

A novel TiO2-wrapped nanofiber composite catalyst, which possessed a unique porous structure and mixed crystalline phase, was prepared by the combination of superficial sol–gel and post-calcination processes. By means of the superficial sol–gel process, TiO2 layers were deposited on the surface of each nanofiber-like cellulose fiber, and then the TiO2-wrapped nanofiber composite catalysts were calcined at different temperatures under a nitrogen atmosphere. With temperature increasing, the original cotton nanofiber composites were converted into porous carbon nanofiber catalysts wrapped by a TiO2 mixed crystalline phase, which was accompanied by a crystal transformation. The photocatalytic activity of the new catalysts was evaluated by the degradation of methylene blue (MB) under ultraviolet (UV) irradiation. The results demonstrated that the new catalysts had good photocatalytic ability, and the TNC-700 catalyst showed a superior photocatalytic ability compared with the other catalysts; the new catalysts had a unique porous structure, high specific surface area, and mixed crystalline phase. Additionally, the synergistic photocatalytic effect of the TiO2 and activated carbon nanofiber resulted in the efficient degradation of organic pollutants in water or air.

A renewable bio-based thermosetting adhesive named tannin-furanic-formaldehyde (TFF) resin was synthesized using natural raw materials from crops and forest, such as furfuryl alcohol and bayberry tannin. The thermal properties of the adhesives were studied using differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermal gravimetric analysis (TGA). The structure of the TFF resin was characterized by electrospray ionization mass spectrometry (ESI-MS) and Fourier transform infrared (FTIR) spectroscopy. The results indicated that TFF resin was easily prepared. Moreover, it showed an excellent modulus of elasticity (MOE) and thermal resistance. Moreover, the cross-linking reaction of bayberry tannin, furfuryl alcohol, and formaldehyde under acid condition was established.

To utilize hemicelluloses from biomass as a feedstock to produce various value-added products, the soluble hemicelluloses must be isolated from the liquid phase with a high yield and purity. In this study, acacia wood was extracted by hydrothermal treatment, catalyzed by acetic acid at 170 °C for different lengths of time, and then precipitated after concentration and mixing with ethanol. Acetic acid led to faster hydrolysis of hemicelluloses, a process that was confirmed by a larger amount of total saccharides than the controlled results. A yield of more than 90% oligosaccharides was achieved in the hydrolysate with 1% (w/w) acetic acid. The maximum precipitate yield obtained was reduced, but a faster increase was observed in the first 30 min at 170 °C depending on the utilization of acetic acid. Analysis of 13C nuclear magnetic resonance (13C NMR) confirmed that the side chains, such as arabinose linked on the xylan chain, were severely broken down, and more dissolved hemicelluloses bonded with lignin (LCC) were present in the precipitates with 1% (w/w) acetic acid. Based on gel permeation chromatography (GPC), a molecular weight of not less than 1900 is suggested when ethanol is used to precipitate the oligosaccharides from hydrolysate.

A novel method was introduced to evaluate the quality of fiber material from paper for recycling. The new concept, fiber integrity value, its components, and its relationship with paper strength properties were examined in more detail. The effect of deinking and screening on fiber integrity value, and its component parameters was shown. The fiber integrity value is closely connected to the strength potential of the pulp. It was shown that when the bonding degree was also considered, there was very good correlation with the tensile strength, tensile stiffness, and compressive strength (SCT) values. The fiber integrity value concept can be determined based on data from in-line analyzers.

Interest in the use of beech as a raw material in engineered wood products for structural purpose has increased in Europe, in particular laminated veneer lumber (LVL). Indeed, this kind of product has exhibited superior mechanical properties with a lower variability compared to solid wood. This study investigated the influence of the forestry management system (e.g., high forest versus coppice) and of the veneer defects (e.g., knots and joints) on the mechanical properties of beech laminated veneer lumber (LVL) beams. The research included the measurement of modulus of elasticity and bending strength of 40 LVL beams (50 x 50 x 1200 mm3). Bending strength and modulus of elasticity of beam made from high forest wood compared to coppice wood were respectively higher by 20% and 12%. The impact of natural and manufacturing-process defects on the bending strength was studied using an X-ray imaging system. Defects in the inner layer of LVL beams were detected via X-ray. The defects produced by the manufacturing process itself had an effect on the bending strength similar to the natural defects of wood.

Chemical constituents of naturally decayed Qinghai spruce branches were analyzed in terms of holocellulose, lignin, and pentosan. The holocellulose content declined from 57.98% to 35.29% in one year. The rate of change may be related to weather conditions, i.e., the rate of variation was higher when the temperature was high and rainfall was abundant. The changes in lignin and pentosan relative content were completely different from holocellulose; they increased first and then decreased during the decay period. Compared with fresh raw materials, pentosan content (from 14.44% to 25.9%) was increased by 79.4% after four months decay. The highest yield of furfural (10.2%) prepared by a two-stage method from decayed Qinghai spruce branches was similar to the reported yield from corncobs.