Volume 11 Issue 3

Coal and torrefied biomass co-gasification is one of the potential solutions to the reduction of greenhouse gas emissions. For this study, Jatropha seed cake was torrefied at a temperature range of 200 to 300 °C under a nitrogen atmosphere. The torrefied material was then co-pyrolyzed and isothermally co-gasified at 900 °C with two Illinois (IL) #6 coal chars in a fixed-bed reactor connected to an on-line gas chromatography analyzer. Carbon dioxide and carbon monoxide were the primary gas products from the torrefaction process. Kinetic models, such as the shrinking core model, the homogenous model, and the catalysis-controlled model, were used to analyze the gasification mechanism. The results showed that the shrinking core and homogenous models provided the best fits for the gasification reaction data. Jatropha seed cake torrefied at 260 and 280 °C exhibited the best reaction activity with the IL #6 coal chars. The reactivities of coal char with torrefied biomass obtained at 200 and 300 °C were lower in comparison with the others.

This study characterizes and compares coffee chaff (CC) and spent coffee grounds (SCG), the two most useful coffee waste products, and evaluates their performance as fillers and/or reinforcing agents in polymer composites. The morphologies of the CC and the SCG were studied using a scanning electron microscope (SEM). Detailed compositional and elemental analyses of the samples were carried out using several techniques. The thermal stabilities of the two types of biomass were evaluated using thermogravimetric analysis (TGA). Infrared spectroscopy was performed to investigate the functional groups available on the surface of the biomass. It was found that the CC had higher thermal stability, lower fat content, and a denser fibrous structure than the SCG, making it potentially a more suitable material than the SCG for use as a reinforcing filler in polymer composites. To verify this potential, CC and SCG filled polypropylene composites were produced and evaluated.

To reuse waste wood bioresources and determine the factors required for the growth of Lentinus edodes, Quercus baronii wood bioconversion during the artificial cultivation of L. edodes was characterized by X-ray diffraction (XRD), TG, FT-IR, and TD-GC-MS. Mycelia were observed to grow in wood if cellulose was sufficiently degraded and wood extractives were adequately retained. L. edodes grew inwood if the extractives, cellulose, hemicellulose, and lignin maintained a stable quality ratio. Mycelium and L. edodes grew in samples with high cellulose crystallinity. FT-IR spectra showed that L. edodes grew as the intensity of absorbance associated with unconjugated C=O stretching decreased. TG curves suggested that the samples with lower weight loss were suitable for mycelium, but those with higher weight loss were suitable for L. edodes. TD-GC-MS indicated that the samples containing more phenol derivatives and less acetic acid were suitable for mycelium; the opposite trends were observed for L. edodes.

Lignocellulosic biomass as a renewable and valuable resource has been a very active research area during recent years. Ionic liquids (ILs) are an attractive approach for the pretreatment of lignocelluloses. In this work, a series of pyrrolidinium-based ionic liquids were prepared simply and were investigated for the pretreatment of corn stalk at 90 °C for 30 min. The characteristics of regenerated lignin and cellulose-rich materials were determined by Fourier transform infrared spectroscopy (FTIR) analysis. Both ILs and ILs/H2O were studied. Notably, 10.17% lignin based on the original corn stalk was recovered with [Hmp]Cl-pretreatment; 21.34% and 15.83% reducing sugar based on the original corn stalk were observed during pretreatment with [Hmp]HSO4/H2O and [Hmp]Cl/H2O pretreatment, respectively; 80.54% of reducing sugar was obtained based on the cellulose-rich materials with [Hmp]Cl/H2O-pretreatment. Also, the glucose and cellobiose yields were 73.82% and 8.64%, respectively.

Heat-treated wood has an ever-expanding market for exterior and interior applications. The objective of this study was to determine the effect of a heat treatment on the bonding strength of hornbeam (Carpinus betulus L.) wood that was bonded with melamine formaldehyde (MF), polyurethane (PUR), and polyvinyl acetate (PVAc-D4) adhesives. Hornbeam lamellas were heat treated at 150 °C, 175 °C, 200 °C, and 225 °C for 3 h and then bonded. The bonding strength of the specimens was determined. In addition, the density, weight loss, and pH value of the heat-treated wood were investigated. The results showed that the bonding strengths of the heat-treated wood specimens decreased with the temperature of the heat treatment. The bonding strength of the PUR adhesive was higher than the MF and the PVAc-D4.

A new deformation technique of wood flow forming is promising for industrial uses of solid wood. Flow deformability, size stability, and good mechanical properties were obtained by using wood impregnated with low molecular weight phenol formaldehyde (PF) resin. In this study, to clarify the effect of the PF resin and moisture contents in wood on the flow deformability (extrudability) and the mechanical properties of the product (extrudate), a lateral extrusion was conducted by using wood impregnated with various contents of PF resin and three levels of moisture content. The results indicated that the extrudability of wood impregnated with PF resin improved with an increase in both PF resin and moisture content. The mechanical properties of the extrudate worsened with increases in the moisture content of the wood impregnated with PF resin. Because most of the water in the wood remained in the mold during the extrusion process, chemical changes of the wood substance and PF resin occurred due to steam forming under the high temperature and pressure of the extrusion. The steam worsened the mechanical properties of the extrudate.

This effects of ozone and nanocellulose treatments were studied relative to the optical and strength features of chemical mechanical pulp (CMP) papers. An ozone treatment was performed at room temperature, and then nanocellulose was added. Sixty-gram handmade papers were made, and their physical, mechanical, and morphological properties were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). With the ozone treatment, changes in the optical features were not significant at the 95% level; however, the addition of nanocellulose led to significant changes: the tensile strength, burst strength, air resistance, opacity, and brightness increased by 14.1%, 15.9%, 34.8%, 2.8%, and 3.2%, respectively, in comparison with the control sample. The enhancement with nanocellulose reduced the tear strength, coarseness, and yellowness by 15.7%, 12.9%, and 7.6%, respectively, compared with the control sample. The crystallinity of neat nanocellulose was 65.59%, while the crystallinities with the use of 5% to 10% nanocellulose were 72.41% and 62.26%, respectively. The SEM results indicated that using a 10% nanocellulose treatment led to the reduction of the CMP paper’s porous character.

The aim of this research was to fabricate epoxy nanocomposites by utilizing the developed nano filler from oil palm mills agricultural wastes oil palm empty fruit bunch (OPEFB) fibers for advanced applications. Epoxy-based polymer nanocomposites were prepared by dispersing 1, 3, and 5 wt. % nano OPEFB filler by using a high speed mechanical stirrer through hand lay-up technique. The mechanical (tensile and impact) properties and morphological properties of nano OPEFB/epoxy nanocomposites were examined and compared. Morphological properties were analyzed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to look at the dispersion of the nano OPEFB filler in the epoxy matrix. The tensile and impact properties of nanocomposites increased until 3% nano filler loading, but beyond 3% they decreased. Overall mechanical properties reached maximum values for 3% loading, due to better stress transfer owing to homogenous dispersion of nano OPEFB filler within epoxy matrix. The observed results were also confirmed by SEM and TEM micrographs.

This study aimed to investigate the major content of merbau extractives (ME) and their potential use as an impregnating material for low-quality timber. Extraction was done by maceration with ethanol, ethyl-acetate, and hot-water. Physico-chemical, phyto-chemical, UV-visible, and infrared spectroscopy, as well as py-GCMS analysis were then performed on dried extract. The results showed that organic solvent extractions resulted in much higher yields, by 12.50% than that of hot water (1.10%). The merbau extractives liquid obtained had a low acidity, with a pH ranging from 5 to 6, which is typical of phenolic compounds. Flavonoids and phenolics were found as the major compounds.  UV-vis spectra showed that ME (λ=279 nm) consists of conjugated or aromatic systems, similar to standard resorcinol, which was used as the reference (λ=274 nm). The FTIR spectra showed the absorption bands at 3369 cm-1 that represent the functional group of hydroxyl (OH) bonds, and 1619 and 1510 cm-1, representing the aromatic ring (C=C), which could be associated with resorcinol. The Py-GCMS showed that ME is predominated by resorcinol (C6H6O2) with a 79% concentration. The ME could be potentially used for producing phenolic/resorcinolic resin through polymerization, which could be applied for wood impregnation.

Tannin-furanic biobased foams, based on the co-reaction of bark-derived condensed tannins and thermoset furanic polymers, have low thermal conductivity, are self-extinguishing, and have high fire resistance, which allows their development for several industrial uses. One of their main drawbacks, however, is the absorption of water within the foam itself. Another problem is the rather friable surface, which is a definite drawback for some potential applications. In this work, these two problems are minimized or eliminated by introducing a component of oil-grafted tannin in the foam formulation. The incorporation of fatty chains markedly decreased foam friability and increased water repellency in the body of the foams. These properties and the compounds formed by fatty acids grafting onto the tannin flavonoids were extensively tested.