Research Articles

Miscanthus, which is comprised of several different genotypes, is an important high-biomass crop with applications in the biofuel industry and in the formation of biocomposite materials. The overall composition of Miscanthus can be altered via degradation with wood rot fungi. The starting composition revealed that the cellulose content of Miscanthus x giganteus was higher than that in Miscanthus sacchariflorus and that the lignin contents were similar in both genotypes. Of the wood rot fungi, only Lentinus edodes appeared to have completely colonized M. sacchariflorus and showed significant degradation. In contrast, all of the brown rot fungi showed partial colonization of both Miscanthus genotypes and had little effect on the fibrous composition. Cellulose degradation by some white rot fungi increased with cellulose content whereas cellulose degradation by other fungi was independent of cellulose content. All of the white rot fungi showed similar rates of lignin degradation, except for Pleurotus ostreatus, which was higher on M. sacchariflorus. The effect of the moisture contents of Miscanthus on cellulose and lignin decomposition by Phlebiopsis gigantea SPLog6 and Coniophora puteana 11E was also investigated. These results revealed subtle differences in the growth of white rot fungi on different Miscanthus genotypes.

The purpose of this study was to investigate a popular reinforcing agent in the papermaking industry through a quick, environmentally friendly, microwave-assisted method. The preparation and characterization of cellulose-CaCO3 composites through this route, in a mixed solution of an ionic liquid and ethylene glycol, can occur within a 10-min timeframe. The chemical compounds, calcium acetate and sodium carbonate, were used as reactants for the as-obtained CaCO3 crystals. A NaOH-urea aqueous solution was used to treat the cellulose and prepare cellulose-CaCO3 composites. It was discovered that the addition of ionic liquids favors the preparation of cellulose-CaCO3 composites.

The heat of combustion relative to the mass, Qm, was evaluated for 13 deciduous wood species, ranging from low to high density. The maximum and minimum values for Qm ranged, respectively, from 19.01 kJ∙g-1 (Sd = 7 J∙g-1) to 21.66 kJ∙g-1 (Sd = 6 J∙g-1) for Populus tremula and Alnus glutinosa wood. The average value of the Qm for all wood specimens evaluated in the present study was 19.93 kJ∙g-1 (Sd = 706 J∙g-1), which is 1.6% higher than the value reported in the literature (Krzysik 1975). A high correlation, R = 0.99, was observed between the volumetric heat of combustion, Qv, and wood density, D0. No correlation was discovered among Qm, D0, the ash content in the wood, ac, as well as the content of the following elements in the ash: calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), silica (Si), aluminum (Al), iron (Fe), copper (Cu), manganese (Mn), sulfur (S), and phosphorus (P).

The physical and chemical properties of raw bio-oil, two oxidized bio-oils, and hydrotreated bio-oil were compared before and after catalytic hydrodeoxygenation using sulfided CoMo/γ-Al2O3 catalyst. Following continuous hydrodeoxygenation, the organic liquid products from treated bio-oils and raw bio-oil were compared for higher heating value, oxygen content, water content, and viscosity. In addition, Fourier transform infrared spectroscopy and gas chromatography/mass spectrometry were employed to identify functional groups and chemical species, respectively. Fresh and spent catalysts were characterized by nitrogen adsorption-desorption for surface area and pore properties. The degree of coking of the spent catalysts was analyzed by thermogravimetric analysis. Hydrodeoxygenation of hydrotreated bio-oil (HB) gave the longest reaction time on stream of 780 min, the least coking amount of 20 wt%, and the highest hydrocarbon selectivity of 70% up to 720 min of reaction time on stream. Moreover, organic liquid products from HB showed relatively stable properties such as low oxygen content, water content, and viscosity over a longer period of reaction time on stream.

A new class of leaf stalk fibers of the palm tree were extracted and treated with a 5% NaOH solution for 1 h, 2 h, 6 h, and 12 h. The treated fibers were then characterized by tensile strength testing, chemical analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and solid state NMR. The tensile strength of the fibers was improved with an alkali treatment, and the 6 h treatment resulted in the maximum fiber strength. The maximum cellulose content was present in the 6 h-treated fibers; cellulose content was reduced with a longer treatment (12 h). Similarly, SEM, FTIR, XRD, and NMR confirmed the removal of hemicelluloses from the raw fiber surface and the formation of new hydrogen bonds between the cellulose fibril chains with respect to the duration of the treatment. The 5% alkali treatment also improved the fiber density from 0.85 gm/cc (raw fiber) to 1.05 gm/cc, 1.13 gm/cc, 1.17 gm/cc, and 1.25 gm/cc after the 1 h, 2 h, 6 h, and 12 h treatments, respectively.

The acidic solvolysis of lignocellulose using a glycol solvent such as polyethylene glycol (PEG) is a promising process for separating its components and producing a valuable lignin product that can be used as thermoplastic and fusible materials. To decrease operational costs, a glycol solvent that is used as a solvolysis reagent must be recovered and reused. In the present study, PEG was recovered by the removal of water by evaporation from the supernatant after glycol lignin production by acidic solvolysis of Japanese cedar using PEG with an average molecular weight of 200 (PEG200). The recovered PEG200 worked as a solvolysis reagent and produced glycol lignin with appropriate yield. The thermomechanical analysis of glycol lignin from the fresh and recovered PEG200 systems exhibited two inflection points, which were assigned to a glass transition point (Tg) and a thermal softening point (Ts). The Ts of the glycol lignin from the recovered PEG200 system was higher than that from the fresh PEG200 system. These results suggest that the glycol lignin from the recovered PEG200 system had high thermostability as well as high thermal fusibility.

Moso bamboo (Phyllostachys pubescens Mazei ex H. de Lebaie), one of the most commonly used species in China, is a strong and stiff material. In this paper, the manufacturing process for glued bamboo laminate (GBL) is presented. The mechanical properties of GBL (compression strength, bending, tension, and shearing) were tested. Results indicated that the mechanical properties of GBL were significantly different for different grades of GBL, but that the performance of GBL was controllable. The edge butt joint greatly influenced the tensile performance, but the butt joint had little impact on the bending performance. In addition, the good mechanical performance of GBL is sufficient for engineering members, making it a potentially useful bamboo product for engineering.

This study investigates the effect of modified wheat straw on the physical and mechanical properties of modified wheat straw/high-density polyethylene (MWS/HDPE) straw-plastic composites. Wheat straw fibers with particle sizes in the range of 0.25 to 0.50 mm were modified with caprolactam (CPL). A Fourier transform infrared spectroscopy (FT-IR) analysis of MWS showed that when the CPL level was 5%, the intensity of the hydroxyl (O–H) and carbonyl (C–O) absorption peaks noticeably decreased, indicating a corresponding decrease in the polarity of the fibers. A physical analysis of the wheat straw fibers indicated that after the modification, the characteristics of the fibers were closer to those of the HDPE polymer matrix, thus contributing to good compatibility and dispersion of the straw fibers within the matrix. The composites of the high-density polyethylene with modified wheat straw particles were successfully synthesized using the melt blend method. The prepared composites were characterized using scanning electron microscopy (SEM), and their mechanical properties were investigated. The MWS/HDPE composites showed superior mechanical properties because of a greater compatibility of MWS with HDPE. The modified WS fibers function as “biological steel,” reinforcing the HDPE to produce bio-composites.

Palm kernel shell (PKS) core fibers, an agricultural waste, were chemically modified using N-(3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHMAC) as a quaternizing agent. The potential of quaternized palm kernel shell (QPKS) as an adsorbent for fluoride in an aqueous solution was then studied. The quaternized palm kernel shell (QPKS) core fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and a scanning electron microscope (SEM). The effect of various factors on the fluoride sequestration was also investigated. The results showed that with an increase in the adsorbent amount and contact time, the efficiency of fluoride removal was improved. The maximum fluoride uptake was obtained at pH 3 and a contact time of 4 h. The adsorption behavior was further investigated using equilibrium isotherms and kinetics studies. The results from these studies fit well into Freundlich, Redlich-Peterson, and Sips isotherm’s with a coefficient of determination (R2) of 0.9716. The maximum fluoride removal was 63%. For kinetics studies, the pseudo-second order was the best fit for fluoride, with an R2 of 0.999. These results suggest that QPKS has the potential to serve as a low-cost adsorbent for fluoride removal from aqueous solutions.

The photo-stabilizing effect of post-extraction was evaluated for thermally modified wood. Extracted and non-extracted thermally modified Scots pine (Pinus sylvestris L.) samples were exposed in a xenon weather-ometer for 1008 h, and the surface color and chemical changes were characterized using a chroma meter, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray photoelectron spectroscopy (XPS). The results showed that: (1) the weight losses of thermally modified wood were higher than those of unmodified wood after extraction due to the leaching of some low molecular weight compounds that were generated during thermal modification; (2) the photodegradation of thermally modified wood during weathering was hindered by the presence of extractives; and (3) the color change during weathering was a little more severe in sapwood than in heartwood because more extractives were present in heartwood.