Volume 13 Issue 2

Difficulties in fractionation and subsequent conversion of lignocellulosic biomass have restricted the development of sustainable biorefineries of lignocellulosic materials. Herein, an aqueous glycerol/acidic ionic liquid (AGAIL) process of coir was carried out under atmospheric and autogenerated pressure to investigate the lignocellulose fractionation and understand the main conversion products generated during the process. Additionally, the depolymerization capacity of the AGAIL system on lignin was also estimated by analyzing the main degradation products. The results indicated that the process under autogenerated pressure presented much higher delignification efficiency and more effective lignocellulose conversion capability than those under atmospheric pressure. Ribitol and monomeric aromatic compounds were identified by gas chromatography-mass spectrometry (GC-MS) as the main conversion products of carbohydrates and lignin, respectively. The glycerol/AIL system was shown to be able to depolymerize coir lignin with a resulting lignin depolymerization extent of 28.1%. The main lignin depolymerization products were monomeric aromatic compounds.

The high-speed steel (HSS) cutting tool edge recession increase (VB) from milling wood of nine wood species with very different properties were analyzed. Theoretical simulations showed that the synergistic effect of the wood density (D), hard mineral contamination (HMC), and high temperature tribochemical reactions (HTTR), as well as initial edge recessions were important factors that accelerated wearing on the examined cutting edges.

The effects of lignin-combined manganese ion, iron ion, and lignin-combined iron and manganese on the decomposition of hydrogen peroxide were investigated. Elemental analysis and inductively coupled plasma-atomic emission spectrometry were used to analyze the chemical features of the lignin composites and the amount of metal ions present in the solution or adsorbed on lignin, respectively. The results showed that the main transition metal elements remaining in the precipitated lignin were Fe, Mn, and Cu. The hydrogen peroxide decomposition in the presence of lignin-combined transition metal was represented by pseudo-first-order kinetics, and the pseudo-first-order rate constant (kobs) of peroxide decomposition with lignin-combined iron was 0.0068 min-1, while it was 0.0063 min-1 in the presence of lignin-combined manganese. A synergistic effect of manganese and iron combined with lignin on peroxide decomposition was demonstrated, and a kobs value of 0.0053 min-1 was obtained. The mixed addition of magnesium sulfate (MgSO4), sodium silicate (Na2SiO3), and ethylene diamine tetraacetic acid disodium salt (Na2EDTA) resulted in an optimal reduction in peroxide decomposition when single lignin-combined metal ion existed. However, adding Na2EDTA alone had an optimal effect on the reduction of peroxide decomposition in the presence of lignin-combined iron and manganese, with a kobs value of 0.0004 min-1.

A simple procedure was evaluated to prepare cost-effective heteroatom self-doped porous carbons from edamame shell using a two-step carbonization and activation process. The morphological, structural, textural properties and N2/CO2 adsorption–desorption were investigated. The results showed that edamame shell, which is abundant in nitrogen and oxygen, is an ideal precursor for preparing heteroatom self-doped porous carbons. The N and O contents of the prepared activated carbons (ACs) ranged from 1.20 wt% to 1.81 wt% and 5.13 wt% to 9.98 wt%, respectively. Furthermore, the specific surface area of 1835 m2/g of the N and O doped ACs resulted in mainly microporosity, which suggested that it has promising potential for wide applications in the fields of catalysis, energy conversion, energy storage devices, and adsorption.

The possible use of formamidine sulfinic acid (FAS) for pre-bleaching of colored office paper in the stage of pulping was investigated. In addition, the effects of FAS pre-bleaching on different colors were examined. Colored office papers were mixed with white office paper at a 1:4 ratio. FAS was added as 0.25%, 0.50%, 0.75%, 1.00%, and 2.00% into the pulper. Reduction ability of colors with FAS were determined as yellow, red, green, and blue according to L*, a*, b*, ΔE, and reflectance spectrum at 220 nm to 900 nm wavelength. In other words, it was determined that FAS succeeded on the yellow, red, and green colored waste paper, but it failed on the blue colored waste paper at 10 minute pre-bleaching conditions. On the other hand, in mixed colored waste paper, which can better represent industrial applications, the color difference (ΔE) were calculated as 32.0 with 1% FAS pre-bleaching. This result is successful for pre-bleaching, which is an auxiliary process during re-pulping of waste paper.

The feasibility of using orange peel residues as a substrate for induced sporulation of Trichoderma asperellum was evaluated. The Box-Behnken matrix (BBM) design was used to screen the effects of several parameters, including the effect of pH, inoculum, and moisture under solid-state fermentation culture conditions. The study was performed in two experimental steps (screening and optimization). Moisture content and pH were determined to be the most influential parameters on spore production during the screening stage. A Box-Behnken design was used to optimize and to define the interaction of the selected parameters. The moisture content was determined as the most significant parameter affecting spore production. An inoculum of 1 × 106 spores g-1, pH 6.07, and moisture content of 69.0% was the combination of conditions observed to achieve the maximum production of 2.04 × 109 spores g-1. The experimental value of 2.16 × 109 spores g-1 (from the experimental model) showed a good fit to the regressed model, with a standard error of 5%. Based on this work, a high yield of spores was obtained at 144 h of cultivation time, indicating that it is a feasible approach to use orange peel as a substrate for biomass and spore production.

A new thermally conductive copper paper was prepared with cellulose pulp and ultrafine copper powder in a traditional paper making process. The thermal conductivity of the copper paper was studied in different weight ratios, and the surface morphology was observed by scanning electron microscopy (SEM). The results showed that the addition of copper powder enhanced the thermal conductivity of copper paper distinctly, with a maximum of up to 0.560 w•m-1•K-1 in the weight ratio of pulp/copper of 1:12, which was an increase of 143% compared with the paper without copper. Scanning electron microscopy images showed that copper papers consisted of copper powder particles distributing compactly on the fiber surface. The tensile index of copper paper decreased compared with the paper without filler. A calendaring process was used to improve the combination between copper particles and fibers and to enhance the thermal conductivity of copper paper.