Volume 15 Issue 4

In recent decades, natural fibers have become widely used with petroleum based polymers such as polyethylene (PE) and polypropylene (PP) because of their light weight, lower cost, and inherent biodegradability. In the present work, linear low-density polyethylene/polyvinyl alcohol (LLDPE/PVOH) composites with untreated kenaf and silane-treated kenaf at filler loadings of 0, 10, and 40 phr were prepared via the melt mixing process. The soil burial test was used to evaluate the degradability of the composites for different durations (90 and 180 d). The tensile properties, surface morphology, chemical composition, percentage of weight loss, and crystallinity of the composites before and after degradation were evaluated. With increased kenaf loading and soil burial duration, all the composites showed a decrease in tensile properties. This was further confirmed by the changes in surface morphology and chemical structure of the buried composites. The increase in weight loss percentage and crystallinity after soil burial indicated that the longer burial duration had increased the degradation of composites. Composites with silane-treated kenaf exhibited lower degradability than that of composites with untreated kenaf after being buried for 90 and 180 d. This may be attributed to the improved adhesion of kenaf to the LLDPE/PVOH matrix via silane treatment.

Utilization of biomass for production of second generation bioethanol was considered as a way to reduce burdens of fossil fuel in Pakistan. The materials wheat straw, rice straw, cotton stalk, corn stover, and peel wastes were used in this experiment. Various parameters, such as acidic and alkali pretreatment, enzymatic hydrolysis by cellulases, and effect of proteases inhibitors on ethanol production, were examined. Fermentation was completed by the yeasts Saccharomyces cerevisiae and Clostridium thermocellum separately, and their ethanol production were compared and maximum ethanol yield was obtained with wheat straw i.e.,11.3 g/L by S. cerevisiae and 8.5 g/L by C. thermocellum. Results indicated that a higher quantity of sugar was obtained from wheat straw (19.6 ± 1.6 g/L) followed by rice straw (17.6 ± 0.6 g/L) and corn stover (16.1 ± 0.9 g/L) compared to the other evaluated biomass samples. A higher yield of ethanol (11.3 g/L) was observed when a glucose concentration of 21.7 g/L was used, for which yeast fermentation efficiency was 92%. Results also revealed the increased in ethanol production (93%) by using celluases in combination with recombinant Serine protease inhibitors from C. thermocellum. It is expected that the use of recombinant serpins with cellulases will play a major role in the biofuel production by using agricultural biomass. This will also help in the economics of the biofuel.

Reducing the formation of adsorbable organic halides during chlorine dioxide bleaching (the first stage chlorine dioxide bleaching, D0) is necessary to obtain clean bleaching processes. A new bleaching agent, ammonium thiosulfate (AT), was investigated to determine its potential for reducing the amount of adsorbable organic halides (AOX). Upon investigating the optimal reaction conditions for an effective reduction in AOX, the authors determined that adding 0.20% of AT 10 min after the beginning of the bleaching reaction, while maintaining a pH of 4 and a temperature of 70°C, yielded the best results. Under these conditions, AOX formation decreased by 22.0%. The bleaching effluent after the addition of AT was analyzed via gas chromatography-mass spectrometry, which showed an inhibited production rate of chlorobenzene and chlorophenol, which are both highly toxic and difficult-to-degrade compounds. Therefore, AT not only reduces AOX formation during the bleaching process, but also minimizes the difficulty of treating bleaching effluent. The results of this study provided a new, clean method for reducing AOX formation during chlorine dioxide bleaching.

Cellulase is a compound enzyme that catalyzes cellulose into monosaccharides or oligosaccharides. Large amounts of cellulase are needed with the development of the lignocellulose processing industry, which necessitates faster methods to produce cellulase. In this work, the marine bacterium Microbulbifer hydrolyticus IRE-31-192 was selected to produce cellulase, due to its fast growth rate and short high space-time yield. Co-fermentation of glucose and xylose to produce cellulase was investigated on the basis of previous work. When the ratio of glucose/xylose was 2:1 (w/w), 294 U/L cellulase activity with highest space-time yield of 12.2 U/L h was obtained. The hydrolytic liquid of lignocellulose prepared from dried distiller’s grains with solubles (DDGS) with the similar ratio of glucose/xylose was used as medium to produce cellulase. The efficiency of cellulase production from processed and unprocessed hydrolysates of DDGS was compared. Unprocessed hydrolysates were more beneficial for the production of cellulase, such that its activity was 261 U/L with a space-time yield of 14.5 U/L h. Thus, commonly used pure glucose and xylose could be replaced by hydrolysates of DDGS, and marine bacteria has potential application for cellulase production.

This article shows how fiber properties obtained by the compression refining of bleached softwood pulp refined using a KID 300 refiner differs from traditional bar refining. A KID refiner is a stone crusher that has been modified to refine fiber, and it offers a refining method that could be used at the mill scale. This study showed that compression refining caused more internal fibrillation compared with blade refining and improved the pulp’s ability to be beaten. Net energy consumption in compression refining was less than that of bar refining. Compression refining yielded pulp with shorter fibers and a higher number of fines, kinks, and curves. Still, the strength properties of the paper were the same level as bar-refined pulp, probably due to the higher internal fibrillation and flexibility of the fibers. It was also shown that the low field time-domain nuclear magnetic resonance (TD-NMR) method was capable of measuring the porosity and internal fibrillation of the fiber.

The effect of calcination temperature on the pozzolanic activity of corn straw leaf ash (CSLA) was evaluated. The CSLA samples calcined at temperatures of 500, 700, and 850 °C were mixed in a portlandite solution for 6 h, and residual samples were obtained. The CSLA and residual samples were analyzed using Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and a contact angle goniometer to determine the vibration bonds, minerals, phase composition, microstructure, Si 2p transformation behavior, and wetting behavior. The conductivity and loss of conductivity with mixing time of the CSLA-portlandite mixed solution was determined. The loss of conductivity of the CSLA prepared at 500 °C was high compared to that of the other calcination temperatures at the same mixing time, which was attributed to the higher amorphous SiO2 content in the CSLA at 500 °C. Calcium silicate hydrate was easily identified in the CSLA residual samples, and some dense small cubic and nearly spherical shaped calcium silicate hydrate particles were found in the CSLA residual samples at 500 °C. Based on the findings, it is recommended that CSLA be calcined at 500 °C using the cement system in view of higher pozzolanic activity but avoiding excessive agglomeration.

The optimal preparation conditions for cellulose/diatomite composite adsorbents (CDAs) were determined to be a diatomite concentration of 40 wt%, a holding temperature of 700 °C, and a holding time of 30 min. Meanwhile, the yield of CDAs was 70.6%, and the methylene blue (MB) adsorption value was 191.8 mg/g. The specific surface area, total pore volume, and average pore size of the CDAs were 489 m2/g, 0.372 cm3/g, and 3.04 nm, respectively. It was inferred that the diatomite was cross-linked with the cellulose carbon to form some micropores. Greater MB initial concentrations and pH values improved the adsorption on the CDAs. The MB adsorption behavior of the CDAs was described very well by the pseudo-second-order model. The isotherm models showed relatively high adsorption of MB.

Volatile aroma compounds in Dendrocalamus latiflorus shoots were extracted using solid-phase microextraction (SPME) and then heated at various temperatures and for various durations. Gas chromatography-mass spectrometry (GC-MS) analyses showed that frozen D. latiflorus shoots at ambient temperature contain 18 volatile aroma compounds, with limonene and 2-pentyl furan being the major components. Limonene has the fragrance of lemon and citrus fruits, while 2-pentyl furan gives off the scent of flowers and fruits. Additionally, heating temperature had a significant influence on the volatile aroma compounds. Some, including limonene, 2-pentyl furan and n-hexanal, showed marked decrement in content and vaporized almost completely at 100 C, while others, including n-heneicosane and 4-hydroxybenzaldehyde, showed pronounced increase in relative contents. Furthermore, there was a positive relationship between n-heneicosane content and heating duration but a negative relationship between 4-hydroxybenzaldehyde content and heating duration, revealing substantial effects of heating duration on the volatile aroma compounds of D. latiflorus shoots.

The lateral enlargement perpendicular to the compressive direction for small thin boards of Cryptomeria japonica was investigated to evaluate the effects of density and compressive directions to the radial (plane-sawn board) and 45 degrees of tilt to the radial (45º sawn board). Samples were impregnated with 200 and 20,000 molecular weight polyethylene glycol (PEG). The enlargement perpendicular to the fiber direction with deformation was obtained for heartwood and sapwood specimens treated only with PEG20,000. The compression ratio of specimens treated with PEG 20,000 exceeded the void volumes regardless of the wood density. Enlarged specimens of both sapwood and heartwood showed the inflection points in the force-compression ratio curve and no correlation between the compressive directions and lateral enlargement of specimens. In the local area showing the largest deformation, however, a weak positive correlation from plane-sawn boards and weak negative correlation from 45º sawn boards between the angles of compressive direction to growth ring and lateral enlargement were derived. Microfocus X-ray computer tomography in these areas showed the different morphological compressive deformations. The cells in the 45º sawn board were forced out due to each cell moving, whereas the radially arranged ones in the plane sawn board buckled under compression.

The aim of this study was to investigate the antihistamine activity of steam-exploded oak (Quercus variabilis) extract containing phenolic compounds. The antioxidant activity increased with residence time of the steam explosion process. The 50% EtOH extract had total phenolic compound content of 82.2 % and 46.2 mg GAE/g extract and vanillic acid, ferulic acid, and vanillin were identified. Treatment with 50% EtOH extract decreased the diameters of histamine-induced wheal and erythema responses in human volunteers. In patients with atopic dermatitis, topical administration of 50% EtOH extract led to significant diseases and improvement in terms of sleep disturbance, pruritus, xerosis, desire to scratch, and erythema. This study suggested that steam-exploded oak is rich in phenolic compounds with high antioxidant and antihistamine activities, and the extract may be a promising source of new antihistamine agents and pharmaceuticals.