Volume 7 Issue 1

Fructose can be efficiently converted to 5-hydroxymethylfurfural by using the functionalized ionic liquid 3-(2-chloroethyl)-1-methylimidazolium chloride as both solvent and catalyst in the presence of water. This work advances the field and is distinct from earlier efforts in the sense that the observed yields of HMF from fructose are rather high and the reaction conditions rather mild and neutral in the complete absence of acidic additives (HMF yield 76% at 100 oC in 40 minutes).

A novel process involving a paper-based ultrafiltration (UF) membrane was developed via paper coating technology. The membrane employed a paper sheet as support layer and a coated thin film layer of adhesive. The proper selection of paper sheet support layer was crucial to the performance of the ultrafiltration membrane. A paper sheet with beating degree of 85oSR and basis weight of 50g/m2 was chosen as the support. PVA was chosen as the adhesive. The paper-based ultrafiltration membrane achieved high retention performance while using a simple production process and keeping the production cost low. Disadvantages of the membrane included low porosity and low pure water flux. So further investigation is still needed to produce a fully satisfactory paper-based ultrafiltration membrane.

Phenolated lignosulfonate was introduced into the synthesis of phenolic resol with phenol and formaldehyde in an alkaline condition. The modified resol was successfully applied to prepare phenolic foam using appropriate combinations of flowing agents. N-pentane was found to be suitable as the foaming agent. Sulphuric acid (50% aqueous solution, w/w) and Tween-80 were used as catalyst and surfactant, respectively. The obtained foams were characterized by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), friability, and mechanical property tests. The experimental results showed the foam to have lower density, better toughness, and excellent thermal insulation compared to those of foams obtained from conventional resol resin. The properties of phenolated lignosulfonate modified phenolic foam can comply with the required specifications for its practical utilization.

In this study it was aimed to improve impregnability of spruce (Picea orientalis L.) wood with bacteria (Bacillus licheniformis A1) pretreatment, using copper/chromium/arsenic Type C (CCA-C) andcopper azole Type A (CBA-A). The effects of Bacillus licheniformis A1 on weight loss, copper uptake, and compression strength of samples were determined. Weight loss was slightly changed by bacterial degradation in all test groups. The best copper uptake cases were 1466 ppm for CCA-C and 2730 ppm for CBA-A. Improvement on copper uptake with bacteria pretreatment was in a range of 18 to 103% compared to control samples. Compression strength was decreased by bacterial degradation. However strength losses might be acceptable for several construction applications. Bacillus licheniformis A1seems to havea good potential for increasing the permeability of spruce wood.

Organosolv pretreatment was applied to Chinese using the acid-catalysis ethanol method to enhance sugar recovery in enzymatic hydrolysis. A Box-Behnken design (BBD) was used to optimize the effect of temperature, ratio of wood to liquor, ethanol concentration, and holding time on the pretreatment process. All variables except for lignin content were found to significantly affect the cellulosic yield as well as crystallinity index (CrI). Quadratic polynomial equations were used to model on the cellulosic yield, CrI, and lignin content for a regression analysis, using response surface methodology (RSM). The optimum process of organosolv pretreatment of Chinese was found to be: temperature: 185 ºC, ratio of wood to liquor: 1 to 4.2, ethanol concentration: 45%, and holding time: 41 min. The solid pretreated under optimum process conditions was evaluated for bioconversion using enzymatic hydrolysis of the cellulose fraction to glucose. Approximately 87% of the total cellulose in the poplar was recovered as monomeric glucose after hydrolysis of the solid fraction.

Enzymes still exhibit activities after hydrolysis of biomass according to previous studies. Recycling the enzymes and use them in subsequent hydrolysis cycles can further utilize their remaining activities. Previous studies have mainly discussed enzyme recycling processes up to three cycles, in which the processes did not reach steady state. Steady state investigation is essential for the guidance of the real life process. Four cycles of processing have usually been considered enough to bring the system to steady state in process engineering. In this work, hydrolysate was used as the source of recycled enzymes to fresh substrate for five cycles. Because a large amount of enzymes remained on the pulp, surfactant was introduced to recycle the enzymes that remained with the residue. Recycled hydrolysate from previous enzymatic hydrolysis usually carries a high concentration of sugars, which can inhibit the new round of hydrolysis. To remove sugar from the recycling stream, a wash with fresh buffer was performed. Sugars were removed, while enzymes still remain on the fresh substrates. Six recycling strategies were evaluated for enzyme recycling percentage and enzymatic hydrolysis efficiency with both green-liquor pretreated softwood and hardwood in this investigation. Hydrolysis efficiency increased by about 40% for softwood at 30 mg/g enzyme dosage and about 25% for hardwood at 7.5 mg/g when a washing stage was applied with addition of surfactant.

Fire retardant particles (guanylurea phosphate and boric acid) with a morphological characteristic of large crystal or fine microsphere, were respectively applied to wood fibers to make medium density fiberboard (MDF). The effects of particle size of the fire retardant on the combustion performance of the resulting MDF samples were determined using a thermogravimetric (TG) analyzer and cone calorimeter (CONE). The scanning electron microscopy and laser particle size analysis showed that the microspheric particles of fire retardant had a mean size of approximately 20 µm, which was smaller than the crystal (260 um). rporation of the fire retardant either in the crystal or microsphere shape reduced the weight loss of the resulting MDF, as evidenced by the TG analysis and the CONE test; release rate and total amount of both the heat and smoke were apparently Treatments caused an increase in both the ignition time and charring ratio of the MDF. Compared with the fire retardant crystals, the fine microspheric particles exhibited greater ability in inhibiting the release of heat and smoke through the combustion processes.

Kraft pulp and wood powder rom Acacia Spp. were selected for the development of rapid, minimally-destructive, and predictions of kappa number and pulp yield, by means of near infrared reflectance (NIR) spectra. The models, based on Partial Least Squares Regression (PLS-R), were established with fifty-four calibration samples selected by Principle Component Analysis (PCA), while the validation models resulted from nineteen samples that were not included in the calibration set. The and stability of calibration models were evaluated by coefficient of determination for calibration (R2cal) and root mean square error of cross-validation (RMSECV). The coefficient of determination for validation (R2val) and root mean square error of prediction (RMSEP) were used for validation models. The main results showed that: (1) the predictive models from pulp were more credible in terms of the R2cal and R2val values than those from wood powder by 25 to 70%; and (2) a validation model for kappa number from pulp showed a better stability than the corresponding calibration model, since RMSEP was 23.5% less than RMSECV, while calibration models for pulp yield were more steady than validation models. This study provided reliable models for predicting kappa number and pulp yield rapidly and with a minimal need for physical sampling.

Flax shive (FS) is a byproduct from flax fiber separation. The use of absorbent prepared from chitosan-modified flax shive (CFS) has been studied for removal of reactive red dye (RR228) from aqueous solutions. CFS was characterized by the Brunauer-Emmett-Teller (BET) method, Scanning Electron Microscopy (SEM), Fourier Transform Infrared spectrometry (FTIR), and X-ray photoelectron spectroscopy (XPS). A batch adsorption study was conducted under various contact time, initial concentration, solution pH, and adsorbent dosage. It was found that the BET and Langmuir surface area of CFS were 1.772 m2 g-1 and 3.057 m2 g-1, respectively. Results showed that CFS has the same pores as FS and that the –NH2 group on CFS is the main adsorption site for dye sorption. Equilibrium adsorption capacity could be reached within 480 min, and RR228 uptake was satisfactory at a pH of 2.0. The percentage removal were 100%, 100%, 90%, and 85% at pH 2.0 under dye concentrations of 10 mg/L, 20 mg/L, 30 mg/L, and 40 mg/L, respectively. The adsorption accurately fitted a pseudo-second-order kinetic model and a Langmuir isotherm model. It is proposed that CFS could be applied as a low-cost absorbent in removal of dyes from wastewater.

Commercial bamboo chips were evaluated as raw material for dissolving pulp production. The chips were auto-hydrolyzed (AH) and subsequently cooked by the NaOH/AQ process and bleached to full brightness with the O-CCE-D-(EP)-D-P sequence. The term CCE designates a cold caustic extraction stage. The bamboo chip chemistry (22.4% lignin, 19.5% xylans, 49.3% cellulose, 16.8% total extractives, and 1.5% ash) was apparently unfavorable; however high quality dissolving pulp was produced using the aforementioned technologies, even when compared to results obtained with traditional eucalypt commercial wood chips. The pulp showed high brightness (92.4 % ISO) and α-cellulose content (94.9%). Its contents of hemicelluloses, extractives and ash were within acceptable levels for a dissolving pulp aimed at viscose rayon production. Thus, the bamboo chip furnish investigated can be regarded as a viable raw material for dissolving pulp production.