Characterization of Carboxymethyl Cellulose Made from Bamboo Harvesting Residues

Bamboo harvesting residues are wastes by-products of bamboo industries that contain holocellulose for about 63.14%to 70.71%,which often be discarded,incinerated or buried.In this study,carboxymethyl cellulose was prepared from bamboo harvesting residues(bamboo-branch and bamboo-tip)as raw materials.The chemical composition of bamboo harvesting residues,the viscosity and degree of substitution of carboxymethyl cellulose were determined.Carboxymethyl cellulose obtained was further characterized and compared by means of FTIR,SEM,XRD and TG.Results showed that under the optimized identical conditions,the viscosity and degree of substitution of carboxymethyl cellulose from bamboo-branch and bamboo-tip were 6.0 and 78.9 mPa·s,0.75 and 0.89,respectively.Carboxymethyl cellulose obtained from bamboo-tip displayed a lower crystallinity and a better thermal stability as compared to synthetic carboxymethyl cellulose obtained from bamboo-branch and bamboo-culm.

Optimization for microwave-assisted direct liquefaction of bamboo residue in glycerol/methanol mixtures

Bamboo residues were liquefied in a mixture of glycerol and methanol in the presence of sulfuric acid using microwave energy. We investigated the effects of liquefaction conditions, including glycerol/methanol ratio, liquefaction temperature, and reaction time on the conversion yield. The optimal liquefaction conditions were under the temperature of 120 °C, the reaction time of 7 min, the glycerol–methanol–bamboo ratio of 8/0/2（W/W）, and the microwave power of 300 W. Maximum conversion yield was 96.7 %. The liquid products were separated into two contents（water soluble part and precipitate part） by addition of a sufficient amount of water. By Fourier transform infrared（FT-IR）, the water soluble content mainly contained glycerol and its derivate and carbohydrate degradation products, and the precipitate content was mainly lignin derivatives.

Environmental behaviors of phoxim with two formulations in bamboo forest under soil surface mulching

Phoxim（emulsifiable concentrate（EC） and granules（G）） has been widely used in bamboo forests. The persistence and magnitude of phoxim residues in the crop and soil must be investigated to ensure human and environmental safety. The environmental behaviors of the two formulations were investigated in a bamboo forest under soil surface mulching conditions（CP） and non-covered cultivation conditions（NCP）. The half-lives of phoxim in soil under the two conditions in soil were 4.1–6.2 days（EC） and 31.5–49.5 days（G）,respectively. Phoxim in EC could be leached from the topsoil into the subsoil. A minimized leaching effect was observed for G under NCP. Inversely, an enhanced leaching effect was observed for G under CP. The G formulation resulted in more parent compound（in bamboo shoots） and metabolite（in soil） residues of phoxim than in the case of EC, especially under CP conditions. In addition, the intensity and duration of the formulation effect on soil p H adjustment from G were more obvious than that from EC. Results showed that the environmental behaviors（distribution, degradation, residue） of phoxim in the bamboo forest were significantly influenced by the type of formulation. The prolongation effect from phoxim G might cause persistence and long-term environmental risk. However,bamboo shoot consumption could be considered relatively safe after applying the recommended dose of the two phoxim formulations.