米糠和麦麸对水中Cr(VI)的吸附研究

BIOSORPTION STUDY OF CR(VI) FROM AQUEOUS SOLUTIONS BY RICE BRAN AND WHEAT BRAN

以米糠(RB)和麦麸(WB)作吸附剂对水中Cr(VI)的去除进行了试验研究。考察了吸附时间、初始浓度、吸附剂量、pH和粒径对吸附量的影响。当pH为1.0时,二者对Cr(VI)的吸附量均达到最大;Cr(VI)的去除随RB粒径增大而减小,随WB粒径增大而增大;RB对Cr(VI)的吸附遵循Freundlich等温线,而WB对Cr(VI)的吸附则遵循Langmuir等温线,二者对Cr(VI)的吸附都更符合拟二级动力学模型,热力学参数说明吸附过程是自发进行的吸热反应。试验结果表明RB和WB是两种有效去除废水中Cr(VI)的生物吸附剂,相比之下WB的效果更好。

This paper reports the research findings of a laboratory-based study on the removal of Cr（Ⅵ） from aqueous solution using rice bran and wheat bran as biosorbents.The effects of various parameters like contact time, initial concentrations, sorbent dose,pH and particle size were investigated. Cr（Ⅵ） removal was found to 19o maximum at pH1.0.The amount of Cr（Ⅵ） adsorbed increased with decreasing RB＇ particle size and increasing WB＇ particle size.The Langmuir and Freundlich adsorption models were used to represent the experimental data and equilibrium data fitted well to Freundlich and Langmuir isotherm model for RB and WB,respectively. Pseudo- second-order model was found to explain the kinetics of Cr（Ⅵ） adsorption most effectively.The thermodynamic parameters indicated that the adsorption reaction is endothermic and spontaneous.The results showed that rice bran and wheat bran are suitable for development of efficient biosorbents for the removal of Cr（Ⅵ） from wastewater,furthermore wheat bran is better.