中空纤维膜萃取镉离子的研究

处理重金属离子水溶液是环境治理中的一个重要方面 ,应用新型膜萃取技术对去除水溶液中镉离子进行了研究。首先测定镉离子在不同萃取体系中的分配系数 ,选择合适的萃取剂 ,在中空纤维膜器中研究膜萃取去除镉离子的分离效果和传质特性 ,探讨不同装填因子、两相流速、水相初始浓度等实验条件对分离和传质的影响。实验结果表明 ,体积分数为 5 0 %的P2 0 4 正庚烷溶剂对于镉离子有较好的萃取效果。当装填因子为 0 .732 8时 ,经 33cm长的中空纤维膜器一级萃取可将溶液质量浓度由 40 0mg/L降至 0 .2mg/L以下 ,证明了膜萃取的高效性

A Treatment of Cd2+ Solution with Hollow Fiber Membrane Extraction Process

It is very important to treat the wastewater polluted by heavy metals. A study of the hollow fiber membrane extraction of cadmium from its dilute solution has been carried out. Some different extraction systems have been tested and the best one among them was chosen as the working system. Then, the effects of different package factor, two-phase flow rates, and the original concentration of the solution on the mass transfer characteristics were investigated. According to the experimental results and the requirement of the membrane extraction, the solvent of 50% di-iso-octyl phosphate and heptanes was used in the experiments. It was found that the concentration of the solution could be reduced from 400mg/L to 0.2mg/L below after once-through extraction in the hollow fiber membrane module with the length of 32cm and the package factor of 0.7328. This gives the evidence that the hollow fiber membrane extraction process is a higher-efficiency process for the wastewater treatment.