用离子交换膨胀床去除铬离子

Removal of chromium ions in an expand ion-exchange bed

含铬废水可对环境造成严重污染。为去除废水中的六价铬离子,利用自制的膨胀床,以Mp500树脂为分离介质,进行静态平衡实验,研究了初始质量浓度和pH值对于静态交换量的影响。研究了膨胀率对流出曲线的影响,并和固定床的实验结果进行了比较。实验结果表明:溶液质量浓度和pH值是静态平衡的主要影响因素,最佳的进料质量浓度为100～200mg.L-1,pH值为3～5;膨胀率随流速的增加而线性增加,膨胀率不宜超过0.3;当膨胀率较小时,膨胀床的处理效果优于固定床。

Wastewater containing chromium is a major source of environmental pollution. This paper analyzes the removal of hexavalent chromium from wastewater using an ionexchange bed with the strongly basic ion exchange resin Mp500. Static adsorption was first studied to determine the initial concentration and pH of the feed stream. Then, the influence of the expansion ratio on the outflow curve was studied. Finally, the expand bed was compared with the traditional fixed bed in terms of the ionexchange adsorption. The results show that the ion exchange process is greatly influenced by the initial concentration and pH of the feed flow with the best feed conditions being a concentration of 100～200 mg·L-1 and pH 3～5. The expansion ratio increases linearly with flow velocity with a maximum expansion ratio of less than 0.3. All of the expand beds provide better adsorption than the fixedbed.