Xing Yunqing, Chen Xueming, Wang Dahui
Environmental Engineering Department, Zhejiang University, Hangzhou 310027, China.
Environ Sci Technol. 2007 Feb 15;41(4):1439-43. doi: 10.1021/es061499l.
Ion exchange is widely used for removal and recovery of Cr(VI) from wastewater. Generally, the exhausted ion exchanger is regenerated using chemicals. Although chemical regeneration is efficient, contaminants are introduced, leading to difficulty for the subsequent recovery of Cr(VI). To overcome such a problem, a new regeneration method, namely electrical regeneration, which is carried out on the principle of electrodialysis, is presented in this paper. Experimental results showed that the weak-base resin used could be effectively regenerated electrically. About 93% capacity of the resin was restored under a constant current of 0.25 A over a period of 24 h. The pure chromic acid was recovered in the anode chamber with a concentration of 5.03 g Cr(VI)/L. It was found that the weak-base resin regenerated electrically could remove Cr(VI) from wastewater as effectively as that regenerated chemically. The Cr(VI) concentration was reduced from initial 50 mg/L to lower than the detectable limit, 0.01 mg/L, after treatment.
离子交换被广泛用于从废水中去除和回收六价铬。一般来说，耗尽的离子交换剂使用化学药剂进行再生。虽然化学再生效率高，但会引入污染物，导致后续回收六价铬困难。为克服这一问题，本文提出了一种基于电渗析原理的新再生方法，即电再生。实验结果表明，所用的弱碱性树脂可通过电再生有效再生。在0.25 A的恒定电流下经过24小时，树脂约93%的容量得以恢复。在阳极室中回收了浓度为5.03 g六价铬/升的纯铬酸。结果发现，电再生的弱碱性树脂去除废水中六价铬的效果与化学再生的树脂一样有效。处理后，六价铬浓度从初始的50 mg/L降至低于可检测限0.01 mg/L。
