土壤中铬电动修复过程及影响因素

Process and influence factors of electro-kinetic remediation of chromium contaminated soil

实验筛选出阳极pH、阴极pH、电压梯度、电极形状4种影响因素,以黏土为研究对象,设计正交实验和对比实验研究铬的电动修复过程。结果表明,最重要的影响因素为电压梯度,其他影响因素重要性排序为阳极pH、阴极pH、电极形状;在电压梯度为1.5 V·cm^(-1)下,以去离子水作为电解质,分别控制阴极和阳极pH在11和3,取得很好的去除效果,144 h后铬迁移率达到80.9%。总铬和六价铬分布规律类似,从阳极到阴极呈现逐渐下降的趋势。经过电动修复后土壤中水溶态铬比例减少,可氧化态和残渣态比例增大。铬电动修复控制系统在微电流范围内可取得很好的去除效果。

Choosing anode pH,cathode pH,voltage gradient,and electrode shape as experimental influence factors,orthogonal and contrast tests were designed to study the process of electrokinetic remediation of chromium on clay. The results showed that voltage gradient is the most influential factor on remediation,followed by anolyte pH,catholyte pH,and electrode shape,successively. The migration of chromium reached 80. 9% after 144 h with deionized water as the electrolyte under the following conditions： catholyte pH of 11,anolyte pH of 3,and voltage gradient of 1. 5 V·cm-1. Total Cr and Cr6 ＋distributions were similar,diminishing from anode to cathode. After electrokinetic remediation,the proportion of water-soluble Cr in soil decreased while those of the oxidation state and residual state increased. The system shows very good removal efficiency in a micro electric current.