铬污染土壤的电动修复研究

Electrokinetic Remediation of Chromium Contaminated Soil

通过调控电动修复阴极pH值及添加增强剂,提升电动修复技术对Cr污染土壤的总Cr去除率,并探究了电动修复工程的能耗变化及Cr迁移分布规律。结果表明,乙二胺四乙酸(EDTA)、柠檬酸和盐酸等增强试剂能显著提升电动修复过程的总Cr去除率。不调控电动修复阴极pH值,电动修复土壤7d,向土壤分别添加EDTA、柠檬酸时,总Cr去除率分别为24.47%、23.24%;不调控阴极pH值,会发生较明显的偏极效应。控制电动修复阴极pH值,电动修复土壤7d,向土壤分别添加盐酸、柠檬酸时,总Cr去除率分别为44.20%(是空白电动修复组的4.9倍)、36.80%;控制阴极pH值,能有效阻止阴极区域Cr发生沉淀作用,提高Cr的去除率;控制阴极pH值不会显著增加电动修复过程能耗。该方法大幅提升了电动修复对土壤中总Cr的去除率,对重金属污染土壤的修复具有指导意义。

By adjusting the pH value of electrokinetic remediation cathode and adding enhancers,the total removal rate of Cr from the contaminated soil by electrokinetic remediation technology was increased.Then,the change of energy consumption and law of Cr migration and distribution during the electrokinetic remediation project were explored.The results show that EDTA,citric acid and hydrochloric acid can significantly enhance the total Cr removal rate during the electrokinetic remediation process.The total removal rates of Cr were 24.47%and 23.24%respectively after 7 days of electrokinetic remediation without adjusting the pH value of the cathode,by adding EDTA and citric acid into the soil.The pH value of the cathode isn′t adjusted,which results in an obvious polarization effect.In contrast,the total removal rates of Cr were 44.20%(4.9 times as much as the blank)and 36.80%,respectively,after 7 days of electrokinetic remediation with the pH value of the cathode controlled,by adding hydrochloric acid and citric acid to the soil,respectively.Controlling the pH value of the cathode can effectively prevent the precipitation of Cr in the cathode region,thus enhancing the removal rate of Cr,but won′t significantly increase the energy consumption of the electrokinetic remediation process.This method can greatly increase the total removal rate of Cr in contaminated soil by electrokinetic remediation,which is of significance in guiding the remediation of heavy metal contaminated soil.