抗坏血酸与柠檬酸对尾矿Pb污染土壤电动修复的强化效果

为研究抗坏血酸与柠檬酸作为增强试剂对高酸性缓冲能力的尾矿Pb污染土壤w（Pb）为（5491.9±24）mg/kg]电动修复的强化效果，利用0.1 mol/L柠檬酸作为阴极电解液并控制阴极pH在2~3之间，系统分析土壤饱和液中c（抗坏血酸）（0~0.4 mol/L）、修复电压梯度（1~3 V/cm）对电动修复Pb污染土壤的影响，并对土壤中Pb的存在形态进行分析.结果表明:当电动修复过程中施加电压梯度为1 V/cm、c（抗坏血酸）（0~0.4 mol/L）作为饱和液时，随着c（抗坏血酸）的增加，土壤中Pb的迁移能力随之增加，Pb的去除率得到提高.当c（抗坏血酸）达到0.4 mol/L时，土壤中Pb的去除率为36.86%；保持c（抗坏血酸）为0.4 mol/L，当施加电压梯度由1 V/cm增至2 V/cm时，土壤中Pb的去除率得到增加（最高可达87.09%），通过Pb的形态变化可知，w（弱酸提取态Pb）由初始的2.99%（1 V/cm）最大可降至0.34%（2 V/cm），w（可还原态Pb）由初始的83.86%（1 V/cm）最大降至2.94%（2 V/cm）.研究显示，当c（抗坏血酸）为0.4 mol/L、柠檬酸（作为阴极电解液）控制阴极电解室pH在2~3之间、施加电压梯度为2 V/cm时，土壤中Pb的迁移能力显著提高并达到较好的修复效果. 

Electrokinetic Remediation of Pb-Contaminated Tailing Soil with Enhancing Reagents Ascorbic Acid and Citric Acid

Abstract: We systematically studied the effects of different concentrations (0-0.4 mol/L) of ascorbic acid and voltage (1-3 V/cm) on the electrokinetic remediation of Pb-contaminated tailing soil (=(5491.9±24) mg/kg) based on the enhancing reagents ascorbic acid and citric acid. The tailing soil had the property of high acid buffer capacity, and the pH of the catholyte was controlled at 2-3 in the presence of citric acid (0.1 mol/L). The results indicated that with the increase of ascorbic acid concentration (0-0.4 mol/L), the migration ability of Pb in soil increased, and the removal rate of Pb increased in the process of electric voltage gradient of 1 V/cm. The removal rate of Pb was 36.86% when the concentration of ascorbic acid in the soil increased to 0.4 mol/L. When the applied voltage gradient increased from 1 V/cm to 2 V/cm, the removal rate of Pb in soil increased to 87.09%. The morphological changes of Pb showed w(acid extractable Pb) decreased from the initial 2.99% to 0.34%, and w(reducible Pb) increased from the initial value of 83.86% to 2.94%. When ascorbic acid (as saturated liquid) concentration was 0.4 mol/L, citric acid (as cathode electrolyte) controlled the cathode chamber pH at 2-3 and the applied voltage gradient was 2 V/cm, the migration ability of Pb in soil significantly improved. Eventually, the removal efficiency of Pb in soil was more significant.