酒石酸强化重金属复合污染模拟土壤电动修复过程及机理分析

Process and mechanism analysis on tartaric acid enhanced electrokinetic remediation of simulated heavy metal combined contamination soil

为提高电动修复重金属复合污染土壤的效率,通过配制重金属复合污染模拟土壤,构建电动修复实验装置,利用2因素完全随机实验设计研究了酒石酸浓度和时间对重金属去除效果的影响;采用BCR法对土壤金属赋存形态进行了分析表征。结果表明:与对照相比,以酒石酸为电解液显著提高了重金属的去除率;重金属去除率受酒石酸浓度和修复时间影响显著;以0.05 mol·L^-1酒石酸为电解液修复120 h后,重金属去除效果最好,重金属总去除率为86.15%,Cu^2+、Mn^2+、Cd^2+、Pb^2+、Zn^2+的去除率分别为75.67%、98.11%、85.1%、70.75%和90.9%。BCR分析表明,酒石酸有助于提高土壤中弱酸提取态重金属含量,提高了重金属的迁移性能,从而有利于电动修复过程。

In order to improve the efficiency of electrokinetic remediation of heavy metal combined contamination soils,the corresponding experimental device was constructed to conduct the electrokinetic remediation of simulated soil,the effects of tartaric acid concentration and time on the removal efficiency of heavy metals were studied through two-factor completely random experimental design.The occurrence forms of metals in soils were analyzed and characterized by BCR method.Results showed the heavy metal removal efficiency was significantly improved with the tartaric acid electrolyte compared to the control.The heavy metal removal efficiency was significantly influenced by the tartaric acid concentration and remediation time.The optimized removal efficiency was achieved after 120 h electrokinetic remediation when 0.05 mol·L^-1 tartaric acid electrolyte was used,the total removal efficiency of the metals was 86.15%,and the removal efficiencies of Cu,Mn,Cd,Pb and Zn were 75.67%,98.11%,85.1%,70.75%and 90.9%,respectively.BCR analysis results showed that the tartaric acid could improve the fraction of acid extractable state metal in the soil,the immigration capacity of the heavy metal was improved which was benefit for the electrokinetic remediation process.