EDTA强化电动力学修复重金属复合污染土壤

在自制的电动力学装置中,研究多种重金属复合污染土壤的电动力学修复,通过在阴极添加络合剂EDTA来提高修复效率。实验结果表明,EDTA的引入提高了修复过程中的电流值,且EDTA与重金属的络合提高了污染物向电极液的迁移效率,从而强化了电动力学修复效果。在设定的浓度(0、0.01、0.02、0.05和0.1 mol/L)中,0.1 mol/L的EDTA具有最佳的修复效率。在此实验条件下,污染土壤中的总铜、总铅和总镉的去除率分别为90.2%、68.1%和95.1%。电动力学修复后,对土壤重金属进行化学形态分析,发现电动力学修复显著改变了土壤重金属存在形态,修复后土壤中的铜、铅、镉主要以较稳定的有机态和残余态形式存在,显著降低了对周边生物和环境的毒害。

EDTA-enhanced electrokinetic remediation of heavy metals co-contaminated soil

A series of EDTA-enhanced electrokinetic remediation of multi-metals co-contaminated soil were studied in a self-made electrokinetic apparatus.Experimental results showed that EDTA increased the removal efficiency of heavy metals from contaminated soil,because it enhanced electrical current and the migration of heavy metals to the electrolyte by the complexation of EDTA with heavy metals.0.1 mol/L EDTA was found to be the best concentration for metal removal in all tested concentrations (0,0.01,0.02,0.05 and 0.1 mol/L) under the chosen experimental conditions.About 90.2% of total Cu,68.1% of total Pb,95.1% of total Cd were removed from contaminated soil by electrokinetic remediation at the 0.1 mol/L EDTA concentration.Chemical speciation analysis of heavy metals in the soil showed that electrokinetic remediation had a significant impact on changes in partitioning of heavy metals.After electrokinetic treatment,Cu,Pb and Cd in the treated soil were mainly found in relatively stable fraction (organic fraction and residual fraction),and their toxic effects to the organism and environment were reduced.