铅污染土壤电动修复增强技术的研究

利用电动修复技术对铅污染土壤的修复进行了实验室研究,研究了修复时间和络合剂EDTA对电动修复效果的影响,分析了土壤重金属的迁移和变化特征。结果表明,在电场力作用下随着修复时间的增长污染物的去除率相应提高,去除率由修复时间5 d时的13%增加到15 d时的20%。以EDTA作为阴极控制液,EDTA可与硝酸铅反应形成溶解态的络合物,提高铅离子的移动性,从而提高修复效果。随着EDTA浓度由0.1 mol/L到0.2 mol/L,Pb的去除率由44.4%提高到61.5%,说明添加络合剂可以提高修复效果。另外,电动修复效果与铅的形态分布有密切关系,交换态和碳酸盐结合态有利于重金属铅的去除。

Experimental study on enhancement technology for electrokinetic remediation of lead contaminated soil

Lab-scale electrokinetic remediation of Pb-polluted soil was studied to investigate the effect of remediating time and complexant EDTA on the Pb removal efficiency.The Pb distribution and migration characteristic and mechanism during remediation were analyzed as well.Results indicated that the removal efficiency increased with the increasing duration of the treatment,i.e.,from 13% in 5 days to 20% in 15 days.When EDTA was added to the catholyte,EDTA could dissolve insoluble Pb in soils to form soluble Pb-EDTA complexes,increasing Pb mobility and accordingly removal efficiency.The removal efficiency was enhanced from 44.4% to 61.5% when the EDTA concentration increased from 0.1 mol / L to 0.2 mol / L,showing that EDTA played an important role in remediation.In addition,the efficiency of electrokinetic remediation was closely related to the distribution forms of Pb,the two forms which exchangeable and carbonates-bounded were conducive to the removal of Pb.