利用EDTA溶液淋洗修复重金属污染土壤

Heavy Metal Removal in Contaminated Soil with EDTA Leaching

通过室内模拟实验,采用振荡淋洗的方法研究了不同浓度、pH值、淋洗时间的EDTA溶液对污染土壤中Pb、Cu、Ni、Zn、Cr的去除,并利用一级反应动力学模型对实验数据进行拟合。结果表明:在实验条件下,EDTA为0.05mol/L、pH值=7、液土比为10颐1、淋洗时间为18h的条件下能达到对污染土壤重金属最大去除率,去除率分别为Zn85.26%、Cu21.65%、Pb16.76%、Ni7.83%、Cr6.29%。模型拟合结果表明,转移系数最大的是Cr,其次是Cu、Pb、Zn,最后是Ni,说明在土壤淋洗过程中Cr最先达到质量转移的平衡状态,然后是Cu、Pb、Zn,最后是Ni。

This paper reported the feasibility of remediation of heavy metal contaminated soil with EDTA. Batch experiments were performed to test the influence of EDTA concentration, pH and reaction time. An empirical model was employed to describe the kinetics of heavy metal dissolution and desorption. The results showed that utilization of EDTA is effective for removal of heavy metal from contaminated soil within 18h, attaining 85.26% of Zn, 6.29% of Cr, 7.64% of Pb, 21.53% of Cu, 8.01% of Ni in the 0.05M, pH=7.0 of EDTA, ratio of liquid and solid=10：1.The mass transfer coefficient was in the order of Cr〉 Cu 〉 Pb 〉Zn〉Ni.