化学淋洗联合电动技术修复重金属污染土壤的效果及其机制  

Effectiveness and Mechanisms of Chemical Leaching Combined with Electrokinetic Technology on the Remediation of Heavy Metal Contaminated Soil

作　　者：马强[1,2] 卫泽斌 吴启堂[1] MA Qiang;WEI Ze-bin;WU Qi-tang(College of Natural Resources and Environment,South China Agricultural University,Guangzhou 510642,China;School of Resource Environment and Safety Engineering,University of South China,Hengyang 421001,China)

机构地区：[1]华南农业大学资源环境学院,广州510642 [2]南华大学资源环境与安全工程学院,衡阳421001

出　　处：《环境科学》2023年第3期1668-1677,共10页Environmental Science

基　　金：广东省特支计划本土创新团队项目(2019BT02L218);广东省科技计划项目(2018B030324003)。

摘　　要：采用化学淋洗与电动技术联合修复重金属污染土壤,以明确其效果及其机制.试验选择了5种化学淋洗剂FeCl_(3)、Fe(NO_(3))_(3)、KCl、KNO_(3)和HCl溶液,分析比较Fe^(3+)、K^(+)、H^(+)和Cl^(-)对土壤中4种重金属(Cd、Pb、Cu和Zn)的去除效果,其后,对化学淋洗后的土壤进行垂直电动修复,研究化学淋洗对重金属污染土壤电动修复去除效率的影响.结果表明,Fe^(3+)、K^(+)、H^(+)和Cl^(-)对土壤中4种重金属的淋洗效果不同,对于Cd和Zn,H^(+)去除效果最好,对于Pb和Cu,Fe^(3+)去除效果最好.整体上比较,对于土壤中Cd、Pb和Cu的去除,化学淋洗剂FeCl_(3)和Fe(NO_(3))_(3)去除效果最好.对于土壤中Zn的去除,5种淋洗剂处理效果的区别不明显.HCl溶液对土壤中4种重金属去除效果差于FeCl_(3)和Fe(NO_(3))_(3)处理效果,但是好于中性盐KCl和KNO_(3)处理效果.KCl和KNO_(3)可提高后续电动修复的效率,尤以Cd和Cu最为明显,电动修复可使表层土壤(0~10 cm)重金属向下迁移,但在10~20 cm土层和20~30 cm土层产生富集,有待进一步改进.In this study,chemical leaching and electrokinetic technology were used to remediate heavy metal contaminated soil to elucidate its effectiveness and mechanisms.Chemical leaching agents of FeCl_(3),Fe(NO_(3))3,KCl,KNO_(3),and HCl solutions were selected,and the effects of Fe^(3+),K^(+),H^(+),and Cl^(-)on four heavy metal(Cd,Pb,Cu,and Zn)removals were compared and analyzed.Then,the influence of the speciation of heavy metals in soil after chemical leaching on the electrokinetic remediation efficiency was studied.The results showed that Fe^(3+),K^(+),H^(+),and Cl^(-)had different effects on the four heavy metal removals;for Cd and Zn,the removal effect of H^(+)was the most effective,but for Pb and Cu,the effect of Fe^(3+)was the most obvious.On the whole,FeCl_(3)and Fe(NO_(3))3showed the best removal effect for Cd,Pb,and Cu.For the removal of Zn from the soil,the difference in the removal effect of the five leaching agents was not obvious.In comparison with that of FeCl_(3)and Fe(NO_(3))3,the HCl solution had a moderate removal effect on the four heavy metals in the soil,and the neutral salts KCl and KNO_(3)had little removal effect on the four heavy metals.Especially for Cd and Cu,KCl and KNO_(3)addition significantly increased the removal of heavy metals through the subsequent electrokinetic remediation.After the chemical leaching,electrokinetic remediation could make heavy metals in the topsoil(0-10 cm)migrate downward and enrich the 10-20 cm and 20-30 cm soil layers,which requires further studies to resolve.

关 键 词：化学淋洗 电动修复 重金属 污染土壤 作用机制 

分 类 号：X53[环境科学与工程—环境工程]