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.
Huan Jing Ke Xue. 2023 Mar 8;44(3):1668-1677. doi: 10.13227/j.hjkx.202204269.
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, Fe(NO), KCl, KNO, and HCl solutions were selected, and the effects of Fe, 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, K, H, and Cl had different effects on the four heavy metal removals; for Cd and Zn, the removal effect of Hwas the most effective, but for Pb and Cu, the effect of Fe was the most obvious. On the whole, FeCl and Fe(NO) showed 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 and Fe(NO), the HCl solution had a moderate removal effect on the four heavy metals in the soil, and the neutral salts KCl and KNO had little removal effect on the four heavy metals. Especially for Cd and Cu, KCl and KNO 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.
在本研究中，采用化学淋洗和电动技术修复重金属污染土壤，以阐明其有效性和作用机制。选择了FeCl、Fe(NO)、KCl、KNO和HCl溶液作为化学淋洗剂，比较分析了Fe、K、H和Cl对四种重金属（Cd、Pb、Cu和Zn）去除效果的影响。然后，研究了化学淋洗后土壤中重金属形态对电动修复效率的影响。结果表明，Fe、K、H和Cl对四种重金属的去除效果不同；对于Cd和Zn，H的去除效果最显著，但对于Pb和Cu，Fe的效果最明显。总体而言，FeCl和Fe(NO)对Cd、Pb和Cu的去除效果最佳。对于土壤中Zn的去除，五种淋洗剂的去除效果差异不明显。与FeCl和Fe(NO)相比，HCl溶液对土壤中四种重金属的去除效果适中，中性盐KCl和KNO对四种重金属的去除效果较小。特别是对于Cd和Cu，添加KCl和KNO显著提高了后续电动修复对重金属的去除效果。化学淋洗后，电动修复可使表层土壤（0-10 cm）中的重金属向下迁移并富集在10-20 cm和20-30 cm土层中，这一问题有待进一步研究解决。
