复合药剂结合底部真空淋洗修复Cu污染土试验研究

Experimental Study on Remediation of Cu-contaminated Soil Combined with Bottom Vacuum Leaching

摘要:

提出将乙二胺四乙酸二钠 （EDTA - 2Na） 与柠檬酸 （CA） 复配并结合底部真空淋洗的改进修复技术。通过针对五种不同复配比淋洗药剂的室内底部真空淋洗模型试验，研究淋洗后土壤重金属去除率、pH 值及岩土工程参数变化。结果表明，该复配淋洗对 Cu 污染土修复效果显著优于单一药剂淋洗，去除率最高达 98% 。通过 CA 增强 EDTA - 2Na 溶解性，提升污染物去除率，减少各自用量，避免土壤二次污染。复配比变化对土壤含水率、黏粒含量及液塑限、比重、容重参数影响显著。

Abstract:

An improved remediation technology is proposed， which involves the combination of disodium ethylenediaminetetraacetate （EDTA-2Na） and citric acid （CA） in a complex and the use of bottom vacuum leaching. Through indoor bottom vacuum leaching model tests on five different complex-ratio leaching agents， the changes in soil heavy metal removal rate， pH value， and geotechnical engineering parameters after leaching were studied. The results show that complex leaching has a significantly better remediation effect on Cu-contaminated soil than single-agent leaching， with the highest removal rate reaching 98%. The solubility of EDTA-2Na is enhanced by CA， which improves the pollutant removal rate and reduces the dosage of each agent， thus avoiding secondary soil pollution. The change in the complex ratio has a significant impact on soil moisture content， clay content， liquid plastic limit， specific gravity， and unit weight parameters.