亚氨基二琥珀酸修复重金属污染土壤及环境风险削减评估

以亚氨基二琥珀酸（ISA）为洗脱剂，考察ISA投加量、洗脱液pH值、反应时间和土液比对Cd、Pb和Zn去除率影响，通过Box-Behnken多因素设计法优化最佳洗脱条件，并采用涵盖土壤重金属残留量、浸出浓度和毒性的综合环境风险法评估修复效果.结果表明，ISA对Cd、Pb和Zn去除率随其浓度增加而增加；ISA浓度为50mmol/L时，对矿山污染土壤中Cd、Pb和Zn去除率达到11.83%、34.26%和20.96%；对污染农田土壤中Cd、Pb和Zn去除率达到48.89%、57.08%和81.80%.增加反应时间和洗脱液酸性有助于提高ISA对Cd、Pb和Zn去除率.随土液比减低，Cd、Pb和Zn去除率呈上升趋势.ISA去除Cd、Pb和Zn最佳条件为：ISA浓度70mmol/L、洗脱液pH4.0和反应时间120min，预测矿山土壤和污染农田土壤中Cd、Pb和Zn总去除率最大分别为32.58%和93.16%.ISA大幅度降低水溶态、可交换态和碳酸盐结合态Cd、Pb和Zn残留量，从而削减矿山土壤和污染农田土壤中Cd、Pb和Zn总环境风险达50.81%和87.13%.亚氨基二琥珀酸可有效去除污染土壤中重金属并降低残留重金属的环境风险，是一种潜在材料可用于土壤重金属污染修复.

Remediation of heavy metal contaminated soil by iminodisuccinic acid and assessment of environmental risk reduction

Iminodisuccinic acid (ISA) was used as a washing agent to remove Cd, Pb, and Zn from polluted soil under the action of ISA concentration, pH, washing time, and soil-liquid ratio. A three-factor and three-level optimization model based on the Box-Behnken design method were established to determine the optimum washing conditions. The comprehensive environmental risk method involving the residual content, leaching concentration, and toxicity of heavy metals in soil was used to evaluate the washing remediation performance. Cd, Pb and Zn removal efficiencies increased with the increase of ISA concentration. They reached 11.83%, 34.26%, and 20.96% in mine soil and 48.89%, 57.08%, and 81.80% in polluted farmland soil, respectively, at the ISA concentration of 50mmol/L. By increasing contact time and the acidity of the washing solution, the Cd, Pb and Zn removal efficiencies were improved. They increased as the soil-liquid ratio decrease. The predicted maximum total removal rates of heavy metal in mine soil and contaminated farmland soil reached 32.58% and 93.16%, respectively, under the optimized conditions of ISA concentration of 70mmol/L, pH of 4.0, and reaction time of 120min. Under this condition, the surplus of heavy metal in the water-soluble, exchangeable, and carbonate bounding states decreased significantly, thus reducing the total environmental risks of heavy metal in mine soil and contaminated farmland soil by 50.81% and 87.13%. Iminodosuccinic acid could effectively remove heavy metals from contaminated soil and reduce the environmental risks of residual heavy metals and is a potential material for remediation of heavy metal-contaminated soil.