不同螯合剂对两类Cd和Ni污染土壤的淋洗修复对比

选择了2种生物可降解螯合剂柠檬酸(CA)和谷氨酸N, N-二乙酸(GLDA)与常规淋洗剂乙二胺四乙酸(EDTA)对矿区重金属污染黄棕壤和红壤进行化学淋洗实验, 对比不同淋洗剂对不同类型土壤中Cd、Ni的去除效果, 以及不同淋洗处理对2类土壤中残留重金属的形态分布、潜在环境风险及土壤酶活性的影响.结果表明: EDTA和GLDA对2类土壤中重金属均有较好的淋洗效果, 在降低土壤内残留重金属迁移性和生物可利用性方面能力相似, 但GLDA和CA淋洗后对土壤酶活性不利影响显著低于EDTA淋洗, 综合考虑淋洗效率和生态安全, 在重金属污染的酸性土壤中GLDA可作为常规淋洗剂EDTA的良好替代物.

Leaching remediation efficiency of biodegradable chelating agents for the Cd and Ni contaminated soils

For assessing leaching remediation efficiency of different biodegradable chelating agents for remediating heavy metals-contaminated soils, Citric acid (CA), DL-2-(2-carboxymethyl) nitrilotriacetic acid (GLDA)(biodegradable chelating agents) and Ethylenediaminetetraacetic acid (EDTA) (a conventional leaching agent as a check) with different leaching treatments were applied to evaluate the removing efficiency of Cd and Ni from yellow brown soil and red soil that have been highly contaminated with various heavy metals in two mining areas. Our experimental results demonstrate higher efficiencies of both EDTA and GLDA for removing Cd and Ni from these soils comparing with CA to reduce the mobility and bioavailability of soil heavy metals. However, the adverse effects of GLDA and CA leaching remediation on soil enzyme activity are significantly lower than that of EDTA leaching remediation. In view of both leaching efficiency and ecological safety, our study has confirmed that GLDA can be used as a good substitute for the conventional leaching agent EDTA in the acidic soils contaminated with heavy metals.