【摘要】 针对淋洗可能导致土壤残留重金属活化问题,研究淋洗/钝化联合修复对重金属污染土壤风险的削减作用。以乙二醇双（2-氨基乙基醚）四乙酸[ethylenebis （oxyethylenenitrilo） tetraacetic acid,EGTA]为淋洗剂,以重过磷酸钙（triple super phosphate,TSP）为钝化剂,研究了EGTA投加量、液固比、淋洗时间和TSP投加量等对模拟重金属污染黄棕壤中Cu、Zn、Pb和Cd 4种重金属洗脱率和浸出浓度的影响,通过响应面法设计多因素实验,拟合了土壤重金属环境风险削减率与EGTA投加量、液固比及TSP投加量之间的关系,采用涵盖土壤重金属含量、浸出浓度和毒性的土壤重金属环境风险评价方法对修复效果进行评价。结果表明,EGTA对Cu和Cd的洗脱率较高,可显著降低Zn和Cd浸出浓度。增加淋洗时间有助于提高Cu、Zn和Cd洗脱率并降低其浸出浓度,但提高了Pb浸出浓度。随着液固比的增加,Zn和Pb洗脱率呈上升趋势,Cd洗脱率呈下降趋势,Cu洗脱率先提高后下降;Cu、Zn和Cd浸出浓度呈下降趋势,而Pb浸出浓度呈上升趋势。TSP钝化大幅度削减了Pb浸出浓度。总环境风险削减率（β）与EGTA投加量、液固比及TSP投加量呈二次方关系,当EGTA投加量为1.0 g·L^-1,液固比为10,TSP投加量w为2%时,β为62.80%,与验证实验结果相近,表明模型具有较好的模拟和预测能力。提高EGTA投加量和液固比可以大幅度降低Cu、Zn和Cd的环境风险,TSP钝化处理对Pb环境风险的削减作用较好,EGTA投加量与液固比以及EGTA投加量与TSP投加量对β表现为协同作用。更多还原

【Abstract】 Considering that chelant-enhance washing may increase the activity of residual metals in soil, the risk reduction of heavy metal-contaminated soil by integrated soil washing with immobilization was investigated. Ethylenebis（oxyethylenenitrilo） tetraacetic acid（EGTA） and triple super phosphate（TSP） were used as washing and stabilization agent, respectively, to remediate Cu-, Zn-, Pb-and Cd-contaminated yellow brown soil. The effects of EGTA dosage, washing time, liquid-to-solid ratio and TSP dosage on heavy metal removal rate and leaching concentration were explored. The relationship between the environmental risk reduction rate and EGTA dosage, liquid-to-solid ratio and TSP dosage was fitted by response surface method（RSM）. The remediation performance was evaluated by the environmental risk assessment method involving heavy metal content in soil, leaching concentration and toxicity. The results show that with EGTA enhanced-washing, the elution rate of Cu and Cd was relatively higher and the leaching concentration of Zn and Cd was significantly reduced. By increasing the washing time, the removal rate of Cu, Zn, Cd was improved, while the leaching concentration declined. However, the leaching concentration of Pb was increased. With the increase of liquid-to-solid ratio, the removal rate of Zn and Pb was increased, while that for Cd was decreased and for Cu was firstly increased and then decreased. Meanwhile, the leaching concentration of Cu, Zn and Cd was decreased while for Pb was increased. The leaching concentration of Pb was significantly reduced by the passivation of TSP. The total environmental risk reduction rate（β） had a significant quadratic relationship with the EGTA dosage, liquid-to-solid ratio and TSP dosage. The model results are similar to the verification experiment results when the liquid-to-solid ratio, EGTA, TSP and β were 10, 1.0 g·L^-1, 2% and 62.80%, respectively, which indicate that the model has good simulation and prediction ability. The environmental risk of Cu, Zn, and Cd could be significantly reduced by increasing the EGTA dosage and liquid-to-solid ratio. The passivation of TSP possessed a positive effect on the environmental risk reduction of Pb. In addition, the synergistic effect on β was observed between EGTA dosage and liquid-to-solid ratio, as well as EGTA and TSP dosage.更多还原