This research presents the optimization of soil washing conditions in the removal of multiple heavy metals (Cu-Pb-Zn-Cd) under the using of ethylenediaminetetraacetic acid (EDTA). The optimum combination of washing parameters in a bench-scale soil washing experiments is determined by response surface methodology (RSM). Central composite design is applied after single factor experiment, EDTA concentration, solid-to-liquid ratio and washing time are evaluated variables for the removal processes, and the regression models of HMs are constructed. The results show that, EDTA concentration and solid-to-liquid ratio are significant factors for this process. Subsequently, 50% of Cu removal was set as the optimum target to optimize the combined conditions, through the building of multiple quadratic regression models, the optimal condition combination is determined that EDTA concentration is 0.0026 mol·L-1, solid-to-liquid ratio is 1:22, washing time is 3.89 h, the extraction rate of Pb, Zn, Cd is predicted to be 78%, 75% and 71%, respectively.

中文翻译：

---

使用响应表面方法去除多种重金属的 EDTA 增强土壤洗涤的优化

本研究介绍了使用乙二胺四乙酸 (EDTA) 去除多种重金属 (Cu-Pb-Zn-Cd) 的土壤洗涤条件的优化。实验室规模土壤洗涤实验中洗涤参数的最佳组合由响应面方法 (RSM) 确定。单因素试验后采用中心复合设计，以EDTA浓度、固液比和洗涤时间作为去除过程的评价变量，构建HMs的回归模型。结果表明，EDTA浓度和固液比是该过程的重要因素。随后，通过建立多元二次回归模型，以50%的Cu去除率作为优化组合条件的最佳目标，