Soil washing has been verified as a feasible technology for source reduction for contaminated soil with heavy metals. We conducted batch and column leaching experiments to investigate the removal of Cd, Pb, Cu and Zn from smelter soil by citric acid. The removal efficiency of heavy metals by batch leaching reached a maximum (89.1% Cd, 26.8% Pb, 41.7% Zn, 14.2% Cu) at a concentration of 0.1 M and a pH of 5. Citric acid also removed 91.3%, 11.1%, 39.2% and 11.1% of Cd, Pb, Zn, and Cu respectively after column leaching. Citric acid mainly removed exchangeable, carbonate bound and oxide bound Cd, Pb, Cu and Zn fractions. Vertical distributions of Cd, Cu and Zn similarly increased with increasing soil depth. Chestnut shells were applied to the recovery of citric acid from the waste eluent, which removed 84.4%, 97.5%, 74.6%, 70.3% of Cd, Pb, Zn, and Cu, respectively, due to chestnut shell chelation. Fresh and regenerated citric acid was used in batch leaching of heavy metal-contaminated soil, and they showed similar ability to extract heavy metals.

中文翻译：

---

柠檬酸浸出法去除冶炼厂土壤中的Cd，Pb，Zn，Cu。

土壤清洗已被证明是减少污染重金属土壤的可行技术。我们进行了分批和柱浸实验，研究了柠檬酸从冶炼厂土壤中去除Cd，Pb，Cu和Zn的方法。在0.1 M的浓度和pH值为5的情况下，通过分批浸出的重金属去除效率达到最大值（89.1％Cd，26.8％Pb，41.7％Zn，14.2％Cu），柠檬酸也去除了91.3％，11.1％柱浸后，Cd，Pb，Zn和Cu的含量分别为39.2％和11.1％。柠檬酸主要去除可交换的，碳酸盐结合的和氧化物结合的Cd，Pb，Cu和Zn馏分。镉，铜和锌的垂直分布也随着土壤深度的增加而增加。栗壳用于回收废洗脱液中的柠檬酸，去除了84.4％，97.5％，74.6％，70.3％的Cd，Pb，Zn和Cu，分别由于栗壳的螯合。新鲜和再生的柠檬酸用于重金属污染土壤的分批浸提，它们具有相似的重金属提取能力。