Removal of heavy metals (Cu, Cd and Zn) from contaminated soils using EDTA and FeCl3

Environmental pollution caused by heavy metals from different industrial activities constitutes a serious risk for the environment. Soils contaminated with metals, such as Cu, Cd and Zn, are often subjected to physical or chemical remediation procedures to purify soils from these metals. Typical chelating agents used for metal extraction and soil washing generally include ethylene-diaminetetraacetic acid nitrilotriacetic acid, diethylenetriaminepentaacetic acid and citric acid. The subject study evaluating the potential of soil washing methods using EDTA and ferric chloride on two types of soils (coarse grained, fine grained). The effects of operating parameters, such as liquid/solid ratio, soil washing chemicals and washing time were examined. In extraction procedure of Cd (266 mg kg^-1), Cu (194 mg kg^-1) and Zn (497 mg kg^-1) from contaminated coarse grained soil with using 0.01 M FeCl₃ washing solution (liquid/solid ratio 20) for 2 hours, contaminants were removed 96.66%, 90.02% and 98.25%, respectively. In extraction procedure of Cd (218 mg kg^-1), Cu (153 mg kg^-1) and Zn (441.6 mg kg^-1) from contaminated fine grained soil with using 0.01 M FeCl₃ washing solution (liquid/solid ratio 20) for 2 hours, contaminants were removed 98.18%, 97.48% and 98.05%, respectively. Better removal efficiencies have been obtained by using FeCl₃. These results confirmed the effectiveness of the soil-washing method with FeCl₃ in remediating heavy metals (Cu, Cd and Zn) from different types of soil.