Remediation of heavy-metal-contaminated soil using chelant extraction: Feasibility studies

摘要

Results are presented of a laboratory investigation conducted to determine the efficacy of using chelating agents to extract heavy metals (Pb, Cd, Cr, Ba, Cu, and Zn) from soil, the primary focus being on the extraction of lead from the soil. Results from the batch-shaker studies and emphasizes the columnar extraction studies are described. The chelating agents studied included ethylenediaminetetraacetic acid (EDTA) and citric acid, in addition to water. Concentrations of the chelants ranged from 0.01 to 0.05 M; the suspension pH was varied between 3 and 8. Results showed that the removal of lead using citric acid and water was somewhat pH-dependent. For the batch-shaker studies, the results indicated that EDTA was more effective at removing Cd, Cu, Pb, and Zn than was citric acid (both present at 0.01 M). EDTA and citric acid were equally effective in mobilizing Cr and Ba from the soil. Heavy metals removal was slightly more effective in the more acidic region (pH (le) 5).