Removal of many toxic heavy metals from contaminated soils by the addition of ethylenediamine tetraacetic acid is an effective and efficient means of remediation. However, the high cost of most chelating agents has precluded their uses in the remediation of metal contaminated sites. Electrolysis of Pb-EDTA, Cd-EDTA, Cr-EDTA, and Hg-EDTA chelates was investigated as a means by which the heavy metal can be separated from the chelating agent. This provides a separated heavy metal that can be recycled or is amenable to further treatment and disposal by more conventional technologies. Also, a reclaimed EDTA stream can be recycled to treat additional contaminated soil. The recycling of the EDTA will offset the high chemical cost and make the use of EDTA in treating metal contaminated sites more economical. The percent metal recovery for lead, chromium and mercury from their EDTA complexes was 99.7, 67.9, and 92.0 percent, respectively. Cadmium could not be recovered from its EDTA chelate. The percent EDTA recovery is equal to the percentage of metal electroplated from the complexes.
展开▼
