EDTA-enhanced electroremediation of metal-contaminated soils

Precipitation and sorption of heavy metals reduce their mobility and limit the effectiveness of in-situ remediation technologies. In electroremediation, metal mobility can be further impeded by the development of regions of elevated pH near the collecting electrodes. This paper investigates the feas...

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Bibliographic Details
Published in:Journal of hazardous materials 1997-08, Vol.55 (1), p.61-79
Main Authors: Wong, Joseph S.H., Hicks, R.Edwin, Probstein, Ronald F.
Format: Article
Language:English
Subjects:
EDTA
Electroremediation
Heavy metals
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Summary:Precipitation and sorption of heavy metals reduce their mobility and limit the effectiveness of in-situ remediation technologies. In electroremediation, metal mobility can be further impeded by the development of regions of elevated pH near the collecting electrodes. This paper investigates the feasibility of mobilizing precipitated heavy metals by delivering complexing agents into soils by ionic migration. Two metals, lead and zinc, were selected as contaminants, and EDTA, a widely available non-toxic chelating agent, was selected as the complexing agent. It was found that EDTA added to the catholyte can be readily delivered into a sandy soil where it solubilizes the precipitated metals. The resulting complexes are then transported to the anode with metal removal efficiencies, for the spiked laboratory samples, approaching 100%. The poor ligand utilization obtained in the tests is attributed to the low dissolution rate of the metals. Modifying the operating conditions to increase the concentration and the residence time of the ligand in the soil is expected to improve the utilization efficiency of the complexing agent.
ISSN:0304-3894
1873-3336
DOI:10.1016/S0304-3894(97)00008-3