Remediation of metal contaminated soil by EDTA incorporating electrochemical recovery of metal and EDTA

Journal Article · Sun Oct 31 23:00:00 EST 1993 · Environmental Progress; (United States)

DOI:https://doi.org/10.1002/ep.670120409· OSTI ID:7063906

Allen, H E; Chen, P H ^[1]

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1. Univ. of Deleware, Newark, DE (United States)

Removal of toxic heavy metals from a soil matrix by the addition of ethylenediamine tetraacetic acid (EDTA) is an effective means of remediation. The liquid stream containing the metal and chelating agent is amenable to further treatment by electrolysis in which the metal can be separated from the chelating agent. This provides a separated metal than can be removed for reuse or treated for final disposal by conventional technologies and a reclaimed EDTA stream that can be used again for treatment of contaminated soil. Under the diffusion controlled conditions of polarography or voltammetry, the authors observed reduction of cadmium, copper and lead ions and their protonated EDTA complexes (MHY[sup [minus]]), but not of the non-protonated EDTA complexes (MY[sup 2[minus]]). Potentials applicable for metal deposition and, consequently, regeneration of the EDTA were established. To prevent electrochemical oxidation of EDTA during electrolysis they used a cell in which the anode and cathode compartments were separated by a cation exchange membrane. Tests with Pb-EDTA demonstrated that over 95 percent recovery of both EDTA and lead could be achieved by electrolysis. The lead that was deposited onto a copper electrode was a mixture of hydrolysis products and salts and the lead could be recovered by dissolution in acid. EDTA was equilibrated with soil before addition of lead. When electrolyzed, this sample released EDTA and deposited Pb to approximately the same extent as did the samples that had not been equilibrated with soil. 48 refs., 10 figs., 4 tabs.

• OSTI ID: 7063906
• Journal Information: Environmental Progress; (United States), Journal Name: Environmental Progress; (United States) Vol. 12:4; ISSN 0278-4491; ISSN ENVPDI
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320305 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Industrial Waste Management
54 ENVIRONMENTAL SCIENCES
540220* -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (1990-)
COMPLEXES
ELECTROLYSIS
ELEMENTS
LYSIS
MANAGEMENT
MATERIALS RECOVERY
METALS
PROCESSING
REMEDIAL ACTION
REMOVAL
SOILS
WASTE MANAGEMENT
WASTE PROCESSING