Electrokinetic remediation of mercury-contaminated soils using iodine/iodide lixiviant
- Univ. of Tennessee, Knoxville, TN (United States)
In-situ remediation of mercury-contaminated soils, by electrokinetic or other means, is difficult because of the low solubility of mercury and its compounds. In this research, enhanced electrokinetic remediation of HgS-contaminated soils using I{sub 2}/I{sup -} lixiviant was investigated using bench-scale electrokinetic cells. The thermodynamic conditions under which the lixiviant could be effective were determined by constructing a pE-pH diagram for the Hg-S-I system. Introduced near the cathode, the lixiviant migrated through the soil to the anode by electromigration. Mercury, released by the oxidation of HgS compounds by I{sub 2}, was complexed as HgI{sub 4}{sup 2-}. The negative complex continued to electromigrate toward the anode. Up to 99% of the Hg present in laboratory-contaminated soils could be removed. Electrokinetic treatment of a field-contaminated soil, containing more organic matter than the laboratory-contaminated soil, occurred much slower. The critical issues in determining the efficacy of the process are the oxidation of reduced Hg by I{sub 2} and I{sub 3}{sup -} and the transport of the resultant HgI{sub 4}{sup 2-} complex. 17 refs., 7 figs., 2 tabs.
- DOE Contract Number:
- FC05-92OR22056
- OSTI ID:
- 263217
- Journal Information:
- Environmental Science and Technology, Vol. 30, Issue 6; Other Information: PBD: Jun 1996
- Country of Publication:
- United States
- Language:
- English
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