The effect of redox potential on the electrokinetic remediation of mercury contaminated soils

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:416880

Cox, C D; Shoesmith, M A; Ghosh, M M ^[1]

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1. Univ. of Tennessee, Knoxville, TN (United States)

An electrokinetic process for remediation of mercury contaminated soils using an iodine-iodide lixiviant was developed. In this process, reduced forms of insoluble mercury are oxidized by iodine. Iodide then reacts with mercury to form the highly soluble HgI{sub 4}{sup 2-} complex, which in turn migrates toward the anode via electromigration. The objective was to determine the thermodynamic conditions under which mercury could be solubilized and transported from the soil. At the end of the electrokinetic treatment process, pH, pE, iodine, iodide, and soluble and total mercury were measured along the length of the soil. The process was tested on a soil contaminated with HgS (cinnabar) in the laboratory and a contaminated soil obtained from a hazardous waste site. Up to 99% overall removal of mercury could be achieved from the laboratory contaminated soil. Up to 84% of mercury was removed from some sections of the field contaminated soil, but overall removal was only 6%. The presence of iodine in the soil pore water was found to be the most important factor in solubilization of mercury. Residual levels of soluble Hg remaining in soil after treatment were greater than allowed by current regulations and far in excess of the solubility of Hg compounds present in the untreated soil.

• OSTI ID: 416880
• Report Number(s): CONF-951023--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ANODES
ELECTRODYNAMICS
IODINE
MERCURY
MERCURY IODIDES
OXIDATION
PH VALUE
REDOX POTENTIAL
REMEDIAL ACTION
SOILS
SOLUBILITY