United States Department of Energy is currently pursuing technology that will lead to better and less expensive characterization, treatment, and disposal of mixed waste. Previous studies have shown that in situ remediation through redox reactions has potential to remediate metals and organic compounds when they exist individually environmental systems. This paper presents the feasibility of using oxidizing and reducing agents for the simultaneous remediation of metals and chlorinated hydrocarbons in environmental systems. Trichloroethylene (TCE) and hexavalent chromium (Cr(VI)) were selected as model contaminants. Ferrous iron, Fe(II) was used as a reducing agent while permanganate, (MnO4-), was used as an oxidizing agent. In the redox reaction, Cr(VI) is reduced to nonhazardous Cr(III), and Fe(II) is oxidized to ferric ion, Fe(III); while TCE is oxidized to chlorine and carbon dioxide and permanganate is reduced to manganese dioxide (MnO2). In the experimental analysis, the Cr(VI)-Fe(II) reaction yielded 100% and 98.6% reduction of Cr(VI) by excess Fe(II) in water and soil, respectively. The overall reaction was determined to be a second order reaction, first order with respect to both Cr(VI) and Fe(II). The TCE-KMnO4 reaction yielded 99.71% and 82.4% oxidation of TCE by excess MnO4-  in water and soil, respectively. The overall reaction was also determined to be a second order reaction, first order with respect to both TCE and MnO4- in both the aqueous and soil systems.

Kinetics of reductive reactions of hexavalent chromium in waste containing trichloroethylene

242nd National Meeting (2011)

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