(715a) Controlled Oxidation of Trichloroethylene Using Polymer-Encapsulated Potassium Permanganate in the Presence of Hexavalent Chromium

Trichloroethylene (TCE) oxidation under different environmental conditions, media and in co-existence with hexavalent chromium (Cr⁺⁶) was evaluated. The specific objectives were focused on the oxidation of trichloroethylene in soil and aqueous media using both unmodified-KMnO₄ particles and poly methyl methacrylate (PMMA)-encapsulated KMnO₄ in the presence and absence of hexavalent chromium. Molar ratios (P-values) of KMnO₄ to TCE were used as a variable parameter in the TCE oxidation process. P-values of 2, 5 and 10 were investigated in aqueous media. Rate constant of 0.5M^-1s^-1 was obtained using unmodified KMnO₄ in aqueous system. The extent of oxidation did not change with TCE concentration. In soil system, TCE oxidation requires large amount of KMnO₄ to produce similar results as in aqueous system. Experiments indicated that except at high alkaline conditions, pH does not impact the extent of TCE oxidation. Also, the presence of Cr⁺⁶ did not inhibit TCE oxidation by KMnO₄. Using controlled release application_, the rate of TCE oxidation was reduced by PMMA-encapsulated KMnO₄. Comparative study indicated an expectedly slow rate of TCE degradation using modified-KMnO₄ but showed similar overall extent of oxidation for both modified and unmodified KMnO₄. The application of the encapsulated matrix yielded 88 ± 3% TCE oxidation and a simultaneous Cr⁺⁶ reduction by ferrous ion (Fe⁺²) of 81 ± 2.1% in the same system. Controlled release of oxidant provides a useful tool to control relative reaction rates in multicomponent systems with potential applications to hazardous waste treatment.