SURFACTANT-ENHANCED OXIDATION OF TRICHLOROETHYLENE BY PERMANGANATE – PROOF OF CONCEPT

Oxidative dechlorination of chlorinated solvents by permanganate is an emerging technology for remediation of groundwater contaminated with dissolved chlorinated contaminants. In this study, the enhancement of trichloroethylene (TCE) degradation by permanganate in aqueous solution in the presence of surfactant was evaluated through a continuous stir batch reactor system with the presence of permanganate as the limiting reagent and free phase TCE. The TCE degradation was determined by continuous monitoring the amount of chloride produced, which was then reverted to the rate of permanganate consumption. It was found that the chloride production, an indication of TCE degradation, followed a pseudo-first-order reaction kinetics with respect to KMnO₄ in the presence of free phase TCE. When no surfactants were present, the observed pseudo-first-order rate constant (k_obs ) was 0.08-0.19 min^-1 and the half-life (t_1/2 ) was 4-9 min for MnO₄ ^-. When the surfactant concentration was less then its critical micelle concentration (CMC), the kobs values increased to 0.42-0.46 min^-1 and the t_1/2 reduced to 1.5-1.7 min for MnO₄ ^-. As the surfactant concentration was greater than the CMC, the k_obs values increased to 0.56-0.58 min^-1 and the t_1/2 reduced to 1.2-1.3 min. The results indicate that it is feasible to achieve a synchronized ~{!0~}pump-while-treat~{!1~} for soils and groundwater contaminated with free phase DNAPLs when surfactant-enhanced pump-and-treat is combined with permanganate oxidation.