Oxidation of volatile organic vapours in air by solid potassium permanganate

Abstract

Volatile organic compounds (VOCs) may frequently contaminate groundwater and pose threat to human health when migrating into the unsaturated soil zone and upward to the indoor air. The kinetic of chemical oxidation has been investigated widely for dissolved VOCs in the saturated zone. But, so far there have been few studies on the use of in situ chemical oxidation (ISCO) of vapour phase contaminants. In this study, batch experiments were carried out to evaluate the oxidation of trichloroethylene (TCE), ethanol, and toluene vapours by solid potassium permanganate. Results revealed that solid potassium permanganate is able to transform the vapour of these compounds into harmless oxidation products. The degradation rates for TCE and ethanol were higher than for toluene. The degradation process was modelled using a kinetic model, linear in the gas concentration of VOC [ML−3] and relative surface area of potassium permanganate grains (surface area of potassium permanganate divided by gas volume) [L−1]. The second-order reaction rate constants for TCE, ethanol, and toluene were found to be equal to 2.0 × 10−6 cm s−1, 1.7 × 10−7 cm s−1, and 7.0 × 10−8 cm s−1, respectively.