Degradation of Aqueous Phase Polychlorinated Biphenyls (PCB) Using Pulsed Corona Discharges

Abstract

AbstractThe efficacy of pulsed corona discharges, an effective technique for removal of small aromatic and volatile organic compounds in water, to degrade aqueous phase polychlorinated biphenyls (PCB) was tested. Experiments were conducted on the model PCB compound, 2,2′,4,4′- tetrachlorobiphenyl at its solubility limit (68 ppb) in water. The effects of various reactor configurations featuring liquid and combined liquid/gas discharges on the degradation rate and possible degradation mechanisms of the PCB congener were determined. The pulsed corona reactor led to nearly 70% degradation of the PCB congener within 60 min. Increased degradation rates due to the Fenton’s reactions were found upon the addition of ferrous salts in solution, and the degradation rate of the PCB was higher than those of phenol and nitrobenzene in the absence of ferrous salts. The two different reactor configurations tested, including direct discharge in water and simultaneous gas-liquid discharge, gave the same rate of PCB degradation in the Fenton’s case, thus raising the possibility that the PCB degradation mechanisms in both reactors are the same. The effect of the high voltage electrode material on the degradation of PCB was evaluated by performing experiments with electrodes made of either platinum or a nickel-chromium alloy.