Oxidative degradation of phenol in aqueous electrolyte induced by plasma from a direct glow discharge

The liquid-phase oxidation of phenol induced by plasma that was generated from direct glow discharges at the tip of a platinum anode in aqueous electrolyte was investigated. Various influencing factors such as the initial pH, the concentration of reactants and the catalytic action of Fe 2+ were examined. The results suggest that the reaction is a pseudo-first-order kinetic reaction; the initial pH significantly affects the degradation velocity and ferrous ions displayed a remarkable catalytic effect on the oxidation. The major oxidation intermediates were identified with high-performance liquid chromatograph and ion chromatograph analysis. It was found that the degradation proceeded differently in the presence and absence of catalysts and consequently two degradation pathways were proposed.