Oxidative Degradation of Nitrophenols in Aqueous Solution Induced by Plasma with Submersed Glow Discharge Electrolysis

Summary: The oxidative degradation of 4‐nitrophenol, 2,4‐dinitrophenol, and 2,4,6‐trinitrophenol in aqueous solution induced by plasma with submersed glow discharge has been investigated. The reaction intermediates were determined by high performance chromatography (HPLC). Various influencing factors such as the initial pH, the concentration of nitrophenols (NPs), and the catalytic action of Fe2+ were examined. The results indicate that the degradation pathways involve a slow opening of the aromatic ring followed by a rapid oxidation of the aliphatic compounds. The hydroxyl radicals are responsible for the primary attack of the NPs with formation of dihydroxynitrobenzenes. The attack of hydroxyl radical occurs at the ring positions activated by the presence of a phenolic OH group and a nitro group. The results suggested that the reaction obeyed a pseudo‐first order kinetic reaction and the proposed method is an efficient way for the nitrophenols degradation. Effect of pH on the degradation of 4‐nitrophenol. magnified image Effect of pH on the degradation of 4‐nitrophenol.