Peroxi‐coagulation of Aniline in Acidic Medium Using an Oxygen Diffusion Cathode

Abstract

A novel electrochemical method for wastewater treatment, called peroxi‐coagulation, is presented in this paper. Degradation of aniline in acidic solution of pH ∼ 3 has been studied using this method. Electrolyses were performed in an undivided cell with an Fe anode and a carbon‐polytetrafluoroethylene ‐fed cathode which continuously electrogenerates . The anode dissolves yielding and . This last ion gives a precipitate of hydrated Fe(III) oxide. Aniline and its intermediates are oxidized mainly by reaction with OH•, which is produced from Fenton's reaction between electrogenerated and . Competitive coagulation of oxidation products with the hydrated Fe(III) oxide precipitate also occurs. These processes allow a fast and almost complete total organic carbon removal for aniline solutions in short‐time electrolyses. The method has higher decontamination power than other electrochemical treatments tested, such as electrocoagulation with a graphite cathode, and electro‐Fenton and photoelectro‐Fenton with a Pt anode. Benzoquinone, nitrobenzene, , and were detected in electrolyzed solutions. Precipitates contain coagulated organics with a major proportion of nitrogen‐containing compounds. A pathway for aniline peroxi‐coagulation involving these species is proposed.