Mineralization of chlorobenzene in aqueous medium by anodic oxidation and electro-Fenton processes using Pt or BDD anode and carbon felt cathode

Abstract

This study focuses on the in situ destruction of pesticide chlorobenzene (CB) by using two electrochemical advanced oxidation processes, namely anodic oxidation and electro-Fenton. Influence of several operating parameters such as applied current, catalyst concentration and supporting electrolytes was assessed to optimize oxidation and mineralization of CB. Kinetics study showed that CB is quickly oxidized by OH following a pseudo first-order reaction kinetics. The rate constant of oxidative degradation of CB by hydroxyl radicals was determined by competition kinetics method and found to be 4.35×109M−1s−1. The quasi complete mineralization (95% TOC removal) of 0.1mM CB aqueous solution was achieved at 4h treatment. Formation and evolution of aromatic and aliphatic (short-chain carboxylic acids) intermediates during treatment were monitored by HPLC analysis and a mineralization pathway was proposed. The results obtained highlight the great efficiency of electro-Fenton process in effective destruction of a very persistent pollutant such as CB that can be extrapolated to other toxic/persistent organic pollutants.