Electrochemical degradation of chloramphenicol with a novel Al doped PbO2 electrode: Performance, kinetics and degradation mechanism

This study presents an electrochemical method for the degradation of chloramphenicol (CAP) in aqueous solution with a novel Al doped PbO2 electrode. The Al-doped PbO2 electrode showed high electrochemical activity, oxygen evolution potential, radical utilization rate, reusability and safety. The influence factors on CAP degradation with the Al-doped PbO2 electrode were investigated in detail, and under the optimal conditions the removal rates of CAP and TOC reached 87.30% and 52.06% in acid conditions after 2.5 h electrolysis with a 0.2 mol dm(-3) Na2SO4 at a current density of 30 mA cm(-2), respectively. The electrochemical degradation of CAP at Al-doped PbO2 electrode electrode followed pseudo-first-order kinetics. The degradation mechanism was proposed by cyclic voltammograms tests and it was deduced that hydroxyl radicals generated in the electrochemical process played a key role in oxidizing CAP. Finally, based on the reaction products identified, a possible degradation pathway including radical reaction, ring open and mineralization was proposed. (C) 2015 Elsevier Ltd. All rights reserved.