The removal of clofibric acid (CA) in aqueous solution by ferrous ion activated peroxymonosulfate (PMS) oxidation in an electrochemical reactor (EC/Fe3+/PMS) was performed in this study. The process involved the use of a dimensionally stable anode (DSA) and a stainless steel cathode. Ferrous ion was produced from cathodic reduction of externally applied ferric ion and activated PMS for the generation of sulfate radicals (SO4 center dot-). Various parameters were investigated to optimize the process, including PMS concentration, Fe3+ concentration and current density. The results indicated that the removal efficiency increased with the increase of PMS concentration, Fe3+ concentration and current density. The scavenging effect was examined by using ethanol (EtOH) and tert-butyl alcohol (t-BuOH) to identify the reactive radicals in EC/Fe3+/PMS process. The TOC removal efficiency was 30.8% in 60 min reaction, and it reached 64.7% when the reaction time was extended to 180 min. The GC-MS analysis was employed to identify the intermediate products and a plausible degradation pathway was proposed. (C) 2014 Elsevier B.V. All rights reserved.