Electrocatalytic destruction of the antibiotic tetracycline in aqueous medium by electrochemical advanced oxidation processes: Effect of electrode materials

Abstract

This paper presents the removal of the antibiotic tetracycline (TeC) from water using electrochemical advanced oxidation processes (EAOPs); namely electrochemical oxidation (EO) and electro-Fenton (EF). The effect of different cathode materials (carbon-felt and stainless steel) on the direct/indirect electro-oxidation of tetracycline, and that of different anode materials (Ti/RuO2–IrO2, Pt and BDD) on both processes was systematically investigated for the first time. The EO process was found to be more efficient in using the carbon-felt cathode than the stainless steel cathode. The EO and the EF processes using BDD anode demonstrated superior oxidation/mineralization power. Almost total mineralization (TOC removal up to 98%) of 100mgL−1 TeC solutions was achieved after 6h treatment either by EO and/or EF treatment with BDD anode. The oxidative degradation of TeC followed pseudo-first-order-reaction kinetics in using all tested electrodes and anode/cathode configurations. Apparent rate constants of different anode/cathode configurations increased in the following sequence: Ti/RuO2–IrO2/stainless steel<Ti/RuO2–IrO2/carbon-felt<BDD/carbon-felt (EO)<BDD/carbon-felt (EF). The electrical energy consumed per gram of TOC removal was calculated for different electrode configurations to assess the cost effectiveness of the EO and the EF processes to mineralize TeC in water.