Treatment of aqueous solutions of oxytetracycline by different electrochemical approaches: anodic oxidation, pressurized electro-Fenton and oxidation by electrogenerated active chlorine

The tetracycline group (TCs) includes the most common antibiotics for treatment of both human and animal infections. TCs are resistant to biological degradation; hence, conventional wastewater treatments are unable to remove these contaminants. Here, the utilization of different electrochemical processes, such as electro-Fenton (EF), direct anodic oxidation (AO) and indirect oxidation by electrogenerated active chlorine (EAC), for the treatment of aqueous solutions of oxytetracycline (OTC), which is one of the TCs, was studied. The effect of various operating conditions was evaluated to optimize the selected processes. EAC gave the fastest abatement of OTC, but the lowest removal of TOC and formation of chlorate. However, the utilization of carbon felt cathodes allowed the formation of chlorate to be reduced. AO gave the highest TOC removals, but it required the use of an expensive anode, as BDD, and high cell potentials. EF performed with pressurized-air (5–10 bar) presented intermediate removals of OTC and TOC with respect to AO and EAC and consumed the least energy.