A comprehensive study on the electrochemical advanced oxidation of antihypertensive captopril in different cells and aqueous matrices

Abstract

Anodic oxidation with electrogenerated H2O2 (AO-H2O2) of 130 mL of antihypertensive drug captopril was studied in sulfate medium, urban wastewater and synthetic urine using a BDD, Pt or IrO2 anode and an air-diffusion cathode. Oxidants were ¿OH formed during O2 evolution and active chlorine formed via anodic oxidation of Cl-. Drug removal decreased as: BDD > Pt > IrO2. The effect of pH and current density was examined. Further, 2.5 L of drug solutions in the same matrices with Fe2+ at pH 3.0 were treated by solar photoelectro-Fenton (SPEF) using a solar pre-pilot flow plant with a Pt/air-diffusion cell and a planar photoreactor. In sulfate medium, SPEF outperformed AO-H2O2 and electro-Fenton because of the efficient Fe3+ photoreduction. Low mineralization was achieved by the small generation of photoactive Fe(III)-carboxylate complexes. In urban wastewater, captopril was more rapidly removed due to active chlorine Two heterocyclic derivatives and four aliphatic acids were detected.