On-site electro-generation of H2O2 combined with UV process: Multiple pharmaceutically active compounds degradation for drinking water systems

Atenolol (ATN), prednisone (PRED), and sulfamethoxazole (SMX) are widely used pharmaceuticals that persist in aquatic environments, posing risks to non-target organisms due to potential synergistic toxicity. This study investigates the degradation of these contaminants using electrochemical H2O2 generation (E-H2O2), alone and combined with UV-C irradiation, focusing on advancing water treatment technologies. The system employed an electrochemical reactor with a gas diffusion electrode (GDE) as the cathode and a cation exchange membrane to prevent H2O2 oxidation at the anode. A solid electrolyte was used for proton conduction to enhance practicality and reduce chemical inputs, and ionic adsorption capabilities were demonstrated, promoting electrostatic interactions with PhACs. At an optimized current density of 30 mA cm-2, contaminant degradation was evaluated across UV-C, E-H2O2, and the combined E-H2O2/UV-C system. The E-H2O2/UV-C process achieved the highest degradation efficiency within 15 min, breaking contaminants into simpler carboxylic acids and showing no phytotoxicity in Allium cepa bioassays. However, GDE characterization revealed morphological changes and catalyst loss after extended use, potentially impacting H2O2 generation stability and efficiency. These findings suggest that the E-H2O2/UV-C system holds potential for water treatment applications targeting multicontaminant degradation. Future studies should focus on developing more durable cathode materials to ensure sustained performance under prolonged operational conditions.