Heterogeneous electro-Fenton treatment of clofibric acid with an Fe₃O₄-loaded bifunctional carbon felt cathode via different anode types

Pharmaceutical pollutants like clofibric acid (CFA) pose significant threats to aquatic ecosystems and human health. In this study, a bifunctional cathode was synthesized by loading Fe ₃ O ₄ nanoparticles onto a carbon felt cathode using solvothermal method. The characterizations of CF@Fe ₃ O ₄ were performed using FESEM, CV and EIS. The developed CF@Fe ₃ O ₄ cathode was then evaluated in heterogeneous electro-Fenton (HEF) application in clofibric acid (CFA) oxidation at different current and pH values using Pt and BDD anodes. The CF@Fe ₃ O ₄ electrode accelerated electron transfer, minimizing mass transport limitations, enhancing CFA degradation. The CF@Fe ₃ O ₄ / Pt electrode pair exhibited 75% mineralization following 3 h of HEF treatment, whereas the BDD anode exhibited 78% mineralization at 50 mA. Both values outperformed the homogenous EF process with CF in terms of effectiveness. Radical scavenging experiments proved ^• OH as the dominant reactive species, with contributions from O ₂ ^•- and SO ₄ ^•- . Mineralization remained high (>85%) across pH 3–8, due to enhanced oxidation of intermediate products via BDD( ^• OH) and electron transfer mechanisms, while degradation slowed at higher currents. The CF@Fe ₃ O ₄ /BDD combination consistently outperformed Pt in terms of both degradation kinetics and energy efficiency. Here we show that even after 5 reuses, the CF@Fe ₃ O ₄ cathode/BDD anode pair can effectively remove persistent organic pollutants without pH limitation and with an environmentally friendly process without any significant performance loss.