Highly efficient degradation of antibiotic residues with reagent-free photoelectro-fenton via hollow fiber gas diffusion electrode

Abstract

Fenton advanced oxidation technology is a potential treatment option for emerging organic pollutants in wastewaters. The challenges in the effective activation and generation of H2O2 limit its practical applications. We designed a chemical reagent-free Photoelectric-Fenton (PEF) system. Using an electro-chemical oxygen reduction reaction (ORR) employing Cu hollow fiber gas diffusion electrodes (Cu-hf-GDE) H2O2 was generated and was subsequently converted to OH using Fe/CN thin film on batch wall reactors. This PEF system demonstrated efficient elimination of florfenicol at a concentration of 10 ppm. The study revealed that O2− were the key species for the electrical generation of H2O2, while OH were the dominant reactive oxygen species (ROSs) for florfenicol degradation. A mechanism for the degradation of florfenicol was proposed, and the ecotoxicity of florfenicol and its degradation intermediates was investigated. The reusability, stability, and application potential of the PEF system in real water bodies were also assessed. Overall, this work demonstrates an example of pollution control resulting from philosophy of green chemistry, which offers a promising pathway to reduce the chemical demand for advanced oxidation processes.