Bifunctional catalysts based on carbon-coated manganese microspheres applied in the heterogeneous electro-fenton process for tetracycline degradation

Antibiotic contamination in water is a major threat to public health and ecosystems, driven by the spread of resistant bacteria and challenges in treating diseases. Tetracycline (TC), a widely used and persistent antibiotic, has prompted the development of advanced oxidation processes like electro-Fenton for its removal. In this study, carbon-coated manganese microspheres were synthesized as bifunctional electro-Fenton catalysts capable of carrying out oxygen reduction reaction (ORR) and TC degradation in the same electrochemical process. The C90Mn10 formulation, with a high carbon xerogel content, exhibited excellent ORR activity and achieved 90 % TC degradation after 300 min of treatment. This performance was attributed to the synergistic activity of Mn 2 + /Mn 3+ species and the carbon xerogel in generating hydroxyl radicals via direct and indirect pathways. The catalyst demonstrated stable performance over multiple cycles, maintaining structural integrity and resisting leaching due to the carbon coating. These findings underscore the potential of carbon-coated manganese catalysts as efficient and scalable solutions for removing pharmaceutical contaminants like TC from wastewater. • Carbon xerogel-coated manganese microspheres were efficiently synthesized. • Higher carbon xerogel content increased surface area, mesoporosity, and Mn 2+ sites. • C90Mn10 catalyst showed bifunctional activity in the electro-Fenton process. • Dual •OH generation via Mn 2+ /Mn 3+ sites and carbon xerogel was observed. • Almost total TC degradation (90 %) was achieved after 300 min of reaction