A review of cobalt-based heterogeneous catalysts for peroxomonosulfate activation and antibiotics degradation: Catalyst synthesis, characterizations, regulation, and mechanism

Abstract

Antibiotics are extensively utilized in both human and veterinary medicine, leading to the accumulation of antibiotic residues in natural water. Cobalt-based heterogeneous catalysts (Co-HCs) for peroxomonosulfate (PMS) activation have emerged as an effective solution for antibiotic degradation. This review comprehensively examines the synthesis methods and characterizations of Co-HCs, elucidating the active sites of these catalysts and introducing the activation pathways of the Co-HCs/PMS system. Various strategies to enhance the activation efficiency are discussed, alongside a summary of the applications of Co-HCs/PMS in antibiotic degradation. The activation mechanisms encompass radical pathways (SO4-∙ and ∙OH) and non-radical pathways (1O2, electron transfer, high-valent cobalt oxides, and surface-bound sulfate radicals). Key design strategies of catalysts include size reduction, Co-loading, non-metallic doping, metallic doping, multi-reaction centers, and morphology regulation. The Co-HCs/PMS system achieves antibiotic degradation efficiencies of 90–100%. Despite significant advancements, challenges persist in the rational design and facile synthesis of catalysts, a deeper understanding of catalytic mechanisms, process enhancement, and larger-scale applications in wastewater treatment. This review provides valuable insights and guidance for the development of sulfate radical-based advanced oxidation processes (SR-AOPs) for the treatment of antibiotic-contaminated wastewater using Co-HCs.