Optimizing redox cycling with α-Fe 2 O 3 /MoS 2 heterostructures for efficient degradation of antibiotics via peroxymonosulfate activation

Iron-based materials are widely utilized in sulfate radical advanced oxidation processes (SR-AOPs) due to their efficiency, cost-effectiveness, recyclability, and environmental sustainability. However, the continuous consumption of Fe(II) and the accumulation of excess Fe(III) often reduce catalytic efficiency and contribute to sludge formation. To overcome these limitations, we developed a novel alpha-Fe2O3/MoS2 nanocomposite catalyst, synthesized via a hydrothermal process. The synergistic interaction between alpha-Fe2O3 and MoS2 enhances the redox cycling of Fe and Mo ions. This redox cycling accelerates PMS activation, promoting the generation of reactive oxygen species (ROS) for tetracycline (TC) degradation. Compared with individual alpha-Fe2O3/PMS and MoS2/PMS systems, alpha-Fe2O3/MoS2/PMS system exhibits preferable catalytic performance, achieving 92% TC removal rate within 30 min. Mechanistic investigations using radical quenching and electron spin resonance (ESR) experiments confirmed the involvement of both radical and non-radical pathways in the degradation process. The enhanced catalytic activity is attributed to the efficient adsorption and decomposition of PMS, facilitated by the optimized composite structure. Furthermore, microbial toxicology tests displayed the reduced toxicity of the degradation byproducts. This study underscores the potential of alpha-Fe2O3/MoS2 nanocomposite as a highly efficient catalyst in the treatment of antibiotic wastewater.