Efficient Catalytic Ozone Degradation of Organic Pollutants by Anchoring MnFe ₂ O ₄ on Chitosan-Derived N-Doped Carbon-Modified MoS ₂

Organic pollutants present in wastewater pose severe threats to aquatic organisms and human health. In this study, a magnetic MFO/NCS@MoS₂ composite catalyst was successfully synthesized via a hydrothermal method and applied for catalytic ozonation of methylene blue (MB). The catalyst was systematically characterized using multiple techniques including XRD, FT-IR, SEM, TEM, and XPS. Results revealed that the incorporation of chitosan (CS) effectively expanded the interlayer spacing of MoS₂, which not only enhanced the structural stability but also promoted mass transfer and full exposure of active sites, thus promoting the generation of free radicals and nonfree radicals. As an electron donor, Mo⁴⁺ and unsaturated sulfur atoms on the surface of MoS₂ not only provided active centers for catalytic ozonation, but also promoted the valence cycling between Mn²⁺/Mn³⁺ and Fe²⁺/Fe³⁺. In this way, the active centers of Mo⁴⁺ and unsaturated sulfur from MoS₂ cooperated with the Mn/Fe bimetallic centers from MnFe₂O₄ to make the catalytic reaction continue. The 1.0MFO/NCS@MoS₂/O₃ system exhibited excellent catalytic activity and removed 99.13% of MB within 6 min. In addition, it possessed remarkable structural stability, strong anti-interference capability, and environmental compatibility. Radical trapping experiments verified that ¹O₂, O₂^•-, and ^•OH were involved in the degradation process. This study provides a new design strategy for developing efficient and recyclable ozonation catalysts.