Efficient Activation of Peroxymonosulfate by CoFe₂O₄/MoS₂/N-MWCNT for Rhodamine B Degradation

A composite catalyst, CoFe₂O₄/MoS₂/N-MWCNT (CF/M/NCNT), was synthesized and used to activate peroxymonosulfate (PMS) to degrade rhodamine B (RhB). The degradation process involved the interaction of free radicals and nonfree radicals, and 99.44% of RhB was removed in 7 min. This excellent degradation performance was attributed to the redox cycling between Co, Fe, and Mo in CF/M/NCNT, which was accelerated by the unsaturated S. N-doped MWCNTs introduced many active sites, while improving the stability and the electron transport capacity of the composite. The experimental and characterization results showed that CF/M/NCNT exhibited strong resistance to acids and alkali, anti-interference capacity, stability and reusability, good degradation ability for different pollutants, and excellent electron transport ability. The main reaction sites of RhB were determined using density functional theory (DFT). The degradation process of RhB was mainly divided into three phases, namely, de-ethylation, chromophore breakage, and ring opening. The toxicity of degradation products was determined with Ecosar software, and the leaching concentrations of Co, Fe, and Mo were monitored during recycling, which confirmed the ecological security of the system. This study provided insight into the synthesis of eco-friendly and efficient multiphase PMS activators.