Efficient Activation of Peroxymonosulfate for Degradation of Rhodamine B by Anchoring CoFe2O4 on MoS2 Nanoflower-Modified Biochar.

In this study, CoFe2O4 anchored by MoS2 modified biochar (CoFe2O4@MoS2-BC) was synthesized using a hydrothermal approach and utilized to activate peroxymonosulfate (PMS) to degrade rhodamine B (RhB). The effects of pH value, catalyst and PMS dosage, RhB concentration, and coexisting compounds were systematically investigated. Within 7 min, CoFe2O4@MoS2-BC achieved a removal rate of 99.63% for 100 mg·L-1 RhB. The outstanding stability and environmental compatibility of CoFe2O4@MoS2-BC was verified by cycling and metal ion leaching experiments. The contribution of 1O2, SO4•-, •OH, and •O2- in the degradation procedure was revealed by quenching experiments, among which 1O2 was the predominant active species. Electrochemical characterization indicated that CoFe2O4@MoS2-BC exhibited enhanced current density, redox activity, and superior electron transfer capability. Comprehensive characterization analysis and experimental data revealed that the high efficiency of CoFe2O4@MoS2-BC was attributed to Co2+/Co3+, Fe2+/Fe3+, and Mo4+/Mo6+ redox cycling on the CoFe2O4@MoS2-BC surface. The cycles of Co2+/Co3+ and Fe2+/Fe3+ were enhanced by Mo, while unsaturated S increased the reactivity of Mo, thereby accelerating the redox of metal ions; oxygen vacancies (Ov) enhance the mobility of surrounding oxygen ions mobility and promoted the conversion from lattice oxygen (Olat) to reactive oxygen species (O*), thereby activating PMS effectively. This research is expected to provide innovative insights that will inform the design and development of excellent activity and stability of heterogeneous metal-based catalysts.