Sulfonamide antibiotics are a common group of drugs that have the potential to induce the generation of resistance genes even at low concentrations. Herein, a novel Fe3Mo3C/Mo2C/Mo composite (Fe-Mo2C-1.0) was prepared by modifying the synthesis process of Fe-doped Mo2C and used to activate peroxymonosulfate (PMS) to degrade sulfamerazine (SMR). The optimal performance catalyst was obtained at Fe/Mo = 1.0 and a calcination temperature of 900 ℃. Fe-Mo2C-1.0 achieved 98.8 % SMR removal in 20 min, which was 4.5 and 44.3 times higher than that of Fe-Mo2C-0.5/PMS and Mo2C/PMS systems, respectively. In Fe-Mo2C-1.0, multiple low-valent forms of the element Mo, including Mo, Mo(II) and Mo(IV), which are highly reductive, participated in and contributed to the regeneration of Fe(II). The proportion of Fe(II) on the surface of Fe-Mo2C-1.0 before and after the reaction was maintained at a stable level. In addition, the high Fe content and sp2 hybridized carbon in Fe-Mo2C-1.0 promoted the role of mediated electron transfer during catalysis process. Electrochemical characterization indicated that Fe-Mo2C-1.0 had better redox properties, smaller electron transfer resistance and a faster corrosion rate than Fe-Mo2C-0.5 and Mo2C. Other SMR oxidation mechanisms included SO4∙-, O2∙- and 1O2, with 1O2 contributing the most. Finally, three possible degradation pathways of SMR were proposed. This work provided thoughts on the synthesis of Fe/Mo bimetallic carbide catalysts as well as reference for the removal of SMR by PMS activation.
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