Study on the Performance and Mechanism of Fe7S8@Mn3O4 Activated Persulfate for Tetracycline Degradation

In recent years, antibiotics have been widely found in different types of water bodies, and these residues pose a serious threat to ecosystems and human health. Among the treatment methods for degrading antibiotics, advanced oxidation processes (AOPs) based on persulfate activation have received extensive attention and application due to their excellent degradation performance. In this study, the flower-like Fe 7 S 8 @Mn 3 O 4 catalyst material with agglomerated small particles attached to the surface was prepared by hydrothermal method to activate persulfate (PMS) to remove tetracycline. The results showed that the degradation rate of TC could reach 91% in 60 min when TC was 25 mg/L, catalyst dosage was 0.2 g/L and PMS was 0.3 g/L. The pH range was wide, and the degradation rate increased with the increase of temperature. HCO 3 − and H 2 PO 4− have a certain inhibitory effect on the catalytic reaction. Cl − , SO 4 2− and NO 3 − have little impact on the reaction system, and the catalytic material has strong applicability to the environment. The catalytic material has good reusability. Free radical quenching experiments showed that SO4· − , ·OH, 1 O 2 , O 2 · − all played a role. It was confirmed by EPR experiments that ·OH and SO4· − existed in the reaction system. The degradation pathways mainly include demethylation, deamidation, dehydroxylation, hydroxylation, ring-opening oxidation, etc.