As widely used antibiotic, sulfadiazine (SDZ) is an emerging contaminant.In this study, the chem. synthesized pyrite (FeS2) was fabricaed and employed for peroxymonosulfate (PMS) activation to degrade SDZ, the effects of PMS concentration, FeS2 dosage, solution pH were studied.Optimized 50 mg/L FeS2/184.4 mg/L PMS exhibited a remarkable SDZ (initial concentration of 10 mg/L) removal efficiency of 96.2 % within 5 min.The structural and morphol. characteristics of catalysts were systematically examinedMechanism investigation elucidated that FeS2/PMS process involved both non-radical and free radical pathways, 1O2, O·-2, HO· and SO·-4 collectively contributed to the removal of contaminants.This system maintained high removal efficiency for target pollutants across a broad pH range of 3-11 and under solution components including natural organic matter and inorganic anions.The possible degradation pathways and intermediate products were proposed.The toxicity assessment revealed that overall biol. toxicity of the intermediates was reduced.Addnl., this system achieved high degradation efficiency of coexisted quaternary ammonium compounds (QACs) and antibiotic (exceeded 96.0 %) within 5 min and about 6 logs CFU inactivation of QACs resistance bacteria within 60 min.These findings supplied a novel strategy to overcome the persistent challenge of antibiotic resistance.