Enhanced sulfadiazine degradation through synergistic visible light assisted peroxymonosulfate activation using a...

In this study, a novel magnetic Fe₃O₄-ZnIn₂S₄ heterojunction catalyst was synthesized via a solvothermal method and evaluated for sulfadiazine (SDZ) degradation under visible-light-assisted peroxymonosulfate (PMS) activation. The Fe₃O₄-ZnIn₂S₄ catalyst was synthesized through a solvothermal method and characterized using morphological, optical, and magnetic techniques. Under optimized conditions (pH = 3.0, 0.4 g/L catalyst dosage, 2 mM PMS, and 75 W/cm² visible light), the system achieved almost complete SDZ degradation (Re = 97.54%, with a rate constant (K_obs) of 5.640E-02 min⁻¹) within 60 min, with a suitable mineralization efficiency (68.06% TOC removal and 77.44% COD removal). Scavenger experiments and EPR confirmed that both SO₄•⁻ and •OH radicals were dominant reactive species for the oxidative process. The catalyst demonstrated robust stability and recyclability over five cycles, with negligible leaching of metal ions. The degradation pathway was elucidated via HPLC/MS, indicating sulfonamide bond cleavage, aromatic ring hydroxylation, and progressive oxidation into low molecular weight acids and inorganic species. The findings highlight the Vis-Fe₃O₄-ZnIn₂S₄/PMS system as a promising candidate for sustainable and efficient antibiotic removal in water treatment applications.