Integrated persulfate/ozonation process using Fe3O4/AC catalyst for antibiotic degradation: optimization and kinetic insights

Antibiotics are considered emerging contaminants due to their persistence and potential ecological risks. Among them, cefixime is frequently detected in pharmaceutical effluents and requires effective removal strategies. This study aimed to optimize catalytic ozonation for cefixime degradation using persulfate activated by magnetic activated carbon (Fe3O4/AC or MAC). The effects of pH (5–11), contact time (5–60 min), catalyst dose (0–2.5 g/L), initial cefixime concentration (10–200 mg/L), and persulfate concentration (0–70 mM) were evaluated. A central composite design (CCD) under response surface methodology (RSM) was applied to model and optimize the process. Model performance was assessed by statistical indicators. The quadratic model showed good predictive ability (R2 = 0.90). Reaction time and pH were the most significant variables influencing cefixime degradation. Under optimized conditions (pH 8, cefixime 57.5 mg/L, MAC 1.5 g/L, persulfate 1.75 mM, and 46.25 min contact time), 97% removal efficiency was achieved. The findings indicate that catalytic ozonation activated with persulfate and MAC is an effective and statistically validated process for cefixime removal from aqueous solutions. These results support its potential applicability for pharmaceutical wastewater treatment.