Enhanced tetracycline degradation via photo-activated potassium persulfate catalyzed by cobalt ferrite/carbon nanocomposite.

Cobalt ferrite nanoparticles (CoFe₂O₄, CF) were anchored onto charcoal powder to create a magnetically separable CF@Charcoal nanocomposite. This heterogeneous catalyst was used to activate potassium persulfate (PPS) under ultraviolet (UV) irradiation (CF@Charcoal/PPS/UV) for the efficient degradation of tetracycline (TC). The synergistic system demonstrated remarkable performance, achieving ≥ 98% TC removal and 86% mineralization within 60 min under optimized conditions—significantly outperforming the catalyst-free UV/PPS process. The catalyst exhibited excellent stability and reusability over four consecutive cycles, retaining > 88% of its initial activity. When applied to real water matrices (tap and well water), the system maintained high efficiency, with only an 11–14% reduction in performance, highlighting its robustness. Crucially, phytotoxicity assays confirmed that the treated effluent was non-toxic to bean seeds. This work establishes the CF@Charcoal/PPS/UV system as a highly effective, sustainable, and practical strategy for antibiotic remediation.