Sustainable fabrication of cellulose beads supported CoFe₂O₄ and Ag-CoFe₂O₄ catalysts for enhanced tetracycline degradation via PMS activation

This study presents a heterogeneous advanced oxidation process (AOP) for antibiotic removal using fibrous cellulose beads (CB) as sustainable catalyst supports. The CB were fabricated from biomass through a green, mechanical approach that avoids cellulose dissolution, preserving their native fibrous structure. Two catalysts, CoFe₂O₄@CB and Ag-CoFe₂O₄@CB, were synthesized via co-precipitation and in situ silver doping. Structural analyses confirmed the spinel CoFe₂O₄ phase, successful Ag incorporation, uniform nanoparticle dispersion, and strong interfacial coupling involving mixed-valence Co/Fe species, Ag-related surface species, and multiple oxygen environments. Under identical optimal conditions identified by Response Surface Methodology (RSM) using a Box–Behnken Design (BBD) (0.40 g L⁻¹ catalyst, 0.50 g L⁻¹ peroxymonosulfate (PMS), 20 mg L⁻¹ tetracycline (TC), 50 min), Ag-CoFe₂O₄@CB achieved 96.18% TC degradation with a higher apparent pseudo-first-order rate constant (k = 0.0690 min⁻¹) than CoFe₂O₄@CB (93.35%, k = 0.0568 min⁻¹), corresponding to ∼43% lower residual TC after 50 min. The enhancement is attributed to Ag-mediated promotion of ROS generation and interfacial electron-transfer processes, while also imparting rapid antibacterial activity against Escherichia coli and Staphylococcus aureus. The fibrous CB architecture further improved catalyst stability, reusability, and mass transfer. The dissolution-free fibrous CB platform enables a scalable, bio-based, and multifunctional catalyst architecture for PMS-driven antibiotic abatement and microbial control in water treatment.