Scalable synthesis of AgX (Cl, Br, I, PO4) nanophotocatalysts for efficient visible-light degradation of persistent antibiotics from aqueous environments

The environmental persistence of Nitrofuran antibiotics, particularly Nitrofurazone (C₆H₆N₄O₄) and Furagin (C₁₀H₈N₄O₅), poses a serious threat to aquatic ecosystems due to their bioactivity, chemical stability, and resistance to conventional treatment. In this study, silver-based photocatalysts (AgCl, AgBr, AgI, and Ag₃PO₄) were synthesized via a scalable mechanochemical route and systematically evaluated for the visible-light-driven degradation of Nitrofurazone (NFZ) and Furagin (FUR). All catalysts demonstrated activity under visible light, with Ag₃PO₄ and AgCl achieving the highest degradation efficiencies: up to ∼95 % removal of NFZ (rate constant k = 0.03468 min⁻¹) and ∼ 99 % removal of FUR (k = 0.05891 min⁻¹) within 90 min. In contrast, AgBr exhibited limited performance (e.g., 70 % NFZ and 40 % FUR remaining after 90 min). The enhanced photocatalytic activities of Ag₃PO₄ and AgCl were attributed to efficient visible-light absorption, favorable band structures, and dominant reactive oxygen species (h⁺ and ^•OH). Recyclability tests confirmed stability over five cycles with >70 % activity retention. This work demonstrates a green, solvent free synthesis of silver-based nanophotocatalysts and their quantitative performance metrics in degrading recalcitrant pharmaceutical pollutants, offering a promising approach for solar-driven water purification.