Enhanced tetracycline degradation with TiO₂/natural pyrite S-scheme photocatalyst

In this study, TiO₂ nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO₂ nanoparticles were decorated on natural pyrite (TiO₂/NP) and characterized using XRD, FTIR, and SEM–EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm²), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be ^·OH radicals in the TiO₂/NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO₂/NP system has high performance in photocatalytic TC removal under optimized experimental conditions.