Enhanced photocatalytic degradation of levofloxacin over heterostructured C(3)N(4)/Nb(2)O(5) system under visible light

The growing usage of antibiotics and their subsequent release in water bodies have become a serious environmental concern. In this study, heterostructured photocatalysts C(3)N(4)/Nb(2)O(5) have been synthesized using a simple hydrothermal method and applied to facilitate the degradation of the widely used antibiotic levofloxacin. The structural, morphological, and optical properties of the photocatalysts were characterized using XRD, SEM, TEM, UV–Vis and PL to establish the structure-property relationship. The type-II heterojunctions C(3)N(4)/Nb(2)O(5) show remarkable activity under visible light irradiation, where Nb(2)O(5) facilitates preferential adsorption of levofloxacin at the catalyst surface while C(3)N(4) extends visible light absorption. This synergy resulted in superior catalytic performance (91%) in the optimized system, exceeding that of individual materials (Nb(2)O(5) 30% and C(3)N(4) 56%). The effect of catalyst dosage, pH, oxygen and point of zero is also investigated. The process is mainly photo-driven, and the trapping experiments reveal superoxide radicals as key species responsible for the degradation. Additionally, the adsorption behaviour, reformation of the degraded pollutant and reusability factors are evaluated to assess the practical feasibility of the photocatalytic system.