BaTiO3/CdIn2S4 Heterojunction for Visible-light-driven Photocatalytic Degradation of Levofloxacin: Toxicity, Mechanisms and Pathways

The BaTiO 3 /CdIn 2 S 4 (2BTO/CIS) heterojunction photocatalysts were prepared via a self-assembly method for the degradation of levofloxacin (LEV) under visible light illumination. Compared to pure BTO and CIS, the 2BTO/CIS composite exhibited significantly enhanced photocatalytic activity, achieving LEV degradation efficiency of 86.1% within 60 minutes. The improved performance is attributed to the heterojunction structure, which broadened light absorption range, enhanced charge separation, and extended the carrier lifetime (6.07 × 10 -7 s), thereby promoting the generation of active species of ·O 2 - and h + . The charges transfer route at the interface of heterojunction driven by interfacial electric field was revealed based on radical trapping experiments, electron spin resonance (ESR) analysis, and density functional theory (DFT) calculations. According to the identified degradation intermediates, LEV degradation pathways were likely to involve depiperazinization and cleavage of the quinolone ring. Moreover, most of LEV degradation intermediates showed lower ecological toxicity. The composite also demonstrated good stability, maintaining 75.6% degradation efficiency after five cycles. This study provides reference for the potential application of perovskite-based heterojunctions in wastewater treatment.