Recyclable Carbon Cloth-Supported Bi2WO6/BiOBr Heterojunction for Enhanced Visible-Light Degradation of Ciprofloxacin and Levofloxacin

To address the recalcitrant nature of fluoroquinolone antibiotics in aquatic environments and the poor recoverability and reusability of conventional powder-type photocatalysts, a synergistic design strategy that integrates heterojunction engineering with a conductive substrate is proposed in this study. A tightly coupled Bi2WO6/BiOBr heterojunction was in situ constructed on three-dimensional carbon cloth via a one-step hydrothermal method, simultaneously enhancing photocatalytic activity and structural recyclability. Comprehensive physicochemical characterizations demonstrate that the resulting composite exhibits broadened visible-light absorption and significantly improved interfacial charge-carrier separation. Under visible-light irradiation, the Bi2WO6/BiOBr-CC heterostructure shows markedly enhanced degradation performance toward two representative fluoroquinolone antibiotics, ciprofloxacin (CIP) and levofloxacin (LEV). Notably, the apparent pseudo-first-order rate constant for CIP degradation is 16.5 and 47.4 times higher than those of single-component Bi2WO6-CC and BiOBr-CC, respectively, while maintaining excellent cycling stability over repeated runs. Mechanistic investigations reveal that the intimate heterojunction interface, together with the conductive carbon cloth framework, effectively promotes charge separation and directional charge migration through an S-scheme pathway. Photogenerated holes and superoxide radicals are identified as the dominant reactive species responsible for pollutant degradation. Overall, this work provides an effective and practical approach for constructing high-performance, self-supported photocatalysts with enhanced activity, stability, and recyclability, offering valuable insights for the treatment of antibiotic-contaminated wastewater.