Dual Z-scheme-driven sonophotocatalytic degradation of norfloxacin via PMS activation using BiVO₄@LaCoO₃@g-C₃N₅: Mechanisms, pathways, and environmental applications

The contamination of aquatic environments by persistent pharmaceutical pollutants poses significant challenges, necessitating the development of advanced catalytic systems for their effective removal. This study presents a novel BiVO₄-LaCoO₃@g-C₃N₅ (BVLCO@gCN) composite, designed for sonophotocatalytic degradation of norfloxacin (NOR) via peroxymonosulfate activation under ultrasonic-visible conditions. The 25BVLCO@75gCN composite exhibited outstanding catalytic performance, achieving 97.9% NOR degradation after 30 min of adsorption followed by 15 min of degradation, with a pseudo-first-order rate constant of 0.1995 min⁻¹. Comprehensive material characterization using Brunauer-Emmett-Teller surface area, X-ray photoelectron spectroscopy, and X-ray diffraction analysis revealed an enhanced surface area, efficient charge transfer properties, and strong interfacial interactions between BiVO₄@LaCoO₃ (BVLCO) and g-C₃N₅. Mechanistic investigations through electron spin resonance spectroscopy and radical scavenger experiments confirmed that singlet oxygen (¹O₂) and hydroxyl radicals (^•OH) were the primary reactive species driving NOR degradation. Additionally, the BVLCO@gCN composite demonstrated excellent stability and reusability, retaining over 95% efficiency after five regeneration cycles. These findings highlight the potential of BVLCO@gCN as a multifunctional catalyst for the effective removal of pharmaceutical contaminants, contributing to sustainable water management solutions.