Immobilization of 0D CuO/ZnFe2O4 nanoparticles onto 2D BiOBr nanoplates as dual S-scheme heterostructure for boosting photocatalytic oxidation of levofloxacin in wastewater: Magnetic reusability and mechanism insights

Recently, the fabrication of outstanding S-scheme heterojunction for antibiotic elimination was significantly developed but is still a big challenge. Herein, a dual-S-scheme system was designed and constructed by the integration of 0D CuO/ZnFe2O4 nanoparticles with 2D BiOBr nanoplates. The ternary CuO/ZnFe2O4/BiOBr (CO/ ZFO/BOB) heterojunction attained exceptional levofloxacin photo-efficiency of 91% in 90 min, with a substantial promotion of 5.61, 3.79, and 4.19 times exceeding those of BOB, ZFO, and CO, respectively. The coupling of CuO/ZnFe2O4 with BiOBr promoted the photons utilization and assisted the photo-carriers separation in a unique dual-S-scheme mode. Besides, the dual S-scheme route gained powerful photo-redox capacity, reflecting excel-lent photoactivity against the levofloxacin antibiotic under LED illumination. Furthermore, the CuO/ZnFe2O4/ BiOBr composite revealed excellent mineralization performance and obvious LEV degradation pathways. The degradation cycles reflected great stability and efficient reusability under an external magnetic field. The scavenging tests and electron spin resonance (ESR) characterizations demonstrated the key roles of & BULL;OH and & BULL;O2 in the levofloxacin elimination. The parameters influencing the photo-destruction activity and the proposed mechanism were also reported. This work underlines a novel approach for boosting the photoreaction by establishing a dual-S-scheme heterostructure for environmental detoxification.