Magnetic Bi2WO6 nanocomposites: Synthesis, magnetic response and their visible-light-driven photocatalytic performance for ciprofloxacin

Photocatalytic Bi2WO6 and magnetic Fe3O4 nanoparticles were synthesized with hydrothermal process, and then were bonded together with polyethylene glycol and oxidized to form Fe3O4/Bi2WO6 and gamma-Fe2O3/Bi2WO6 nanocomposites. The microstructure, component, magnetic response and photocatalytic degradation to ciprofloxacin (CIP) were studied with x-ray diffraction, N-2 adsorption-desorption isotherms, energy dispersive spectrometer, vibrating sample magnetometer and UV/Vis spectrophotometer. Bi2WO6 nanoparticles presented the highest CIP removal of about 98% in 120 min under visible light irradiation, which was higher than that of Fe3O4/Bi2WO6 (90%) and gamma-Fe2O3/Bi2WO6 (65%) nanocomposites. Both Bi2WO6-based nanocomposites could be easily separated by external magnetic field in 1 min. Fe3O4/Bi2WO6 nanocomposites showed the better synergistic effect of magnetic response and photocatalytic performance under visible light irradiation. Moreover, the photocatalytic mechanism for magnetic nanocomposites was deduced based on the energy band theory of semiconductor heterojunction contact.