Photocatalytic degradation of methylene blue by magnetically separable BiVO_4 supported on Fe_3O_4 nanoparticles

摘要

Non-titania photocatalyst BiVO_4 was supported on SiO_2-coated Fe_3O_4 particles in order to solve the problems of photocatalyst recovery and reuse. The prepared photocatalyst BiVO_4/SiO_2/Fe_3O_4 (BiVO_4/SFN) was proved to be nano-sized (less than 10nm) by TEM characterization. The superpararaagnetism of BiVO_4/SFN was confirmed by a vibrating sample magnetometer (VSM). The photocatalyst can be easily separated experimentally by an external magnetic field in lab. XRD analysis proved the dominant existence of BiVO_4 crystals. The magnetic photocatalyst BiVO_4/SFN showed high photoactiviry for methylene blue (MB) decolorization under visible light above 400nm (72.1%) and a lower activity (21.8%) was observed under line spectra at 420nm. MB was almost not degraded by P25 titania at 420nm. The reusability experiment under visible light irradiation also demonstrated the potential application of magnetic photocatalyst in water and wastewater treatment.