In order to enhance the effectiveness of pollutant removal by photocatalysis under visible light, a multifunctional photocatalyst was prepared by grafting polydopamine (PDA) with the core-shell nanocomposite Fe 3 O 4 @SiO 2 @TiO 2 (FST). The structural, morphological, and magnetic responses of FST@PDA were characterized by X-ray diffraction pattern, Fourier transform infrared spectroscopy, transmission electron microscopy, etc. FST@PDA showed a high degradation rate of rhodamine B, reaching 98.7 % and 95.7 % after 150 min of ultraviolet and visible light radiation, respectively. In addition, the prepared FST@PDA had good safety and high recyclability due to the strong covalent bonds between FST and PDA.

A polypyrrole-modified Fe3O4/SiO2/TiO2 composite material was successfully synthesized on the FST surface by in situ polymerization of pyrrole. Structural, morphological and magnetic response of Fe3O4/SiO2/TiO2/PPy(FST/PPy) were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction pattern, Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy, etc. Through SEM images, the crystal sizes of the prepared FST/PPy nanoparticles were determined to be about 110 nm. The catalytic activity of FST/PPy was evaluated by the degree of decomposition of rhodamine B under ultraviolet and visible light, respectively. FST/PPy had the photocatalytic activity under the action of the light: the degradation rate of rhodamine B reached 92.8% and 63.5% after 3 h of UV and Vis light irradiation, respectively. Especially, compared with FST, the degradation rate has shown obvious improvement under the action of Vis light. Furthermore, FST/PPy photocatalyst could be easily recycled using a magnet.

No abstract