Preparations and photocatalytic degradation of methyl orange in water on magnetically separable Bi12TiO20 supported on nickel ferrite

Abstract: A magnetically separable photocatalyst Bi₁₂TiO₂₀/SiO₂/NiFe₂O₄ (BSN) with a typical ferromagnetic hysteresis was prepared by a simple process: the magnetic 200wt% SiO₂/NiFe₂O₄ (SN) dispersion prepared by a liquid catalytic phase transformation method and the visible-light-active photocatalyst Bi₁₂TiO₂₀ prepared by a simple coprecipitation processing were mixed, sonificated, dried, and calcined at 550°C. The prepared photocatalyst showed high photocatalytic activity for the degradation of methyl orange in water under UV irradiation and visible-light irradiation (λ>400nm), and it was easy to be separated from a slurry-type photoreactor under the application of an external magnetic field, being one of promising photocatalysts for wastewater treatment. Transmission electron microscope (TEM) and X-ray diffractometer (XRD) were used to characterize the structure of the photocatalyst, indicating that the magnetic SN particles adhered to the surface of the Bi₁₂TiO₂₀ congeries. SiO₂ layer round the surface of NiFe₂O₄ nanoparticles prevented effectively the injection of charges from TiO₂ particles to NiFe₂O₄, which gave rise to the increase in photocatalytic activity. [Copyright &y& Elsevier]