Enhanced magnetic separation and photocatalytic activity of nitrogen doped titania photocatalyst supported on strontium ferrite

An enhanced ferromagnetic property, visible light active TiO2 photocatalyst was successfully synthesized by supporting strontium ferrite (SrFe12O19) onto TiO2 doped with nitrogen (N) and compared with N-doped TiO2. The synthesized catalysts were further characterized with X-ray diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), BET surface area analysis, vibrating sample magnetometer (VSM), X-ray photon spectroscopy (XPS) and visible light spectroscopy analysis for their respective properties. The XRD and EDS revealed the structural and inorganic composition of N-TiO2 supported on SrFe12O19. The supported N-TiO2 exhibited a strong ferromagnetic property with tremendous stability against magnetic property losses. It also resulted in reduced band gap (2.8 eV) and better visible light absorption between 400 and 800 nm compared to N-doped TiO2. The photocatalytic activity was investigated with a recalcitrant phenolic compound namely 2,4-dichlorophenol (2,4-DCP) as a model pollutant under direct bright and diffuse sunlight exposure. A complete degradation of 2,4-DCP was achieved with an initial concentration of 50 mg/L for both photocatalysts in 180 min and 270 min respectively under bright sunlight. Similarly the diffuse sunlight study resulted in complete degradation for supported N-TiO2 and >85% degradation N-TiO2, respectively. Finally the supported photocatalyst was separated under permanent magnetic field with a mass recovery similar to 98% for further reuse. (C) 2011 Elsevier B.V. All rights reserved.