Preparation and characterization of a magnetically separated photocatalyst and its catalytic properties

A kind of loaded photocatalyst of TiO2/gamma-Fe2O3 (TF) that can photodegrade organic pollutants in the dispersion system effectively and can be recycled easily by a magnetic field is reported in this paper. The structural features of TF catalyst sintered at different temperatures (in the range 200-900 degreesC) have been investigated by X-ray diffraction, atomic force microscope and transmission electron microscope studies. Phase composition and crystallinity change with the increasing sintering temperature of the specimens. The TF photocatalyst is composed of two parts: (1) TiO2 shell used for photocatalysis; (2) gamma-Fe2O3 core for separation by the magnetic field. Due to the strong light absorption by gamma-Fe2O3, when the amount of the loaded TiO2 content was under 30% in the catalyst, the photocatalytic activity of TF was significantly lower than that of the pure TiO2. On the other hand, the photocatalytic activity of TF reduced to a large extent at high sintering temperature (900degreesC) owing to the presence of inactive (Fe2TiO5) pseudobrokite phase. The sample sintered at 500 degreesC showed the highest activity for the degradation of aqueous solution of acridine dye. (C) 2002 Elsevier Science B.V. All rights reserved.