A comparative study of different diatomite-supported TiO2 composites and their photocatalytic performance for dye degradation

Three kinds of diatomites as catalyst carriers were adopted to prepare supported TiO2 catalysts by a typical hydrolysis-deposition method. The prepared composites were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, N-2 adsorption-desorption, scanning electron microscopy transmission electron microscopy, UV-vis diffuser reflectance, and chemical oxygen demand. The photocatalytic properties of composites were determined using rhodamine B, methyl orange, and methylene blue as target pollutants under UV light irradiation. A comparative study on the photocatalytic properties of composite catalysts was carried out. It is indicated that the catalytic performance of TiO2/diatomite is significantly influenced by the physicochemical properties of diatomite supports. Compared with pure TiO2, the TiO2/diatomite composites exhibited smaller crystalline size of TiO2 and better dispersibility, which induced higher specific surface area and better photo-degradation efficiency. The highest activity of the photocatalyst should be attributed to the acid-activated support, which provided more active sites for the degradation reaction. Besides, the durabilities of catalysts were also investigated. The experimental results indicated that the prepared composite is a promising material for the wastewater treatment for its good photocatalytic property and reusability.