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

Abstract

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, N₂ 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.

Keywords:

• Support
• Diatomite
• TiO₂
• Dye
• Photocatalysis

Acknowledgments

The authors gratefully acknowledge the financial support by the National Technology R&D Program in the 12th five years plan of China (Grant Number 2011BAB03B07).