A low-cost photoactive composite quartz sand/TiO2

Abstract

The photoactive quartz sand/TiO2 composites were prepared by thermal hydrolysis of the suspension obtained by addition of quartz sand to a titanyl sulfate solution. The required amount of TiO2 in the prepared composites (i.e. 9, 22 and 45 wt.%, respectively) was achieved using a variable titanyl sulfate/quartz ratio. As reference materials, pure TiO2 was prepared using the thermal hydrolysis of the titanyl sulfate solution under the same condition as used during the preparation of composite quartz/TiO2. The composite samples, dried at 105 °C and calcined at temperatures of 500–900 °C, were investigated using X-ray fluorescence spectroscopy, X-ray powder diffraction analysis, transmission electron microscopy, and Fourier transform infrared spectroscopy. Structural ordering of TiO2 particles on the quartz surface was studied using atomistic simulations in a Material Studio modeling environment. Photodegradation activity of the composites was evaluated by the discoloration of Acid Orange 7 aqueous solution. The composite containing 22 wt.% of TiO2 and calcined at 800 °C exhibits the highest photoactivity. Higher and lower amounts of TiO2 led to worse results. The quartz/TiO2 composite is a promising material able to replace pure TiO2 in a wide range of building materials.