Photocatalytic activity of nano-tio2 on glass in building envelope

Abstract

Titanium dioxide is manufactured by processing naturally occurring titanium containing rutile (TiO2) or ilmenite (FeTiO3) minerals. Sri Lanka has vast deposits of ilmenite which is the major raw material in TiO2 production. However, Sri Lanka currently does not produce any type of value added TiO2 pigments. With the growth of nanotechnology, nano-TiO2 is now produced worldwide using different methods varying the particle size from 1 nm to 100 nm. Nano-TiO2 has the tightly controlled particle size that increases both the refractive index and light scattering properties as a result of the uniform particle size distribution and additional surface area. Nano-TiO2 is particularly interesting in UV resistant surface coatings where it can act as a UV reflector. Because of the higher photocatalytic activity nano-TiO2 can be used for anti-fogging coatings where nano-TiO2 incorporated into outdoor building materials can substantially reduce concentrations of airborne pollutants such as volatile organic compounds and nitrogen oxides and as photocatalyst coating which assist in deactivation of bio-contaminants. In this investigation nano-TiO2 and pigmentary TiO2 were synthesized using titanyl sulfate precursor, which can easily be produced by Sri Lankan ilmenite with sulfuric acid according to the sulfate process. Synthesized nano-TiO2 was characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning transmission electron microscopy (STEM) and scanning electron microscopy (SEM) methods. The photocatalytic activity of nano-TiO2 was assessed by the degradation of bromothymol blue in aqueous solution. Nano-TiO2 coated on glass showed a higher photocatalytic activity and self cleaning effect that can effectively be used in building envelops