Kinetics Investigation of the Photocatalytic Degradation of Acid Blue 92 in Aqueous Solution Using Nanocrystalline Tio2 Prepared in an Ionic Liquid

Abstract

TiO2 nanoparticles were prepared by the sol–gel process using 2-hydroxylethylammonium formate as an ionic liquid. Nanoparticles were crystallized at various temperatures (300-700°C). The products were characterized using X-ray diffraction (XRD), nitrogen adsorption – desorption isotherms and scanning electron microscopy (SEM) techniques. It was found that the resulting TiO2 nanoparticles had good thermal stability either to resist collapse or the anatase-to-rutile phase transformation during heat treatment. The photocatalytic activity of the nanocrystalline TiO2 was evaluated by the degradation of Acid Blue 92 (AB92) which is commonly used as a textile dye. The results showed that the degradation reaction of AB92 is first order with respect to AB92 concentration. The effect of parameters such as calcination temperature, initial dye concentration, TiO2 loading, pH, and concentration of added hydrogen peroxide on the rate of photocatalytic degradation was examined to optimise the operating conditions. The results showed that all these parameters influenced the degradation rate and those TiO2 nanoparticles prepared at 400°C had the highest photocatalytic performance. It was also found that under the optimized conditions, TiO2 nanoparticles prepared in the ionic liquid showed a much higher photocatalytic activity than the TiO2 nanoparticles prepared without the ionic liquid.