Enhancing the photoactivity of TiO 2 /SiO 2 monolithic catalyst and its reusability for wastewater treatment

Abstract

A series of TiO 2 /SiO 2 photocatalysts were successfully synthesized by the sol-gel method. The TiO 2 /SiO 2 monolith was also synthesized by dip-coating process. The crystalline structure of TiO 2 /SiO 2 powders was identified as pure anatase. The photocatalytic activity of the TiO 2 /SiO 2 powders was evaluated by photodegradation of 20 ppm methylene blue (MB) using a 26W lamp which has the wavelength in the visible light region under different Ti: Si molar ratios and calcination temperatures. The TiO 2 /SiO 2 powders which have Ti: Si molar ratio of 85:15 (TS15) and calcined at 550tC showed the highest photodegradation yield of 84 % after 3h irradiation. Furthermore, the 550˚C calcined TS15 monolith performed the MB degradation yield of 88.9 % after 3h irradiation and its photoactivity still remained after 4 recycle times. The results of this study demonstrated that the TS15 monolith photocatalyst has a reasonable efficiency in the degradation of methylene blue, it could be a promising photocatalyst for removal and degradation of organic pollutants.