Effect of silica/titania ratio on enhanced photooxidation of industrial hazardous materials by microwave treated mesoporous SBA-15/TiO2 nanocomposites

Abstract

In this study microwave assisted technique has been adopted for the synthesis of different weight ratios of TiO2 dispersed on Santa barbara amorphous-15 (SBA-15) support. Morphological study revealed TiO2 particles (4–10 nm) uniformly distributed on SBA-15 while increases in SBA-15 content results in higher specific surface area (524–237 m2/g). The diffraction intensity of 101 plane of anatase polymorph was seen increasing with increase in TiO2 ratio. All the photocatalysts were having a mesoporous nature and follow the Langmuir IV isotherm, SBA-15 posses the highest pore volume (0.93 cm3 g−1) which consistently decreased with TiO2 content and was lowest (0.50 cm3 g−1) in case of 5 wt% of TiO2 followed by P25 (0.45 cm3 g−1) while pore diameter increased after TiO2 incorporation due to pore strain. The photocatalytic activity of the nanocomposites were analysed for the photodegradation of alizarin dye and pentachlorophenol under UV light irradiation. The reaction kinetics suggested the highest efficiency (98 % for alizarin and 94 % for PCP) of 5 wt% TiO2 compared to other photocatalysts, these nanocomposites were reused for several cycles, which is most important for heterogeneous photocatalytic degradation reaction. This study demonstrates the synthesis of silica embedded TiO2 nanocomposites by microwave assisted technique and their catalytic influence on degradation of organic dyes and pollutants. Higher loading of titania (SBA-15/TiO2, 1:5) results better catalytic performance than commercial nano TiO2 (P25).