Bentonites impregnated with TiO_2 for photodegradation of methylene blue

摘要

Four bentonites and one diatomite from Rio Negro (Argentina) were used as supports for titanium oxide (TiO_2). The materials were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, textural analysis by nitrogen adsorption, elemental analysis and diffuse reflectance spectroscopy. The specific surface areas calculated by the BET method were 76,46,80, and 31 for the bentonites and 153 m~2/g for diatomite and were not changed by impregnation with TiO_2. SEM analysis revealed agglomerates, probably due to titania domains on the surface. The properties of the lamellar materials were maintained after TiO_2 impregnation, and all materials showed methylene blue photodegradation activity. The bentonites showed a higher activity than the commercial catalyst P25, likely due to the TiO_2 distribution and better accessibility.