Photocatalytic Activity of SnO2-Doped SiO2@TiO2 Nanocomposites

Abstract

Bisphenol A (BPA) is worldwide used to produce plastics and/or epoxybased foodstuff packages. But it is known that this compound is considered as a quite toxic contaminant due to (1) its similarity to the hormone estrogen and (2) its universal use in many industrial proceses. In our study the photodegradation of BPA stimulated by tin(IV) oxide-modified silica-titania nanocomposites was investigated. The reactions were characterized by the kinetic parameters (pseudo-first constant k 1 0.036-0.0896Á10for non-calcined and 0.0389-0.1144Á10 À2 min À1 for calcined photocatalysts), half-life time t 1/2 7.74-19.23 and 6.66-17.83 min for non-and calcined ones, respectively, allowing to determine both the weight k w and the specific surface area k s of each sample. It will be shown that most SnO 2 -doped silica-titania oxides are more active than commercially available TiO 2 (P-25, Degussa). The best results of BPA removal were obtained for 6 wt% addition of SnO 2 to both calcined and non-calcined photocatalysts.