Photocatalytic degradation of pharmaceutical pollutants using zinc oxide supported by mesoporous silica

Abstract

The preparation of mesoporous silica supported zinc oxide photocatalyst (MS/ZnO) was carried out using the direct and indirect approaches (impregnation) in solvent media and grinding approach (mechanochemical) in a solvent-free media. This showed the dissemination of zinc oxide nanoparticles over mesoporous substrates that associated with the formation of a secondary phase of ZnO crystallites on the mesoporous materials. Consequently, a noticeable reduction of the total surface areas, pore volume and average pore size of mesoporous materials was affirmed due to a combination of ZnO nanoparticles, which entirely investigated via the N2 adsorption and desorption isotherms. In this respect, the efficiency of the photocatalysts was recognized using the photo-degradation reaction of Ibuprofen (IBP) as an assigned model of contaminant. Interestingly, the prepared photocatalysts using grinding approach (the mechanochemical approach, the focus of this research) sustained the best photocatalytic efficacy compared to the old-style wetness impregnation approach. This is also commensurate with a complete dispersion of ZnO on mesoporous material in a solvent-free media. Overall, the recent research has confirmed the merits and flexibility of the grinding approach in the preparation of MS/ZnO photocatalyst that incorporated with an efficient removal of solvent.