Photooxidation of organic compounds by mesoporous silica functionalized with rose bengal

Abstract

The reuse of waste and the use of renewable materials are of great environmental and economic interest. With that in mind, the synthesis of mesoporous silica can be performed using rice husk ash, which is an industrial waste generated in large quantities. This mesoporous material can be functionalized with photoactive molecules, enabling application in photocatalysis. In this work, we used mesoporous silica nanoparticles functionalized with rose bengal dye (RB) for photooxidation reactions of organic molecules, such as the antibiotic cefuroxime 1-acetoxyethyl ester (cefuroxime axetil). The characterization results showed the formation of one-dimensional channels with uniform size and two-dimensional hexagonal arrangement, with surface area and pore diameter of 230 m² g⁻¹ and 5 nm, respectively. The infrared and UV-Vis spectroscopy indicated the functionalization of silica with photoactive molecules. Finally, SBA-15/RB was applied for the photooxidation of ascorbic acid and antibiotic cefuroxime axetil under irradiation with green light, proving to be efficient for the degradation of cefuroxime axetil. Investigation of the reactive oxygen species involved in photodegradation showed that the photooxidation mechanism mainly involves singlet oxygen.