Enhancing catalytic ozonation activity of MCM-41 via one-step incorporating fluorine and iron: The interfacial reaction induced by hydrophobic sites and Lewis acid sites

• Published in: Chemosphere (Oxford) Vol. 292; p. 133544
• Main Authors: Liu, Dongpo, Lin, Muxin, Chen, Weirui, Wang, Jing, Guo, Xingmei, Li, Xukai, Li, Laisheng
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.04.2022
• Subjects: Catalysis; F-Fe-MCM-41; Fluorine; Hydrophobic sites; Hydroxyl radicals; Ibuprofen; Iron; Lewis Acids; Ozone; Silicon Dioxide; Si–F bond; Water Pollutants, Chemical - analysis; Hydroxyl radicals; F-Fe-MCM-41; Hydrophobic sites; Si–F bond; Ibuprofen
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2022.133544

Fe-MCM-41 had been widely used as ozonation catalyst, however, the existence of large amount of hydrophilic silanol hindered its interfacial reaction with O3 and pollutants. To solve this problem, F–Fe-MCM-41 was synthesized by co-doping F and Fe into the framework of MCM-41 to replace silanol with Si–F groups through a one-step hydrothermal method. F introduced hydrophobic sites which contributed to more ibuprofen (IBP) chemisorption on the surface of F–Fe-MCM-41. Moreover, doping F also enhanced the acidity, which accelerated O3 decomposition into •OH. F–Fe-MCM-41/O3 exhibited notably activity with 96.6% IBP removal efficiency within 120 min, while only 78.5% and 80.9% in O3 alone and Fe-MCM-41/O3, respectively. Surface Lewis acid sites and metal hydroxyl groups were considered as important factors for O3 activation and •OH generation. F–Fe-MCM-41 exhibited excellent catalytic performance under acidic and alkaline conditions. Comparative experiments revealed that F doping improved the interfacial reaction, especially the interfacial electron transfer, which resulted in the high catalytic activity of F–Fe-MCM-41. F–Fe-MCM-41 possessed good stability and reusability, with only 5.7% decline for IBP removal in five successive cycles. Furthermore, the possible degradation path of IBP was proposed according to DFT calculation and GC-MS analysis. [Display omitted] •F–Fe-MCM-41 exhibited a good activity in catalytic ozonation for IBP.•Si–F bond successfully replaced silanol in the framework of Fe-MCM-41.•Hydrophobicity of F–Fe-MCM-41 contributed to more IBP chemisorption.•Strong Lewis acidity accelerated ozone decomposition to produce more .•OH;•The interfacial reaction played a dominant role in the catalytic ozonation process.