Functionalization of SBA-15 mesoporous silica with thiol or sulfonic acid groups under the crystallization conditions
✍ Scribed by L.M. Yang; Y.J. Wang; G.S. Luo; Y.Y. Dai
- Publisher
- Elsevier Science
- Year
- 2005
- Tongue
- English
- Weight
- 302 KB
- Volume
- 84
- Category
- Article
- ISSN
- 1387-1811
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✦ Synopsis
In order to prepare functionalized mesoporous materials with sulfonic acid groups used as solid acid catalysts or as separation materials, a simple secondary modification method has been developed. Based on our previous work, SBA-15 materials with a high surface silanol density were prepared by simultaneously removing templates and crystallizing under acidic and hydrothermal conditions. Then the functionalization of SBA-15 mesoporous silica with thiol groups and the oxidation of thiol to sulfonic acid groups were carried out under the same hydrothermal conditions with a dilute aqueous H 2 O 2 solution as the oxidizing agent. Furthermore, the idea of coupling functionalization and oxidation into one step was tested, and the functionalized SBA-15 materials with sulfonic acid groups (SO 3 H-SBA-15) that were successfully prepared had an acid exchange capacity reaching 1 mequiv of H + /g of SO 3 H-SBA-15 as determined by a corrective base titration. SO 3 H-SBA-15 characterized by FT-IR, NMR, XRD, nitrogen adsorption and desorption, TGA, and hydrothermal stability experiments, exhibited a good long-range order, high specific surface area (about 600 m 2 /g), uniform pore sizes (about 6 nm), and high thermal and hydrothermal stabilities. SO 3 Ag-SBA-15 via ion exchange of SO 3 H-SBA-15 with Ag + was used to remove dibenzothiophene (DBT) from octane. The adsorption capacity reached as high as 17.0 mg S/g of SO 3 Ag-SBA-15.