Chinese Journal of Catalysis ›› 2015, Vol. 36 ›› Issue (8): 1350-1357.DOI: 10.1016/S1872-2067(15)60857-9

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Facile solvothermal post-treatment to improve hydrothermal stability of mesoporous SBA-15 zeolite

Chenglong Zoua, Guanyu Shab, Haifang Gub, Yao Huangb, Guoxing Niua   

  1. a Department of Chemistry, Fudan University, Shanghai 200433, China;
    b Department of Materials Science, Fudan University, Shanghai 200433, China
  • Received:2015-02-10 Revised:2015-03-30 Online:2015-07-29 Published:2015-07-30
  • Supported by:

    This work was financially supported by the National Basic Research Program of China (973 Program, 2010CB226901, 2013CB934100) and the National Natural Science Foundation of China (20890123).

Abstract:

A simple and effective approach is demonstrated to improve the hydrothermal stability of mesoporous SBA-15 zeolite via a post-synthesis treatment of organic solvents, such as cyclohexane, toluene and n-butanol, at 157 or 190 ℃ for 6-24 h. After hydrothermal treatment at 800 ℃ for 12 h in 100% steam, the treated SBA-15 retained a well-ordered mesostructure, and retained high surface areas of 192-281 m2/g. SBA-15 zeolite treated by cyclohexane at 190 ℃ for 24 h showed the highest hydrothermal stability. The stabilization mechanism suggests that the solvothermal treatment has a significant promoting effect on dehydrating Si-OH groups in silica walls to form stable Si(OSi)4 from Si(OSi)2(OH)2 or Si(OSi)3OH groups. As a result, the wall defects after solvothermal treatment decrease, and the stability of silica is improved remarkably. This promoting effect strongly depends on the solvent properties, treatment temperature, and precursors of SBA-15 zeolite. The treatment by a nonpolar and low boiling point organic solvent displays the highest promoting effect on the calcined SBA-15 zeolite. This approach is simple, has low energy consumption and has potential application in the laboratory and for industry to prepare hydrothermally stable well-ordered mesoporous SBA-15 zeolite.

Key words: Mesoporous material, SBA-15 zeolite, Hydrothermal stability, Solvothermal treatment, Dehydration