Incorporation of Al3+ ions to promote the stabilization effect of (NH4)2SiF6 treatment on the hydrothermal stability of mesoporous SBA-15 zeolite

Chenglong Zou, Guanyu Sha, Yao Huang, Guoxing Niu, Dongyuan Zhao

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This work demonstrates an improved (NH4)2SiF6 treatment to enhance the hydrothermal stability of mesoporous SBA-15 zeolite. In this treatment, Al3+ ions are incorporated into SBA-15 zeolite first, then it is treated with 5 (NH4)2SiF6 solution according to 1 SiO2 of SBA-15 and finally washed with HCl (2 mol/L) to remove the pre-incorporated Al3+ ions. The obtained SBA-15 exhibits higher hydrothermal stability than that without pre-incorporated Al3+. Compared with the latter, the sample maintains a better ordered mesostructure and a larger surface area (271 m2/g) after hydrothermal treatment at 800 ?C for 12 h in 100 steam. The results show that incorporating Al3+ ions into SBA-15 zeolite before (NH4)2SiF6 treatment obviously promotes the stabilization effect of (NH4)2SiF6 treatment. The mechanism suggests that the incorporated Al3+ ions can effectively capture F- ions that have been released from (NH4)2SiF6, and thus reduce their etching into the SBA-15 zeolite framework. This ensures that the positive factors of (NH4)2SiF6 treatment, such as silicon insertion and surface hydrophobization by F- ions, play effective roles in the improvement of the hydrothermal stability of SBA-15 zeolite. This promoting effect of the Al3+ ions is closely related to the method that is used to introduce the Al3+ and the SBA-15 zeolite processing temperature
Original languageEnglish
Pages (from-to)1001-1008
Number of pages8
JournalChinese Journal of Catalysis
Issue number7
Publication statusPublished - Jul 2015
Externally publishedYes

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