Characterization and investigation on the difference of hydrothermal stability for ordered mesoporous aluminosilicate sieves

Ordered hexagonal mesoporous aluminosilicates molecular sieves, designated as MSAMS-2A, MSAMS-2G and MSAMS-2, have been synthesized via re-crystallization of mesoporous SBA-15 within the diluted solution of aluminosilicate sol–gel, glycerol, and both of them, respectively. The three materials have been characterized by XRD, N₂ adsorption–desorption, FT-IR, FE-SEM, ²⁷Al MAS NMR and ²⁹Si MAS NMR, and the corresponding hydrothermal stability of these three sieves is in the order of MSAMS-2 > MSAMS-2G ? MSAMS-2A. The hydrothermal stability difference between MSAMS-2 and MSAMS-2G might be attributed to the synergistic effect of the higher condensation of silanol groups and insertion of all non-framework Al atoms into the framework of MSAMS-2. The hydrothermal stability of MSAMS-2G is higher than that of MSAMS-2A, which is likely because the high viscosity of glycerol will be in favor of the silanol groups interacting with zeolite-like subunits and moreover glycerol can act as a stabilizing guest molecule.