Hydrothermal stability of MCM-48 improved by post-synthesis restructuring in salt solution

The hydrothermal stability of the mesoporous silica molecular sieves MCM-48 has been found to increase if the assynthesized materials containing surfa ctant are heated in an aqueous solution of salts. Although the optimum trea tment conditions depended on details of the synthesis procedures, this post -synthesis technique led to a significant improvement in the hydrothermal s tability of various MCM-48 materials that were synthesized using cationic s urfactants alone or cationic-neutral surfactant mixtures. These results wer e concluded as due to the restructuring effects of the pore walls by magic angle spinning Si-29 NMR spectroscopy, nitrogen adsorption and scanning ele ctron microscopy. (C) 2000 Elsevier Science B.V. All rights reserved.