Characterisation of templated xerogels for molecular sieve application

da Costa, Joao C.D., Lu, G. Q. and Rudolph, Victor (2001). Characterisation of templated xerogels for molecular sieve application. In: P Somasundaran and H Moehwald, Colloids and Surfaces A: Physicochemical and Engineering Aspects. 5th IUMRS International Conference on Advanced Materials, Beijing, People's Republic of China, (243-251). 13-18 June 1999. doi:10.1016/S0927-7757(00)00644-0


Author da Costa, Joao C.D.
Lu, G. Q.
Rudolph, Victor
Title of paper Characterisation of templated xerogels for molecular sieve application
Conference name 5th IUMRS International Conference on Advanced Materials
Conference location Beijing, People's Republic of China
Conference dates 13-18 June 1999
Proceedings title Colloids and Surfaces A: Physicochemical and Engineering Aspects   Check publisher's open access policy
Journal name Colloids and Surfaces A-Physicochemical and Engineering Aspects   Check publisher's open access policy
Place of Publication Amsterdam, The Netherlands
Publisher Elsevier
Publication Year 2001
Sub-type Fully published paper
DOI 10.1016/S0927-7757(00)00644-0
ISSN 0927-7757
Editor P Somasundaran
H Moehwald
Volume 179
Issue 2-3
Start page 243
End page 251
Total pages 9
Language eng
Abstract/Summary This paper presents the results of the characterisation of templated silica xerogels as precursor material for molecular sieve silica membranes for gas separation. The template agent integrated in the xerogel matrix is a methyl ligand covalently bended to the siloxane network in the form of methyltriethoxysilane (MTES). Several surface and microstructural characterisation techniques such as TGA, FTIR, NMR, and nitrogen adsorption have been employed to obtain information on the reaction mechanisms involved in the sol-gel processing of such molecular sieves. The characterisation results show the effects of processing parameters such as heat treatment temperature, and the concentration of the covalently bonded template on the development of the pore structure. It was found that calcination temperature significantly enhanced the condensation reactions thus resulted in more Si-O-Si groups being formed. This was also confirmed with the data of FTIR characterisation showing enhanced silicon bands at higher heat treatment temperatures. As a result of the promoted densification and shrinkable pore network the micropore volume also reduced with increasing methyl ligand molar ratio. However, the mean pore diameter does not change significantly with calcination temperature. While the contribution of the templates towards controlling pore size is less precise, increasing the methyl ligand molar ratio results in the broadening of the pore size distribution and lower pore volume. Higher template concentration induces the collapse of the xerogel matrix due to capillary stress promoting dense xerogels with low pore volume (C) 2001 Elsevier Science B.V. All rights reserved.
Subjects C1
291804 Nanotechnology
670707 Inorganic industrial chemicals
Keyword Chemistry, Physical
Silica Xerogel
Micropore
Molecular Sieve
Surface Characterisation
Sol-gel
Silica Membranes
Nmr
Si-29
Glass
Q-Index Code C1
Additional Notes Available online 22 December 2000.

 
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Created: Tue, 14 Aug 2007, 16:10:42 EST