Abstract
Silica sols have been prepared in an alcoholic solution by hydrolysis and condensation of TEOS (tetraethyl-ortho-silicate) molecules as a function of water and nitric acid concentration. The polymers are intended as precursors for ceramic, gas separation membranes. These molecules show fractal behavior as determined by SAXS (Small Angle X-ray Scattering). Microporosity of dried and calcined silica polymers is determined by N2-adsorption at 77 K. Fractal dimension and porosity increase with increasing acid concentration. Both the sol structure and the drying kinetics determine the porosity values. N2-adsorption isotherms are not very suitable for the determination of pore size distributions of microporous silica.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
A.F.M. Leenaars and A.J. Burggraaf, J. Colloid Interface Science105, 27 (1985).
C.J. Brinker and G.W. Scherer,Sol-Gel Science: The Physics and Chemistry of Sol-Gel Processing (Academic Press, San Diego, 1990), Chap. 3.
R.J.R. Uhlhorn, K. Keizer, and A.J. Burggraaf, J. Membrane Science66, 271 (1992).
R.S.A. de Lange, K. Keizer, and A.J. Burggraaf, I&EC Research (1995) accepted.
R. Aelion, A. Loebel, and F. Eirich, J. Amer. Chem. Soc.,72, 5705 (1950).
R.S.A. de Lange, J.H.A. Hekkink, K. Keizer, and A.J. Burggraaf, J. Non-Cryst. Solids (1995), accepted.
C.J. Brinker, R. Sehgal, S.L. Hietala, R. Deshpande, D.M. Smith, D. Loy, and C.S.S. Ashley, J. Membrane Science,94, 85 (1994).
R.S.A. de Lange, K. Keizer, and A.J. Burggraaf, J. Porours Materials1, 139 (1995).
R.S.A. de Lange, K.-N.P. Kumar, J.H.A. Hekkink, G.M.H. van de Velde, K. Keizer, A.J. Burggraaf, W.H. Dokter, H.F. van Garderen, and T.P.M. Beelen, J. Sol-Gel Science and Techn.,2, 489 (1994).
B.-N. Nair, W.E. Elferink, K. Keizer, and A.J. Burggraaf, J., Colloid Interface Science (1995), accepted.
W.E. Elferink, B.-N. Nair, R.M. de Vos, K. Keizer, and H. Verweij, J. Colloid Interface Science (1995), submitted.
J.E. Martin and A.J. Hurd, J. Appl. Cryst.20, 61 (1987).
W.H. Dokter,Transformation in Silica Gels and Zeolite Precursors (Ph.D. Thesis, Technical University of Eindhoven, 1994), p. 61.
K.G. Sharp, J. Sol-Gel Science and Technology2, 35 (1994).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nair, B.N., Elferink, J.W., Keizer, K. et al. Preparation and structure of microporous silica membranes. J Sol-Gel Sci Technol 8, 471–475 (1997). https://doi.org/10.1007/BF02436884
Issue Date:
DOI: https://doi.org/10.1007/BF02436884