Nano Science and Technology InstituteNano Science and Technology Institute
Nano Science and Technology Institute 2004 NSTI Nanotechnology Conference & Trade Show
Nanotech 2004
BioNano 2004
Program
Topics & Tracks
Sunday
Monday
Tuesday
Wednesday
Thursday
Index of Authors
Keynotes
Awards
Tutorials
Business & Investment
2004 Sub Sections
Sponsors
Exhibitors
Venue 2004
Proceedings
Organization
Press Room
Purchase CD/Proceedings
NSTI Events
Subscribe
Site Map
 
Nanotech Proceedings
Nanotechnology Proceedings
Supporting Organizations
Nanotech Supporting Organizations
Media Sponsors
Nanotech Media Sponsors
Event Contact
696 San Ramon Valley Blvd., Ste. 423
Danville, CA 94526
Ph: (925) 353-5004
Fx: (925) 886-8461
E-mail:
 
 

Nanostructure of a High-Permeability, Hydrogen-Selective Inorganic Membrane

S.T. Oyama, D. Lee, P. Hacarlioglu, Y. Gu and R.F. Saraf
Virginia Tech, US

Keywords: silica/alumina membrane, hydrogen permeation, statistical mechanics theory, solubility sites

Abstract:
This paper describes the preparation and properties of an inorganic membrane with permeability for H2 comparable to palladium and with over 99.9% selectivity over larger species like CO, CO2 and CH4. The membrane is a composite formed by the deposition of a thin, 20 nm SiO2 layer on an alumina support. The alumina support is obtained by the deposition of a boehmite sol on top of a porous substrate, so as to create a uniform structure with small pore sizes. The permeation of the small gas species, H2, He, and Ne through the silica layer is analyzed in detail in order to obtain insight about the transport mechanism and the structure of the silica. The order of permeance through the silica layer is highly unusual, He > H2 > Ne, following neither molecular weight nor size. The order of permeation is quantitatively explained using a statistical mechanics approach, which takes into consideration the density of solubility sites for the various species and the vibrational frequency of the species within the sites. An extension of the Masaryk-Fulrath treatment for glasses combined with the Percus-Yevick model is used to estimate the vibrational frequency (7.0x1012 s-1), solubility site density (3.0x1026 m-3 for H2) and the average distance between sites (0.84 nm). This is the first time an inorganic membrane has been described in detail at the nanometer level.

Nanotech 2004 Conference Technical Program Abstract

 
Sponsors
Nanotech Sponsors
News Headlines
NSTI Online Community
 
 

© Nano Science and Technology Institute, all rights reserved.
Terms of use | Privacy policy | Contact