Synthesis, properties and application in reactors of microporous membranes
- Univ. of Twente, Enschede (Netherlands); and others
Microporus inorganic membranes can be produced on porous ceramic supports. Examples are amorphous silica and zeolite membranes. These membranes show special properties and very high permeation values if sufficiently thin. Amorphous silica membranes are made by modification of mesoporous {gamma}-Al{sub 2}O{sub 3} membranes. After dipping into a silica sol the solvent phase penetrates into the support and silica sol particles fill pores in the membrane near-surface area. Calcination yields a membrane in which the top-layer is plugged with microporous silica. This results in very high separation factors for small molecules such as H{sub 2} with respect to larger molecules as C{sub 3}H{sub 8}. The fact that the active separation layer is porous and that it may have a thickness as low as 50 nm makes that very high permeabilities can be obtained. The actual micropore-size distribution depends on morphology and reactivity of the silica particles in the sol and the subsequent membrane preparation process. The morphology of the silica sol particles is studied with Small Angle X-ray Scattering and pore-size distributions by adsorption measurements of unsupported microporous silica. Typical microporous structures are obtained with silica particles with a random {open_quotes}polymeric{close_quotes} structure, a fractal dimension of 1.4 and a gyration radius of about 2 nm. Thin zeolite (silicalite) membranes (thickness 3-5 {mu}m) show similar high permeation values for H{sub 2} and CH{sub 4} as the amorphous silica membranes.
- OSTI ID:
- 213100
- Report Number(s):
- CONF-940713-; TRN: 96:001036-0017
- Resource Relation:
- Conference: 3. international conference on inorganic membranes, Worcester, MA (United States), 10-14 Jul 1994; Other Information: PBD: 1994; Related Information: Is Part Of ICIM{sub 3} 1994: Third international conference on inorganic membranes. Final program; PB: 148 p.
- Country of Publication:
- United States
- Language:
- English
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