Separation properties of composite membranes
- Univ. of Colorado, Boulder, CO (United States); and others
Silicalite-alumina composite membranes were prepared by an in-situ zeolite synthesis method using an alumina membrane tube with a 5-nm-pore-diameter, {gamma}-alumina layer as a substrate. Single gas permeances of H{sub 2}, At, n-C{sub 4}H{sub 10}, i-C{sub 4}H{sub 10}, and SF{sub 6} were measured to characterize the silicalite membrane. These measurements were made from 300 to 737 K, and are compared to an alumina membrane without a silicalite layer. Permeances for the alumina membrane decreased as the temperature increased, and separation selectivities were lower than values expected for Knudsen diffusion. Transport through the alumina membrane was by Knudsen flow and surface diffusion. These permeance measurements indicated that transport was activated in the silicalite membrane, and activation energies ranged from 8.5 to 16.2 kJ/mol. Single gas permeation measurements were also obtained for larger hydrocarbons (n-pentane, n-hexane, cyclohexane and n-octane). Permeation measurements again indicated activated transport with activation energies ranging from 55 to 65 kJ/mol.
- OSTI ID:
- 126795
- Report Number(s):
- CONF-950402--
- Country of Publication:
- United States
- Language:
- English
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