Transport and related (gas and vapour) separation in ceramic membranes

K. Keizer*, R.J.R. Uhlhorn, V.T. Zaspalis, A.J. Burggraaf

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

2 Citations (Scopus)


The main transport mechanisms in pores with a size of 3 to 100 nm are Knudsen and surface diffusion. According to Knudsen diffusion the transport of gases is inversely proportional to the square root of the molar mass. Surface diffusion is an additional mechanism to Knudsen diffusion and decreases, in most cases, the separation possibilities. Only surface diffusion of hydrogen (on metals) can increase the separation factors. Multilayer adsorption and capillary condensation can be very selective mechanisms for the separation of condensable gases from gas mixtures in pores of 2 to 10 nm. The application is limited because of the temperature/pressure regime which is needed for condensation and which may lead to technical inconveniences. In pores smaller than 2 nm and in zeolites micropore diffusion occurs. Transport of gases is activated with activation energies smaller than 25 kJ/mol for amorphous microporous systems. In silica-type of microporous toplayers H2,He and CO2 are transported much faster than any other type of gas. At 200°C a separation factor of over 200 is found for the mixture H2/C3H6. The transport mechanism in amorphous microporous materials is still under discussion. In this contribution the mentioned transport mechanisms will be discussed and their possibilities in gas and vapour separation will be illustrated.

Original languageEnglish
Title of host publicationInorganic Membranes ICIM2-91
Subtitle of host publicationProceedings of the 2nd International Conference on Inorganic Membranes - ICIM2-91
EditorsA.J. Burggraaf, J. Charpin, L. Cot
PublisherTrans Tech Publications Ltd
Number of pages12
ISBN (Print)9780878496259
Publication statusPublished - 1 Dec 1991
Event2nd International Conference on Inorganic Membranes, ICIM 1991 - Montpellier, France
Duration: 1 Jul 19914 Jul 1991
Conference number: 2

Publication series

NameKey Engineering Materials
PublisherTrans Tech Publications Ltd
ISSN (Print)1013-9826


Conference2nd International Conference on Inorganic Membranes, ICIM 1991
Abbreviated titleICIM


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