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Use of diffusion barriers in the preparation of supported zeolite ZSM-5 membranes

Yan, Yushan and Davis, Mark E. and Gavalas, George R. (1997) Use of diffusion barriers in the preparation of supported zeolite ZSM-5 membranes. Journal of Membrane Science, 126 (1). pp. 53-65. ISSN 0376-7388. doi:10.1016/S0376-7388(96)00263-3.

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Zeolite ZSM-5 membranes were prepared by in situ crystallization on porous α-Al_2O_3 disks that contained a diffusion barrier to limit excessive penetration of siliceous species into the alumina pores. The barrier was introduced into the alumina pores by impregnating the porous disk with a 1:1 molar mixture of furfuryl alcohol (FA) and tetraethylorthosilicate (TEOS), polymerizing the mixture retained in the disk, and carbonizing the resulting polymer at 600°C in N_2. Following carbonization, a partial carbon burn-off was carried out by catalyzed oxidation in 2% O_2N_2 at 600°C to generate a carbon-free region near the surface of the support. After zeolite crystallization, the remaining carbon and the organic structure directing agent were removed by calcination in air, at 500°C. It was found that pure carbon does not support zeolite growth while the solid obtained from a mixture of FA and TEOS does, due to the presence of dispersed silica. Membranes synthesized using barriers have n-butane flux and n-butane/isobutane selectivity 2.7 × 10^(−3) mol m^(−2) s^(−1) and 45, respectively, at 185°C, which are, respectively, ca. 1.6 and 4 times as large as those of membranes prepared without the use of barriers. Electron probe microanalysis (EPMA) and X-ray diffraction (XRD) revealed that the internal layer of the barrier-pretreated membrane has smaller thickness and higher crystallinity accounting for the increased flux and selectivity.

Item Type:Article
Related URLs:
URLURL TypeDescription
Davis, Mark E.0000-0001-8294-1477
Gavalas, George R.0000-0003-1468-6835
Additional Information:© 1997 Elsevier. Received 16 July 1996; revised 26 August 1996: accepted 12 September 1996. This research was supported by NSF grant CTS-9114829 and by the donors of The Petroleum Research Fund administered by the ACS.
Funding AgencyGrant Number
American Chemical Society Petroleum Research FundUNSPECIFIED
Subject Keywords:Inorganic membranes; Microporous and porous membranes; Zeolite ZSM-5; Diffusion barrier
Issue or Number:1
Record Number:CaltechAUTHORS:20151007-090424989
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Official Citation:Yushan Yan, Mark E. Davis, George R. Gavalas, Use of diffusion barriers in the preparation of supported zeolite ZSM-5 membranes, Journal of Membrane Science, Volume 126, Issue 1, 2 April 1997, Pages 53-65, ISSN 0376-7388, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:60842
Deposited By: George Porter
Deposited On:13 Oct 2015 21:28
Last Modified:10 Nov 2021 22:40

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