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Relationship between the Mesoporous Intermediate Layer Structure and the Gas Permeation Property of an Amorphous Silica Membrane Synthesized by Counter Diffusion Chemical Vapor Deposition
Author(s) -
Nagano Takayuki,
Fujisaki Shinji,
Sato Koji,
Hataya Koji,
Iwamoto Yuji,
Nomura Mikihiro,
Nakao ShinIchi
Publication year - 2008
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2007.02073.x
Subject(s) - permeation , amorphous solid , permeance , mesoporous material , diffusion , chemical engineering , membrane , chemical vapor deposition , materials science , porous glass , partial pressure , chemistry , porosity , oxygen , nanotechnology , organic chemistry , catalysis , composite material , thermodynamics , biochemistry , physics , engineering
An amorphous silica membrane with an excellent hydrogen/nitrogen (H 2 /N 2 ) permselectivity of >10 000 and a He/H 2 permselectivity of 11 was successfully synthesized on a γ‐alumina (γ‐Al 2 O 3 )‐coated α‐alumina (α‐Al 2 O 3 ) porous support by counter diffusion chemical vapor deposition using tetramethylorthosilicate and oxygen at 873 K. An amorphous silica membrane possessed a high H 2 permeance of >1.0 × 10 −7 mol·(m 2 ·s·Pa) −1 at ≥773 K. The dominant permeation mechanism for He and H 2 at 373–873 K was activated diffusion. On the other hand, that for CO 2 , Ar, and N 2 at 373–673 K was a viscous flow. At ≥673 K, that for CO 2 , Ar, and N 2 was activated diffusion. H 2 permselectivity was markedly affected by the permeation temperature, thickness, and pore size of a γ‐Al 2 O 3 mesoporous intermediate layer.