Improved pore connectivity by the reduction of cobalt oxide silica membranes

Ji, Guozhao, Smart, Simon, Bhatia, Suresh K. and Diniz da Costa, João C. (2015) Improved pore connectivity by the reduction of cobalt oxide silica membranes. Separation and Purification Technology, 154 338-344. doi:10.1016/j.seppur.2015.09.065

Author Ji, Guozhao
Smart, Simon
Bhatia, Suresh K.
Diniz da Costa, João C.
Title Improved pore connectivity by the reduction of cobalt oxide silica membranes
Journal name Separation and Purification Technology   Check publisher's open access policy
ISSN 1873-3794
Publication date 2015-11-05
Sub-type Article (original research)
DOI 10.1016/j.seppur.2015.09.065
Open Access Status Not Open Access
Volume 154
Start page 338
End page 344
Total pages 7
Place of publication Kidlington, United Kingdom
Publisher Pergamon Press
Collection year 2016
Language eng
Formatted abstract
This work investigated the permeation of binary gas mixtures in non-reducing (He/CO2) and reducing (H2/Ar) conditions at temperatures ranging from 200 to 500 °C. A common performance aspect under both non-reducing and reducing conditions was that the He and H2 purity in the permeate stream was independent of temperature for the tested binary gas mixtures, except at very high He/CO2 or H2/Ar concentrations (⩾90/10) in the retentate stream. Under non-reducing conditions, the transport of gases was consistent with molecular sieving properties of silica derived membranes, and He permeance was constant irrespective of the He/CO2 binary concentration tested. An anomalous H2 transport was observed under reduced conditions, as unexpectedly the H2 permeance was higher for gas mixtures instead of single gas. Further tests showed that H2 permeance increased 170% as the gas mixture changed from single H2 gas to H2/Ar gas mixtures. This was attributed to the experimental procedure, as the membranes were partially reduced each day and tested for gas permeation from pure H2 to lower H2 concentration in gas mixtures. Under these partial reducing conditions, H2 slowly reacts with the surface of the dense Co3O4 particle, thus forming a porous CoO region. The increase in H2 permeance was therefore attributed to improved pore connectivity between the silica structure and the porous CoO region.
Keyword Cobalt oxide silica
Gas separation
Hydrogen reduction
Pore connectivity
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2016 Collection
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Citation counts: TR Web of Science Citation Count  Cited 1 times in Thomson Reuters Web of Science Article | Citations
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