Microporous Niobia–Silica Membrane with Very Low CO2 Permeability

Authors

  • Vittorio Boffa Dr.,

    1. MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, Fax: (+31) 534893595
    2. Present address: Dipartimento di Chimica Generale e Chimica Organica, Università di Torino, Corso M. D'Azeglio 48, 10125 Torino, Italy
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  • Johan E. ten Elshof Dr.,

    1. MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, Fax: (+31) 534893595
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  • Andrei V. Petukhov Dr.,

    1. Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Research Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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  • Dave H. A. Blank Prof.

    1. MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands, Fax: (+31) 534893595
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Abstract

A sol–gel-derived microporous ceramic membrane with an exceptionally low permeability for CO2 from gaseous streams was developed and characterized. The sols were prepared from a mixture of niobium and silicon alkoxide precursors by acid-catalyzed synthesis. Microporous films were formed by coating asymmetric γ-alumina disks with the polymeric sol (Si/Nb=3:1), followed by calcination at 500 °C. The membrane consists of a 150-nm-thick layer with a Si/Nb atomic ratio of about 1.5. The single-gas permeance of small gas molecules such as H2, CH4, N2, and SF6 decreases steadily with kinetic diameter. Hydrogen, helium, and carbon dioxide follow an activated transport mechanism through the membrane. The permeance of CO2 in this membrane is much lower than that in pure silica, and its behavior deviates strongly from the general trend observed with the other gases. This is attributed to a relatively strong interaction between CO2 and adsorption sites in the niobia–silica membrane.

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