A Uniformly Oriented MFI Membrane for Improved CO2 Separation

• Published in: Angewandte Chemie International Edition 2014-03, Vol.53 (13), p.3492-3495
• Main Authors: Zhou, Ming, Korelskiy, Danil, Ye, Pengcheng, Grahn, Mattias, Hedlund, Jonas
• Format: Article
• Language: English
• Subjects: carbon dioxide; Chemical Technology; gas separation; Kemisk teknologi; membranes; thin films; zeolites
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201311324

Membrane separation of CO2 from natural gas, biogas, synthesis gas, and flu gas is a simple and energy‐efficient alternative to other separation techniques. But results for CO2‐selective permeance have always been achieved by randomly oriented and thick zeolite membranes. Thin, oriented membranes have great potential to realize high‐flux and high‐selectivity separation of mixtures at low energy cost. We now report a facile method for preparing silica MFI membranes in fluoride media on a graded alumina support. In the resulting membrane straight channels are uniformly vertically aligned and the membrane has a thickness of 0.5 μm. The membrane showed a separation selectivity of 109 for CO2/H2 mixtures and a CO2 permeance of 51×10−7 mol m−2 s−1 Pa−1 at −35 °C, making it promising for practical CO2 separation from mixtures. Porous chorus: An MFI membrane with a uniform b‐axis orientation and 0.5 μm thick was prepared by the growth of an MFI monolayer in a tetrapropylammonium fluoride gel on a porous alumina substrate. The MFI membrane has a CO2/H2 separation selectivity of 109 and a CO2 permeance of 51×10−7 mol m−2 s−1 Pa−1; it separated a CO2/H2 mixture at a feed pressure of 9 bar and no sweep gas was used.