Development of rapid thermal processing of tubular cobalt oxide silica membranes for gas separations

This work shows for the first time that sol–gel derived cobalt oxide silica membranes can be produced on large scale, tubular supports through successful implementation of the rapid thermal processing (RTP) techniques. The combination of fast sol–gel methods and RTP techniques reduced the overall membrane fabrication time from a minimum of 7 days to approximately 12 h. The successful RTP technique was developed by changing the silica precursor from tetraethyl orthosilicate to ethyl silicate 40 and adjusting the nitric acid and water ratios in the sol–gel process. The optimized sol–gel conditions for the best membranes were found to deliver average He permeances of 3×10−7 mol m−2 s−1 Pa−1 and He/N2 permselectivities of 69 at 450 °C. This work has enormous potential for transforming the traditional processing pathways associated with sol–gel derived membranes for both research and commercial separation applications.