High performance composite hollow fiber membranes for CO2/H2 and CO2/N2 separation

• The resultant composite membranes show good gas separation performance.
• The gutter layer is the key for achieving the high gas permeance.
• The interaction between ethylene oxide and CO2 accounts for high gas selectivity.
• The membranes have good potential for industrial applications.

The search for a clean energy source as well as the reduction of CO2 emissions to the atmosphere are important strategies to resolve the current energy shortage and global warming issues. We have demonstrated, for the first time, a Pebax/poly(dimethylsiloxane)/polyacrylonitrile (Pebax/PDMS/PAN) composite hollow fiber membrane not only can be used for flue gas treatment but also for hydrogen purification. The composite membranes display attractive gas separation performance with a CO2 permeance of 481.5 GPU, CO2/H2 and CO2/N2 selectivity of 8.1 and 42.0, respectively. Minimizing the solution intrusion using the PDMS gutter layer is the key to achieving the high gas permeance while the interaction between poly(ethylene oxide) (PEO) and CO2 accounts for the high selectivity. Effects of coating solution concentration and coating time on gas separation performance have been investigated and the results have been optimized. To the best of our knowledge, this is the first polymeric composite hollow fiber membrane for hydrogen purification. The attractive gas separation performance of the newly developed membranes may indicate good potential for industrial applications.