A membrane containing 7-23 nm polystyrene sulfonate domains was prepared using a reactive block polymer precursor and evaluated for its ammonia selectivity. The ammonia permeability is over 20.1 × 10-17 kmol m/(m2 s Pa) (600 barrers) at 25 °C and 2 × 105 Pa (2 bar) pressure; the selectivity for a mixed gas feed containing ammonia and nitrogen is over 90, about the same selectivity that is inferred from the pure gas feeds (the "ideal selectivity"). Variations in the sulfonated phase domain size and the degree of crosslinking in the membrane give permeabilities which increase with the average ammonia pressure and retain their selectivity at higher pressure. The results may have value in the separation of ammonia produced by the Haber-Bosch process.
Bibliographical noteFunding Information:
This work was largely supported by the US Air Force Office of Scientific Research (grant F49620-01-1-0333) and the US Department of Energy Grant 5-35908. This work was supported partially by the MRSEC Program of the National Science Foundation under Award Number DMR-0819885.
- Block copolymers
- Gas separation