Facilitated transport of olefin through solid PAAm and PAAm-graft composite membranes with silver ions

Solid poly(acrylamide) (PAAm) composite membranes containing silver ions ha ve been investigated for olefin/paraffin separation. The propylene permeanc e increased significantly for a solid PAAm/AgBF4 composite membrane with in creasing loading amount of silver ions. Silver ions in solid PAAm form reve rsible complexes with propylene, resulting in the facilitated transport of propylene. The propylene selectivity of 100 over propane was obtained when the mole ratio of silver ions to acrylamide unit was 1. This high separatio n performance would be obtained predominantly because of the high loading o f the propylene carrier, silver ions. PAAm-graft/AgBF4 composite membranes were prepared in order to improve the gas permeance. Introduction of PAAm g rafts on a polysulfone microporous membrane surface was confirmed by FT-IR spectroscopy. The propylene permeance was increased through the PAAm-graft/ AgBF4 membranes compared to that through of the PAAm/AgBF4 composite membra nes, indicating the formation of ultra-thin top layer. (C) 2001 Elsevier Sc ience B.V. All rights reserved.