Facilitated transport in ion-exchange membranes

Ions were used as mobile, membrane-bound carriers for selected gas species, these being introduced as the counter ions in ion-exchange membranes. For example, Ag+ ions were used as carriers for ethylene, and singly protonated ethylenediamine cations as carriers for CO2, both in cation-exchange membranes. Such preparations have the advantage that the carrier cannot easily be forced out of or washed out of the membrane, since it is retained there by strong electrostatic forces. This could be useful in practical gas separations, giving longer operating life under certain adverse conditions.