Enhanced propylene/propane separation in facilitated transport membranes containing multisilver complex

Abstract Facilitated transport membrane containing a zero complex Ag4tz4 and 6FDA‐TMPDA was fabricated via a solution‐casting method and their separation performance toward C3H6/C3H8 was investigated. Ag4tz4 complexes were well dispersed in the polymeric matrix owing to the weak hydrogen bond between Ag4tz4 and 6FDA‐TMPDA which can efficiently improve their interface compatibility. The reversible π complexation between C3H6 and Ag+ facilitates the C3H6 transport in membranes, which is beneficial to achieve high C3H6/C3H8 permselectivity according to the density functional theory calculation. Remarkably, the best separation performance was achieved by the 10 wt% Ag4tz4 membrane, for which the C3H6 permeability is 22 Barrer and the C3H6/C3H8 selectivity reaches up to 43, surpassing the Robeson upper bound. In addition, the membranes also exhibit great long‐term stability (>120 h). The excellent separation performance together with the long‐term stability render the membrane to be an interesting candidate for C3H6/C3H8 separation.