Effect of palladium ion on facilitated olefin transport through silver-polymer complex membranes

Abstract

This study examined the effect of palladium (Pd) ions on the performance and stability of silver-polymer complex membranes composed of AgBF(4) and poly(N-vinyl pyrrolidone) (PVP) for the separation of propylene/propane mixtures. The separation performances including the selectivity of propylene/propane and mixed gas permeance through the PVP/AgBF(4) membrane decreased continuously due mainly to the reduction of silver ions to silver nano-particles. On the other hand, upon the addition of Pd ions, enhanced membrane stability along with the higher separation performance was achieved. This demonstrates that Pd ions play a role in preventing the reduction of silver ions and participating directly in the facilitated propylene transport. UV analysis of the membranes shows that the rate of silver nano-particle formation was retarded significantly by the addition of Pd salts.