Facilitated olefin transport membranes consisting of a polyvinylpyrrolidone (PVP)/AgCF3SO3/Al(NO3)(3) complex were prepared for the separation of a propylene/propane mixture. Very recently, Al(NO3)(3) was utilized to retard reduction of silver ions generated from AgBF4 In this study, the effect of Al(NO3)(3) on inhibiting the reduction of Ag+ ions generated from AgCF3SO3 was investigated, where AgCF3SO3 was used as a cost-effective alternative to AgBF4 in the olefin transport membranes. Incorporation of Al(NO3)(3) into the PVP/AgCF3SO3 complex membrane resulted in a selectivity of 5 and a permeance of 0.5 GPU for the separation of a propylene/propane mixture. Furthermore, the PVP/AgCF3SO3/Al(NO3)(3) complex membranes exhibited long-term stability even though AgCF3SO3 is easily reduced to silver nanoparticles. It was thus confirmed that Al(NO3)(3) played the role of a retardant for the reduction of Ag+ ions generated from AgCF3SO3 as well as from AgBF4. The coordination properties of the PVP/AgCF3SO3/Al(NO3)(3) complex membranes were characterized by X-ray photoelectron, Fourier transform (FT) infrared, and FT-Raman spectroscopy. (C) 2015 Elsevier B.V. All rights reserved.