A highly selective polybenzimidazole-4,4-(hexafluoroisopropylidene)bis(benzoic acid) membrane for high-temperature hydrogen separation

Abstract

A polymeric gas separation membrane utilizing polybenzimidazole based on 4,4-(hexafluoroisopropylidene)bis(benzoic acid) was prepared. The synthesized membrane has an effective permeating area of 8.3 cm(2) and a thickness of 30 +/- 2 mu m. Gas permeation properties of the membrane were determined using H-2, CO2, CO, and N-2 at temperatures ranging from 24 degrees C to 200 degrees C. The PBI-HFA membranes not only exhibited excellent H-2 permeability, but it also displayed superior gas separation performance particularly for H-2/N-2 and H-2/CO2. The permeation parameters for both permeability and selectivity [PH2 and (H-2/N-2); PH2 and (H-2/CO2)] obtained for the new material were found to be dependent on trans-membrane pressure difference as well as temperature, and were found to surpass those reported by Robeson in 2008. (c) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42371.