Influence of temperature on gas transport properties of tetraaminodiphenylsulfone (TADPS) based polybenzimidazoles

Kevin A. Stevens, Joshua D. Moon, Hailun Borjigin, Ran Liu, Ronald M. Joseph, Judy S. Riffle, Benny D. Freeman

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Abstract

Polybenzimidazoles have been the focus of increasing study due to their good H2/CO2 separation properties and high thermal stability. Gas transport properties of a series of polybenzimidazoles based on a tetraaminodiphenylsulfone (TADPS) monomer have been characterized at temperatures from 35 to 190 °C. Permeability increases with increasing temperature for all gases, and activation energies of permeation increase with increasing gas size with the exception of CO2. CO2 exhibits a lower activation energy of permeation than H2 or He, presumably due to strong sorption effects. Gas separations with TADPS-based PBIs are strongly size selective, with CO2/N2, CO2/CH4, and N2/CH4 selectivities decreasing with increasing temperature. However, H2/CO2 selectivities increase with increasing temperature due to a lower activation energy of permeation for CO2 than for H2. All PBIs tested move toward the upper right on the H2/CO2 upper bound as temperature increases. Estimated diffusivities increase significantly with temperature, indicating high activation energies of diffusion that are consistent with the strongly size-sieving nature of these materials.

Original languageEnglish
Article number117427
Number of pages10
JournalJournal of Membrane Science
Volume593
DOIs
Publication statusPublished - 1 Jan 2020
Externally publishedYes

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