Development of solid polymer composite membranes based on sulfonated fluorocopolymer for olefin/paraffin separation with high permeability and selectivity

The PFSA-PP composite membrane was fabricated by deposition of a selective Nafion®-type poly(perfluorosulfonic acid) (PFSA) layer on a highly porous polypropylene (PP) film. The possibility of ethylene/ethane mixtures separation with the use of hydrogen and silver forms of the membrane was studied. A considerable influence of the gas mixture humidity on the ethylene permeability and selectivity of the membranes was demonstrated. The ethylene/ethane mixture separation factor reached 514, which is close to the values attained for Nafion® membranes, but with higher ethylene gas permeance of 28 GPU. The decrease in the selective layers thickness from 11 to 1 μm increases the ethylene permeance to 94.5 GPU with simultaneous decrease in the selectivity. As the ethylene content in the mixture decreases, the separation factors increase markedly.