Poly(ethylene oxide)/Ag ions and nanoparticles/1-hexyl-3-methylimidazolium tetrafluoroborate composite membranes with long-term stability for olefin/paraffin separation

RSC Advances Pub Date: 2019-02-06 DOI: 10.1039/C8RA09274E

Abstract

A poly(ethylene oxide)(PEO)/AgBF4/1-hexyl-3-methylimidazolium tetrafluoroborate (HMIM+BF4?) composite membrane that exhibits long-term stability was prepared for olefin/paraffin separation. The membrane was prepared by simply adding AgBF4 and HMIM+BF4? to a solution of PEO. Long-term stability testing showed that the separation performance of the membrane is maintained for ≈100 h owing to the Ag NPs formed in the membrane, which are olefin carriers, being stabilized by HMIM+BF4?. In terms of separation performance, the PEO/AgBF4/HMIM+BF4? composite membrane exhibited a propylene/propane selectivity of 11.8 and a mixed-gas permeance of 11.3 GPU. We also investigated the factors that determine separation performance by comparison with a PEO/AgBF4/1-butyl-3-methylimidazolium tetrafluoroborate (BMIM+BF4?) composite membrane. The PEO/AgBF4/HMIM+BF4? composite membrane was characterized by scanning electron microscopy, FT-IR spectroscopy, ultraviolet-visible spectroscopy, thermogravimetric analysis, and Raman spectroscopy.

Graphical abstract: Poly(ethylene oxide)/Ag ions and nanoparticles/1-hexyl-3-methylimidazolium tetrafluoroborate composite membranes with long-term stability for olefin/paraffin separation
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