(380aj) Facilitated Transport Membranes for Highly Selective and Stable Olefin/Paraffin Separation.

Effective separation of olefin and paraffin is a significant challenge, given their comparable molecular sizes and other physical attributes. Facilitated transport membranes (FTMs) that employ metal ion carriers, typically Ag⁺, to chemically facilitate the transfer of olefin molecules, represent an alternative to energy-intensive distillation for this separation. Over the past decades, efforts have been made to develop FTMs with enhanced carrier-facilitated transfer capabilities while also ensuring membrane stability. In this study, a series of gel-like FTMs were developed using appropriate polymeric matrices that possess both metal-chelating and strong hygroscopic properties. The membrane matrices included chitosan and polyvinyl amine/polyvinyl alcohol blend, subjected to physical or chemical modifications during membrane formation. These membranes were effectively loaded with significant amounts of Ag ions for Ag-olefin complexation in a hydrated environment. This allowed the use of cost-effective AgNO₃ as an olefin carrier. All gel-like membranes were found to be stable in long-term operation. A slight deterioration in the separation performance due to water loss was observed, and it could be fully restored with a humidifier. These gel-like membranes showed great potential in terms of permeability and selectivity, stability, as well as cost-effectiveness, making them particularly suitable for olefin/paraffin separation.