Highly Stable Silver-Loaded Membrane Prepared by Interfacial Polymerization for Olefin Separation

Abstract

The separation of light olefins from paraffins by a silver-loaded facilitated transport membrane has received wide attention in recent years. However, the undesirable instability of carriers Ag+ has consistently restricted its further application. In this work, a silver-loaded facilitated transport membrane is developed by interfacial polymerization on PDMS/PSF support. A part of Ag+ in the prepared membrane is presented as silver­(I)-polyetheramine (Ag­(I)-PEA) complexes that can effectively enhance the stability of Ag+. To eliminate nonselective voids and bring more carriers (Ag+), secondary aqueous phase treatment was conducted. And the effect of PEA and TMC concentrations, ratio of PEA to AgNO3, as well as secondary aqueous phase treatment on the gas transport is systematically investigated. The results show that the facilitated transport of Ag+ to C3H6 can offset the increase in diffusion resistance induced by the incremental membrane thickness and cross-linking degree as well as the additional AgCl particles on the membrane. Finally, the optimum C3H6/C3H8 selectivity of the silver-loaded membrane is trebled over the membrane without silver. Remarkably, the TMC0.6%-PEA10%(AgNO3)10:9-2/PDMS/PSF membranes show great long-term stability of about 29 days. In this work, both monomer synthesis and preparation methods are facile and versatile, presenting a promising strategy for the preparation of silver-loaded membranes with a long-term separation property.