A Review on Gas Separation Applications of Supported Ionic Liquid Membranes

Abstract

The selection of the separation process is a critical issue in the chemical industries. Among different conventional methods for the separation processes, supported liquid membrane (SLM)-based separation processes have been predicted as a promising option. However, the industrial use of supported liquid membranes based on conventional liquids is limited by their relative instability and short lifetime. The use of ionic liquids as a liquid membrane phase results in the stabilization of the SLMs due to their negligible vapor pressure, possibility of minimizing their solubility in the surrounding phases and greater capillary force associated with their high viscosity, which can reduce the displacement of liquids from micron pores under pressure. In this review, recent advances in supported membranes based on ionic liquids including issues such as methods of synthesis IL, methods of preparation of supported ionic liquid membranes and application of supported ionic liquid membranes in gas separation are presented.

Photothermal‐Responsive Microporous Nanosheets Confined Ionic Liquid for Efficient CO2 Separation

“…Owing to their near-zero vapor pressure, good chemical, and thermal stability, ionic liquids have been frequently used as the liquid media to construct the SILM. [14,17] As a prototype, the probably either infiltrates into the interlayer between two adjacent nanosheets or penetrate into the micropores of the Zr-Fc MOF. [22] According to the literatures, [24,27] the former one will result in an expansion of the interlayer and thus increase the membrane thickness.…”

“…[14] The intrinsic properties of ionic liquid, such as non-volatility, high viscosity, high thermal and chemical stability, [15,16] make the SILM advantageous in CO 2 separation over the traditional supported liquid membranes, which usually suffer from severe liquid loss caused by either volatilization or displacement during the use. [16,17] Several factors have been demonstrated to affect the final CO 2 separation efficiency. [18] Initial studies have been focused on the optimization of the composition of ionic liquids to enhance the CO 2 separation efficiency.…”

Molecular simulation study of CO2 and N2 absorption in a phosphonium based organic ionic plastic crystal

“…can enhance gas separation capabilities by improving both the permeability and selectivity for several industrially relevant gas mixtures. 2,4,9,10 This strategy is particularly effective for CO 2 separation as the quadrupole moment of the gas results in strong electrostatic interactions with the ions of the IL. 11 However, the IL/polymer structure can lose its robustness even at low pressures, 12 when the IL is partially forced out of the membrane by the gas.…”

Permeabilities of CO2, H2S and CH4 through Choline-Based Ionic Liquids: Atomistic-Scale Simulations

“…The results for the permselectivities are also given in Table 1. Both ILs show exceptionally high CO2/CH4 and H2S/CH4 selectivities as compared to supported ionic liquid membranes (SILMs) (see Reference [59] for a review on SILMs). For example, a maximum CO2/CH4 selectivity of 59 was reported for 1-ethyl-3-methylimidazolium/bis(trifluoromethanesulfonyl)amide ILs on a polymeric membrane support [60], whereas the cholin e-based ILs considered here show more than two orders of magnitude larger CO2/CH4 selectivity.…”