Ionic Liquids‐Based Membranes for Carbon Dioxide Separation

Abstract

Ionic liquids (ILs) have gained wide‐spread focus owing to its negligible vapor pressure, low heat capacity, high thermal stability, and structural diversity. The solubility and selectivity toward carbon dioxide has made ILs a unique platform that possess the potential in gas separations. In particularly, combining functional ILs with membranes and porous supports is an efficient way to design task‐specific materials for CO2 separations. This minireview summarizes the developments and advances of ionic liquids‐based membranes for CO2 separations in recent three years, with an emphasis on the strategy of incorporating ionic liquids and CO2 separation performance.

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

“…[9,10] Recently, the supported ionic liquid membrane (SILM) has been reported for CO 2 separation. [11][12][13] SILM is a composite membrane, in which ionic liquids are occluded into a porous support. [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.…”

A Review on Ionic Liquid Gas Separation Membranes

“…To overcome the disadvantages of supported liquid membranes, scientists started to use ionic liquids instead of conventional solvents. Supported ionic liquid membranes (SILMs) have been the object of interest of many research groups for the last twenty years, as highlighted by the number of published reviews [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. The new types of SILMs created have high selectivity and permeability, and they combine the advantage of the stripping process by liquids with high solubility and the easy operation of membranes.…”

“…PILs preserve many of the beneficial properties of ILs such as thermal and chemical stability and ion conductivity. Moreover, PILs benefit from the intrinsic polymer properties [ 23 , 107 , 108 ]. In comparison with usual polyelectrolytes, the PILs are not soluble in water, but generally in polar organic solvents only [ 107 ].…”

“…[ 220 ]. Recently, the performance of PILs in gas separation was briefly reviewed in two scientific reports [ 23 , 221 ]. The pure gas permeabilities of PILs discussed further in this section are summarized in Table 5 and compared to the current state of art of gas separation membranes in Figure 7 .…”

Tunning CO2 Separation Performance of Ionic Liquids through Asymmetric Anions

“…However, recent pilot-scale trials at power plants in Germany showed that optimized SILMs could maintain their structural and process stability for 335 h [11]. The success of SILMs is well highlighted in recently published reviews [4,[12][13][14][15][16][17].…”