Novel Fluid Ionic Liquid Composites with Self-Assembled Porosity and Chemical Sites for Facilitating CO2 Separation

Porous ionic liquid (IL) composites, such as impregnated,encapsulated,and porous ILs, are widely used for CO2 capture. However,IL-based adsorbents generally have relatively low IL loading, whichcannot fully exploit the unique advantages of ILs. Porous ILs withhigh IL loading over 90 wt % had high viscosity affecting mass transfer.Therefore, how to simultaneously avoid high viscosity and improvethe CO2 absorption rate and IL loadings is of great significant.Herein, a novel fluid IL composite with self-assembled porosity andchemical sites was originally proposed for the CO2 separation.It was prepared by introducing amino-acid IL (AAIL) [N-2222][Gly] as the dispersing phase, the mixture of [Emim][Tf2N] (IL1) and [HDBU][Im] (IL2) as the continuousphase, and silica H-20 as the emulsifier, which was named AAIL-H20-IL1/IL2. The results demonstrated that an excellentCO(2) capacity of 2.30 mmolCO(2)/g-sorbent was obtained(313 K/1 bar) with the highest IL loading of 98 wt % among the state-of-the-artvalue. Meanwhile, micro droplets and porous structures can effectivelyincrease the CO2 absorption rate. The superior CO2 capacity was deduced by the chemisorption of [N-2222][Gly]and [HDBU][Im] revealed by in situ FTIR and DFT calculation. In general,this work proposes a pioneer strategy to prepare fluid porous IL compositeswith ultrahigh IL loading for facilitating CO2 separation. Novel fluid ionic liquid composites withself-assembledporosity and chemical sites facilitate efficient CO2 separation.