PIM-based mixed-matrix membranes containing MOF-801/ionic liquid nanocomposites for enhanced CO2 separation performance

In this work, we fabricated PIM-based mixed matrix membranes (MMMs) containing MOF-801/ionic liquid nanocomposites to enhance CO 2 separation performance of pure polymer membranes. All membranes and MOF-801/ionic liquid nanocomposites were prepared by solution casting method and wet impregnation, respectively. The samples were analyzed by SEM, XRD , FTIR, TGA and Nitrogen adsorption-desorption measurements. The nanocomposites are composed of metal-organic framework (MOF) MOF-801 and ionic liquid (IL) adsorption capacity. MOF-801 can well control the dispersion of IL in the polymer matrix , which is conducive to exposing more active sites in the nanocomposites to improve the CO 2 adsorption selectivity of MOF-801/ionic liquid nanocomposites. At the same time, the porous structure of nanocomposites also enhances the gas adsorption and diffusion, thereby improving the gas separation performance. Compared with pure PIM-1 membranes, the CO 2 permeability and CO 2 /N 2 selectivity of IL@MOF/PIM-5% MMMs was increased by 129% and 45% (CO 2  = 9420 Barrer, CO 2 /N 2  = 29）, respectively. Compared with MOF-801/PIM-1 MMMs, the permeability of CO 2 decreased slightly but the selectivity of CO 2 /N 2 increased from 27 to 29. The aging test showed that the CO 2 permeability of MMMs could remain above 70% after 90 days. The anti-plasticization performance of MMMs has also been significantly improved. The CO 2 separation performance of IL@MOF/PIM-5% MMMs significantly exceeded the 2008 Robeson upper bound, showing excellent gas separation performance and working stability.