Ionic liquid-modified hollow microspheres of tartaric acid-anion intercalated LDH in PIM-1 membranes for superior CO2/N2 separation

The performance of mixed matrix membranes (MMMs) depends largely on the structure and composition of incorporated nanofillers. However, it remains challenging to achieve efficient separation performance with uniform filler dispersion and strong interfacial compatibility within the polymer matrix. In this study, an ionic liquid-modified hollow microsphere of tartaric acid anion-intercalated layered double hydroxide (IL@HMS TA-LDH) was designed and embedded into a PIM-1 matrix to fabricate IL@HMS TA-LDH/PIM-1 MMMs for efficient CO 2 separation. The hollow microstructure and anion-rich interlayers of LDH provide multiple facilitated transport pathways for CO 2 significantly enhancing both permeability and selectivity. Experimental and theoretical calculation results confirm that IL modification on HMS TA-LDH not only improved the interfacial compatibility between the polymer and the filler but also enhanced CO 2 affinity and the CO 2 /N 2 selectivity. The resulting MMMs surpassed the 2019 Robeson upper bound and showed good stability. The separation efficiency of the optimal 5.0 % IL@HMS TA-LDH/PIM-1 MMMs was the best (CO 2 permeability was 8550.73 ± 367.54 Barrer, CO 2 /N 2 selectivity was 40.75 ± 1.83), outperforming most of the other reported MMMs. This work offers a new strategy for designing high-performance CO 2 capture membranes by combining hollow-structured LDH with functionalized ionic liquids.