New Copolymer Architecture for Mixed Matrix Membranes with High Loadings of ZIF-8 for Enhanced CO₂ Permeability

Abstract

Membrane separation has emerged as a promising alternative to conventional separation processes for CO 2 capture. In this study, a new copolymer architecture corresponding to a PEObased grafted multiblock copolymer (PUI-g-PEDEGA1000) was compared to the corresponding nongrafted multiblock copolymer (PUI-g) for elaborating mixed matrix membranes with high loadings of metal organic framework ZIF-8. The new grafted multiblock copolymer architecture greatly improved the ZIF-8 dispersion and the ZIF-8/polymer interactions. The gas permeation properties were assessed by time-lag experiments for pure gases CO 2 and N 2 at 2 bar and 35 °C. For the highest ZIF-8 loading (40% vol), the new copolymer architecture led to the best CO 2 permeability (112 Barrer), corresponding to an improvement by a factor of 6 compared to the unloaded membrane, while the ideal selectivity α COd 2 /Nd 2 was maintained at a relatively high level (30.4). Finally, the CO 2 /N 2 permeability experimental results were compared with permeation data calculated from semipredictive ideal permeability models.