Pre-anchoring matrix onto zeolitic imidazolate frameworks towards defect-free mixed matrix membranes for efficient CO2 separation

Abstract

Combined with the specific advantages of continuous polymer phase and dispersed filler phase, mixed matrix membranes (MMMs) possess the potential to serve as the next generation membrane materials. However, the further development of MMMs is hindered by a variety of challenges, such as the structural stability of fillers during processing, the homogeneity during the dispersion, the non-ideal interfacial morphology between matrix and filler. In this work, a strategy for pre-anchoring polymeric matrices to fillers was proposed, the amino group was introduced to ZIF-8 framework (ZIF-8-NH2) by mixed ligand method based on the principles of reticular chemistry, and the ZPX fillers were fabricated by pre-anchored Pebax onto the ZIF-8-NH2, the unique ZIF-8/pre-anchored Pebax/Pebax interfacial structure was fabricated. The as-prepared Pebax/ZPX-5(10) MMMs exhibited a competitive performance in CO2 capture: high CO2 permeability for 146.4 Barrer, excellent CO2/N2 selectivity for 88.3, which improved by 269.1% and 187.1% respectively, compared with Peabx membrane, the index of filler enhancement (Findex) was 2.79, and the Robeson upper bound (2008) was successfully surpassed. Our pre-anchoring strategy provided an alternative answer for the facile fabrication of voids-free MMMs.