Novel ZIF-300 Mixed-Matrix Membranes for Efficient CO₂ Capture

Abstract

Because of the high separation performance and easy preparation, mixed-matrix membranes (MMMs) consisting of metal-organic frameworks have received much attention. In this article, we report a novel ZIF-300/PEBA MMM consisting of zeolite imidazolate framework (ZIF-300) crystals and polyether block amide (PEBA) matrix. The ZIF-300 crystal size was effectively reduced by optimizing the hydrothermal reaction condition from ∼15 to ∼1 μm. The morphology and physicochemical and sorption properties of the synthesized ZIF-300 crystals and as-prepared ZIF-300/PEBA MMMs were systematically studied. The results showed that ZIF-300 crystals with a size of ∼1 μm maintained excellent preferential CO₂ sorption over N₂ without degradation of the crystal structure in the MMMs. As a result, uniformly incorporated ZIF-300 crystals highly enhanced both the CO₂ permeability and the CO₂/N₂ selectivity of pure PEBA membrane. The optimized ZIF-300-PEBA MMMs with a ZIF-300 loading of 30 wt % exhibited a high and stable CO₂ permeability of 83 Barrer and CO₂/N₂ selectivity of 84, which are 59.2% and 53.5% higher than pure PEBA membrane, respectively. The obtained performance surpassed the upper bound of state-of-the-art membranes for CO₂/N₂ separation. This work demonstrated that the proposed ZIF-300/PEBA MMM could be a potential candidate for an efficient CO₂ capture process.