Enhanced CO2/CH4 Separation Performances of Mixed Matrix Membranes Incorporated with Two-Dimensional Ni-Based MOF Nanosheets

Blending porous inorganic fillers into polymers to fabricate mixed matrix membranes (MMMs) is an efficient method to acquire good-quality membranes for CO 2 separation and purification. The poor interface coupling between bulky filling particles and polymer phase in MMMs results in reduced mechanical strengths with low separation performances. The novel two-dimensional (2D) and ultrathin α-Ni(im) 2 nanosheets with high aspect ratios are herein synthesized and blended with Pebax MH 1657 to prepare MMMs. The larger contacting area and strong hydrogen bonding between α-Ni(im) 2 nanosheets and Pebax improve their compatibility to form defect-free MMMs. The ultrathin α-Ni(im) 2 nanosheets in MMMs can effectively enhance CO 2 /CH 4 selectivity based on molecular sieving. With the addition of 2 wt % of α-Ni(im) 2 nanosheets, the as-prepared MMMs exhibit CO 2 /CH 4 selectivity up to 33.4 with a permeability of 100.6 Barrer. Compared with pure Pebax membrane, the separation selectivity shows a 72% increase with no significant change in CO 2 permeability.