Veiled metal organic frameworks nanofillers for mixed matrix membranes with enhanced CO2/CH4 separation performance

The interfacial compatibility between fillers and polymers essentially influences the separation performance of mixed matrix membranes (MMMs). In this work, an one-pot synthesized functional layer veiled zeolite imidazolate frameworks-67 (VZIF-67) was used as an efficient nanofillers to fabricate MMMs via physical blending with 6FDA-Durene polyimide. Benefiting from the CO 2 affinity from functional layer and the intrinsic characteristics of porous nanofillers, significant enhancement on separation performance was observed on the resultant MMMs. Specifically, the optimized VZIF-67 MMMs (30 wt% loading) exhibited CO 2 /CH 4 selectivity of 32.5 with CO 2 permeability of 1210 Barrer, which is 1.7 and 1.5 times higher than those of the control membrane, respectively. More importantly, the surface organic attribute and abundant amine groups of VZIF-67 reinforced the interfacial compatibility between the nanofillers and polymer matrix, leading to a doubled CO 2 /CH 4 selectivity compared with the ZIF-67 MMMs. Overall, the performance of the VZIF-67 membrane toward CO 2 /CH 4 separation surpasses the 2008-updated Robeson upper bound. These results indicate the functionalization strategy on porous nanofillers is a promising approach to fabrication of high performance of MMMs.