A Fine‐Tuned Hollow Porous Metal–Organic Framework in Mixed‐Matrix Membranes for Benchmark Performance of CO2 Separation

Abstract

There is currently significant interest in introducing new materials that address present requirements and future possibilities inseparation processes. A particularly innovative fields in capitalizing of these expanding opportunities is membrane gas separation, which utilizes the emerging mixed matrix membrane (MMM) development. This strategy leverages the synergy of different materials to achieve the desired separation outcomes. Reasonable selection and suitable pairing of the polymer matrix with dispersed nanoparticles are crucial in the development of MMMs. This research introduces a new class of nanoparticles characterized by a porous hollow morphology to prepare high-performance MMMs. Here, for the first time, a hollow fluorinated metal-organic framework (H-F-MOF), known as H-SIFSIX-3-Cu with superior gas transport properties of molecular sieves, was successfully incorporated into the 6FDA-Durene polyimide (PI) matrix to investigate the effect of nanoparticle morphology on the performance of MMMs. The obtained H-F-MOF showed the advantages of tunable porosity, intrinsic low density, and favorable chemical properties, making it a promising candidate for gas separation. The optimal MMM containing 8 wt.% H-SIFSIX-3-Cu showed selectivities of 53.38 and 57.94 for CO2/N2 and CO2/CH4 separations, respectively, which are benchmark values in this field. The benchmark PI-based membrane presented in this work set a new record, far exceeding the Robeson’s upper limits and all PI-based membranes reported to date.