A Highly Permeable Mixed Matrix Membrane Containing a Vertically Aligned Metal–Organic Framework for CO₂ Separation

Abstract

Delicately regulating the distribution morphology of a filler is an effective strategy to promote the separation performance of mixed matrix membranes (MMMs). Herein, we describe a highly permeable metal−organic framework (MOF)-based MMM comprising vertically aligned ZIF-8 (V-ZIF-8) and polysulfone (PSF). The V-ZIF-8 is distributed uniformly within the PSF matrix. With this unique distribution morphology of ZIF-8, the shortest gas transport pathways are formed in the membrane. Meanwhile, the molecular-sieving pores of ZIF-8 can allow CO 2 to pass through and crowding out N 2 . The obtained V-ZIF-8/PSF membrane shows a high CO 2 permeability of 89.7 Barrer and a CO 2 /N 2 selectivity of 30.0 that is stable over a period of 50 h. The CO 2 permeability is enhanced about 11.8 times than that of the pure PSF membrane. The results prove that the vertically aligned distribution morphology of an MOF in a polymer matrix is an effective method to improve the separation performance of a membrane, providing a new concept for designing more advanced membranes.

A roadmap to enhance gas permselectivity in metal–organic framework-based mixed-matrix membranes

“…In another effort of achieving structural alignment to facilitate molecular transport, a template strategy was used. 141 Using a vertically grown ZnO rod like structure (on PVDF), ZIF-8 MOF was grown as a vertically aligned array type structure and further modified with a polymer matrix (PSF) (Fig. 17a).…”

“…In another effort of achieving structural alignment to facilitate molecular transport, a template strategy was used. 141 Fig. 17…”

Recent advances in the application of zeolitic imidazolate frameworks (ZIFs) in environmental remediation: a review

“…Owing to the molecular-sieving property, ZIFs as mixed-matrix membranes are highly interesting for industrial separation of gases such as CO 2 /H 2 , 20,21,123–126 CO 2 /N 2 , 127–133 CO 2 /CH 4 , 134–138 CH 4 /H 2 , 139–141 CH 4 /N 2 , 18,142 and organic gases (propylene/propane 143,144 ).…”

Steering diffusion selectivity of chemical isomers within aligned nanochannels of metal-organic framework thin film

“…While the computational screening approaches for MOF-membrane design have received a signi cant interest, 26,27 experimental manipulation of diffusivity has remained challenging. Recent experimental efforts, such as downsizing MOF crystallite size, morphology control, 28 controlling nanochannel orientation [29][30][31] and employing novel heterostructure design [32][33][34][35][36] improve molecular diffusivity, however do not predictively tune the diffusivity.…”