Polyzwitterion-grafted UiO-66-PEI incorporating polyimide membrane for high efficiency CO2/CH4 separation.

[Display omitted] • UiO-66-PEI@pSBMA particles were fabricated by Schiff's base and ATRP reaction. • PEI grafting on UiO-66-NH 2 can enhanced the interface morphology of MMMs. • Polyzwitterion can strongly bonded water to facilitate the transport of CO 2 molecule. • The PI/UiO-66-PEI@pSBMA MMM shows the optimum CO 2 /CH 4 selectivity of 60.32. In this study, UiO-66-NH 2 fillers were grafted with polyethyleneimine (PEI) and poly(sulfobetaine methacrylate) (pSBMA) and subsequently incorporated into a sythesized 6FDA-ODA matrix to prepare mixed matrix membranes (MMMs). XRD, FTIR, SEM and TGA characterization techniques were used to evaluate the structure and properties of UiO-66-PEI@pSBMA and MMMs. It was found that the introduction of branched PEI and pSBMA can not only avoided the agglomeration of UiO-66-NH 2 , but also improved the compatibility between the polymer matrix and filler particles. In addition, the UiO-66-PEI@PSBMA was able to bond with a noticeable amount of amino groups and water molecules, and to promote the transportation of CO 2 in the membrane. The resulting PI/UiO-66-PEI@pSBMA MMM achived remarkably enhanced gas perm-selectivity compared to pristine 6FDA-ODA membrane and exceeded the Robeson upper bound. The strategy of PEI and polyzwitterion post covalent modification for UiO-66-NH 2 provides an effective way to eliminate interface defects and enhance the gas separation of MMMs. [ABSTRACT FROM AUTHOR]