Amine group graft ZIF-93 to create gas storage space to improve the gas separation performance of Pebax-1657 MMMs.

[Display omitted] • CO 2 was preferentially adsorbed due to the aldehyde group in the imidazolide skeleton of ZIF-93 zeolite. • CO 2 permeability and CO 2 /N 2 selectivity were improved with NH 2 -ZIF-93 addition. • Gas storage space is formed to improve gas separation efficiency of Pebax MMMs. In this study, amino organic compounds were grafted on the porous ZIF-93 surface by grafting modification to create a villous organic layer with CO 2 adsorption. Pebax-1657-based mixed matrix membrane (MMMs) is created using modified ZIF-93 as filler. The presence of this organic layer not only improves the adsorption of CO 2 gas by the filler, but also improves the rich storage space for the gas transport in the MMMs. Thus, the permeability and CO 2 /N 2 selectivity are improved. The MMMs with 10 wt% NH 2 -ZIF-93 showed the best separation performance, exhibiting distinct increases of 87.32% and 96.32% compared to primitive Pebax-1657 membrane, and passed Robeson's upper bound. [ABSTRACT FROM AUTHOR]