Mixed-matrix membranes based on novel hydroxamate metal–organic frameworks with two-dimensional layers for CO2/N2 separation

Developing membranes with high gas separation performances is always desired for CO2 capture. Here we report the synthesis of a novel In(III)-MOF with chelating hydroxamate ligands that ensure structural stability, a new entry in the burgeoning class of hydroxamate-based MOFs. The material, namely SUM-9, along with its sister material SUM-1 (a Zr-hydroxamate MOF), were successfully incorporated in a series of Pebax 2533 based MMMs for CO2/N2 separation, with controllable composition. The permselectivity of the MMMs was experimentally determined in a comparative study and it was discovered that SUM-9 could achieve significantly improved CO2 permeability (539 Barrer) and CO2/N2 selectivity (24.69) with only 1 wt% loading in Pebax 2533, comparing to pristine Pebax films and MMMs with SUM-1.