Evaluation of CO2 separation performance with enhanced features of materials – Pebax® 2533 mixed matrix membranes containing ZIF-8-PEI@[P(3)HIm][Tf2N]

Zeolitic imidazolate framework (ZIF-8) was functionalized by polyethyleneimine (PEI) and subsequently decorated with ionic liquid (IL) – [P(3)HIm][Tf2N]. ZIF-8-PEI@IL/Pebax® 2533 mixed matrix membranes (MMMs) were fabricated to enhance the CO2 capture performance of Pebax membranes. The amino groups and IL in ZIF-8-PEI improved the gas separation performance of the MMMs due to the additional CO2 transporting pathways by using the reversible reaction with amino groups and the high affinity between IL and CO2. The modified ZIF-8 particles demonstrated enhanced interfacial interactions and compatibility between fillers and polymer matrix due to the presence of amino groups and IL, confirmed by the enhanced gas separation performance, improved elongation at break, and tensile strength of MMMs. Comparing with the pristine membranes, CO2 permeability of MMMs containing 15 wt% ZIF-8-PEI@IL increased by 123% to 285 Barrer, and the CO2/N2 and CO2/CH4 ideal selectivity increased from 17 and 12 to 76 and 25, respectively.