Enhanced CO2/N2 separation performance by using dopamine/polyethyleneimine-grafted TiO2 nanoparticles filled PEBA mixed-matrix membranes

Abstract Mixed matrix membranes (MMMs) were fabricated by incorporating synthesized titanium dioxide (TiO 2 ) nanoparticles into polyether block amide (PEBA) matrix to fabricate TiO 2 /PBEA MMMs for CO 2 /N 2 separation. The mesoporous channels of TiO 2 increased the density of active sites with high accessibility and also facilitate the diffusion of CO 2 in the gas separation process. Furthermore, amine groups are grafted onto the TiO 2 fillers via one step reaction with dopamine (DA) and polyethyleneimine (PEI). The modified TiO 2 fillers with abundant amine groups are conductive to transfer CO 2 owing to the reversible reaction occurred between CO 2 and amine groups. The effects of TiO 2 loading, DA/PEI modification on the morphology and CO 2 /N 2 separation performance of the resulting TiO 2 /PBEA MMMs were systematically studied. The results showed that the MMMs filled with 3 wt% DA-PEI-TiO 2 synthesized with DA/PEI mass ratio of 1/1 and PEI molecular weight of 1800 exhibited optimal separation performance with CO 2 permeability of 67 Barrer and CO 2 /N 2 selectivity of 101, surpassing the 2008 Robeson upper-bound.