Advanced mixed matrix membranes of Pebax embedded with amino acid ionic liquids@PIM core-shell composite nanoparticles for CO2 separation

Introducing the amino acid ionic liquids (AAILs) into polymeric membranes, have been a promising way to improve CO2 permeation-separation performance. A series of novel mixed matrix membranes (MMMs), based on Pebax 2533 and the AAILs@polymers of intrinsic microporosity (core-shell) composite nanoparticles (AAILs@PIM (core-shell) CNPs), were prepared. The composite nanoparticle was composed of the PIM as the dense shell and the AAILs as the core. The AAILs as the core provided high CO2 adsorption selectivity; and the AAILs covered by nanospheres avoided its loss. Moreover, the PIM shell and Pebax matrix also provided a good organic-organic interface in the MMMs. The chemical characterization of AAILs@PIM (core-shell) CNPs was performed by Fourier transform infrared spectroscopy. The morphology and structure of AAILs@PIM (core-shell) CNPs was investigated by transmission electron microscopy. The effect of incorporating the PIM HNPs on the chain segments of Pebax matrix was investigated by the differential scanning calorimeter. Gas transport property of the (AAILs@PIM (core-shell) CNPs)/Pebax MMMs was reported. Compared with the original Pebax membrane, the (AAILs@PIM (core-shell) CNPs)/Pebax MMMs displayed higher CO2/N-2 selectivity at the cost of a reduction in CO2 permeability because of the hydrogen bond of the AAILs-CO2 complexes. It is also found that increasing the temperature can eliminate the hydrogen bond of the AAILs-CO2 complexes. Therefore, at high temperature, the (AAILs@PIM (core-shell) CNPs)/Pebax MMMs exhibit both higher CO2 permeability and higher CO2/N-2 selectivity than the original Pebax membrane has. The outstanding CO2 permeation-separation performance shows great potential application to the flue gas treatment.