Tailored interfacial microenvironment of mixed matrix membranes based on deep eutectic solvents for efficient CO2 separation

Abstract

CO2 separation process based on mixed matrix membranes (MMMs) is considered as an effective way to mitigate global warming. However, due to the phase difference between inorganic fillers and polymers of MMMs, it is easy to produce non-ideal structures that are not conducive to gas separation. In this work, a novel deep eutectic solvent (DES) was developed to modulate the microenvironment in MMMs for efficient CO2 separation. Tailored DES as the third component can effectively avoid filler agglomeration after being introduced into the membrane. Compared with the binary system, the CO2 permeability and selectivity of the ternary MMM are improved by 38% and 9%, respectively. And the separation performance of ternary membranes for the mixed gas also exceeds the Robeson upper bound 2008. The performance improvement is not only due to structural optimization, but the result of multi-factor synergy. The tailored DES has excellent CO2 affinity and can provide an additional facilitated transport pathway according to the DFT calculation results.