Graphene oxide reinforced facilitated transport membrane with poly(ionic liquid) and ionic liquid carriers for CO2/N2 separation

Abstract

Abstract CO2 capture technologies are essential to achieve the global goal of carbon neutral and carbon negative. Membrane separations are energy-efficient compared to the adsorption/absorption processes with sorbents/solvents. However, little attention has been given to CO2 separation from air (direct air capture: DAC) or cabin air by membranes. In this study, a thin film composite type of facilitated transport membrane (FTM) with a functionalized ionic liquid (IL) carrier is developed. The selective layer is an IL-rich gel nanoconfined within the graphene oxide nanosheet framework. High performance of CO2 carrier-facilitated transport at conditions relevant to DAC (3090 GPU and CO2/N2 selectivity of 1180) and cabin air (620 GPU and CO2/N2 selectivity of 250) was demonstrated at 295\xa0K and 40% RH (1 GPU\xa0=\xa03.348\xa0×\xa010-10 mol m-2 s-1 Pa−1). The coupled permeation and selectivity represent the best performing FTM known under DAC conditions and promise potential for CO2 separation from air.