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In the pursuit of advanced carbon capture methods, ionic liquid (IL)-based membranes have emerged as promising materials for CO2separation due to their high permeation and selectivity. This research focuses on the development of composite membranes with highly CO2selective ethanolamine-based ionic liquids and poly(vinyl alcohol) (PVA). ILs and membranes were characterized by water content, FT-IR, 1H, and 13C NMR. The addition of ethanolamine-based ILs and stream humidification promoted an outstanding increase of PVA membranes’ CO2permeability and CO2/CH4selectivity of 53× and 36×, respectively. Effects of transmembrane pressure (1.0 to 3.0 barg), temperature (313.15 to 343.15 K), and CO2:CH4ratio (10 to 40%) were studied. Effects of IL’s cations and alkyl chain length (anion) on CO2separation performance were studied via the production of PVA membranes with seven ethanolamine-based ILs. CO2permeabilities up to 209 barrer and selectivities up to 241 were obtained. The comparison of these membranes with some of the most promising materials in the literature indicates that the ethanolamine-based ILs + PVA membranes have moderate CO2permeabilities, associated with outstanding CO2/CH4selectivities.