This study investigates the thermophysical properties and CO₂ capture performance of hybrid solvents formed by blending protic ionic liquids (PILs) with alkanolamines. Eleven mixtures were prepared using three PILs—[Im/TfO], [MIm/TfO], and [Im/H2PO3]—and four alkanolamines—MEA, 2-MEA, 1-APA, and 3-APA—at a fixed molar ratio of 1:7. The thermal stability and temperature-dependent viscosity of the systems were characterized. CO2 absorption capacity was measured gravimetrically at 30 °C under atmospheric pressure, and the absorption mechanism was studied using FT-IR and 13C NMR spectroscopy. The cyclic performance and solvent stability during regeneration were evaluated at 60 °C and 100 °C. The results indicate that the [Im/TfO]:MEA mixture achieved the highest CO2 absorption capacity of 0.212 g CO2/g absorbent. Spectroscopic analysis confirmed the formation of carbamate species upon CO2 absorption. Regeneration at 100 °C resulted in progressive solvent mass loss, while a lower temperature of 60 °C provided stable performance over three consecutive cycles. The addition of 10 wt% water to the [Im/TfO]:MEA mixture reduced its viscosity by 48 % but also decreased the CO2 uptake by 24 %. The study demonstrates that hybrid PIL/alkanolamine systems, even with low PIL content, exhibit promising properties for CO2 capture applications.
