Abstract A protic ionic ethylenediamine liquid N,N-dimethyl-aminoethylammonium formate (DMEDAH formate) was evaluated for the removal of carbon dioxide from carbon dioxide and nitrogen mixed gas streams. This evaluation was conducted via a series of vapour–liquid equilibrium (VLE) experiments, wetted wall measurements and solvent contactor trials with the results compared to the performance of the industrial standard 30 wt% monoethanolamine (MEA). The VLE of the ionic liquid indicated that the sorption process included a chemical reaction component and is comparable to MEA. The mass transfer coefficient, calculated via the wetted wall column apparatus is an order of magnitude lower than MEA, which is likely due to the higher viscosity of the ionic liquid and its impact on carbon dioxide diffusivity. The solvent contactor trials indicated the solvent may be used in such an arrangement with good performance at low CO2 loadings, but would benefit from the use of alternative membrane materials.