CO₂ absorption and ion mobility are investigated in a series of 50/50 wt% aqueous solutions of choline-based ionic liquids with different cations and anions: [N_1,1,4,2OH][Threo], [N_1,1,5,2OH][Threo], [N_1,1,6,2OH][Threo], [N1,1,5,2OH][β-ala] and [N_1,1,5,2OH][Tau]. The process of CO2 absorption was completed in an hour reaching maximum of absorption capacity 0.07–0.10 wt% to ionic liquid (by 0.4–0.6 molar ratios). A rapid CO₂ absorption is observed by the formation of solid product as a result of reaction between CO₂ molecule and the ionic liquid. Diffusion coefficients of the cation and anion in the mixture are comparable while the diffusivity of water molecules is found to be quite different from the ions. In the process of CO₂ absorption, an increase in the diffusivity of ions is observed due to the precipitation of solid products and depletion of ions contents in the liquid phase of the system. ¹³C NMR measurements of diffusivity of CO₂ enriched with ¹³C isotope showed that a part of the absorbed CO₂ remained in the liquid phase being physically and chemically bound to ions. The ionic liquid is re-cycled by evaporating water and releasing CO₂ molecules using vacuum and temperature.