It is an urgent act to limit greenhouse gas emissions to avoid the harmful effects of climate changes. In this work, the binary and ternary systems of guanidinium trifluoromethanesulfonate ([gua][OTf]) in N-methyldiethanolamine (MDEA) and/or water were examined as alternative solvents for gas treatment process. The thermodynamic properties including density, r, viscosity, h, thermal expansion, a p and physical solubility of CO 2 in the systems were measured as a function of molar composition with a temperature range of 293.2-333.2 K at 100-1000 kPa. The presence of [gua][OTf] accelerates CO 2 absorption process. The present study offers equations of correlation providing a reliable prediction of the binary and ternary systems as a function of concentration. The linear equation, quadratic equation, extended Arhenius equation and Henry's Law equation have been applied to assess the validity of the finding. The CO 2 solubilities in [gua][OTf] systems are found higher compared to other ILs in previous researches. Additionally, ANN modeling of the effective parameters was carried out and the composition of [gua][OTf] was proven as the key factor in maximizing the CO 2 solubility. 2014 Published by Elsevier B.V.