The solubility of carbon dioxide (CO2) in four ionic liquids, 1-ethyl-3-methylimidazolium L-(+)-lactate ([EMIM][LACTATE])-3-methyl-l-propylpyridinium bis[(trifluoromethylsulfonyl]imide ([PMPY] [TF2N]), 1-(4-sulfobutyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([(CH2)4SO3HMIm][TF2N]), 1-(4-sulfobutyl)-3-methylimidazolium hydrogen sulfate ([(CH2)(4)SO(3)HMIm][HSO4]), has been experimentally studied using the gravimetric microbalance method. (Carbon dioxide + IL) systems were studied at (313.15, 323.15 and 333.15)K over a pressure range of 100 mbar-20000 mbar. Experimental densities, Henry's Law constants, entropies and enthalpies of absorption were also reported. The results obtained showed that CO2 solubility diminished in the following sequence: [PMPY][Tf2N]>[EMIM] [LACTATE] > [(CH2)(4)SO(3)HMIm][TF2N] > [(CH2)(4)SO(3)HMIm][HSO4]. It was found that [PMPY][Tf2N] shows comparable CO2 solubility with ionic liquids that are considered promising such as [HMIM] [Tf2N], which makes this ionic liquid an attractive solvent for gas separation processes. CO2 solubility in the ionic liquids was well correlated using Peng-Robinson equation of state with a quadratic mixing rule and the nonrandom two-liquid (NRTL) model. (C) 2016 Elsevier B.V. All rights reserved.