NOVELTY - The method involves contacting a gas mixture with a mixture of ionic liquid including a cation and an anion, and a physical absorption solvent in an absorbent zone, where the mixture of ionic liquid and physical absorption solvent absorbs a component from the gas mixture, and the ionic liquid is added to the physical absorption solvent to alleviate viscosity issue. The mixture of ionic liquid and the physical absorption solvent is regenerated to remove absorbed components i.e. carbon dioxide, where the physical absorption solvent is non-corrosive and requires only carbon steel construction.    USE - Method for purifying a gas mixture e.g. natural gas, flue gas, syngas and shale gas (all claimed), for use in industrial applications.    ADVANTAGE - The method enables adding the ionic liquid to the physical absorption solvent so as to eliminate a need for refrigeration and effluent washing, while increasing capacity performance at a lower operating pressure without harming environment.    DETAILED DESCRIPTION - The physical absorption solvent is selected from a group consisting of dimethyl ether of propylene glycol, N-methyl-2-pyrrolidone, methanol, propylene carbonate, poly-propylene glycol di-methyl ether (PPGDME), poly-propylene glycol di-acetate (PPGDAc), poly-butylene glycol di-acetate (PBGDAc) with linear or branched C4 monomers, polydimethyl siloxane (PDMS), perfluoropolyether (PFPE), glycerol tri-acetate (GTA), acetone, methyl acetate, 1,4-dioxane, 2-methoxyethyl acetate, 2-nitropropane, n,n-dimethylacetamide, acetylacetone, 1-nitropropane, isooctane, 2-2-butoxyethoxy ethyl acetate, n-formylmorpholine, 2-butoxyethyl acetate and n-tert-butylformamide. The cation is selected from a group consisting of ammonium, tetraalkyl phosphonium, imidazolium, pyrazolium, pyridinium, pyrrolidinium, sulfonium, piperidinium, caprolactamium, guanidinium and morpholium. The anion is selected from a group consisting of halide, carboxylate, sulfonate, sulfate, tosylate, carbonate, acetate, phosphate, phosphinate, borate, acetate, cyanate, bis-trifluoromethyl sulfonyl-imide and aprotic heterocyclic anion.    DESCRIPTION OF DRAWING(S) - The drawing shows a graph representing relationship between isotherms using a physical absorption solvent as a control element and mixture of physical absorption solvent and ionic liquid.