TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The absorbent solution comprises amine (10-99 wt.%); water (1-99 wt.%); and degradation inhibitor compound (5 ppm to 5 wt.%). The absorbent solution includes at least 39 wt.% of monoethanolamine. Preferred Components: The degradation inhibitor compound is pyridine compound of formula (III)-(VIII). preferably 2-mercaptopyridine, 2-mercapto-6-methylpyridine, N-oxide of 2- mercaptopyridine, 2-mercaptonicotinic acid, 6-mercaptonicotinic acid, 2-quinolinethiol, 5-(trifluoromethyl)-2-mercaptopyridine, 4-mercaptopyridine, 7-(trifluoromethyl)quinoline-4-thiol, 2-(2-pyridinyldisulfanyl)pyridine, 4-(4-pyridinyldisulfanyl)pyridine, a salt of 2-mercaptopyridine, a salt of 2-mercapto-6-methylpyridine, a salt of 2-mercaptopyridine N-oxide, a salt of 2-mercaptonicotinic acid, a salt of 6-mercaptonicotinic acid, a salt of 2-quinolinethiol, a salt of 5-(trifluoromethyl)-2-mercaptopyridine, 4-mercaptopyridine salt, 7- (trifluoromethyl)quinoline-4-thiol salt, 2-(2-pyridinyldisulfanyl)pyridine and 4-(4-pyridinyldisulfanyl)pyridine salt, preferably 2-mercaptopyridine, 2- mercaptonicotinic acid, sodium salt of 2-mercaptopyridine N-oxide, 2-mercapto-6-methylpyridine, 5- (trifluoromethyl)-2-mercaptopyridine and 4-mercaptopyridine. The amine is N,N,N',N',N"-pentamethyldiethylenetriamine, piperazine, monoethanolamine (preferred), diethanolamine, methyldiethanolamine, diisopropanolamine, diglycolamine, a salt of glycine or taurine salt. The gaseous effluent contains at least 500 ppm by volume of oxygen.X = H, alkali metal or alkaline-earth metal, monovalent or multivalent metal, an ammonium cation (NH4+) or resulting from protonation of an amine functional group, a phosphonium cation, 1-12C hydrocarbon group, or pyridine group of formula (A)-(F);R1-R8 = H, 1-12C hydrocarbon group, an sulfonic acid or ester, amine function or group of formula (-W1-Y1);W1 = S or O;Y1 = H, 1-12C group, an alkali metal or alkaline-earth, a monovalent or multivalent metal, an ammonium cation NH4+ or resulting from protonation of a amine function, or phosphonium cation.Preferred Process: In the process, the aqueous solution is implemented to absorb acidic compounds contained in the effluent of a group containing natural gas, flue gases, synthesis gas, refinery gases, gases obtained by Claus process tail, fermentation gases from biomass, gas cement and fume incinerator. The process comprises adding, in the aqueous solution, at least one degradation inhibitor compound comprising degradation group containing: 2-mercaptopyridine, 2-mercaptonicotinique acid, salt sodium of N-oxide of 2-mercaptopyridine, 2-mercapto-6-methylpyridine, 5-(trifluoromethyl)-2-mercaptopyridine and 4-mercaptopyridine to limit the degradation of monoethanolamine in aqueous solution and to capture carbon dioxide in the flue gases. EXAMPLE - No suitable example given.