A model of confined plunging liquid jet bubble column absorber is formulated and utilized for the interpretation of the experimental data obtained during steady-state absorption of concentrated gaseous CO2 in water. A strong variability of molar flux of the gas phase in the contactor was observed and taken into account. Two zones differing in mass transfer and mixing characteristics are distinguished within the contactor. Volumetric mass transfer coefficient in the mixing zone beneath the impingement point, is an order of magnitude greater than in pipe flow zone and determines the overall performance of the contactor.