Present work analyses the behaviour and mass transfer of N-methyldiethanolamine (MDEA) in the removal process of carbon dioxide using a bubble column reactor (BCR) as gas-liquid contactor. The use of this type of equipment requires the interfacial area determination for the following mass transfer coefficient calculation based on absorption kinetics. In this work, a photographic method based on the bubble diameter determination, has been employed. The effect of contactor, operation conditions, liquid-phase nature and chemical reaction upon the mass transfer coefficient and interfacial areas have been analysed. (C) 2008 Elsevier B.V. All rights reserved.