The mass transfer of the absorption of carbon dioxide bubble swarms into three different rheological fluids (Newtonian fluids, shear thinning fluids and viscoelastic fluids) were investigated experimentally. The volumetric liquid-phase mass transfer coefficients under different operating conditions were determined by using a carbon dioxide probe. The influences of gas flow rate and liquid properties on volumetric liquid-phase mass transfer coefficient were studied. Results indicated that the volumetric liquid-phase mass transfer coefficient increased with gas flow rate but decreased with increasing liquid apparent viscosity. Moreover, the viscoelasticity of liquid resulted in a decrease of mass transfer rate. A semi-empirical model was developed, the prediction by this model showed a satisfactory agreement with the experimental data in all three types of liquids studied. (c) 2012 Elsevier Ltd. All rights reserved.