N,N-Diethylethanolamine (DEEA), which can be prepared from renewable resources, represents a candidate alkanolamine for CO2 removal from gaseous streams. In this work, the reaction of CO2 with aqueous solutions containing N,N-diethylethanolamine (DEEA) was studied in a stirred cell reactor with a plane, horizontal gas-liquid interface, in the range of temperatures 298-308 K. The DEEA concentration in the aqueous solutions was varied in the range 2-3 kmol/m(3). The liquid-side mass transfer coefficient and a combined parameter comprising the reaction rate constant and the diffusivity and solubility of CO2 in DEEA solutions were evaluated. The effect of the addition of piperazine (PIP) as a possible absorption activator was studied, and it was found that even with a small amount of PIP (0.1 kmol/m(3)) added, the CO2 absorption rate increased.