This study presented experimental data of packed bed and rotating packed bed adsorption of carbon dioxide by dilute aqueous ammonia solutions. The heights of transfer units of packed bed were found to be 0.35 to 1.96 m; while the heights of a transfer unit of the rotating packed bed were in the range 0.08 to 0.40 m. Predictive models of the two processes were developed (model details and implications discussed elsewhere) based on the same set of thermodynamic and kinetic data for carbon dioxide into dilute aqueous ammonia solutions and existing mass transfer correlations for packed bed and rotating packed bed. The average absolute deviations between model predictions and experiments were found to be 9.4% for rotating packed bed data and 12% pack bed data.