The time-course CO2 gas adsorption on pristine clays and dendrimer-loaded organoclays was analyzed by the computer simulation. Observed data of CO2 adsorption followed the Langmuir monolayer adsorption kinetics, when two and three adsorption sites were taken account for pristine clays and organoclays, respectively. The sites are on clay surfaces, clay interlayers and dendrimers. Amine-terminated dendrimer-loaded cation-exchange clays (laponite and sericite) displayed preferable adsorption of CO2 on dendrimer as well as on clay surface and interlayers. However, carboxylate-terminated dendrimer-loaded anion-exchange clay (hydrotalcite) reduced the CO2 adsorption in comparison with pristine clay because of less affinity of CO2 with carboxylate-terminals. This quantitative study suggests the new insights for the selective adsorption of CO2 molecules on solid adsorbents of amine-terminated organoclays. (C) 2015 Elsevier B.V. All rights reserved.