Modeling carbon dioxide adsorption on polyethylenimine-functionalized TUD-1 mesoporous silica

► Polyethylenimine-loaded mesoporous silica is synthesized for CO2 adsorption. ► CO2 adsorption isotherms at different temperatures are collected. ► CO2 adsorption isotherms are modeled by means of the Langmuir equation. ► A good fit between model curves and experimental data is pointed out. ► Isosteric heat of CO2 adsorption versus adsorbent fractional coverage is estimated.