Mesocellular silica foam (MSU-F) supports were functionalized via wet impregnation with various amine and alcohol compounds for use as high-capacity adsorbents for CO2 separation. The effect of the amino, hydroxyl, and ether functional groups in the impregnating mixture on the CO2 adsorption capacity was investigated. Chemical adsorption was controlled by the composition of the compounds, and the blending effect on the adsorption performance was dependent on the temperature. MSU-F (30 wt.%) impregnated with a mixture of tetraethylenepentamine (40 wt.%) and aminoethylethanolamine (30 wt.%) showed a high adsorption capacity of 5.4 mmol/g at 333 K for 15 kPa CO2.