The effect of pore structure on the CO₂ adsorption efficiency of polyamine impregnated porous carbons

The effect of polyamine impregnation on the CO₂ adsorption properties of two different porous carbons, one microporous and one mesoporous, was studied systematically. The pore filling during impregnation with polyamines was shown to result in a fraction of the unfilled micropore volume being blocked for gas adsorption. Thermal gravimetric analysis was used to compare the CO₂ capacity at 0.1 bar with respect to the carbon support type, the amount of amine loading, and the type of amine. A 12 fold increase in the CO₂ capacity was observed when the impregnated activated carbon was compared to the raw starting material. A heat of adsorption for amine impregnated support of ∼90 kJ mol^-1 was found, clearly indicating a chemisorption mechanism. The mesoporous material provided a more efficient support for the amine to interact with the CO₂. The interaction between low molecular weight amines and CO₂ showed a more efficient utilization of the basic groups in comparison to high molecular weight species.