Amine-modified Carbon Aerogels for CO2 Capture

Ten different amines of different molar mass and structure were deposited from aqueous and methanolic solutions of different concentrations onto two types of carbon aerogel. Thermogravimetric analysis (TGA) was used to quantify the loading, thermal stability and CO2 capture capacity of the materials. Our results show that the amount of amine deposited did not depend on the solvent used, but was generally greater from more concentrated solutions, and increased with increasing molar mass. Deposition of amines was principally achieved by adsorption onto the mesopore walls, but without complete pore filling, and also, in some cases, by adsorption in the aerogel micropores. It was also concluded that the thermal stability of the amines deposited on the walls of the mesopores was independent of the solvent used, concentration or aerogel type. Preliminary studies of CO2 adsorption-desorption were carried out and a good correlation between In(C-n) and 1/T, where C-n is the capacity at temperature T, was found. This enabled direct comparison to be made with published results obtained at different temperatures, and it was found that those obtained in this work were highly comparable with others found for amine-impregnated porous materials with similar amine loadings.