Different Approaches for the Development of Low-Cost CO_2 Adsorbents

摘要

Different carbon materials were tested as precursors for the production of CO_2 adsorbents. The chemical modification of the surface of the prepared adsorbents was studied by means of three different approaches: impregnation with amines, electrophilic aromatic substitution, and heat treatment in the presence of ammonia. The samples were chemically characterized and the porous texture was evaluated from the N_2 adsorption isotherms at —196°C. The CO_2 adsorption capacities of the adsorbents at 25 and 100°C were evaluated in a thermogravimetric analyzer. In general, the incorporation of basic nitrogen functionalities enhanced the CO_2 capture capacities of the modified carbons, but this increase depended on the textural properties of the support and the surface modification methodology. CO_2 adsorption capacities of up to 111 mg CO_2/g at room temperature were attained. All the tested samples were completely regenerated when subjected to heat treatment at 100°C under inert atmosphere.