CO2 adsorption using solids with different surface and acid-base properties

The present work evaluated CO2 adsorption using solids with different porosity, crystallinity and acid-base properties such as zeolite Y, alumina, dolomite, ZnO and layered double hydroxides (LDH). The adsorbents were characterized by specific surface area measurements, XRD, TGA, NH3-TPD and CO2-TPD. The adsorption experiments were carried out in a continuous fixed bed reactor with online analysis by gas chromatography. The adsorption capacity was strogly influenced by the nature of the surface and to a lesser extent by the specific surface area of the material. The combination between high surface area and basic sites resulted in the highest CO2 adsorption capacity (159.1 mg/g(cat)) obtained for calcined LDH. The lowest CO2 adsorption was obtained with ZnO due to its low specific surface area and neutral surface. The strength and quantity of acid sites negatively influenced CO2 adsorption on solids with acidic properties.