The preferential adsorption sites of HO on adsorption sites of CO at low temperature onto NaX and BaX zeolites

Abstract

Study of preferential adsorption sites of H 2 O on NaX and BaX zeolites was carried out after adsorption/desorption of carbon dioxide (CO 2 ). The profiles of CO 2 desorption revealed two distinct zones. The first one, at low temperature (T < 533 K), corresponding to physisorbed CO 2 where BaX zeolite has an energy of adsorption higher than that of NaX as well as strong interactions of adsorbent/adsorbate. The second one (533–623 K) corresponds to the chemisorbed CO 2 . The presence of water influences CO 2 adsorption. The effect is more important for NaX than for BaX. For NaX, water occupies the adsorption sites of CO 2 between 373 and 483 K. In contrast, BaX preserves a majority of adsorption sites of physisorbed CO 2 in the presence of water, in particular the adsorption sites located in the interval of temperature 423–533 K.