Influence of the carbonates formation on the CO2 adsorption

https://doi.org/10.1088/1468-6996/9/1/013007

“In the case of several cationic zeolites, the chemical adsorption of CO₂ is accompanied by the formation of carbonates including very stable monodentate or unidentate carbonates and bidentate carbonates, at their surface, due to the interaction of CO₂ with the oxygen bridging aluminum and silicon atoms [24, 35, 58–62]. Gallei and Stumpf [58] have described the formation of monodentate carbonate at the surface of zeolite CaY by a reaction involving three steps. In the first step, the CO₂ is polarized following its interaction with the neighboring Ca^{2 +} ions. After this, the atom of carbon of CO₂ attacks the oxygen bridging aluminum and silicon atoms, and this results in the rupture of aluminum oxygen bond, and the formation a stable monodentate carbonate species at the surface of zeolite (figure 4) [58, 59]. The presence of these carbonates might decrease the accessibility of CO₂ at a great part of the surface of zeolites and thereby contribute to limit its adsorption. This is notably the case of the unidentate surface carbonate species formed during the CO₂ adsorption on zeolite CaY that makes inaccessible approximately 20% of the surface cations [59].”