Adsorption of carbon dioxide on graphene oxide supported layered double oxides

Adsorption of CO₂ on layered double oxides supported on graphene oxide has been studied under dry and wet conditions. In the first exposure to the adsorptive gas, the isotherms obtained for supported and unsupported materials are shown to fit to the Freundlich model indicating the existence of heterogeneous adsorption sites. After multiple temperature-swing cycles, the adsorption capacity decreased and the data is better described by the Langmuir model. The presence of graphene oxide is shown to reduce the loss of adsorption capacity, and helps to maintain the heterogeneity of the basic sites on the adsorbents. The use of wet gas mixtures was found to have a positive effect on the CO₂ adsorption capacity of the graphene oxide hybrids. The presence of residual sodium on the materials resulted in a Freundlich isotherm with increased adsorption capacity.