Graphene-containing microporous composites for selective CO2 adsorption

Abstract

Abstract Activated carbons obtained from polymers, Cu-containing metal-organic framework (MOF) and their composites with graphene oxide were synthesized using facile methods and tested for the selective adsorption of CO2 over N2 at ambient conditions. The prepared materials have been characterized by scanning electron microscopy, X-ray diffraction analysis and N2 adsorption. The Cu-containing metal-organic framework showed high CO2 uptakes up to 9.59 mmol g−1 and 5.33 mmol g−1 under 1 bar at 0 °C and 25 °C, respectively. The MOF composite with ~10 wt % of graphene oxide exhibited the best CO2 adsorption selectivity over N2 among all samples studied. Although, most graphene-containing composites feature lower CO2 adsorption capacities, they show an enhanced CO2/N2 selectivity in comparison to the bare samples. This paper contains a comparative study of the CO2/N2 selectivity calculated by using different methods. Additionally, CH4 adsorption, CO2/CH4 selectivity and isosteric heat of CO2 adsorption were evaluated for the selected sorbents. This study indicates that graphene-containing composites are potential materials for large-scale selective CO2 capture at ambient conditions.