A new MOF-505@GO composite with high selectivity for CO 2 /CH 4 and CO 2 /N 2 separation

Abstract Novel MOF-505@GO composites comprised of a copper-based metal-organic framework and graphite oxide (GO) were synthesized by a solvothermal method for effective separation of CO 2 /CH 4 and CO 2 /N 2 , which are challenging chemical separations in industry. The composites were characterized by various techniques including powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and porosity measurement through nitrogen adsorption at cryogenic temperature. Single component adsorption isotherm measurements of CO 2 , CH 4 and N 2 were performed at different temperatures. The selectivities of CO 2 /CH 4 and CO 2 /N 2 were estimated on the basis of ideal adsorbed solution theory (IAST). MOF-505@GO composites showed higher porosity and enhanced CO 2 adsorption compared to its parent compound MOF-505. MOF-505@5GO exhibited the highest CO 2 uptake of 3.94 mmol/g at 298 K and 100 kPa, having an increase of 37.3% in comparison with the parent MOF-505. The significant improvement of CO 2 uptakes could be attributed to not only new micropores and unsaturated metal sites formed in the MOF-505@GO, but also enhanced surface dispersive forces of the composites. The experimental adsorption isotherms of CO 2 , CH 4 and N 2 were well fitted with dual site Langmuir-Freundlich (DSLF) model. The CO 2 /CH 4 and CO 2 /N 2 adsorption selectivities were up to 8.6 and 37.2 at 298 K and 100 kPa, respectively, predicted by IAST. More strikingly, the composites showed excellent moisture stability, which was confirmed by PXRD analysis. These superior performances suggested that the MOF-505@GO composites are promising candidates for industrial CO 2 capture.