Adsorptive separation of CH, H, CO, and N using fullerene pillared graphene nanocomposites: Insights from molecular simulations.

CONTEXT

The adsorptive separation performances of fullerene pillared graphene nanocomposites (FPGNs) with tunable micro and meso porous morphology are investigated for the binary mixtures of CH, H, CO and N by using grand canonical Monte Carlo (GCMC) simulations. Different fullerene types are considered in designs as pillar to investigate the effects of porosity on the gas separation performances of FPGNs, and the GCMC simulations are performed for an equimolar binary mixture of CO/H, CO/CH, CO/N and CH/H inspired by industrial gas mixtures. It is found that CO/N, CO/H and CH/H selectivity of FPGNs are about 72, 410 and 145 at 298 K and 1 bar, which are higher than those for several adsorbent materials reported.

METHODS

Five different FPGN models which contain covalently bonded periodical fullerene and graphene units were constructed using C, C, C, C and C fullerenes, followed by geometry optimization using Open Babel. All GCMC simulations of adsorption were performed in the RASPA. The adsorption isotherms of FPGNs for pure gases are comparatively examined, and their performances are discussed based on the pore structure and isosteric heat of adsorption. Then, the separation factors of FPGNs for equimolar binary mixtures of these gases are elucidated from the difference in the heat of adsorption and the adsorption selectivity.