Microporous carbon granules with narrow pore size distribution and rich oxygen functionalities for Xe/Kr separation

Abstract

The direct adsorptive separations of xenon (Xe) and krypton (Kr) using granular porous carbons remain challenging yet industrially important. Herein, we report microporous carbon granules with narrow pore size distributions and rich oxygen functionalities for efficient Xe/Kr separation. The optimized granular carbon (GBC-900) breaks the trade-off effect by showing high Xe uptake capacity (4.71 mmol g−1) and Xe/Kr selectivity (18.3) at 298 K and 1.0 bar. Notably, the synergistic effect of oxygen-functionalities and uniform micropores renders the ultrahigh Xe uptake of 2.78 mmol g−1 at 0.2 bar. Furthermore, density functional theory calculations disclose the strong affinity between oxygen groups and Xe atoms. Dynamic breakthrough experiments confirm the practical Xe/Kr separation feasibility even from humid and low-concentration Xe/Kr gas-mixtures.