One-Step CO₂/Xe/Kr Purification from Used Nuclear Fuel Reprocessing Off-Gas via Gas Preparative Chromatography

Capture and purification of CO₂, Xe, and Kr from used nuclear fuel (UNF) reprocessing off-gas is of environmental and industrial importance. However, designing adsorbents that simultaneously exhibit high capacity, selectivity, and radiation resistance remains a significant challenge. Herein, three MOFs (HUKST-1, CALF-20, and SIFISIX-3-Ni) possessing distinct pore environments for CO₂/Xe/Kr adsorption separation from UNF reprocessing off-gas are evaluated. CALF-20 demonstrates exceptional performance due to its pore environment, which facilitates differential recognition and polarization of the target gases-a key factor in achieving selective gas preparative chromatography separation. Adsorption isotherms, breakthrough curves, and chromatographic profiles reveal that CALF-20 offers an excellent capture and separation performance for CO₂, Xe, and Kr under dilute conditions. Furthermore, gamma-ray irradiation experiments confirme the high radiation stability of CALF-20, indicating its strong potential for practical application. This work establishes CALF-20 as a benchmark adsorbent for one-step CO₂/Xe/Kr purification from UNF reprocessing off-gas and highlights the promise of rational pore environment control in MOFs to engineer tailored adsorbents for specialized separations.