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.