Résumé
Xenon (Xe) and krypton (Kr) have a variety of medical, industrial, and environmental applications, but their separation is difficult due to their chemical inertness and similar physical properties. This study presents a dual-functional modulation strategy for designing halogen-decorated pillar-layered MOFs (LIFM-DMOF-X2, X = F, Cl, Br) to improve the efficiency of Xe/Kr separation. The incorporation of halogenated terephthalate linkers (BDC-X2) and DABCO pillars enabled the frameworks to synergistically control the pore geometry and surface polarity via the steric and electronic effects of the halogens. LIFM-DMOF-Cl2 exhibited optimal performance with a Xe uptake of 3.58 mmol g−1 (298 K, 1.0 bar) due to its balance between pore size (6.14 Å) and high surface area (1259.8 m2 g−1). Dynamic breakthrough experiments confirmed the practical efficacy of this MOF, which showed a Xe retention time of up to 21 min/g and reusability for five cycles. GCMC simulations revealed multidimensional Xe-binding sites, including halogen bonds and π-interactions, with brominated variants showing exceptional polarization effects (Qst = 20.77 kJ mol−1). This work demonstrates the promise of halogen engineering in MOFs for nuclear off-gas treatment and noble gas capture.
•Innovative Xe/Kr Separation Strategy: Developed halogen-functionalized MOFs (LIFM-DMOF-X2, X = F, Cl, Br) via terephthalic acid substitution to optimize pore size/polarity for enhanced Xe adsorption/selectivity.•Adsorption performance: LIFM-DMOF-Cl2 achieved 3.58 mmol g−1 Xe uptake at 298 K/1.0 bar, showing outstanding Xe/Kr selectivity in static (IAST) and dynamic tests.•GCMC Validation: GCMC simulations revealed multidimensional Xe-binding sites, with brominated variants showing exceptional polarization effects.•Breakthrough Performance: Separated Xe from simulated nuclear off-gas (400 ppm Xe/40 ppm Kr) and maintained performance over 5 cycles with excellent recyclability.