Optimizing Pore Size and Polarity in Halogen-Functionalized Metal–Organic Frameworks for Efficient Xenon/Krypton Separation: A Synergistic Strategy

High-purity xenon (Xe) is crucial
in semiconductor manufacturing
and medical imaging, but trace krypton (Kr) in Xe poses a significant
challenge in separation due to their highly similar properties. Traditional
gas separation methods are ineffective for Xe/Kr, necessitating innovative
adsorbent materials. This study proposes an effective strategy using
halogen-functionalized ligands to adjust the pore size and polarity
in metal–organic framework (MOF) materials, achieving efficient
Xe/Kr separation. A series of MOFs (LIFM-DMOF-X1, X = F,
Cl, Br, I) were designed to simultaneously control pore size and wall
polarity. Experimental results show that LIFM-DMOF-Cl1 and
LIFM-DMOF-Br1 exhibit excellent adsorption performance
and selectivity for Xe/Kr. Theoretical calculations confirm stronger
Xe interactions with MOF C–H groups and halogen atoms, validating
the structure–property relationship. This approach provides
a synergistic strategy for developing particular gas separation materials
for Xe/Kr.