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Fine-Tuning Window Apertures in ZIF-8/67 Frameworks by Metal Ions and Temperature for High-Efficiency Molecular Sieving of Xylenes.

Daniil M PolyukhovArtem S PoryvaevAleksandr S SukhikhSergey A GromilovMatvey V Fedin
Published in: ACS applied materials & interfaces (2021)
Separation of structurally similar components from their mixtures is one of the most promising applications of metal-organic frameworks (MOFs). A high efficiency of such molecular sieving requires fine tuning of the MOF structure. In this work, we investigate subtle metal- and temperature-induced changes in window dimensions of zeolitic imidazolate frameworks (ZIF-8(Zn) and ZIF-67(Co)) and apply such structural tuning for efficient separation of xylene isomers (p-, m-, and o-xylenes). The use of Co instead of Zn favorably modifies window geometry: it accelerates the diffusion of all components by a factor of 2-3 while maintaining closely the same separation efficiency as that of ZIF-8(Zn). Outstanding selectivity above 18:1 and faster isolation of demanded p-xylene from the ternary mixture using ZIF-67(Co) have been demonstrated at room temperature, opening new horizons for its energy-efficient xylene separation. More generally, our findings suggest the prospective ways to tune various MOFs for target liquid-state separations.
Keyphrases
  • high efficiency
  • metal organic framework
  • room temperature
  • liquid chromatography
  • ionic liquid
  • heavy metals
  • air pollution
  • mass spectrometry
  • single molecule
  • quantum dots
  • gold nanoparticles
  • risk assessment