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Li-6 and Li-7 are strategic resources. Because Li+ ions have no outermost electrons and the radii of Li-6 and Li-7 differ by only one neutron, the separation of the naturally stable isotopes of Li, especially by solvent extraction, is recognized as a difficult problem worldwide. Therefore, in this paper, an advanced beta-diketone-driven deep eutectic solvent (DES) extraction system containing 2-thenoyltrifluoroacetone (HTTA) and tri-n-octyl phosphine oxide (TOPO) is introduced to the extraction and separation of Li-6(+) and Li-7(+) ions. Compared with those of reported HTTA extraction systems and crown ether extraction systems, the separation coefficient (beta 7(Li)/6(Li)) of the beta-diketone-driven DES extraction system can reach the best value of 1.068, which is now the highest known beta-value reported in the extraction system. From the intramolecular hydrogen bond of HTTA to the intermolecular hydrogen bond of DES, the bond energy increases by 47.8%. Because the active site of the proton in DES provides a higher energy barrier for the separation of Li-7, the beta 7(Li)/6(Li) is significantly increased. The extractions were characterized by spectrum, using H-1 nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The mechanism was determined on the basis of the reaction kinetics and density functional theory (DFT). The DES extractant shows excellent cycle performance with regard to stripping and reusability. In conclusion, the highly efficient, economical, and stable beta-diketone-driven DES extraction system can be used for the separation of naturally stable Li isotopes, which provides good industrial application prospects.
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SEPARATIONS
ISSN: 2297-8739
Year: 2023
Issue: 2
Volume: 10
2 . 5
JCR@2023
2 . 5 0 0
JCR@2023
ESI Discipline: CHEMISTRY;
ESI HC Threshold:39
JCR Journal Grade:3
CAS Journal Grade:4
Cited Count:
WoS CC Cited Count: 0
SCOPUS Cited Count:
ESI Highly Cited Papers on the List: 0 Unfold All
WanFang Cited Count:
Chinese Cited Count:
30 Days PV: 3
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