Selective Separation of Lithium Chloride by Organogels Containing Strapped Calix[4]pyrroles

Hu Wang, Leighton O. Jones, Inhong Hwang, Marshall J. Allen, Daliao Tao, Vincent M. Lynch, Benny D. Freeman, Niveen M. Khashab, George C Schatz, Zachariah A. Page, Jonathan L. Sessler

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Reported herein are two functionalized crown ether strapped calix[4]pyrroles, H1 and H2. As inferred from competitive salt binding experiments carried out in nitrobenzene-d5 and acetonitrile-d3, these hosts capture LiCl selectively over four other test salts, viz. NaCl, KCl, MgCl2, and CaCl2. Support for the selectivity came from density functional theory (DFT) calculations carried out in a solvent continuum. These theoretical analyses revealed a higher innate affinity for LiCl in the case of H1, but a greater selectivity relative to NaCl in the case of H2, recapitulating that observed experimentally. Receptors H1 and H2 were outfitted with methacrylate handles and subject to copolymerization with acrylate monomers and cross-linkers to yield gels, G1 and G2, respectively. These two gels were found to adsorb lithium chloride preferentially from an acetonitrile solution containing a mixture of LiCl, NaCl, KCl, MgCl2, and CaCl2 and then release the lithium chloride in methanol. The gels could then be recycled for reuse in the selective adsorption of LiCl. As such, the present study highlights the use of solvent polarity switching to drive separations with potential applications in lithium purification and recycling.
Original languageEnglish (US)
JournalJournal of the American Chemical Society
StatePublished - Nov 23 2021

Bibliographical note

KAUST Repository Item: Exported on 2021-11-25
Acknowledged KAUST grant number(s): OSR-2019-CRG8-4032
Acknowledgements: J.L.S. and N.M.K. acknowledge support from the King Abdullah University of Science and Technology (KAUST; Grant OSR-2019-CRG8-4032). L.O.J. and G.C.S. were supported by the Center for the Sustainable Separation of Metals (CSSM) funded by the National Science Foundation (Grant No. CHE1925708). Initial support for the work in Austin was also provided by the CSSM. Subsequent support was provided by the Robert A. Welch Foundation (F-0018 and F-2007 to J.L.S. and Z.A.P., respectively). B.D.F.’s work in reviewing the manuscript was supported as part of the Center for Materials for Water and Energy Systems (M-WET), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award No. DE-SC0019272.

ASJC Scopus subject areas

  • Biochemistry
  • Colloid and Surface Chemistry
  • General Chemistry
  • Catalysis


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