Perfect confinement of crown ethers in MOF membrane for complete dehydration and fast transport of monovalent ions.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 38718127.
- Also identified by DOI 10.1126/sciadv.adn0944 and PMC identifier 11078184.
- Licence recorded as CC BY-NC.
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Abstract
Fast transport of monovalent ions is imperative in selective monovalent ion separation based on membranes. Here, we report the in situ growth of crown ether@UiO-66 membranes at a mild condition, where dibenzo-18-crown-6 (DB18C6) or dibenzo-15-crown-5 is perfectly confined in the UiO-66 cavity. Crown ether@UiO-66 membranes exhibit enhanced monovalent ion transport rates and mono-/divalent ion selectivity, due to the combination of size sieving and interaction screening effects toward the complete monovalent ion dehydration. Specifically, the DB18C6@UiO-66 membrane shows a permeation rate (e.g., K<sup>+</sup>) of 1.2 mol per square meter per hour and a mono-/divalent ion selectivity (e.g., K<sup>+</sup>/Mg<sup>2+</sup>) of 57. Theoretical calculations and simulations illustrate that, presumably, ions are completely dehydrated while transporting through the DB18C6@UiO-66 cavity with a lower energy barrier than that of the UiO-66 cavity. This work provides a strategy to develop efficient ion separation membranes via integrating size sieving and interaction screening and to illuminate the effect of ion dehydration on fast ion transport.