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Sustainable lithium extraction enabled by responsive metal-organic frameworks with ion-sieving adsorption effects.

Xu WuHuacheng ZhangXinyu ZhangQian GuanXiaocong TangHao WuMingbao FengHuanting WangRanwen Ou
Published in: Proceedings of the National Academy of Sciences of the United States of America (2024)
Metal-organic frameworks (MOFs) are superior ion adsorbents for selectively capturing toxic ions from water. Nevertheless, they have rarely been reported to have lithium selectivity over divalent cations due to the well-known flexibility of MOF framework and the similar physiochemical properties of Li + and Mg 2+ . Herein, we report an ion-sieving adsorption approach to design sunlight-regenerable lithium adsorbents by subnanoporous MOFs for efficient lithium extraction. By integrating the ion-sieving agent of MOFs with light-responsive adsorption sites of polyspiropyran (PSP), the ion-sieving adsorption behaviors of PSP-MOFs with 6.0, 8.5, and 10.0 Å windows are inversely proportional to their pore size. The synthesized PSP-UiO-66 with a narrowest window size of 6.0 Å shows high LiCl adsorption capacity up to 10.17 mmol g -1 and good Li + /Mg 2+ selectivity of 5.8 to 29 in synthetic brines with Mg/Li ratio of 1 to 0.1. It could be quickly regenerated by sunlight irradiation in 6 min with excellent cycling performance of 99% after five cycles. This work sheds light on designing selective adsorbents using responsive subnanoporous materials for environmentally friendly and energy-efficient ion separation and purification.
Keyphrases
  • metal organic framework
  • aqueous solution
  • solid state
  • cancer therapy
  • ion batteries
  • radiation therapy
  • liquid chromatography
  • radiation induced
  • recombinant human