It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for ...It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.展开更多
Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching e...Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching effect between the cavities of crown ethers and Li+,crown ethers can selectively adsorb Li^(+).Herein,1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 was synthesized and used to extract lithium from a Li^(+)/Na^(+)mixed solution.Density functional theory(DFT)was used to explore the properties of complexes with M062X.The results show that the interactions between crown ethers and metal ions are due to electrostatic attraction.Hydroxyl functional groups can synergistically extract Li^(+)/Na^(+)from solutions with the oxygen atom in the crown ether ring.The stability of the complex is also enhanced by van der Waals interactions between the butyrate acid root and crown ether.1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 has a stronger interaction with lithium butyrate than with sodium butyrate for most conformations.The adsorption selectivity for Li+is proportional to the number of ether oxygen atoms that interact with Li^(+).The Li^(+)extraction efficiency increases from 3.93%to 20.93%in lithium hydroxide solution with the presence of butyrate acid root.When the butyrate acid root is added to the mixed Li^(+)/Na^(+)solution,the Li^(+)extraction efficiency increases from 6.54%to 31.20%,while the Li^(+)/Na^(+)separation coefficient decreases from33.25 to 1.32.展开更多
基金supported by the National Natural Science Foundation of China(No.51604005,No.U1703130,and No.51574003)
文摘It is a challenge to recover lithium from the leaching solution of spent lithium-ion batteries,and crown ethers are potential extractants due to their selectivity to alkali metal ions.The theoretical calculations for the selectivity of crown ethers with different structures to Li ions in aqueous solutions were carried out based on the density functional theory.The calculated results of geometries,binding energies,and thermodynamic parameters show that 15C5 has the strongest selectivity to Li ions in the three crown ethers of 12C4,15C5,and 18C6.B15C5 has a smaller binding energy but more negative free energy than 15C5 when combined with Li^+,leading to that the lithium ions in aqueous solutions will combine with B15C5 rather than 15C5.The exchange reactions between B15C5 and hydrated Li^+,Co^2+,and Ni^2+were analyzed and the results show that B15C5 is more likely to capture Li^+from the hydrated ions in an aqueous solution containing Li^+,Co^2+,and Ni^2+.This study indicates that it is feasible to extract Li ions selectively using B15C5 as an extractant from the leaching solution of spent lithium-ion batteries.
基金financially supported by the National Natural Science Foundation of China(Nos.51704011,U1703130 and 51904003)。
文摘Lithium is critical for economic growth since it is the primary component of batteries.Na^(+)is one of the main impurity ions in solution during the separation and enrichment of Li^(+).According to the size-matching effect between the cavities of crown ethers and Li+,crown ethers can selectively adsorb Li^(+).Herein,1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 was synthesized and used to extract lithium from a Li^(+)/Na^(+)mixed solution.Density functional theory(DFT)was used to explore the properties of complexes with M062X.The results show that the interactions between crown ethers and metal ions are due to electrostatic attraction.Hydroxyl functional groups can synergistically extract Li^(+)/Na^(+)from solutions with the oxygen atom in the crown ether ring.The stability of the complex is also enhanced by van der Waals interactions between the butyrate acid root and crown ether.1,8-dihydroxyl-4,4,5,5-tetramethylbenzo-14-crown-4 has a stronger interaction with lithium butyrate than with sodium butyrate for most conformations.The adsorption selectivity for Li+is proportional to the number of ether oxygen atoms that interact with Li^(+).The Li^(+)extraction efficiency increases from 3.93%to 20.93%in lithium hydroxide solution with the presence of butyrate acid root.When the butyrate acid root is added to the mixed Li^(+)/Na^(+)solution,the Li^(+)extraction efficiency increases from 6.54%to 31.20%,while the Li^(+)/Na^(+)separation coefficient decreases from33.25 to 1.32.
