Understanding the Recovery of Rare-Earth Elements by Ammonium Salts
Understanding the Recovery of Rare-Earth Elements by Ammonium Salts
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DOI：
10.3390/met8060465
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发表时间：
2018-06-01
期刊：
影响因子：
2.9
通讯作者：
Love, Jason B.
中科院分区：
文献类型：
--
作者：
Hunter, Jamie P.;Dolezalova, Sara;Love, Jason B.
虽然离子液体（IL）从水溶液中回收稀土元素（RE）已经有了很好的记录，但在有机相中形成的金属化合物仍然很难表征。使用光谱，分析和计算技术，我们提供了详细的化学分析的有机相中形成的化合物在溶剂萃取稀土[（正辛基）（3）NMe][NO3]（IL）。这些实验表明，稀土回收使用IL是一个快速的过程，IL是高度耐用的。Karl-Fischer测量表明作用模式不太可能是胶束，而通过负离子电喷雾电离质谱法观察到通式REE（NO3）（4）（IL）（2）（-）的离子。此外，变温La-139核磁共振光谱表明存在多个低对称性硝酸根物种。经典的分子动力学模拟显示聚集的多个离子液体周围的微水化的镧3+阳离子与四个硝酸盐完成内部的协调领域。这种增加的理解现在被用来开发更强和更有选择性的，功能化的离子液体用于REE回收。
While the recovery of rare earth elements (REEs) from aqueous solution by ionic liquids (ILs) has been well documented, the metal compounds that are formed in the organic phase remain poorly characterized. Using spectroscopic, analytical, and computational techniques, we provide detailed chemical analysis of the compounds formed in the organic phase during the solvent extraction of REEs by [(n-octyl)(3)NMe][NO3] (IL). These experiments show that REE recovery using IL is a rapid process and that IL is highly durable. Karl-Fischer measurements signify that the mode of action is unlikely to be micellar, while ions of the general formula REE(NO3)(4)(IL)(2)(-) are seen by negative ion electrospray ionization mass spectrometry. Additionally, variable temperature La-139 nuclear magnetic resonance spectroscopy suggests the presence of multiple, low symmetry nitrato species. Classical molecular dynamics simulations show aggregation of multiple ILs around a microhydrated La3+ cation with four nitrates completing the inner coordination sphere. This increased understanding is now being exploited to develop stronger and more selective, functionalized ILs for REE recovery.