Department of Basic Sciences, Zarqa University College, Al-Balqa Applied University, Jordan.
Department of Chemistry, Faculty of Science, The Hashemite University, P. O. Box 330127, Zarqa 13133, Jordan.
J Colloid Interface Sci. 2021 Apr;587:229-239. doi: 10.1016/j.jcis.2020.12.029. Epub 2020 Dec 16.
Alkyl phosphates were extensively used in liquid-liquid extraction of lanthanides and actinides, but to a lesser extent for alkali and alkaline earth metals. The high amount of alkyl phosphate, which is usually used in the organic layer (>40 wt%), is not favoured due to its corrosive effect and toxicity. In the present work, diluted chloroform solutions (20.0 mM) of tri-n-butyl phosphate (TBP), tris(2-ethylhexyl) phosphates (TRIS) and bis(2-ethylhexyl) phosphate (BIS) were investigated for their extraction of Li, Na, K, Mg and Ca ions. The extraction experiments were conducted on 7.0 M HNO aqueous solutions containing 60.0 mM of metal ions in binary (Li and Mg), ternary (Li, Na and K) and quinary (Li, Na, K, Mg and Ca) mixtures. The Li selectivity over Mg was very high in the binary system. Remarkably, increasing HNO concentration in the aqueous layer had opposing effect on the extraction of Li (positive) and Mg (negative). However, the selectivity for Li became less dramatic in the case of ternary and quinary system, though the selectivity varied with initial metal concentrations. The amounts of water and NO transferred into the organic layer demonstrated their synergistic effect on extracting metal ions. In the ternary and quinary systems, the total concentrations of metal ions in the organic layer (ranged from 49 to 85 mM) were higher than the concentration of ligand in the organic layer (20.0 mM), suggesting that metal ions may be extracted into water/ligand/NO aggregates in the organic layer. TBP, TRIS and BIS do not have significant difference in their extraction behaviour. The FTIR results indicated formation of P-OM/M in the solid TBP/metal complex.
烷基磷酸酯被广泛用于镧系和锕系元素的液-液萃取，但用于碱金属和碱土金属的萃取则较少。由于烷基磷酸酯的腐蚀性和毒性，通常在有机相中使用较高浓度的烷基磷酸酯（>40wt%）是不被推荐的。在本工作中，研究了三正丁基磷酸酯（TBP）、三（2-乙基己基）磷酸酯（TRIS）和双（2-乙基己基）磷酸酯（BIS）在稀释的氯仿溶液（20.0mM）中对 Li、Na、K、Mg 和 Ca 离子的萃取行为。萃取实验在含有 60.0mM 金属离子的 7.0M HNO3水溶液中进行，金属离子包括二元（Li 和 Mg）、三元（Li、Na 和 K）和五元（Li、Na、K、Mg 和 Ca）混合物。在二元体系中，Li 对 Mg 的选择性非常高。值得注意的是，水相中 HNO3浓度的增加对 Li（正）和 Mg（负）的萃取有相反的影响。然而，在三元和五元体系中，Li 的选择性变得不那么显著，尽管选择性随初始金属浓度而变化。进入有机相的水和 NO 的量表明它们对金属离子萃取具有协同作用。在三元和五元体系中，有机相中金属离子的总浓度（范围为 49 至 85mM）高于有机相中配体的浓度（20.0mM），这表明金属离子可能被萃取到有机相中的水/配体/NO 聚集体中。TBP、TRIS 和 BIS 在萃取行为上没有显著差异。FTIR 结果表明在固体 TBP/金属配合物中形成了 P-OM/M。
