双功能离子液体[A336][P507]在盐酸和硝酸介质中对Sc(Ⅲ)的萃取

Extraction of Sc( Ⅲ) Using a Bifunctional Ionic Liquid [A336][P507]

利用双功能离子液体萃取剂三辛基甲基氯化铵2-乙基己基磷酸2-乙基己基酯盐([A336][P507])在HCl和HNO3介质中对Sc(Ⅲ)的萃取和分离。研究表明,萃取剂在低酸度条件下,对Sc(Ⅲ)有较好的萃取能力;但是当水相酸度从0.5 mol/L增加到4 mol/L,Sc(Ⅲ)的萃取率有较大程度的下降。并且讨论了在HCl介质和HNO3介质中,[A336][P507]萃取Sc(Ⅲ)的机理,由于Sc(Ⅲ)的半径最小,而且在萃取过程中存在PO与P—O的竞争作用,使得其萃合物结构与轻稀土不同。水相中加入盐析剂Na Cl或Na NO3对Sc(Ⅲ)的萃取有一定的促进作用;萃取过程的热力学参数的结果表明,萃取反应是放热反应。还研究了混合稀土中Sc(Ⅲ)和其它稀土离子的分离,在较低酸度的条件下萃取剂[A336][P507]对其它稀土离子的萃取可以忽略不计,因此该萃取体系对Sc(Ⅲ)和其它稀土离子有较好的分离效果,显示了本研究潜在的应用价值。

Extraction of Sc （Ⅲ ） from HNO3 medium and HC1 medium using a bifunctional ionic liquid extractant [A336 [P507] was investigated. The results show that the extractability of Sc （Ⅲ） by [ A336 ] [ P507 ] is high at low acidity. The extraction efficiency of Sc（ Ⅲ） decreases when the aqueous phase acidity increases from 0. 5 mol/L to 4 moL/L. The extraction mechanism was investigated. The extracted complex of Se （ Ⅲ ） is different from light REs due to the smaller radius of Sc （Ⅲ ） and the competitive effect of P--O and P--O. The extraction efficiency of Sc （Ⅲ ） is enhanced with the increase concentration of NaC1 or NaNO3 in the aqueous phase. Thermodynamic functions of the extraction reaction demonstrate that the extraction of Se （Ⅲ） is an exothermic process. Extraction of other rare earth ions at low acidity by the extractant is negligible suggesting that [ A336 ] [ P507 ] has potential in industrial applications of Sc （ Ⅲ ） extraction and separation over other rare earth ions.