双功能离子液体在氯化物介质中萃取分离Eu^(3+)的应用

Application of bifunctional ionic liquids for extraction and separation of Eu^(3+) from chloride medium

研究使用双功能离子液体萃取剂(Bif-ILEs)三辛基甲基氯化铵二(2-乙基己基)磷酸酯([A336][D2EHP])和十四烷基三己基氯化膦二(2-乙基己基)磷酸酯([P_(66614)][D2EHP])、以煤油作稀释剂从氯化物介质中萃取Eu^(3+)的过程,以开发环境友好的铕萃取工艺。通过改变关键工艺参数,研究Eu^(3+)的萃取行为。萃取研究表明,铵基离子液体[A336][D2EHP]对Eu^(3+)的萃取效率优于膦基离子液体[P_(66614)][D2EHP]。例如,使用0.05 mol/L[A336][D2EHP]可以定量萃取Eu^(3+),而需要0.1 mol/L的[P_(66614)][D2EHP]才能达到相同的Eu^(3+)萃取率。对于[A336][D2EHP],铕的萃取为吸热过程。反萃实验表明,使用20%HNO_(3)(体积分数)可以将100%的Eu^(3+)从两种负载的离子液体中反萃下来。在pH值3.2时,分离因子(bY/Eu)最高,达到653.59;在相同pH值下,Eu^(3+)对La^(3+)的分离因子为30.6。采用0.2 mol/L[A336][D2EHP]、相比O/A=1:1和1:2的两级错流萃取,可从废灯管荧光粉浸出液中回收99.98%的Eu和99.99%的Y。

The extraction of Eu^(3+)from chloride medium using bifunctional ionic liquid extractants(Bif-ILEs)tri-n-octylmethyl ammonium bis(2-ethyl hexyl)phosphate([A336][D2EHP])and trihexyltetradecyl phosphonium bis(2-ethylhexyl)phosphate([P_(66614)][D2EHP])in kerosene was studied to develop environmentally friendly extraction process.The extraction behavior of Eu^(3+)was examined by varying key process parameters.The extraction behavior indicates that ammonium-based ionic liquid[A336][D2EHP]shows better extraction efficiency of Eu^(3+)than that of phosphonium-based ionic liquid[P_(66614)][D2EHP].Quantitative extraction of Eu^(3+)is obtained with 0.05 mol/L[A336][D2EHP],whereas,0.1 mol/L of[P_(66614)][D2EHP]is required to achieve the same extraction rate of Eu^(3+).The extraction process is endothermic with respect to[A336][D2EHP].Stripping experiments indicate that 100%of Eu^(3+)can be back extracted from both the loaded ionic liquids using 20 vol.%HNO_(3).The highest separation factor(βY/Eu)of 653.59 is reported at pH of 3.2,and the separation factor of Eu^(3+)over La^(3+)is 30.6 at the same pH.From the leach liquors of waste tube light powder,99.98%of Eu and 99.99%Y are recovered using 0.2 mol/L[A336][D2EHP]in 2-stage cross current extraction with aqueous to organcic ratio(O/A)of 1:1 and 1:2.