The extraction and separation of cerium(IV) and yttrium(III) from citric acid solution using Di-2-ethylhexyl phosphoric acid, D2EHPA, in kerosene was investigated. The effects of the different parameters on the extraction process, including the shaking time, extractant concentration, phase ratio, acid concentration as well as, temperature, were separately investigated to achieve the maximum possible separation between Ce(IV) and Y(III). The extraction constant was modeled based on the most predominant citrate cationic species at pH 4.0. The stoichiometry of the extracted species was found to be [Ce(H₂Cit)₂·2A(HA)] and [Y(H₂Cit)·2A(HA)], (where HA denotes D2EHPA), based on the slope analysis method applied on the obtained results. The mean conditional extraction constants values K_C.ex were found to be 4.15 × 10² ± 0.05 and 5.36 ± 0.28 × 10³ for Ce(IV) and Y(III), respectively. The thermodynamic functions associated with the extraction reaction were evaluated and discussed. It was found that the extraction process is spontaneous and exothermic for both metal ions. Possible separation of Y(III) from Ce(IV) was given in terms of the separation factors at different extraction conditions.

中文翻译：

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在煤油中使用D2EHPA溶剂萃取从柠檬酸盐介质中分离铈（IV）和钇（III）

研究了在煤油中使用二-2-乙基己基磷酸D2EHPA从柠檬酸溶液中萃取和分离铈（IV）和钇（III）。分别研究了不同参数对萃取过程的影响，包括振荡时间，萃取剂浓度，相比，酸浓度以及温度，以实现Ce（IV）和Y（III）之间的最大可能分离。基于pH 4.0下最主要的柠檬酸盐阳离子种类对提取常数进行建模。发现提取物的化学计量为[Ce（H ₂ Cit）₂ ·2A（HA）]和[Y（H ₂Cit）·2A（HA）]，（其中HA表示D2EHPA），基于对所得结果应用的斜率分析方法。对于Ce（IV）和Y（III），平均条件提取常数值K _C.ex分别为4.15×10 ²  ±0.05和5.36±0.28×10 ³。评估和讨论了与萃取反应有关的热力学函数。已发现两种金属离子的萃取过程是自发的且放热的。根据在不同萃取条件下的分离因子，给出了可能的Y（III）与Ce（IV）的分离。