四乙基双三嗪吡啶与二酰胺荚醚在硝酸介质中对Am(Ⅲ)/Eu(Ⅲ)的协同萃取

Synergistic Extraction of Am(Ⅲ)and Eu(Ⅲ)by Mixture of 2,6-Bis(5,6-Diethyl-1,2,4-Triazin-3-yl)Pyridine and Diglycolamides in Nitric Acid Media

以四乙基双三嗪吡啶(C2-BTP)和四种不同链长的N,N,N′,N′-四烷基-3-氧-戊二酰胺(酰胺荚醚:DGA)作为萃取剂、1,2-二氯乙烷作为稀释剂,在硝酸体系中研究了对Am(Ⅲ)和Eu(Ⅲ)的协同萃取行为。结果表明,长链DGA与C2-BTP具有良好的协萃效应,在水相酸度为1.0 mol/L、盐析剂浓度为1.0 mol/L时,C2-BTP与六个碳链DGA(C6-DGA)的混合萃取剂摩尔比为3∶1时,Am(Ⅲ)和Eu(Ⅲ)的分配比(D)比单独使用C2-BTP提高一倍以上,Am(Ⅲ)与Eu(Ⅲ)的分离因子(SF)最高值约为21。利用斜率法分别确定了各个DGA作为单一萃取剂萃取Am(Ⅲ)和Eu(Ⅲ)的平均配位数约为1.5,表明氯代溶剂可能与DGA的配位氧原子发生了相互作用,影响了DGA对Am(Ⅲ)和Eu(Ⅲ)的配位性能。

In the present paper, the synergistic extraction characteristics o{ 2,6-his（5,6- diethyl- 1,2,4-triazin-3-yl） pyridine （C2-BTP） and diglycolamides （DGA） in 1,2-diehloroeth- ane, for the separation of Am（Ⅲ） and Eu（Ⅲ） from nitric acid media were studied. The results indicate that DGA with long alkyl chains increases the ability of synergistic extraction with C2-BTP. The distribution ratio（D） values with mixed extractants are more than twice that with C2-BTP alone, when the molar ratio of C2-BTP to C6-DGA is3 ： 1 in 1.0 mol/L HNO3 and 1.0 mol/L NaNO3. The highest separation factor（SF） value of Am（Ⅲ） over Eu（Ⅲ） is around 21 under given conditions. Slope analyses indicate that the average coordi- nation numbers of Am（ Ⅲ ） as well as Eu（Ⅲ ） extracted with DGA alone are determined to be around 1.5, indicating that the donor oxygen of diglycolamide probably interacts with the polar halogenated diluents, which affects the complexing ability for Am（Ⅲ） and Eu（ Ⅲ ）.