(DdO)2DGA萃取Nd(Ⅲ)形成三相的研究

N,N′-二辛基-N,N′-二(十二烷基)-3-氧戊二酰胺（(DdO)₂DGA）是一种用于提取高放废液中三价锕系、镧系元素的不对称酰胺荚醚萃取剂，为确定其在萃取时的三相行为，本文以镧系元素中的代表性元素Nd为研究对象，考察酸度、温度、共存离子浓度对(DdO)₂DGA-正十二烷体系萃取Nd(Ⅲ)的极限有机相浓度（LOC）的影响，并采用红外光谱、紫外-可见吸收光谱、荧光光谱研究了三相出现前后(DdO)₂DGA-Nd(Ⅲ)萃合物结构的变化。结果表明，降低酸度、升高温度、降低共存离子浓度，Nd(Ⅲ)的LOC增加，但三相出现前后，萃合物结构没有改变，三相的形成是由于萃合物聚集形态改变所致。

Third Phase Formation in Extraction of Nd(Ⅲ) by (DdO)2DGA

N,N′-di-octyl-N,N′-di-dodecyl-3-oxapentane-1,5-diamide ((DdO)₂DGA) is a new unsymmetrical diglycolamide extractant for the separation of trivalent actinides and lanthanides from high level liquid waste. In this paper, the representative element Nd in lanthanides was taken as the research object to study the third phase formation behavior of Nd(Ⅲ) in (DdO)₂DGA, the influence of aqueous phase acidity, temperature and co-existing metal ion concentration on the limiting organic concentration (LOC) of Nd(Ⅲ) in (DdO)₂DGA/n-dodecane solution was investigated. The structural variation of (DdO)₂DGA-Nd(Ⅲ) complex formed in the organic phase before and after third phase formation was also studied by infrared spectra, UV-vis spectra and fluorescence spectra. The results show that LOC of Nd(Ⅲ) increases with temperature, and decreases with increase of aqueous acidity and co-existing metal ion concentration. However, the structure of (DdO)₂DGA-Nd(Ⅲ) complex is not varied before and after third phase formation, and the reason for third phase formation is the variation of aggregation behavior of extracted complexes.