二环己基-18-冠-6对锶的萃取

Extraction of Strontium With Dicyclohexyl-18-Crown-6

为了解二环己基-18-冠-6(DCH18C6)在酸性介质中对锶的萃取行为,考察了DCH18C6的浓度、不同酸介质、不同稀释剂、硝酸浓度对锶分配比的影响。结果表明,该萃取体系在硝酸介质中能够有效的萃取锶,当DCH18C6浓度为0.1 mol/L时,萃取率高于92%,用去离子水反萃时,反萃率可达100%。采用双对数斜率法确定了DCH18C6萃取锶的萃合物组成,当c(DCH18C6)<8 mmol/L时,DCH18C6同锶萃合物的组成为1:2应占主要份额。当c(DCH18C6)≥8 mmol/L时,此时DCH18C6同锶萃合物的组成为1:1应占主要份额。

The extraction of strontium with dicyclohexyl- 18-crown-6 （DCH 18C6） from acidic so- lution was studied. The influence of the concentration of DCH18C6, different acids, different diluents, and the concentration of nitric acid was examined. The results show that Sr^2＋ can be efficiently extracted by DCH18C6 dissolved in 1,1,2,2-tetrachloroethane from a nitric acid solution. The extraction percentage of Sr^2＋ by 0.1 mol/L DHC18C6 is found to be higher than 92%. The extracted Sr^2＋ can be easily stripped with deionized water. Nearly 100% recovery of Sr^2＋ is achieved by three times of such stripping. The stoichiometric ratio of Sr^2＋ to DCH18C6 in the extracted complexes was studied by plotting the logarithm of distribution ratio of Sr^2＋ against the logarithm of the concentration of DCH18C6 in organic phase. From the slopes of the obtained curve it can be deduced that the stoichiometric ratio of Sr^2＋ to DCH18C6 of the major extracted species is 2 ： 1 when c （DCH18C6）〈 8 mmol/L, and 1 ： 1 when c（DCH18C6） ≥8 mmol/L.