Role of organic diluent on actinide ion extraction using a both-side diglycolamide-functionalised calix[4]arene

Extraction of Am³⁺ was done using a both-side diglycolamide-functionalised calix[4]arene with eight DGA pendent arms (Calix8DGA) in several organic diluents. The observed extraction trend was nitrobenzene>n-dodecane (with 5% isodecanol as phase modifier) > phenyltrifluoromethylsulphone (PTMS) > hexone∼2- nitrophenyloctylether∼1-octanol>chloroform at 0.1 M HNO₃, which changed at higher acidities (3 M) showing crossovers between the nitrobenzene-n-dodecane and the PTMS-hexone pairs. The Am³⁺ extraction as a function of the nitric acid concentration showed increasing D values with increasing acidities. The extraction behaviour was correlated with various parameters such as Schmidt's diluent parameter, dielectric constant and so on. The nature of the extracted species was ascertained in various diluents by the slope analysis method, while temperature variation studies were carried out to determine the thermodynamic parameters, which in turn explain the extraction mechanism. The separation behaviour of Am³⁺ with respect to UO₂²⁺ and Sr²⁺ was also investigated in these diluents.