Separation Science and Technology, Vol.50, No.3, 380-386, 2015
Extraction of Uranyl Ion Using 2-Thenoyltrifluoro Acetone (HTTA) in Room Temperature Ionic Liquids
The extraction of UO22+ ion was studied using six different solvent systems containing 2-thenoyltrifluoroacetone (HTTA) in room temperature ionic liquids such as [C(n)mim][X] (where, n = 4, 6, or 8 and X- = PF6- or NTf2-) from low to moderate pH solutions for the first time. The extraction kinetics studies indicated rather slow attainment of equilibrium which in some cases improved if the solutions were pre-equilibrated with the aqueous phase prior to the actual experiments. The D-U values were found to increase with increasing pH and leading to a plateau like profile at higher pH values. The D values were quite high as compared to that obtained with molecular diluents. The nature of the extracted species was ascertained by slope analysis method which suggested species of the type: UO2(TTA)(+)(IL), UO2(TTA)(2,IL), and UO2(TTA)(2)(HTTA)(IL) in different ionic liquid based solvents. Temperature variation studies on UO22+ ion extraction were also carried out and the thermodynamic parameters were calculated which indicated high endothermicity of the reactions with large positive entropy values.