Comparison Of The Uranium(?) Extraction In Ionic Liquids And Traditional Solvents By HOX

In this work, the liquid-liquid extraction of Uranium(VI) by 8-hydroxyquinoline( HOX) in C4 mim PF(ionic liquids) and CH Cl(traditional solvents) was investigated, and the extraction behaviors and mechanisms in UO /HOX/ C4 mim PF and UO /HOX/CH Cl systems were compared. The effect of various parameters in UO /HOX/ C4 mim PF and UO /HOX/CH Cl systems mainly studied:(1) The extraction equilibrium time in two systems;(2) The effect of HOX concentration in two systems;(3) The effect of acid and salt;(4) Stripping;(5)The study on extraction mechanism of extracting Uranium(VI) by 8-hydroxyquinoline in two systems;(6) The extraction complexes characterization. The results showed that:(1)It needs 30 seconds and 7 minutes for UO /HOX/CH Cl and UO /HOX/C4 mim PF systems to realize extraction equilibrium individually. So, to achieve extraction equilibrium in both systems, the experiment time should be set as 10 minutes.(2)The extraction efficiency and distribution ratio of UO22+ from aqueous phase to ionic liquids phase heavily relying on the concentration of HOX in UO /HOX/C4 mim PF systems. The extraction efficiency and distribution ratio of 1 mmol/L uranyl extracting by 10 mmol/L 8-hydroxyquinoline can reach 91% and 21 in UO /HOX/ C4 mim PF systems, 55% and 2 in UO /HOX/CH Cl systems. Thus, the extraction efficiency can be greatly improved by applying ILs instead of traditional solvents as diluents.(3) The effect of HNO ?Na NO and C4 mim NO on uranyl extraction efficiency in different concentration of HNO ? Na NO and C4 mim NO. The extraction efficiency for Uranyl decreases strongly with increasing the concentration of HNO in UO /HOX/ C4 mim PF and UO /HOX/CH Cl systems. The addition of Na NO3 reveals less of effect on the extraction efficiencies of Uranyl in two systems. The extraction efficiency of uranyl significantly decreased with increasing the concentration of C4 mim NO in UO /HOX/ C4 mim PF, but less effect on in UO /HOX/CH Cl. The results mean that H+ can reduce the extraction efficiency of the two systems. Na and NO has no effect on the two systems. But increasing the concentration of C4 mim could reduce the extraction efficiency in UO /HOX/ C4 mim PF, and has no effect on UO /HOX/CH Cl system.(4) According to the stripping results of the two systems, nitric acid can effectively use the uranyl ion in the ionic liquid phase and organic phase extraction. And stripping efficiency of uranyl can reach 90% and 75% in the ionic liquid and organic phase systems.(5) The stoichiometry of the HOX to the UO are all 3:1 in two systems by the slope analysis method. The extractable complex may be without NO in both extraction systems. PF can participate in extraction in the extraction of compound ligand and the coordination number is 1, therefore the extraction complex is identified as UO HOX OX PF in the UO /HOX/ C4 mim PF system, and as UO OX HOX in the UO /HOX/CH Cl system. It also showed that the extraction mechanisms were different in the two systems.(6)In this paper, the extraction complex of the two systems adopted different characterization methods, the extraction complex of the UO /HOX/ C4 mim PF system were characterized by infrared spectroscopy, the characterization results showed in 922 cm-1 has the interaction between HOX and UO peak. In UO /HOX/CH Cl system adopted the approach of growing crystal of structural chemistry, the result shows that the extraction complex is as UO OX HOX. The structural chemistry was successfully applied to the characterization of extraction complex in this paper.