Extraction of uranium from carbonate solution using synthesized Schiff base and its application for spectrophotometric determination

摘要

A new Schiff base extractant, O-[1-(2-pyridylimino) ethyl] phenol (PEPh), was synthesized to separate and pre-concentrate U(VI) ions from carbonate solution prior to its spectrophotometric determination. Various instrumental techniques such as elemental analysis, FTIR, and ~1H NMR analysis were employed for full characterization of the synthetic extractant. Analyses of the traditional log10 D versus log10 extractant concentrations and versus pH reveal that the uranium ions were extracted as a complex that is characterized by having a ligand: metal ratio of 2:1 and one ionizable hydrogen ion. The operating extraction and stripping conditions of U(VI) in the present study have been experimentally optimized. From the extractant effects, 0.05 M synthesized PEPh was found suitable for the separation of U(VI). The thermodynamic study indicates that the extraction of uranium(VI) from carbonate medium is an exothermic process (ΔH = - 17.08 kJ mol~(-1)). The construction of extraction and stripping isotherm showed that three theoretical stages would be indicated for countercurrent treatment. The tolerance limits for several metal ions on synthesized Schiff base extractant were calculated and gave a high tolerance limit. The optimum parameters of solvent extraction were applied for the spectrophotometric determination of U(VI) in different carboniferous rock using Arsenazo III with accurate results.