Separation through liquid–liquid extraction and spectrophotometric determination of U(VI) with the ortho-aminophenol reagent

The extractive properties of the ortho-aminophenol reagent upon U(VI) were investigated in two solvents: 4-chlor-acetophenone and acetylacetone, in a water-organic solvent system. The method here proposed is based on the complexation reaction of the uranyl ion, UO22+, with ortho-aminophenol dissolved in 4-chlor-acetophenone, at room temperature, over a pH interval = 4–6, followed by spectro-photometry of the organic phase, involving measuring of absorbancy at 569.6 nm. The Beer law is valid over the 1–12 μg U(VI)/mL concentration interval, with molar absorbtivity εmax = 4.3 × 105 mol−1 cm2 and Sandell sensitivity = 0.0526 μg cm−2. The structure, stability and solubility of the formed complex was studied by UV–VIS and IR spectrometry, diffractometry and scanning electron microscopy. The mixed complex formed between the uranyl ion and the ortho-aminophenol dissolved in 4-chlor-acetophenone, [UO2.(L)2.(S)4], is characterized by the following parameters: metal/ligand combination ratio: M/L = 1/2, stability constant β = 2.06 × 106, distribution coefficient D = 66.56 (Vorg = Vaq), percentage extraction E% = 98.52, and recovery factor, R%, ranging between 99.48 and 99.85%.