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 mu g U(VI)/mL concentration interval, with molar absorbtivity epsilon(max) = 4.3 x 10(5) mol(-1) cm(2) and Sandell sensitivity = 0.0526 mu g 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 center dot(L)(2)center dot(S)(4)], is characterized by the following parameters: metal/ligand combination ratio: M/L = 1/2, stability constant beta = 2.06 x 10(6), distribution coefficient D = 66.56 (V-org = V-aq), percentage extraction E% = 98.52, and recovery factor, R%, ranging between 99.48 and 99.85%.