Interaction of uranyl with acetate in aqueous solutions at variable temperatures

Increasing activities in the environmental management of nuclear wastes incite significant interest in the study of the interaction of actinides with organic matter in aqueous solution, especially at elevated temperature. The system U(VI)-acetic acid is studied in aqueous solutions at pH 2 in the temperature range from 15 °C to 55 °C by affinity capillary electrophoresis (ACE). The formation of two complex species UO2CH3COO+ and UO2(CH3COO)2 is observed. Thermodynamic parameters (the molar Gibbs energy of reaction (ΔrGm), the molar enthalpy of reaction (ΔrHm) and the molar entropy of reaction (ΔrSm)) are determined at fixed ionic strength of 0.05 mol · L−1 (NaClO4-HClO4) and calculated at 0 ionic strength with extended Debye-Hückel equation for the activity coefficients. Obtained results are compared with literature data.