DIRECT SPECTROSCOPIC SPECIATION OF SCHOEPITE-AQUEOUS PHASE-EQUILIBRIA

UV-Vis spectra of solutions in solid-aqueous phase equilibrium with UO 3 . 2H(2)O(s) and 0.03 kPa CO2 partial pressure are quantitatively ana lyzed by single component spectra of hydrolysis species UO22+(aq), (UO 2)(2)(OH)(2)(2+) and (UO2)(3)(OH)(5)(+). From the deconvoluted spectra , single species concentrations are obtained and interpreted by variou s statistical methods. Relationship of UV-Vis data to fluorescence spe ctroscopic analysis of the same system is discussed. Calculation of th ermodynamic quantities gave consistent results, both within experiment al data and with results from solubility studies and spectroscopic ana lysis from literature. A reinterpretation of some literature data is p roposed.