The solubility, dissolution, and degradation of the bismuthate anion were studied in the presence of various metal ions. A molar extinction coefficient of the bismuthate species of 11.1 ± 0.2 L mol-1 cm-1 at 527 nm was determined through modified iodometric titration methods. The dissolution rate of solid NaBiO3 was increased in the presence of smaller cations, presumably resulting from a decrease in steric hindrance during the ion-exchange reaction with Na+. Increasing the charge of the ions in solution, however, increased the stability of BiO3- in solution, reducing the rate of degradation from Bi(V) to Bi(III) with a near linear correlation as a function of countercation charge. The presence of U(VI), as UO22+, increased the BiO3- equilibrium concentration and resulted in notable changes of the BiO3- absorbance band, indicating an interaction between the uranyl cation and bismuthate anion.
