Solubility of Thorium(IV) in the Presence of Oxalic and Malonic Acids

Abstract

The solubility of thorium(IV) in the presence of oxalic and malonic acids was measured in acidic and neutral pH using the oversaturation method. In the weakly acidic and neutral pH regions, the apparent solubility in the presence of carboxylic acids was higher than that in the absence of the acids, due to the formation of soluble carboxylate complexes. Under acidic conditions, the precipitation of oxalate salt influenced the apparent solubility in the presence of oxalic acid, while no precipitate was observed in the presence of malonic acid. The solubility product was obtained for the solubility-limiting phase from the analysis of the solubility data.