Extraction thermodynamics of Th(IV) in various aqueous organic systems

Thermodynamic studies on solvent extraction of Th(IV) have been carried out using TBP and HDEHP as extractants in toluene from aqueous bromide and iodide media containing Arsenazo-III as a colouring reagent. This reagent was used for the spectrophotometric determination of Th(IV). The study was carried out at T = {(283, 298, 313) ± 1} K to evaluate lg Kex as well as the thermodynamic functions ΔG∘, ΔH∘, and ΔS∘ of the extraction reactions. The extracted species and the overall extraction mechanisms are postulated.