Solvent extraction of thorium (IV) from chloride solution using Schiff base and its application for spectrophotometric determination

Thorium (IV) was separated from chloride medium by solvent extraction with Schiff base chelating agent, (E)-4-(2-hydroxyphenyl imino) pentane-2-one (AcPh) that was prepared and characterized by FT-IR, 1H NMR, and elemental analysis. The extraction step was studied with regard to experimental parameters such as diluent type, pH, AcPh concentration, A:O ratio, contact time, temperature and interference of diverse ions on the recovery of thorium ion. The thorium (IV) was then back-extracted into aqueous media containing 0.5 M HNO3 to study the stripping conditions that were A:O ratio, contact time and room temperature. The optimum parameters were applied in the studied sample solution for the spectrophotometric determination at 540 nm with Thoron I. The accuracy of the developed method was tested with B2 standard reference material. Furthermore, the proposed method was successfully applied for the spectrophotometric determination of thorium ions in the geologic sample with good accuracy and precision.