TITLE:
Influence of Co-Solvent on the Extraction Behaviour of Uranium and Thorium Nitrates with Organophosphorous Compounds
AUTHORS:
K. C. Pitchaiah, K. Sujatha, C. V. S. Brahmmananda Rao, N. Sivaraman, T. G. Srinivasan, K. Nagarajan, P. R. Vasudeva Rao
KEYWORDS:
Co-Solvent, Uranium and Thorium, Organophosphorous Compounds
JOURNAL NAME:
International Journal of Analytical Mass Spectrometry and Chromatography,
Vol.2 No.2,
June
30,
2014
ABSTRACT: Supercritical Fluid Extraction (SFE) is emerging as a powerful technique in the extraction of metal ions. In the present study, the extraction of nitrates of uranium and thorium was carried out using supercritical carbon dioxide (Sc-CO2) modified with various organophosphorous compounds such as dialkylalkyl phosphonates, trialkyl phosphates and trialkyl phosphine oxides in the presence of co-solvents such as methanol, dichlormethane and n-hexane. The influence of ligand and co-solvent on the extraction of the metal nitrates was studied in detail. These studies have established that co-solvent plays an important role in the extraction as well as fractionation of uranium and thorium nitrates. Polar co-solvent, methanol provided faster extraction without fractionation whereas the non-polar solvent, e.g. n-hexane provided some fractionation of metal nitrates though the extraction kinetics was slower.