A novel dipicolinamide-dicarbollide synergistic solvent system for actinide extraction

Abstract

Abstract Solvent extraction studies of several actinide ions such as Am(III), U(VI), Np(IV), Np(VI), Pu(IV) were carried out from nitric acid medium using a synergistic mixture of N, N′-diethyl-N, N′-di(para)fluorophenyl-2,6-dipicolinamide, (DEtD(p)FPhDPA, DPA), and hydrogen dicarbollylcobaltate (H+CCD−) dissolved in phenyltrifluoromethylsulphone (PTMS). The effects of different parameters such as aqueous phase acidity (0.01 – 3 M HNO3), oxidation states of metal ions, ligand concentration, nature of diluent and temperature on the extraction behavior of metal ions were studied. The extracted Am(III) species was determined as H+[Am(DPA)2(CCD)4]−. With increasing aqueous phase acidities, the extractability of both Am(III) and Eu(III) was found to decrease. The synergistic mixture showed better extraction in mM concentrations as compared to previously studied dipicolinamides. The thermodynamic studies were performed to calculate heat of extraction reaction and the extraction constants. The proposed synergistic mixture showed good extraction for all the metal ions, though lanthanide actinide separation results are not encouraging.