Extraction of Am(III) and Eu(III) from nitrate solution with purified Cyanex 301

The extraction of tracer amounts of Am(III) and Eu(III) from nitrate medium with purified Cyanex 301(TM) in kerosene was studied. The slopes of logD/pH dependencies for An and Eu are close to 3 and the logD/extractant concentration dependencies for Am and Eu are close to 2, respectively. The calculated extraction constants are 10(-7.85) for Am and 10(-11.62) for Eu at 25 degrees C. Both the extraction constants and the separation factor of Am/Eu decrease with increasing extraction temperature. The extraction enthalpies of Am and Eu are 18.10 kJmol(-1) and 43.65 kJmol(-1), respectively. This extraction system provides a high selectivity for Am(III) over Eu(III) (at 25 degrees C, separation factor SF=5.9x10(3)) which arises from greater covalent bonding tendency between sulfur donor atom and Am(III) in comparison with Eu(III).