Investigation of Americium Sorption from Model Liquid Radwaste Solutions Using TODGA-Based Solid-Phase Extractant

Resumo

The purpose of this work is to investigate the sorption of americium from model solutions of liquid radwastes using modified solid-phase extracting agents based on TODGA as an alternative method of additional purification of liquid radwaste by removing transuranium elements by means of alkali precipitation. The kinetic parameters of uranium and americium sorption from highly saline weakly acidic (pH ~3.4) model solutions of liquid radwaste with americium content ~0.04 mg/liter were determined for three modified samples synthesized at VNIIKhT and one analog of a TODGA sample from the AXION Company. The time to equilibrium of all experimental samples in terms of americium is almost the same and equals ~240 min. The equilibrium concentration of uranium is reached in approximately 800 min. The salting-out effect in the extraction of uranium and americium from salt solutions is revealed, though this effect is much weaker for uranium than for americium. The most promising sorbent was determined – sample 7. Its distribution factor is 1.4 times higher than that of the AXION sample and the pair distribution factor Am/U is a factor of 2 higher.