RESUMO
The organic soluble extractant bis(2,4,4-trimethylpentyl)dithiophosphinic acid, often called Cyanex 301 (HC301), has shown selectivity for preferentially extracting trivalent actinides over the lanthanides in the treatment of used nuclear fuel. To maintain control and efficiency of a separation process using this extractant, it is necessary to accurately know specific parameters of the system, including the concentration of HC301 in the organic phase, at any given time. Here, the ability to quickly determine the concentration of HC301 in n-dodecane was tested by a one-step permanganometric titration in an organic solution using a double-beam UV-vis spectrophotometer. The addition of HC301 in n-dodecane to solutions of KMnO4 was found to decolorize the KMnO4 solutions, but the HC301 was best quantified in terms of decolorization in acetone. This decolorization allowed for the creation of a linear analytical curve relating the amount of KMnO4 consumed to the amount of HC301 added. Cross-validation of this analytical curve reproduced the known amount of HC301 with an average difference of 1.73% and a maximum of 4.03%.
RESUMO
Adjacent lanthanides are among the most challenging elements to separate, to the extent that current separations materials would benefit from transformative improvement. Ordered mesoporous carbon (OMC) materials are excellent candidates, owing to their small mesh size and uniform morphology. Herein, OMC materials were physisorbed with bis-(2-ethylhexyl) phosphoric acid (HDEHP) and sorption of Eu3+ was investigated under static and dynamic conditions. The HDEHP-OMC materials displayed higher distribution coefficients and loading capacities than current state-of-the-art materials. Using a small, unpressurized column, a separation between Eu3+ and Nd3+ was achieved. Based on these experimental results, HDEHP-OMC have shown potential as a solid phase sorbent for chromatographic, intragroup, lanthanide separations.