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Determination of the Structures of Uranyl–Tri‐ n ‐butyl‐Phosphate Aggregates by Coupling Experimental Results with Molecular Dynamic Simulations
Author(s) -
Guilbaud Phillipe,
Berthon Laurence,
Louisfrema Wilfried,
Diat Olivier,
Zorz Nicole
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201703967
Subject(s) - uranium , purex , uranyl , chemistry , extraction (chemistry) , molecular dynamics , actinide , tributyl phosphate , stoichiometry , uranyl nitrate , phase (matter) , inorganic chemistry , analytical chemistry (journal) , materials science , computational chemistry , chromatography , organic chemistry , metallurgy , solvent extraction
The complex structure of a plutonium uranium refining by extraction (PUREX) process organic phase was characterized by combining results from experiments and molecular dynamics simulations. For the first time, the molecular interactions between tri‐ n ‐butyl phosphate (TBP) and the extracted solutes, as well as TBP aggregation after the extraction of water and/or uranyl nitrate, were described and analyzed concomitantly. Coupling molecular dynamics simulations with small‐ and wide‐angle X‐ray scattering (SWAXS) experiments can lead to simulated organic solutions that are representative of the experimental ones, even for high extractant and solute concentrations. Furthermore, this coupling is well adapted for the interpretation of SWAXS experiments without preliminary hypothesis on the size or shape of aggregates. The results link together previous literature studies obtained for each level of depiction separately (complexation or aggregation). Without uranium, or at low metal concentration, almost no aggregation was observed. At high uranium concentration, organic phases contain small [UO 2 (NO 3 ) 2 (TBP) 2 ] n polymetallic aggregates (with n =2 to 4), in which the 1:2 U/TBP stoichiometry is preserved.