In Situ Preconcentration during the Di-(2-ethylhexyl) Phosphoric Acid-Assisted Dissolution of Uranium Trioxide in an Ionic Liquid: Spectroscopic, Electrochemical, and Theoretical Studies

Parveen K Verma; Bholanath Mahanty; Sk Musharaf Ali; Prasanta K Mohapatra

doi:10.1021/acs.inorgchem.1c00202

In Situ Preconcentration during the Di-(2-ethylhexyl) Phosphoric Acid-Assisted Dissolution of Uranium Trioxide in an Ionic Liquid: Spectroscopic, Electrochemical, and Theoretical Studies

Inorg Chem. 2021 Jul 19;60(14):10147-10157. doi: 10.1021/acs.inorgchem.1c00202. Epub 2021 Jul 2.

Authors

Parveen K Verma¹, Bholanath Mahanty¹, Sk Musharaf Ali², Prasanta K Mohapatra¹

Affiliations

¹ Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085, India.
² Chemical Engineering Division, Bhabha Atomic Research Centre, Mumbai 400085, India.

PMID: 34212725
DOI: 10.1021/acs.inorgchem.1c00202

Abstract

Dissolution of uranium oxide was carried out using a solution of HD2EHP in C₈mim·NTf₂, which was apparently facilitated by the in situ generation of water during the complex formation reaction. The dissolved complex in the ionic liquid phase led to splitting of the latter into a light phase and a heavy phase where the former contained predominantly the UO₂(HL₂)₂ complex (HL = HD2EHP), while the latter contained the ionic liquid as supported by FTIR and UV-Visible spectral analyses. The complexation of the uranyl ion was suggested to take place in the equatorial plane where two dimeric units of the H-bonded HD2EHP molecules took part in complexation. An increase in temperature facilitated the dissolution rate with an activation energy of 31.0 ± 2.8 kJ/mol. The cyclic voltammetry studies indicated potential chances of recovery of the dissolved uranium by electrodeposition at the cathode. The proposed dimeric structure of HD2EHP in the complexation with U(VI) was supported by DFT studies also.