Nitric Acid and Water Extraction by T2EHDGA in n-Dodecane

ABSTRACT

Liquid–liquid distribution behavior of nitric acid (HNO₃) and water by a diglycolamide (DGA) ligand, N,N,N’,N’-tetra-2-ethylhexyldiglycolamide (T2EHDGA), into n-dodecane diluent was investigated. Spectroscopic Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) characterization of the organic extraction solutions indicate the T2EHDGA carbonyl coordinates with HNO₃ and progressively aggregates at high acid conditions. Water extraction increases in the presence of HNO₃. The experimentally observed distribution of HNO₃ was modeled using the computer program SXLSQI. The results indicated that the formation of two organic-phase species—HNO₃·T2EHDGA and (HNO₃)₂·T2EHDGA—satisfactorily describes the acid distribution behavior. Temperature-dependent solvent extraction studies allowed for the determination of thermodynamic extraction constants and ΔH and ΔS parameters for the corresponding extractive processes.

KEYWORDS:

• ALSEP
• T2EHDGA
• speciation model
• trivalent actinides and lanthanides
• extraction constant

Funding

This work was supported by U.S. Department of Energy, Office of Nuclear Energy, through the Fuel Cycle Research and Development Program. Pacific Northwest National Laboratory is operated by Battelle Memorial Institute for the U.S. Department of Energy under contract DE-AC05-76RL01830.

Additional information

Funding

This work was supported by U.S. Department of Energy, Office of Nuclear Energy, through the Fuel Cycle Research and Development Program. Pacific Northwest National Laboratory is operated by Battelle Memorial Institute for the U.S. Department of Energy under contract DE-AC05-76RL01830.