Neptunium (V) Solubility in WIPP Brine: Presence and Absence of WIPP-Relevant Organic and Inorganic Ligands
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
The oxidation state and solubility of neptunium (Np) in 5 M NaCl and high ionic strength synthetic WIPP (Waste Isolation Pilot Plant) brines were systematically investigated as a function of pCH+ (7-11) in the presence and absence of WIPP-relevant organic ligands, including EDTA (Ethylenediaminetetraacetic acid), oxalate, citrate, and acetate, as well as inorganic ligands such as borate and carbonate at a temperature of 23 ± 2°C. This study was conducted through long-term batch solubility experiments spanning approximately 950 days, using an undersaturation approach. A comprehensive set of experimental and spectroscopic techniques, including UV-VIS-NIR spectroscopy and Np LIII-edge X-ray Absorption Spectroscopy (XAS), was employed to identify the solubility-controlling Np solid phases and the predominant aqueous Np species present in the samples.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- 89233218CNA000001
- OSTI ID:
- 2999875
- Report Number(s):
- LA-UR--25-30095
- Country of Publication:
- United States
- Language:
- English
Similar Records
Technetium Complexation with Multidentate Carboxylate-Containing Ligands: Trends in Redox and Solubility Phenomena
Effects of Borate and Organics on U(VI) Solubility in WIPP Brine