f-Element Ion Chelation in Highly Basic Media - Final Report
A large body of data has been collected over the last fifty years on the chemical behavior of f-element ions. The ions undergo rapid hydrolysis reactions in neutral or basic aqueous solutions that produce poorly understood oxide-hydroxide species; therefore, most of the fundamental f-element solution chemistry has allowed synthetic and separations chemists to rationally design advanced organic chelating ligands useful for highly selective partitioning and separation of f-element ions from complex acidic solution matrices. These ligands and new examples under development allow for the safe use and treatment of solutions containing highly radioactive species. This DOE/EMSP project was undertaken to address the following fundamental objectives: (1) study the chemical speciation of Sr and lanthanide (Ln) ions in basic aqueous media containing classical counter anions found in waste matrices; (2) prepare pyridine N-oxide phosphonates and phosphonic acids that might act as selective chelator s for Ln ions in model basic pH waste streams; (3) study the binding of the new chelators toward Ln ions and (4) examine the utility of the chelators as decontamination and dissolution agents under basic solution conditions. The project has been successful in attacking selected aspects of the very difficult problems associated with basic pH solution f-element waste chemistry. In particular, the project has (1) shed additional light on the initial stages of Ln ion sol-gel-precipitate formulation under basic solution conditions; (2) generated new families of pyridine phosphonic acid chelators; (3) characterized the function of the chelators and (4) examined their utility as oxide-hydroxide dissolution agents. These findings have contributed significantly to an improved understanding of the behavior of Ln ions in basic media containing anions found in typical waste sludges as well as to the development of sludge dissolution agents. The new chelating reagents are easily made and could be prepared in quantities suitable for large scale decontamination and dissolution processes involving sludges. Further studies will be required to assess specific performance in actinide ion bearing wastes.
- Research Organization:
- Univ. of New Mexico, Albuquerque, NM (US)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- FG07-96ER14736
- OSTI ID:
- 780098
- Report Number(s):
- DOE/ER/14736; Project Number 54595; Project Number 54595; TRN: US0106131
- Resource Relation:
- Other Information: PBD: 12 Dec 2000
- Country of Publication:
- United States
- Language:
- English
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F-Element ion chelation in highly basic media. Annual progress report, October 1, 1996--July 1, 1997
Advanced Extraction Methods for Actinide/Lanthanide Separations
Related Subjects
DECONTAMINATION
DISSOLUTION
PHOSPHONIC ACIDS
PYRIDINE
SLUDGES
HYDROLYSIS
IONS
CHELATING AGENTS
RADIOACTIVE WASTE PROCESSING
STRONTIUM
LANTHANUM
F-ELEMENT IONS
OXIDE-HYDROXIDE SPECIES
ACIDIC SOLUTION
LIGANDS
FISSION PRODUCTS
PARTITIONING
IMMOBILIZATION
CHELATORS
LN IONS