Complexation of Plutonium(IV) with trans-1,2-Diaminocyclohexane-N,N,N',N'-tetraacetic Acid (CDTA) in Acidic Solution
Understanding the interaction of Pu(IV) with complexing agents present in the nuclear fuel cycle is important for predicting the performance of used nuclear fuel separations. The complexation of Pu(IV) with trans-1,2-diaminocyclohexane-N,N,N’,N’-tetraacetic acid (CDTA) was studied in acidic solutions of 0.10 0.50 mol∙L-1 HClO4 with 1.00 mol∙L-1 (Na,H)ClO4 total ionic strength by a liquid–liquid extraction method using tracer quantities of 238Pu. The acid dissociation constants of CDTA and the autoprotolysis constant of water were determined via potentiometric titrations in 0.10–2.00 mol∙L-1 NaClO4 and 25.0 ± 0.1 °C. The variation of the dissociation constants with ionic strength was modeled with the Specific ion Interaction Theory (SIT) and the associated SIT parameters were obtained. The thermodynamic dissociation 23 constants at zero ionic strength for water and CDTA were determined from this analysis as PK$$^o_w$$ = 14.00 ± 0.03, PK$$^o_{a2}$$ = 1.52 ± 0.04, PK$$^o_{a3}$$ = 2.78 ± 0.05, PK$$^o_{a4}$$ = 4.17 ± 0.04, PK$$^o_{a5}$$ = 6.75 ± 0.02, and PK$$^o_{a6}$$ = 10.64 ± 0.04 at 25.0 ± 0.1 °C. The results of the liquid–liquid extraction experiments indicated the formation of a 1:0:1 complex, PuCDTAo, and the presence of additional protonated species, Pu(HCDTA)+ and Pu(H2CDTA)2+, at these acidities. The corresponding stability constants in 1.00 mol·L-1 (Na,H)ClO4 and 23 ± 1 °C were determined to be log10 β101=24.2 ± 0.3, log10 β111 =25.4 ± 0.2, and log10 β121 = 25.8 ± 0.1.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Washington State Univ., Pullman, WA (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Nuclear Energy (NE)
- Grant/Contract Number:
- AC52-07NA27344; NA0002916
- OSTI ID:
- 1548379
- Alternate ID(s):
- OSTI ID: 1529249
- Report Number(s):
- LLNL-JRNL-776832; 969848
- Journal Information:
- Journal of Solution Chemistry, Vol. 48, Issue 2; ISSN 0095-9782
- Publisher:
- SpringerCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Similar Records
Solubility of B-Nb2O5 and the Hydrolysis of Niobium(V) in Aqueous Solution as a Function of Temperature and Ionic Strength
Cationic polymerization of styrene by methanesulfonic acid in dichloromethane