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Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - The hydrolysis of hydroxamic acid complexants in the presence of non-oxidizing metal ions 2: Neptunium (IV) ions.
AU - Andrieux, Fabrice Pierre Louis
AU - Boxall, C.
AU - May, I.
AU - Taylor, R. J.
N1 - The original publication is available at www.springerlink.com
PY - 2008/2
Y1 - 2008/2
N2 - Hydroxamic acids are salt free, organic compounds with affinities for cations such as Fe3+, Np4+ and Pu4+, and have been identified as suitable reagents for the control of Pu and Np in advanced nuclear fuel reprocessing. The results of a UV-visible, near-IR spectrophotometric study of the 1:1 and 2:1 complexes formed between formo- and aceto-hydroxamic acids (FHA, AHA) and Np(IV) ions are interpreted using speciation diagrams for the identification of the species present at different pH and ligand to metal ratios. A kinetic model that describes the instability of the complex due to hydrolysis of the hydroxamate moiety, previously developed for the Fe(III)-AHA complexes (Andrieux et al. in J. Solution Chem. 36:1201-1217, [2007]), is tested here against experimental Np(IV)-FHA data. Consequently, the complexation constant for formation of the 1:1 Np(IV)-FHA complex in nitric acid is estimated at K-1=2715 and indications are that complexation protects the ligand against hydrolysis at 0.1 > pH >-0.1.
AB - Hydroxamic acids are salt free, organic compounds with affinities for cations such as Fe3+, Np4+ and Pu4+, and have been identified as suitable reagents for the control of Pu and Np in advanced nuclear fuel reprocessing. The results of a UV-visible, near-IR spectrophotometric study of the 1:1 and 2:1 complexes formed between formo- and aceto-hydroxamic acids (FHA, AHA) and Np(IV) ions are interpreted using speciation diagrams for the identification of the species present at different pH and ligand to metal ratios. A kinetic model that describes the instability of the complex due to hydrolysis of the hydroxamate moiety, previously developed for the Fe(III)-AHA complexes (Andrieux et al. in J. Solution Chem. 36:1201-1217, [2007]), is tested here against experimental Np(IV)-FHA data. Consequently, the complexation constant for formation of the 1:1 Np(IV)-FHA complex in nitric acid is estimated at K-1=2715 and indications are that complexation protects the ligand against hydrolysis at 0.1 > pH >-0.1.
KW - formohydroxamic acid
KW - acetohydroxamic acid
KW - advanced Purex
KW - neptunium
KW - complexation
KW - speciation
KW - hydrolysis
KW - kinetics
KW - NUCLEAR-FUEL
KW - NITRIC-ACID
KW - FLOWSHEETS
KW - SEPARATION
KW - REDUCTION
U2 - 10.1007/s10953-007-9225-3
DO - 10.1007/s10953-007-9225-3
M3 - Journal article
VL - 37
SP - 215
EP - 232
JO - Journal of Solution Chemistry
JF - Journal of Solution Chemistry
SN - 0095-9782
IS - 2
ER -