Chelating ion exchange with macroreticular hydroxamic acid resins

Phillips, R. J.

doi:10.31274/rtd-180813-11645

Cited by 1 publication

(2 citation statements)

References 26 publications

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“…(2a)). This is consistent with the pK a for FHA being less than that for AHA, 8.78 and 9.02 respectively [17][18], leading to the expectation that FHA will form less strong complexes with metal ions.…”

Section: +supporting

confidence: 81%

“…given that the pK a of both hydroxamic acids investigated in this study and subsequent papers in this series are greater than 8.5 (pK a (FHA) = 8.78 [17]; pK a (AHA) = 9.02 [18]), under the conditions employed in the experiments described below (pH < 1), the dominant form of the free ligand will be the acid rather than the deprotonated conjugate base. Thus, direct hydrolysis of the hydroxamate ion may be neglected.…”

Section: Speciation and Kinetic Modelling Of Metal-hydroxamic Acid Symentioning

confidence: 76%

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The Hydrolysis of Hydroxamic Acid Complexants in the Presence of Non-Oxidizing Metal Ions 2: Neptunium (IV) Ions

et al. 2007

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Hydroxamic acids are salt free, organic compounds with affinities for cations such as Fe 3+ , Np 4+ and Pu 4+ 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 diferent pH and ligand to metal ratios. A kinetic model that describes the instability of the complex due to the hydrolysis of the hydroxamate moeity, previously developed for the Fe(III)-AHA complexes [1], 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.

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Section: +supporting

confidence: 81%

Section: Speciation and Kinetic Modelling Of Metal-hydroxamic Acid Symentioning

confidence: 76%