EXAFS investigation of the interaction of hafnium and thorium with humic acid and Bio-Rex 70

Denecke, Melissa A.; Bublitz, Donald E.; Kim, J. I.; Moll, Henry; Farkes, I.

doi:10.1107/s0909049598013478

Cited by 22 publications

(15 citation statements)

References 9 publications

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“…Organic colloids in surface and groundwaters include humic acid (HA) and fulvic acid (FA). Systematic investigations of metal binding properties of HA implicate carboxylate groups as the primary HA functional groups involved in metal cation binding (2,3). The sorption behavior of minerals such as clays for metal cations, including heavy metals and radionuclides, dramatically changes in the presence of humic substances (4,5).…”

Section: Introductionmentioning

confidence: 99%

Soft X-Ray Spectromicroscopy Investigation of the Interaction of Aquatic Humic Acid and Clay Colloids

Rothe

Denecke

Dardenne

2000

Journal of Colloid and Interface Science

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Section: Introductionmentioning

confidence: 99%

Soft X-Ray Spectromicroscopy Investigation of the Interaction of Aquatic Humic Acid and Clay Colloids

Rothe

Denecke

Dardenne

2000

Journal of Colloid and Interface Science

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“…To contribute to the understanding of these interactions, studies were carried out with synthetic polycarboxylic acids (PCA) [5][6][7][8][9]. Carboxylic functions were chosen as they are known to be the most important interacting groups between metal ions and humic substances, at least for slightly acidic pH values [10,11]. *Author for correspondence (E-mail: montavon@subatech.in2p3.fr).…”

Section: Introductionmentioning

confidence: 99%

Complexation and luminescence spectroscopic studies of europium(III) with polymaleic acid

Montavon¹,

Markai²,

Billard³

et al. 2002

Radiochimica Acta

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Eu / Polycarboxylic acid / Complexation / Laser spectroscopySummary. The complexation behavior of europium(III) with polymaleic acid (PMA) was studied at pH 5 in 0.1 M NaClO 4 by anion exchange (AE). The concentration range investigated was from 10 −9 M to 10 −4 M for the europium ion and from 1 to 50 mg/l for the polymer. The quantitative description of experimental data showed the formation of a 1 : 1 Eu : PMA complex and the existence of at least two distinct interaction environments ("sites") of Eu with the polymer chain whose proportions varied with the ratio between total Eu and PMA concentrations. The existence of different sites was further demonstrated by Time Resolved Laser-induced Fluorescence Spectroscopy (TRLFS) measuring the lifetimes and emission spectra of EuPMA complexes. By using empirical relationships, environments implying 1 : 2 and 1 : 1 Eu : COO − coordination could be deduced. The results show similarities with published data obtained for fulvic and Aldrich humic acids as far as complexation properties at pH = 5 are concerned.

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“…The works of Denecke et al [46] (EXAFS) and Schild and Marquardt [47] (XPS) clearly showed that the carboxylate functional groups are primarily responsible for an important role in the humic complexation of Th(IV) in acidic media. However, this would not be entirely the case for Th-HA bonding in neutral to slightly acidic media.…”

Section: Ta B L Ementioning

confidence: 99%

“…Denecke et al [46] and Schild and Marquardt [47] showed that under acidic conditions the Th-HA bonding occurs through carboxylate functions. However, the increasing complexing strength of HA with pH cannot be explained solely by complexation with HA carboxylate functions.…”

Section: Introductionmentioning

confidence: 99%

On the study of Th(IV)-humic acid interactions by competition sorption studies with silica and determination of global interaction constants

Reiller¹,

Moulin²,

Casanova³

et al. 2003

Radiochimica Acta

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http://www.radiochimacta.deInternational audienceThe influence of humic acids (HA) on the retention of thorium (IV) onto the surface of silica colloids is investigated. Thorium is considered as an analogue of tetravalent actinides (U, Np, Pu), except for the fact that it has no f electrons. Silica (SiO2) is chosen as a model surface because it is a component of many minerals and because of its weak HA sorption properties. Retention experiments are performed by batch procedure at constant ionic strength (I = 0.1M NaClO4), at various pH (2 to 9) and HA concentrations (1–100 mg/L). The sorption of Th(IV) onto colloidal amorphous silica is characterised using a surface complexation model. The ternary system (i.e. HA-Th-Silica) clearly shows the influence of HA on Th(IV) retention. This can lead to a strong reduction of the amount of Th(IV) sorbed onto silica in the presence of HA compared to silica colloids without HA, due to a predominant part of thorium present in solution as humic complexes. In a pH range where no organic coating onto silica occurs, there is a competitive reaction between Th(IV) sorption onto the silica surface and onto HA reactive functional groups. In this case, Schubert's method is applied to obtain a global interaction constant for the Th(IV)-HA system. The large interaction constant values indicate a strong affinity of HA for Th(IV)

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EXAFS investigation of the interaction of hafnium and thorium with humic acid and Bio-Rex 70

Cited by 22 publications

References 9 publications

Soft X-Ray Spectromicroscopy Investigation of the Interaction of Aquatic Humic Acid and Clay Colloids

Soft X-Ray Spectromicroscopy Investigation of the Interaction of Aquatic Humic Acid and Clay Colloids

Complexation and luminescence spectroscopic studies of europium(III) with polymaleic acid

On the study of Th(IV)-humic acid interactions by competition sorption studies with silica and determination of global interaction constants

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