Interaction study between Ca<sup>2+</sup> and humic acids in brine media

Laszak, I.; Choppin, Gregory R.

doi:10.1524/ract.2001.89.10.653

Cited by 6 publications

(7 citation statements)

References 32 publications

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“…Although proton titrations of HA are rarely carried out for I > 1 m, a number of critical studies do exist. Kurk and Choppin (2000) and Laszak and Choppin (2001) performed proton titrations of HA at I = 0.1, 0.3, 1, 3 and 5 m (NaCl), and calculated apparent dissociation constants (pK a ) for HA considering two acidic groups. They found that pK a variation was insignificant (±0.1) within this range of ionic strengths.…”

Section: Proton Titration In Saline Solutionsmentioning

confidence: 99%

“…In a number of laboratory studies, Choppin and co-workers (Labonne- Wall et al, 1999;Kurk and Choppin, 2000;Laszak and Choppin, 2001;Wall et al, 2002) to metal ions and must therefore be taken into account in the calculations (Labonne-Wall et al, 1999;Wall et al, 2002). Finally, unlike the other cations, for pH m ≈ 5 under ambient (air) atmosphere, UO 2 2+ hydrolysis and complexation by carbonate anions cannot be neglected (Langmuir, 1978;Labonne-Wall et al, 1999 and Ni 2+ ) and Laszak and Choppin (2001)…”

Section: Cation-ha Complexation In Nacl Solutionsmentioning

confidence: 99%

“…The reported M-HA complexation constants pertain to the PM (Labonne- Wall et al, 1999;Kurk and Choppin, 2000;Laszak and Choppin, 2001;Wall et al, 2002). For the studies listed in Table 1, 5 0 values were determined for each pH and I from HA proton titrations for the specific metal ion-HA complexation studies.…”

Section: Cation-ha Complexation In Nacl Solutionsmentioning

confidence: 99%

“…. Figure 5 shows HA K(Ca 2+ ) measured by Laszak and Choppin (2001) for Ao9 = 0.1, 1 and 3 m at various pH m under ambient atmosphere. The originally reported constants were corrected for side reactions (including Ca complexation to chloride and carbonate).…”

Section: Ca(ii)mentioning

confidence: 99%

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Modeling metal ion-humic substances complexation in highly saline conditions

Marsac

Banik

Lützenkirchen

et al. 2017

Applied Geochemistry

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International audienceBecause highly saline groundwaters are found at potential repository sites for nuclear waste, geochemical models should predict the speciation of relevant radionuclides in brines, including their complexation with substances such as humic acids (HA). In this study, available experimental radionuclide-HA complexation data in high 1:1 background electrolyte solutions (0.01 < mNaCl/NO3/ClO4mNaCl/NO3/ClO4 < 4 molal, m) are reviewed. Discrepancies in the amplitude of ionic strength effects on radionuclide-HA complexation are observed, which might depend on the nature of the interacting radionuclide or on the origin of HA. However, significant differences in the experimental conditions and calculations applied to determine conditional metal ion-HA complexation constants hamper direct comparison between these datasets. To clarify whether metal ion-HA binding in saline solutions can be described, two sophisticated humic-ion binding models (Model VII and NICA-Donnan) are presently used. This is the first time that Model VII and NICA-Donnan are applied to predict metal ion-HA binding at high ionic strength (I > 1 m). The advantage of these models, compared to more simple ones (e.g., the polyelectrolyte or the charge neutralization models), is that both electrostatic and chemical contributions to the overall metal ion-HA binding are explicitly taken into account. Model VII and NICA-Donnan are shown to produce very similar results. Trends in conditional metal ion-HA binding constants and in the maximum metal ion uptake by HA (e.g., the loading capacity) with I agree with experiments. The present data evaluation suggests that most of the apparent discrepancies between various experimental datasets arise from differences in the experimental conditions. Both Model VII and NICA-Donnan predict that the specific ion interaction theory (SIT) parameters for metal ion-HA systems, which are required for high ionic strength with more simple models, vary with pH and metal loading. Overall, Model VII and NICA-Donnan are able to account for various mechanisms involved in metal ion-HA complexation, including the metal loading effects and cation competition, and might be helpful predictive tools for performance safety assessment up to highly saline conditions

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Section: Proton Titration In Saline Solutionsmentioning

confidence: 99%

Section: Cation-ha Complexation In Nacl Solutionsmentioning

confidence: 99%

Section: Cation-ha Complexation In Nacl Solutionsmentioning

confidence: 99%

Section: Ca(ii)mentioning

confidence: 99%

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Modeling metal ion-humic substances complexation in highly saline conditions

Marsac

Banik

Lützenkirchen

et al. 2017

Applied Geochemistry

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“…For the systems where Ca 2 + interacts with humic acid, one of the naturallyoccurring organic substances, the slope of the log K d vs. pH plots is reported to get smaller with an increase of NaCl concentrations. 13) 1.00…”

Section: Subtiusmentioning

confidence: 99%

Association of Eu(III) and Cm(III) with Bacillus subtilis and Halobacterium salinarum

Ozaki

Gillow

Francis

et al. 2002

Journal of Nuclear Science and Technology

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Adsorption behavior of Eu(III) and Cm(lll) by Bacillus subtilis and Halobacterium salinarum was investigated. Both microorganisms showed almost identical pH dependence on the distribution ratio (K d ) of the metals examined, i.e., K d of Eu(lll) and Cm(lll) increased with an increase of pH. The coordination state of Eu(lll) adsorbed on the microorganisms was studied by time-resolved laser-induced fluorescence spectroscopy (TRLFS). The coordination states of Eu(lll) adsorbed on the B. subtilis and H. salinarum was of different characteristics. H. salinarum exhibited more outer-spherical interaction with Eu(III) than B. subtilis.

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