Determination of Co(II) and Ni(II)-humate stability constants at high ionic strength NaCl solutions

Kurk, David N.; Choppin, Gregory R.

doi:10.1524/ract.2000.88.9-11.583

Cited by 15 publications

(17 citation statements)

References 5 publications

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“…1 presents the curves (α HA vs. pcH) obtained from the titrations of the HA at 0.10 and 3.0 m NaCl. The values of pK a1 and pK a2 of this humic acid were measured previously in this laboratory at I = 0.10, 0.30, 1.0, 3.0 and 5.0 m [17] and values obtained in this work at 0.30 and 5.0 m NaCl were in good agreement. No significant variation occurs in these constants between 0.10 and 5.0 m so the values in Table 2 for the range of ionic strengths were used to obtain the β 1 values.…”

Section: Resultssupporting

confidence: 87%

Interaction study between Ca²⁺ and humic acids in brine media

Laszak¹,

Choppin²

2001

Radiochimica Acta

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Section: Resultssupporting

confidence: 87%

Interaction study between Ca²⁺ and humic acids in brine media

Laszak¹,

Choppin²

2001

Radiochimica Acta

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“…However, different binding behaviors are observed for I > 1 m. Specifically, UO 2 2+ -and Pu 4+ -HA complexation constants increase with increasing ionic strength (Labonne- Wall et al, 1999;Szabò et al, 2010), whereas Co 2+ -HA complexation does not vary substantially, and Ni 2+ -HA complexation slightly decreases (Kurk and Choppin, 2000) with increasing ionic strength.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, pH measurement is non-trivial in saline solutions. More specifically, "constant pH values" can refer to constant proton activity (pH =log ; Szabò et al, 2010), proton molality (pH m = -log ; Czerwinski et al, 1996;Labonne-Wall et al, 1999;Wall et al, 2002), or constant experimental values, as read on the pHmeter (pH exp ; Kurk and Choppin, 2000; where the pH exp -pH m relationship is provided). Deviation between pH, pH m and pH exp as affected by I may also hamper comparison between different datasets.…”

Section: Introductionmentioning

confidence: 99%

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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“…The structure of most of these substances possesses functional groups, such as carboxylic, phenolic, hydroxyl, carbonyl, amine, amide, and aliphatic moieties, among others. Because of their polyfunctionality, HAs are considered one of the most powerful chelating agents among existing natural organic substances; they are capable of complexing heavy metals,11, 12 inorganic anions and halides,13, 14 organic acids,15 aromatic compounds,16, 17 pesticides, and herbicides 18, 19. Previous studies have demonstrated the importance of HA interaction with a variety of contaminants; they form complexes of different solubility and chemical and biochemical stability.…”

Section: Introductionmentioning

confidence: 99%

Humic acid/polypyrrole on a paraffin‐impregnated graphite electrode and its use in arsenic extraction

Antilén

Armijo

2009

J of Applied Polymer Sci

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A novel and simple electrode with rapid preparation was developed with humic acid (HA) and polypyrrole (PPy) films. The method for modified electrode preparation embraced the abrasive transfer technique on a paraffin-impregnated graphite electrode (PIGE) followed by the electrochemical incorporation of a PPy polymeric film upon bare PIGE and PIGE/HA electrodes. Cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry were used for the study of the modified electrodes. Morphological characterization was performed by scanning electron microscopy. The obtained results demonstrated that the presence of HA did not affect the electrical properties of the system but indeed provoked changes in the polymer morphology, turning it more granular. Next, PIGE/HA/ PPy was tested in arsenic solutions [As(V)] because arsenic contamination of water is an important worldwide environmental issue because of the sources of arsenic contamination of water come from both natural processes and anthropogenic activities. The modified electrode displayed good and reversible extraction properties toward the analyte in acid medium and was 18% more efficient than a previously reported PPy-modified electrode (PIGE/PPy). From an environmental standpoint, this novel application of conductive polymer properties with the chelating capacity of humic substances constitutes a first step in the development of more efficient technologies for the removal of contaminants present in soilwater media.

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Determination of Co(II) and Ni(II)-humate stability constants at high ionic strength NaCl solutions

Cited by 15 publications

References 5 publications

Interaction study between Ca²⁺ and humic acids in brine media

Interaction study between Ca²⁺ and humic acids in brine media

Modeling metal ion-humic substances complexation in highly saline conditions

Humic acid/polypyrrole on a paraffin‐impregnated graphite electrode and its use in arsenic extraction

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Determination of Co(II) and Ni(II)-humate stability constants at high ionic strength NaCl solutions

Cited by 15 publications

References 5 publications

Interaction study between Ca2+ and humic acids in brine media

Interaction study between Ca2+ and humic acids in brine media

Modeling metal ion-humic substances complexation in highly saline conditions

Humic acid/polypyrrole on a paraffin‐impregnated graphite electrode and its use in arsenic extraction

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Interaction study between Ca²⁺ and humic acids in brine media

Interaction study between Ca²⁺ and humic acids in brine media