Effect of the competition of copper and cobalt on the lability of Ni(II)–organic ligand complexes. Part I. In model solutions containing Ni(II) and a well-characterized fulvic acid

Mandal, Rupasri; Sekaly, Amina L.R.; Murimboh, John; Hassan, Nouri M.; Chakrabarti, Chuni L.; Back, M. H.; Grégoire, D. Conrad; Schroeder, W. H.

doi:10.1016/s0003-2670(99)00350-5

Cited by 25 publications

(7 citation statements)

References 32 publications

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“…The results for the Co contaminated Huelva system were in reasonable agreement with those for the Skagerrak (17−98% labile Co ()) but contrasted with other estuarine and coastal systems where Co complexation with strong ligands was more important ( , ). In the Huelva Estuary, the high [Co T ] was most likely in great excess of Co complexing ligands, with Ni and Cu competing with Co for complexing sites on the ligands ( , ).…”

Section: Resultsmentioning

confidence: 99%

Chemical Speciation of Dissolved Cu, Ni, and Co in a Contaminated Estuary in Southwest Spain and Its Influence on Plankton Communities

Braungardt

Achterberg

Gledhill

et al. 2007

Environ. Sci. Technol.

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Four surveys of the Huelva Estuary in southwest Spain and its sources, the Tinto and the Odiel Rivers, were carried out between 1996 and 1998. The surveys investigated the impact of metalliferous mining of sulfide-rich ores in the catchment area on metal speciation, metal concentrations in a macrophyte, and phytoplankton diversity and abundance. Chemical speciation measurements in the lower Tinto Estuary showed that metals were predominantly electrochemically labile (> 99% of total dissolved Cu, Co, and Ni at 10 microM Cu, 424 nM Co, and 500 nM Ni, S = 28). Concentrations of Cu complexing ligands and free cupric ions [Cu2+] in the Gulf of Cádiz ranged between 5.3 and 38 nM and 0.2-7.9 pM, respectively, with conditional stability constants of the ligands of log K'(CuL) = 11.7-12.6. At enhanced dissolved Cu concentrations in the lower Huelva Estuary, Cu complexing ligands were saturated with Cu, resulting in nanomolar [Cu2+], which increased upstream. Metal tissue concentrations of the macrophyte Blindingia marginata were high, and a clear relationship between dissolved labile Cu and macrophyte tissue Cu concentrations was observed. A low biodiversity was observed in the Huelva system (Shannon-Wiener indices (H) typically < 0.2). Nevertheless, the maximum biomass was observed in the lower Tinto Estuary, which showed high labile metal and nutrient concentrations and a low biodiversity (H < 0.02), thereby suggesting adaptation through evolutionary processes of the phytoplankton community to the harsh conditions.

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Section: Resultsmentioning

confidence: 99%

Chemical Speciation of Dissolved Cu, Ni, and Co in a Contaminated Estuary in Southwest Spain and Its Influence on Plankton Communities

Braungardt

Achterberg

Gledhill

et al. 2007

Environ. Sci. Technol.

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“…Of the transition metals, complexes with Ni dissociate particularly slowly, which can be rationalized, according to the Eigen mechanism, by the relatively slow loss of water molecules from the hydrated cation . Competitive ligand exchange techniques have been used to obtain information on the rates of release of Ni from complexes with known ligands and in samples of natural waters. − These approaches provide useful information, but cannot be used in situ . The technique of diffusive gradients in thin-films (DGT) has also been used to measure the rates of dissociation of Ni–NTA complexes .…”

Section: Introductionmentioning

confidence: 99%

Kinetic Studies of Ni Organic Complexes Using Diffusive Gradients in Thin Films (DGT) with Double Binding Layers and a Dynamic Numerical Model

Arvajeh

Lehto

Garmo

et al. 2012

Environ. Sci. Technol.

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In situ deployments of diffusive gradients in thin films (DGT) can provide direct information on complex dissociation rates in natural waters. Recent advances in understanding the dynamics of the interactions of metal complexes within DGT devices have highlighted the characteristics of the binding layer, but there are few data to complement these theoretical developments. In this work the penetration into the Chelex binding layer of complexes of Ni with nitrilotriacetic (NTA) and Suwannee River fulvic and humic acids (FA and HA) in solution at pH 7 was investigated by deployment of DGT devices with two sequential binding layers, a "front" and a "back" layer. In Ni-NTA experiments, the masses of Ni bound by the front and back binding layers were similar, as predicted for slowly dissociating complexes. For Ni-FA/HA solutions, a higher mass of Ni was taken up by the front binding layer, consistent with fast dissociation from a high proportion of the binding sites. The ratio of Ni in the front to back binding layers was significantly lower (p < 0.05) for solutions of Ni-HA compared to those of Ni-FA, indicating that Ni-HA complexes are less labile than Ni-FA complexes in similar solutions (FA = 10 mg L(-1) and HA = 8 mg L(-1)). A dynamic numerical model of the complexes in a DGT system was used to estimate the dissociation rate constants that provided the best agreement with the experimental data. Values obtained of 2 ± 0.5 × 10(-4) s(-1) for Ni-NTA and 2.5 × 10(-3) s(-1) for Ni-FA when FA = 20 mg L(-1) and 3.42 × 10(-4) s(-1) for Ni-HA when HA = 8 mg L(-1), could be rationalized with current knowledge of the dynamics of these systems. This approach can improve kinetic information obtainable using DGT and widen the range of considered complex labilities.

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“…If organic complexants are present in large excess in freshwaters, metals do not compete with one other, because there are enough biding sites available on the organic complexants to satisfy all the metals present because of the large excess of the organic complexants over the metals (Morel and Hering 1994). Complexation of humic matter with nickel (Mandal et al 1999a(Mandal et al , b, 2000(Mandal et al , 2002Xu et al 2006), with iron and nickel (Ponthieu et al 2006;Jeon et al 2003), with aluminium (Pinheiro et al 2000;Nachtegaal et al 2005;Tipping 2005; Mota et al 1996), with iron and aluminium (Borggaard et al 2005;Tipping et al 2002;Nierop et al 2002), have been described in the literature, but competition studies involving these three metal ions are not found. However, high levels of aluminium and iron in many soils and aquatic environments (Buffle 1990;Bolt et al 1987), decreasing the complexation of transition metals with natural organic ligands and, therefore, their transport, toxicity, and availability.…”

Section: Introductionmentioning

confidence: 99%

Kinetic Speciation of Ni(II) in Model Solutions and Freshwaters: Competition of Al(III) and Fe(III)

Hassan

Murimboh

Chakrabarti

2008

Water Air Soil Pollut

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The competing ligand exchange method was used to investigate the competitive binding of Ni(II) by Al(III) and Fe(III) in model aqueous solutions and freshwaters. Graphite furnace atomic absorption spectrometry and adsorptive cathodic stripping voltammetry were used to monitor the rate of uptake of the Ni by Chelex 100 chelating resin and dimethylglyoxime as the competing ligands, respectively. The results have revealed that Ni(II)-humate complexes were more labile in presence of the mixture of Al(III) and Fe(III), compared to the lability of the Ni(II)-humate complexes when only one of the two, Al(III) or Fe(III), was present. The environmental significance of this work is that in model solutions simulating freshwater containing humic substances and the target trace metal Ni(II) and cations, Al(III) and Fe(III), the competitive binding of Ni(II), Al(III) and Fe(III) by humic substances makes Ni(II)-humate complexes labile, releasing free Ni 2+ -aqua complex, which reported to be toxic.

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Effect of the competition of copper and cobalt on the lability of Ni(II)–organic ligand complexes. Part I. In model solutions containing Ni(II) and a well-characterized fulvic acid

Cited by 25 publications

References 32 publications

Chemical Speciation of Dissolved Cu, Ni, and Co in a Contaminated Estuary in Southwest Spain and Its Influence on Plankton Communities

Chemical Speciation of Dissolved Cu, Ni, and Co in a Contaminated Estuary in Southwest Spain and Its Influence on Plankton Communities

Kinetic Studies of Ni Organic Complexes Using Diffusive Gradients in Thin Films (DGT) with Double Binding Layers and a Dynamic Numerical Model

Kinetic Speciation of Ni(II) in Model Solutions and Freshwaters: Competition of Al(III) and Fe(III)

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