Kinetic studies of nickel speciation in model solutions of a well-characterized humic acid using the competing ligand exchange method

Guthrie, Jeffrey; Mandal, Rupasri; Salam, Mohamed S. A.; Hassan, Nouri M.; Murimboh, John; Chakrabarti, Chuni L.; Back, M. H.; Grégoire, D. Conrad

doi:10.1016/s0003-2670(02)01590-8

Cited by 42 publications

(28 citation statements)

References 28 publications

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“…The alternative was to add small aliquots (20 mL) of the filtered wastewater sample to standard solutions of the metal ions and measure the peak current. The kinetic model proposed by Oslon and Shuman (1985) has been successfully adapted to the study of dissociation kinetics of Metal complexes of humic substances (Guthrie et al, 2003) using the competing ligand exchange method. Our study applied this model, with some modification, to the study of metal complexation kinetics in tannery wastewater.…”

Section: Introductionmentioning

confidence: 99%

Voltammetric evaluation of binding abilities of tannery effluents by competing ligand exchange method using model solutions of Cr(VI), Ni(II), Cu(II) and Pb(II)

Kiptoo

Ngila

2005

Chemical Speciation & Bioavailability

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Metal complexation capacity (CC) is an important parameter in assessing the quality of wastewaters. In this study, CC and complexation kinetics of tannery wastewater was evaluated using the competing ligand exchange approach with model solutions of Cr(VI), Ni(II), Cu(II) and Pb(II). Ethylenediaminetetraactic acid (EDTA) was used as competing ligand in complexation studies of Cu and Pb while dimethylglyoxime (DMG) and diethylenetriaminepentaacetic acid (DTPA) were used in the case of Ni and Cr, respectively. Determination of labile metal fraction was done using differential pulse anodic stripping voltammetry (DPASV) (Cu and Pb) and differential pulse adsorptive cathodic stripping voltammetry (DPAdCSV) (Ni and Cr) at a hanging mercury drop electrode (HMDE). Flame atomic absorption spectrophotometry (FAAS) was used to determine total and dissolved chromium in the tannery wastewater samples. Results show high complexation capacities (9:03 436:81 mM) and fast kinetics of the tannery effluent, with most of the inert metal species being formed within the first two minutes. The kinetic curves for all the metals showed two kinetically distinguishable components, except for nickel which had an extra component. Speciation results revealed that less than 3% of the chromium in the wastewater was present in the dissolved phase, while no labile forms were detected. The study has demonstrated the role of CC of wastewater in metal speciation and environmental remediation.

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Section: Introductionmentioning

confidence: 99%

Voltammetric evaluation of binding abilities of tannery effluents by competing ligand exchange method using model solutions of Cr(VI), Ni(II), Cu(II) and Pb(II)

Kiptoo

Ngila

2005

Chemical Speciation & Bioavailability

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“…For freshwater animals, the toxic forms of Cu are the free ion Cu 2+ (Lock et al, 2007) and CuOH - (Borgmann, 2005), and for Ni the toxic form is the free ion Ni 2+ (Lock et al, 2007). Park and Kim's (1985) Cu speciation curves provide information on the form of the metal present in our experiments, while Guthrie et al (2003) and Vesper et al (2001) provide information on Ni speciation. Because the pH was stable both in the Blue Chalk Lake and in the Clearwater Lake experiments, metal speciation would also have been stable in our treatments, therefore the decreases in survival were caused by the increase in the metal levels, not by a pH-induced change in speciation during the experiment.…”

Section: N O N -C O M M E R C I a L U S E O N L Ymentioning

confidence: 72%

“…The speciation of metals including the mix of free ionic, hydroxides or salts, is controlled largely by the pH of the medium (Vesper et al, 2001;Guthrie et al, 2003), and some metal species are more toxic than others. For freshwater animals, the toxic forms of Cu are the free ion Cu 2+ (Lock et al, 2007) and CuOH - (Borgmann, 2005), and for Ni the toxic form is the free ion Ni 2+ (Lock et al, 2007).…”

Section: N O N -C O M M E R C I a L U S E O N L Ymentioning

confidence: 99%

Calcium and sodium as regulators of the recovery of four Daphnia species along a gradient of metal and base cations in metal contaminated lakes in Sudbury, Ontario, Canada

2016

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“…[11][12][14][15][16] Cation binding to humic substances include the extreme binding heterogeneity of these natural materials, the variable stoichiometry of binding, the competition between specifically-bound ions, especially protons and metal ions, and electrostatic effects which give rise to ionic strength effects and the non specific binding of couterions. 17 All the mathematical models presented in the literature so far [18][19][20][21][22][23][24][25] cannot deal with all those parameters, sometimes employing empirical equations and bacterial and HA competition. Also the complexation of metals by heterogeneous ligands is dependent on metal loading (the rate of bound metal to the binding site concentration).…”

Section: Moo 3 + H-bonding Ligandmentioning

confidence: 99%

Molybdenum (VI) binded to humic and nitrohumic acid models in aqueous solutions. Salicylic, 3-nitrosalicylic, 5-nitrosalicylic and 3,5 dinitrosalicylic acids: part 2

Lúcia¹,

Mercè²,

Mangrich³

et al. 2006

J. Braz. Chem. Soc.

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Apresentam-se neste trabalho, estudos eletroquímicos e espectroscópicos na região do Ultravioleta-Visível de modelos derivados do ácido salicílico de ácidos húmicos e nitrohúmicos, esse último um artefato laboratorial, na presença de molibdênio para determinar a afinidade desses modelos com esse íon metálico. Molibdênio tem um papel importante na química de solo e conjuntamente com as substâncias húmicas, promove fertilidade ao solo e água e é um elemento chave na enzima nitrogenase. Os resultados obtidos mostraram que pelo menos uma espécie complexada está presente na faixa de pH 6,3 a 8,0, mesmo para o modelo menos básico escolhido, dos ácidos nitrossalicílicos. Estudo anterior mostrou que modelos derivados do ácido ftálico e nitroftálico, modelos também para os ácidos húmicos e nitrohúmicos, apresentaram espécies complexadas apenas até pH 6,5. As constantes de formação calculadas mostraram que a substituição do grupamento nitro na posição orto desfavorece a complexação, quando comparada à substitução para, devido provavelmente ao impedimento estérico no primeiro caso, uma vez que esse impedimento se manifesta indubitavelmente no composto duplamente substituído com o grupamento nitro. Os espectros obtidos por voltametria cíclica e por espectroscopia no Ultravioleta-Visível mostraram que a química do molibdênio em solução aquosa é muito complexa com a variação do pH, e que o ânion molibdato deixa de ser um ânion em valores de pH próximos a 4, quando então passa a se comportar como cátion, MoO 2 2+ (M).In this work electrochemical and Ultraviolet-Visible studies were performed in solutions of salicylic acid models of humic and nitrohumic acids, a laboratory artifact, and molybdenum in order to determine the affinity of these models towards the metal ion. Molybdenum, which plays a very important role in the soil chemistry, and together with humic substances, impart fertility to soil and water and is a key element in the activity of nitrogenase. The obtained results showed that at least one complexed species is present at the pH range of 6.3 to 8.0, even for the less basic chosen models, the nitrosalicylic acids. Previous study showed that phthalic and nitrophthalic, also humic and nitrohumic acids model compounds, presented complexed species with molybdenum only till pH 6.5. The calculated formation constants showed that the substitution of the nitro group in the orto position was less favoured than in the para substitution, probably due to a steric hindrance in the former, which was clearly seen in the double substituted salicylic nitro derivative. The cyclic voltammetry as well as the Ultraviolet-Visible obtained spectra were able to show that the chemistry of molybdenum in aqueous solutions as the pH is increased is very complex, and the molybdate stops acting as an anion only after pH around 4, when it finally becomes a cation MoO 2 2+ (M).

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Kinetic studies of nickel speciation in model solutions of a well-characterized humic acid using the competing ligand exchange method

Cited by 42 publications

References 28 publications

Voltammetric evaluation of binding abilities of tannery effluents by competing ligand exchange method using model solutions of Cr(VI), Ni(II), Cu(II) and Pb(II)

Voltammetric evaluation of binding abilities of tannery effluents by competing ligand exchange method using model solutions of Cr(VI), Ni(II), Cu(II) and Pb(II)

Calcium and sodium as regulators of the recovery of four Daphnia species along a gradient of metal and base cations in metal contaminated lakes in Sudbury, Ontario, Canada

Molybdenum (VI) binded to humic and nitrohumic acid models in aqueous solutions. Salicylic, 3-nitrosalicylic, 5-nitrosalicylic and 3,5 dinitrosalicylic acids: part 2

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