Competitive complexation of metal ions with humic substances

Zhou, Ping; Yan, Hui; Gu, Baohua

doi:10.1016/j.chemosphere.2004.10.017

Cited by 123 publications

(69 citation statements)

References 30 publications

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“…Humic acids, when present, will react with both the iron and iron hydroxides [150][151][152][153][154][155][156]. No ZVI desalination trials have been undertaken to date on saline water containing high concentrations of humic or carboxylic acids.…”

Section: I3 Humic Acids and Microbiotamentioning

confidence: 99%

ZVI (Fe0) Desalination: Stability of Product Water

Antia¹

2016

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A batch-operated ZVI (zero valent iron) desalination reactor will be able to partially desalinate water. This water can be stored in an impoundment, reservoir or tank, prior to use for irrigation. Commercial development of this technology requires assurance that the partially-desalinated product water will not resalinate, while it is in storage. This study has used direct ion analyses to confirm that the product water from a gas-pressured ZVI desalination reactor maintains a stable salinity in storage over a period of 1-2.5 years. Two-point-three-litre samples of the feed water (2-10.68 g (Na + + Cl´)¨L´1) and product water (0.1-5.02 g (Na + + Cl´)¨L´1) from 21 trials were placed in storage at ambient (non-isothermal) temperatures (which fluctuated between´10 and 25˝C), for a period of 1-2.5 years. The ion concentrations (Na + and Cl´) of the stored feed water and product water were then reanalysed. The ion analyses of the stored water samples demonstrated: (i) that the product water salinity (Na + and Cl´) remains unchanged in storage; and (ii) the Na:Cl molar ratios can be lower in the product water than the feed water. The significance of the results is discussed in terms of the various potential desalination routes. These trial data are supplemented with the results from 122 trials to demonstrate that: (i) reactivity does not decline with successive batches; (ii) the process is catalytic; and (iii) the process involves a number of steps.

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Section: I3 Humic Acids and Microbiotamentioning

confidence: 99%

ZVI (Fe0) Desalination: Stability of Product Water

Antia¹

2016

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“…In humic acid-containing binary mixture solutions of Cu(II) and Cd(II), it was shown that the presence of Cd(II) did not significantly affect Cu(II) sorption whereas Cd(II) sorption severely decreased when Cu(II) was present [19]. Zhou et al [20] showed for Ni(II)-Ca(II)-Al(III)-humic acid (HL) system that Ni adsorption on HL increased in concentrated humate solutions at high pH due to the formation of Ni-HL complexes, but Ni-HL complexation was significantly inhibited at high concentrations of Ca 21 ; when pH and HL concentrations were increased, the inhibitive effect of Ca was less. Faur-Brasquet et al investigated the sorption of Cu(II) and Pb(II) from single metal solution on three types of activated carbon, and additionally tested binary sorption of Cu(II)-Pb(II) on the same substrates from benzoic acid solution.…”

mentioning

confidence: 98%

Modeling competitive adsorption of copper(II), lead(II), and cadmium(II) by kaolinite‐based clay mineral/humic acid system

Hızal

Apak

Hoell

2009

Env Prog and Sustain Energy

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The aim of this work is to investigate and model the simultaneous adsorption of Cu(II), Cd(II), and Pb(II) in the presence and absence of humic acid on kaolinite-based clays. The preliminary capacity estimation of clays for metal was made with the use of a modified Langmuir approach, and adsorption data collected at various pH were processed using the FITEQL 3.2 computer program to establish the model. The three types of surface sites responsible for adsorption were considered to be the permanent charge sites X 2 22 , and variable charge sites comprised of BS 1 OH silanol groups and BS 2 OH aluminol groups of kaolinite-based clays. Heavy metal cations were assumed to bind to the surface in the form of outer sphere and inner sphere monodentate complexes. When humic acid was added, divalent metal ion adsorption was modeled using a multisite binding model by the aid of FITEQL 3.2. Since the stability of the ternary surface complexes in the presence of humic acid was higher than that of the corresponding binary heavy metal cation complexes, the adsorption versus pH curves were steeper (and distinctly S-shaped) compared with the tailed curves observed in binary claymetal ion systems, probably due to the fact that humic acid-coated kaolinite essentially constituted the active surface for metal sorption. Although competitive metal adsorption from (metal ions mixture1humate) solutions was generally lower than those from individual metal ion solutions, Cd 21 , being the metal ion with the highest affinity toward permanent charge sites, was the least affected ion at relatively low pH from competitive adsorption. Prog, 28: 493-506, 2009 Keywords: heavy metals, competitive adsorption, clay, FITEQL, adsorption modeling INTRODUCTION Cadmium(II), lead(II), and copper(II) are wellknown toxic heavy metals, which pose a serious threat to the fauna and flora of receiving water bodies when discharged into industrial wastewater. In spite of strict regulations restricting their careless disposal, these metal cations may still emerge in a variety of wastewaters stemming from catalyst, painting and coating, extractive metallurgy, antibacterials, insecticides and fungicides, photography, metal electroplating, fertilizer, mining, pigments, stabilizers, alloy industries, electrical wiring, plumbing, heating, roofing and building construction, piping, water purification, gasoline additive, and battery industries [1,2]. The acute toxicity of these heavy metals has caused various ecological catastrophes in human history such as the ''itai-itai'' disease due to cadmium [3]. Prolonged effect may cause other chronical disorders [4]. Various methods such as hydrometalurgical technologies, ion exchange, electrodialysis, reverse osmosis, precipitation, and adsorption have been used for heavy metal removal from environmental aqueous solution [5]. Heavy metal adsorption on soils and soil minerals has been the subject of many studies during the last decade [6,7]. American Institute of Chemical Engineers EnvironClays readily adsorb heavy metal ions...

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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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Competitive complexation of metal ions with humic substances

Cited by 123 publications

References 30 publications

ZVI (Fe0) Desalination: Stability of Product Water

ZVI (Fe0) Desalination: Stability of Product Water

Modeling competitive adsorption of copper(II), lead(II), and cadmium(II) by kaolinite‐based clay mineral/humic acid system

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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