Fe(III)–humate complexes from Megalopolis peaty lignite: A novel eco-friendly fertilizer

Chassapis, Konstantinos; Roulia, Maria; Nika, Georgia

doi:10.1016/j.fuel.2009.10.005

Cited by 25 publications

(13 citation statements)

References 25 publications

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“…One reason can infer that Fe(III) can bind to the carboxylate groups of the substrates and by forming a complex which have a catalytic effect upon phenolic compounds polymerization would increase the reactivity of the substrates towards chlorination. In addition, addition of Fe(III) is also expected to increase the aggregate size of the humic substances as observed in the case of Mg(II) and Ca(II) addition due to intermolecular associations induced by the metal ions present, it will prompt the DBPs formation [23]. According to previous investigations, the total irons in finished water were usually in range of 0.3-0.5 mg/L [24].…”

Section: Resultsmentioning

confidence: 94%

Notice of Retraction: Seasonal Variation of Disinfection By-Products Formation in during Chlorination of Treated Water from Yangtze River: Implication for Human Exposure

Liu

Zhu

Fan

et al. 2011

2011 5th International Conference on Bioinformatics and Biomedical Engineering

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Abstract-In this study, the effect of seasonal variation and Fe(III) concentrations on the formation and distribution of trihalomethanes (THMs) and haloacetic acids (HAAs) during chlorination of treated water samples from Yangzte River were examined. The corresponding lifetime cancer risk of THMs and HAAs was also estimated using the parameters and procedure issued by US Environmental Protection Agency. The results indicated that the mean concentration of THMs (mean, 108.1 μg/L) are significantly higher than that of other seasons, which is related to high bromide ion in raw water during the salt intrusion, and while five HAA5 concentrations were higher in autumn (mean, 25.0 μg/L) than those of other seasons. At the same time, in presence of Fe(III) increase THMs and HAA5 levels. Total cancer risk in spring (1.16×10 -4 ) increased about 2 times than those of summer (5.36×10 -5 ) in our experimental conditions. In addition, in the presence 0.5 mg/L Fe(III), cancer risk increased 10% in spring than those in the absence of Fe(III) under the same conditions. Results showed that the lifetime cancer risk for THMs and HAAs followed the order, oral, inhalation, and dermal. Thus, the seasonal and Fe(III) effects need to be considered in human health risk assessment studies, especially in the area of coastland and estuary area.

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Section: Resultsmentioning

confidence: 94%

Notice of Retraction: Seasonal Variation of Disinfection By-Products Formation in during Chlorination of Treated Water from Yangtze River: Implication for Human Exposure

Liu

Zhu

Fan

et al. 2011

2011 5th International Conference on Bioinformatics and Biomedical Engineering

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“…This result at pH 7 can be related to the high degree of dissociation of acidic functional groups responsible for complexation [ 21 ] and reduced quantity of H + ions that would otherwise compete for adsorption sites. Electrostatic repulsion forces between these ionized groups energetically favor a more expanded molecular configuration, thus making binding sites readily accessible to the metal ions [ 34 ]. All the above interpretations have been confirmed by the values of the complexation capacities (C L ) and stability constants of HA-Zn(II) complexes (logK) calculated from the model ( Table 3 ).…”

Section: Resultsmentioning

confidence: 99%

“…Intensity of this band increases with Zn concentration for HA2, HA4 and HA1 (only at pH 7) and initially decreases and then increases with Zn amount for the HA3, HA5, HA1 (only at pH 5). A drop of absorption of this band at low Zn amounts can result from binding of the metal by OH groups [ 34 ], while an increase from the presence of hydration water and production of aqua-complexes [ 5 ]. An increase in Zn concentration shifts maximum of the band towards higher frequencies, indicating a change in the coordination sphere of the complex.…”

Section: Resultsmentioning

confidence: 99%

Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties

2016

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The main aim of this study was the analysis of the interaction between humic acids (HAs) from different soils and Zn(II) ions at wide concentration ranges and at two different pHs, 5 and 7, by using fluorescence and FTIR spectroscopy, as well as potentiometric measurements. The presence of a few areas of HAs structures responsible for Zn(II) complexing was revealed. Complexation at α-sites (low humified structures of low-molecular weight and aromatic polycondensation) and β-sites (weakly humified structures) was stronger at pH 7 than 5. This trend was not observed for γ-sites (structures with linearly-condensed aromatic rings, unsaturated bonds and large molecular weight). The amount of metal complexed at pH5 and 7 by α and γ-structures increased with a decrease in humification and aromaticity of HAs, contrary to β-areas where complexation increased with increasing content of carboxylic groups. The stability of complexes was higher at pH 7 and was the highest for γ-structures. At pH 5, stability decreased with C/N increase for α-areas and -COOH content increase for β-sites; stability increased with humification decrease for γ-structures. The stability of complexes at α and β-areas at pH 7 decreased with a drop in HAs humification. FTIR spectra at pH 5 revealed that the most-humified HAs tended to cause bidentate bridging coordination, while in the case of the least-humified HAs, Zn caused bidentate bridging coordination at low Zn additions and bidentate chelation at the highest Zn concentrations. Low Zn doses at pH 7 caused formation of unidentate complexes while higher Zn doses caused bidentate bridging. Such processes were noticed for HAs characterized by high oxidation degree and high oxygen functional group content; where these were low, HAs displayed bidentate bridging or even bidentate chelation. To summarize, the above studies have showed significant impact of Zn concentration, pH and some properties of HAs on complexation reactions of humic acids with zinc.

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“…However, an interesting fact is the release of a higher number of H + at pH 5 than at pH 4. Probably, a new population of COOH groups become available and visible at pH 5 due to the reconfiguration and spatial development of the structure [80]. Zn(II) binding on the way of proton exchange at pH 7 was very low, which was associated with almost complete dissociation of the functional groups at these conditions [81].…”

Section: Zinc-protons Competitive Interactionsmentioning

confidence: 99%

Zinc Binding to Fulvic acids: Assessing the Impact of pH, Metal Concentrations and Chemical Properties of Fulvic Acids on the Mechanism and Stability of Formed Soluble Complexes

Boguta

Sokołowska

2020

Molecules

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The aim of the study was defined as a complementary analysis of molecular interactions between zinc (Zn) and fulvic acids (FAs) at a broad pH range (3–7), different metal concentrations (0–50 mg dm−3) and chemical properties of FAs and their impact on the Zn binding mechanism, stability, and efficiency. The results showed that the complexation reaction prevailed at pH 6 and 7, whereas protons exchange dominated interactions at pH 3. Stability constant of the complexes increased along with pH (logK increased from ~3.8 to 4.2). Complexation was preferred by less-humidified structures of lower molecular mass containing more oxygen groups. The number of fluorophores available for Zn(II) increased from pH 3 to 7 by ~44%. Depending on the pH, complexation involved a bidentate chelate, monodentate and bidentate bridging mode. Zn(II) binding was insufficiently modeled by the classic Stern–Volmer equation and well described by the double logarithmic equation (R > 0.94) as well as by a modified Stern–Volmer formula assuming the existence of available and unavailable fluorophore populations (R > 0.98). The fluorescence ratio of different fluorophores was proposed as an indicator of the binding affinity of various structures. A positive relationship was found between the fraction of accessible fluorophores and Zn(II) binding at pH 7 determined based on proton release (R = 0.91–0.97). The obtained results can find application in controlling the mobility and bioavailability of Zn in different conditions.

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Fe(III)–humate complexes from Megalopolis peaty lignite: A novel eco-friendly fertilizer

Cited by 25 publications

References 25 publications

Notice of Retraction: Seasonal Variation of Disinfection By-Products Formation in during Chlorination of Treated Water from Yangtze River: Implication for Human Exposure

Notice of Retraction: Seasonal Variation of Disinfection By-Products Formation in during Chlorination of Treated Water from Yangtze River: Implication for Human Exposure

Interactions of Zn(II) Ions with Humic Acids Isolated from Various Type of Soils. Effect of pH, Zn Concentrations and Humic Acids Chemical Properties

Zinc Binding to Fulvic acids: Assessing the Impact of pH, Metal Concentrations and Chemical Properties of Fulvic Acids on the Mechanism and Stability of Formed Soluble Complexes

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