Sorption of copper cations from aqueous solutions by brown coals and humic acids

Жеребцов, С. И.; Малышенко, Н. В.; Bryukhovetskaya, L. V.; Lyrshchikov, S. Yu.; Ismagilov, Z. R.

doi:10.3103/s0361521915050110

Cited by 16 publications

(5 citation statements)

References 8 publications

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“…Most HA used in the literature are extracted from soils, water, sediments, or peat (Chen et al, 2015;Plaza et al, 2005;Zherebtsov et al, 2015). The formation of these environmental elements under natural conditions requires significant amounts of time and involves several chemical and biological reactions that can last for years (Yang et al, 2019a).…”

Section: Introductionmentioning

confidence: 99%

Humic-like acids from hydrochars: Study of the metal complexation properties compared with humic acids from anthropogenic soils using PARAFAC and time-resolved fluorescence

Santos

Fregolente

Moreira

et al. 2020

Science of The Total Environment

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Humic acids (HA) play an important role in the distribution, toxicity, and bioavailability of metals in the environment. Humic-like acids (HLA) that simulate geochemical processes can be prepared by NaOH aqueous extraction from hydrochars produced by hydrothermal carbonization (HTC). HLA can exhibit properties such as those found in HA from soils, which are known for their ability to interact with inorganic and organic compounds. The molecular characteristics of HLA and HA help to explain the relationship between their molecular features and their interaction with metallic species.The aim of this study is to assess the molecular features of HA extracted from Terra Mulata (TM) and HLA from hydrochars as well as their interaction with metals by using Cu(II) ions as a model. The results from 13 C NMR, elemental analysis, FTIR, and UV-Vis showed that HA are composed mostly of aromatic structures and oxygenated functional groups, whereas HLA showed a mutual contribution of aromatic and aliphatic structures as main constituents. The interactions of HA and HLA with Cu(II) ions were evaluated through fluorescence quenching, in which the density of complexing sites per gram of carbon for interaction was higher for HLA than for HA. Furthermore, the HLA showed similar values for stability constants, and higher than those found for other types of HA in the literature. In addition, the average lifetime in both humic extracts appeared to be independent of the copper addition, indicating that the main mechanism of interaction was static quenching with a non-fluorescent groundstate complex formation. Therefore, the HLA showed the ability to interact with Cu(II) ions, which suggests that their application can provide a new approach for remediation of contaminated areas.

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Section: Introductionmentioning

confidence: 99%

Humic-like acids from hydrochars: Study of the metal complexation properties compared with humic acids from anthropogenic soils using PARAFAC and time-resolved fluorescence

Santos

Fregolente

Moreira

et al. 2020

Science of The Total Environment

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“…Moreover, FA tends to aggregate with the formation of complex supramolecular structures, reducing its solubility, stability and activity. The ability to form stable complexes with various metal ions [25][26][27][28][29][30] not only creates new biological activity, but also complicates the FA release from various dosage forms.…”

Section: Introductionmentioning

confidence: 99%

Fulvic acid transdermal patch: Its properties, optimization and release

Konnova,

Volkov,

Melnikova

2024

J. Drug Delivery Ther.

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There is a high demand for the design of fulvic acids (FA) transdermal patches being natural biologically active substances with a wide action. The difficulties in FA transdermal patches creating are due to the peculiarities of FA obtaining with high purity and solubility, the existence of many several polymorphic forms, as well as the problems of their insertion into dosage forms. In this work, we modified the FA isolation as water-soluble polymorph. This operation allowed us to reduce the impurities in the product, to optimize the formulation of the emulsion-based transdermal patches, to provide a quantitative assessment of FA release. Data of IR, 13C NMR, AAS, ICP-AES-spectra, direct and reverse titration of carboxyl groups and phenolic hydroxyls, potentiometry, molecular weight determination by cryoscopy (M.m=740 g/mol), fluorescent analysis, solubility (3.3 mL of water per gram) confirmed the receipt of the desired polymorph. Optimization of the transdermal patches formulations by Response Surface Methodology and release evaluation and kinetics mathematical modeling using a Franz cell showed the preferences of Pluronic Kolliphor p237 as a transcutant. The obtained water-soluble FA can be used as a potential component of transdermal patches with controlled release parameters. Keywords: fulvic acid, transdermal patches, pluronics, release

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“…The presence of electron-donating functional groups in the structure of humic acids (HA), >C ¼ O, -COOH, -C-OH, ArOH, -NH-, -NH 2 , in various combinations and free orbitals of metal cations contributes to the formation of coordination compounds during their interactions [1][2][3][4]. This results in the following mechanisms: ion exchange, complexation with electron donor functional groups; complexation with the formation of a Me nþ -HA bond due to the presence of free p-electrons on the surface.…”

Section: Introductionmentioning

confidence: 99%

“…The interaction of copper cations with humic acids of different origin has been studied [1,10]. As a result of the study, it was shown that the amount of sorption cations of copper depends on the functional and structural composition of humic acids and the pH of the medium and that several mechanisms contribute to the sorption process to varying degrees.…”

Section: Introductionmentioning

confidence: 99%

“…Many researchers state that the complexity of the structure of humic substances causes certain difficulties to study their properties and it is the reason for their ambiguous interpretation. Thus, the researchers make cautious assumptions about the fact of the complex formation of Cu 2þ with humic substances and emphasize that several mechanisms contribute to varying degrees in the process of sorption of copper cations with humic acids [1].…”

Section: Introductionmentioning

confidence: 99%

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Interaction of metal ions with humic acids of brown coals of Kazakhstan

Dauletbay

Serikbayev

Kamysbayev

et al. 2020

Journal of Experimental Nanoscience

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This paper investigates interaction processes of the Fe 3þ , Cu 2þ , Ni 2þ , and Co 2þ cations with humic acids isolated from brown coals of Ekibastuz basin. It was demonstrated that the sorption of heavy metal ions by humic acids (HA) depends on the concentration and nature of cations and decreases in the order of Fe 3þ > Cu 2þ > Ni 2þ > Co 2þ ; while increase in the concentration of humic acids (HA) results in the higher yield of ions and metals. The occurrence of ion exchange and complexation reactions in metal-humic acid systems is confirmed by the appearance of new bands and the shift of the absorption bands corresponding to stretching and deformation vibrations of carboxylate ions, C ¼ O and OH groups. The occurrence of these processes is also evidenced by spectrophotometric data, as well as a decrease in the pH of the solution due to deprotonation of humic acids during these reactions. Thus, based on the data on the degree of sorption of metal cations by humic acids, the results of infra-red spectroscopy and spectrophotometry, it can be concluded that the Fe 3þ , Ni 2þ , Co 2þ , Cu 2þ cations interact with HA by the ionic mechanism and by the complexation mechanism with electrondonating functional groups. Electrochemical studies of the Cu 2þhumic acid system carried out by the method of cyclic voltammetry also indicate the occurrence of the interaction of humic acid with copper cations. Modification of humic acid with copper ions shows the electrochemical activity of copper immobilized on the surface of dispersed humic acid, which is important for the implementation of electrocatalytic reactions on modified glassy carbonhumic electrodes.

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Sorption of copper cations from aqueous solutions by brown coals and humic acids

Cited by 16 publications

References 8 publications

Humic-like acids from hydrochars: Study of the metal complexation properties compared with humic acids from anthropogenic soils using PARAFAC and time-resolved fluorescence

Humic-like acids from hydrochars: Study of the metal complexation properties compared with humic acids from anthropogenic soils using PARAFAC and time-resolved fluorescence

Fulvic acid transdermal patch: Its properties, optimization and release

Interaction of metal ions with humic acids of brown coals of Kazakhstan

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