Association and colloid-chemical properties of humic acids in aqueous solutions

Tarasevich, Yu. I.; Доленко, С. А.; Trifonova, M. Yu.; Alekseenko, E. Yu.

doi:10.1134/s1061933x13020166

Cited by 24 publications

(28 citation statements)

References 22 publications

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“…The hydrodynamic diameters at peak maxima were calculated to be 1.7 nm for A-1.1 mg/L and 160 µm for E-20.0 mg/mL. The inversion point observed (reversal of retention order between Aldrich HA and PSS (MW = 5400 Da) at approximately 5 mg/mL (5 g·L −1 ) of Aldrich HA by flow FFF at low ionic strength corresponds with its reported critical micelle concentration determined by other methods: 7.4 g·L −1[9], and that of other HAs as 4 mg·mL −1 (4·g L −1 ) [10], 0.5%-0.6% (5-6 g·L −1 )[11], and 8 g·dm −3 (8 g·L −1 )[12].…”

supporting

confidence: 78%

“…NOM was considered to be a continuum of hydrodynamic diameters by Beckett and Ranville [18]. Tarasevich et al [12] reported that, at low concentrations, HAs exist as individual molecules; as the concentration is increased, they associate to form supramolecular structures at 5 mg·dm −3 (5 mg·L −1 ) and micelles at 8 g·dm −3 (8 g·L −1 ). Representative components of the different size ranges probably all dynamically coexist in solution.…”

Section: Integrating the Datamentioning

confidence: 99%

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Conductivity-Dependent Flow Field-Flow Fractionation of Fulvic and Humic Acid Aggregates

Wells

2015

Chromatography

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Fulvic (FAs) and humic acids (HAs) are chemically fascinating. In water, they have a strong propensity to aggregate, but this research reveals that tendency is regulated by ionic strength. In the environment, conductivity extremes occur naturally-freshwater to seawater-warranting consideration at low and high values. The flow field flow fractionation (flow FFF) of FAs and HAs is observed to be concentration dependent in low ionic strength solutions whereas the corresponding flow FFF fractograms in high ionic strength solutions are concentration independent. Dynamic light scattering (DLS) also reveals insight into the conductivity-dependent behavior of humic substances (HSs). Four particle size ranges for FAs and humic acid aggregates are examined: (1) <10 nm; (2) 10 nm-6 µm; (3) 6-100 µm; and (4) >100 µm. Representative components of the different size ranges are observed to dynamically coexist in solution. The character of the various aggregates observed-such as random-extended-coiled macromolecules, hydrogels, supramolecular, and micellar-as influenced by electrolytic conductivity, is discussed. The disaggregation/aggregation of HSs is proposed to be a dynamic equilibrium process for which the rate of aggregate formation is controlled by the electrolytic conductivity of the solution.

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supporting

confidence: 78%

Section: Integrating the Datamentioning

confidence: 99%

Conductivity-Dependent Flow Field-Flow Fractionation of Fulvic and Humic Acid Aggregates

Wells

2015

Chromatography

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“…The structure of humic acids is very dynamic and sensitive to circumstances such as concentration, pH and ionic strength [24,45,46]. They can be characterized by a supramolecular arrangement of relatively small particles in co-existence with bigger macromolecules [24,[45][46][47][48][49][50][51], which makes it possible to respond to changes in their surroundings.…”

Section: Resultsmentioning

confidence: 99%

Agarose Hydrogels Enriched by Humic Acids as the Complexation Agent

Klučáková

2020

Polymers

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The transport properties of agarose hydrogels enriched by humic acids were studied. Methylene blue, rhodamine 6G and Cu(II) ions were incorporated into hydrogel as diffusion probes, and then their release into water was monitored. Cu(II) ions as well as both the dyes studied in this work have high affinity to humic substances and their interactions strongly affected their diffusion in hydrogels. It was confirmed that humic acids retarded the transport of diffusion probes. Humic acids’ enrichment caused the decrease in the values of effective diffusion coefficients due to their complexation with diffusion probes. In general, the diffusion of dyes was more affected by the complexation with humic acids in comparison with Cu(II) ions. The effect of complexation was selective for the particular diffusion probe. The strongest effect was obtained for the diffusion of methylene blue. It was assumed that metal ions interacted preferentially with acidic functional groups. In contrast to Cu(II) ions, dyes can interact with acidic functional groups, and the condensed cyclic structures of the dye probes supported their interactions with the hydrophobic domains of humic substances.

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“…Copper ions in the test sheets are bound to the functional groups of the humate chains in chelated form . Additional humate molecules bind to copper ions bound to humate forming the micelle structure of humate . Copper ions bound by the chelate bond may soon be released in aqueous medium, thus diffusing into the agar.…”

Section: Resultsmentioning

confidence: 99%

“…29,54,84,85 Additional humate molecules bind to copper ions bound to humate forming the micelle structure of humate. [86][87][88] Copper ions bound by the chelate bond may soon be released in aqueous medium, thus diffusing into the agar. Preincubation of the prepared uninoculated plates proved to be crucial;…”

Section: Antimicrobial Activitymentioning

confidence: 99%

Antimicrobial activity of copper‐humate‐cellulose sheets

2020

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During our research, cellulose‐based test sheets containing copper and potassium humate were prepared and tested against several bacterial and fungal strains. The energy dispersive X‐ray spectrometry and attenuated total reflectance (ATR) Fourier‐transform infrared spectroscopy revealed that humate contributed to increase the copper content of the test sheets. The antimicrobial impact of test sheets on various fungi (Penicillium expansum, Wallemia sebi, and Aspergillus brasiliensis) and bacteria (genera Micrococcus, Enterococcus, Bacillus, Salmonella, Staphylococcus, Listeria genera) was tested using a modified agar diffusion‐based assay. On the basis of the disc diffusion results, the sheets effectively inhibited all the tested fungi and Gram‐positive bacteria. The highest antimicrobial effect was exhibited by the copper‐containing test sheet with 1:0.1 and 1:0.25 cellulose:humate weight ratio. Deterioration test with blackberries demonstrated the shelf life extending effect of the sheets.

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Association and colloid-chemical properties of humic acids in aqueous solutions

Cited by 24 publications

References 22 publications

Conductivity-Dependent Flow Field-Flow Fractionation of Fulvic and Humic Acid Aggregates

Conductivity-Dependent Flow Field-Flow Fractionation of Fulvic and Humic Acid Aggregates

Agarose Hydrogels Enriched by Humic Acids as the Complexation Agent

Antimicrobial activity of copper‐humate‐cellulose sheets

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