Aggregation of humic acid in solution: Contributions of different fractions

Chilom, Gabriela; Bruns, Angela S.; Rice, James A.

doi:10.1016/j.orggeochem.2009.01.010

Cited by 53 publications

(45 citation statements)

References 34 publications

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“…Three procedures for chemical modification were performed on LAHA: acid hydrolysis,[44] Soxhlet lipid extraction[45] and bleaching. [46]…”

Section: Methodsmentioning

confidence: 99%

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Deese¹,

LeBlanc²,

Cook³

2016

Environ. Chem.

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Surfactants can be extremely toxic to aquatic species and are introduced to the environment in a variety of ways. It is thus important to understand how other environmental constituents, in this case humic acids (HAs), may alter the toxicity of anthropogenic surfactants. Hatching and mortality assays of Artemia Franciscana were performed for three different toxic surfactants: Triton X-100 (Tx-100, non-ionic), cetylpyridinium chloride (CPC, cationic), and sodium dodecyl sulfate (SDS, anionic). Humic acids of varying composition and concentrations were added to the assays to determine the toxicity mitigating ability of the HAs. Tx-100 had a significant toxic effect on Artemia mortality rates and HAs from terrestrial sources were able to mitigate the toxicity, but an aquatic HA did not. CPC and SDS limited hatching success of the Artemia and, as HAs were added, the hatching percentages increased for all HA sources, indicating toxicity mitigation. In order to determine which functional groups within HAs were responsible for the interaction with the surfactants, the HAs were chemically modified by: (i) bleaching to reduce aromatics, (ii) Soxhlet extraction to reduce lipids, and (iii) acid hydrolysis to reduce O- and N-alkyl groups. Although most of the modified HAs had some toxicity mitigating ability for each of the surfactants, there were two notable differences: 1) the lipid-extracted HA did not reduce the toxicity of Tx-100 and 2) the bleached HA had a lower toxicity mitigating ability for CPC than the other modified HAs.

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“…Three procedures for chemical modification were performed on LAHA: acid hydrolysis,[44] Soxhlet lipid extraction[45] and bleaching. [46]…”

Section: Methodsmentioning

confidence: 99%

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Deese¹,

LeBlanc²,

Cook³

2016

Environ. Chem.

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“…Numerous studies have shown that the extent and type of HA aggregation depends on HA components, pH, ionic strength, type of electrolyte, and temperature (Palmer and von Wandruszka 2001;Terashima et al 2004;Chilom et al 2009;Wang et al 2013). The obtained values of the CQ internal oxidation acc.…”

Section: Resultsmentioning

confidence: 89%

“…Humic acids have an amphiphilic nature, that is why they spontaneously form micelle-like structures in aquatic solutions, which are rather a variety of species of different molecular size (Palmer and von Wandruszka 2001;Chilom et al 2009). Numerous studies have shown that the extent and type of HA aggregation depends on HA components, pH, ionic strength, type of electrolyte, and temperature (Palmer and von Wandruszka 2001;Terashima et al 2004;Chilom et al 2009;Wang et al 2013).…”

Section: Resultsmentioning

confidence: 99%

Studying of the interaction between peat humic acids and metazachlor using spectroscopy methods

et al. 2018

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Purpose The analysis covered the interaction of humic acids (HA) isolated from peats with the metazachlor using spectroscopic methods. Materials and methods Five peatlands have been selected for the study in the southern and northern parts of Poland. Extraction of humic acids (HA1, HA2, HA3, HA4, and HA5) was performed using a procedure recommended by the International Humic Substances Society. Metazachlor 500 SC with metazachlor as a biologically active substance [2-chloro-N-(pyrazol-1-ylmethyl)acet-2′,6′-xylidide] has been used. HA have been assessed on the basis of their elemental composition. Spectroscopic techniques have been used to study the HA structure and their interaction with metazachlor including: UVvisible spectroscopy, dynamic light scattering, and delayed luminescence (DL) Results and discussion Based on their morphological and chemical properties, the studied peat soils can be classified as follows: (1) Eutric Murshic Sapric Histosols, (2) Eutric Sapric Histosols, (3) Eutric Hemic Histosols, (4) Eutric Fibric Histosols, and (5) Dystric Dranic Hemic Histosols according to the WRB guidelines (2015). Results showed that the largest particle size, measured by E 4/6 coefficient, was found in HA2 sample, while the smallest in HA3 sample. The addition of metazachlor to HA solutions reduced the values of E 4/6 coefficient by 33 to 72%, while the values of hydrodynamic diameter by 4 to 32%. No significant changes were found between E 4/6 after adding of metazachlor to HA solutions. The largest changes in DL intensity, excited both by blue and red light after herbicide addition, were observed in HA2 sample, which is characterized by the largest particle size, the highest oxygen content and CQ value as well as the lowest Baromatization rate^value. Conclusions The particle sizes of HA molecules measured by E 4/6 coefficient do not impact on the particle sizes of HA-herbicide systems measured by the same ratio. The delayed luminescence may become valuable, because it is simple, fast, and sensitive. Additionally, the results show minor errors comparing with chemical methods. This method may provide information about structure and nature of humic acids, as well as their photoreactivity. The using of delayed luminescence in studies of HApesticides interaction may enable us to better understand the luminescence properties of HA.

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“…In water solution, surfactants are capable of trapping hydrophobic molecules inside the surfactant micelle-structure and removing them from the soil. Surfactants form micelles at a concentration defined as the critical micelle concentration (cmc) which varies according to the surfactant's chemical characteristics, pH and temperature (Terashima et al, 2004;Chilom et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Chlorpyrifos-methyl solubilisation by humic acids used as bio-surfactants extracted from lignocelluloses and kitchen wastes

et al. 2016

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Aggregation of humic acid in solution: Contributions of different fractions

Cited by 53 publications

References 34 publications

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Surfactant toxicity to Artemia franciscana and the influence of humic acid and chemical composition

Studying of the interaction between peat humic acids and metazachlor using spectroscopy methods

Chlorpyrifos-methyl solubilisation by humic acids used as bio-surfactants extracted from lignocelluloses and kitchen wastes

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