Alteration of the molecular-size-distribution of Boom Clay dissolved organic matter induced by Na+ and Ca2+

Durce, Delphine; Maes, N.; Bruggeman, Christophe; Ravestyn, L. Van

doi:10.1016/j.jconhyd.2015.12.001

Cited by 20 publications

(9 citation statements)

References 43 publications

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“…The structure of humic and fulvic acids is dynamic with regard to environmental conditions. The concentration, pH, ionic strength, and nature of the counter-ion influence the size and shape of the dissolved organic species (Durce et al, 2016 ). However, many fundamental questions relating, in particular, to the physicochemical characteristics of humic and fulvic molecules are yet to be answered (Klučáková, 2016 ; Tarasevich et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

Size and Charge Evaluation of Standard Humic and Fulvic Acids as Crucial Factors to Determine Their Environmental Behavior and Impact

Klučáková

2018

Front. Chem.

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In this work, the size and charge of humic and fulvic standards purchased from the International Humic Substances Society are presented and discussed. The secondary structure of humic substances in water environment as well as the size and shape of the dissolved humic species and their changes are ill-defined, very dynamic and can be strongly affected by environmental conditions as the concentration, pH, and ionic strength. They have a strong propensity to aggregate which control their interactions with other components, mobility, and functioning in the environment. Particle size distributions were determined by means of dynamic light scattering, zeta potential by Doppler electrophoresis. The intensity, volume, and number particle size distribution were obtained. Two or three different size fractions were detected in the studied systems. Large macroparticles (>1 μm) were observed in the majority of them, mainly in the case of more concentrated solutions. Medium fractions of fulvic submicroparticles had higher average diameters (500–1,200 nm) than those in humic acids (300–600 nm). Small nanoparticles (<100 nm) were detected mainly in alkaline solutions. Fulvic acids with more functional groups (active sites) can form more easily bigger particles mainly in medium concentration region. Alkaline conditions supported the expansion of humic and fulvic coils and liberation of small particles from them. The colloidal stability, indicated by more negative zeta potentials, was higher for humic acids. In the case of fulvic acids, the colloidal stability increased with increasing pH as a result of the dissociation of their functional groups. The increase of particle size corresponded usually with higher stability.

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Section: Introductionmentioning

confidence: 99%

Size and Charge Evaluation of Standard Humic and Fulvic Acids as Crucial Factors to Determine Their Environmental Behavior and Impact

Klučáková

2018

Front. Chem.

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“…At neutral and alkaline pH's, it was observed that the OC <0.45µm curve differed from the others indicating a large proportion of molecules with a molecular size higher than 30 kDa. The pH-dependent molecular size of organic compounds released from the 14-year SD can be simplified by grouping the results within different molecular size classes [14,60]. The size of the leached organic compounds was therefore described here in a simplified manner according to the following classes: (i)…”

Section: Assessment Of the Molecular Size Of Emitted Organics Compound At Various Ph From Sdmentioning

confidence: 99%

“…[25] on the 7-year SD sample could explain the significant increase in conductivity observed under acidic conditions for the 14-year SD. This phenomenon occurring with the acidification of the solutions may promote the aggregation of large macromolecules (>20 kDa) into solid OM >0.45 µm [14,64].…”

Section: Assessment Of the Molecular Size Of Emitted Organics Compound At Various Ph From Sdmentioning

confidence: 99%

“…The release of DOM from SOM may occur by different mechanisms, such as the hydrolysis of macromolecular structures [14,15] or the desorption of organic molecules attached to solid mineral phases [16,17]. The extent to which each mechanism may contribute to the overall leaching phenomenon is dictated by the physico-chemical characteristics of the solid matter of origin [18] and the environmental conditions of the medium.…”

Section: Introductionmentioning

confidence: 99%

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Influence of pH on the release of colloidal and dissolved organic matter from vertical flow constructed wetland surface sludge deposits

Banc¹,

Gautier²,

Blanc³

et al. 2021

Chemical Engineering Journal

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“…The complex structure of HA is dynamic depending on environmental conditions such as pH or ionic strength, which determine the mobility of certain contaminants and trace metals. HA contains different size fractions with different mobility that affects the bioavailability of pollutants in different ways [39,41].…”

Section: Evaluation Of Hg Speciationmentioning

confidence: 99%

Immobilization of mercury in contaminated soils through the use of new carbon foam amendments

Janeiro-Tato

López-Antón

Baragaño

et al. 2021

Preprint

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Background: Mercury (Hg) is recognized as one of the 10 most toxic elements and is much more persistent in soils than in other environmental compartments. However, an effective, environmentally friendly, economical, and applicable at large-scale technology for the remediation of soils contaminated by Hg has not yet been established. This study evaluates the feasibility of a new carbon foam-based product for the remediation of three soils contaminated with Hg, and infers the mobilization or immobilization mechanism through a detailed study of Hg speciation. Results: Soil treatment with the carbon foams, one of them impregnated with goethite, reduced Hg availability by between 75 and 100%. Mercury associated to humic acid (Hg-HA) determined the proportion of mobility and availability of Hg when soils were treated with carbon foams. When the pH dropped, the structure of HA changed causing the Hg-HA to become part of the unavailable fraction of the soil along with HgS. The carbon foam impregnated with goethite did not mobilize Fe as occurred with ZVI nanoparticles. The presence of acid groups on the surface of the foam (carboxyl, quinone and phenolic groups) can bind metal cations strongly improving Fe immobilization. Conclusions: A novel carbon foam-based amendment was efficient in immobilizing Hg in all the soils studied. The carbon foam impregnated with goethite, in addition to not mobilizing Fe, had the additional advantage of its lesser effect on the electrical conductivity of the soil. This novel approach could be considered as a potential amendment for other sites contaminated with Hg and/or other metal(loid)s.

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Alteration of the molecular-size-distribution of Boom Clay dissolved organic matter induced by Na+ and Ca2+

Cited by 20 publications

References 43 publications

Size and Charge Evaluation of Standard Humic and Fulvic Acids as Crucial Factors to Determine Their Environmental Behavior and Impact

Size and Charge Evaluation of Standard Humic and Fulvic Acids as Crucial Factors to Determine Their Environmental Behavior and Impact

Influence of pH on the release of colloidal and dissolved organic matter from vertical flow constructed wetland surface sludge deposits

Immobilization of mercury in contaminated soils through the use of new carbon foam amendments

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