The role or organic matter and ionic composition in determining the surface charge of suspended particles in natural waters

Beckett, Ronald; Le, Ngoc P.

doi:10.1016/0166-6622(90)80185-7

Cited by 137 publications

(65 citation statements)

References 15 publications

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“…3). The increased negative charge of the NF membrane surface in the presence of humic sub- 1997) stances is similar to observations in natural waters where NOM controls the charge characteristics of mineral surfaces [16,42].…”

Section: Membrane Zeta Potential In the Presence Of Calcium Ions And Nomsupporting

confidence: 63%

Fouling of nanofiltration membranes

1998

Membrane Technology

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The role of chemical and physical interactions in natural organic matter (NOM) fouling of nanofiltration membranes is systematically investigated. Results of fouling experiments with three humic acids demonstrate that membrane fouling increases with increasing electrolyte (NaC1) concentration, decreasing solution pH, and addition of divalent cations (Ca2+). At fixed solution ionic strength, the presence of calcium ions, at concentrations typical of those found in natural waters, has a marked effect on membrane fouling. Divalent cations interact specifically with humic carboxyl functional groups and, thus, substantially reduce humic charge and the electrostatic repulsion between humic macromolecules. Reduced NOM interchain repulsion results in increased NOM deposition on the membrane surface and formation of a densely packed fouling layer. In addition to the aforementioned chemical effects, results show that NOM fouling rate increases substantially with increasing initial permeation rate. It is demonstrated that the rate of fouling is controlled by an interplay between permeation drag and electrostatic double layer repulsion; that is, NOM fouling of NF membranes involves interrelationship (coupling) between physical and chemical interactions. The addition of a strong chelating agent (EDTA) to feed water reduces NOM fouling significantly by removing free and NOM-complexed calcium ions. EDTA treatment of NOM-fouled membranes also improves the cleaning efficiency dramatically by disrupting the fouling layer structure through a ligand exchange reaction between EDTA and NOM-calcium complexes.

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Section: Membrane Zeta Potential In the Presence Of Calcium Ions And Nomsupporting

confidence: 63%

Fouling of nanofiltration membranes

1998

Membrane Technology

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“…As expected from the increased carboxylation of the styrene residues on GB microspheres, in purified water and freshwater solutions, GB microspheres had higher mobilities and DG microspheres had lower mobilities than those of T. gondii oocysts. The increased mobilities seen in the presence of DOC have been previously described in the literature for other particles and are attributed to adsorption of humic and fluvic acids onto the surfaces of the particles (3,21).…”

Section: Discussionmentioning

confidence: 83%

Surface Properties of Toxoplasma gondii Oocysts and Surrogate Microspheres

Shapiro

Largier

Mazet

et al. 2009

Appl Environ Microbiol

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The physical properties that govern the waterborne transmission of Toxoplasma gondii oocysts from land to sea were evaluated and compared to the properties of carboxylated microspheres, which could serve as surrogates for T. gondii oocysts in transport and water treatment studies. The electrophoretic mobilities of T. gondii oocysts, lightly carboxylated Dragon Green microspheres, and heavily carboxylated Glacial Blue microspheres were determined in ultrapure water, artificial freshwater with and without dissolved organic carbon, artificial estuarine water, and artificial seawater. The surface wettabilities of oocysts and microspheres were determined using a water contact angle approach. Toxoplasma gondii oocysts and microspheres were negatively charged in freshwater solutions, but their charges were neutralized in estuarine water and seawater. Oocysts, Glacial Blue microspheres, and unwashed Dragon Green microspheres had low contact angles, indicating that they were hydrophilic; however, once washed, Dragon Green microspheres became markedly hydrophobic. The hydrophilic nature and negative charge of T. gondii oocysts in freshwater could facilitate widespread contamination of waterways. The loss of charge observed in saline waters may lead to flocculation and subsequent accumulation of T. gondii oocysts in locations where freshwater and marine water mix, indicating a high risk of exposure for humans and wildlife in estuarine habitats with this zoonotic pathogen. While microspheres did not have surface properties identical to those of T. gondii, similar properties shared between each microsphere type and oocysts suggest that their joint application in transport and fate studies could provide a range of transport potentials in which oocysts are likely to behave.

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“…Below pH 7, the results can be interpreted in terms of surface considerations. In the presence of LHA, the surface charge of goethite is reversed and becomes negative thus favouring the sorption of cations [2,19,22]. Above pH 7, the soluble LHA forms non-sorbing complexes with Co(II) so that a competition exists for cobalt ions between sorption and complexation by LHA in solution.…”

Section: Effect Of Lha On Sorption Of Co(ii) On Goethitementioning

confidence: 95%

“…Association with solids is greatly influenced by the presence of natural organic matter. Indeed, when adsorbed on the surface of minerals, natural organic matter modifies the physicochemical (e.g., electrophoretic mobility, colloidal stability, and transport) and surface properties of these solids, while in solution it forms complexes with the pollutant metal ions thereby decreasing their adsorption [2,6,19,22].…”

Section: Introductionmentioning

confidence: 99%

Influence of humic acid on sorption of Co(II), Sr(II), and Se(IV) on goethite

et al. 2000

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-This work examined the influence of a leonardite humic acid on the sorption of Co(II), Sr(II), and Se(IV) onto goethite as a function of pH. The sorption of humic acid and ions alone was first studied. The humic acid sorbs appreciably to the goethite surface according to a reversible process, with a maximum sorption of 19 mg of total organic carbon per g of goethite reached at lower pH values (≈ 5). Cobalt and selenium are significantly sorbed on goethite while strontium is only weakly sorbed. In the presence of humic acid, the cobalt sorption is enhanced in acidic media due to the humic acid sorption on goethite, which modified the surface properties by making it more negative. However, it decreases in alkaline media due to the complexation of Co(II) by soluble humic acid. The sorption of Sr(II) is significantly increased in the presence of humic acid even in alkaline media. The sorption of selenite ions (SeO 3 2-) decreases in the presence of humic acid because a competition with humate ions occurs at the surface sites of the goethite. The results presented here constitute a good set of data for modelling the effect of humic acid on the sorption of ions on goethite.sorption / humic acid / goethite / cobalt / strontium / selenium Résumé -Influence de l'acide humique sur la sorption de Co(II), Sr(II) et Se(IV) sur une goethite. Dans ce travail est examinée l'influence de l'acide humique leonardite sur la sorption de Co(II), Sr(II) et Se(IV) sur une goethite en fonction du pH. La sorption de l'acide humique et de chaque ion a été étudiée séparément en premier lieu. L'acide humique est sorbé de façon non négligeable sur la goethite, selon un mécanisme réversible, avec un maximum sorbé de 19 mg de carbone organique total par g de goethite observé aux valeurs de pH les plus faibles (pH ≈ 5). Le cobalt et le sélénium présentent une bonne aptitude à se sorber sur la goethite tandis que le strontium n'est que faiblement retenu. En présence d'acide humique, la sorption de Co(II) est favorisée en milieu acide car la sorption de l'acide humique sur la goethite rend la surface du minéral plus négative. En milieu basique, au contraire, la sorption est diminuée en raison de la complexation des ions cobalt par l'acide humique soluble. La sorption de Sr(II) augmente en présence d'acide humique, Agronomie 20 (2000) [525][526][527][528][529][530][531][532][533][534][535] 525

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The role or organic matter and ionic composition in determining the surface charge of suspended particles in natural waters

Cited by 137 publications

References 15 publications

Fouling of nanofiltration membranes

Fouling of nanofiltration membranes

Surface Properties of Toxoplasma gondii Oocysts and Surrogate Microspheres

Influence of humic acid on sorption of Co(II), Sr(II), and Se(IV) on goethite

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