Aggregation of montmorillonite and organic matter in aqueous media containing artificial seawater

Yoko Furukawa, Janet L. Watkins, Jin-Wook Kim, Kenneth J. Curry, Richard H. Bennett

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Background: The dispersion-aggregation behaviors of suspended colloids in rivers and estuaries are affected by the compositions of suspended materials (i.e., clay minerals vs. organic macromolecules) and salinity. Laboratory experiments were conducted to investigate the dispersion and aggregation mechanisms of suspended particles under simulated river and estuarine conditions. The average hydrodynamic diameters of suspended particles (representing degree of aggregation) and zeta potential (representing the electrokinetic properties of suspended colloids and aggregates) were determined for systems containing suspended montmorillonite, humic acid, and/or chitin at the circumneutral pH over a range of salinity (0-7.2 psu). Results: The montmorillonite-only system increased the degree of aggregation with salinity increase, as would be expected for suspended colloids whose dispersion-aggregation behavior is largely controlled by the surface electrostatic properties and van der Waals forces. When montmorillonite is combined with humic acid or chitin, the aggregation of montmorillonite was effectively inhibited. The surface interaction energy model calculations reveal that the steric repulsion, rather than the increase in electronegativity, is the primary cause for the inhibition of aggregation by the addition of humic acid or chitin. Conclusion: These results help explain the range of dispersion-aggregation behaviors observed in natural river and estuarine systems. It is postulated that the composition of suspended particles, specifically the availability of steric polymers such as those contained in humic acid, determine whether the river suspension is rapidly aggregated and settled or remains dispersed in suspension when it encounters increasingly saline environments of estuaries and oceans.

Original languageEnglish
Article number2
JournalGeochemical Transactions
Volume10
DOIs
Publication statusPublished - 2009 Jan 23

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Bentonite
Seawater
montmorillonite
Biological materials
aggregation behavior
Agglomeration
humic acid
chitin
seawater
Humic Substances
organic matter
colloid
Chitin
Colloids
salinity
river
Rivers
estuary
Estuaries
Suspensions

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology

Cite this

Furukawa, Yoko ; Watkins, Janet L. ; Kim, Jin-Wook ; Curry, Kenneth J. ; Bennett, Richard H. / Aggregation of montmorillonite and organic matter in aqueous media containing artificial seawater. In: Geochemical Transactions. 2009 ; Vol. 10.
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Aggregation of montmorillonite and organic matter in aqueous media containing artificial seawater. / Furukawa, Yoko; Watkins, Janet L.; Kim, Jin-Wook; Curry, Kenneth J.; Bennett, Richard H.

In: Geochemical Transactions, Vol. 10, 2, 23.01.2009.

Research output: Contribution to journalArticle

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