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Determination of Distribution Ratios of Aromatic Compounds between Aqueous Solution and Surfactant-Covered Silica by a Chromatographic Method

Title data

Holzheu, Stefan ; Behrends, Thilo ; Herrmann, Reimer:
Determination of Distribution Ratios of Aromatic Compounds between Aqueous Solution and Surfactant-Covered Silica by a Chromatographic Method.
In: Scamehorn, John F. ; Harwell, Jeffrey H. (ed.): Surfactant-Based Separations : Science and Technology. - Washington, DC : American Chemical Society , 2009 . - pp. 314-328 . - (ACS Symposium Series ; 740 )
ISBN 9780841236189
DOI: https://doi.org/10.1021/bk-2000-0740.ch019

Abstract in another language

The knowledge of distribution constants between aqueous solution and surfactant covered solid phases is important for the understanding of the process of adsolubilization and for applications based on this process. In this work equilibrium constants of 26 aromatic compounds were determined by a chromatographic method as a function of pH and of the adsorption density of hexadecyltrimethylammonium-bromide (HDTMAB) on silica. The dependency of the retention times on surfactant adsorption changes with increasing HDTMA coverage and is modified by pH. The changes can be explained by the transition of electrostatically driven surfactant adsorption to hydrophobic aggregation. Formation of core regions in the surfactant aggregates due to hydrophobic aggregation favors adsolubilization of non-polar compounds. At the same time equilibrium constants of polar organic compounds decrease because of the reduced interfacial area per surfactant molecule. Facilitated deprotonation of carboxylic and phenolic groups at higher pH results in an increasing adsolubilization efficiency when hydrophobic aggregation is considered and superequivalent adsorption is enabled.

Further data

Item Type: Article in a book
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Chair Hydrology
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 21 Nov 2023 09:27
Last Modified: 21 Nov 2023 09:27
URI: https://eref.uni-bayreuth.de/id/eprint/87825