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Water Res. 2010 Jun;44(12):3651-8. doi: 10.1016/j.watres.2010.04.014. Epub 2010 Apr 24.

Mechanisms controlling adsorption of natural organic matter on surfactant-modified iron oxide-coated sand.

Author information

1
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.

Abstract

Mechanisms contributing to the adsorption of natural organic matter (NOM) on surfactant-modified iron oxide-coated sand (IOCS) were explored by microscopic surface characterization techniques and adsorption tests. Electrostatic interactions that were thought to be from the positively charged, surface-coated surfactant, hexadecyltrimethyl ammonium (HDTMA), seemed to be unimportant, likely because the outward-pointing tail groups of the surface-coated HDTMA monolayers hindered the interactions. Improved hydrophobic interactions followed by ligand exchange are believed to be the dominant mechanisms. Atomic force microscopy (AFM) force analysis with chemically modified tips was used to explore the adsorption mechanisms between NOM and IOCS, where an iron oxide-coated mica surface was utilized as a substitute for the IOCS surface. It demonstrates the changes of pull-on forces and the increases in hydrophobic interactions from the modification of IOCS with HDTMA.

PMID:
20457463
DOI:
10.1016/j.watres.2010.04.014
[Indexed for MEDLINE]

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