Ahrens, Lutz
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
Abstract
Counter-ions have large effects on the self-assembly and dispersion of per-and polyfluoroalkyl substances (PFAS) in aqueous solution. PFAS have been recognized as emerging contaminants of concern due to their ubiquitous distribution in the environment and persistent and potential toxic characteristics. The aim of this study was to investigate how different counter-ions affect perfluorooctanoate micelle assembly and interactions. Small-angle X-ray scattering was used to determine the influence of ions (Li+, Na+, NH4+, Mg2+) on the micelles and their interactions. The micelles formed by perfluorooctanoate in the presence of monovalent counter-ions (Li+, Na+, NH4+) were characterized as highly charged cylinders that became more elongated as the surfactant concentration increased. In the presence of added sodium chloride, the sodium perfluorooctanoate micelles were more elongated and, with 0.2 M NaCl, electrostatic interactions were screened almost completely. The micelles formed by perfluorooctanoate in the presence of the divalent magnesium ions were cylinders and the length increased markedly at higher concentrations and at lower temperatures. The interactions were screened by the divalent ions without further added electrolyte. As the formation of micelles influences the transport and dispersion of PFAS in the environment, the results will be valuable in understanding processes related to pollution and improving remediation methods.
Keywords
Micelles; PFAS; Perfluorooctanoate; Counter-ions; Small-angle X-ray scattering; Interactions
Published in
Colloids and Surfaces A: Physicochemical and Engineering Aspects
2025, volume: 726, number: Part 3, article number: 137912
Publisher: ELSEVIER
SLU Authors
UKÄ Subject classification
Physical Chemistry
Publication identifier
- DOI: https://doi.org/10.1016/j.colsurfa.2025.137912
Permanent link to this page (URI)
https://res.slu.se/id/publ/144019