Dynamics of Micropollutant Adsorption to Polystyrene Surfaces Probed by Angle-Resolved Second Harmonic Scattering

William T. S. Cole, Haoyun Wei, Son C. Nguyen, Charles B. Harris, Daniel J. Miller, Richard J. Saykally

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Angle-resolved second harmonic scattering is used to probe the adsorption dynamics of aqueous cationic and anionic dye molecules onto polystyrene surfaces. The adsorptions of malachite green to negatively charged polystyrene and naphthol yellow S to positively charged polystyrene are both highly favorable, with Î"GAds values of -10.9 ± 0.2 and -10.27 ± 0.09 kcal/mol, respectively. A competitive displacement methodology was employed to obtain values for the adsorption free energies of various smaller neutral organic molecules, including the important micropollutant ascorbic acid, caffeine, and pentoxifylline. For charged adsorbers, electrostatic interactions appear to significantly contribute to adsorption behavior. However, electrostatic repulsion does not necessarily deter the adsorption of molecules with large uncharged moieties (e.g., surfactants). In these cases, the mechanism of adsorption is dominated by van der Waals interactions, with the surface charge playing a relatively minor role.
Original languageEnglish (US)
Pages (from-to)14362-14369
Number of pages8
JournalThe Journal of Physical Chemistry C
Volume123
Issue number23
DOIs
StatePublished - May 22 2019
Externally publishedYes

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials

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