title: Adsorption of perfluorocarboxylic acids at the silica surface.
abstract: Water molecules may force the hydrophobic perfluoroalkyl chain of perfluorocarboxylic acids (PFCAs) to aggregate at hydrophobic siloxane patches ([triple bond, length as m-dash]Si-O-Si[triple bond, length as m-dash]) of the silica surface despite electrostatic repulsion between surface silanol ([triple bond, length as m-dash]SiO-) and the carboxylate (-COO-) headgroup of PFCA. Acidic pH and background cations promote the adsorption further by reducing the anion-anion Coulomb repulsion.
authors.affiliation: UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany. gerrit.schuurmann@ufz.de and Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Straße 29, 09596 Freiberg, Germany.
authors.forename: Umer
authors.initials: U
authors.lastname: Shafique
authors.affiliation: Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Straße 29, 09596 Freiberg, Germany.
authors.forename: Vivien
authors.initials: V
authors.lastname: Dorn
authors.affiliation: UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany. gerrit.schuurmann@ufz.de.
authors.forename: Albrecht
authors.initials: A
authors.lastname: Paschke
authors.affiliation: UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany. gerrit.schuurmann@ufz.de and Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Straße 29, 09596 Freiberg, Germany.
authors.forename: Gerrit
authors.identifier: http://orcid.org/0000-0002-3789-1703
authors.initials: G
authors.lastname: Schüürmann
mesh_terms: D000327:Adsorption; D005466:Fluorocarbons / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D005466:Fluorocarbons; D012822:Silicon Dioxide