Sorption of perfluorinated surfactants on sediments.
The sorption of anionic perfluorochemical (PFC) surfactants of varying chain lengths to sediments was investigated using natural sediments of varying iron oxide and organic carbon content. Three classes of PFC surfactants were evaluated for sorptive potential: perfluorocarboxylates, perfluorosulfonates, and perfluorooctyl sulfonamide acetic acids. PFC surfactant sorption was influenced by both sediment-specific and solution-specific parameters. Sediment organic carbon, rather than sediment iron oxide content, was the dominant sediment-parameter affecting sorption, indicating the importance of hydrophobic interactions. However, sorption also increased with increasing solution [Ca2+] and decreasing pH, suggesting that electrostatic interactions play a role. Perfluorocarbon chain length was the dominant structural feature influencing sorption, with each CF2 moiety contributing 0.50-0.60 log units to the measured distribution coefficients. The sulfonate moiety contributed an additional 0.23 log units to the measured distribution coefficient, when compared to carboxylate analogs. In addition, the perfluorooctyl sulfonamide acetic acids demonstrated substantially stronger sorption than perfluorooctane sulfonate (PFOS). These data should prove useful for modeling the environmental fate of this class of contaminants.
Higgins
Christopher P
CP
Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305-4020, USA.
Luthy
Richard G
RG
D000327:Adsorption; D002118:Calcium / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D002853:Chromatography, Liquid; D005290:Ferric Compounds / Q000737:chemistry; D019015:Geologic Sediments / Q000032:analysis*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D013501:Surface-Active Agents / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
D005290:Ferric Compounds; D006845:Hydrocarbons, Fluorinated; D013501:Surface-Active Agents; C000499:ferric oxide; D002244:Carbon; D002118:Calcium