Perfluorinated pollutants in water: Diffusion coefficient of perfluorosulfonic acids by molecular dynamics simulations

Abstract

Intra-diffusion coefficients of five perfluorinated surfactants (PFAS) (perfluorobutanesulfonic acid (PFBS), perfluorohexanesulfonic acid (PFHxS), perfluorodecanesulfonic acid (PFDS), perfluorododecanesulfonic acid (PFDodS) and the perfluorooctanesulfonate anion (PFOS􀀀 )) in water were determined by molecular dynamics simulation at infinite dilution, as a function of temperature. The results show an excellent agreement with the scarce amount of experimental data available in the literature, lending confidence to the values obtained for PFDS and PFDodS, for which no experimental results could be found. Arrhenius-like equations were adjusted to the temperature dependence of the diffusion coefficients, correlating the diffusion coefficients within the estimated uncertainties. Together with previous studies for perfluorinated alcohols, the data reported is essential for the development of dispersion models of perfluorinated pollutants in water and remediation strategies.