SO 2 diffusion through acetonitrile-saturated perfluorosulfonic acid membranes

The diffusion coefficient of SO 2 and acetonitrile in Nafion perfluorinated ion exchange membranes have been determined from chromatographic measurements of SO 2 concentration and the isotopic ratios in acetonitrile solutions. The diffusion coefficients vary with residual water content and attain values about one fifth those reported for water-saturated membranes falling in the range 1–2 × 10 −7 cm 2 s −1 . Values obtained for Teflon reinforced material indicates diffusion takes place over an effective surface more than twice the optically open area.