TIME MOMENT ANALYSIS OF SORPTION AND PERMEATION IN LINEAR LAMINATED MEDIA

The time moments of the amount of penetrant (per unit area) in a desorbing membrane or the difference between the instantaneous and asymptotic flow (per unit area) up to a given time through a membrane in a permeation cell can be obtained by numerical integration of experimental data. We show that for membranes composed of a linear laminated medium these time moments can be exactly, recursively calculated without solving the diffusion equation. We then obtain novel, exact functional constraints on the local permeability and distribution coefficients which characterize such a linear laminated medium. We can relate the precursor functions of these time moments to the asymptotic long time behavior of penetrant sorption and permeation. © 1979 American Chemical Society.