Fractional derivative model for diffusion-controlled adsorption at liquid/liquid interface.

The Ward-Tordai integral equation governs the diffusion-controlled surfactant adsorption at air/liquid interfaces. In this paper the Ward-Tordai equation is generalized in two directions. First, the adsorption is assumed to take place at a liquid/liquid interface, where the surfactant is soluble in both liquid phases. Second, the diffusion in the bulk phases is anomalous and is governed by time-fractional diffusion equations. For the computation of the change of adsorption with time two numerical techniques are proposed and compared. Numerical results are presented. [ABSTRACT FROM AUTHOR]