Effect of Ion Adsorption on Solute Transport in Saturated Porous Media

Use of mathematical models as efficient tools in solute transport studies and management in porous media is usual. The present model by making use of the governing equation for two - dimensional solute transport in a porous medium expresses the ion adsorption effect on solute transport in a saturated semi infinite porous medium.This model has been solved analyticaly under the first type (Dirichlet condition) and the third type (Cauchy condition) boundary conditions. In solute transport by diffusion, the third type boundary condition shows the solute concentration at the boundary or on the soil surface more than that of the first boundary condition. In advection – dispersion solute transport, the solute concentration distribution curves resulting from the first and third boundary conditions because of advection predomination are approximately identical. The effect of ion adsorption on the medium,s solid matrix is evaluated by retardation factor in the model. The retardation factor greater than one causes retardation in solute transport, distribution and dispersion in the medium. The effect of ion adsorption on solute concentration distribution is independent of the selected boundary condition and depends on the modes of solute transport and dispersion in the medium, so as the rate of this effect in advection – dispersion solute transport is more than in diffusion transport.