A theoretical treatment of the effects of Ionic and non-ionic competitive adsorption during solute transport in soils

Abstract

The method of characteristics is used to analyse multi-species solute movement through a non-linearly reactive soil taking dispersion into account. Both ionic and non-ionic solutes are considered, and it is shown that the shape of a solute front depends on the shape of the adsorption isotherms. At large times, overall solute movement is effected by a series of solute fronts moving independently. The composition of each front, and hence individual solute concentrations within the front, are determined by the degree of competition reflected in the adsorption isotherms. Varying water contents are considered explicitly, although the detailed analysis is restricted to uniform water contents for simplicity.