No-flow equilibration and adsorption dynamics during ionic transport in soils

Abstract

Methods for predicting the movement of adsorbing chemicals such as fertilisers, pesticides, herbicides and heavy metals in soils have received increasing attention because of their importance in relation to the efficiency of fertiliser usage and in the control of agricultural and industrial pollutants¹. Because of the difficulty in coping with the complex non-linear partial differential equations necessary to describe the dispersive–convective–adsorptive flow process, analytical solutions have been largely limited to the assumptions of instantaneous equilibrium and simple linear adsorption isotherms^2–5. We demonstrate here the need to incorporate adsorption dynamics to describe adequately practical situations, particularly those involving intermittent flow.