COMPETITIVE ADSORPTION DURING SOLUTE TRANSPORT IN SOILS

Abstract

One-dimensional, convective-dispersive-adsorptive flow models, in Cartesian and polar coordinates, representing flow of chemicals in soils (e.g., leaching) and toward plant roots, are generalized to competitive multispecies systems. Langmuir-type competitive adsorption models suitable for equilibrium and dynamic interactions are presented, and a few special simplified cases are discussed. Freundlich-type equilibrium adsorption models are modified to multispecies situations. An empirical approach, capable of handling most general equilibrium adsorption isotherms, suitable for multispecies systems, is also described. The empirical approach is comparable to equilibrium Langmuir and Freundlich-type competition in binary systems. Isotopic exchange, which is a form of competition between isotopes of the species for adsorption or exchange sites, may be described through a simple McKay-type equation.