IONIC TRANSPORT IN SOIL WITH ION-EXCHANGE REACTION

A mathematical model describing the transport of two ions in an exchange material such as soil, was described. Concentration profiles of displacing ion, A, and an ion being displaced, B, were obtained using the numerical solution of the two simultaneous transport equations A and B. The variations in the concentration distributions were investigated by varying the selectivity coefficient of ion exchange reactions, valences of A and B, the magnitude of incoming concentration, and cation exchange capacity under constant flow rate of soil solution and dispersion coefficient. The results of the analyses indicated that the concentration distributions of displacing and displaced ions within a soil column can be related to the selectivity coefficient of the ion exchange reaction, exchange capacity, and concentration of the displacing ion.