SIMULTANEOUS TRANSPORT OF Cl, Na, AND Ca IONS IN UNDISTURBED SOIL COLUMNS

摘要

The convective-dispersive mass transport (GOT) of adsorbed and slightly adsorbed solutes is being studied quite intensely. For slightly adsorbed solutes the main cause of solute retention in a soil sample is physical heterogeneity, which makes itselfevident in variability of intraporous rates of transport, and formation of parts of pore space called, as a matter of convention, flow and stagnation zones [1-3]. The reaction centers of a soil adsorbing complex with different degrees of affinity for a adsorbed solute of organic or inorganic nature govern chemical heterogeneity of soils for an adsorbed solutes [4, 5]. The best results for such solutes are obtained on models founded on the principles of the existence of sorption sites with different exchange rates and capacities [6]. It can be inferred from numerous publications that for slightly adsorbed compounds the most important transport-regulating property is physical heterogeneity of soil. Transport of adsorbed substances, i.e., ions, is largely governed by mechanisms of chemical interaction with the organo-mineral complex of soil.