Displacement measurements connection coefficients

In experiments at trace level or very low loading of one ion, the isotope dilution procedure is not required. All that is necessary is that the exchangeable ions on the solid be those of the salt present in macro concentration. The computation of results, which followed that conventionally used in the determination of distribution coefficients, ignores possible effects of colon exclusion from water in the clay pack it is implicitly assumed that the water in the pack has the same coion concentration as the supernatant solution. It is possible that coion exclusion has an effect which may be significant on distribution coefficients (particularly when they are low) and on capacities computed from the results. We shall discuss this interference later in connection with the capacities measured by displacement of both cations and anions from the clay pack and associated water. Coion exclusion has been further discussed in references 1 and 7 (see also 8, 9, and 10). 

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