Potassium-calcium exchange equilibria

The following example of advective transport in the presence of a cation exchanger is derived from a sample calculation for the program phreeqm (Appelo and Postma, 1993, example 10.13, pp. 431 134). The chemical composition of the effluent from a column containing a cation exchanger is simulated. Initially, the column contains a sodium-potassium-nitrate solution in equilibrium with the cation exchanger. The column is then flushed with three pore volumes of calcium chloride solution. Calcium, potassium, and sodium react to equilibrate with the exchanger at all times. 

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