AmmoniumN concentration

Figure 9.5. The concentration of ammonium-N in the ion exchanger is shown as a function of the depth at ammonium breakthrough. The ion exchanger is saturated up to the transition zone, where the capacity is not used entirely. The depth of the transition zone is dependent on the flow rate (m/h), but not on the total depth of the column.

Figure 9.5. The concentration of ammonium-N in the ion exchanger is shown as a function of the depth at ammonium breakthrough. The ion exchanger is saturated up to the transition zone, where the capacity is not used entirely. The depth of the transition zone is dependent on the flow rate (m/h), but not on the total depth of the column.

Although clinoptilolite prefers ammonium ions to other cations, it is not absolutely selective and other ions do compete for the available ion exchange capacity. The ion exchange equilibria for the exchange of ammonium versus sodium, potassium, calcium and magnesium are available in the literature. Figure

9.7 gives the selectivity coefficients versus concentration ratios of sodium, potassium, calcium and magnesium respectively. These curves illustrate that clinoptilolite is selective for ammonium relative to all the examined ions except for potassium. It is possible from such curves to predict the ammonium capacity of clinoptilolite in the presence of various concentrations of other cations.

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