Abstract: The aim of this study was to investigate ammonium
exchange capacity of natural and activated clinoptilolite from
Kwazulu-Natal Province, South Africa. X – ray fluorescence (XRF)
analysis showed that the clinoptilolite contained exchangeable ions
of sodium, potassium, calcium and magnesium. This analysis also
confirmed that the zeolite sample had a high silicon composition
compared to aluminium. Batch equilibrium studies were performed
in an orbital shaker and the data fitted the Langmuir isotherm very
well. The ammonium exchange capacity was found to increase with
pH and temperature. Clinoptilolite functionalization with
hydrochloric acid increased its ammonia uptake ability.