Abstract
The capacity of natural zeolites to occlude ammonium nitrate and potassium nitrate by molten salt treatment has been determined, and the salt-occluded zeolites have been characterized. Molten salt treatment resulted in changes of overall and relative intensities of peaks in X-ray diffractograms of zeolites. The presence of occluded salt in zeolites was confirmed by a i.r. absorption band around 1,390 cm-1, exothermic response at 280°C in DTA curve, and type-III nitrogen adsorption/desorption isotherms showing type-H3 hysteresis. The occluded nitrate contents of natural zeolites increased in the following order: erionite > clinoptilolite > chabazite > phillipsite with molten potassium nitrate treatment, and phillipsite > erionite ≥ chabazite > clinoptilolite with molten ammonium nitrate treatment. The present study shows that the capacity of natural zeolites to store nutrients can be increased by salt occlusion and that these occluded zeolites are potential candidates as slow-release fertilizers.
| Original language | English |
|---|---|
| Pages (from-to) | 171-175 |
| Number of pages | 5 |
| Journal | Zeolites |
| Volume | 18 |
| Issue number | 2-3 |
| DOIs | |
| State | Published - 1997 |
Keywords
- Ammonium nitrate
- Characterization
- Natural zeolites
- Potassium nitrate
- Salt occlusion
- Slow-release fertilizer
