Ammonia is a toxic pollutant found in wastewater, leading to the degradation of water resources and aquatic ecosystems in particular. Clinoptilolite is a natural adsorbent that enables the removal of ammonium from water. This study aimed to improve the adsorption capacity of clinoptilolite for ammoniacal nitrogen, evaluate ammonium adsorption and desorption, and explore its potential for reuse in agriculture.
Calcination at 200 °C increased the adsorption capacity of clinoptilolite from 2.32 to 4.66 mg N-NH4 + /g. Experimental trials demonstrated the high efficiency of activated clinoptilolite for ammonium adsorption. The obtained yields varied between 94 % and 96 % across a pH range of 3,0 to 10,0. For initial ammonium concentrations of 50 to 300 mg/L N-NH4 + , the adsorption efficiency ranged from 96 % to 97,2 %. Regarding contact time, nearly 80 % of the ammonium was adsorbed within the first 30 minutes. Finally, the application of an optimal dose (2 g) of clinoptilolite achieved an adsorption efficiency of up to 95 %. Furthermore, the study of ammonium release by clinoptilolite in media simulating natural environments showed that the material effectively releases ammonium in a progressive manner. In the receiving medium, initially free of ammoniacal nitrogen (0 mg/L N-NH4 + ), a concentration of 4,9 mg/L N-NH4 + was observed after 10 days, reaching a maximum of 92.4 mg/L N-NH4 + after 55 days. However, the presence of nitrifying bacteria accelerates the release process, as these microorganisms contribute to the transformation of ammonium into other forms of nitrogen notably nitrites and then nitrates which are assimilable by plants. After 55 days, the clinoptilolite had released approximately 23 % of its initial nitrogen content, highlighting the possibility of natural and progressive long term material regeneration. Finally, ecotoxicological analysis revealed that clinoptilolite whether natural, calcined, and/or nitrogen enriched has no toxic effect on the germination of lettuce seeds. However, an excessive amount of clinoptilolite in culture media can have consequences for the morphology of young plants.
| Date | 12 Jan 2026 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Robert Hausler (Supervisor) |
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Doubla Aicha Abatcha, N. (Author),
Hausler (Supervisor),
12 Jan 2026Student thesis: Master's thesis › Master in Engineering: Environmental Engineering