Comparative Evaluation of Natural Zeolites for Ammonium Removal from Aqueous Solutions
Natalia Nolasco, Andrea Verrocchi, Jonathan Zaldivar and Yassaman Babaee*
ABSTRACT
Ammonia nitrogen, present in water as ammonium (NH₄⁺) and ammonia (NH₃), is a toxic pollutant that contributes to eutrophication and aquatic life degradation. This study investigates the potential of three natural clinoptilolite zeolites-sourced from Kamloops, BC (Canada), and Preston and Sheaville, ID (USA)-for ammonium removal from aqueous solutions. The zeolites were characterized using X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) to confirm their crystalline structure and functional groups. Batch adsorption experiments were conducted at pH 5.4 and 20 °C with initial ammonium concentrations ranging from 2 ppm to 45 ppm. Results showed that all zeolites maintained structural integrity after adsorption and followed the Langmuir isotherm model, indicating monolayer adsorption on uniform sites. The maximum adsorption capacities (qₘₐₓ) were 3.7, 3.4, and 2.8 mg NH₄⁺/g for Preston, Kamloops, and Sheaville zeolites, respectively. These findings suggest that locally available natural zeolites, particularly those from Preston and Kamloops, are promising, low-cost, and environmentally sustainable adsorbents for the removal of ammonium from low to moderately contaminated waters.
