Conversion of Glass Waste into Zeolite A Adsorbent for Efficient Ammonium Ion Adsorption from Aqueous Solution: Kinetic and Isotherm Studies

Abstract

In this study, a zeolitic adsorbent (AGW-ZA) was successfully developed from glass waste (GW)-derived aluminosilicates. The GW, serving as the starting material, underwent alkaline activation and hydrothermal treatment to yield the AGW-ZA adsorbent, which exhibited a surface area of 216.48 m2/g. The AGW-ZA demonstrated significantly higher ammonium (NH4+) ion adsorption (142.5 mg/g at 1000 mg/L) than pristine GW (80.0 mg/g). Optimal adsorption experimental parameters were identified (0.1 g dosage, pH = 7, and 10 h contact time) to determine the maximum NH4+ ions’ adsorption potential by adsorbents. Kinetic and isotherm models were applied to experimental data to describe the adsorption mechanisms. The pseudo-second-order model provided the best fit for both AGW-ZA and pristine GW, indicating that the adsorption process is followed by chemical interaction via ion exchange. Regarding isotherms, the Freundlich model was most suitable for AGW-ZA, signifying that NH4+ ions adsorbed on heterogeneous adsorbent surfaces by forming multilayers, while the Temkin model fit the pristine GW data, indicating the chemisorption nature with medium adsorbate–adsorbent interactions above the heterogeneous surface. This study explores the potential of transforming discarded GW into a high-performance zeolitic adsorbent for the mitigation of environmental pollution by removing NH4+ ions from wastewater while simultaneously addressing waste management challenges.