Assessment of Sustainable Geopolymer‐Based Adsorption for Ammonia Removal from Wastewater

ABSTRACT Fly ash, a by‐product of coal combustion in thermal power plants, is generated in large quantities worldwide. With increasing environmental awareness, its reuse has gained significant attention across various sectors. Adsorption is a process in which pollutants in water, such as ammonia, phosphate, or heavy metals, adhere to the surface of a solid material known as an adsorbent. Common adsorbents include activated carbon, fly ash, and geopolymers. This study aims to evaluate the efficiency of a fly ash‐based geopolymer in reducing ammonia concentrations from wastewater. The geopolymer is synthesized using fly ash, active silica, and a sodium hydroxide solution. After curing the prepared geopolymer at room temperature for 28 days, compression tests were conducted to assess its strength. Characterization was carried out using X‐ray Diffraction (XRD) and X‐ray Fluorescence (XRF) techniques. Field Emission Scanning Electron Microscopy (FESEM) was used to examine the surface morphology of the geopolymer before and after adsorption. The characterization results confirmed the suitability of the geopolymer as an effective adsorbent, and the FESEM analysis showed that ammonia molecules had successfully adsorbed onto its surface.