Fly Ash-Based Porous Geopolymer – A Prospective Ceramic Adsorbent for Wastewater Treatment

Abstract

Industrial wastewater treatment has been a serious global issue in recent decades, and waste management necessitates the invention of new, cost-effective, sustainable technologies. There is a massive demand for potential wastewater purification methods using eco-friendly waste materials. Vast quantities of industrial waste can be utilized using the circular economy principles in wastewater treatment methods. Adsorption is the most affordable, reliable, and quickly operational wastewater treatment method [1]. There is a growing demand for sustainable and porous geopolymer adsorbents using a waste-to-money solution approach in the 21st century. In particular, fly ash has stood out as a suitable, affordable, and efficient adsorbent due to its high porosity, surface area, and mineral composition [2]. This study used fly ash with clay and slag to prepare a geopolymer-based adsorbent. The work includes geopolymer precursor preparation by mixing fly ash, clay, and blast furnace slag, maintaining three different ratios (50:20:30, 55:20:25, and 60:20: 20) and alkali activation of the prepared precursors using an activator solution of sodium silicate with sodium hydroxide maintaining the ratio SiO2/Na2O 1.3. The activation was done by stirring the precursor mix with the activator solution for hours; the slurry was dried and cured at room temperature until characterization. Comprehensive characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Infrared spectroscopy (IR), and Nitrogen adsorption-desorption isotherms reveal the detailed microstructure, phase, functional group, and surface properties of the product. Below attached XRD pattern of synthesized powder shows an amorphous hump in the (20-34 degree) 2theta range indication geopolymerization process. The batch adsorption study to estimate the efficiency of the prepared adsorbent for wastewater treatment is continuing. Therefore, this work of preparation of geopolymer-based powder adsorbent using waste material and its efficient use in dye removal from wastewater may offer an inexpensive solution to environmental issues.