Preparation of geopolymeric adsorbent from the acid leached kaolin and using in methylene blue removal from wastewater

This study explored the feasibility of utilizing acid-leached kaolin residue resulted from the manufacturing process of kaolin-based aluminum sulfate for preparation of geopolymers as adsorbents for removal of methylene blue (MB) from aqueous solutions. A comprehensive characterization was performed using X-ray diffraction (XRD, X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) coupled with energy dispersive X-ray analysis (EDX). The influence of diverse experimental parameters, such as geopolymer dosage, pH level, initial dye concentration, contact duration, and temperature were examined. The Optimal adsorption conditions were determined, including adsorbent dosage equal to 3 g/L, initial dye concentration 30 mg/l, contact time of 3 hours, and pH equal to 10. The adsorption capacity equal to 25.36 mg/g. The kinetic process’s findings were in accordance with the pseudo-second-order model. Langmuir and Freundlich isotherm models were applied to analyze the equilibrium data. The Freundlich model revealing a strong correlation coefficient. Keywords: Acid leached kaolin, adsorption, geopolymer, methylene blue removal, wastewater treatment.