Adsorption isotherm and kinetic modeling of malachite green (MG) dye on cost-effective mesoporous material Al-MCM-41 synthesized from local clay

Abstract

This study aimed to produce the cost-effective mesoporous material “aluminum-modified MCM-41” using local Saidite clay for efficient removal of Malachite Green (MG) dye from an aqueous solution. Characterization of the products involved the use of X-ray diffraction (XRD), N₂ adsorption and desorption, and scanning electron microscopy (SEM). The X-ray diffraction analysis confirmed the successful synthesis of pure Al-MCM-41 without any impurities. The surface area of the sample was determined to be approximately 660 m²/g. Various parameters, including contact time, adsorbent dosage, initial pH of the solution, dye solution concentration, and temperature, were taken into account. At a temperature of 298 K, the maximum adsorption capacity for MG was found to be 55 mg/g. Both adsorption isotherm and kinetic models were examined, revealing that the Langmuir model best described the adsorption phenomenon. Furthermore, the adsorption kinetics followed the pseudo-second-order kinetic model, demonstrating a high correlation coefficient (R² = 0.99). Additionally, the study discussed the mechanical interaction between the removal of MG and Al-MCM-41.