Activating Illite kaolinite clay with CTAB for adsorbing Methylene blue: Isotherms, Kinetics, and thermodynamics studies

Abstract

In this study, a stable multilayered adduct of maghemite surfactant and clay was created by sandwich-like electrostatic self-assembly of cationic polyelectrolytes of cetyltrimethylammonium bromide (CTAB) with illite kaolinite (IKaol) clay. The adsorptive property of  IKaol/CTAB towards MB from . Aquatic system uptake was investigated. Its characteristics were analysed using X-ray powder diffraction, Fourier transform-infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, and the zero point of charge. To attain higher performance of the IKaol/CTAB for MB adsorption, the primary key factors that influence the MB dye, such as (A: loading CTAB into the composite matrix of IKaol), adsorbent dose (B: 0.02–0.06 g), pH (C: 4–10), temperature (D: 30–60 °C), and time (E: 5–60 min) , were optimised using the Box–Behnken design method. The obtained results show that the highest MB removal efficiency of 86.24 % was observed at the following significant interactions: AB, BC, and AC and at optimum adsorption operation parameters (A: 0%, B: 0.06 g, C: 7, D: 45◦C, and E: 17.5 min). At these optimum conditions, the best adsorption capacity of MB dye (114.94 mg/g) was recorded at 45°C. The most effective isotherms and kinetic models were the Freundlich and pseudo-second-order kinetic models. The MB dye adsorption mechanism by IKaol can be assigned to several interactions, such as electrostatic attractions, n-π interaction, and hydrogen bonding interactions. The results of this study demonstrate the viability of IKaol as a promising precursor for the creation of an efficient adsorbent that can be used to remove cationic dye from an aqueous environment.