Fe3O4 Nanoparticles Loaded Bentonite/Sawdust Interface for the Removal of Methylene Blue: Insights into Adsorption Performance and Mechanism via Experiments and Theoretical Calculations

Herein, magnetite nanoparticles (MNPs) synthesized from altered basalt were used to develop a composite with H2O2–activated bentonite (BE) and fibrous sawdust (SD). The as-prepared BE/SD–MNPs characterized by FTIR, FESEM, TEM, TGA, DSC, Zeta potential techniques utilized as an effective multifunctional for removing methylene blue (MB). adsorption isotherms of MB at 25–55 °C analyzed via kinetics, classical, advanced statistical physics models. Theoretically, the pseudo-second-order kinetics Freundlich model fit experimental data well without microscopically clarifying mechanism. Studying multilayer model’s steric energetic parameters was reliable approach understanding uptake mechanism molecular scale. Sterically, removed molecules offered combination horizontal vertical geometry (i.e., mixed orientation). capacity saturation (Qsat) increased 829 849 mg/g temperature, suggesting endothermic interactions. Energetically, controlled physical interactions energy < 20 kJ/mol). retained more than 85% after five adsorption-desorption rounds. Overall, this study aimed understand using magnetic clays/lignocellulosic interface such promising strategy in wastewater remediation.