Preparation and characterization of a novel chitosan/Al2O3/magnetite nanoparticles composite adsorbent for kinetic, thermodynamic and isotherm studies of Methyl Orange adsorption

Also, the adsorption activity of synthesized adsorbent including kinetics, thermodynamics, isotherm and desorption were comprehensibly studied. The adsorption isotherm was well described by the Langmuir model and showed high MO adsorption capacity (1.27 mmol g−1, i.e., 417 mg g−1 at 25 °C). MO adsorption kinetics followed a pseudo-second-order kinetic model, indicating that adsorption was the rate-limiting step. At 10 mg L−1, only 14 min was required to reach 93% adsorption and about 50% of the MO was adsorbed in 2 min. The fitting of experimental data with Weber and Morris model indicates that the adsorption kinetic was controlled simultaneously by film diffusion and intra-particle diffusion. Furthermore, the desorption studies of MO using 0.1 M HCl showed the reusability of the adsorbent.