Magnetized bentonite by Fe3O4 nanoparticles treated as adsorbent for methylene blue removal from aqueous solution: Synthesis, characterization, mechanism, kinetics and regeneration

• The adsorption trend was discussed with four different kinetics models.
• Factors affecting the adsorption of MB were investigated in details.
• Possible mechanism of the adsorption system was carefully discussed.
• Adsorbent showed a high adsorption capacity and an efficient adsorption toward MB.
• Regeneration of magnetic adsorbent was obtained via gamma-irradiation.

In this work, we carried out the adsorption of methylene blue (MB) onto a kind of adsorbent, which was magnetized bentonite by Fe3O4 nanoparticles (MBF) using a quick, efficient and low-cost one-pot method. The characterization of the adsorbent conducted via SEM, EDS, VSM, XRD, BET and FT-IR spectroscopy. The adsorption trend follows the pseudo-second order kinetics model and the equilibrium could be established within 20 min. Factors affecting the adsorption of MB such as pH, adsorbent dosage, contact time, and initial concentration of MB were investigated. The role of ─OH functional group in this adsorption process was discussed. MBF showed a high adsorption capacity and an efficient adsorption toward MB in aqueous medium and implies the great potential application in the treatment of colored wastewaters. Regeneration of the saturated adsorbent was easily carried out with gamma-irradiation of a certain dose.