Evaluation of Fe3O4@MnO2 core-shell magnetic nanoparticles as an adsorbent for decolorization of methylene blue dye in contaminated water: Synthesis and characterization, kinetic, equilibrium, and thermodynamic studies

In this study, Fe3O4@MnO2 core-shell nanoparticles were synthesis by a simple one-pot method. These nanoparticles were applied for removal of methylene blue (MB) ions from aqueous solution by a batch technique and characterized by TEM, XRD, EDS, FTI), FE-SE, VSM and BET surface area measurement. The influence of different adsorption parameters, such as contact time, adsorbent dosage, initial concentration of MB ions, pH value of solution and temperature have been investigated. Three isotherm equations, Langmuir, Freundlich, and Tempkin, have been tested in order to describe the equilibrium characteristics of adsorption. The equilibrium data for adsorption of MB were fitted well by Freundlich isotherm and the maximum adsorption capacity of Langmuir was 434.78 mg/g at 298 K approximately. The experimental results were fitted better with pseudo-second-order model compared to the other two models. In addition, thermodynamic calculations revealed that the adsorption process was spontaneous, exothermic and feasible. The result of experimental shows that Fe3O4@MnO2 nanoparticles is -suitable adsorbent for removal of MB from aqueous solutions. (C) 2017 Elsevier B.V. All rights reserved.