Adsorption characteristics of methyl blue onto magnetic Ni0.5Zn0.5Fe2O4 nanoparticles prepared by the rapid combustion process

Magnetic Ni0.5Zn0.5Fe2O4 nanoparticles were prepared by the rapid combustion process and their microstructure and magnetic properties were investigated by XRD, SEM, EDX, and VSM. The as-prepared magnetic Ni0.5Zn0.5Fe2O4 nanoparticles were characterized with about 16 nm grains and specific magnetization of 46.0 Am-2/kg. The adsorption kinetics and adsorption isotherms of methyl blue onto the magnetic Ni0.5Zn0.5Fe2O4 nanoparticles at room temperature were investigated. The kinetics data related to the adsorption of methyl blue from aqueous solutions are in good agreement with the pseudo-second-order kinetic model in a range of initial concentration of 50-300 mg/L. By comparison of the Langmuir, Freundlich, Temkin and Redlich-Peterson models for adsorption isotherms of methyl blue, the Temkin model (correlation coefficient R-2 = 0.9912) and Redlich-Peterson model (correlation coefficient R-2 = 0.9963) can be used to evaluate the methyl blue adsorption isotherm at room temperature. The adsorption capacity of methyl blue onto magnetic Ni0.5Zn0.5Fe2O4 nanoparticles reaches the maximum value at pH 3.