Adsorption Performances and Electrochemical Characteristic of Methyl Blue onto Magnetic Mg_xCu_(1-x)Fe₂O₄ Nanoparticles Prepared via the Rapid Combustion Process

Magnetic Mg_xCu_(1-x)Fe₂O₄ nanoparticles were prepared by the rapid combustion method, and characterized by TEM, VSM and XRD techniques. For larger specific surface area and larger adsorption capacity, magnetic Mg_0.5Cu_0.5Fe₂O₄ nanoparticles calcined at 400 ºC for 2 h with an average particle size of 32.3 nm were employed to remove methyl blue (MB), and the adsorption mechanism of MB onto Mg_0.5Cu_0.5Fe₂O₄ nanoparticles was investigated. The correlation coefficient (R²) values of the second-order kinetic model and Freundlich model for fitting the adsorption data of MB onto Mg_0.5Cu_0.5Fe₂O₄ nanoparticles reached more than 0.99, which suggested that the adsorption of MB onto Mg_0.5Cu_0.5Fe₂O₄ nanoparticles belonged to the chemical multilayer adsorption mechanism. When pH ≥ 3, the adsorption capacity reached maximum of 159 mg/g. However, when pH < 3, the adsorption capacity kept a minor value, which indicated that the adsorption capacity could be controlled by changing pH value. After 12 cycles, the adsorption capacities of the Mg_0.5Cu_0.5Fe₂O₄ nanoparticles could still reach 83% of the first adsorption capacity, revealing that the magnetic Mg_0.5Cu_0.5Fe₂O₄ nanoparticles had large adsorption capacity and reuse ability, and the equilibrium time of adsorption was about 80 min, indicating that Mg_0.5Cu_0.5Fe₂O₄ nanoparticles had practical application potential.

Magnetic Mg_0.5Cu_0.5Fe₂O₄ nanoparticles were prepared via a rapid combustion process with anhydrous ethanol as solvent and fuel and characterized, and the adsorption mechanism of MB onto magnetic Mg_0.5Cu_0.5Fe₂O₄ nanoparticles were revealed using MB as template.