Adsorption Mechanism and Electrochemical Properties of Methyl Blue onto Magnetic CoxCu(1–x)Fe2O4 Nanoparticles Prepared via an Alcohol Solution of Nitrate Combustion and Calcination Process

Magnetic Co x Cu (1–x) Fe 2 O 4 nanoparticles were prepared via an alcohol solution of nitrate combustion and calcination process. Their magnetic properties, microstructure, and element composition were measured by XRD, VSM, SEM, TEM, HRTEM, EDS, BET, and XPS. For larger specific surface area and facile separation from solutions, magnetic Co 0.8 Cu 0.2 Fe 2 O 4 nanoparticles calcined at 400 °C for 2 h with 20 mL absolute ethyl alcohol were employed to adsorb methyl blue (MB). The adsorption mechanism was expounded by the intraparticle diffusion model and the Temkin model, which suggested that the adsorption of MB onto Co 0.8 Cu 0.2 Fe 2 O 4 nanoparticles was the monolayer-multilayer mixed adsorption mechanism. The adsorption of MB onto Co 0.8 Cu 0.2 Fe 2 O 4 nanoparticles kept the high efficiency when the pH of dye solution was equal to or over seven, and the adsorption capacity of Co 0.8 Cu 0.2 Fe 2 O 4 nanoparticles remained 57.1% of the original removal effect after five times circulation. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the adsorption behavior innovatively.