Adsorption Mechanisms and Electrochemical Properties of Methyl Blue onto Magnetic NixMgyZn(1-x-y)Fe2O4 Nanoparticles Fabricated Via the Ethanol-Assisted Combustion Process

Abstract

Magnetic NixMgyZn(1-x-y)Fe2O4 nanoparticles were fabricated via the ethanol-assisted combustion process. The characterizations of the nanoparticles were illuminated by SEM, EDS, XRD, and VSM. The specific surface area and pore diameter distribution were measured by the Brunauer–Emmett–Teller (BET) measurement. Magnetic Ni0.4Mg0.3Zn0.3Fe2O4 nanoparticles calcined at 400 °C for 2 h with anhydrous ethanol of 20 mL were chosen to remove methyl blue (MB), and their adsorption performances for removal of MB from water environment were evaluated. Adsorption kinetics and adsorption isotherm experiments had been carried out; the adsorption mechanisms were well demonstrated by the pseudo-second-order kinetics model and Temkin isotherm model, respectively, which indicated that the removal of MB by Ni0.4Mg0.3Zn0.3Fe2O4 adsorbent was multimolecular layer chemisorption mechanism. The pH effect of the dye solutions was explored to reveal that the adsorption capacity remained a solidly high level when pH was above 5. After three times of recycling, the relative removal activity of MB onto the nanoparticles remained above 97.6% of its original removal activity. The adsorption process of MB removed by Ni0.4Mg0.3Zn0.3Fe2O4 adsorbent was further illuminated by cyclic voltammetry (CV) and electrochemical impedance spectra (EIS).