Adsorption Mechanism of Reactive Red 2BF onto Magnetic Co0.5Zn0.5Fe2O4 Nanoparticles

Magnetic Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles were prepared by the nitrate-alcohol-solution combustion and calcination technique. The morphology and composition of Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles were characterized by the scanning electron microscopy (SEM), the transmission electron microscopy (TEM), the X-ray diffraction (XRD), the energy-dispersive spectroscopy (EDS), the vibrating sample magnetometer (VSM), the Fourier transform infrared spectrometer (FTIR), and the Brunauer-Emmett-Teller measurement (BET). The concentration of the ferric nitrate and the calcination temperature were the two key factors to the property of Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles. To achieve greater adsorption capacity and durability of materials, magnetic Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles calcined at 400 °C with ferric nitrate concentration of 0.84 M were employed to remove reactive red 2BF (RR-2BF). The pseudo-second-order kinetic model could be applied to describe the adsorption process of RR-2BF onto Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles in the initial RR-2BF concentrations of 100–400 mg L⁻¹, and the adsorption process could be fitted well by Langmuir model. The above adsorption experiments results suggested that the adsorption of RR-2BF onto Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles was the monolayer adsorption mechanism. The effect of the dye solution pH on the adsorption process had been explored. At the same time, the removal efficiency for RR-2BF onto Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles could maintain more than 72% after 10 cycles. Graphical Abstract Magnetic Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles were prepared by the novel nitrate-alcohol-solution combustion and calcination technique, and they were employed to remove reactive red 2BF (RR-2BF) from aqueous solution. The adsorption mechanism of RR-2BF onto Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles was investigated, the pseudo-second-order kinetic model and the Langmuir isotherm model fitted well with the experimental data, and Co₀.₅Zn₀.₅Fe₂O₄ nanoparticles revealed favorable recycling performance.