Preparation of Magnetic Ni _x Co_(1−x)Fe₂O₄ Nanoparticles by the Rapid Combustion Approach and Their Adsorption of Reactive Red 2BF

A rapid combustion approach for the preparation of magnetic Ni _x Co_(1−x)Fe₂O₄ nanoparticles was introduced. The experimental results showed that the content of Ni in Ni _x Co_(1−x)Fe₂O₄ nanoparticles, the volume of absolute alcohol and the calcination temperature were three key factors to grain size, crystallinity and properties of magnetic Ni _x Co_(1−x)Fe₂O₄ nanoparticles, and the influence rules of which were revealed. The magnetic Ni_0.4Co_0.6Fe₂O₄ nanoparticles that calcined at 400 °C for 2 h with the heating rate of 3 °C/min and absolute alcohol of 40 mL were employed to remove Reactive Red 2BF (RR-2BF) from aqueous solution, and the adsorption kinetic and the adsorption isotherm of RR-2BF onto them were investigated at room temperature. The kinetic data were in good agreement with the pseudo-second-order kinetic model with the initial RR-2BF concentrations of 100–500 mg/L; the adsorption equilibrium data were analyzed with Langmuir, Freundlich and Temkin models, and the adsorption isotherm was most effectively described by the Temkin model based on the correlation coefficient (0.9985); the magnetic Ni_0.4Co_0.6Fe₂O₄ nanoparticles showed better adsorption of RR-2BF under acidic condition.