An innovative alcohol-solution combustion-calcination process for the fabrication of NiFe2O4 nanorods and their adsorption characteristics of methyl blue in aqueous solution

Magnetic nickel ferrite (NiFe2O4) nanorods were prepared via an innovative alcohol-solution combustion-calcination technique and evaluated for removing methyl blue (MB), which may greatly benefit for dye-polluted water treatment. The magnetic nanorods were characterized by TEM, EDS, XRD, VSM, SAED, FTIR, XPS and BET, the results showed that the NiFe2O4 sample has high magnetic saturation (Ms) and soft superparamagnetic behavior, and these properties accounted for their facile separation from the aqueous solution when an external magnetic field was applied. To understand the adsorption mechanism, adsorption experiments were performed using adsorption kinetics and adsorption isotherms. The Temkin model and the pseudo-second-order kinetic model best described the adsorption characteristics of MB onto NiFe2O4 nanorods. The effect of pH on the adsorption process was investigated, when pH was 3–7, the maximum adsorption capacity was reached, which was about 62 mg·g−1. The recycling efficiency was also estimated, after 10 runs of regeneration, it remained 70.1% initial adsorption capacity, indicating the adsorbent could be efficiently reused for the adsorption of MB.