Structural analysis and catalytic activity of Fe3O4 nanoparticles prepared by a facile co-precipitation method in a rotating packed bed

Fe3O4 nanoparticles were prepared via a facile co-precipitation method in a rotating packed bed (RPB) in a continuous mode. Exactly how the rotating speed, flow rates of the reactants and precipitant, and concentrations of the reactants and precipitant affect the size of Fe3O4 nanoparticles was also investigated. Experimental results indicate that a higher rotating speed and larger flow rates of the reactants and precipitant were associated with a smaller size of Fe3O4 nanoparticles. However, concentrations of the reactants and precipitant only slightly affected the size of Fe3O4 nanoparticles. Additionally, the structural characterization of as-prepared Fe3O4 nanoparticles with an average size of 5.1 nm was studied using SEM, TEM, FTIR, XPS, and SQUID. Importantly, Fe3O4 nanoparticles displayed superparamagnetic behavior at 25 °C with saturation magnetization of 50 emu/g. Moreover, the catalytic activity of Fe3O4 nanoparticles was evaluated by the degradation of dyes (Rhodamine B: RhB, and Methylene blue: MB) in the presence of H2O2. According to those results, Fe3O4 nanoparticles could activate H2O2 and, thus, had a degradation efficiency of 98% and 80% for RhB and MB, respectively, in 120 min.