Metallic iron nanoparticles intensified production by spinning disk reactor. Optimization and fluid dynamics modelling

The aim of this work was to investigate the optimization of iron nanoparticles production by spinning disk reactor. The influence of the two main operating parameters, i.e. rotational velocity and feed injection point position was investigated through evaluating the particle size distribution, the X-Ray powder diffraction spectra and metallic iron percentage production. Results showed that increasing both rotational velocity and the distance of reagents injection feed points from the disk centre led, to the production of metallic iron nanoparticles characterized by lower mean size. In particular, the optimal rotational velocity was found to be 1400 rpm whereas the optimal distance of injection feed point from disk centre was found to be 3.5 cm. According to these operating parameter values it was possible to obtain monodisperse nanoparticles, characterized by a mean size of 28 ± 2.1 nm and a production in the range 0.24–24 kg/day depending on the initial Fe(II) concentration. The results were then interpreted in light of three fluid dynamics models able to simulate the rotating thin liquid film on the surface of the spinning disk reactor. The applicability of Nusselt model was also investigated and discussed.