Synthesis of iron oxide nanoparticles in a continuous flow spiral microreactor and Corning® advanced flow™ reactor

Abstract

In the present work, synthesis of iron oxide nanoparticles (NPs) using continuous flow microreactor (MR) and advanced flow™ reactor (AFR™) has been investigated with evaluation of the efficacy of the two types of MRS. Effect of the different operating parameters on the characteristics of the obtained NPs has also been investigated. The synthesis of iron oxide NPs was based on the co-precipitation and reduction reactions using iron (III) nitrate precursor and sodium hydroxide as reducing agents. The iron oxide NPs were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and X-ray diffraction (XRD) analysis. The mean particle size of the obtained NPs was less than 10 nm at all flow rates (over the range of 20-60 ml/h) in the case of spiral MR, while, in the case of AFR™, the particle size of NPs was below 20 nm with no specific trend observed with the operating flow rates. The XRD and TEM analyses of iron oxide NPs confirmed the crystalline nature and nanometer size range, respectively. Further, magnetic properties of the synthesized iron oxide NPs were studied using electron spin resonance spectroscopy; the resonance absorption peak shows the g-factor values as 2.055 and 2.034 corresponding to the magnetic fields of 319.28 and 322.59 mT for MR and AFR™, respectively.