Iron oxide (IO) nanoparticles consist of maghemite (Fe2O3) and/or magnetite (Fe3O4) with diameters between 1 and 100 nanometers and show unique properties when compared to traditional materials. For instance, the surface area to volume ratio increases significantly for nanoparticles, allowing for a considerably higher binding capacity and excellent dispersibility in solutions for better contact with reactants. More importantly, when the size of magnetic nanoparticles is small enough (3-30 nm), they display superparamagnetism, meaning that their magnetization appears to be zero without an external magnetic field and that they can be magnetized by an external magnetic source. This property provides additional stability for magnetic nanoparticles in solutions. IO nanoparticles have attracted extensive interest due to their superparamagnetic properties and their potential applications in many fields
