Synthesis of Aggregation-Free Iron Metal Particles Using Amylopectin and Amylase in a Basic Aqueous Solution

Iron metal particles (IMPs) have been used in various magnetic applications. Although IMPs can be synthesized using chemical reduction processes, they often experience problems such as aggregation and coalescence, which result in poor physical and magnetic properties. In this study, IMPs were synthesized in a basic aqueous solution using a chelating agent, iminodiacetic acid. By adding 0.1 wt% amylopectin to the solution as a gelling agent, highly spherical, aggregation-free IMPs were successfully synthesized with a particle size of 0.55 µm. Furthermore, the residual amylopectin on the resulting IMP surfaces was successfully removed by utilizing the enzymatic reaction with amylase. The amylase treatment at pH 6.9 completely removed the amylopectin without the oxidative corrosion of the IMPs, even though the treatment occurred in the aqueous phase. Finally, the saturation magnetization of the IMPs synthesized in this study reached approximately 120 emu/g.