High-Throughput Synthesis of Superparamagnetic Fe3O4 Nanoparticles in Chaotic Convection Mode

Conventional batch reactors are difficult to fabricate high-quality superparamagnetic Fe₃O₄ nanoparticles at high throughput due to their high energy consumption and low mixing efficiency. We designed a four-stage oscillating feedback micromixer (FOFM) to achieve efficient mixing and mass transfer at high throughput. The FOFM can induce strong chaotic convection, resulting in a uniform concentration field and a narrow residence time distribution. High-quality superparamagnetic Fe₃O₄ nanoparticles were successfully synthesized in the FOFM using a microemulsion method. Even at a high throughput of 155 mL/min (Q_total), the synthesized Fe₃O₄ nanoparticles had an average particle size of 8.98 nm, a particle size distribution of 3–18 nm, and a saturation magnetization of 66 emu/g, and the productivity could reach 63.2 g/h which was three times higher than that of the conventional batch reactor. The FOFM has been proven to have great application potential in the synthesis of high-throughput and high-quality nanoparticles.