(152c) Magnetophoretic Migration of Fe3O4 Nanoparticles Under Different Magnetic and Flow Field Conditions

Superparamagnetic iron oxide nanoparticles (SPIONs) are commonly used in chemical and biomedical engineering applications like biosensing, targeted drug delivery, bio-detection, and wastewater management. The motion of magnetic nanoparticles and colloids in a solution under the influence of magnetic field gradients, called magnetophoresis, is an essential step in magnetic separation technology. Although recent studies have shown that relatively small magnetic gradients (< 100 T/m) can provide fast magnetophoretic separation [1,2], the process still faces challenges due to the impending effects of thermal energy and viscous drag. This study aims to comprehensively investigate the effects of key variables on the magnetic separation of 10-30 nm SPIONs in biocompatible solutions and optimize their separation by identifying a proper combination of variable values. A quadrupole magnetic sorter (QMS) was utilized to create a horizontal magnetic field, and the process was monitored by tracking the SPIONs concentration along the length of a channel within the quadrupole field. Concentration profiles were estimated using grayscale measurements, and various variables were evaluated, such as initial SPION concentration, particle size, temperature, pH, and magnetic exposure time. Each combination of variable values was then characterized using two dimensionless quantities, the aggregation parameter (N*) and the magnetic Grashof number (Gr_m), which related to the existence or absence of particle-particle and particle-fluid interactions, respectively. By assessing the separation kinetics of SPIONs with varying sizes, this study can provide valuable insights for both engineering and biomedical applications and offer a cost-effective alternative to high-gradient/electromagnetic separation devices. The results of this study can be useful in the development of magnetic separators.