Gómez-Pastora Jenifer, Wu Xian, Sundar Neeraja, Alawi Jamal, Nabar Gauri, Winter Jessica O, Zborowski Maciej, Chalmers Jeffrey J
William G. Lowrie Department of Chemical and Biomolecular Engineering, The Ohio State University, 320 Koffolt Laboratories, 151 West Woodruff Avenue, Columbus, OH 43210, USA.
Department of Biomedical Engineering, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA.
Sep Purif Technol. 2020 Oct;248. doi: 10.1016/j.seppur.2020.117012. Epub 2020 May 4.
Superparamagnetic iron oxide nanoparticles (SPIONs) are employed in multiple applications, especially within medical and chemical engineering fields. However, their magnetic separation is very challenging as the magnetophoretic motion is hindered by thermal energy and viscous drag. Recent studies have addressed the recovery of SPIONs by a combination of cooperative magnetophoresis and sedimentation. Nevertheless, the effect of horizontal, high fields and gradients on the vertical sedimentation of SPIONs has not been described. In this work, we report, for the first time, the magnetically facilitated sedimentation of 5 nm particles by applying fields and gradients perpendicular to gravity. The magnetic field was generated by quadrupole magnetic sorters and the process was measured with time by tracking the concentration along the length of a channel contacting the 5 nm SPIONs within the quadrupole field. Our experimental data suggest that aggregates of 60-90 particles are formed in the system; thus, particle agglomeration by dipole-dipole interactions was promoted, and these clusters settled down as a result of gravitational forces. Multiple variables and parameters were evaluated, including the initial SPION concentration, the temperature, the magnetic field and gradient and operation time. It was found that the process was improved by decreasing the initial concentration and the temperature, but the magnitude of the magnetic field and gradient did not significantly affect the sedimentation. Finally, the separation process was rapid, with the systems reaching the equilibrium in approximately 20 minutes, which is a significant advantage in comparison to other systems that require longer times and larger particle sizes.
超顺磁性氧化铁纳米颗粒（SPIONs）有多种应用，尤其在医学和化学工程领域。然而，它们的磁分离极具挑战性，因为热能耗散和粘性阻力会阻碍磁泳运动。最近的研究探讨了通过协同磁泳和沉降相结合的方法来回收SPIONs。尽管如此，水平强磁场和梯度对SPIONs垂直沉降的影响尚未见报道。在这项工作中，我们首次报告了通过施加垂直于重力的磁场和梯度来实现5纳米颗粒的磁促沉降。磁场由四极磁选器产生，通过跟踪四极场内与5纳米SPIONs接触的通道长度上的浓度随时间来测量该过程。我们的实验数据表明，系统中形成了由60 - 90个颗粒组成的聚集体；因此，通过偶极 - 偶极相互作用促进了颗粒团聚，并且这些聚集体在重力作用下沉降。评估了多个变量和参数，包括初始SPION浓度、温度、磁场和梯度以及操作时间。结果发现，降低初始浓度和温度可改善该过程，但磁场和梯度的大小对沉降没有显著影响。最后，分离过程迅速，系统在大约20分钟内达到平衡，与其他需要更长时间和更大粒径的系统相比，这是一个显著优势。
