In silico separation of magnetic nanoparticles from linear flow: A parametric study

Abstract

Magnetic separation of nanoparticles from water offers a promising approach for advanced water treatment, particularly for removing contaminants bound to functionalized magnetic carriers. This study presents an in silico investigation of magnetic nanoparticles capture from linear laminar flow using permanent magnets, modeled with COMSOL Multiphysics. A coupled simulation framework combines multiphysics modules to simulate the trajectories of 100 non-interacting nanoparticles suspended in water. Parametric analysis focuses on the influence of magnet-to-pipe distance, flow rate, and nanoparticle magnetization. Recognizing that magnetic nanoparticles often exhibit reduced magnetization due to size, surface, and shape effects, simulations include various fractions of the saturation magnetization rather than assuming full saturation. Magnetic field gradients are computed to evaluate magnetic forces, which are balanced against hydrodynamic drag to determine particle trajectories and separation efficiency. Results show that proximity of the magnets and increased effective magnetization significantly enhance particle capture, while higher flow rates reduce separation efficiency. This study offers a comprehensive assessment of the magnetic and hydrodynamic factors governing magnetic nanoparticles removal in flowing systems. The findings inform the design of efficient, scalable magnetic separation systems for water purification and environmental remediation applications.