Physico-magnetic properties and dynamics of magnetite (Fe3O4) nanoparticles (MNPs) under the effect of permanent magnetic fields in contaminated water treatment applications

•Study on magnetite nano-particles agglomeration and magnetic map generation.•Understand the dynamics of magnetite nano-particles under an external magnetic field.•Trajectories of the larger particles converge more rapidly towards the magnet.•A global particles’ removal of ∼ 90% was observed for aggregate diameters > 1.2 µm.•Obtained data are useful for scaling-up and pilot-scale future practical application.