A Study on Stability of Magnetite Nanoparticles Suspension in Water by Zeta Potential Measurements

Abstract The paper presents an experimental research on the stability of an aqueous suspension containing 35% magnetite nanoparticles (MNPs) using the zeta potential measurement method. The main objective of this study is to determine the variation of zeta potential as function of the suspension’s alkalinity. By charging the surfaces of magnetite nanoparticles with negative hydroxyl groups, they produce electrostatic repulsion between magnetite nanoparticles and prevent short- and medium-term magnetic agglomeration and sedimentation. Alkalinising together with ultrasonication treatment are effective methods for stabilising magnetite nanoparticles suspensions used as ferrofluids.