AC and DC-Currents for Separation of Nano-Particles by External Electric Field

Abstract

An attractive technique is carried out by electrical phenomena to demulsify benzene in water emulsion. In this study, non-uniform electric field is applied to remove benzene particles which have been transferred to the water (oil/water-emulsion). Electric current leads to move oil particles in emulsion contact each other and also create bigger oil drops by induction of negative charge, then the oil moves upward due to density difference and can be measured. Based on these experiments, about 80 % benzene demulsify from the emulsion in lower than 10 min, which indicates that the mutual contact of oil droplets through thin water layers in necessary for the rapid demulsification. All this evidence strongly suggests that the applied electric field causes the rearrangement of surface charges on oil droplets, which results in the reduction of the height of an energy barrier for the coalescence of the droplets. In the present paper, benzene is used as disperse phase and water is used as continuous phase. The effective benzene-particles sizes in water are determined by atomic force microscope (AFM) about 90 nm.