Study on the inhibitory behavior of high-voltage electric field on the agglomeration and sedimentation of nanoparticles in suspension

Abstract

Nanoparticles can improve the heat transfer effect of fluids, however, they are difficult to dissolve in the base fluid and are prone to fouling, agglomeration and sedimentation during flow, which affects their efficient heat transfer characteristics. In this paper, the inhibitory effect of high-voltage electric field on the agglomeration and deposition of TiO2 nanoparticles in suspension was comparatively studied by comprehensive gravity sedimentation, spectrophotometer, particle size analysis, and zeta potential method. Studies have shown that the absorbance of suspensions is basically the same in neutral and acidic environments. However, in a highly alkaline environment, the agglomeration rate of nanoparticles increases significantly, resulting in a decrease in the absorbance of the suspension. The high-voltage non-uniform electric field generated by the active Cu rod electrode can effectively inhibit the agglomeration of TiO2 nanoparticles. However, the suppression effect of an external electric field is not necessarily the higher the voltage, the better. Different nanomaterials have different critical voltages. The high-voltage electric field of 1 kV has the best inhibitory effect on the agglomeration and deposition of TiO2 nanoparticles. An in-depth analysis of the mechanisms of the movement and agglomeration of TiO2 particles in suspension under high-voltage electric field excitation was conducted. The result shows that the agglomeration and sedimentation of particles in suspension depend on the Zeta potential of the nano particles. The higher the absolute value, the more stable the dispersion system is.