Electrostatic oil purification technology is considered to be one of the most promising technologies for high-precision purification of industrial oil such as hydraulic fluids. In practical applications

electrophoresis and dielectrophoresis(DEP) occurring in electrostatic oil cleaner results in removal of nano-micron contaminants. In this review

the authors outline the different types of electrostatic oil purifiers and the mechanism of oil purification

including the construction of reactor and influence of electric field type

and analyze their advantages and disadvantages on oil purification. Finally

a series of ideas for generating gradient electric fields are proposed

including filling with high dielectric media and using non-parallel electrode plates. In addition

the accelerated adsorption of neutral impurity molecules or polar colloidal contaminants by electrophoresis and DEP phenomenon is also analyzed.