부산대학교 도서관

Theoretical analysis and experiments are presented on filtration of liquids by means of the dielectrophoretic effect in pulsating and AC fields. Quite satisfactory results are obtained in the AC case at frequencies above 4 KHz, even for relatively conducting medium. It is also shown that as the force is time-dependent, allowance must be made for the interaction of the particles with the trapping surfaces. In recent papers 1,2 we extensively studied the possibility of liquid filtration by means of the dielectrophoretic effect, induced by applying a non-homogeneous field to the medium to be filtered. These studies, while demonstrating the overall advantages of the method, were confined to DC fields, in which the particle-trapping process is impeded as the conductivity of the medium increases. The study reported here showed that this difficulty can be overcome by recourse to time-dependent — pulsating or AC — fields (especially the latter). In addition, the time-dependent regime brought out phenomena which could not be followed under its DC counterpart — interalia, the interaction of the particles with the trapping surfaces, which is the main topic of this paper.