Crossflow membrane filtration enhanced by an external DC electric field:: A review

Techniques for fouling prevention in membrane filtration are needed. This paper reviews the process design, theory and some applications of crossflow membrane filtration enhanced by a DC electric field. An electric field can be applied across the membrane or the membrane itself can be the electrode. The performance of the filtration process is, in both cases, primarily improved due to electrophoresis. Electro-osmosis was found to be significant in some cases when an electric field was applied across the membrane. The theory of electrically enhanced crossflow membrane filtration is quite complex and there is no generally accepted model describing this process. Significant enhancement of the flux compared with the flux with no electric field has been found in the filtration of particles or colloids with high electrophoretic mobility using a pressure at which the cake was formed without an electric field and an electric field strength at which the net particle migration was away from the membrane. Apart from enhancement of the flux, the quality of the permeate has been found to improve by applying an electric field.