Influence of an Electric Field on Filtration in a Filter Press

Abstract

The need to dehydrate finely dispersed products is increasing worldwide. The electrofiltration potential increases with the particle surface area. Therefore the combination of mechanical and electrical filtration seems to be an effective method to enhance filtration kinetics. The attempts at pressure electrofiltration attempted in this work showed, that the residual moisture could only be lowered slightly by the electrical field, which itself is due to the electrolytic gas generated.

Pressure electroosmotic dewatering with continuous removal of electrolysis products

“…The processes investigated utilising an electric field include electrosedimentation to enhance sedimentation (Shirato et al, 1979); electrofiltration to enhance filtration or to reduce membrane fouling in crossflow filtration (Yukawa et al, 1976;Visvanathan and Ben Aïm, 1989;Wakeman and Sabri, 1995;Akay and Wakeman, 1997;Wakeman, 1998;Weber and Stahl, 2002a), and more recently electrowashing to remove specific solutes in porous media (Ghirisan et al, 2002;Tarleton et al, 2003). However, most research has concentrated on pressurised electroosmotic dewatering (PED), that is, the application of a DC electric field during the expression of formed cakes or porous media (Sprute and Kelsh, 1980;Lockhart, 1983;Iwata et al, 1991;Barton et al, 1999;Weber and Stahl, 2002b). Macroscopic modelling efforts have been attempted to analyse PED behaviour in saturated water media.…”

Chitosan Based Membranes for Separation, Pervaporation and Fuel Cell Applications: Recent Developments

“…The use of electric field in UF goes back to the first study carried out by Bechhold by imposing electric field in UF and utilized a combination of electro-osmosis and electrophoresis to purify colloids in an apparatus he called an 'electro-ultrafiltration' (EUF) [81]. EUF is an effective method to decrease gel layer formation on the membrane surface and to increase the filtration flux, owing to electro-kinetic phenomena such as electrophoresis and electro-osmosis [81][82][83][84][85][86]. Basic principle of EUF is presented in Fig.4.…”

“…This method is best suited for the separation of protein since its surface charge changes according to the solution pH [87][88][89][90][91][92][93][94][95][96][97][98][99][100][101][102][103]. As biological products like proteins and peptides are sensitive to shear stress and temperature, the coupled effects of electric field and pressure served as an additional driving force for the separation, which is an interesting way to improve the membrane permeates flux without increasing the shear stress [81,102,103]. Since proteins carry a net electrical charge, an electrical field may be used to reduce the influence of polarized layer.…”

Electrically Enhanced Washing of Ionic Species from Fine Particle Filter Cakes

“…The SO 4 2-and Cl -ions, along with the added NO 3 -ions, discharging in the wash liquor were detected using liquid chromatography. Examples of the anion concentration variations with time are plotted in Figure 9 for both the no field case and an applied potential of 20 V. The results indicate how nitrate ions were marginally more difficult to remove in the wash liquors and more marked differences were observed with the application of the electric field.…”

“…The processes investigated include electrofiltration, where a DC electric field is applied during deadend cake formation [e.g. [2][3][4] and the reduction of membrane fouling during crossflow filtration [e.g. [5][6][7][8][9][10].…”