ANALYSIS OF FILTRATION MECHANISM OF DEAD-END ELECTROULTRAFILTRATION FOR PROTEINACEOUS SOLUTIONS

Dead-end ultrafiltration with application of a d.c. electric field to reduce membrane fouling rates was conducted under constant pressure using protein (bovine serum albumin) solution. When electric fields were applied, the filtration rate was significantly increased over that in ordinary dead-end ultrafiltration by both electrophoretic motion of the solutes away from the cake surface and electroosmosis occurring in the filter cake. The improvement in filtration rate becomes more pronounced with increasing electric field strength. In addition, effects of such processing variables as the solution concentration, the pH of solutions and the applied filtration pressure on the performance of dead-end electro-ultrafiltration were examined. A mathematical model was developed to describe the processes occurring during dead-end electro-ultrafiltration, taking both electrophoretic and electroosmotic effects into account. The model accounted well not only for the dynamically balanced filtration rate but also for the variation in filtration rate with time.