CONCENTRATION POLARIZATION AND FOULING DURING ULTRAFILTRATION OF COLLOIDAL SUSPENSIONS AND HYDROPHOBIC SOLUTES

Flux reductions experienced during ultrafiltration are due either to c oncentration polarization or fouling. It is usually difficult to disti nguish between these two phenomena, but by using a turbulence-promotin g module it is possible to determine the reversibility of a flux reduc tion, and thus distinguish between concentration polarization and foul ing. By using a turbulence-promoting module, it is also possible to di stinguish between different cases of fouling. In this paper, fouling c aused by the deposition of material at the surface of the membrane is illustrated by results from tests with a silica sol, and fouling due t o interactions in the membrane matrix is illustrated by results from u ltrafiltration of a low-molecular organic solute.