The use of flow-field flow fractionation as a process control tool for membrane filtration in water treatment

In this paper, we discuss two methods to predict filtration characteristics of a given feed water with a given membrane in the application of dead-end ultrafiltration. The first method aims to determine the critical flux for irreversibility: The flux below which fouling built up during filtration is completely removed by backwashing. The critical flux and filtration behavior in general, were strongly influenced by the presence of an electrolyte in the solution. The second method is flow field-flow fractionation coupled to multi angle light scattering (flow FFF). We show that flow FFF can be used to determine particle-membrane interactions and particle size and molar mass distributions of a complex, model solution. The results of flow FFF were used to explain the filtration results obtained with the critical flux method for the sodium alginate in the presence and absence of salt.