Effects of operating parameters on fouling mechanism and membrane flux in cross-flow microfiltration of whey

In this paper, the dependency of permeate flux decline on operating parameters in cross-flow microfiltration of whey at constant operating pressure was studied. The governing fouling mechanisms and the effect of operating conditions on these mechanisms were investigated using linear forms of classic models as well as two-phase combined fouling models. A microfiltration set-up with flat module and Polyethersulfone (PES) membrane with 0.45 μm mean pore size was used. The results showed the positive effect of Reynolds number and operating pressure toward an optimum value of permeate flux. The optimum condition in this study was the highest Reynolds number (Re = 2500) and operating pressure (P = 1.5 bar). By classic models, for almost all experiments, flux decline was consistent with the “Standard blocking” model during the earlier stages and with the “Cake filtration” model during the later stages of filtration. Agreement with the “Cake filtration” model improved with increasing the operating pressure. In combined models, “Complete blocking–Cake filtration” and “Intermediate blocking–Cake filtration” were the best governing models in this system, but only at low Reynolds numbers and high operating pressures.

Research Highlights
► High Reynolds number and an optimum operating pressure increase permeate flux.
► Effect of Reynolds number is much more significant than the operating pressure.
► By classic models, flux decline was consistent with the SBM followed by CFM.
► In combined models, "CBM -CFM" and "IBM -CFM" models were the best governing models.