A geometric model to predict protein retentions during skim milk microfiltration

Microfiltration membranes can retain dissolved proteins to some degree, as result of interactions with other components. This work presents a geometric model to describe the limiting transmembrane pressure, flux, and the transmission of dissolved proteins. The effects of temperature and membrane pore size are observed in other factors such as viscosity, membrane resistance and rate of mass transfer. The model could predict the experimental transmembrane flux values at different temperatures. With a decrease in temperature from 15 °C to 5 °C, the viscosity increased from 1.6 mPa s to 2.2 mPa s while the rate of mass transfer decreased with decreasing temperature of the same range from 0.9 × 10−6 m s−1 to 2 × 10−6 m s−1. With a change in temperature, there was insignificant difference between the transmission of whey proteins. The same was observed with different pore sizes. This confirmed the hypothesis that the concentration polarization layer that determines the protein transmission being a sieving layer at pressures higher than the limiting transmembrane pressure.