Abstract: In this study, our objective was to quantify the capacity of a ceramic microfiltration (MF) membrane with a pore size of 200 nm to remove whey proteins, lactose, ash and calcium from skim milk. Skim milk was concentrated three times by microfiltration at 50 ℃, and then the resulting retentate was diluted to the original volume followed by three-fold concentration under the same conditions as for skim milk. The same treatment was performed on the retennate obtained from the second microfiltration. During the whole process, the cumulative removal percentages of α-lactalbuminn, β-lactoglobulin, lactose, ash and calcium calculated from the three filtrates obtained were 79.27%, 71.64%, 85.81%, 62.16%, and 35.64%, respectively. After the second filtration, the pure water flux of the membrane was reduced 89.27%, and the membrane flux was recovered to 99.07% of the initial level after cleaning the membrane with 2% NaOH and 0.5% nitric acid solution.

Key words: microfiltration, ceramic membrane, removal rate, membrane flux