Changes in blocking mechanisms during membrane processing of pomegranate juice

P>The effect of pressure, velocity, pretreatment, membrane type and pore size on fouling mechanisms were evaluated. Pomegranate juice was treated with polyvinylidene fluoride (PVDF) 0.22 mu m and mixed cellulose ester (MCE) 0.1 mu m at different pressures. Cake formation which was the dominant mechanism was formed in the first stages of process and, as the filtration proceeded, intermediate, standard, and complete blocking, respectively occurred at higher pressure (5 kPa). At lower pressure (0.5 kPa) the last mechanism did not occur. Results showed that cake formation was the only mechanism in MCE 0.22 mu m, however, others occurred with MCE 0.1 mu m and PVDF 0.22 mu m. Using MCE 0.22 mu m prior to MCE 0.025 mu m can reduce the role of cake formation in pore blocking. Evaluation of the impact of velocity showed that at the higher velocity (0.53 m s-1) the complete blocking occurred faster than at the lower velocity (0.09 m s-1).