The effect of magnetic field on efficiency and fouling mechanisms during membrane clarification of pomegranate juice

Microfiltration can be used to clarify Pomegranate juice (PJ); however, it is fouled by charged particles. Magnetic field was coupled with microfiltration to reduce the membrane fouling. Results showed that magnetic field halved the total resistance; since, it increased the permeate flux. The most efficiency of application of the magnetic field in the membrane clarification was achieved at the high intensity of the magnetic field, low level of the feed flow rate and the direction of the magnetic field from the feed to the permeate side. Evaluation of the fouling mechanisms showed that with the increase in the intensity of the magnetic field, at the beginning of the process, the intermediate and standard blockings were dominant mechanisms, but over time, the formation of the cake became more important. Scanning electron microscope (SEM) showed that the layer of the cake deposited on the membrane surface in the absence of the magnetic field, inverse mode with the magnetic field, was very dense. On the other hand, the total monomeric anthocyanin content and the antioxidant activity of PJ increased; pH and total phenolic components were constant, and the total soluble solid content, the turbidity and the acidity were reduced.