Identification of optimal membrane morphological parameters during microfiltration of mosambi juice using low cost ceramic membranes.

摘要

In this work, experimental investigations were carried out for the identification of optimal membrane morphological parameters (pore size distribution, average pore size and porosity) during microfiltration (MF) of mosambi juice using low cost ceramic membranes. Four different low cost ceramic membranes with different pore diameters (dm) and porosities ( epsilon) were subjected to MF studies to evaluate the effect of dm and epsilon on permeation characteristics (permeate flux and juice quality) of centrifuged mosambi juice (CJ) and enzyme treated centrifuged mosambi juice (ETCJ). Subsequently, a convenient factor namely effective permeable area factor ( epsilonmdm2) was evaluated to provide greater insights in the fouling phenomena. Various physio-chemical properties such as colour, clarity, pH, citric acid content, density, total soluble solid (TSS) and alcohol insoluble solids (AIS) were measured for both feed and permeate juice samples to evaluate the effect of epsilonmdm2 on juice quality. Typical permeate fluxes were observed to vary from 5.78 x 10-6 to 13.45 x 10-6m3/m2s for CJ and 14.07 x 10-6 to 60.64 x 10-6m3/m2s for ETCJ at 82.7kPa ( DeltaP) for different membranes whose epsilonmdm2 varied from 0.249 to 0.783 mum2. Among different membrane pore blocking models, flux decline by cake filtration was found to be the best fitted model. The cake filtration model constant (kc) was found to vary with DeltaP and epsilonmdm2 and was empirically correlated. Phenomenological models were proposed to illustrate the dependency of total hydraulic resistance of membrane on epsilonmdm2, DeltaP and time (t). Based on experimental as well as theoretical investigations, membranes with epsilonmdm2 up to 0.443 mum2 for CJ and 0.294 mum2 for ETCJ and a DeltaP of 82.7kPa were recommended for MF of mosambi juice.