Ultrafiltration of sugar cane juice for recovery of sugar: analysis of flux and retention

Raw sugar cane juice was pretreated by cold liming. Clarified juice was the n subjected to ultrafiltration (UF) in a stirred cell using three different membranes (Spectra For 10 K (M1) and 20 K (M3); commercial diffused cut-of f 15 K (M2) membranes). The filtration studies were carried out with the ai m of retaining the solids except the sugar compounds, present in juice as w ell as maximizing the flux. Permeate flux and retention of sugars as well a s total dissolved solids in permeate stream were measured. Performances of these membranes were evaluated in terms of permeate flux and its quality. I t was observed that the permeate flux obtained using M1 membrane was higher than M2 and M3 for most of the operating conditions. However, the retentio n of sugars was minimum for M3 membrane, which is desirable. A modified res istance-in-series model has been used to analyze both short and long term f lux decline behavior under various operating conditions. (C) 2001 Elsevier Science B.V. All rights reserved.