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