Oscillations with a long periodical time observed in solute transport by diffusion combined with convection through a single hollow-fiber membrane

Solute transport by diffusion combined with convection through a single hol low-fiber membrane fixed on an axis of a circular tube was studied precisel y. Purified water and an aqueous solution of a solute were fed at constant flow rates into the circular tube and the lumen of the membrane, respective ly, and oscillations with a long periodical time were observed in the conce ntration of solution discharged from the lumen. Results obtained with varyi ng experimental conditions (different solutes, membranes and flow rates at the lumen inlet and outlet) suggest that the oscillations are related to so lute transport caused by convection flow through the membranes. (C) 2001 El sevier Science B.V. All rights reserved.