Continuous ion-exchange membrane electrodialysis of mother liquid discharged from a salt-manufacturing plant and transport of Cl- ions and SO4 2- ions

The permeate flux declination along an ultrafilter membrane is due mainly to the concentrationpolarization resistance increment and the decline in transmembrane pressure. It was found in previous works that the concentration polarization resistance could be reduced in a ring-rod tubular membrane ultrafilter using the turbulent behavior. In the present study, the performance was further improved by properly and gradually decreasing the baffled-ring distance along the cross-flow channel coupled with properly adjusting the number of baffled rings. This theoretical analysis is based on the mass and momentum balances as well as the application of the resistance-in-series model. The correlation predictions are confirmed with the experimental results for dextran T500 aqueous solution ultrafiltration.