Effect of organic ion on the separation of salts by nanofiltration membranes

The aim of this study is to investigate the transport mechanism of NaCl thr ough nanofiltration membranes in mixed solutions. A model based on the Spie gler-Kedem and Perry-Linder models has been developed. Concentration polari zation effects of an organic ion and NaCl were not included in the previous studies. The effects of concentration polarization on salt removal were ad ded to the model. Reactive Black 5 (RB5) was used as an organic ion in the rejection of NaCl by DS5 membrane in all experimental runs. Different conce ntrations of RB5 and NaCl have been studied and a coefficient of the gel po larization effect of dye on salt removal (alpha) was defined depending on m olar concentration ratios of dye and NaCl. Experimental and calculated resu lts were shown to be in good agreement. (C) 2002 Elsevier Science B.V. All rights reserved.