Effect of Cross Flow Velocity, Feed Concentration, and Pressure on the Salt Rejection of Nanofiltration Membranes in Reactive Dye Having Two Sodium Salts and NaCl Mixtures: Model Application

In this study, effects of cross flow velocity, feed concentration, and pressure on the permeate flux and salt rejection were investigated by nanofiltration membranes. DS5 DK type nanofiltration membrane was tested and reactive orange 16 (RO16), reactive blue 19 (RB19) and NaCl were used in the experiments to prepare the synthetic reactive dye and salt mixtures. The study indicated that operating conditions are very important for both permeate fluxes and salt rejections during nanofiltration of dye and salt mixtures. Fluxes and salt rejections increased with increasing cross flow velocity. In addition, feed solutions in different reactive dye and salt concentrations, which affected the ionic strength and agglomeration of dye solutions, decreased the permeate flux values. In addition, author's previous model (Koyuncu, I.; Topacik, D. Effect of organic ion on the separation of salts by nanofiltration membranes. Journal of Membrane Science 2002, 195, 247-263.), which has been derived assuming the salt and dye concentrations on membrane surface, was applied to experimental results.