Removal of methylene blue from aqueous solutions by poly(acrylic acid) and poly(ammonium acrylate) assisted ultrafiltration

• Removal of MB was performed using polyelectrolyte enhanced ultrafiltration.
• Effect of anionic polyelectrolyte concentration on R% and J was evaluated.
• The decolourisation of MB depends of the salt concentration and pH.

Despite the numerous works dealing with the application of polyelectrolyte-enhanced ultrafiltration (PEUF) for the removal of micropollutants, its application for the treatment of dye effluent is very scarce. In the present study we investigated the recovery of methylene blue (MB), a phenothiazine cationic dye, by ultrafiltration with two anionic polyelectrolytes used as complexing agents. The ultrafiltration experiments were operated in batch mode with stirred cell equipped with 10,000 MWCO regenerated cellulose. Effects of operating conditions, e.g., transmembrane pressure, feed polyelectrolyte, feed dye solution, NaCl concentration, and pH on dye retention and permeate flux have been analyzed. High retention rate of dye in the order of 98% was obtained as a result of complexation between anionic polyelectrolyte and cationic dye. However the retention of the dye decreases as the salt concentration increases and pH decreases.