Ultrafiltration rejection of dissolved ions using various weakly basic water-soluble polymers

The rejection of divalent metal ions including Cu2+ and Zn2+ from water in polymer-assisted ultrafiltration was studied. Three weakly basic water-soluble polymers: chitosan, poly(ethylenimine), and poly(diallyl dimethylammonium chloride) were selected, and the hydrophilic membrane Amicon YM10 (regenerated cellulose) was used. Experiments were performed as a function of solution pH. It was shown that a higher rejection of Cu2+ was obtained compared to Zn2+ as long as the pH was not far less than 7. The effect of added alkaline earth cation Mg2+ on metal rejection and filtration flux was examined. The regeneration of the three polymers from a retentate by electrolysis and acidification was finally evaluated.