| Abstract: | The concentration and separation of some metallic ions have been achieved by complexing these species with suitable macromolecules or with water-soluble polymers in ultrafiltration. The effect of water-soluble poly(vinyl alcohol) (PVA) on the concentration and separation of Cu2+, Ni2+, and Fe3+ ions have been investigated by using EC-PEG4000 alloy membranes in ultrafiltration experiments. The water permeability of the membranes has been measured at various pressures. The permeability of these membranes for metal ions, however, has been recorded at constant pressure but at different pH values. The highest water-permeable membrane is also permeable for Cu2+ and Ni2+, but it shows a considerable retention for Fe3+, probably as a result of the hydrolysis of Fe3+. The retentions of metallic ions and metallic ion-PVA couples have been determined at constant pressure but varying pH and polymer concentration values. It has been shown that Fe3+/Ni2+ pairs can well be separated by using PVA. © 1993 John Wiley & Sons, Inc. |
