SYNOPSISThe effects of water-soluble polymers on the concentration and separation of the aqueous solutions of the metal ions have been studied. The separation of metal ions can be possible by ultrafiltration-complexation process. The effect of Dextran, which is a water-soluble polymer, on the concentration and separation of metal ions (Cu2+, Ni2+, Fe3+) have been investigated by using EC-PEG 4000 alloy membranes. The permeability of these membranes for metal ions has been recorded at constant pressure but different pH values. It has been noticed that the highest water-permeable membrane is also permeable towards Cu2+ and Ni2+, but has shown a considerable retention for Fe3+ as a result of the hydrolysis of Fe3+. The retentions of metallic ions and metallic-ion-Dextran couples have been determined at constant pressure but different pH and polymer concentration values. It has been shown that Fe3+/Ni2+ and Fe3+/Cu2+ couples can be separated by using Dextran. 0 1995 John Wiley & Sons, Inc.

SYNOPSISThe 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 a t constant pressure but at different p H values. The highest water-permeable membrane is also permeable for Cu2+ and Ni2+, but it shows a considerable retention for The concentration and separation of metal ions from their aqueous solutions by using semipermeable membranes can be realized by ultrafiltration.' In this method, the polymer must have high selectivity for the metal ion or ion group, high binding capacity, narrow molecular weight distribution, and high water-solubility properties.It is possible to form a complex between the polymer and the metal ion if the polymer shows a significant selectivity for the metal ion. Concentration and separation of metal ions can thus be achieved by complexing these species with a suitable watersoluble polymer. The principle of this process was first proposed by Michaek2* T o whom correspondence should be addressed. We attempted to concentrate Cu2+, Ni2+, and Fe3+ ions and to separate the metal ion couples from very dilute solutions by using PVA at varying pH and concentration values. Spectrophotometric data and ultrafiltration results were interpreted in terms of complexation reactions.

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