Commercial, water-soluble poly(ethylenealt-maleic anhydride), P(E-alt-MAn), was quantitatively hydrolyzed by 0.2M NaOH to yield poly(ethylene-alt-maleic acid), P(E-alt-MAc). The polymer structure is confirmed by FT-IR spectroscopy. As the pH increases, metal ion affinity increases because the majority of the functional groups are present as carboxylate anions, which can form more stable complexes at a higher pH. By increasing the filtration factor, Z, metal ion affinity does not significantly decrease, which means that the ligand-metal interaction is strong and cannot be destroyed by washing with water at the filtration cell's pH. (c) 2006 Wiley Periodicals, Inc.