The crosslinked poly[N-(3-dimethylamino)propylmethacrylamide] [P(NDAPA)] and poly[N-(3-dimethylamino)propyhnethacrylamide-co-acrylic acid] [P(NDAPA-co-AA)] were synthesized by radical polymerization. The resins were completely insoluble in water. The metalion-up-take properties were studied by a batch equilibrium procedure for the following metal ions: silver(l), copper(II), cadmium(H), zinc(II), lead(II), mercury(II), chromium(Ill), and aluminum(III). The P(NDAPA-co-AA) resin showed a lower metal-ion affinity than P(NDAPA), except for Hg(II), which was retained at 71% at pH 2. At pH 5, the resin showed a higher affinity for Pb(II) (80%) and Cu(II) (60%), but its affinity was very low for Zn(II) and Cr(III). The polymer ligand-metal-ion equilibrium was achieved during the first 20 min. By changing the pH, we found it possible to remove between 60 and 70% of Cd(II) and Zn(II) ions with (1M, 4M) HClO4 and (IM, 4M) HNO3. (c) 2006 Wiley Periodicals, Inc.