POLYMER-METAL COMPLEXES OF N,N'-METHYLENE-BIS-ACRYLAMIDE (NNMBA)-CROSS-LINKED POLYACRYLAMIDE-SUPPORTED GLYCINES - EFFECT OF THE DEGREE OF CROSS-LINKING ON METAL-ION COMPLEXATION AND CONCENTRATION

Glycine functions were incorporated into 2-20 mol% N,N'-methylene-bis- acrylamide (NNMBA)-crosslinked polyacrylamides by transamidation with excess sodium salt of glycine. Complexation characteristics of glycine functions in different structural environments were investigated towa rds Co(II), Ni(II), Cu(II) and Zn(II) ions. The observed trend in comp lexation was found to be: Cu(TT) > Ni(II) > Co(II) > Zn(II). The polym eric ligands and metal complexes were characterized by various spectra l techniques. The polymeric ligands could be recycled several times an d the metal ion desorbed resins showed specificity to the desorbed met al ion than other metal ions. This originates from the development of certain 'pockets' left by the desorbed metal ion or the 'memory' of th e polymeric ligands for the desorbed metal ion. This lightly crosslink ed systems showed much faster rebinding kinetics. The conditions of me tal ion binding and rebinding were optimized to exploit the specific a nd selective separation of metal ions using metal ion desorbed systems . The specificity and selectivity characteristics depend on the degree of NNMBA crosslinking.