Poly (styrene sulfonamides) with EDTA-like chelating groups for removal oftransition metal ions

Chlorosulfonated styrene-divinyl benzene (10%) resin beads (420-590 mu m), when treated with an excess of triethylene tetramine (TETA), give a corresp onding polymeric sulfonamide with three amine functions. The free amine fun ctions of the resin were carboxymethylated almost quantitatively by reactin g with 20% excess of potassium chloroacctate in aqueous solution. The resul ting resin with iminoacetic acid functions showed rapid chelating abilities for transition metal ions such as Zn (II), Cd (II), Cu (EI), Ni (II), Co ( II), and Fe (III) ions. At the neutral pi-Is the chelating resin was able t o reduce the metal ion concentrations lower than 1 ppm in about 15 min of t he contacting time. Interestingly, when the resin was used in sodium form, metal binding capacities were higher than the theoretical capacity (1.66 mm ol.g(-1)), due to simultaneous precipitation of the transition metal hydrox ides on bead particles. The resin samples loaded with metal ions can be reg enerated more than 10 times by simple acid-base treatments, without activit y loss. (C) 2000 John Wiley & Sons, Inc.