Glycidyl methacrylate based polymer resins with diethylene triamine tetra acetic acid functions for efficient removal of Ca(II) and Mg(II)

Crosslinked terpolymer beads prepared by suspension polymerization of glycidyl methacrylate (GMA) (0.4 mol), methyl methacrylate (MMA) (0.5 mol) and divinyl benzene (DVB) (0.1 mol) mixtures have been modified through epoxy functions in two steps: (i) by treating with excess of diethylene triamine (DETA); and (ii) by subsequent reaction with potassium chloroacetate. The resulting polymer possessing diethylene triamine tetra acetic acid (DTTA) functions (with degree of functionalization DF:1.70 mmol·g^-1) is an efficient sorbent for removal of Ca (II) and Mg (II) ions in ppm levels. Interestingly when the sodium form of the resin is used in relatively high concentrations (0.1 M) sorbed amounts will be 10-45% in excess of the theoretical capacity due to precipitation of the metal hydroxides on polymer particles beside chelation with the metal ions. Having EDTA-like chelating units, the polymer is able to absorb also heavy metal ions such as Fe (III), Zn (II), Cd (II), Pb (II), Ni (II), Cu ( II), Co (II) ions. Not having hydrolysable linkages, metal-free resins can be obtained by acid treatment (4 M HCl) without loosing its activity. The resin with DTTA functions seems to be applicable in large scale water softening processes.