Removal of heavy metal ions by a chelating resin containing glycine as chelating groups

A porous chelating resin, crosslinked poly(glycidyl methacrylate-glycine) (PGLY), was synthesized through an epoxy group reaction of crosslinked poly(glycidyl methacrylate) with glycine for the removal of Cu(II), Ni(II) and Cd(II) from aqueous solutions. The interaction between a metal ion and chelating groups within PGLY was examined using FT-IR analysis. In single-metal ion solutions, all the adsorptions tended toward equilibrium at 40 min and the equilibrium adsorption capacities of PGLY were 1.22, 1.07 and 0.96 mmol/g for Cu(II), Ni(II) and Cd(II), respectively. Except pH > 4.0, as pH of the solution decreased the adsorption capacity of each metal ion decreased. After 15 cycles of adsorption–desorption operations, the re-adsorption capacities could attain 86–93% of initial values of uptake. When the pH of the mixture solutions were 2 or 2.5, the competitive adsorption tests confirmed this resin had good adsorption selectivity for the recovery of Cu(II) from Cu(II)/Ni(II) or Cu(II)/Cd(II) mixture.