Cu(II), Zn(II), Co(II) and Pb(II) removal in the presence of the complexing agent of a new generation

In this study, the use of the strongly basic polystyrene and polyacrylate anion exchangers to remove heavy metal ions Cu(II), Zn(II), Co(II) and Pb(II) in the presence of a new generation chelating agent from wastewaters was evaluated. The increase of the sorption capacity of heavy metal ions in the presence of N,N-bis(carboxymethyl)glutamic acid (GLDA) could be achieved after optimalization of phase contact time (1–180 min), shaking speed (140–180 rpm), concentration (7.5 × 10−4–2.5 × 10−2 mol/L), resin dosage (0.1–0.7 g), pH (2–12), temperature (293–333 K) and the presence of interfering ions (Ca(II), Mg(II), Cl−, SO42−, and NO3−). The experimental data were analysed using the sorption kinetic models viz., the Lagergren, Ho and McKay, Elovich, Weber and Morris. In the M(II)–GLDA = 1:1 system, the heavy metal ion sorption reached up to 56.67 mg/g for Cu(II) and 38.39 mg/g for Zn(II) on Amberlite IRA 402 and up to 51.10 mg/g for Cu(II) and 43.09 mg/g for Zn(II) on Amberlite IRA 458. The equilibrium sorption studies of Cu(II) and Zn(II) complexes with GLDA have been described by the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models.

Research Highlights
► IRA 402 and IRA 458 are effective for removal of heavy metal complexes with GLDA.
► GLDA is a good complexing agent in sorption of heavy metal ions.
► Sorption process depends on pH, contact phase time and temperature.
► Affinity series of M(II)–GLDA = 1:1 was found: Pb(II) > Cu(II) > Zn(II) > Co(II).