Chelating magnetic copolymer composite modified by click reaction for removal of heavy metal ions from aqueous solution

• Magnetic copolymer beads were functionalized by azide–alkyne click reaction.
• The chelating beads showed excellent adsorption capacity for heavy metal ions.
• The beads possessed a sensitive magnetic response and could be repeatedly used.

Novel chelating magnetic copolymer beads in micron-size range were prepared by suspension polymerization and click reaction. The click chemistry was proposed as a tool for tuning the surface functionality of magnetic poly(vinylbenzyl chloride-co-styrene-co-divinyl benzene), M-PVBC, by a covalent attachment with propargyl alcohol via triazole formation. After click-coupling reaction, the changes in surface morphology and chemical functionality were examined by SEM–EDX and FT-IR, respectively. Adsorption characteristics for heavy metal were investigated by a batch adsorption in an aqueous system under different experimental conditions. The adsorption process was pH, concentration and time dependent. The maximum adsorption capacities of the chelating magnetic copolymer, M10-PVBC-C, for Zn(II), Cu(II) and Ni(II) in 500 ppm solutions were 67.29, 61.20 and 57.18 mg/g, respectively. Adsorption of Cu(II) ion, the model heavy metal ion, was well fitted to the Langmuir isotherm model. The magnetic chelating beads could be rapidly recovered from aqueous solution by an external magnetic field, regenerated and reused for 5 cycles without significant lost in adsorption capacity. The results of this work indicated that the surface functionalization by click reaction could be a simple and suitable method for the preparation of polymeric adsorbents for an effective removal of metal ions from aqueous solution.