PVBC microspheres tethered with poly(3-sulfopropyl methacrylate) brushes for effective removal of Pb(II) ions from aqueous solution

A novel pH-sensitive polystyrene (PS)-type resin was developed by grafting of poly(3-sulfopropyl methacrylate) (PSPMA) brushes onto a cross-linked poly(vinylbenzyl chloride) (PVBC) microsphere via surface-initiated atom transfer radical polymerization (ATRP), and was further utilized as a highly efficient and recyclable sorbent to remove Pb(II) ions from aqueous solutions. The as-synthesized PSPMA-grafted PVBC microspheres were characterized by ATR-FTIR, XPS and SEM. Batch adsorption results revealed that the solution pH had an evident effect on the adsorption capacity of the PSPMA-grafted microspheres towards Pb(II) ions with an optimal sorption pH of above 5.0. The PSPMA-grafted microspheres had rapid adsorption kinetics of Pb(II) ions to reach adsorption equilibrium within 60   min. The Langmuir-fitted adsorption isotherms at pH 5.0 with an initial Pb(II) concentration range of 0.12–0.97   mmol   L −1 (i.e. 50–200   mg   L −1 ) revealed a maximum capacity of Pb(II) ions of 0.82   mmol   g −1 . The calculated thermodynamic parameters demonstrated an endothermic and spontaneous adsorption process of Pb(II) ions on the PSPMA-grafted microspheres. With the inherent stability, high adsorption capacity and good regenerability, the PSPMA-grafted PVBC microsphere resin provides a novel promising PS-type adsorbent for effective removal of heavy metal ions from aqueous solution.