Cross-linked PS-DVB/Fe3O4 microspheres with quaternary ammonium groups and application in removal of nitrate from water

Cross-linked PS-DVB/Fe3O4 microspheres (PFM-3) have been successfully synthesized by a new magnetic colloid swelling polymerization method and further functioned by alternatively using methylamine and 1,4-butanediol diglycidyl as monomers to build a branching polymer with quaternary ammonium groups. The characterization of PFM has been performed by XRD, FT-IR, SEM, TEM and BET surface area analyses. The results showed that PFM-3 possessed a high ion adsorption capacity (149.25 mg g−1) and could adsorb nitrate ions from water efficiently. The material also showed excellent reusability (after washing with sodium chloride, the absorption capacity was little reduced). More importantly, the magnetic microspheres could be removed from waste water easily via introducing an external magnetic field, which made the discoveries in this study provide an effective and environmentally friendly approach for fast removal of nitrate from waste water.