Synthesis of Magnetic N‐Vinylformamide Grafted Starch and Its Application in Heavy Metals Adsorption

Abstract

AbstractUsing cyclohexanone and sodium bromate as initiators, N‐vinylformamide (NVF) is self‐polymerized and grafted onto the pregelatinized starch (PGS) to form NVF‐starch graft copolymer (SGC). Fe3O4 surface is coated by MnO2 formed by in situ chemical reaction between KMnO4 and MnSO4 to obtain modified nanoparticles (NFs). A novel M‐starch graft copolymer (M‐SGC) is combined from SGC and NFs in aqueous solution by sonication. The structures of SGC, NFs, and M‐SGC are characterized by FTIR, SEM, XRD, BET, and 1H‐NMR. The adsorption mechanism by M‐SGC is investigated by FTIR and XPS. The results show that M‐SGC has the ability to adsorb Cu2+, Ni2+, and Cr2O72− from aqueous solutions with high efficiency. Cu2+ and Ni2+ are removed by amide bond chelation and ion exchange of M‐SGC. The Cr2O72− is separated by chelation through turned to trivalent chromium. M‐SGC adsorbs 274.6 mg g−1 Cu2+ in 3.0 g L−1 copper solution, 8.92 mg g−1 Ni2+ in 0.5 g L−1 nickel solution, and 36.5 mg g−1 Cr2O72− in 1.2 g L−1 potassium dichromate solution. The adsorption experiments of M‐SGC has a good recyclability.