Magnetically Recyclable Fe3O4/GO-NH2/H3PMo12O40 Nanocomposite: Synthesis, Characterization, and Application in Selective Adsorption of Cationic Dyes from Water.

In this study, the PMo12O403- polyanion was immobilized chemically on amino functionalized magnetic graphene oxide nanosheets. The as-prepared ternary magnetic nanocomposite (Fe3O4/GO-NH2/H3PMo12O40) was characterized by powder X-ray powder diffraction (XRD), fourier transformation infrared spectroscopy (FTIR), Raman spectroscopy, energy dispersive spectroscopy (EDX), field emission scanning electron microscopy (FESEM), BET surface area measurements, magnetic measurements (VSM) and atomic force microscopy (AFM). The results demonstrated the successful loading of H3PMo12O40 (~36.5 wt.%) on the surface of magnetic graphene oxide. The nanocomposite showed a higher specific surface area (77.07 m2/g) than pure H3PMo12O40 (≤10 m2/g). The adsorption efficiency of this nanocomposite for removing methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) from aqueous solutions was evaluated. The nanocomposite showed rapid and selective adsorption for cationic dyes from mixed dye solutions. The adsorption rate and capacity of Fe3O4/GO-NH2/H3PMo12O40 were enhanced as compared with GO, GO-NH2, Fe3O4/GO-NH2, and H3PMo12O40 samples due to enhanced electrostatic attraction and hydrogen-bonding interactions. The nanocomposite is magnetically separated and reused without any change in structure. Thus, it could be a promising green adsorbent for removing organic pollutants in water.