Preparation of magnetic Fe3O4/Au composites for extraction of benzo[a]pyrene from aqueous solution

•A efficient approach was designed for preparation of magnetic Fe3O4/Au composites.•The composites possessed good magnetic response property.•The composites could be used as adsorbent for rapid extraction of benzo[a]pyrene.•The adsorption kinetics, isotherms and mechanism were investigated.

The magnetic Fe3O4/Au composites have been synthesized by a specific strategy and used as adsorbent for extraction of benzo[a]pyrene from aqueous solution. The prepared materials were characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). Adsorption performances of the magnetic Fe3O4/Au composites are tested with extraction of benzo[a]pyrene from aqueous solution and the adsorption kinetics, isotherms and mechanism were investigate. The adsorption was relatively fast and the kinetics data were well fitted by the pseudo-second order model. The best interpretation for the equilibrium data was given by Freundlich model. The adsorption mechanism may be dominated by the electron donor–acceptor interactions between the π-system of benzo[a]pyrene (BaP) and aurum atom of the gold nanoparticles. Moreover, the high magnetic response property of the Fe3O4 core made the adsorbent easy to separation with the aim of an external magnet without additional centrifugation. The adsorption–desorption studies indicated that the magnetic Fe3O4/Au composites were able to conveniently regenerated and reused. Based on these, a rapid and efficient method for extraction and analysis BaP in real water sample was established.

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