Preparation and characterization of magnetic nanomaterial and its application for removal of polycyclic aromatic hydrocarbons

Fe3O4@polyaniline, a Fe3O4-based magnetic core-shell material, was synthesized and its morphology and microstructure were characterized with transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and vibrating sample magnetometry. Polyaniline was modified onto the surface of Fe3O4 nanoparticles by a self-assembly method based on a two-step oxidative polymerization method. The new materials exhibited good adsorption to polycyclic aromatic hydrocarbons such as fluoranthene, pyrene and benzo[a]pyrene from environmental water samples due to the high affinities of polyaromatic hydrocarbons to polyaniline via pi-pi and van der Waals interactions. The experimental results indicate that the adsorption of polyaromatic hydrocarbons follows pseudo-second order kinetics and the adsorption isotherms conform to a Langmuir isotherm model. The thermodynamic parameters for polyaromatic hydrocarbons indicate that the adsorption process is spontaneous and endothermic in nature, but adsorption occurs via non-covalent interactions. This study indicated that the Fe3O4@polyaniline hybrid core-shell structure was proved to be a good adsorbent for polyaromatic hydrocarbons while exhibiting simple preparation, easy separation, low cost, high reusability and great potential applicability for removal of polyaromatic hydrocarbons from water.