Facile synthesis of multiwall carbon nanotubes/iron oxides for removal of tetrabromobisphenol A and Pb(ii)

Abstract

A one-step thermal decomposition strategy, in which a novel reductant participated, was developed to prepare superparamagnetic nearly cubic monodisperse Fe₃O₄ nanoparticles loaded on multiwall carbon nanotubes (MWCNTs/Fe₃O₄). Subsequently, the as-prepared MWCNTs/Fe₃O₄ nanocomposites were modified with 3-aminopropyltriethoxysilane (APTS) (MWCNTs/Fe₃O₄–NH₂). The materials were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), vibrating sample magnetometry (VSM) and the BET surface area method. The results indicated that superparamagnetic Fe₃O₄ nanoparticles were successfully loaded onto the surface of the MWCNTs, and APTS was also modified on the MWCNTs/Fe₃O₄ magnetic nanocomposites. The two as-prepared magnetic nanocomposites were used as adsorbents to remove tetrabromobisphenol A (TBBPA) and Pb(II) from wastewater. The adsorption kinetics and adsorption isotherms of TBBPA and Pb(II) on the two as-prepared adsorbents were studied at pH 7.0 and 5.3, respectively. It was revealed that MWCNTs/Fe₃O₄–NH₂ performed better than the MWCNTs/Fe₃O₄ nanocomposites for the adsorption properties of TBBPA and Pb(II). After adsorption, both adsorbents could be conveniently separated from the media by an external magnetic field within several seconds, and regenerated in 0.1 M NaOH solution.