Combined adsorption and catalytic ozonation for removal of endocrine disrupting compounds over MWCNTs/Fe3O4 composites

Abstract MWCNTs/Fe 3 O 4 magnetic composites, combined adsorption and catalytic ozonation behavior, were synthesized by a hydrothermal process. The synthesized MWCNTs/Fe 3 O 4 composites were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), element analysis and Brunauer-Emmett-Teller (BET) surface area. The adsorption performance and catalytic activity of MWCNTs/Fe 3 O 4 for BPA removal in aqueous solution were evaluated. The results showed that the synthesized MWCNTs/Fe 3 O 4 exhibited an excellent adsorption ability and catalytic ozonation activity owning to its large specific surface areas, hollow tube channels and abundant surface oxygen-containing groups, leading to high adsorption for BPA and O 3 , high retention and utilization of O 3 molecules on the composites. In addition, the catalytic ozonation performance of MWCNTs/Fe 3 O 4 could be improved by increasing surface oxygen-containing groups to accelerate O 3 decomposition, thus producing more OH radicals. Moreover, BPA removal efficiency could be improved by increasing dose of catalyst, pH value and the concentration of humic acid (HA). The fluorescence spectra and OH radicals measurement displayed that HA could greatly increase OH radicals via inducing more surface oxygen-containing groups on the catalyst, thus, promoting BPA removal. Furthermore, MWCNTs/Fe 3 O 4 showed the great stability and durability during several reaction recycles.