Unraveling the intrinsic enhancement of fluorine doping in the dual-doped magnetic carbon adsorbent for the environmental remediation.

Abstract

Heteroatom doping endows magnetic carbons with unique electronic features and rich surface chemistry, significantly enhancing their adsorption performances for the environmental remediation. In this work, fluorine and nitrogen co-doped magnetic nanocarbon fibers (FN-MCFs) were prepared via a facile carbonization method combined with electrospinning procedure. FN-MCFs were used as adsorbents for Cr(VI) removal, displaying a remarkable activity with as high as 153.61\u202fmg/g and 0.58\u202fmg/m2 of the Cr(VI) removal ability. F and N co-doping in magnetic nanocarbon fibers offered a higher specific surface area and disorder degree in graphite layer, therefore providing more active sites on the adsorbents surface. The electrostatic adsorption and reduction reaction between the Fe0, Fe2+ nanoparticles or edge carbons and Cr(VI) ions played significant roles in the adsorption process, which was believed to be facilitated by F and N co-doping. It was found that chemical adsorption was the main process in this work. Moreover, the adsorption capacity of FN-MCFs was majorly influenced by the doping level or doping type. F doping was found to be more important than N doping for the Cr(VI) removal in the dual-doping system. In addition, the excellent reusability of the FN-MCFs was observed.