Efficient removal of hexavalent chromium from water and soil using magnetic ceramsite coated by functionalized nano carbon spheres

A magnetic ceramsite (MC) coated by nano carbon spheres (MCCS) was fabricated, and then the MCCS was stabilized and functionalized by polyethylenimine (PEI) to obtain a nanocomposite named as MCCSP. The nano carbon spheres (NCS) possessed plenty of amino and oxygen-containing groups (eOH, eCOOH) and distributed homogeneously on the surface of MC, meanwhile the size and dispersion of these NCS could be conveniently adjusted. MCCSP demonstrated a high adsorption capacity for Cr(VI) which could be then reduced to low toxic trivalent chromium (Cr(III)), and the obtained Cr(III) could be chelated on the surface of MCCSP by protonated amine groups. Importantly, the resulting MCCSP-Cr could be conveniently collected from water and soil by a magnetic separation system (MSS). Therefore, this work provides a promising approach to remediate Cr(VI)contaminated water and soil and may have a high application value.