Synergistic effect of iron doped ordered mesoporous carbon on adsorption-coupled reduction of hexavalent chromium and the relative mechanism study

In this study, a magnetic iron nanoparticles doped ordered mesoporous carbon (Fe/CMK-3) was successfully prepared for highly effective removal of Cr(VI). The resultant carbon material maintained ordered mesostructure, high surface area of 679.4 m(2) g(-1) with 4.42 wt% magnetic nanoparticles (Fe-0, Fe3O4 and lambda-Fe2O3) inside, and excellent magnetic property. Batch experiments were conducted to investigate the removal performance. Fe/CMK-3 exhibited higher Cr(VI) removal efficiency (similar to 97%), broader pH scope of application and easier separation compared with pristine ordered mesoporous carbon (CMK-3). The kinetics data were well described by pseudo-second-order kinetic model, and Langmuir model fitted the sorption isotherms commendably. Moreover, the Cr loaded Fe/CMK-3 could be regenerated by 0.01 mol L-1 NaOH solution, and the removal capacity decreased by similar to 22% in the seventh cycle. X-ray photoelectron spectroscopy (XPS) analysis demonstrated that the Cr(VI) removal was a adsorption and synergistic reduction process owing to trivalent chromium Cr(III) occurring on the surface of Fe/CMK-3. The results suggested that Fe/CMK-3 had potential superiority in removal of Cr(VI) from wastewater. (C) 2013 Elsevier B.V. All rights reserved.