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Impact of Fe(III) as an effective electron-shuttle mediator for enhanced Cr(VI) reduction in microbial fuel cells: Reduction of diffusional resistances and cathode overpotentials

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journal contribution
posted on 14.12.2016 by Qiang Wang, Liping Huang, Yuzhen Pan, Xie Quan, Gianluca Li-Puma
© 2016 Elsevier B.V.The role of Fe(III) was investigated as an electron-shuttle mediator to enhance the reduction rate of the toxic heavy metal hexavalent chromium (Cr(VI)) in wastewaters, using microbial fuel cells (MFCs). The direct reduction of chromate (CrO4−) and dichromate (Cr2O72−) anions in MFCs was hampered by the electrical repulsion between the negatively charged cathode and Cr(VI) functional groups. In contrast, in the presence of Fe(III), the conversion of Cr(VI) and the cathodic coulombic efficiency in the MFCs were 65.6% and 81.7%, respectively, 1.6 times and 1.4 folds as those recorded in the absence of Fe(III). Multiple analytical approaches, including linear sweep voltammetry, Tafel plot, cyclic voltammetry, electrochemical impedance spectroscopy and kinetic calculations demonstrated that the complete reduction of Cr(VI) occurred through an indirect mechanism mediated by Fe(III). The direct reduction of Cr(VI) with cathode electrons in the presence of Fe(III) was insignificant. Fe(III) played a critical role in decreasing both the diffusional resistance of Cr(VI) species and the overpotential for Cr(VI) reduction. This study demonstrated that the reduction of Cr(VI) in MFCs was effective in the presence of Fe(III), providing an alternative and environmentally benign approach for efficient remediation of Cr(VI) contaminated sites with simultaneous production of renewable energy.

Funding

This work was supported by the National Natural Science Foundation of China (Nos. 21377019 and 51578104), Specialized Research Fund for the Doctoral Program of Higher Education “SRFDP” (No. 20120041110026), and the Program for Changjiang Scholars and Innovative Research Team in University (IRT_13R05)

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Journal of Hazardous Materials

Volume

321

Pages

896 - 906

Citation

WANG, Q. ...et al., 2016. Impact of Fe(III) as an effective electron-shuttle mediator for enhanced Cr(VI) reduction in microbial fuel cells: Reduction of diffusional resistances and cathode overpotentials. Journal of Hazardous Materials, 321, pp. 896-906.

Publisher

© Elsevier

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Acceptance date

05/10/2016

Publication date

2016

Notes

This paper was accepted for publication in the journal Journal of Hazardous Materials and the definitive published version is available at https://doi.org/10.1016/j.jhazmat.2016.10.011

ISSN

0304-3894

eISSN

1873-3336

Language

en

Exports