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Title: 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
Authors: Wang, Qiang
Huang, Liping
Pan, Yuzhen
Quan, Xie
Li Puma, Gianluca
Keywords: Cr(VI) reduction
Fe(III) mediator
Diffusion resistance
Cathode overpotential
Microbial fuel cell
Issue Date: 2016
Publisher: © Elsevier
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.
Abstract: © 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.
Description: 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
Sponsor: 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)
Version: Accepted for publication
DOI: 10.1016/j.jhazmat.2016.10.011
URI: https://dspace.lboro.ac.uk/2134/23435
Publisher Link: http://dx.doi.org/10.1016/j.jhazmat.2016.10.011
ISSN: 0304-3894
Appears in Collections:Published Articles (Chemical Engineering)

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