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. 2023 Nov 17;13(1):20184.
doi: 10.1038/s41598-023-47450-9.

Insights on hexavalent chromium(VI) remediation strategies in abiotic and biotic dual chamber microbial fuel cells: electrochemical, physical, and metagenomics characterizations

Dena Z Khater  1 , R S Amin  1 , Amani E Fetohi  1 , Mohamed Mahmoud  2   3 , K M El-Khatib  4
Affiliations

Insights on hexavalent chromium(VI) remediation strategies in abiotic and biotic dual chamber microbial fuel cells: electrochemical, physical, and metagenomics characterizations

Dena Z Khater et al. Sci Rep. .

Abstract

Hexavalent chromium [Cr(VI)] is one of the most carcinogenic and mutagenic toxins, and is commonly released into the environemt from different industries, including leather tanning, pulp and paper manufacturing, and metal finishing. This study aimed to investigate the performance of dual chamber microbial fuel cells (DMFCs) equipped with a biocathode as alternative promising remediation approaches for the biological reduction of hexavalent chromium [Cr(VI)] with instantaneous power generation. A succession batch under preliminary diverse concentrations of Cr(VI) (from 5 to 60 mg L-1) was conducted to investigate the reduction mechanism of DMFCs. Compared to abiotic-cathode DMFC, biotic-cathode DMFC exhibited a much higher power density, Cr(VI) reduction, and coulombic efficiency over a wide range of Cr(VI) concentrations (i.e., 5-60 mg L-1). Furthermore, the X-ray photoelectron spectroscopy (XPS) revealed that the chemical functional groups on the surface of biotic cathode DMFC were mainly trivalent chromium (Cr(III)). Additionally, high throughput sequencing showed that the predominant anodic bacterial phyla were Firmicutes, Proteobacteria, and Deinococcota with the dominance of Clostridiumsensu strict 1, Enterobacter, Pseudomonas, Clostridiumsensu strict 11 and Lysinibacillus in the cathodic microbial community. Collectively, our results showed that the Cr(VI) removal occurred through two different mechanisms: biosorption and bioelectrochemical reduction. These findings confirmed that the DMFC could be used as a bioremediation approach for the removal of Cr(VI) commonly found in different industrial wastewater, such as tannery effluents. with simultaneous bioenergy production.

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Conflict of interest statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

Figure 1
Figure 1
Open circuit potential of MFC bioreactors.
Figure 2
Figure 2
The effect of initial Cr6+ concentration (from 5 to 60 mg L−1) on the (a) closed-ciruit potential generation and (b) power density output. Error bars indicate the relative standard deviation of two replicates.
Figure 3
Figure 3
(a) Coulombic efficiency (CE) and removal efficiencies (RE), (b) adaptation of microbial community over time and different Cr(VI) concentrations, and (c) power and polarization curves for abiotic and biotic cathode DMFC reactors during the experimental period at 10 KΩ resistance.
Figure 4
Figure 4
XPS spectra of (a) XPS survey spectrum of biotic cathode and high-resolution XPS spectra of (b) C 1s, (c) O 1s, and (d) Cr2p. (e) XPS survey spectrum of abiotic cathode and high-resolution XPS spectra of (f) C 1s and (g) O 1s.
Figure 5
Figure 5
Microbial diversity analysis related to Cr(VI) cytotoxicity: (a) the functional analysis of expressed genes using PICRust, (b) relative abundance of bacterial community sequencing results at the phylum level (Phylotypes < 1% of total sequences were classified as “others”), (c) Heat map depicting the comparison of the relative abundance of the dominant microbial genera, and (d) Phylogenetic tree at genus level of biocathodic and anodic biofilms in biotic MFC.
Figure 5
Figure 5
Microbial diversity analysis related to Cr(VI) cytotoxicity: (a) the functional analysis of expressed genes using PICRust, (b) relative abundance of bacterial community sequencing results at the phylum level (Phylotypes < 1% of total sequences were classified as “others”), (c) Heat map depicting the comparison of the relative abundance of the dominant microbial genera, and (d) Phylogenetic tree at genus level of biocathodic and anodic biofilms in biotic MFC.
Figure 6
Figure 6
SEM analysis and EDX spectra coupled with elemental mapping of (a) abiotic and (b) biotic cathode DMFCs.
Figure 7
Figure 7
Proposed mechanism for Cr(VI) reduction in MFCs.
See this image and copyright information in PMC

References

    1. Li M, Zhou S, Xu Y, Liu Z, Ma F, Zhi L, Zhou X. Simultaneous Cr(VI) reduction and bioelectricity generation in a dual chamber microbial fuel cell. Chem. Eng. J. 2018;334:1621–1629. doi: 10.1016/j.cej.2017.11.144. - DOI
    1. Thacher R, Hsu L, Ravindran V, Nealson KH. Modeling the transport and bioreduction of hexavalent chromium in aquifers: Influence of natural organic matter. Chem. Eng. Sci. 2015;138:552–565. doi: 10.1016/j.ces.2015.08.011. - DOI
    1. Yan J, et al. Enhanced reduction of sulfate and chromium under sulfate-reducing condition by synergism between extracellular polymeric substances and graphene oxide. Environ. Res. 2020;183:109157. doi: 10.1016/j.envres.2020.109157. - DOI - PubMed
    1. World Health Organization. Guidelines for drinking-water quality incorporating first addendum: Recommendations. (2006). - PubMed
    1. Vendruscolo F, da Rocha Ferreira GL, Antoniosi Filho NR. Biosorption of hexavalent chromium by microorganisms. Int. Biodeterior. Biodegrad. 2017;119:87–95. doi: 10.1016/j.ibiod.2016.10.008. - DOI