Natural Hematite as a Low-Cost and Earth-Abundant Cathode Material for Performance Improvement of Microbial Fuel Cells

Ren, Guiping; Ding, Haiyang; Li, Yan; Lu, Anhuai

doi:10.3390/catal6100157

Cited by 21 publications

(10 citation statements)

References 49 publications

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“…After the hematite electrode was used in the light-hematite-PAO1 system, no new peak was detected in the Raman spectrum, therefore during the experimental process no new mineral was formed suggesting great stability of the hematite electrode. Furthermore, the Fe concentration in the medium was determined by a modified Ferrozine method as previously reported [10]. However, no Fe 2+ was detected indicating the electrode was stable and not dissolving.…”

Section: Structure and Morphology Characterization Of The Hematite Elmentioning

confidence: 93%

“…Redox-active minerals, such as those that contain iron and manganese oxide minerals, are abundant in soils and in aquatic and subsurface sediments, which electrically support microbial growth in different kinds of ways [7]. Among a wide variety of Fe oxide minerals, hematite is the most widespread type on earth which has been demonstrated to work as the most common natural electron acceptor for the EET process by dissimilatory metal-reducing microorganisms [8][9][10][11]. However, one significant question has been overlooked in that hematite and some Fe/Mn oxides are semiconductive [12].…”

Section: Introductionmentioning

confidence: 99%

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Visible Light Enhanced Extracellular Electron Transfer between a Hematite Photoanode and Pseudomonas aeruginosa

Ren

Sun

et al. 2017

Minerals

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Exploring the interplay between sunlight, semiconducting minerals, and microorganisms in nature has attracted great attention in recent years. Here we report for the first time the investigation of the interaction between a hematite photoelectrode and Pseudomonas aeruginosa PAO1 under visible light irradiation. Hematite is the most abundant mineral on earth, with a band gap of 2.0 eV. A hematite electrode was electrochemically deposited on fluorine-doped tin oxide (FTO). It was thoroughly characterized by environmental scanning electron microscopy (ESEM), Raman, and UV-Vis spectroscopy, and its prompt response to visible light was determined by linear sweep voltammetry (LSV). Notably, under light illumination, the hematite electrode immersed in a live cell culture was able to produce 240% more photocurrent density than that in the abiotic control of the medium, suggesting a photoenhanced extracellular electron transfer process occurring between hematite and PAO1. Different temperatures of LSV measurements showed bioelectrochemical activity in the system. Furthermore, It curves under various conditions demonstrated that both a direct and an indirect electron transferring process occurred between the hematite photoanode and PAO1. Moreover, the indirect electron transferring route was more dominant, which may be mainly attributed to the pyocyanin biosynthesized by PAO1. Our results have expanded our understanding in that in addition to Geobacter and Shewanella it has been shown that more microorganisms are able to perform enhanced extracellular electron transfer with semiconducting minerals under sunlight in nature.

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Section: Structure and Morphology Characterization Of The Hematite Elmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Visible Light Enhanced Extracellular Electron Transfer between a Hematite Photoanode and Pseudomonas aeruginosa

Ren

Sun

et al. 2017

Minerals

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“…For example, the maximum power of 64.7 mW·m −2 for Co-naphthalocyanine, 81.3 mW·m −2 for Pt/C electrode, 29.7 mW·m −2 for NPc/C, and 9.3 mW·m −2 for carbon black in H-type MFCs [33]. Moreover, the value of pyrrhotite-coated cathode had similar values with hematite or manganese oxides (30-180 mW·m −2 ), carbon felt (77 mW·m −2 ) or PbO 2 (<80 mW· m −2 ) [21][22][23][24][25]. In addition, compared with the graphite cathode, the MFCs with cathodes modified by pyrrhotite generated the higher open circuit voltage for 528 mV and achieved a significantly lower system resistance than control group (Table 1).…”

Section: The Electricity Production Performance Of Mfcsmentioning

confidence: 51%

Enhanced Performance for Treatment of Cr (VI)-Containing Wastewater by Microbial Fuel Cells with Natural Pyrrhotite-Coated Cathode

Shi

Zhao

Liu

et al. 2017

Water

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Abstract:Here we reported the investigation of enhanced performance for the removal of hexavalent chromium (Cr (VI)) by a new microbial fuel cell (MFC) with natural pyrrhotite-coated cathode. By comparisons of the graphite-cathode, the MFCs equipped with a pyrrhotite-coated cathode generated the maximum power density of 45.4 mW·m −2 that was 1.3 times higher than that of with bare graphite cathode (35.5 mW·m −2 ). Moreover, the Cr (VI) removal efficiency of 97.5% achieved after 4.5 h compared with only 46.1% by graphite cathode MFC. In addition, Cr (VI) removal rate with different initial Cr (VI) concentrations for 10 mg/L and 30 mg/L was investigated and a decreased removal percentage with increasing Cr (VI) concentration was observed. Batches of experiments of different pH values from 3.0 to 9.0 in catholyte were carried out to optimize system performance. The complete Cr (VI) removal was achieved at pH 3.0 and 99.59% of Cr (VI) was removed after 10.5 h, which met the requirement of the Cr (VI) National Emission Standard. When the value of pH was decreasing, the removal rate was obviously increased and Cr (VI) could be removed successfully with a broad pH range indicating pyrrhotite-coated cathode MFC had more extensive usage scope. Furthermore, cathode treatment products were studied by X-ray photoelectron spectroscopy (XPS), Cr 2 O 3 , Cr (III)-acetate were detected on the cathode by the XPS Cr2p spectra and no Cr (VI) founded, indicating that the Cr on the surface of cathode was Cr (III) and Cr (VI) were reduced. On cathode, pyrrhotite not only played a significant role for catalyst of MFCs, but also acted as reactive sites for Cr (VI) reduction. Our research demonstrated that pyrrhotite, an earth-abundant and low-cost natural mineral was promised as an effective cathode material. Which had great potential applications in MFCs for reduction of wastewater containing heavy metals and other environmental contaminants in the future.

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“…Firstly, 400 mg of wolframite was mixed with ethanol solution (4 mL) and 5% Nafion solution (10 µL). Secondly, the mixture was ultrasonically dispersed for 10 min and then dropped onto the graphite surfaces, which were already polished by abrasive paper and cleaned by soaking in HCl/NaOH as described in a previous study [19]. After air-drying, the wolframite-coated cathode was completed.…”

Section: Preperation Of Wolframite-coated Cathode and Mfcs Start-upmentioning

confidence: 99%

“…After using these simple metal oxides, the performance of MFCs was increased, but these materials still waste some chemical reagents during their synthesis processes. It is worthwhile mentioning that Ren et al first investigated the utilization of natural hematite as a cathode catalyst in a traditional MFC, which indicated that the maximum power density in a hematite-coated cathode MFC was 2.2 times higher than that in a graphite cathode MFC, and a current density of 330.66 mA•m −2 was stabilized over 10 days [19]. Shi et al studied the performance and Cr(VI) removal efficiencies by natural pyrrhotite-coated cathode MFCs and demonstrated that the natural pyrrhotite not only played the role of catalyst, but also acted as a reactive site for Cr(VI) reduction [20].…”

Section: Introductionmentioning

confidence: 99%

Natural Wolframite Used as Cathode Photocatalyst for Improving the Performance of Microbial Fuel Cells

Shi

Chu

et al. 2018

Applied Sciences

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Developing simple and cheap electrocatalysts or photocatalysts for cathodes to increase the oxygen reduction process is a key factor for better utilization of microbial fuel cells (MFCs). Here, we report the investigation of natural wolframite employed as a low-cost cathode photocatalyst to improve the performance of MFCs. The semiconducting wolframite was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. The band gap and photo respond activities were determined by UV-vis spectroscopy and linear sweep voltammetry (LSV), respectively. Compared with the normal graphite cathode, when MFCs were equipped with a wolframite-coated cathode, the maximum power density was increased from 41.47 mW·m−2 to 95.51 mW·m−2. Notably, the maximum power density further improved to 135.57 mW·m−2 under light irradiation, which was 2.4 times higher than with a graphite cathode. Our research demonstrated that natural wolframite, a low-cost and abundant natural semiconducting mineral, showed promise as an effective photocathode catalyst which has great potential applications related to utilizing natural minerals in MFCs and for environmental remediation by MFCs in the future.

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Natural Hematite as a Low-Cost and Earth-Abundant Cathode Material for Performance Improvement of Microbial Fuel Cells

Cited by 21 publications

References 49 publications

Visible Light Enhanced Extracellular Electron Transfer between a Hematite Photoanode and Pseudomonas aeruginosa

Visible Light Enhanced Extracellular Electron Transfer between a Hematite Photoanode and Pseudomonas aeruginosa

Enhanced Performance for Treatment of Cr (VI)-Containing Wastewater by Microbial Fuel Cells with Natural Pyrrhotite-Coated Cathode

Natural Wolframite Used as Cathode Photocatalyst for Improving the Performance of Microbial Fuel Cells

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