Performance Assessment of Multi-Electrodes Reactors for Scaling-up Microbial Fuel Cells

The microbial fuel cells (MFCs) represent an emerging technology for converting directly organic waste into electricity. In recent years, the application of MFCs to the energy recovery from wastes has been widely explored. The main aspect that limits the development and implementation of this technology on a larger-scale is the possibility of realizing its scaling-up. In order to overcome this critical factor, it is useful to analyze novel MFCs configurations based on compact reactors with multiple electrodes.In this paper, single chamber MFCs provided with multiple fiber brush anodes and a single air-cathode were designed and realized by using a 3D printer. The reactors had a cubic shape, with a cylindrical chamber of 350 mL in volume. The mineral medium added with sodium acetate (0.25 M), as sole source of carbon and energy to sustain exoelectrogenic bacteria metabolism, were used. Anodes biofilms were prepared from a mix of compost and sodium acetate dissolved in phosphate buffer solution (0.2M), in a 1:3 ratio. The performances of two MFCs provided with two and three anodes were assessed in terms of voltage, current density and power density. These performances were compared to those of a smaller cubic MFC (30mL).

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Investigating Air-Cathode Microbial Fuel Cells Performance under Different Serially and Parallelly Connected Configurations

Energies ◽

10.3390/en14165116 ◽

2021 ◽

Vol 14 (16) ◽

pp. 5116

Author(s):

Mariagiovanna Minutillo ◽

Simona Di Micco ◽

Paolo Di Giorgio ◽

Giovanni Erme ◽

Elio Jannelli

Keyword(s):

Fuel Cells ◽

Energy Density ◽

Power Density ◽

Microbial Fuel Cells ◽

Scaling Up ◽

Point Of View ◽

Air Cathode ◽

In Series ◽

Valid Solution ◽

Parallel Series

Microbial fuel cells (MFCs) have recently attracted more attention in the context of sustainable energy production. They can be considered as a future solution for the treatment of organic wastes and the production of bioelectricity. However, the low output voltage and the low produced electricity limit their applications as energy supply systems. The scaling up of MFCs both by developing bigger reactors with multiple electrodes and by connecting several cells in stacked configurations is a valid solution for improving these performances. In this paper, the scaling up of a single air-cathode microbial fuel cell with an internal volume of 28 mL, has been studied to estimate how its performance can be improved (1523 mW/m3, at 0.139 mA). Four stacked configurations and a multi-electrode unit have been designed, developed, and tested. The stacked MFCs consist of 4 reactors (28 mL × 4) that are connected in series, parallel, series/parallel, and parallel/series modes. The multi-electrode unit consists of a bigger reactor (253 mL) with 4 anodes and 4 cathodes. The performance analysis has point ed out that the multi-electrode configuration shows the lowest performances in terms of volumetric power density equal to 471 mW/m3 at 0.345 mA and volumetric energy density of 624.2 Wh/m3. The stacked parallel/series configuration assures both the highest volumetric power density, equal to 2451 mW/m3 (274.6 µW) at 0.524 mA and the highest volumetric energy density, equal to 2742.0 Wh/m3. These results allow affirming that to increase the electric power output of MFCs, the stacked configuration is the optimal strategy from designing point of view.

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Use of Biochar-Based Cathodes and Increase in the Electron Flow by Pseudomonas aeruginosa to Improve Waste Treatment in Microbial Fuel Cells

Processes ◽

10.3390/pr9111941 ◽

2021 ◽

Vol 9 (11) ◽

pp. 1941

Author(s):

Rosa Anna Nastro ◽

Fabio Flagiello ◽

Nicandro Silvestri ◽

Edvige Gambino ◽

Giacomo Falcucci ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Fuel Cells ◽

Microbial Fuel Cells ◽

Cathode Surface ◽

Waste Treatment ◽

Electron Flow ◽

Phosphate Buffer Solution ◽

Current Collector ◽

Composite Cathode ◽

Buffer Solution

In this paper, we tested the combined use of a biochar-based material at the cathode and of Pseudomonas aeruginosa strain in a single chamber, air cathode microbial fuel cells (MFCs) fed with a mix of shredded vegetable and phosphate buffer solution (PBS) in a 30% solid/liquid ratio. As a control system, we set up and tested MFCs provided with a composite cathode made up of a nickel mesh current collector, activated carbon and a single porous poly tetra fluoro ethylene (PTFE) diffusion layer. At the end of the experiments, we compared the performance of the two systems, in the presence and absence of P. aeruginosa, in terms of electric outputs. We also explored the potential reutilization of cathodes. Unlike composite material, biochar showed a life span of up to 3 cycles of 15 days each, with a pH of the feedstock kept in a range of neutrality. In order to relate the electric performance to the amount of solid substrates used as source of carbon and energy, besides of cathode surface, we referred power density (PD) and current density (CD) to kg of biomass used. The maximum outputs obtained when using the sole microflora were, on average, respectively 0.19 Wm−2kg−1 and 2.67 Wm−2kg−1, with peaks of 0.32 Wm−2kg−1 and 4.87 Wm−2kg−1 of cathode surface and mass of treated biomass in MFCs with biochar and PTFE cathodes respectively. As to current outputs, the maximum values were 7.5 Am−2 kg−1 and 35.6 Am−2kg−1 in MFCs with biochar-based material and a composite cathode. If compared to the utilization of the sole acidogenic/acetogenic microflora in vegetable residues, we observed an increment of the power outputs of about 16.5 folds in both systems when we added P. aeruginosa to the shredded vegetables. Even though the MFCs with PTFE-cathode achieved the highest performance in terms of PD and CD, they underwent a fouling episode after about 10 days of operation, with a dramatic decrease in pH and both PD and CD. Our results confirm the potentialities of the utilization of biochar-based materials in waste treatment and bioenergy production.

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Increasing power generation for scaling up single-chamber air cathode microbial fuel cells

Bioresource Technology ◽

10.1016/j.biortech.2010.12.104 ◽

2011 ◽

Vol 102 (6) ◽

pp. 4468-4473 ◽

Cited By ~ 197

Author(s):

Shaoan Cheng ◽

Bruce E. Logan

Keyword(s):

Power Generation ◽

Fuel Cells ◽

Microbial Fuel Cells ◽

Scaling Up ◽

Air Cathode ◽

Single Chamber

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Polyelectrolyte–single wall carbon nanotube composite as an effective cathode catalyst for air-cathode microbial fuel cells

Water Science & Technology ◽

10.2166/wst.2014.416 ◽

2014 ◽

Vol 70 (10) ◽

pp. 1610-1616 ◽

Cited By ~ 2

Author(s):

Huanan Wu ◽

Min Lu ◽

Lin Guo ◽

Leonard Guan Hong Bay ◽

Zheng Zhang ◽

...

Keyword(s):

Fuel Cells ◽

Carbon Nanotube ◽

Oxygen Reduction ◽

Microbial Fuel Cells ◽

Reduction Process ◽

Air Cathode ◽

Single Wall Carbon Nanotube ◽

Single Wall Carbon ◽

Cathode Catalysts ◽

Metal Free

Polyelectrolyte–single wall carbon nanotube (SCNT) composites are prepared by a solution-based method and used as metal-free cathode catalysts for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). In this study, two types of polyelectrolytes, polydiallyldimethylammonium chloride (PDDA) and poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (PEPU) are applied to decorate the SCNTs and the resulting catalysts exhibit remarkable catalytic ability toward ORR in MFC applications. The enhanced catalytic ability could be attributed to the positively charged quaternary ammonium sites of polyelectrolytes, which increase the oxygen affinity of SCNTs and reduce activation energy in the oxygen reduction process. It is also found that PEPU–SCNT composite-based MFCs show efficient performance with maximum power density of 270.1 mW m−2, comparable to MFCs with the benchmark Pt/C catalyst (375.3 mW m−2), while PDDA–SCNT composite-based MFCs produce 188.9 mW m−2. These results indicate that PEPU–SCNT and PDDA–SCNT catalysts are promising candidates as metal-free cathode catalysts for ORR in MFCs and could facilitate MFC scaling up and commercialization.

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