Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have... more Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have previously hindered direct comparisons of improvements in power production due to new cathode materials. However, one common reactor design has now been used in many different laboratories around the world under similar operating conditions based on using: a graphite fiber brush anode, a platinum cathode catalyst, a single-chamber cube-shaped (4-cm) MFC with a 3-cm diameter anolyte chamber, 50 mM phosphate buffer, and an acetate fuel. Analysis of several publications over 10 years from a single laboratory showed that even under such identical operational conditions, maximum power densities varied by 15%, with an average of 1.36 ± 0.20 W m-2 (n=24), normalized to cathode projected area (34 W m-3 liquid volume). In other laboratories, maximum power was significantly less, with an average of 0.91 ± 0.26 W m-2 (n=10), despite identical conditions. One likely reason for the differences in power is cathode age. Power production with Pt catalyst cathodes significantly declined after one month of operation or more to 0.87 ± 0.31 W
A hydrophobic Fe-N 4 /AC composite investigated as cathode catalyst for MFCs. � MFCs with 10 wt% ... more A hydrophobic Fe-N 4 /AC composite investigated as cathode catalyst for MFCs. � MFCs with 10 wt% Fe-N 4 /AC cathodes showed a 25% increase in power performance. � The hydrophobic Fe-N 4 /AC catalyst reduced water electrolyte evaporation. � Coulombic efficiency was simultaneously increased for the 10 wt% Fe-N 4 /AC cathodes.
Environmental Science: Water Research & Technology, 2018
Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activate... more Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activated carbon and stainless steel (SS) current collectors can result in decreased performance due to cathode fouling.
To scale up microbial fuel cells (MFCs), larger cathodes need to be developed that can use air di... more To scale up microbial fuel cells (MFCs), larger cathodes need to be developed that can use air directly, rather than dissolved oxygen, and have good electrochemical performance. A new type of cathode design was examined here that uses a "window-pane" approach with fifteen smaller cathodes welded to a single conductive metal sheet to maintain good electrical conductivity across the cathode with an increase in total area. Abiotic electrochemical tests were conducted to evaluate the impact of the cathode size (exposed areas of 7 cm, 33 cm, and 6200 cm) on performance for all cathodes having the same active catalyst material. Increasing the size of the exposed area of the electrodes to the electrolyte from 7 cm to 33 cm (a single cathode panel) decreased the cathode potential by 5%, and a further increase in size to 6200 cm using the multi-panel cathode reduced the electrode potential by 55% (at 0.6 A m), in a 50 mM phosphate buffer solution (PBS). In 85 L MFC tests with the l...
Metal-organic framework (MOF) on activated carbon (AC) enhanced the performance of cathodes but l... more Metal-organic framework (MOF) on activated carbon (AC) enhanced the performance of cathodes but longevity needs to be considered in the presence of metal chelators or ligands, such as phosphate, present in wastewaters. MOF catalysts on AC initially produced 2.78±0.08Wm(-2), but power decreased by 26% after eight weeks in microbial fuel cells using a 50mM phosphate buffer (PBS) and acetate due to decreased cathode performance. However, power was still 41% larger than that of the control AC (no MOF). Power generation using domestic wastewater was initially 0.73±0.01Wm(-2), and decreased by 21% over time, with power 53% larger than previous reports, although changes in wastewater composition were a factor in performance. Adding phosphate salts to the wastewater did not affect the catalyst performance over time. While MOF catalysts are therefore initially adversely affected by chelators, performance remains enhanced compared to plain AC.
Journal of Chemical Technology & Biotechnology, 2013
Non‐corrosive, carbon‐based materials are usually used as anodes in microbial fuel cells (MFCs). ... more Non‐corrosive, carbon‐based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m‐2). Higher power was produced with microbes using SS (12 mW m‐2) or carbon cloth (880 mW m‐2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. ...
Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have... more Differences in microbial fuel cell (MFC) architectures, materials, and solution chemistries, have previously hindered direct comparisons of improvements in power production due to new cathode materials. However, one common reactor design has now been used in many different laboratories around the world under similar operating conditions based on using: a graphite fiber brush anode, a platinum cathode catalyst, a single-chamber cube-shaped (4-cm) MFC with a 3-cm diameter anolyte chamber, 50 mM phosphate buffer, and an acetate fuel. Analysis of several publications over 10 years from a single laboratory showed that even under such identical operational conditions, maximum power densities varied by 15%, with an average of 1.36 ± 0.20 W m-2 (n=24), normalized to cathode projected area (34 W m-3 liquid volume). In other laboratories, maximum power was significantly less, with an average of 0.91 ± 0.26 W m-2 (n=10), despite identical conditions. One likely reason for the differences in power is cathode age. Power production with Pt catalyst cathodes significantly declined after one month of operation or more to 0.87 ± 0.31 W
A hydrophobic Fe-N 4 /AC composite investigated as cathode catalyst for MFCs. � MFCs with 10 wt% ... more A hydrophobic Fe-N 4 /AC composite investigated as cathode catalyst for MFCs. � MFCs with 10 wt% Fe-N 4 /AC cathodes showed a 25% increase in power performance. � The hydrophobic Fe-N 4 /AC catalyst reduced water electrolyte evaporation. � Coulombic efficiency was simultaneously increased for the 10 wt% Fe-N 4 /AC cathodes.
Environmental Science: Water Research & Technology, 2018
Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activate... more Long-term operation of wastewater-fed, microbial fuel cells (MFCs) with cathodes made of activated carbon and stainless steel (SS) current collectors can result in decreased performance due to cathode fouling.
To scale up microbial fuel cells (MFCs), larger cathodes need to be developed that can use air di... more To scale up microbial fuel cells (MFCs), larger cathodes need to be developed that can use air directly, rather than dissolved oxygen, and have good electrochemical performance. A new type of cathode design was examined here that uses a "window-pane" approach with fifteen smaller cathodes welded to a single conductive metal sheet to maintain good electrical conductivity across the cathode with an increase in total area. Abiotic electrochemical tests were conducted to evaluate the impact of the cathode size (exposed areas of 7 cm, 33 cm, and 6200 cm) on performance for all cathodes having the same active catalyst material. Increasing the size of the exposed area of the electrodes to the electrolyte from 7 cm to 33 cm (a single cathode panel) decreased the cathode potential by 5%, and a further increase in size to 6200 cm using the multi-panel cathode reduced the electrode potential by 55% (at 0.6 A m), in a 50 mM phosphate buffer solution (PBS). In 85 L MFC tests with the l...
Metal-organic framework (MOF) on activated carbon (AC) enhanced the performance of cathodes but l... more Metal-organic framework (MOF) on activated carbon (AC) enhanced the performance of cathodes but longevity needs to be considered in the presence of metal chelators or ligands, such as phosphate, present in wastewaters. MOF catalysts on AC initially produced 2.78±0.08Wm(-2), but power decreased by 26% after eight weeks in microbial fuel cells using a 50mM phosphate buffer (PBS) and acetate due to decreased cathode performance. However, power was still 41% larger than that of the control AC (no MOF). Power generation using domestic wastewater was initially 0.73±0.01Wm(-2), and decreased by 21% over time, with power 53% larger than previous reports, although changes in wastewater composition were a factor in performance. Adding phosphate salts to the wastewater did not affect the catalyst performance over time. While MOF catalysts are therefore initially adversely affected by chelators, performance remains enhanced compared to plain AC.
Journal of Chemical Technology & Biotechnology, 2013
Non‐corrosive, carbon‐based materials are usually used as anodes in microbial fuel cells (MFCs). ... more Non‐corrosive, carbon‐based materials are usually used as anodes in microbial fuel cells (MFCs). In some cases, however, metals have been used that can corrode (e.g. copper) or that are corrosion resistant (e.g. stainless steel, SS). Corrosion could increase current through galvanic (abiotic) current production or by increasing exposed surface area, or decrease current due to generation of toxic products from corrosion. In order to directly examine the effects of using corrodible metal anodes, MFCs with Cu were compared with reactors using SS and carbon cloth anodes. MFCs with Cu anodes initially showed high current generation similar to abiotic controls, but subsequently they produced little power (2 mW m‐2). Higher power was produced with microbes using SS (12 mW m‐2) or carbon cloth (880 mW m‐2) anodes, with no power generated by abiotic controls. These results demonstrate that copper is an unsuitable anode material, due to corrosion and likely copper toxicity to microorganisms. ...
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Papers by Bruce Logan