Anodic concentration loss and impedance characteristics in rotating disk electrode microbial fuel cells

Shen, Liye; Ma, Jingxing; Song, Pengfei; Lu, Zhihao; Yin, Yao; Liu, Yongdi; Cai, Lankun; Zhang, Lehua

doi:10.1007/s00449-016-1638-1

Cited by 12 publications

(7 citation statements)

References 43 publications

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“…Though bioelectrochemical systems employ flow to improve nutrient delivery and metabolic waste removal 6–9 , which is known to influence biofilm behavior, the independent influence of shear on electrochemically active biofilms remains largely unexplored 6–11 . Short-term exposures of electroactive biofilms to shear showed expected improvements in salt transport 12 and unexpected resilience to high shear (635 s −1 ) 13 despite forming thicker biofilms than aerobic bacteria 5 . Long-term exposures to shear showed that high shear (200 s −1 ) selects for high-current producing bacteria compared to low shear (80 s −1 ) 14 .…”

Section: Introductionmentioning

confidence: 99%

Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport

Jones

Buie

2019

Sci Rep

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Electroactive bacteria such as Geobacter sulfurreducens and Shewanella onedensis produce electrical current during their respiration; this has been exploited in bioelectrochemical systems. These bacteria form thicker biofilms and stay more active than soluble-respiring bacteria biofilms because their electron acceptor is always accessible. In bioelectrochemical systems such as microbial fuel cells, corrosion-resistant metals uptake current from the bacteria, producing power. While beneficial for engineering applications, collecting current using corrosion resistant metals induces pH stress in the biofilm, unlike the naturally occurring process where a reduced metal combines with protons released during respiration. To reduce pH stress, some bioelectrochemical systems use forced convection to enhance mass transport of both nutrients and byproducts; however, biofilms’ small pore size limits convective transport, thus, reducing pH stress in these systems remains a challenge. Understanding how convection is necessary but not sufficient for maintaining biofilm health requires decoupling mass transport from momentum transport (i.e. fluidic shear stress). In this study we use a rotating disc electrode to emulate a practical bioelectrochemical system, while decoupling mass transport from shear stress. This is the first study to isolate the metabolic and structural changes in electroactive biofilms due to shear stress. We find that increased shear stress reduces biofilm development time while increasing its metabolic rate. Furthermore, we find biofilm health is negatively affected by higher metabolic rates over long-term growth due to the biofilm’s memory of the fluid flow conditions during the initial biofilm development phases. These results not only provide guidelines for improving performance of bioelectrochemical systems, but also reveal features of biofilm behavior. Results of this study suggest that optimized reactors may initiate operation at high shear to decrease development time before decreasing shear for steady-state operation. Furthermore, this biofilm memory discovered will help explain the presence of channels within biofilms observed in other studies.

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Section: Introductionmentioning

confidence: 99%

Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport

Jones

Buie

2019

Sci Rep

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“…Rotating disk electrodes can provide a well‐defined flow regime for the study of electrochemical and bioelectrochemical processes under defined convective conditions (Table , upper section) . For this reason, they are applied to investigate the influence of a culture medium flow on EAB growth and performance . These studies reported current density increases in the range of 10 % to 22 % as well as an improvement in startup time and early current density due to the applied medium flow .…”

Section: Resultsmentioning

confidence: 99%

“…For this reason, they are applied to investigate the influence of a culture medium flow on EAB growth and performance . These studies reported current density increases in the range of 10 % to 22 % as well as an improvement in startup time and early current density due to the applied medium flow . The increase of current density has generally been attributed to an enhanced mass transfer through the electroactive biofilm which has been observed by electrochemical impedance spectroscopy as a decrease in concentration resistance .…”

Section: Resultsmentioning

confidence: 99%

“…These studies reported current density increases in the range of 10 % to 22 % as well as an improvement in startup time and early current density due to the applied medium flow . The increase of current density has generally been attributed to an enhanced mass transfer through the electroactive biofilm which has been observed by electrochemical impedance spectroscopy as a decrease in concentration resistance . It has also been observed that the influence of the culture medium flow on EAB performance will to a large degree depend on the growth conditions: In systems with significant mass transfer limitations, which could be the case for very low electron donor or buffer concentrations, a stronger effect was observed …”

Section: Resultsmentioning

confidence: 99%

“…On a microscopic scale, the flow of the culture medium can facilitate mass transfer through the biofilm and it is thus expected to affect EAB performance to some degree . An increase in performance of EAB has been reported in several studies when the biofilms were subjected to defined shear stresses . Additionally, shear forces can influence biofilm thickness and morphology by inducing the detachment of biomass from the biofilm surface and the production of extracellular polymeric substances favoring the formation of thinner and more concentrated biofilm structures .…”

Section: Introductionmentioning

confidence: 99%

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Studying the Impact of Wall Shear Stress on the Development and Performance of Electrochemically Active Biofilms

et al. 2020

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A laminar flow reactor was designed that provides constant and reproducible growth conditions for the bioelectrochemical observation of electroactive bacteria (EAB). Experiments were performed using four reactors in parallel to enable the comparison of EAB growth behavior and bioelectrochemical performance under different hydrodynamic conditions while simultaneously keeping biological conditions identical. With regard to the moderate flow conditions found in wastewater treatment applications, the wall shear stress was adjusted to a range between 0.4 mPa to 2.9 mPa. Chronoamperometric data indicate that early stage current densities are improved by a moderate increase of the wall shear stress. In the same way, current onset times were increasing slightly towards higher values of the applied wall shear stress. Long‐term observations of EAB performance showed a decrease in current density and a leveling of the trend observed for the early stages of biofilm growth.

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Effect of organic loading on bioelectricity generation potential of dual‐chambered microbial fuel cell treating chocolaterie wastewater

Xu¹,

ArunKumar

Jeyakumar

2023

Env Prog and Sustain Energy

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Microbial fuel cells (MFC) are recent advancements in treating wastewater and generating power simultaneously. In the present study, chocolaterie wastewater rich in organic content was the substrate in a dual‐chambered MFC. Activated Carbon Fiber Felt (ACFF) electrodes (anode and cathode) were separated by Nafion 117 proton exchange membrane in the dual‐chambered reactor. The primary goal was to investigate the impact of organic loading on MFC efficiency in treating chocolaterie wastewater and carrying out microbial analysis. 1, 2, 3, and 4 gCOD/L were the organic loadings of the reactor. MFC performance increased till the optimum value, and after that, it declined. A total of 2 gCOD/L was the optimum organic loading. At this optimum organic loading, dual‐chambered MFC removed 79% of total chemical oxygen demand (TCOD), 70% of soluble chemical oxygen demand (SCOD), and 67% of total suspended solids (TSS). At 2 gCOD/L organic loading, the maximum power density was 99 mW/m2. Coulombic efficiency was 58% at 1 gCOD/L and 30% at 2 gCOD/L organic loadings. Microbial analysis revealed the presence of Ochrobactrum and Pseudomonas sp. as dominant exoelectrogens in the anodic biofilm. These species were proven for the contaminant degradation efficiency and potential for power generation. Hence dual‐chambered MFCs can treat high‐strength chocolaterie wastewaters efficiently at optimum operating conditions.

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Anodic concentration loss and impedance characteristics in rotating disk electrode microbial fuel cells

Cited by 12 publications

References 43 publications

Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport

Continuous shear stress alters metabolism, mass-transport, and growth in electroactive biofilms independent of surface substrate transport

Studying the Impact of Wall Shear Stress on the Development and Performance of Electrochemically Active Biofilms

Effect of organic loading on bioelectricity generation potential of dual‐chambered microbial fuel cell treating chocolaterie wastewater

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