Enhancement of the Start-Up Time for Microliter-Scale Microbial Fuel Cells (µMFCs) via the Surface Modification of Gold Electrodes (original) (raw)
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Influence of anode surface chemistry on microbial fuel cell operation
Bioelectrochemistry (Amsterdam, Netherlands), 2015
Self-assembled monolayers (SAMs) modified gold anodes are used in single chamber microbial fuel cells for organic removal and electricity generation. Hydrophilic (N(CH3)3(+), OH, COOH) and hydrophobic (CH3) SAMs are examined for their effect on bacterial attachment, current and power output. The different substratum chemistry affects the community composition of the electrochemically active biofilm formed and thus the current and power output. Of the four SAM-modified anodes tested, N(CH3)3(+) results in the shortest start up time (15days), highest current achieved (225μAcm(-2)) and highest MFC power density (40μWcm(-2)), followed by COOH (150μAcm(-2) and 37μWcm(-2)) and OH (83μAcm(-2) and 27μWcm(-2)) SAMs. Hydrophobic SAM decreases electrochemically active bacteria attachment and anode performance in comparison to hydrophilic SAMs (CH3 modified anodes 7μAcm(-2) anodic current and 1.2μWcm(-2) MFC's power density). A consortium of Clostridia and δ-Proteobacteria is found on all t...
Influence of Anodes Surface Chemistry on Microbial Fuel Cells Operation
Bioelectrochemistry, 2015
Self-assembled monolayers (SAMs) modified gold anodes are used in single chamber microbial fuel cells for organic removal and electricity generation. Hydrophilic (\ \N(CH 3 ) 3 + , \ \OH, \ \COOH) and hydrophobic (\ \CH 3 ) SAMs are examined for their effect on bacterial attachment, current and power output. The different substratum chemistry affects the community composition of the electrochemically active biofilm formed and thus the current and power output. Of the four SAM-modified anodes tested, \ \N(CH 3 ) 3 + results in the shortest start up time (15 days), highest current achieved (225 μA cm −2 ) and highest MFC power density (40 μW cm −2 ), followed by\ \COOH (150 μA cm −2 and 37 μW cm −2 ) and\ \OH (83 μA cm −2 and 27 μW cm −2 ) SAMs. Hydrophobic SAM decreases electrochemically active bacteria attachment and anode performance in comparison to hydrophilic SAMs (\ \CH 3 modified anodes 7 μA cm −2 anodic current and 1.2 μW cm −2 MFC's power density). A consortium of Clostridia and δ-Proteobacteria is found on all the anode surfaces, suggesting a synergistic cooperation under anodic conditions.
Micro-/Nano-Structured Anodes for Enhanced Performance of Micro-Sized Microbial Fuel Cells
2014 Solid-State, Actuators, and Microsystems Workshop Technical Digest, 2014
Microbial fuel cells (MFCs) are gaining acceptance as a future alternative green energy technology and energy-efficient wastewater treatment method. Despite their vast potential, however, our ability to harness the potential of MFC technology lags from its low power density limiting its practical applications. Among a number of factors that can affect the MFC's performance, the anode material has the greatest impact on the performance by determining the actual accessible surface area for bacteria to attach and affecting the interfacial electron transfer resistance. In this work, microbial electricity generations on six micro/nanostructured anodes in micro-sized MFCs (57 μL) have been investigated by probing the behavior and physiology of microbial biofilm and their interaction with each anode at a new level of detail and efficiency. Six anodes are carbon nanotube (CNT), carbon nanofiber (CNF), gold/PCL microfiber (GPM), gold/PCL nanofiber (GPN), planar gold (PG), and conventional carbon paper (CP).
Electrochemical impedance spectroscopy a b s t r a c t Various materials and anode structures have been applied to enhance MFC performance. However, their comparative evaluation of performance and electrochemistry has not yet been investigated in detail under a same condition. In this study, a carbon-cloth anode, an anode-cathode assembly, and a brush anode with two different orientations were tested under a same condition for comparative analyses on their performance and electro-chemistry, in order to reveal their unique electrochemical characteristics. The brush anode cells exhibited better performance than the carbon cloth cells. The brush anodes showed 41e72% higher maximum power densities, 18e75% higher maximum current density and 24e32% higher optimum current densities than the carbon cloth anodes. The brush anodes showed 25e43 U lower anodic polarization resistance than the carbon cloth anodes. The brush anodes showed 1.6e21.2 U lower ohmic impedance, 7.7e10.6 U lower charge transfer impedance and 9.3e31.8 U lower anodic impedance than the carbon cloth anodes. Anodic ohmic impedance was greatest in the carbon-cloth-anode MFC (21.9 U), where loose contact between a carbon cloth and a current collector might cause the high ohmic resistance, and large solution resistance in the cell could diminish anode performance due to slow ion transport. In order to improve MFC performance by modifying anode structures, we suggest the followings: 1) an anode should have large surface area, 2) anodic carbon material and a metal current collector must be tightly connected, 3) locating a brush anode closer to a cathode can be important. ScienceDirect j o urn al h om epa ge: www.elsev ier.com/locate/he i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y 4 2 (2 0 1 7) 2 7 6 7 7 e2 7 6 8 4
ACS Applied Bio Materials, 2020
The present study reports about the fabrication of a threedimensional (3D) macroporous steel-based scaffold as an anode to promote specifically bacterial attachment and extracellular electron transfer to achieve power density as high as 1184 mW m −2 , which is far greater than that of commonly used 3D anode materials. The unique 3D open macroporous configuration of the anode and the microstructure generated by the composite coating provide voids for the 3D bacterial colonization of electroactive biofilms. This is attributed to the sizeable interfacial area per unit volume provided by the 3D corrugated electrode that enhanced the electrochemical reaction rate compared to that of the flat electrode, which favors the enhanced mass transfer and substrate diffusion at the electrode/electrolyte interface and thereby increases the charge transfer by reducing the electrode overpotential or interfacial resistance. In addition, bacterial infiltration into the interior of the anode renders large reaction sites for substrate oxidation without the concern of clogging and biofouling and thereby improves direct electron transfer. A very low overpotential (−27 mV) with a very low internal resistance (7.104 Ω cm 2) is achieved with the fabricated microbial fuel cell (MFC) that has a modified 3D corrugated electrode. Thus, easier and faster charge transfer at the electrode−electrolyte interface is confirmed. The study presents a revolutionary practical approach in the development of highly efficient anode materials that can ensure easy scale-up for MFC applications.
Review on Material and Design of Anode for Microbial Fuel Cell
Energies, 2022
Microbial Fuel Cell (MFC) is a bio-electrochemical system that generates electricity by anaerobic oxidation of substrates. An anode is the most critical component because the primary conversion of wastewater into electrons and protons takes place on the surface of the anode, where a biofilm is formed. This paper describes the essential properties of the anode and classifies its types according to the material used to make it. Anode material is responsible for the flow of electrons generated by the microorganism; hence biocompatibility and conductivity can considered to be the two most important properties. In this paper, the various modification strategies to improve the performance of anodes of MFC are explained through the review of researchers’ published work in this field. The shape and size of the anode turned out to be very significant as the microbial growth depends on the available surface area. The attachment of biofilm on the surface of an anode largely depends on the inte...
Fuel Cells, 2014
Microbial fuel cells (MFCs) are an alternative electricity generating technology and efficient method for removing organic material from wastewater. Their low power densities, however, hinder practical applications. A primary limitation in these systems is the anode. The chemical makeup and surface area of the anode influences bacterial respiration rates and in turn, electricity generation. Some of the highest power densities have been reported using large surface area anodes, but due to variable chemical/physical factors (e.g., solution chemistry, architecture) among these studies, meaningful comparisons are difficult to make. In this work, we compare under identical conditions six micro/nano-structured anodes in micro-sized MFCs (47 μL). The six materials investigated include carbon nanotube (CNT), carbon nanofiber (CNF), gold/poly (ε-caprolactone) microfiber (GPM), gold/poly(ε-caprolactone) nanofiber (GPN), planar gold (PG), and conventional carbon paper (CP). The MFCs using three dimensional anode structures (CNT, CNF, GPM, and GPN) exhibited lower internal resistances than the macroscopic CP and two-dimensional PG anodes. However, those novel anode materials suffered from major issues such as high activation loss and instability for long-term operation, causing an enduring problem in creating widespread commercial MFC applications. The reported work provides an indepth understanding of the interplay between micro-/nanostructured anodes and active microbial biofilm, suggesting future directions of those novel anode materials for MFC technologies.
A comparative study of three types of anode electrodes in a microfluidic microbial fuel cell
2021
Microbial fuel cells (MFCs) are innovative bioelectrochemical approaches for the natural conversion of organic resources into energy based on the metabolic activities of inoculated bacteria that serve as biocatalysts. The main objective of the present study was to examine the effect of zinc foil modified with zinc oxide as a novel anode material to enhance power generation in a microfluidic MFC using oxalate as a substrate. X-ray diffraction and FE-SEM analyses were done for nanostructure confirmation and to understand the morphology of a zinc oxide-coated electrode. The microfluidic MFC performance was investigated and compared with a zinc foil and zinc foil linked stainless steel mesh through an external circuit. The experimental results expressed that the zinc foil, zinc foil externally linked stainless steel, and modified zinc foil as anode electrodes achieved the maximum power density of 2980 W m-3, 1080 W m-3, and 428 W m-3, respectively. The results demonstrated that the zinc...
Recent Progress of Nanostructure Modified Anode in Microbial Fuel Cells
Microbial fuel cell (MFC) is a bio-electrochemical system which converts chemical energy into electrical energy by catalytic activity of microorganisms. Electrons produced by microbial oxidation from substrates such as organic matter, complex or renewable biomass are transferred to the anode. Protons produced at the anode migrate to the cathode via the wire and combine with oxygen to form water. Therefore MFC technologies are promising approach for generating electricity or hydrogen gas and wastewater treatment. Electrode materials are one of the keys to increase the power output of MFCs. To improve the cost effective performance of MFCs, various electrodes materials, modifications and configurations have been developed. In this paper, among other recent advances of nanostructured electrodes, especially carbon based anodes, are highlighted. The properties of these electrodes, in terms of surface characteristics, conductivity, modifications, and options were reviewed. The applications, challenges and perspectives of the current MFCs electrode for future development in bio or medical field are briefly discussed.