“…Microbial bioanodes were produced at a constant potential of −0.1 V/SCE (i.e., electroanalytical system) from treated (A, E, and A + E) and non-treated (control) graphite electrodes, using the strict comparison method detailed and validated in Roubaud et al. (2019) ( Roubaud et al., 2019 ). Two successive experimental runs were performed with two different batches of dWW and activated sludge (AS) to duplicate the experimental results.…”
Section: Resultsmentioning
confidence: 99%
“…After 25 days of constant electrode polarization at −0.1 V/SCE, turn-over CVs were performed in dWW containing a concentration of 360 mg COD/L ( Figure 3 ). This concentration has already been experimentally validated to allow Jmax to be reached without dependence on the concentration of organic matter ( Roubaud et al., 2019 ). Figure 3 Cyclic voltammetry performed in dWW on treated graphite surfaces (A + E, A, E) and non-treated commercial graphite surface (Control) after microbial colonization (end of the 25-day experiment) Scan rate: 1 mV/s.…”
Section: Resultsmentioning
confidence: 99%
“…The predominant bacterial population of the Geobacteraceae family is actually very classical in the field of electroactive biofilms. Examples of diversity analysis on carbon-based anodic bioelectrodes (i.e., carbon cloth, graphite, modified graphite fiber) frequently report a majority of the Geobacteraceae family in biofilms from wastewater ( Kiely et al., 2011 ; Roubaud et al., 2019 ), marine estuarine sediments ( Holmes et al., 2004 ), the rhizosphere ( Kouzuma et al., 2013 ), or enriched from primary bioanodes ( Blanchet et al., 2015 ). All these cases have been shown independently with natural ( Holmes et al., 2004 ), industrial ( Blanchet et al., 2015 ) and model substrates such as acetate ( Kiely et al., 2011 ) and glucose ( Kouzuma et al., 2013 ).…”
Section: Resultsmentioning
confidence: 99%
“…The effects of the treatment protocols on the graphite surface were first evaluated from the standpoints of changes in topography (roughness [ Pocaznoi et al., 2012a ], specific surface [ Roberts and Slade, 2010 ]), evolution of the elemental and chemical composition (X-ray photoelectron spectroscopy [XPS]), and improvement of the electrochemical reactivity (material capacitance, electrochemically active surface). Then the treated electrodes were compared, under electroanalytical conditions (electrode potential and fuel concentration maintained at constant values [ Rimboud et al., 2014 ; Roubaud et al., 2019 ]), for their ability to act as dWW-fueled bioanodes. The current densities produced were compared with those of the control bioanodes (i.e., untreated graphite electrodes).…”
Summary
Acid and electrochemical surface treatments of graphite electrode, used individually or in combination, significantly improved the microbial anode current production, by +17% to +56%, in well-regulated and duplicated electroanalytical experimental systems.
Of all the consequences induced by surface treatments, the modifications of the surface nano-topography preferentially justify an improvement in the fixation of bacteria, and an increase of the specific surface area and the electrochemically accessible surface of graphite electrodes, which are at the origin of the higher performances of the bioanodes supplied with domestic wastewater. The evolution of the chemical composition and the appearance of C-O, C=O, and O=C-O groups on the graphite surface created by combining acid and electrochemical treatments was prejudicial to the formation of efficient domestic-wastewater-oxidizing bioanodes. The comparative discussion, focused on the positioning of the performances, shows the industrial interest of applying the surface treatment method to the world of bioelectrochemical systems.
“…Microbial bioanodes were produced at a constant potential of −0.1 V/SCE (i.e., electroanalytical system) from treated (A, E, and A + E) and non-treated (control) graphite electrodes, using the strict comparison method detailed and validated in Roubaud et al. (2019) ( Roubaud et al., 2019 ). Two successive experimental runs were performed with two different batches of dWW and activated sludge (AS) to duplicate the experimental results.…”
Section: Resultsmentioning
confidence: 99%
“…After 25 days of constant electrode polarization at −0.1 V/SCE, turn-over CVs were performed in dWW containing a concentration of 360 mg COD/L ( Figure 3 ). This concentration has already been experimentally validated to allow Jmax to be reached without dependence on the concentration of organic matter ( Roubaud et al., 2019 ). Figure 3 Cyclic voltammetry performed in dWW on treated graphite surfaces (A + E, A, E) and non-treated commercial graphite surface (Control) after microbial colonization (end of the 25-day experiment) Scan rate: 1 mV/s.…”
Section: Resultsmentioning
confidence: 99%
“…The predominant bacterial population of the Geobacteraceae family is actually very classical in the field of electroactive biofilms. Examples of diversity analysis on carbon-based anodic bioelectrodes (i.e., carbon cloth, graphite, modified graphite fiber) frequently report a majority of the Geobacteraceae family in biofilms from wastewater ( Kiely et al., 2011 ; Roubaud et al., 2019 ), marine estuarine sediments ( Holmes et al., 2004 ), the rhizosphere ( Kouzuma et al., 2013 ), or enriched from primary bioanodes ( Blanchet et al., 2015 ). All these cases have been shown independently with natural ( Holmes et al., 2004 ), industrial ( Blanchet et al., 2015 ) and model substrates such as acetate ( Kiely et al., 2011 ) and glucose ( Kouzuma et al., 2013 ).…”
Section: Resultsmentioning
confidence: 99%
“…The effects of the treatment protocols on the graphite surface were first evaluated from the standpoints of changes in topography (roughness [ Pocaznoi et al., 2012a ], specific surface [ Roberts and Slade, 2010 ]), evolution of the elemental and chemical composition (X-ray photoelectron spectroscopy [XPS]), and improvement of the electrochemical reactivity (material capacitance, electrochemically active surface). Then the treated electrodes were compared, under electroanalytical conditions (electrode potential and fuel concentration maintained at constant values [ Rimboud et al., 2014 ; Roubaud et al., 2019 ]), for their ability to act as dWW-fueled bioanodes. The current densities produced were compared with those of the control bioanodes (i.e., untreated graphite electrodes).…”
Summary
Acid and electrochemical surface treatments of graphite electrode, used individually or in combination, significantly improved the microbial anode current production, by +17% to +56%, in well-regulated and duplicated electroanalytical experimental systems.
Of all the consequences induced by surface treatments, the modifications of the surface nano-topography preferentially justify an improvement in the fixation of bacteria, and an increase of the specific surface area and the electrochemically accessible surface of graphite electrodes, which are at the origin of the higher performances of the bioanodes supplied with domestic wastewater. The evolution of the chemical composition and the appearance of C-O, C=O, and O=C-O groups on the graphite surface created by combining acid and electrochemical treatments was prejudicial to the formation of efficient domestic-wastewater-oxidizing bioanodes. The comparative discussion, focused on the positioning of the performances, shows the industrial interest of applying the surface treatment method to the world of bioelectrochemical systems.
“…Much effort has been invested into designing 3‐D anodes, developing carbon‐based polymer composites, coatings as well as conductive hydrogels and by selecting new graphite grades, which could sustain high performance in scaled‐up applications.…”
This study details, in‐depth, the development of graphite paper as electrodes, specifically anodes, for microbial electrochemical technologies. Processed natural graphite powders were used as an active filler substance in paper composites. Mechanical and electrical properties were balanced during development. Graphite papers with 80 wt% natural graphite content had tear lengths of 730±58 m and resistivities of 0.014±0.001 Ω cm. Electrochemically active biofilms on these materials, cultivated from biomass taken from the bioanodes of an already running bioelectrochemical reactor, were fed with acetate and yielded an average maximum current density of 0.855±0.135 as well as 0.489±0.148 mA cm−2 with a complex substrate mixture. All anodes exhibited similar performance to commonly used carbonaceous electrodes fed the same substrates. This places them as flexible and cheap electrode materials suitable for large‐scale microbial electrochemical technologies.
Microbial electrolysis cell (MEC) is a novel clean and green energy technology for biohydrogen production and simultaneously removes pollutants in terms of chemical oxygen demand, biological oxygen demand, total dissolved solids, colour, metal ions etc. from domestic, industrial and agricultural wastewater. MEC comprises of an anode and a cathode chamber separated by proton exchange membrane in which hydrogen is produced with the addition of a small electrical input (<1.2 V) due to the thermodynamic barrier. MEC is still in its inception stage and faces challenges in large-scale applications due to its design, electrodes, membrane cost, etc. In order to understand the applications of MEC, a review has been conducted to explore the various reactor configurations, including single and dual chamber, up-flow, packed bed, fluidized bed, and trickle bed reactors. In addition, basic principles, components required, MEC integrated with other bioelectrochemical system, challenges, pros and cons of reactor design have been discussed in this article. This review provides the advances and recent developments in research on MEC design, including mechanisms for real-time applications.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
