The Nernst potential of the support/cell interface is suspected to play a key role in cell adhesion and proliferation. However, the studies that have addressed this topic have generally varied the electrochemical potential of the interface by comparing different materials or by varying the chemical composition of the surface coating. It is consequently hard to definitively separate the actual effect of the potential from possible side-effects due to differences in the surface composition or topography.
View Article and Find Full Text PDFAcid 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.
View Article and Find Full Text PDFThe influence of additional chemical molecules, necessary for the purification process of [Fe]-hydrogenase from Clostridium acetobutylicum, was studied on the anaerobic corrosion of mild steel. At the end of the purification process, the pure [Fe-Fe]-hydrogenase was recovered in a Tris-HCl medium containing three other chemicals at low concentration: DTT, dithionite and desthiobiotin. Firstly, mild steel coupons were exposed in parallel to a 0.
View Article and Find Full Text PDFBioanodes were formed with electrodes made of carbon felt and equipped with a titanium electrical collector, as commonly used in microbial fuel cells. Electrochemical impedance spectroscopy (EIS) performed on the abiotic electrode system evidenced two time constants, one corresponding to the "collector/carbon felt" contact, the other to the "carbon felt/solution" interface. Such a two time constant system was characteristics of the two-material electrode, independent of biofilm presence.
View Article and Find Full Text PDFPresent in all environments, microorganisms develop biofilms adjacent to the metallic structures creating corrosion conditions which may cause production failures that are of great economic impact to the industry. The most common practice in the oil and gas industry to annihilate these biofilms is the mechanical cleaning known as "pigging". In the present work, microorganisms from the "pigging" operation debris are tested biologically and electrochemically to analyse their effect on the corrosion of carbon steel.
View Article and Find Full Text PDFInfluence of sulfidogenic bacteria, from a North Sea seawater injection system, on the corrosion of S235JR carbon steel was studied in a flow bioreactor; operating anaerobically for 100days with either inoculated or filtrated seawater. Deposits formed on steel placed in reactors contained magnesium and calcium minerals plus iron sulfide. The dominant biofilm-forming organism was an anaerobic bacterium, genus Caminicella, known to produce hydrogen sulfide and carbon dioxide.
View Article and Find Full Text PDFA procedure was proposed to mimic marine microbial fuel cell (MFC) in liquid phase. A graphite anode and a stainless steel cathode which have been proven, separately, to be efficient in MFC were investigated. A closed anodic compartment was inoculated with sediments, filled with deoxygenated seawater and fed with milk to recover the sediment's sulphide concentration.
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