Effect of adsorbed organic thin films on electrochemical interaction mechanisms of metal reducing bacteria with steel surfaces

  • The interface of a metal substrate and a biofilm can differ significantly from the surrounding environment. Metal reducing bacteria (MRB), for instance, are capable of utilizing various metallic compounds as electron acceptors. Besides chromium, uranium and manganese as well as many organic compounds, Fe(III) is converted to the soluble form Fe(II) during the bacterial metabolism. This could lead to a weakening of the protective passivation layer on stainless steel and thereby facilitate microbiologically influenced corrosion (MIC). Even tough the processes of electron transfer are not yet entirely explained, the contribution of flavins and other humic substances as electron shuttles is widely discussed in the literature. Moreover, the adsorption of organic thin films on steel surfaces can lead to surface preconditioning and thus to changes in adhesion behavior of bacteria. The aim of this work is to understand the chemical and electrochemical interaction mechanisms of MRB withThe interface of a metal substrate and a biofilm can differ significantly from the surrounding environment. Metal reducing bacteria (MRB), for instance, are capable of utilizing various metallic compounds as electron acceptors. Besides chromium, uranium and manganese as well as many organic compounds, Fe(III) is converted to the soluble form Fe(II) during the bacterial metabolism. This could lead to a weakening of the protective passivation layer on stainless steel and thereby facilitate microbiologically influenced corrosion (MIC). Even tough the processes of electron transfer are not yet entirely explained, the contribution of flavins and other humic substances as electron shuttles is widely discussed in the literature. Moreover, the adsorption of organic thin films on steel surfaces can lead to surface preconditioning and thus to changes in adhesion behavior of bacteria. The aim of this work is to understand the chemical and electrochemical interaction mechanisms of MRB with steel surfaces by combining electrochemistry and surface-analytical techniques. The investigations primarily focus on the effect of pre-adsorbed thin organic films and self-assembled monolayers (SAMs) on the electron transfer processes between bacteria and steel surfaces. Electrochemical Quartz Crystal Microbalance (eQCM) studies have been performed to investigate the adsorption/desorption kinetics of organic films as well as the formation of biofilms on FeCr electrodes. Furthermore, the evolution of the biofilms on steel surfaces has been analyzed by means of electrochemical impedance spectroscopy (EIS) to support the QCM studies with information on structural changes during different stages of biofilm growth. Electron transfer and corrosion processes have been analyzed by means of square wave voltammetry (SWV) and linear sweep voltammetry (LSV), respectively. The results of electrochemical studies are complemented with microscopic and spectroscopic characterisation of organic adsorbates and analysis of changes in the passive film chemistry and surface morphology. This presentation will summarize our results on the chemical and electrochemical interaction mechanisms of MRB on steel surfaces leading to passive film degradation. The role of flavins in accelerating corrosion processes will be elucidated in detail to provide useful insights from a fundamental aspect for the understanding of the initial stages of microbiologically influenced corrosion in the presence of MRB.zeige mehrzeige weniger

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Metadaten
Autoren/innen:Nina Wurzler
Koautoren/innen:Ana de Oliveira Guilherme Buzanich, Martin Radtke, Uwe Reinholz, Franziska Emmerling, Hans-Jörg Kunte, Ozlem Ozcan
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2017
Organisationseinheit der BAM:1 Analytische Chemie; Referenzmaterialien / 1.3 Strukturanalytik
4 Material und Umwelt / 4.1 Biologische Materialschädigung und Referenzorganismen
6 Materialschutz und Oberflächentechnik / 6.2 Grenzflächenprozesse und Korrosion
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurwissenschaften und zugeordnete Tätigkeiten
Freie Schlagwörter:Corrosion; Flavins; Metal reducing bacteria (MRB); Microbiologically influenced corrosion (MIC)
Themenfelder/Aktivitätsfelder der BAM:Material / Degradation von Werkstoffen und Materialien
Veranstaltung:232nd ECS Meeting
Veranstaltungsort:National Harbor, MD, USA
Beginndatum der Veranstaltung:01.10.2017
Verfügbarkeit des Volltexts:Volltext-PDF im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:15.12.2017
Referierte Publikation:Nein