News & Events
Anaerobic Microbial Influence Corrosion due to Methanogens
Speaker(s): A/Prof. Daniel J. Blackwood, Deputy Head for Education, Department of Materials Science & Engineering, National University of Singapore
When: 02 August 2017 (4:00 - 5:00pm)
Where: Asian School of the Environment (ASE) Seminar Room (N2-01B-28)
Type: Seminars

Abstract

The vast majority of cases of anaerobic microbial influence corrosion (MIC) are linked to the presence sulphate reducing bacteria (SRB), with the most credible mechanism being that the H2S these SRB produced reacts with the steel to form a non-passivating layer of FeS. It is thought that the semi-conductive FeS layer is more conducive for the kinetics of the hydrogen evolution reaction thus creating an extended cathode and causing accelerated corrosion in a manner akin to galvanic corrosion. Nevertheless, there are a growing number of reports of MIC in the absence of SRB, with the culprit in these cases thought to be archaea methanogens that produce methane as a metabolic by-product in anoxic conditions. However, unlike SRB, methanogens do not produce H2S so the extended FeS cathode mechanism cannot be applied in these cases. Furthermore, here it is demonstrated that if all sources of H2S are removed, the methanogenic strain Methanosarcina barkeri only caused accelerated corrosion when deprived of traditional energy sources for methanogenesis, such as methanol and H2. Possible mechanisms for this phenomenon of starvation conditions triggering accelerated corrosion are discussed.

Biography 

Daniel J. Blackwood is currently deputy head for education in the Department of Materials Science & Engineering, National University of Singapore, where he has been since 1996. He obtained his PhD degree in Electrochemistry under Prof. Laurie Peter (University of Southampton 1986). He was a postdoc at University of Utah where he worked on developing FTIR techniques for exploring the electrochemical interface. In 1989 he received an Alexander von Humboldt fellowship to work at the Universität der Bundeswehr München on conducting polymer vapour sensors. In 1990 he joined the United Kingdom Atomic Energy Authority at Harwell Laboratories as a project manager in the aqueous corrosion section. Daniel is a fellow of the Royal Society of Chemistry, and a member of the National Association of Corrosion Engineers and the international Society of Electrochemist. His current research interests are in the fields of aqueous corrosion, lithium-air batteries and inorganic electrochromic windows.