Microbial influence on corrosion of copper in the repository environment Copper corrosion seminar, 15.12.2016 Aalto University, Otaniemi Leena Carpén, Pauliina Rajala, Elina Huttunen-Saarivirta, Maija Raunio, Malin Bomberg VTT Technical Research Centre of Finland Ltd Place for a photo (no lines around photo)
23
Embed
Microbial influence on Place for a photo (no lines around ...kyt2018.vtt.fi/copper_corrosion/Carpen.pdf · EFM- (electrochemical frequency modulation) measurements Gravimetric measurements:
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Microbial influence on
corrosion of copper in the
repository environment
Copper corrosion seminar, 15.12.2016
Aalto University, Otaniemi
Leena Carpén, Pauliina Rajala, Elina Huttunen-Saarivirta,
Maija Raunio, Malin Bomberg
VTT Technical Research Centre of Finland Ltd
Place for a photo
(no lines around photo)
219/12/2016 2
What is microbial corrosion?
Corrosion can be defined as the degradation of a material due to a
reaction with its environment
MIC = Microbially or microbiologically induced or influenced corrosion
Microbes or their metabolic by-products induce changes in chemical or
physical conditions
Microorganisms are able to accelerate several types corrosion such as:
general corrosion
localized corrosion
pitting and stress corrosion cracking
Anode:
M Mn+ + ne-
Cathode:
O2 + 2H2O +4 e- 4OH- or
2H+ + 2e- H2
Image: Mari Raulio
319/12/2016 3
Why to study MIC?
In oxygen-free water, the corrosion rate of steel and copper is low,
unless the water is very acidic or there is microbiological activity in the
environment
The groundwater contains up to 105 microbial cells mL-1 with
considerable species diversity
Microorganisms may significantly contribute to corrosion
by producing corrosive metabolic products
by consuming oxygen
by forming discontinuous accumulations
by oxidising iron(II) ions to iron(III) ions or manganese(II) to manganese(IV)
ions or ammonia to nitrites
by accelerating the electrochemical part reactions
The aim is to characterize biofilms associated with corrosion and the
ability of indigenous groundwater microbes to produce corrosive agents
419/12/2016 4
What is biofilm?
The activity of microorganisms attached to the
surfaces and the properties of formed biofilms
are essential factors when considering the
possibility of microbially induced corrosion
In aquatic environments microorganisms attach
to surfaces and form multispecies biofilms
Microbial cells in a biofilm differ from free living