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Microbiologically influenced corrosion of carbon steel caused by a sulfate reducing bacterium

Chen, Yajie
http://orcid.org/0000-0002-3992-1777
http://rave.ohiolink.edu/etdc/view?acc_num=akron1468357213

Abstract Details

2016, Doctor of Philosophy, University of Akron, Chemical Engineering.
Sulfate reducing bacteria (SRB) are common culprits of microbiologically influenced corrosion (MIC) that has been reported to cost $138 billion annually in the United States. Most literature reported the study results of SRB-induced corrosion when organic nutrients were provided to bacteria. But SRB-metabolizable organic substrates are not always available in the field conditions. There is a clear need to identify how SRB can induce pitting under the condition of long term starvation of organic substrates. The goals of this work are to elucidate the corrosion mechanisms of organic starving SRB on carbon steel (C1010) and propose possible MIC mitigation approaches. The specific objectives are: (1) monitoring MIC by correlating results of electrochemical impedance spectroscopy (EIS) and potential difference (PD) with measurements of bioactivities, biofilm and corrosion deposits; (2) development of a faster methodology for pit characterization to significantly reduce characterization time; (3) explication of the survival and corrosion mechanisms of a well-known SRB, D. vulgaris under long term starvation; and (4) development of possible MIC mitigation approaches. Coupons and sulfate-reducing biofilms were examined by confocal laser scanning microscopy (CLSM), infinite focus microscopy (IFM), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). Bioactivities in the liquid phase were measured by high-performance liquid chromatography (HPLC) and various biological assays. Metal-biofilm interfacial layer evolution was monitored by EIS and PD. Our results supported the following conclusions: (1) EIS may be used for online monitoring of biofilm and corrosion product evolution, but the signals are complicated and require more systematic studies to improve understanding and ensure correct interpretation. Under certain conditions, pitting occurrence might be detectable from inner layer porous resistance and PD profiles. (2) Empirical correlations that enable fast estimation of maximum and average pit depths and pitted area percentage from the standard 3D surface parameters obtainable with IFM were established. (3) D. vulgaris, a common H2-utilizing SRB can survive on carbon steel up to 46 days under organic starvation by coupling direct electron uptake from steel surface with sulfate reduction. Direct cell attachment to metal is essential for this survival mechanism and the resultant pitting corrosion. (4) Future mitigation approach should target at preventing direct cell attachment or killing all the cells of biofilm including innermost layer of cells. KH2PO4 was demonstrated to be a promising MIC inhibitor by significant reduction of sessile SRB number and inhibition of pitting and intergranular corrosion.
Lu-Kwang Ju (Advisor)
Bi-min Zhang Newby (Committee Member)
Gang Cheng (Committee Member)
John Senko (Committee Member)
Christopher Miller (Committee Member)
285 p.
Chemical Engineering; Materials Science; Metallurgy; Microbiology
microbiologically influenced corrosion; sulfate reducing bacteria; infinite focus microscopy; pitting corrosion; intergranular corrosion; confocal microscopy; impedance spectroscopy; Desulfovibrio vulgaris; biofilm; biocorrosion; carbon steel; roughness

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Citations

  • Chen, Y. (2016). Microbiologically influenced corrosion of carbon steel caused by a sulfate reducing bacterium [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468357213

    APA Style (7th edition)

  • Chen, Yajie. Microbiologically influenced corrosion of carbon steel caused by a sulfate reducing bacterium. 2016. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1468357213.

    MLA Style (8th edition)

  • Chen, Yajie. "Microbiologically influenced corrosion of carbon steel caused by a sulfate reducing bacterium." Doctoral dissertation, University of Akron, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1468357213

    Chicago Manual of Style (17th edition)

akron1468357213
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This open access ETD is published by University of Akron and OhioLINK.