The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes
Includes bibliographical references. === The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since...
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University of Cape Town
2015
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Online Access: | http://hdl.handle.net/11427/12327 |
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ndltd-netd.ac.za-oai-union.ndltd.org-uct-oai-localhost-11427-123272020-07-22T05:07:30Z The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes Costello, John Anthony Liesegang, E C Theoretical Chemistry Includes bibliographical references. The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since it occurs in the absence of oxygen, at more or less neutral pH values and at ordinary ambient temperatures. The hypothesis of von Wolzogen Kuhr and van der Vlugt, published in 1934, proposing that enzymic catalysis of sulphate reduction by cathodic charge constituted a "cathodic depolarizing" process, which appears t o be widely accepted as the most likely mechanism for this corrosive effect, is evaluated critically here in the light of established electrochemical and biochemical knowledge. The theoret ical arguments presented in this thesis show that this process, if it does occur, is unlikely to affect corrosion rates. The experimental results presented here indicate that all cathodic depolarizing activity demonstrated in pure cultures of these organisms is attributable to the cathodic activity of dissolved hydrogen sulphide produced by the organisms. The conclusions of other workers, quoted in support of proposed enzymic catalysis of charge transfer from cathodes to redox dyes in laboratory systems, are considered, in view of experimental work performed during this investigation, to be a misinterpretation of experimental results. 2015-01-27T10:05:04Z 2015-01-27T10:05:04Z 1975 Doctoral Thesis Doctoral PhD http://hdl.handle.net/11427/12327 eng application/pdf University of Cape Town Faculty of Science Department of Chemistry |
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English |
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Doctoral Thesis |
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Theoretical Chemistry |
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Theoretical Chemistry Costello, John Anthony The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
description |
Includes bibliographical references. === The mechanism of the corrosive action of sulphate reducing bacteria of the genus Desulfovibrio towards ferrous metals has been investigated. This corrosive action is anomalous when considered in the light of established knowledge of corrosion processes, since it occurs in the absence of oxygen, at more or less neutral pH values and at ordinary ambient temperatures. The hypothesis of von Wolzogen Kuhr and van der Vlugt, published in 1934, proposing that enzymic catalysis of sulphate reduction by cathodic charge constituted a "cathodic depolarizing" process, which appears t o be widely accepted as the most likely mechanism for this corrosive effect, is evaluated critically here in the light of established electrochemical and biochemical knowledge. The theoret ical arguments presented in this thesis show that this process, if it does occur, is unlikely to affect corrosion rates. The experimental results presented here indicate that all cathodic depolarizing activity demonstrated in pure cultures of these organisms is attributable to the cathodic activity of dissolved hydrogen sulphide produced by the organisms. The conclusions of other workers, quoted in support of proposed enzymic catalysis of charge transfer from cathodes to redox dyes in laboratory systems, are considered, in view of experimental work performed during this investigation, to be a misinterpretation of experimental results. |
author2 |
Liesegang, E C |
author_facet |
Liesegang, E C Costello, John Anthony |
author |
Costello, John Anthony |
author_sort |
Costello, John Anthony |
title |
The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
title_short |
The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
title_full |
The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
title_fullStr |
The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
title_full_unstemmed |
The mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
title_sort |
mechanism of cathodic depolarization exhibited by sulphate-reducing bacteria during metallic corrosion processes |
publisher |
University of Cape Town |
publishDate |
2015 |
url |
http://hdl.handle.net/11427/12327 |
work_keys_str_mv |
AT costellojohnanthony themechanismofcathodicdepolarizationexhibitedbysulphatereducingbacteriaduringmetalliccorrosionprocesses AT costellojohnanthony mechanismofcathodicdepolarizationexhibitedbysulphatereducingbacteriaduringmetalliccorrosionprocesses |
_version_ |
1719330037508866048 |