scholarly journals Characterization of sulphate-reducing bacteria as a function of time on buried pipeline steel under cathodic protection

2021 ◽  
Vol 39 (4) ◽  
pp. 225-236
Author(s):  
K Khoele ◽  
O M Ama ◽  
D J Delport
Keyword(s):  
Cathodic Protection ◽  
Pipeline Steel ◽  
Buried Pipeline ◽  
Sulphate Reducing Bacteria ◽  
Reducing Bacteria

scholarly journals Study of the Fe(II-III) hydroxysalts transformation according to the pH and the concentration of the ions present

2018 ◽  
Vol 7 (5) ◽  
pp. 359-369
Author(s):  
Farida Termemil ◽  
Marwa Ahmed-Malek ◽  
Assia Bourouba ◽  
Mohamed-rida Benloucif
Keyword(s):  
Carbon Steel ◽  
Cathodic Protection ◽  
Iron Hydroxide ◽  
Green Rust ◽  
Corrosion Products ◽  
Water Molecules ◽  
Marine Environments ◽  
Sulphate Reducing Bacteria ◽  
Reducing Bacteria ◽  
Ordinary Steel

Sulphated green rust, GR (SO4 2- ), is one of the main corrosion products of carbon steel in marine environments. It is Fe (II)-Fe(III) hydroxylsalt in sheets, consisting of alternating layers of iron-hydroxide type Fe(OH)2 , loaded positively due to the presence of the cations Fe(III) and negative interlayers consisting of anions and water molecules. This compound is strongly associated with the metabolism of sulphate-reducing bacteria, and can also evolve under cathodic protection. Thus, recently, GR (CO3 2- ) has been detected in place of GR (SO4 2- ) on already corroded ordinary steel, newly subjected to cathodic protection. This presence is due to the pH and[SO4 2−] [HCO3 − ⁄ ] conditions imposed by the cathodic protection. In this paper, we chemically synthesize sulfated and carbonate green rust in a chlorinated medium; we then study their respective transformation according to the concentration [SO4 2- ] / [HCO3 - ] ratio and pH. Our results show that from a GR (SO4 2- ), GR (CO3 2- ) is formed from a pH ≥8.2 for [SO4 2- ] / [HCO3 - ] = 12 and without any change in pH for [SO4 2- ] / [HCO3 - ] <12. Whereas from GR (CO3 2- ), GR (SO4 2- ) is formed for [SO4 2- ] / [HCO3 - ] > 1 without any change in pH.

Effects of sulphate-reducing bacteria on crevice corrosion in X70 pipeline steel under disbonded coatings

2015 ◽  
Vol 101 ◽  
pp. 1-11 ◽  
Author(s):  
Xu Chen ◽  
Guanfu Wang ◽  
Fengjiao Gao ◽  
Yanliang Wang ◽  
Chuan He
Keyword(s):  
Crevice Corrosion ◽  
Pipeline Steel ◽  
X70 Pipeline Steel ◽  
Sulphate Reducing Bacteria ◽  
Reducing Bacteria
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