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Specification of sulfate reducing bacteria biofilms accumulation effects on corrosion initiation
Author(s) -
Liu H.,
Huang L.,
Huang Z.,
Zheng J.
Publication year - 2007
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200603984
Subject(s) - biofilm , corrosion , sulfate reducing bacteria , dielectric spectroscopy , carbon steel , sulfate , x ray photoelectron spectroscopy , substrate (aquarium) , chemical engineering , chemistry , anaerobic corrosion , materials science , carbon fibers , electrochemistry , layer (electronics) , bacteria , metallurgy , composite material , electrode , biology , ecology , genetics , composite number , engineering
The accumulation process of sulfate reducing bacteria (SRB) biofilms established in anaerobic stagnant batch bioreactors on the surface of carbon steel and the nutrient transport and corrosion products distribution in it were characterized by X‐ray Photoelectron Spectroscopy (XPS). In addition, the corrosion occurrence and development of carbon steel under SRB biofilm was investigated by Electrochemical Impedance Spectroscopy (EIS) in‐situ. The results show that the thickness of SRB biofilms increases exponentially with time in the beginning and after 14 days reaches a maximum. From then on, the accumulation rate decreases to zero. In mature biofilms, SRB dispersed throughout the biofilm. In the inner layer near the substrate, due to the high sulfate‐reducing activity of SRB, corrosion products such S 2− , H 2 S and organic acid are present, which lead to corrosion occurrence and development. In the outer layer of the biofilm SRB can also reduce the SO 2− 4 to SO 2− 3 and S 2 O 2− 3 . This metabolism process enhances the Fe 2+ transfer from the inner to the outer side. The activity of SRB in the biofilm plays a key role in the initial corrosion process.