Corrosion of Q235 carbon steel induced by sulfate-reducing bacteria in groundwater: corrosion behavior, corrosion product and microbial community structure

Abstract

Microbiologically influenced corrosion (MIC) is one of the reasons leading to the service failure of pipelines buried in the soil. To investigate the effect of sulfate-reducing bacteria (SRB) on the corrosion behavior of Q235 carbon steel in groundwater, a hanging plate test was carried out and the SRB was characterized by electrochemical methods, surface analysis, and biological analysis. In addition, a group of blank experiments was used as a control. The results showed that SRB continued to grow and reproduce in groundwater without lacking a carbon source for 14d to maintain life activities. The community structure has changed after corrosion, and the dominant species of SRB has changed from Desulfovibrio to Desulfosporosinus. During the whole growth cycle, the electrochemical results demonstrated that the impedance of the carbon steel surface forming a biofilm was 1 order of magnitude higher than that of other periods, and the formed ferrous sulfide layer also hindered the occurrence of corrosion. In comparison to the condition without SRB, the inclusion of SRB results in reduced weight loss. The average weight loss with SRB is 0.01389 g, whereas the average weight loss without SRB is 0.03956 g. However, the 3D topography indicated that the surface of carbon steel was more uneven and pits were increased with SRB. Altogether these results implied that the growth of SRB makes the corrosion process of Q235 carbon steel more complicated.