Influence of riboflavin on the corrosion of X80 pipeline steel by Sulfate reducing bacteria

The sulfate reducing bacteria(SRB) is commonly attached to the surface of buried pipeline steel, and the electron shuttle in the corrosion medium can promote the release of electrons from iron oxidation through the bacterial cell wall into the cytoplasm to accelerate the corrosion of anode iron. This study investigated the impact of riboflavin (RF) as an endogenous electron shuttle on the corrosion behavior of X80 pipeline steel in SRB system. The findings indicated that while the type of corrosion products remains unchanged in samples under SRB+10 mg l-1 RF system, there was an expansion in both area and depth of corrosion pits on the sample surface, resulting in a corrosion loss rate approximately 3 times higher than that observed in SRB system. Furthermore, the polarization resistance (Rp) value of the sample in SRB system is about 2 similar to 5 times that of the sample in SRB+10 mg l-1 RF system. Additionally, the corrosion current density of X80 pipeline steel samples soaked in SRB and SRB +10 mg l-1 RF system for 14 days is 9.31 x 10-6 A<middle dot>cm-2 and 1.28 x 10-5 A<middle dot>cm-2, and the addition of 10 mg l-1 RF increases the corrosion current density of SRB system by about 37.49%. These results indicated that the reaction resistance of SRB-induced MIC in X80 pipeline steel was significantly reduced due to the presence of RF.