Enhancement of exogenous riboflavin on microbiologically influenced corrosion of nickel by electroactive Desulfovibrio vulgaris biofilm
Yanan Pu, Yuan Tian, Su Hou, Wenwen Dou, Shougang Chen
Abstract
Abstract Riboflavin, a soluble redox mediator for electron transfer, is involved in various redox processes in biogeochemical systems. This work gives some insights into the MIC mechanism of pure nickel (Ni) caused by Desulfovibrio vulgaris . Compared with pure copper (Cu) metabolite (M)-MIC, Ni MIC by D. vulgaris exhibits distinctly different corrosion behavior. 20 ppm (w/w) riboflavin dramatically enhances the corrosion rate of Ni (59% increase in weight loss), while it has no impact on Cu MIC. Furthermore, headspace H 2 detection reveals that neither proton nor H 2 S corrosion occurs in Ni MIC (Cu MIC caused by biogenic H 2 S produces large amounts of H 2 , whereas Ni MIC does not). The thermodynamic analysis and experimental results indicate that Ni D. vulgaris MIC is caused by trapping extracellular electrons from Ni oxidation for energy, which belongs to extracellular electron transfer (EET)-MIC.