Influence of nutrition on Cu corrosion by Desulfovibrio vulgaris in anaerobic environment

The eutrophication of seawater is not only harmful to the environment, but also influence microbes' proliferation and then influence biocorrosion of marine engineering materials to a great extent. This study investigated the microbiologically influenced corrosion (MIC) of Cu immersed in the Desulfovibrio vulgaris (a sulfate reducing bacterium) medium with four defined nutritional degrees: total nutrition, P lacking, N lacking, and P & N lacking. When D. vulgaris was cultured in more nutritional medium, more H2S was generated and more serious corrosion of Cu occurred. The concentration of H2S corresponding to the medium with total nutrition was as high as 4.9 x 10(4)(+/- 913.0) ppm. The weight loss of Cu in medium with total nutrition increased by at least 50% compared with other nutritional conditions. The depth of pitting pits on Cu increased obviously with more abundant nutrient elements N and P. The electrochemical tests supported the weight loss and also showed that an obvious passivation zone was formed on the anodic polarization curve. This indicated that a protective film was formed on the surface of Cu against uniform corrosion. The analyses of thermodynamics and experiment data indicated that metabolite MIC (MMIC) account for the Cu corrosion by D. vulgaris.(c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The eutrophication of seawater has harmful effects on the environment and microbes, which in turn affects the biocorrosion of marine engineering materials. This study investigated the microbiologically influenced corrosion (MIC) of Cu in the presence of Desulfovibrio vulgaris under different nutritional conditions. The results showed that more severe corrosion occurred when D. vulgaris was cultured in a more nutritional medium, resulting in the generation of higher concentrations of H2S. The study also found that the depth of pitting on Cu increased with higher levels of nutrient elements N and P.