The combination of HEDP and D-phenylalanine inhibits methanogens-mediated corrosion

Abstract

Methanogens are one of the main species that cause metal corrosion in pipelines via forming biofilm, which greatly reduce the role of corrosion inhibitors and thus increase their dosages. D-amino acids can inhibit the formation of biofilm, which might be an effective strategy to improve the conventional corrosion inhibitors. However, little literature reported the synergistic effects of corrosion inhibitors and D-amino acids on methanogens-mediated corrosion. Therefore, 1-hydroxyethane-1,1-diphosphonic acid (HEDP) was chosen as a typical corrosion inhibitor and D-Phenylalanine (D-Phe) as a D-amino acid to evaluate their roles in corrosion caused by Methanosarcina barkeri. D-Phe and HEDP can synergistically inhibit microbiologically influenced corrosion, reducing corrosion rate by 89.66 % and effectively mitigating corrosion on carbon steel surfaces. Besides, HEDP and D-Phe can retard the cathodic reaction and thus reduce the corrosion rate. Also, the protein content in biofilm obviously decreased in the presence of HEDP and D-Phe, which was only 2.44 % of that in blank group. Furthermore, the addition of HEDP and D-Phe resulted in the down-regulation of the genes MSBRM_RS06090, MSBRM_RS13790, and MSBRM_RS13820, which are related to extracellular protein secretion and biofilm formation, thus making it difficult for M. barkeri to aggregate and form biofilms. This study provides a new approach to enhance conventional corrosion inhibitors, mitigate microbiologically influenced corrosion and alleviate eutrophication of water bodies.