Role of 2-mercaptopyridine on control of microbial influenced corrosion of copper CW024A metal in cooling water system

Abstract

In this present study, the biocorrosion behaviour of Bacillus thuringiensis EN2 and B. oleronius EN9 on copper metal CW024A (Cu) in cooling water system (1% chloride) were evaluated using weight loss, electrochemical impedance spectroscopy (EIS) and surface analysis. In presence of EN2 and EN9, the corrosion rates (CR) were higher, about 0.021 mm/y and 0.032 mm/y than control system (0.004 mm/y). On the other hand, the presence of corrosion inhibitor 2-mercaptopyridine (2-MCP) with bacteria (EN2 and EN9), the biofilm on metal surface was highly inhibited and thus reduces the corrosion rate (CR: 0.004 mm/y). The electrochemical behaviour of CW024A metal was correlated with the adsorbed corrosion inhibitor film and biofilm. Atomic force microscopy (AFM) analysis revealed that the presence of EN2 and EN9 more pits was observed on the metal surface rather than 2-MCP system. EIS confirms the inhibitor act as cathodic type of inhibitor and thus leads to the inhibition of CR. Overall, this work concluded that corrosion inhibitor (2-MCP) inhibits, the bacterial biofilm formation on the metal surface due to the formation of productive layer on metal surface as coordination of NH bond. Which leads to the reduction of bacterial attachment and thus higher corrosion inhibition efficiency (75%) obtained. This is the first work disclosing the role of 2-MCP formulations as potent anti-bacterial and corrosion inhibition efficiency on copper metal in cooling water tower environment.