Multifunctional Inhibitor Mixture for Reducing Bacteria Growth and Corrosion on Marine Grade Steel

Abstract

<p><a></a>High strength steel in marine environments suffers from severe corrosion susceptibility and the presence of bacteria can exacerbate the effect, accelerating degradation via microbiologically influenced corrosion (MIC). Here we propose a novel approach to MIC inhibition by designing a system capable of limiting the effects of both bacteria growth and corrosion. The combination of a newly synthesised compound, cetrimonium 4-hydroxycinnamate, with lanthanum 4-hydroxycinnamate was the only system tested to date that could both inhibit abiotic corrosion in artificial seawater and minimise bacteria consortium densities over an exposure period of 24 hours. </p> <p>The electrochemical data for the La+Cet mixture demonstrated the significant inhibition of both abiotic corrosion to a level similar to La(4OHCin)<sub>3</sub>, as well as the ability to reduce bacteria densities of single strains and a consortium. This is unlike the La+CetNal mixture which accelerated abiotic corrosion and the La+IMI which had an insignificant effect on microbial densities (Catubig et al. 2020). </p> <p>A compatible mixture of ionic inhibitors was achieved by using the same cinnamate anion. </p> <p>This mixture of Cet-4OHCin and La(4OHCin)<sub>3</sub> demonstrated significant abiotic corrosion inhibition and bacteria density reductions, making it a strong candidate as an MIC inhibitor system for 80HLES. </p> <p>The Cet-4OHCin compound and its mixture with La(4OHCin)<sub>3</sub> retained relatively low sensitivity towards skin and intestinal cells, making it a safer and more attractive alternative than other more hazardous corrosion inhibitor materials. </p>