Microbial corrosion of N-heterocyclic carbene-enhanced coated mild steel
Abstract
Microbial-influenced corrosion (MIC) has been reported to cause structural damage in pipelines. Epoxy coats can mitigate corrosion but delaminate over time. N-heterocyclic carbenes (NHC) can potentially increase adhesion between epoxy coats and metals. This research investigated the effectiveness of NHC-enhanced epoxy-coated mild steel against MIC. Initial experiments evaluated various media to determine conditions that promoted mild steel corrosion when exposed to Escherichia coli ATCC 25922. E. coli in M9 medium increased corrosion, while in LB medium, corrosion was inhibited. In subsequent experiments, two types of epoxy-coated and epoxy-NHC-coated mild steel were exposed to E. coli in M9 and LB media. Measurements of dissolved iron, oxidation levels, and surface observations showed that E. coli increased corrosion, but the addition of NHC did not reduce MIC. NHC may prevent corrosion under less corrosive experimental conditions, with a different type of epoxy coating, or in the presence of more environmentally relevant bacteria.