Biofilm induced corrosion inhibition of Q235 carbon steel by anaerobic Bacillus cereus inoculum in simulated cooling water

Abstract In this study, corrosion behavior of Q235 carbon steel (CS) under Bacillus cereus (B. cereus) inoculum in simulated cooling water was evaluated. Weight loss study proved B. cereus inoculum possessed anti-corrosion efficiencies of 92.84% and 73.88% for 3 d and 14 d rotation tests respectively. The electrochemical measurements indicated added B. cereus inoculum increased the charge transfer resistance and reduced corrosion current density. The B. cereus cells with strong biofilm-forming capacity were able to adhere onto Q235 CS surface to form compact biofilms and cause biomineralization. Surface characterization analysis demonstrated the presence of B. cereus inoculum reduced the amount of Fe2O3 and simultaneously increased the amount of CaCO3 in corrosion products. The corrosion inhibition mechanisms of B. cereus inoculum involve forming biofilm, generating biomineralized layer, and consuming dissolved oxygen. Thus, B. cereus inoculum provides a biological strategy for the industrial cooling water anti-corrosion application.