Biofilm-Induced Corrosion Inhibition of Q235 Carbon Steel by Tenacibaculum mesophilum D-6 and Bacillus sp. Y-6

The corrosion of carbon steel causes dramatic economic losses each year. Since conventional corrosion prevention approaches may cause pollution problems to the environment, ecofriendly and effective corrosion approaches are desired. Microbiologically influenced corrosion inhibition (MICI) has been reported as a sustainable corrosion prevention method. This work aims to evaluate the corrosion inhibition effect of two bacterial strains,Tenacibaculum mesophilumD-6 andBacillussp. Y-6 by choosing Q235 carbon steel as a model system. Scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and a series of electrochemical techniques were applied to study the corrosion prevention effect. The electrochemical and pitting results indicated thatT. mesophilumD-6 displayed a better corrosion protection effect.T. mesophilumD-6 formed a denser and thicker biofilm on the Q235 surface thanBacillussp. Y-6. The maximum thickness of theT. mesophilumD-6 biofilms was 11.6 ± 0.7 μm, which is about twice as thick than that ofBacillussp. Y-6. The corrosion prevention mechanism was ascribed to the formation of biofilms as a barrier to block corrosive agents such as O2. This study provides a theoretical foundation for the application of biofilms as green and effective corrosion inhibitors for carbon steel.Keywords:Q235 carbon steel;Tenacibaculum mesophilumD-6;Bacillussp. Y-6;corrosion inhibition;biofilm formation ability