The effect and mechanism of a microbial agent used for corrosion control in circulating cooling water

Abstract

Corrosion control is vital for the safe operation of a circulating cooling water system. The biological method is a novel treatment method performed by adding a microbial agent to achieve corrosion control. In this study, microbial agents, including Bacillus cereus, Pseudomonas, Bacillus subtilis, and Thiobacillus denitrificans, were selected to investigate the anti-corrosion effect and mechanism of the biological method. The results indicated that the anti-corrosion efficiency of the microbial agent on Q235B carbon steel ranged from 8.06–9.02%, while that for 316L stainless steel was 62.80%. The anti-corrosion mechanisms of functional bacteria were also revealed, which included (a) the formation of a biofilm to isolate oxygen and corrosive substances, (b) the inhibition of a cathodic reduction reaction and reduction of corrosion current, and (c) the inhibition of sulfide corrosion.