Sulfate-reducing Bacteria On Marine Corrosion Behavior Of Influence

The relationship among the number of sulfate-reducing bacteria (SRB), the environment parameters and the corrosion behavior of carbon steel during the grown process of SRB; a kind of rapid detection method of SRB and its detection mechanisms; the influences of SRB on the oxygen reduction reaction are all studied by using multi-parameter Water Quality Monitor et al detection methods in this study.It is found that the main effects of the SRB growing process on the environment parameters are that the concentration of sulfide generated by the metabolisms of SRB increases quickly during the exponential phase and stabilizes during the death phase and the residual phase. The changes of redox potential during the SRB growing process are consistent with the changes of the sulfide concentration. The corrosion behavior of carbon steel in the study system containing SRB hardly relates on the active SRB number. But it depends on the accumulation of the metabolism products of SRB. And the anode process and the corrosion rate are accelerated during the exponential phase and stable during the death phase and the residual phase.The number of SRB can be detected out by measuring the potential of Ag electrod in the range of 50~10000ml-1 during 2~3 minutes. The adsorption of SRB and the metabolisms of SRB are the reasons for the decline of the Ag electrode potential.The cathodic oxygen reduction on glassy carbon (GC) electrode is O2 reduced into H2O via intermediates super-oxide ion (O2–) produced by 1-electron O2 reduction and hydrogen peroxide (H2O2) that produced by 2-electron O2 reduction and 1-electron O2– reduction. SRB catalyzed the decomposition of O2– and H2O2, which induced the increase of the cathodic oxygen reduction reaction current density.