Study On The Antibacterial Mechanism Of Cathodic Polarization

In the process of human development and utilization of ocean resources corrosion and biological fouling in seawater problem have always been the two major difficult problems. Impressed current cathode protection is not only the common use of the metal anti-corrosion technology, but also a kind of effective antifouling method. As a new antifouling technology, the mechanism of cathode protection has not yet been determined. Based on the numerical simulation combined with experiment, the purpose of this paper is to study the influence of impressed current cathode protection on biofilm and its mechanism.First, this paper using numerical simulation software simulated the formation of calcareous deposits on the surface of cathodically polarized steel in seawater and a variety of ion concentration changes near the surface. The thickness and coverage rate of calcareous deposits increase with time. The concentration of Ca2+, Mg2+decreases, while the concentration of OH-(pH) increases near the surface.Then, the adhesion of bacteria in the biofilm which stick to the surface of cathodically polarized specimen was studied. We found that there was no bacteria adhesion on the surface of cathodically polarized sample, which means that cathode protection can inhibit the adhesion of bacteria. The effects of different concentration of Ca2+、Mg2+and OH-on biofilm is studied. The results showed that the decrease of Ca2+and the increase of pH can significantly inhibit bacteria adhesion. While the decrease of Mg2+was in favor of the number of bacteria.Finally, the article used the electrochemical method to monitor the microbial membrane adhering on the surface of the304stainless steel. The electrochemical parameters changed. Found when sample surface has a microbial membrane adhesion of bacteria the life activities of bacteria causes oxygen concentration decreased on the surface of the sample. So the open circuit potential of the sample rised, polarization curves of the corrosion current density decreased, and Nyquist curve radius increased. And the same time immersing sterilization sample didn’t have these changes. These indicates that the bacteria metabolic activity in the microbial membrane not only enhances the304stainless steel corrosion resistance, but also can monitoring adhesion of microbial membrane on the surface of the specimen.