The Study Of Corrosion Mechanism Induced By Sulphate Reducing Bacteria And Composite Antibacterial Mateirals

As a lot of marine engineering facilities and equipment has been put intoapplication, two major problems have to be faced inevitably: marine metal corrosionand marine biofouling and they often occur at the same time and have mutualinfluence. Thereafter, it is of great theoretical and practical importance to study themechanism of marine metal corrosion and marine biofouling and their preventionmethods.In this work, the effects of two main metabolites of sulfate-reducing bacteria,sulfide and extracellular polymeric substances (EPS) on Q235carbon steels in3.5%NaCl solution have been studied separately. Attenuated total reflectance fouriertransform infrared spectra (ATR-IR) and in situ atomic force microscopicmeasurements (AFM) with a liquid cell coupled with potentiodynamic polarisationcoupled with potentiodynamic polarization and electrochemical impedancespectroscopy have been used to studied the effects of EPS. Microbiologicallyinfluenced corrosion (MIC) induced by SRB was mainly caused by sulfide and EPSonly provide the feeble protective effect after16d of immersion.Chitosan hydrogel loaded with the well-known corrosion inhibitor2-mercaptobenzothiazole has been introduced into a composite coating to improvecopper protection by combining a simple self-assembled monolayer technique with asol-gel method. The anti-corrosion ability of the coating in3.5wt.%NaCl solutionwas investigated by potentiodynamic polarization and electrochemical impedancespectroscopy. The stability and integrity of the composite coating were also evaluated.The results suggest that the composite coating endows the copper substrate withanti-corrosion property in seawater and provide a certain protection against MICinduced by SRB.In order to increase the antibacterial efficiency, we have impregnated graphene oxide (GO) nanosheets with silver nanoparticles (Ag NP) and fabricated a novelantibacterial composite material. The morphology of Ag NP/GO composites werecharacterized by Electron Microscope (TEM) andElectron Diffraction. The as-prepared composites could kill106colony forming unitsEscherichia coli (E.coli) completely and exhibit a certain antibacterial activity toStaphylococcus aureus (S.aureus) a representative strain of Gram positive bacteria atthe same time.