University of Calgary,
Keywords: microbiologically influenced corrosion, biofilm, oil, gas
Summary:Microbiologically influenced corrosion (MIC) has been one of the primary mechanisms resulting in detrimental effects on steel structures and facilities in oil production and transportation. Statistics show that MIC is responsible for nearly 50% of corrosion scenarios in oil pipelines. It is generally accepted that bacterial attachment is the first step for the formation and growth of biofilm, resulting in MIC and, particularly, pitting corrosion, of the steels. Of various microorganisms that can adhere to metals (steels), sulfate reducing bacteria (SRB), one type of anaerobic bacteria using sulphate as a terminal electron acceptor to degrade organic compounds, are widely spread in environments and easily form a biofilm on the steel surface. It is estimated that corrosion loss induced by SRB accounts for over 50% of all MIC. Development of high-performance, environmentally friendly techniques for detection and prevention of SRB attachment to the steel is essential for MIC-preventive asset integrity management. This work includes the latest research accomplishments made in author’s laboratory in SRB detection and anti-adhesion of the biocells to steel based on nanotechnology. An electrochemical biosensor based on 3-dimensional graphene/gold nanoparticles was developed for SRB detection. The technique combined the high selectivity of nucleic acid hybridization by genetic marker with the high sensitivity of electrochemical analytical method for the purpose. Processing parameters were optimized to maximize the detection capability, and various testing and analysis techniques were used to characterize the performance of the biosensor. Upon effective detection of the SRB in the service environments, the further work is to control adhesion of the biocells to steel surface for biofilm formation and MIC occurrence. A one-step anodization technique was developed to nanopattern the steel in alkaline solutions. The homogeneous, compact nanostructured surface of the steel possesses the satisfactory hydrophobicity and anti-adhesion performance to SRB. The technique is simple, economic and environment-friendly, providing a promising approach for industry-area fabrication to potentially replace conventional anti-bacterial methods such as chemical treatment program.