School of Engineering, RMIT University , GPO Box 2476, Melbourne, Victoria 3001, Australia.
Manufacturing, CSIRO , Research Way, Clayton, Victoria 3168, Australia.
Environ Sci Technol. 2017 Aug 1;51(15):8501-8509. doi: 10.1021/acs.est.7b00437. Epub 2017 Jul 12.
Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.
埋地钢基础设施可为细菌种类提供铁离子，导致微生物影响的腐蚀（MIC）。由于 MIC 导致的管道局部腐蚀是埋地钢管道失效的关键机制之一。为了更好地理解土壤中局部腐蚀的机制，已经开发出半固态琼脂作为土壤的模拟物。在这里，引入了荧光假单胞菌以了解细菌与钢的相互作用。通过包括开路电位、动电位扫描、阳极电位保持和电化学阻抗谱在内的电化学测试表明，荧光假单胞菌会增加腐蚀速率。氧化物和生物膜形成的时间似乎不会影响腐蚀速率，但会改变生物膜的一致性，以及电化学测试后荧光假单胞菌的生存能力。碳钢腐蚀速率增加的机理涉及到绿脓菌素与钢的相互作用，在初始细胞附着后阻止了有凝聚力的钝化层的形成，随后在钢表面形成金属浓度梯度。
