Characterizations of the biomineralization film caused by marine Pseudomonas stutzeri and its mechanistic effects on X80 pipeline steel corrosion

Abstract

• Marine pseudomonas stutzeri is isolated and identified. • P. stutzeri can promote the formation of a protective biomineralization film. • The biomineralization film has a good inhibition effect against steel corrosion. • The inhibition effect is related to the initial cell concentrations of P. stutzeri . • A novel strategy of preparing nano iron oxides by steel corrosion is put forward. Microbiologically influenced corrosion (MIC) of steel generates a corrosion product film, which can also be called biomineralization film. It is critical to understand the structure of biomineralization film since it dominates the corrosion behavior of metal. In this work, Pseudomonas stutzeri ( P. stutzeri ) was isolated from seawater, and the biomineralization film caused by marine P. stutzeri was characterized by Transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. The mechanistic effects of the biomineralization film on X80 pipeline steel corrosion were also investigated. The results indicate that the minerals are mainly composed of nano Fe 3 O 4 and FeOOH, according to TEM and XRD results. The particle sizes of biominerals are below 10 nm. This work also provides an insight strategy to prepare nanomaterials by MIC caused by P. stutzeri . In addition, P. stutzeri can grow well with CO 2 as a carbon source and iron as an electron donor. The corrosion rates (CRs) of specimens are closely related to the structure of biomineralization film. The CRs increase with the decrease of initial cell concentration. P. stutzeri with an initial concentration of 10 7 cells/mL can promote the formation of a compact biomineralization film with a thickness of 145.8 ± 4.8 μm, leading to corrosion inhibition with a CR of 0.058±0.008 mm/y. But some corrosion pits can be observed due to the formation of small anodes. Electrochemical impedance spectroscopy (EIS) data show higher impedance values and two time-constants, which imply the formation of a compact biomineralization film.