An exopolysaccharide substances produced by Vibrio neocaledonicus sp. was introduced as a novel green inhibitor against the corrosion of carbon steel in artificial seawater and acidic media. The produced extracellular...An exopolysaccharide substances produced by Vibrio neocaledonicus sp. was introduced as a novel green inhibitor against the corrosion of carbon steel in artificial seawater and acidic media. The produced extracellular polymeric substance（EPS） is heterogeneous with composition of polysaccharides, nucleic acids and protein and average molecular weight of 29,572 Da. Adsorption of EPS on the metal surfaces and formation of Fe-EPS complexes acted as a barrier to prevent the oxygen penetration and hindered anodic and cathodic reactions. The inhibitory effect increases with increasing EPS concentration and exposure time. The highest corrosion inhibitory effect（95.1%） was observed for 10 g/L of EPS after 5 days of exposure in seawater. This is the highest inhibitory effect ever been reported by EPSs. While, the optimum concentration of EPS with the highest inhibition efficiency in 1 N H;SO;was 1000 ppm. The influence of different parameters, such as initial pH, growth phase, various nitrogen and carbon sources on the production of EPS and its corrosion inhibitory effect were also investigated. According to results,the optimum culture medium for EPS production is contained artificial seawater including 5% mannitol as carbon source and 0.1%（NH;）;SO;as nitrogen source at pH = 8. This medium could produce 22.24 g/L EPS during 3 days’ incubation at 30 ℃. The corrosion inhibitory efficiency of obtained EPS was 95.97%.展开更多
Complex interactions within a microbial consortium can induce severe corrosion in oil pipelines.This study investigated the mechanism of microbiologically influenced corrosion(MIC)that led to failure of X52 steel pipe...Complex interactions within a microbial consortium can induce severe corrosion in oil pipelines.This study investigated the mechanism of microbiologically influenced corrosion(MIC)that led to failure of X52 steel pipelines after hydrostatic testing.Laboratory hydrostatic testing with untreated lake water and underground water were used to simulate and study the events that led to the actual corrosion.Biofilm analysis,weight loss,and several electrochemical measurements demonstrated rapid corrosion rates after hydrostatic testing.Analysis of microbial community structures revealed that methanogenic archaea and sulfate reducing bacteria(SRB),introduced by the hydrotest water,formed corrosive biofilms on X52 steel coupon surfaces that induced severe pitting.展开更多
The effects of low electromagnetic field (EMF)(B = 2 mT) on the corrosion of pure copper in the absence and presence of multispecies marine aerobic bacteria were investigated in this work. The results showed that EMF ...The effects of low electromagnetic field (EMF)(B = 2 mT) on the corrosion of pure copper in the absence and presence of multispecies marine aerobic bacteria were investigated in this work. The results showed that EMF has an inhibitory effect on copper metals and decreases the corrosion rate of copper metals in sterile artificial seawater. However, microbiologically influenced corrosion of Cu was increased in the presence of electromagnetic field due to its effect on the biofilm morphology and structure. EMF reduced the growth rate of bacteria and decreased bacterial attachment, thereby forming a heterogeneous and non-stable biofilm on the Cu surface in the presence of EMF. Moreover, the biofilm was dispersed throughout the surface after 7 days, whereas the scattered bacteria were observed on the surface after 10 days. Confocal laser scanning microscopy images showed large and deep pits on the surface in the presence of EMF and confirmed the acceleration of Cu corrosion in the presence of EMF and multispecies bacteria. Furthermore, XPS and FTIR results demonstrated that the corrosion products and metabolic by-products were significantly changed in the presence of EMF.展开更多
Multi-species biofilms are found in various bacterial habitats and have industrial relevance. These complex bacterial communities have synergetic effects, unlike a single species. Therefore, it is critical to evaluate...Multi-species biofilms are found in various bacterial habitats and have industrial relevance. These complex bacterial communities have synergetic effects, unlike a single species. Therefore, it is critical to evaluate these complex communities as a whole. Here, the inhibitory eff ect of single-and dual-species biofilms of Vibrio neocaledinocus sp. and Pseudoalteromonas piscicida for A36 carbon steel corrosion was investigated. The results demonstrated that the synergistic interactions of the monoculture increased the overall biomass production of the dual-species biofilm, but the growth rate was reduced in the presence of the dual-species culture due to a lack of nutrients. Field emission scanning electron microscopy images also confirmed the development of biofilms—they became more homogenized via exposure time in both the mono-and dual-species cultures. The corrosion resistance of A36 carbon steel positively increased because of the dual-species interactions. This reached the highest value after four weeks of exposure. The highest corrosion inhibition e fficiency of 99.8% was achieved in the dual-species cultures. Microbial community analysis revealed the high relative abundance of Pseudoalteromonas piscicida during the initial days of exposure, demonstrating the dominant role of this bacterium in the biofilm structure.展开更多
基金financially supported by the National Natural Science Foundation of China(No.5161101078)CAS President’s International Fellowship Initiative(PIFI)(No.Y60708WP08)+1 种基金the Public welfare project of Zhejiang Province(No.2015C31031)the Natural Science Foundation of Ningbo,China(No.2015A610070)
文摘An exopolysaccharide substances produced by Vibrio neocaledonicus sp. was introduced as a novel green inhibitor against the corrosion of carbon steel in artificial seawater and acidic media. The produced extracellular polymeric substance（EPS） is heterogeneous with composition of polysaccharides, nucleic acids and protein and average molecular weight of 29,572 Da. Adsorption of EPS on the metal surfaces and formation of Fe-EPS complexes acted as a barrier to prevent the oxygen penetration and hindered anodic and cathodic reactions. The inhibitory effect increases with increasing EPS concentration and exposure time. The highest corrosion inhibitory effect（95.1%） was observed for 10 g/L of EPS after 5 days of exposure in seawater. This is the highest inhibitory effect ever been reported by EPSs. While, the optimum concentration of EPS with the highest inhibition efficiency in 1 N H;SO;was 1000 ppm. The influence of different parameters, such as initial pH, growth phase, various nitrogen and carbon sources on the production of EPS and its corrosion inhibitory effect were also investigated. According to results,the optimum culture medium for EPS production is contained artificial seawater including 5% mannitol as carbon source and 0.1%（NH;）;SO;as nitrogen source at pH = 8. This medium could produce 22.24 g/L EPS during 3 days’ incubation at 30 ℃. The corrosion inhibitory efficiency of obtained EPS was 95.97%.
基金financially supported by the National Natural Science Foundation of China(No.51871050)the Natural Science Foundation of Liaoning Province(No.20180510041)+1 种基金the Liaoning Revitalization Talents Program(No.XLYC1907158)the Fundamental Research Funds for the Central Universities of the Ministry of Education of China(N180205021 and N180203019)。
文摘Complex interactions within a microbial consortium can induce severe corrosion in oil pipelines.This study investigated the mechanism of microbiologically influenced corrosion(MIC)that led to failure of X52 steel pipelines after hydrostatic testing.Laboratory hydrostatic testing with untreated lake water and underground water were used to simulate and study the events that led to the actual corrosion.Biofilm analysis,weight loss,and several electrochemical measurements demonstrated rapid corrosion rates after hydrostatic testing.Analysis of microbial community structures revealed that methanogenic archaea and sulfate reducing bacteria(SRB),introduced by the hydrotest water,formed corrosive biofilms on X52 steel coupon surfaces that induced severe pitting.
基金supported by National Natural Science Foundation of China (No. 5161101078)Ningbo 135 Marine Economic Innovation and Development Demonstration Project (No. NBHY-2017-Z2)
文摘The effects of low electromagnetic field (EMF)(B = 2 mT) on the corrosion of pure copper in the absence and presence of multispecies marine aerobic bacteria were investigated in this work. The results showed that EMF has an inhibitory effect on copper metals and decreases the corrosion rate of copper metals in sterile artificial seawater. However, microbiologically influenced corrosion of Cu was increased in the presence of electromagnetic field due to its effect on the biofilm morphology and structure. EMF reduced the growth rate of bacteria and decreased bacterial attachment, thereby forming a heterogeneous and non-stable biofilm on the Cu surface in the presence of EMF. Moreover, the biofilm was dispersed throughout the surface after 7 days, whereas the scattered bacteria were observed on the surface after 10 days. Confocal laser scanning microscopy images showed large and deep pits on the surface in the presence of EMF and confirmed the acceleration of Cu corrosion in the presence of EMF and multispecies bacteria. Furthermore, XPS and FTIR results demonstrated that the corrosion products and metabolic by-products were significantly changed in the presence of EMF.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.N2002001)the National Natural Science Foreign Youth Foundation of China(No.52050410345)the Natural Science Foundation of Ningbo(No.2018A610211)。
文摘Multi-species biofilms are found in various bacterial habitats and have industrial relevance. These complex bacterial communities have synergetic effects, unlike a single species. Therefore, it is critical to evaluate these complex communities as a whole. Here, the inhibitory eff ect of single-and dual-species biofilms of Vibrio neocaledinocus sp. and Pseudoalteromonas piscicida for A36 carbon steel corrosion was investigated. The results demonstrated that the synergistic interactions of the monoculture increased the overall biomass production of the dual-species biofilm, but the growth rate was reduced in the presence of the dual-species culture due to a lack of nutrients. Field emission scanning electron microscopy images also confirmed the development of biofilms—they became more homogenized via exposure time in both the mono-and dual-species cultures. The corrosion resistance of A36 carbon steel positively increased because of the dual-species interactions. This reached the highest value after four weeks of exposure. The highest corrosion inhibition e fficiency of 99.8% was achieved in the dual-species cultures. Microbial community analysis revealed the high relative abundance of Pseudoalteromonas piscicida during the initial days of exposure, demonstrating the dominant role of this bacterium in the biofilm structure.
