微生物生物膜下的钢铁材料腐蚀研究进展

综述了近年来有关SRB引起的钢铁腐蚀研究进展,分析了SRB生物膜的形成机制,介绍了传统SRB腐蚀机理、生物催化硫酸盐还原阴极反应腐蚀机理,以及SRB诱导生物矿化作用形成的沉淀垢膜下的碳钢腐蚀研究现状,着重介绍了生物能量学和生物电化学在推动SRB导致的微生物腐蚀机理研究中的重要作用,并在此基础上介绍了目前最新的对生物膜下SRB的控制技术和方法,为SRB腐蚀及控制提供参考。     

静磁场下硫酸盐还原菌对HSn70-1铜合金的腐蚀行为

采用失重法、电化学测量和表面分析技术研究了有、无静磁场环境下,在含有硫酸盐还原菌(SRB)的培养基中HSn70-1铜合金的腐蚀行为。结果表明:SRB条件下,HSn70-1铜合金腐蚀质量损失最大,无磁场下的腐蚀电流密度远大于有磁场条件下的,磁场的加入可以有效地减缓HSn70-1铜合金的腐蚀。SEM,EDS,XRD和XPS实验分析表明,静磁场下HSn70-1铜合金表面腐蚀产物膜均匀致密,腐蚀产物为金属硫化物,Cu的化合价以一价(Cu+)为主;而无磁场时腐蚀产物疏松,腐蚀产物硫化物中Cu主要为二价(Cu2+)。静磁场条件下所形成的致密的Cu2S腐蚀产物层阻碍腐蚀的发生,有效地减缓了HSn70-1铜合金的腐蚀。     

Development of microbially influenced corrosion on carbon steel in a simulated water injection system

Microbially influenced corrosion (MIC) on internal pipeline surfaces has become a severe problem during the water injection process in secondary oil recovery. The formation of a biofilm, normally dominated by sulfate‐reducing bacteria (SRB), is believed to be the critical step of the MIC process. A continuously fed biofilm simulating the water injection process was operated to investigate the influence of biofilm development on MIC behavior in the early phase of corrosion development. The development of the corrosion product film and biofilm was monitored for 5 months with electrochemical impedance spectroscopy, linear polarization resistance, scanning electron microscopy, 3D optical profiling, and direct weight measurement. MIC development was found to comprise three phases: initialization, transition, and stabilization. The initialization phase involved the formation of the corrosion product layer and the initial attachment of the sessile microbes on metal surface. In the transition phase, the MIC process gradually shifted from charge‐transfer‐controlled reaction to diffusion‐controlled reaction. The stabilization phase featured mature and compact biofilm on the metal surface, and the general corrosion rate (CR) decreased due to the diffusional effect, while the pitting CR was enhanced at a lower carbon source level, which supported the mechanism of direct electron uptake from the metal surface by SRB.     

仿生超滑表面对Al基体微生物腐蚀防护性能与机制研究

采用电化学刻蚀-表面修饰-全氟聚醚油注入三步法在模板材料纯Al表面制备了仿猪笼草超滑表面,研究了仿生超滑表面对典型腐蚀微生物-硫酸盐还原菌的附着及所致腐蚀的影响.结果表明,仿生超滑表面在静态和动态环境均可明显抑制硫酸盐还原菌的附着,这主要是由于仿生超滑表面作为一种"类液体"表面,无法为细菌的附着提供锚点.同时,全氟聚醚油可通过阻止腐蚀性介质向基体的渗入,抑制基底Al的腐蚀过程.该研究的开展可为海洋微生物腐蚀防护材料的开发提供理论依据和模型.     

Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

Sulphate reducing bacteria are known to play a major role in anaerobic microbiological influenced corrosion of steels, but mechanisms behind their influence are still source of debates as certain phenomena remain unexplained. Some experiments have shown that hydrogen consumption by SRB or hydrogenase increased the corrosion rate of mild steel. This was observed only in the presence of phosphate species. Here the cathodic behaviour of phosphate species on steel was studied to elucidate the role of phosphate in anaerobic corrosion of steel. Results showed: a linear correlation between reduction waves in linear voltammetry and phosphate concentration at a constant pH value; that phosphate ions induced considerable anaerobic corrosion of mild steel, which was sensitive to hydrogen concentration in the solution; and that the corrosion potential of stainless steel in presence of phosphate was shifted to more negative values as molecular hydrogen was added to the atmosphere in the reaction vessel. Phosphate species, and possibly other weak acids present in biofilms, are suggested to play an important role in the anaerobic corrosion of steels via a reversible mechanism of electrochemical deprotonation that may be accelerated by hydrogen removal.     

脱硫弧菌引起的铝的微生物腐蚀机理研究

目的揭示培养周期内脱硫弧菌(一种硫酸盐还原菌)引起的铝的微生物腐蚀机理。方法采用细胞计数、荧光显微镜、电子显微镜、X射线能谱仪以及电化学测试等技术,测试并分析铝在硫酸盐还原菌(SRB)培养基中的腐蚀行为和机理。结果培养初期,SRB没有引起铝的腐蚀速率加速。铝电极的线性极化电阻在SRB培养基中的值甚至高于无菌培养基。这是因为生物膜的累积阻碍了基体与溶液介质界面的电子传输。随着培养时间的延长,铝在SRB培养基中的腐蚀速率明显提高。培养7天时,铝电极在SRB培养基中的腐蚀电流比无菌培养基中高3个数量级。结论随着时间的延长,培养基中有机碳源等营养成分消耗过多,导致SRB无法从培养基中获得足够的营养源,进而转向从铝中获取自身呼吸作用所需的能量。同时,由于生物膜的覆盖导致膜下微环境的改变,局部酸性可能较大,进而加速了点蚀的形成。     

Identification of steel corrosion associated with sulfate-reducing bacteria by electrochemical noise technique

Deterioration of steel structures in natural waters can result from microbiologically influenced corrosion (MIC) such as that caused by sulfate-reducing bacteria (SRB). Corrosion pits associated with MIC have been recently observed in submerged steel bridge piles and there is renewed interest to assess their deterioration. Conventional electrochemical techniques to identify MIC have been complicated due to the effects of the surface films and the mechanism for charge transfer by the bacteria on the steel surface. An electrochemical noise (EN) technique to identify steel corrosion in an aqueous solution has been developed and the method ideally can identify the onset of local pitting, but complications and limitations relating to data acquisition, filtering, and interpretation exist. EN analysis was shown to differentiate SRB and corrosion activity including initial biofilm development, pitting corrosion development, and diminution of SRB activity. Electrochemical behavior, environmental characteristics, SRB activity, and corrosion modality provided consistent correlation to EN and localized corrosion development.     

Microbiologically Induced Corrosion of X80 Pipeline Steel in a Near-Neutral pH Soil Solution

MIC of X80 pipeline steel in a near-neutral pH soil solution in the presence and absence of sulfate-reducing bacteria(SRB) was monitored by electrochemical techniques and microbiological tests. The results show that soil solution is more close to the complex soil environment around pipeline. The activity of SRB leads to the shift of the phase response to low frequency, the decrease of electrolyte resistance and the alteration of dielectric constant of the film. Both the activity and metabolite of SRB influence the corrosion behavior of the steel. The steel surface undergoes localized attack in the SRB-inoculated soil solution, whereas only slight uniform corrosion occurs in the sterile soil solution.     

The corrosion behavior of 70/30 copper‐zinc alloy under the biofilm of sulfate‐reducing bacteria

A laboratory study was carried out on the effect of the biofilm of sulfate‐reducing bacteria (SRB), which plays an important role in corrosion of 70/30 copper‐zinc alloy in culture media under anaerobic condition. The API medium was used to culture the SRB in Zhongyuan oilfield. Potential/time measurement showed that the presence of SRB makes the corrosion potential more active with SRB growth metabolite. Electrochemical impedance spectroscopy (EIS) was used to analyse the electrode process of 70/30 Cu‐Zn alloy with SRB biofilm. Scanning electron microscopy (SEM) examinations revealed the formation of biofilm and corrosion products during exposure to SRB‐containing culture medium. X‐ray diffraction and EDS were used to analyse the corrosion products. The results show that the variation of activity of the SRB biofilm changes with SRB growth by the linear polarization resistance (R_p) and the EIS in culture medium inoculated SRB.     

Surface chemistry and corrosion behaviour of 304 stainless steel in simulated seawater containing inorganic sulphide and sulphate-reducing bacteria

Although many studies have been carried out regarding the role of sulphide anions in promoting microbial corrosion of various metal substrates, very little is known about the differences between inorganic sulphide and biogenically-derived sulphide by sulphate-reducing bacteria (SRB) and what the reasons for differing corrosion behaviour between the two types of sulphide may be towards common metals. In this study, various electrochemical and surface analytical techniques were employed to study the effect of the inorganic and biogenic sulphide (active SRB present) on the surface chemistry and corrosion behaviour of 304 stainless steels in a simulated seawater-based modified Baar’s (SSMB) medium. Clear differences in the surface chemistry of the sulphurised passive film by inorganic and biogenic sulphide (active SRB present) were quantified by X-ray photoelectron spectroscopy (XPS). The transformation of metal sulphides in abiotic and biotic sulphide solutions with the exposure time was correlated with different corrosion behaviour of 304 stainless steels.     

Enhanced Bio-corrosion Resistance by Cu Alloying in a Micro-alloyed Pipeline Steel

On the composition base of commercial X65 grade pipeline steels, a Cu modified pipeline steel was designed to show improved resistance to microbially induced corrosion (MIC). The mechanical properties of the Cu-added steel and its corrosion behavior in a soil solution inoculated with sulfate-reducing bacteria (SRB) were investigated in this work. The results demonstrated that Cu-added steel exhibits a good combination of strength and toughness. Cu ions released from the Cu-added steel could effectively kill the SRB attaching on the steel surface, thus evidently decreased the pit depth and diameter of Cu-added steel. Furthermore, during the long-term immersion, the Cu-rich film formed by the enrichment of Cu in the corrosion product layer on the steel surface could also contribute to the improvement of the bio-corrosion resistance of Cu-added steel.     

The effect of cathodic polarization on the corrosion behavior of X65 steel in seawater containing sulfate-reducing bacteria

Sulfate-reducing bacteria (SRB) are one of the main reasons for the accelerated corrosion of steel. Cathodic polarization has been reported as an effective and economic method against marine corrosion, including microbiologically induced corrosion. However, the interaction between cathodic polarization and microbial activity has not been well defined. In this study, a fluorine-doped tin oxide electrode is used to study the effect of cathodic current on SRB cells. Fluorescence microscopy results clearly show that the attachment degree of SRB is dependent on the electric quantity and current intensity. The large electric quantity and high cathodic current (400 mA/m² × 30 h) can effectively inhibit bacterial attachment and subsequent biofilm formation. Furthermore, the effect of cathodic potential on the corrosion behavior of X65 steel in the presence of SRB is systematically investigated. Results show that the impressed charges, the increase of pH, and the formation of calcareous deposits on the electrode surface at the cathodic potential of −1,050 mV/SCE inhibit the attachment of SRB. In turn, the presence of SRB also interferes with the electrochemical reactions that occur during the polarization process, thus increasing the cathodic current. The interaction between SRB-induced corrosion and the process of preventing corrosion by various cathodic potentials is discussed.     

Determination of biocorrosion of low alloy steel by sulfate‐reducing Desulfotomaculum sp. isolated from crude oil field

In this study corrosion behavior of low alloy steel, in the presence of anaerobic sulfate‐reducing Desulfotomaculum sp. which was isolated from an oil production well, was investigated. In order to determine corrosion rates and mechanisms, mass loss measurements and electrochemical polarization studies were performed without and with bacteria in the culture medium. Scanning electron microscopic observations and energy dispersive X‐ray spectra (EDS) analysis were made on steel coupons. The effect of iron concentration on corrosion behavior was determined by Tafel extrapolation method. In a sterile culture medium, as the FeSO₄ · 7H₂O concentration increased, corrosion potential (E_cor) values shifted towards more anodic potentials and corrosion current density (I_cor) values increased considerably. After inoculation of sulfate‐reducing bacteria (SRB), E_cor shifted towards cathodic values. I_cor values increased with increasing incubation time for 10 and 100 mg/L concentrations of FeSO₄ · 7H₂O. Results have shown that the corrosion activity changed due to several factors such as bacterial metabolites, ferrous sulfide, hydrogen sulfide, iron phosphide, and cathodic depolarization effect.     

磁场对Q235钢微生物腐蚀行为的影响

采用腐蚀失重法、电化学测量技术和表面分析技术研究硫酸盐还原菌 (SRB) 在外加磁场下对Q235钢的腐蚀行为。结果表明,磁场条件下SRB对Q235钢的腐蚀作用较无磁场条件下减轻,其阻抗值先减小后增大,而无磁场条件下的阻抗值先增大后减小,说明磁场条件下试样表面的生物膜形成滞后。SEM的分析结果显示,磁场条件下Q235钢表面的生物膜均匀致密,并且紧密地黏附在金属表面。清除腐蚀产物后,无磁场条件下的基体表面呈现较多腐蚀孔和腐蚀裂缝,而有磁场条件下的基体表面则相对平整,说明磁场能有效地抑制SRB对Q235钢的腐蚀。     

Microbial corrosion of Ni–Cu alloys by Aeromonas eucrenophila bacterium

The corrosion behavior of Ni–Cu alloy in Nutrient Broth medium (peptone from meat 5.0 g, meat extract (N source) 3.0 g, and sodium chloride 6.0 g in 1 L) and in the presence of Aeromonas eucrenophila, isolated from water treatment system, has been studied using electrochemical techniques. Results showed that the polarization curves exhibiting a cathodic shift of the corrosion potential confirmed the increase in the corrosion rates. According to EIS data lower Q_CPE value for 5 h indicates surface inhomogeneity resulting from surface metal roughening, which is the likely cause of the enhanced dissolution of the metal also observed in SEM micrographs. In addition, the pH values of the medium did not change throughout the experiment; however, after immersion the pH value decreased to acidic value and caused corrosion.     

恶臭腐蚀性硫化物的微生物治理研究

从土壤中分离筛选一株化能自养型的脱氮硫杆菌(Thiobacillus denitrificans,简称TD),经培养活化后用于抑制老化油储油罐污水及油田废水中微生物腐蚀及脱除硫化物。结果表明:加入TD生物制剂后,污水中FeS的去除率可达42.85%;污水中无机硫化物的总量去除率可达91.05%。介质中的SRB取片时比空白介质低2～3个数量级,菌量小于103 cells/ml;试验介质中无黑色的FeS出现,介质中也未检测到游离的硫离子存在;此外,TD生物制剂加入后基体材料N80钢表面腐蚀产物膜较少,可以看到样品表面保留了原有的痕迹,而添加无机培养基的油田废水以及空白油田废水中试样表面腐蚀产物膜较厚,且去除腐蚀产物膜后有明显的点蚀痕迹。TD生物制剂的加入抑制了基体材料表面SRB生物膜的形成,消耗了SRB代谢产生的活性FeS和H2S,从而抑制了由SRB引起的微生物腐蚀和环境污染。     

Comparison of Biocorrosion due to Desulfovibrio desulfuricans and Desulfotomaculum nigrificans Bacteria

One observes several species of sulfate-reducing bacteria in nature. Presence of these species in a media may cause microbial influenced corrosion (MIC) of materials differently. To investigate this aspect of MIC, corrosion tests were performed on three types of stainless steels. The tests were done in modified Baar’s media inoculated separately by the two species of SRB namely Desulfovibrio desulfuricans (DD) and Desulfotomaculum nigrificans (DN). Electrochemical and immersion tests were performed to assess the extent of uniform and localized corrosion of these steels. Biofilms formed on the corroded samples were analyzed for estimating various components of its extracellular polymeric substances. Hydrogenase enzyme of these bacteria was tested to determine its nature and activity. Higher degree of corrosivity was observed in case of media inoculated with DD as compared to DN. More active nature of hydrogenase enzyme, its location in the periplasmic phase in DD and higher fraction of carbohydrate in biofilm formed due to DD have been suggested to be responsible for higher degree of corrosivity caused by them.     

Study of the electrochemical behaviour of 304 stainless steel in postgate medium in the presence and absence of desulfovibrio desulfuricans

A comparative study has been undertaken on the behaviour of AISI 304 steel in Postgate medium with and without the presence of Desulfovibrio desulfuricans subspecies desulfuricans bacteria (strain DSM 642). Electrochemical studies were carried out with open circuit potential measurements, linear polarization, electrochemical impedance spectroscopy (EIS) and scanning electronic microscopy (SEM). In Postgate medium without bacteria, and as expected in stainless steels, the formation is observed of a protective surface passive film on the AISI 304 steel. On measuring the corrosion potentials (E_corr), it is noted that the potential tends to rise with the immersion time, and in the impedance graphs an increase is observed in the charge transfer resistance and a higher phase angle with respect to the other systems tested. However, in Postgate medium with Desulfovibrio desulfuricans (strain DSM 642), the tendency of the corrosion potentials (E_corr) is not uniform, though the recorded values are less noble than those for the medium without bacteria. A variation is observed in the properties of the layer of corrosion products in the presence of bacteria as the immersion time advances (due to the effects caused by the formation of corrosion products which gives rise to changes in the corrosion speed).     

Microbiologically Influenced Corrosion of Q235 Carbon Steel by Aerobic Thermoacidophilic Archaeon Metallosphaera cuprina

The effect of thermoacidophilic archaeon Metallosphaera cuprina (M. cuprina) on the corrosion of Q235 carbon steel in its culture medium was investigated in this work. In the sterile culture medium, the carbon steels showed uniform corrosion morphologies and almost no corrosion products covered the sample surface during 14 days of immersion test. In the presence of M. cuprina, some corrosion pits appeared on the surface of carbon steels in the immersion test, exhibiting typical localized corrosion morphologies. Moreover, the sample surfaces were covered by a large number of insoluble precipitates during the immersion. After 14 days, the thickness of precipitates reached approximately 50 μm. The results of weight loss test and electrochemical test demonstrated that the carbon steels in the M. cuprina-inoculated culture medium had higher corrosion rate than that in the sterile culture medium. The oxygen concentration cell caused by M. cuprina biofilms resulted in localized corrosion behavior, and the ferrous oxidation ability of M. cuprina accelerated the anodic dissolution of carbon steels, thus promoting the corrosion process of carbon steels.     

硫酸盐还原菌引起的微生物腐蚀的研究进展

简述了由硫酸盐还原菌（SRB）引起的微生物腐蚀（MIC）的机理，环境因素与SRB的协同效应对MIC的影响及控制SRB的措施的研究进展。