A method for detecting and evaluating microbial corrosion ability

Abstract

The present invention provides a method for detecting and evaluating the corrosion potential of microorganisms. The method uses a galvanic cell comprising a reference electrode and a detection electrode as an evaluation device. The evaluation method comprises the following steps: placing the detection electrode in an electrolyte solution containing a microbial fluid to obtain a time-potential relationship; and evaluating the first corrosion potential of the microorganism based on the time-potential relationship. The detection electrode is coated with a metal material. This evaluation method enables rapid and simple detection of the corrosion potential of microorganisms.

Description

Technical Field

[0001] The present invention belongs to the field of microbial corrosion, and in particular relates to a method for detecting and evaluating microbial corrosion ability. Background Art

[0002] Microorganisms are widely present in industrial environments, including oil and gas facilities, marine infrastructure, and municipal pipelines. Their metabolic activities can cause corrosion to metal materials, a process known as microbial corrosion (MIC). MIC is a major cause of pipeline degradation, resulting in significant equipment losses each year.

[0003] At present, electrochemical noise technology (EN) is mostly used to monitor corrosion caused by microorganisms online. The microbial corrosion ability is evaluated by obtaining electrochemical noise signals. However, the current electrochemical noise signal involves a complex analysis and calculation process, which cannot quickly and easily realize the monitoring of microbial corrosion.

[0004] Therefore, how to provide a simple and rapid method for evaluating the corrosion capacity of microorganisms is a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0005] The present invention provides a method for detecting and evaluating the corrosion ability of microorganisms, which can realize rapid and convenient detection of the corrosion ability of microorganisms.

[0006] In one aspect of the present invention, a method for detecting and evaluating the corrosion capacity of microorganisms is provided, wherein a galvanic cell including a reference electrode and a detection electrode is used as an evaluation device. The evaluation method comprises the following steps:

[0007] placing the detection electrode in an electrolyte solution containing a microbial fluid to obtain a time-potential relationship;

[0008] evaluating a first corrosion ability of the microorganism according to the time-potential relationship;

[0009] Wherein, the surface of the detection electrode is coated with metal material.

[0010] According to one embodiment of the present invention, the method further includes: placing the detection electrode in an electrolyte solution containing microorganisms to obtain a time-metal content relationship of the detection electrode; and evaluating the second corrosion ability of the microorganisms based on the time-metal content relationship.

[0011] According to one embodiment of the present invention, the primary cell includes a first chamber and a second chamber separated by a proton exchange membrane, the detection electrode and the electrolyte solution containing the microbial fluid are located in the first chamber, and the reference electrode and the electrolyte solution are located in the second chamber.

[0012] According to one embodiment of the present invention, the metal material includes at least one of iron, magnesium, zinc, aluminum, and titanium.

[0013] According to one embodiment of the present invention, the detection electrode includes a graphite electrode layer and a metal material layer located on a surface of the graphite electrode layer.

[0014] According to one embodiment of the present invention, the reference electrode includes a graphite electrode layer.

[0015] According to one embodiment of the present invention, the electrolyte solution further contains a carbon source, and the carbon source includes at least one of sodium lactate and sodium citrate.

[0016] According to one embodiment of the present invention, the volume content of the microbial liquid in the electrolyte solution is 1 to 10%; the mass content of the carbon source in the electrolyte solution is 1 to 10%.

[0017] According to one embodiment of the present invention, the microbial liquid is obtained by a method comprising the following steps:

[0018] After the microorganisms were cultured to the logarithmic growth phase, 10 3 ~10 7 cfu / mL of microbial solution, wherein the culture temperature is 35-38°C and the culture time is 3-4 days.

[0019] According to one embodiment of the present invention, the electrolyte solution comprises, in terms of mass-volume concentration:

[0020] Magnesium sulfate 2.0g / L, calcium sulfate 1.0g / L, ammonium chloride 1.0g / L, dipotassium hydrogen phosphate 0.5g / L, yeast powder 0.02g / L, ferrous ammonium sulfate 1.0g / L, sodium lactate 0.07g / L, sodium citrate 0.1g / L.

[0021] According to one embodiment of the present invention, the microorganisms include at least one of sulfate reducing bacteria, saprophytic bacteria, and Pseudomonas aeruginosa; wherein the Pseudomonas aeruginosa is ATCC9027.

[0022] The implementation of the present invention has at least the following beneficial effects:

[0023] The present invention provides a method for detecting and evaluating the microbial corrosion potential. This method utilizes a galvanic cell consisting of a reference electrode and a detection electrode as an evaluation device to obtain a time-potential relationship diagram of the interaction between the detection electrode and the microorganism at different times, thereby evaluating the primary corrosion potential of the microorganism. This electrochemical evaluation method utilizes electrical signals and, while minimizing the impact on microbial properties, objectively and accurately captures the changing patterns of microbial corrosion. This method is characterized by its simplicity and rapidity. Furthermore, the evaluation method provided by the present invention is capable of detecting and evaluating a variety of microorganisms. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of an evaluation device according to one embodiment of the present invention;

[0025] Figure 2 1 is a time-potential relationship diagram of Example 1 of the present invention and Comparative Example 1;

[0026] Figure 3 1 is a scanning electron microscope energy dispersive spectroscopy (SEM-EDS) image of the entire surface of the detection electrode of the blank group of the present invention, comparative example 1 and example 2;

[0027] Figure 4 is a focused ion beam scanning electron microscope (FIB-SEM) image of the cross section of the detection electrode of Comparative Example 1 and Example 2 of the present invention;

[0028] Figure 5 is a time-potential relationship diagram of Example 3 of the present invention;

[0029] Figure 6 is a SEM-EDS image of Example 4 of the present invention;

[0030] Figure 7 is a pitting depth diagram of Comparative Example 2 of the present invention;

[0031] Figure 8 is a pitting depth distribution diagram of Comparative Example 2 of the present invention;

[0032] Figure 9 3 is a pitting width distribution diagram of Comparative Example 2 of the present invention.

[0033] Description of reference numerals:

[0034] 1-first chamber; 2-second chamber; 3-wire; 4-proton exchange membrane; 102-reference electrode; 101-detection electrode. DETAILED DESCRIPTION

[0035] The specific embodiments listed below are merely illustrative of the principles and features of the present invention. The examples are intended only to explain the present invention and are not intended to limit the scope of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0036] The present invention provides a method for detecting and evaluating the corrosion capacity of microorganisms, using a primary cell comprising a reference electrode and a detection electrode as an evaluation device. The evaluation method comprises the following steps: placing the detection electrode in an electrolyte solution containing a microbial fluid to obtain a time-potential relationship; and evaluating the first corrosion capacity of the microorganism based on the time-potential relationship; wherein the surface of the detection electrode is coated with a metal material.

[0037] In the present invention, the primary cell is a device that converts chemical energy into electrical energy and is based on the redox reaction occurring at the contact interface between the electrode and the electrolyte solution.

[0038] The galvanic cell evaluation device comprises at least a reference electrode and a detection electrode, wherein the reference electrode and the detection electrode are arranged opposite to each other and connected by a wire.

[0039] The reference electrode and the detection electrode are located in the same chamber, or the reference electrode and the detection electrode are located in different chambers. When the reference electrode and the detection electrode are located in the same chamber, the reference electrode and the detection electrode are separated by a proton exchange unit, so that the detection electrode is located in a first electrolyte solution and the reference electrode is located in a second electrolyte solution. When the reference electrode and the detection electrode are located in different chambers, the detection electrode is located in the first electrolyte solution in one chamber, and the reference electrode is located in the second electrolyte solution in the other chamber, and the first electrolyte solution and the second electrolyte solution are connected through the proton exchange unit. The first electrolyte solution and the second electrolyte solution can be the same or different.

[0040] In the present invention, at least the detection electrode is located in an electrolyte solution containing microbial fluid, which contains both the microbial fluid and nutrients required for microbial metabolic activities and can also transfer ions.

[0041] The surface of the detection electrode is coated with a metal material. By measuring the potential change curve when the detection electrode interacts with the microorganism for different periods of time, a time-potential relationship can be obtained. This time-potential relationship is a graph with the interaction time between the detection electrode and the microorganism as the horizontal axis and the potential of the detection electrode as the vertical axis.

[0042] The primary corrosion potential of microorganisms is evaluated based on this time-potential relationship. This primary corrosion potential includes a qualitative analysis of the microorganisms. Specifically, when the potential of the detection electrode drops sharply, then gradually rises and levels off, the time-potential relationship exhibits a "U"-shaped trend, indicating that the presence of microorganisms is causing corrosion of the metal material.

[0043] The inventors' research suggests that when the detection electrode is located in an electrolyte solution containing microbial fluid, the metal material comes into contact with the microorganisms. At this point, the detection electrode acts as the negative electrode, causing the metal material to lose electrons, resulting in an oxidation reaction. The reference electrode acts as the positive electrode, causing hydrogen ions near the reference electrode to gain electrons, resulting in a reduction reaction. The oxidation reaction near the detection electrode accumulates negative charge on the detection electrode surface, causing the potential to drop. As the redox reaction proceeds, electrons are transferred, the metal material is gradually consumed, and the potential levels off, reaching an equilibrium state.

[0044] The present invention does not impose any restrictions on the raw materials of the detection electrode and the reference electrode, as long as an oxidation reaction can occur near the detection electrode and a reduction reaction can occur near the reference electrode. For example, the raw materials of the detection electrode may contain only metal, or the raw materials of the detection electrode may be composed of metal and other conductive materials (non-metals, oxides, etc.), while the raw materials of the reference electrode may contain only other conductive materials (non-metals, oxides, etc.).

[0045] The present invention does not limit the method for coating the metal material on the detection electrode; conventional physical deposition methods in the art may be employed. For example, magnetron sputtering is employed. Specifically, the method includes first polishing the surface of the electrode to be coated with 1500-grit sandpaper to remove surface grease. The metal material to be deposited is positioned opposite the polished electrode, evacuated to a high vacuum, and a high voltage is applied to deposit the metal material onto the surface of the electrode to be coated, forming a film. This results in a detection electrode coated with the metal material.

[0046] The present invention does not limit the types of microorganisms, and the type is determined according to the actual microorganisms to be detected, thereby achieving detection and evaluation of different microorganisms.

[0047] Through the above steps, it was discovered that the method for evaluating the microbial corrosion potential provided by the present invention utilizes a galvanic cell composed of a reference electrode and a detection electrode as an evaluation device, obtaining a time-potential relationship diagram for the interaction between the detection electrode and the microorganism at different times, thereby evaluating the primary corrosion potential of the microorganism. This electrochemical evaluation method can objectively and accurately determine the changing patterns of microbial corrosion using electrical signals while minimizing the impact on microbial properties. This method is characterized by its simplicity and rapidity. Furthermore, the evaluation method provided by the present invention is capable of detecting and evaluating different microorganisms.

[0048] To further quantitatively analyze the microbial corrosion potential, the present invention further includes: placing a detection electrode in an electrolyte solution containing microorganisms to obtain a time-metal content relationship at the detection electrode; and evaluating a second microbial corrosion potential based on the time-metal content relationship. This second corrosion potential includes a quantitative analysis of the microbial corrosion potential.

[0049] Among them, the time-metal content relationship refers to the change in the content of metal atoms in the metal material with contact time after the metal material comes into contact with microorganisms.

[0050] After research, the inventors believe that when metal materials come into contact with microorganisms, an oxidation reaction occurs, resulting in the continuous consumption of the metal materials. By measuring the content of metal atoms in the metal materials and using the amount of consumed metal to quantitatively analyze the microbial corrosion ability, an objective and accurate evaluation of the microbial corrosion ability can be achieved.

[0051] Furthermore, the present invention can detect and evaluate the corrosion potential of different microorganisms. Specifically, the following steps are involved: placing detection electrodes in electrolyte solutions of different microbial fluids to obtain the corresponding time-potential relationships for each microorganism; and evaluating the third corrosion potential of the microorganism based on the corresponding time-potential relationships. This third corrosion potential includes a comparison of the corrosion rate and corrosion duration of different microorganisms.

[0052] In order to avoid mutual influence between the reactions occurring near the reference electrode and the detection electrode, the present invention uses a separation unit to separate the reference electrode and the detection electrode from each other. In one embodiment of the present invention, the primary cell includes a first chamber and a second chamber separated by a proton exchange membrane. The first chamber contains an electrolyte solution containing a microbial liquid, and the detection electrode is located in the electrolyte solution containing the microbial liquid. The second chamber contains an electrolyte solution, and the reference electrode is located in the electrolyte solution. It should be noted that the electrolyte solution in which the reference electrode is located does not contain microbial liquid.

[0053] The present invention is not limited to metal materials, including but not limited to at least one of iron, magnesium, zinc, aluminum, and titanium.

[0054] By limiting the raw materials of the detection electrode and reference electrode, a stable time-potential relationship can be achieved, which facilitates the objectivity and accuracy of the evaluation method. In one embodiment of the present invention, the detection electrode comprises a graphite electrode layer and a metal material layer located on the surface of the graphite electrode layer, i.e., the metal material layer is deposited on the surface of the graphite electrode layer. The reference electrode comprises a graphite electrode layer. The graphite electrode layer refers to an electrode layer made of graphite.

[0055] In order to enable the electrolyte solution to provide the microorganisms with nutrients required for metabolic activities, the electrolyte solution also contains a carbon source, which includes at least one of sodium lactate and sodium citrate.

[0056] In the present invention, the mass content of the carbon source in the electrolyte solution is 1 to 10%.

[0057] In the electrolyte solution containing microbial fluid, the volume content of the microbial fluid in the electrolyte solution is 1-10%. For example, by mixing 3 mL of microbial fluid with 97 mL of the initial electrolyte solution, an electrolyte solution containing microbial fluid with a volume content of 3% can be obtained.

[0058] The microbial liquid is obtained by a method comprising the following steps: culturing the microorganisms to a logarithmic growth phase, and then preparing 10 3 ~10 7 cfu / mL of microbial solution, wherein the culture temperature is 35-38°C and the culture time is 3-4 days.

[0059] In order to enable the electrolyte solution to play the role of transferring ions, the electrolyte solution also includes the following according to mass-volume concentration: magnesium sulfate 2.0 g / L, calcium sulfate 1.0 g / L, ammonium chloride 1.0 g / L, dipotassium hydrogen phosphate 0.5 g / L, yeast powder 0.02 g / L, sodium lactate 0.07 g / L, and sodium citrate 0.1 g / L.

[0060] The present invention is not limited to the type of microorganisms, such as bacteria. In one embodiment of the present invention, the microorganisms include at least one of sulfate-reducing bacteria, saprophytic bacteria, and Pseudomonas aeruginosa. Pseudomonas aeruginosa is ATCC 9027.

[0061] The present invention is further described below by way of specific examples and comparative examples. Unless otherwise specified, the reagents, materials, and instruments used below are all conventional reagents, materials, and instruments, all of which are commercially available, and the reagents and materials involved can also be synthesized by conventional synthesis methods.

[0062] use Figure 1The evaluation device shown includes a first chamber 1 and a second chamber 2 (each chamber has an effective volume of 150 mL), the two chambers are separated by a proton exchange membrane 4, the first chamber contains a first electrolyte solution, the second chamber contains a second electrolyte solution, the detection electrode 101 is located in the first electrolyte solution, and the reference electrode 102 is located in the second electrolyte solution. The detection electrode 101 and the reference electrode 102 are connected by a wire 3;

[0063] The detection electrode includes a 10mm×10mm×3mm high-purity graphite sheet and iron (Fe) on the surface of the graphite sheet. The SEM and FIB analysis results of the detection electrode (blank group G-Fe) are shown in Figure 3 , EDS element analysis is shown in Table 1; the reference electrode is a 10mm×10mm×3mm high-purity graphite sheet;

[0064] The initial electrolyte solution includes, by mass-volume concentration, 0.07 g / L sodium lactate, 2.0 g / L magnesium sulfate, 1.0 g / L calcium sulfate, 1.0 g / L ammonium chloride, 0.5 g / L dipotassium hydrogen phosphate, 0.1 g / L sodium citrate, and 0.02 g / L yeast extract. The initial electrolyte solution is autoclaved at 121°C for 20 min, and nitrogen gas is introduced for 1 h after autoclaving to remove dissolved oxygen from the solution.

[0065] The first electrolyte solution includes 3 mL of microbial liquid and 97 mL of initial electrolyte solution; the second electrolyte solution includes 100 mL of initial electrolyte solution, wherein the preparation process of the microbial liquid includes: culturing the microorganisms to the logarithmic growth phase, preparing 10 7 cfu / mL of microbial liquid, the culture temperature is 38°C, and the culture time is 3 days; the microorganisms are selected from sulfate reducing bacteria (SRB), total general bacteria (TGB), and Pseudomonas aeruginosa (Pa), among which sulfate reducing bacteria and saprophytic bacteria are obtained by culturing produced water on-site in the oil field.

[0066] Example 1

[0067] In this example, sulfate reducing bacteria (SRB) was used to prepare the microbial solution. Figure 1 The electrochemical test was performed using the device shown in the figure and a CHI660E electrochemical workstation (Shanghai Chenhua Instrument Co., Ltd., China). The first chamber was set to an aerobic environment, and the time-potential relationship (G-Fe / bacteria) was obtained, as shown in FIG. Figure 2 shown.

[0068] Example 2

[0069] After 7 days of electrochemical testing in Example 1, the detection electrode was taken out, and the surface of the detection electrode was rinsed with anhydrous ethanol to remove surface impurities. After natural air drying in an environment filled with N2, it was stored in a vacuum drying oven and directly subjected to SEM-EDS and FIB-SEM tests. The results are shown in FIG. Figure 3 and Figure 4 The content of metal atoms on the electrode before and after the electrochemical test after 7 days was detected by EDS analysis. The results are shown in Table 1.

[0070] Example 3

[0071] In this example, sulfate reducing bacteria (SRB), total general bacteria (TGB), and Pseudomonas aeruginosa (Pa) were used to prepare SRB liquid, TGB liquid, and Pa liquid, respectively. SRB and TGB were from the WH# oil field, and the second-generation Pseudomonas aeruginosa Pa was the standard strain ATCC9027. Pa was aerobically cultured using 2216E medium (37.4 g / L), which contained 5.0 g / L peptone, 1.0 g / L yeast extract, 0.1 g / L ferric citrate, and 19. 45g / L sodium chloride, 5.98g / L magnesium chloride, 3.24g / L sodium sulfate, 1.8g / L calcium chloride, 0.55g / L potassium chloride, 0.16g / L sodium carbonate, 0.08g / L potassium bromide, 0.034g / L strontium chloride, 0.022g / L boric acid, 0.004g / L sodium silicate, 0.0024g / L sodium fluoride, 0.0016g / L ammonium nitrate, and 0.008g / L disodium hydrogen phosphate.

[0072] use Figure 1 The evaluation device obtains the time-potential relationship of three kinds of bacteria, which are recorded as SRB-WH#, TGB-WH#, and Pa-aerobic, respectively. Figure 5 shown.

[0073] Example 4

[0074] After 4 days of electrochemical testing in Example 3, the detection electrode was taken out, and the surface of the detection electrode was rinsed with anhydrous ethanol to remove surface impurities. After natural air drying in an environment filled with N2, it was stored in a vacuum drying oven and directly subjected to SEM-EDS testing. The results are shown in FIG. Figure 6 The content of metal atoms on the electrode before and after 4 days of electrochemical testing was detected by EDS analysis. The results are shown in Table 2.

[0075] Comparative Example 1

[0076] The method is basically the same as that in Example 1, except that "the first electrolyte solution includes 3 mL of microbial solution and 97 mL of initial electrolyte solution" is replaced by "the first electrolyte solution includes 100 mL of initial electrolyte solution", and "the first chamber is an aerobic environment" is replaced by "the first chamber is an anaerobic environment", and the time-potential relationship (G-Fe / sterile) is obtained, as shown in FIG. Figure 2 shown.

[0077] Comparative Example 2

[0078] The pitting corrosion test was conducted using a 30×10×5mm L245 coupon as a specimen. The specific operations included:

[0079] All exposed surfaces of the specimens were sanded with 400, 800, and 1200 grit sandpaper and then polished. They were rinsed with deionized water and ethanol and dried in air. Before testing, the specimens were exposed to ultraviolet light for 30 minutes. Afterwards, the specimens were immersed in an incubator containing three different microbial solutions and cultured at a constant temperature of 38°C for 7 days before use. Then, a rust removal solution was used to remove the biofilm and corrosion products on the surface of the specimens. The rust removal solution on the surface of the specimens was rinsed with deionized water. After drying, the depth and width of the pits on the surface of each specimen were observed using CLSM (LSM 710, Zeiss, Germany). Figure 7 、 Figure 8 、 Figure 9 The rust removal solution includes 500 mL of concentrated hydrochloric acid, 500 mL of deionized water, 3.5 g of hexamethylenetetraammonium, and the three different microbial solutions include SRB, TGB, and Pa.

[0080] Table 1

[0081]

[0082] Table 2

[0083]

[0084] according to Figure 2 It can be seen that under the condition of SRB, the potential of the detection electrode will drop sharply to about -0.8V, and then the potential will rise again until it tends to be flat. The inventor believes that SRB consumes Fe on the detection electrode, making the iron-graphite double layer on the detection electrode surface unstable and the potential changing. At this time, the following reaction occurs at the detection electrode: 4Fe → 4Fe 2+ +8e - In the first chamber, the carbon source undergoes the following reaction: 2CH3CHOHCOO - +2H2O→2CH3COO - +2CO2+8H + +8e- , SO4 occurs in the SRB cytoplasm 2- Reduction of: SO4 2- +9H + +8e - →HS - +4H2O (this reaction takes place inside the SRB cells, and electron transfer also takes place inside the SRB cells). The negative charge accumulates on the surface of the detection electrode, causing the potential to drop. Then, as organic matter is adsorbed on the electrode surface, a biofilm is formed after SRB is adsorbed on the electrode surface, and the metabolite HS - with Fe 2+ FeS corrosion products generated by the reaction. The biofilm and corrosion product layer are not fully formed. The corrosion product FeS is a conductive substance in the solution, which enhances the transfer of electrons and accelerates the consumption of Fe. As Fe is consumed, the potential rise tends to be flat.

[0085] According to Table 1, after the electrochemical test, the atomic percentage of Fe on the detection electrode is only 0.26%, indicating that Fe is completely consumed by SRB.

[0086] Figure 3 It is the SEM-EDS figure of blank group, comparative example 1 and embodiment 2, according to Figure 3 It can be seen that there are loose gaps on the surface of the detection electrode (blank group G-Fe) that has not been electrochemically tested. Example 1 carried out electrochemical testing under aerobic and bacterial conditions. After 7 days of testing, there was basically no Fe on the surface of the sample. EDS analysis showed that the atomic percentage of Fe was only 0.26%, and the Fe on the surface of the detection electrode was completely consumed by SRB. Therefore, under aerobic conditions, SRB will cause severe corrosion of metal materials. Comparative Example 1 carried out electrochemical testing under sterile and anaerobic conditions. Fe was still evenly distributed on the surface of the detection electrode (G-Fe-sterile). The EDS analysis in Table 2 showed that the atomic percentage of Fe was 9.17%, indicating that under sterile and anaerobic conditions, the Fe on the surface of the detection electrode was basically not consumed and Fe would not be severely corroded.

[0087] Figure 4 This is a focused ion beam scanning electron microscope (FIB-SEM) of Example 1 and Example 2, wherein Pt is a protective film plated to protect the Fe plated by magnetron sputtering from being bombarded. Figure 4 It can be seen that under sterile conditions, the Fe plated on the surface of the detection electrode is not consumed, as shown in Figure 4The FIB results are consistent with those in Figure 2. A silver-gray substance is visible beneath the Pt protective film, indicating that iron has not been consumed. Mapping analysis confirmed that this substance is elemental Fe. Under sterile conditions, a roughly 200nm Fe film is visible on the detection electrode. Under sterile conditions, as shown by the FIB-SEM results, no Fe film is present at the incision, and no Fe is detected in the mapping. This suggests that in the absence of an organic carbon source, SRB can utilize Fe as an electron donor to obtain energy to sustain their activities, causing corrosion of the metal.

[0088] according to Figure 5 As can be seen, in the presence of SRB, the detection electrode begins to consume Fe at 50,000 s, leading to a sharp drop in potential, which remains at around -0.6 V for 1.5 hours before rising sharply again. In the presence of TGB, the detection electrode begins to consume Fe at 76,000 s, with the potential dropping to around -0.6 V and remaining there for 5 hours. In the presence of Pa, the potential drop does not occur until 150,000 s, and remains at around -0.6 V for 28 hours before rising. This indicates that Fe consumption begins earliest and most rapidly in the presence of SRB, while Fe consumption begins latest and is slowest in the presence of Pa.

[0089] according to Figure 6 As shown in Table 2, after 20 hours of reaction in the presence of SRB, there was essentially no Fe on the electrode surface. EDS results showed an Fe atomic percentage of 0.08%. After 40 hours of reaction in the presence of TGB, the Fe atomic percentage was 0.48%. After 92 hours of reaction in the presence of Pa-aerobic, the Fe atomic percentage was 0.60%. This shows that SRB, TGB, and Pa can all corrode metallic Fe. The speed and duration of the corrosion reaction indicate the ability of bacteria to corrode metals: SRB > TGB > Pa.

[0090] according to Figure 7 、 8 9 shows that the L245 coupon will cause deeper pitting corrosion in SRB than in TGB. After immersion in SRB culture medium for 7 days, the maximum pitting depth of the L245 coupon is 10.3μm, while after immersion in TGB culture medium for 7 days, the maximum pitting depth is 8.2μm. It can be seen that SRB will cause more serious microbial corrosion than TGB. After immersion in Pa-aerobic environment for 7 days, the maximum pitting depth is only 3.5μm, and Pa causes the least corrosion to the metal. According to Figure 8The distribution of pitting can be seen in the figure. After the L245 coupon was immersed in the culture medium of SRB for 7 days, the pitting was concentrated in the range of 6-10 μm in depth and 5-20 μm in width. After being immersed in the culture medium containing TGB for 7 days, the pitting was concentrated in the range of 4-8 μm in depth and 6-22 μm in width. After being immersed in the Pa-aerobic environment for 7 days, the pitting was concentrated in the range of 1-3.5 μm in depth and 4-10 μm in width. WH# SRB has the strongest corrosion ability to carbon steel, followed by WH# TGB, and Pa has the weakest corrosion ability to carbon steel. Therefore, the corrosion ability of different bacteria obtained by analyzing the depth and width of pitting is consistent with the detection results of the detection electrode, indicating the accuracy of the evaluation method provided by the present invention. In addition, the evaluation method provided by the present invention is simpler and faster than the method of Comparative Example 2.

[0091] The above describes in detail the preferred embodiments of the present invention and their experimental verification. It should be understood that numerous modifications and variations based on the concepts of the present invention can be made by those skilled in the art without inventive effort. Therefore, any technical solution that can be derived by those skilled in the art based on the concepts of the present invention through logical analysis, reasoning, or limited experimentation based on the existing technology should be within the scope of protection defined by the claims.

Claims

1. A method for detecting and evaluating microbial corrosion ability, characterized in that: A primary cell comprising a reference electrode and a detection electrode is used as an evaluation device, and the evaluation method comprises the following steps: placing the detection electrode in an electrolyte solution containing a microbial fluid to obtain a time-potential relationship; evaluating a first corrosion ability of the microorganism according to the time-potential relationship, wherein the first corrosion ability includes a qualitative analysis of the corrosion ability of the microorganism; Wherein, the surface of the detection electrode is coated with a metal material; Also includes: placing the detection electrode in an electrolyte solution containing microorganisms, and obtaining a time-metal content relationship of the detection electrode; According to the time-metal content relationship, a second corrosion ability of the microorganism is evaluated, where the second corrosion ability includes a quantitative analysis of the corrosion ability of the microorganism.

2. The detection and evaluation method according to claim 1, characterized in that: The primary cell includes a first chamber and a second chamber separated by a proton exchange membrane. The detection electrode and the electrolyte solution containing the microbial fluid are located in the first chamber, and the reference electrode and the electrolyte solution are located in the second chamber.

3. The detection and evaluation method according to claim 1 or 2, characterized in that: The metal material includes at least one of iron, magnesium, zinc, aluminum and titanium.

4. The evaluation method according to claim 1 or 2, characterized in that The detection electrode includes a graphite electrode layer and a metal material layer located on the surface of the graphite electrode layer; and / or, The reference electrode includes a graphite electrode layer.

5. The detection and evaluation method according to claim 1 or 2, characterized in that: The electrolyte solution further contains a carbon source, and the carbon source includes at least one of sodium lactate and sodium citrate.

6. The detection and evaluation method according to claim 5, characterized in that: The volume content of the microbial liquid in the electrolyte solution is 1-10%; the mass content of the carbon source in the electrolyte solution is 1-10%.

7. The detection and evaluation method according to claim 6, characterized in that: The microbial liquid is obtained by a method comprising the following steps: After the microorganisms were cultured to the logarithmic growth phase, 10 3 ~10 7 cfu / mL of microbial liquid, wherein the culture temperature is 35-38°C and the culture time is 3-4 days.

8. The detection and evaluation method according to claim 7, characterized in that: The electrolyte solution comprises, in terms of mass-volume concentration: Magnesium sulfate 2.0g / L, calcium sulfate 1.0g / L, ammonium chloride 1.0g / L, dipotassium hydrogen phosphate 0.5g / L, yeast powder 0.02g / L, ferrous ammonium sulfate 1.0g / L, sodium lactate 0.07g / L, sodium citrate 0.1g / L.

9. The detection and evaluation method according to claim 6 or 7, characterized in that: The microorganisms include at least one of sulfate reducing bacteria, saprophytic bacteria, and Pseudomonas aeruginosa; Wherein, the Pseudomonas aeruginosa is ATCC 9027.

Images