Microorganism / polymetallic sulfide composite material as well as preparation method and application thereof

Abstract

The invention relates to a microorganism / polymetallic sulfide composite material as well as a preparation method and application thereof, and belongs to the technical field of crossing of environmental microorganisms and nano functional materials. The preparation method of the microorganism / polymetallic sulfide composite material comprises the following steps: (1) inoculating shewanella into an LB culture medium, and performing shake cultivation to obtain a bacterial solution; (2) centrifuging the bacterial liquid, adding precipitated bacterial sludge into an anaerobic reaction buffer solution, and then adding a water-soluble ferric iron salt solution, a water-soluble cobalt source salt solution and a water-soluble sulfur source salt solution; and carrying out shake cultivation to obtain the microorganism / polymetallic sulfide composite material. Through in-situ generation of the iron-cobalt-sulfur composite material on the surface of shewanella, stable loading and biological drive generation of nanoparticles are realized, so that the electron transfer rate and the system dechlorination efficiency are improved, the reaction life of the material is prolonged, and an efficient and sustainable pollutant removal effect is achieved.

Description

Technical Field

[0001] This application relates to the interdisciplinary field of environmental microbiology and nanomaterials, and in particular to a microbial / polymetallic sulfide composite material, its preparation method, and its application. Background Technology

[0002] With the rapid development of industries such as chemicals, pharmaceuticals, and pesticides, large quantities of halogenated hydrocarbons (such as carbon tetrachloride, chloroform, and trichloroethylene) have entered the environment. These compounds are persistent, bioaccumulative, and highly carcinogenic, making them difficult to completely remove using conventional physicochemical methods. Traditional chemical reduction or adsorption technologies suffer from high costs, severe secondary pollution, and low reaction rates.

[0003] Currently, the treatment of halogenated organic pollutants mainly includes nanomaterial catalytic reduction and microbial dehalogenation. Although the former has the advantage of fast reaction rate, the nanomaterials are prone to aggregation, have poor stability, and are consumed quickly, which limits their long-term application. The latter has the advantages of mild conditions and environmental friendliness, but its treatment effect is weak due to low electron transfer rate and limited metabolic efficiency. Summary of the Invention

[0004] In view of this, this application provides a microbial / multimetallic sulfide composite material, its preparation method and application. By generating iron-cobalt-sulfur composite material in situ on the surface of Shewanella, stable loading and bio-driven generation of nanoparticles are achieved, thereby improving the electron transfer rate and dechlorination efficiency of the system, extending the material reaction life, and achieving efficient and sustainable pollutant removal. This can effectively overcome the problems of easy agglomeration of nanomaterials, rapid decay of reactivity and low dehalogenation efficiency of microorganisms in the prior art.

[0005] The first aspect of this application provides a method for preparing a microbial / polymetallic sulfide composite material, comprising the following steps:

[0006] (1) Inoculate Shewanella into LB medium and culture on a shaker to obtain bacterial culture;

[0007] (2) Centrifuge the bacterial solution, take the precipitated bacterial sludge and add it to the anaerobic reaction buffer, then add water-soluble ferric salt solution, water-soluble cobalt source salt solution and water-soluble sulfur source salt solution; culture on a shaker to obtain microbial / polymetallic sulfide composite material.

[0008] This application describes a method for constructing a microbial / iron-cobalt-sulfur hybrid system with extremely high electrochemical activity, reproducibility, and bioactivity. This system involves transferring activated Shewanella bacteria into an anaerobic reaction system and adding iron, cobalt, and sulfur sources, enabling in-situ surface assembly and regeneration. This system combines the bioreduction activity of microorganisms with the catalytic properties of iron-cobalt-sulfur composite materials, achieving efficient electron transfer and self-regeneration of nanoparticles within the system, significantly improving the dechlorination degradation rate of halogenated pollutants. The hybrid system constructed in this application exhibits excellent reactivity and stability in carbon tetrachloride removal, achieving efficient conversion and harmless treatment of pollutants under mild conditions. This technology realizes the synergistic effect of microorganisms and polymetallic sulfides, overcoming the problems of easy aggregation, short reaction life, and low dechlorination rate of single bacterial cells in traditional nanomaterials. It has advantages such as simple operation, low cost, and high reusability, and can be widely applied to the remediation and treatment of halogenated organic pollutants in groundwater, industrial wastewater, and soil.

[0009] Preferably, in step (1), the volume ratio of the Shewanella inoculum to the LB medium is 0.1:100. Specifically, the Shewanella is Shewanella oneidensis MR-1 (purchased from the American Type Culture Collection Center, strain number ATCC700550).

[0010] Preferably, in step (1), the conditions for the shaker culture are: temperature of 30°C, shaking speed of 200 rpm, and time of 10~14h;

[0011] In step (1), the OD of the bacterial solution 600 The value is 2.5~3.

[0012] Preferably, in step (2), the centrifugation speed is 5000 rpm and the centrifugation time is 4~6 min;

[0013] Preferably, in step (2), the final concentration OD of the microbial / iron-cobalt-sulfur composite material is... 600 The value is 0.1.

[0014] Preferably, in step (2), the water-soluble trivalent iron salt is ferric chloride; the water-soluble cobalt source salt is cobalt chloride; and the water-soluble sulfur source salt is sodium thiosulfate.

[0015] Preferably, in step (2), the conditions for the shaker culture are: temperature of 30°C, rotation speed of 200 rpm, and time of more than 10 hours.

[0016] The second aspect of this application also provides a microbial / iron-cobalt-sulfur composite material, which is prepared by the above-described method.

[0017] A third aspect of this application also provides the application of the aforementioned microbial / iron-cobalt-sulfur composite material in the degradation of organic pollutants. Specifically, its application in the degradation of carbon tetrachloride.

[0018] Compared with the prior art, this application has the following advantages:

[0019] 1. This application describes a method for constructing a microbial / iron-cobalt-sulfur hybrid system with extremely high electrochemical activity, reproducibility, and biological activity by transferring activated Shewanella bacteria into an anaerobic reaction system and adding iron, cobalt, and sulfur sources. This system combines the bioreduction activity of microorganisms with the catalytic properties of iron-cobalt-sulfur composite materials, enabling efficient electron transfer and self-regeneration of nanoparticles within the system, significantly improving the dechlorination degradation rate of halogenated pollutants.

[0020] 2. The hybrid system constructed in this application exhibits excellent reactivity and stability in carbon tetrachloride removal, enabling efficient conversion and harmless treatment of pollutants under mild conditions. This technology achieves the synergistic effect of microorganisms and polymetallic sulfides, overcoming the problems of easy aggregation, short reaction life, and low dechlorination rate of single bacterial cells in traditional nanomaterials. It has the advantages of simple operation, low cost, and high reusability, and can be widely applied to the remediation and treatment of halogenated organic pollutants in groundwater, industrial wastewater, and soil. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in this application or the prior art, the drawings used in the description of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a SEM image of Shewanella.

[0023] Figure 2 SEM image of the microbial / iron-cobalt-sulfur composite material;

[0024] Figure 3 This is a TEM electron microscope image of Shewanella.

[0025] Figure 4 TEM image of the microbial / iron-cobalt-sulfur composite material;

[0026] Figure 5 XPS characterization of the microbial / iron-cobalt-sulfur composite material;

[0027] Figure 6 XRD characterization of the microbial / iron-cobalt-sulfur composite material;

[0028] Figure 7 The graph shows a comparison of carbon tetrachloride degradation. The six curves in the graph represent Shewanella / iron-cobalt-sulfur composite material, Shewanella / ferrous sulfide composite material, Shewanella, Shewanella / iron-cobalt-sulfur composite material + sodium lactate, Shewanella / ferrous sulfide composite material + sodium lactate, and Shewanella + sodium lactate. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] Unless otherwise specified, the experimental methods used in the embodiments of this application are all conventional methods.

[0031] In the following examples, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.

[0032] It should be noted that the Shewanella is Shewanella oneidensis MR-1 (purchased from the American Type Culture Collection Center, strain number ATCC700550).

[0033] Reagents:

[0034] LB medium: Weigh 10 g sodium chloride, 10 g tryptone and 5 g yeast extract and dissolve them in 1 L deionized water. Adjust the pH to about 7 with 1 mM HCl solution and 1 mM NaOH solution. Sterilize in an autoclave for 20 min at 121 ℃ and then cool before use.

[0035] M9 medium: Weigh 17.8 g disodium hydrogen phosphate dodecahydrate, 0.5 g sodium chloride, 3 g potassium dihydrogen phosphate, and 1 g ammonium chloride, dissolve them in 1 L of deionized water, adjust the pH to about 7 with 1 mM HCl solution and 1 mM NaOH solution, sterilize in an autoclave for 20 min at 121℃, and then cool before use.

[0036] PBS buffer: Weigh 0.12 g potassium dihydrogen phosphate, 0.72 g disodium hydrogen phosphate dodecahydrate, 4 g sodium chloride, and 0.1 g potassium chloride and dissolve them in 500 mL deionized water. Adjust the pH to approximately 7.4 with 1 mM HCl solution and 1 mM NaOH solution. Sterilize in an autoclave at 121℃ for 20 min before use.

[0037] Anaerobic reaction buffer (M9+5%LB) anaerobic culture medium: Weigh 16.8 g disodium hydrogen phosphate dodecahydrate, 0.975 g sodium chloride, 2.8 g potassium dihydrogen phosphate, 0.95 g ammonium chloride, 0.5 g tryptone, and 0.25 g yeast extract and dissolve them in 1 L deionized water. Adjust the pH to approximately 7 with 1 mM HCl solution and 1 mM NaOH solution, and pour the solution into an anaerobic bottle. Purge the solution and the upper air in the anaerobic bottle with 99.999% high-purity nitrogen gas for 40 min to ensure complete anaerobic conditions. After purging, measure the dissolved oxygen level using a dissolved oxygen meter. After purging, stopper the bottle, cap it, and sterilize it in an autoclave at 115°C for 30 min. Let it cool before use.

[0038] Example 1

[0039] The process of preparing the purchased bacteria into the experimental form is as follows:

[0040] The preparation method of Shewanella includes the following steps:

[0041] Preparation process: 1) Remove the glycerol tubes of Shewanella oneidensis MR-1 stored in a -80°C ultra-low temperature freezer. Under aseptic conditions, inoculate 400 µL of bacterial suspension into a 250 mL Erlenmeyer flask containing 100 mL of sterile LB medium and incubate overnight at 30°C on a shaker to activate the strain. Subsequently, in a laminar flow hood, use an inoculation loop to take an appropriate amount of activated bacterial suspension, streak it onto an LB solid medium plate, and incubate at 30°C for at least 12 hours. Pick a single colony and inoculate it into LB liquid medium, then incubate overnight at 30°C on a shaker at 200 rpm. The OD of the bacterial suspension is then measured. 600 When the value reaches 2.5~3, remove the bacterial solution and dilute or concentrate it appropriately according to the final concentration required for subsequent material synthesis experiments, so that it can be used.

[0042] (2) Place 300ml of M9+5%LB anaerobic culture medium into a 500ml anaerobic bottle, purge with nitrogen, autoclave, and then add sterile sodium lactate to a final concentration of 18 mM to obtain an anaerobic reaction buffer. Centrifuge the bacterial solution from step (1) at 5000 rpm for 5 minutes, and add the precipitated bacterial sludge to the 500ml anaerobic bottle to make the final concentration of Shewanella OD 18 mM. 600 =0.1; 500ml anaerobic bottles were placed in a constant temperature shaker at 30℃ and 200rpm for 12h to obtain Shewanella.

[0043] A method for preparing microbial / polymetallic sulfide composite materials includes the following steps:

[0044] (1) Take out the Shewanella oneidensis MR-1 glycerol tube (i.e., the Shewanella prepared from the purchased bacteria as required for the experiment) stored in the -80°C ultra-low temperature freezer. Under aseptic conditions, inoculate 400 µL of bacterial solution into a 250 mL Erlenmeyer flask containing 100 mL of sterile LB medium and incubate overnight at 30°C on a shaker to complete the activation of the strain. Subsequently, in a laminar flow hood, use an inoculation loop to take an appropriate amount of activated bacterial solution, streak it on an LB solid medium plate, and place it in a 30°C incubator for at least 12 h. Pick a single colony and inoculate it into LB liquid medium, and incubate overnight at 30°C and 200 rpm on a constant temperature shaker. When the OD600 value of the bacterial solution reaches 2.5~3, take it out and dilute or concentrate the bacterial solution appropriately according to the final concentration required for subsequent material synthesis experiments for use.

[0045] (2) Place 300ml of M9+5%LB anaerobic culture medium into a 500ml anaerobic bottle, purge with nitrogen, autoclave, and then add sterile sodium lactate to a final concentration of 18 mM to obtain an anaerobic reaction buffer. Centrifuge the bacterial solution from step (1) at 5000 rpm for 5 min, and add the precipitated bacterial sludge to the 500ml anaerobic bottle to make the final concentration of Shewanella OD 18 mM. 600 =0.1; then, ferric chloride solution, cobalt chloride solution and sodium thiosulfate solution with an initial concentration of 0.1M were added to the system so that the final concentrations of the three reached 100μM, 100μM and 200μM respectively (that is, the final concentrations of water-soluble ferric salt solution, water-soluble cobalt source salt solution and water-soluble sulfur source salt solution in a 500ml anaerobic bottle were 0.1mM, 0.1mM and 0.2mM respectively); the 500ml anaerobic bottle was placed in a constant temperature shaker at 30℃ and 200rpm for 14h to obtain Shewanella / ferric-cobalt-sulfur composite material.

[0046] Figure 1 This is a SEM image of Shewanella. Figure 2 This is a SEM image of the microbial / iron-cobalt-sulfur composite material.

[0047] like Figure 1 and Figure 2 It is evident that Shewanella is oval-shaped, and the constructed microbial / iron-cobalt-sulfur composite material contains distinct nanoparticles on the extracellular surface of Shewanella. During cultivation, the heterozygous cells gradually darkened visually, indicating a gradual increase in ferrous iron concentration.

[0048] Figure 3 This is a TEM electron microscope image of Shewanella. Figure 4 This is a TEM image of the microbial / iron-cobalt-sulfur composite material.

[0049] like Figure 3 and Figure 4 It can be seen that, as observed by TEM, the surface morphology of the bacteria becomes rough after encapsulation and is covered with heterogeneous nanoparticles; combined with Figure 6 XRD confirmed that the crystal structure of the particle was completely consistent with the encapsulated target material, and Figure 5 XPS further detected the presence of characteristic elements and their chemical valence states unique to this material on the bacterial surface, thus confirming the successful encapsulation of the material.

[0050] In an anaerobic workstation, the synthesized hybrid system was poured into centrifuge tubes and centrifuged at 6500 rpm for 5 min. The supernatant was discarded. The bottom precipitate was washed and resuspended with anoxic water three times, and centrifuged at 6500 rpm for 5 min, then the supernatant was discarded. The biomass in the sample was removed with acetone three times, and centrifuged at 6500 rpm for 5 min. The sample was then subjected to a second biomass removal with anhydrous ethanol, and centrifuged at 6500 rpm for 5 min twice. The sample was washed with anoxic water to remove organic solutions, and after repeated washing, centrifuged at 10000 rpm for 5 min, then the supernatant was discarded. The sample was frozen in an ultra-low temperature freezer at -80℃ for 2 h, and then freeze-dried in a freeze dryer for 10 h. After drying, the sample was ground into powder using a mortar and pestle in an anaerobic workstation. An appropriate amount of powder sample was taken for XRD and XPS elemental analysis and characterization. Figure 6 This is an XRD characterization image, which shows that the addition of cobalt resulted in an Fe-Co-S amorphous state. Figure 5 This is an XPS characterization image, which shows the presence of iron, cobalt, and sulfur, confirming the successful doping of cobalt; for example... Figure 5 and Figure 6 As shown, the presence of iron, cobalt, and sulfur can be confirmed, proving that the extracellular nanoparticles are iron-cobalt-sulfur.

[0051] Comparative Example 1

[0052] The preparation method of microbial / ferrous sulfide composite material includes the following steps:

[0053] Preparation process: 1) Take the glycerol tube of Shewanella oneidensis MR-1 stored in a -80°C ultra-low temperature freezer. Under aseptic conditions, inoculate 400 µL of bacterial solution into a 250 mL Erlenmeyer flask containing 100 mL of sterile LB medium and incubate overnight at 30°C on a shaker to activate the strain. Subsequently, in a laminar flow hood, use an inoculation loop to take an appropriate amount of activated bacterial solution, streak it on an LB solid medium plate, and incubate it in a 30°C incubator for at least 12 h. Pick a single colony and inoculate it into LB liquid medium, and incubate overnight at 30°C and 200 rpm on a constant temperature shaker. When the OD600 value of the bacterial solution reaches 2.5~3, remove it and dilute or concentrate the bacterial solution appropriately according to the final concentration required for subsequent material synthesis experiments for use.

[0054] (2) Place 300ml of M9+5%LB anaerobic culture medium into a 500ml anaerobic bottle, purge with nitrogen, autoclave, and then add sterile sodium lactate to a final concentration of 18 mM to obtain an anaerobic reaction buffer. Centrifuge the bacterial solution from step (1) at 5000 rpm for 5 minutes, and add the precipitated bacterial sludge to the 500ml anaerobic bottle to make the final concentration of Shewanella OD 18 mM. 600 =0.1; then, ferric chloride solution and sodium thiosulfate solution with an initial concentration of 0.1M were added to the system so that the final concentrations of the three reached 100μM and 100μM respectively; the 500ml anaerobic bottle was placed in a constant temperature shaker at 30℃ and 200rpm for 12h to obtain Shewanella / ferrous sulfide composite material.

[0055] Comparative Example 2

[0056] The preparation method of Shewanella includes the following steps:

[0057] (1) Take the glycerol tube of Shewanella oneidensis MR-1 stored in a -80°C ultra-low temperature freezer. Under aseptic conditions, inoculate 400 µL of bacterial culture into a 250 mL Erlenmeyer flask containing 100 mL of sterile LB medium and incubate overnight at 30°C on a shaker to complete the activation of the strain. Subsequently, in a laminar flow hood, use an inoculation loop to take an appropriate amount of activated bacterial culture and streak it on an LB solid medium plate, then place it in a 30°C incubator for at least 12 h. Pick a single colony and inoculate it into LB liquid medium, then incubate overnight at 30°C on a shaker at 200 rpm. Wait for the OD of the bacterial culture to be measured. 600 When the value reaches 2.5~3, remove the bacterial solution and dilute or concentrate it appropriately according to the final concentration required for subsequent material synthesis experiments, so that it can be used.

[0058] (2) Place 300ml of M9+5%LB anaerobic culture medium into a 500ml anaerobic bottle, purge with nitrogen, autoclave, and then add sterile sodium lactate to a final concentration of 18 mM to obtain an anaerobic reaction buffer. Centrifuge the bacterial solution from step (1) at 5000 rpm for 5 minutes, and add the precipitated bacterial sludge to the 500ml anaerobic bottle to make the final concentration of Shewanella OD 18 mM. 600 =0.1; 500ml anaerobic bottles were placed in a constant temperature shaker at 30℃ and 200rpm for 12h to obtain Shewanella.

[0059] Comparative Example 3

[0060] Figure 7 The Shewanella / iron-cobalt-sulfur composite material in the sample is combined with sodium lactate. The preparation process of the Shewanella / iron-cobalt-sulfur composite material is the same as in Example 1, except that sodium lactate is added during the degradation process.

[0061] The obtained Shewanella / iron-cobalt-sulfur composite material was removed from the anaerobic workstation and centrifuged at 6500 rpm for 7 min. It was then washed with PBS buffer, repeated three times. The washed Shewanella / iron-cobalt-sulfur composite material was resuspended in a 10 mL brown anaerobic bottle, a rotor was placed inside, and 10 mL of M9+ sodium lactate + Wolfe (Wollfeld vitamin solution) medium was added to the 10 mL anaerobic bottle to remove headspace, adjusting the final concentration of the hybrid system to OD0.05. 600 =1.

[0062] Comparative Example 4

[0063] Figure 7 The Shewanella / ferrous sulfide composite material in the sample is combined with sodium lactate. The preparation process of the Shewanella / ferrous sulfide composite material is the same as that of Comparative Example 1, except that sodium lactate is added during the degradation process.

[0064] The obtained Shewanella / ferrous sulfide composite material was removed from the anaerobic workstation and centrifuged at 6500 rpm for 7 min. It was washed with PBS buffer, repeated three times. The washed Shewanella / ferrous sulfide was resuspended in a 10 mL brown anaerobic flask, a rotor was placed inside, and 10 mL of M9+ sodium lactate + Wolfe (Wollfeld vitamin solution) medium was added to the 10 mL anaerobic flask to remove headspace, adjusting the final concentration of the hybrid system to OD0.05. 600 =1.

[0065] Comparative Example 5

[0066] Figure 7 The formula contains Shewanella bacteria and sodium lactate. The preparation process of Shewanella bacteria is the same as that in Comparative Example 2, except that sodium lactate is added during the degradation process.

[0067] The obtained Shewanella bacteria were removed from the anaerobic workstation and centrifuged at 5000 rpm for 5 min. They were then washed with PBS buffer, repeated three times. The washed Shewanella bacteria were resuspended in a 10 mL brown anaerobic flask, a rotor was placed inside, and 10 mL of M9+ sodium lactate + Wolfe (Wollfeld vitamin solution) medium was added to the 10 mL anaerobic flask to remove headspace, adjusting the final concentration of the hybrid system to OD0.05. 600 =1.

[0068] Test case

[0069] Microbial / iron-cobalt-sulfur composite material, microbial / ferrous sulfide composite material, Shewanella, microbial / iron-cobalt-sulfur composite material + sodium lactate, microbial / ferrous sulfide composite material + sodium lactate, and Shewanella + sodium lactate were used as comparative examples to verify the degradation effect of Shewanella / iron-cobalt-sulfur composite material constructed in Example 1 on carbon tetrachloride.

[0070] The Shewanella / iron-cobalt-sulfur composite material obtained in Example 1 was removed from the anaerobic workstation and centrifuged at 6500 rpm for 7 min. It was washed with PBS buffer, repeated three times. The washed Shewanella / iron-cobalt-sulfur composite material was resuspended in a 10 mL brown anaerobic bottle, a rotor was placed inside, and 10 mL of M9+Wolfe (Wolfe's vitamin solution) medium was added to the 10 mL anaerobic bottle to remove the headspace, adjusting the final concentration of the hybrid system to OD0.05. 600 =1, the experiment was conducted in a constant temperature room at 30℃. Sampling times were set at 0h, 2h, 4h, 6h, 8h, and 10h, with 1ml of sample taken each time. The obtained samples were extracted and the carbon tetrachloride concentration was measured using ECD, and degradation curves were plotted.

[0071] Figure 7 This is a graph showing the carbon tetrachloride degradation effect; within 4 hours, the Shewanella / iron-cobalt-sulfur composite material can completely degrade carbon tetrachloride, while Shewanella alone hardly degrades it, demonstrating that the Shewanella / iron-cobalt-sulfur composite material has a good carbon tetrachloride degradation effect; Figure 7As shown, the constructed Shewanella / ferric cobalt-sulfur composite material + sodium lactate exhibits a carbon tetrachloride removal efficiency 319.67 times that of Shewanella in Example 2 and 1.99 times that of the Shewanella / ferric cobalt-sulfur composite material. The carbon tetrachloride removal efficiency of the Shewanella / ferric cobalt-sulfur composite material is 160.96 times that of Shewanella in Example 2, highlighting the significant improvement in carbon tetrachloride degradation efficiency achieved by the Shewanella / ferric cobalt-sulfur composite material. The six curves in the figure represent: sw@FeCoS-Shewanella / ferric cobalt-sulfur composite material, sw@FeS-Shewanella / ferrous sulfide composite material, sw-Shewanella, sw@FeCoS+lac-Shewanella / ferric cobalt-sulfur composite material + sodium lactate, sw@FeS+lac-Shewanella / ferrous sulfide composite material + sodium lactate, and sw+lac-Shewanella + sodium lactate.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for preparing a microbial / polymetallic sulfide composite material, characterized in that, Includes the following steps: (1) Inoculate Shewanella into LB medium and culture on a shaker to obtain bacterial culture; (2) Centrifuge the bacterial solution, take the precipitated bacterial sludge and add it to the anaerobic reaction buffer, then add water-soluble ferric salt solution, water-soluble cobalt source salt solution and water-soluble sulfur source salt solution; culture on a shaker to obtain microbial / polymetallic sulfide composite material.

2. The method for preparing the microbial / polymetallic sulfide composite material according to claim 1, characterized in that, In step (1), the volume ratio of Shewanella inoculum to LB medium is 0.1:

100.

3. The method for preparing the microbial / polymetallic sulfide composite material according to claim 1, characterized in that, In step (1), the conditions for the shaker culture are: temperature 30℃, shaking speed 200rpm, and time 10~14h; In step (1), the OD of the bacterial solution 600 The value is 2.5~3.

4. The method for preparing the microbial / polymetallic sulfide composite material according to claim 1, characterized in that, In step (2), the centrifugation speed is 5000 rpm and the centrifugation time is 4~6 min.

5. The method for preparing the microbial / polymetallic sulfide composite material according to claim 1, characterized in that, In step (2), the final concentration OD of the microbial / iron-cobalt-sulfur composite material is... 600 The value is 0.

1.

6. The method for preparing the microbial / polymetallic sulfide composite material according to claim 1, characterized in that, In step (2), the water-soluble trivalent iron salt is ferric chloride; the water-soluble cobalt source salt is cobalt chloride; and the water-soluble sulfur source salt is sodium thiosulfate.

7. The method for preparing the microbial / polymetallic sulfide composite material according to claim 1, characterized in that, In step (2), the conditions for the shaker culture are: temperature of 30℃, rotation speed of 200rpm, and time of more than 10h.

8. A microbial / iron-cobalt-sulfur composite material, characterized in that, Microbial / iron-cobalt-sulfur composite material prepared by the method according to any one of claims 1 to 7.

9. The application of the microbial / iron-cobalt-sulfur composite material according to claim 8 in the degradation of organic pollutants.

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