Magnetic metal organic framework material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of microbial electrochemistry, and particularly relates to a magnetic metal organic framework material as well as a preparation method and application thereof. The magnetic metal organic framework material obtained by the preparation method provided by the invention can improve the conductivity of the metal organic framework material, and by enhancing the electron transfer rate, enhancing H2 mass transfer and improving the loading capacity of functional bacteria, the starting time of a biological cathode is shortened, and the efficiency of producing acetic acid through microbial electro-catalysis is improved from multiple angles. Besides, through self-assembly preparation of the dissimilatory metal reducing bacteria mediated magnetic metal organic framework material, compared with a traditional magnetization modification process, the process has the advantages of being green and simple, and the problems that the process is complex and a non-environment-friendly modifier is used due to a traditional magnetization modification mode are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial electrochemistry, and specifically relates to a magnetic metal organic framework material and a preparation method and application thereof. Background Art

[0002] Since the Industrial Revolution, due to the continuous consumption of fossil energy by humans, CO in the atmosphere has 2 The concentration of greenhouse gas CO has increased dramatically, leading to an increasingly severe global climate crisis. 2 Emission reduction has become an urgent task facing all countries. Therefore, carbon emission reduction has become a major national strategic need.

[0003] Bioelectrocatalysis is an interdisciplinary research field that combines biocatalysis and electrocatalysis. It uses materials in biological systems as catalysts to catalyze redox reactions occurring at electrodes to achieve CO 2 Emission reduction and energy conversion. Microorganisms as low-cost catalysts have the advantages of wide sources, self-renewal, mild catalytic conditions, and green environmental protection. 2 However, the current microbial electrocatalytic acetic acid production devices still face some challenges, such as low electron transfer rate, H 2 The low mass transfer efficiency and insufficient biomass of acetogenic functional bacteria result in a long biocathode startup process and low acetogenic efficiency. These problems limit the application of microbial electrocatalysis in CO 2 Further development and application in the field of resource utilization.

[0004] Metal-organic frameworks (MOFs) are promising materials for enhancing H 2 Mass transfer and enrichment of functional bacteria make them ideal candidates for improving the electrocatalytic performance of microorganisms. However, the conductivity of metal organic framework materials cannot meet the requirements of enhancing the electron transfer rate, which in turn affects the efficiency of bioelectrocatalytic acetic acid production. Summary of the invention

[0005] The object of the present invention is to provide a magnetic metal organic framework material and a preparation method and application thereof. The magnetic metal organic framework material obtained by the method provided by the present invention can enhance the electron transfer rate, thereby improving the efficiency of bioelectrocatalytic acetic acid production.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing a magnetic metal organic framework material, comprising the following steps:

[0008] adding the raw materials into carbonate buffer, performing anaerobic treatment and sterilization to obtain a culture medium;

[0009] inoculating dissimilatory metal-reducing bacteria into the culture medium for culturing to obtain the magnetic metal-organic framework material;

[0010] The raw material is an iron-containing metal organic framework material or a non-iron-containing metal organic framework material;

[0011] When the raw material is a non-ferrous metal organic framework material, the raw material further comprises an auxiliary additive, and the auxiliary additive comprises ferrihydrite and / or ferrosoferric oxide.

[0012] Preferably, the iron-containing metal organic framework material comprises MIL-100(Fe).

[0013] Preferably, when the raw material is an iron-containing metal organic framework material, the raw material further comprises auxiliary additives, and the auxiliary additives include ferrihydrite and / or ferrosoferric oxide.

[0014] Preferably, the non-ferrous metal organic framework material comprises ZIF-8(Zn).

[0015] Preferably, the method for preparing the ferrihydrite comprises: under stirring, dropping a sodium hydroxide solution into a soluble iron salt solution until the pH value of the system reaches neutral, thereby obtaining the ferrihydrite.

[0016] Preferably, when the raw material is an iron-containing metal organic framework material and contains auxiliary additives, the molar ratio of the iron-containing metal organic framework material to the auxiliary additive is 4 to 1:1 based on the molar amount of the iron element; and the total iron concentration in the culture medium is 30 to 100 mmol / L.

[0017] Preferably, when the raw material is a non-ferrous metal organic framework material, the molar ratio of the non-ferrous metal organic framework material to the auxiliary additive is 4 to 1:1 based on the molar amount of the metal elements contained in the raw material; and the total concentration of metal elements in the culture medium is 50 mmol / L.

[0018] Preferably, the dissimilatory metal-reducing bacteria is Geobactersulfurreducens PCA;

[0019] The culture temperature is 10-40° C., and the curing time is 14-28 days.

[0020] The present invention also provides a magnetic metal organic framework material prepared by the preparation method described in the above technical solution.

[0021] The present invention also provides the use of the magnetic metal organic framework material described in the above technical solution in the preparation of acetic acid by microbial electrocatalysis.

[0022] The invention provides a method for preparing a magnetic metal organic framework material.

[0023] The magnetic metal organic framework material obtained by the preparation method provided by the present invention can improve the conductivity of the metal organic framework material by enhancing the electron transfer rate and H 2 Mass transfer and increase the functional bacteria load, thereby shortening the start-up time of the biocathode and improving the efficiency of microbial electrocatalytic acetic acid production from multiple angles. In addition, the present invention is prepared by self-assembly of magnetic metal organic framework materials mediated by dissimilatory metal-reducing bacteria. Compared with the traditional magnetization modification process, this process has the advantages of being green and simple, avoiding the problems of complex process and use of non-environmentally friendly modifiers brought about by the traditional magnetization modification method. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the preparation method provided by the present invention;

[0025] Figure 2 The schematic diagram of the device of the microbial electrochemical reactor in the present invention, wherein 1-DC power supply, 2-air bag, 3-adjustable pumping device, 4-magnetic stirrer, 5-iridium-plated tantalum-titanium mesh electrode, 6-cation exchange membrane, 7-carbon felt, 8-magnetic metal organic framework material;

[0026] Figure 3 X-ray diffraction patterns of the metal organic framework material and the magnetic metal organic framework material in Examples 1 to 2;

[0027] Figure 4 Cyclic voltammetry curves of the metal organic framework material and the magnetic metal organic framework material in Example 1;

[0028] Figure 5 is the X-ray diffraction pattern of the metal organic framework material and the magnetic metal organic framework material in Example 4;

[0029] Figure 6 is the X-ray diffraction pattern of the metal organic framework material and the magnetic metal organic framework material in Example 3;

[0030] Figure 7 X-ray diffraction patterns of the metal organic framework materials and magnetic metal organic framework materials in Examples 5 to 6;

[0031] Figure 8 OD of the acetogenic bacteria in the application example 600 curve;

[0032] Fig. 9 This is the variation curve of sodium acetate accumulation of acetic acid-producing bacteria in the application example;

[0033] Fig.10Biophase diagram before and after adding magnetic metal-organic framework materials in the application example. DETAILED DESCRIPTION

[0034] The present invention provides a method for preparing a magnetic metal organic framework material, comprising the following steps:

[0035] adding the raw materials into carbonate buffer, performing anaerobic treatment and sterilization to obtain a culture medium;

[0036] inoculating dissimilatory metal-reducing bacteria into the culture medium for culturing to obtain the magnetic metal-organic framework material;

[0037] The raw material is an iron-containing metal organic framework material or a non-iron-containing metal organic framework material;

[0038] When the raw material is a non-ferrous metal organic framework material, the raw material further comprises an auxiliary additive, and the auxiliary additive comprises ferrihydrite and / or ferrosoferric oxide.

[0039] The invention adds raw materials into carbonate buffer, performs anaerobic and sterilization treatments, and obtains culture medium.

[0040] In the present invention, the raw material is an iron-containing metal organic framework material or a non-iron-containing metal organic framework material.

[0041] In the present invention, the metal organic framework material is preferably MIL-100 (Fe). In the present invention, the non-ferrous metal organic framework material preferably includes ZIF-8 (Zn), and the ZIF-8 (Zn) is preferably commercially available ZIF-8 (Zn), CAS No.: 59061-53-9.

[0042] In the present invention, the preparation method of the MIL-100(Fe) preferably comprises: mixing trimesic acid and sodium hydroxide solution to obtain a mixed solution; and dropping the mixed solution into an aqueous solution of ammonium ferrous sulfate to react and obtain the MIL-100(Fe).

[0043] In the present invention, the concentration of trimesic acid in the mixed solution is preferably 3-7 mmol / L, more preferably 5-6 mmol / L; the concentration of sodium hydroxide is preferably 10-20 mmol / L, more preferably 15 mmol / L; the concentration of the aqueous solution of ammonium ferrous sulfate is preferably 5-10 mmol / L, more preferably 7.5-8 mmol / L; the volume ratio of the mixed solution to the aqueous solution of ammonium ferrous sulfate is preferably 15:32; the temperature of the reaction is preferably room temperature, the reaction is preferably carried out under stirring, and the stirring time is preferably 7h. In the present invention, after the reaction, it is also preferred to separate the obtained system, wash and dry the obtained precipitate; the washing preferably includes washing with deionized water and washing with ethanol in sequence; the drying temperature is preferably 60°C, and the drying method is preferably vacuum drying.

[0044] In the present invention, when the raw material is an iron-containing metal organic framework material, the raw material preferably further comprises an auxiliary additive, and the auxiliary additive preferably comprises ferrihydrite and / or ferrosoferric oxide. In the present invention, the particle size of the ferrosoferric oxide is preferably 20 to 50 nm.

[0045] In the present invention, the method for preparing ferrihydrite preferably comprises: under stirring, dropping a sodium hydroxide solution into a soluble iron salt solution until the pH value of the system reaches neutrality, thereby obtaining the ferrihydrite. In the present invention, the soluble iron salt solution preferably comprises a ferric chloride solution; the concentration of the soluble iron salt solution is preferably 0.7 mol / L; after reaching neutrality, it is also preferably included that the obtained system is centrifuged to remove the supernatant, the obtained precipitate is mixed with deionized water, the above process is repeated until the supernatant is light brown, and the precipitate is dried after separation.

[0046] In the present invention, the solvent of the carbonate buffer is preferably water; the carbonate buffer preferably comprises the following components: 1-5 g / L sodium bicarbonate, 0.1-1 g / L sodium dihydrogen phosphate, 0.1-3 g / L ammonium chloride, 0.1-0.3 g / L potassium chloride and 0.5-2 g / L sodium acetate.

[0047] In the present invention, when the raw material is an iron-containing metal-organic framework material and contains auxiliary additives, the molar ratio of the iron-containing metal-organic framework material to ferrihydrite is preferably 1 to 4:1, specifically 1:1, 2:1, 3:1 or 4:1, based on the molar amount of the iron element; the total iron concentration in the culture medium is preferably 30 to 100 mmol / L.

[0048] In the present invention, when the raw material is a non-ferrous metal organic framework material, the molar ratio of the non-ferrous metal organic framework material and the auxiliary additive is preferably 1 to 4:1, specifically 1:1, 2:1, 3:1 or 4:1, based on the molar amount of the metal elements contained in the raw material; the total concentration of metal elements in the culture medium is preferably 50 mmol / L.

[0049] The present invention has no particular limitation on the anaerobic and sterilization treatment process, and the process well known to those skilled in the art may be used.

[0050] After obtaining the culture medium, the present invention inoculates dissimilatory metal-reducing bacteria into the culture medium for culturing to obtain the magnetic metal-organic framework material.

[0051] In the present invention, the dissimilatory metal-reducing bacteria is preferably Geobacter sulfurreducens PCA (ATCC-51573). In the present invention, before the inoculation, the dissimilatory metal-reducing bacteria is preferably subjected to expanded culture, and the process of the expanded culture is preferably: after the dissimilatory metal-reducing bacteria are inoculated into NBAF culture medium for expanded culture, the obtained culture medium is centrifuged to obtain bacterial cells.

[0052] In the present invention, the culture temperature is preferably 10 to 40° C., and the curing time is preferably 14 to 28 days.

[0053] The schematic flow diagram of the preparation method provided by the present invention is as follows Figure 1 shown.

[0054] The present invention also provides a magnetic metal organic framework material prepared by the preparation method described in the above technical solution.

[0055] The present invention also provides the use of the magnetic metal organic framework material described in the above technical solution in the preparation of acetic acid by microbial electrocatalysis.

[0056] In the present invention, the application process preferably includes:

[0057] The magnetic metal organic framework material is added to the cathode chamber of the microbial electrochemical reactor, and an inoculation source is added to the cathode chamber. A DC power supply is used to provide a constant current to the reactor, and an air bag and a pumping device are used to realize the CO 2 The circulation of the pumping device is adjusted to maintain pH stability and catalyze CO 2 conversion.

[0058] In the present invention, the microbial electrochemical reactor is preferably a double-chamber reactor made of acrylic material with a cation exchange membrane in the middle; wherein the anode is preferably an iridium-plated tantalum-titanium mesh, and the cathode is preferably a carbon felt. In the present invention, the constant current is preferably 50 to 300 mA. The present invention has no special limitation on the type of the inoculation source, and those familiar to those skilled in the art can be used.

[0059] In the present invention, the flow rate of the pumping device is preferably adjustable within a range of 0-100 SCCM, and the flow rate adjustment method preferably includes timed intermittent pumping or gas flow rate adjustment. In the present invention, the pH stability range is preferably 6-7.

[0060] In the present invention, the method for calculating the sodium acetate yield preferably includes: forming a linear relationship between a gradient concentration standard and a gas chromatographic peak area, and then taking a water sample from the cathode chamber to measure the gas chromatographic peak area of ​​sodium acetate therein to obtain the corresponding concentration, that is, to determine the yield.

[0061] In the present invention, the schematic diagram of the device of the microbial electrochemical reactor is as follows Figure 2 As shown, 1 is a DC power supply, 2 is an air bag, 3 is an adjustable air pump device, 4 is a magnetic stirrer, 5 is an iridium-plated tantalum-titanium mesh electrode, 6 is a cation exchange membrane, 7 is a carbon felt, and 8 is a magnetic metal organic framework material.

[0062] Unless otherwise specified, the materials and equipment used in the present invention are all commercially available products in the art.

[0063] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] Example 1

[0065] Preparation of metal organic framework materials:

[0066] Trimesic acid (5 mM) and an aqueous sodium hydroxide solution (15 mM) were mixed to obtain a mixed solution, and 15 mL of the mixed solution was added dropwise to 32 mL of an aqueous solution of ammonium ferrous sulfate (7.5 mM), while stirring at room temperature for 7 hours; the precipitate was separated by centrifugation, washed with deionized water and ethanol, respectively, and then dried in vacuum at 60° C. to obtain MIL-100(Fe);

[0067] Preparation of ferrihydrite:

[0068] Under stirring conditions, sodium hydroxide solution was added dropwise to the FeCl solution with a concentration of 0.7 M.3 The solution is stirred until the pH value of the system reaches about 7; the supernatant is removed by centrifugation and mixed with deionized water, and this process is repeated until the supernatant is light brown. After separation, the precipitate is dried to obtain ferrihydrite;

[0069] Bacterial expansion culture:

[0070] The Geobactersulfurreducens PCA was inoculated into NBAF medium for expansion culture, and the NBAF medium containing the Geobactersulfurreducens PCA was centrifuged to obtain bacterial cells;

[0071] Preparation of magnetic metal-organic framework materials:

[0072] The carbonate buffer is placed in an anaerobic serum bottle, and the MIL-100 (Fe) and ferrihydrite obtained above are added to the carbonate buffer, and anaerobic and sterilized to obtain a culture medium; wherein the carbonate buffer comprises 1.5 g / L sodium bicarbonate, 0.6 g / L sodium dihydrogen phosphate, 1.5 g / L ammonium chloride, 0.1 g / L potassium chloride and 1.64 g / L sodium acetate, and the total iron concentration in the culture medium is in the range of 50 mM, and the molar ratio of the metal organic framework material to ferrihydrite is 1:1 based on the molar amount of the iron element;

[0073] Then, the bacterial cells obtained above were inoculated into a culture medium for culture, wherein the culture temperature was 30° C. and the curing time was 15 days, thereby obtaining the magnetic metal organic framework material.

[0074] Figure 3 The X-ray diffraction patterns of the metal organic framework material and the magnetic metal organic framework material obtained in this example are as follows: Figure 3 It can be seen that the magnetic metal-organic framework material (1:1) prepared according to the molar ratio of the metal-organic framework material to ferrihydrite of 1:1 adds a characteristic peak representing ferrosoferric oxide on the basis of maintaining the characteristic peaks of the metal-organic framework material.

[0075] Figure 4 The cyclic voltammetry curves of the metal organic framework material and the magnetic metal organic framework material obtained in this example are as follows: Figure 4 It can be seen that the magnetic metal organic framework material has an obvious oxidation peak with a potential of -0.93 V. Relative to the potential of the metal organic framework material (-0.89 V), the position of this peak is more negative, which indicates that the magnetic metal organic framework material is more susceptible to oxidation reactions.

[0076] Example 2

[0077] A magnetic metal organic framework material was prepared in the manner of Example 1, except that the molar ratio of the metal organic framework material to ferrihydrite was 2:1.

[0078] Figure 3 The X-ray diffraction patterns of the metal organic framework material and the magnetic metal organic framework material obtained in this example are as follows: Figure 3 It can be seen that the magnetic metal-organic framework material (2:1) prepared according to the molar ratio of the metal-organic framework material to ferrihydrite of 2:1 showed the characteristic peak of ferrosoferric oxide, which indicates that the synthesis of the magnetic metal-organic framework can still be achieved after changing the molar ratio of the metal-organic framework material to ferrihydrite.

[0079] Example 3

[0080] Preparation of magnetic metal-organic framework materials:

[0081] The carbonate buffer was placed in an anaerobic serum bottle, and the MIL-100 (Fe) prepared in Example 1 and the commercially available Fe with a particle size of 20 to 50 nm were added. 3 O 4 Add to carbonate buffer, perform anaerobic and sterilization treatment to obtain a culture medium; wherein the carbonate buffer includes 1.5 g / L sodium bicarbonate, 0.6 g / L sodium dihydrogen phosphate, 1.5 g / L ammonium chloride, 0.1 g / L potassium chloride and 1.64 g / L sodium acetate, and the total iron concentration in the culture medium is 50 mM. In terms of the molar amount of iron element, the metal organic framework material and Fe 3 O 4 The molar ratio is 4:1;

[0082] Then, the bacterial cells obtained above were inoculated into a culture medium for cultivation, wherein the culture temperature was 30° C. and the curing time was 7 days, thereby obtaining the magnetic metal organic framework material.

[0083] Figure 6 The X-ray diffraction patterns of the metal organic framework material and the magnetic metal organic framework material obtained in this example are as follows: Figure 6 It can be seen that the magnetic metal-organic framework material has added a characteristic peak representing ferrosoferric oxide on the basis of maintaining the characteristic peaks of the metal-organic framework material.

[0084] Example 4

[0085] Preparation of magnetic metal-organic framework materials:

[0086] The carbonate buffer is placed in an anaerobic serum bottle, and the MIL-100 (Fe) prepared in Example 1 is added to the carbonate buffer, and anaerobic and sterilization treatment is performed to obtain a culture medium; wherein the carbonate buffer comprises 1.5 g / L sodium bicarbonate, 0.6 g / L sodium dihydrogen phosphate, 1.5 g / L ammonium chloride, 0.1 g / L potassium chloride and 1.64 g / L sodium acetate, and the total iron concentration in the culture medium is in the range of 50 mM;

[0087] Then, the bacterial cells obtained above were inoculated into a culture medium for culture, wherein the culture temperature was 30° C. and the curing time was 21 days, thereby obtaining the magnetic metal organic framework material.

[0088] Figure 5 The X-ray diffraction patterns of the metal organic framework material and the magnetic metal organic framework material obtained in this example are as follows: Figure 6 It can be seen that the magnetic metal-organic framework material has added a characteristic peak representing ferrosoferric oxide on the basis of maintaining the characteristic peaks of the metal-organic framework material.

[0089] Example 5

[0090] A magnetic metal organic framework material was prepared in the manner of Example 1, except that MIL-100(Fe) was replaced by commercially available ZIF-8(Zn) (CAS No.: 59061-53-9). The obtained magnetic metal organic framework material was recorded as ZIF-8(Zn)-SW.

[0091] Example 6

[0092] A magnetic metal organic framework material was prepared in the manner of Example 3, except that MIL-100(Fe) was replaced by commercially available ZIF-8(Zn) (CAS No.: 59061-53-9). The obtained magnetic metal organic framework material was recorded as ZIF-8(Zn)-SS.

[0093] Figure 7 The X-ray diffraction patterns of the metal organic framework material and the magnetic metal organic framework material obtained in Example 5 and Example 6 are as follows: Figure 7 It can be seen that the magnetic metal organic framework materials obtained in Example 5 and Example 6 both have characteristic peaks representing ferrosoferric oxide while maintaining the characteristic peaks of ZIF-8 (Zn).

[0094] Application Examples

[0095] Preparation of inoculum for microbial electrochemical reactor:

[0096] The pure bacteria of acetic acid-producing bacteria (Acetobacterium woodii) are inoculated into an anaerobic serum bottle containing acetic acid bacteria culture medium for expansion culture. The culture time is 48 hours to obtain the inoculum of the microbial electrochemical reactor;

[0097] The acetic acid bacteria culture medium includes 1g / L ammonium chloride, 0.33g / L potassium dihydrogen phosphate, 0.45g / L potassium hydrogen phosphate, 0.1g / L magnesium sulfate heptahydrate, 2g / L yeast extract, 10g / L sodium bicarbonate, 0.5g / L cysteine, and 0.5g / L sodium sulfide nonahydrate.

[0098] Figure 8 OD during the culture of Acetobacterium woodii 600 Curve, from Figure 8 It can be seen that the OD of acetic acid producing bacteria was 48h. 600 Becoming stable.

[0099] Fig. 9 The cumulative amount of sodium acetate changes during the cultivation of acetic acid-producing bacteria (Acetobacterium woodii). Fig. 9 It can be seen that the acetic acid-producing bacteria entered the rapid acetic acid production stage after 48 hours, which meets the inoculation requirements.

[0100] The magnetic metal organic framework material obtained in the example was added to the cathode chamber of the microbial electrochemical reactor, and the cultured acetogenic bacteria (Acetobacterium woodii) was used as an inoculation source. The amount of inoculated bacterial liquid was 10% of the cathode volume. A DC power supply provided a constant current condition for the reactor. An air bag and a pumping device were used to realize the CO 2 The pump gas flow rate of the pump gas device is adjusted to maintain pH, wherein the anode is an iridium-plated tantalum titanium mesh, the cathode is a carbon felt, and the constant current is 100 mA; the CO 2 The flow rate was 5 SCCM, the pH value was controlled to be stable at 6.5, and CO 2 The blank group was used without adding magnetic metal organic framework materials, and the control group was used with adding metal organic framework materials.

[0101] By comparing the differences in sodium acetate production among the experimental group, blank group and control group, the enhancing effect of the magnetic metal organic framework material on the electrochemical acetic acid production of microorganisms was determined; the calculation method of the sodium acetate production was as follows: first, a linear relationship was formed between a gradient concentration standard and a gas chromatographic peak area, and then a water sample from the cathode chamber was taken to determine the gas chromatographic peak area of ​​sodium acetate therein to calculate the corresponding concentration.

[0102] Fig.10 The biological phase diagram before and after the addition of the magnetic metal organic framework material obtained in Example 1, from Fig.10 Under the same culture conditions, the abundance of acetic acid-producing functional bacteria (Acetobacteriumwoodii) in the experimental group with the addition of magnetic metal-organic framework materials reached 42%, which is 1.4 times that of the blank group (29%).

[0103] Table 1 shows the dissolved H before and after adding magnetic metal organic framework materials 2 Concentration (mg / L) change results

[0104] 5 minutes 10 minutes 15 minutes 20 minutes 25 minutes 30 minutes 35 minutes 40 minutes MIL-100(Fe) 0.41 0.62 0.77 0.83 0.91 0.95 1.05 1.09 ZIF-8(Zn) 0.32 0.47 0.59 0.77 0.84 0.90 0.93 0.95 Blank Group 0.21 0.32 0.44 0.61 0.74 0.86 0.90 0.92 Example 1 0.57 0.89 0.95 0.98 1.02 1.11 1.13 1.15 Example 2 0.45 0.67 0.80 0.87 0.95 0.99 1.07 1.10 Example 3 0.43 0.64 0.77 0.85 0.93 0.97 1.07 1.11 Example 4 0.44 0.59 0.83 0.90 0.99 1.04 1.07 1.09 Example 5 0.35 0.51 0.62 0.83 0.88 0.94 0.99 1.02 Example 6 0.38 0.55 0.68 0.87 0.92 0.97 1.04 1.08

[0105] It can be seen from Table 1 that the addition of magnetic metal organic framework materials can significantly improve H 2 Dissolution rate and amount in solution.

[0106] Table 2 shows the change in sodium acetate concentration (g / L) before and after the addition of magnetic metal organic framework materials

[0107] 5 days 10 days 15 days 20 days 25 days 30 days MIL-100(Fe) 1.5 2.9 5.4 7.2 8.6 11.4 ZIF-8(Zn) 1.3 2.7 4.8 6.6 7.9 9.8 Blank Group 1.1 2.3 4.2 5.7 7.3 9.1 Example 1 1.8 5.1 9.5 12.9 16.4 19.5 Example 2 1.6 3.3 8.1 11.6 14.8 16.9 Example 3 1.3 2.7 5.9 7.7 9.5 11.9 Example 4 1.1 2.4 6.1 8.2 10.2 12.7 Example 5 1.3 3.3 5.5 7.4 8.3 10.4 Example 6 1.4 3.1 5.7 7.6 8.8 10.9

[0108] It can be seen from Table 2 that the cumulative amount of sodium acetate in the experimental group adding the optimal ratio (Example 1) to obtain the magnetic metal organic framework material on the 20th day was 2.1 times and 1.7 times that of the blank group and the control group (MIL-100 (Fe)), respectively.

[0109] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing a magnetic metal organic framework material, characterized in that: The following steps are involved: adding the raw materials into carbonate buffer, performing anaerobic treatment and sterilization to obtain a culture medium; inoculating dissimilatory metal-reducing bacteria into the culture medium for culturing to obtain the magnetic metal-organic framework material; The raw material is an iron-containing metal organic framework material or a non-iron-containing metal organic framework material; When the raw material is a non-ferrous metal organic framework material, the raw material further comprises an auxiliary additive, and the auxiliary additive comprises ferrihydrite and / or ferrosoferric oxide.

2. The preparation method according to claim 1, characterized in that: The iron-containing metal organic framework material includes MIL-100 (Fe).

3. The preparation method according to claim 1 or 2, characterized in that: When the raw material is an iron-containing metal organic framework material, the raw material further comprises an auxiliary additive, and the auxiliary additive comprises ferrihydrite and / or ferrosoferric oxide.

4. The preparation method according to claim 1, characterized in that: The non-iron-containing metal organic framework material includes ZIF-8(Zn).

5. The preparation method according to claim 1 or 3, characterized in that: The preparation method of the ferrihydrite comprises: under stirring conditions, dropping a sodium hydroxide solution into a soluble iron salt solution until the pH value of the system reaches neutral, thereby obtaining the ferrihydrite.

6. The preparation method according to claim 3, characterized in that: When the raw material is an iron-containing metal organic framework material and contains auxiliary additives, the molar ratio of the iron-containing metal organic framework material to the auxiliary additive is 4 to 1:1 based on the molar amount of the iron element; and the total iron concentration in the culture medium is 30 to 100 mmol / L.

7. The preparation method according to claim 1, characterized in that: When the raw material is a non-ferrous metal organic framework material, the molar ratio of the non-ferrous metal organic framework material to the auxiliary additive is 4-1:1 based on the molar amount of the metal elements contained in the raw material; the total concentration of the metal elements in the culture medium is 50mmol / L.

8. The preparation method according to claim 1, characterized in that: The dissimilatory metal-reducing bacteria is Geobactersulfurreducens PCA; The culture temperature is 10-40° C., and the curing time is 14-28 days.

9. The magnetic metal organic framework material prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the magnetic metal organic framework material according to claim 9 in the preparation of acetic acid by microbial electrocatalysis.

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