Microbial slow-release material for ecological restoration of mine as well as preparation method and application of microbial slow-release material

Abstract

The invention discloses a microbial sustained-release material for ecological restoration of mines as well as a preparation method and application of the microbial sustained-release material, and belongs to the technical field of environmental protection. According to the microbial slow-release material provided by the invention, the components with proper mass percent are selected, and proper anaerobic microorganisms and aerobic microorganisms are further selected, so that the obtained microbial slow-release material has excellent stability and slow-release property; aerobic microorganisms and anaerobic microorganisms can be slowly released in the mine restoration process, so that the problems of acid regurgitation and plant degeneration in the mine ecological restoration process are excellently solved, and a long-acting and effective improvement effect is provided for mine ecological restoration; in addition, the preparation method of the microbial sustained-release material provided by the invention is simple to operate and beneficial to actual production.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental protection, and in particular relates to a microbial slow-release material for mine ecological restoration, and a preparation method and application thereof. Background Art

[0002] Mining is the main means for humans to obtain materials and energy necessary for social development. However, mining has also caused serious damage to the surrounding environment, such as ecological degradation, soil erosion and environmental pollution. Ores are often accompanied by a large number of metal minerals, which will oxidize or hydrolyze after being exposed to the air, causing serious heavy metal pollution. Therefore, it is of great social, ecological and economic significance to carry out ecological restoration of damaged mining areas, repair damaged habitats, eliminate the threat of mining areas to the surrounding environment, and restore the land use value of mining areas. Microbial technology has gradually become a research hotspot in the field of mine ecological restoration due to its advantages such as green, low-carbon, low cost and easy operation. In mining damaged land, such as spoil dumps, tailings ponds, waste rock piles and mining slopes, the soil microbial community is severely damaged. Due to the barrenness, acidity and heavy metal stress, the microbial biomass is sharply reduced, the biodiversity is poor, and the microbial ecological function is completely lost.

[0003] The microbial technology for mine restoration provided by the existing technology mainly builds a healthy soil microbial ecology by adding a variety of microorganisms with functions such as carbon, nitrogen and phosphorus circulation, plant growth promotion and heavy metal fixation to the soil, supports the growth of the surface vegetation system in the mining area, and thus achieves the goal of mine ecological restoration. However, on the one hand, there are many types of microorganisms required for mine restoration, and the production processes and storage conditions vary greatly; traditional microbial materials are mostly liquid or powder, and most of them are combinations of single functional strains. After being applied to the mine soil with harsh environment, not only the survival rate is low, but also multiple additions or supplements are required, resulting in waste of manpower and materials, and it is impossible to solve the problems existing in the mine at the same time; in addition, due to the long time period of mine ecological restoration, the time for different microorganisms to exert their effects is also different, so it is still necessary to add bacterial agents at different stages of ecological restoration; these have become obstacles to the large-scale application of microbial technology in the field of mine ecological restoration. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a microbial slow-release material for mine ecological restoration, which can simultaneously load different microorganisms required for mine restoration, and the microorganisms therein can be slowly released into the mine soil to be repaired, thereby achieving a good and lasting repair effect, and a preparation method and application thereof.

[0005] To achieve the above object, in a first aspect of the present invention, the present invention provides a microbial slow-release material for mine ecological restoration, characterized in that the microbial slow-release material comprises the following components in mass percentage:

[0006] Activated carbon particles 5-20%, microbial nutrients 57-72%, anaerobic microorganisms 0.5-1%, aerobic microorganisms 4.5-7%, adhesives 2.2-3.5%, and chitosan remainder;

[0007] The anaerobic microorganisms include at least one of Clostridium, Bacteroides, Desulfobacillus, Desulfococcus, and Desulfovibrio;

[0008] The aerobic microorganisms include at least one of nitrogen-fixing bacteria, Klebsiella, Freundii, Pseudomonas, Alcaligenes, and Frankia.

[0009] The present invention has been found through research that the present invention can simultaneously load more than two kinds of microorganisms required for mine ecological restoration by selecting components with appropriate mass percentages and further selecting appropriate anaerobic microorganisms and aerobic microorganisms to form a microbial slow-release material; moreover, the obtained microbial slow-release material has excellent stability and slow-release properties, and can slowly release aerobic microorganisms and anaerobic microorganisms therein during the mine restoration process, providing efficient and lasting improvement effects for mine ecological restoration; at the same time, the present invention has good compounding effects between the appropriate anaerobic microorganisms and aerobic microorganisms selected and between them and other components such as microbial nutrients, and can achieve excellent improvement of the problems of acid reflux and plant degradation in the process of mine ecological restoration.

[0010] As a preferred embodiment of the microbial sustained-release material of the present invention, the mass ratio of the anaerobic microorganisms to the aerobic microorganisms is 1:(8-10).

[0011] The present invention has found that when the mass ratio of anaerobic microorganisms to aerobic microorganisms is further selected to be 1:(8-10), the combination effect between the two is better. When applied to subsequent mine restoration, the pH value after restoration is closer to neutral, and the content of elements required for plant growth in the soil is higher, and the height of plants planted thereon is higher.

[0012] Preferably, the anaerobic microorganisms include Clostridium, Bacteroidetes and Desulfococcus.

[0013] More preferably, in the anaerobic microorganisms, the mass ratio of Clostridium, Bacteroides and Desulfococcus is 1:(1-2):(1-2).

[0014] Preferably, the aerobic microorganisms include nitrogen-fixing bacteria, Pseudomonas and Alcaligenes.

[0015] More preferably, in the aerobic microorganisms, the mass ratio of nitrogen-fixing bacteria, Pseudomonas and alcaligenes is 1:(0.5-2):(0.5-2).

[0016] As a preferred embodiment of the microbial sustained-release material of the present invention, the microbial nutrient comprises an organic nutrient and an inorganic nutrient, and the mass ratio of the organic nutrient to the inorganic nutrient is (20-30):1.

[0017] The present invention has found that the mass ratio of organic nutrients and inorganic nutrients in microbial nutrients will also affect the comprehensive effect of the product. When the microbial nutrients are further selected to include organic nutrients and inorganic nutrients within the above-mentioned mass ratio range, the obtained product will have a better restoration effect when applied to subsequent mine ecological restoration.

[0018] As a preferred embodiment of the microbial slow-release material of the present invention, the organic nutrient comprises at least one of sawdust, mushroom residue, coconut shell, corn cob, rice straw and wheat straw.

[0019] Preferably, the organic nutrient comprises coconut shell and rice straw.

[0020] More preferably, the mass ratio of the coconut shell to the rice straw is 1:(1-3).

[0021] As a preferred embodiment of the microbial slow-release material of the present invention, the inorganic nutrient includes at least one of urea, potassium dihydrogen phosphate, sodium sulfate, apatite and calcium sulfate.

[0022] Preferably, the inorganic nutrient comprises urea and apatite powder.

[0023] More preferably, the mass ratio of urea to apatite powder is (1-3):1.

[0024] As a preferred embodiment of the microbial sustained-release material of the present invention, the average particle size of the activated carbon particles is 2-3 mm.

[0025] The present invention has found that the average particle size of activated carbon particles will affect the loading effect of anaerobic microorganisms to a certain extent, and will also affect the sustained release effect of microbial sustained release materials. When the average particle size of activated carbon particles is further selected to be 2-3 mm, the comprehensive effect of the obtained product is better.

[0026] As a preferred embodiment of the microbial sustained-release material of the present invention, the adhesive comprises at least one of starch and sodium alginate.

[0027] In the second aspect of the present invention, the present invention provides a method for preparing the microbial sustained-release material, the preparation method comprising the following steps:

[0028] (1) soaking the activated carbon particles in an anaerobic microbial culture solution and then drying them to obtain activated carbon particles loaded with anaerobic microorganisms;

[0029] (2) culturing aerobic microorganisms on a solid culture medium and then crushing them to obtain solid culture medium particles containing aerobic microorganisms;

[0030] (3) mixing the solid culture medium particles containing aerobic microorganisms in step (2), microbial nutrients and a binder, and then embedding the activated carbon particles loaded with anaerobic microorganisms in step (1) under anaerobic conditions to obtain composite microbial particles;

[0031] (4) Encapsulating the composite microbial particles of step (3) with chitosan to obtain a microbial sustained-release material.

[0032] In the preparation method of the microbial sustained-release material provided by the present invention, anaerobic microorganisms are first loaded into activated carbon particles, solid culture medium particles containing aerobic microorganisms, microbial nutrients and adhesives are then mixed, the mixed substances are then embedded in the activated carbon particles loaded with anaerobic microorganisms, and finally the composite microbial particles are wrapped with chitosan, thereby obtaining a microbial sustained-release material with excellent stability and good sustained-release effect.

[0033] As a preferred embodiment of the preparation method of the present invention, in the step (1), the activation operation of the activated carbon particles is: placing the activated carbon particles at 400-500° C. and activating them with water vapor for 1.5-2.5 hours.

[0034] As a preferred embodiment of the preparation method of the present invention, in the step (1), the preparation method of the anaerobic microorganism culture solution is: adding anaerobic microorganisms to a liquid culture medium and culturing under anaerobic conditions for 70-74 hours.

[0035] Preferably, the liquid culture medium is at least one of a fortified clostridial culture medium, a brain heart infusion broth culture medium, and a sulfate-reducing bacteria culture medium.

[0036] As a preferred embodiment of the preparation method of the present invention, in the step (1), the drying is carried out under anaerobic conditions at 20-30° C. for 8-16 hours.

[0037] As a preferred embodiment of the preparation method of the present invention, in the step (2), the aerobic microorganisms are cultured on the solid culture medium for 44-52 hours.

[0038] Preferably, the solid culture medium is beef extract peptone medium

[0039] As a preferred embodiment of the preparation method of the present invention, in the step (2), the mesh size of the pulverization is less than 50 meshes.

[0040] As a preferred embodiment of the preparation method of the present invention, in the step (3), the microbial nutrients also include a step of sterilizing at 110-130° C. for 0.5-1.5 hours.

[0041] As a preferred embodiment of the preparation method of the present invention, in the step (3), the average diameter of the composite microbial particles is 4-6 mm.

[0042] The present invention has been found that when the parameters in the preparation process are further selected to be within the above range, the comprehensive effect of the obtained product is more excellent.

[0043] In the third aspect of the present invention, the present invention provides the application of the microbial slow-release material in the field of mine ecological restoration.

[0044] The microbial slow-release material provided by the present invention contains different types of microorganisms and can be effectively applied to mine ecological restoration to achieve a long-term and effective restoration effect.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The microbial slow-release material provided by the present invention is obtained by selecting components with appropriate mass percentages, and further selecting appropriate anaerobic microorganisms and aerobic microorganisms. The microbial slow-release material has excellent stability and slow-release properties, and can slowly release the aerobic microorganisms and anaerobic microorganisms therein during the mine restoration process, thereby achieving excellent improvement in the problems of acid reflux and plant degradation during the mine ecological restoration process, and providing a long-term and effective improvement effect for the mine ecological restoration; and the preparation method of the microbial slow-release material provided by the present invention is simple to operate and is conducive to actual production. DETAILED DESCRIPTION

[0047] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0048] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0049] The aerobic microorganisms and anaerobic microorganisms of the present invention can be conventional commercially available microorganisms, wherein the sources of the microorganisms used in the parallel examples and comparative examples remain consistent.

[0050] Specifically, for example, Clostridium, Pseudomonas, nitrogen-fixing bacteria, Bacteroides, Desulfobacillus, Alcaligenes, Klebsiella, etc. can be purchased from Ningbo Testo Biotechnology Co., Ltd. and Ningbo Mingzhou Biotechnology Co., Ltd.; Frankia and Freund's bacteria can be purchased from Beijing Kezhan Biotechnology Co., Ltd. and Wuhan Huizao Biotechnology Co., Ltd.; Desulfococcus and Desulfovibrio can be purchased from Wuhan Warner Biotechnology Co., Ltd.

[0051] Examples 1-3 and Comparative Examples 1-2

[0052] The embodiments and comparative examples of the present invention provide a microbial sustained-release material, the components (mass percentage) of the microbial sustained-release material are shown in Table 1;

[0053] Table 1

[0054]

[0055]

[0056] Among them, the average particle size of the activated carbon used in Examples 1-3 and Comparative Examples 1-2 is 2-3 mm;

[0057] The microbial nutrient comprises an organic nutrient and an inorganic nutrient in a mass ratio of 25:1, the organic nutrient comprises coconut shell and rice straw in a mass ratio of 1:2, and the inorganic nutrient comprises urea and apatite powder in a mass ratio of 2:1;

[0058] The binder is starch;

[0059] In Example 1 and Comparative Examples 1-2, the anaerobic microorganisms include Clostridium, Bacteroides and Desulfococcus in a mass ratio of 1:1:1; the aerobic microorganisms include nitrogen-fixing bacteria, Pseudomonas and Alcaligenes in a mass ratio of 1:1:1;

[0060] In Example 2, the anaerobic microorganisms include Clostridium, Bacteroides and Desulfococcus in a mass ratio of 1:2:2; the aerobic microorganisms include nitrogen-fixing bacteria, Pseudomonas and Alcaligenes in a mass ratio of 1:0.5:0.5;

[0061] In Example 3, the anaerobic microorganisms include Clostridium, Bacteroides and Desulfococcus in a mass ratio of 1:2:2; the aerobic microorganisms include nitrogen-fixing bacteria, Pseudomonas and Alcaligenes in a mass ratio of 1:2:2.

[0062] The method for preparing the microbial sustained-release material provided in Example 1 comprises the following steps:

[0063] (1) Activating the activated carbon with water vapor at 450° C. for 2 h, sieving, and collecting particles with an average particle size of 2-3 mm to obtain activated activated carbon;

[0064] (2) using a liquid culture medium (wherein Clostridium, Bacteroides and Desulfococcus are cultured in a reinforced Clostridium culture medium, a brain heart infusion broth culture medium and a sulfate-reducing bacteria culture medium, respectively) to culture anaerobic microorganisms under anaerobic conditions for 72 hours until the OD value reaches a plateau, then adding the activated carbon activated in step (1) to the mixed liquid culture medium and soaking for 24 hours, then filtering, and placing the filter residue under a nitrogen protection environment and drying it at room temperature for 12 hours to obtain activated carbon particles loaded with anaerobic microorganisms;

[0065] (3) placing the aerobic microorganisms in a solid culture medium (beef extract peptone culture medium) and culturing them for 48 hours, then crushing the aerobic microorganisms and the solid culture medium under sterile conditions to a particle size of less than 50 meshes to obtain solid culture medium particles containing aerobic microorganisms;

[0066] (4) drying the organic nutrient and crushing it to a particle size of less than 50 mesh, then mixing it with the inorganic nutrient and sterilizing it at 120° C. for 1 hour to obtain a sterilized microbial nutrient;

[0067] (5) mixing solid culture medium particles containing aerobic microorganisms, sterilized microbial nutrients and a binder, and embedding activated carbon particles loaded with anaerobic microorganisms under anaerobic conditions to prepare composite microbial particles with an average diameter of 5 mm;

[0068] (6) The composite microbial particles are coated with chitosan to obtain a microbial sustained-release material.

[0069] The preparation methods of the microbial sustained-release materials provided in Examples 2-3 and Comparative Examples 1-2 are consistent with that in Example 1, except that no relevant components are added.

[0070] Example 4

[0071] The embodiment of the present invention provides a microbial sustained-release material, which differs from the embodiment 1 in that the anaerobic microorganisms used are Bacteroides and Desulfobacillus at a mass ratio of 1:2, wherein the culture medium used for Desulfobacillus is the same as that for Desulfococcus, and the aerobic microorganisms are nitrogen-fixing bacteria, Freundlich, and Frankia at a mass ratio of 1:0.5:0.5;

[0072] The organic nutrients used are sawdust and mushroom residue in a mass ratio of 1:1, and the inorganic nutrients are potassium dihydrogen phosphate and sodium sulfate in a mass ratio of 2:1.

[0073] Example 5

[0074] The embodiment of the present invention provides a microbial sustained-release material. The difference between the microbial sustained-release material and the embodiment 1 is that the anaerobic microorganisms used are Bacteroides, Desulfococcus and Desulfovibrio in a mass ratio of 1:1:2, wherein the culture media used for Bacteroides, Desulfococcus and Desulfovibrio are brain heart infusion broth culture medium, sulfate-reducing bacteria culture medium and sulfate-reducing bacteria culture medium, respectively, and the aerobic microorganisms are nitrogen-fixing bacteria, Pseudomonas and Alcaligenes in a mass ratio of 1:2:1;

[0075] The organic nutrients used are corn cobs and rice straw in a mass ratio of 1:2, and the inorganic nutrients are apatite powder and calcium sulfate in a mass ratio of 1:1.

[0076] Example 6

[0077] The embodiment of the present invention provides a microbial sustained-release material. The difference between the microbial sustained-release material and the embodiment 1 is that the anaerobic microorganisms used are Bacteroides, Desulfococcus and Desulfovibrio in a mass ratio of 1:2:1, wherein the culture media used for Bacteroides, Desulfococcus and Desulfovibrio are brain heart infusion broth culture medium, sulfate-reducing bacteria culture medium and sulfate-reducing bacteria culture medium, respectively, and the aerobic microorganisms are nitrogen-fixing bacteria, Pseudomonas and Alcaligenes in a mass ratio of 1:0.5:2;

[0078] The organic nutrient used is wheat straw, and the inorganic nutrient is urea, potassium dihydrogen phosphate and sodium sulfate in a mass ratio of 1:1:1.

[0079] Example 7

[0080] The embodiment of the present invention provides a microbial sustained-release material. The difference between the microbial sustained-release material and the embodiment 1 is that the total amount of anaerobic microorganisms and aerobic microorganisms is kept unchanged, and the mass ratio of anaerobic microorganisms to aerobic microorganisms is 1:12.

[0081] Example 8

[0082] The embodiment of the present invention provides a microbial slow-release material. The difference between the microbial slow-release material and the embodiment 1 is that the total amount of the organic nutrient and the inorganic nutrient is kept unchanged, and the mass ratio of the organic nutrient to the inorganic nutrient is 10:1.

[0083] Example 9

[0084] The embodiment of the present invention provides a microbial sustained-release material. The difference between the microbial sustained-release material and the embodiment 1 is that the anaerobic microorganisms include Clostridium, Bacteroides and Desulfococcus in a mass ratio of 1:5:5.

[0085] Example 10

[0086] The embodiment of the present invention provides a microbial sustained-release material. The difference between the microbial sustained-release material and the embodiment 1 is that the aerobic microorganisms include Klebsiella, Freund's bacillus and Pseudomonas in a mass ratio of 1:4:5.

[0087] Comparative Example 3

[0088] The comparative example of the present invention provides a microbial sustained-release material, which is different from Example 1 in that the anaerobic microorganism is anaerobic ammonia-oxidizing bacteria (the culture medium is an anaerobic ammonia-oxidizing culture medium), and the aerobic microorganism is Nitrospira.

[0089] Comparative Example 4

[0090] The comparative example of the present invention provides a microbial sustained-release material, which is different from Example 1 in that the anaerobic microorganisms are acetogenic bacteria and Acinetobacter in a mass ratio of 1:2 (the culture medium of acetogenic bacteria and Acinetobacter is TYA culture medium), and the aerobic microorganisms are Pseudomonas aeruginosa and Thiobacillus ferrooxidans in a mass ratio of 1:2.

[0091] Comparative Example 5

[0092] The comparative example of the present invention provides a microbial material. The difference between the microbial material and Example 1 is that it only contains anaerobic microorganisms and aerobic microorganisms. The preparation method of this comparative example is:

[0093] (1) using a liquid culture medium (wherein Clostridium, Bacteroides, and Desulfococcus are cultured in a reinforced Clostridium culture medium, a brain heart infusion broth culture medium, and a sulfate-reducing bacteria culture medium, respectively) to culture anaerobic microorganisms under anaerobic conditions for 72 hours until the OD value reaches a plateau phase, and obtaining bacterial sludge;

[0094] (2) placing aerobic microorganisms in a solid culture medium (beef extract peptone culture medium) and culturing them for 48 hours, then crushing the aerobic microorganisms and the solid culture medium under sterile conditions to a particle size of less than 50 meshes to obtain solid culture medium particles containing aerobic microorganisms;

[0095] (3) Mixing bacterial sludge with solid culture medium particles containing aerobic microorganisms to obtain microbial material.

[0096] Effect example

[0097] The effect example of the present invention explores the effect of the microbial slow-release material prepared by Examples 1-10 and Comparative Examples 1-5 on mine restoration, comprising the following steps:

[0098] A potted experiment was conducted on slag collected from a pyrite mine in Guangdong to verify the effect of the prepared microbial slow-release material on mine remediation. The pH value of the collected slag was 2.87, the total organic carbon content was 8.3 mg / kg, the total nitrogen was 398 mg / kg, and the available phosphorus was 7.1 mg / kg. Implementation method of the potted experiment: 3 kg of slag, 100 g of organic fertilizer, and 100 g of cultivated soil were mixed, sterilized, placed in a flowerpot, 2 g of the prepared microbial slow-release material was applied, and 20 ryegrass seeds were planted. Slag samples were collected at 1 month and 3 months for analysis, and the pH value, total organic carbon, total nitrogen and available phosphorus of the slag samples were recorded, and the plant height was recorded; the results are shown in Table 2;

[0099] Table 2

[0100]

[0101]

[0102] It can be seen from Table 2 that when the technical solution provided by the present invention is adopted, the obtained product has an excellent and long-lasting effect of improving the mine ecology. In the third month of use, the pH value of the obtained slag is between 5.34-7.53, the total organic carbon is above 30.0 mg / kg, the total nitrogen is above 488 mg / kg, the available phosphorus is above 49.3 mg / kg, and the plant height is above 57.5 cm;

[0103] It can be seen from Example 1 and Comparative Examples 1-2 that when either anaerobic microorganisms or aerobic microorganisms are lacking, the obtained product has a poor effect on mine ecological restoration, the soil fertility is weak, and the plants cannot grow or die after 3 months; it can be seen from Example 1 and Comparative Examples 3-4 that when the selection of anaerobic microorganisms and aerobic microorganisms is not within the range given in the present invention, the obtained product does not have the function of mine ecological restoration, the soil pH and fertility are not improved, and the plants cannot grow; it can be seen from Example 1 and Comparative Example 5 that when only anaerobic microorganisms and aerobic microorganisms are provided but not prepared into the material form of the present invention, the obtained product has a weak long-term effect on slag restoration, the plant height is significantly lower than that of Example 1 at three months, and the pH value at three months also shows obvious acidity.

[0104] Finally, it should be noted that the above embodiments are for illustrating the technical solution of the present invention rather than limiting the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the technical solution of the present invention.

Claims

1. A microbial slow-release material for mine ecological restoration, characterized in that: The microbial sustained-release material comprises the following components in percentage by mass: Activated carbon particles 5-20%, microbial nutrients 57-72%, anaerobic microorganisms 0.5-1%, aerobic microorganisms 4.5-7%, adhesives 2.2-3.5%, and chitosan remainder; The anaerobic microorganisms include at least one of Clostridium, Bacteroides, Desulfobacillus, Desulfococcus, and Desulfovibrio; The aerobic microorganisms include at least one of nitrogen-fixing bacteria, Klebsiella, Freundii, Pseudomonas, Alcaligenes, and Frankia.

2. The microbial sustained-release material according to claim 1, characterized in that: The mass ratio of the anaerobic microorganisms to the aerobic microorganisms is 1:(8-10).

3. The microbial sustained-release material according to claim 1, characterized in that: The microbial nutrient comprises an organic nutrient and an inorganic nutrient, and the mass ratio of the organic nutrient to the inorganic nutrient is (20-30):

1.

4. The microbial sustained-release material according to claim 1, characterized in that: The organic nutrient comprises at least one of sawdust, mushroom residue, coconut shell, corn cob, rice straw and wheat straw; And / or, the inorganic nutrient includes at least one of urea, potassium dihydrogen phosphate, sodium sulfate, apatite, and calcium sulfate.

5. The microbial sustained-release material according to claim 1, characterized in that: The average particle size of the activated carbon particles is 2-3 mm.

6. The method for preparing the microbial sustained-release material according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: (1) soaking the activated carbon particles in an anaerobic microbial culture solution and then drying them to obtain activated carbon particles loaded with anaerobic microorganisms; (2) culturing aerobic microorganisms on a solid culture medium and then crushing them to obtain solid culture medium particles containing aerobic microorganisms; (3) mixing the solid culture medium particles containing aerobic microorganisms in step (2), microbial nutrients and a binder, and then embedding the activated carbon particles loaded with anaerobic microorganisms in step (1) under anaerobic conditions to obtain composite microbial particles; (4) Encapsulating the composite microbial particles of step (3) with chitosan to obtain a microbial sustained-release material.

7. The preparation method according to claim 6, characterized in that: In the step (1), the activation operation of the activated carbon particles is as follows: placing the activated carbon particles at 400-500° C. and activating them with water vapor for 1.5-2.5 hours; and / or, the method for preparing the anaerobic microorganism culture solution is: adding the anaerobic microorganisms to the liquid culture medium and culturing under anaerobic conditions for 70-74 hours; And / or, drying is performed under anaerobic conditions at 20-30° C. for 8-16 h.

8. The preparation method according to claim 6, characterized in that: In the step (2), the aerobic microorganisms are cultured on the solid medium for 44-52 hours; And / or, the crushing mesh size is less than 50 mesh.

9. The preparation method according to claim 6, characterized in that: In the step (3), the microbial nutrients also include a step of sterilizing at 110-130° C. for 0.5-1.5 hours; And / or, the average diameter of the composite microbial particles is 4-6 mm.

10. Use of the microbial slow-release material according to any one of claims 1 to 5 in the field of mine ecological restoration.

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