A kind of trace element coal gangue soil repair agent and preparation method thereof

Abstract

The invention discloses a soil repair agent based on trace elements of coal gangue and a preparation method thereof, which belongs to the technical field of soil repair agents, and comprises the following steps: mixing dark fermentation strains with beneficial soil bacteria to obtain composite strains, coating the composite strains with starch, and then mixing with a bio-based foaming agent to obtain a composite foaming agent; mixing modified cellulose, a composite foaming agent, coal gangue powder and a gelling agent to obtain a hydrogel, and freeze-drying to obtain a loaded coal gangue particle aerogel; mixing the loaded coal gangue particle aerogel with trace elements, adding peat soil, lignite, vermiculite, and corn stalks for stirring, and drying and packaging to obtain a soil repair agent. The starch-encapsulated strains in the composite foaming agent have better stability and can be better propagated and developed in the soil; the encapsulated hydrogen-producing strains can better complete the dark fermentation reaction, increase the biohydrogen content in the soil, and restore soil fertility.

Description

Technical Field

[0001] The present invention belongs to the technical field of soil remediation agents, and in particular, relates to a soil remediation agent based on trace elements and gangue and a preparation method thereof. Background Art

[0002] Soil remediation agents are substances used to improve soil quality and solve soil pollution problems. These remediation agents can reduce the content of pollutants in the soil, increase soil fertility, and improve soil structure through various mechanisms, thereby improving plant growth and yield. Among them, silicate remediation agents such as sodium silicate and calcium silicate can increase the stability of soil structure and improve soil loading capacity, and have a certain effect on repairing contaminated soil. Microbial remediation agents such as degrading bacteria and antibiotic bacteria can decompose pollutants, reduce their toxicity, and promote soil remediation. At the same time, they form a symbiotic relationship with other microorganisms in the soil, increase soil biodiversity, have the effect of improving soil structure, can solve the problem of soil compaction, and improve the soil microecological environment.

[0003] Although soil remediation agents can improve soil quality, increase plant growth and yield, they also have some defects. Some soil remediation agents may change the physical and chemical properties of the soil, such as affecting the air permeability, water holding capacity and water conductivity of the soil, and have side effects on the physical environment of the soil; secondly, some remediation agents may change the bulk density and density of the soil to varying degrees when added, thereby causing changes in the soil water holding capacity, and may reduce the capillary porosity and air permeability of the soil, causing a decrease in soil water storage; in addition, if the remediation agent is used improperly or excessively, it may cause adverse effects on the environment and humans and animals. For example, some remediation agents may have adverse effects on plants, beneficial microorganisms in the soil, and the environment. Summary of the invention

[0004] The purpose of the present invention is to provide a soil repair agent based on trace elements of coal gangue and a preparation method thereof: starch-coated bacteria are mixed with a mixture, the starch-encapsulated bacteria have better stability and can be better propagated and developed in the soil; cellulose is modified by dopamine hydrochloride to form metal ion coordination bonds with metal oxides in the coal gangue, so that the trace elements in the coal gangue can be evenly distributed in the soil repair agent system; modified cellulose, a composite, coal gangue powder and a gelling agent are mixed to form an aerogel loaded with coal gangue particles, and components such as alumina and silicon dioxide in the coal gangue can promote the cross-linking degree of the cellulose gel, so that the aerogel prepared from the cellulose gel has better stability and is more conducive to the complete preservation of the soil restoration agent; the aerogel loaded with coal gangue particles is mixed with trace elements, stirred, dried and packaged to obtain a soil repair agent that not only has good soil repair performance, but also the added additives can be better dispersed in the soil system to play a repairing role.

[0005] The purpose of the present invention is to provide a method for preparing a trace element gangue soil repair agent to solve the problems raised in the background technology.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing a trace element gangue soil repair agent comprises the following steps:

[0008] S1. The gangue is washed with deionized water and ground into powder to obtain gangue powder;

[0009] Among them, deionized water is used to wash the coal gangue powder to remove ions and minerals in the coal gangue powder to obtain pure coal gangue powder to promote the growth and development of plants and improve the yield and quality of crops; the coal gangue powder is ground to have a uniform particle size distribution, and the contact area between the coal gangue and the soil is increased, the porosity of the soil is increased, the aeration and drainage properties of the soil are improved, and it is beneficial to the growth and development of plants.

[0010] S2. The dark fermented bacteria are mixed with beneficial soil bacteria to obtain a composite bacteria, the composite bacteria are coated with starch, and then mixed with the mixture to obtain a composite; specifically comprising the following steps:

[0011] A1. 8.5 g corn starch was added to 80 mL deionized water, stirred at 80 ° C for 3 min until the starch was completely gelatinized, cooled to room temperature, dark fermentation bacteria and soil beneficial bacteria were added, stirred at 600 rpm for 3 min to allow the bacteria to fully contact the starch, and dried overnight in a dark environment to obtain starch-coated bacteria;

[0012] Among them, the hydroxyl groups in starch can combine with the oxygen-containing functional groups of the Clostridium bacteria through hydrogen bonds, and starch has good adsorption and film-forming properties, which can effectively wrap the bacteria to form a protective film, thereby protecting the bacteria from the influence of the external environment. Starch can also provide certain nutrients, promote the growth and reproduction of microorganisms, improve the plant's stress resistance and disease resistance, and promote plant growth and development.

[0013] Furthermore, the dark fermentation bacteria is at least one of Clostridium, Desulfovibrio, Enterobacter, and Escherichia.

[0014] Furthermore, the clostridium is mixed with Clostridium butyricum, Clostridium acetobutyricum, Clostridium difficile, Clostridium tyrobutyricum, and Clostridium pasteurianum in a dosage ratio of (0.1-0.3):(0.2-0.4):(0.3-0.4):(0.4-0.6):(0.1-0.2).

[0015] Furthermore, the beneficial bacteria in the soil are at least one of nitrogen-fixing bacteria, rhizobia, actinomycetes, lactic acid bacteria, yeasts, and molds.

[0016] Furthermore, the dosage ratio of dark fermentation bacteria and soil beneficial bacteria is (1.3-1.7):(1.5-1.7) g.

[0017] A2. Prepare 5 g of rosin, 2 g of natural cellulose, 2.5 g of chitosan, and 1.5 g of gelatin, wash them with deionized water, dry them, and grind them into particles in a grinder. Add 6.5 g of sodium hydroxide to 20 mL of deionized water, heat it to 75°C, add 2.5 g of the particles, place it in a 100°C water bath, and stir for 2 hours. During this period, add deionized water to the volume of the above reaction system to 20 mL. Cool it to 45°C, add 1.25 g of gelatin, and stir until small bubbles appear on the surface to obtain a mixture. Mix 0.7 g of starch-coated bacteria with 8 g of the mixture to obtain a composite.

[0018] Among them, during the mixing process, the hydroxyl groups of starch on the surface of the starch-coated bacteria combine with the hydrogen bonds in the foaming agent molecules to form a complex. When the complex is subjected to high temperature or other stimuli, it will release hydrogen gas to play a foaming role. Due to the presence of starch, the complex also has good biodegradability and is environmentally friendly.

[0019] Furthermore, the usage ratio of rosin, natural cellulose, chitosan and gelatin is (4-6):(1-3):(2-3):(1-2).

[0020] Furthermore, the dosage ratio of sodium hydroxide, deionized water and particles is (6-7) g:(10-30) mL:(2-3) g.

[0021] Furthermore, the ratio of starch-coated bacteria to the mixture is (0.5-0.9) g:(7-9) g;

[0022] S3. Modifying cellulose with dopamine hydrochloride to obtain modified cellulose, mixing the modified cellulose, the composite, gangue powder and epichlorohydrin to obtain a hydrogel, and freeze-drying to obtain a gangue particle-loaded aerogel;

[0023] Furthermore, the modified cellulose is specifically prepared by adding 6.5 g of cellulose and 2 g of dopamine hydrochloride to 50 mL of Tris buffer having a pH of 8, stirring evenly, introducing argon gas, stirring at 50° C. for 12 h, and freeze-drying the obtained solution in a freeze dryer to obtain the modified cellulose;

[0024] Among them, the hydroxyl groups contained in the cellulose surface can react with the amine groups in dopamine hydrochloride, so that dopamine hydrochloride is grafted on the cellulose surface, providing catechol functional groups, which can interact through metal ion coordination bonds and hydrogen bonds, so that the coal gangue powder and the complex are evenly dispersed in the cellulose gel system.

[0025] Furthermore, the usage ratio of cellulose, dopamine hydrochloride and Tris buffer is (6-7) g:(1-3) g:(1-2) mL.

[0026] Furthermore, the loaded gangue particle aerogel is specifically prepared by the following steps: adding 0.8 g of modified cellulose and 0.5 g of sodium hydroxide to 80 mL of ethanol, ultrasonically treating at 30 ° C for 5 min to obtain a modified cellulose solution, adding 1.2 g of epichlorohydrin, 1.6 g of the complex and 1.3 g of gangue powder to the modified cellulose solution, stirring for 20 min, continuing to stir to form a gel, filtering, washing with deionized water, and freeze-drying at -12 ° C to obtain the loaded gangue particle aerogel.

[0027] Among them, cellulose can combine with the hydroxyl groups in the complex through hydrogen bonds. Under the action of the cross-linking agent epichlorohydrin, the formed cellulose gel has better stability and is more conducive to the complete preservation of the soil restoration agent. The catechol groups contained on the surface of the modified cellulose can combine with components such as alumina and silica in the coal gangue powder, which can promote the cross-linking degree of cellulose gel and make the coal gangue powder evenly dispersed in the cellulose gel.

[0028] Furthermore, the mass ratio of modified cellulose, sodium hydroxide, epichlorohydrin, composite and coal gangue powder is (0.7-0.9) g: (0.3-0.7) g: (1.1-1.3) g: (1.4-1.8) g: (1.2-1.4) g.

[0029] S4. Mix the loaded coal gangue particle aerogel with trace elements, add peat soil, lignite, vermiculite, and corn stalks, stir, dry, and package to obtain a soil remediation agent.

[0030] Furthermore, the trace elements are selected from boron, zinc, iron, molybdenum, copper, manganese or titanium.

[0031] Furthermore, the stirring rate is 700-900 rpm, and the stirring time is 20-30 min.

[0032] More preferably, the stirring rate is 800 rpm and the stirring time is 25 min.

[0033] Beneficial effects of the present invention:

[0034] In the technical solution of the present invention, peat soil, lignite, coal gangue, vermiculite and corn stalks are used as the basic components of the soil remediation agent. Peat soil is a natural material rich in organic matter, and has good water retention and air permeability. It also contains a large number of microorganisms and beneficial bacteria, which can promote the decomposition of organic matter in the soil, the decomposition of enzymes and the growth of microorganisms, thereby promoting the growth of plants and increasing crop yields. Lignite contains humic acid and other organic substances, which can be used as supplements of soil organic matter to increase the fertility of the soil, and can also neutralize the pH of the soil, regulate the structure and air permeability of the soil, thereby facilitating the growth of plants. Vermiculite is a silicate mineral with good water retention and air permeability, so it can be used as a soil conditioner. It can improve the structure of the soil, increase the air permeability and water retention of the soil, promote the development of plant roots, enhance the resistance of plants to stress, thereby facilitating the growth of plants. Corn stalks can increase soil organic matter and trace elements such as nitrogen, phosphorus, and potassium. They can also improve soil aggregate structure, increase soil porosity and water and fertilizer retention capacity, which is beneficial to plant growth. Combined with coal gangue powder and modified cellulose-loaded bacteria as long-term microbial agents that promote soil repair ability, the active action of microorganisms in the soil can maintain soil fertility for a long time, and prevent the soil from becoming compacted or losing fertility again due to the influence of chemical fertilizers. In addition, as the microorganisms in the soil slowly decompose the system, coal gangue also slowly flows into the soil. The active groups such as carboxyl and hydroxyl groups on the surface of coal gangue can react with minerals in the soil to increase air permeability and water retention, and prevent soil compaction. It can also neutralize the pH value in the soil to adjust the pH value of the soil and achieve a long-term recovery effect.

[0035] Dopamine hydrochloride is used to modify cellulose to prepare modified cellulose gel, and the amino groups on dopamine hydrochloride form amide bonds with the carboxyl groups on cellulose, so that the bacteria and coal gangue components have a uniform distribution effect in the system. The coal gangue powder has a uniform particle size distribution through grinding, and the contact area between the coal gangue and the soil is increased, the porosity of the soil is increased, and the air permeability and drainage performance of the soil are improved. The modified cellulose can interact with the hydroxyl groups contained on the surface of the coal gangue components through hydrogen bonds and form metal ion coordination bonds with the metal oxides in the coal gangue, so that it is evenly dispersed, thereby achieving a better recovery-promoting effect in the soil.

[0036] A foaming system mixed with a mixture and a composite bacterial strain is added to the gel system. The foaming system can make the gel form a rich system after the subsequent freeze-drying process. On the one hand, the soil remediation agent has a better effect in preventing soil compaction, and on the other hand, it can allow the bacteria and coal gangue to better enter the soil and play their role. The bacteria are encapsulated with starch. The starch-encapsulated bacteria have better stability and can reproduce and develop better in the soil. Among them, the encapsulated hydrogen-producing bacteria can better complete the dark fermentation reaction in the encapsulation environment, increase the biohydrogen content in the soil, and restore soil fertility without adding organic fertilizers.

[0037] The soil remediation agent contains a variety of composite microorganisms, including dark fermentation hydrogen-producing bacteria loaded by starch and beneficial bacteria for plant growth, as well as soil bacteria existing in peat soil. Dark fermentation hydrogen-producing bacteria are a type of microorganism that can grow and reproduce in an anaerobic environment. They can use organic matter as energy to produce hydrogen and carbon dioxide for plant use, promoting plant growth and development. The hydrogen obtained by hydrogen-producing bacteria can increase the content of biohydrogen in the soil, help promote seed germination, increase germination rate, promote seedling growth, and increase plant biomass. At the same time, biohydrogen can also improve plant photosynthesis and respiration, improve plant stress resistance, such as cold resistance, drought resistance, and salt resistance; it can inhibit the growth and reproduction of pathogens, increase the activity of antioxidant enzymes in plants, remove active oxygen free radicals, protect plant cells from oxidative damage, reduce the occurrence and spread of plant diseases, and improve plant disease resistance. In addition, biohydrogen can form complexes with metal ions to promote the absorption and utilization of metal ions such as iron, copper, and zinc by plants, and can promote the absorption and utilization of nutrients such as nitrogen and phosphorus by plants by regulating the redox balance in the plant body.

[0038] In a separate hydrogen production system, the organic acids secreted by dark fermentation bacteria will damage the acidity and alkalinity of the soil, thereby adversely affecting the soil environment. In the soil restoration agent system of the present invention, the metal oxides contained in the coal gangue in the composite can react with the organic acids in the secretions of the bacteria to form metal salts, which are then fixed in the soil. Compared with metal oxides, the metal salt form can be better utilized by plants. In addition, the loading of aerogel particles and starch can effectively prevent organic acids from flowing into the soil.

[0039] Due to the action of the bacteria in the soil remediation agent, plants have a higher absorption capacity of the trace elements therein, so the antagonism between the trace elements in the soil will become more obvious. Since the trace elements such as sulfur, iron, zinc contained in the coal gangue will inhibit the plant's absorption of trace elements such as manganese and copper, resulting in relative copper deficiency or manganese deficiency and other symptoms, the present invention additionally adjusts the amount of trace elements used in the formula to achieve the best promoting repair effect. DETAILED DESCRIPTION

[0040] The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0041] In the following examples and comparative examples, all reagents used were of analytical grade, wherein dopamine hydrochloride was provided by Shanghai Aladdin Biochemical Technology Co., Ltd., with CAS No. 62-31-7.

[0042] The component contents of the coal gangue used in the embodiments of the present invention are shown in Table 1:

[0043] Table 1

[0044]

[0045] Example 1

[0046] The composite was prepared by the following steps:

[0047] A1. Add 8.5 g corn starch to 80 mL deionized water, stir at 80 °C for 3 min until the starch is completely gelatinized, cool to room temperature, and add 1.5 × 10 9 CFU dark fermentation bacteria Clostridium difficile and 1.6 × 10 9 CFU soil beneficial bacteria nitrogen-fixing bacteria CICC20837 were stirred at 600 rpm for 3 min to allow the bacteria to fully contact with starch, and dried overnight in a light-proof environment to obtain starch-coated bacteria. Among them, the dark fermentation bacteria Clostridium butyricum, Clostridium acetobutyricum, Clostridium difficile, Clostridium tyrobutyricum, and Clostridium pasteurianum were prepared according to the conditions of 0.2×10 9 CFU: 0.3×10 9 CFU: 0.35×10 9 CFU: 0.5×10 9 CFU: 0.15×10 9 The dosage ratio of CFU is mixed;

[0048] A2. Prepare 5 g of rosin, 2 g of natural cellulose, 2.5 g of chitosan, and 1.5 g of gelatin, wash them with deionized water, dry them, and grind them into granules in a grinder. Add 6.5 g of sodium hydroxide to 20 mL of deionized water, heat it to 75°C, add 2.5 g of the granules, place it in a 100°C water bath, and stir for 2 h. During this period, add deionized water to the volume of the above reaction system to 20 mL. Cool it to 45°C, add 1.25 g of gelatin, and stir until small bubbles appear on the surface to obtain a mixture. Mix 0.7 g of starch-coated bacteria with 8 g of the mixture to obtain a composite.

[0049] Example 2

[0050] The difference between this embodiment and embodiment 1 is that the dark fermentation bacteria in this embodiment use Escherichia fergusonii; the soil beneficial bacteria use Actinomycetes Missouri CICC11008.

[0051] Comparative Example 1

[0052] The difference between this comparative example and Example 1 is that no starch is added.

[0053] Prepare 5g of rosin, 2g of natural cellulose, 2.5g of chitin, and 1.5g of gelatin, wash them with deionized water, dry them, and grind them into granules in a grinder. Add 6.5g of sodium hydroxide to 20mL of deionized water, heat it to 75℃, add 2.5g of granules, place it in a 100℃ water bath, stir for 2h, add deionized water during this period until the volume of the above reaction system is 20mL, cool it to 45℃, add 1.25g of bone glue, stir until small bubbles appear on the surface, and obtain a mixture. Mix 1.5×10 9 CFU dark fermentation bacteria Clostridium difficile and 1.6 × 10 9 CFU soil beneficial bacteria nitrogen-fixing bacteria CICC 20837 was mixed with 8g of the mixture to obtain a composite; wherein the dark fermentation bacteria Clostridium butyricum, Clostridium acetobutyricum, Clostridium difficile, Clostridium tyrobutyricum, Clostridium pasteurianum were prepared according to 0.2×10 9 CFU: 0.3×10 9 CFU: 0.35×10 9 CFU: 0.5×10 9 CFU: 0.15×10 9 The CFU dosage ratio is mixed.

[0054] Comparative Example 2

[0055] The difference between this comparative example and Example 1 is that no starch-coated bacteria are added.

[0056] Prepare 5g of rosin, 2g of natural cellulose, 2.5g of chitosan, and 1.5g of gelatin, wash them with deionized water, dry them, and grind them into granules in a grinder. Add 6.5g of sodium hydroxide to 20mL of deionized water, heat it to 75°C, add 2.5g of granules, place it in a 100°C water bath, stir for 2h, during which time add deionized water to the volume of the above reaction system to 20mL, cool it to 45°C, add 1.25g of gelatin, and stir until small bubbles appear on the surface to obtain a composite.

[0057] Example 3

[0058] The aerogel loaded with coal gangue particles is prepared by the following steps:

[0059] B1. 6.5 g of cellulose and 2 g of dopamine hydrochloride were added to 50 mL of Tris buffer having a pH of 8, stirred evenly, introduced argon gas, stirred at 50 ° C for 12 h, and the obtained solution was freeze-dried in a freeze dryer to obtain modified cellulose;

[0060] B2. Add 0.8 g of modified cellulose and 0.5 g of sodium hydroxide to 80 mL of ethanol, and ultrasonically treat at 30°C for 5 min to obtain a modified cellulose solution. Add 1.2 g of epichlorohydrin, 1.6 g of the complex and 1.3 g of coal gangue powder to the modified cellulose solution, stir for 20 min, continue stirring to form a gel, filter, wash with deionized water, and freeze-dry at -12°C to obtain an aerogel loaded with coal gangue particles.

[0061] Comparative Example 3

[0062] The difference between this comparative example and Example 3 is that the composite is replaced by the material prepared in Comparative Example 1.

[0063] Comparative Example 4

[0064] The difference between this comparative example and Example 3 is that the composite is replaced by the material prepared in Comparative Example 2.

[0065] Comparative Example 5

[0066] The difference between this comparative example and Example 3 is that the modified cellulose is replaced by cellulose.

[0067] 0.8 g of cellulose and 0.5 g of sodium hydroxide were added to 80 mL of ethanol, and ultrasonically treated at 30°C for 5 min to obtain a modified cellulose solution. 1.2 g of epichlorohydrin, 1.6 g of the complex and 1.3 g of coal gangue powder were added to the modified cellulose solution, and stirred for 20 min. Stirring was continued to form a gel, which was filtered, washed with deionized water, and freeze-dried at -12°C to obtain an aerogel loaded with coal gangue particles.

[0068] Comparative Example 6

[0069] The difference between this comparative example and Example 3 is that no coal gangue powder is added.

[0070] Example 4

[0071] A method for preparing a trace element gangue soil repair agent comprises the following steps:

[0072] 30g of coal gangue particle aerogel loaded with 0.9g of trace element boron, 1.5g of peat soil, 1g of lignite, 2g of vermiculite, and 1g of corn straw were added, stirred at a stirring rate of 800rpm and a stirring time of 25min, dried in an oven at 30°C for 10min, and packaged to obtain a soil remediation agent.

[0073] Example 5

[0074] A method for preparing a trace element gangue soil repair agent comprises the following steps:

[0075] 35 g of coal gangue particle aerogel loaded with 1.1 g of trace element zinc was mixed, and 1.7 g of peat soil, 1.2 g of lignite, 2.5 g of vermiculite, and 1.5 g of corn stalks were added. The mixture was stirred at a stirring rate of 800 rpm and a stirring time of 25 min. After drying in an oven at 30° C. for 10 min, the mixture was packaged to obtain a soil remediation agent.

[0076] Example 6

[0077] A method for preparing a trace element gangue soil repair agent comprises the following steps:

[0078] 40 g of coal gangue particle aerogel loaded with 1.3 g of trace element iron was mixed, and 1.9 g of peat soil, 1.4 g of lignite, 3 g of vermiculite, and 2 g of corn stalks were added. The mixture was stirred at a stirring rate of 800 rpm and a stirring time of 25 min. After drying in an oven at 30° C. for 10 min, the mixture was packaged to obtain a soil remediation agent.

[0079] Comparative Example 7

[0080] The difference between this comparative example and Example 5 is that the aerogel loaded with coal gangue particles is replaced by the material prepared in Comparative Example 3.

[0081] Comparative Example 8

[0082] The difference between this comparative example and Example 5 is that the aerogel loaded with coal gangue particles is replaced with the material prepared in Comparative Example 4.

[0083] Comparative Example 9

[0084] The difference between this comparative example and Example 5 is that the aerogel loaded with coal gangue particles is replaced by the material prepared in Comparative Example 5.

[0085] Comparative Example 10

[0086] The difference between this comparative example and Example 5 is that the aerogel loaded with coal gangue particles is replaced by the material prepared in Comparative Example 6.

[0087] The soil remediation agents prepared in Examples 4-6 and Comparative Examples 7-10 were tested for yield-increasing effects. Rice was used as the test crop, and the Shendao 47 and Longjing 28 varieties of rice were tested respectively. 10 m 2 Rice was planted in the test field, and the soil remediation agents prepared in Examples 4-6 and Comparative Examples 7-10 were applied respectively. The rice was harvested after 130 days, and the yield was calculated to determine the yield-increasing effect of the fertilizer. The test results are shown in Table 2 below:

[0088] Table 2

[0089]

[0090] The yield-increasing effect of the soil remediation agents prepared in Examples 4-6 and Comparative Examples 7-10 was tested. Taking cabbage planted in a greenhouse as an example, the cabbage seeds were planted in the existing soil and in the five soils sprayed with the remediation agents prepared in the examples. The experimental results are compared in Table 3 below:

[0091] Table 3

[0092]

[0093] It can be seen from Table 2 and Table 3 above that the soil remediation agents prepared in the three embodiments have better yield-increasing effects than the samples in the comparative examples. From the comparison of the yield of comparative examples 7-10 and the plant height and fresh weight of potted cabbage, the starch-coated strains have the greatest impact on crop yield, and the mixture, coal gangue powder and composite strains promote crop yield.

[0094] The data in Table 2 and Table 3 show that the soil remediation agent prepared in Examples 4-6 not only has good soil remediation performance, but also the added additives can be better dispersed in the soil system to play a remediation role. The composite strain is coated with starch and then mixed with the mixture to obtain a composite; cellulose is modified with dopamine hydrochloride to obtain modified cellulose, and the modified cellulose, the composite, coal gangue powder and the gelling agent are mixed to obtain a hydrogel, which is freeze-dried to obtain aerogel loaded with coal gangue particles; the aerogel loaded with coal gangue particles is mixed with trace elements, peat soil, lignite, vermiculite and corn stalks are added and stirred, and the soil remediation agent is obtained after drying and packaging to meet the test performance requirements, while the soil remediation agent prepared in Comparative Examples 3-5 does not meet the performance requirements, indicating that the soil remediation agent prepared by the present invention not only has good soil remediation performance, but also the added additives can be better dispersed in the soil system to play a remediation role.

[0095] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0096] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing a trace element gangue soil remediation agent, characterized in that: The following steps are involved: S1. Washing and grinding the gangue into powder to obtain gangue powder; S2. The dark fermented bacteria are mixed with beneficial soil bacteria to obtain a composite bacteria, the composite bacteria are coated with starch, and then mixed with the mixture to obtain a composite; The dark fermentation bacteria is at least one of Clostridium, Desulfovibrio, Enterobacter, and Escherichia; The beneficial soil bacteria are at least one of nitrogen-fixing bacteria, rhizobia, actinomycetes, lactic acid bacteria, yeasts, and molds; The mixture is specifically prepared by the following steps: Prepare rosin, natural cellulose, chitosan, and gelatin, wash them with deionized water, dry them, and grind them in a grinder to obtain particles; add sodium hydroxide to deionized water, heat it to 75°C, add the particles, stir them in a water bath, add deionized water until the volume of the reaction system is 20 mL, cool it to 45°C, add gelatin, stir them, and obtain a mixture; The usage ratio of rosin, natural cellulose, chitin and gelatin is (4-6):(1-3):(2-3):(1-2); S3. Modifying cellulose with dopamine hydrochloride to obtain modified cellulose, mixing the modified cellulose, the composite, gangue powder and epichlorohydrin to obtain a hydrogel, and freeze-drying to obtain a gangue particle-loaded aerogel; The modified cellulose is specifically prepared by the following steps: Add cellulose and dopamine hydrochloride to Tris buffer, stir evenly, introduce inert gas, stir at 50° C., freeze-dry the obtained solution in a freeze dryer to obtain modified cellulose; S4. The gangue particle aerogel loaded with trace elements is mixed, peat soil, lignite, vermiculite, corn stalks are added, stirred, dried and packaged to obtain a soil remediation agent; The trace elements are selected from boron, zinc, iron, molybdenum, copper, manganese or titanium.

2. The method for preparing a trace element gangue soil repair agent according to claim 1, characterized in that: The composite is prepared by the following steps: A1. Add corn starch to deionized water, stir at 80°C until the starch is completely gelatinized, cool to room temperature, add dark fermentation bacteria and soil beneficial bacteria, stir, and dry overnight in a dark environment to obtain starch-coated bacteria; A2. Mixing the starch-coated bacteria with the mixture to obtain a composite.

3. The method for preparing a trace element gangue soil repair agent according to claim 1, characterized in that: The aerogel loaded with coal gangue particles is prepared by the following steps: Modified cellulose and sodium hydroxide are added to ethanol, and ultrasonic treatment is performed to obtain a modified cellulose solution. Epichlorohydrin, a complex and coal gangue powder are added to the modified cellulose solution, and stirring is continued to form a gel. The solution is filtered, washed and freeze-dried to obtain an aerogel loaded with coal gangue particles.

4. The method for preparing a trace element gangue soil repair agent according to claim 1, characterized in that: The dosage ratio of the cellulose, dopamine hydrochloride and Tris buffer is (6-7) g: (1-3) g: (1-2) mL.

5. The method for preparing a trace element gangue soil repair agent according to claim 3, characterized in that: The mass ratio of the modified cellulose, sodium hydroxide, epichlorohydrin, the composite and coal gangue powder is (0.7-0.9) g: (0.3-0.7) g: (1.1-1.3) g: (1.4-1.8) g: (1.2-1.4) g.

6. The method for preparing a trace element gangue soil repair agent according to claim 1, characterized in that: The stirring rate is 700-900 rpm, and the stirring time is 20-30 min.

7. A trace element coal gangue soil remediation agent, characterized in that: The invention is prepared by the preparation method of the trace element gangue soil remediation agent according to any one of claims 1 to 6.

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