Biochar-based solid slow-release hydrogen compound fertilizer as well as preparation method and application thereof

Abstract

The invention discloses a biochar-based solid slow-release hydrogen compound fertilizer as well as a preparation method and application thereof, and the biochar-based solid slow-release hydrogen compound fertilizer comprises the following raw materials in parts by weight: 80-120 parts of biochar, 0.1-20 parts of a solid hydrogen release material, 20-150 parts of an adhesive and 0-70 parts of an acid-base regulator, the solid hydrogen release material comprises one or more of Mg powder, magnesium hydride, a magnesium hydrogen compound, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride and magnesium silicide; and the adhesive positions the solid hydrogen release material on the surface and in the micropores of the biochar. The charcoal-based solid slow-release hydrogen compound fertilizer disclosed by the invention has an efficient and stable hydrogen release effect, is high in hydrogen utilization efficiency, can promote soil improvement and crop growth, is wide in application range, and has popularization and promotion values.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological agriculture, and in particular to a biochar-based solid slow-release hydrogen compound fertilizer and a preparation method and application thereof. Background Art

[0002] As the cornerstone of agricultural production, soil directly affects the growth and yield of crops. Hydrogen, as an emerging biological regulatory factor, can significantly enhance the biological activity of soil by regulating the structure and function of soil communities, thereby promoting the growth of crops. Islam et al. (2023) in Microbial Biotechnology and Greening et al. (2022) in Trends in Microbiology both pointed out that the rich hydrogen-producing and hydrogen-consuming bacterial communities in the soil directly affect the ecological balance of rhizosphere microorganisms by rapidly consuming the produced hydrogen. In addition, hydrogen can also optimize soil nutrient cycles by regulating the abundance of key functional genes in soil carbon, nitrogen, and phosphorus cycles (Li et al., 2024, Plants). Obviously, hydrogen has opened up a new way to improve agricultural production efficiency.

[0003] Although hydrogen has great application potential and a broad market, its actual operation in soil improvement faces many challenges. Traditional methods such as hydrogen fumigation or hydrogen-rich water irrigation are limited by the high diffusivity and volatility of hydrogen, making it difficult to maintain an effective concentration, and additional measures such as film coating are required to prevent escape. For example, the invention CN112913372A discloses a method for improving the quality of crop seeds based on hydrogen. By using hydrogen treatment during the production process of crop seeds, the quality of crop seeds is effectively and safely improved, overcoming the defect that genetic modification can only improve a few or even a single trait, thereby avoiding possible biosafety issues. At the same time, it also overcomes the environmental pollution caused by the use of chemical mutagens in traditional breeding processes. Or use an electrolytic hydrogen water machine to "make and use" (patent publication number: CN 218353768 U), which increases the complexity and cost of the operation. Solid hydrogen material is a new type of hydrogen supply material developed in recent years. It can achieve slow release of hydrogen through hydrolysis reaction and can adjust the hydrogen supply concentration according to crop growth needs and environmental conditions. It has the advantages of high hydrogen supply density, controllable concentration and long-term slow release, which greatly simplifies the soil improvement process and improves the convenience of operation. However, solid hydrogen material is not without obstacles in the application of soil fertilizer.

[0004] Since the solid hydrogen material can achieve significant biological effects with a small amount, uniform mixing with soil becomes a problem, and the direct contact area with soil microorganisms is limited, resulting in a greatly reduced utilization efficiency of hydrogen. For this reason, it is key to explore the innovative combination of solid hydrogen materials and soil improvement media to prepare efficient slow-release hydrogen fertilizers. In the invention CN117602988A, a method for manufacturing biological organic multifunctional materials from magnesium hydrogen-inorganic carbon-agricultural organic waste is disclosed. In this method, magnesium hydrogen-inorganic carbon-agricultural organic waste is used as raw materials to produce a biological organic multifunctional material, which can be used as a basic material (matrix) for agricultural production, contaminated soil remediation, ecological remediation of polluted environment, pharmaceuticals, cosmetics manufacturing and other fields. Multifunctional materials. The invention uses inorganic carbon to adsorb magnesium hydride to increase its direct contact area with soil, but the adsorption of inorganic carbon is weak and cannot effectively delay the release of hydrogen. Therefore, the hydrogen release sustainability and stability of the multifunctional material, as well as the soil improvement effect, still need to be improved.

[0005] Biochar is a carbon material made from biomass through pyrolysis or gasification. With its porous structure and high specific surface area, it can not only enhance the binding force between soil particles, but also provide an ideal habitat for microorganisms. At the same time, it is rich in nutrients such as nitrogen, phosphorus, potassium, etc. that are essential for crops, which comprehensively improves soil fertility.

[0006] Invention CN117603703A discloses a method for manufacturing soil conditioner with magnesium hydride-biochar-biological organic matter. Magnesium hydride or a mixture of hydrogen and magnesium in a certain proportion that adheres to the surface of the micropores of biochar and enters the micropores is uniformly mixed with biological organic matter in proportion and cured for 10-90 days. During this process, ① the magnesium hydride that adheres to the surface of the micropores of biochar and enters the micropores reacts with the moisture in the biological organic matter and magnesium hydride to produce hydrogen. Hydrogen and magnesium promote the activity of the beneficial microbial flora of the biological organic matter and improve the effect of the soil conditioner product. ② The mixture of hydrogen and magnesium in a certain proportion that adheres to the surface of the micropores of biochar and enters the micropores slowly releases hydrogen and magnesium under the action of biochar and moisture, promoting the enzyme activity of the beneficial microbial flora of the biological organic matter and improving the effect of the soil conditioner product. The interaction between biochar and magnesium hydride / Mg powder in the soil conditioner of this invention is weak, which makes hydrogen escape more easily and the release is unstable, and it is impossible to achieve long-term sustained release of hydrogen; at the same time, the physical property of magnesium hydride hydrolysis and sustained release is alkaline, and the pH value cannot be adjusted to adapt to different soil characteristics.

[0007] Invention CN117337733A discloses a method for planting rice using magnesium hydrogen-bio-based charcoal-bio-organic multifunctional materials, which uses magnesium hydrogen-bio-based charcoal-bio-organic matter as raw materials to prepare magnesium hydrogen rice seedling agent, and uses the magnesium hydrogen rice seedling agent for rice seedling-field transplanting or rice field direct seeding rice planting technology; magnesium hydride is uniformly mixed with bio-based charcoal fusion and bio-organic matter at a weight ratio of 1:1-1000 to prepare magnesium hydrogen rice seedling agent. However, the material directly applies magnesium hydride, does not have the characteristics of slow release of hydrogen, and has a short hydrogen supply time; the amount of magnesium hydride used is small, and it is unevenly mixed with the soil, which easily causes problems such as excessive local alkalinity or uneven hydrogen supply points.

[0008] Therefore, how to prepare an efficient, stable and widely applicable solid hydrogen fertilizer to achieve uniformity and durability of hydrogen slow release, effectively improve hydrogen utilization efficiency, and promote soil improvement and crop growth is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0009] In view of the defects existing in the above-mentioned prior art, the present invention provides a biochar-based solid slow-release hydrogen compound fertilizer and a preparation method and application thereof. The solid hydrogen-releasing material is compounded with biochar, and the porous structure, high specific surface area and other characteristics of biochar are utilized to provide stable adhesion and protection for the solid hydrogen-releasing material bonded to the biochar, which is beneficial to exerting the slow-release effect of hydrogen and realizing the uniform and long-lasting release of hydrogen in the soil, thereby effectively improving the soil improvement effect and promoting crop growth.

[0010] In a first aspect, the present invention provides a biochar-based solid slow-release hydrogen compound fertilizer, wherein the raw materials of the biochar-based solid slow-release hydrogen compound fertilizer include, by weight:

[0011]

[0012] The solid hydrogen-releasing material comprises one or more of Mg powder, magnesium hydride, magnesium hydrogen complex, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride, and magnesium silicide;

[0013] Biochar is a carbonized product obtained by pyrolysis or gasification of organic matter (such as wood, straw, livestock and poultry manure, etc.) under anaerobic conditions. Its most notable feature is its highly porous structure, large specific surface area and abundant pores (micropores, mesopores, macropores), which give it strong adsorption properties and can effectively adsorb moisture, nutrients, heavy metals, gases and other substances. Biochar is highly stable and difficult to be decomposed by microorganisms, so it can exist in the soil for a long time and continue to play a role in soil improvement.

[0014] Solid hydrogen-releasing materials are substances that produce hydrogen through solid-state chemical reactions. Common materials include magnesium powder, magnesium hydride, magnesium-hydrogen complexes, calcium hydride, ammonia borane, etc. They usually release hydrogen slowly through hydrolysis or other chemical reactions, and provide a controllable hydrogen release rate during the reaction. Solid hydrogen-releasing materials have a high hydrogen release density and a long hydrogen release duration, and are suitable for use in agriculture to provide hydrogen to the soil. Hydrogen can regulate soil microbial communities, improve soil biological activity, and have a positive impact on crop growth.

[0015] The adhesive of the present invention is understood in a broad sense, including but not limited to commonly used organic adhesives and inorganic adhesives, and any material in the field of compound fertilizers that can bond solid hydrogen-releasing materials to biochar can be selected. The amount of the adhesive can be selected in a variety of ways depending on its type and the purpose of the compound fertilizer, preferably 80-130 parts.

[0016] The present invention stably combines biochar with solid hydrogen-releasing materials through an adhesive, and better exerts a lasting synergistic effect to achieve an ideal soil improvement effect. The porous structure and high specific surface area of ​​biochar provide a larger attachment surface for the solid hydrogen-releasing material, so that it can be evenly distributed on the surface and pores of the biochar, thereby improving the release efficiency and sustainability of hydrogen. The adsorption performance of biochar can not only help the solid hydrogen-releasing material to be evenly distributed in the soil, avoiding the premature volatilization of hydrogen, but also extend the slow release cycle of hydrogen through its stable structure, and maintain a long-term hydrogen supply effect. In addition, the acid-base regulation of biochar helps to regulate the reaction rate of the hydrogen-releasing material, making the release of hydrogen more controllable and adapting to the needs of different soil environments (such as acidic soils or saline-alkali soils). After the two are combined, not only can the biological activity of the soil be enhanced and the reproduction of beneficial microorganisms be promoted, but also the crop growth conditions can be further optimized by regulating the hydrogen concentration and microenvironment in the soil, and the yield and quality of the crop can be improved.

[0017] Preferably, the acid-base regulator is 5-50 parts, including at least one of an organic acid-base regulator and an inorganic acid-base regulator;

[0018] The organic acid-base regulator includes one or more of amino acids, citric acid, fulvic acid, humic acid and their derivatives;

[0019] The inorganic acid-base regulator includes one or more of lime, gypsum, phosphogypsum, and ferrous sulfate.

[0020] Preferably, the biochar-based solid slow-release hydrogen compound fertilizer satisfies at least one of the following:

[0021] 1) The biochar includes one or more of wood charcoal, bamboo charcoal, straw charcoal and livestock and poultry manure charcoal;

[0022] 2) the adhesive comprises an organic adhesive, and the organic adhesive comprises at least one of maltodextrin, carboxymethyl cellulose, starch, polyvinyl alcohol, polyurethane, shellac, beeswax, rosin resin, polylactic acid, polycaprolactone, and polybutylene adipate terephthalate;

[0023] 3) The adhesive comprises an inorganic adhesive, and the inorganic adhesive comprises at least one of clay, sepiolite, and silica sol;

[0024] 4) The biochar-based solid slow-release hydrogen compound fertilizer is in the form of one or more of a strip, a sheet, or a sphere.

[0025] The compound fertilizer of the present invention has a simple composition, a wide range of sources, and a variety of molding methods, so compound fertilizer products of various shapes and sizes can be prepared, including but not limited to discs with a thickness of 1mm-30cm and a diameter of 1-50cm, and strips with a thickness of 1mm-30cm and a length and width of 1cm-1m, which are suitable for soil-cultured potted plants, large-scale fields, and soilless culture substrate applications.

[0026] Preferably, the solid hydrogen-releasing material comprises Mg powder and magnesium hydride compounded in a mass ratio of 1: (0.1-10), and the compounding method is selected from at least one of the following:

[0027] 1) Premixing the Mg powder and magnesium hydride;

[0028] 2) The Mg powder and magnesium hydride are mixed with biochar respectively to form a composite;

[0029] 3) After the Mg powder is mixed with the biochar, a portion of the magnesium powder is in-situ controlled hydrogenated to form magnesium hydride for compounding.

[0030] The present invention preferably adopts the method of mixing Mg powder with biochar, and then forming magnesium hydride by in-situ controlled hydrogenation of part of the magnesium powder. This method can simply and effectively regulate the release rate and amount of hydrogen, avoid excessive volatilization of hydrogen, and thus achieve continuous and stable release of hydrogen. The porous structure of biochar provides a larger surface area, so that Mg powder and magnesium hydride can be evenly distributed, thereby optimizing the area and rate of hydrogen release. In addition, the pores of biochar form a certain physical protection for magnesium powder and magnesium hydride, and the hydrogen is released with a delay in the hydrolysis reaction, so that the overall hydrogen release process of the composite fertilizer is relatively slow, and hydrogen can be continuously supplied for a long time, enhancing the soil improvement effect and promoting crop growth.

[0031] In a second aspect, the present invention further provides a method for preparing the biochar-based solid slow-release hydrogen compound fertilizer, comprising the following steps:

[0032] Step 1: mixing a solid hydrogen-releasing material, biochar, a binder and an optional acid-base regulator according to a proportion to obtain a mixture;

[0033] Step 2: shaping the mixture obtained in step 1 into a biochar-based solid slow-release hydrogen compound fertilizer.

[0034] Preferably, the solid hydrogen-releasing material and the biochar are pre-compounded, and the step 1 comprises the following steps:

[0035] S1. Add dry biochar into a sealed container and evacuate the container;

[0036] S2, using high-pressure gas to blow the solid hydrogen-releasing material into a closed container, so that the solid hydrogen-releasing material adheres to the surface and micropores of the biochar;

[0037] S3, adding a binder and an optional acid-base regulator and mixing with the pre-compounded solid hydrogen-releasing material and biochar to obtain a mixture.

[0038] Optionally, step S2 may also be performed by stirring and mixing the solid hydrogen-releasing material and the biochar to evenly mix them to achieve pre-compounding.

[0039] Preferably, the solid hydrogen-releasing material comprises compounded Mg powder and magnesium hydride;

[0040] Step S2 includes the following compounding steps:

[0041] 2.1 Use high-pressure gas to blow Mg powder into a closed container so that the Mg powder adheres to the surface and micropores of biochar;

[0042] 2.2 Hydrogen is introduced into a sealed container, the hydrogen pressure is maintained at 0.5-10 MPa, the temperature is maintained at 200-450°C, and the insulation time is 1-24 hours. Part of the magnesium powder is controlled to hydrogenate in situ to form magnesium hydride, and magnesium-hydrogen complexes with different ratios are obtained.

[0043] Preferably, the hydrogen pressure is 0.5-1.5 MPa, the temperature is 280-320° C., the insulation time is 1-12 h, and the mass ratio of Mg to MgH2 in the magnesium-hydrogen complex is 1:(0.1-10).

[0044] Preferably, the forming in step 2 is selected from at least one of the following forming methods:

[0045] 1) adding the mixture obtained in step 1 into a mold and pressing it into shape;

[0046] 2) adding the mixture obtained in step 1 into an extruder for extrusion molding;

[0047] 3) adding the mixture obtained in step 1 and the organic solvent into a granulator, granulating and forming the granules and drying off the organic solvent.

[0048] Preferably, the forming in step 2 is performed by thermoplastic forming;

[0049] In step 1, after the thermoplastic adhesive is heated and melted, a solid hydrogen-releasing material, biochar and an optional acid-base regulator are added to obtain a thermoplastic mixture;

[0050] In step 2, the thermoplastic mixture is poured into a mold and cooled to set the shape.

[0051] The thermoplastic adhesive includes at least one of shellac, beeswax, rosin resin, polylactic acid, polycaprolactone, and polybutylene adipate terephthalate.

[0052] In a third aspect, the present invention also provides a biochar-based solid slow-release hydrogen compound fertilizer, or the biochar-based solid slow-release hydrogen compound fertilizer obtained by the preparation method, for use in soil potted plants, large-scale field cultivation or soilless culture media.

[0053] The present invention has at least the following beneficial effects:

[0054] (1) The biochar-based solid slow-release hydrogen composite fertilizer described in the present invention is obtained through adhesives and molding processes such as pressing and extrusion to obtain a composite fertilizer with controllable component ratios, diverse structures and stability, which effectively enhances the slow-release performance of hydrogen. Through these processes, the solid hydrogen material is tightly combined with the biochar, and can stably release hydrogen during long-term use, significantly improving the utilization rate of hydrogen. Compared with traditional hydrogen application methods, the composite fertilizer of the present invention is simple and convenient to manufacture, store, transport and use, and can achieve uniform distribution and sustained release of hydrogen, thereby improving the absorption efficiency of crops to hydrogen, optimizing the soil environment, and promoting the growth of crops.

[0055] (2) The biochar-based solid slow-release hydrogen compound fertilizer of the present invention has good pH value regulation ability, and can adjust the components according to the acid-base requirements of different soils to ensure that the ideal soil improvement effect can be achieved in acidified soils or saline-alkali lands. Through the alkalinity of magnesium powder or magnesium hydride reaction products, or the addition of acid-base regulators, the compound fertilizer can effectively balance the pH value of the soil, making it more suitable for crop growth, especially in environments where the soil is severely acidified or too alkaline, it can effectively improve soil conditions and promote crop nutrient absorption and root development. At the same time, combined with soilless culture technology, its scope of application is further expanded, so that the fertilizer is not only suitable for traditional soil culture, but can also be widely used in soilless culture systems in modern agriculture. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 The pH value and hydrogen concentration change curve of the sample in Example 1 in water;

[0057] Figure 2 The pH value and hydrogen concentration change curve of the sample in Example 2 in water;

[0058] Figure 3 The pH value and hydrogen concentration change curve of the sample in Example 3 in water;

[0059] Figure 4 The pH value and hydrogen concentration change curve of the sample of Example 4 in water;

[0060] Figure 5 The hydrogen concentration variation curves of the samples of Examples 3, 7 and 10 in water;

[0061] Figure 6 It is a curve diagram of hydrogen concentration variation in water of samples of Examples 3, 11 and Comparative Example 1;

[0062] Figure 7 This is a sample diagram of the biochar-based solid slow-release hydrogen compound fertilizer sheet of the present invention. DETAILED DESCRIPTION

[0063] In order to better understand the above technical solution, the above technical solution will be described in detail below in combination with the specification and specific implementation methods. 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 making creative work are within the scope of protection of the present invention.

[0064] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0065] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0066] The present invention provides a biochar-based solid slow-release hydrogen compound fertilizer, wherein the biochar-based solid slow-release hydrogen compound fertilizer is in one or more of a strip shape, a sheet shape, and a sphere shape, and is measured by weight. The raw materials of the biochar-based solid slow-release hydrogen compound fertilizer specifically include:

[0067] (1) Biochar, 80-120 parts, including one or more of wood charcoal, bamboo charcoal, straw charcoal and livestock and poultry manure charcoal; particle size 30-100 μm (about 150-500 mesh), preferably 40-50 μm (about 250-400 mesh);

[0068] (2) solid hydrogen-releasing material, 0.1-20 parts, including one or more of Mg powder, magnesium hydride, magnesium hydrogen complex, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride, and magnesium silicide;

[0069] The solid hydrogen-releasing material is preferably a magnesium-hydrogen composite, comprising Mg powder and magnesium hydride compounded in a mass ratio of 1: (0.1-10), wherein the compounding method is selected from at least one of the following:

[0070] 1) Premixing the Mg powder and magnesium hydride;

[0071] 2) The Mg powder and magnesium hydride are mixed with biochar respectively to form a composite;

[0072] 3) After the Mg powder is mixed with the biochar, a portion of the magnesium powder is in-situ controlled hydrogenated to form magnesium hydride for compounding.

[0073] (3) a binder, 20-150 parts, preferably 80-130 parts, to position the solid hydrogen-releasing material and the acid-base regulator on the surface and in the micropores of the biochar;

[0074] The adhesive comprises an organic adhesive and / or an inorganic adhesive, wherein the organic adhesive comprises at least one of maltodextrin, carboxymethyl cellulose, starch, polyvinyl alcohol, polyurethane, shellac, beeswax, rosin resin, polylactic acid, polycaprolactone, and polybutylene adipate terephthalate; the inorganic adhesive comprises at least one of clay, sepiolite, and silica sol;

[0075] (4) Acid-base regulator, 0-70 parts, preferably 5-50 parts; including at least one of organic acid-base regulator and inorganic acid-base regulator;

[0076] The organic acid-base regulator includes one or more of amino acids, citric acid, fulvic acid, humic acid and their derivatives; the inorganic acid-base regulator includes one or more of lime, gypsum, phosphogypsum and ferrous sulfate.

[0077] The method for preparing the biochar-based solid slow-release hydrogen compound fertilizer comprises the following steps:

[0078] Step 1: Mixing the solid hydrogen-releasing material, biochar, adhesive and optional acid-base regulator according to a ratio to obtain a mixture, specifically comprising the following steps:

[0079] S1. Add dry biochar into a sealed container and evacuate the container;

[0080] S2, using high-pressure gas to blow the solid hydrogen-releasing material into a closed container, so that the solid hydrogen-releasing material adheres to the surface and micropores of the biochar;

[0081] When the solid hydrogen-releasing material comprises compounded Mg powder and magnesium hydride, step S2 preferably comprises:

[0082] 2.1 Use high-pressure gas to blow Mg powder into a closed container so that the Mg powder adheres to the surface and micropores of biochar;

[0083] 2.2 Hydrogen is introduced into a sealed container, the hydrogen pressure is maintained at 0.5-10 MPa, the temperature is 200-450°C, the holding time is 1-24 hours, part of the magnesium powder is in-situ controlled hydrogenated to form magnesium hydride, and magnesium hydrogen complexes with different ratios are obtained. Preferably, the hydrogen pressure is 0.5-1.5 MPa, the temperature is 280-320°C, the holding time is 1-12 hours, and the mass ratio of Mg to MgH2 in the magnesium hydrogen complex is 1:(0.1-10).

[0084] S3, adding a binder and an optional acid-base regulator and mixing with the pre-compounded solid hydrogen-releasing material and biochar to obtain a mixture.

[0085] Step 2: forming the mixture obtained in step 1 into a biochar-based solid slow-release hydrogen compound fertilizer by at least one of the following methods:

[0086] 1) adding the mixture obtained in step 1 into a mold and pressing it into shape;

[0087] 2) adding the mixture obtained in step 1 into an extruder for extrusion molding;

[0088] 3) adding the mixture obtained in step 1 and the organic solvent into a granulator, granulating and forming the granules and drying off the organic solvent.

[0089] 4) Thermoplastic molding is adopted. In step 1, after the thermoplastic adhesive is heated and melted, a solid hydrogen-releasing material, biochar and an optional acid-base regulator are added to obtain a thermoplastic mixture; the thermoplastic adhesive includes at least one of shellac, beeswax, rosin resin, polylactic acid, polycaprolactone and polybutylene adipate terephthalate;

[0090] In step 2, the thermoplastic mixture is poured into a mold and cooled to set the shape.

[0091] Example 1

[0092] The raw materials of the sample of Example 1 include:

[0093] Bamboo charcoal 90g (particle size about 300 mesh, brand HENANLIZE), MgH2 10g, maltodextrin 100g;

[0094] Prepared by the following steps:

[0095] Step 1: Mixing MgH2 solid hydrogen-releasing material, dry biochar, and maltodextrin according to a ratio to obtain a mixture;

[0096] Step 2: Add the mixture obtained in step 1 into a tablet press, set the pressure at 30 MPa, and press the mixture into biochar-based solid slow-release hydrogen compound fertilizer samples with a thickness of 1 cm and a diameter of 2 cm. Figure 1 shown.

[0097] Example 2

[0098] The raw materials of Example 2 sample include:

[0099] Bamboo charcoal 90g, MgH2 10g, citric acid 30g, maltodextrin 100g;

[0100] Step 1: Mixing MgH2 solid hydrogen-releasing material, dry biochar, citric acid and maltodextrin according to a proportion to obtain a mixture;

[0101] Step 2: Add the mixture obtained in step 1 into a tablet press, set the pressure to 30 MPa, and press the mixture into biochar-based solid slow-release hydrogen compound fertilizer samples with a thickness of 1 cm and a diameter of 2 cm.

[0102] Example 3

[0103] The difference between Example 3 and Example 2 is that the sample raw materials are different, including:

[0104] Bamboo charcoal 90g, MgH2 10g, citric acid 50g, maltodextrin 100g.

[0105] Example 4

[0106] The difference between Example 4 and Example 2 is that the sample raw materials are different, including:

[0107] Bamboo charcoal 90g, MgH2 10g, citric acid 70g, maltodextrin 100g.

[0108] Example 5

[0109] The difference between Example 5 and Example 2 is that the sample raw materials are different, including:

[0110] 90g straw charcoal, 10g ammonia borane, 30g citric acid, 100g polyurethane.

[0111] Example 6

[0112] The difference between Example 6 and Example 2 is that the sample raw materials are different, including:

[0113] 90g bamboo charcoal, 10g Mg powder, 30g citric acid, 100g polyvinyl alcohol.

[0114] Example 7

[0115] The difference between Example 7 and Example 3 is that the preparation method is different. The sample of Example 7 is prepared by the following method:

[0116] Step 1: Mixing MgH2 solid hydrogen-releasing material, biochar, and adhesive according to a ratio to obtain a mixture, specifically comprising the following steps:

[0117] S1. Add dry biochar into a sealed container and evacuate the container;

[0118] S2, using high-pressure gas to blow MgH2 powder into a closed container, so that the MgH2 powder adheres to the surface and micropores of the biochar;

[0119] S3. Add maltodextrin and mix with MgH2 powder and biochar to obtain a mixture.

[0120] Step 2: Add the mixture obtained in step 1 into a tablet press, set the pressure to 30 MPa, and press the mixture into biochar-based solid slow-release hydrogen compound fertilizer samples with a thickness of 1 cm and a diameter of 2 cm.

[0121] Example 8

[0122] The raw materials of Example 8 include:

[0123] Bamboo charcoal 90g, Mg powder 10g, citric acid 50g, maltodextrin 100g;

[0124] The sample of Example 8 was prepared as follows:

[0125] S1. Add dry biochar into a sealed container and evacuate the container;

[0126] S2-1, using high pressure gas to blow Mg powder into a closed container, so that the Mg powder adheres to the surface and micropores of the biochar;

[0127] S2-2. Hydrogen is introduced into the sealed container, and the hydrogen pressure is maintained at 1 MPa and the temperature is maintained at 300°C. The insulation time is about 1 hour. Part of the magnesium powder is controlled to hydrogenate in situ to form magnesium hydride. About 9 g of Mg remains, and about 1.08 g of MgH2 is generated. The mass ratio of Mg:MgH2 is about 1:0.12.

[0128] S3, adding rosin resin and mixing to obtain a mixture.

[0129] Step 2: Add the mixture obtained in step 1 into a tablet press, set the pressure to 30 MPa, and press the mixture into biochar-based solid slow-release hydrogen compound fertilizer samples with a thickness of 1 cm and a diameter of 2 cm.

[0130] Example 9

[0131] The difference between Example 9 and Example 8 is that the degree of in-situ controlled hydrogenation of magnesium powder is different, and the specific difference is:

[0132] 2.2 Hydrogen is introduced into the sealed container, the hydrogen pressure is maintained at 1 MPa, the temperature is 300°C, and the insulation time is 12 h. Part of the magnesium powder is controlled to hydrogenate in situ to form magnesium hydride, with about 5.2 g Mg and 5.2 g MgH2, and the mass ratio of Mg:MgH2 is about 1:1.

[0133] Example 10

[0134] The difference between Example 10 and Example 8 is that the degree of in-situ controlled hydrogenation of magnesium powder is different, and the specific difference is:

[0135] 2.2 Hydrogen is introduced into the sealed container, the hydrogen pressure is maintained at 1 MPa, the temperature is maintained at 300°C, and the insulation time is about 24 hours. Part of the magnesium powder is controlled to hydrogenate in situ to form magnesium hydride. The remaining Mg is about 1g, and about 9.76g of MgH2 is generated. The mass ratio of Mg:MgH2 is about 1:9.76.

[0136] Embodiment 11

[0137] The raw materials of Example 11 sample include:

[0138] Rice husk charcoal 100g, calcium hydride 10g, beeswax 30g;

[0139] Embodiment 11 adopts thermoplastic molding, and the specific molding method is as follows:

[0140] Step 1: melt the beeswax at 80°C for 1 hour, add calcium hydride powder while continuously stirring mechanically; put the rice husk charcoal into a dryer and continue to vacuum for 30 minutes; immediately put it into the above mixed solution to obtain a thermoplastic mixture;

[0141] Step 2: Stir the thermoplastic mixture at 80° C. for 1 hour until it is evenly mixed, pour it into a mold, and cool it naturally to shape it, so as to obtain a biochar-based solid slow-release hydrogen compound fertilizer cultivation matrix with a thickness of 30 cm and a diameter of 50 cm.

[0142] Comparative Example 1

[0143] The difference between Comparative Example 1 and Example 1 is that only a small amount of malt extract paste is used. The raw materials of Comparative Example 1 include:

[0144] Bamboo charcoal 90g, MgH2 10g, maltodextrin 10g;

[0145] When the mixture of Comparative Example 1 was compressed in a tablet press, the compressed sample was incomplete and loose, and was easily detached, resulting in a large loss of magnesium hydride.

[0146] The main material compositions of Examples 1-11 and Comparative Example 1 are shown in Table 1.

[0147] Table 1

[0148]

[0149]

[0150] 0.5 g of each sample of Examples 1-11 and Comparative Example 1 was added into 500 ml of distilled water, and the pH value and hydrogen concentration were tested over time to obtain the following results: Figure 1-6 .

[0151] The citric acid content of Examples 1-4 is gradually increased to neutralize the alkalinity of the MgH2 reaction product. Figure 1-4 The corresponding solution pH value gradually decreases and has significant adjustability within a large range. In addition, due to the promoting effect of citric acid, the initial hydrogen production rate of Examples 2-4 is higher than that of Example 1, but due to the relatively gradual decrease in the MgH2 content in Examples 1-4, the overall hydrogen production concentration of Examples 1 and 2 in the corresponding figure is slightly higher than that of Examples 3 and 4. It can be seen that the compound fertilizer of the present invention has the adjustability of pH value and hydrogen release concentration. According to the acidity and alkalinity of the land in different regions, compound fertilizers that meet the pH requirements can be configured to provide fertility while adjusting the acidity and alkalinity of the land. And the corresponding solid hydrogen-releasing materials and dosages are configured according to the hydrogen demand of crops, and the total amount of hydrogen release and the hydrogen release rate are adjusted by adjusting the dosage of each component.

[0152] In Examples 5 and 6, relative to Example 2, the types of solid hydrogen-releasing materials, biochar, and adhesives were adjusted, respectively. When the proportions of the various materials were similar, their pH value and hydrogen concentration change curves (not shown) were similar to those of Example 2. The overall hydrogen production of Example 5 was slightly higher than that of Example 2, and the hydrogen production of Example 6 was slightly lower than that of Example 2.

[0153] In Examples 7 and 10, the solid hydrogen-releasing material is blown into the biochar by high pressure to achieve its composite with the biochar. Compared with the direct mixing in Example 3, the solid hydrogen-releasing material can better enter the micropores of the biochar, thereby improving its utilization rate and slow-release effect. Figure 5In the embodiment 7 and 10, the initial hydrogen production rate is slightly lower than that of the embodiment 3, but the whole hydrogen release process is more stable and durable. In addition, in the embodiment 10, most of the magnesium powder (about 9g) blown in at high pressure is in-situ controlled to hydrogenate to form magnesium hydride. When the same mass of solid hydrogen release material is used initially, the solid hydrogen release material obtained in the embodiment 10 and its theoretical hydrogen production are greater than that of the embodiment 7. Therefore, the total hydrogen production of the embodiment 10 in the figure is slightly higher than that of the embodiment 7. In comparison, the hydrogen production of the embodiment 8 (Mg reaction of about 1g) and the embodiment 9 (Mg reaction of about 4.8g) is slightly lower than that of the embodiment 7. According to theoretical calculations, when 10g of raw material Mg is blown in at high pressure and the amount of hydrogenation reaction is above 8.5g, the total hydrogen production can be increased relative to the embodiment 7.

[0154] In Example 11, beeswax is used to bond calcium hydride and rice husk carbon into a composite fertilizer through thermal molding. Since beeswax has a weak hydrophilicity, the initial hydrogen production rate is slightly low, but the overall hydrogen production and slow-release hydrogen effects are good. This example also provides a relatively simple molding method.

[0155] The pressed sample of Comparative Example 1 was incomplete and loose in appearance. After being added into distilled water, it reacted quickly and released hydrogen faster than Example 3 in which citric acid was added, and basically had no sustained-release effect.

[0156] The biochar-based solid slow-release hydrogen compound fertilizer provided by the present invention has efficient and stable hydrogen release effects, high hydrogen utilization efficiency, can promote soil improvement and crop growth, and is easy to shape, store and transport, and is suitable for large-scale promotion and application.

[0157] The preferred embodiments of the present invention obtained by experimenting with the above-mentioned material combinations and proportions are not exhaustive and limit the technical effects of the present invention. Once those skilled in the art know the basic creative concepts, they can make other changes and modifications to these embodiments. Therefore, the present invention is intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention.

Claims

1. A biochar-based solid slow-release hydrogen compound fertilizer, characterized in that: The raw materials of the biochar-based solid slow-release hydrogen compound fertilizer include, by weight: The solid hydrogen-releasing material comprises one or more of Mg powder, magnesium hydride, magnesium hydrogen complex, calcium hydride, potassium hydride, ammonia borane, magnesium borohydride, calcium borohydride, potassium borohydride, and magnesium silicide; The adhesive positions the solid hydrogen-releasing material and the acid-base regulator on the surface and in the micropores of the biochar.

2. The biochar-based solid slow-release hydrogen compound fertilizer according to claim 1, characterized in that: The acid-base regulator is 5-50 parts, including at least one of an organic acid-base regulator and an inorganic acid-base regulator; The organic acid-base regulator includes one or more of amino acids, citric acid, fulvic acid, humic acid and their derivatives; The inorganic acid-base regulator includes one or more of lime, gypsum, phosphogypsum, and ferrous sulfate.

3. The biochar-based solid slow-release hydrogen compound fertilizer according to claim 2, characterized in that: The biochar-based solid slow-release hydrogen compound fertilizer meets at least one of the following requirements: 1) The biochar includes one or more of wood charcoal, bamboo charcoal, straw charcoal and livestock and poultry manure charcoal; 2) the adhesive comprises an organic adhesive, and the organic adhesive comprises at least one of maltodextrin, carboxymethyl cellulose, starch, polyvinyl alcohol, polyurethane, shellac, beeswax, rosin resin, polylactic acid, polycaprolactone, and polybutylene adipate terephthalate; 3) The adhesive comprises an inorganic adhesive, and the inorganic adhesive comprises at least one of clay, sepiolite, and silica sol; 4) The biochar-based solid slow-release hydrogen compound fertilizer is in the form of one or more of a strip, a sheet, or a sphere.

4. The biochar-based solid slow-release hydrogen compound fertilizer according to any one of claims 1 to 3, characterized in that: The solid hydrogen-releasing material comprises Mg powder and magnesium hydride compounded in a mass ratio of 1: (0.1-10), and the compounding method is selected from at least one of the following: 1) Premixing the Mg powder and magnesium hydride; 2) The Mg powder and magnesium hydride are mixed with biochar respectively to form a composite; 3) After the Mg powder is mixed with the biochar, a portion of the magnesium powder is in-situ controlled hydrogenated to form magnesium hydride for compounding.

5. A method for preparing the biochar-based solid slow-release hydrogen compound fertilizer according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: mixing a solid hydrogen-releasing material, biochar, a binder and an optional acid-base regulator according to a proportion to obtain a mixture; Step 2: shaping the mixture obtained in step 1 into a biochar-based solid slow-release hydrogen compound fertilizer.

6. The preparation method according to claim 5, characterized in that: The solid hydrogen-releasing material and the biochar are pre-compounded, and the step 1 comprises the following steps: S1. Add dry biochar into a sealed container and evacuate the container; S2, using high-pressure gas to blow the solid hydrogen-releasing material into a closed container, so that the solid hydrogen-releasing material adheres to the surface and micropores of the biochar; S3, adding a binder and an optional acid-base regulator and mixing with the pre-compounded solid hydrogen-releasing material and biochar to obtain a mixture.

7. The preparation method according to claim 6, characterized in that: The solid hydrogen-releasing material comprises compounded Mg powder and magnesium hydride; Step S2 includes the following compounding steps: 2.1 Use high-pressure gas to blow Mg powder into a closed container so that the Mg powder adheres to the surface and micropores of biochar; 2.2 Hydrogen is introduced into a sealed container, the hydrogen pressure is maintained at 0.5-10 MPa, the temperature is maintained at 200-450°C, and the insulation time is 1-24 hours. Part of the magnesium powder is controlled to hydrogenate in situ to form magnesium hydride, and magnesium-hydrogen complexes with different ratios are obtained.

8. The preparation method according to any one of claims 5 to 7, characterized in that: The forming in step 2 is selected from at least one of the following forming methods: 1) adding the mixture obtained in step 1 into a mold and pressing it into shape; 2) adding the mixture obtained in step 1 into an extruder for extrusion molding; 3) adding the mixture obtained in step 1 and the organic solvent into a granulator, granulating and forming the granules and drying off the organic solvent.

9. The preparation method according to any one of claims 5 to 7, characterized in that: The molding in step 2 is thermoplastic molding; In step 1, after the thermoplastic adhesive is heated and melted, a solid hydrogen-releasing material, biochar and an optional acid-base regulator are added to obtain a thermoplastic mixture; In step 2, the thermoplastic mixture is poured into a mold and cooled to set the shape; The thermoplastic adhesive includes at least one of shellac, beeswax, rosin resin, polylactic acid, polycaprolactone, and polybutylene adipate terephthalate.

10. Use of the biochar-based solid slow-release hydrogen compound fertilizer as described in any one of claims 1 to 4, or the biochar-based solid slow-release hydrogen compound fertilizer obtained by the preparation method of the biochar-based solid slow-release hydrogen compound fertilizer as described in any one of claims 5 to 9 in soil culture potted plants, large-scale field cultivation or soilless culture substrates.

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