Humic acid coated zeolite-based nutrient slow-release fertilizer as well as preparation method and application thereof

Abstract

The invention discloses a humic acid coated zeolite-based nutrient-loaded slow-release fertilizer as well as a preparation method and application thereof. The slow-release fertilizer comprises a zeolite-based core and a humic acid polymer coating coated outside the zeolite-based core. The slow release fertilizer provided by the invention not only retains the original high-loading nutrient loading function of the nano composite zeolite material, but also endows the nano composite zeolite material with chemically stable ion exchange and adsorption functions, thereby thoroughly getting rid of the original'instant nutrient fertilizer salt core '; the slow-release fertilizer provided by the invention takes artificial humic acid as a coating material, so that the use of chemical organic materials and solvents is completely avoided. According to the invention, the conversion of the inorganic fly ash solid waste and the organic biomass solid waste from raw materials to the ecological slow-release fertilizer is realized. Meanwhile, the efficient conversion of zeolitization and humification in the chemical industrial process realizes the large-scale production of the zeolite-based material doped with the heterogeneous metal in the pore cage frame structure and the carbon-negative humic acid polymer material.

Description

[0001] This application claims priority to an earlier application filed on May 14, 2024, with the China National Intellectual Property Administration, patent application number 202410597571.1, entitled "Humic Acid-Coated Zeolite-Based Nutrient Slow-Release Fertilizer and its Preparation Method and Application". The entire contents of the earlier application are incorporated herein by reference. Technical Field

[0002] This invention belongs to the field of agricultural nano-slow-release fertilizer technology with salt resistance function, and relates to a humic acid-coated zeolite-based core nutrient slow-release fertilizer, its preparation method and application. Background Technology

[0003] To date, fertilizers remain one of the most important factors in meeting the food needs of a growing global population and ensuring food security. However, fertilizer runoff not only damages soil aggregate structure and causes soil compaction, but also pollutes the surrounding water environment, leading to a decrease in soil organic carbon content and water and fertilizer retention capacity, thus causing a decline in soil fertility and quality. Soil degradation exacerbates fertilizer runoff, resulting in surface water runoff contaminated with fertilizer nutrients, causing the runoff fertilizer to spread from farmland to rivers, lakes, and seas as eutrophic pollution; further causing environmental damage and endangering food security, among other significant problems. Fertilizer runoff and excessive application are important causes of soil degradation in arable land, desertification of arable land in arid and semi-arid regions, and the formation of polluted dead land in low-lying areas in my country. Slow-release fertilizers are products developed to address fertilizer runoff, but since the last century, the research and development of materials for coating inorganic salt compounds of fertilizer elements has reached its limit. That is, using fertilizer salt particles (cores) as controlled-release targets for slow-release coatings faces bottlenecks in material performance and cost.

[0004] The global population is projected to exceed 9.5 billion by 2050. According to the Food and Agriculture Organization of the United Nations (FAO), food production needs to increase by 70% to meet the food needs of the projected population in 2050. Due to urbanization, industrialization, desertification, and other factors, arable land on Earth is decreasing. The application of macronutrients (N, P, K, S, etc.) in the form of fertilizers remains the most reliable and effective intervention to increase agricultural yields. my country currently ranks first in the world in terms of macronutrient production capacity, output, consumption, and fertilizer loss; however, the utilization rate of nitrogen fertilizer is only 30%–35%, phosphorus fertilizer utilization is even lower at 10%–20%, and potassium fertilizer utilization is 35%–50%, while more than 50% of fertilizer nutrients are lost due to runoff.

[0005] If the dissolution rate of mineral nutrient fertilizer salts in soil water is slowed down or controlled, the fertilizer loss rate can be significantly reduced. Therefore, the concept of slow-release fertilizers emerged in the early 20th century. Slow-release fertilizers, also known as controlled / slow-release (CRFs / SRFs) fertilizers, simply reduce fertilizer loss by controlling and slowing down the dissolution rate of fertilizer salts in soil water. This is achieved by reducing the amount of fertilizer elements dissolved in water per unit time, combined with the continuous small-scale nutrient absorption during plant growth; delaying the release time of fertilizer elements in water, thereby improving the plant's absorption rate of fertilizer elements. The coating slow-release material encapsulating fertilizer salt cores has the single function of controlling and slowing down the dissolution rate of fertilizer salts. The first commercially available slow-release fertilizer with encapsulated fertilizer added sulfur, one of the plant macronutrients, as an inorganic slow-release coating agent. However, due to the insufficient wettability and coating adhesion of sulfur compounds, organic materials need to be added to enhance the sealing of the coating; furthermore, sulfur-containing coating residues in the soil can lead to an imbalance in the soil's sulfur supply, which can cause soil acidification. Subsequently, the development of slow-release fertilizers gradually adopted chemical polymer coating materials as the mainstream slow-release materials.

[0006] Because organic polymers require the use of organic solvents, and the degradation of high-molecular polymers in soil can lead to chemical residue pollution of arable land, the use of existing slow-release fertilizers in major food crop fields is limited. Although products that prevent nutrient loss through slow-release fertilizers have long existed, the global use of slow-release fertilizers has yet to exceed 1% of total fertilizer consumption. However, with the continuous increase in fertilizer use, fertilizer runoff has developed into a modern agricultural problem affecting global arable land degradation and environmental pollution.

[0007] According to the IHS Markit Handbook of Chemical Economics' "Controlled and Slow-Release Fertilizers Report," global consumption of controlled-release fertilizers (SRFs / CRFs) was approximately 1.5 million tons in 2018 and is projected to reach approximately 1.6 million tons in 2022. China is the world's largest market for the production and sale of slow-release fertilizer products, accounting for 46% of global consumption; followed by the United States (36%), Western Europe (10%), and Japan (8%). (See also: [link to relevant documentation]) Figure 1 Currently, slow-release fertilizers using organic polymers as coating materials mainly have the following problems:

[0008] (1) Organic polymers are an important source of soil microplastic pollution. The microcapsules encapsulated by polymer plastics are small in size and difficult to remove. Long-term application will lead to their accumulation in the soil, thus exacerbating the risk of soil biocompatibility. In addition, the toxic aromatic hydrocarbon solvents added during the organic polymer coating process will also remain in the soil and cause harm; long-term application of sulfur-coated fertilizers will cause soil acidification.

[0009] (2) The raw materials for organic polymer materials come from fossil energy sources such as petroleum and natural gas. Therefore, the production of polymer coating materials is equivalent to the consumption of fossil energy, which makes the cost of coated slow-release fertilizers 2 to 5 times higher than that of conventional fertilizers. They can only be used for high-value crops such as flowers and lawns, and cannot be used in field planting.

[0010] (3) Organic polymer materials, as slow-release media for coating fertilizer elements, only have the function of "slow release" or delaying the dissolution of chemical fertilizer salts, and are not beneficial to the improvement of soil quality. The large-scale degradation of organic polymers in the soil can also lead to irreversible changes in the soil microecology, affecting the long-term health of soil microbial populations.

[0011] (4) In the foreseeable future, the use of various plant macronutrient fertilizers on global agricultural land will continue to grow. If organic polymer-coated fertilizers are promoted as a solution to reduce fertilizer loss, agricultural production will significantly increase the demand for fossil energy.

[0012] To avoid fossil fuel consumption and chemical organic pollution, and to address the problem of fertilizer runoff, researchers have begun using biopolymers as raw materials to manufacture slow-release coating materials for fertilizer salt cores. Slow release is achieved through the permeation diffusion mechanism of biopolymer materials (see Appendix for the fertilizer salt release mechanism controlled by biopolymer permeation). Figure 2 The mechanism of the "nutrient diffusion model" in China is as follows;

[0013] Polymer-coated slow-release fertilizers first need to come into contact with water to dissolve the fertilizer salts: water passes through the coating and condenses on the solid granule core, subsequently dissolving some of the nutrients (fertilizer salt core). The dissolution of nutrients creates internal pressure that accumulates in the fertilizer salt core, and then slow-release diffusion occurs under the influence of osmotic pressure and the resistance of the internal expansion membrane. If the resistance generated by the membrane strength is greater than the internal expansion osmotic pressure, slow-release diffusion of nutrients into the soil water occurs. The release rate is determined by the concentration gradient pressure of the coating resistance. However, if the internal pressure exceeds the membrane resistance, a "catastrophic release" occurs, resulting in coating material rupture or coating failure; the fertilizer salt particles are instantly released into the soil water, undergoing rapid dissolution and diffusion. Figure 2 Therefore, the control of nutrient slow release and fertilizer loss depends on the performance of the coating material.

[0014] Coating materials made from biopolymer raw materials require chemical modification and alteration to improve their strength. Before chemical modification, the biopolymer raw materials need to be pretreated, for example, by processing them into intermediates such as alginate, gum, cellulose, chitin, keratin, chitin, chitosan, lignin, starch, and starch slurry: carrageenan, guar gum, frankincense, xanthan gum, etc. These pretreatments allow for further modification. For instance, chitin can be deacetylated to transform it into chitosan, which has significantly improved solubility and film-forming properties. Alternatively, crosslinking agents, compatibilizers, and plasticizers can be added to the coating solution to alter the flexibility, tensile strength, and adhesion of the polymer film. Of course, different biopolymers or mixtures and copolymers of biopolymers with synthetic polymers can also be used for physical modification: such as natural rubber and starch, lignin and ethyl cellulose, starch and lignin, starch and polyvinyl alcohol, sodium alginate and polyacrylic acid-coacrylamide, starch and polyacrylic acid-coacrylamide, chitosan and polyacrylic acid, guar gum and polyacrylamide glycolic acid, starch and polyvinyl acetate acrylate, starch and polyacrylic acid, or sodium carboxymethyl cellulose and hydroxyethyl cellulose, etc.

[0015] All of these functional modifications to materials narrow the range of biopolymer raw materials available and increase the cost of the modified materials. As the complexity of the modification increases, the additives gradually deviate the modified biopolymer from its original characteristics of being "degradable, biocompatible, and non-toxic." The outer coating of fertilizer salt cores requires high strength and permeability; once the coating material is damaged, a rapid, dissolving diffusion occurs. Therefore, the chemical modification of biopolymer coating materials cannot avoid the addition of chemicals and cannot isolate the chemical interaction between chemicals and the soil, thus making them unsuitable for use in the production of staple grains and vegetables.

[0016] In summary, biopolymer-based coating materials still primarily coat readily soluble fertilizer salts. The strength requirements for these coating materials also lead to high costs and risks associated with the use of chemicals in arable soil, making this an unsustainable technology for using "sustainable materials." Therefore, solving the problem of fertilizer runoff requires innovative slow-release material technologies. Summary of the Invention

[0017] To address the aforementioned technical problems, the present invention provides a composite sustained-release material comprising a zeolite core (which is a gel pore body of zeolite crystals bonded by a geopolymer) and a humic acid polymer coating covering the zeolite core.

[0018] According to an embodiment of the present invention, the zeolite core is a zeolite core porous body. Preferably, the particle size of the zeolite core is 0.5 mm to 10 mm, and exemplary sizes are 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, and 10 mm.

[0019] According to an embodiment of the present invention, the thickness of the humic acid polymer coating is 0.2 to 0.6 times the particle size of the zeolite-based core. Preferably, the thickness of the humic acid polymer coating is 0.1 mm to 6 mm, with exemplary thicknesses of 0.1 mm, 0.2 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm.

[0020] According to an embodiment of the present invention, the zeolite core can be loaded with macronutrients (e.g., nitrogen (N), phosphorus (P), potassium (K), sulfur (S)) and / or multiple macronutrients required by plants containing two or more of the following elements, and can be doped with various beneficial micronutrients, such as magnesium (Mg), iron (Fe), zinc (Zn), molybdenum (Mo), boron (B), selenium (Se), etc. Preferably, the above-mentioned macronutrients required by plants can be adsorbed and loaded onto the nutrient solution through the pores of the zeolite core (zeolite / geopolymer); while the specified micronutrients are doped into the zeolite lattice through a zeolite crystallization process.

[0021] According to an embodiment of the present invention, the zeolite core is a zeolite / geopolymer porous body. Preferably, the zeolite core is an aluminosilicate hydrate (inorganic crystalline phase / inorganic amorphous phase) synthesized from fly ash (also known as fly ash).

[0022] According to an embodiment of the present invention, the fly ash includes, but is not limited to, one, two or more of the following sources: coal-fired power plants, biomass power plants, coal-fired boiler heating stations, etc., such as fly ash from fly ash landfills and ultrafine powder raw materials prepared from boiler combustion residues; preferably, fly ash generated immediately by pulverized coal boilers in power plants is selected.

[0023] According to an embodiment of the present invention, the inorganic crystalline phase material within the pores is zeolite synthesized from fly ash. Preferably, the zeolite structure of the crystalline phase material within the pores is at least one of the following: FAU / Zeolite structure, FAU / Zeolite Y-type structure, FAU / Zeolite A-type, X-type, LTA / Zeolite type, etc.

[0024] According to an embodiment of the present invention, the inorganic amorphous phase material in the pores is a geopolymer (amorphous aluminum silicate hydrate) synthesized from fly ash; preferably, the inorganic amorphous phase geopolymer in the pores is a foam-type geopolymer.

[0025] Geopolymers are produced through the following reactions: (1) fly ash raw materials are decomposed into silicate monomers and aluminate monomers; (2) the monomers polymerize into aluminosilicate oligomers, which then polymerize into small geopolymer fragments or "primitive zeolite nuclei" (thermodynamically metastable and incompletely cross-linked); (3) the fragments combine into larger molecules, eventually forming an aluminosilicate inorganic polymer gel, with the crystalline phase consisting of silicates and AlO4 tetrahedra. If a foaming agent (hydrogen peroxide, sodium perborate, metallic aluminum, or silicon powder) is added to the geopolymer paste during the consolidation process, geopolymer foams with pore sizes ranging from nanometers to millimeters will be produced, with a total porosity of up to 90%.

[0026] According to an embodiment of the present invention, the zeolite-based core porous aggregates are a gel network structure of amorphous geopolymer-bonded zeolite crystals, such as... Figure 12 As shown.

[0027] According to an embodiment of the present invention, the humic acid polymer coating is a coating formed by encapsulating natural humic acid, artificial humic acid (also known as "artificial humic acid") or humic acid organic polymer (also known as "humic acid organic polymer") on a zeolite-based core.

[0028] According to an embodiment of the present invention, the artificial humic acid is an organic polymer material synthesized by the "Hydrothermal Humification" process described in the International Union for Theoretical and Applied Chemistry (IUPAC) "Top Ten Disruptive Emerging Technologies of 2021" document. For example, the artificial humic acid can be prepared according to the method disclosed in Fan Yang et al., Ahydrothermal process to turn waste biomass into artificial fulvic and humicacids for soil remediation, Science of the Total Environment, 686 (2019), 1140-1151.

[0029] According to an embodiment of the present invention, the artificial humic acid is obtained by extraction from lignite, peat, etc., and / or by hydrothermal humification (HTH) processing using biomass raw materials; preferably, lignite source extraction of mineral humic acid is performed first, and / or biomass is used as the raw material to prepare artificial humic acid through HTH (hydrothermal humification) process subsequently; the lignite source includes peat, peat lignite, and weathered lignite.

[0030] According to embodiments of the present invention, the biomass raw material refers to an organism generally formed through photosynthesis, including all biopolymers produced by life processes; preferably, it includes, but is not limited to, one, two or more of the following sources: agricultural and forestry waste, agricultural product processing by-products, livestock manure, kitchen waste, all plants, microorganisms and animals that feed on plants and microorganisms, and waste generated from the metabolism and / or production of plants, microorganisms and animals. For example, the biomass is at least one of the following: straw (excluding grains and fruits), lignocellulose from trees, agricultural and forestry waste, food waste or organic parts of municipal solid waste (OFMSW). More preferably, the biomass is wet biomass with high water content, such as wet biomass with a water content higher than 30 wt%, or wet biomass with a water content higher than 40 wt%, 50 wt%, 60 wt%, or 70 wt%, exemplarily at least one of the following: plant straw, rice husks, fallen leaves, garden pruning leaves, landscaping waste, food waste or organic parts of municipal solid waste.

[0031] According to embodiments of the present invention, the artificial humic acid contains aromatic hydrocarbons and long-chain aliphatic hydrocarbons. For example, the content of aromatic hydrocarbons is 7.00-7.50%, and the content of long-chain aliphatic hydrocarbons is 6.70-7.20%. Exemplarily, the content of aromatic hydrocarbons is 7.43%, and the content of long-chain aliphatic hydrocarbons is 7.15%.

[0032] According to embodiments of the present invention, the zeolite-based core (zeolite / geopolymer) pore body preferably has a foamed geopolymer agglomerate morphology. FAU and LTA zeolite crystals synthesized from fly ash are in powder form and are unsuitable for coating processes. Therefore, a key synthesis step of the composite material of the present invention is to convert FAU, LTA, and other types of zeolite powders into zeolite-based core (zeolite / geopolymer) pore body agglomerates suitable for humic acid polymer coating processes, while maintaining high connectivity between the cage-like pore crystals and the gel-pore amorphous structure within the pore body agglomerates.

[0033] According to an embodiment of the present invention, the mass ratio of the humic acid polymer coating to the zeolite-based core is 1:1-10:1, with exemplary ratios of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, and 1:10.

[0034] According to an embodiment of the present invention, the preparation of the zeolite-based core porous body includes using a pre-prepared zeolite crystalline phase material as one of the raw materials for synthesizing zeolite-based core porous body agglomerates to prepare zeolite-based core (zeolite / geopolymer) porous body gel agglomerates.

[0035] According to an embodiment of the present invention, the zeolite-based core porous body is a geopolymer prepared by using fly ash and pre-prepared zeolite crystalline phase materials as the main raw materials through an alkaline hydrothermal sol-gel method (i.e., a hydrothermal synthesis method to achieve a gel structure (zeolite / geopolymer porous body) of amorphous phase geopolymer bound to zeolite crystals). This process causes the metal cations (silicon and aluminum) in the geopolymer gel structure to be coordinated by oxygen bridges, forming a negatively charged ion, which is balanced by metal cations (sodium and / or potassium) in the activator; this linkage establishes long chains of spherical polymer units of zeolite crystals and aluminosilicate gel: a gel structure in which water molecules are trapped in the pores due to the dense arrangement of polymer units.

[0036] According to an embodiment of the present invention, when loading macronutrients into a zeolite-based core, the physical adsorption force and electrostatic interaction adsorption force of the substances within the pores are utilized to achieve loading of high-load macronutrients and doping of beneficial trace mineral elements.

[0037] According to an embodiment of the present invention, the preliminary process of synthesizing zeolite-based crystalline phase materials through fly ash utilizes electrostatic interaction adsorption force during zeolite crystallization to load the buffer capacity of part of the nutrient cation potassium and dope one or more specified trace mineral elements.

[0038] Coal is formed from the sedimentary evolution of ancient terrestrial plant remains. During their growth stages, these plants selectively absorbed mineral elements beneficial to their growth, such as magnesium (Mg), iron (Fe), zinc (Zn), molybdenum (Mo), boron (B), and selenium (Se) (all elements that constitute coal ash). Therefore, the zeolite crystal phase synthesized from fly ash possesses both a controllable nanoscale cage-like slow-release structure and contains oxide phases of various beneficial metal elements that have been transferred from the ash components of coal to a uniformly distributed zeolite matrix.

[0039] According to an embodiment of the present invention, the inorganic crystalline phase material of the zeolite-based core is a zeolite crystalline phase material, such as at least one of FAU / Zeolite Y type, FAU / Zeolite A type, X type, LTA / Zeolite type, etc.

[0040] According to an embodiment of the present invention, the method for preparing the zeolite crystalline phase material includes the following steps: zeolizing fly ash through a two-stage fusion (melting and hydrothermal) process to prepare the zeolite crystalline phase material.

[0041] According to an embodiment of the present invention, the melting stage process includes: mixing fly ash with alkali, heating and melting, grinding, diluting, and obtaining a crystallization precursor solution.

[0042] The alkali is selected from strong alkalis, such as sodium hydroxide or potassium hydroxide.

[0043] The heating and melting temperature can be 500-600℃, and the time can be 1-9 hours.

[0044] According to an embodiment of the present invention, the hydrothermal stage process includes: adding dopant elements (based on the analysis of trace mineral element content in fly ash), aging, and hydrothermal process to obtain crystalline composite element crystals.

[0045] According to an embodiment of the present invention, the hydrothermal stage may include repeated hydrothermal processes of N doping elements, where N is an integer equal to or greater than 1, for example, N = 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. Specifically, N can be adjusted according to the types and / or contents of trace elements required by the composite doped plant.

[0046] According to an embodiment of the present invention, doping elements are added, preferably before the start of the hydrothermal process where N>1, to introduce specified elements so that these elements uniformly form highly active catalytic sites.

[0047] According to an embodiment of the present invention, the doping element is introduced by the following dopants, including but not limited to nanoparticles of one, two or more doping elements, basic compounds and / or nuclei.

[0048] Preferably, the dopant contains trace elements that are lacking in fly ash but required by plants, as described above.

[0049] According to an embodiment of the present invention, the dopant is added to the crystallization precursor solution, but the preparation of the crystallization precursor solution differs when N = 1 and N ≥ 2:

[0050] When N=1, the crystallization precursor solution is obtained by mixing fly ash with alkali, or further mixing with dopants, heating and melting, grinding, and diluting.

[0051] When N≥2, the crystallization precursor solution is obtained by mixing and diluting the filtrate and dopants obtained after the completion of the previous hydrothermal crystallization stage, with or without the addition of alkali as needed.

[0052] According to an embodiment of the present invention, the mass ratio of the dopant to the crystallization precursor solution is 1:(1 to 5), for example 1:1, 1:2, 1:3, 1:4 or 1:5.

[0053] According to an embodiment of the present invention, the temperature of the hydrothermal process is 90–170°C, and the time is 2–48 hours.

[0054] According to one embodiment of the present invention, the method for preparing the zeolite-based core crystalline material includes the following steps:

[0055] (1) Fly ash is mixed with alkali, heated to melt, ground, and diluted to obtain the first crystallization precursor solution;

[0056] (2) The first crystallization precursor solution is subjected to a hydrothermal process and then filtered to obtain crystals and the first filtrate.

[0057] (3) The first filtrate and the dopant containing element 1, and with or without the addition of alkali as needed, are mixed and diluted to obtain a second crystallization precursor solution. The second crystallization precursor solution is filtered through a hydrothermal process to obtain crystals containing element 1 and a second filtrate.

[0058] (4) The filtrate obtained in the subsequent hydrothermal stage is processed in step (3). The dopant contains element 2, and crystals and filtrate containing element 2 are obtained. The process ends when all the elements that need to be doped are incorporated into the crystal.

[0059] Element 1 and element 2 may be the same or different, preferably different; both are selected from the above-mentioned doping elements.

[0060] Element 1 represents one, two, or more elements;

[0061] Element 2 represents one, two, or more elements.

[0062] According to an embodiment of the present invention, the zeolite crystals synthesized from fly ash have a tertiary porous structure:

[0063] The pore size of the first-order pore structure is no more than 10 nm, for example, no more than 5 nm, and preferably less than 2 nm (i.e., micropores);

[0064] The pore size of the second-order pore structure (also known as mesopore) is equal to or greater than that of the first-order pore structure, but does not exceed 50 nm;

[0065] The pore size of a third-order pore structure (also known as a macropore) is greater than 50 nm, for example, greater than 50 nm and not exceeding 500 nm, such as 200 nm.

[0066] According to an embodiment of the present invention, the sum of the specific surface areas of the zeolite-based core is 150–1500 m². 2 / g, for example 300~1200m 2 / g, such as 500-1000m 2 / g.

[0067] According to an embodiment of the present invention, the cation exchange capacity (CEC) of the zeolite core is 150-250 cmol(+) / kg.

[0068] According to an embodiment of the present invention, the pore volume ratio of the zeolite-based core is more than 50%, for example, more than 60%, such as 65-80%.

[0069] Although the pore volume ratio of FAU zeolite crystals is 50%, the theoretical value of its physical adsorption force is much smaller than 50% of the crystal volume. This is because within the primary pore framework of zeolite crystals, electrostatic adsorption forces (including the attraction between ions or molecules with opposite charges) play a dominant role, primarily driving the exchange between structural equilibrium cations and compensating ions. The zeolite lattice exhibits a preferential-inferior selection order for charge-balanced cations, meaning it shows a greater affinity for certain ions than others. Small differences in the Si / Al ratio of different zeolites constitute a fixed difference in the preferential selection sequence. Charge-balanced cations (such as Na...) + K + Ba 2+ Ca 2+ When it exchanges with other cations in aqueous solution, it does not affect the skeletal stability of aluminosilicates, but provides a buffer capacity for the dynamic equilibrium of cation diffusion in solution.

[0070] As an alternative, K can be selected as the initial charge balance cation during zeolite crystallization. + Loading is performed, meaning the charge balance ion in zeolite crystallization is K. + The buffer capacity of potassium fertilizer elements in the zeolite lattice is formed through crystallization process.

[0071] According to calculations, the cation buffer capacity of the initial charge balance of 7.5 kg of synthetic zeolite is equivalent to the cation capacity of 1 kg of 60% KCI potassium salt fertilizer K:O (3.5). When the zeolite crystallizes, the initial charge balance cation is potassium ion. The ratio of the potassium fertilizer cation buffer capacity calculated by the mass of the crystal phase material in the zeolite core pores to the cation capacity of the potassium salt fertilizer calculated by the mass is 1 / 7.5 (13.3%).

[0072] According to an embodiment of the present invention, a nutrient-saturated solution can be adsorbed through the physical adsorption force of the pores of the zeolite-based amorphous gel polymer core. In this invention, the physical adsorption force (including weak van der Waals forces) refers to the interaction force between the pore surface and water molecules. The physical adsorption force can load nutrients into the pores of the zeolite-based gel core, and the adsorbed ion solution will be released through cation equilibrium diffusion according to the ion concentration gradient in the water, following the decreasing direction of the concentration gradient within the pores.

[0073] According to an embodiment of the present invention, the zeolite-based core (zeolite / geopolymer) porous body is preferably prepared using a foam geopolymer synthesis method (with different foam generating agents); the pore density, porosity, and pore connectivity of the synthesized zeolite-based core (zeolite / geopolymer) foam porous bodies in a typical example are shown in the table below. The frequency of pore occurrence is divided into four groups according to their pore size distribution. The relative surface area of ​​pores and the pore connectivity of different pore size groups are measured using image1.52a software (NlH, USA) for geopolymers G, GM, GC, and GCM. 2 All parameters of the surface. The standard deviation is less than 10% of the mean (n=10).

[0074]

[0075] According to embodiments of the present invention, geopolymers with different pore volume / core volume ratios can be formed by using different synthesis process parameters. Therefore, it is preferable to use process parameters for synthesizing "foam porous bodies" to synthesize porous aggregates with a zeolite-based core of up to 90%. The preferred zeolite-based core "foam porous bodies" can easily load fertilizer nutrients in a large proportion (>70%) of the zeolite-based core using only physical adsorption forces.

[0076] The present invention also provides a slow-release fertilizer, wherein the above-mentioned zeolite-based core (foam) pore body is directly immersed in an environment that can adsorb fertilizer components. When applied as a slow-release fertilizer, it can be coated with a humic acid polymer coating or not, depending on the fertilizer activity.

[0077] According to an embodiment of the present invention, the loaded fertilizer active ingredient is a macronutrient element, such as N, P, K and / or S.

[0078] In another embodiment, the zeolite-based core pores of the slow-release fertilizer are loaded with one, two or more specified elements, or the zeolite-based core pores of the slow-release fertilizer are loaded with a mixture containing different specified elements.

[0079] According to an embodiment of the present invention, the diameter of the zeolite-based core (zeolite / geopolymer) pore aggregates is 0.5 mm to 10 mm.

[0080] According to an embodiment of the present invention, the mass density of the zeolite-based core (zeolite / geopolymer) pore mass aggregates is 0.5-1.0 g / cc.

[0081] According to an embodiment of the present invention, the zeolite-based core (zeolite / geopolymer) has water-holding capacity (water retention capacity >60wt%).

[0082] According to an embodiment of the present invention, the zeolite-based core (zeolite / geopolymer) has acid and alkali resistance properties and is soluble only in strong acids (low pH value).

[0083] According to an embodiment of the present invention, the macronutrient elements can be introduced by adsorbing macronutrient element solutions and / or by applying zeolite core material to animal digestive waste for adsorption and / or by using zeolite core material as a composting additive for farmyard manure to adsorb the overflowing ammonia nitrogen and hydrogen sulfide odor (utilizing the super strong ammonia nitrogen adsorption capacity of zeolite core material, i.e., adsorbing and loading nitrogen elements) and / or by mixing zeolite core material with ammonia nitrogen-enriched farmyard manure organic matter to form a nitrogen-loaded zeolite core fertilizer.

[0084] For example, the zeolite-based core material is mixed with ammonia-nitrogen-enriched farmyard manure at a ratio of 1:(1-10), such as 1:3 (in a simplified farmyard manure field composting process). A large amount of ammonia nitrogen and hydrogen sulfide volatiles will be adsorbed and loaded into the zeolite-based core material. Preferably, at the end of the composting period, the farmyard manure composting material and the added zeolite-based core material can be mixed at a ratio of (1-10):1, such as 3:1.

[0085] In one embodiment of the present invention, different macronutrients can be obtained by immersing zeolite core material in a cationic solution containing fertilizer active ingredients to obtain a zeolite core loaded with specific macronutrients, and then encapsulating it with a humic acid polymer coating to form an eco-friendly slow-release fertilizer loaded with specific nutrients.

[0086] According to an embodiment of the present invention, the composite material can be prepared by adsorbing and loading a large amount of nutrient elements (such as one or more elements such as N, P, K and / or S) onto the zeolite-based core material and then coating it with the above-mentioned humic acid coating.

[0087] The composite material of the present invention is an agricultural nutrient slow-release fertilizer coated with chemically stable porous aggregates and a highly bioactive humic acid polymer coating.

[0088] The zeolite-based core (zeolite / geopolymer) porous aggregates of this invention possess chemically stable, "permanent" water-buffered pores, exhibiting strong cation exchange capacity, high nutrient loading, and slow nutrient release. Although its water retention rate (0.5 times) is much lower than that of highly reactive organic polymer materials such as humic acid, it forms permanent adsorption pores and leachate buffer micropores in the soil environment. Therefore, it can "complement" the water retention stability of soil humic substances, preventing irreversible damage to the pore structure of the humic acid organic polymer coating during extreme drought. This maintains the reversible activity and pore structure of soil humic substances during extreme drought. Because the water retention rate of humic acid is as high as 6-7 times its mass, the stable and complementary "water-buffered" pores of the zeolite-based core porous aggregates can prevent irreversible dehydration and deactivation of soil humic substances.

[0089] This invention relates to a composite material consisting of a zeolite-based core slow-release porous body loaded with various nutrients and a humic acid coating. This composite material achieves a water retention rate of more than 6 times in the soil, resulting in a synergistic effect of superior soil salt resistance and water retention.

[0090] According to an embodiment of the present invention, the cation exchange capacity (CEC) of the composite material is 1500-3500 cmol(+) / kg.

[0091] According to an embodiment of the present invention, the mass density of the composite material is 0.8-1.8 g / cc.

[0092] According to an embodiment of the present invention, the composite material has a water retention capacity of >70 wt% in soils in arid regions.

[0093] According to an embodiment of the present invention, the zeolite-based core pores in the composite material are insoluble in water (at any pH). The zeolite-based core pores of the composite material have acid and alkali resistance properties.

[0094] According to one embodiment of the present invention, the crystallization process of alumina and silica in fly ash under the conditions of an activated solution containing potassium cations can form potassium-containing zeolite with charge-balanced potassium ion exchange buffer capacity. In the subsequent sol-gel process of geopolymer bonding and binding of zeolite powder, the potassium-containing zeolite will be added as a crystalline material to the geopolymer polymerization process of the amorphous gel structure. Preferably, potassium zeolite crystals are added to the aggregates of zeolite-based "foam porous bodies" to form a storage buffer containing potassium ion exchange. When the zeolite-based core porous body adsorbs and loads various fertilizer elements, it is not affected by the potassium ion buffer storage capacity, but only by the porosity and pore connectivity to adsorb and load the ion solution.

[0095] Nitrogen fertilizers are widely used in all crops and planting systems, but their utilization efficiency is only 30-40%. The outstanding performance of zeolite-based core porous bodies lies in their high porosity and high pore connectivity, especially the enhanced nitrogen capture, storage, and release capabilities of foam-like porous bodies. Zeolite-based core porous bodies can adsorb nutrient molecules under relatively low pressure; and after the porous bodies are saturated with adsorption, encapsulation with humic acid organic polymers yields slow-release fertilizers with ideal loading capacity. When the saturated adsorption ionic solution is a nitrogen fertilizer element solution; preferably, urea, a highly water-soluble nitrogen fertilizer, is selected, melted at 132°C, and adsorbed into the dry zeolite-based core porous body. After adsorption loading, a humic acid polymer coating is used to physically encapsulate the saturated pores of the zeolite-based core material, resulting in a slow-release nitrogen fertilizer with ultra-high loading capacity.

[0096] The highly interconnected pores of zeolite-based cores can load ammonia nitrogen into the pores through the adsorption of animal digestive waste. This allows the zeolite-based core material to effectively remove unpleasant odors from cattle pens, stables, and pigsties by adsorbing and loading animal manure. As an excellent adsorbent for nitrates, the zeolite core adsorbs and retains a large amount of ammonium ions, significantly reducing the leaching of nitrates and ammonium salts. Consequently, the zeolite-based core material loaded with animal manure can improve nitrogen use efficiency by reducing the activity of soil urease. Furthermore, when the zeolite-based core material with a large adsorption of ammonia nitrogen is combined with humic acid encapsulation, the effect of delayed nutrient release can be enhanced, reducing the frequency of fertilization in farmland.

[0097] Humic acid-coated nitrogen-adsorbing zeolite-based materials in soil can also automatically combine with rock phosphates to form cation exchange fertilizers: namely, Ca in the soil environment. 2+ The cage-like structure that will be exchanged into the zeolite-based core phase corresponds to the plant's need to absorb soil nutrient cations in response to growth: namely NH4. + or K + They will be removed from the cage. This will increase the solubility of rock phosphates in the soil. Experiments show that ammonium-containing zeolite-based materials also increase the solubility of animal bone ash phosphate minerals, promoting the dissolution of rock phosphates in all types of soil.

[0098] According to an embodiment of the present invention, one, two or more inorganic macronutrients, such as nitrogen, phosphorus, potassium or sulfur, can be specified for adsorption loading as needed; in conjunction with another embodiment of the present invention, namely the crystallization process prepared by zeolite core, the charge-balancing cation element "potassium" can be preferentially loaded.

[0099] According to an embodiment of the present invention, a novel slow-release composite material loaded with potassium and nitrogen nutrients can replace macronutrient (N, P, K) fertilizers, forming a highly efficient slow-release fertilizer that can activate phosphate fertilizer and resist salinity and retain water. This is because potassium is present in the soil along with... +and NH4 + The release of other ions in the soil (such as Ca) 2+ Na + The charge will be exchanged into the zeolite lattice to maintain the neutrality of the lattice balance charge. 2+ The process involves removing insoluble calcium phosphate from the soil system and replacing it with soluble potassium phosphate and ammonium phosphate, providing a more balanced supply of potassium and ammonium phosphate for plant use. Furthermore, the Na+ ions in the soil are exchanged into the zeolite lattice to become charge-balanced cations, which will also reduce Na+ ions in the soil. + Therefore, K + With NH4 + The novel slow-release composite material with dual loads will provide the soil with a water-retaining and salt-resistant fertilizer that provides more balanced nutrients.

[0100] According to one embodiment of the present invention, all macronutrient elements can be loaded during the preparation of the composite material. The composite material loaded with various macronutrient elements and combined with a humic acid polymer coating can completely replace all commercial fertilizers for plant macronutrients.

[0101] The present invention also provides a method for preparing the above-mentioned composite material, comprising coating humic acid onto a zeolite matrix core to prepare the composite material.

[0102] According to an embodiment of the present invention, the coating method can be one of "impregnation method, coating method or fluidized bed coating method".

[0103] According to an exemplary embodiment of the present invention, the impregnation method includes immersing a zeolite-based core in a humic acid solution to prepare the composite material.

[0104] According to an exemplary embodiment of the present invention, the coating method includes spraying a humic acid solution onto a zeolite-based core to prepare the composite material. For example, the spraying can be performed using a spray nozzle.

[0105] According to an exemplary embodiment of the present invention, the fluidized bed coating method includes spraying a humic acid solution onto a zeolite-based core in a fluidized bed to prepare the composite material. For example, the spraying can be performed using a spray nozzle.

[0106] The present invention also provides the application of the above-mentioned composite material as a slow-release medium material, preferably as a slow-release medium material for agricultural use.

[0107] In one embodiment, the composite material serves as a slow-release medium for macronutrient elements (e.g., N, P, K, and / or S).

[0108] In one embodiment, the composite material serves as a slow-release medium for herbicides.

[0109] The present invention also provides a slow-release fertilizer comprising the above-mentioned composite material, wherein the nanocomposite zeolite material in the composite material serves as a carrier for the active ingredients of the fertilizer.

[0110] According to an embodiment of the present invention, the active ingredient of the fertilizer is a macronutrient element, such as N, P, K and / or S.

[0111] In another embodiment, the composite material in the slow-release fertilizer contains one, two or more specified elements.

[0112] In another embodiment, the composite material in the slow-release fertilizer is a mixture of composite materials containing different specified elements.

[0113] In another embodiment, the composite material in the slow-release fertilizer is a mixture of composite materials that do not contain the specified element and those that contain at least one specified element.

[0114] According to an embodiment of the present invention, the slow-release fertilizer is obtained by immersing the composite material in a cationic solution containing fertilizer active ingredients;

[0115] Preferably, the cation containing the fertilizer active ingredient is provided by compounds such as ammonium nitrate, potassium nitrate, potassium phosphate, synthetic ammonia, urea, and / or sodium nitrate;

[0116] Preferably, the mass ratio of the composite material to the compound containing the fertilizer active ingredient cation is (3-10):1, for example, 7:1.

[0117] This slow-release fertilizer can completely replace macronutrient (N, P, K, S) chemicals, namely commercial fertilizers in the form of potassium nitrate, ammonium nitrate, potassium phosphate, synthetic ammonia, urea, or sodium nitrate.

[0118] According to an embodiment of the present invention, the structure (integral structure and pore structure) and specific surface area of ​​the slow-release fertilizer are substantially consistent with those of the composite material.

[0119] According to an embodiment of the present invention, the slow-release fertilizer can be a solid-liquid mixture fertilizer or a solid fertilizer.

[0120] According to one embodiment of the present invention, the macronutrient elements are loaded during the preparation process of the nanocomposite zeolite material. Preferably, the macronutrient elements are active ingredients of chemical fertilizers, such as N, P, K and / or S elements.

[0121] In one exemplary embodiment of the present invention, the preferred macronutrient element to be loaded is potassium (K). For example, the macronutrient element K is loaded in the form of a potassium salt during the preparation of the nanocomposite zeolite material.

[0122] In one embodiment of the present invention, the macronutrient elements are obtained by immersing nanocomposite zeolite materials in a cationic solution containing fertilizer active ingredients.

[0123] Composite materials loaded with various macronutrient elements can completely replace macronutrient (N, P, K, S) chemicals, namely commercial fertilizers in the form of potassium nitrate, ammonium nitrate, potassium phosphate, synthetic ammonia, urea, or sodium nitrate.

[0124] Preferably, the cation containing fertilizer active ingredients is provided by compounds such as ammonium nitrate, potassium nitrate, potassium phosphate, synthetic ammonia, urea, and / or sodium nitrate; preferably, the mass ratio of the nanocomposite zeolite material to the compound providing the cation containing fertilizer active ingredients is (3-10):1, for example, 7:1.

[0125] According to an embodiment of the present invention, one, two or more inorganic macronutrients, such as nitrogen, phosphorus, potassium or sulfur, can be specified as needed for loading macronutrients; in one embodiment of the present invention, the macronutrient element preferentially loaded in the nanocomposite zeolite material is "potassium".

[0126] According to an embodiment of the present invention, the nanocomposite zeolite material is loaded with macronutrient elements (such as one or more of N, P, K and / or S) and then coated with the above-mentioned humic acid to prepare the composite material.

[0127] Nitrogen fertilizers are widely used in all crops and planting systems, but their utilization efficiency is well known to be only 30-40%. The outstanding properties of nanocomposite zeolite materials are their enhanced nitrogen capture, storage, and release capabilities, as well as their ability to adsorb molecules under relatively low pressure. Furthermore, the adsorption capacity of nanocomposite zeolite materials is even better when humic acid organic polymers are present within the inherent large pores of the zeolite structure. Therefore, applying nanocomposite zeolite materials to animal digestive waste to load ammonia nitrogen can effectively remove unpleasant odors from cattle pens, stables, and pigsties, while simultaneously achieving the adsorption and collection of animal manure by slow-release fertilizers (reducing the amount of synthetic ammonium, urea, and other chemicals used). As a good adsorbent for nitrates, nanocomposite zeolite materials adsorb and retain large amounts of ammonium ions, significantly reducing the leaching of nitrates and ammonium salts into the environment. Consequently, slow-release fertilizers loaded with animal manure can improve nitrogen use efficiency in paddy fields by reducing soil urease activity. Furthermore, when nanocomposite zeolite materials that adsorb large amounts of ammonia nitrogen are combined with humic acid materials loaded with macronutrients, effective management of phosphorus in farmland soil can be achieved. This is because the humic acid-zeolite composite material combines with rock phosphates in the soil to form cation exchange fertilizers: namely, Ca in the soil environment... 2+The cations will be exchanged into the cage structure of the nanocomposite zeolite material, corresponding to the plant's need to absorb soil nutrient cations in response to growth: namely NH4. + or K + They will be removed from the cage. This will increase the solubility of rock phosphates in the soil. Numerous experiments have shown that ammonium-containing zeolite-based materials also increase the solubility of animal bone ash phosphate minerals, promoting the dissolution of rock phosphates in all types of soil.

[0128] The present invention also provides a slow-release herbicide comprising the above-mentioned composite material and the herbicide.

[0129] This invention also provides applications of the aforementioned slow-release fertilizers or slow-release herbicides in soil and / or agriculture. For example, they can be used as soil fertilizers, to promote the ecological balance of soil microorganisms and soil animals, to promote the degradation or inactivation of toxic substances in the soil, to improve soil pH, as plant fertilizers, to promote plant growth, and for plant irrigation. For example, slow-release fertilizers containing macronutrient cations have a stoichiometric fertility at least twice the stoichiometric fertility of the same macronutrient chemical cation.

[0130] According to an embodiment of the present invention, the slow-release fertilizer is used as a soil fertilizer and / or plant fertilizer.

[0131] The present invention also provides a soil fertilizer containing the above-mentioned composite material. The soil fertilizer may be a liquid-solid mixture or a solid fertilizer.

[0132] The present invention also provides a method for preparing the above-mentioned soil fertilizer, comprising preparing it from raw materials containing the above-mentioned composite material.

[0133] The present invention also provides a soil conditioner comprising the above-mentioned composite material. The soil conditioner may be a liquid-solid mixture conditioner or a solid conditioner.

[0134] In some implementations, the soil conditioner is used to adjust soil physical properties, such as increasing soil water holding capacity and reducing soil water salinity.

[0135] In some implementations, the soil conditioner is used to remediate contaminated soil. In some soils contaminated with heavy metals or radioactive materials, composite materials doped with special elements can be used to remediate radioactive contamination.

[0136] The present invention also provides a method for preparing the above-mentioned soil conditioner, comprising preparing it from raw materials containing the above-mentioned composite material.

[0137] The present invention also provides a plant fertilizer containing the aforementioned composite material. The plant fertilizer may be a liquid-solid mixture or a solid fertilizer.

[0138] The present invention also provides a method for preparing the above-mentioned plant fertilizer, comprising preparing the plant fertilizer from raw materials containing the above-mentioned composite material.

[0139] The present invention also provides a plant growth agent containing the above-mentioned composite material.

[0140] The present invention also provides a method for preparing the above-mentioned plant growth agent, comprising preparing the plant growth agent from raw materials containing the above-mentioned composite material.

[0141] The present invention also provides the application of the above-mentioned composite material in wastewater treatment, such as removing ammonia and / or heavy metal ions from wastewater.

[0142] The present invention also provides a wastewater treatment agent containing the above-mentioned composite material.

[0143] All embodiments of the present invention can improve the physical water retention capacity of soil and improve the water-saving aggregate structure of soil. This is because (i) the high connectivity and high porosity of the zeolite-based core material can hold more than 70% of its weight in water, and the process of repeated evaporation or reabsorption of water molecules does not damage the porous gel structure of the material's water storage buffer, forming numerous permanent micro "pools" in the soil, promoting the lateral diffusion of soil water in the root zone during irrigation, which helps to maintain rapid rewetting of the root soil and maintain long-term stable water-saving irrigation. (ii) Humic acid coating of the zeolite-based material significantly improves the water holding and retention potential, significantly improves the storage and activation capacity of macronutrient elements such as N, P, and K, and significantly reduces nutrient loss.

[0144] All embodiments of the present invention leave humic acid-coated zeolite-based core composite material in the soil, thereby creating a healthy soil micro-ecology and significantly promoting the increase of soil organic carbon. Therefore, it is an ecological slow-release fertilizer for long-term improvement of soil quality.

[0145] The beneficial effects of this invention:

[0146] (1) The ecological slow-release fertilizer of the present invention uses zeolite-based core (zeolite / geopolymer) porous material synthesized from fly ash as raw material, which retains the high nutrient loading function and endows the (zeolite / geopolymer) porous slow-release structure with high nutrient loading, completely eliminating the risk of rapid dissolution of "nutrient fertilizer salt core" in the soil; the present invention also uses artificial humic acid synthesized from biomass as raw material to replace chemical organic polymer as coating, completely eliminating the pollution risk of chemical organic materials and organic solvents.

[0147] (2) This invention is based on the "fly ash zeolite / geopolymer synthesis process" and the "hydrothermal humification process," using inorganic fly ash solid waste and organic biomass solid waste as raw materials to produce a novel multifunctional composite material with a "high-load nutrient slow-release core" encapsulated in a humic acid polymer coating, thus completing the regeneration and transformation of solid waste raw materials into advanced ecological slow-release materials. In patent application No. 2024102442310, the inventors proposed a combined process of "fly ash zeoliteification" and "biomass humification," which can realize the low-cost manufacturing of zeolite-based core crystalline phase materials with "porous cage structure doped with heterogeneous metals" and artificial humic acid polymer materials.

[0148] (3) Unlike the “controlled / slow-release fertilizer” and “green slow-release fertilizer” products currently on the market, the chemical fertilizer nutrients loaded in the ecological slow-release fertilizer of the present invention are under the control of the porous structure of the zeolite-based slow-release core. The cations of mineral nutrients diffuse and release from the inside to the outside in a gradient according to the ion concentration balance mechanism, which is not affected by whether the humic acid coating on the outside of the “core” is “damaged”. At the same time, the humic acid polymer coating encapsulated on the outside of the zeolite slow-release core loaded with nutrients is a colloidal coating with strong ion exchange performance in the soil. Therefore, it can be used as an active substance for soil health restoration for a long time. It can strongly bind water, ions and hydrophobic molecules in the soil, ensuring the activity of microorganisms at the interface of mineral nutrients. At the same time, it can also provide a stable environmental pH value and long-term redox buffer for the reproduction of microorganisms and fungi.

[0149] (4) The ecological slow-release fertilizer uses a porous crystal core loaded with nutrients based on artificial zeolite to replace the granular core of chemical fertilizer quick-dissolving salt. The core of the zeolite structure itself is a slow-release material, so there is no performance requirement for the resistance strength of the coating material similar to that of quick-dissolving salt. The high-load zeolite-based "core" of the present invention can be coated and coated with "rough" and inexpensive biopolymers. The resulting colloidal coating is coated on the outside of the nanocomposite zeolite-based core as a barrier for nutrient diffusion. It can also further control the release rate of nutrient NPK and avoid the pollution of soil by chemical organic materials and organic solvents.

[0150] (5) The beneficial effects of slow-release fertilizer on soil pH and soil microbial biomass are as follows:

[0151] Soil pH is a crucial parameter for plant growth, as deviations from the optimal pH level affect nutrient availability. Most plant root nutrients function optimally in soils with a pH of 5.5-7. Humic acid coating materials, containing 6-7 times their own weight in water, can improve plant survival rates under drought conditions. Furthermore, humic acid materials contain a large number of -carboxyl and -COO groups. - It can react with OH in the soil solution - and H +The reaction occurs, providing a buffer for the soil near the roots and stabilizing the pH value to approximately 7. Humic acid can stimulate soil microbial activity, promoting the completion of many important biological processes mediated by soil microorganisms, such as nutrient cycling and the degradation of pesticides and pollutants. Soil microorganisms also require biopolymer organic carbon for their own energy and cell synthesis. To date, few studies have used humic acid as a coating for zeolite-based porous crystalline materials. Humic acid coatings can alleviate the nutrient stress often experienced when using chemical organic coating materials on soil microorganisms.

[0152] (6) The beneficial effects of ecological slow-release fertilizer on activating soil-deposited phosphate fertilizer and on nutrient bioavailability are as follows:

[0153] Humic acid polymer colloidal coatings, acting as encapsulation layers for zeolite-based crystal particles, create contact channels between the soil environment and the zeolite-based core porous medium, connecting nutrients through the amphiphilic humic acid coating. This stimulates the interaction between soil water and mineral nutrients within the humic acid colloids, resulting in efficient utilization of high-capacity macronutrients through slow colloidal diffusion. This is particularly beneficial when K is loaded using two adsorption mechanisms. + and NH4 + Ion-loaded zeolite is a slow-release fertilizer that activates deposited phosphate fertilizer in the soil and provides high salt resistance. Its functions include: (I) K + and NH4 + Ions diffuse from zeolite into the soil water, along with K + and NH4 + As plants detach from soil water, zeolite diffuses and releases more superimposed and complex ions, maintaining a dynamic balance of ion concentration between the soil and zeolite. At any given time, the nutrient concentration in the solution is low, resulting in minimal nutrient loss during leaching and maintaining a balanced soil concentration, thus greatly improving fertilization efficiency. (II) The release of nutrient cations depends solely on the cation concentration after plant absorption, increasing with K... + and NH4 + The release of other ions in the soil (such as Ca) 2+ Na + The charge will be exchanged into the zeolite lattice to maintain the neutrality of the lattice balance charge. This is achieved through Ca... 2+ Removal from the soil system resulted in the replacement of insoluble calcium phosphate with soluble potassium phosphate and ammonium phosphate, making them more readily available to plants. The humic acid coating also significantly increased phosphorus availability in calcareous soils, enhancing the diffusion rate of soluble phosphorus. Humic acid also significantly induced greater nitrogen uptake by plants. (III) Soil Na + The Na+ cations exchanged into the zeolite lattice become charge-balanced cations, reducing soil salinization. + The potassium and nitrogen dual-loaded zeolite-based slow-release core has the functions of activating phosphate fertilizer and highly resisting salt.

[0154] (7) The beneficial effects of slow-release fertilizer on soil physical properties, especially water retention capacity, are as follows:

[0155] Humic acid exhibits outstanding soil water retention properties, particularly effective in improving the water retention capacity of sandy soils. The high water retention rate and capacity of humic acid in soil are due to the characteristics of its hydrophilic groups and network structure at the polymer scale, primarily the water-retention capacity formed by strong hydrogen bonds between water molecules and these biopolymers. The water retention capacity, strong ion exchange capacity, and ability to stimulate soil microbial activity of humic acid polymers give them enormous potential for soil improvement. Using humic acid polymer colloids as coating materials for zeolite-based cores creates conditions for advanced agricultural practices that continuously increase soil organic carbon annually. Due to the role of humic acid coating materials in controlling nutrient release and soil stabilization, they can have a positive long-term impact on plant growth.

[0156] (8) Ecological slow-release fertilizer promotes a balanced supply of nutrients in the soil, which has the following beneficial effects on plant growth:

[0157] Coal is formed from the sedimentary evolution of ancient terrestrial plant remains. During their growth stages, these plants selectively absorb trace mineral elements beneficial to their growth. Slow-release cores synthesized from fly ash inherit these beneficial trace mineral elements, allowing them to be reintroduced into the soil for regeneration and recycling, thus creating a healthy soil micro-ecology that promotes a balanced supply of nutrients. Humic acid not only stimulates plant growth but also has antiviral effects. Adding humic acid to the soil can immediately promote the activity of many beneficial microorganisms, which act as the "immune system" against plant diseases. Pathogens are toxic, and many trace metals act as catalysts for microbial degradation of toxins, serving as essential "vitamins" for maintaining the healthy activity of beneficial microorganisms in the defense and degradation of toxins. Humic acid, in the soil ecosystem, simultaneously plays a fundamental buffering role in the stability of the complex life processes by acting as an antioxidant, preventing free radicals, and promoting the activity of plant and animal cells. The affinity of humic acid polymers for viral receptors in the soil can block virus-specific receptors and induce the immune system to fight pathogens.

[0158] (9) The beneficial effects of slow-release fertilizer on increasing soil organic carbon are as follows:

[0159] A healthy and fertile topsoil (30cm) needs to contain 6%–8% humic acid (above 10% will negatively impact soil fertility). When the soil organic carbon content is below 8%, there is a positive correlation between the percentage of organic carbon and plant growth. The natural humification process of soil cannot balance the consumption of soil organic carbon caused by agricultural cultivation; the global average organic carbon content in the topsoil of arable land has degraded to less than 2%. In addition to providing a short-term effect of high-load slow-release fertilizer elements, the ecological slow-release fertilizer of this invention can also improve the soil microecology and amplify the increase in soil organic carbon (the increase in soil organic carbon can reach 70 times the amount of artificial humic acid produced from biomass waste when added to the soil). Under conventional arable land planting conditions, the “arable land carbon management action”, which simply replaces chemical fertilizers with ecological slow-release fertilizers in a 1:1 ratio, can form an external input of soil organic carbon, becoming a lever to improve soil fertility and stimulate plant biomass; the conventional application of ecological slow-release fertilizers (replacing conventional chemical fertilizers) can produce a multiplier effect of 70 times the external input of “negative carbon”.

[0160] Global food and nutrition security is determined by three main factors closely related to soil: water resources, soil health, and balanced supply of plant nutrients. Therefore, the high water retention capacity, high nutrient loading capacity, and balanced nutrient supply capabilities of novel ecological slow-release fertilizers can immediately prevent fertilizer runoff and achieve the effect of "high-capacity nutrient slow release." They can also gradually achieve long-term goals such as "increasing soil organic carbon," "balanced soil nutrient supply," "maintaining and improving soil structure," and "controlling soil pests and diseases."

[0161] Under good agricultural practices, if ecological slow-release fertilizers are used year by year and season by season to replace chemical fertilizers according to traditional fertilization habits: the various excellent functions of ecological slow-release fertilizers in arable soil, such as full and balanced "nutrient cycling", active biomass "carbon conversion", continuous "soil structure maintenance" and benign "pest and disease control", will gradually increase the increase of arable soil organic carbon year by year. This will promote the small annual increase in soil organic carbon concentration (such as an increase of 0.4%) that most climatologists and scientists firmly believe can promote the improvement of global agricultural arable soil fertility and ensure food security; at the same time, it can help mitigate (or cure) the climate crisis. Attached Figure Description

[0162] Figure 1 This is a statistical chart showing the total consumption of controlled-release fertilizers in 2018.

[0163] Figure 2 This is a schematic diagram illustrating the release mechanism of nutrients through the polymer coating when in contact with soil water.

[0164] Figure 3 It is a porous cage-like crystal structure of nanocomposite zeolite material.

[0165] Figure 4 This is a schematic diagram of the structure of different geopolymers based on the atomic ratio Si:A1.

[0166] Figure 5 This is a diagram of the geological polymerization reaction mechanism.

[0167] Figure 6 This is a diagram illustrating the adsorption mechanism of methylene blue dye on geopolymer-zeolite composite materials.

[0168] Figure 7 A schematic diagram of the mechanism by which coal-fly ash powder forms zeolite-geopolymer pores.

[0169] Figure 8 This is a schematic diagram of the structure of the humic acid-encapsulated zeolite-based core composite material of the present invention.

[0170] Figure 9 This is a schematic diagram of the ion exchange process of CFA zeolite in soil.

[0171] Figure 10 This is a process flow diagram for preparing the humic acid-encapsulated zeolite-based core composite material of the present invention.

[0172] Figure 11 This is a schematic diagram of the preparation process of the humic acid-encapsulated zeolite-based core composite material of the present invention.

[0173] Figure 12 This is a diagram showing the morphological appearance of zeolite-based core porous aggregates.

[0174] Figure 13 A process flow diagram for introducing doping elements.

[0175] Figure 14 The morphological appearance of the zeolite-based core after physical adsorption of nutrient solution.

[0176] Figure 15 This is a diagram showing the morphological appearance of humic acid compound ecological slow-release fertilizer.

[0177] Figure 16 This is a comparison chart of plant growth. Detailed Implementation

[0178] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0179] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0180] Example 1

[0181] A composite material comprising a zeolite-based core (or zeolite / geopolymer material, zeolite-based core porous aggregates) and a humic acid polymer coating covering the zeolite-based core.

[0182] Main chemicals: Sodium hydroxide, potassium hydroxide, hydrogen peroxide, fertilizer elements, etc.

[0183] The particle size of the zeolite-based core porous aggregates is 2 mm, and the thickness of the humic acid polymer coating is 1 mm.

[0184] Zeolite-based core porous body (without added nutrients); contains the following trace mineral elements: magnesium (Mg), iron (Fe), zinc (Zn), molybdenum (Mo), boron (B), and selenium (Se).

[0185] The porosity / volume ratio was 0.583, and the ammonia nitrogen solution loading / volume ratio was 0.76.

[0186] The artificial humic acid contains aromatic hydrocarbons and long-chain aliphatic hydrocarbons. The aromatic hydrocarbon content is 7.43%, and the long-chain aliphatic hydrocarbon content is 7.15%. The hydrothermal humification (HTH) is performed according to the method disclosed in Fan Yang et al., A hydrothermal process to turn waste biomass into artificial fulvic and humic acids for soil remediation, Science of the Total Environment, 686 (2019), 1140-1151. In this embodiment, the artificial humic acid is prepared by mixing mineral humic acid extracted from lignite, peat coal, etc., with two humic acids prepared from biomass through the aforementioned disclosed HTH process. The cation exchange capacity (CEC) of the composite material is 1500-3500 cmol(+) / kg.

[0187] In this embodiment, the mass density of the composite material is 1.2-2.2 g / cc.

[0188] The method for preparing the above-mentioned composite material includes immersing a zeolite-based core in a humic acid solution to obtain the composite material.

[0189] Example 2

[0190] The fly ash produced immediately by the pulverized coal boiler at Hainan Ledong Guoneng Power Plant was selected.

[0191] The zeolite synthesis process of fly ash involves two stages of two-stage fusion (melting and hydrothermal). The melting stage includes mixing fly ash with alkali, heating and melting, grinding, and diluting to obtain a crystallization precursor solution.

[0192] The base is selected from strong bases, such as sodium hydroxide.

[0193] The heating and melting temperature can be 500-600℃, and the time can be 1-9 hours.

[0194] In this embodiment of the invention, the dopant element is introduced through dopant, including but not limited to nanoparticles, alkaline substances, and / or nuclei containing one, two, or more dopant elements. The dopant element is a specified trace element required by the plant; in this embodiment, it is a cerium dopant or a lanthanum dopant. The dopant is added to the crystallization precursor solution, but the preparation of the crystallization precursor solution differs when N = 1 and N ≥ 2.

[0195] When N=1, the crystallization precursor solution is obtained by mixing fly ash with alkali, or further mixing with dopants, heating and melting, grinding, and diluting.

[0196] When N≥2, the crystallization precursor solution is obtained by mixing and diluting the filtrate and dopants obtained after the completion of the previous hydrothermal crystallization stage, with or without the addition of alkali as needed.

[0197] In one embodiment of the present invention, the mass ratio of the dopant (such as zeolite nucleus filter material / doped element particles) to the crystallization precursor solution is 1:(2-10), for example 1:(1-5), such as 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0198] In one embodiment of the present invention, the hydrothermal stage includes: adding dopant elements, aging, and hydrothermal process to obtain crystalline composite element crystals.

[0199] The hydrothermal stage includes a repeated hydrothermal process involving the addition of two dopant elements, which can be adjusted according to the types and / or contents of trace elements required by the composite doped plant. Preferably, the dopant elements are added before the start of the hydrothermal process to introduce the specified elements and allow them to uniformly form highly active catalytic sites.

[0200] Example 3

[0201] In this embodiment, the macronutrient loading is introduced by applying zeolite-based core material to animal digestive waste and / or by using zeolite-based core material as a composting additive for farmyard manure to adsorb the odor of overflowing ammonia nitrogen and hydrogen sulfide / or by mixing zeolite-based core material with ammonia nitrogen-enriched farmyard manure organic matter.

[0202] For example, the nanocomposite zeolite material is mixed with ammonia-nitrogen-enriched farmyard manure at a ratio of 1:(1-10), such as 1:3 (in a simple farmyard manure field composting process). A large amount of ammonia nitrogen and hydrogen sulfide volatiles will be adsorbed and loaded into the nanocomposite zeolite material. Preferably, at the end of the composting period, the farmyard manure composting material and the added nanocomposite zeolite material can be coated with a humic acid coating at a ratio of (1-10):1, such as 3:1.

[0203] Example 4

[0204] In this embodiment, after loading macronutrient elements (such as one or more of N, P, K and / or S) onto the zeolite core material, the zeolite core material obtained in Example 1 is immersed in a cationic solution containing different fertilizer active ingredients, such as ammonium nitrate, potassium nitrate, potassium phosphate, synthetic ammonia, urea and / or sodium nitrate. The mass ratio of the zeolite core material to the compound containing the fertilizer active ingredient cationic solution is 1:1. Then, the humic acid is coated to prepare the humic acid-coated slow-release fertilizer loaded with various macronutrients (N, P, K, S). The fertilizer is then compared with chemical fertilizers containing the same chemicals, i.e., the effects of commercial fertilizers in the form of potassium nitrate, ammonium nitrate, potassium phosphate, synthetic ammonia, urea or sodium nitrate are compared.

[0205] Example 5

[0206] In this embodiment, during the synthesis and crystallization of fly ash zeolite, potassium hydroxide, an activator containing the nutrient element "potassium," is used to prepare potassium zeolite; while macronutrient elements are "loaded" into the humic acid polymer coating. For example, in the synthesis of artificial humic acid, a salt containing macronutrient elements is added to react and obtain humate materials. In the synthesis of artificial humic acid, adding potassium salts containing macronutrient elements can yield two corresponding organic polymer materials: potassium fulvic acid (potassium humate) and potassium humic acid (potassium humate); the humate is then mixed with potassium zeolite for use.

[0207] The slow-release fertilizer in this embodiment is used according to traditional fertilization practices and has a better water retention effect compared to traditional commercial fertilizers.

[0208] Example 6

[0209] A method for preparing a composite material includes spraying a humic acid solution onto a zeolite-based core through a spray nozzle to obtain the composite material.

[0210] Example 7

[0211] A method for preparing a composite material includes spraying a humic acid solution onto a zeolite-based core through a spray nozzle in a fluidized bed to obtain the composite material.

[0212] Example 8

[0213] A composite material comprising a zeolite-based core (or zeolite / geopolymer material, zeolite-based core porous particles) in which nutrients are adsorbed and loaded within the pores, and a humic acid polymer slow-release coating covering the zeolite-based core.

[0214] Main chemicals: sodium hydroxide, potassium hydroxide, hydrogen peroxide, fertilizer elements, etc.

[0215] Main raw materials: fly ash, metakaolin, peat, lignite, agricultural waste biomass, etc.

[0216] Preparation of zeolite-based core materials:

[0217] (1) Preparation of the nucleus solution for the zeolite-based core precursor: The synthesized zeolite-based material may contain beneficial mineral elements. In this embodiment, the dopant element refers to "trace elements required by plants but lacking in arable land". In this embodiment, only cerium oxide nanoparticles are used as the dopant element. This demonstrates that one, two, or more dopant elements, including but not limited to those mentioned above, can be introduced into the nucleus solution of the zeolite-based material precursor through the process.

[0218] The zeolite-based core precursor crystal nucleus solution described in this embodiment is mainly prepared from the combustion fly ash of coal-fired power boilers through a two-stage process of melting and hydrothermal treatment to obtain an alkaline solution containing zeolite crystal nuclei of aluminosilicate monomer oligomers.

[0219] The steps of the melting stage are as follows: mix fly ash and NaOH in a mass ratio of 1:2, heat at 650℃ for 1.5h to melt; grind and dilute to a 2mol / L solution; let stand and age for 24h;

[0220] The hydrothermal stage method is as follows: the aging solution is ultrasonically treated for 15-90 minutes, and then hydrothermally activated and crystallized at 120℃ for 2 hours to obtain a zeolite-based core precursor crystal nucleus solution (this solution can also be filtered to obtain crystalline zeolite particles).

[0221] During the hydrothermal stage, nanocrystal nuclei containing 1 to 2 doped elements can be added to the solution remaining after filtering the zeolite crystal particles. Under the condition of repeated hydrothermal stage operation with a base concentration of 1 to 2.5 mol, it is preferable to adjust the mineral element composition of the zeolite-based core precursor crystal nuclei solution according to the type and / or content of trace elements required by the plant.

[0222] The precursor nucleus solution doped with a specified element refers to a solution obtained by mixing the zeolite nucleus filter material obtained from the previous hydrothermal crystallization stage and the solution obtained by repeating the hydrothermal crystallization stage with the filtrate after separation. Repeating the hydrothermal crystallization stage with the filtrate after separation allows for the introduction of dopant elements (such as commercially available nano-cerium dioxide powder (99.9% purity) at 0.01% fly ash mass in this embodiment) as dopant element raw materials to grow zeolite nuclei on the surface of the nucleus particles in the zeolite-based core precursor nucleus solution; the mass ratio of the zeolite nucleus filter material / cerium dioxide powder to the crystallization precursor solution is 1:5.

[0223] In this embodiment, the ratio of "zeolite-structured crystalline material / geologically aggregated semi-crystalline material" in the zeolite-based core porous body synthesized in Example 8 can be adjusted by regulating the mass ratio of zeolite nucleus filter material / cerium dioxide nanopowder to the crystallization precursor solution. (See appendix for details) Figure 13 (The process flow for introducing doping elements);

[0224] (2) Add 2.5 wt% hydrogen peroxide solution (concentration of 20% H2O2) and 0.15 wt% silicon powder (Si) foam generator, 50 wt% metakaolin powder and 2 wt% vegetable oil to the zeolite crystal nucleus solution and mix them evenly. At the same time, add 15M sodium hydroxide solution and stir thoroughly to form a zeolite-based polymer precursor mortar with a solid-liquid ratio of 1:1.

[0225] (3) After injecting the zeolite-based polymer precursor mortar into the curing mold, microwave it for 20-40 seconds, place the mold in a dry environment at 80℃ for 4 hours, and then demold it. Let it stand at room temperature for 2 weeks to complete the curing.

[0226] (4) After the solid is crushed, the free alkali is washed off with deionized water, dried and granules are screened according to a particle size of 2 mm.

[0227] The preferred particle size of the zeolite-based core porous particles is 2 mm, and the preferred thickness of the humic acid polymer coating is 1 mm.

[0228] Zeolite-based core porous body (without added nutrients); by adding doping elements, various trace mineral elements can be quantitatively selected to include: magnesium (Mg), iron (Fe), zinc (Zn), molybdenum (Mo), boron (B), selenium (Se), etc.; such as rare earth element cerium (Ce) included in this embodiment.

[0229] (5) The zeolite-based core material particles have a porosity / volume ratio of 0.583, a mass density of <0.6 g / cc, and a loading / volume ratio of ammonia nitrogen aqueous solution of 0.76.

[0230] Alternatively, the zeolite-based core can be loaded with a molten urea solution through adsorption. For example, taking the adsorption of a molten urea solution as an example, the prepared zeolite-based core material particles are immersed in a molten urea solution at 140°C for 30 minutes, then removed and cooled at room temperature to obtain a zeolite-based core with a urea loading rate of 48.9 wt%. The mass ratio of ammonia nitrogen molten solution adsorbed by the zeolite-based core is 1:1 to 1:3.

[0231] (6) Several processes for humic acid-coated zeolite-based core loading:

[0232] The artificial humic acid contains aromatic hydrocarbons and long-chain aliphatic hydrocarbons. The aromatic hydrocarbon content is 7.43%, and the long-chain aliphatic hydrocarbon content is 7.15%. The hydrothermal humification (HTH) is carried out according to the method disclosed in Fan Yang et al., Ahydrothermal process to turn waste biomass into artificial fulvic and humic acids for soil remediation, Science of the Total Environment, 686 (2019), 1140-1151.

[0233] In this embodiment, based on the aforementioned disclosed method, lignite, peat coal, and other materials rich in humic substances are mixed with biomass at a dry mass ratio of 1:1 to 5:1. Then, 8 liters of water are added per kilogram of dry mass mixture to obtain a mixed slurry. 3 wt% hydrogen peroxide and 5 wt% iron-rich solid acid catalyst are added as auxiliary agents, and a humic acid coating slurry is prepared as the zeolite-based core coating material through a CO-HTH (co-liquid humification reaction at 160°C for 120 minutes) process.

[0234] The humic acid-coated zeolite-based core composite material with nutrient loading is a high-nutrient-loading and slow-release composite material. The measured cation exchange capacity (CEC) of the composite material is 1500-3500 cmol(+) / kg, and the mass density is 1.2-2.2 g / cc.

[0235] The method for preparing the humic acid-coated zeolite-based composite material involves spraying a humic acid coating slurry solution through a nozzle onto a zeolite substrate to obtain the composite material (see appendix). Figure 11 ).

[0236] The method for preparing the humic acid-coated zeolite-based composite material includes spraying a humic acid coating slurry solution onto a zeolite-based core through a nozzle in a fluidized bed to obtain the composite material (see appendix). Figure 11 ).

[0237] The method for preparing the humic acid-coated zeolite-based composite material includes various methods of immersing a nutrient-loaded zeolite-based core in a humic acid coating slurry solution to complete the coating, thereby preparing the composite material (see appendix). Figure 11 ).

[0238] Example 9

[0239] In this embodiment, the adsorption effect of zeolite-based core on ammonia nitrogen nutrients in the soil environment is tested. The specific method is as follows:

[0240] The adsorption effect of zeolite-based materials on ammonia nitrogen in soils with different humic acid contents was determined by mixing zeolite-based core materials with ammonia nitrogen fertilizer elements, applying them to animal digestive waste for adsorption, and / or using zeolite-based core materials as compost additives for farmyard manure to adsorb the odor of overflowing ammonia nitrogen and hydrogen sulfide; or mixing zeolite-based core materials with ammonia nitrogen-enriched farmyard manure organic matter.

[0241] First, the zeolite-based core particles prepared in Example 8 were activated by soaking in the acid precipitation solution of fulvic acid; then the particles were dried, ground and passed through an 80-mesh sieve to form powder, which was then mixed with urea at a mass ratio of 3:7 and used as nitrogen fertilizer A for later use.

[0242] Take the top 0-20cm of coastal sandy soil, grind it and sieve it to a particle size of 2mm, mix it with urea at a mass ratio of 3:7, and use it as nitrogen fertilizer B.

[0243] Four groups of potted soil samples with different humic acid contents were prepared. The humic acid concentrations in the soil of the four groups of potted plants were 1% v / v, 3% v / v, 5% v / v, and 7% v / v, respectively. Each group was divided into two pots: pot A, which was to be treated with nitrogen fertilizer A, and pot B, which was to be treated with nitrogen fertilizer B. The amount of nitrogen fertilizer A or B applied to the potted plants was 10% v / v of the humic acid content in the pot. After one week of cultivation, the nitrogen content in the soil of potted plants A and B was measured using the Kjeldahl method. The results are shown in Table 1 below.

[0244] Table 1

[0245] Humic acid concentration variable Nitrogen content in potting soil B Nitrogen content in potting soil A 1％ 33.23％ 0.422％ 3％ 42.43％ 0.512％ 5％ 39.81％ 0.493％ 7％ 36.81％ 0.432％

[0246] As can be seen from the results in Table 1, the zeolite-based core material prepared by this invention has a strong adsorption capacity for ammonia nitrogen in the soil. It can be used as a nitrogen fertilizer carrier to reduce nitrogen fertilizer loss and help to recycle waste nutrients from the livestock industry.

[0247] For example, mixing the zeolite-based core material with ammonia-nitrogen-enriched farmyard manure at a ratio of 1:(1-10), such as 1:3 (a simple farmyard manure field composting process), will adsorb and load a large amount of ammonia nitrogen and hydrogen sulfide volatiles into the zeolite-based material. After being coated, it can be used as organic fertilizer. Preferably, at the end of the composting period, the farmyard manure composting material and the added zeolite-based material can be mixed at a ratio of (1-10):1, such as 3:1, which can improve the conversion efficiency of ammonia nitrogen nutrient waste and reduce air pollution.

[0248] Example 10

[0249] The zeolite-based core material prepared in Example 8 is immersed in a cationic compound solution containing different fertilizer active ingredients (such as ammonium nitrate, potassium nitrate, potassium phosphate, synthetic ammonia, urea, and nutrient solutions such as potassium chloride and potassium dihydrogen phosphate), which can load nutrients at a high capacity. The mass ratio of the cationic compound solution containing fertilizer active ingredients to the zeolite-based core material can be selected between 1:1 and 3:1. The zeolite-based core material obtained after the humic acid coating adsorbs the cationic compound solution containing fertilizer active ingredients is a humic acid-coated zeolite-based slow-release fertilizer containing macronutrients (N, P, K, S).

[0250] Compared to the same amount of chemical fertilizer nutrients, the humic acid-coated zeolite-based macronutrient (N, P, K, S) slow-release fertilizer obtained in this embodiment is on the same order of magnitude. Therefore, the humic acid-coated zeolite-based nutrient slow-release fertilizer prepared in this embodiment has the same use value as chemical fertilizer nutrients; at the same time, the humic acid-coated zeolite-based macronutrient (N, P, K, S) slow-release fertilizer prepared in this embodiment also reduces fertilizer runoff and loss, so its actual utilization efficiency will be much higher than that of chemical fertilizer nutrients.

[0251] Based on the basic performance data of zeolite-based core particles (pore volume ratio > 0.6, mass density < 0.6 g / cc), the following three nutrient solutions were physically adsorbed at a ratio of 2:1, and the mass fraction of each nutrient was measured:

[0252] (1) Urea loading: Zeolite core particles were immersed in urea melt at 140℃ for 30 minutes, and then cooled at room temperature. The nitrogen loading was measured to be 18wt%.

[0253] (2) Potassium chloride loading: At 90°C, the zeolite core particles were immersed in a saturated potassium chloride solution for 30 minutes, then removed and dried. The potassium chloride content was measured to be 36 wt%, and the potassium content was measured to be 19 wt%.

[0254] (3) Potassium dihydrogen phosphate loading: The zeolite core particles were immersed in a saturated potassium dihydrogen phosphate solution at 90°C for 30 minutes, then removed and dried. Based on the calculation that 45g of crystals can be precipitated from the porous body after drying in each liter of saturated solution at room temperature, the potassium dihydrogen phosphate content was 48wt%, of which the mass ratio of potassium to phosphorus was 44:17.

[0255] The morphology of nutrient solution after physical adsorption on zeolite-based core (see appendix) Figure 14 ).

[0256] Example 11

[0257] In this embodiment, when preparing the zeolite nucleus solution, a potassium-based activator (KOH) is preferred to promote the initial cation of the crystal nuclei (CEC) to be potassium ions. Subsequently, when the nucleus solution is mixed with other aluminosilicate raw materials to form mortar, a potassium-based activator (KOH) is still preferred to be added to ensure the specific alkalinity (10-15M) of the geopolymerization process. This allows for the synthesis of zeolite-based materials containing 8-18 wt% potassium. The zeolite-based core is fabricated into porous foam solid particles, which can physically adsorb urea, thus increasing the ammonium nitrogen loading rate of the composite material. The specific preparation steps of the composite material are as follows:

[0258] (1) Prepare a potassium-loaded zeolite-based core precursor crystal nucleus solution according to the method for preparing the crystal nucleus solution of the zeolite-based core precursor described in Example 8, the only difference being that: an equal amount of potassium hydroxide is used to replace sodium hydroxide and mixed with fly ash to carry out a melting reaction to prepare potassium zeolite crystal nucleus solution.

[0259] (2) The preparation steps of the zeolite-based polymer precursor mortar are the same as those described in Example 8, including the steps of mixing and adding H2O2, silica powder, vegetable oil, etc.; only an equal amount of 10-15M potassium hydroxide solution is used to replace sodium hydroxide to complete the preparation of zeolite-based polymer precursor mortar with a solid-liquid ratio of 1:1.

[0260] (3) The same steps as described in Example 8 are used. After injecting the zeolite-based polymer precursor slurry into the curing mold, the mold is microwaved for 20 to 40 seconds. After demolding, the mold is placed in a dry environment at 80°C for 4 hours and then left to stand at room temperature for 2 weeks to complete the curing.

[0261] (4) The same steps as described in Example 8 are used. After the solid is crushed, deionized water is used to wash away the free alkali, and the solid is dried and the particles are screened according to a particle size of 2 mm.

[0262] (5) The zeolite-based core is adsorbed with a urea hot melt solution, that is, the prepared zeolite-based particle material is immersed in a urea hot melt solution at 140°C for 30 minutes, and then cooled at room temperature to obtain a zeolite-based core with a urea loading rate of 48.9 wt%.

[0263] (6) If the particle size of the zeolite-based core porous particles is selected as 2 mm, the thickness of the humic acid polymer coating is preferably 1 mm: The zeolite-based core particle material loaded with nutrients is immersed in the humic acid coating slurry solution, and the humic acid coating on the surface of the zeolite-based core porous particles is completed by stirring. After granulation and drying, the composite material is obtained, namely, humic acid-coated potassium zeolite-based nitrogen nutrient slow-release fertilizer, abbreviated as humic acid composite ecological slow-release fertilizer (see Appendix). Figure 15 ).

[0264] The key nutrient content and beneficial mineral element comparison of the humic acid compound ecological slow-release fertilizer prepared in this embodiment are shown in Table 2 below.

[0265] Table 2

[0266]

[0267]

[0268] Note: "-" in the table indicates not applicable; "ND" indicates not detected.

[0269] Example 12

[0270] After applying 20g of the composite material (humic acid compound ecological slow-release fertilizer) prepared in Example 11 to the potted soil, the growth results of the potted plants after 90 days are shown in the figure. Figure 16 :

[0271] (1) Detect the pH value of the potted soil

[0272] Soil pH is a crucial parameter for plant growth, as deviations from the optimal pH level affect nutrient availability. Most plant root nutrients function optimally in soils with a pH of 5.5-7. The humic acid compound slow-release fertilizer prepared in this invention contains 6-7 times its own weight in water, which can improve plant survival rates under drought conditions. Furthermore, the humic acid material contains a large number of -carboxyl groups and -COO groups. - It can react with OH in the soil solution - and H + The reaction occurs to buffer the soil near the roots, stabilizing the soil pH to approximately 7. The effect of using the humic acid compound slow-release fertilizer of this invention on soil pH changes within 90 days is shown in [link to relevant documentation]. Figure 16 .

[0273] (2) Impact on soil microbial biomass and nutrient bioavailability

[0274] Humic acid can stimulate soil microbial activity, promoting the completion of many important biological processes mediated by soil microorganisms, such as nutrient cycling and the degradation of pesticides and pollutants. Soil microorganisms also require biopolymer organic carbon to complete their own energy and cell synthesis. The humic acid coating in the humic acid compound ecological slow-release fertilizer of this invention helps soil microorganisms overcome the nutrient stress often encountered when using chemical organic coating materials. Furthermore, the humic acid polymer colloidal coating, acting as an encapsulation layer for zeolite-based crystal particles, allows the soil environment to form a contact channel with the zeolite-based fertilizer medium through the amphiphilic humic acid coating layer, thus stimulating the interaction between soil water and mineral nutrients in the humic acid colloid. This results in the efficient utilization of high-load macronutrients during the slow diffusion process of the colloid. Nutrient cations are released only according to the cation concentration after plant absorption. The humic acid coating layer significantly increases the availability of phosphorus in calcareous soils and improves the diffusion rate of soluble phosphorus. Humic acid can further induce more plant nitrogen absorption. A rough observation of plant growth is shown in the appendix. Figure 16 .

[0275] (3) The impact of water retention capacity

[0276] Humic acid has outstanding soil water retention properties, especially effective in improving the water retention capacity of sandy soils. This invention unexpectedly discovered that the characteristics of the hydrophilic groups and network structure of the humic acid polymer at the microscale in the humic acid compound ecological slow-release fertilizer, as well as the strong hydrogen bonds formed between water molecules and these biopolymers, play a role in water retention.

[0277] (4) Impact on plant growth and soil organic carbon

[0278] Humic acid coating materials can have a positive long-term impact on plant growth due to their role in controlling nutrient release and soil stabilization. When the soil organic carbon content is below 8%, there is a positive correlation between the percentage of organic carbon and plant growth. Humic acid can not only stimulate plant growth, but also has antiviral effects. This effect of humic acid reflects: (1) the affinity of humic acid polymers for viral receptors in the soil, which blocks virus-specific receptors; (2) the induction of the immune system to fight pathogens. Humic acid can stimulate seed germination (accelerate seed germination) and seedling growth, and is a "broad-spectrum" health growth regulator. Adding humic acid to the soil can immediately promote the activity of many beneficial microorganisms, which are the "immune system" for preventing and controlling plant diseases. Pathogens are toxic, and many trace metals are catalysts for microbial degradation of toxins, and are essential "vitamins" for maintaining the healthy activity of beneficial microorganisms in the defense and degradation of toxins. This invention unexpectedly discovered that the humic acid coating in the humic acid compound ecological slow-release fertilizer can play a role in anti-oxidation, free radical protection, and promoting the activity of plant and animal cells in the soil ecosystem, thus providing a basic buffer for the stability of the environment for complex life processes.

[0279] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A composite material, characterized in that, It comprises a zeolite-based core and a humic acid polymer coating covering the zeolite-based core. Preferably, the zeolite core is a zeolite core porous body. Preferably, the particle size of the zeolite core is 0.5 mm to 10 mm. Preferably, the thickness of the humic acid polymer coating is 0.2 to 0.6 times the particle size of the zeolite-based core. More preferably, the thickness of the humic acid polymer coating is 0.1 mm to 6 mm. Preferably, the zeolite core may be loaded with macronutrients (e.g., N, P, K and / or S) and / or contain one, two or more micronutrients required by plants, such as magnesium (Mg), iron (Fe), zinc (Zn), molybdenum (Mo), boron (B), and selenium (Se). Preferably, the humic acid polymer coating can be a coating formed by encapsulating natural humic acid, artificial humic acid, or humic acid organic polymers on a zeolite-based core. Preferably, the mass ratio of the humic acid polymer coating to the zeolite-based core is 1:1 to 10:

1. Preferably, the artificial humic acid is a humic acid organic polymer material prepared by the HTH process using mineral humic acid extracted from lignite, peat coal, etc., and / or biomass as raw materials. For example, the lignite source includes peat.

2. The composite material according to claim 1, characterized in that, The zeolite-based core is a zeolite / geopolymer porous body. Preferably, the zeolite-based core is an aluminosilicate hydrate synthesized from fly ash. Preferably, the inorganic crystalline phase material within the pores is zeolite synthesized from fly ash. Preferably, the zeolite structure of the crystalline phase material within the pores is at least one of the following: FAU / Zeolite structure, FAU / Zeolite Y-type structure, FAU / Zeolite A-type, X-type, LTA / Zeolite type, etc. Preferably, the zeolite-based core porous body is a geopolymer prepared by an alkaline hydrothermal sol-gel method using fly ash and pre-prepared zeolite crystalline phase materials as its main raw materials. Preferably, the method for preparing the zeolite crystalline phase material includes the following steps: a zeolization process is performed on fly ash through a two-stage fusion (melting and hydrothermal) process to prepare the zeolite crystalline phase material. Preferably, the melting stage process includes: mixing fly ash with alkali, heating and melting, grinding, and diluting to obtain a crystallization precursor solution. The alkali is selected from strong alkalis, such as sodium hydroxide or potassium hydroxide. The heating and melting temperature can be 500-600℃, and the time can be 1-9 hours. Preferably, the hydrothermal stage includes: adding dopant elements, aging, and hydrothermal processes to obtain crystalline composite element crystals. Preferably, the hydrothermal stage may include a repeated hydrothermal process with N doping elements, where N is an integer equal to or greater than 1. Preferably, doping elements are added, preferably before the start of the hydrothermal process where N>1, to introduce specific elements and make these elements uniformly form highly active catalytic sites. Preferably, the dopant element is introduced through dopants, including but not limited to nanoparticles of one, two or more dopant elements, basic compounds and / or nuclei. Preferably, the dopant contains trace elements that are lacking in fly ash but required by plants, as described above. Preferably, the dopant is added to the crystallization precursor solution, but the preparation of the crystallization precursor solution differs when N=1 and N≥2: When N=1, the crystallization precursor solution is obtained by mixing fly ash with alkali, or further mixing with dopants, heating and melting, grinding, and diluting. When N≥2, the crystallization precursor solution is obtained by mixing and diluting the filtrate and dopants obtained after the completion of the previous hydrothermal crystallization stage, with or without the addition of alkali as needed. Preferably, the mass ratio of the dopant to the crystallization precursor solution is 1:(1-20), for example 1:(1-5). Preferably, the hydrothermal process is carried out at a temperature of 90–170°C for a duration of 2–48 hours. Preferably, the method for preparing the zeolite-based core crystalline material includes the following steps: (1) Fly ash is mixed with alkali, heated to melt, ground, and diluted to obtain the first crystallization precursor solution; (2) The first crystallization precursor solution is subjected to a hydrothermal process and then filtered to obtain crystals and the first filtrate. (3) The first filtrate and the dopant containing element 1, and with or without the addition of alkali as needed, are mixed and diluted to obtain a second crystallization precursor solution. The second crystallization precursor solution is filtered through a hydrothermal process to obtain crystals containing element 1 and a second filtrate. (4) The filtrate obtained in the subsequent hydrothermal stage is processed in step (3). The dopant contains element 2, and crystals and filtrate containing element 2 are obtained. The process ends when all the elements that need to be doped are incorporated into the crystal. Element 1 and element 2 may be the same or different, preferably different; both are selected from the above-mentioned doping elements. Element 1 represents one, two, or more elements; Element 2 represents one, two, or more elements. Preferably, the nanocomposite zeolite material has a tertiary porous structure: The pore size of the first-order pore structure is no more than 10 nm, for example, no more than 5 nm, and preferably less than 2 nm (i.e., micropores); The pore size of the second-order pore structure (also known as mesopore) is equal to or greater than that of the first-order pore structure, but does not exceed 50 nm; The pore size of a third-order pore structure (also known as a macropore) is greater than 50 nm, for example, greater than 50 nm and not exceeding 500 nm, such as 200 nm. Preferably, the sum of the specific surface areas of the zeolite-based core is 150–1500 m². 2 / g, for example 300~1200m 2 / g, such as 500-1000m 2 / g. Preferably, the cation exchange capacity (CEC) of the zeolite core is 150-250 cmol(+) / kg, which is much higher than that of soil humic substances. Preferably, the pore volume ratio of the zeolite-based core is more than 50%, for example, more than 60%, such as 65-80%. Preferably, the diameter of the zeolite-based core pore aggregate particles is 0.5 mm to 10 mm. Preferably, the mass density of the zeolite-based core porous aggregate is 0.5-1.0 g / cc. Preferably, the zeolite-based core has water-holding capacity (water retention capacity > 60 wt%). Preferably, the zeolite-based core has acid and alkali resistance properties and is soluble only in strong acids (low pH value).

3. The method for preparing the composite material according to any one of claims 1-2, characterized in that, The preparation method includes coating humic acid onto a slow-release core of a nanocomposite zeolite material to prepare the composite material. Preferably, the coating method can be one of "impregnation method", "coating method" or "fluidized bed coating method".

4. The application of the composite material according to any one of claims 1-2 as a slow-release medium material, preferably as a slow-release medium material for agricultural use. Preferably, the composite material serves as a slow-release medium for macronutrient elements (e.g., N, P, K, and / or S). Preferably, the composite material serves as a slow-release medium for the herbicide.

5. A slow-release fertilizer, characterized in that, It comprises the composite material according to any one of claims 1-2, wherein the nanocomposite zeolite material in the composite material serves as a carrier for the active ingredients of the fertilizer. Preferably, the active ingredient in the fertilizer is a macronutrient element, such as N, P, K and / or S. Preferably, the composite material in the slow-release fertilizer contains one, two or more specified elements. Preferably, the composite material in the slow-release fertilizer is a mixture of composite materials containing different specified elements. Preferably, the composite material in the slow-release fertilizer is a mixture of composite materials that do not contain the specified element and those that contain at least one specified element. Preferably, the slow-release fertilizer is obtained by immersing the composite material in a cationic solution containing the active fertilizer ingredients; Preferably, the cation containing the fertilizer active ingredient is provided by compounds such as ammonium nitrate, potassium nitrate, potassium phosphate, synthetic ammonia, urea, and / or sodium nitrate; Preferably, the mass ratio of the composite material to the compound containing the fertilizer active ingredient cation is (3-10):1, for example, 7:

1. Preferably, the structure (integral structure and pore structure) and specific surface area of ​​the slow-release fertilizer are basically consistent with those of the composite material. Preferably, the slow-release fertilizer can be a solid-liquid mixture or a solid fertilizer. Preferably, the macronutrient elements are loaded during the preparation of the nanocomposite zeolite material. Preferably, the macronutrient elements are active ingredients of chemical fertilizers, such as N, P, K, and / or S elements. Preferably, the macronutrient elements are obtained by immersing nanocomposite zeolite materials in a cationic solution containing fertilizer active ingredients.

6. A slow-release herbicide, characterized in that, It contains the composite material and herbicide according to any one of claims 1-2.

7. A soil conditioner, characterized in that, The soil conditioner contains the composite material according to any one of claims 1-2. The soil conditioner may be a liquid-solid mixture conditioner or a solid conditioner.

8. A plant fertilizer, characterized in that, The plant fertilizer contains the composite material according to any one of claims 1-2. The plant fertilizer may be a liquid-solid mixture or a solid fertilizer.

9. A plant growth regulator, characterized in that, The composite material contained in any one of claims 1-2.

10. A wastewater treatment agent, characterized in that, The composite material contained in any one of claims 1-2.

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