Production method of organic biological compound phosphate fertilizer

Abstract

The invention discloses a production method of an organic biological compound phosphate fertilizer, and belongs to the technical field of preparation of biological organic fertilizers. The preparation method comprises the following steps: constructing oxidized biomass charcoal from a biomass raw material, combining the oxidized biomass charcoal with carboxymethyl chitosan, carrying out oxidation treatment to obtain formylated oxidized biomass charcoal, and carrying out cross-linking reaction on the formylated oxidized biomass charcoal and amino acid to form the amino acid modified oxidized biomass charcoal. And finally, mixing the amino acid modified oxidized biomass charcoal with calcium superphosphate, adding water, stirring, and then drying to constant weight to obtain the organic biological compound phosphate fertilizer, thereby realizing a slow-release effect and further weakening the aim of influencing release of the phosphate fertilizer and exerting the fertilizer efficiency due to adsorption and combination of soil metal ions on the phosphate fertilizer.

Description

Technical Field

[0001] The invention belongs to the technical field of bio-organic fertilizer preparation, and particularly relates to a method for producing organic bio-compound phosphate fertilizer. Background Art

[0002] Fertilizers are used to improve soil quality and promote plant growth. They usually contain nutrients required by plants. They play a vital role in agricultural production and help crops increase yield and improve quality by providing basic nutrients such as nitrogen, phosphorus, and potassium. Fertilizers can be divided into many types, mainly including the following: (1) Organic fertilizers: mainly fertilizers made from natural materials such as animal and plant residues or feces. They not only provide nutrients required by plants, but also improve the structure and microbial activity of the soil. Common organic fertilizers include: compost (made from plant residues, animal feces, etc. that have been naturally decomposed and are rich in organic matter and various trace elements), green manure (grown into the soil after planting specific plants to increase the nitrogen content and organic matter of the soil) and animal manure (such as cow dung, chicken manure, etc., which are rich in nutrients such as nitrogen, phosphorus, and potassium); (2) Inorganic fertilizers: mainly refers to fertilizers made through chemical synthesis or mineral extraction, which usually contain highly concentrated plant nutrients. Mainly include: nitrogen fertilizer (such as urea, etc., mainly used to provide nitrogen required by plants), phosphorus fertilizer (such as ammonium phosphate, etc., mainly used to provide phosphorus and promote root growth) and potassium fertilizer (such as potassium chloride, potassium sulfate, etc., mainly used to improve plant resistance and fruit quality); (3) compound fertilizer: mainly a mixture of multiple nutrients in a certain proportion, which can simultaneously provide nitrogen, phosphorus, potassium and other nutrients; (4) trace element fertilizer: mainly used to supplement the trace elements required for plant growth, such as zinc, iron, boron, etc., although these elements are required in small amounts, they are essential for plant growth and development. However, with the rapid development of agriculture, the use of fertilizers has also increased year by year, which has had a significant impact on the environment. Phosphorus is one of the essential nutrients for crops and is crucial for high and stable crop yields. Because it easily combines with some metal ions in the soil to form precipitation and is not directly absorbed and utilized by crops, the utilization rate of phosphorus fertilizer in the season is low. To ensure high and stable yields, farmers apply large amounts of phosphate fertilizer during agricultural production. This causes the accumulation of ineffective phosphorus in the soil, reducing rather than increasing agricultural efficiency. It also leads to a series of environmental problems, such as soil compaction and eutrophication, and wastes phosphorus resources. To address the low utilization rate of traditional phosphate fertilizers and the challenges posed to the phosphate fertilizer industry by tight phosphate rock supply and demand, the development of new phosphate fertilizer products is imperative.

[0003] Patent CN117720382A discloses an agricultural compound phosphate fertilizer and a preparation method thereof. The invention subjects the extract slurry obtained by extraction and crystal growth in the wet-process phosphoric acid process to super-aeration flotation. Super-aeration microbubbles are introduced into the extract slurry through super-aeration flotation. After classification, an air flotation layer slurry and a floating residue layer slurry are obtained. The air flotation layer slurry is used as the base material and is directly mixed with straw, coal slime, layered silicate, phosphate rock, and straw fast-rot bacteria agent without filtering to obtain the agricultural compound phosphate fertilizer. Low-grade phosphate rock can be used, achieving the purpose of comprehensively utilizing phosphogypsum waste and low-grade minerals. It can also further solve the technical problem of waste accumulation in the existing phosphoric acid production process. Patent CN115353429A discloses a method for preparing phosphate fertilizer from phosphorus-containing iron tailings and the resulting phosphate fertilizer. This invention subjects the material to high-energy grinding and mechanical activation to increase the effective phosphorus content in the phosphorus-containing iron tailings, which can be directly absorbed by plants. Ultrafine grinding and activation of the phosphorus-containing iron tailings alters its crystal structure, changing its reactivity and increasing its effective phosphorus content, playing a significant role in improving phosphorus resource utilization. Patent CN114890842A discloses an environmentally friendly slow-release phosphate fertilizer based on the value-added utilization of agricultural solid waste and its preparation method. This invention uses crop straw, wood ash, eggshells, and chicken feathers as raw materials. Environmentally friendly modified porous biochar is prepared through microwave-assisted pyrolysis, activation and pore expansion, and surface functional modification. Finally, the modified porous biochar is enriched with phosphorus-rich wastewater to produce the environmentally friendly slow-release phosphate fertilizer, achieving slow release of the phosphate fertilizer and improving its utilization rate.

[0004] Phosphate fertilizers are commonly applied because they easily bind to metal ions in the soil, rendering them ineffective for plant use. However, this increased application can lead to excessively high phosphorus concentrations in the soil, affecting the soil's acid-base balance and potentially causing soil acidification, which in turn impacts crop growth. Furthermore, excess phosphate fertilizers can flow into rivers, lakes, and other water bodies through rainwater or irrigation, leading to eutrophication, algae blooms, and hypoxia, impacting aquatic life.

[0005] Therefore, designing an organic biological compound phosphate fertilizer that can slowly release phosphate fertilizer and weaken the adsorption and binding effect of soil metal ions on phosphate fertilizer is of great significance to avoid the adverse effects of excessive phosphate fertilizer application. Summary of the Invention

[0006] In response to the deficiencies of the prior art, the present invention constructs oxidized biochar from biomass raw materials, combines it with carboxymethyl chitosan, and then undergoes oxidation treatment to obtain aldehyde-modified oxidized biochar, which is then cross-linked with amino acids to form amino acid-modified oxidized biochar. Finally, the amino acid-modified oxidized biochar is mixed with superphosphate, stirred with water, and then dried to a constant weight to obtain an organic biological compound phosphate fertilizer. The organic biological compound phosphate fertilizer prepared by the above-mentioned inventive concept and preparation method solves the technical problems raised in the background art. Specifically, the technical solution of the present invention includes the following contents: A method for producing an organic biological compound phosphate fertilizer, comprising the following steps: The biomass raw materials are subjected to high-temperature carbonization treatment at 500°C to 600°C for 2h to 3h to obtain bio-based carbon materials; The bio-based carbon material is subjected to hydrogen oxidation and hydrogenation to obtain oxidized biomass carbon; The oxidized biochar and carboxymethyl chitosan are dispersed in anhydrous dichloromethane to obtain a dispersion, an acid catalyst and a water absorbent are added to the dispersion, mixed, heated to 40° C. to 50° C., reacted for 20 h to 24 h, and then filtered to obtain carboxymethyl chitosan-modified oxidized biochar; The carboxymethyl chitosan modified oxidized biochar is subjected to light-shielding oxidation treatment with an oxidant for 4 to 6 hours to obtain aldehyde-oxidized biochar; The aldehyde-modified oxidized biochar is dispersed in an amino acid aqueous solution and heated to 100° C. to 110° C. for reaction for 3 h to 5 h to obtain the amino acid-modified oxidized biochar; The amino acid modified oxidized biochar, water-soluble phosphate fertilizer and water are mixed and stirred for 2 hours to 3 hours, and then dried to obtain the organic biological compound phosphate fertilizer.

[0007] Furthermore, the biomass raw material includes straw, and peat can also be used.

[0008] Furthermore, the conditions for the hydrogen peroxide oxidation treatment include a mass concentration of hydrogen peroxide of 30% to 40% and a treatment time of 3 hours to 4 hours.

[0009] Furthermore, the weight ratio of the oxidized biochar: carboxymethyl chitosan: anhydrous dichloromethane is 1:3-5:200-300.

[0010] Furthermore, the acid catalyst includes 3-quinolineboronic acid.

[0011] Furthermore, the water absorbent includes 13X molecular sieve.

[0012] Furthermore, the weight ratio of the dispersion liquid: the acid catalyst: the water absorbent is 1: 0.08-0.1: 0.01-0.03.

[0013] Furthermore, the oxidant is sodium periodate.

[0014] Furthermore, the weight ratio of the carboxymethyl chitosan modified oxidized biochar to the oxidant is 1:0.5-0.7.

[0015] Furthermore, the amino acid aqueous solution includes an L-lysine aqueous solution with a mass concentration of 30% or an L-arginine aqueous solution with a mass concentration of 30%.

[0016] Furthermore, the water-soluble phosphate fertilizer includes superphosphate or triple superphosphate.

[0017] Furthermore, the weight ratio of the amino acid-modified oxidized biochar: water-soluble phosphate fertilizer: water is 1:0.4-0.6:300-500.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses biomass raw materials as carrier raw materials, obtains biomass carbon-based materials by high-temperature carbonization, and then oxidizes them to obtain oxygen-containing active groups such as hydroxyl and carboxyl groups on the surface, thereby obtaining oxidized biochar. The oxidized biochar and carboxymethyl chitosan are then mixed and ultrasonically dispersed in anhydrous dichloromethane, followed by the addition of a catalyst 3-quinolineboric acid and a water absorbent HX-113 molecular sieve for mixed catalysis to obtain carboxymethyl chitosan-modified oxidized biochar. The carboxymethyl chitosan-modified oxidized biochar is then treated with an oxidant to break the ortho-dihydroxy groups on the carboxymethyl chitosan structure to produce aldehyde groups, thereby obtaining aldehyde-modified oxidized biochar. The aldehyde-modified oxidized biochar is dispersed in an aqueous amino acid solution, followed by a heating reaction to promote cross-linking of the aldehyde groups and the amino groups on the amino acid structure to form amino acid-modified oxidized biochar. The amino acid-modified oxidized biochar is mixed with a water-soluble phosphate fertilizer, water is added, and stirring is performed, and then the organic biological compound phosphate fertilizer is dried to a constant weight. The present invention utilizes the adsorption properties of biomass carbon-based materials and oxidizes them to obtain oxidized biomass carbon. The oxidized biomass carbon can undergo amidation condensation through the oxygen-containing active group carboxyl group possessed by the oxidation with the amino group on the carboxymethyl chitosan, and then the carboxymethyl chitosan is introduced into the oxidized biomass to obtain carboxymethyl chitosan-modified oxidized biomass carbon. The carboxymethyl chitosan can form a slow-release structure through cross-linking, achieving a slow-release effect on phosphate fertilizer. The carboxymethyl chitosan-modified oxidized biomass carbon is then oxidized to obtain a functional group aldehyde group, and then the aldehyde-modified oxidized biomass carbon is modified with amino acids. The polar hydrophilic effect of the amino acids can increase the water absorption and water retention of the fertilizer, thereby improving the utilization efficiency of the fertilizer. Finally, the amino acid modified oxidized biochar is mixed with the water-soluble phosphate fertilizer and stirred with water. On the one hand, the phosphate fertilizer is adsorbed to the amino acid modified oxidized biochar through the physical adsorption of the biochar. On the other hand, the amino acid modified oxidized biochar contains a large number of oxygen-containing groups, which can form a coordination binding effect with the metal ions on the structure of the water-soluble phosphate fertilizer, thereby further binding the phosphorus element to the amino acid modified oxidized biochar, thereby increasing the phosphorus loading capacity. This is not only beneficial to improving the utilization efficiency of the fertilizer, but also has a positive effect on reducing the adverse effects of pollution and damage to the environment caused by excessive use of phosphate fertilizers. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions of the present invention through the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0021] 3-Quinolineboronic acid was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; 13X molecular sieve was purchased from Dalian Haixin Chemical Co., Ltd. Example 1

[0022] A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass straw to remove surface impurities, the straw was placed in a blast dryer at 80°C to dry out the surface moisture until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 500°C at a heating rate of 5°C / min. The particles were carbonized at this temperature for 2 hours and then naturally cooled to room temperature to obtain the bio-based carbon material. 10 parts by weight of biochar material was placed in a container, followed by the addition of 300 parts by weight of a 30% hydrogen peroxide solution. The container was then sealed and oxidized in a dark environment for 3 hours. After the oxidation treatment, the solid particles were collected by filtration and rinsed with distilled water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain oxidized biochar. Weigh 1 part by weight of oxidized biochar and 3 parts by weight of carboxymethyl chitosan and add them to 200 parts by weight of anhydrous dichloromethane solution, then place it in an ultrasonic disperser and ultrasonicate it at an ultrasonic power of 300W for 20 minutes to obtain a dispersion. Take 0.08 times the weight of the dispersion and add the 3-quinolineboronic acid catalyst to the dispersion, then take 0.01 times the weight of the dispersion and add the 13X molecular sieve water absorbent to the dispersion containing 3-quinolineboronic acid, mix them, stir and mix at a speed of 400r / min, then place it in a temperature environment of 40℃ for 20 hours, and keep stirring during the reaction. After the reaction is completed, filter to remove the solution and water absorbent, collect the carbon particles, then rinse the carbon particles with anhydrous ethanol, and then rinse with deionized water until the pH of the rinse water is neutral, and then place the rinsed carbon particles in a vacuum drying oven at 60℃ and dry to constant weight to obtain carboxymethyl chitosan modified oxidized biochar; Disperse 1 part by weight of carboxymethyl chitosan-modified oxidized biochar in deionized water, then add 0.5 parts by weight of sodium periodate and mix, then shield the mixture and stir at 100 r / min for 4 hours at room temperature. After the sodium periodate oxidation treatment, add 1 part by weight of ethylene glycol and mix for 1 hour, then filter and collect the solid particles. Rinse the solid particles with anhydrous ethanol and then with deionized water until the pH of the rinse water reaches neutral. Dry the rinsed solid particles in a vacuum drying oven at 60°C to constant weight to obtain the aldehyde-modified oxidized biochar. Ten parts by weight of formaldehyde-modified oxidized biochar were dispersed in 200 parts by weight of a 30% aqueous L-lysine solution and ultrasonically dispersed at 300 W for 10 minutes. The mixture was then stirred at 100 rpm and heated to 100°C for 3 hours under reflux. After the reflux reaction, the solid was collected by filtration and dried in a vacuum oven at 60°C to obtain amino acid-modified oxidized biochar. 0.4 parts by weight of water-soluble phosphate fertilizer superphosphate was weighed and added to 300 parts by weight of water and stirred to dissolve. Subsequently, 1 part by weight of amino acid-modified oxidized biochar was weighed and added to the superphosphate solution and mixed and stirred for 2 hours. The mixture was then evaporated and dried to remove water to obtain an organic biological compound phosphate fertilizer. Example 2

[0023] A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass straw to remove surface impurities, the straw was placed in a blast dryer at 80°C to dry out the surface moisture until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 550°C at a heating rate of 5°C / min. The carbonization treatment was carried out at this temperature for 2.5 hours, and then naturally cooled to room temperature to obtain the bio-based carbon material. 10 parts by weight of biochar material was placed in a container, followed by the addition of 300 parts by weight of a 34% hydrogen peroxide solution. The container was then sealed and oxidized in a dark environment for 3 hours. After the oxidation treatment, the solid particles were collected by filtration and rinsed with distilled water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain oxidized biochar. Weigh 1 part by weight of oxidized biochar and 4 parts by weight of carboxymethyl chitosan and add them to 240 parts by weight of anhydrous dichloromethane solution, then place it in an ultrasonic disperser and ultrasonicate it at an ultrasonic power of 300W for 20 minutes to obtain a dispersion. Take 0.09 times the weight of the dispersion of 3-quinolineboronic acid catalyst and add it to the dispersion, then take 0.02 times the weight of the dispersion of 13X molecular sieve water absorbent and add it to the dispersion containing 3-quinolineboronic acid, mix them, stir and mix at a speed of 400r / min, then place it in a temperature environment of 45°C for 20 hours of timed reaction, and keep stirring during the reaction. After the reaction is completed, filter to remove the solution and water absorbent, collect the carbon particles, then rinse the carbon particles with anhydrous ethanol, and then rinse with deionized water until the pH of the rinse water is neutral, and then place the rinsed carbon particles in a vacuum drying oven at 60°C and dry to constant weight to obtain carboxymethyl chitosan modified oxidized biochar; Disperse 1 part by weight of carboxymethyl chitosan-modified oxidized biochar in deionized water, then add 0.6 parts by weight of sodium periodate and mix, then shield the mixture and stir at 100 r / min at room temperature for 5 hours. After the sodium periodate oxidation treatment, add 1 part by weight of ethylene glycol and mix for 1 hour. Then, filter and collect the solid particles, rinse with anhydrous ethanol and then with deionized water until the pH of the rinse water reaches neutral, and then dry the rinsed solid particles in a vacuum drying oven at 60°C to constant weight to obtain the aldehyde-modified oxidized biochar. Ten parts by weight of aldehyde-modified oxidized biochar were dispersed in 240 parts by weight of a 30% aqueous L-lysine solution and ultrasonically dispersed at 300 W for 10 minutes. The mixture was then stirred at 100 rpm and heated to 100°C for 4 hours under reflux. After the reflux reaction, the solid was collected by filtration and dried in a vacuum oven at 60°C to yield amino acid-modified oxidized biochar. 0.5 parts by weight of water-soluble phosphate fertilizer superphosphate was weighed and added to 400 parts by weight of water and stirred to dissolve. Subsequently, 1 part by weight of amino acid-modified oxidized biochar was weighed and added to the superphosphate solution and mixed and stirred for 2 hours. The mixture was then evaporated and dried to remove water to obtain an organic biological compound phosphate fertilizer. Example 3

[0024] A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass straw to remove surface impurities, the straw was placed in a blast dryer at 80°C to dry out the surface moisture until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 550°C at a heating rate of 5°C / min. The carbonization treatment was carried out at this temperature for 3 hours, and then naturally cooled to room temperature to obtain the bio-based carbon material. 10 parts by weight of biochar material was placed in a container, followed by the addition of 300 parts by weight of a 38% hydrogen peroxide solution. The container was then sealed and oxidized in a dark environment for 4 hours. After the oxidation treatment, the solid particles were collected by filtration and rinsed with distilled water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain oxidized biochar. Weigh 1 part by weight of oxidized biochar and 5 parts by weight of carboxymethyl chitosan and add them to 280 parts by weight of anhydrous dichloromethane solution, then place it in an ultrasonic disperser and ultrasonicate it at an ultrasonic power of 300W for 20 minutes to obtain a dispersion. Take 0.1 times the weight of the dispersion and add the 3-quinolineboronic acid catalyst to the dispersion, then take 0.03 times the weight of the dispersion and add the 13X molecular sieve water absorbent to the dispersion containing 3-quinolineboronic acid, mix them, stir and mix at a speed of 400r / min, then place it in a temperature environment of 45°C for a timed reaction of 22 hours, and keep stirring during the reaction. After the reaction is completed, filter to remove the solution and water absorbent, collect the carbon particles, then rinse the carbon particles with anhydrous ethanol, and then rinse with deionized water until the pH of the rinse water is neutral, and then place the rinsed carbon particles in a vacuum drying oven at 60°C and dry to constant weight to obtain carboxymethyl chitosan modified oxidized biochar; 1 part by weight of carboxymethyl chitosan-modified oxidized biochar was dispersed in deionized water, followed by the addition of 0.7 parts by weight of sodium periodate, followed by mixing and stirring. The mixture was then shielded from light and stirred at 100 rpm for 6 hours at room temperature. After the sodium periodate oxidation treatment, 1 part by weight of ethylene glycol was added and stirred for 2 hours. The solid particles were then collected by filtration and rinsed with anhydrous ethanol and then with deionized water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain the aldehyde-modified oxidized biochar. Ten parts by weight of aldehyde-modified oxidized biochar were dispersed in 280 parts by weight of a 30% aqueous L-arginine solution and ultrasonically dispersed for 10 minutes at 300W. The mixture was then stirred at 100 rpm and heated to 110°C for reflux for 4 hours. After the reflux reaction, the solid was collected by filtration and dried in a vacuum oven at 60°C to obtain amino acid-modified oxidized biochar. 0.6 parts by weight of water-soluble phosphate fertilizer, heavy superphosphate, was weighed and added to 450 parts by weight of water and stirred to dissolve. Subsequently, 1 part by weight of amino acid-modified oxidized biochar was weighed and added to the heavy superphosphate solution and mixed and stirred for 3 hours. The mixture was then evaporated and dried to remove water to obtain an organic biological compound phosphate fertilizer. Example 4

[0025] A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass straw to remove surface impurities, the straw was placed in a blast dryer at 80°C to dry out the surface moisture until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 600°C at a heating rate of 5°C / min. The particles were carbonized at this temperature for 3 hours and then naturally cooled to room temperature to obtain the bio-based carbon material. 10 parts by weight of biochar material was placed in a container, followed by the addition of 300 parts by weight of a 40% hydrogen peroxide solution. The container was then sealed and oxidized in a dark environment for 4 hours. After the oxidation treatment, the solid particles were collected by filtration and rinsed with distilled water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain oxidized biochar. Weigh 1 part by weight of oxidized biochar and 5 parts by weight of carboxymethyl chitosan and add them to 300 parts by weight of anhydrous dichloromethane solution, then place it in an ultrasonic disperser and ultrasonicate it at an ultrasonic power of 300W for 20 minutes to obtain a dispersion. Take 0.1 times the weight of the dispersion and add the 3-quinolineboronic acid catalyst to the dispersion, then take 0.03 times the weight of the dispersion and add the 13X molecular sieve water absorbent to the dispersion containing 3-quinolineboronic acid, mix them, stir and mix at a speed of 400r / min, then place it in a temperature environment of 50℃ for 24 hours, and keep stirring during the reaction. After the reaction is completed, filter to remove the solution and water absorbent, collect the carbon particles, then rinse the carbon particles with anhydrous ethanol, and then rinse with deionized water until the pH of the rinse water is neutral, and then place the rinsed carbon particles in a vacuum drying oven at 60℃ and dry them to constant weight to obtain carboxymethyl chitosan modified oxidized biochar; 1 part by weight of carboxymethyl chitosan-modified oxidized biochar was dispersed in deionized water, followed by the addition of 0.7 parts by weight of sodium periodate, followed by mixing and stirring. The mixture was then shielded from light and stirred at 100 rpm for 6 hours at room temperature. After the sodium periodate oxidation treatment, 1 part by weight of ethylene glycol was added and stirred for 2 hours. The solid particles were then collected by filtration and rinsed with anhydrous ethanol and then with deionized water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain the aldehyde-modified oxidized biochar. Ten parts by weight of aldehyde-modified oxidized biochar were dispersed in 300 parts by weight of a 30% L-arginine aqueous solution and ultrasonically dispersed for 10 minutes at 300 W. The mixture was then stirred at 100 rpm and heated to 110°C for 5 hours under reflux. After the reflux reaction, the solid was collected by filtration and dried in a vacuum oven at 60°C to obtain amino acid-modified oxidized biochar. 0.6 parts by weight of water-soluble phosphate fertilizer, heavy superphosphate, was weighed and added to 500 parts by weight of water and stirred to dissolve. Subsequently, 1 part by weight of amino acid-modified oxidized biochar was weighed and added to the heavy superphosphate solution and mixed and stirred for 3 hours. The mixture was then evaporated and dried to remove water to obtain an organic biological compound phosphate fertilizer.

[0026] Comparative Example 1: A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass raw material straw to remove surface impurities, the surface moisture was dried in a blast dryer at 80°C until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 700°C at a heating rate of 5°C / min. The particles were carbonized at this temperature for 4 hours and then naturally cooled to room temperature to obtain a bio-based carbon material. The remaining process remained the same as in Example 4.

[0027] Comparative Example 2: A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass straw to remove surface impurities, the straw was placed in a blast dryer at 80°C to dry out the surface moisture until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 600°C at a heating rate of 5°C / min. The particles were carbonized at this temperature for 3 hours and then naturally cooled to room temperature to obtain the bio-based carbon material. 10 parts by weight of biochar material was placed in a container, followed by the addition of 300 parts by weight of a 50% hydrogen peroxide solution. The container was then sealed and oxidized in a dark environment for 5 hours. After the oxidation treatment, the solid particles were collected by filtration and rinsed with distilled water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain oxidized biochar. The remaining process remained the same as in Example 4.

[0028] Comparative Example 3: A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: The carboxymethyl chitosan in Example 4 was replaced by chitosan, and the rest of the process was the same as that of Example 4.

[0029] Comparative Example 4: A method for producing an organic biological compound phosphate fertilizer specifically comprises the following steps: After cleaning the biomass straw to remove surface impurities, the straw was placed in a blast dryer at 80°C to dry out the surface moisture until the weight remained unchanged. The dried straw was cut into small pieces and crushed in a grinder. The pieces were then passed through a 50-mesh sieve to obtain fine particles. The fine particles were placed in a tubular furnace and heated to 600°C at a heating rate of 5°C / min. The particles were carbonized at this temperature for 3 hours and then naturally cooled to room temperature to obtain the bio-based carbon material. 10 parts by weight of biochar material was placed in a container, followed by the addition of 300 parts by weight of a 40% hydrogen peroxide solution. The container was then sealed and oxidized in a dark environment for 4 hours. After the oxidation treatment, the solid particles were collected by filtration and rinsed with distilled water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain oxidized biochar. Weigh 1 part by weight of oxidized biochar and 5 parts by weight of carboxymethyl chitosan and add them to 300 parts by weight of anhydrous dichloromethane solution, then place it in an ultrasonic disperser and ultrasonicate it at an ultrasonic power of 300W for 20 minutes to obtain a dispersion. Take 0.1 times the weight of the dispersion and add the 3-quinolineboronic acid catalyst to the dispersion, then take 0.03 times the weight of the dispersion and add the 13X molecular sieve water absorbent to the dispersion containing 3-quinolineboronic acid, mix them, stir and mix at a speed of 400r / min, then place it in a temperature environment of 50℃ for 24 hours, and keep stirring during the reaction. After the reaction is completed, filter to remove the solution and water absorbent, collect the carbon particles, then rinse the carbon particles with anhydrous ethanol, and then rinse with deionized water until the pH of the rinse water is neutral, and then place the rinsed carbon particles in a vacuum drying oven at 60℃ and dry them to constant weight to obtain carboxymethyl chitosan modified oxidized biochar; 1 part by weight of carboxymethyl chitosan-modified oxidized biochar was dispersed in deionized water, followed by the addition of 0.7 parts by weight of sodium periodate, followed by mixing and stirring. The mixture was then shielded from light and stirred at 100 rpm for 6 hours at room temperature. After the sodium periodate oxidation treatment, 1 part by weight of ethylene glycol was added and stirred for 2 hours. The solid particles were then collected by filtration and rinsed with anhydrous ethanol and then with deionized water until the pH of the rinse water reached neutral. The rinsed solid particles were then dried in a vacuum drying oven at 60°C to constant weight to obtain the aldehyde-modified oxidized biochar. 0.6 parts by weight of water-soluble phosphate fertilizer, heavy superphosphate, was weighed and added to 500 parts by weight of water and stirred to dissolve. Subsequently, 1 part by weight of formaldehyde-oxidized biochar was weighed and added to the heavy superphosphate solution and mixed and stirred for 3 hours. The mixture was then evaporated and dried to remove water to obtain an organic biological compound phosphate fertilizer.

[0030] Determination of total phosphorus content: In accordance with the standard of "GB / T 17767.2-2010 Determination of organic-inorganic compound fertilizers - Part 2: Total phosphorus content", 1 g of the organic biological compound phosphate fertilizers obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were respectively weighed, and the total phosphorus content was determined by the sulfuric acid-hydrogen peroxide digestion method. The results are shown in Table 1 below.

[0031]

[0032] Sustained release performance test: 1.0 g of the organic biological compound phosphate fertilizer obtained in Examples 1 to 4 and Comparative Examples 1 to 4 was respectively placed in a 100-mesh nylon bag. The nylon bag was immersed in a plastic bottle containing 250 mL of distilled water, sealed, and placed in a constant temperature incubator at 25°C. On the 28th day, 50 mL of the solution was taken from the bottle and placed in a covered centrifuge tube, and the cumulative release rate of the phosphorus content was measured. The results are shown in Table 2 below.

[0033]

[0034] Water retention performance test: 1.0 g of the organic bio-compound phosphate fertilizer obtained in Examples 1-4 and Comparative Examples 1-4 was mixed uniformly with 50 g of soil (passed through a 30-mesh sieve) and placed in a 200 ml glass beaker. 50 mL of tap water was then slowly added to the beaker, which was then placed in an incubator at 30 ± 5°C. The remaining weight was measured on the seventh day. The results are shown in Table 3 below.

[0035]

[0036] The following conclusions can be drawn from the test results in Tables 1 to 3 above: (1) Examples 1 to 4 show that the present invention uses biomass raw materials to construct oxidized biochar, which is then combined with carboxymethyl chitosan and oxidized to obtain aldehyde-modified oxidized biochar, which is then cross-linked with amino acids to form amino acid-modified oxidized biochar. Finally, the amino acid-modified oxidized biochar is mixed with superphosphate, stirred with water, and then dried to a constant weight to obtain an organic biological compound phosphate fertilizer, which has good phosphate fertilizer loading performance, slow release properties, and good water retention properties.

[0037] (2) It can be found from Comparative Example 1 that although high-temperature carbonization can increase the specific surface area of bio-based carbon materials, and the increase in specific surface area can increase the adsorption capacity, in this system, excessively high temperature and excessively long high-temperature carbonization may cause the structure of the bio-based carbon materials to collapse, which may in turn reduce the adsorption capacity of phosphate fertilizers, resulting in the final prepared organic biological compound phosphate fertilizer containing a low total phosphorus content and poor phosphorus loading performance. In addition, the collapse of the bio-based carbon material structure leads to poor slow-release effect and water retention performance.

[0038] (3) Comparative Example 2 shows that although the oxidation treatment of biochar materials with hydrogen peroxide can increase the number of oxygen-containing active groups on the surface, thereby increasing the reactivity of the biochar materials, in this system, it is found that the organic biological compound phosphate fertilizer finally prepared has a low total phosphorus content, poor phosphorus loading performance, and poor slow-release effect and water retention performance. This may be due to the excessively high concentration of hydrogen peroxide and the excessively long oxidation treatment time, which may lead to the destruction of the structure of the biochar material, and instead make the prepared organic biological compound phosphate fertilizer perform poorly.

[0039] (4) Comparative Example 3 shows that although chitosan also has amino and o-dihydroxy structures and can undergo subsequent condensation reactions and oxidation reactions, the total phosphorus content of the organic biological compound phosphate fertilizer prepared in this system is poor and its water retention performance is average. This may be due to the extremely poor solubility and poor hygroscopicity of chitosan, which in turn leads to the poor performance of the organic biological compound phosphate fertilizer.

[0040] (5) It can be found from Comparative Example 4 that although the prepared organic biological compound phosphate fertilizer has a good total phosphorus content, it performs poorly in terms of water retention. This may be because although carboxymethyl chitosan has good hydrophilic properties, during the oxidation process, the carbon chain structure is partially destroyed, which may weaken the hydrophilicity and lead to poor water retention performance. If it is not improved, it may lead to poor fertilizer efficiency.

[0041] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for producing an organic biological compound phosphate fertilizer, characterized in that: The production method comprises the following steps: The biomass raw materials are subjected to high-temperature carbonization treatment at 500°C to 600°C for 2h to 3h to obtain bio-based carbon materials; The bio-based carbon material is subjected to hydrogen oxidation and hydrogenation to obtain oxidized biomass carbon; The oxidized biochar and carboxymethyl chitosan are dispersed in anhydrous dichloromethane to obtain a dispersion, an acid catalyst and a water absorbent are added to the dispersion, mixed, heated to 40° C. to 50° C., reacted for 20 h to 24 h, and then filtered to obtain carboxymethyl chitosan-modified oxidized biochar; The carboxymethyl chitosan modified oxidized biochar is subjected to light-shielding oxidation treatment with an oxidant for 4 to 6 hours to obtain aldehyde-oxidized biochar; The aldehyde-modified oxidized biochar is dispersed in an amino acid aqueous solution and heated to 100° C. to 110° C. for reaction for 3 h to 5 h to obtain the amino acid-modified oxidized biochar; The amino acid modified oxidized biochar, water-soluble phosphate fertilizer and water are mixed and stirred for 2 hours to 3 hours, and then dried to obtain the organic biological compound phosphate fertilizer.

2. The method for producing an organic biological compound phosphate fertilizer according to claim 1, wherein: The conditions for the hydrogen peroxide oxidation treatment include a mass concentration of hydrogen peroxide of 30% to 40% and a treatment time of 3 hours to 4 hours.

3. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The weight ratio of the oxidized biomass charcoal: carboxymethyl chitosan: anhydrous dichloromethane is 1:3-5:200-300.

4. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The acid catalyst includes 3-quinolineboronic acid.

5. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The water absorbent includes 13X molecular sieve.

6. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The weight ratio of the dispersion liquid: the acid catalyst: the water absorbent is 1: 0.08-0.1: 0.01-0.

03.

7. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The weight ratio of the carboxymethyl chitosan modified oxidized biochar to the oxidant is 1:0.5-0.

7.

8. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The amino acid aqueous solution includes an L-lysine aqueous solution with a mass concentration of 30% or an L-arginine aqueous solution with a mass concentration of 30%.

9. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The water-soluble phosphate fertilizer includes superphosphate or triple superphosphate.

10. The method for producing an organic biological compound phosphate fertilizer according to claim 1, characterized in that: The weight ratio of the amino acid modified oxidized biochar: water-soluble phosphate fertilizer: water is 1:0.4-0.6:300-500.

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