High-salt liquid fertilizer long-acting steady-state regulator and preparation method thereof

Abstract

The present application relates to the technical field of liquid fertilizer steady-state regulator, in particular to a long-acting steady-state regulator for high-salt liquid fertilizer and a preparation method thereof, the long-acting steady-state regulator for high-salt liquid fertilizer provided by the present application realizes the double regulation of 'ion steady-state control' and 'nutrient gradient slow release' for the high-salt liquid fertilizer system through the synergistic cooperation of modified aminated graphene oxide / humic acid compound and polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres. Specifically, in the modified aminated graphene oxide / humic acid compound, the aminated graphene oxide can efficiently anchor free metal ions such as calcium, magnesium and iron in the high-salt environment through coordination chelation and hydrogen bond due to its huge specific surface area and surface grafted amino active sites, thereby effectively inhibiting the precipitation reaction of metal ions and phosphate, sulfate.

Description

Technical Field

[0001] This invention relates to the field of liquid fertilizer steady-state regulators, specifically to a long-acting steady-state regulator for high-salt liquid fertilizers and its preparation method. Background Technology

[0002] High-salt liquid fertilizers are widely used in fertigation systems due to their high nutrient concentration, good water solubility, and convenient application. However, high-salt liquid fertilizers face significant stability challenges during production, storage, transportation, and use: on the one hand, high-concentration salt ions (such as ammonium, phosphate, sulfate, and metal cations) are prone to salting out, crystallizing, and precipitating under alternating high and low temperatures, leading to fertilizer stratification and clogging of irrigation pipes; on the other hand, the organic active ingredients added to liquid fertilizers (such as humic acid and amino acids) are prone to flocculation and aggregation under high-salt and high-ionic-strength conditions, resulting in a significant reduction in effective components and severely affecting fertilizer quality.

[0003] To address the aforementioned issues, existing technologies have reported the addition of stabilizing agents such as dispersants, thickeners, or surfactants to high-salt liquid fertilizers. However, these conventional agents often rely on simple physical dispersion or electrostatic repulsion to achieve short-term stability. In high-salt systems, their effectiveness is significantly weakened by the double-layer compression effect, making long-term stability difficult to guarantee. Furthermore, existing stabilization technologies primarily focus on physical stability during storage, failing to consider the slow-release requirements of nutrients after application to the soil. This has resulted in the persistent bottleneck problem of high-salt liquid fertilizers being prone to leaching during storage and leaching after application. In addition, existing stabilizing agents lack synergistic design among their components, have limited functionality, and cannot simultaneously meet the multiple requirements of ion chelation anchoring, interfacial activity regulation, and nutrient gradient release.

[0004] Therefore, developing a steady-state regulator that can maintain long-term steady-state in high-salt environments and regulate the slow-release of nutrients after application is of great practical significance and has broad application prospects. Summary of the Invention

[0005] Technical problems to be solved To address the aforementioned shortcomings of existing technologies, this invention provides a long-acting steady-state regulator for high-salt liquid fertilizers and its preparation method, which effectively solves the problem that existing high-salt liquid fertilizer regulators cannot simultaneously maintain long-term steady-state conditions in high-salt environments and regulate nutrient slow-release after application.

[0006] Technical solution To achieve the above objectives, the present invention provides the following technical solution: A long-acting steady-state regulator for high-salt liquid fertilizer comprises the following components: modified aminated graphene oxide / humic acid complex, polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, alkylamide polyoxyethylene polyoxypropylene betaine, potassium polyphosphate, n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate. The modified aminated graphene oxide / humic acid composite is prepared by aminated graphene oxide and activated humic acid. The polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres were prepared by cross-linking reaction of polyaspartic acid and sodium alginate.

[0007] Furthermore, the preparation steps of the aminated graphene oxide are as follows: Step 1: Disperse 10-15 parts by weight of nano-graphite powder in 350-400 parts by weight of concentrated sulfuric acid solution, then add 45-60 parts by weight of potassium permanganate and stir at 10-18℃ for 2 hours. After the reaction is completed, raise the temperature to 35-37℃ and add the calculated amount of deionized water at a solid-liquid ratio of 1:5. After raising the temperature to 98℃, react for 30 minutes and add 30-50 parts by weight of 30% hydrogen peroxide to terminate the reaction. After centrifugation and washing until neutral, obtain graphene oxide slurry. Step 2: After ultrasonically dispersing the graphene oxide slurry, add 15-20 parts by weight of EDC hydrochloride and 8-12 parts by weight of N-hydroxysuccinimide. After reacting for 1 hour, add 20-30 parts by weight of ethylenediamine and react in a water bath at 60°C for 6 hours. After the reaction is complete, dialyze with deionized water for 48 hours. After freeze-drying, the obtained product is aminated graphene oxide.

[0008] Furthermore, in step 1, the mass fraction of the concentrated sulfuric acid solution is 98%, the stirring speed of the stirring reaction in step 1 is 100-200 r / min, the ultrasonic dispersion method in step 2 is ultrasonic dispersion for 30 min at a power of 500 W and a frequency of 40 kHz, and the molecular weight cutoff for dialysis in step 2 is 8000-14000 Da.

[0009] Furthermore, the activation treatment method for the humic acid is as follows: 50-60 parts by weight of weathered coal humic acid are pulverized and passed through a 200-mesh sieve, then added to 200-300 parts by weight of deionized water. The mixture is stirred at 200-300 r / min for 10 min, and then 20-25 parts by weight of 65% concentrated nitric acid are added dropwise under a water bath at 60℃. After reacting at this temperature for 2 h, the mixture is cooled to room temperature. The pH value is adjusted to 7.0 with a 10% sodium hydroxide solution, and then centrifuged at 4000-5000 r / min for 15 min. The supernatant is collected, freeze-dried, and ground to obtain the activated humic acid.

[0010] Furthermore, the preparation steps of the modified aminated graphene oxide / humic acid composite are as follows: Step a: Disperse 10-15 parts by weight of aminated graphene oxide in 100-120 parts by weight of deionized water, add 12-18 parts by weight of EDC hydrochloride and 6-10 parts by weight of N-hydroxysuccinimide, and stir and activate at room temperature for 1 hour. The resulting product is called graphene dispersion. Step b: Dissolve 30-45 parts by weight in deionized water to prepare an activated humic acid solution with a mass fraction of 5%. Pour the solution into the graphene dispersion and stir at room temperature for 24 hours. After the reaction is complete, filter the solution through a 0.22 μm filter membrane. Then wash the solution three times with deionized water and three times with anhydrous ethanol. After vacuum drying and grinding through a 300-mesh sieve, the resulting product is the modified aminated graphene oxide / humic acid composite.

[0011] Furthermore, the stirring speed for activation in step a is 200-300 r / min, the stirring speed for reaction in step b is 300-500 r / min, and the vacuum drying method in step b is to dry in a vacuum drying oven at 50°C until constant weight.

[0012] Furthermore, the preparation steps of the polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres are as follows: Step I: Weigh 10-20 parts by weight of polyaspartic acid and 8-15 parts by weight of sodium alginate and dissolve them in 100-200 parts by weight of deionized water. Stir at room temperature for 2 hours and let stand to remove bubbles to obtain the aqueous phase component. Add 10-20 parts by weight of Span 80 to 300-500 parts by weight of liquid paraffin and stir to mix evenly to obtain the oil phase component. Step II: Heat the oil phase component to 40-42℃ in a water bath and add the aqueous phase component dropwise under stirring. After the dropwise addition is complete, continue stirring for 15 minutes to form a water-in-oil emulsion. Then, add 5-10 parts by weight of a 10% calcium chloride solution for ionic crosslinking and 2-5 parts by weight of glutaraldehyde for chemical crosslinking. The mixture is then kept at 40℃ for 3 hours and the resulting product is recorded as the reaction product component. Step III: Wash the reaction product components three times with acetone and deionized water alternately, and dry them in a vacuum drying oven at 30°C for 12 hours to obtain polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres.

[0013] Furthermore, in step I, the stirring speed at room temperature is 200-300 r / min, and the method for mixing evenly in step I is to stir at a stirring speed of 400-500 r / min for 30 min. In step II, the stirring speed is 200-300 r / min.

[0014] A method for preparing a long-acting steady-state regulator for high-salt liquid fertilizer, wherein the preparation method comprises: Step 1: Weigh 0.5-1.5 parts by weight of n-butylthiophosphoric triamine and 1-2.5 parts by weight of 3,4-dimethylpyrazole phosphate, mix them, and disperse them evenly. The resulting mixture is called the compound. Step 2: Weigh 5-15 parts by weight of modified aminated graphene oxide / humic acid complex, 10-25 parts by weight of polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, 3-8 parts by weight of alkylamide polyoxyethylene polyoxypropylene betaine, 2-5 parts by weight of potassium polyphosphate, and mix with the compound in Step 1. After uniform dispersion, pulverize and pass through a 200-mesh sieve. The result is a long-term stable regulator for high-salt liquid fertilizer.

[0015] Furthermore, the method for achieving uniform dispersion in both Step 1 and Step 2 is to stir at a stirring speed of 200-300 r / min for 30 min.

[0016] Beneficial effects This invention provides a long-acting steady-state regulator for high-salt liquid fertilizers and its preparation method. Compared with existing technologies, this invention has the following advantages: 1. The long-acting steady-state regulator for high-salt liquid fertilizers provided by this invention achieves dual regulation of "ion steady-state control" and "nutrient gradient slow release" in high-salt liquid fertilizer systems through the synergistic effect of modified aminated graphene oxide / humic acid composite and polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres. Specifically, in the modified aminated graphene oxide / humic acid composite, the aminated graphene oxide, with its huge specific surface area and surface-grafted amino active sites, can efficiently anchor free metal ions (such as calcium, magnesium, iron, etc.) in high-salt environments through coordination chelation and hydrogen bonding, effectively inhibiting the precipitation reaction of metal ions with phosphate and sulfate ions; at the same time, activated humic acid is bonded to the surface of graphene oxide through amidation, and its abundant carboxyl and phenolic hydroxyl groups further enhance the affinity of the composite for nutrient ions, and the colloidal dispersion characteristics of humic acid itself can synergistically inhibit the precipitation and crystallization of salts.

[0017] Building upon this foundation, polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres serve as an independent slow-release framework. Their unique interpenetrating network structure endows the microspheres with excellent mechanical strength and ionic response. When the external high-salt environment leads to increased ionic strength, the microsphere network contracts, slowing the leakage of internally encapsulated nutrients. Conversely, when the fertilizer is diluted or applied to the soil, the microspheres absorb water, swell, and gradually release nutrients. More importantly, the polyaspartic acid within the interpenetrating network hydrogel microspheres possesses excellent chelating and dispersing capabilities. It forms a "spatially complementary" steady-state effect with the modified aminated graphene oxide / humic acid complex: the complex focuses on immediate anchoring of free ions and inhibition of crystal nuclei, while the hydrogel microspheres focus on nutrient encapsulation and ionic strength buffering. This combined effect effectively prevents precipitation and stratification of high-salt liquid fertilizers during storage, while also providing dual protection for prolonged fertilizer efficacy after application to the soil.

[0018] 2. This invention, through the precise compounding of organic small-molecule stabilizing adjuvants with the aforementioned functional macromolecular materials, further stimulates a significant multi-component synergistic effect. Alkylamide polyoxyethylene polyoxypropylene betaine, as an amphoteric surfactant, can reduce the interfacial tension of high-salt systems and improve the dispersion uniformity of each component in liquid fertilizer. Furthermore, the amide groups and polyoxyethylene segments in its molecular structure can form secondary bonds with the polar groups on the surface of the modified aminated graphene oxide / humic acid complex, assisting the complex in forming a more stable three-dimensional spatial network distribution in the liquid phase and preventing the aggregation and sedimentation of functional particles. The introduction of potassium polyphosphate plays multiple synergistic roles: as a buffer, potassium polyphosphate can stabilize the pH value of high-salt liquid fertilizer systems, avoiding humic acid flocculation or metal ion hydrolysis precipitation caused by pH fluctuations; as a synergistic phosphorus source, the gradual hydrolysis of polyphosphate ions can provide crops with long-term phosphorus replenishment, matching the slow-release characteristics of hydrogel microspheres to form a synergistic fertilizer supply pattern of "slow-release phosphorus + slow-release nitrogen".

[0019] Furthermore, the combination of n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate acts on the active sites of urease and nitrification enzymes, respectively, inhibiting the hydrolysis loss of urea nitrogen and the nitrification leaching of ammonium nitrogen at the biochemical level. The timing of their action perfectly complements the physical slow-release rhythm of the hydrogel microspheres, creating a "chemical-biochemical-physical inhibition" time-response relationship. That is, while the microspheres slow down the nutrient release rate, the urease inhibitor and nitrification inhibitor prolong the retention time of released nutrients in the soil. This tiered effect significantly improves the effective utilization rate of fertilizer nitrogen. The aforementioned components work closely together at multiple levels, including steric stabilization, ion chelation anchoring, interfacial activity regulation, pH buffering maintenance, and enzyme activity inhibition. Together, they endow this steady-state regulator with excellent stability and long-term regulatory capacity throughout the entire lifecycle under high-salt extreme environments. This represents a significant advancement in solving the common technical challenges in the industry of high-salt liquid fertilizers, such as easy precipitation during storage and short-term effectiveness after application to the soil. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] The present invention will be further described below with reference to embodiments.

[0022] Example 1

[0023] This embodiment of a high-salt liquid fertilizer long-acting steady-state regulator includes the following components: modified aminated graphene oxide / humic acid complex, polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, alkylamide polyoxyethylene polyoxypropylene betaine, potassium polyphosphate, n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate. The modified aminated graphene oxide / humic acid composite is prepared by aminated graphene oxide and activated humic acid. The preparation steps for aminated graphene oxide are as follows: Step 1: Disperse 10 parts by weight of nano-graphite powder in 350 parts by weight of concentrated sulfuric acid solution with a mass fraction of 98%. Then add 45 parts by weight of potassium permanganate and stir at 100 r / min for 2 hours at 10°C. After the reaction is completed, raise the temperature to 35°C and add the calculated amount of deionized water at a solid-liquid ratio of 1:5. After raising the temperature to 98°C, react for 30 minutes and add 50 parts by weight of hydrogen peroxide with a mass fraction of 30% to terminate the reaction. After centrifugation and washing until neutral, obtain graphene oxide slurry. Step 2: After ultrasonically dispersing the graphene oxide slurry at a power of 500W and a frequency of 40kHz for 30 minutes, add 15 parts by weight of EDC hydrochloride and 8 parts by weight of N-hydroxysuccinimide. After reacting for 1 hour, add 20 parts by weight of ethylenediamine and react in a water bath at 60℃ for 6 hours. After the reaction is completed, dialyze with deionized water for 48 hours (the molecular weight cutoff is 8000-14000Da). After freeze-drying, the obtained product is aminated graphene oxide.

[0024] The activation treatment method for humic acid is as follows: 50 parts by weight of weathered coal humic acid were pulverized and passed through a 200-mesh sieve, then added to 200 parts by weight of deionized water. The mixture was stirred at 200 r / min for 10 min, and then 20 parts by weight of 65% concentrated nitric acid were added dropwise under a water bath at 60℃. After reacting at this temperature for 2 h, the mixture was cooled to room temperature. The pH value was adjusted to 7.0 with a 10% sodium hydroxide solution, and then the mixture was centrifuged at 4000 r / min for 15 min. The supernatant was collected, freeze-dried, and ground to obtain the activated humic acid.

[0025] The preparation steps of the modified aminated graphene oxide / humic acid composite are as follows: Step a: Disperse 10 parts by weight of aminated graphene oxide in 100 parts by weight of deionized water, add 12 parts by weight of EDC hydrochloride and 6 parts by weight of N-hydroxysuccinimide, and then stir and activate at room temperature at a stirring speed of 200 r / min for 1 h. The resulting product is called graphene dispersion. Step b: Dissolve 30 parts by weight in deionized water to prepare an activated humic acid solution with a mass fraction of 5%. Pour the solution into the graphene dispersion and stir at 300 r / min at room temperature for 24 h. After the reaction is complete, filter the solution through a 0.22 μm filter membrane. Then wash the solution three times with deionized water and anhydrous ethanol, respectively. Dry the solution in a vacuum drying oven at 50 °C until constant weight and grind it through a 300 mesh sieve. The result is the modified aminated graphene oxide / humic acid composite.

[0026] The polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres were prepared by cross-linking polyaspartic acid and sodium alginate as raw materials. The preparation steps are as follows: Step I: Weigh 10 parts by weight of polyaspartic acid and 8 parts by weight of sodium alginate and dissolve them in 100 parts by weight of deionized water. Stir at room temperature for 2 hours at a stirring speed of 200 r / min and let stand to remove bubbles to obtain the aqueous phase component. Add 10 parts by weight of Span 80 to 300 parts by weight of liquid paraffin and stir at a stirring speed of 400 r / min for 30 minutes to obtain the oil phase component. Step II: After heating the oil phase component to 40°C in a water bath, add the aqueous phase component dropwise while stirring at a speed of 200 r / min. After the addition is complete, continue stirring for 15 min to form a water-in-oil emulsion. Then, add 5 parts by weight of a 10% calcium chloride solution for ionic crosslinking and 2 parts by weight of glutaraldehyde for chemical crosslinking. The mixture is then kept at 40°C for 3 h and the resulting product is recorded as the reaction product component. Step III: Wash the reaction product components three times alternately with acetone and deionized water, and dry them in a vacuum drying oven at 30°C for 12 hours to obtain polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres.

[0027] A method for preparing a long-acting steady-state regulator for high-salt liquid fertilizer, the preparation method being as follows: Step 1: Weigh 0.5 parts by weight of n-butylthiophosphoric triamine and 1 part by weight of 3,4-dimethylpyrazole phosphate and mix them. Stir at 200 r / min for 30 min. The resulting mixture is called the compound. Step 2: Weigh 5 parts by weight of modified aminated graphene oxide / humic acid composite, 10 parts by weight of polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, 3 parts by weight of alkylamide polyoxyethylene polyoxypropylene betaine, 2 parts by weight of potassium polyphosphate and the compound from Step 1, mix them, stir at 200 r / min for 30 min, then pulverize and pass through a 200 mesh sieve. The result is the long-term stable regulator of high-salt liquid fertilizer.

[0028] Example 2

[0029] This embodiment of a high-salt liquid fertilizer long-acting steady-state regulator includes the following components: modified aminated graphene oxide / humic acid complex, polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, alkylamide polyoxyethylene polyoxypropylene betaine, potassium polyphosphate, n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate. The modified aminated graphene oxide / humic acid composite is prepared by aminated graphene oxide and activated humic acid. The preparation steps for aminated graphene oxide are as follows: Step 1: Disperse 13 parts by weight of nano-graphite powder in 380 parts by weight of concentrated sulfuric acid solution with a mass fraction of 98%. Then add 52 parts by weight of potassium permanganate and stir at 200 r / min for 2 hours at 14°C. After the reaction is completed, raise the temperature to 36°C and add the calculated amount of deionized water at a solid-liquid ratio of 1:5. After raising the temperature to 98°C, react for 30 minutes and add 40 parts by weight of hydrogen peroxide with a mass fraction of 30% to terminate the reaction. After centrifugation and washing until neutral, obtain graphene oxide slurry. Step 2: After ultrasonically dispersing the graphene oxide slurry at a power of 500W and a frequency of 40kHz for 30 minutes, add 18 parts by weight of EDC hydrochloride and 10 parts by weight of N-hydroxysuccinimide. After reacting for 1 hour, add 25 parts by weight of ethylenediamine and react in a water bath at 60℃ for 6 hours. After the reaction is completed, dialyze with deionized water for 48 hours (the molecular weight cutoff is 8000-14000Da). After freeze-drying, the obtained product is aminated graphene oxide.

[0030] The activation treatment method for humic acid is as follows: 55 parts by weight of weathered coal humic acid were pulverized and passed through a 200-mesh sieve, then added to 300 parts by weight of deionized water. The mixture was stirred at 200 r / min for 10 min, and then 22 parts by weight of 65% concentrated nitric acid were added dropwise under a water bath at 60℃. After reacting at this temperature for 2 h, the mixture was cooled to room temperature. The pH value was adjusted to 7.0 with a 10% sodium hydroxide solution, and then the mixture was centrifuged at 5000 r / min for 15 min. The supernatant was collected, freeze-dried, and ground to obtain the activated humic acid.

[0031] The preparation steps of the modified aminated graphene oxide / humic acid composite are as follows: Step a: Disperse 13 parts by weight of aminated graphene oxide in 110 parts by weight of deionized water, add 15 parts by weight of EDC hydrochloride and 8 parts by weight of N-hydroxysuccinimide, and then stir and activate at room temperature at a stirring speed of 300 r / min for 1 h. The resulting product is called graphene dispersion. Step b: Dissolve 38 parts by weight in deionized water to prepare an activated humic acid solution with a mass fraction of 5%. Pour the solution into the graphene dispersion and stir at 400 r / min at room temperature for 24 h. After the reaction is complete, filter the solution through a 0.22 μm filter membrane. Then wash the solution three times with deionized water and anhydrous ethanol respectively. Dry the solution in a vacuum drying oven at 50 °C until constant weight and grind it through a 300 mesh sieve. The result is the modified aminated graphene oxide / humic acid composite.

[0032] The polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres were prepared by cross-linking polyaspartic acid and sodium alginate as raw materials. The preparation steps are as follows: Step I: Weigh 15 parts by weight of polyaspartic acid and 12 parts by weight of sodium alginate and dissolve them in 150 parts by weight of deionized water. Stir at room temperature for 2 hours at a stirring speed of 300 r / min and let stand to remove bubbles to obtain the aqueous phase component. Add 15 parts by weight of Span 80 to 400 parts by weight of liquid paraffin and stir at a stirring speed of 500 r / min for 30 minutes to obtain the oil phase component. Step II: After heating the oil phase component to 41°C in a water bath, add the aqueous phase component dropwise while stirring at 300 r / min. After the dropwise addition is complete, continue stirring for 15 min to form a water-in-oil emulsion. Then, add 8 parts by weight of a 10% calcium chloride solution for ionic crosslinking and 3 parts by weight of glutaraldehyde for chemical crosslinking. The mixture is then reacted at 40°C for 3 h. The resulting product is recorded as the reaction product component. Step III: Wash the reaction product components three times alternately with acetone and deionized water, and dry them in a vacuum drying oven at 30°C for 12 hours to obtain polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres.

[0033] A method for preparing a long-acting steady-state regulator for high-salt liquid fertilizer, the preparation method being as follows: Step 1: Weigh 1 part by weight of n-butylthiophosphoric triamine and 1.8 parts by weight of 3,4-dimethylpyrazole phosphate and mix them. Stir at 300 r / min for 30 min. The resulting mixture is called the compound. Step 2: Weigh 10 parts by weight of modified aminated graphene oxide / humic acid composite, 17 parts by weight of polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, 5 parts by weight of alkylamide polyoxyethylene polyoxypropylene betaine, 4 parts by weight of potassium polyphosphate and the compound in Step 1 and mix them. Stir at 300 r / min for 30 min and then pulverize and pass through a 200 mesh sieve. The result is the long-term stable regulator of high-salt liquid fertilizer.

[0034] Example 3

[0035] This embodiment of a high-salt liquid fertilizer long-acting steady-state regulator includes the following components: modified aminated graphene oxide / humic acid complex, polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, alkylamide polyoxyethylene polyoxypropylene betaine, potassium polyphosphate, n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate. The modified aminated graphene oxide / humic acid composite is prepared by aminated graphene oxide and activated humic acid. The preparation steps for aminated graphene oxide are as follows: Step 1: Disperse 15 parts by weight of nano-graphite powder in 400 parts by weight of concentrated sulfuric acid solution with a mass fraction of 98%. Then add 60 parts by weight of potassium permanganate and stir at 200 r / min for 2 hours at 18°C. After the reaction is completed, raise the temperature to 37°C and add the calculated amount of deionized water at a solid-liquid ratio of 1:5. After raising the temperature to 98°C, react for 30 minutes and add 50 parts by weight of hydrogen peroxide with a mass fraction of 30% to terminate the reaction. After centrifugation and washing until neutral, obtain graphene oxide slurry. Step 2: After ultrasonically dispersing the graphene oxide slurry at a power of 500W and a frequency of 40kHz for 30 minutes, add 20 parts by weight of EDC hydrochloride and 12 parts by weight of N-hydroxysuccinimide. After reacting for 1 hour, add 30 parts by weight of ethylenediamine and react in a water bath at 60℃ for 6 hours. After the reaction is completed, dialyze with deionized water for 48 hours (the molecular weight cutoff is 8000-14000Da). After freeze-drying, the obtained product is aminated graphene oxide.

[0036] The activation treatment method for humic acid is as follows: 60 parts by weight of weathered coal humic acid were pulverized and passed through a 200-mesh sieve, then added to 300 parts by weight of deionized water. The mixture was stirred at 300 r / min for 10 min, and then 25 parts by weight of 65% concentrated nitric acid were added dropwise under a water bath at 60℃. After reacting at this temperature for 2 h, the mixture was cooled to room temperature. The pH value was adjusted to 7.0 with a 10% sodium hydroxide solution, and then the mixture was centrifuged at 5000 r / min for 15 min. The supernatant was collected, freeze-dried, and ground to obtain the activated humic acid.

[0037] The preparation steps of the modified aminated graphene oxide / humic acid composite are as follows: Step a: Disperse 15 parts by weight of aminated graphene oxide in 120 parts by weight of deionized water, add 18 parts by weight of EDC hydrochloride and 10 parts by weight of N-hydroxysuccinimide, and then stir and activate at room temperature at a stirring speed of 300 r / min for 1 h. The resulting product is called graphene dispersion. Step b: Dissolve 45 parts by weight in deionized water to prepare an activated humic acid solution with a mass fraction of 5%. Pour the solution into the graphene dispersion and stir at 500 r / min at room temperature for 24 h. After the reaction is complete, filter the solution through a 0.22 μm filter membrane. Then wash the solution three times with deionized water and anhydrous ethanol respectively. Dry the solution in a vacuum drying oven at 50 °C until constant weight and grind it through a 300 mesh sieve. The result is the modified aminated graphene oxide / humic acid composite.

[0038] The polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres were prepared by cross-linking polyaspartic acid and sodium alginate as raw materials. The preparation steps are as follows: Step 1: Weigh 20 parts by weight of polyaspartic acid and 15 parts by weight of sodium alginate and dissolve them in 200 parts by weight of deionized water. Stir at room temperature for 2 hours at a stirring speed of 300 r / min and let stand to remove bubbles to obtain the aqueous phase component. Add 20 parts by weight of Span 80 to 500 parts by weight of liquid paraffin and stir at a stirring speed of 500 r / min for 30 minutes to obtain the oil phase component. Step II: After heating the oil phase component to 42°C in a water bath, add the aqueous phase component dropwise while stirring at 300 r / min. After the dropwise addition is complete, continue stirring for 15 min to form a water-in-oil emulsion. Then, add 10 parts by weight of a 10% calcium chloride solution for ionic crosslinking and 5 parts by weight of glutaraldehyde for chemical crosslinking. The mixture is then reacted at a constant temperature of 40°C for 3 h. The resulting product is recorded as the reaction product component. Step III: Wash the reaction product components three times with acetone and deionized water alternately, and dry them in a vacuum drying oven at 30°C for 12 hours to obtain polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres.

[0039] A method for preparing a long-acting steady-state regulator for high-salt liquid fertilizer, the preparation method being as follows: Step 1: Weigh 1.5 parts by weight of n-butylthiophosphoric triamine and 2.5 parts by weight of 3,4-dimethylpyrazole phosphate and mix them. Stir at 300 r / min for 30 min. The resulting mixture is called the compound. Step 2: Weigh 15 parts by weight of modified aminated graphene oxide / humic acid composite, 25 parts by weight of polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, 8 parts by weight of alkylamide polyoxyethylene polyoxypropylene betaine, 5 parts by weight of potassium polyphosphate and the compound from Step 1 and mix them. Stir at 300 r / min for 30 min and then pulverize and pass through a 200 mesh sieve. The result is the long-term stable regulator of high-salt liquid fertilizer.

[0040] Comparative Example 1 The long-acting steady-state regulator for high-salt liquid fertilizer and its preparation method provided in this comparative example are largely the same as those in Example 1. The main difference is that the aminated graphene oxide in Example 1 is replaced with graphene oxide in this comparative example.

[0041] Comparative Example 2 The long-acting steady-state regulator for high-salt liquid fertilizer and its preparation method provided in this comparative example are largely the same as those in Example 1. The main difference is that the modified aminated graphene oxide / humic acid complex in Example 1 is replaced with humic acid.

[0042] Comparative Example 3 The long-acting steady-state regulator for high-salt liquid fertilizer and its preparation method provided in this comparative example are largely the same as those in Example 1. The main difference is that the polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres in Example 1 are replaced with polyaspartic acid.

[0043] Performance testing The long-acting steady-state regulators of high-salt liquid fertilizers prepared in Examples 1-3 and Comparative Examples 1-3 were labeled as Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3, respectively. The performance of Examples 1-3 and Comparative Examples 1-3 was then tested, and the data obtained are recorded in the table below.

[0044] The data in the table above shows that the insoluble matter content of Examples 1-3 after 30 days of storage at 54℃ was only 19-28 mg / L, while that of Comparative Examples 1-3 was as high as 86-135 mg / L. In terms of the amount of bottom crystallization after storage at -5℃, the amount of crystallization in Examples 1-3 was only 0.5-0.8 g / L, which was significantly lower than that of the Comparative Examples of 3.2-5.8 g / L. This indicates that the present invention, through the synergistic effect of the ion anchoring effect of the modified aminated graphene oxide / humic acid composite and the ion strength buffering effect of the hydrogel microspheres, greatly inhibits the salt leaching and ion precipitation in high-salt liquid fertilizers, and achieves long-term steady-state maintenance under alternating high and low temperature environments.

[0045] The calcium ion chelating capacity of Examples 1-3 was as high as 218-251 mg Ca. 2+ / g, while Comparative Example 1 only had 142mg Ca 2+ / g, compared to only 98mg Ca in Comparative Example 2. 2+ / g, Comparative Example 3 was 156mg Ca 2+ / g. These results indicate that the amylation grafting of graphene oxide significantly increases the density of active chelating sites, and the composite structure formed by its association with activated humic acid via amidation further enhances the overall chelating capacity, providing structural assurance for the effective anchoring of metal ions under high-salt conditions.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A long-acting steady-state regulator for high-salt liquid fertilizers, characterized in that, It includes the following components: modified aminated graphene oxide / humic acid complex, polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, alkylamide polyoxyethylene polyoxypropylene betaine, potassium polyphosphate, n-butylthiophosphoric triamine and 3,4-dimethylpyrazole phosphate. The modified aminated graphene oxide / humic acid composite is prepared by aminated graphene oxide and activated humic acid. The polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres were prepared by cross-linking reaction of polyaspartic acid and sodium alginate.

2. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 1, characterized in that, The preparation steps of the aminated graphene oxide are as follows: Step 1: Disperse 10-15 parts by weight of nano-graphite powder in 350-400 parts by weight of concentrated sulfuric acid solution, then add 45-60 parts by weight of potassium permanganate and stir at 10-18℃ for 2 hours. After the reaction is completed, raise the temperature to 35-37℃ and add the calculated amount of deionized water at a solid-liquid ratio of 1:

5. After raising the temperature to 98℃, react for 30 minutes and add 30-50 parts by weight of 30% hydrogen peroxide to terminate the reaction. After centrifugation and washing until neutral, obtain graphene oxide slurry. Step 2: After ultrasonically dispersing the graphene oxide slurry, add 15-20 parts by weight of EDC hydrochloride and 8-12 parts by weight of N-hydroxysuccinimide. After reacting for 1 hour, add 20-30 parts by weight of ethylenediamine and react in a water bath at 60°C for 6 hours. After the reaction is complete, dialyze with deionized water for 48 hours. After freeze-drying, the obtained product is aminated graphene oxide.

3. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 2, characterized in that, In step 1, the mass fraction of the concentrated sulfuric acid solution is 98%. The stirring speed of the stirring reaction in step 1 is 100-200 r / min. In step 2, the ultrasonic dispersion method is ultrasonic dispersion for 30 min at a power of 500 W and a frequency of 40 kHz. The molecular weight cutoff for dialysis in step 2 is 8000-14000 Da.

4. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 1, characterized in that, The activation treatment method for the humic acid is as follows: 50-60 parts by weight of weathered coal humic acid are pulverized and passed through a 200-mesh sieve, then added to 200-300 parts by weight of deionized water. The mixture is stirred at 200-300 r / min for 10 min, and then 20-25 parts by weight of 65% concentrated nitric acid are added dropwise under a water bath at 60℃. After reacting at this temperature for 2 h, the mixture is cooled to room temperature. The pH value is adjusted to 7.0 with a 10% sodium hydroxide solution, and then centrifuged at 4000-5000 r / min for 15 min. The supernatant is collected, freeze-dried, and ground to obtain the activated humic acid.

5. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 1, characterized in that, The preparation steps of the modified aminated graphene oxide / humic acid composite are as follows: Step a: Disperse 10-15 parts by weight of aminated graphene oxide in 100-120 parts by weight of deionized water, add 12-18 parts by weight of EDC hydrochloride and 6-10 parts by weight of N-hydroxysuccinimide, and stir and activate at room temperature for 1 hour. The resulting product is called graphene dispersion. Step b: Dissolve 30-45 parts by weight in deionized water to prepare an activated humic acid solution with a mass fraction of 5%. Pour the solution into the graphene dispersion and stir at room temperature for 24 hours. After the reaction is complete, filter the solution through a 0.22 μm filter membrane. Then wash the solution three times with deionized water and three times with anhydrous ethanol. After vacuum drying and grinding through a 300-mesh sieve, the resulting product is the modified aminated graphene oxide / humic acid composite.

6. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 5, characterized in that, The stirring speed for activation in step a is 200-300 r / min, the stirring speed for reaction in step b is 300-500 r / min, and the vacuum drying method in step b is to dry in a vacuum drying oven at 50℃ until constant weight.

7. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 1, characterized in that, The preparation steps of the polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres are as follows: Step I: Weigh 10-20 parts by weight of polyaspartic acid and 8-15 parts by weight of sodium alginate and dissolve them in 100-200 parts by weight of deionized water. Stir at room temperature for 2 hours and let stand to remove bubbles to obtain the aqueous phase component. Add 10-20 parts by weight of Span 80 to 300-500 parts by weight of liquid paraffin and stir to mix evenly to obtain the oil phase component. Step II: Heat the oil phase component to 40-42℃ in a water bath and add the aqueous phase component dropwise under stirring. After the dropwise addition is complete, continue stirring for 15 minutes to form a water-in-oil emulsion. Then, add 5-10 parts by weight of a 10% calcium chloride solution for ionic crosslinking and 2-5 parts by weight of glutaraldehyde for chemical crosslinking. The mixture is then kept at 40℃ for 3 hours and the resulting product is recorded as the reaction product component. Step III: Wash the reaction product components three times alternately with acetone and deionized water, and dry them in a vacuum drying oven at 30°C for 12 hours to obtain polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres.

8. The long-acting steady-state regulator for high-salt liquid fertilizer according to claim 7, characterized in that, In step I, the stirring speed at room temperature is 200-300 r / min. The method for mixing evenly in step I is to stir at a stirring speed of 400-500 r / min for 30 min. In step II, the stirring speed is 200-300 r / min.

9. A method for preparing a long-acting steady-state regulator for high-salt liquid fertilizer according to any one of claims 1-8, characterized in that, The preparation method is as follows: Step 1: Weigh 0.5-1.5 parts by weight of n-butylthiophosphoric triamine and 1-2.5 parts by weight of 3,4-dimethylpyrazole phosphate, mix them, and disperse them evenly. The resulting mixture is called the compound. Step 2: Weigh 5-15 parts by weight of modified aminated graphene oxide / humic acid complex, 10-25 parts by weight of polyaspartic acid / sodium alginate interpenetrating network hydrogel microspheres, 3-8 parts by weight of alkylamide polyoxyethylene polyoxypropylene betaine, 2-5 parts by weight of potassium polyphosphate, and mix with the compound in Step 1. After uniform dispersion, pulverize and pass through a 200-mesh sieve. The result is a long-term stable regulator for high-salt liquid fertilizer.

10. The preparation method of a long-acting steady-state regulator for high-salt liquid fertilizer according to claim 9, characterized in that, The method for achieving uniform dispersion in both Step 1 and Step 2 is to stir at a stirring speed of 200-300 r / min for 30 min.

Images