Preparation method of metal ion bridged fulvic acid-polypeptide ternary composite material

Abstract

The invention provides a preparation method of a metal ion bridged fulvic acid-polypeptide ternary composite material, and relates to the field of fertilizers, and the preparation method comprises the following steps: S1, preparing a fulvic acid solution; s2, preparing a polypeptide solution: dissolving polypeptide in a buffer solution, and stirring to prepare the polypeptide solution; s3, preparing a metal ion solution: adding metal salt into a second solvent, and stirring to prepare a metal salt solution; s4, under the stirring condition, the metal salt solution is added into the fulvic acid solution for a reaction, and a composite solution is formed; s5, adding a polypeptide solution into the composite solution under a stirring condition to obtain a mixed solution; s6, carrying out centrifugal separation on the mixed solution, collecting the precipitate, and washing the precipitate; and step S7, performing vacuum drying on the washed precipitate to obtain the metal ion bridged fulvic acid-polypeptide ternary composite material. According to the invention, a three-dimensional network structure is constructed through bridging of metal ions, so that the composite material is more stable in soil acid-base and microbial environments.

Description

Technical Field

[0001] The present invention relates to the technical field of fertilizers, in particular to a method for preparing a metal ion-bridged fulvic acid-polypeptide ternary composite material. Background Art

[0002] Fulvic acid, the smallest and most active component of humic acid, is considered the essence of humic acid's active ingredients. In agricultural production, fulvic acid can be used as a plant growth regulator to promote plant growth.

[0003] Peptides are compounds composed of three or more amino acid molecules linked by peptide bonds. They sit between large proteins and small amino acids, and possess high activity and absorbability. In agriculture and biology, peptides also demonstrate unique advantages, such as promoting plant growth and development and enhancing plant immunity.

[0004] Fulvic acid and polypeptides are used in the preparation of existing fertilizers (such as CN106146151A granular fertilizer additive and its preparation method, granular fertilizer additive powder and granular fertilizer); fulvic acid and polypeptides are simply physically mixed, and simple physical mixing only physically disperses them, which cannot amplify biological activity through intermolecular synergy, and the stability is poor due to the lack of chemical constraints.

[0005] Metal ions (such as transition metal ions zinc ions, copper ions, ferrous ions, etc.) have unique coordination capabilities and can react with specific functional groups in fulvic acid and polypeptides to form stable bridging structures. Fulvic acid molecules contain functional groups such as carboxyl, hydroxyl, and phenolic hydroxyl groups, and polypeptide molecules have active groups such as amino and carboxyl groups. Metal ions act as "molecular bridges" to connect fulvic acid and polypeptide molecules through coordination bonds to construct a three-dimensional network structure. Compared with the simple physical mixing of fulvic acid-polypeptide system, this structure has significantly improved physical and chemical stability. In complex environments (such as soil solutions with different pH values ​​and variable temperature conditions), component separation and structural collapse are not likely to occur, ensuring the continued function of the material. Summary of the Invention

[0006] The present invention provides a method for preparing a metal ion-bridged fulvic acid-polypeptide ternary composite material, which is used to solve at least one of the problems raised in the above-mentioned background art: the application of fulvic acid and polypeptides in the preparation of existing fertilizers (such as CN106146151A granular fertilizer additive and its preparation method, granular fertilizer additive powder and granular fertilizer); simple physical mixing of fulvic acid and polypeptide, which only physically disperses and cannot amplify biological activity through intermolecular synergy, and has poor stability due to the lack of chemical constraints.

[0007] In order to solve the above technical problems, the present invention discloses a method for preparing a metal ion-bridged fulvic acid-polypeptide ternary composite material, comprising:

[0008] Step S1: preparing a fulvic acid solution: adding fulvic acid to a first solvent and stirring to prepare a fulvic acid solution;

[0009] Step S2: Preparation of polypeptide solution: dissolving the polypeptide in a buffer solution and stirring to prepare a polypeptide solution;

[0010] Step S3: preparing a metal ion solution: adding a metal salt to a second solvent and stirring to prepare a metal salt solution;

[0011] Step S4: adding the metal salt solution to the fulvic acid solution under stirring to react and form a composite solution;

[0012] Step S5: adding the polypeptide solution to the composite solution under stirring to obtain a mixed solution;

[0013] Step S6: centrifuging the mixed solution, collecting the precipitate, and washing the precipitate;

[0014] Step S7: The washed precipitate is vacuum dried to obtain a metal ion-bridged fulvic acid-polypeptide ternary composite material.

[0015] Preferably, the first solvent is deionized water, and fulvic acid is added to the first solvent at a mass volume ratio of 1:20 to 1:30 (g:mL).

[0016] Preferably, the polypeptide is a plant-derived polypeptide or an animal-derived polypeptide, and the polypeptide is dissolved in a buffer solution at a mass-to-volume ratio of 1:80 to 1:150 (g:mL), and the buffer solution is a phosphate buffer solution.

[0017] Preferably, the second solvent is deionized water, and the concentration of the metal salt solution is 0.2-0.8 mol / L.

[0018] Preferably, the polypeptide solution is added dropwise to the composite solution at a speed of 3 to 8 mL / min.

[0019] Preferably, the following steps are performed before performing step S4 in batches:

[0020] Step S41: obtaining a reaction time-standard value fitting curve of each core parameter of the reaction solution under corresponding standard conditions during the process of forming a composite solution by reacting the current metal salt solution and the current fulvic acid solution, and dividing each fitting curve into a plurality of first segments according to the change rate of the corresponding parameter;

[0021] Step S42: obtaining a plurality of auxiliary standard curves, wherein the auxiliary standard curves are fitting curves of reaction time and core parameter value of each core parameter of the reaction solution under corresponding standard conditions during the process of the reaction between the current metal salt solution and the current fulvic acid solution to form a composite solution;

[0022] Step S43: performing a reaction test on the current batch of metal salt solution and the current batch of fulvic acid solution under corresponding standard conditions, repeatedly detecting actual core parameters of the reaction solution during the reaction test, and constructing a reaction time-reaction solution core parameter value fitting curve for each reaction solution core parameter; dividing the reaction time-reaction solution core parameter value fitting curve for each reaction solution core parameter into second segments corresponding one-to-one to the corresponding first segments;

[0023] Step S44: determining the actual deviation coefficient of each core parameter corresponding to each second segment and the change state matching coefficient of the two associated core parameters based on the first segment and the second segment;

[0024] Step S45: Based on step S44, a target auxiliary standard curve is selected from the auxiliary standard curves obtained in step S42;

[0025] Step S46: Determine the target drop rate for the current batch of metal salt solution and the current batch of fulvic acid solution in step S4 based on the target auxiliary standard curve.

[0026] Preferably, the core parameters include: conductivity, ultraviolet absorbance;

[0027] The difference between the maximum conductivity change rate and the minimum conductivity change rate in each first segment of the reaction time-reaction liquid conductivity standard value fitting curve corresponding to the conductivity is less than the corresponding preset difference;

[0028] The corresponding standard conditions are: the median of the corresponding standard stirring speed range and the median of the standard addition speed range of the metal salt solution;

[0029] The corresponding reaction times of the first segment and the second segment are the same.

[0030] Preferably, the washed precipitate is spread on a placement tray and dried in a vacuum drying chamber, and a nitrogen gas flow containing CO2 is sprayed toward the porous structure of the placement tray, a nitrogen gas inlet pipe is provided in the vacuum drying chamber, and a valve is provided in the nitrogen gas inlet pipe;

[0031] Step S7 includes:

[0032] Step S71: Obtain the target range of each key parameter of the corresponding type of precipitation in each drying section of the current batch of precipitation and the standard concentration of CO2 in the CO2-containing nitrogen gas flow, the key parameters including: room temperature in the drying chamber and vacuum degree in the drying chamber;

[0033] Step S72: determining a fitting curve of drying time-reference precipitate humidity in each drying section for the type of precipitate corresponding to the current batch of precipitates under reference drying conditions in each drying section without nitrogen gas introduction;

[0034] determining the corresponding ideal gas impact energy range one at the initial reference precipitation humidity of each drying section, and determining the standard drying rate sequence one corresponding to the multiple gas impact energies in the ideal gas impact energy range one;

[0035] determining the corresponding ideal gas impact energy range two at the end reference precipitation humidity of each drying section, and determining the standard drying rate sequence two corresponding to the multiple gas impact energies in the ideal gas impact energy range two;

[0036] Step S73: obtaining the latest determined valve opening-gas impact energy fitting curve at the valve outlet of each drying section under the standard nitrogen source condition of each drying section;

[0037] Step S74: selecting the target valve opening of each drying section based on the fitting curve in step S73, the ideal gas impact energy range one, the ideal gas impact energy range two, the standard drying rate sequence one, and the standard drying rate sequence two of each drying section;

[0038] Step S75: controlling the current batch of precipitation to proceed with vacuum drying according to the target valve opening of each drying section determined in step S74.

[0039] Preferably, the ideal gas impact energy is the gas impact energy preventing the precipitation from agglomeration and splashing, and the gas impact energy is the product of the gas flow rate and the gas pressure; the reference drying condition of each drying section is the target range condition of each key parameter of the drying section, and step S74 includes:

[0040] Step S741: dividing each drying section into the initial reference precipitation humidity-critical humidity section and the critical humidity section-end reference precipitation humidity section;

[0041] Step S742: determining the required gas impact energy of the initial reference precipitation humidity-critical humidity section and the critical humidity section-end reference precipitation humidity section;

[0042] Step S743: determining the target valve opening of the initial reference precipitation humidity-critical humidity section and the critical humidity section-end reference precipitation humidity section according to step S73.

[0043] The technical solutions of the present application will be further described in detail below through the accompanying drawings and embodiments.

[0044] Compared with the prior art, the present application has the following beneficial effects:

[0045] Metal ions (such as Zn 2+ , Fe 2+) acts as a "chemical bridge," forming a coordinated bond with the carboxyl groups of fulvic acid and the amino groups of the polypeptide (rather than simply physically dispersing them). This allows the fulvic acid's root-promoting and soil-improving properties to synergize with the amino acid nutrition and enzyme-activating properties of the polypeptide. Field trials have shown that compared to physical mixing, it improves crop growth efficiency by 30%-50% (measured by wheat root fresh weight and chlorophyll content).

[0046] The bridging structure stabilizes the active functional groups of fulvic acid and polypeptides (e.g., fulvic acid carboxyl retention rate ≥90%, polypeptide secondary structure integrity rate ≥85%), preventing rapid microbial decomposition and inactivation by soil colloid adsorption. In soil, the loss rate of active ingredients is reduced by 25%-40%, and the fertilizer effect period is extended by 20-30 days.

[0047] The existing technology is prone to inactivation during processing and field environments due to the lack of chemical constraints. The method of the present invention solves the stability problem through multi-step reaction + parameter optimization:

[0048] Strictly control the reaction temperature (25-35°C) and pH (pH 5.0-6.0 for metal salt solutions and pH 6.5-7.5 for peptide reactions) to avoid peptide denaturation and reduce the risk of condensation of fulvic acid functional groups by 70%.

[0049] The three-dimensional network structure created by metal ion bridging makes the composite material more stable in soil acidity, alkalinity, and microbial environments. It improves soil compaction (e.g., aggregate content) by 40%, reduces soil fixation of trace elements (such as Zn and Fe) by 35% due to coordination protection, and increases crop absorption by 3-5 times.

[0050] While existing technologies lack the ability to coordinate nutrient release, the present method leverages the controlled dissociation of a bridging structure to achieve precise nutrient delivery. The metal ion-fulvic acid-polypeptide bridging structure responds to signals such as soil pH and root secretions, regulating the release rhythm of fulvic acid (for soil improvement and root growth), polypeptides (for amino acid replenishment and enzyme activation), and metal ions (for trace element supply). During the fruit tree's growth period, this method can meet the demands of the "budding" to "fruit expansion" to "color change" stages, increasing fertilizer utilization efficiency from 15% with physical mixing to over 40%.

[0051] Due to the synergistic activity and improved stability, the amount of fertilizer used can be reduced by 20%-30% with the same efficacy, while reducing soil salt accumulation (electrical conductivity decreases by 15%), helping green agriculture reduce production. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0053] Figure 1 Schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0054] The preferred embodiments of the present application will be described herein below with reference to the drawings, in which it is to be understood that the preferred embodiments described herein are illustrative of the application and are not intended to limit the present application. It is to be understood that the description and specific examples are intended for the purpose of illustration only and are not intended to limit the scope of the present application in any way.

[0055] In addition, the descriptions such as "first", "second", etc. in the present application are only for the purpose of description, and are not intended to particularly indicate the order or sequence, nor to limit the present application, which are merely for distinguishing components or operations described by the same technical terms, and cannot be understood as indicating or implying the relative importance of the technical features indicated or implying the number of technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In addition, the technical solutions and technical features of various embodiments can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor within the scope of protection required by the present application.

[0056] The present application provides the following embodiments:

[0057] The present application provides a preparation method of metal ion bridged fulvic acid-polypeptide ternary composite material, comprising:

[0058] Step S1: Preparation of fulvic acid solution: Add fulvic acid into a first solvent and stir to configure a fulvic acid solution; Preferably, the molecular weight of the fulvic acid is controlled within the range of 800-3000 Da (recommended 1000-5000 Da interval, this molecular weight segment has moderate functional group density, which is more conducive to metal ion bridging), and the carboxyl content is ≥3.5 mmol / g;

[0059] Step S2: Preparation of polypeptide solution: Dissolve polypeptide in a buffer solution and stir to configure a polypeptide solution;

[0060] Step S3: Preparation of metal ion solution: Add metal salt into a second solvent and stir to configure a metal salt solution, and the pH of the metal salt solution needs to be adjusted to 5.0-6.0 (inhibit hydrolysis and ensure effective ion concentration); If the metal salt contains easily oxidizable ions (such as Fe 2+ ), 0.01% of an antioxidant such as ascorbic acid can be supplemented to prevent oxidation of metal ions from affecting the reaction.

[0061] Step S4: Under stirring conditions, add the metal salt solution into the fulvic acid solution to react and form a composite solution; the stirring speed is 200-300 r / min, the reaction temperature is 25-35℃, the reaction time is 60-90 min, and the metal salt solution is added to the fulvic acid solution at a rate of 2-5 mL / min;

[0062] Step S5: under stirring, the polypeptide solution is added into the complex solution to obtain a mixture; the stirring speed is 150-200 r / min; the reaction pH is 6.5-7.5; the reaction time is 90-120 min;

[0063] Step S6: the mixture is subjected to centrifugal separation, and the precipitate is collected and washed; first, the precipitate is washed with deionized water for 3 times (to remove free small molecules; the amount of deionized water used is 3-5 times the volume of the precipitate), and then the precipitate is washed with anhydrous ethanol for 1 time (to remove organic impurities and reduce the surface energy; the volume of ethanol used is 2-3 times the volume of the precipitate);

[0064] Step S7: the washed precipitate is vacuum dried to obtain the metal ion bridged fulvic acid-polypeptide ternary composite material; the vacuum degree is -0.08 to -0.1 MPa, the drying temperature is 40-60°C, and the drying time is 2-4 hours;

[0065] Preferably, the first solvent is deionized water, and the fulvic acid is added into the first solvent at a mass / volume ratio of 1:20-1:30 (g:mL); the stirring time is 35-65 min (the stirring speed is 150-200 r / min).

[0066] Preferably, the polypeptide is a plant-derived polypeptide (such as soybean peptide, corn peptide, or wheat peptide) or an animal-derived polypeptide (fish peptide or collagen peptide), and the polypeptide is dissolved in a buffer solution at a mass / volume ratio of 1:80-1:150 (g:mL); the buffer solution is a phosphate buffer solution (or a Tris-HCl buffer solution); the concentration of the phosphate buffer solution is 0.05-0.1 mol / L, and the concentration of the Tris-HCl buffer solution is 0.05-0.2 mol / L.

[0067] Preferably, the second solvent is deionized water, and the concentration of the metal salt solution is 0.2-0.8 mol / L (preferably 0.3-0.6 mol / L; a too low concentration will result in insufficient bridging, and a too high concentration will easily cause precipitation).

[0068] Preferably, the polypeptide solution is added into the complex solution at a speed of 3-8 mL / min.

[0069] The above-mentioned scheme has the following beneficial effects:

[0070] The metal ions (such as Zn 2+ and Fe 2+ ) act as a "chemical bridge" and form coordinate bonds with the carboxyl groups of the fulvic acid and the amino groups of the polypeptide (rather than simple physical dispersion), so that the root-promoting and soil-improving functions of the fulvic acid and the amino acid nutrition and enzyme activation functions of the polypeptide are deeply synergized. Field tests show that, compared with physical mixing, the growth-promoting efficiency for crops is increased by 30%-50% (based on the fresh weight of wheat roots and the chlorophyll content).

[0071] The bridging structure stabilizes the active functional groups of fulvic acid and polypeptide (such as the retention rate of fulvic acid carboxyl is greater than or equal to 90%, and the integrity rate of polypeptide secondary structure is greater than or equal to 85%), avoids rapid decomposition by microorganisms and inactivation by soil colloids. In the soil, the loss rate of the active ingredients is reduced by 25%-40%, and the fertilizer efficiency period is prolonged by 20-30 days.

[0072] The prior art is prone to inactivation in processing and field environment due to the absence of chemical constraints. The method of the present application solves the stability problem through multi-step reaction + parameter optimization:

[0073] The reaction temperature (25-35℃) and pH (metal salt solution pH 5.0-6.0, polypeptide reaction pH 6.5-7.5) are strictly controlled to avoid polypeptide denaturation and reduce the risk of fulvic acid functional group condensation by 70%.

[0074] The three-dimensional network structure formed by metal ion bridging makes the composite material more stable in soil acid-base and microbial environment. The improvement effect on soil hardening (such as aggregate content) is increased by 40%, and the fixation rate of medium and trace elements (such as Zn, Fe) is reduced by 35% due to coordination protection, and the absorption rate of crops is increased by 3-5 times.

[0075] The prior art cannot control the release of nutrients synergistically, and the method of the present application realizes precise nutrient supply by means of controllable dissociation of the bridging structure: the bridging structure of metal ion-fulvic acid-polypeptide can respond to signals such as soil pH and root exudates to regulate the release rhythm of fulvic acid (soil improvement, root promotion), polypeptide (amino acid supplementation, enzyme activation), and metal ion (medium and trace element supply). In the growth period of fruit trees, it can match the needs of the stages of "germination-fruit expansion-color change", and the fertilizer utilization rate is increased from 15% of physical mixing to more than 40%.

[0076] Due to the synergy of activity and stability improvement, the fertilizer dosage can be reduced by 20%-30% under the same efficacy, and the soil salt accumulation (conductivity reduction of 15%) is also reduced, which helps green agriculture to reduce production.

[0077] The ternary composite material of the present application has the ability to stimulate plants and precisely supply medium and trace elements, and is environmentally friendly without residue in the soil. While solving specific problems, it also has environmental friendly characteristics, and has very broad application prospects.

[0078] In Example 2, on the basis of Example 1, the following steps are carried out before carrying out step S4 in batches:

[0079] Step S41: obtaining a reaction time-reaction liquid core parameter standard value fitting curve of each reaction liquid core parameter under the corresponding standard condition in the process of reacting the current kind of metal salt solution and the current kind of fulvic acid solution to form a composite solution, and dividing each fitting curve into a plurality of first segments according to the change rate of the corresponding parameter;

[0080] Step S42: Obtain several auxiliary standard curves, which are reaction time-reaction solution core parameter value fitting curves of each reaction solution core parameter under corresponding standard conditions during the reaction of the current metal salt solution and the current fulvic acid solution to form a composite solution; each auxiliary standard curve is marked with a corresponding standard comprehensive deviation coefficient of each core parameter (compared with the standard value fitting curve of step S41) and a standard comprehensive change state matching coefficient of each group of two associated core parameters (compared with the standard value fitting curve of step S41);

[0081] Step S43: performing a reaction test on the current batch of metal salt solution and the current batch of fulvic acid solution under corresponding standard conditions, repeatedly detecting actual core parameters of the reaction solution during the reaction test, and constructing a reaction time-reaction solution core parameter value fitting curve for each reaction solution core parameter; dividing the reaction time-reaction solution core parameter value fitting curve for each reaction solution core parameter into second segments corresponding one-to-one to the corresponding first segments;

[0082] Step S44: determining the actual deviation coefficient of each core parameter corresponding to each second segment and the change state matching coefficient of the two associated core parameters (whether the parameter change trends are synchronized) based on the first segment and the second segment;

[0083] Step S45: Based on step S44, a target auxiliary standard curve is selected from the auxiliary standard curves obtained in step S42;

[0084] Step S46: Determine the target dropping speed for the current batch of metal salt solution and the current batch of fulvic acid solution in step S4 based on the target auxiliary standard curve (take the dropping speed of any target auxiliary standard curve, or the average of the dropping speeds of multiple target auxiliary standard curves).

[0085] Preferably, the core parameters include: conductivity, ultraviolet absorbance;

[0086] The difference between the maximum conductivity change rate and the minimum conductivity change rate in each first segment of the reaction time-reaction solution conductivity standard value fitting curve corresponding to conductivity is less than the corresponding preset difference; for example, in the early stage, metal ions are rapidly complexed and the conductivity drops rapidly; in the later stage, the reaction is slow and the conductivity drops slowly;

[0087] The corresponding standard conditions are: the median of the corresponding standard stirring speed range (a reasonable range of stirring speeds determined in preliminary experiments or industry standards, in which the stirring and reaction effects meet the requirements) and the median of the standard addition rate range of the metal salt solution (a reasonable range of metal salt droplet addition speeds determined in preliminary experiments or industry standards, in which the reaction effects meet the requirements);

[0088] The corresponding reaction times of the first segment and the second segment are the same.

[0089] Step S45 includes:

[0090] Step S451: determining the actual comprehensive deviation coefficient of each core parameter and the actual comprehensive change state matching coefficient of each group of associated two core parameters based on the actual deviation coefficient of each core parameter corresponding to the second segment and the change state matching coefficient of the associated two core parameters;

[0091] Step S452: Determine the target auxiliary standard curve based on step S451; the target auxiliary standard curve meets the following conditions: j '+W j |≤W j00 ; and |K s '-1|≤K s00 , and |K s '-K s |≤K s01 W j ' is the standard comprehensive deviation coefficient of the jth core parameter of the target auxiliary standard curve (obtained based on the calculation method of the actual comprehensive deviation coefficient of the following formula); W j00 W j '+W j The corresponding maximum allowable residual deviation threshold (the value can be greater than or equal to 0.03 and less than 0.15); K j K is the standard comprehensive change state matching coefficient of the two core parameters associated with the sth group of the target auxiliary standard curve; s00 K s '-1|corresponding deviation threshold (the value can be greater than or equal to 0.05 and less than 0.15); K s01 The deviation threshold of the allowable comprehensive change state matching coefficient between the current batch and the auxiliary curve (the value can be greater than or equal to 0.05 and less than 0.13); the above deviation threshold is determined by "quality requirement reverse deduction + production fluctuation adaptation + long-term data verification";

[0092] in,

[0093]

[0094] Among them, W ij is the actual deviation coefficient of the second segment of the i-th core parameter; E ij is the average parameter value of the second segment of the jth core parameter; E ij0 is the average parameter value of the first segment of the jth core parameter; W j is the actual comprehensive deviation coefficient of the jth core parameter; L jis the total reaction time of all first segments of the jth core parameter; L ji is the total reaction time of the first segment of the i-th core parameter; M j The total number of first segments divided for the jth core parameter;

[0095] K is0 is the change state matching coefficient of the second segment of the i-th target of the two core parameters associated with the s-th group (such as conductivity and ultraviolet absorbance) (in the two groups of associated core parameters, the first segment of the core parameter with the largest number of first segments is the target first segment (such as the first segment corresponding to conductivity), and the second curve of the parameter corresponding to the target first segment is the target second segment); F is1 is the average parameter change rate of the second segment of the i-th target of the two core parameters associated with the s-th group; F is2 The core parameter of the non-target second segment of the two core parameters associated with the sth group is in F is1 The average parameter change rate corresponding to the corresponding reaction time period; F hs0 for The corresponding ideal value (the first segment of the h-th target and corresponding value); K s is the actual comprehensive change state matching coefficient of the two core parameters associated with the sth group; R s The total reaction time of the first segment of all targets in the two core parameters associated with group s; R sh N is the total reaction time of the first segment of the hth target in the two core parameters associated with the sth group; s The total number of target first segments divided by the two core parameters associated with the sth group.

[0096] Objective: To resolve product quality fluctuations caused by differences in reaction characteristics of different batches of raw materials, and ensure that each batch of reactions follows the "optimal path" by "building a model using the standard curve → measuring deviations from actual reactions → adjusting parameters using the auxiliary curve."

[0097] The beneficial effects of the above scheme are:

[0098] By segmenting the reaction according to the rate of change of core parameters and adapting to the kinetic characteristics of different stages (such as the rapid-change stage of rapid metal ion complexation and the stable stage of slow reaction), segmented, differentiated, and precise control is achieved. Compared with traditional "one-size-fits-all" parameter control, the fluctuation range of core parameters (such as conductivity and absorbance) in each reaction stage can be compressed from ±10% to ±3%, avoiding local over-reactions caused by misjudgment of stage characteristics (such as product agglomeration caused by over-complexation), and ensuring product quality consistency from the source of the reaction process.

[0099] To address batch differences in raw materials (such as fluctuations in metal salt concentration and fulvic acid activity), the system automatically matches the target auxiliary standard curve and adjusts parameters based on the auxiliary standard curve library. When raw material fluctuations reach ±15%-20%, the effects of these differences can still be offset through curve matching, keeping cross-batch core parameter deviations within 3%-5%, and increasing product quality consistency from 70% to over 95%. At the same time, the experience of process personnel is converted into digital curves and algorithms, significantly reducing human training costs and the risk of relying on experience.

[0100] The reaction process does not require human intervention. It relies on algorithms to automatically screen auxiliary curves and dynamically adjust parameters. With the help of auxiliary curves, parameters are pre-optimized, and the initial condition trial and error phase is skipped. The reaction cycle can be shortened by 20%-30%, and production capacity increased by 25%, achieving cost-cutting and efficiency-enhancing production rhythm optimization.

[0101] Example 4, based on any one of Examples 1-3, the washed precipitate is spread on a tray and dried in a vacuum drying chamber, and a nitrogen gas flow containing CO2 is sprayed toward the porous holes of the tray, and a nitrogen gas inlet pipe is provided in the vacuum drying chamber, and a valve is provided in the nitrogen gas inlet pipe;

[0102] Step S7 includes:

[0103] Step S71: Obtaining the target range of each key parameter of the corresponding type of precipitation in each drying section of the current batch of precipitation and the standard concentration of CO2 in the CO2-containing nitrogen gas flow, wherein the key parameters include: room temperature in the drying chamber and vacuum degree in the drying chamber;

[0104] Step S72: determining a fitting curve of drying time-reference precipitate humidity in each drying section for the type of precipitate corresponding to the current batch of precipitates under reference drying conditions in each drying section without nitrogen gas introduction;

[0105] and determining an ideal gas impulse energy range 1 corresponding to the initial reference precipitation humidity of each drying section, and determining a standard drying rate sequence 1 corresponding to a plurality of gas impulse energies within the ideal gas impulse energy range 1;

[0106] and determining a second ideal gas impulse energy range corresponding to the reference precipitation humidity at the end of each drying section, and determining a second standard drying rate sequence corresponding to a plurality of gas impulse energies within the second ideal gas impulse energy range;

[0107] Step S73: obtaining the latest determined fitting curve of the valve opening of each drying section and the gas impulse energy at the valve outlet under the standard nitrogen source condition of each drying section;

[0108] Step S74: Based on the fitting curve in step S73 for each drying section, the ideal gas impulse energy range 1, the ideal gas impulse energy range 2, the standard drying rate sequence 1, and the standard drying rate sequence 2, select a target valve opening for each drying section;

[0109] Step S75: according to the target valve opening degree of each drying section determined in step S74, the current batch of precipitates is subjected to vacuum drying.

[0110] Preferably, the ideal gas impact energy is the gas impact energy that prevents the agglomeration of the precipitates and the splashing of the precipitates, and the gas impact energy is the product of the gas flow rate and the gas pressure; the reference drying condition of each drying section is the target range condition of each key parameter of the drying section, and step S74 comprises:

[0111] Step S741: dividing each drying section into an initial reference precipitate humidity-critical humidity section and a critical humidity section-end reference precipitate humidity section;

[0112] Step S742: determining the required gas impact energy of the initial reference precipitate humidity-critical humidity section and the critical humidity section-end reference precipitate humidity section;

[0113] Step S743: determining the target valve opening degree of the initial reference precipitate humidity-critical humidity section and the critical humidity section-end reference precipitate humidity section according to step S73.

[0114] 1. The same kind of precipitates meet: meet the consistency of ingredients, the consistency of surface properties, and the consistency of particle size distribution;

[0115] Consistency of ingredients: the content deviation of main ingredients (such as fulvic acid, polypeptide) is ≤5% (determined by elemental analysis and titration method), and the infrared spectrum peak intensity deviation of characteristic functional groups (such as -COOH, -NH2) is ≤10%;

[0116] Consistency of surface properties: zeta potential deviation is ≤15 mV (reflecting the uniformity of surface charge), and water contact angle deviation is ≤10° (reflecting the uniformity of hydrophilic and hydrophobic properties);

[0117] Consistency of particle size distribution: the deviation of median particle size (D50) is ≤10%, and the overlapping degree of particle size distribution range (D10-D90) is ≥80% (determined by a laser particle size analyzer)

[0118] 2. Key parameter (drying chamber temperature, vacuum degree) target range

[0119] Determined by pre-experiment:

[0120] Take 3 batches of the same kind of precipitates, set different chamber temperatures (such as 40℃ / 50℃ / 60℃) and vacuum degrees (such as -0.06MPa / -0.08MPa / -0.1MPa) in the vacuum drying chamber, and test the agglomeration rate (sieving method: passing through a 200-mesh sieve, weighing the proportion of agglomerates on the sieve) and the activity retention rate (such as the carboxyl retention rate of fulvic acid, determined by titration method) of the precipitates after drying.

[0121] The room temperature and vacuum range of "agglomeration rate ≤ 5% and activity retention rate ≥ 90%" was selected as the target range.

[0122] 3. Standard CO2 concentration in nitrogen containing CO2

[0123] Based on the needs of anti-oxidation and promoting dispersion:

[0124] The role of CO2 is to inhibit the metal ions (such as Fe 2+ ) oxidation (avoiding the formation of insoluble oxides that lead to agglomeration), while trace amounts of CO2 can reduce the interfacial tension between nitrogen and the precipitation surface (reducing particle adsorption and agglomeration).

[0125] A concentration gradient (0.5% / 1% / 2% / 5% CO2, the remainder being nitrogen) was tested, and the changes in the valence state of metal ions were detected by X-ray photoelectron spectroscopy (XPS). The dispersion was observed under a microscope, and the concentration with "no oxidation and the best dispersion" was selected as the standard concentration (usually 1% to 3%).

[0126] 4. Step S72: Obtaining the reference curve and ideal gas impulse energy range

[0127] Drying time-base precipitation humidity fitting curve

[0128] Operation: Under the reference drying conditions (i.e., the room temperature and the median of the vacuum target range determined by S71), without nitrogen, take samples every 10 minutes to measure the precipitation humidity (infrared moisture meter), record the "time-humidity" data, and use the least squares method to fit the curve.

[0129] Ideal gas energy range 1 / 2 (anti-agglomeration + non-splashing)

[0130] Definition: Gas impulse energy = flow rate × air pressure (unit: L·kPa / s, calculated in real time by flow meter and pressure gauge).

[0131] Test method (taking initial benchmark precipitation humidity as an example):

[0132] Fix the room temperature and vacuum degree as the reference value, introduce nitrogen containing CO2 into the precipitate, and adjust the flow rate and pressure to change the impact energy;

[0133] Standard drying rate sequence one / two

[0134] Within the ideal impulse energy range, five gradient impulse energies were selected to test the humidity drop per unit time (drying rate = Δhumidity / Δtime) to form a rate sequence (corresponding to the rate value of each impulse energy).

[0135] 5. Step S73: Obtaining the valve opening-gas impulse energy fitting curve

[0136] Under a standard nitrogen source (pressure stable at 0.3MPa, CO2 concentration at standard concentration), adjust the valve opening from 10% to 100% in a 10% gradient. After each opening is stable for 3 minutes, use an online flow meter (to measure flow rate) and a pressure gauge (to measure valve outlet pressure) to calculate the impact energy (impact energy = flow rate × pressure).

[0137] Fitting curve:

[0138] With "valve opening" as the x-axis and "corresponding impulse energy" as the y-axis, polynomial fitting is used to obtain the value of the valve opening through R 2 Test (R 2 ≥0.95 is qualified) to ensure the accuracy of the curve.

[0139] Step S74: Obtaining the target valve opening

[0140] Step S741: Divide critical humidity segments

[0141] The critical humidity is the "energy demand mutation point": from the "drying time-reference precipitation humidity fitting curve" of step S72, find the point where the humidity drop rate begins to slow down (such as the inflection point from rapid dehydration to slow shaping, the precipitation humidity value from the "rapid decline stage" to the "slow decline stage"), and use this as the boundary to divide the two sub-segments.

[0142] Step S742: Determine the energy demand of each sub-segment

[0143] Initial baseline precipitation humidity - critical humidity range: prioritize matching the ideal gas impulse energy range 1, and select the impulse energy with "rate ≥ target value (set different rates, measure quality (crystals, functional groups, agglomeration), and find the rate range where "quality meets the requirements", such as 0.5% humidity / minute)" from the standard rate sequence 1 as the required gas impulse energy;

[0144] Critical humidity section - the final reference precipitation humidity section: Similarly, the required gas impulse energy is selected from the ideal gas impulse energy range 2 and rate sequence 2.

[0145] Step S743: Reverse-calculate the target valve opening

[0146] According to the fitting curve in step S73, the required gas impulse energy is substituted to obtain the corresponding target valve opening.

[0147] The beneficial effects of the above scheme are:

[0148] 1. Breaking through the traditional "single drying parameter" control mode, the drying process is divided into the "free water removal section" and the "bound water removal section" through critical humidity identification (the inflection point of sudden change in drying rate), accurately matching the gas impulse energy requirements in different humidity ranges (high impulse energy is required to prevent agglomeration in the high humidity section, and low impulse energy is required to prevent splashing in the low humidity section), solving the industry problem of "dynamic changes in energy demand during the drying process but static control".

[0149] A four-dimensional correlation model of "precipitation humidity - drying time - gas impulse energy - valve opening" was constructed and quantified through small-scale experiments:

[0150] Nonlinear relationship between humidity and drying rate (exponential decay model);

[0151] Fitting curve of valve opening and gas impulse energy (quadratic polynomial correlation);

[0152] Realize the leap from "empirical control" to "data-driven control" and provide a universal modeling method for drying complex systems.

[0153] 2. Quality Improvement: Ensuring the Structural Integrity and Functional Stability of the Bridge

[0154] Agglomeration control: By limiting the gas energy range (such as matching the initial energy to the anti-agglomeration threshold) and combining the "interfacial tension reduction" effect of CO2 and nitrogen, the dispersion of precipitated particles is increased by 30%-50% (verified by screening method), avoiding "functional group encapsulation" or "metal ion dislocation" of the bridging structure due to agglomeration.

[0155] Oxidation inhibition: Precisely control the concentration of CO2-containing nitrogen (1%-3%) to inhibit the oxidation of easily oxidized metal ions (such as Fe 2+ ) is reduced to ≤5% (XPS detection), ensuring the chemical stability of the bridging site.

[0156] The segmented drying control increases the carboxyl retention rate of fulvic acid to ≥90% (titration method) and the amino loss rate of polypeptides to ≤3% (infrared spectrum), avoiding the problem of "high temperature / strong impact causing molecular chain breakage" in traditional drying and ensuring the biological activity and chelation function of the composite material.

[0157] Through "critical humidity segmentation + dynamic energy matching", the drying time is shortened by 20%-30% compared with the traditional "constant parameter drying":

[0158] The free water removal section (high impulse energy) accelerates water evaporation, increasing the rate by 15%-25%;

[0159] Precise control of the combined water removal section (low impact energy) avoids rework and reduces ineffective drying time.

[0160] Rapidly migrate process parameters by reusing quantitative criteria (composition, particle size, surface properties) for the same type of precipitation.

[0161] 4. Cost Control: Reduce Energy Consumption and Defective Rate

[0162] The coordinated control of vacuum degree and impulse energy reduces energy consumption in the drying process by 15%-20% (power monitoring):

[0163] The high-humidity section uses high vacuum to accelerate dehydration (reducing heating energy consumption), and the low-humidity section reduces vacuum and impulse energy (reducing gas power energy consumption);

[0164] The recycling (recovery and separation) of CO2 and nitrogen can reduce gas costs by 25%-35%.

[0165] Precise control makes the sedimentation agglomeration defect rate ≤5% (screening method) and the activity loss defect rate ≤3% (activity detection), which is significantly lower than the "defective rate of 10%-20%" of traditional drying, reducing raw material waste and rework costs.

[0166] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a metal ion-bridged fulvic acid-polypeptide ternary composite material, characterized by: include: Step S1: preparing a fulvic acid solution: adding fulvic acid to a first solvent and stirring to prepare a fulvic acid solution; Step S2: Preparation of polypeptide solution: dissolving the polypeptide in a buffer solution and stirring to prepare a polypeptide solution; Step S3: preparing a metal ion solution: adding a metal salt to a second solvent and stirring to prepare a metal salt solution; Step S4: adding the metal salt solution to the fulvic acid solution under stirring to react and form a composite solution; Step S5: adding the polypeptide solution to the composite solution under stirring to obtain a mixed solution; Step S6: centrifuging the mixed solution, collecting the precipitate, and washing the precipitate; Step S7: The washed precipitate is vacuum dried to obtain a metal ion-bridged fulvic acid-polypeptide ternary composite material.

2. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 1, characterized in that: The first solvent is deionized water, and fulvic acid is added to the first solvent at a mass volume ratio of 1:20 to 1:30 (g:mL).

3. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 1, characterized in that: The polypeptide is a plant-derived polypeptide or an animal-derived polypeptide, and is dissolved in a buffer solution at a mass-to-volume ratio of 1:80 to 1:150 (g:mL), wherein the buffer solution is a phosphate buffer solution.

4. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 1, characterized in that: The second solvent is deionized water, and the concentration of the metal salt solution is 0.2-0.8 mol / L.

5. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 1, characterized in that: The polypeptide solution is added dropwise to the composite solution at a speed of 3 to 8 mL / min.

6. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 1, characterized in that: Before performing step S4 in batches, perform the following steps: step S41: obtaining a reaction time-standard value fitting curve of each core parameter of the reaction solution under corresponding standard conditions during the process of forming a composite solution by reacting the current metal salt solution and the current fulvic acid solution, and dividing each fitting curve into a plurality of first segments according to the change rate of the corresponding parameter; Step S42: obtaining a plurality of auxiliary standard curves, wherein the auxiliary standard curves are fitting curves of reaction time and core parameter value of each core parameter of the reaction solution under corresponding standard conditions during the process of the reaction between the current metal salt solution and the current fulvic acid solution to form a composite solution; Step S43: performing a reaction test on the current batch of metal salt solution and the current batch of fulvic acid solution under corresponding standard conditions, repeatedly detecting the actual core parameters of the reaction solution during the reaction test, and constructing a reaction time-core parameter value fitting curve for each core parameter of the reaction solution; Dividing the reaction time-reaction solution core parameter value fitting curve of each reaction solution core parameter into second segments corresponding to the corresponding first segments one by one; Step S44: determining the actual deviation coefficient of each core parameter corresponding to each second segment and the change state matching coefficient of the two associated core parameters based on the first segment and the second segment; Step S45: Based on step S44, a target auxiliary standard curve is selected from the auxiliary standard curves obtained in step S42; Step S46: Determine the target drop rate for the current batch of metal salt solution and the current batch of fulvic acid solution in step S4 based on the target auxiliary standard curve.

7. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 6, characterized in that: The core parameters include: conductivity, ultraviolet absorbance; The difference between the maximum conductivity change rate and the minimum conductivity change rate in each first segment of the reaction time-reaction liquid conductivity standard value fitting curve corresponding to the conductivity is less than the corresponding preset difference; The corresponding standard conditions are: the median of the corresponding standard stirring speed range and the median of the standard addition speed range of the metal salt solution; The corresponding reaction times of the first segment and the second segment are the same.

8. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 1, characterized in that: The washed precipitate is spread flat on a tray and dried in a vacuum drying chamber, and a nitrogen gas flow containing CO2 is sprayed toward the porous surface of the tray. A nitrogen gas inlet pipe is provided in the vacuum drying chamber, and a valve is provided in the nitrogen gas inlet pipe. Step S7 includes: Step S71: Obtain the target range of each key parameter of the corresponding type of precipitation in each drying section of the current batch of precipitation and the standard concentration of CO2 in the CO2-containing nitrogen gas flow, the key parameters including: room temperature in the drying chamber and vacuum degree in the drying chamber; Step S72: determining a fitting curve of drying time-reference precipitate humidity in each drying section for the type of precipitate corresponding to the current batch of precipitates under reference drying conditions in each drying section without nitrogen gas introduction; and determining an ideal gas impulse energy range 1 corresponding to the initial reference precipitation humidity of each drying section, and determining a standard drying rate sequence 1 corresponding to a plurality of gas impulse energies within the ideal gas impulse energy range 1; and determining a second ideal gas impulse energy range corresponding to the reference precipitation humidity at the end of each drying section, and determining a second standard drying rate sequence corresponding to a plurality of gas impulse energies within the second ideal gas impulse energy range; Step S73: obtaining the latest determined fitting curve of the valve opening of each drying section and the gas impulse energy at the valve outlet under the standard nitrogen source condition of each drying section; Step S74: Based on the fitting curve in step S73 for each drying section, the ideal gas impulse energy range 1, the ideal gas impulse energy range 2, the standard drying rate sequence 1, and the standard drying rate sequence 2, select a target valve opening for each drying section; Step S75: Control the current batch of precipitates to perform vacuum drying according to the target valve opening of each drying section determined in step S74.

9. The method for preparing the metal ion-bridged fulvic acid-polypeptide ternary composite material according to claim 8, characterized in that: The ideal gas impact energy is the gas impact energy that prevents sediment agglomeration and does not splash the sediment. The gas impact energy is the product of gas flow rate and gas pressure. The baseline drying condition of each drying section is the target range condition of each key parameter of the drying section. Step S74 includes: Step S741: Divide each drying section into an initial reference precipitation humidity-critical humidity section and a critical humidity section-final reference precipitation humidity section; Step S742: determining the required gas impulse energy for the initial reference precipitation humidity-critical humidity segment and the required gas impulse energy for the critical humidity segment-final reference precipitation humidity segment; Step S743: Determine the target valve openings of the initial reference precipitation humidity-critical humidity section and the critical humidity section-final reference precipitation humidity section according to step S73.

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