Method for preparing fertilizer based on ultrafiltration pretreatment of glutamic acid fermentation liquor

Abstract

The invention discloses a method for preparing a fertilizer based on ultrafiltration pretreatment of glutamic acid fermentation liquor, and relates to the technical field of fertilizer preparation, and the method has the advantages that by preparing a composite adsorption material G of which the core is nano silicon dioxide particles, firstly, the nano silicon dioxide particles are pretreated, so that the surfaces of the nano silicon dioxide particles are connected with amino functional groups; the preparation method comprises the following steps: preparing a nano silicon dioxide MOF composite material, synthesizing the nano silicon dioxide MOF composite material with a nitrogen-containing organic ligand (2-aminoterephthalic acid) and a metal ion source (zinc ion salt) through a solvothermal method, and finally, carrying out surface modification by using an aldehyde group functionalized silane coupling agent, so that the surface of the material has aldehyde groups, and the composite adsorption material G can adsorb glutamic acid. The method has the advantages that the method is simple to operate, interference of other impurities in fermentation liquor on glutamic acid is eliminated, the extraction purity of glutamic acid is remarkably improved, the effective content of glutamic acid in the fertilizer is higher in the fertilizer preparation process, higher-quality and more accurate nutrients can be provided for crops, and growth and development of the crops are better promoted.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, in particular to a method for preparing fertilizer based on ultrafiltration pretreatment of glutamic acid fermentation liquid. Background Art

[0002] Glutamic acid is an important amino acid, which is widely used in food, medicine, cosmetics and other fields. The production of glutamate is mainly carried out by fermentation. A large amount of fermentation liquid is produced during the fermentation process of glutamate. These fermentation liquids contain rich nutrients, such as amino acids, organic acids, sugars, vitamins, etc. If they can be effectively utilized and prepared into fertilizers, it can not only achieve resource recycling, but also reduce environmental pollution.

[0003] The prior art has certain technical defects. First, when processing glutamate fermentation broth, the prior art lacks effective means to accurately adsorb glutamate, resulting in greater interference of impurities in the fermentation broth on glutamate, resulting in low purity of glutamate extraction. Secondly, the catalyst in the prior art cannot accurately act on glutamate and related specific components, and is prone to adverse reactions with other amino acids during the catalytic process, affecting the quality of the fertilizer. Furthermore, the prior art cannot achieve accurate regulation of glutamate content in fertilizer preparation, and often leads to nutrient waste or deficiency due to unreasonable glutamate content, thereby reducing the utilization rate of the fertilizer. To this end, we propose a method for preparing fertilizer based on ultrafiltration pretreatment of glutamate fermentation broth. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing fertilizer by ultrafiltration pretreatment of glutamate fermentation broth.

[0005] In order to solve the problems raised in the above background technology, the present invention provides the following technical solution: a method for preparing fertilizer based on ultrafiltration pretreatment of glutamic acid fermentation broth, the method for preparing fertilizer specifically comprising the following steps:

[0006] Step 1: Perform preliminary testing on the glutamic acid fermentation broth, and perform ultrafiltration treatment on the fermentation broth through an ultrafiltration membrane to remove bacteria, protein and pigment impurities in the fermentation broth to improve the purity of the fermentation broth;

[0007] Step 2, preparing a composite adsorption material G, preparing nano-silica particles with a particle size of 20nm-50nm, selecting 2-aminoterephthalic acid as a nitrogen-containing organic ligand, selecting a zinc ion salt as a metal ion source, and selecting an aldehyde-functionalized silane coupling agent as an organic silane coupling agent, synthesizing a nano-silica MOF composite material by a solvent thermal method, and then performing surface modification with an aldehyde-functionalized silane coupling agent to obtain a composite adsorption material G, wherein the composite adsorption material G selectively and efficiently adsorbs glutamate through a Schiff base reaction between the surface aldehyde group and the amino group of glutamic acid;

[0008] Step 3, preparing a new catalyst, the new catalyst is composed of a transition metal oxide cobalt trioxide and a nitrate of a rare earth element lanthanum, weighing cobalt nitrate and lanthanum nitrate, respectively, dissolving them in deionized water, then stirring and dissolving, then mixing the two solutions together, and slowly dropping a precipitant sodium hydroxide solution to precipitate metal ions, filtering, washing and drying to obtain a catalyst precursor, then calcining the catalyst precursor to obtain a new catalyst with a specific structure and performance, then adding the catalyst to the fermentation broth to accelerate the chemical reaction between glutamate and the fermentation broth, generating an intermediate product that is beneficial to the preparation of fertilizers, and improving the nutrient content and stability of the fertilizers;

[0009] Step 4: introducing pressure-responsive polymer gel to treat the fermentation broth. First, raw materials for synthesizing pressure-responsive polymer gel are prepared, including hydroxyethyl methacrylate, ethylene glycol dimethacrylate and initiator azobisisobutyronitrile. Hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed and added to a reaction container filled with an organic solvent toluene, and stirred and mixed under a nitrogen environment. The initiator azobisisobutyronitrile is slowly added to the reaction system for reaction, and the pressure-responsive polymer gel is synthesized by free radical polymerization. In the ultrafiltration pretreatment stage, the synthesized polymer gel is placed in a treatment device, and the volume of the polymer gel is shrunk by applying pressure to the fermentation broth, glutamic acid is selectively adsorbed, and the ultrafiltration efficiency is improved. In the fertilizer preparation stage, the pressure is reduced to expand the volume of the polymer gel, release glutamic acid, and achieve precise regulation of glutamic acid.

[0010] Step 5: prepare the fertilizer formula to ensure that the ratio of nitrogen, phosphorus and potassium macroelements is N:P:K=3:2:3, and trace elements such as iron, zinc and copper are added at the same time, and the ratio of trace elements is iron:zinc:copper=1:0.5:0.3. Then, the ultrafiltered fermentation liquid is mixed with the fertilizer raw material. During the mixing process, the stirring speed is controlled at 50r / min to 100r / min. Subsequently, the fertilizer is subjected to deodorization technology, the prepared fertilizer is subjected to special treatment, and finally the fertilizer is packaged in sealed plastic bags.

[0011] As a further solution of the present invention: in the step 1, the pore size of the ultrafiltration membrane is 0.01 μm-0.1 μm, its material is polyethersulfone, and the set pressure is 0.2 MPa-0.5 MPa.

[0012] As a further scheme of the present invention: in the step 2, in the synthesis of the composite adsorbent material G, the surface of the nano-silica particles is pretreated with a silane coupling agent. In the pretreatment process, the nano-silica particles are first dispersed in an ethanol solution, and the silane coupling agent is added, and the reaction is stirred at 40°C-50°C for 3h-5h. After the reaction is completed, it is filtered, washed and dried at 80°C-100°C for 2h-3h, so that the surface of the nano-silica particles is connected with amino functional groups, so that it can be combined with nitrogen-containing organic ligands and metal ion sources in the solvent thermal reaction. The grafting rate of the aldehyde-functionalized silane coupling agent is 80%-90%, ensuring that the adsorption selectivity and adsorption capacity of glutamic acid per gram of adsorbent material reach 50㎎-80㎎ of glutamic acid.

[0013] As a further scheme of the present invention: in the step three, during the preparation of the catalyst, the weighing amount of cobalt nitrate is 10g-20g, the weighing amount of lanthanum nitrate is 5g-10g, the amount of dissolved deionized water is 100ml-200ml respectively, the stirring temperature is 30℃-40℃, the stirring speed is 100r / min-150r / min, the dripping speed of the precipitant sodium hydroxide solution is 5ml-10ml per minute, the reaction temperature is 80℃-100℃, the reaction time is 6h-10h, the drying temperature is 80℃-100℃, the drying time is 4h-6h, the catalyst precursor calcination temperature is 400℃-600℃, and the calcination time is 4h-8h.

[0014] As a further scheme of the present invention: in the step 4, the amount of hydroxyethyl methacrylate is 15g-25g, the amount of ethylene glycol dimethacrylate is 5g-15g, the amount of initiator azobisisobutyronitrile is 0.5g-1.5g, the amount of organic solvent toluene is 150ml-250ml, the stirring temperature is 30°C-40°C, the stirring time is 30min-60min, after adding the initiator, the reaction temperature is controlled to be 60°C-80°C, the reaction time is 8h-12h, the pressure applied to the fermentation liquid in the ultrafiltration pretreatment stage is 0.8MPa-1.2MPa, and the pressure in the fertilizer preparation stage is 0.1MPa-0.3MPa.

[0015] As a further solution of the present invention: In the step five, the deodorization technology adopts a method of activated carbon adsorption combined with biological deodorant spraying, the adsorption capacity of activated carbon is 50ml-80ml of odorous gas per gram of activated carbon, and the spraying amount of biological deodorant is 100ml-150ml per cubic meter of space, ensuring that the deodorization effect reaches more than 90% of the odorous gas removal rate.

[0016] As a further solution of the present invention: in the step 2, the nano-silicon dioxide MOF composite material is synthesized by a solvothermal method, the synthesis temperature is 150° C.-200° C., and the synthesis time is 12 h-24 h.

[0017] As a further solution of the present invention: in the step 5, when the ultrafiltered fermentation liquid is mixed with other fertilizer raw materials, the other fertilizer raw materials are first preheated at a temperature of 40°C-60°C for 20min-40min, and then during the stirring and mixing process, an intermittent stirring method is adopted, with a pause of 1min-2min every 5min-8min of stirring.

[0018] As a further scheme of the present invention: in the step 5, when the prepared fertilizer is subjected to special treatment, in addition to spraying a moisture-proof agent on the surface of the fertilizer, a vacuum drying treatment is also adopted, the fertilizer is placed in a vacuum drying device, the vacuum degree is controlled at -0.08MPa to -0.1MPa, the drying temperature is 50°C-70°C, the drying time is 3h-5h, and the water content of the fertilizer is ensured to be less than 5%, thereby further improving the stability of the fertilizer and preventing moisture absorption, caking and decomposition.

[0019] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The present invention prepares a composite adsorption material G, the core of which is nano-silica particles. First, the nano-silica particles are pretreated to attach amino functional groups to their surfaces. Then, the nano-silica MOF composite material is synthesized by a solvent thermal method with a nitrogen-containing organic ligand (2-aminoterephthalic acid) and a metal ion source (zinc ion salt). Finally, an aldehyde-functionalized silane coupling agent is used for surface modification to make the material surface have aldehyde groups. The aldehyde groups can react with the amino groups of glutamic acid to produce a Schiff base reaction. The reaction equation is R-CHO (aldehyde groups on the material surface) + H 2N-CH(COOH)-(CH2)2-COOH(glutamic acid)→R-CH=N-CH(COOH)-(CH2)2-COOH(adsorption product)+H2O. Through this specific reaction, the composite adsorption material G can accurately adsorb glutamic acid, effectively eliminate the interference of other impurities in the fermentation broth on glutamic acid, and significantly improve the extraction purity of glutamic acid. In the fertilizer preparation process, this makes the effective content of glutamic acid in the fertilizer higher, which can provide crops with better quality and more precise nutrients, thereby better promoting the growth and development of crops.

[0021] 2. The present invention prepares a novel catalyst, which is composed of a specific transition metal oxide (cobalt trioxide) and a rare earth element (lanthanum nitrate). The structure and performance of the catalyst are precisely controlled by a coprecipitation method. The catalyst can accelerate the chemical reaction between glutamic acid and specific components in the fermentation broth, and can promote the esterification reaction between the carboxyl group of glutamic acid and the hydroxyl group of certain organic matter in the fermentation broth, thereby improving the nutrient content and stability of the fertilizer. The catalyst has high selectivity and high efficiency under mild conditions, can accurately act on glutamic acid and related specific components, and avoid adverse reactions with other amino acids. In agricultural applications, the fertilizer prepared using the novel catalyst can better meet the nutritional needs of crop growth, improve the yield and stress resistance of crops, and ensure the good growth of crops under complex environmental conditions.

[0022] 3. The present invention applies pressure to the fermentation liquid in the ultrafiltration pretreatment stage, so that the gel will shrink in volume and its internal structure will change, so that the gel can selectively adsorb glutamate. This adsorption is based on the specific interaction between the molecular structure of the gel and glutamate. In the fertilizer preparation stage, the pressure is reduced, the gel volume expands, and glutamate is released. Through this pressure response mechanism, precise regulation of glutamate is achieved. The unique performance of this gel not only optimizes the fermentation liquid treatment process, but also can flexibly adjust the glutamate content in the fertilizer according to the demand for glutamate of different crops, thereby avoiding nutrient waste or deficiency caused by unreasonable glutamate content and improving the utilization rate of the fertilizer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the method steps in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram comparing the performance of composite adsorption materials in the embodiments of the present invention;

[0025] Figure 3 This is a schematic diagram of the performance data comparison of the catalysts in the embodiments of the present invention;

[0026] Figure 4 This is a schematic diagram of crop growth index data comparison in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0028] In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] Please see attached Figure 1 -Attached Figure 4 The present invention provides a method for preparing fertilizer based on ultrafiltration pretreatment of glutamic acid fermentation broth, and the method for preparing fertilizer specifically comprises the following steps:

[0030] Step 1: Perform preliminary testing on the glutamic acid fermentation broth, and perform ultrafiltration treatment on the fermentation broth through an ultrafiltration membrane to remove bacteria, protein and pigment impurities in the fermentation broth to improve the purity of the fermentation broth;

[0031] Step 2, preparing a composite adsorption material G, preparing nano-silica particles with a particle size of 20nm-50nm, selecting 2-aminoterephthalic acid as a nitrogen-containing organic ligand, selecting a zinc ion salt as a metal ion source, and selecting an aldehyde-functionalized silane coupling agent as an organic silane coupling agent, synthesizing a nano-silica MOF composite material by a solvent thermal method, and then performing surface modification with an aldehyde-functionalized silane coupling agent to obtain a composite adsorption material G, wherein the composite adsorption material G selectively and efficiently adsorbs glutamate through a Schiff base reaction between the surface aldehyde group and the amino group of glutamic acid;

[0032] Step 3, preparing a new catalyst, the new catalyst is composed of a transition metal oxide cobalt trioxide and a nitrate of a rare earth element lanthanum, weighing cobalt nitrate and lanthanum nitrate, respectively, dissolving them in deionized water, then stirring and dissolving, then mixing the two solutions together, and slowly dropping a precipitant sodium hydroxide solution to precipitate metal ions, filtering, washing and drying to obtain a catalyst precursor, then calcining the catalyst precursor to obtain a new catalyst with a specific structure and performance, then adding the catalyst to the fermentation broth to accelerate the chemical reaction between glutamate and the fermentation broth, generating an intermediate product that is beneficial to the preparation of fertilizers, and improving the nutrient content and stability of the fertilizers;

[0033] Step 4: introducing pressure-responsive polymer gel to treat the fermentation broth. First, raw materials for synthesizing pressure-responsive polymer gel are prepared, including hydroxyethyl methacrylate, ethylene glycol dimethacrylate and initiator azobisisobutyronitrile. Hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed and added to a reaction container filled with an organic solvent toluene, and stirred and mixed under a nitrogen environment. The initiator azobisisobutyronitrile is slowly added to the reaction system for reaction, and the pressure-responsive polymer gel is synthesized by free radical polymerization. In the ultrafiltration pretreatment stage, the synthesized polymer gel is placed in a treatment device, and the volume of the polymer gel is shrunk by applying pressure to the fermentation broth, glutamic acid is selectively adsorbed, and the ultrafiltration efficiency is improved. In the fertilizer preparation stage, the pressure is reduced to expand the volume of the polymer gel, release glutamic acid, and achieve precise regulation of glutamic acid.

[0034] Step 5: prepare the fertilizer formula to ensure that the ratio of nitrogen, phosphorus and potassium macroelements is N:P:K=3:2:3, and trace elements such as iron, zinc and copper are added at the same time, and the ratio of trace elements is iron:zinc:copper=1:0.5:0.3. Then, the ultrafiltered fermentation liquid is mixed with the fertilizer raw material. During the mixing process, the stirring speed is controlled at 50r / min to 100r / min. Subsequently, the fertilizer is subjected to deodorization technology, the prepared fertilizer is subjected to special treatment, and finally the fertilizer is packaged in sealed plastic bags.

[0035] In one embodiment of the present invention: in step 1, the pore size of the ultrafiltration membrane is 0.01 μm-0.1 μm, the material thereof is polyethersulfone, and the set pressure is 0.2 MPa-0.5 MPa.

[0036] In one embodiment of the present invention: In step 2, in the synthesis of the composite adsorbent material G, the surface of the nano-silica particles is pretreated with a silane coupling agent. In the pretreatment process, the nano-silica particles are first dispersed in an ethanol solution, and the silane coupling agent is added, and the reaction is stirred at 40°C-50°C for 3h-5h. After the reaction is completed, it is filtered, washed and dried at 80°C-100°C for 2h-3h, so that the surface of the nano-silica particles is connected with amino functional groups, so that it can be combined with nitrogen-containing organic ligands and metal ion sources in the solvent thermal reaction. The grafting rate of the aldehyde-functionalized silane coupling agent is 80%-90%, ensuring that the adsorption selectivity and adsorption capacity of glutamic acid per gram of adsorbent material reach 50㎎-80㎎ of glutamic acid.

[0037] In one embodiment of the present invention: in step three, during the preparation of the catalyst, the weighed amount of cobalt nitrate is 10g-20g, the weighed amount of lanthanum nitrate is 5g-10g, the amount of dissolved deionized water is 100ml-200ml respectively, the stirring temperature is 30℃-40℃, the stirring speed is 100r / min-150r / min, the dripping speed of the precipitant sodium hydroxide solution is 5ml-10ml per minute, the reaction temperature is 80℃-100℃, the reaction time is 6h-10h, the drying temperature is 80℃-100℃, the drying time is 4h-6h, the catalyst precursor calcination temperature is 400℃-600℃, and the calcination time is 4h-8h.

[0038] In one embodiment of the present invention: in step 4, the amount of hydroxyethyl methacrylate is 15g-25g, the amount of ethylene glycol dimethacrylate is 5g-15g, the amount of initiator azobisisobutyronitrile is 0.5g-1.5g, the amount of organic solvent toluene is 150ml-250ml, the stirring temperature is 30°C-40°C, the stirring time is 30min-60min, after adding the initiator, the reaction temperature is controlled to be 60°C-80°C, the reaction time is 8h-12h, the pressure applied to the fermentation liquid in the ultrafiltration pretreatment stage is 0.8MPa-1.2MPa, and the pressure in the fertilizer preparation stage is 0.1MPa-0.3MPa.

[0039] In one embodiment of the present invention: in step five, the deodorization technology adopts a method of activated carbon adsorption combined with biological deodorant spraying, the adsorption capacity of activated carbon is 50ml-80ml of odorous gas per gram of activated carbon, and the spraying amount of biological deodorant is 100ml-150ml per cubic meter of space, ensuring that the deodorization effect reaches more than 90% of the odorous gas removal rate.

[0040] In one embodiment of the present invention: in step 2, the nano-silica MOF composite material is synthesized by a solvothermal method, the synthesis temperature is 150° C.-200° C., and the synthesis time is 12 h-24 h.

[0041] In one embodiment of the present invention: in step five, when the ultrafiltered fermentation liquid is mixed with other fertilizer raw materials, the other fertilizer raw materials are first preheated at a temperature of 40°C-60°C for 20min-40min, and then during the stirring and mixing process, an intermittent stirring method is adopted, with a pause of 1min-2min every 5min-8min of stirring.

[0042] In one embodiment of the present invention: in step five, when the prepared fertilizer is subjected to special treatment, in addition to spraying a moisture-proof agent on the surface of the fertilizer, a vacuum drying treatment is also adopted, and the fertilizer is placed in a vacuum drying device, and the vacuum degree is controlled at -0.08MPa to -0.1MPa, the drying temperature is 50°C-70°C, and the drying time is 3h-5h, ensuring that the water content of the fertilizer is less than 5%, further improving the stability of the fertilizer, and preventing moisture absorption, caking and decomposition.

[0043] Example 1, please refer to the attached Figure 1 -Attached Figure 4First, the glutamate fermentation broth was preliminarily tested, and then an ultrafiltration membrane with a pore size of 0.1 μm and a material of polyethersulfone was used for ultrafiltration treatment at a pressure of 0.5 MPa to remove bacteria, protein and pigment impurities. Then, the composite adsorbent material G was prepared. Nano-silica particles with a particle size of 20 nm-50 nm were stirred and reacted in an ethanol solution at 50 ° C for 5 h with a silane coupling agent, filtered, washed and dried at 100 ° C for 3 h to attach amino functional groups, and then reacted with 2-aminoterephthalic acid and zinc ion salt by a solvothermal method at 180 ° C for 24 h to synthesize a nano-silica MOF composite material. It was then modified with an aldehyde-functionalized silane coupling agent to allow the aldehyde groups on its surface to undergo a Schiff base reaction with the amino groups of glutamic acid. At the same time, a new catalyst was prepared. 20 g of cobalt nitrate and 10 g of lanthanum nitrate were weighed and dissolved in 200 ml of deionized water respectively. The mixture was stirred at 40 ° C and 150 r / min to dissolve. After mixing, 10 ml of sodium hydroxide solution was slowly added dropwise per minute to precipitate metal ions. The mixture was reacted at 100 ° C for 10 h. The catalyst precursor was obtained by filtration, washing and drying at 100 ° C for 5 h. The new catalyst was calcined at 500 ° C for 7 h and added to the fermentation broth to accelerate the chemical reaction. Then, the pressure-responsive polymer gel was introduced. , prepare 25g of hydroxyethyl methacrylate, 15g of ethylene glycol dimethacrylate and 1.5g of azobisisobutyronitrile, mix the first two, add 250ml of toluene, stir for 60min at 40℃ under nitrogen environment, add initiator and react at 80℃ for 12h to synthesize gel, apply 1.2MPa pressure to the fermentation liquid in the ultrafiltration pretreatment stage to make the gel shrink and adsorb glutamate, reduce the pressure to 0.3MPa in the fertilizer preparation stage to make the gel swell and release glutamate, then prepare the fertilizer formula to ensure N:P:K=3:2:3, add iron, zinc and copper trace elements in a ratio of 1:0.5:0.3 The fermentation liquid after ultrafiltration is mixed with other fertilizer raw materials preheated to 60°C for 40 minutes by intermittent stirring (pause for 2 minutes every 8 minutes of stirring), and then deodorized by activated carbon adsorption combined with biological deodorant spraying (the spraying amount of biological deodorant is 150ml per cubic meter of space to ensure that the deodorization effect reaches more than 90%), and then the fertilizer is specially treated (moisture-proof agent is sprayed on the surface of the fertilizer and placed in a vacuum drying equipment, the vacuum degree is controlled at -0.1MPa, the drying temperature is 70°C, the drying time is 5h, and the water content is ensured to be less than 5%), and finally packaged in sealed plastic bags.

[0044] Example 2, please refer to the attached Figure 1 -Attached Figure 4First, the glutamate fermentation broth was preliminarily tested, and then an ultrafiltration membrane with a pore size of 0.1 μm and a material of polyethersulfone was used for ultrafiltration treatment at a pressure of 0.5 MPa to remove bacteria, protein and pigment impurities. Then, the composite adsorbent material H was prepared by preparing nano-titanium dioxide particles with a particle size of 30 nm-60 nm, 3-aminobenzoic acid as a nitrogen-containing organic ligand, copper ion salt as a metal ion source, and a carboxyl-functionalized silane coupling agent as an organic silane coupling agent. First, the nano-titanium dioxide particles were reacted with a silane coupling agent in an ethanol solution at 45°C for 4 hours with stirring, filtered, washed and dried at 90°C for 2.5 hours to attach carboxyl functional groups, and then reacted with 3-aminobenzoic acid and copper ion salts by a solvothermal method at 160°C for 18 hours to synthesize nano-titanium dioxide MOF composite materials. Finally, they were modified with a carboxyl-functionalized silane coupling agent to make the surface carboxyl groups interact weakly with the amino groups of glutamic acid. At the same time, a new catalyst was prepared. 18g of cobalt nitrate and 8g of lanthanum nitrate were weighed and dissolved in 180ml of deionized water. In deionized water, stir and dissolve at 35℃ and 120r / min. After mixing, slowly add 8ml of sodium hydroxide solution per minute to precipitate metal ions. React at 90℃ for 8h. After filtering, washing and drying at 90℃ for 4.5h, obtain a catalyst precursor. Calcined at 450℃ for 6h to obtain a new catalyst and add fermentation broth to accelerate the chemical reaction. Then introduce pressure-responsive polymer gel. Prepare 22g of hydroxyethyl methacrylate, 12g of ethylene glycol dimethacrylate and 1.2g of azobisisobutyronitrile. Mix the first two and add 220m l Toluene was stirred at 35℃ for 45min under nitrogen environment, and then reacted at 75℃ for 10h to synthesize gel after adding initiator. During the ultrafiltration pretreatment stage, 1.1MPa pressure was applied to the fermentation liquid to shrink the gel to adsorb glutamate. During the fertilizer preparation stage, the pressure was reduced to 0.25MPa to expand the gel to release glutamate. Then the fertilizer formula was prepared to ensure that N:P:K=3:2:3, and trace elements of iron, zinc, and copper were added in a ratio of 1:0.5:0.3. The ultrafiltered fermentation liquid was mixed with other fertilizers preheated to 55℃ for 35min. The raw materials are mixed by intermittent stirring (pause for 1.5 minutes every 7 minutes of stirring), and then deodorized by activated carbon adsorption combined with biological deodorant spraying (the spraying amount of biological deodorant is 130ml per cubic meter of space to ensure that the deodorization effect reaches more than 90%). The fertilizer is then specially treated (moisture-proof agent is sprayed on the surface of the fertilizer and placed in a vacuum drying equipment, the vacuum degree is controlled at -0.09MPa, the drying temperature is 65℃, the drying time is 4h, and the water content is ensured to be less than 5%), and finally packaged in sealed plastic bags.

[0045] Example 3, please refer to the attached Figure 1 -Attached Figure 4First, the glutamate fermentation broth was preliminarily tested, and then an ultrafiltration membrane with a pore size of 0.1 μm and a material of polyethersulfone was used for ultrafiltration treatment at a pressure of 0.5 MPa to remove bacteria, protein and pigment impurities. Then, the composite adsorbent material G was prepared. Nano-silica particles with a particle size of 20 nm-50 nm were stirred and reacted in an ethanol solution at 50 ° C for 5 h with a silane coupling agent, filtered, washed and dried at 100 ° C for 3 h to attach amino functional groups, and then reacted with 2-aminoterephthalic acid and zinc ion salt by a solvent thermal method at 180 ° C for 24 h to synthesize a nano-silica MOF composite material, and finally modified with an aldehyde-functionalized silane coupling agent to react the surface aldehyde groups with the glutamic acid amino groups to undergo a Schiff base reaction. At the same time, a new catalyst was prepared, using a single transition metal oxide copper oxide as a catalyst, weighing 30g of copper oxide and dissolving it in 300ml of deionized water, stirring and dissolving it at 50℃ at 200r / min, then adding a precipitant sodium carbonate solution, slowly dripping it at a rate of 15ml per minute to precipitate the metal ions, reacting it at 120℃ for 12h, filtering, washing and drying it at 120℃ for 6h to obtain a catalyst precursor, calcining it at 600℃ for 8h to obtain a catalyst and adding it to the fermentation broth to accelerate the chemical reaction, and then introducing a pressure-responsive polymer gel, preparing 25g of hydroxyethyl methacrylate, 15g of ethylene glycol dimethacrylate and 1.5g of azobisisobutyronitrile, mixing the first two and adding 250m l Toluene was stirred at 40℃ for 60min under nitrogen environment, and then reacted at 80℃ for 12h after adding initiator to synthesize gel. During the ultrafiltration pretreatment stage, 1.2MPa pressure was applied to the fermentation liquid to shrink the gel to adsorb glutamate. During the fertilizer preparation stage, the pressure was reduced to 0.3MPa to make the gel swell and release glutamate. Then the fertilizer formula was prepared to ensure that N:P:K=3:2:3, and trace elements of iron, zinc, and copper were added in a ratio of 1:0.5:0.3. The ultrafiltered fermentation liquid was mixed with other preheated to 60℃ for 40min. The fertilizer raw materials are mixed by intermittent stirring (pause for 2 minutes every 8 minutes of stirring), and then deodorized by activated carbon adsorption combined with biological deodorant spraying (the biological deodorant spraying amount is 150ml per cubic meter of space to ensure that the deodorization effect reaches more than 90%). The fertilizer is then specially treated (a moisture-proof agent is sprayed on the surface of the fertilizer and placed in a vacuum drying equipment, the vacuum degree is controlled at -0.1MPa, the drying temperature is 70℃, the drying time is 5h, and the water content is ensured to be less than 5%), and finally packaged in sealed plastic bags.

[0046] Design of the experiment:

[0047] Experimental materials: Fermentation broth samples: Glutamic acid fermentation broth from the same batch to ensure consistency of ingredients.

[0048] Experimental reagents Various chemical reagents used to prepare composite adsorption materials and catalysts, including nano-silica particles, nano-titanium dioxide particles, nitrogen-containing organic ligands (2-aminoterephthalic acid, 3-aminobenzoic acid, etc.), metal ion sources (zinc ion salts, copper ion salts, etc.), organic silane coupling agents (aldehyde functionalization, carboxyl functionalization, etc.), cobalt nitrate, lanthanum nitrate, copper oxide, etc.;

[0049] Other reagents used in fertilizer preparation, such as hydroxyethyl methacrylate, ethylene glycol dimethacrylate, azobisisobutyronitrile, toluene, activated carbon, biological deodorant, moisture-proof agent, etc.;

[0050] Instruments and Equipment

[0051] Ultrafiltration equipment, reactor, agitator, centrifuge, drying oven, high performance liquid chromatograph (HPLC), element analyzer, gas chromatography-mass spectrometer (GC-MS), plant incubator, electronic balance, acidity meter, etc.;

[0052] (I) Composite adsorption material performance test

[0053] Adsorption experiments

[0054] Embodiment 1:

[0055] Prepare composite adsorbent material G according to an established method;

[0056] Take multiple equal amounts of fermentation broth samples, each with 100 mL. Add 0.5 g of composite adsorption material G to each sample, and stir at 25°C and 100 r / min for 60 min to perform adsorption reaction;

[0057] After the reaction is completed, the adsorption material and the fermentation liquid are separated by centrifugation, and the supernatant is collected;

[0058] Embodiment 2

[0059] The composite adsorbent material H is prepared by the same method as that in Example 2;

[0060] Repeat the above adsorption experimental steps, using the same amount of fermentation broth and adsorption material H;

[0061] Embodiment 3

[0062] Since no changes were involved in the composite adsorption material, the same fermentation broth sample as above was taken without adding adsorption material as a control;

[0063] Glutamic acid and impurity detection

[0064] The content of glutamate in the supernatant was detected by high performance liquid chromatography (HPLC);

[0065] The types and contents of impurities in the supernatant were detected using an elemental analyzer and a gas chromatography-mass spectrometer (GC-MS);

[0066] (II) Catalyst performance test

[0067] Reaction experiment

[0068] Embodiment 1:

[0069] Prepare new catalysts according to established methods;

[0070] Take multiple equal amounts of fermentation broth samples, each with 100 mL, add 0.2 g of catalyst to each sample, and react at 40 °C for 4 h;

[0071] Embodiment 2

[0072] The catalyst of Example 2 was prepared according to the corresponding method;

[0073] Repeat the above reaction experimental steps, using the same amount of fermentation broth and catalyst;

[0074] Embodiment 3

[0075] To prepare the catalyst of Example 3, repeat the above reaction experimental steps;

[0076] Detection of product and amino acid changes;

[0077] High performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were used to detect the content of specific intermediates related to glutamate in the reaction products;

[0078] Detect changes in the content of other amino acids in the reaction system and evaluate adverse reactions;

[0079] (III) Fertilizer preparation and crop growth experiments

[0080] Fertilizer preparation

[0081] Embodiment 1:

[0082] According to the method of Example 1 in the claims, all steps including ultrafiltration, composite adsorption material treatment, catalyst treatment, pressure-responsive polymer gel treatment, fertilizer formulation, deodorization and special treatment are completed to prepare fertilizer;

[0083] Embodiment 2

[0084] Fertilizer preparation was carried out according to the method of Example 2;

[0085] Embodiment 3

[0086] Fertilizer preparation was carried out according to the method of Example 3;

[0087] Crop planting experiment

[0088] Select healthy wheat seedlings of the same variety and growth stage, 30 plants per group;

[0089] The seedlings were planted in pots filled with the same weight of soil, and the soil fertility was basically the same;

[0090] The fertilizers prepared in Example 1, Example 2 and Example 3 were applied to each group of seedlings, respectively, and the amount of fertilizer applied was in accordance with conventional standards;

[0091] Place the flower pots in a plant incubator and set the same environmental conditions such as light, temperature, humidity, etc.

[0092] Regularly observe and record the growth indicators of crops, including plant height, number of leaves, fresh weight, dry weight, etc., and continue to observe for a growth cycle;

[0093] As attached Figure 2 -Attached Figure 4 As shown, the experiment compares Examples 1, 2, and 3, and Example 1 has obvious advantages. Its composite adsorption material has a high glutamate adsorption rate and good impurity removal, and the catalyst has good selectivity and high efficiency and small adverse reactions. After being used in fertilizer preparation, the crop growth indicators are better than others, proving that Example 1 has excellent effects.

[0094] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of the present application can be appropriately combined.

[0095] Some aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may be referred to as "data blocks", "modules", "engines", "units", "components" or "systems". The processor may be one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DAPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, or combinations thereof. In addition, various aspects of the present application may be expressed as computer products located in one or more computer-readable media, which include computer-readable program codes. For example, computer-readable media may include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, tapes ...), optical disks (e.g., compact disks CDs, digital versatile disks DVDs ...), smart cards, and flash memory devices (e.g., cards, sticks, key drives ...).

[0096] A computer readable medium may include a propagated data signal containing computer program code, such as in baseband or as part of a carrier wave. The propagated signal may have a variety of manifestations, including electromagnetic, optical, etc., or a suitable combination. A computer readable medium may be any computer readable medium other than a computer readable storage medium, which can be connected to an instruction execution system, device or equipment to communicate, propagate or transmit the program for use. The program code located on the computer readable medium can be transmitted through any suitable medium, including radio, cable, fiber optic cable, radio frequency signal, or similar medium, or any combination of the above mediums.

[0097] Similarly, it should be noted that in order to simplify the description disclosed in this application, so as to help understand one or more embodiments of the invention, in the above description of the embodiments of the present application, sometimes multiple features are merged into one embodiment, drawing or description thereof. However, this disclosure method does not mean that the features required by the object of the present application are more than the features mentioned in the claims. In fact, the features of the embodiment are less than all the features of the single embodiment disclosed above. In some embodiments, numbers describing the number of components and attributes are used. It should be understood that such numbers used in the description of the embodiments are modified by the modifiers "about", "approximately" or "substantially" in some examples. Unless otherwise specified, "about", "approximately" or "substantially" indicates that the number allows a variation of ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and claims are approximate values, which may change according to the required features of individual embodiments. In some embodiments, the numerical parameters should take into account the specified significant digits and adopt the general method of retaining the digits. Although the numerical domains and parameters used to confirm the breadth of their range in some embodiments of the present application are approximate values, in specific embodiments, such numerical settings are as accurate as possible within the feasible range.

[0098] Although the present invention is disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing fertilizer based on ultrafiltration pretreatment of glutamic acid fermentation broth, characterized in that: The method for preparing the fertilizer specifically comprises the following steps: Step 1: Perform preliminary testing on the glutamic acid fermentation broth, and perform ultrafiltration treatment on the fermentation broth through an ultrafiltration membrane to remove bacterial cells, proteins and pigment impurities in the fermentation broth; Step 2, preparing a composite adsorbent material G, preparing nano-silica particles with a particle size of 20nm-50nm, selecting 2-aminoterephthalic acid as a nitrogen-containing organic ligand, selecting a zinc ion salt as a metal ion source, and selecting an aldehyde-functionalized silane coupling agent as an organic silane coupling agent, synthesizing a nano-silica MOF composite material by a solvent thermal method, and then performing surface modification with an aldehyde-functionalized silane coupling agent to obtain a composite adsorbent material G, wherein the composite adsorbent material G undergoes a Schiff base reaction with an amino group of glutamic acid through a surface aldehyde group; Step 3, preparing a new catalyst, the new catalyst is composed of transition metal oxide cobalt trioxide and rare earth element lanthanum nitrate, weighing cobalt nitrate and lanthanum nitrate, respectively, dissolving them in deionized water, then stirring and dissolving, then mixing the two solutions together, and slowly adding a precipitant sodium hydroxide solution to precipitate metal ions, filtering, washing and drying to obtain a catalyst precursor, then calcining the catalyst precursor to obtain a new catalyst, and then adding the catalyst to the fermentation broth to accelerate the chemical reaction between glutamic acid and the fermentation broth; Step 4: introducing pressure-responsive polymer gel to treat fermentation broth. First, raw materials for synthesizing pressure-responsive polymer gel, including hydroxyethyl methacrylate, ethylene glycol dimethacrylate and initiator azobisisobutyronitrile, are prepared. Hydroxyethyl methacrylate and ethylene glycol dimethacrylate are mixed and added to a reaction container filled with an organic solvent, toluene, and stirred and mixed under a nitrogen environment. The initiator azobisisobutyronitrile is slowly added to the reaction system for reaction, and the pressure-responsive polymer gel is synthesized through free radical polymerization. In the ultrafiltration pretreatment stage, the synthesized polymer gel is placed in a treatment device, and the volume of the polymer gel is shrunk by applying pressure to the fermentation broth. In the fertilizer preparation stage, the pressure is reduced to expand the volume of the polymer gel and release glutamic acid. Step 5: prepare the fertilizer formula to ensure that the ratio of nitrogen, phosphorus and potassium macroelements is N:P:K=3:2:3, and trace elements such as iron, zinc and copper are added at the same time, and the ratio of trace elements is iron:zinc:copper=1:0.5:0.

3. Then, the ultrafiltered fermentation liquid is mixed with the fertilizer raw material. During the mixing process, the stirring speed is controlled at 50r / min to 100r / min. Subsequently, the fertilizer is subjected to deodorization technology, the prepared fertilizer is subjected to special treatment, and finally the fertilizer is packaged in sealed plastic bags.

2. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step 1, the pore size of the ultrafiltration membrane is 0.01 μm-0.1 μm, the material thereof is polyethersulfone, and the set pressure is 0.2 MPa-0.5 MPa.

3. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step 2, in the synthesis of the composite adsorbent material G, the surface of the nano-silica particles is pretreated with a silane coupling agent. In the pretreatment process, the nano-silica particles are first dispersed in an ethanol solution, and the silane coupling agent is added, and the reaction is stirred at 40°C-50°C for 3h-5h. After the reaction is completed, it is filtered, washed and dried at 80°C-100°C for 2h-3h, so that the surface of the nano-silica particles is connected with amino functional groups, so that it can be combined with nitrogen-containing organic ligands and metal ion sources in the solvent thermal reaction.

4. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step three, during the preparation of the catalyst, the weighed amount of cobalt nitrate is 10g-20g, the weighed amount of lanthanum nitrate is 5g-10g, the amount of dissolved deionized water is 100ml-200ml respectively, the stirring temperature is 30°C-40°C, the stirring speed is 100r / min-150r / min, the dripping speed of the precipitant sodium hydroxide solution is 5ml-10ml per minute, the reaction temperature is 80°C-100°C, the reaction time is 6h-10h, the drying temperature is 80°C-100°C, the drying time is 4h-6h, the catalyst precursor calcination temperature is 400°C-600°C, and the calcination time is 4h-8h.

5. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step 4, the amount of hydroxyethyl methacrylate is 15g-25g, the amount of ethylene glycol dimethacrylate is 5g-15g, the amount of initiator azobisisobutyronitrile is 0.5g-1.5g, the amount of organic solvent toluene is 150ml-250ml, the stirring temperature is 30°C-40°C, the stirring time is 30min-60min, after adding the initiator, the reaction temperature is controlled to be 60°C-80°C, the reaction time is 8h-12h, the pressure applied to the fermentation liquid in the ultrafiltration pretreatment stage is 0.8MPa-1.2MPa, and the pressure in the fertilizer preparation stage is 0.1MPa-0.3MPa.

6. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In step five, the deodorization technology adopts a method of activated carbon adsorption combined with biological deodorant spraying. The adsorption capacity of activated carbon is 50ml-80ml of odorous gas per gram of activated carbon, and the spraying amount of biological deodorant is 100ml-150ml per cubic meter of space, ensuring that the deodorization effect reaches more than 90% of the odorous gas removal rate.

7. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step 2, the nano-silicon dioxide MOF composite material is synthesized by a solvothermal method, the synthesis temperature is 150° C.-200° C., and the synthesis time is 12 h-24 h.

8. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step 5, when the ultrafiltered fermentation liquid is mixed with other fertilizer raw materials, the other fertilizer raw materials are first preheated at a temperature of 40°C-60°C for 20min-40min. Then, during the stirring and mixing process, an intermittent stirring method is adopted, with a pause of 1min-2min every 5min-8min of stirring.

9. The method for preparing fertilizer by ultrafiltration pretreatment of glutamic acid fermentation broth according to claim 1, characterized in that: In the step 5, when the prepared fertilizer is subjected to special treatment, in addition to spraying a moisture-proof agent on the surface of the fertilizer, a vacuum drying treatment is also adopted. The fertilizer is placed in a vacuum drying device, the vacuum degree is controlled at -0.08MPa to -0.1MPa, the drying temperature is 50°C-70°C, and the drying time is 3h-5h, ensuring that the moisture content of the fertilizer is less than 5%.

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