Method for preparing fertilizer from glutamic acid fermentation liquor under assistance of microwaves

Abstract

The invention discloses a method for preparing a fertilizer from glutamic acid fermentation liquor under the assistance of microwaves, and relates to the technical field of fertilizer preparation, and the method has the advantages that the purity of the fertilizer is improved by adopting various materials and methods, and a filter screen coated with a polytetrafluoroethylene nano coating in a multi-stage filtering mode is adopted, so that the utilization rate of the fertilizer is improved. The low surface energy characteristic of polytetrafluoroethylene is utilized, grease impurities and macromolecular protein impurities are effectively repelled, a ceramic membrane filtering device further removes small-particle impurities, the purity of fermentation liquor is ensured, through specific cellulase, hemicellulase and laccase treatment, the cellulose and hemicellulose structures of the corn straw are changed, and the corn straw fermentation liquor is obtained. According to the preparation method, a substance with rich pore structures is formed, then the substance is activated by a low-temperature plasma technology, surface active sites are increased, the adsorption capacity to impurities is remarkably enhanced, the purity of the fertilizer is greatly improved through the synergistic effect of the materials, and the high quality of a fertilizer product is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, in particular to a method for preparing fertilizer from glutamic acid fermentation liquid by utilizing microwave assistance. Background Art

[0002] Glutamic acid fermentation broth is a common by-product in the fermentation industry. It contains rich nutrients such as amino acids, sugars, vitamins and minerals, and has potential value as a fertilizer. The use of glutamate fermentation broth to prepare fertilizers can not only realize the resource utilization of waste and reduce environmental pollution, but also provide a new type of organic fertilizer for agricultural production. However, the current technology for preparing fertilizers using glutamate fermentation broth still faces some challenges. First, the fermentation broth has a high content of impurities, including incompletely utilized substrates, microbial cell fragments and metabolites. These impurities will affect the quality and effect of the fertilizer, and require effective separation and purification methods;

[0003] The existing technology has certain defects. First, the existing technology is not precise enough in removing impurities, lacks similar adsorption materials and multi-stage filtration, and it is difficult to improve the purity of fertilizers, and the product quality is limited. Secondly, the existing technology lacks efficient and environmentally friendly means to treat wastewater and waste gas, pollutes the environment and has low efficiency. Thirdly, the existing technology has a slow reaction rate and low production efficiency. For this reason, we propose a method for preparing fertilizer from glutamate fermentation broth using microwaves. Summary of the invention

[0004] The object of the present invention is to provide a method for preparing fertilizer from glutamic acid fermentation liquid by utilizing microwave assistance.

[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 from glutamic acid fermentation liquid using microwave assistance, the method for preparing fertilizer specifically comprising the following steps:

[0006] Step 1, filtering the glutamic acid fermentation liquid, using multi-stage filtration for filtering, the first stage is coarse filtration, through the filter screen coated with nano-coating, coarse filtration and rejection of oil impurities and macromolecular protein impurities, removal of large particle impurities and organic impurities easily adsorbed on the filter screen surface, followed by a second stage of fine filtration, using a ceramic membrane filter device to remove small particle impurities, and introducing the glutamic acid fermentation liquid after the preliminary treatment into a quartz glass reaction container that is resistant to high pressure, corrosion-resistant and has good microwave permeability;

[0007] Step 2: Select corn stalks to prepare adsorption materials, preliminarily clean the corn stalks, then put the corn stalks into a crushing device for crushing, and then prepare an enzyme solution, the enzyme solution is composed of three enzymes: cellulase, hemicellulase and laccase, and the corn stalk particles are immersed in the enzyme solution and placed in a constant temperature shaking incubator for reaction. After the reaction is completed, the mixture is placed in an oven for drying, and then low-temperature plasma technology is used to activate it, so that more active sites are formed on its surface to enhance the adsorption capacity of impurities;

[0008] Step 3, transferring the treated fermentation broth to a microwave reaction device, and adding a composite catalyst based on layered double hydroxide (LDH). The synthesis of LDH first dissolves magnesium ions and aluminum ions in deionized water, then drips sodium hydroxide solution to adjust the pH value, and obtains LDH after a period of reaction. Then, the ion exchange method is used for functional modification, and the prepared LDH is immersed in a solution containing copper ions for reaction, and finally dried and ground into powder. The layered structure and catalytic active sites are used to accelerate the conversion of glutamate fermentation broth into fertilizer intermediates under the action of microwaves, and the broth is stirred during the reaction process;

[0009] Step 4: Collect samples of Dunaliella salina growing in a high-salinity environment from a high-salinity sea area, separate and purify the Dunaliella salina to obtain pure algae species, prepare a culture medium during the culture process, the culture medium components include seawater, sodium nitrate, potassium dihydrogen phosphate and magnesium sulfate, place the culture medium in a sterile culture container, inoculate the Dunaliella salina into the culture medium, pass the wastewater generated by the fertilizer intermediate through a bioreactor containing Dunaliella salina, allow the Dunaliella salina to absorb and decompose the organic matter therein, and at the same time pass the waste gas through a filter device equipped with Dunaliella salina to absorb harmful components in the waste gas, install a filter membrane made of degradable materials for filtration in the subsequent link of wastewater treatment, and use its special pore structure and surface chemical properties to further filter out tiny particles and residual impurities in the water, and perform biodegradation treatment on the filter membrane after use;

[0010] Step 5: blend the treated fertilizer intermediate, add nitrogen, phosphorus, potassium, trace nutrients and additives, and stir until uniform, then use ultrafiltration technology to further purify the blended liquid fertilizer to obtain a liquid fertilizer product.

[0011] As a further solution of the present invention: in the step 1, the pore size of the filter screen for the first stage coarse filtration is 0.8mm-1.0mm, the nano coating of the filter screen is a polytetrafluoroethylene nano coating, and the pore size of the second stage fine filtration ceramic membrane is 0.3mm-0.5mm.

[0012] As a further solution of the present invention: in the step 2, the corn stalks are put into a crushing device and crushed into particles of 120-180 mesh size, the mass ratio of cellulase, hemicellulase and laccase in the enzyme solution is 2.4-2.6:1.2-1.4:1.0-1.4, and the concentration of the enzyme solution is 8g / L-10g / L.

[0013] As a further solution of the present invention: in the step 2, the corn stalk particles are soaked in the enzyme solution and placed in a constant temperature shaking incubator, and the reaction is carried out for 4.0h-5.0h under the conditions of a temperature of 36°C-38°C, a pH value of 6.0-6.4, and an shaking frequency of 80-90 times per minute. After the reaction is completed, the particles are placed in an oven at 75°C-80°C for drying.

[0014] As a further solution of the present invention: in the step 2, the activation parameters are voltage 65kV-70kV, frequency 18kHz-20kHz, and processing time 18min-20min.

[0015] As a further scheme of the present invention: in the step three, the composite material catalyst of layered double hydroxide (LDH) is synthesized by a coprecipitation method, the synthesis temperature is 100°C-110°C, the magnesium ions and aluminum ions synthesized by LDH are dissolved in deionized water in a molar ratio of 2.2-2.4:1-1.3, sodium hydroxide solution is added to maintain the pH value of the solution at 9.3-9.6, the reaction time is 3.5h-3.7h, LDH is immersed in a copper ion solution, the copper ion concentration is 0.15mol / L-0.2mol / L, the reaction is carried out at a temperature of 42°C-45°C for 3.5h-3.8h, the microwave power is 650W-700w, the frequency is 2400MHz-2600MHz, the stirring speed during the reaction is 110r / min-120r / min, and the stirring time is 1.5h-2.0h.

[0016] As a further solution of the present invention: in step 4, the salinity of seawater in the culture medium is 12%-14%, the culture medium is placed in a sterile culture container, the temperature of the sterile culture container is 27°C-30°C, the light intensity is 2400lux-2800lux, and the pH value is 7.8-8.0.

[0017] As a further solution of the present invention: in the step 4, a filter membrane made of a degradable polylactic acid material is installed in the subsequent link of the wastewater treatment, and the pore size of the filter membrane is 0.35μm-0.50μm.

[0018] As a further solution of the present invention: in the step five, after adding the nutrients and additives, the stirring speed is 60r / min-80r / min and the stirring is carried out for 1.0h-1.5h. The pore size of the ultrafiltration membrane used in the ultrafiltration process is 0.05μm-0.1μm, and the operating pressure is 0.1MPa-0.3MPa.

[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 improves the purity of fertilizer by adopting a variety of innovative materials and methods. The filter screen coated with polytetrafluoroethylene nano-coating in the multi-stage filtration method utilizes the low surface energy characteristics of polytetrafluoroethylene to effectively repel oil impurities and large molecular protein impurities. The ceramic membrane filtration device further removes small particle impurities to ensure the purity of the fermentation liquid. Secondly, the new adsorption material prepared with corn stalks as raw materials plays a key role. Through the treatment of specific cellulase, hemicellulase and laccase, the cellulose and hemicellulose structures of corn stalks are changed to form a material with rich pore structure. After activation by low-temperature plasma technology, its surface active sites are increased and the adsorption capacity of impurities is significantly enhanced. The synergistic effect of these materials greatly improves the purity of fertilizers and ensures the high quality of fertilizer products.

[0021] 2. The present invention has good treatment capacity for wastewater and waste gas generated by fertilizer intermediates by growing Dunaliella salina in a high-salt environment. Its cell structure and physiological characteristics enable it to efficiently absorb and decompose organic matter in wastewater and harmful components in waste gas. At the same time, the filter membrane made of degradable polylactic acid material plays an important role in wastewater treatment. Polylactic acid material has good biodegradability and environmental compatibility. Its special pore structure and surface chemical properties can further filter tiny particles and residual impurities in water to ensure that wastewater meets discharge standards. This combination of special algae and degradable materials effectively reduces the pollution of wastewater and waste gas emissions to the environment and realizes the green and environmental protection of the fertilizer production process.

[0022] 3. The present invention prepares a composite material catalyst based on layered double hydroxide (LDH), synthesizes LDH with magnesium ions and aluminum ions in a specific ratio by coprecipitation method, so that it has a layered structure, providing a large number of active sites for the reaction, and then introduces copper ions into the LDH interlayer by ion exchange method, further enhancing its catalytic activity. Under the assistance of microwaves, this composite material catalyst can efficiently accelerate the reaction of converting glutamate fermentation broth into fertilizer intermediates. Microwaves can uniformly heat the reaction system, so that the reactant molecules obtain sufficient energy and fully contact with the active sites of the catalyst, thereby accelerating the reaction rate. The combination of this material and microwave technology effectively shortens the preparation cycle, improves production efficiency, reduces production costs, and provides a strong guarantee for the large-scale production of fertilizers. 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 Schematic diagram of performance comparison of embodiments of the present invention. DETAILED DESCRIPTION

[0025] 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.

[0026] 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.

[0027] Please see attached Figure 1 -Attached Figure 2 The present invention provides a method for preparing fertilizer from glutamic acid fermentation liquid using microwave assistance. The method for preparing fertilizer specifically comprises the following steps:

[0028] Step 1, filtering the glutamic acid fermentation liquid, using multi-stage filtration for filtering, the first stage is coarse filtration, through the filter screen coated with nano-coating, coarse filtration and rejection of oil impurities and macromolecular protein impurities, removal of large particle impurities and organic impurities easily adsorbed on the filter screen surface, followed by a second stage of fine filtration, using a ceramic membrane filter device to remove small particle impurities, and introducing the glutamic acid fermentation liquid after the preliminary treatment into a quartz glass reaction container that is resistant to high pressure, corrosion-resistant and has good microwave permeability;

[0029] Step 2: Select corn stalks to prepare adsorption materials, preliminarily clean the corn stalks, then put the corn stalks into a crushing device for crushing, and then prepare an enzyme solution, the enzyme solution is composed of three enzymes: cellulase, hemicellulase and laccase, and the corn stalk particles are immersed in the enzyme solution and placed in a constant temperature shaking incubator for reaction. After the reaction is completed, the mixture is placed in an oven for drying, and then low-temperature plasma technology is used to activate it, so that more active sites are formed on its surface to enhance the adsorption capacity of impurities;

[0030] Step 3, transferring the treated fermentation broth to a microwave reaction device, and adding a composite catalyst based on layered double hydroxide (LDH). The synthesis of LDH first dissolves magnesium ions and aluminum ions in deionized water, then drips sodium hydroxide solution to adjust the pH value, and obtains LDH after a period of reaction. Then, the ion exchange method is used for functional modification, and the prepared LDH is immersed in a solution containing copper ions for reaction, and finally dried and ground into powder. The layered structure and catalytic active sites are used to accelerate the conversion of glutamate fermentation broth into fertilizer intermediates under the action of microwaves, and the broth is stirred during the reaction process;

[0031] Step 4: Collect samples of Dunaliella salina growing in a high-salinity environment from a high-salinity sea area, separate and purify the Dunaliella salina to obtain pure algae species, prepare a culture medium during the culture process, the culture medium components include seawater, sodium nitrate, potassium dihydrogen phosphate and magnesium sulfate, place the culture medium in a sterile culture container, inoculate the Dunaliella salina into the culture medium, pass the wastewater generated by the fertilizer intermediate through a bioreactor containing Dunaliella salina, allow the Dunaliella salina to absorb and decompose the organic matter therein, and at the same time pass the waste gas through a filter device equipped with Dunaliella salina to absorb harmful components in the waste gas, install a filter membrane made of degradable materials for filtration in the subsequent link of wastewater treatment, and use its special pore structure and surface chemical properties to further filter out tiny particles and residual impurities in the water, and perform biodegradation treatment on the filter membrane after use;

[0032] Step 5: blend the treated fertilizer intermediate, add nitrogen, phosphorus, potassium, trace nutrients and additives, and stir until uniform, then use ultrafiltration technology to further purify the blended liquid fertilizer to obtain a liquid fertilizer product.

[0033] In one embodiment of the present invention: in step 1, the pore size of the filter screen for the first stage coarse filtration is 0.8mm-1.0mm, the nano-coating of the filter screen is a polytetrafluoroethylene nano-coating, and the pore size of the ceramic membrane for the second stage fine filtration is 0.3mm-0.5mm.

[0034] In one embodiment of the present invention: in step 2, corn stalks are put into a crushing device and crushed into particles of 120-180 mesh size, the mass ratio of cellulase, hemicellulase and laccase in the enzyme solution is 2.4-2.6:1.2-1.4:1.0-1.4, and the concentration of the enzyme solution is 8g / L-10g / L.

[0035] In one embodiment of the present invention: in step 2, the corn stalk particles are soaked in an enzyme solution and placed in a constant temperature shaking incubator, and the reaction is carried out for 4.0h-5.0h under the conditions of a temperature of 36°C-38°C, a pH value of 6.0-6.4, and an shaking frequency of 80-90 times per minute. After the reaction is completed, the particles are placed in an oven at 75°C-80°C for drying.

[0036] In one embodiment of the present invention: in step 2, the activation parameters are voltage 65kV-70kV, frequency 18kHz-20kHz, and processing time 18min-20min.

[0037] In one embodiment of the present invention: in step three, a composite material catalyst of a layered double hydroxide (LDH) is synthesized by a coprecipitation method, the synthesis temperature is 100°C-110°C, the magnesium ions and aluminum ions synthesized by LDH are dissolved in deionized water in a molar ratio of 2.2-2.4:1-1.3, sodium hydroxide solution is added to maintain the pH value of the solution at 9.3-9.6, the reaction time is 3.5h-3.7h, LDH is immersed in a solution of copper ions, the copper ion concentration is 0.15mol / L-0.2mol / L, the reaction is carried out at a temperature of 42°C-45°C for 3.5h-3.8h, the microwave power is 650W-700w, the frequency is 2400MHz-2600MHz, the stirring speed during the reaction is 110r / min-120r / min, and the stirring time is 1.5h-2.0h.

[0038] In one embodiment of the present invention: in step 4, the salinity of seawater in the culture medium is 12%-14%, the culture medium is placed in a sterile culture container, the temperature of the sterile culture container is 27°C-30°C, the light intensity is 2400lux-2800lux, and the pH value is 7.8-8.0.

[0039] In one embodiment of the present invention: in step 4, a filter membrane made of a degradable polylactic acid material is installed in the subsequent stage of wastewater treatment, and the pore size of the filter membrane is 0.35 μm-0.50 μm.

[0040] In one embodiment of the present invention: in step five, after adding the nutrients and additives, the stirring speed is 60r / min-80r / min and the stirring is for 1.0h-1.5h. The pore size of the ultrafiltration membrane used in the ultrafiltration process is 0.05μm-0.1μm, and the operating pressure is 0.1MPa-0.3MPa.

[0041] Example 1, please refer to the attached Figure 1 -Attached Figure 2First, the glutamic acid fermentation liquid is filtered and treated by multi-stage filtration. The first stage of coarse filtration is through a filter screen coated with polytetrafluoroethylene nano-coating and with a pore size of 0.8 mm to exclude oil and fat, large molecular protein impurities, large particle impurities and some organic impurities that are easily adsorbed on the filter screen surface. Then, the second stage of fine filtration uses a ceramic membrane filter device with a pore size of 0.3 mm to remove small particle impurities. The fermentation liquid after preliminary treatment is introduced into a quartz glass reaction container that is resistant to high pressure, corrosion and has good microwave permeability. Corn stalks are selected, crushed into particles of 180 mesh size after preliminary cleaning, and an enzyme solution composed of cellulase, hemicellulase and laccase in a mass ratio of 2.4:1.2:1.0 and a concentration of 8g / L is prepared. The corn stalk particles were soaked in an enzyme solution, placed in a constant temperature shaking incubator with a temperature of 38°C, a pH value of 6.0, and an oscillation frequency of 80 times per minute for reaction for 5.0 hours, and placed in an oven at 80°C for drying after the reaction was completed. The particles were then activated using a low-temperature plasma technology with a voltage of 65 kV, a frequency of 20 kHz, and a treatment time of 18 minutes to enhance the adsorption capacity of impurities. The fermentation liquid treated as above was transferred to a microwave reaction device, and a composite material catalyst based on layered double hydroxide (LDH) was added at the same time. The catalyst was synthesized by a coprecipitation method at 110°C. Magnesium ions and aluminum ions were dissolved in deionized water at a molar ratio of 2.2:1, and a sodium hydroxide solution was added to adjust the pH. The value was maintained at 9.6, and LDH was obtained after reacting for 3.5 hours. Then, the LDH was immersed in a copper ion solution with a concentration of 0.15 mol / L, reacted at a temperature of 45°C for 3.5 hours, and finally dried and ground into powder. Under a microwave power of 650 W and a frequency of 2400 MHz, the stirring speed of the reaction vessel was 110 r / min and the stirring time was 2.0 hours to accelerate the conversion of glutamate fermentation liquid into a fertilizer intermediate. Samples of Dunaliella salina were collected from high-salinity sea areas, and pure algae species were obtained after separation and purification. A culture medium containing seawater (salinity of 12%), sodium nitrate, potassium dihydrogen phosphate and magnesium sulfate was prepared and placed in a sterile culture container at a temperature of 30°C, a light intensity of 2800 lux and a pH value of 8.0. In the process, Dunaliella salina is inoculated and cultured to a certain biomass, the wastewater generated by the fertilizer intermediate is passed through a bioreactor containing Dunaliella salina to allow it to absorb and decompose organic matter, and the waste gas is passed through a filter device equipped with Dunaliella salina to absorb harmful components, and a filter membrane made of a degradable polylactic acid material with a pore size of 0.35 μm is installed in the subsequent stage of wastewater treatment to further filter out tiny particles and residual impurities, and the fertilizer intermediate is formulated, and after adding nitrogen, phosphorus, potassium, trace nutrients and additives, it is stirred at a stirring speed of 80 r / min for 1.5 hours, and then the ultrafiltration technology is used with an ultrafiltration membrane pore size of 0.1 μm and an operating pressure of 0.3 MPa to further purify the formulated liquid fertilizer to obtain a liquid fertilizer product.

[0042] Example 2, please refer to the attached Figure 1 -Attached Figure 2 First, the glutamic acid fermentation liquid is filtered and treated by multi-stage filtration. The first stage of coarse filtration is through a filter screen coated with a polyethylene nano-coating and a pore size of 0.8 mm to exclude some oils and some macromolecular impurities, large particle impurities and some organic impurities that are easily adsorbed on the surface of the filter screen. Then, the second stage of fine filtration uses a ceramic membrane filtration device with a pore size of 0.3 mm to remove small particle impurities. The fermentation liquid after preliminary treatment is introduced into a quartz glass reaction container that is resistant to high pressure, corrosion and has good microwave permeability. Wheat straw is selected and crushed into particles of 180 mesh size after preliminary cleaning. An enzyme solution composed of cellulase, hemicellulase and amylase in a mass ratio of 2.4:1.2:1.0 and a concentration of 8 g / L is prepared. The wheat straw particles are immersed in the enzyme solution and placed at a temperature of 400 °C. The fermentation liquid was placed in a constant temperature shaking incubator at 38°C, pH 6.0, and an oscillation frequency of 80 times per minute for 5.0 hours. After the reaction was completed, it was placed in an oven at 80°C for drying, and then activated by low-temperature plasma technology with a voltage of 65kV, a frequency of 20kHz, and a treatment time of 18min to enhance the adsorption capacity of impurities. The fermentation liquid treated as above was transferred to a microwave reaction device, and a composite material catalyst based on layered double hydroxide (LDH) was added at the same time. The catalyst was synthesized by a coprecipitation method at 110°C, and magnesium ions and aluminum ions were dissolved in deionized water at a molar ratio of 2.2:1. Sodium hydroxide solution was added to maintain the pH value at 9.6. The reaction was continued for 3.5 hours to obtain LDH, and then the LDH was immersed in a concentration of 0.15mo l / L zinc ion solution, react at a temperature of 45℃ for 3.5h, and finally dry and grind into powder. Under a microwave power of 650W and a frequency of 2400MHz, the stirring speed of the reaction container is 110r / min and the stirring time is 2.0h to accelerate the conversion of glutamate fermentation liquid into fertilizer intermediates. Samples of Dunaliella salina were collected from high-salinity sea areas, and pure algae species were obtained through separation and purification. A culture medium containing seawater (salinity of 12%), sodium nitrate, potassium dihydrogen phosphate and magnesium sulfate was prepared and placed at a temperature of 30℃ and a light intensity of 2800l ux, and a pH value of 8.0, Dunaliella salina is inoculated and cultured to a certain biomass, the wastewater generated by the fertilizer intermediate passes through a bioreactor containing Dunaliella salina to allow it to absorb and decompose organic matter, and the waste gas passes through a filter device equipped with Dunaliella salina to absorb harmful components, and a filter membrane made of a degradable polylactic acid material with a pore size of 0.35 μm is installed in the subsequent stage of wastewater treatment to further filter tiny particles and residual impurities, the fertilizer intermediate is formulated, and after adding nitrogen, phosphorus, potassium, trace nutrients and additives, it is stirred at a stirring speed of 80 r / min for 1.5 hours, and then the ultrafiltration technology is used, the ultrafiltration membrane has a pore size of 0.1 μm, and the operating pressure is 0.3 MPa to further purify the formulated liquid fertilizer to obtain a liquid fertilizer product.

[0043] Example 3, please refer to the attached Figure 1 -Attached Figure 2 First, the glutamic acid fermentation liquid is filtered and treated by multi-stage filtration. The first stage of coarse filtration is through a filter screen coated with polytetrafluoroethylene nano-coating and with a pore size of 0.8 mm to exclude oil and fat, large molecular protein impurities, large particle impurities and some organic impurities that are easily adsorbed on the surface of the filter screen. Then, the second stage of fine filtration uses a ceramic membrane filter device with a pore size of 0.3 mm to remove small particle impurities. The fermentation liquid after preliminary treatment is introduced into a quartz glass reaction container that is resistant to high pressure, corrosion and has good microwave permeability. Corn stalks are selected and crushed into particles of 180 mesh size after preliminary cleaning. An enzyme solution composed of cellulase, hemicellulase and laccase in a mass ratio of 2.4:1.2:1.0 and a concentration of 8 g / L is prepared. The corn stalk particles are immersed in the enzyme solution and placed at a temperature of 38°C, a pH value of 6.0, and an oscillation frequency of 80 per minute. The reaction was carried out in a constant temperature shaking incubator for 5.0 hours. After the reaction was completed, the mixture was placed in an oven at 80°C for drying. The mixture was then activated using a low-temperature plasma technology with a voltage of 65kV, a frequency of 20kHz, and a treatment time of 18min to enhance the adsorption capacity of impurities. The fermentation liquid treated as above was transferred to a microwave reaction device. The fermentation liquid was heated at 110°C using a conventional heating method and continuously stirred at a stirring speed of 110r / min for 2.0h to allow the glutamate fermentation liquid to react. However, the reaction rate and effect were not as ideal as when a composite material catalyst was used. Samples of Dunaliella salina were collected from high-salinity sea areas, and pure algae species were obtained by separation and purification. A culture medium containing seawater (salinity of 12%), sodium nitrate, potassium dihydrogen phosphate, and magnesium sulfate was prepared and placed at a temperature of 30°C and a light intensity of 2800l ux, and a pH value of 8.0, Dunaliella salina is inoculated and cultured to a certain biomass, the wastewater generated by the fertilizer intermediate passes through a bioreactor containing Dunaliella salina to allow it to absorb and decompose organic matter, and the waste gas passes through a filter device equipped with Dunaliella salina to absorb harmful components, and a filter membrane made of a degradable polylactic acid material with a pore size of 0.35 μm is installed in the subsequent stage of wastewater treatment to further filter tiny particles and residual impurities, the fertilizer intermediate is formulated, and after adding nitrogen, phosphorus, potassium, trace nutrients and additives, it is stirred at a stirring speed of 80 r / min for 1.5 hours, and then the ultrafiltration technology is used, the ultrafiltration membrane has a pore size of 0.1 μm, and the operating pressure is 0.3 MPa to further purify the formulated liquid fertilizer to obtain a liquid fertilizer product.

[0044] Example 4, please refer to the attached Figure 1 -Attached Figure 2First, the glutamic acid fermentation liquid was filtered and treated by multi-stage filtration. The first stage of coarse filtration was through a filter screen coated with a polytetrafluoroethylene nano-coating and a pore size of 0.8 mm to exclude oil and fat, large molecular protein impurities, large particle impurities and some organic impurities that are easily adsorbed on the filter screen surface. Then, the second stage of fine filtration used a ceramic membrane filter device with a pore size of 0.3 mm to remove small particle impurities. The fermentation liquid after preliminary treatment was introduced into a quartz glass reaction container that was resistant to high pressure, corrosion and had good microwave permeability. Corn stalks were selected and crushed into particles of 180 mesh size after preliminary cleaning. An enzyme solution composed of cellulase, hemicellulase and laccase in a mass ratio of 2.4:1.2:1.0 and a concentration of 8 g / L was prepared. The corn stalk particles were immersed in the enzyme solution and placed in a constant temperature shaking incubator with a temperature of 38°C, a pH value of 6.0 and an oscillation frequency of 80 times per minute for reaction for 5.0 hours. The reaction was completed. After being formed, it is placed in an oven at 80°C for drying treatment, and then activated by low-pressure plasma technology with a voltage of 65kV, a frequency of 20kHz, and a treatment time of 18min to enhance the adsorption capacity of impurities. The fermentation liquid treated as above is transferred to a microwave reaction device, and a metal oxide iron oxide catalyst is added at the same time. Under a microwave power of 650W and a frequency of 2400MHz, the stirring speed of the reaction container is 110r / min and the stirring time is 2.0h. However, since the activity of the catalyst is not as good as that of the composite material catalyst based on layered double hydroxide (LDH) in Example 1, the reaction rate of converting glutamate fermentation liquid into fertilizer intermediates is significantly slowed down. Samples of Dunaliella salina are collected from high-salinity sea areas, and pure algae species are obtained by separation and purification. A culture medium containing seawater (salinity of 12%), sodium nitrate, potassium dihydrogen phosphate and magnesium sulfate is prepared, and placed at a temperature of 30°C and a light intensity of 2800l ux, and a pH value of 8.0, Dunaliella salina is inoculated and cultured to a certain biomass, the wastewater generated by the fertilizer intermediate passes through a bioreactor containing Dunaliella salina to allow it to absorb and decompose organic matter, and the waste gas passes through a filter device equipped with Dunaliella salina to absorb harmful components, and a filter membrane made of a degradable polylactic acid material with a pore size of 0.35 μm is installed in the subsequent stage of wastewater treatment to further filter tiny particles and residual impurities, the fertilizer intermediate is formulated, and after adding nitrogen, phosphorus, potassium, trace nutrients and additives, it is stirred at a stirring speed of 80 r / min for 1.5 hours, and then the ultrafiltration technology is used, the ultrafiltration membrane has a pore size of 0.1 μm, and the operating pressure is 0.3 MPa to further purify the formulated liquid fertilizer to obtain a liquid fertilizer product.

[0045] Design of the experiment:

[0046] Experimental materials and equipment

[0047] 1. Several samples of glutamate fermentation broth;

[0048] 2. Various chemical reagents, enzymes, catalysts, materials, etc. required for the experiment, such as polytetrafluoroethylene nano-coated filter, polyethylene nano-coated filter, corn straw, wheat straw, various enzyme solutions, LDH composite catalyst, iron oxide catalyst, Dunaliella salina, etc., are prepared according to the requirements in the examples;

[0049] 3. Experimental equipment includes multi-stage filtration device, constant temperature shaking incubator, oven, microwave reaction device, conventional heating equipment, bioreactor, filtration membrane device, ultrafiltration equipment, high performance liquid chromatography (HPLC), laser particle size analyzer, chemical oxygen demand (COD) meter, biochemical oxygen demand (BOD) meter, total nitrogen (TN) meter, total phosphorus (TP) meter, gas analyzer, temperature sensor, stirring rate monitoring device, etc.;

[0050] Experimental method: Fertilizer purity testing

[0051] Impurity content analysis:

[0052] 1. For each fertilizer product treated in the embodiment, take an appropriate amount of sample and analyze it by high performance liquid chromatography (HPLC). First, dissolve the sample in an appropriate solvent to prepare a uniform solution; then, inject the solution into an HPLC instrument, compare the retention time and peak area of ​​different impurities in the chromatographic column with known standards, quantitatively determine the content of residual oil impurities, macromolecular protein impurities and other small molecular impurities, detect the size distribution of particles in the fertilizer product by a laser particle size analyzer, evenly disperse the sample in a liquid medium, pass it through a laser beam, analyze the size and distribution of the particles according to the intensity and angle changes of the scattered light, and evaluate the removal of tiny particle impurities;

[0053] Environmental pollution reduction assessment-wastewater treatment effect detection

[0054] 1. Before and after the wastewater treatment in each embodiment, water samples were collected. A chemical oxygen demand (COD) meter was used to measure the chemical oxygen demand in the water sample using the potassium dichromate method. Under acidic conditions, the organic matter in the water sample was oxidized by potassium dichromate. The COD value was calculated by measuring the amount of remaining potassium dichromate, and the COD reduction rate was then obtained. Similarly, a biochemical oxygen demand (BOD) meter, a total nitrogen (TN) meter, and a total phosphorus (TP) meter were used to measure the biochemical oxygen demand, total nitrogen, and total phosphorus content in the water sample according to the corresponding standard methods to comprehensively evaluate the wastewater treatment effect.

[0055] 2. Waste gas treatment effect detection

[0056] Before and after the exhaust gas passes through the corresponding treatment device, a gas analyzer is used to detect the harmful gas content in the exhaust gas.x ) and other harmful gases in the exhaust gas. The gas analyzer measures the concentration of each component in the gas through specific sensors and detection methods, and then calculates the harmful gas removal rate.

[0057] Reaction rate determination - reaction process monitoring

[0058] A temperature sensor and a stirring rate monitoring device are installed in a microwave reaction device or a conventional heating device. The temperature sensor records the temperature change during the reaction in real time to ensure that the reaction is carried out under the set temperature conditions. The stirring rate monitoring device monitors the stirring conditions during the reaction to ensure that the stirring speed meets the requirements of the embodiment.

[0059] Glutamate conversion rate assay

[0060] During the reaction, samples are taken regularly and chemically analyzed to determine the glutamic acid content therein. The conversion rate of glutamic acid is calculated based on the stoichiometric relationship of the chemical reaction using acid-base titration or other appropriate chemical analysis methods. The time required for the glutamic acid conversion rate to reach 50% is recorded as an evaluation indicator for the reaction rate.

[0061] As attached Figure 2 As shown, in terms of fertilizer purity, the impurity content of Example 1 is the lowest, because the polytetrafluoroethylene nano-coated filter screen used therein has a better rejection effect on oil and fat and macromolecular protein impurities, and the adsorption material prepared from corn stalks has a stronger adsorption capacity, and the impurities are removed more thoroughly after multi-stage filtration and adsorption treatment. In terms of the degree of environmental pollution reduction, the wastewater COD reduction rate and the exhaust gas harmful gas removal rate of Example 1 are the highest, thanks to the efficient absorption and decomposition of organic matter and harmful components in wastewater and exhaust gas by Dunaliella salina and the effective filtration of tiny particles and residual impurities by the filter membrane made of degradable polylactic acid material. In terms of reaction rate, Example 1 takes the shortest time to achieve the same glutamate conversion rate, because the composite catalyst based on layered double hydroxide (LDH) has a good layered structure and catalytic active sites, and can accelerate the reaction under microwave assistance, while the alternative materials or processes in other embodiments are not as good as Example 1 in catalytic activity or energy transfer efficiency.

[0062] 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 from glutamic acid fermentation liquid using microwave assistance, characterized in that: The method for preparing the fertilizer specifically comprises the following steps: Step 1, filtering the glutamic acid fermentation liquid, using multi-stage filtration for filtration, the first stage is coarse filtration, through a filter screen coated with a nano-coating, followed by a second stage of fine filtration, using a ceramic membrane filtration device to remove small particle impurities, and introducing the glutamic acid fermentation liquid after preliminary treatment into a quartz glass reaction container; Step 2: Select corn stalks to prepare adsorption materials, preliminarily clean the corn stalks, and then put the corn stalks into a crushing device for crushing, and then prepare an enzyme solution, the enzyme solution is composed of three enzymes: cellulase, hemicellulase and laccase, and the corn stalk particles are immersed in the enzyme solution and placed in a constant temperature shaking incubator for reaction. After the reaction is completed, the mixture is placed in an oven for drying, and then activated by low-temperature plasma technology; Step 3, transferring the treated fermentation broth to a microwave reaction device, and adding a composite material catalyst based on layered double hydroxide (LDH). The synthesis of LDH first dissolves magnesium ions and aluminum ions in deionized water, then drips sodium hydroxide solution to adjust the pH value, and obtains LDH after a period of reaction. Then, an ion exchange method is used for functional modification, and the prepared LDH is immersed in a solution containing copper ions for reaction, and finally dried and ground into powder. Subsequently, the glutamic acid fermentation broth is accelerated to be converted into a fertilizer intermediate under the action of microwaves, and it is stirred during the action process; Step 4: Collect samples of Dunaliella salina growing in a high-salinity environment from a high-salinity sea area, separate and purify the Dunaliella salina to obtain pure algae species, prepare a culture medium during the culture process, the culture medium components include seawater, sodium nitrate, potassium dihydrogen phosphate and magnesium sulfate, place the culture medium in a sterile culture container, inoculate the Dunaliella salina into the culture medium, pass the wastewater generated by the fertilizer intermediate through a bioreactor containing Dunaliella salina, allow the Dunaliella salina to absorb and decompose organic matter therein, and at the same time pass the waste gas through a filter device equipped with Dunaliella salina to absorb harmful components in the waste gas, install a filter membrane made of degradable materials in the subsequent link of wastewater treatment for filtration, and perform biodegradation treatment after use of the filter membrane; Step 5: blend the treated fertilizer intermediate, add nitrogen, phosphorus, potassium, trace nutrients and additives, and stir until uniform, then use ultrafiltration technology to further purify the blended liquid fertilizer to obtain a liquid fertilizer product.

2. The method for preparing fertilizer from glutamic acid fermentation liquid using microwave assistance according to claim 1, characterized in that: In the step 1, the pore size of the filter screen for the first stage coarse filtration is 0.8mm-1.0mm, the nano coating of the filter screen is a polytetrafluoroethylene nano coating, and the pore size of the ceramic membrane for the second stage fine filtration is 0.3mm-0.5mm.

3. The method for preparing fertilizer from glutamic acid fermentation liquid using microwaves as claimed in claim 1, characterized in that: In the step 2, the corn stalks are put into a pulverizing device and pulverized into particles of 120-180 meshes, the mass ratio of cellulase, hemicellulase and laccase in the enzyme solution is 2.4-2.6:1.2-1.4:1.0-1.4, and the concentration of the enzyme solution is 8g / L-10g / L.

4. The method for preparing fertilizer from glutamic acid fermentation liquid using microwave assistance according to claim 1, characterized in that: In the step 2, the corn stalk particles are soaked in the enzyme solution and placed in a constant temperature shaking incubator, and reacted for 4.0h-5.0h under the conditions of a temperature of 36°C-38°C, a pH value of 6.0-6.4, and an shaking frequency of 80-90 times per minute. After the reaction is completed, the particles are placed in an oven at 75°C-80°C for drying.

5. The method for preparing fertilizer from glutamic acid fermentation liquid using microwave assistance according to claim 1, characterized in that: In the step 2, the activation parameters are voltage 65 kV-70 kV, frequency 18 kHz-20 kHz, and processing time 18 min-20 min.

6. The method for preparing fertilizer from glutamic acid fermentation liquid using microwave assistance according to claim 1, characterized in that: In the step three, the composite material catalyst of layered double hydroxide (LDH) is synthesized by coprecipitation method, the synthesis temperature is 100°C-110°C, the magnesium ions and aluminum ions synthesized by LDH are dissolved in deionized water in a molar ratio of 2.2-2.4:1-1.3, sodium hydroxide solution is added to maintain the pH value of the solution at 9.3-9.6, the reaction time is 3.5h-3.7h, LDH is immersed in a copper ion solution, the copper ion concentration is 0.15mol / L-0.2mol / L, the reaction is carried out at a temperature of 42°C-45°C for 3.5h-3.8h, the microwave power is 650W-700w, the frequency is 2400MHz-2600MHz, the stirring speed is 110r / min-120r / min during the reaction, and the stirring time is 1.5h-2.0h.

7. The method for preparing fertilizer from glutamic acid fermentation liquid using microwaves as claimed in claim 1, characterized in that: In step 4, the salinity of seawater in the culture medium is 12%-14%, and the culture medium is placed in a sterile culture container. The temperature of the sterile culture container is 27° C.-30° C., the light intensity is 2400lux-2800lux, and the pH value is 7.8-8.

0.

8. The method for preparing fertilizer from glutamic acid fermentation liquid using microwaves as claimed in claim 1, characterized in that: In the step 4, a filter membrane made of degradable polylactic acid material is installed in the subsequent stage of wastewater treatment, and the pore size of the filter membrane is 0.35 μm-0.50 μm.

9. The method for preparing fertilizer from glutamic acid fermentation liquid using microwaves as claimed in claim 1, characterized in that: In the step five, after adding the nutrient elements and the additives, the stirring speed is 60r / min-80r / min and the stirring is carried out for 1.0h-1.5h. The pore size of the ultrafiltration membrane used in the ultrafiltration process is 0.05μm-0.1μm, and the operating pressure is 0.1MPa-0.3MPa.

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