Method for quickly turning enteromorpha into fertilizer and product thereof

Abstract

The invention belongs to the technical field of biomass resource utilization, and discloses a method for rapid fertilization of enteromorpha and a product thereof, the method is characterized in that a humification reaction of enteromorpha is induced by using free radicals, the free radicals are generated by a reaction of a nano metal oxide and an oxidizing agent, and amplification is promoted by a biological enzyme; the nano metal oxide comprises nano iron oxide, the oxidizing agent comprises hydrogen peroxide, and the biological enzyme comprises laccase. Furthermore, after the product obtained by the method is dried, trace element mineral salt is added into the product, and the product enteromorpha fulvic acid trace element fertilizer is obtained. Through a system formed by the nano metal oxide, the oxidizing agent and the biological enzyme, the enteromorpha prolifera is quickly converted into a fertilizer, the fertilizer quality is improved, the environmental pollution is reduced, the resource utilization way of the enteromorpha prolifera is widened, and the marine ecological environment protection is promoted.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass resource utilization and relates to a method for quickly converting enteromorpha into fertilizer and a product thereof. Background Art

[0002] Enteromorpha is a green algae belonging to the Ulvaceae family. It is composed of a single layer of cells that can be enclosed into tubes or adhered into ribbons. In recent years, the explosive growth and rapid spread of Enteromorpha have caused serious harm to the marine ecological environment. At present, Enteromorpha is usually treated by salvaging it by fishing boats and then landfilling it, which is not only financially expensive, but also causes waste of resources and environmental pollution. Therefore, how to control Enteromorpha pollution and realize its resource utilization has become an important direction for improving the marine ecological environment. In addition, Enteromorpha has rich nutritional value, including protein, polysaccharides, crude fiber, amino acids and various minerals (such as iron, magnesium, potassium, sodium, zinc, calcium, phosphorus, etc.), and is a high-quality raw material for the preparation of highly active fertilizers.

[0003] At present, the resource utilization of Ulva is mainly concentrated in the fields of food, medicine, feed and low-value fertilizers. However, these utilization methods generally have problems such as long consumption cycle, small consumption, low added value, weak market competitiveness and low accuracy, and cannot meet the treatment and disposal needs brought about by the explosive growth and rapid spread of Ulva.

[0004] Currently, the preparation of fertilizer from Enteromorpha is mainly carried out through microbial fermentation or the addition of bacterial agents. For example, a patent application with application publication number CN101486612 discloses a method for producing seaweed fertilizer by treating Enteromorpha with microbial fermentation. This method uses fresh Enteromorpha as raw material without adding any chemicals. By preparing Enteromorpha seed liquid and fermenting Enteromorpha on a large scale, the effective components of Enteromorpha are dissolved, and the natural active ingredients in Enteromorpha are greatly retained. Various types of Enteromorpha seaweed fertilizers are prepared using this fermentation liquid as the base liquid.

[0005] For example, the patent application with application publication number CN116986932A discloses a method for preparing a Enteromorpha fertilizer synergist. The method involves large-scale fermentation of Enteromorpha with microorganisms such as Bacillus methylotrophicus LJ and Bacillus siamensis L13 to dissolve the effective ingredients of Enteromorpha, and then using Enteromorpha polysaccharide lyase to efficiently degrade the characteristic polysaccharides, proteins and cellulose in the Enteromorpha intercellular matrix and cell walls, fully releasing the nutritional elements inside the Enteromorpha, increasing the fermentation rate of Enteromorpha, and preparing a green algae-derived biostimulant.

[0006] However, preparing fertilizer from Enteromorpha through microbial fermentation or adding bacterial agents has disadvantages such as long cycle (usually takes 15 to 30 days), high carbon emissions (releases greenhouse gases such as CO2 and CH4), large footprint, and low fertilizer efficiency (fulvic acid content is less than 1%).

[0007] Therefore, it is necessary to develop a method for quickly converting enteromorpha into fertilizer and a product thereof to solve the above problems. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for quickly converting enteromorpha into fertilizer and a product thereof.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A method for rapidly converting Enteromorpha into fertilizer, using free radicals to induce a humification reaction in Enteromorpha to generate fulvic acid / humic acid substances, wherein the free radicals are generated by the reaction of nano-metal oxides and oxidants and are simultaneously amplified by biological enzymes;

[0011] The nano metal oxide includes nano iron oxide, the oxidant includes hydrogen peroxide, and the biological enzyme includes laccase.

[0012] Some prior arts utilize free radicals to induce humification reactions of non-enteromorpha raw materials to produce fulvic acid / humic acid substances. For example, prior arts utilize alkali / self-generated heat to activate potassium persulfate to generate free radicals to decompose lignin in sawdust and coffee grounds, and then synthesize fulvic acid / humic acid substances through high temperature / sulfate radical reaction. Another example is prior arts utilize alkali to activate persulfate to generate free radicals to polymerize sugar substances in sugarcane filter mud into fulvic acid / humic acid. However, these prior arts cannot be used to induce humification reactions of Enteromorpha using free radicals, because different organic substances require different free radicals for humification reactions (degradation first, then polymerization). A specific analysis is as follows:

[0013] The chemical structures of different organic compounds are complex and diverse, including chain, cyclic, aromatic, and aliphatic forms. These different structural forms determine the chemical bond breakage modes and reaction pathways that organic compounds may encounter during degradation. For example, when organic compounds containing ester bonds degrade, they generally require free radicals capable of attacking the ester bonds, such as hydrogen peroxide radicals or hydroxyl radicals, to effectively initiate the degradation reaction. Organic compounds containing carbon-carbon double or triple bonds, on the other hand, may require free radicals capable of undergoing addition reactions with them, such as alkyl radicals or halogen radicals, to achieve degradation. Furthermore, the precursors generated by the degradation of different organic compounds are equally complex and diverse, and these precursors may possess different functional groups and chemical properties. Therefore, it is impossible to simply use analogy or speculation to determine the specific inorganic free radical attack conditions that will produce organic free radicals after degradation, thereby initiating organic polymerization reactions to produce fulvic acid / humic acid substances. This process involves complex chemical reaction mechanisms and chain-like transmission of free radicals, requiring in-depth experimental research and theoretical analysis to draw accurate conclusions.

[0014] The reactivity of free radicals also varies depending on their structure and properties. The reactivity of free radicals mainly depends on the position and stability of their unpaired electrons, and different free radicals have different reactivity and selectivity. They may exhibit different reaction rates and reaction mechanisms when reacting with organic matter. For example, some free radicals may be more likely to attack specific chemical bonds in organic matter, while others may be more inclined to initiate chain reactions or branching reactions. Therefore, even for the same organic matter, different free radicals may lead to different degradation and polymerization products. This is why, when using free radicals to induce humification reactions in organic matter such as Enteromorpha, it is necessary to carefully screen and optimize the type of free radicals and reaction conditions to ensure that the target product, fulvic acid / humic acid, is obtained.

[0015] It is unknown what kind of free radicals are needed to induce the humification reaction in Enteromorpha and how these free radicals are generated. The present invention unexpectedly discovered that the free radicals generated by a system composed of nano-metal oxides including nano-iron oxide, an oxidant including hydrogen peroxide, and a biological enzyme including laccase can effectively induce the humification reaction in Enteromorpha. The specific principle is:

[0016] Fe in nano-iron oxide 2+ Reacts with hydrogen peroxide to generate hydroxyl radicals, superoxide radicals and hydrogen peroxide radicals, Fe 2+ Reduction to Fe 3+, while the metal Cu site in the laccase has a catalytic effect, improving the generation rate of hydroxyl radicals, superoxide radicals and hydrogen peroxide radicals. These inorganic free radicals have a strong oxidizing effect, attacking the polysaccharides, proteins and macromolecular carbohydrates in Enteromorpha, degrading them into small molecule monosaccharides, amino acids and fatty acids, etc. In this process, small molecule monosaccharides, amino acids, fatty acids, etc. become organic free radicals such as phenol groups, phenyl groups, and fatty chains, and polymerization reactions such as polyphenol-protein, sugar-amine reaction, and polyphenol self-condensation occur to generate fulvic acid / humic acid substances. The present invention adopts a chemical method to realize the rapid fertilizerization of Enteromorpha, solving a series of problems existing in the prior art that adopts a biological method to realize the fertilizerization of Enteromorpha.

[0017] As the preferred technical solution:

[0018] In the method for rapidly converting enteromorpha into fertilizer, the nano-metal oxide is nano-iron oxide, or a mixture of nano-iron oxide and nano-copper oxide in a mass ratio of 50-70:30-50; and the amount of the nano-metal oxide added is 5-15 wt% of the dry weight of enteromorpha.

[0019] In the method for rapidly converting Enteromorpha into fertilizer as described above, the oxidant is hydrogen peroxide, or a mixture of hydrogen peroxide and manganese oxide in a mass ratio of 60-80:20-40, or a mixture of potassium ferrate, hydrogen peroxide and manganese oxide in a mass ratio of 10-20:40-60:20-30; the amount of the oxidant added is 10-20 wt% of the dry weight of Enteromorpha.

[0020] The method for rapidly converting Enteromorpha into fertilizer as described above, wherein the biological enzyme is laccase, or a mixture of laccase and other enzymes in a mass ratio of 60-80:20-40, and the other enzymes are one or more of catalase, glucose oxidase and polyphenol oxidase; and the amount of the biological enzyme added is 10-20 wt% of the dry weight of Enteromorpha.

[0021] The method for rapidly converting enteromorpha into fertilizer as described above comprises the following steps:

[0022] (a) washing and crushing fresh Enteromorpha in sequence, wherein the Enteromorpha has a moisture content of 75-90 wt % and a mesh size of 2-10;

[0023] (b) adding nano-metal oxide to the product of step (a), stirring at a stirring rate of 500-700 r / min, and reacting for 15 min-1 h;

[0024] (c) adding an oxidant to the product of step (b), stirring uniformly at a stirring rate of 400-600 r / min, and reacting for 30 min-1 h. This reaction is an exothermic reaction, causing the reaction system to automatically heat up to 70-90° C.;

[0025] (d) adding a biological enzyme to the product of step (c), stirring evenly, and reacting for 1-2 hours to produce fulvic acid.

[0026] The method for rapidly converting enteromorpha into fertilizer as described above further comprises the following steps:

[0027] (e) drying the product of step (d), and then adding trace element mineral salts thereto to obtain Enteromorpha fulvic acid trace element fertilizer.

[0028] In the method for rapidly converting Enteromorpha into fertilizer as described above, the trace element mineral salt is one or more of iron sulfate, copper sulfate, zinc sulfate and manganese sulfate; and the added amount of the trace element mineral salt is 10-30 wt % of the dry weight of Enteromorpha.

[0029] The present invention also provides a Enteromorpha fulvic acid trace element fertilizer, which is prepared by the above-mentioned Enteromorpha rapid fertilizerization method, and has a fulvic acid content of 23-25wt% and a humic acid content of 18-20wt%.

[0030] Beneficial effects:

[0031] (1) The present invention successfully induces the humification reaction of Enteromorpha by utilizing a system composed of nano-metal oxides, oxidants and biological enzymes to generate fulvic acid / humic acid substances. This process realizes the rapid fertilizerization of Enteromorpha at the hourly level, significantly improves the treatment efficiency, and solves the problem of long fertilizerization cycle of Enteromorpha in the prior art.

[0032] (2) The fertilizer prepared by the method of the present invention has a high content of fulvic acid / humic acid and is significantly more effective than fertilizers prepared by traditional microbial fermentation or adding bacterial agents, which helps to improve soil fertility, promote crop growth, and increase agricultural production efficiency.

[0033] (3) Compared with the existing technology, the method of the present invention has low carbon emissions, occupies a small area, and reduces environmental pollution and resource waste. At the same time, because it uses a chemical method rather than a biological method, it shortens the fermentation time and avoids the odor and harmful substances that may be generated during the biological fermentation process, making it more environmentally friendly and energy-saving.

[0034] (4) The implementation of the present invention helps to reduce the harm of Enteromorpha to the marine ecological environment, promote the balance and sustainable development of the marine ecosystem, and provide new technical means and solutions for the protection of the marine ecological environment by efficiently utilizing Enteromorpha resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1The figures are pictures and three-dimensional fluorescence spectra of Enteromorpha before and after humification in Example 1 of the present invention; in the figure, a is a picture of fresh Enteromorpha in Example 1, b is a three-dimensional fluorescence spectra of Figure a, c is a picture of the Enteromorpha humification product obtained in step (2.4) of Example 1, and d is a three-dimensional fluorescence spectra of Figure c, wherein I and II are mixtures of amino acids and protein small molecules, III and V are mixtures of fulvic acid and humic acid, and IV is a soluble metabolite;

[0036] Figure 2 This is an infrared spectra of fresh Enteromorpha, Enteromorpha fulvic acid trace element fertilizer, fulvic acid standard sample, and 85 wt% mineral-source fulvic acid in Example 1 of the present invention; in the figure, a represents the biochemical fulvic acid standard sample, b represents fresh Enteromorpha, c represents Enteromorpha fulvic acid trace element fertilizer, and d represents 85 wt% mineral-source fulvic acid;

[0037] Figure 3 This is a fertilizer effect diagram of wheat hydroponically cultivated with different hydroponic nutrient solutions for 12 days according to the present invention; in the figure, the first row from top to bottom is a top view of wheat hydroponically cultivated with different hydroponic nutrient solutions for 12 days, the second row is a front view of wheat hydroponically cultivated with different hydroponic nutrient solutions for 12 days, and each row from left to right is a fertilizer effect diagram of control group 1 (using deionized water as fertilizer), control group 2 (using the humified product of Enteromorpha as fertilizer), control group 3 (using fresh Enteromorpha as fertilizer), control group 4 (using seaweed liquid as fertilizer), and the Enteromorpha fulvic acid trace element fertilizer in Example 1 as fertilizer for hydroponic incubation of wheat;

[0038] Figure 4 This is a diagram showing the fertilizer efficiency of wheat hydroponically cultured using different hydroponic nutrient solutions for 12 days. DETAILED DESCRIPTION

[0039] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0040] The following are the test methods for the relevant performance indicators in each embodiment and comparative example:

[0041] Fulvic acid content: The Enteromorpha fulvic acid trace element fertilizer prepared in each example was used as a sample, and then the fulvic acid content of the sample was determined according to the NY / T 3162-2017 "Determination of fulvic acid in fertilizers - Volumetric titration method".

[0042] Humic acid content: The Enteromorpha humic acid trace element fertilizer prepared in each example was used as a sample, and then the humic acid content in the sample was determined according to NY / T1971-2010 "Determination of Humic Acid Content of Water-soluble Fertilizers".

[0043] The following are the sources of the substances in the examples:

[0044] Laccase: The manufacturer is Shanghai Yuanye Biotechnology Co., Ltd., CAS number is 80498-15-3, product number is S10189, and the product specification is 120 U / g;

[0045] Catalase: Manufacturer: Inotech Co., Ltd., CAS number: 9001-05-2, product number: C163049, specification: ≥200,000 units g;

[0046] Glucose oxidase: Manufacturer: Shanghai Yuanye Biotechnology Co., Ltd., CAS number: 9001-37-0, product number: S10021, product specification: 10,000 GODU / g;

[0047] Polyphenol oxidase: The manufacturer is Shanghai Yuanye Biotechnology Co., Ltd., CAS number is 9002-10-2, product number is S22800, and product specification is 1000u / mg solid.

[0048] In the following embodiments, all operations without explicit temperature conditions are assumed to be performed at room temperature, which is in the range of 22-25°C.

[0049] Example 1

[0050] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0051] (1) Preparation of raw materials;

[0052] Fresh Enteromorpha;

[0053] Oxidant: hydrogen peroxide;

[0054] Nano metal oxides: nano iron oxide, particle size 50-100nm;

[0055] Biological enzyme: laccase;

[0056] Trace element mineral salts: iron sulfate;

[0057] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0058] (2.1) The fresh Enteromorpha (the picture before Enteromorpha humification and the three-dimensional fluorescence analysis picture are shown in the figure) were taken in turn. Figure 1 Middle a, Figure 1b) is washed and crushed, at which time the water content of the enteromorpha is 90 wt % and the mesh size is 2;

[0059] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 700 r / min, and reacting for 1 hour; wherein the amount of nano-metal oxide added is 15 wt% of the dry weight of Enteromorpha;

[0060] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 400 r / min, and reacting for 15 minutes; wherein the amount of the oxidant added is 20 wt% of the dry weight of Enteromorpha;

[0061] (2.4) Add biological enzyme to the product of step (2.3), stir evenly, and react for 2 hours to obtain a humified product. The picture and three-dimensional fluorescence analysis diagram of the humified product are as follows: Figure 1 Middle C, Figure 1 As shown in d, from Figure 1 It can be seen that the main components of Enteromorpha before humification are amino acids, protein small molecules and soluble metabolites. After the humification reaction, the content of fulvic acid and humic acid substances increases, indicating that Enteromorpha contains rich fulvic acid and humic acid substances after humification. Among them, the amount of biological enzyme added is 20wt% of the dry weight of Enteromorpha.

[0062] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 30 wt% of the dry weight of Enteromorpha.

[0063] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 24 wt% and a humic acid content of 20 wt%;

[0064] The Enteromorpha fulvic acid trace element fertilizer prepared above, the fresh Enteromorpha in step (1), the biochemical fulvic acid standard sample and the mineral fulvic acid were subjected to infrared spectrum test, and the test results are as follows: Figure 2 As shown in the figure, it can be seen that the Enteromorpha fulvic acid trace element fertilizer prepared above contains C=O, C=C, CN, and NH functional groups, which have similar chemical bonds and functional groups to the biochemical fulvic acid standard sample (manufacturer is Shanghai Bid Pharmaceutical Technology Co., Ltd., purity is 99%) and mineral source fulvic acid (manufacturer is Hebei Yuanben Biotechnology Co., Ltd., purity ≥99%). In addition, compared with Enteromorpha, the C=C bond is also increased to a certain extent, indicating that the product after the humification reaction contains more aromatized substances; in addition, compared with fresh Enteromorpha, the CN bond and NH bond in Enteromorpha fulvic acid trace element fertilizer are also significantly increased, indicating that the Maillard reaction also occurs during the humification process, proving the formation of fulvic acid and humic acid.

[0065] The above-mentioned Enteromorpha fulvic acid trace element fertilizer is used to hydroponically incubate wheat, and the specific steps are as follows:

[0066] (a) preparing a hydroponic nutrient solution;

[0067] The prepared Enteromorpha fulvic acid trace element fertilizer was dissolved in deionized water, mixed evenly, and prepared into a hydroponic nutrient solution with a concentration of 50 mg / L;

[0068] (b) treating wheat seeds;

[0069] Wheat seeds (manufactured by Beijing Jingyan Yinong Seed Technology Co., Ltd.) were first soaked in tap water for 24 h in the dark, then sterilized with a 70% ethanol solution, and finally rinsed with deionized water for later use.

[0070] (c) hydroponic incubation;

[0071] An 11 cm culture dish is used as a container for hydroponic wheat cultivation. Two filter papers are placed at the bottom of the culture dish, and the wheat seeds treated in step (b) are placed on the filter papers at intervals. 15 mL of the hydroponic nutrient solution prepared in step (a) is added thereto. Finally, the culture dish is placed in an artificial incubator and cultured for 12 days at a temperature of 25° C. and a humidity of 50%. The culture dish contains 9 wheat seeds, and 20 mL of deionized water is added to the culture dish every other day during the culture process. The light period in the artificial incubator is 9:00-21:00, and the dark period is 21:00-9:00.

[0072] After 12 days of hydroponic culture, the fresh weight, plant height, root length and chlorophyll content of each wheat in the culture dish were measured. Finally, the average values ​​were calculated. It was found that after 12 days of hydroponic culture, the average fresh weight of the wheat was 1.78 g, the average plant height was 10.23 cm, the average root length was 9.87 cm, and the average chlorophyll content (SPAD) was 32.12.

[0073] Then 4 control groups were compared with the above hydroponic results, and the 4 control groups were as follows:

[0074] Control group 1: The steps for hydroponic incubation of wheat were basically the same as the above process, except that the enteromorpha fulvic acid trace element fertilizer was replaced with an equal mass of deionized water;

[0075] After 12 days of hydroponic cultivation, the average fresh weight of wheat was 1.3 g, the average plant height was 6.2 cm, the average root length was 4.7 cm, and the average chlorophyll content (SPAD) was 10;

[0076] Control group 2: The steps of hydroponic incubation of wheat were basically the same as the above process, except that the Enteromorpha fulvic acid trace element fertilizer was replaced with an equal mass of the Enteromorpha humified product obtained in step (2.4) of Example 1 above;

[0077] After 12 days of hydroponic cultivation, the average fresh weight of wheat was 1.4 g, the average plant height was 8 cm, the average root length was 8.5 cm, and the average chlorophyll content (SPAD) was 16;

[0078] Control group 3: The steps for hydroponic incubation of wheat were basically the same as the above process, except that the Enteromorpha fulvic acid trace element fertilizer was replaced with Enteromorpha of equal mass;

[0079] After 12 days of hydroponic cultivation, the average fresh weight of wheat was 1.1 g, the average plant height was 5.8 cm, the average root length was 3.8 cm, and the average chlorophyll content (SPAD) was 6;

[0080] Control group 4: The steps for hydroponic incubation of wheat were basically the same as the above process, except that the Enteromorpha fulvic acid trace element fertilizer was replaced with an equal mass of alginic acid; wherein the alginic acid was obtained by extracting the Enteromorpha using a 0.1 mol / L Na2CO3 aqueous solution;

[0081] After 12 days of hydroponic cultivation, the average fresh weight of wheat was 1 g, the average plant height was 5.6 cm, the average root length was 5.1 cm, and the average chlorophyll content (SPAD) was 18;

[0082] The results of the above hydroponic culture are as follows Figure 3 、 Figure 4 As shown in the figure, it can be seen that the Enteromorpha humic acid trace element fertilizer prepared by the present invention is more conducive to promoting wheat growth and has a more significant growth-promoting effect.

[0083] Example 2

[0084] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0085] (1) Preparation of raw materials;

[0086] Fresh Enteromorpha;

[0087] Oxidant: a mixture of hydrogen peroxide and manganese oxide in a mass ratio of 60:40;

[0088] Nano-metal oxide: a mixture of nano-iron oxide (particle size 50-100nm) and nano-copper oxide (particle size 50-100nm) in a mass ratio of 50:50;

[0089] Biological enzyme: a mixture of laccase and catalase in a mass ratio of 60:40;

[0090] Trace element mineral salts: copper sulfate;

[0091] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0092] (2.1) Washing and crushing fresh Enteromorpha in sequence, wherein the Enteromorpha has a moisture content of 75 wt % and a mesh size of 4;

[0093] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 600 r / min, and reacting for 45 minutes; wherein the amount of nano-metal oxide added is 10 wt% of the dry weight of Enteromorpha;

[0094] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 420 r / min, and reacting for 20 minutes; wherein the amount of the oxidant added is 15 wt% of the dry weight of Enteromorpha;

[0095] (2.4) adding a biological enzyme to the product of step (2.3), stirring evenly, and reacting for 1.5 hours to obtain a humified product; wherein the amount of the biological enzyme added is 15 wt% of the dry weight of Enteromorpha;

[0096] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 25 wt% of the dry weight of Enteromorpha.

[0097] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 25 wt % and a humic acid content of 18.5 wt %.

[0098] Comparative Example 1

[0099] A method for preparing a fertilizer is basically the same as that of Example 2, except that the nano-iron oxide in step (1) and step (2.2) is completely replaced by nano-copper oxide of equal mass.

[0100] The final fertilizer has a fulvic acid content of 12 wt % and a humic acid content of 3 wt %.

[0101] Comparing Comparative Example 1 with Example 2, it can be seen that the content of fulvic acid and humic acid in the fertilizer prepared in this comparative example is significantly reduced. This is because nano copper oxide cannot be as strong as Fe in nano iron oxide. 2+Doing so will react with hydrogen peroxide to generate hydroxyl radicals, superoxide radicals and peroxide radicals. The different types of free radicals cannot effectively attack the polysaccharides, proteins and large molecular carbohydrates in the Enteromorpha, causing them to degrade into small molecular monosaccharides, amino acids and fatty acids, etc., and thus cannot produce enough organic free radicals to trigger polymerization reactions such as polyphenol-protein, sugar-amine reactions, and polyphenol self-condensation, resulting in reduced production of fulvic acid and humic acid substances.

[0102] Comparative Example 2

[0103] A method for preparing a fertilizer is basically the same as that of Example 2, except that the hydrogen peroxide in step (1) and step (2.3) is completely replaced by an equal mass of manganese oxide.

[0104] The final fertilizer has a fulvic acid content of 8 wt % and a humic acid content of 4.5 wt %.

[0105] Comparing Comparative Example 2 with Example 2, it can be seen that the content of fulvic acid and humic acid in the fertilizer prepared in this comparative example is significantly reduced. This is because manganese oxide cannot react with Fe in nano-iron oxide like hydrogen peroxide. 2+ The reaction generates hydroxyl radicals, superoxide radicals and peroxide radicals, and the free radical production pathway changes, resulting in insufficient number of effective free radicals that can attack the polysaccharides, proteins and large molecular carbohydrates in Enteromorpha, and they cannot fully degrade them into small molecular monosaccharides, amino acids and fatty acids, etc. The subsequent formation of organic free radicals is limited, and it is difficult for polymerization reactions such as polyphenol-protein, sugar-amine reactions, and polyphenol self-condensation to occur smoothly, thereby reducing the production of fulvic acid and humic acid substances.

[0106] Comparative Example 3

[0107] A method for preparing a fertilizer is basically the same as that in Example 2, except that the laccase in step (1) and step (2.4) is completely replaced by an equal mass of catalase (the same as in Example 2).

[0108] The final fertilizer has a fulvic acid content of 10 wt % and a humic acid content of 3.5 wt %.

[0109] Comparing Comparative Example 3 with Example 2, it can be seen that the fulvic acid content and humic acid content of the fertilizer prepared in this comparative example are significantly reduced. This is because the main function of catalase is to catalyze the decomposition of hydrogen peroxide into water and oxygen, which is different from the function of laccase. The metal Cu site in laccase can increase the generation rate of hydroxyl radicals, superoxide radicals and hydrogen peroxide radicals, while catalase cannot play a similar catalytic role, resulting in a decrease in the effective free radical generation rate in the system, which is insufficient to efficiently attack the polysaccharides, proteins and macromolecular carbohydrates in Enteromorpha, limiting their degradation degree, generating less small molecular monosaccharides, amino acids and fatty acids, and thus making it difficult to generate sufficient organic free radicals for polymerization reaction, ultimately reducing the production of fulvic acid and humic acid substances.

[0110] Example 3

[0111] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0112] (1) Preparation of raw materials;

[0113] Fresh Enteromorpha;

[0114] Oxidant: a mixture of hydrogen peroxide and manganese oxide in a mass ratio of 80:20;

[0115] Nano-metal oxide: a mixture of nano-iron oxide (particle size 50-100 nm) and nano-copper oxide (particle size 50-100 nm) in a mass ratio of 70:30;

[0116] Biological enzyme: a mixture of laccase and glucose oxidase in a mass ratio of 70:30;

[0117] Trace element mineral salts: zinc sulfate;

[0118] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0119] (2.1) Washing and crushing fresh Enteromorpha in sequence, where the Enteromorpha has a moisture content of 85 wt% and a mesh size of 6;

[0120] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 550 r / min, and reacting for 50 minutes; wherein the amount of nano-metal oxide added is 10 wt% of the dry weight of Enteromorpha;

[0121] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 450 r / min, and reacting for 25 minutes; wherein the amount of the oxidant added is 15 wt% of the dry weight of Enteromorpha;

[0122] (2.4) adding a biological enzyme to the product of step (2.3), stirring evenly, and reacting for 1.5 hours to obtain a humified product; wherein the amount of the biological enzyme added is 15 wt% of the dry weight of Enteromorpha;

[0123] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 20 wt% of the dry weight of Enteromorpha.

[0124] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 23 wt % and a humic acid content of 19 wt %.

[0125] Example 4

[0126] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0127] (1) Preparation of raw materials;

[0128] Fresh Enteromorpha;

[0129] Oxidant: a mixture of potassium ferrate, hydrogen peroxide, and manganese oxide in a mass ratio of 10:60:20;

[0130] Nano metal oxides: nano iron oxide, particle size 50-100nm;

[0131] Biological enzyme: a mixture of laccase and polyphenol oxidase in a mass ratio of 80:20;

[0132] Trace element mineral salts: manganese sulfate;

[0133] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0134] (2.1) Washing and crushing fresh Enteromorpha in sequence, wherein the Enteromorpha has a moisture content of 80 wt % and a mesh size of 10;

[0135] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 600 r / min, and reacting for 30 minutes; wherein the amount of nano-metal oxide added is 10 wt% of the dry weight of Enteromorpha;

[0136] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 500 r / min, and reacting for 1 hour; wherein the amount of the oxidant added is 15 wt% of the dry weight of Enteromorpha;

[0137] (2.4) adding a biological enzyme to the product of step (2.3), stirring evenly, and reacting for 1.5 hours to obtain a humified product; wherein the amount of the biological enzyme added is 15 wt% of the dry weight of Enteromorpha;

[0138] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 20 wt% of the dry weight of Enteromorpha.

[0139] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 24 wt % and a humic acid content of 18.5 wt %.

[0140] Example 5

[0141] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0142] (1) Preparation of raw materials;

[0143] Fresh Enteromorpha;

[0144] Oxidant: a mixture of potassium ferrate, hydrogen peroxide, and manganese oxide in a mass ratio of 20:40:30;

[0145] Nano metal oxides: nano iron oxide, particle size 50-100nm;

[0146] Biological enzyme: laccase;

[0147] Trace element mineral salts: a mixture of iron sulfate and copper sulfate in a mass ratio of 1:1;

[0148] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0149] (2.1) Washing and crushing fresh Enteromorpha in sequence, where the Enteromorpha has a moisture content of 80 wt% and a mesh size of 8;

[0150] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 500 r / min, and reacting for 30 minutes; wherein the amount of nano-metal oxide added is 5 wt% of the dry weight of Enteromorpha;

[0151] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 550 r / min, and reacting for 40 minutes; wherein the amount of the oxidant added is 10 wt% of the dry weight of Enteromorpha;

[0152] (2.4) adding a biological enzyme to the product of step (2.3), stirring evenly, and reacting for 1 hour to obtain a humified product; wherein the amount of the biological enzyme added is 10 wt% of the dry weight of Enteromorpha;

[0153] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 10 wt% of the dry weight of Enteromorpha.

[0154] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 25 wt % and a humic acid content of 18.5 wt %.

[0155] Example 6

[0156] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0157] (1) Preparation of raw materials;

[0158] Fresh Enteromorpha;

[0159] Oxidant: a mixture of hydrogen peroxide and manganese oxide in a mass ratio of 70:30;

[0160] Nano-metal oxide: a mixture of nano-iron oxide (particle size 50-100 nm) and nano-copper oxide (particle size 50-100 nm) in a mass ratio of 60:40;

[0161] Biological enzyme: laccase;

[0162] Trace element mineral salts: iron sulfate;

[0163] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0164] (2.1) Washing and crushing fresh Enteromorpha in sequence, where the Enteromorpha has a moisture content of 80 wt% and a mesh size of 5;

[0165] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 600 r / min, and reacting for 40 minutes; wherein the amount of nano-metal oxide added is 15 wt% of the dry weight of Enteromorpha;

[0166] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 560 r / min, and reacting for 1 hour; wherein the amount of the oxidant added is 15 wt% of the dry weight of Enteromorpha;

[0167] (2.4) adding a biological enzyme to the product of step (2.3), stirring evenly, and reacting for 1.5 hours to obtain a humified product; wherein the amount of the biological enzyme added is 15 wt% of the dry weight of Enteromorpha;

[0168] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 20 wt% of the dry weight of Enteromorpha.

[0169] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 22 wt % and a humic acid content of 18 wt %.

[0170] Example 7

[0171] A method for preparing enteromorpha fulvic acid trace element fertilizer, comprising the following specific steps:

[0172] (1) Preparation of raw materials;

[0173] Fresh Enteromorpha;

[0174] Oxidant: a mixture of potassium ferrate, hydrogen peroxide, and manganese oxide in a mass ratio of 15:50:25;

[0175] Nano metal oxides: nano iron oxide, particle size 50-100nm;

[0176] Biological enzyme: laccase;

[0177] Trace element mineral salts: iron sulfate;

[0178] (2) preparing enteromorpha fulvic acid trace element fertilizer;

[0179] (2.1) Washing and crushing fresh Enteromorpha in sequence, where the Enteromorpha has a moisture content of 80 wt% and a mesh size of 5;

[0180] (2.2) adding nano-metal oxide to the product of step (2.1), stirring at a stirring rate of 600 r / min, and reacting for 40 minutes; wherein the amount of nano-metal oxide added is 10 wt% of the dry weight of Enteromorpha;

[0181] (2.3) adding an oxidant to the product of step (2.2), stirring at a stirring rate of 600 r / min, and reacting for 1 hour; wherein the amount of the oxidant added is 15 wt% of the dry weight of Enteromorpha;

[0182] (2.4) adding a biological enzyme to the product of step (2.3), stirring evenly, and reacting for 1 hour to obtain a humified product; wherein the amount of the biological enzyme added is 20 wt% of the dry weight of Enteromorpha;

[0183] (2.5) After drying the product of step (2.4), trace element mineral salts are added thereto to obtain Enteromorpha fulvic acid trace element fertilizer; wherein the amount of trace element mineral salts added is 30 wt% of the dry weight of Enteromorpha.

[0184] The finally prepared Enteromorpha fulvic acid trace element fertilizer has a fulvic acid content of 23 wt % and a humic acid content of 19.5 wt %.

Claims

1. A method for rapidly converting enteromorpha into fertilizer, characterized in that: The free radicals are used to induce the humification reaction of Enteromorpha, wherein the free radicals are generated by the reaction of nano-metal oxides and oxidants, and are amplified by biological enzymes. The nano metal oxide includes nano iron oxide, the oxidant includes hydrogen peroxide, and the biological enzyme includes laccase.

2. The method for rapidly converting enteromorpha into fertilizer according to claim 1, characterized in that: The nano metal oxide is nano iron oxide, or a mixture of nano iron oxide and nano copper oxide in a mass ratio of 50-70:30-50; the added amount of the nano metal oxide is 5-15wt% of the dry weight of Enteromorpha.

3. The method for rapidly converting enteromorpha into fertilizer according to claim 1, characterized in that: The oxidant is hydrogen peroxide, or a mixture of hydrogen peroxide and manganese oxide in a mass ratio of 60-80:20-40, or a mixture of potassium ferrate, hydrogen peroxide and manganese oxide in a mass ratio of 10-20:40-60:20-30; the added amount of the oxidant is 10-20wt% of the dry weight of Enteromorpha.

4. The method for rapidly converting enteromorpha into fertilizer according to claim 1, characterized in that: The biological enzyme is laccase, or a mixture of laccase and other enzymes in a mass ratio of 60-80:20-40, and the other enzymes are one or more of catalase, glucose oxidase and polyphenol oxidase; the added amount of the biological enzyme is 10-20wt% of the dry weight of Enteromorpha.

5. The method for rapidly converting enteromorpha into fertilizer according to any one of claims 1 to 4, characterized in that: The following steps are involved: (a) washing and crushing fresh Enteromorpha in sequence; (b) adding nano-metal oxide to the product of step (a), stirring evenly, and reacting for 15 min-1 h; (c) adding an oxidant to the product of step (b), stirring evenly, and reacting for 30 min-1 h; (d) adding a biological enzyme to the product of step (c), stirring evenly, and reacting for 1-2 hours.

6. The method for rapidly converting enteromorpha into fertilizer according to claim 5, characterized in that: The following steps are also included: (e) drying the product of step (d), and then adding trace element mineral salts thereto to obtain Enteromorpha fulvic acid trace element fertilizer.

7. The method for rapidly converting enteromorpha into fertilizer according to claim 6, characterized in that: The trace element mineral salt is one or more of iron sulfate, copper sulfate, zinc sulfate and manganese sulfate; the added amount of the trace element mineral salt is 10-30wt% of the dry weight of Enteromorpha.

8. A Enteromorpha fulvic acid trace element fertilizer, characterized in that: The method for rapidly converting enteromorpha into fertilizer as claimed in claim 6 or 7 is used to prepare the fulvic acid, and the fulvic acid content is 23-25 ​​wt%.

Images