How to make iron fulvic acid

Abstract

This is a method for producing iron fulvic acid, characterized in that cuttings of plants are added to hydrogen peroxide solution, and then iron nitrate is added and reacted. To provide a method for producing iron fulvic acid, which can efficiently produce iron fulvic acid in a short time under mild reaction conditions close to room temperature and atmospheric pressure.

Description

[Technical Field]

[0001] The present invention relates to a method for producing iron fulvate. [Background technology]

[0002] In nature, iron fulvic acid is one of the nutrients produced in humus, which is formed when plant leaves and stems humify. In an anaerobic environment, fulvic acid produced by humus chelates with iron ions from ferrous iron dissolved in water, producing iron fulvic acid. In the presence of dissolved oxygen, ferrous iron is oxidized to ferric iron and precipitates as hydroxide, but iron fulvic acid, which is formed by the combination of fulvic acid and iron ions, exists as a stable chelate compound and is transported to the sea by rivers, where it contributes to the growth of phytoplankton and seaweed.

[0003] One proposed method for producing iron fulvic acid includes a treatment step in which woody wood (and / or herbaceous wood) and iron material are used as main raw materials, and the woody wood is treated with steam at a temperature of 120 to 250°C and a pressure of 2 to 35 atm, and the herbaceous wood is treated with steam at a temperature of 100 to 200°C and a pressure of 2 to 25 atm while stirring the raw materials, to obtain a mixed solution containing iron hydroxide fulvic acid; and a fulvic acid solution obtaining step in which iron fulvic acid is separated from the obtained mixed solution to obtain an iron fulvic acid solution (see Patent Document 1). Furthermore, a method for producing humus containing iron fulvic acid has been proposed in which iron or a substance containing iron is added to and mixed with organic waste during the fermentation decomposition process of the organic waste (see Patent Document 2). Furthermore, in a method for treating activated sludge such as sewage, a method for producing iron fulvic acid has been proposed, which comprises the steps of obtaining fulvic acid powder using microorganisms, adding divalent and trivalent iron ions and an SH compound to the fulvic acid powder to form humus pellets, and injecting hydrogen peroxide into the humus pellets to cause an oxidation chain reaction (see Patent Document 3). In addition, a method has been proposed for producing iron fulvic acid material containing soluble silica by mixing a liquid substance consisting of silica iron with a fermented product in which fulvic acid has been produced by fermenting and sterilizing organic waste, and then causing a chelate reaction between the fulvic acid produced during the fermentation and sterilization process of the organic waste during the maturation process and the iron component of the silica iron (see Patent Document 4). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-129709 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-254450 [Patent Document 3] Japanese Patent Application Publication No. 6-39397 [Patent Document 4] International Publication WO2014 / 038596 Summary of the Invention [Problem to be solved by the invention]

[0005] With regard to the above-mentioned prior art, Patent Document 1 has a problem in that a sealed container or the like that can withstand high temperatures and pressures is required because the reaction is carried out at high temperatures and pressures. Furthermore, Patent Document 2 requires a fermentation decomposition process of organic waste, which poses a problem in that it takes a long time to produce iron fulvic acid. Furthermore, Patent Document 3 is a method for treating activated sludge such as sewage, and has the problem that each step requires a long period of time to achieve the effect of suppressing odor. Furthermore, similar to Patent Document 2, Patent Document 4 requires a fermentation decomposition process of wood chips, and therefore has the problem that it takes a long time to produce iron fulvate. Therefore, an object of the present invention is to provide a method for producing iron fulvic acid that can efficiently produce iron fulvic acid in a short time under mild reaction conditions close to room temperature and atmospheric pressure. [Means for solving the problem]

[0006] After extensive research, the inventors have found that the above-mentioned problems can be solved by adding cut pieces of plants to hydrogen peroxide solution, followed by the addition of iron nitrate, and allowing the reaction to proceed. The present invention was completed based on this finding.

[0007] That is, the present invention provides the following [1] to [7]. [1] A method for producing iron fulvic acid, characterized by reacting shredded pieces of plants, hydrogen peroxide, and iron nitrate. [2] A method for producing iron fulvic acid, which comprises adding shredded pieces of plants to hydrogen peroxide, then adding iron nitrate and allowing the mixture to react. [3] A method for producing iron fulvic acid, which comprises adding shredded pieces of plants to hydrogen peroxide solution, and then sequentially adding iron nitrate to cause a reaction. [4] The method for producing iron fulvate according to any one of [1] to [3] above, characterized in that a hydrogen peroxide solution having a concentration of 5% by weight or more and 40% by weight or less is used. [5] The method for producing iron fulvic acid according to any one of [1] to [4] above, characterized in that 0.2% by weight or more and 8.4% by weight or less of iron nitrate is used relative to the hydrogen peroxide solution. [6] A method for producing iron fulvate according to any one of [1] to [5] above, characterized in that the reaction is carried out at a reaction temperature of 5°C to 100°C for 12 hours to 48 hours. [7] The method for producing an iron fulvic acid extract according to any one of [1] to [6] above, wherein insoluble matter is removed from the reaction solution of iron fulvic acid. [Effects of the Invention]

[0008] According to the present invention, there is provided a method for producing iron fulvic acid efficiently in a short time under mild reaction conditions close to room temperature and pressure. Furthermore, according to the present invention, waste wood chips such as bark, sawdust, thinned wood, rice husks, and construction waste can be converted into iron fulvic acid, which is a useful substance, and thus the present invention can contribute to solving environmental issues by reducing waste through the upcycling of waste wood. This is an especially effective method for utilizing bark, which is generated in large quantities annually and whose use is limited to compost and the like. [Brief explanation of the drawings]

[0009] [Figure 1] Photographs showing the growth state of komatsuna 28 days after sowing. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the method for producing iron fulvic acid of the present invention will be described. [Method of producing iron fulvic acid] The method for producing iron fulvate of the present invention is characterized by reacting shredded pieces of plants with hydrogen peroxide and iron nitrate. In particular, it is preferable to add shredded pieces of plants to hydrogen peroxide, and then add iron nitrate and react them. Furthermore, it is preferable to add the cut pieces of plants to hydrogen peroxide solution, and then add iron nitrate successively to cause the reaction. The first step in the decomposition of trees (including grass and other plants) is for microorganisms to absorb easily decomposable sugars, amino acids, and starch, and then filamentous fungi and aerobic bacteria absorb proteins and other substances present inside the cells. Next, in the second stage, pectin, a component of plant cell walls, is further broken down, followed by the breakdown of dietary fiber hemiose and cellulose. In the final stage, the hardest and most difficult to decompose woody substances, such as lignin, begin to decompose. When lignin, a precursor to fulvic acid, is decomposed, the final decomposition product, fulvic acid, is produced.

[0011] The inventors focused on the oxidation chain reaction between hydrogen peroxide and iron nitrate in order to shorten a process that takes a long time in nature. 2+ ) and reacts with trivalent iron (Fe 3+ ) and hydroxyl radicals are generated. The strong oxidizing action of the generated hydroxyl radicals decomposes lignin and other substances. 3+ ) reacts with hydrogen peroxide to form ferrous iron (Fe 2+ ) and hydroperoxy radicals are generated. The generated hydroperoxy radicals decompose lignin and other substances in the same way as hydroxyl radicals. In addition, the inventors have found that by using iron nitrate, fulvic acid and bivalent iron (Fe 2+ ) to form a stable chelate compound, which can exist as an organic complex iron(II), and when applied to plants, it can be taken up by the plant's roots. Furthermore, the obtained fulvic acid iron extract contains sufficient nitrate ions, which can be taken up by plants. The absorbed iron and nitrogen elements are used to synthesize chlorophyll, which is essential for the light reaction of plant photosynthesis, and the nitrogen element is used to synthesize DNA, RNA, and amino acids in addition to chlorophyll, thereby promoting plant growth.

[0012] <Iron fulvic acid> Fulvic acid is a polymeric organic acid found in humic substances, the final product of microbial decomposition of plants and other materials, that does not precipitate with acid. It is widely distributed in soil and natural water. It is extracted from soil by adding an alkali or weak-acid salt to extract humic acid (humic acid) and then precipitating the humic acid. It does not have a single specific structural formula, but is a polyvalent organic acid containing many carboxyl and phenolic hydroxyl groups within its molecule. Fulvic acid can be produced by extraction from soil or natural water, by microbial fermentation of waste, or by reacting waste materials under high-temperature and high-pressure conditions in the presence of iron or other elements. Iron fulvic acid is a compound in which the carboxyl groups of fulvic acid and iron form a chelate. Iron fulvic acid is water-soluble and stable, and is useful as a nutrient for phytoplankton, algae such as kelp, and oyster farming, as well as a fertilizer for plants such as peanuts, sugarcane, and timber breeding.

[0013] In the present invention, iron fulvic acid is a general term for a group of substances with different molecular structures, as described above. Therefore, the commonly used definition is "fulvic acid is the component in humic substances that is soluble in alkaline and acidic solutions." Fulvic acid is measured using a conventionally used method. While there are measurement methods that focus on the stability of the iron chelate in iron fulvic acid, specifically, chemiluminescence analysis, stripping voltammetry, ICP-OES, ICP-MS, solid-phase analysis, or methods using nano-thin film test paper, it is difficult to accurately quantify the amount of chelated iron. Therefore, it is believed that iron fulvic acid is produced when fulvic acid and soluble iron are present in a solution.

[0014] In the present invention, "cut pieces of plants" include wood (lumber) and cut pieces of plants. <Wood (lumber) cuttings> Wood chips refer to cut bark, trunks, branches, or leaves, and can be in powder, granules, or chip form. Examples of chips include bark chips made from crushed pine bark, such as red pine and black pine, and various types of wood chips, such as those made from conifers like cypress, cedar, Japanese cypress, and camphor, as well as broad-leaved trees like cherry. Various sizes of cut pieces can be used depending on the manufacturing method. Also, sawdust, felled wood, or waste wood can be used, and felled wood can be either broad-leaved or coniferous. For example, broad-leaved trees include birch, and coniferous trees include cedar. Examples of waste wood include wood waste (such as lumber, boards, solid wood, laminated wood, and plywood (veneer)) generated during the demolition of wooden houses. While wood chips can be used as is, dried wood can also be used.

[0015] <Grass cuttings> In the present invention, cut grass can be used. Grass powder is also acceptable, but various sizes of cut pieces can be used depending on the production method. There are no particular restrictions on the type, but for example, cut grass plants can be used as the main raw material, and specific examples include rice, wheat, and barley, and parts that can be used include stalks (grasses), branches, leaves, and rice husks. The cut grass pieces can be used as is, but dried products can also be used. The device for shredding the plants is not particularly limited, and examples that can be used include a shredder for plants, a refiner, a wood grinder, etc. Furthermore, the "shredded pieces of plants" may be used as they are if they do not interfere with the reaction, such as leaves or rice husks.

[0016] <Iron nitrate> Iron nitrate can be used in either crystalline form, iron nitrate hexahydrate (Fe(NO3)2·6H2O) or iron nitrate nonahydrate (Fe(NO3)3·9H2O). There are no particular limitations on the amount of iron nitrate added, but a preferred amount is 0.2 to 8.4 wt% of iron nitrate (Fe(NO3)2) relative to the amount of hydrogen peroxide. At 0.2 wt% or more, the reaction proceeds sufficiently, while at 8.4 wt% or less, no problems arise with reactivity, including side reactions. From these perspectives, it is even more preferable for the amount of iron nitrate to be 0.2 to 2 wt%.

[0017] <Hydrogen peroxide solution> There are no particular limitations on the concentration of hydrogen peroxide solution, but it is preferable to use a hydrogen peroxide solution with a concentration of 5% by weight or more and 40% by weight or less, and more preferably a concentration of 25% by weight or more and 35% by weight or less. Although this varies depending on room temperature, a hydrogen peroxide solution with a concentration of 5% by weight or more can fully exert its functions, such as oxidizing power, and a hydrogen peroxide solution with a concentration of 40% by weight or less does not decompose into water and oxygen. Furthermore, a hydrogen peroxide solution with a concentration of 25% by weight or more and 35% by weight or less is even more desirable in terms of efficient production of iron fulvate.

[0018] <Reaction conditions> (Reaction temperature) There are no particular restrictions on the reaction temperature, but from the viewpoint of reaction rate, it is preferably 5°C or higher and 100°C or lower. If it is 5°C or higher, a sufficient reaction rate can be obtained, and if it is 100°C or lower, the reaction can be easily controlled. Furthermore, it is more preferably 40°C or higher and 50°C or lower, because the reaction state is stable and the reaction rate is fast. (Reaction time) The reaction time is preferably 12 hours or more and 48 hours or less. If the reaction time is 12 hours or more, the reaction will proceed sufficiently, while if the reaction time is 48 hours or less, the reaction will proceed sufficiently and high productivity will be maintained. (reaction pressure) There are no particular restrictions on the reaction pressure, provided that the vessel is made of a non-humic material, is temperature-controllable, and can be stirred, but for stable reaction, a pressure close to normal pressure is preferred. (addition order) In the reaction of shredded pieces of plant material, hydrogen peroxide solution, and iron nitrate, they may be mixed together and reacted, or either may be added first. However, to stabilize the reaction, it is more preferable to add the shredded pieces of plant material to the hydrogen peroxide solution and then add the iron nitrate, i.e., to add them sequentially and react them.

[0019] [Method of manufacturing fulvic acid iron extract] The present invention also encompasses a method for producing an iron fulvic acid extract by removing insoluble matter from the above-described iron fulvic acid reaction solution. The method for removing insoluble matter is not particularly limited as long as it can remove the insoluble matter, and for example, techniques such as precipitation, filtration, dialysis, ultrafiltration, gel filtration, etc. In the examples of the present invention, a simple filtration method using filter paper was used. The insoluble matter contains cellulose and the like and can be used for other purposes. [Example]

[0020] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0021] <Evaluation method> (Fulvic acid measurement) As mentioned above, humic substances (fulvic acid, humic acid, etc.) are not substances with a single chemical structure, but are a general term for a group of substances whose molecular structures vary depending on the humification process and raw materials. Therefore, there is no official method for identifying and quantifying fulvic acid. In the present invention, fulvic acid is defined as fulvic acid that is soluble in alkaline and acidic solutions in humic substances. The method for measuring fulvic acid was to confirm the presence of fulvic acid and measure its content according to the following procedure. (a) Extraction of alkali-soluble matter Sodium hydroxide solution was added to 100 mL of the measurement sample (fulvic acid iron extract) to make the concentration 0.1 M sodium hydroxide, and the alkali-soluble matter was extracted, and the supernatant was filtered off. (b) Fulvic acid fraction The supernatant was acidified by adding hydrochloric acid, and the resulting precipitate was filtered off, leaving a solution that was used as a fulvic acid solution. (c) Measurement of three-dimensional fluorescence spectrum The three-dimensional excitation-fluorescence spectrum of the above fulvic acid solution was measured. Excitation wavelengths (Ex) were measured between 200 and 500 nm, and fluorescence wavelengths (Em) were measured between 210 and 550 nm to obtain the three-dimensional excitation-fluorescence spectrum. The amount of fulvic acid contained in the fulvic acid solution was measured and calculated from the amount of fulvic acid in 100 mL of the measurement sample (iron fulvic acid extract).

[0022] (Measurement of iron content in fulvic acid) The iron content in the fulvic acid iron extract was measured by eluting the iron complex using an anion exchange resin column and then measuring the iron content by ICP atomic emission spectrometry.

[0023] Example 1 A 2-L four-neck flask was charged with 300 mL of 30% hydrogen peroxide solution. While stirring with a mechanical stirrer, 50 g of cedar stump chips (1 mm particle size) were added in small portions. After the chips were added, 1.8 g (0.6 wt%) of iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O) was added, taking care to avoid foaming and heat generation. The mixture was allowed to react at 45°C for 24 hours. Since unreacted hydrogen peroxide remained, iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O) was added to convert the unreacted hydrogen peroxide. The insoluble matter in the solution was then removed by suction filtration, yielding 300 mL of iron fulvic acid extract. The concentration of fulvic acid in the fulvic acid iron extract was 3.2 mg / mL (Dando fulvic acid equivalent). The iron in the fulvic acid iron extract was measured by eluting the iron complex using an anion exchange resin column and measuring the amount of iron using ICP atomic emission spectrometry, confirming the formation of fulvic acid iron.

[0024] Comparative Example 1 300 mL of iron fulvic acid extract was obtained in the same manner as in Example 1, except that 1.8 g of iron (II) sulfate heptahydrate (FeSO4·7H2O) was used.

[0025] The effects of the obtained iron fulvic acid extracts of Example 1 and Comparative Example 1 on the growth of Komatsuna were confirmed. Komatsuna seeds were sown in field soil, and 60 mL of a diluted solution prepared by diluting the iron fulvic acid extract obtained in Example 1 and Comparative Example 1 250 times with tap water was applied to the Komatsuna seedlings every 5 days, starting 7 days after sowing. As a control, Komatsuna plants were grown for 28 days under the same conditions, except that the 250-fold diluted iron fulvic acid extract was not applied.

[0026] The results are shown in Figure 1. As is clear from Figure 1 (a photograph of komatsuna 28 days after sowing), when comparing the 250-fold concentration of fulvic acid iron extract of Example 1 with the non-application area (control) and the application area of ​​Comparative Example 1, there was a significant difference in the growth of komatsuna, confirming the growth and development effect of fulvic acid iron extract using iron nitrate rather than ferrous sulfate.

[0027] Example 2 The same procedure as in Example 1 was repeated, except that 50 g of bark chips (manufactured by Ozaki Forest Products Co., Ltd., approximately 3 cm to 15 cm) crushed to an average particle size of 1 mm were used instead of 50 g of cedar stump wood chips (particle size 1 mm).The concentration of fulvic acid in the iron fulvic acid extract was 9.0 mg / mL (Dando fulvic acid equivalent).

[0028] Example 3 The same procedure was carried out as in Example 1, except that 50 g of cedar sawdust (manufactured by Shiny Works Co., Ltd.) crushed to an average particle size of 1 mm was used instead of 50 g of cedar stump wood chips (particle size 1 mm). The concentration of fulvic acid in the iron fulvic acid extract was 6.0 mg / mL (Dando fulvic acid equivalent). [Industrial Applicability]

[0029] The method for producing iron fulvic acid of the present invention does not require a high-temperature, high-pressure sealed container or a fermentation decomposition process in the production process of iron fulvic acid, and therefore is extremely simple and can stably produce iron fulvic acid in a short period of time. This method allows for the effective use of waste materials such as wood chips and rice straw, contributing to the creation of a recycling-oriented society. It also promotes the use of forest timber, contributing to forest development and the revitalization of mountain villages. Furthermore, by revitalizing forestry, it is possible to bring people back to satoyama (village forests) and maintain a rich natural balance, making it a valuable industrial technology.

Claims

1. A method for producing iron fulvic acid, characterized by reacting cuttings of plants, hydrogen peroxide solution, and iron nitrate.

2. A method for producing iron fulvic acid, comprising adding cut pieces of plants to hydrogen peroxide solution, and then adding iron nitrate to cause a reaction.

3. A method for producing iron fulvic acid, characterized in that cuttings of plants and trees are added to hydrogen peroxide solution, and then iron nitrate is successively added to cause a reaction.

4. The method for producing iron fulvate according to any one of claims 1 to 3, characterized in that a hydrogen peroxide solution having a concentration of 5% by weight or more and 40% by weight or less is used.

5. The method for producing iron fulvic acid according to any one of claims 1 to 3, characterized in that 0.2 wt% to 8.4 wt% of iron nitrate is used relative to the hydrogen peroxide solution.

6. The method for producing iron fulvate according to any one of claims 1 to 3, characterized in that the reaction is carried out at a reaction temperature of 5°C or higher and 100°C or lower for 12 hours or higher and 48 hours or lower.

7. The method for producing iron fulvic acid according to any one of claims 1 to 3, wherein insoluble matters are removed from a reaction solution of iron fulvic acid.

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