Method for producing fulvic acid iron

Abstract

Disclosed is a method for producing fulvic acid iron, the method being characterized by adding cut pieces of plants to a hydrogen peroxide solution and subsequently adding iron nitrate to the solution so as to cause a reaction therebetween.　The present invention can provide a method for producing fulvic acid iron, with which it is possible to efficiently produce fulvic acid iron in a short time under mild reaction conditions that are close to normal temperature and normal pressure.

Description

How to make iron fulvic acid

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

[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 is to use woody wood (and / or herbaceous wood) and iron materials as main raw materials, and to subject the woody wood and herbaceous wood to subcritical water treatment with steam at a temperature of 120 to 250°C and a pressure of 2 to 35 atm, while stirring the raw materials, and another proposed method for producing iron fulvic acid is to subject the herbaceous wood and herbaceous wood to subcritical water treatment with steam at a temperature of 120 to 250°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 another proposed method for producing an iron fulvic acid solution is to separate the iron fulvic acid from the mixed solution to obtain an iron fulvic acid solution (see Patent Document 1). Another proposed method for producing humus containing iron fulvic acid involves adding and mixing iron or an iron-containing substance with organic waste during the fermentation decomposition process of organic waste (see Patent Document 2). Furthermore, a method for producing iron fulvic acid in a treatment method for activated sludge such as sewage 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). Another method has been proposed for producing an iron fulvic acid material containing soluble silica by mixing a liquid substance containing iron silica 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 and the iron component of the iron silica system (see Patent Document 4).

[0004] JP 2019-129709 A JP 2012-254450 A JP 6-39397 A International Publication WO2014 / 038596

[0005] With regard to the above-mentioned prior art, Patent Document 1 has a problem in that a reaction is carried out at high temperature and pressure, and therefore a sealed container or the like capable of withstanding high temperature and pressure is required. Patent Document 2 also has a problem in that a fermentation decomposition process of organic waste is required, and therefore a long time is required to produce iron fulvic acid. Patent Document 3 is a method for treating activated sludge from sewage or the like, and therefore a long time is required for each step to achieve the effect of odor suppression. Patent Document 4, like Patent Document 2, also has a problem in that a fermentation decomposition process of wood chips is required, and therefore a long time is required to produce iron fulvic acid. 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 normal pressure.

[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, which comprises reacting shredded pieces of plants with hydrogen peroxide and iron nitrate. [2] A method for producing iron fulvic acid, which comprises adding shredded pieces of plants to hydrogen peroxide, followed by adding iron nitrate and allowing the reaction to proceed. [3] A method for producing iron fulvic acid, which comprises adding shredded pieces of plants to hydrogen peroxide, followed by sequentially adding iron nitrate and allowing the reaction to proceed. [4] A method for producing iron fulvic acid according to any of [1] to [3] above, which uses hydrogen peroxide at a concentration of 5% by weight to 40% by weight. [5] A method for producing iron fulvic acid according to any of [1] to [4] above, which uses iron nitrate at a concentration of 0.2% by weight to 8.4% by weight relative to the hydrogen peroxide. [6] A method for producing iron fulvic acid according to any of [1] to [5] above, which comprises reacting 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.

[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.

[0009] 1 is a photograph showing the state of growth of komatsuna 28 days after sowing.

[0010] An embodiment of the method for producing iron fulvic acid of the present invention is described below. [Method for producing iron fulvic acid] The method for producing iron fulvic acid of the present invention is characterized by reacting shredded pieces of plant material with hydrogen peroxide and iron nitrate. In particular, it is preferable to add shredded pieces of plant material to hydrogen peroxide, then add iron nitrate and allow the reaction to proceed. Furthermore, it is preferable to add shredded pieces of plant material to hydrogen peroxide, then sequentially add iron nitrate and allow the reaction to proceed. In the first stage of decomposition of trees (including plants such as grasses), microorganisms absorb easily decomposable sugars, amino acids, and starch. Next, filamentous fungi and aerobic bacteria absorb proteins and other intracellular substances. Next, in the second stage, pectin, a component of plant cell walls, is further decomposed, followed by the decomposition of dietary fiber hemiose and cellulose. In the final stage, decomposition of lignin, the hardest and most difficult-to-decompose woody element, begins. When lignin, a precursor to fulvic acid, is decomposed, the final decomposition product, fulvic acid, is produced.

[0011] The inventors focused on the chain reaction of oxidation between hydrogen peroxide and iron nitrate in order to shorten a process that would normally take 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 the like in the same way as hydroxyl radicals. The inventor has also discovered that by using iron nitrate, fulvic acid and divalent iron (Fe ２＋They found that fulvic acid iron forms a stable chelate compound with nitrate, which can exist as an organic complex iron(II). When applied to plants, this can be absorbed by the plant's roots. Furthermore, the resulting iron fulvic acid extract contains sufficient nitrate ions, which can be absorbed by the plant. 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 high-molecular-weight organic acid that does not precipitate with acid, among the humic substances that are the final product of microbial decomposition of plants and other materials. It is widely distributed in soil and natural waters. It is extracted from soil by co-extracting with humic acid (humic acid) using an alkali or weak acid salt, followed by the addition of an acid to precipitate the humic acid. It does not have a specific structural formula and 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, microbial fermentation of waste materials, or reaction of 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, making it 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.

[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 vegetation" refers to trees (lumber) and cut pieces of vegetation. <Cut pieces of wood (lumber)> Wood pieces refer to cut pieces of bark, trunks, branches, leaves, etc., and can be used in powder, granules, or chip form. Examples of chips include bark chips made from crushed pine bark such as red pine and black pine, various types of wood chips such as coniferous trees such as cypress, cedar, Japanese cypress, and camphor tree, and broadleaf trees such as cherry. Cut pieces can be used in a variety of sizes depending on the production method. In addition, sawdust, felled wood, or waste wood can be used, and felled wood can be either broadleaf or coniferous trees. For example, broadleaf trees include birch, and coniferous trees include cedar. Examples of waste wood include wood waste (lumber, boards, solid wood, laminated materials, plywood (veneer)), etc., generated during the demolition of wooden houses. Wood pieces can be used as is, but dried wood can also be used.

[0015] <Cut pieces of grass> In the present invention, cut pieces of 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 limitations on the type, and for example, cut pieces of grass family plants can be used as the main raw material. Specific examples include rice, wheat, and barley, and parts that can be used include stems (grass), branches, leaves, and rice husks. Cut pieces of grass can be used as they are, but dried pieces can also be used. There are also no particular limitations on the equipment used to cut plants, and examples include a plant shredder, a refiner, and a wood chipper. Furthermore, "cut pieces of plants" can sometimes be used as they are if they do not interfere with the reaction. For example, this is the case with leaves or rice husks.

[0016] <Iron Nitrate> Iron nitrate is in a crystalline state, such as iron nitrate hexahydrate (Fe(NO ３ ) ２ ・6H ２ O) or iron nitrate nonahydrate (Fe(NO ３ ) ３ ・9H ２ There is no particular limitation on the amount of iron nitrate added, but it is preferable to use iron nitrate (Fe(NO)) in an amount of hydrogen peroxide. ３ ) ２ The amount of iron nitrate added is preferably 0.2% by weight or more and 8.4% by weight or less. If the amount is 0.2% by weight or more, the reaction proceeds sufficiently, and if the amount is 8.4% by weight or less, no problems arise in terms of reactivity, including side reactions. From the above viewpoints, the amount of iron nitrate added is more preferably 0.2% by weight or more and 2% by weight or less.

[0017] <Hydrogen peroxide solution> There are no particular limitations on the concentration of hydrogen peroxide solution, but it is preferable to use 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 the 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, from the viewpoint of efficient production of iron fulvate, it is even more desirable for the concentration of hydrogen peroxide solution to be 25% by weight or more and 35% by weight or less.

[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, it is easy to control the reaction. More preferably, it is 40°C or higher and 50°C or lower. This is because the reaction state is stable and the reaction rate is fast. (Reaction time) It is preferably 12 hours or higher and 48 hours or lower. If it is 12 hours or higher, the reaction proceeds sufficiently, while if it is 48 hours or lower, the reaction proceeds sufficiently and high productivity is maintained. (Reaction pressure) There are no particular restrictions, but the reaction pressure is not important as long as the vessel is made of a non-humic material, temperature controllable, and capable of stirring, but for stable reaction, it is preferable to use a pressure close to normal pressure. (Order of addition) 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 for producing iron fulvic acid 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 be used, and techniques such as precipitation, filtration, dialysis, ultrafiltration, and gel filtration can be used. In the examples of the present invention, a simple filtration method using filter paper was used. Note that the insoluble matter contains cellulose and the like, and can be used for other purposes.

[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.) do not have a single chemical structure; rather, they are a collective term for a group of substances whose molecular structures vary depending on the humification process and raw materials. Therefore, no official method has yet been established for identifying and quantifying fulvic acid. In this invention, fulvic acid is defined as fulvic acid soluble in alkaline and acidic solutions in humic substances. The fulvic acid measurement method involved confirming the presence and measuring the content of fulvic acid using the following procedure. (a) Extraction of Alkali-Soluble Fraction: Sodium hydroxide solution was added to 100 mL of the measurement sample (iron fulvic acid extract) to a concentration of 0.1 M sodium hydroxide, extracting the alkali-soluble fraction, and filtering the supernatant. (b) Fractionation of Fulvic Acid: The supernatant was acidified with hydrochloric acid, and the resulting precipitate was filtered off, leaving a solution known as a fulvic acid solution. (c) Measurement of Three-Dimensional Fluorescence Spectrum: Three-dimensional excitation-fluorescence spectra were measured for the fulvic acid solution. The excitation wavelength (Ex) was measured between 200 and 500 nm, and the fluorescence wavelength (Em) was measured between 210 and 550 nm to obtain a three-dimensional excitation-fluorescence spectrum. Standardization was performed using Danto fulvic acid (distributed by the Japanese Humic Substances Society) as a standard substance, and the amount of fulvic acid contained in the fulvic acid solution was measured as a quantitative value, and the amount of fulvic acid in 100 mL of the measurement sample (iron fulvic acid extract) was calculated.

[0022] (Measurement of Iron Amount in Iron Fulvic Acid) The amount of iron in the iron fulvic acid extract was measured by eluting an iron complex using an anion exchange resin column and then subjecting it to ICP emission spectrometry.

[0023] Example 1 300 mL of 30% hydrogen peroxide solution was placed in a 2 L four-neck flask, and 50 g of cedar stump wood chips (particle size 1 mm) were added little by little while stirring with a mechanical stirrer. After adding the wood chips, iron (III) nitrate nonahydrate (Fe(NO ３ ) ３ ・9H ２ To the mixture, 1.8 g (0.6 wt %) of iron (III) nitrate nonahydrate (Fe(NO)) was added while paying attention to foaming and heat generation, and the mixture was allowed to react at 45° C. for 24 hours. Since unreacted hydrogen peroxide remained, iron (III) nitrate nonahydrate (Fe(NO)) was added. ３ ) ３ ・9H ２0) was added, and unreacted hydrogen peroxide was reacted. After that, insoluble matter in the solution after the reaction was removed by suction filtration, and 300 mL of iron fulvic acid extract was obtained. The concentration of fulvic acid in the iron fulvic acid extract was 3.2 mg / mL (equivalent to Danto fulvic acid). Iron in the iron fulvic acid extract was measured by eluting the iron complex using an anion exchange resin column, and the amount of iron was measured by ICP atomic emission spectrometry, confirming that iron fulvic acid had been produced.

[0024] Comparative Example 1 Iron (II) sulfate heptahydrate (FeSO ４ ・7H ２ 300 mL of fulvic acid iron extract was obtained in the same manner as in Example 1, except that 1.8 g of iron fulvic acid extract 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 extracts obtained in Example 1 and Comparative Example 1 250 times with tap water was applied to the komatsuna seedlings four times every five days starting seven 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 application of the iron fulvic acid extract of Example 1 with the 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 the iron fulvic acid extract using iron nitrate rather than iron sulfate.

[0027] Example 2 The same procedure as in Example 1 was repeated, except that 50 g of bark chips (manufactured by Ozaki Rinsan Kogyo 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 as in Example 1 was carried out, 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).

[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 can produce iron fulvic acid stably in a very simple manner in a short 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 wood from forests, contributing to forest development and the revitalization of mountain villages. Furthermore, revitalizing forestry allows people to return to satoyama (village forests) and helps maintain a rich natural balance, making it an industrially valuable technology.

Claims

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, followed by the sequential addition of iron nitrate, and allowing the mixture to react.

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. A method for producing iron fulvate according to any one of claims 1 to 3, characterized in that iron nitrate is used in an amount of 0.2% by weight to 8.4% by weight relative to the hydrogen peroxide solution.

6. A 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 to 100°C for 12 hours to 48 hours.

7. A method for producing an iron fulvic acid extract according to any one of claims 1 to 3, characterized in that insoluble matter is removed from the reaction solution of iron fulvic acid.

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