Method for manufacturing organic matter decomposition materials

Abstract

To provide an organic material decomposition material excellent in decomposability of an organic material and a method for manufacturing the same.SOLUTION: An organic decomposition material is an organic decomposition material containing porous charred material derived from biomass containing calcium carbonate and microorganisms. The organic matter decomposition material may further include iron powder or a binder. A method for producing organic matter decomposition material involves carbonizing biomass to prepare porous char, carbonating the porous char by contacting the porous char with carbon dioxide-containing gas, and adding microorganisms to the carbonated porous char.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One embodiment of the present invention relates to an organic matter decomposing material and a method for producing the same. For example, the present invention relates to an organic matter decomposing material capable of decomposing organic matter contained in various water areas, soil, exhaust gas or the like, and a method for producing the same.

Background Art

[0002] Porous materials containing microorganisms are known as materials capable of decomposing and / or adsorbing organic matter contained in various water areas such as rivers, lakes, marshes and the sea, soil, or exhaust gas. For example, Patent Documents 1 and 2 disclose materials in which microorganisms capable of decomposing organic matter are incorporated into a porous material having carbon as a basic skeleton.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] One embodiment of the present invention has an object to provide an organic matter decomposing material excellent in the ability to decompose organic matter in water, in soil, or in exhaust gas, and a method for producing the same.

[0005] One embodiment of the present invention has an object to provide a carbon dioxide storage system in which the above organic matter decomposing material is interposed.

Means for Solving the Problems

[0006] One embodiment of the present invention is an organic matter decomposing material. The organic matter decomposing material includes porous carbide derived from biomass containing calcium carbonate, and microorganisms.

[0007] One embodiment of the present invention is an organic decomposition material comprising a porous char derived from biomass containing calcium carbonate and microorganisms. The pH of the porous char may be in the range of 8 to 10.

[0008] One embodiment of the present invention is a method for producing an organic matter decomposition material. In this method, biomass is carbonized to prepare a porous carbonized material, the porous carbonized material is brought into contact with a carbon dioxide-containing gas to carbonate it, and microorganisms are added to the carbonated porous carbonized material.

[0009] One embodiment of the present invention is a method for producing an organic matter decomposition material. In this method, biomass is carbonized and prepared, microorganisms are added to the porous carbonized material, and the porous carbonized material to which the microorganisms have been added is brought into contact with a carbon dioxide-containing gas to carbonize the porous carbonized material. [Brief explanation of the drawing]

[0010] [Figure 1] A flowchart showing a method for producing an organic matter decomposition material according to one embodiment of the present invention. [Figure 2] A flowchart showing a method for producing an organic matter decomposition material according to one embodiment of the present invention. [Figure 3] A conceptual diagram showing a carbon dioxide storage system via an organic matter decomposition material according to one embodiment of the present invention. [Modes for carrying out the invention]

[0011] The embodiments of the present invention will be described below with reference to the drawings and other materials. However, the present invention can be implemented in various forms without departing from its spirit, and is not to be interpreted as being limited to the embodiments described below.

[0012] In this specification, the term "phosphorus" includes not only elemental phosphorus but also compounds containing phosphorus. Therefore, phosphorus also includes phosphoric acid. Here, the term "phosphoric acid" is used not only to mean phosphoric acid in the narrow sense, i.e., compounds represented by the chemical formula H3PO4, but also to refer to various phosphates, monohydrogen phosphates, and dihydrogen phosphates in addition to phosphoric acid (H3PO4). Therefore, for example, iron phosphate, unless otherwise specified, refers not only to iron phosphate but also to monohydrogen phosphate and dihydrogen phosphate. Furthermore, there are no restrictions on the valency of the metal contained in the phosphate; for example, the iron ion in iron phosphate may be divalent or trivalent.

[0013] <Embodiment 1> The following describes an organic matter decomposition material according to one embodiment of the present invention, a method for producing the same, and a method for decomposing organic matter contained in soil, water, and exhaust gas using the organic matter decomposition material.

[0014] 1. Composition of organic matter decomposition material The organic matter decomposition material includes porous carbonized material and microorganisms. The organic matter decomposition material may further contain additives. Examples of additives include microbial activators. The organic matter decomposition material may be in powder form or molded into pellet form or the like. When the organic matter decomposition material is molded into pellet form or the like, a binder may be added. Alternatively, the organic matter decomposition material may be molded by another method without adding a binder.

[0015] (1) Porous carbide The porous carbide is a carbide produced by heating and carbonizing an organic substance under low oxygen concentration conditions. Biomass is exemplified as the organic substance. Biomass refers to biologically derived substances and their metabolites, which are a type of organic substance. For example, materials derived from trees can be cited as biomass. Specific examples include plate-like or columnar wood, thinned wood, pruned waste wood, construction waste wood, powdered sawdust, and wood such as particle boards. There are no restrictions on the type of tree, and cedar, cypress, or bamboo may be used. Alternatively, agricultural wastes such as rice husks, bagasse, corn cobs and leaves, and agricultural by-products such as straw, wheat straw, and hay can also be cited as examples of biomass. Alternatively, plants that serve as raw materials for fibers such as hemp, flax, cotton, sisal, abaca, and coir can be cited. Alternatively, algae such as seaweed may be used. Alternatively, food residues, silage obtained from forage crops, and the like can be cited. As will be described later, by using biomass as a raw material for the porous carbide, a system for sequestering carbon dioxide in the atmosphere can be constructed.

[0016] The size and shape of the porous carbide are not particularly limited, but the average particle diameter of the porous carbide may be 1 μm or more and 50 mm or less, or 1 μm or more and 1 mm or less. By having an average particle diameter within this range, the porous carbide can be uniformly mixed with the additive in the mixing step described later.

[0017] Due to micrometer-order sized pores formed inside the porous carbide, the porous carbide has a large specific surface area. Specifically, the specific surface area of the porous carbide is 100 m 2 / g or more and 900 m 2 / g or less, 100 m 2 / g or more and 800 m 2 / g or less, or 150 m 2 / g or more and 400 m 2 / g or less. The specific surface area is measured using a gas adsorption method exemplified by the mercury intrusion porosimetry, BJH method, or HK method, and the like.

[0018] Porous carbide derived from biomass contains inorganic compounds such as oxides of alkali metals or alkaline earth metals, and in particular, calcium oxides, chlorides, hydroxides, sulfates, or nitrates (hereinafter referred to as calcium compounds) are contained at a relatively high content. As will be described later, in the production of the organic matter decomposing material, the porous carbide is treated with carbon dioxide (carbonation). Therefore, these calcium compounds react with carbon dioxide to produce calcium carbonate or calcium bicarbonate. For this reason, the organic matter decomposing material contains calcium carbonate or calcium bicarbonate at a relatively high concentration. The concentration of calcium can be measured by applying inductively coupled plasma optical emission spectrometry (ICP-OES) or inductively coupled plasma mass spectrometry (ICP-MS) to the organic matter decomposing material. In ICP-OES, argon plasma is used as an emission light source, and a nebulized solution sample is introduced into the plasma to disperse the spectrum unique to metals, and metal ions can be quantified from the measurement wavelength and emission intensity. ICP-MS is a method that uses argon plasma as an ion source, ionizes elements contained in a sample, and separates and detects ions based on their mass-to-charge ratio. Elements can be identified from the mass-to-charge ratio of the detected ions, and metal ions can be quantified by counting the detected ions. The content of each compound may be determined by calculation from the quantified content of metal ions.

[0019] (2) Microorganisms Microorganisms contribute to the decomposition of organic matter, and may be either aerobic microorganisms or anaerobic microorganisms. Examples of aerobic microorganisms include Pseudomonas bacteria, ammonia-oxidizing bacteria, and nitrite-oxidizing bacteria. Examples of anaerobic microorganisms include nitrate-reducing bacteria, iron-reducing bacteria, sulfate-reducing bacteria, acid-producing bacteria, acetic acid-producing bacteria, and methanogenic archaea. Microorganisms inhabit the large number of pores present in the porous carbide as their nests.

[0020] Porous charred materials obtained by carbonizing biomass are alkaline, for example, with a pH of around 10 to 13. However, alkaline porous charred materials are not a favorable growth environment for microorganisms, and in excessively alkaline environments, microorganisms become inactive. Therefore, it has been difficult to produce organic matter decomposition materials with excellent decomposition capabilities using biomass-derived porous charred materials and microorganisms. In this invention, porous charred materials are carbonated during the manufacturing process of the organic matter decomposition material. Carbonation converts alkali metals and alkaline earth metal salts (e.g., calcium hydroxide), which cause an alkaline environment, into carbonates, thereby changing the pH of the porous charred materials to a weakly alkaline environment of around 7 to 10. In other words, carbonated porous charred materials can provide an environment suitable for the growth and proliferation of microorganisms. As a result, microorganisms can maintain a highly active state, and this invention can provide an organic matter decomposition material that can maintain the high organic matter decomposition capacity provided by microorganisms over a long period of time.

[0021] If porous carbonized before adding microorganisms, the porous carbonized material becomes a weakly alkaline environment, which provides a suitable environment for the growth and proliferation of microorganisms. This allows for the provision of an organic matter decomposition material that fully utilizes the high organic matter decomposition capacity of the microorganisms.

[0022] When porous carbonized material and microorganisms are mixed before carbonization, the microorganisms may be damaged due to the alkaline environment of the porous carbonized material or the heat and atmospheric changes associated with the carbonization process. Therefore, by anticipating the decrease in viable cell count due to microbial damage and adding an amount of microorganisms to the porous carbonized material to compensate for the reduced viable cell count, or by adding microorganisms after the carbonization process, it is possible to provide an organic matter decomposition material with high microbial decomposition capacity.

[0023] Detailed manufacturing methods will be described in Embodiments 2 and 3.

[0024] (3) Microbial activating materials Examples of microbial activating materials include nutrients, iron that contributes to phosphorus adsorption and microbial growth, reducing agents, and electron acceptors. (3-1) Nutritional supplements Nutrients act as nutrients for microorganisms and include nitrogen compounds, phosphorus compounds, potassium compounds, sodium compounds, proteins, peptones, vitamins, minerals (Fe, Mn, Zn, Mg, etc.), sugars, organic acids, and iron phosphate. These contain elements or components essential for microbial growth. Examples of nitrogen compounds, phosphorus compounds, potassium compounds, and sodium compounds include sodium chloride, potassium chloride, sodium hydrogen phosphate, potassium hydrogen phosphate, ammonium chloride, ammonium nitrate, and iron phosphate. Examples of sources for these nutrients include compost, food fermentation residues, and yeast extracts. Examples of compost include manure collected from livestock such as cattle, pigs, and chickens, mixed with plant-based auxiliary materials such as sawdust, rice hulls, straw, and wood chips, and fermented. Sources of vitamins include extracts, such as concentrated meat extracts, plant extracts, or yeast extracts.

[0025] (3-2) Iron When an organic matter decomposition material is used to decompose organic matter and remove phosphorus from water simultaneously, including iron (zero-valent iron) allows for more effective phosphorus adsorption. In this case, the iron is adsorbed onto porous carbon as iron phosphate. Furthermore, iron also functions as a source of iron ions, which are electron acceptors for anaerobic microorganisms, thus promoting the decomposition of organic matter by these microorganisms. Therefore, the organic matter decomposition material may contain iron phosphate as a source of iron ions. Since iron phosphate also functions as a carrier for microorganisms, the organic matter decomposition material can be more efficiently enriched with microorganisms.

[0026] Iron may be present in the organic decomposition material as zero-valent iron powder, i.e., iron powder. The iron powder may contain trace amounts of other elements. Other elements include carbon, oxygen, sulfur, phosphorus, manganese, silicon, vanadium, copper, and titanium. Therefore, the purity of the iron powder may be 80.0% to 99.9% or 95.0% to 99.0%. Some of the iron in the iron powder may be oxidized and exist as iron oxide or iron hydroxide. At least some of the iron oxide exists as magnetite (Fe3O4). Other parts of the iron oxide may exist as wustite (FeO), or as hematite or maghemite (Fe2O3). The valency of the iron in the iron hydroxide may be monovalent, divalent, or a mixed valency of divalent and trivalent atoms.

[0027] There are no restrictions on the shape of the iron powder; for example, iron powder with an average circularity of 50 to 100 can be used. Here, average circularity is one of the parameters that represent the shape of each powder particle contained in the powder. It is obtained by analyzing images obtained by microscopic observation of the powder, determining the circularity of multiple powder particles, and averaging these values. For example, the value obtained by dividing the perimeter of the projection surface of each powder particle in the microscopic image by the perimeter of a circle with an area equal to the area of ​​the projection surface can be used as the circularity. Alternatively, the value obtained by dividing the area of ​​the projection surface by the area of ​​a circle inscribed in the projection surface may be adopted as the circularity. There are also no restrictions on the particle size of the iron powder; for example, iron powder in which 90% by mass of the iron powder particles have a particle size of 20 μm to 600 μm, or 20 μm to 250 μm, can be used.

[0028] (3-3) Reducing agent Reducing agents are used to maintain an appropriate oxidation-reduction potential on the surface and within the pores of porous carbon materials for the growth and proliferation of microorganisms, especially anaerobic microorganisms. Examples of reducing agents include sodium sulfide, sodium thioglycolate, cysteine, cysteine ​​hydrochloride, and ascorbic acid. When anaerobic microorganisms are used, reducing agents should be added so that the oxidation-reduction potential on the surface and within the pores of the porous carbon material is in the range of 100mV to -400mV. On the other hand, when aerobic microorganisms are used, the oxidation-reduction potential is adjusted to be in the range of 250mV to 400mV. In the latter case, it is not always necessary to add a reducing agent; the organic matter decomposition material should be kept in an environment that can come into contact with the atmosphere, and oxygen should function as the reducing agent.

[0029] (3-4) Electron acceptors Electron acceptors function as substances that maintain microbial respiration, especially in the case of anaerobic microorganisms. Examples of electron acceptors include metal oxides such as iron, aluminum, or tin, as well as nitrates or sulfates, with nitrate ions, iron ions, and sulfate ions acting as electron acceptors.

[0030] (4) Binder A binder, one of the optional components, can be used to efficiently mix and integrate porous carbonized material with microbial activating material during the production of the organic matter decomposition material described later, and to provide an easy-to-handle organic matter decomposition material by granulating the resulting mixture and molding it into various shapes. There are no restrictions on the type of binder, but organic binders and / or inorganic binders can be used. Examples of organic binders include polysaccharides such as molasses, waste molasses, starch, dextrin, corn starch, and rice bran; polyvinyl alcohol, copolymers of vinyl acetate and ethylene or their saponified products; pulp waste liquid; organic acids such as lignin sulfonates; carboxymethylcellulose, hydroxypropyl methylcellulose, sodium alginate, phenolic resin, and tar pitch. Among these, molasses is inexpensive, contains few harmful components, and has a large solid component, making it easy to mold the organic matter decomposition material. Organic binders can also be used as nutrients for the growth and proliferation of microorganisms. Sawdust can also be used as an organic binder. Examples of inorganic binders include cement, blast furnace slag powder, fly ash, gypsum (calcium sulfate), calcined gypsum obtained by heating and dehydrating gypsum, and sodium silicate.

[0031] 2.Composition ratio The composition ratios of porous carbides, microorganisms, and additives in the organic matter decomposition material described above can be adjusted as appropriate. For example, if the organic matter decomposition material contains a binder, the content of porous carbides in the organic matter decomposition material can be adjusted to within the range of 20% to 80% by mass, 40% to 80% by mass, or 60% to 80% by mass, and the content of the binder can also be 5% to 50% by mass, 5% to 30% by mass, or 5% to 20% by mass. If the organic matter decomposition material contains iron powder, the content of iron powder in the organic matter decomposition material can be adjusted to within the range of 5% to 35% by mass, 5% to 25% by mass, or 5% to 20% by mass. These compositions are adjusted by the input ratio in the manufacturing process.

[0032] <Embodiment 2> This embodiment describes the method for producing the organic matter decomposition material described in Embodiment 1. Configurations that are the same as or similar to those described in Embodiment 1 may be omitted from the description.

[0033] 1. Preparation of porous carbides An example of a method for producing organic matter decomposition material is shown in the flowchart of Figure 1. First, biomass is used as a starting material, and the biomass is carbonized to prepare porous carbonized material. Specifically, porous carbonized material can be prepared by heating the biomass in an inert gas atmosphere such as nitrogen gas or argon gas, an oxygen-free atmosphere, a low-oxygen atmosphere, a reducing atmosphere, or a reduced-pressure atmosphere using an internal combustion or external heating type carbonization furnace. The heating temperature in the preparation of porous carbonized material should be between 400°C and 1200°C, between 500°C and 1100°C, between 600°C and 1000°C, or between 600°C and 900°C. The heating time should be between 10 minutes and 10 days, or between 10 minutes and 5 hours.

[0034] The carbonization of biomass generates carbonized gas, and produces porous carbonized material with a complex mixture of pores of various shapes and sizes, resulting from a combination of pores inherent in the biomass structure and pores formed by the desorption of carbonized gas. The carbonized gas mainly contains flammable or reducing gases such as hydrogen, carbon monoxide, methane, propane, and alkanes such as butane. Since the carbonized gas is extracted at high temperatures (700°C to 1300°C), its thermal energy and flammability can be used as an energy source for power generation, hot water supply, and other applications.

[0035] 2. Carbonation Next, the porous carbide is carbonated. Specifically, the porous carbide is brought into contact with a carbon dioxide-containing gas. The carbon dioxide-containing gas may contain other gases in addition to carbon dioxide. Examples of other gases include air, nitrogen, oxygen, noble gases such as argon, or water (water vapor). The concentration of carbon dioxide in the carbon dioxide-containing gas can be adjusted as appropriate, and can be set appropriately from the range of 1% to 100% by volume, 1% to 50% by volume, or 1% to 20% by volume.

[0036] Examples of sources for carbon dioxide-containing gas include gas cylinders and tanks containing carbon dioxide. Alternatively, exhaust gas from facilities that emit large amounts of carbon dioxide (chemical plants, waste incineration plants, thermal power plants, and various other factories) or purified carbon dioxide obtained by dedusting, desulfurizing, or denitrifying exhaust gas may be used. Alternatively, carbon dioxide separated and recovered from exhaust gas using the amine process may be used. If facilities that emit large amounts of carbon dioxide are close to the manufacturing site of organic matter decomposition materials, these facilities can function as a source of carbon dioxide-containing gas, thereby reducing the cost of transporting carbon dioxide and preventing secondary emissions of carbon dioxide associated with transportation.

[0037] To efficiently carbonate alkali metal salts or alkaline earth metal salts contained in porous carbides, it is preferable that either the carbon dioxide-containing gas or the porous carbide contains water (water vapor). Alternatively, both the carbon dioxide-containing gas and the porous carbide may contain water (water vapor). The water content in the porous carbide is, for example, 10% by weight or more and 40% by weight or less. Alternatively, the relative humidity of the carbon dioxide-containing gas may be set to 20% to 95%, or 50% to 90%.

[0038] When water (water vapor) is present during carbonation, if the oxide contained in the porous carbide is calcium oxide, the calcium oxide reacts with water and rapidly changes to calcium hydroxide. Therefore, carbonation proceeds even at room temperature or near room temperature (for example, between 15°C and 35°C). Furthermore, calcium ions such as calcium hydroxide or calcium chloride in the solution present in the pores can also react with carbon dioxide. Unlike the reaction between solid salt and carbon dioxide, carbonation proceeds rapidly under mild conditions, and as a result, the energy required for carbonation can be reduced.

[0039] By carbonation, porous carbides containing calcium carbonate at a concentration of, for example, 1% to 10% by mass or 1% to 5% by mass can be obtained. Furthermore, peaks originating from calcium carbonate can be observed in the X-ray diffraction (XRD) spectrum of the porous carbide.

[0040] By carbonizing porous carbonized material, the pH, which was unsuitable for microbial growth (pH 10-13) before carbonization, becomes suitable for microbial growth (pH 7-10, or above pH 7 but below pH 10) after carbonization.

[0041] 3. Addition of microorganisms Microorganisms can be added to carbonated porous carbonized materials by various methods. Here, the addition of microorganisms to porous carbonized materials refers simply to adding them to the porous carbonized material, regardless of the activity state (inactive or active) of the microorganisms. When microorganisms are added to porous carbonized materials in an active state, it may also be expressed as "supporting the microorganisms on the porous carbonized material."

[0042] One method involves mixing powdered microorganisms with carbonated porous carbon. This method yields an organic matter decomposition material containing porous carbon and aerobic or anaerobic microorganisms added to the porous carbon.

[0043] Another method involves preparing a culture medium containing microorganisms and water in a container called a bioreactor, and immersing carbonated porous carbon in it. In this method, the microorganisms can be supplied directly as a powder or supported on a carrier such as sawdust, incinerator ash, or activated carbon. At this time, organic compounds may be added to the culture medium as nutrients to promote the growth and proliferation of aerobic microorganisms.

[0044] Alternatively, aerobic and / or anaerobic microorganisms may be added when adding the additives and binders described later. Specifically, porous carbonized material may be mixed with the binder and / or additives, and aerobic and / or anaerobic microorganisms may be added to this mixture. In this case, water may be added during mixing. Adding water prevents the generation of dust and allows for uniform mixing. In addition, instead of microorganisms or carriers on which microorganisms are supported, livestock manure such as that of cattle may be used as a source of microorganisms.

[0045] 4. Addition of additives In the method for producing this organic matter decomposition material, the above-mentioned additives are added. As shown in Figure 1, the additives can be added at any time after the preparation of the carbonized material. For example, the additives may be added before carbonation or after carbonation. Furthermore, the additives may be added before or after the addition of microorganisms.

[0046] 5. Addition of binder and granulation As an optional step, a binder may be added, and the organic matter decomposition material may be molded (granulated) into a specific shape using a granulator. Examples of granulators for granulation include compression granulators, extrusion granulators, roll granulators, blade granulators, melt granulators, or spray granulators. The timing of granulation can also be determined arbitrarily, and as shown in Figure 1, it may be performed after the preparation of the carbide, before carbonation, before the addition of microorganisms, or after the addition of microorganisms. For example, a mixture obtained by mixing porous carbide and a binder may be granulated, and microorganisms may be added by immersing the molded mixture in a culture medium containing aerobic microorganisms in a bioreactor. Since granulation is performed in the presence of a binder, the binder is added before granulation.

[0047] Granulation allows for the production of organic matter decomposition materials of any shape. There are no restrictions on the shape of the organic matter decomposition material; it can be spherical, ellipsoidal, cylindrical, elliptical, or polygonal (pellet shape). In the case of pellet shape, for example, the pellets are granulated so that their lengths are 1 mm to 20 mm, 3 mm to 15 mm, or 6 mm to 12 mm. If the cross-sectional shape is circular, the ratio of the height (thickness) to the diameter of the pellet should be between 0.5 and 5.0. Through the above process, organic matter decomposition materials of uniform shape can be produced.

[0048] Alternatively, a mixture of porous carbide, a binder, and iron powder may be granulated, and the molded mixture may be immersed in phosphorus-containing water. This process incorporates the phosphorus in the water into the mixture as iron phosphate. The mixture can then be immersed in a culture medium containing aerobic or anaerobic microorganisms to support them.

[0049] Although not shown in Figure 1, a drying step may be included as an optional step. The drying temperature and time are also appropriately selected depending on the amount of organic matter decomposition material and the amount of water contained. However, because microorganisms are present, the drying temperature is selected from a range such as 15°C to 40°C, 15°C to 35°C, or 15°C to 30°C. The drying time is also appropriately selected from a range such as 1 minute to 1 week, 1 hour to 3 days, or 3 hours to 1 day.

[0050] <Embodiment 3> In this embodiment, we will describe other methods for producing the organic matter decomposition material described in Embodiment 1. Configurations that are similar to or identical to those described in Embodiments 1 and 2 may be omitted from the description.

[0051] Figure 2 shows a flowchart of the method for producing the organic matter decomposition material according to this embodiment. As can be seen from Figure 2, one of the differences between this embodiment and other methods for producing the organic matter decomposition material and the method described in Embodiment 2 is that in the former, carbonation is performed after the addition of microorganisms.

[0052] As mentioned above, porous carbides before carbonation are alkaline. Therefore, some of the microorganisms added before carbonation may be inactivated. In addition, some of the microorganisms may be inactivated by the heat generated during carbonation. For this reason, in this embodiment, microorganisms may be added again after carbonation. Alternatively, the amount of microorganisms added may be increased compared to Embodiment 2.

[0053] <Embodiment 4> In this embodiment, an organic matter decomposition material is used to decompose organic matter Solution This section will discuss the following. Descriptions of configurations similar to or identical to those described in Embodiments 1 to 3 may be omitted.

[0054] As described above, in the manufacturing process of the organic matter decomposition material according to one embodiment of the present invention, the porous char is carbonated. Therefore, a weakly alkaline environment can be maintained on the surface and inside the pores of the porous char. Such a weakly alkaline environment is suitable for the growth and proliferation of microorganisms that contribute to the decomposition of organic matter. For this reason, the organic matter decomposition material can maintain its ability to decompose organic matter contained in soil, water, and exhaust gas for a long period of time, and functions as an effective purification material for purifying soil, water bodies, and exhaust gas.

[0055] 1. Soil purification This organic matter decomposition agent can be used to decompose organic matter in soil contaminated with various organic substances derived from oil components such as gasoline, kerosene, diesel fuel, and heavy oil, as well as animal carcasses, food residues, and natural plant materials such as wood and cotton. The organic matter decomposition agent may be directly applied to the contaminated soil, or it may be applied to or mixed with excavated contaminated soil. The porous carbon contained in the organic matter decomposition agent is relatively brittle and easily disintegrates during the soil remediation process, either physically or through water infiltration, resulting in the rapid diffusion of microorganisms into the soil. Furthermore, since liquid organic substances such as oil components are adsorbed by the porous carbon, it is also possible to reduce the amount of organic matter in the soil to a level where the microorganisms that have diffused into the soil can decompose it. Therefore, soil remediation can be performed with high efficiency.

[0056] When using aerobic microorganisms, land farming is performed as needed or air is continuously supplied to the soil to replenish oxygen, which acts as an electron donor. When using anaerobic microorganisms, purification by anaerobic microorganisms is possible by using organic matter decomposition materials that contain electron acceptors other than oxygen (e.g., iron or iron salts). Furthermore, since oxygen is not required as an electron acceptor, pollutants in the soil can be decomposed without the need for periodic soil replacement (land farming). This contributes to reducing the cost of soil purification.

[0057] 2. Water purification This organic matter decomposition material contains aerobic and / or anaerobic microorganisms supported on the surface and within the pores of porous carbon. Therefore, it can be used to decompose organic matter contained in domestic wastewater and other substances when used to purify water in various bodies of water such as rivers, lakes, and seas, as well as in water treatment plants. Water purification can be carried out in batch or continuous mode. Water purification is performed by bringing this organic matter decomposition material into contact with the contaminated water to be purified. To prevent the organic matter decomposition material from flowing into the body of water due to disintegration in water, the organic matter decomposition material should be filled into containers or bags made of a material that allows water to permeate but not the porous carbon after disintegration (e.g., mesh-like metal plate, fabric, etc.) and brought into contact with the water in the body of water. If iron and / or iron oxide are contained in the organic matter decomposition material, iron phosphate, which has low solubility in water, is produced by the reaction of iron oxide with phosphoric acid. This is adsorbed on the surface and within the pores of the porous carbon, so it is possible to simultaneously remove phosphorus (e.g., phosphates, etc.) from various bodies of water.

[0058] When water is treated using adsorbents that primarily consist of porous carbonized materials such as activated carbon, the pH of the purified water (treated water) often increases. This is thought to be because oxides of alkaline earth metals such as calcium contained in the porous carbonized material react with water to produce hydroxides. However, as mentioned above, in the manufacturing process of this organic matter decomposition material, the porous carbonized material undergoes carbonation by carbon dioxide, and as a result, the alkaline earth metals exist as weakly alkaline carbonates and / or bicarbonates (e.g., calcium carbonate). Therefore, the increase in pH of the treated water can be effectively suppressed, and by using this organic matter decomposition material for water quality improvement, pH adjustment of the treated water becomes unnecessary, and the treated water can be directly discharged into rivers, etc.

[0059] 3. Exhaust gas purification This organic matter decomposition material contains not only porous carbonized material but also microorganisms supported on its surface and within its pores. Therefore, it can adsorb various organic substances through the large number of pores present in the porous carbonized material. Furthermore, it can decompose not only volatile organic compounds such as toluene, xylene, ethyl acetate, and methanol present in exhaust gas, but also fluorine-containing organic compounds such as perfluorooctanoic acid and perfluorooctanesulfonic acid. Exhaust gas purification can be performed by bringing the air to be treated into contact with this organic matter decomposition material. In exhaust gas purification, since the organic matter decomposition material is constantly in contact with oxygen, it is preferable to use aerobic microorganisms.

[0060] 4. Carbon dioxide storage systems A carbon dioxide storage system can be constructed by manufacturing the organic matter decomposition material described in Embodiments 2 to 4 and using it to decompose organic matter. Specifically, in the manufacturing of the organic matter decomposition material according to one embodiment of the present invention, porous carbonized material obtained by carbonizing biomass is used as one of the raw materials. At this time, by using the carbonized gas obtained by carbonizing biomass as an energy source, it is possible to generate electricity or produce hot water (Figure 3, (1)).

[0061] The resulting porous carbide is treated with a gas containing carbon dioxide (Figure 3, (2)). As a result, alkali metal or alkaline earth metal oxides or salts contained in the porous carbide, typically calcium oxide or calcium hydroxide, react with carbon dioxide to obtain carbonated porous carbide containing calcium carbonate. Carbonation can be carried out under mild conditions of 15°C to 35°C, rather than at high temperatures of, for example, 700°C or higher, thus enabling low-cost carbonation. Microorganisms are added to the carbonated porous carbide. In addition, a binder for molding and microbial activating materials such as compost, reducing agents, or electron acceptors to promote microbial growth can be added (Figure 3, (3)).

[0062] The resulting organic matter decomposition material can be used not only to decompose contaminated soil, but also to decompose water in various bodies of water and organic matter contained in exhaust gases (Figure 3, (4)). The purified soil contributes to plant growth. That is, carbon dioxide from the atmosphere is fixed through photosynthesis by plants, providing not only food but also materials such as wood (Figure 3, (5)). The residues of food and materials can be reused as biomass.

[0063] As described above, by applying embodiments of the present invention, a series of cycles is established that include the production of porous carbonized material from biomass (1), its carbonation (2), the manufacture of organic matter decomposition material (3), the purification of soil, water, and exhaust gas (4), and the growth of plants and regeneration of biomass using the purified soil (5). In this cycle, atmospheric carbon dioxide fixed by plants is utilized as porous carbonized material constituting the organic matter decomposition material and is also stored in the ground in the form of carbon. Furthermore, in the carbonation process, a portion of the carbon dioxide is fixed as metal salts such as calcium carbonate. Therefore, this cycle is a system that reduces and stores atmospheric carbon dioxide in the ground, contributing to the reduction of atmospheric carbon dioxide.

[0064] The embodiments described above as examples of the present invention can be combined and implemented as appropriate, insofar as they do not contradict each other. Additions, deletions, or design modifications of components based on these embodiments, made by those skilled in the art, are also included within the scope of the present invention, as long as they retain the essence of the invention.

[0065] Any effects or benefits other than those brought about by the embodiments described above, if they are clear from the description herein or easily predictable to those skilled in the art, are naturally understood to be brought about by the present invention.

Claims

1. By carbonizing biomass, porous carbonized material is prepared. The porous carbide is brought into contact with a carbon dioxide-containing gas at a temperature range of 15°C to 35°C to carbonize the porous carbide. This includes adding microorganisms to the carbonated porous carbonized material. A method for producing an organic matter decomposition material, wherein the carbon dioxide-containing gas contains water with a relative humidity of 20% to 95%, and the components other than water contain carbon dioxide in an amount of 1% to 100% by volume.

2. By carbonizing biomass, porous carbonized material is prepared. Microorganisms are added to the porous carbon material. The process involves carbonizing the porous carbonized material to which the microorganisms have been added by bringing it into contact with a carbon dioxide-containing gas at a temperature range of 15°C to 35°C. A method for producing an organic matter decomposition material, wherein the carbon dioxide-containing gas contains water with a relative humidity of 20% to 95%, and the components other than water contain carbon dioxide in an amount of 1% to 100% by volume.

3. The manufacturing method according to claim 1 or claim 2, wherein the water content of the porous carbide when the porous carbide is carbonated is 10% by weight or more and 40% by weight or less.

4. The manufacturing method according to claim 1, wherein the addition of the microorganism is carried out by mixing the carbonated porous carbon with compost, mixing the carbonated porous carbon with microbial powder, or immersing the carbonated porous carbon in a culture medium containing the microorganism.

5. The manufacturing method according to claim 1 or claim 2, further comprising mixing the carbonated porous carbide with iron powder.

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