AMORPHOUS CARBON-METAL Iron COMPOSITE AND METHOD FOR PRODUCING SAME

Abstract

Provided is an amorphous carbon-metallic iron composite which is safe and easy to handle, maintains activity for a long period of time, and is capable of sufficiently reducing organic halogen compounds contained in soil or underground water. An amorphous carbon-metallic iron composite which contains amorphous carbon and an iron compound that contains at least an alpha-iron phase, and wherein: the content of carbon in the amorphous carbon-metallic iron composite is 45-75% by weight (inclusive); the total of the content of an alpha iron phase and the content of an austenite (gamma iron) phase in the amorphous carbon-metallic iron composite is 7.5% by weight or more and 55% by weight or less.

Description

Technical Field

[0001] The present invention relates to an amorphous carbon - metallic iron complex for decomposing organic halogen compounds contained in soil or groundwater to purify the soil or groundwater, and a method for purifying soil or groundwater. Background Art

[0002] Aliphatic organic halogen compounds such as trichloroethylene and tetrachloroethylene are widely used for cleaning in semiconductor factories and degreasing of metals used in metal processing.

[0003] In addition, exhaust gas, fly ash, and bottom ash generated from waste incinerators that incinerate municipal waste and industrial waste contain trace amounts of aromatic organic halogen compounds, dioxin - like substances, which are extremely toxic to humans. Dioxin - like substances are a general term for compounds in which hydrogen in dibenzo - p - dioxin, dibenzofuran, etc. is substituted by chlorine. Exhaust gas and fly ash will stay around the waste incinerator, resulting in dioxin - like substances remaining in the soil in the surrounding area.

[0004] Furthermore, PCB (polychlorinated biphenyl) is chemically stable, thermally stable, and has excellent electrical insulation properties. It was mostly used as insulating oil for transformers and capacitors, plasticizers, and heat media, but its manufacture and use have been prohibited due to its harmfulness. However, an effective treatment method for PCB used in the past has not been established, and most of it has been stored without treatment.

[0005] Organic halogen compounds such as aliphatic organic halogen compounds and aromatic organic halogen compounds are difficult to decompose and are carcinogenic substances or substances with strong toxicity. Therefore, pollution caused by organic halogen compounds in soil or groundwater has become a serious environmental problem.

[0006] That is, when the aforementioned organic halogen compounds are discharged, since the organic halogen compounds are difficult to decompose, they accumulate in the discharged soil and become contaminated with organic halogen compounds. Also, groundwater is contaminated with organic halogen compounds. Furthermore, groundwater will also spread to the surrounding areas outside the contaminated soil. Therefore, pollution caused by organic halogen compounds in a wide area has become a problem.

[0007] The soil contaminated with organic halogen compounds cannot be reused / redeveloped. Therefore, various technical means have been proposed as methods for purifying soil or groundwater contaminated with organic halogen compounds. However, since organic halogen compounds are difficult to decompose and a large amount of soil or groundwater needs to be treated, an efficient and economical purification technology has not been fully established.

[0008] As a method for purifying soil contaminated with organic halogen compounds, the following are known: a method of performing a purification treatment using various catalysts, a method of sucking and removing by utilizing the volatility of the organic halogen compound, a thermal decomposition method of excavating the soil and rendering it harmless by heat treatment, a method using microorganisms, and the like. Further, as a method for purifying groundwater contaminated with organic halogen compounds, the following are known: a method of pumping out the contaminated groundwater to the outside of the soil to render it harmless, a method of removing the organic halogen compound by pumping out the groundwater, and the like.

[0009] Recently, PFAS such as PFOS and PFOA have become the subject of regulation in various countries. PFAS is a general term for organic fluorine compounds, which are chemically stable substances that are difficult to decompose naturally and have a high persistence, and thus purification treatment technologies are required.

[0010] Among the technical means proposed as a method for purifying soil, groundwater, or wastewater contaminated with organic halogen compounds, there has been proposed a technical means of mixing and bringing into contact a purification agent using iron-based particles with soil, groundwater, or wastewater contaminated with an organic halogen compound to render it harmless (Patent Documents 1 to 9).

[0011] 〔Prior Art Documents〕

[0012] 〔Patent Documents〕

[0013] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-161263

[0014] Patent Document 2: Japanese Patent Application Laid-Open No. 2003-105313

[0015] Patent Document 3: Japanese Patent Application Laid-Open No. 2003-136051

[0016] Patent Document 4: Japanese Patent Application Laid-Open No. 2005-21882

[0017] Patent Document 5: Japanese Patent Application Laid-Open No. 2006-326561

[0018] Patent Document 6: Japanese Patent Application Laid-Open No. 2010-194450

[0019] Patent Document 7: Japanese Patent Application Laid-Open No. 2010-194451

[0020] Patent Document 8: Japanese Patent Application Laid-Open No. 2011-26524

[0021] Patent Document 9: Japanese Patent Application Laid-Open No. 2011-46985 Summary of the Invention

[0022] 〔Problems to be Solved by the Invention〕

[0023] What is most urgently needed at present is a purifying agent that can maintain its activity for a long time and can sufficiently reduce the organohalogen compounds contained in soil or groundwater, but such a purifying agent has not been obtained yet.

[0024] That is, Patent Document 1 mentioned above discloses iron powder for decomposing organohalogen compounds in which a metal selected from nickel, copper, cobalt, and molybdenum is attached to the surface and the surface other than the attached metal is covered with an iron oxide film. However, the iron powder used is iron powder made from millscale or iron powder obtained by water atomization of molten steel. Considering the specific surface area of the iron powder described, it is considered that the particle size of the iron powder is relatively large, and it is hard to say that it can sufficiently reduce organohalogen compounds.

[0025] Also, Patent Document 2 mentioned above discloses a detoxifying agent for organohalogen compounds composed of graphite and Fe-Ni, with a graphite content of 1 to 20% by weight and a Ni content of 0.1 to 15% by weight. However, it is considered that the particle size is relatively large, and it is hard to say that it can sufficiently reduce organohalogen compounds.

[0026] Also, Patent Document 3 mentioned above discloses metal powder for decomposing organohalogen compounds composed of iron particles with nickel attached, in which the phase with iron as the main component is the base metal phase and the phase with nickel as the main component is the attached metal phase. However, the particle size is as large as 1 to 500 μm, and it is hard to say that it can sufficiently reduce organohalogen compounds.

[0027] Also, Patent Document 4 mentioned above discloses a purification treatment using iron composite particle powder composed of α-Fe and magnetite in soil or groundwater contaminated with organohalogen compounds. However, there is still room for improvement in sufficiently decomposing organohalogen compounds over a long period of time.

[0028] Also, Patent Document 5 mentioned above discloses iron-based powder for purification in which Ni fine particles with an average particle size of 1 to 50 nm are attached to the surface of iron powder with iron as the main component. However, the average particle size of the iron-based particles is as large as 65 μm, and it is hard to say that it can sufficiently reduce organohalogen compounds.

[0029] Also, Patent Document 6 mentioned above discloses a purification method for organohalides in which iron powder and nickel sulfate and / or nickel chloride of less than 0.1% by weight relative to the iron powder are mixed in soil, wastewater, or groundwater contaminated with organohalides. Patent Document 7 mentioned above discloses a purification method for organohalides in which partial alloy powder having a partial alloy phase of iron and nickel inside and / or on the surface of iron powder and nickel sulfate and / or nickel chloride of less than 0.1% by weight relative to the partial alloy powder are mixed in soil, wastewater, or groundwater contaminated with organohalides. However, the particle sizes of the above-mentioned iron powder and partial alloy powder are relatively large, and it is hard to say that they can sufficiently reduce organohalogen compounds with a small addition amount.

[0030] Patent Document 8 describes an organic halogen compound decomposing material consisting of iron powder whose surface is coated with a metal nobler than iron such as nickel. However, the iron powder has a large particle size and it is difficult to say that a small amount of addition can sufficiently reduce the organic halogen compound.

[0031] Furthermore, the aforementioned Patent Document 9 describes an organic halide decomposition treatment agent consisting of iron powder obtained by pulverizing iron powder and a water-soluble nickel aqueous solution, or vigorously stirring the iron powder to precipitate nickel on the surface, and further partially alloying the nickel with iron. However, the iron powder has a large particle size, and it is difficult to say that the organic halogen compounds can be sufficiently reduced by a small amount of addition.

[0032] The object of the present invention is to provide an amorphous carbon-metal iron complex which is safe, easy to handle, can maintain activity for a long time, and can sufficiently reduce the organic halogen compounds contained in soil or groundwater, and a method for producing the same, and a method for purifying soil or groundwater using the amorphous carbon-metal iron complex.

[0033] [Methods for solving the problem]

[0034] The above-mentioned technical problems can be achieved by the following present invention.

[0035] That is, the present invention is an amorphous carbon-metal iron composite, which contains amorphous carbon and an iron compound containing at least an α iron phase, characterized in that the carbon content in the amorphous carbon-metal iron composite is not less than 45 weight % and not more than 75 weight %, and the total content of the α iron phase and the austenite (γ iron) phase in the amorphous carbon-metal iron composite is not less than 7.5 weight % and not more than 55 weight % (Invention 1).

[0036] The present invention is the amorphous carbon-metal iron composite of the present invention 1, characterized in that the BET specific surface area of ​​the amorphous carbon-metal iron composite is 0.5 m 2 / g above 80m 2 / g or less (Present invention 2).

[0037] The present invention is the amorphous carbon-metallic iron composite according to Invention 1 or Invention 2, characterized in that the crystal size of the α iron is not less than 40 nm and not more than 140 nm (Invention 3).

[0038] The present invention is the amorphous carbon-metal iron composite according to the first or second invention, wherein the bulk density (Japanese: かさ density) of the amorphous carbon-metal iron composite is 0.9 g / cm 3 Above 1.3g / cm 3 The following (Present Invention 4).

[0039] Furthermore, the present invention is a method for purifying soil or groundwater, characterized in that: for soil contaminated with organohalogen compounds or groundwater contaminated with organohalogen compounds, the amorphous carbon-iron metal complex described in the present invention 1 or the present invention 2 is used for purification treatment (the present invention 5).

[0040] Furthermore, the present invention is a medicament for insolubilizing heavy metals contained in soil or groundwater, which uses the amorphous carbon-iron metal complex described in the present invention 1 or the present invention 2 as an active ingredient (the present invention 6).

[0041] Furthermore, the present invention is a method for manufacturing the amorphous carbon-iron metal complex described in the present invention 1 or the present invention 2, characterized by including: a precursor manufacturing step of manufacturing a precursor embedding an iron raw material by softening a carbon raw material by applying energy; and a heat treatment step of reducing at least a part of the iron raw material by heat-treating the aforementioned precursor (the present invention 7).

[0042] Furthermore, the present invention is a method for manufacturing a soil or groundwater purifying agent, characterized by including: a precursor manufacturing step of manufacturing a precursor embedding an iron raw material by softening a carbon raw material by applying energy; and a heat treatment step of reducing at least a part of the iron raw material by heat-treating the aforementioned precursor (the present invention 8).

[0043] 〔Advantages of the Invention〕

[0044] The amorphous carbon-iron metal complex of the present invention is safe, easy to handle, can maintain its activity for a long time, and can sufficiently reduce the organohalogen compounds contained in soil or groundwater, and is suitable as a purifying agent. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 shows the measurement results of the TCE decomposition rate using the amorphous carbon-iron metal complex of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0046] The constitution of the present invention will be described in detail as follows.

[0047] The amorphous carbon-iron metal complex of the present invention is an amorphous carbon-iron metal complex containing amorphous carbon and an iron compound containing at least an α-iron phase, and the carbon content is 45% by weight or more and 75% by weight or less. If the carbon content is less than 45% by weight, the iron compound is likely to be oxidized. On the other hand, if the carbon content exceeds 75% by weight, the activity as a purifying agent will be low.

[0048] ​Furthermore, in the amorphous carbon-iron metal composite of the present invention, the total content of the α-iron phase and the austenite (γ-iron) phase is 7.5 wt% or more. Preferably, it is 8.0 wt% or more. If the total content of the α-iron phase and the austenite (γ-iron) phase is less than 7.5 wt%, the activity as a purifying agent will decrease. On the other hand, the upper limit of the total content of the α-iron phase and the austenite (γ-iron) phase is 55 wt%.

[0049] In the amorphous carbon-iron metal composite of the present invention, the BET specific surface area is preferably 0.5 m 2 / g or more and 80 m 2 / g or less. More preferably, it is 1.0 m 2 / g or more and 75 m 2 / g or less. If the BET specific surface area is less than 0.5 m 2 / g, the contact points with the substance to be purified will decrease. On the other hand, if the BET specific surface area exceeds 80 m 2 / g, the iron compounds contained will be easily oxidized.

[0050] In the amorphous carbon-iron metal composite of the present invention, the crystal size of α-iron is preferably 140 nm or less. More preferably, it is 137 nm or less. The smaller the crystal size of α-iron, the better. Therefore, the lower limit is not particularly limited, but considering the industrial manufacturability, 40 nm or more is appropriate. On the other hand, if the crystal size of α-iron exceeds 140 nm, the activity as a purifying agent will decrease.

[0051] In the amorphous carbon-iron metal composite of the present invention, the apparent density is preferably 0.9 g / cm 3 or more and 1.3 g / cm 3 or less. More preferably, it is 0.95 g / cm 3 or more and 1.25 g / cm 3 or less. If the apparent density is less than 0.9 g / cm 3 , the composite of amorphous carbon and iron metal is not sufficient. On the other hand, if the apparent density exceeds 1.3 g / cm 3 , the contact points with the substance to be purified will decrease.

[0052] In the amorphous carbon-iron metal composite of the present invention, preferably, the 10% particle size (D10) is 7 μm or more and 50 μm or less, and the 50% particle size (D50) is 15 μm or more and 100 μm or less. If D10 is less than 7 μm and / or D50 is less than 15 μm, dust is likely to fly during processing. On the other hand, if D10 exceeds 50 μm and / or D50 exceeds 100 μm, the contact points with the substance to be purified will decrease.

[0053] Next, a method for manufacturing the amorphous carbon-metal iron composite of the present invention will be described. The manufacturing process of the amorphous carbon-metal iron composite of the present invention includes: a precursor manufacturing process of manufacturing a precursor embedding an iron raw material by softening a carbon raw material by imparting energy; and a heat treatment process of reducing at least a part of the iron raw material by heat-treating the aforementioned precursor. Optionally, a coating process of providing a coating layer on the aforementioned precursor may be added. The coating process may be carried out between the precursor manufacturing process and the heat treatment process, or may be carried out after the heat treatment process.

[0054] <Precursor manufacturing process>

[0055] Regarding the carbon raw material in the present invention, as long as it is softened by applying heat energy or mechanical energy, partially thermally decomposed by heating at 400 °C or higher in an inert environment, and at least 70% by weight remains in the form of amorphous carbon after heat treatment, it is not particularly limited, but a solid compound containing hydrocarbons is preferred.

[0056] Regarding such a carbon raw material, examples include: raw materials derived from petroleum and coal, and raw materials derived from resins and synthetic resins. Petroleum coke obtained by heating heavy oil such as distillation residue to about 300 °C to 700 °C and performing thermal decomposition / polycondensation is preferred. Petroleum coke includes fluidized coke and delayed coke, and delayed coke includes green coke and calcined coke (calcined petroleum coke). Regarding the carbon raw material in the present invention, a raw material having a volatile content of 8% or more measured according to JIS M 8812 is preferred.

[0057] The iron raw material in the present invention is not particularly limited, but a substance that at least shows an iron-containing compound phase in the X-ray diffraction pattern is preferred. Regarding iron-containing compounds, examples include: metallic iron such as ferrite (α-Fe) and austenite (γ-Fe), iron oxides such as magnetite (Fe3O4), maghemite (γ-Fe2O3), hematite (α-Fe2O3), and wüstite (FeO), iron hydroxides such as goethite (α-FeOOH), and iron oxalate (FeC2O4), iron nitrate (Fe(NO3)2), iron chloride (FeCl2), etc. Magnetite, hematite, or goethite is further preferred.

[0058] Hereinafter, a method for manufacturing a precursor by mechanical energy using coal coke powder having a volatile content of about 13% as a carbon raw material and hematite powder as an iron raw material will be specifically described, but the amorphous carbon-metal iron composite of the present invention is not limited to the following manufacturing method.

[0059] The D50 of the coal coke powder used as the carbon raw material in the precursor manufacturing process is preferably 1 μm or more and 30 μm or less, more preferably 3 μm or more and 25 μm or less. If the D50 of the coal coke powder is less than 1 μm, it is not preferred because the compounding treatment becomes difficult. Also, if the D50 of the coal coke powder exceeds 30 μm, it is not preferred because the carbon content in each particle of the amorphous carbon-metal iron composite is likely to deviate.

[0060] The size of the hematite powder used as the iron raw material in the precursor manufacturing process is smaller than that of the coal coke powder used as the carbon raw material. The D50 of the hematite powder is preferably 0.1 μm or more and 10 μm or less, more preferably 0.5 μm or more and 5 μm or less. If the D50 of the hematite powder is less than 0.1 μm, it is not preferred because the compounding treatment becomes difficult. Also, if the D50 of the hematite powder exceeds 10 μm, it is not preferred because the iron content in each particle of the amorphous carbon-metal iron composite is likely to deviate.

[0061] The BET specific surface area of the hematite powder used as the iron raw material in the precursor manufacturing process is preferably 500 m 2 / g or less, more preferably 300 m 2 / g or less, and further preferably 150 m 2 / g or less. If the BET specific surface area of the hematite powder exceeds 500 m 2 / g, it is less preferred because the compounding treatment becomes difficult. The lower limit of the BET specific surface area of the hematite powder is about 1 m 2 / g.

[0062] The manufacturing method of the precursor is preferably a compounding treatment that imparts mechanical energy to the mixed powder of the carbon raw material and the iron raw material. Particularly preferred is a method of imparting mechanical energy while causing the powder to flow and performing mixing / dispersion. Since the flow of the powder causes shear, compression, collision, friction, etc., the carbon raw material and the iron raw material can be efficiently compounded.

[0063] Regarding the device that can impart mechanical energy such as the above shear, compression, collision, and friction to the powder, in addition to, for example, a roller press, a kneader, and a mixing granulator, there are also particle compounding devices such as Hybridization System (manufactured by Nara Machinery Co., Ltd.), Mechanofusion (manufactured by Hosokawa Micron Corporation), Nobilta (manufactured by Hosokawa Micron Corporation), and COMPOSI (manufactured by Nippon Coke & Engineering Co., Ltd.).

[0064] In the precursor manufacturing process, when treating the mixed powder of carbon raw material and iron raw material, the mixing ratio of the carbon raw material to the iron raw material is preferably 1:0.25 to 1.3 by weight. As long as the content ratio of the carbon raw material to the iron raw material is 1:0.5 to 1.25 by weight, regardless of the input amount and order of the raw materials in the compounding process. Therefore, in the compounding process, all the raw materials can be compounded at one time, or the remaining raw materials can be additionally added and compounded during or after compounding a part of the raw materials. The additionally added raw material can be any one of only the carbon raw material, only the iron raw material, and the mixed powder of the carbon raw material and the iron raw material.

[0065] The temperature of the powder in the process of imparting mechanical energy is preferably controlled to be 60°C or higher and less than 400°C. More preferably, it is 80°C or higher and less than 300°C, and particularly preferably, it is 100°C or higher and less than 250°C. At a temperature lower than 60°C, the carbon raw material does not soften and compounding becomes difficult, so it is less preferred. If it becomes a high temperature of 400°C or higher, there is a risk of fire or the like, so it is less preferred.

[0066] In the precursor manufacturing process, it is preferably compressed and compounded in such a way that the loose bulk density of the precursor becomes 1.2 times or more of the raw material powder or the raw material mixed powder. More preferably, it is 1.5 times or more, further preferably, it is 1.75 times or more, and particularly preferably, it is 2 times or more. If the loose bulk density of the precursor is less than 1.2 times of the raw material powder or the raw material mixed powder, the compounding is insufficient, so it is not preferred. The upper limit is about 5 times.

[0067] <Heat treatment process>

[0068] The method of heat treatment is not particularly limited as long as at least a part of the iron raw material in the aforementioned precursor can be reduced. Examples include: a method of performing heat treatment in a reducing environment such as hydrogen, a method of causing a reduction reaction by thermally decomposing at least a part of the raw material in an inert environment or a non-oxidizing environment, etc. The heat treatment conditions also vary depending on the type and mixing ratio of the raw materials used, but it is preferably set the maximum temperature reached to be 400°C or higher and 1600°C or lower, and the holding time at the maximum temperature reached to be 10 hours or less.

[0069] <Coating process>

[0070] A coating layer can also be provided on the precursor or the amorphous carbon-iron metal composite. Through the coating layer, oxidation of the iron metal can be prevented, and the storage stability and safety can be further improved. The material and method of the coating layer are not particularly limited. The coating process can be carried out between the precursor manufacturing process and the heat treatment process, or after the heat treatment process. Examples include: a method of compounding the carbon raw material and the iron raw material in the precursor manufacturing process, and then additionally adding the carbon raw material of the coated part and performing heat treatment.

[0071] Next, a purification treatment method for purifying soil contaminated with organohalogen compounds or groundwater contaminated with organohalogen compounds using the amorphous carbon-iron metal composite of the present invention as a purifying agent will be described.

[0072] For the purification treatment of soil contaminated with organohalogen compounds or groundwater contaminated with organohalogen compounds, it is generally preferred to use an in-situ decomposition method in which the contained contaminants are directly decomposed underground.

[0073] In the in-situ decomposition method, the following methods are adopted: a method of directly infiltrating or introducing the purifying agent underground using a gas such as high-pressure air or nitrogen or water as a medium; or a method of stirring and mixing the purifying agent with the contaminated soil using an excavation stirring mixer. Since the amorphous carbon-iron metal composite of the present invention is in powder form, it can be directly used or used in the form of an amorphous carbon-iron metal composite dispersion liquid dispersed in water.

[0074] As the concentration of the amorphous carbon-iron metal composite (solid component concentration) when the amorphous carbon-iron metal composite of the present invention is dispersed in water to form an amorphous carbon-iron metal composite dispersion liquid, it is preferably 0.01 to 25% by weight.

[0075] The addition amount of the amorphous carbon-iron metal composite (solid component) can be appropriately selected according to the degree of contamination of the organohalogen compounds in the soil or groundwater. However, when the contaminated soil is the object, generally, relative to 100 parts by weight of the soil, it is preferably 0.01 to 10 parts by weight, and more preferably 0.05 to 5 parts by weight. When it is less than 0.01 part by weight, the object effect of the present invention cannot be fully obtained. When it exceeds 10 parts by weight, the purification effect will be improved but it is not economical. Also, when the contaminated groundwater is the object, relative to 100 parts by weight of the groundwater, it is preferably added 0.01 to 80 parts by weight, and more preferably 0.05 to 50 parts by weight.

[0076] <Function>

[0077] The important point in the present invention is that the amorphous carbon-iron metal composite of the present invention can maintain its activity for a long time and sufficiently reduce the organohalogen compounds contained in the soil or groundwater.

[0078] The reason for being able to maintain its activity for a long time and sufficiently reduce the organohalogen compounds contained in the soil or groundwater is not yet clear, but the inventors of this case speculate as follows.

[0079] That is, in the amorphous carbon - metallic iron composite of the present invention and the method for purifying soil or groundwater using the same, the amorphous carbon is combined with metallic iron, thereby suppressing the rapid oxidation of metallic iron when it comes into contact with soil or water. The metallic iron with high activity as a purifying agent can maintain a low oxidation state. It is considered that the low - oxidation - state metallic iron mostly exists in soil or water, which is related to the sufficient reduction of organohalogen compounds. Also, it is considered that as the contact time with soil or water becomes longer, the amorphous carbon - metallic iron composite will deform and new active surfaces will appear, thereby maintaining the activity for a long time.

[0080] As described above, by combining amorphous carbon with metallic iron, the deterioration caused by the oxidation of metallic iron can be suppressed. In the amorphous carbon - metallic iron composite of the present invention, the amount of metallic iron exposed on the surface is small, and the metallic iron particles are firmly in close contact with the amorphous carbon. Therefore, gases and liquids are not easily intruded into the interior. Thus, even in an oxidative environment such as air or water, the oxidation reaction is suppressed to a minimum, and by disposing amorphous carbon between the metallic iron particles, the ignition caused by the runaway of oxidation heat can also be suppressed. As a result, the amorphous carbon - metallic iron composite of the present invention does not belong to dangerous substances and can be easily handled.

[0081] 〔Examples〕

[0082] The representative embodiments of the present invention are as follows.

[0083] <Measurement and evaluation methods>

[0084] (a) Measurement of 10% particle size D10 and 50% particle size D50

[0085] Measurement was carried out using a laser diffraction scattering particle size distribution measuring device “LMS - 2000e” (manufactured by Malvern).

[0086] (b) Measurement of specific surface area

[0087] Measurement was carried out using a specific surface area measuring device “Multisorb 16” (manufactured by Quantachrome) by the BET method.

[0088] (c) Measurement of apparent density

[0089] After gently putting the sample into a container with a spoon to form a mountain shape, without applying vibration, the protruding part was scraped off with a spatula, the weight of the contents of the container was measured, and the apparent density was calculated by dividing the weight by the volume of the container.

[0090] (d) Measurement of carbon content

[0091] Measurement was carried out using a carbon / sulfur analyzer “EMIA - 920V2” (manufactured by Horiba).

[0092] (e) Measurement of the content and crystal size of the crystalline phase

[0093] Measurement was carried out using an X-ray diffractometer “D8 ADVANCE” (manufactured by Bruker AXS), and the content and crystal size of the crystalline phase in the sample were calculated by Rietveld analysis.

[0094] (f) Evaluation of the purification treatment of organic halogen compounds in simulated groundwater and wastewater

[0095] (Preparation of calibration curve: Quantification of organic halogen compounds)

[0096] The concentration of organic halogen compounds was determined by preparing a calibration curve in advance according to the following procedure, and the concentration was calculated based on the obtained calibration curve.

[0097] Trichloroethylene (TCE: C2HCl3): Molecular weight 131.39

[0098] Special grade reagent (99.5%), density (20 °C) 1.461 - 1.469 g / mL

[0099] Prepare trichloroethylene in three volumes of 1.0 μL, 2.0 μL, and 3.5 μL. Add 40 mL of ion-exchanged water to a 100 mL brown vial. Then, inject each volume of trichloroethylene, immediately cover it with a rubber stopper lined with fluororesin, and firmly cover it with an aluminum seal from above. After leaving the vial standing at 30 °C for 20 minutes, draw 0.5 mL of the headspace gas with a syringe and measure trichloroethylene using “SRI8610C” (manufactured by SRI). Consider trichloroethylene as not completely decomposed and find the relationship between the added amount and the peak area. The column used at this time is a capillary column Ultra ALLOY-624: Frontier (manufactured by Laboratories, liquid phase: cyanopropylphenylmethyl polysiloxane). Use He gas (25 mL / min) as the carrier gas. After maintaining at 50 °C for 1 minute, raise the temperature to 120 °C at a rate of 10 °C / min and analyze the gas.

[0100] (Manufacture of amorphous carbon - iron metal composite dispersion)

[0101] First, mix 100 g of amorphous carbon - iron metal composite powder and 300 g of ion-exchanged water for 1 minute using a pot-type tester. Then, subject the mixture to a pulverization and mixing treatment for 60 minutes using a vertical batch-type wet bead mill (manufactured by AIMEX, effective volume 800 mL, grinding medium 2 mmφ glass beads) to prepare an amorphous carbon - iron metal composite dispersion containing 25 wt% (solid component concentration) of amorphous carbon - iron metal composite particles.

[0102] <Preparation of a sample for the determination of organic halogen compounds>

[0103] Adjust so that a 100 mL brown vial contains 0.528 g of an amorphous carbon - iron metal complex dispersion and 39.6 mL of ion - exchanged water. Then, inject 1.3 μL of trichloroethylene, immediately cap it with a rubber stopper lined with fluororesin, firmly cover it with an aluminum seal from above, and start allowing the reaction to stand.

[0104] <Evaluation method for the decomposition reaction of organic halogen compounds>

[0105] Allow the aforementioned vial to stand at 30 °C. After a specified reaction time, draw 0.5 mL of gas from the headspace in the vial with a syringe and measure the concentration of trichloroethylene (TCE) using the aforementioned "SRI8610C" (manufactured by SRI). Evaluate those with a TCE concentration of less than 0.01 mg / L after 240 hours (10 days) after the start of the reaction as ○, those with a TCE concentration of less than 0.01 mg / L after 300 hours (12.5 days) after the start of the reaction as △, and those with a TCE concentration of 0.01 mg / L or more after 300 hours (12.5 days) after the start of the reaction as ×.

[0106] (g) Evaluation of the purification treatment of per - and polyfluoroalkyl substances (PFAS) in simulated contaminated water

[0107] <Manufacture of an amorphous carbon - iron metal complex dispersion>

[0108] Place 25 g of amorphous carbon - iron metal complex powder, 75 g of ion - exchanged water, and 180 g of glass beads with a diameter of 2 mm in a 210 mL mayonnaise bottle. Use a test - type disperser (coating shaker) manufactured by Toyo Seiki Co., Ltd. to shake it for 3 hours, then remove the beads through a 1 - mm sieve to prepare an amorphous carbon - iron metal complex dispersion containing 25 wt% of amorphous carbon - iron metal complex particles.

[0109] <Preparation of a sample for the determination of organic fluorine compounds using an amorphous carbon - iron metal complex powder>

[0110] Place 2.4 g of amorphous carbon - iron metal complex powder and 105.6 mL of ion - exchanged water in a 250 mL polypropylene container. Then, inject 12 mL of a 1 mg / L aqueous solution of PFOA, PFOS, and PFHxS, cover the lid, shake and mix the whole, and start allowing the reaction to stand.

[0111] <Preparation of a sample for the determination of organic fluorine compounds using an amorphous carbon - iron metal complex dispersion>

[0112] Place 9.6 g of an amorphous carbon-metal iron complex dispersion and 99.8 mL of ion-exchanged water in a 250 mL polypropylene container. Then, inject 12 mL of a 1 mg / L aqueous solution of PFOA, PFOS, and PFHxS, cover the container with a lid, shake and mix the whole, and then start the static reaction.

[0113] <Preparation of a test sample for the determination of organofluorine compounds without an amorphous carbon-metal iron complex>

[0114] Place 108 mL of ion-exchanged water in a 250 mL polypropylene container. Then, inject 12 mL of a 1 mg / L aqueous solution of PFOA, PFOS, and PFHxS, cover the container with a lid, shake and mix the whole, and then start the static reaction.

[0115] <Evaluation method for the removal reaction of organofluorine compounds>

[0116] Let the aforementioned polypropylene container stand at room temperature, and measure the filtrate after a specified reaction time by LC-MS / MS.

[0117] <Manufacture of an amorphous carbon-metal iron complex>

[0118] <Amorphous carbon-metal iron complex 1>

[0119] Weigh 10.4 kg of coal tar powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mix them. The bulk density of the mixed powder is 0.462 g / cm 3 . Composite the mixed powder by mechanochemical treatment with shear force and compressive force applied, and then add 5.2 kg of the above-mentioned coal tar powder for additional treatment to obtain precursor 1. The D50 of precursor 1 is 53.02 μm, and the bulk density is 0.951 g / cm 3 , and the bulk density of precursor 1 is 2.059 times that of the mixed powder.

[0120] Next, heat-treat precursor 1 in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours to obtain amorphous carbon-metal iron complex 1. The BET specific surface area of amorphous carbon-metal iron complex 1 is 29.6 m 2 / g, the carbon content is 64.4 wt%, the bulk density is 1.110 g / cm 3 , the content of α-iron phase + γ-iron phase is 24.6 wt%, and the crystal size of α-iron is 104.3 nm. Also, D10 of amorphous carbon-metal iron complex 1 is 23.5 μm, and D50 is 49.8 μm.

[0121] <Amorphous carbon-metal iron complex 2>

[0122] Weigh 10.4 kg of coal tar powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mix them. The loose bulk density of the mixed powder is 0.459 g / cm 3 . Composite process the mixed powder by mechanical chemical treatment with shear force and compressive force applied, and then add 5.2 kg of the above-mentioned coal tar powder for additional treatment to obtain Precursor 2. The D50 of Precursor 2 is 52.27 μm, and the loose bulk density is 0.945 g / cm 3 , and the loose bulk density of Precursor 2 is 2.059 times that of the mixed powder's loose bulk density.

[0123] Next, heat-treat Precursor 2 in a nitrogen environment at a setting of holding at 800 °C for 5 hours to obtain Amorphous Carbon-Metal Iron Composite 2. The BET specific surface area of Amorphous Carbon-Metal Iron Composite 2 is 28.5 m 2 / g, the carbon content is 62.5 wt%, the loose bulk density is 1.125 g / cm 3 , and the content of α-iron phase + γ-iron phase is 18.3 wt%, and the crystal size of α-iron is 127.1 nm.

[0124] <Amorphous Carbon-Metal Iron Composite 3>

[0125] Weigh 10.4 kg of coal tar powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mix them. The loose bulk density of the mixed powder is 0.463 g / cm 3 . Composite process the mixed powder by mechanical chemical treatment with shear force and compressive force applied, and then add 5.2 kg of the above-mentioned coal tar powder for additional treatment to obtain Precursor 3. The D50 of Precursor 3 is 37.90 μm, and the loose bulk density is 0.927 g / cm 3 , and the loose bulk density of Precursor 3 is 2.003 times that of the mixed powder's loose bulk density.

[0126] Next, heat-treat Precursor 3 in a nitrogen environment at a setting of holding at 800 °C for 5 hours, and control the cooling rate after heat treatment at about 20 °C / hour to obtain Amorphous Carbon-Metal Iron Composite 3. The BET specific surface area of Amorphous Carbon-Metal Iron Composite 3 is 49.5 m 2 / g, the carbon content is 63.3 wt%, the loose bulk density is 1.002 g / cm 3 , and the content of α-iron phase + γ-iron phase is 36.7 wt%, and the crystal size of α-iron is 133.5 nm.

[0127] <Amorphous Carbon-Metal Iron Composite 4>

[0128] Weigh 1.2 kg of coal tar powder with a D50 of 18.5 μm and 1.2 kg of hematite powder with a BET specific surface area of 103 m 2 / g, and gently mix them. The apparent density of the mixed powder is 0.461 g / cm 3 . Composite the mixed powder by mechanochemical treatment with shear force and compressive force applied, and then add 0.6 kg of the above coal tar powder for additional treatment to obtain precursor 4. The D50 of precursor 4 is 42.04 μm, and the apparent density is 0.962 g / cm 3 , and the apparent density of precursor 4 is 2.084 times that of the mixed powder.

[0129] Next, heat-treat precursor 4 in a nitrogen environment at a setting of holding at 800 °C for 5 hours to obtain amorphous carbon-metal iron composite 4. The BET specific surface area of amorphous carbon-metal iron composite 4 is 5.6 m 2 / g, the carbon content is 66.8 wt%, the apparent density is 1.118 g / cm 3 , and the content of α-iron phase + γ-iron phase is 21.4 wt%, and the crystal size of α-iron is 51.0 nm.

[0130] <Amorphous carbon-metal iron composite 5>

[0131] Heat-treat precursor 4 in a nitrogen environment at a setting of holding at 850 °C for 5 hours to obtain amorphous carbon-metal iron composite 5. The BET specific surface area of amorphous carbon-metal iron composite 5 is 13.9 m 2 / g, the carbon content is 68.5 wt%, the apparent density is 1.111 g / cm 3 , and the content of α-iron phase + γ-iron phase is 31.5 wt%, and the crystal size of α-iron is 55.0 nm.

[0132] <Amorphous carbon-metal iron composite 6>

[0133] Weigh 1.8 kg of coal tar powder with a D50 of 19.0 μm and 1.2 kg of hematite powder with a BET specific surface area of 107 m 2 / g, and gently mix them. The apparent density of the mixed powder is 0.480 g / cm 3 . Composite the mixed powder by mechanochemical treatment with shear force and compressive force applied to obtain precursor 6. The D50 of precursor 6 is 40.22 μm, and the apparent density is 0.984 g / cm 3 , and the apparent density of precursor 6 is 2.049 times that of the mixed powder.

[0134] Next, the precursor 6 was heat-treated under a nitrogen atmosphere according to the setting of maintaining at 750 °C for 5 hours to obtain an amorphous carbon-metal iron composite 6. The BET specific surface area of the amorphous carbon-metal iron composite 6 was 13.9 m 2 / g, the carbon content was 64.1 wt%, the apparent density was 1.109 g / cm 3 , and the content of the α-iron phase + γ-iron phase was 23.7 wt%, and the crystal size of α-iron was 49.9 nm.

[0135] <Amorphous carbon-metal iron composite 7>

[0136] The precursor 6 was heat-treated under a nitrogen atmosphere according to the setting of maintaining at 800 °C for 5 hours to obtain an amorphous carbon-metal iron composite 7. The BET specific surface area of the amorphous carbon-metal iron composite 7 was 13.5 m 2 / g, the carbon content was 65.1 wt%, the apparent density was 1.117 g / cm 3 , and the content of the α-iron phase + γ-iron phase was 29.8 wt%, and the crystal size of α-iron was 51.8 nm.

[0137] <Amorphous carbon-metal iron composite 8>

[0138] 1.8 kg of coal tar powder with a D50 of 18.2 μm and 1.2 kg of hematite powder with a BET specific surface area of 107 m 2 / g were weighed and gently mixed. The apparent density of the mixed powder was 0.479 g / cm 3 . The mixed powder was subjected to a mechanochemical treatment with shear force and compressive force to be compounded, thereby obtaining a precursor 8. The D50 of the precursor 8 was 47.73 μm, and the apparent density was 1.017 g / cm 3 , and the apparent density of the precursor 8 was 2.122 times that of the mixed powder.

[0139] Next, the precursor 8 was heat-treated under a nitrogen atmosphere according to the setting of maintaining at 750 °C for 5 hours to obtain an amorphous carbon-metal iron composite 8. The BET specific surface area of the amorphous carbon-metal iron composite 8 was 7.4 m 2 / g, the carbon content was 64.7 wt%, the apparent density was 1.124 g / cm 3 , and the content of the α-iron phase + γ-iron phase was 18.9 wt%, and the crystal size of α-iron was 55.6 nm.

[0140] <Amorphous carbon-metal iron composite 9>

[0141] The precursor 8 was heat-treated under a nitrogen atmosphere according to the setting of maintaining at 800 °C for 5 hours to obtain an amorphous carbon-metal iron composite 9. The BET specific surface area of the amorphous carbon-metal iron composite 9 was 20.9 m2 / g, the carbon content is 60.9 wt%, and the apparent density is 1.126 g / cm 3 , the content of α-iron phase + γ-iron phase is 17.0 wt%, and the crystal size of α-iron is 62.3 nm.

[0142] <Amorphous carbon-metal iron composite 10>

[0143] Weigh 1.2 kg of coal tar powder with a D50 of 18.5 μm and 1.2 kg of goethite powder with a BET specific surface area of 6.9 m 2 / g, and gently mix them. The apparent density of the mixed powder is 0.405 g / cm 3 . The mixed powder is subjected to a mechanochemical treatment with shear force and compression force to be compounded, and then 0.6 kg of the above-mentioned coal tar powder is added for treatment, thereby obtaining precursor 10. The D50 of precursor 10 is 60.65 μm, and the apparent density is 0.994 g / cm 3 , and the apparent density of precursor 10 is 2.454 times that of the mixed powder.

[0144] Next, precursor 10 is heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours to obtain amorphous carbon-metal iron composite 10. The BET specific surface area of amorphous carbon-metal iron composite 10 is 8.2 m 2 / g, the carbon content is 66.3 wt%, and the apparent density is 1.139 g / cm 3 , the content of α-iron phase + γ-iron phase is 28.7 wt%, and the crystal size of α-iron is 115.5 nm.

[0145] <Amorphous carbon-metal iron composite 11>

[0146] Precursor 10 is heat-treated in a nitrogen atmosphere at a setting of holding at 850 °C for 5 hours to obtain amorphous carbon-metal iron composite 11. The BET specific surface area of amorphous carbon-metal iron composite 11 is 2.0 m 2 / g, the carbon content is 64.5 wt%, and the apparent density is 1.171 g / cm 3 , the content of α-iron phase + γ-iron phase is 24.3 wt%, and the crystal size of α-iron is 112.6 nm.

[0147] <Amorphous carbon-metal iron composite 12>

[0148] Precursor 10 is heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours, and the cooling rate after heat treatment is controlled at about 20 °C / hour, thereby obtaining amorphous carbon-metal iron composite 12. The BET specific surface area of amorphous carbon-metal iron composite 12 is 2.9 m 2 / g, the carbon content is 63.9 wt%, and the apparent density is 1.157 g / cm 3 , the content of α-iron phase + γ-iron phase is 32.9 wt%, and the crystal size of α-iron is 98.1 nm.

[0149] <Amorphous carbon - metallic iron composite 13>

[0150] Weigh 1.3 kg of coal tar powder with a D50 of 18.5 μm and 1.5 kg of hematite powder with a BET specific surface area of 103 m 2 / g, and gently mix them. The apparent density of the mixed powder is 0.477 g / cm 3 . The mixed powder is subjected to a mechanochemical treatment with shear force and compressive force for composite treatment, and then 0.4 kg of the above-mentioned coal tar powder is added for treatment, thus obtaining precursor 13. The D50 of precursor 13 is 47.48 μm, and the apparent density is 1.052 g / cm 3 , and the apparent density of precursor 13 is 2.207 times that of the mixed powder.

[0151] Then, precursor 13 is heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours to obtain amorphous carbon - metallic iron composite 13. The BET specific surface area of amorphous carbon - metallic iron composite 13 is 18.0 m 2 / g, the carbon content is 57.9 wt%, and the apparent density is 1.134 g / cm 3 , the content of α-iron phase + γ-iron phase is 36.3 wt%, and the crystal size of α-iron is 56.1 nm.

[0152] <Amorphous carbon - metallic iron composite 14>

[0153] Weigh 1.5 kg of coal tar powder with a D50 of 18.5 μm and 1.5 kg of hematite powder with a BET specific surface area of 103 m 2 / g, and gently mix them. The apparent density of the mixed powder is 0.479 g / cm 3 . The mixed powder is subjected to a mechanochemical treatment with shear force and compressive force for composite treatment, thus obtaining precursor 14. The D50 of precursor 14 is 61.20 μm, and the apparent density is 1.058 g / cm 3 , and the apparent density of precursor 14 is 2.209 times that of the mixed powder.

[0154] Then, precursor 14 is heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours to obtain amorphous carbon - metallic iron composite 14. The BET specific surface area of amorphous carbon - metallic iron composite 14 is 31.4 m 2 / g, the carbon content is 51.0 wt%, and the loose bulk density is 1.221 g / cm 3 , the content of α-iron phase + γ-iron phase is 19.2 wt%, and the crystal size of α-iron is 77.4 nm.

[0155] <Amorphous carbon-metal iron composite 15>

[0156] Weigh 10.4 kg of coal char powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mix them. The loose bulk density of the mixed powder is 0.459 g / cm 3 . The mixed powder is subjected to a mechanochemical treatment with shear force and compressive force to be compounded, and then 5.2 kg of the above-mentioned coal char powder is added for treatment, thereby obtaining precursor 15. The D50 of precursor 15 is 52.27 μm, and the loose bulk density is 0.945 g / cm 3 , and the loose bulk density of precursor 15 is 2.059 times that of the mixed powder.

[0157] Then, precursor 15 is heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours to obtain amorphous carbon-metal iron composite 15. The BET specific surface area of amorphous carbon-metal iron composite 15 is 27.0 m 2 / g, the carbon content is 61.9 wt%, and the loose bulk density is 1.122 g / cm 3 , the content of α-iron phase + γ-iron phase is 14.0 wt%, and the crystal size of α-iron is 135.7 nm.

[0158] <Amorphous carbon-metal iron composite 16>

[0159] Weigh 10.4 kg of coal char powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mix them. The loose bulk density of the mixed powder is 0.460 g / cm 3 . The mixed powder is subjected to a mechanochemical treatment with shear force and compressive force to be compounded, and then 5.2 kg of the above-mentioned coal char powder is added for treatment, thereby obtaining precursor 16. The D50 of precursor 16 is 36.81 μm, and the loose bulk density is 0.911 g / cm 3 , and the loose bulk density of precursor 16 is 1.980 times that of the mixed powder.

[0160] Next, the precursor 16 was heat-treated under a nitrogen atmosphere at a setting of maintaining at 800 °C for 5 hours, and the cooling rate after the heat treatment was controlled at about 20 °C / hour, thereby obtaining an amorphous carbon-metal iron composite 16. The BET specific surface area of the amorphous carbon-metal iron composite 16 was 49.3 m 2 / g, the carbon content was 64.4 wt%, the apparent density was 1.018 g / cm 3 , the content of α-iron phase + γ-iron phase was 35.6 wt%, and the crystal size of α-iron was 137.0 nm.

[0161] <Amorphous carbon-metal iron composite 17>

[0162] Weighed 10.4 kg of coal tar powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mixed them. The apparent density of the mixed powder was 0.463 g / cm 3 . The mixed powder was subjected to a mechanochemical treatment with shear force and compressive force for compounding, and then 5.2 kg of the above-mentioned coal tar powder was additionally treated, thereby obtaining a precursor 17. The D50 of the precursor 17 was 37.90 μm, and the apparent density was 0.927 g / cm 3 , and the apparent density of the precursor 17 was 2.003 times that of the mixed powder.

[0163] Next, the precursor 17 was heat-treated under a nitrogen atmosphere at a setting of maintaining at 800 °C for 5 hours, and the cooling rate after the heat treatment was controlled at about 20 °C / hour, thereby obtaining an amorphous carbon-metal iron composite 17. The BET specific surface area of the amorphous carbon-metal iron composite 17 was 48.3 m 2 / g, the carbon content was 63.4 wt%, the apparent density was 1.019 g / cm 3 , the content of α-iron phase + γ-iron phase was 36.6 wt%, and the crystal size of α-iron was 136.5 nm.

[0164] <Amorphous carbon-metal iron composite 18>

[0165] Weighed 1.8 kg of coal tar powder with a D50 of 19.0 μm and 0.6 kg of hematite powder with a BET specific surface area of 107 m 2 / g, and gently mixed them. The apparent density of the mixed powder was 0.501 g / cm 3 . The mixed powder was subjected to a mechanochemical treatment with shear force and compressive force for compounding, and then 0.6 kg of the above-mentioned hematite powder was additionally treated, thereby obtaining a precursor 18. The D50 of the precursor 18 was 43.54 μm, and the apparent density was 0.995 g / cm 3, the apparent density of the precursor 18 is 1.986 times that of the blended powder.

[0166] Next, the precursor 18 was heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours, thereby obtaining an amorphous carbon-metal iron composite 18. The BET specific surface area of the amorphous carbon-metal iron composite 18 is 5.0 m 2 / g, the carbon content is 63.1 wt%, the apparent density is 1.145 g / cm 3 , the content of α-iron phase + γ-iron phase is 10.1 wt%, and the crystal size of α-iron is 60.1 nm.

[0167] <Amorphous carbon-metal iron composite 19>

[0168] Weighed 10.4 kg of coal char powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mixed them. The apparent density of the blended powder is 0.460 g / cm 3 . The blended powder was subjected to a mechanochemical treatment with shear force and compressive force for compounding, and then 5.2 kg of the above-mentioned coal char powder was added for treatment, thereby obtaining a precursor 19. The D50 of the precursor 19 is 36.36 μm, and the apparent density is 0.929 g / cm 3 , the apparent density of the precursor 19 is 2.018 times that of the blended powder.

[0169] Next, the precursor 19 was heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours, and the cooling rate after heat treatment was controlled at about 20 °C / hour, thereby obtaining an amorphous carbon-metal iron composite 19. The BET specific surface area of the amorphous carbon-metal iron composite 19 is 44.2 m 2 / g, the carbon content is 64.4 wt%, the apparent density is 1.023 g / cm 3 , the content of α-iron phase + γ-iron phase is 35.6 wt%, and the crystal size of α-iron is 140.7 nm.

[0170] <Amorphous carbon-metal iron composite 20>

[0171] Weighed 10.4 kg of coal char powder with a D50 of 19.4 μm and 10.4 kg of hematite powder with a BET specific surface area of 105 m 2 / g, and gently mixed them. The apparent density of the blended powder is 0.462 g / cm 3。The composite treatment of the mixed powder was carried out by mechanochemical treatment with shear force and compressive force applied, and then 5.2 kg of the above-mentioned coal coke powder was additionally treated to obtain precursor 20. The D50 of precursor 20 was 40.15 μm, and the tapped density was 0.939 g / cm 3 , and the tapped density of precursor 20 was 2.032 times that of the mixed powder.

[0172] Next, precursor 20 was heat-treated in a nitrogen atmosphere at a setting of holding at 800 °C for 5 hours to obtain an amorphous carbon-metal iron composite 20. The BET specific surface area of the amorphous carbon-metal iron composite 20 was 31.3 m 2 / g, the carbon content was 61.7 wt%, the tapped density was 1.106 g / cm 3 , and the content of α-iron phase + γ-iron phase was 18.4 wt%, and the crystal size of α-iron was 145.8 nm.

[0173] <Amorphous carbon-metal iron composite 21>

[0174] Precursor 18 was heat-treated in a nitrogen atmosphere at a setting of holding at 750 °C for 5 hours to obtain an amorphous carbon-metal iron composite 21. The BET specific surface area of the amorphous carbon-metal iron composite 21 was 1.9 m 2 / g, the carbon content was 60.6 wt%, the tapped density was 1.178 g / cm 3 , and the content of α-iron phase + γ-iron phase was 4.8 wt%, and the crystal size of α-iron was 69.2 nm. Since the content of α-iron phase + γ-iron phase in the amorphous carbon-metal iron composite 21 was less than 7.5 wt%, it did not belong to the amorphous carbon-metal iron composite of the present invention.

[0175] <Amorphous carbon-metal iron composite 22>

[0176] 1.5 kg of coal coke powder with a D50 of 18.5 μm and 1.2 kg of hematite powder with a BET specific surface area of 103 m 2 / g were weighed and gently mixed. The tapped density of the mixed powder was 0.465 g / cm 3 . After the composite treatment of 0.3 kg of the above-mentioned coal coke powder by mechanochemical treatment with shear force and compressive force applied, the aforementioned mixed powder was added and further composite-treated by mechanochemical treatment to obtain precursor 22. The D50 of precursor 22 was 48.47 μm, and the tapped density was 0.977 g / cm 3 , and the tapped density of precursor 22 was 2.100 times that of the mixed powder.

[0177] Next, the precursor 22 was heat-treated in a nitrogen atmosphere under the condition of maintaining at 750 °C for 5 hours, thereby obtaining the amorphous carbon-metal iron composite 22. The BET specific surface area of the amorphous carbon-metal iron composite 22 was 8.2 m 2 / g, the carbon content was 59.7 wt%, the apparent density was 1.184 g / cm 3 , and the content of α-iron phase + γ-iron phase was 4.9 wt%, and the crystal size of α-iron was 85.8 nm. Since the content of α-iron phase + γ-iron phase in the amorphous carbon-metal iron composite 22 was less than 7.5 wt%, it did not belong to the amorphous carbon-metal iron composite of the present invention.

[0178] Table 1 shows the manufacturing conditions and physical property values of each precursor. Also, Table 2 shows the manufacturing conditions and physical property values of each amorphous carbon-metal iron composite.

[0179] [Table 1]

[0180]

[0181] [Table 2]

[0182]

[0183] [Amorphous carbon-metal iron composite 23]

[0184] 16.0 kg of amorphous carbon-metal iron composite 1, 8.2 kg of amorphous carbon-metal iron composite 16, 4.5 kg of amorphous carbon-metal iron composite 21, and 15.5 kg of amorphous carbon-metal iron composite 22 were mixed, thereby obtaining the amorphous carbon-metal iron composite 23. The BET specific surface area of the amorphous carbon-metal iron composite 23 was 37.7 m 2 / g, the carbon content was 64.2 wt%, the apparent density was 1.053 g / cm 3 , and the content of α-iron phase + γ-iron phase was 29.0 wt%, and the crystal size of α-iron was 126.8 nm.

[0185] [Amorphous carbon-metal iron composite 24]

[0186] 10.0 kg of amorphous carbon-metal iron composite 2, 11.0 kg of amorphous carbon-metal iron composite 3, 0.9 kg of amorphous carbon-metal iron composite 15, 7.0 kg of amorphous carbon-metal iron composite 17, 0.8 kg of amorphous carbon-metal iron composite 21, and 3.0 kg of amorphous carbon-metal iron composite 22 were mixed, thereby obtaining the amorphous carbon-metal iron composite 24. The BET specific surface area of the amorphous carbon-metal iron composite 24 was 40.0 m 2 / g, the carbon content was 62.9 wt%, the apparent density was 1.051 g / cm3 The content of α-iron phase + γ-iron phase is 29.4 wt%, and the crystal size of α-iron is 126.0 nm.

[0187] In the amorphous carbon-iron metal composite, 1, 3, 4, 6-10, 15, 16, 21-24 are used to adjust the amorphous carbon-iron metal composite dispersion liquid, and the TCE decomposition rate in the dispersion liquid is measured. Table 3 and Figure 1 show the TCE decomposition evaluation and the decomposition rate of TCE.

[0188] [Table 3]

[0189]

[0190] As Figure 1 shown, in Example 4 using the amorphous carbon-iron metal composite 6 and Example 8 using the amorphous carbon-iron metal composite 10, the decomposition rate of TCE was still maintained at a high level after 100 hours, and TCE continued to decompose after 200 hours. At the 355-hour time point, the TCE concentration was 0.0043 mg / L.

[0191] On the other hand, in Comparative Example 1 using the amorphous carbon-iron metal composite 21, the decomposition rate of TCE decreased after 100 hours. Furthermore, at the 355-hour time point, the TCE concentration was 0.0411 mg / L, which was about 10 times the concentration compared with Examples 4 and 8.

[0192] The TCE decomposition rate was measured directly using the powder of the amorphous carbon-iron metal composite 24. The result was 0.451 mg / L at 287 hours after the start of the reaction, 0.333 mg / L at 792 hours (33 days), and 0.0059 mg / L at 1536 hours (64 days). The activity continued for a long time and finally reached less than 0.01 mg / L.

[0193] Using the amorphous carbon-iron metal composite 13, the removal rate of organic fluorine compounds in the amorphous carbon-iron metal composite powder and the amorphous carbon-iron metal composite dispersion liquid was measured. In the purification treatment of organic fluorine compounds using the amorphous carbon-iron metal composite powder, the concentrations of PFOS, PFOA, and PFHxS after 1 hour were 0.5 μg / L, 2.4 μg / L, and 12.2 μg / L, respectively. In the purification treatment of organic fluorine compounds without the amorphous carbon-iron metal composite powder, the concentrations of PFOS, PFOA, and PFHxS after 1 hour were all 100 μg / L and there was no change at all.

[0194] Furthermore, in the purification treatment of the organic fluorine compound using the amorphous carbon-iron metal composite dispersion liquid, the concentrations of PFOS, PFOA, and PFHxS after 2 weeks were 0.008 μg / L, 0.23 μg / L, and 1.2 μg / L, respectively.

[0195] It was confirmed that when using the amorphous carbon-iron metal composite of the present invention, the concentration of the organic fluorine compound can be reduced.

[0196] 〔Industrial Applicability〕

[0197] The amorphous carbon-iron metal composite of the present invention is also suitable as an agent for insolubilizing heavy metals contained in soil or groundwater and a catalyst for catalytic hydrogenation reactions.

Claims

1. An amorphous carbon - iron metal complex, which comprises amorphous carbon and an iron compound containing at least an α - iron phase, and is characterized in that: The content of carbon in the aforementioned amorphous carbon-metal iron composite is 45% by weight or more and 75% by weight or less. The total content of the α-iron phase and the austenite (γ-iron) phase in the aforementioned amorphous carbon-metal iron composite is 7.5% by weight or more and 55% by weight or less.

2. The amorphous carbon - iron metal complex according to claim 1, characterized in that, The BET specific surface area of the aforementioned amorphous carbon-metal iron composite is 0.5 m 2 / g or more and 80 m 2 / g or less.

3. The amorphous carbon - iron metal complex according to claim 1 or 2, characterized in that, The crystal size of the aforementioned α-iron is 40 nm or more and 140 nm or less.

4. The amorphous carbon - iron metal complex according to claim 1 or 2, characterized in that, The apparent density of the aforementioned amorphous carbon-iron metal composite is 0.9 g / cm 3 or more and 1.3 g / cm 3 or less.

5. A method for purifying soil or groundwater, characterized in that, For soil contaminated with organic halogen compounds or groundwater contaminated with organic halogen compounds, the purification treatment is carried out using the amorphous carbon-metal iron composite according to claim 1 or 2.

6. A medicament for insolubilizing heavy metals contained in soil or groundwater, which uses the amorphous carbon - iron metal complex according to claim 1 or 2 as an active ingredient.

7. A method for manufacturing the amorphous carbon - iron metal complex according to claim 1 or 2, characterized in that Comprising: A precursor manufacturing step of manufacturing a precursor embedding an iron raw material by softening a carbon raw material by applying energy; And A heat treatment step of reducing at least a part of the iron raw material by heat-treating the aforementioned precursor.

8. A method for manufacturing a purifying agent for soil or groundwater, characterized in that Comprising: A precursor manufacturing step of manufacturing a precursor embedding an iron raw material by softening a carbon raw material by applying energy; And A heat treatment step of reducing at least a part of the iron raw material by heat-treating the aforementioned precursor.

Images