Iron powder for odor elimination and deodorization

Abstract

The purpose of the present disclosure is to provide an iron powder for odor elimination and deodorization, the iron powder having an excellent odor elimination and deodorization effect against various substances. An iron powder for odor elimination and deodorization according to one aspect of the present disclosure contains iron as a main component and contains 0.5% by mass or more of oxygen.

Description

Iron powder for deodorization

[0001] The present disclosure relates to iron powder for deodorization.

[0002] Due to the growing awareness of hygiene, there is an increasing demand for antibacterial substances and deodorizing and deodorizing substances. In particular, because the presence or absence of antibacterial properties is difficult to perceive with the five senses, whereas odors are naturally perceived through the sense of smell, deodorizing and deodorizing substances are attracting more attention today.

[0003] Japanese Patent Application Publication No. 6-316401

[0004] Patent Document 1 describes a hydrogen sulfide absorbent made of finely pulverized iron powder. On the other hand, in everyday living spaces, for example, there are various targets for deodorization and deodorization other than hydrogen sulfide.

[0005] The present disclosure has been made in view of the above circumstances, and has an object to provide an iron powder for deodorization that has excellent deodorizing effects on various targets.

[0006] The iron powder for deodorization according to one embodiment of the present disclosure contains iron as a main component and 0.5 mass % or more of oxygen.

[0007] The iron powder for deodorization according to one embodiment of the present disclosure has excellent deodorizing and deodorizing effects on various targets.

[0008] Figure 1 is a graph showing the relationship between the decrease in ammonia gas concentration and the elapsed time for Nos. 1 to 6. Figure 2 is a graph showing the relationship between the decrease in hydrogen sulfide gas concentration and the elapsed time for Nos. 1 to 6. Figure 3 is a graph showing the relationship between the decrease in acetic acid gas concentration and the elapsed time for Nos. 1 to 6. Figure 4 is a graph showing the relationship between the decrease in isovaleric acid gas concentration and the elapsed time for Nos. 1 to 6.

[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0010] (1) The iron powder for deodorization according to one embodiment of the present disclosure contains iron as a main component and 0.5% by mass or more of oxygen.

[0011] This iron powder for deodorization contains iron as its main component and 0.5% by mass or more of oxygen, thereby enabling a large specific surface area. More specifically, the iron powder for deodorization has a large specific surface area because its surface is covered with a large number of iron oxide fine particles with a large surface area. As a result, the contact area with the target substance that causes malodor and the like can be increased, improving both the physical adsorption function and the chemical adsorption function. Therefore, this iron powder for deodorization has excellent deodorizing effects for various targets. In this disclosure, "deodorizing effect" refers to a combination of both deodorizing and deodorizing effects.

[0012] (2) In the iron powder for deodorization of (1) above, the specific surface area is 0.1 m ２ According to this aspect, the contact area with the substance to be adsorbed can be made sufficiently large, and both the physical adsorption function and the chemical adsorption function can be further improved.

[0013] (3) The iron powder for deodorization according to (1) or (2) may contain 1.0 mass % or more of magnetite. This is believed to facilitate electrostatic trapping of the target substance. As a result, the physical adsorption function can be further improved.

[0014] (4) In any one of the iron powders for deodorization described above in (1) to (3), it is preferable to include 1.0 mass % or more of wustite. This is believed to facilitate electrostatic trapping of the target substance, thereby further improving the physical adsorption function.

[0015] (5) In the iron powder for deodorization according to any one of (1) to (4), the content of magnetite per 100 parts by mass of oxygen is preferably 200 parts by mass or more and 300 parts by mass or less, and the content of wustite per 100 parts by mass of oxygen is preferably 180 parts by mass or more and 280 parts by mass or less. According to this aspect, the contents of magnetite and wustite can be easily controlled within ranges that make it easy to electrostatically trap the substance to be adsorbed.

[0016] (6) In the iron powder for deodorization according to any one of (1) to (5) above, the content of elements other than iron and oxygen may each be less than 1.0 mass %. According to this aspect, the surface properties of the iron powder for deodorization can be uniformly controlled. As a result, various target substances can be more reliably adsorbed. Therefore, the iron powder for deodorization can easily be improved in versatility with respect to the types of odors, etc.

[0017] In this disclosure, the term "main component" refers to the component with the largest content in terms of mass, for example, a component with a content of 50 mass% or more. The term "specific surface area" refers to the BET specific surface area measured in accordance with JIS-Z8830:2013 (Method for measuring the specific surface area of ​​powders (solids) by gas adsorption).

[0018] [Details of the embodiment of the present disclosure] The embodiment of the present disclosure will be described in detail below. Note that with respect to the numerical values ​​described in this specification, the upper limit value and the lower limit value described can be arbitrarily combined. In this specification, all numerical ranges from the upper limit value to the lower limit value that can be combined are described as suitable ranges.

[0019] [Iron Powder for Deodorization] The iron powder for deodorization contains iron as a main component and 0.5 mass % or more of oxygen.

[0020] This iron powder for deodorization contains iron as its main component and 0.5% by mass or more of oxygen, thereby enabling it to have a large specific surface area. More specifically, the iron powder for deodorization has a large specific surface area because its surface is covered with a large number of iron oxide fine particles, each with a large surface area. As a result, the contact area with the target substance that causes malodors and the like can be increased, improving both the physical adsorption function and the chemical adsorption function. Therefore, this iron powder for deodorization has excellent deodorizing and deodorizing effects on a variety of targets.

[0021] The lower limit of the iron content in the iron powder for deodorization may be 60 mass%, 75 mass%, 85 mass%, 95 mass%, 97 mass%, or 98 mass%. Meanwhile, the upper limit of the iron content in the iron powder for deodorization may be 99.5 mass%. It is believed that the iron powder for deodorization, which contains, for example, pure iron as a main component and has an iron oxide film on its surface, can enhance its deodorizing effect. More specifically, it is believed that the iron powder for deodorization can enhance its deodorizing effect by having a ferrite phase (α phase) as a core and an iron oxide film containing numerous iron oxide fine particles on its surface. Therefore, it is believed that the iron powder for deodorization, which has an iron content equal to or greater than the lower limit and contains a necessary amount of oxygen in the iron oxide film, can exhibit excellent deodorizing effect.

[0022] The lower limit of the oxygen content in the iron powder for deodorization is 0.5% by mass as described above, and may be 0.6% by mass, while the upper limit of the oxygen content in the iron powder for deodorization may be, for example, 30% by mass, 20% by mass, 10% by mass, 5% by mass, 1% by mass, or 0.8% by mass.

[0023] As described above, the iron powder for deodorization preferably has an iron oxide film on its surface. By having the iron oxide film, the iron powder for deodorization can have a complex crystal structure on the surface, thereby increasing the specific surface area. Examples of iron oxide contained in the iron oxide film include magnetite (Fe ３ O ４ ), wustite (FeO), hematite (Fe ２ O ３ ) are listed.

[0024] The iron powder for deodorization preferably contains magnetite. Magnetite is porous and has numerous fine irregularities. Therefore, the specific surface area of ​​the iron powder for deodorization can be easily increased by including magnetite. The lower limit of the magnetite content is preferably 1.0% by mass, more preferably 1.3% by mass, and even more preferably 1.5% by mass, from the viewpoint of, for example, making it easier to electrostatically trap the substance to be adsorbed and further improving the physical adsorption function. On the other hand, the upper limit of the magnetite content may be 45% by mass, 30% by mass, 10% by mass, 5% by mass, 3% by mass, or 2% by mass, from the viewpoint of reducing the production cost of the iron powder for deodorization while obtaining the desired effect.

[0025] The iron powder for deodorization preferably contains wüstite. Wüstite contains a large amount of iron vacancies. Therefore, the specific surface area of ​​the iron powder for deodorization can be increased by including wüstite. The lower limit of the wüstite content is preferably 1.0% by mass, more preferably 1.2% by mass, and even more preferably 1.4% by mass, from the viewpoint of, for example, making it easier to electrostatically trap the adsorption target substance and further improving the physical adsorption function. On the other hand, the upper limit of the wüstite content may be 40% by mass, 30% by mass, 10% by mass, 5% by mass, 3% by mass, or 2% by mass, from the viewpoint of reducing the production cost of the iron powder for deodorization while obtaining the desired effect.

[0026] The iron powder for deodorization may contain only one of magnetite and wustite, but preferably contains both magnetite and wustite.

[0027] The lower limit of the magnetite content per 100 parts by mass of oxygen may be 200 parts by mass or 220 parts by mass. On the other hand, the upper limit of the magnetite content per 100 parts by mass of oxygen may be 300 parts by mass or 280 parts by mass. By controlling the magnetite content per 100 parts by mass of oxygen within the above range, it is easy to appropriately adjust the magnetite content in the iron powder for deodorization. As a result, for example, it becomes easier to electrostatically trap the substance to be adsorbed, and the physical adsorption function can be further improved.

[0028] The lower limit of the wustite content per 100 parts by mass of oxygen may be 180 parts by mass, 200 parts by mass, or 210 parts by mass. Meanwhile, the upper limit of the wustite content per 100 parts by mass of oxygen may be 280 parts by mass, 260 parts by mass, or 240 parts by mass. By controlling the wustite content per 100 parts by mass of oxygen within the above range, it is easy to appropriately adjust the wustite content in the iron powder for deodorization. As a result, for example, it becomes easier to electrostatically trap the substance to be adsorbed, thereby further improving the physical adsorption function.

[0029] The iron powder for deodorization may contain elements other than iron and oxygen within a range that achieves the desired effect. Meanwhile, by reducing the content of elements other than iron and oxygen, the surface properties of the iron powder for deodorization can be controlled uniformly. As a result, the range of application of adsorption target substances can be easily expanded, and various target substances can be more reliably adsorbed. From this perspective, the content of elements other than iron and oxygen in the iron powder for deodorization (content of each element) may be less than 1.0% by mass, 0.6% by mass or less, 0.5% by mass or less, or less than 0.5% by mass.

[0030] In the iron powder for deodorization, the upper limit of the total content of elements other than iron and oxygen is preferably 2.5% by mass, more preferably 2.1% by mass, and even more preferably 1.0% by mass, and may be less than 1.0% by mass. By reducing the total content of elements other than iron and oxygen, the surface properties can be controlled uniformly. As a result, the range of applicable substances to be adsorbed can be easily expanded, and various substances can be more reliably adsorbed.

[0031] Examples of elements other than iron and oxygen include carbon (C), manganese (Mn), and sulfur (S). The upper limit of the carbon content in the iron powder for deodorization is set to 0.05% by weight, and the upper limit of the carbon content in the iron powder for deodorization is set to 0.05% by weight. ３ The upper limit of the manganese content in the iron powder for deodorization may be 0.3 mass%, 0.2 mass%, or 0.15 mass%, from the viewpoint of suppressing the difficulty in determining the correlation between the specific surface area and the adsorption function due to the inclusion of compounds other than iron oxide, such as manganese, manganese, and sulfur. The upper limit of the manganese content in the iron powder for deodorization may be 0.3 mass%, 0.25 mass%, from the viewpoint of suppressing raw material costs. The upper limit of the sulfur content in the iron powder for deodorization may be 0.3 mass%, 0.2 mass%, 0.1 mass%, 0.05 mass%, or 0.01 mass%, from the viewpoint of suppressing a decrease in adsorption ability for sulfur-containing adsorption target substances, such as hydrogen sulfide. Note that, in the iron powder for deodorization, elements other than iron and oxygen (in some cases, elements other than iron and oxygen, carbon, manganese, and sulfur) may be unavoidable impurities. The upper limit of the content of the unavoidable impurities may be 0.3 mass%, 0.2 mass%, or 0.1 mass%.

[0032] The lower limit of the specific surface area of ​​the iron powder for deodorization is 0.1 m from the viewpoint of sufficiently increasing the contact area with the substance to be adsorbed and improving both the physical adsorption function and the chemical adsorption function. ２ / g is preferred, and 0.2m ２ / g is more preferable, and 0.3m ２On the other hand, the upper limit of the specific surface area is, for example, 1.0 m / g, from the viewpoint of facilitating the homogenization of the surface properties of the iron powder for deodorization. ２ / g, and 0.8m ２ / g, and 0.6m ２ / g, and 0.4m ２ / g.

[0033] The lower limit of the particle diameter D50 (median of the particle size distribution for the entire iron powder) of the iron powder for deodorization may be 40 μm, 60 μm, or 70 μm, for example, from the viewpoint of ease of production, etc. On the other hand, the upper limit of the particle diameter D50 may be 250 μm, 150 μm, or 100 μm, from the viewpoint of sufficiently increasing the specific surface area.

[0034] The iron powder for deodorization may be, for example, an aggregate of a large number of iron powders for deodorization. The iron powder for deodorization can be used as a deodorizing and deodorizing material with a wide range of applications, regardless of the type of substance to be adsorbed. Examples of substances to be adsorbed by the iron powder for deodorization include amine gases such as ammonia, trimethylamine, and pyridine, sulfide gases such as hydrogen sulfide, methyl mercaptan, methyl disulfide, and propanethiol, organic gases such as acetic acid, propionic acid, n-butyric acid, isobutyric acid, n-valeric acid, and isovaleric acid, and aldehyde gases such as acetaldehyde and propionaldehyde.

[0035] [Other Embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as falling within the scope of the present invention.

[0036] The present invention will be described in detail below based on examples, but the present invention should not be construed as being limited by the descriptions of these examples.

[0037] [No. 1 to No. 6] The adsorption characteristics of iron powders for deodorization (No. 1 to No. 6), each having the component composition, particle diameter D50, and specific surface area shown in Table 1, for ammonia gas, hydrogen sulfide gas, acetic acid gas, and isovaleric acid gas were investigated. No. 1 is a water-atomized powder produced by crushing molten iron with high-pressure water, followed by rapid cooling and oxidation. No. 2 is a water-atomized powder produced by crushing molten iron with added sulfur with high-pressure water, followed by rapid cooling and oxidation. No. 3 is an iron powder collected with a wet dust collector during the converter process. No. 4 is iron(II) oxide with a high oxygen concentration obtained by heating iron salts such as iron oxalate in a vacuum. Nos. 5 and 6 are water-atomized powders produced by crushing molten iron with high-pressure water, followed by rapid cooling and oxidation, followed by reduction.

[0038] (Composition) The composition of No. 1 to No. 6 was measured by X-ray diffraction (XRD). Carbon (C), manganese (Mn), and sulfur (S) were not measured for No. 3 due to the large variations in their contents among iron powders. The content of each of iron (Fe), carbon (C), manganese (Mn), and sulfur (S) for No. 4 was not measured. Furthermore, in Table 1, "-" indicates that the content was below the measurement limit. In No. 1, No. 2, and No. 4 to No. 6, all elements other than iron (Fe), carbon (C), manganese (Mn), sulfur (S), and oxygen (O) are unavoidable impurities.

[0039] (Particle diameter D50) The particle diameters D50 of No. 1, No. 2, No. 5, and No. 6 were calculated from the particle size distribution (discontinuous values) sieved using a low-tap sieve shaker. The particle diameter D50 of No. 3 was measured using a particle size distribution analyzer (MICROTRAC HRA 9320-X100) using the laser diffraction scattering method. For No. 4, the product specification value was used.

[0040] (Specific Surface Area) The specific surface areas of No. 1 to No. 6 were determined by BET specific surface area measured using a "FlowSorb II 2300" manufactured by Shimadzu Corporation in accordance with JIS-Z8830:2013 (Method for measuring the specific surface area of ​​powders (solids) by gas adsorption).

[0041]

[0042] (Adsorption Characteristics) For each of No. 1 to No. 6, the adsorption characteristics were evaluated by the following test method using ammonia gas, hydrogen sulfide gas, acetic acid gas, and isovaleric acid gas as the substances to be adsorbed.

[0043] First, a test device was prepared by connecting a detector tube to an airbag (sealed container). Next, 200 g of iron powder Nos. 1 to 6 were individually placed into the airbag, and a mixed gas of ammonia gas, hydrogen sulfide gas, acetic acid gas, isovaleric acid gas, and odorless air was injected. The concentrations (ppm) of ammonia gas, hydrogen sulfide gas, acetic acid gas, and isovaleric acid gas in the mixed gas were 100 ppm, 4 ppm, 30 ppm, and 7.5 ppm, respectively. Furthermore, after 30 minutes, 2 hours, and 24 hours, the gas concentrations were measured using the detector tube to evaluate the degree of decrease in the concentration of each adsorption target substance. The test results are shown in Table 2. The relationship between the decrease in ammonia gas concentration and elapsed time is shown in Figure 1, the relationship between the decrease in hydrogen sulfide gas concentration and elapsed time is shown in Figure 2, the relationship between the decrease in acetic acid gas concentration and elapsed time is shown in Figure 3, and the relationship between the decrease in isovaleric acid gas concentration and elapsed time is shown in Figure 4. In Table 2, "0" means that the value is below the lower detection limit. The lower detection limits for ammonia gas, hydrogen sulfide gas, acetic acid gas, and isovaleric acid gas are 0.5 ppm, 0.05 ppm, 0.5 ppm, and 0.38 ppm, respectively.

[0044]

[0045] [Evaluation Results] Nos. 1 to 4 contain iron as the main component and 0.5% by mass or more of oxygen. As a result, Nos. 1 to 4 have excellent adsorption properties for ammonia gas, hydrogen sulfide gas, acetic acid gas, and isovaleric acid gas. Therefore, it can be seen that iron powders Nos. 1 to 4 are suitable as iron powders for deodorizing and eliminating odors.

[0046] Furthermore, comparing No. 1 to No. 4, the adsorption characteristics of hydrogen sulfide gas were poor in No. 2. This is presumably because No. 2 contained 0.975 mass% S, which made it difficult to sufficiently promote the reaction between Fe and S.

[0047] Furthermore, comparing No. 1 to No. 4, No. 3 is iron powder collected in the converter process, and therefore has calcite (Ca(CO ３ )) and other compounds other than iron oxide. As a result, it is presumed that while No. 3 has an extremely large specific surface area, the adsorption properties for, for example, ammonia gas and isovaleric acid gas are not sufficiently correlated with the specific surface area.

[0048] Furthermore, comparing No. 1 to No. 4, No. 1 has a smaller specific surface area than the other iron powders, but has sufficient adsorption properties for all target substances. Meanwhile, No. 4 has excellent adsorption properties, but its extremely high oxygen content poses a problem in terms of production costs, etc.

[0049] The iron powder for deodorization according to one embodiment of the present disclosure is suitable as a versatile deodorizing material.

Claims

1. Iron powder for deodorizing and eliminating odors, whose main component is iron and contains 0.5% or more by mass of oxygen.

2. Specific surface area is 0.1m ２ 2. The iron powder for deodorization according to claim 1, wherein the iron powder has a molecular weight of 1 / g or more.

3. The iron powder for deodorizing and eliminating according to claim 1 or 2, which contains magnetite in an amount of 1.0 mass % or more.

4. The iron powder for deodorizing and eliminating odors according to claim 1 or 2, which contains 1.0 mass % or more of wustite.

5. The iron powder for deodorization according to claim 1 or 2, wherein the magnetite content per 100 parts by mass of oxygen is 200 parts by mass or more and 300 parts by mass or less, and the wustite content per 100 parts by mass of oxygen is 180 parts by mass or more and 280 parts by mass or less.

6. The iron powder for deodorizing and eliminating according to claim 1 or 2, wherein the content of elements other than iron and oxygen is less than 1.0 mass % each.

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