JP7264895B2 - Hexavalent chromium treatment agent, method for treating contaminants containing hexavalent chromium, and method for treating bone meal containing hexavalent chromium - Google Patents

Description

The present invention relates to a treatment agent for hexavalent chromium, a method for treating contaminants containing hexavalent chromium, and a method for treating bone powder containing hexavalent chromium.

Hexavalent chromium may be mixed in the waste water from a cement factory or the like. Such wastewater containing hexavalent chromium is treated to reduce the content of hexavalent chromium before being discharged into public water bodies such as seas, rivers and lakes. For example, Patent Literature 1 describes that hexavalent chromium contained in wastewater is reduced to trivalent chromium and removed by adsorption using pulverized biotite containing divalent iron in crystals.

JP 2018-008215 A

However, the pulverized material described in Patent Document 1 cannot sufficiently reduce hexavalent chromium in waste water to trivalent chromium. That is, the content of hexavalent chromium cannot be sufficiently reduced. Other contaminants, such as hexavalent chromium-containing soil and hexavalent chromium-containing bone meal for ashes, may also require treatment to reduce the hexavalent chromium content. However, for other contaminants, conventional treatments also fail to sufficiently reduce the hexavalent chromium content.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hexavalent chromium treatment agent capable of sufficiently reducing the content of hexavalent chromium contained in contaminants.

The hexavalent chromium treatment agent according to the present invention is a group consisting of L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate. At least one compound (A) selected from, a compound represented by the following formula (b1), a compound represented by the following formula (b2), a compound represented by the following formula (b3), 1, 2, 4 - At least one compound (B) selected from the group consisting of benzenetriol and 1,3,5-benzenetriol, and selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate and at least one compound (C).

In formulas (b1), (b2) and (b3), R is a group represented by --COOH or --COO(CH ₂ ) _n CH ₃ and n represents 0, 1 or 2;

The hexavalent chromium treatment agent of the present invention can sufficiently reduce the content of hexavalent chromium contained in contaminants.

FIG. 1 is a diagram for explaining a method for treating bone powder containing hexavalent chromium. FIG. 2 is a diagram for explaining a method for treating bone powder containing hexavalent chromium. FIG. 3 is a diagram for explaining a method of treating bone powder containing hexavalent chromium.

A form (embodiment) for carrying out the present invention will be described in detail. The present invention is not limited by the contents described in the following embodiments. In addition, the components described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the configurations described below can be combined as appropriate. In addition, various omissions, substitutions, or changes in configuration can be made without departing from the gist of the present invention.

[Embodiment]
<Hexavalent chromium treatment agent>
The hexavalent chromium treatment agent according to the embodiment contains compound (A), compound (B) and compound (C). Compound (A) is at least one selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate. is. The compound (B) includes a compound represented by the following formula (b1), a compound represented by the following formula (b2), a compound represented by the following formula (b3), 1,2,4-benzenetriol, and 1 , 3,5-benzenetriol.

In formulas (b1), (b2) and (b3) above, R is a group represented by --COOH or --COO(CH ₂ ) _n CH ₃ , and n represents 0, 1 or 2;

Compound (C) is at least one selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate.

Conventionally, the method described in Patent Document 1 is known as a treatment method for removing hexavalent chromium from wastewater containing hexavalent chromium (Cr ⁶⁺ ). reducing hexavalent chromium to trivalent chromium (Cr ³⁺ ) with sodium bisulfite or ferrous sulfate as a reducing agent, and precipitating it as an insoluble compound of chromium hydroxide (Cr(OH) ₃ ); Methods for removing the resulting precipitate are also known.

However, conventional treatment methods cannot sufficiently reduce hexavalent chromium in wastewater to trivalent chromium. That is, the content of hexavalent chromium cannot be sufficiently reduced. In contrast, when wastewater containing hexavalent chromium is treated with the hexavalent chromium treatment agent according to the embodiment, the hexavalent chromium in the wastewater can be sufficiently reduced to trivalent chromium. That is, the content of hexavalent chromium can be sufficiently reduced. The details of the wastewater treatment method using the hexavalent chromium treatment agent according to the embodiment will be described later.

Moreover, a safe compound is used for the hexavalent chromium treatment agent according to the embodiment. Therefore, even if wastewater treated with the hexavalent chromium treatment agent according to the embodiment is discharged into public water areas such as seas, rivers, and lakes, it is considered that the impact on the environment is small.

The hexavalent chromium treatment agent according to the embodiment is a composition containing compound (A), compound (B) and compound (C), and may be in the form of powder or tablet.

Compound (A) is at least one selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate. is. A compound (A) may be used individually by 1 type, or may be used in combination of 2 or more types. The compound (A) has an excellent reducing power to reduce hexavalent chromium to trivalent chromium when contacted with waste water containing hexavalent chromium. In addition, hexavalent chromium can be quickly reduced to trivalent chromium. That is, it is excellent in immediate effect.

Among these, L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, erythorbic acid, sodium erythorbate and calcium erythorbate are preferably used. These can be rapidly dissolved when they come into contact with wastewater containing hexavalent chromium, and have excellent reducing power.

L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, erythorbic acid and sodium erythorbate are more preferably used. These are designated as food additives and have high safety. A food additive is designated as a food additive if it satisfies item 1 and item 2 below.

1. Items related to toxicity ・Repeated dose test (confirmation of effects when fed repeatedly)
・Reproduction test, teratogenicity test (confirmation of effects on the next generation)
・Carcinogenicity test ・Antigenicity test (confirmation of possibility of developing allergy)
・Mutagenicity test (confirmation of effects on genes, chromosomes, etc.)
・General pharmacological test (confirmation of effects on biological functions of tested animals)
2. Items related to pharmacokinetics (how it changes and is metabolized in the body)

Furthermore, L-ascorbic acid and sodium L-ascorbate are particularly preferably used. They are superior in reducing power.

Compound (A) preferably has a particle size of 60 mesh or less, more preferably 100 mesh or less. That is, the compound (A) preferably has a size that allows it to pass through a 60-mesh sieve, and more preferably has a size that allows it to pass through a 100-mesh sieve. When the particle size is within the above range, when it comes into contact with waste water containing hexavalent chromium, it becomes easier to dissolve in the waste water, and the immediate effect is further enhanced.

The compound (B) is a compound represented by the above formula (b1), a compound represented by the above formula (b2), a compound represented by the above formula (b3), 1,2,4-benzenetriol, and 1 , 3,5-benzenetriol. A compound (B) may be used individually by 1 type, or may be used in combination of 2 or more types. The compound (B) has an excellent reducing power to reduce hexavalent chromium to trivalent chromium when contacted with waste water containing hexavalent chromium. In addition, hexavalent chromium can be quickly reduced to trivalent chromium. That is, it is excellent in immediate effect. Compound (A) is superior to compound (B) in terms of reducing power and immediate effect. Furthermore, compound (B) has an antioxidant function to prevent oxidation of compound (A). Stability can also be improved by using such a compound (B) in the hexavalent chromium treatment agent according to the embodiment. In other words, it is possible to suppress deterioration during storage from the production of the hexavalent chromium treatment agent until it is used to treat waste water containing hexavalent chromium.

Among these, the compound represented by the above formula (b1), 1,2,4-benzenetriol, or 1,3,5-benzenetriol is preferably used. They are superior in reducing power and antioxidant function. Furthermore, among the compounds represented by the above formula (b1), gallic acid and propyl gallate are more preferably used. These are designated as food additives and have high safety.

Compound (B) preferably has a particle size of 60 mesh or less, more preferably 100 mesh or less. That is, the compound (B) preferably has a size that allows it to pass through a 60-mesh sieve, and more preferably has a size that allows it to pass through a 100-mesh sieve. When the particle size is within the above range, when it comes into contact with waste water containing hexavalent chromium, it becomes easier to dissolve in the waste water, and the immediate effect is further enhanced.

Compound (C) is at least one selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate. A compound (C) may be used individually by 1 type, or may be used in combination of 2 or more types. If the hexavalent chromium treatment agent contains the compound (C), it will dissolve more quickly in the wastewater when it comes into contact with the wastewater containing hexavalent chromium. Compound (C) also has a dehydrating function. By using such a compound (C) in the hexavalent chromium treatment agent according to the embodiment, it becomes difficult to adsorb water during storage, and it becomes difficult to deteriorate.

Among these, anhydrous sodium sulfate is preferably used. If the hexavalent chromium treatment agent contains anhydrous sodium sulfate, it will more rapidly dissolve in the wastewater when it comes into contact with the wastewater containing hexavalent chromium. In addition, anhydrous sodium sulfate has an excellent dehydrating function, and can further suppress deterioration of the hexavalent chromium treatment agent. Furthermore, it is designated as a food additive and has a high degree of safety.

The hexavalent chromium treatment agent according to the embodiment contains compound (A) in an amount of 60 parts by mass or more and 90 parts by mass or less when the total of compound (A), compound (B) and compound (C) is 100 parts by mass. Preferably, the compound (B) is contained in an amount of 5 parts by mass or more and 20 parts by mass or less, and the compound (C) is contained in an amount of 5 parts by mass or more and 20 parts by mass or less. When compound (A), compound (B) and compound (C) are contained in the above amounts, the balance between reducing power and stability can be improved.

The hexavalent chromium treatment agent according to the embodiment may further contain compound (D). Compound (D) is at least one selected from the group consisting of tannic acid and catechin. A compound (D) may be used individually by 1 type, or may be used in combination of 2 or more types. Compound (D) can exhibit reducing power over a long period of time. When compound (D) is included, the hexavalent chromium treatment agent according to the embodiment contains 0 mass of compound (D) with respect to a total of 100 mass parts of compound (A), compound (B) and compound (C). It is preferably contained in an amount of more than 10 parts by mass and not more than 10 parts by mass.

The hexavalent chromium treatment agent according to the embodiment is produced as a powdery composition by appropriately mixing compound (A), compound (B), compound (C), and optionally compound (D), for example. be. Alternatively, the obtained powdery composition may be suitably compressed into tablets.

<Wastewater treatment method containing hexavalent chromium>
In the method for treating wastewater containing hexavalent chromium according to the embodiment, the wastewater containing hexavalent chromium is brought into contact with the hexavalent chromium treatment agent described above, and the hexavalent chromium contained in the wastewater is reduced to trivalent chromium. Including process.

Effluents discharged into public waters by factories, etc. are subject to regulations based on effluent standards. Effluent standards include standards set by the national government (uniform standards) and more stringent standards set by ordinances by prefectures according to the actual conditions of the region (additional standards). Specifically, on a uniform basis, the permissible limit for hexavalent chromium compounds is 0.5 mgCr(VI)/L. As an add-on, for example, the permissible limit for hexavalent chromium compounds is 0.05 mg Cr(VI)/L. Conventional treatment methods may not be able to reduce the hexavalent chromium content to meet these effluent standards. If the content of hexavalent chromium in the wastewater that has been conventionally treated is not sufficiently reduced, it is preferable to further treat the wastewater with the hexavalent chromium treatment agent described above. This generally reduces the content of hexavalent chromium to meet any effluent standards.

For example, by treatment with the hexavalent chromium treatment agent described above, wastewater with a hexavalent chromium content of 0.05 mg/L or more and 1.0 mg/L or less is reduced to a hexavalent chromium content of 0.05 mg/L. can be less than

Specifically, in the method for treating wastewater containing hexavalent chromium according to the embodiment, wastewater containing hexavalent chromium is put into a treatment tank, and the hexavalent chromium treatment agent is added to the treatment tank and stirred. The processing time can be set appropriately. Moreover, it is preferable to add the hexavalent chromium treating agent in an amount of 2.5×10 ⁻³ to 12.5×10 ⁻³ parts by mass to 100 parts by mass of waste water containing hexavalent chromium. When the hexavalent chromium treatment agent is used in the above amount, the content of hexavalent chromium can be sufficiently reduced.

A safe compound is used for the hexavalent chromium treatment agent. Therefore, even if the wastewater treated with the hexavalent chromium treatment agent according to the embodiment is discharged as it is to public water areas such as the sea, rivers, and lakes, the impact on the environment is considered to be small.

[Other embodiments]
<Method for treating soil containing hexavalent chromium and method for treating bone meal containing hexavalent chromium>
In the above-described embodiments, the treatment method was described when the pollutant was wastewater. However, in other embodiments, the contaminant is not limited to wastewater, but may be soil, human or other animal bone meal after incineration, as long as it contains hexavalent chromium. That is, other embodiments include a method for treating soil containing hexavalent chromium and a method for treating bone meal containing hexavalent chromium. In any treatment method, the hexavalent chromium treatment agent described above is preferably used.

First, a method for treating soil containing hexavalent chromium will be described. By the way, the Soil Contamination Countermeasures Law stipulates soil environment standards. Hexavalent chromium is defined as 0.05 mg or less per liter of test solution. Conventional treatment methods (eg reduction treatment, incineration treatment) may not be able to reduce the content of hexavalent chromium so as to meet this standard. If the hexavalent chromium content of the soil treated by the conventional treatment method is not sufficiently reduced, it is preferable to further treat the soil with the hexavalent chromium treatment agent described above. This usually allows the content of hexavalent chromium to be reduced so that the above criteria are also met.

For example, by treatment with the above-described hexavalent chromium treatment agent, the content of hexavalent chromium in soil having a hexavalent chromium content of 0.05 mg or more and 1.0 mg or less per 1 L of the test solution is reduced to 0 per 1 L of the test solution. less than 0.05 mg.

Specifically, in the method for treating soil containing hexavalent chromium according to the embodiment, the hexavalent chromium treatment agent is sprayed onto the soil containing hexavalent chromium. Then, it is preferable to sprinkle water on the soil to which the hexavalent chromium treatment agent has been applied. Sprinkling water causes the hexavalent chromium treatment agent to quickly dissolve. Therefore, hexavalent chromium can be rapidly reduced to trivalent chromium. Moreover, it is preferable to add the hexavalent chromium treatment agent in an amount of 2.5×10 ⁻³ to 50×10 ⁻³ parts by mass to 100 parts by mass of soil containing hexavalent chromium. When the hexavalent chromium treatment agent is used in the above amount, the content of hexavalent chromium can be sufficiently reduced.

A safe compound is used for the hexavalent chromium treatment agent. Therefore, even if the soil treated with the hexavalent chromium treatment agent according to the embodiment is left as it is, it is considered that the impact on the environment is small.

Next, a method for treating bone powder containing hexavalent chromium will be described. Bone meal may contain hexavalent chromium. In the case of scattering the ashes on land, if the ashes are scattered as they are, there is concern about the impact on the environment. Therefore, when the bones are scattered, the bone powder containing hexavalent chromium may be subjected to a reduction treatment or the like to reduce the content of hexavalent chromium. However, conventional treatment methods cannot sufficiently reduce the content of hexavalent chromium. For this reason, it is preferable to treat the bone powder containing hexavalent chromium with the above-mentioned hexavalent chromium treatment agent during the ashes scattering. This can usually sufficiently reduce the content of hexavalent chromium. Bone meal may contain bone fragments.

Specifically, in the method for treating bone powder containing hexavalent chromium according to the embodiment, the hexavalent chromium treatment agent is added to and mixed with the bone powder containing hexavalent chromium. It is preferable to sprinkle water when scattering ashes. Sprinkling water causes the hexavalent chromium treatment agent to quickly dissolve. Therefore, hexavalent chromium can be quickly reduced to trivalent chromium. Moreover, it is preferable to add the hexavalent chromium treatment agent in an amount of 2.5×10 ⁻³ mass parts or more and 50×10 ⁻³ mass parts or less with respect to 100 mass parts of bone powder containing hexavalent chromium. When the hexavalent chromium treatment agent is used in the above amount, the content of hexavalent chromium can be sufficiently reduced.

A safe compound is used for the hexavalent chromium treatment agent. Therefore, even if the bone powder treated with the hexavalent chromium treatment agent according to the embodiment is scattered and left as it is, the impact on the environment is considered to be small.

More specifically, it is preferable to dispose of bone powder containing hexavalent chromium in the following way together with burial in consideration of bereaved families. 1 to 3 are diagrams for explaining a method for treating bone powder containing hexavalent chromium. When burying a tree, first, as shown in FIG. 1, a bone meal hole 11 for burying bone meal is provided in the ground near the tree. Next, soil 12 premixed with a hexavalent chromium treatment agent is put into the bone powder hole 11 . Bone meal 13 is placed on the soil 12 mixed with the hexavalent chromium treatment agent. Finally, the bone powder 13 is covered with soil 12 mixed with a hexavalent chromium treatment agent. Alternatively, first, as shown in FIG. 2, a bone meal hole 21 for burying bone meal is provided in the ground near the tree. Next, bone powder 22 is placed in the bone powder hole 21 . Soil 23 is put on the bone meal 22 . Finally, an aqueous solution 24 in which a hexavalent chromium treatment agent is dissolved is applied over the soil 23 .

In the case of scattering bones on the sea, a toy 31 is used to sprinkle bone meal, as shown in FIG. The toy 31 is provided with a baffle plate 32. - 特許庁First, an aqueous solution in which a hexavalent chromium treatment agent is dissolved is poured into the toy 31 . Sprinkle bone powder onto the flowing aqueous solution to scatter the bones. While the aqueous solution and the bone powder hit the baffle plate 32 and are stirred, the bone powder is discharged to the water surface (sea surface) in a state in which the hexavalent chromium in the bone powder is reduced.

In addition, even in such tree burial and sea scattering, 2.5×10 ⁻³ parts by mass or more and 50×10 ⁻³ parts by mass or less of the hexavalent chromium treatment agent per 100 parts by mass of bone powder containing hexavalent chromium are used. is preferably added in an amount of

Furthermore, the method for treating bone powder containing hexavalent chromium according to the embodiment is not limited to scattering bones on the sea, and may be carried out when scattering bones in water such as lakes and rivers. Specifically, in this case, the hexavalent chromium in the bone powder is reduced, and the bone powder is discharged onto the water surface, specifically, the water surface of a lake or a river.

In the method for treating bone powder containing hexavalent chromium according to the embodiment, the hexavalent chromium treatment agent according to the embodiment described above is used. However, in the method of treating bone powder containing hexavalent chromium according to other embodiments, the following hexavalent chromium treatment agent may be used. In this case as well, since a safe compound is used for this hexavalent chromium treatment agent, the impact on the environment is considered to be small even if the bone powder treated with the hexavalent chromium treatment agent is scattered and left as it is. be done.

[Hexavalent chromium treatment agent]
The hexavalent chromium reducing compound contained in this hexavalent chromium treatment agent is a compound capable of reducing hexavalent chromium to trivalent chromium, and for example, at least acts with hexavalent chromium to have a trivalent reducing property. The following formula (1 ) and the organic compound (AA) shown in ). The structure represented by formula (1) has trivalent reducing properties by acting with hexavalent chromium.

In formula (1), R ¹ , R ² , R ³ , R ⁴ and R ⁵ are each independently a substituent consisting of C, H and O (a It preferably contains an unsaturated carbonyl group, but does not have a reactive functional group such as an aldehyde group or a carboxyl group. Moreover, it is preferable not to have functional groups, such as nitrogen containing groups, such as an amine group and an isocyanate group, and sulfur containing groups, such as a sulfuric acid group. R ¹ or R ² and any of R ³ , R ⁴ or R ⁵ may combine with each other to form a ring.

The compound having the structure represented by formula (1) may be a cyclic hydrocarbon, or an aromatic hydrocarbon composed of a single ring or condensed rings. In addition, in the case of aromatic hydrocarbons, the π bond is actually not limited to the portion of the double bond between carbon 1 and carbon 2 in formula (1), but is delocalized. Moreover, the cyclic hydrocarbon or aromatic hydrocarbon may have a substituent.

The organic compound (AA) preferably has a structure represented by formula (1) and a hydroxyl group, and does not have reactive functional groups such as an aldehyde group and a carboxyl group in the structure.

Further, as the hexavalent chromium reducing compound, in addition to the organic compound (AA), it has a structure represented by the formula (1) having a trivalent reducing property by acting with hexavalent chromium, and hydroxyphenyl It preferably contains an organic compound (BB) which is free of groups, aldehyde groups and carboxyl groups. Moreover, it is preferable not to have functional groups, such as nitrogen containing groups, such as an amine group and an isocyanate group, and sulfur containing groups, such as a sulfuric acid group.

Examples of the organic compound (AA) or (BB) include the following compounds (formulas (2) to (13)) and derivatives thereof. It is also preferred to use a mixture of these in the present invention.

Carbon 2 in the above formulas (2) to (12) corresponds to carbon 2 in the above formula (1), for example.
A hexavalent chromium reducing compound is an organic compound that acts on harmful hexavalent chromium to chemically change it into a harmless compound. This compound can, for example, reduce hexavalent chromium to render it harmless as trivalent chromium.

Commonly known reducing agents include lithium aluminum hydride, sodium borohydride, hydrazine, dibutylaluminum hydride, oxalic acid, and formic acid. Various problems arise when using these representative reducing agents.

When lithium aluminum hydride is used, the agent is a powdery strong reducing agent, but it is flammable and dangerous because it reacts violently with water to generate hydrogen.

When sodium borohydride is used, the drug is slightly hygroscopic and easily decomposed by moisture, so it must be stored in a sealed container. Aqueous solutions generated by moisture such as sweat and rain exhibit strong basicity because the drug is a decomposition product. It is also difficult to handle because it decomposes in water to generate hydrogen.

Hydrazine is a colorless liquid with a pungent odor similar to that of ammonia. It is easily soluble in water, has strong reducing properties, is easy to decompose, and is flammable, making it difficult to handle.

When dibutylaluminum hydride is used, the chemical is a colorless liquid, but it is susceptible to moisture, so it must be stored and used in an inert gas atmosphere, making it difficult to utilize in the atmosphere.

When oxalic acid is used, the drug is toxic because it strongly binds to calcium ions in the blood in the body, and is designated as a non-medical deleterious substance by the Poisonous and Deleterious Substances Control Law.

When formic acid is used, liquid formic acid solutions and vapors are toxic to the skin and eyes, and may even cause irreversible eye damage. In addition, inhalation may cause disorders such as pulmonary edema, so it is not suitable for use. In addition, chronic exposure is considered to have an adverse effect on the liver and kidneys, and it is also considered to be a potential allergen source.

For this reason, the applicant of the present invention conducted extensive research and experiments on hexavalent chromium-reducing compounds and found compounds that met the purpose.
The organic compounds (AA) and (BB) contained as hexavalent chromium reducing compounds have the basic performance of treating hexavalent chromium and rendering it harmless, and are not toxic. Also, (AA) and (BB) are preferably compounds that do not cause mutual decomposition due to their reducing properties, and are compounds that do not react or interfere with each other. As the organic compound, a compound having a basic skeleton represented by the above chemical formula (1) is preferable, and a stable compound composed of C, H, and O atoms is preferable.

The organic compound having the structure represented by the above chemical formula (1) does not have functional groups such as an aldehyde group and a carboxyl group. Moreover, it is preferable not to have functional groups, such as nitrogen containing groups, such as an amine group and an isocyanate group, and sulfur containing groups, such as a sulfuric acid group. Such functional groups are not suitable for hexavalent chromium reducing compounds because they are reactive and may react unexpectedly. The organic compound acts on hexavalent chromium to produce a compound that is not detected as hexavalent chromium, and can detoxify hexavalent chromium.

(Organic compound (AA))
The organic compound (AA) has a structure represented by the above chemical formula (1) and, for example, a hydroxyphenyl group represented by the following chemical formula (15). By having this functional group, it also has an immediate effect, stays stably for a long time, has a reducing action over a long period of time, and is excellent in heat resistance. As the organic compound (AA), a compound that is highly safe and has little burden on the environment is preferable.

In chemical formula (15), R ^a is a monovalent group or a divalent group. Monovalent groups include hydrogen atoms, hydrocarbon groups or oxygen-containing groups. Divalent groups include divalent hydrocarbon groups or divalent oxygen-containing groups. Among these, a hydrogen atom, a monovalent hydrocarbon group, a divalent hydrocarbon group, or a hydroxyl group is preferable because more compatibility can be obtained. Each R ^a is independent and may be the same or different, but adjacent groups of R ^a may combine with each other to form an aromatic ring or an aliphatic ring. Also, R ^a may be bonded to another hydroxyphenyl group R ^a . It is preferable that all of R ^a are not hydrogen atoms at the same time, and the group represented by the chemical formula (15) is a dihydroxyphenyl group or A trihydroxyphenyl group is more preferred, and a 3,4,5-trihydroxyphenyl group is more preferred.

The hydrocarbon group is preferably a hydrocarbon group having 1 to 20 carbon atoms, specifically, an alkyl group having 1 to 20 carbon atoms, an arylalkyl group having 7 to 20 carbon atoms, Examples include an aryl group or a substituted aryl group. For example, methyl group, ethyl group, n-propyl group, isopropyl group, allyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, amyl group, n-pentyl group, neopentyl group , n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decanyl group, 3-methylpentyl group, 1,1-diethylpropyl group, 1,1-dimethylbutyl group, 1- methyl-1-propylbutyl group, 1,1-dipropylbutyl group, 1,1-dimethyl-2-methylpropyl group, 1-methyl-1-isopropyl-2-methylpropyl group, cyclopentyl group, cyclohexyl group, cyclo heptyl group, cyclooctyl group, norbornyl group, adamantyl group, phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, xylyl group, isopropylphenyl group, t-butylphenyl group, naphthyl group, biphenyl group, Terphenyl group, phenanthryl group, anthracenyl group, benzyl group, and cumyl group can be mentioned, and those containing oxygen-containing groups such as methoxy group, ethoxy group, and phenoxy group are also mentioned as hydrocarbon groups (eg, alkoxyl groups). . In addition, unsaturated carboxylic acid esters such as methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, (5-norbornen-2-yl) ester (the unsaturated carboxylic acid is a dicarboxylic acid) If it is an acid, it may be a monoester or a diester) are also included as hydrocarbon groups.

Oxygen-containing groups include hydroxyl groups.
Examples of the organic compound (AA) include the above chemical formulas (2) to (12),
phenol, o-cresol, m-cresol, p-cresol, 2,3-dimethylphenol, 2,5-dimethylphenol, 3,4-dimethylphenol, 3,5-dimethylphenol, 2,4-dimethylphenol, 2 ,6-dimethylphenol, 2,3,5-trimethylphenol, 3,4,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol, 4-tert-butylphenol, BHT (dibutylhydroxytoluene), BHA (butylhydroxyanisole), 2-phenylphenol, 3-phenylphenol, 4-phenylphenol, 3,5-diphenylphenol, 2-naphthylphenol, 3-naphthylphenol, 4-naphthylphenol, 4-tritylphenol, 2- methylresorcinol, 4-methylresorcinol, 5-methylresorcinol, 4-tert-butylcatechol, 2-methoxyphenol, 3-methoxyphenol, 2-propylphenol, 3-propylphenol, 4-propylphenol, 2-isopropylphenol, 3-isopropylphenol, 4-isopropylphenol, 2-methoxy-5-methylphenol, 2-tert-butyl-5-methylphenol, thymol, isothymol, 1-naphthol, 2-naphthol, 2-methyl-1-naphthol, 4-methoxy-1-naphthol, 7-methoxy-2-naphthol,
dihydroxynaphthalenes such as 1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene and 2,6-dihydroxynaphthalene;
tetrahydroxynaphthalene such as 1,3,6,8-tetrahydroxynaphthalene,
methyl 3-hydroxy-naphthalene-2-carboxylate, 9-hydroxyanthracene, 1-hydroxypyrene, 1-hydroxyphenanthrene, 9-hydroxyphenanthrene, bisphenolfluorene, phenolphthalein,
benzophenone derivatives such as 2,3,4-trihydroxybenzophenone and 2,2′,3,4-tetrahydroxybenzophenone;
Tannins such as catechol tannins, pyrogallol tannins, quintuple tannins, gallic tannins, phlorotannins,
flavonoids such as anthocyanins, rutin, quercetin, fisetin, daidzein, hesperetin, hespiridin, chrysin, flavonoids, hesperetin;
catechins such as catechin, gallocatechin, catechin gallate, epicatechin, epicalocatechin, epicatechin gallate, epicalocatechin gallate, procyanidins, and theaflavin;
curcumin, lignans,
rhododendrol [4-(p-hydroxyphenyl)-2-butanol],
Acetylrhododendrol, hexanoylrhododendrol, octanoylrhododendrol, dodecanoylrhododendrol, tetradecanoylrhododendrol, hexadecanoylrhododendrol, octadecanoylrhododendrol, 4-(3-acetoxy butyl)phenylacetate, 4-(3-propanoyloxybutyl)phenylpropanoate, 4-(3-octanoyloxybutyl)phenyloctanoate, 4-(3-palmitoyloxybutyl)phenylpalmitate, etc. modified rhododendrol,
Rhododendrol alkyl ethers such as 4-(3-methoxybutyl)phenol, 4-(3-ethoxybutyl)phenol, 4-(3-octyloxybutyl)phenol,
Rhododendrol-D-glucoside (α or β form), Rhododendrol-D-galactoside (α or β form), Rhododendrol-D-xyloside (α or β form), Rhododendrol-D-maltoside ( Rhododendrol glycosides such as α or β form), etc.
α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and the like can be mentioned.

In addition, derivatives thereof, such as compounds having an alkoxyl group, esters and the like are also included. Specific examples include pyrogallol-1,3-dimethyl ether, pyrogallol-1,3-diethyl ether, 5-propylpyrogallol-1-methyl ether and the like.

The organic compound (AA) includes, for example, compounds having the structure (1,2,3-trihydroxybenzene skeleton) shown in the chemical formula (2) and derivatives thereof. Such compounds have the function of removing hexavalent chromium.

This derivative includes those having substituents such as hydrocarbon groups or oxygen-containing groups at the 4, 5 and 6 positions of the compound represented by the above chemical formula (2). Preferred substituents include a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms and an esterified product having 1 to 20 carbon atoms, more preferably a hydrocarbon group having 1 to 10 carbon atoms and 1 carbon atom. alkoxy groups of up to 20 and esters of 1 to 10 carbon atoms. These groups are as described above. The same applies to derivatives of compounds described later. For example, there are esters of gallic acid such as the compound represented by the above chemical formula (3), compounds represented by the above chemical formula (4) having a plurality of structures represented by the above chemical formula (2) in one molecule, and derivatives of the compounds. . Tannins such as catechol-based tannins, pyrogallol-based tannins, quincunx tannins, gallic tannins, and phlorotannins can be mentioned.

As described above, the substituents to be introduced at the 4, 5 and 6 positions can be introduced according to the respective usage. For example, when used by dissolving in an ester solvent, an ester group can be introduced to improve compatibility.

In the present invention, the organic compound (AA) preferably contains (i) an ester of gallic acid and (ii) at least one compound selected from tannic acid and derivatives thereof, and (i) gallic acid More preferably, it contains an ester and (ii) tannic acid.

Esters of gallic acid have a relatively small molecular weight, so their reducing power is not as high as that of ascorbic acid, but their reducing power is higher than that of tannic acid. demonstrate. Esters of gallic acid are difficult to decompose.

Tannic acid and its derivatives can maintain reducing power over a long period of time. Therefore, the production of hexavalent chromium can be suppressed over a longer period of time. Also, tannic acid and its derivatives are highly safe. Its reducing power is slower than that of ascorbic acid and gallic acid esters, but it is less likely to be decomposed, so it can maintain its reducing power compared to ascorbic acid and gallic acid esters.

Therefore, containing these compounds enables stable reduction over a long period of time. Furthermore, polyphenols are preferred because of their strong reducing properties.

Further, in the above chemical formula (2), hydroxyl groups are present at the 1-, 2-, and 3-positions, but similarly, hydroxyl groups are introduced at the 1-, 2-, and 4-positions (chemical formula (5) above). , 1-, 3-, and 5-positions of which hydroxyl groups are introduced (the above chemical formula (6)) have similar effects. A derivative also has the same effect.

In addition, although three hydroxyl groups are introduced into one aromatic ring in the above chemical formula (2), a compound having one hydroxyl group or a compound having two hydroxyl groups also has a function of removing hexavalent chromium. Such skeletons include, for example, phenol, BHT, compounds of the above chemical formulas (7), (8), and (9), and derivatives thereof.

A compound in which a plurality of aromatic rings are bonded together with a hydroxyl group also has the same effect. Examples include those having one or more hydroxyl groups in the naphthalene ring. For example, compounds having two hydroxyl groups are represented by the above chemical formulas (10) and (11). Derivatives of such compounds also have the function of removing hexavalent chromium, like the compounds described above.

A compound in which one or more hydroxyl groups are introduced at arbitrary positions of anthracene having three aromatic rings in a row exhibits the same function. Such a compound includes, for example, the compound represented by the above chemical formula (12). These derivatives also have a hexavalent chromium removing function.

Examples of compounds represented by the above chemical formula (1) include compounds having a long-chain alkyl group and a composite ring. Such compounds are more organic and less water soluble. On the other hand, however, it has the advantage of being soluble in hydrocarbon solvents because it has a high affinity with organic solvents.

Examples of the compound represented by the above chemical formula (1) include catechins such as catechin, gallocatechin, catechin gallate, epicatechin, epicalocatechin, epicatechin gallate, epicalocatechin gallate, procyanidin, and theaflavin, and derivatives of catechins. It is also preferable to have These catechins are excellent in safety and have high reducing power.

(Organic compound (BB))
The organic compound (BB) has a structure represented by the above chemical formula (1) but does not have a hydroxyphenyl group represented by, for example, the above chemical formula (15). Examples of the organic compound (BB) include compounds having a heterocycle. Heterocycles include furan, chromene, isochromene, xanthene and the like. Such derivatives include, for example, the compound having the structure represented by the above chemical formula (13) and its derivatives, erythorbic acid and its derivatives, and 4-hydroxyfuran-2(5H)-one. Such compounds have the function of removing hexavalent chromium.

Derivatives of ascorbic acid include, but are not limited to, ascorbic acid esters, ascorbic acid phosphates, ascorbic acid sulfates, ascorbic acid glucoside (2-O-α-D-glucopyranosyl-L-ascorbic acid), and ascorbic acid. acid glucosamine, dehydroascorbic acid, and the like.

Derivatives of erythorbic acid include erythorbic acid esters and the like.
In the present invention, the organic compound (BB) is preferably at least one compound selected from ascorbic acid and erythorbic acid, more preferably ascorbic acid. Since the compound easily decomposes, its effect cannot be realized over a long period of time, and it is excellent in safety, has high reducing power, and has high immediate effect. The compound (BB) does not react with or is compatible with the organic compound (AA), and is not decomposed by the compound (AA), so that it can be suitably mixed with the treatment liquid.

As described above, hexavalent chromium can be detoxified and removed if the compound contains the basic skeleton represented by the above chemical formula (1) in the molecule.

(Preferred embodiment of hexavalent chromium reducing compound)
As the hexavalent chromium reducing compound, at least one selected from compounds (Ai) and tannins (A-ii) represented by the following formula (Ai) is preferable, and represented by the following formula (Ai): It is more preferable to use the compound (Ai) and tannin (A-ii) in combination.

Compound (Ai) is represented by the following formula (Ai).

In the formula, n represents 0, 1 or 2. That is, compound (Ai) has a benzene, naphthalene or anthracene structure.
R ¹¹ to R ¹⁸ each independently represent a hydrogen atom, a hydroxy group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a group represented by formula (ai) below. Here, R19 represents an alkyl group having 1 to 4 carbon atoms.

The alkyl group having 1 to 4 carbon atoms includes methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group and t-butyl group. The alkoxy group having 1 to 4 carbon atoms includes methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, s-butoxy and t-butoxy.

When n is 0, at least one of R ¹¹ to R ¹⁴ , R ¹⁶ and R ¹⁷ is a hydroxy group. When two of R ¹¹ to R ¹⁴ , R ¹⁶ and R ¹⁷ are hydroxy groups and three of them are hydroxy groups, the ability to reduce hexavalent chromium increases, which is preferable.

When n is 1 or 2, at least one of R ¹¹ to R ¹⁸ is a hydroxy group. When n is 1 or 2, two of R ¹¹ to R ¹⁸ being hydroxy groups and three being hydroxy groups are preferable because the ability to reduce hexavalent chromium increases.

When n is 2, a plurality of R ¹⁵ may be the same or different, and the same applies to R ¹⁸ .
R ¹⁶ and R ¹⁷ may be combined with each other to form a 5- or 6-membered ring, and the atoms constituting the ring may include oxygen atoms in addition to carbon atoms. . Further, the ring may have an alkyl group having 1 to 16 carbon atoms as a substituent. The alkyl group having 1 to 16 carbon atoms may be linear or branched.

Specific examples of the compound (Ai) include the compounds represented by formulas (2), (3), and (5) to (12) described above, and the exemplary compounds described above. Compound (Ai) may be used alone or in combination of two or more.

Tannins (A-ii) may be hydrolyzable tannins or condensed tannins. Examples of hydrolyzable tannins include gallotannins such as tannic acid (the compound represented by the above formula (4)), ellagitannins, and the like. Hydrolyzable tannins are preferably used from the viewpoint of preparing a treatment agent to be described later. Tannins (A-ii) may be used alone or in combination of two or more.

In the compound (Ai) and tannin (A-ii), the carbon to which the hydroxy group is bonded corresponds to carbon 2 in the above formula (1), for example.
As hexavalent chromium reducing compounds, in addition to compound (Ai) and tannin (A-ii), compound (Bi) represented by formula (Bi) below and compound (B-ii) represented by formula (B-ii) below It is preferable to use at least one selected from compounds (B-ii).

In the formula, X represents any one of the groups represented by formulas (bi) to (b-iii) below. Here, о represents an integer of 0-3, p represents an integer of 1-3, and q represents an integer of 1-17.

Specific examples of the compound (Bi) and the compound (B-ii) include the compound represented by the formula (13) described above and the exemplary compounds described above. Compound (Bi) and compound (B-ii) may be used alone or in combination of two or more. Further, compound (Bi) and compound (B-ii) may be used in combination.

The ratio of the organic compounds (AA) and (BB) in this hexavalent chromium treatment agent is not particularly limited as long as the effect of the present invention is exhibited. It is preferably 90:10 to 50, more preferably 50 to 80:20 to 50, even more preferably 50 to 70:30 to 50 (provided that (AA) and (BB) total 100% by weight).

When the hexavalent chromium treatment agent contains (i) an ester of gallic acid, (ii) at least one compound selected from tannic acid and its derivatives, and an organic compound (BB), the Although it is not particularly limited as long as it is effective, the ratio by weight ((i):(ii):(BB)) is preferably 1 to 20:30 to 89:10 to 50, and 3 to 17:33 to 77. :20 to 50 is more preferred, and 5 to 15:35 to 65:30 to 50 is more preferred (provided that the total of (i), (ii) and (BB) is 100% by weight). As the organic compound (BB), ascorbic acid and/or erythorbic acid are preferable because they are not compatible with compounds (i) and (ii), are not incorporated into compound (ii), and can be preferably reduced. In addition, these quantitative ratios are preferred because they are easily soluble in both water and organic solvents. The treatment liquid is preferable because long-term reliability can be obtained.

Further, when the hexavalent chromium treatment agent contains compound (Ai) and tannin (A-ii), the ratio of compound (Ai) and tannin (A-ii) is Although not particularly limited, the weight percent ratio ((Ai):(A-ii)) is preferably 11 to 70:30 to 89, more preferably 23 to 67:33 to 77, and 35 to 50:50 to 65 is more preferred (provided that the sum of (Ai) and (Aii) is 100% by weight). Thereby, a state in which hexavalent chromium is reduced can be maintained for a long period of time.

Further, when the hexavalent chromium treatment agent contains compound (Ai), tannin (A-ii), and compound (Bi) and/or (B-ii), compound (Ai), The total ratio of tannin (A-ii) and compounds (B-i) and (B-ii) is not particularly limited as long as the effect of the present invention is exhibited, but the weight % ratio ((A-i):(A -ii): the sum of (Bi) and (B-ii)), preferably 1 to 20:30 to 89:10 to 50, more preferably 3 to 17:33 to 77:20 to 50, 5 ~15:35 ~ 65:30 ~ 50 is more preferable (provided that the sum of (Ai), (A-ii), (Bi) and (B-ii) is 100% by weight) said treatment A liquid is preferred because it provides long-term reliability.

The hexavalent chromium treating agent used in the method for treating bone powder containing hexavalent chromium according to other embodiments may contain a solvent in addition to the hexavalent chromium reducing compound described above. Solvents include water, alcohols having 1 to 3 carbon atoms (propanol, isopropanol (IPA), methanol and ethanol), and the like. A solvent may be used individually by 1 type, or may be used in combination of 2 or more type. In this case, the hexavalent chromium treatment agent contains a hexavalent chromium reducing compound in an amount of, for example, 0.01 to 10.0% by mass.

（式（ｂ１）、（ｂ２）および（ｂ３）中、Ｒは、－ＣＯＯＨまたは－ＣＯＯ（ＣＨ₂）_nＣＨ₃で表される基であり、ｎは０、１または２を表す。）
上記６価クロム処理剤によれば、汚染物質に含まれる６価クロムの含有量を十分に低減できる。As described above, the present invention relates to the following.
[1] at least one compound selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate ( AA), a compound represented by the following formula (b1), a compound represented by the following formula (b2), a compound represented by the following formula (b3), 1,2,4-benzenetriol, and 1,3 ,5-benzenetriol, and at least one compound (C) selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate. A hexavalent chromium treatment agent comprising.

(In formulas (b1), (b2) and (b3), R is a group represented by —COOH or —COO(CH ₂ ) _n CH ₃ , and n represents 0, 1 or 2.)
According to the hexavalent chromium treatment agent, the content of hexavalent chromium contained in contaminants can be sufficiently reduced.

[2] When the total of compound (A), compound (B) and compound (C) is 100 parts by mass, compound (A) is added in an amount of 60 parts by mass or more and 90 parts by mass or less, and compound (B) is added in an amount of 5 parts by mass. The hexavalent chromium treating agent according to [1], which contains the compound (C) in an amount of 5 parts by mass or more and 20 parts by mass or less in an amount of 20 parts by mass or more.
When compound (A), compound (B) and compound (C) are contained in the above amounts, the balance between reducing power and stability can be improved.

[3] The hexavalent chromium according to [1] or [2], wherein the compound (A) is L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, erythorbic acid, or sodium erythorbate. Processing agent.
Containing the above compound (A), which is designated as a food additive, can improve safety.

[4] of [1] to [3], wherein the compound (B) is the compound represented by the formula (b1), 1,2,4-benzenetriol, or 1,3,5-benzenetriol The hexavalent chromium treatment agent according to any one of the above.
When the compound (B) is contained, the reducing power and the antioxidant function can be improved.

[5] The hexavalent chromium treatment agent according to any one of [1] to [4], wherein the compound (C) is anhydrous sodium sulfate.
When the above compound (C) is contained, the hexavalent chromium treatment agent will dissolve in the waste water more quickly. Moreover, the deterioration of the hexavalent chromium treatment agent can be further suppressed, and the safety of the hexavalent chromium treatment agent can be improved.

[6] The hexavalent chromium treatment agent according to any one of [1] to [5], further comprising at least one compound (D) selected from the group consisting of tannic acid and catechin.
When the above compound (D) is included, the hexavalent chromium treatment agent can exert its reducing power over a long period of time.

[7] A step of contacting a contaminant containing hexavalent chromium with the hexavalent chromium treatment agent according to any one of [1] to [6] to reduce the hexavalent chromium contained in the contaminant. A method of treating contaminants containing hexavalent chromium, comprising:
According to the above treatment method, the content of hexavalent chromium contained in the contaminants can be sufficiently reduced.

[8] The contaminant containing hexavalent chromium according to [7], wherein the contaminant containing hexavalent chromium is wastewater containing hexavalent chromium, soil containing hexavalent chromium, or bone meal containing hexavalent chromium. Processing method.
According to the treatment method described above, the content of hexavalent chromium contained in wastewater containing hexavalent chromium, soil containing hexavalent chromium, or bone powder containing hexavalent chromium can be sufficiently reduced.

（式（ｂ１）、（ｂ２）および（ｂ３）中、Ｒは、－ＣＯＯＨまたは－ＣＯＯ（ＣＨ₂）_nＣＨ₃で表される基であり、ｎは０、１または２を表す。）[9] A step of contacting bone powder containing hexavalent chromium with a hexavalent chromium treatment agent to reduce hexavalent chromium contained in the bone powder, wherein the hexavalent chromium treatment agent is L-ascorbic acid, L - At least one compound (A) selected from the group consisting of sodium ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate, and the following formula (b1) from the group consisting of a compound represented by the following formula (b2), a compound represented by the following formula (b3), 1,2,4-benzenetriol, and 1,3,5-benzenetriol Bone powder containing hexavalent chromium, containing at least one selected compound (B) and at least one compound (C) selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate. How to handle.

(In formulas (b1), (b2) and (b3), R is a group represented by —COOH or —COO(CH ₂ ) _n CH ₃ , and n represents 0, 1 or 2.)

[10] In the step of reducing the hexavalent chromium contained in the bone meal, a bone meal hole for burying the bone meal is provided in the ground of the soil, and the soil prepared by mixing the hexavalent chromium treatment agent in the bone meal hole in advance. and placing bone meal on the soil mixed with the hexavalent chromium treatment agent, and then applying the soil mixed with the hexavalent chromium treatment agent on top of the bone meal. A method for treating bone meal containing hexavalent chromium.

[11] The step of reducing the hexavalent chromium contained in the bone meal includes providing a bone meal hole for burying bone meal in the ground of the soil, placing bone meal in the bone meal hole, and placing soil on the bone meal. The method for treating bone powder containing hexavalent chromium according to [9], which is a step of applying an aqueous solution in which the hexavalent chromium treatment agent is dissolved and then applying an aqueous solution of the hexavalent chromium treatment agent over the soil.

[12] The step of reducing the hexavalent chromium contained in the bone powder includes pouring an aqueous solution in which the hexavalent chromium treatment agent is dissolved in a toy provided with baffles, and scattering the bone powder against the flowing aqueous solution. The method for treating bone powder containing hexavalent chromium according to [9], wherein the bone powder is released onto the surface of the water while the aqueous solution and the bone powder hit the baffle and are stirred.
According to the above treatment method, the content of hexavalent chromium contained in bone powder containing hexavalent chromium can be sufficiently reduced.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[Example]
<Hexavalent chromium treatment agent>
[Example 1-1-1]
90 parts by mass of sodium L-ascorbate (100 mesh or less) as compound (A), 5 parts by mass of propyl gallate (100 mesh or less) as compound (B), and 5 parts by mass of anhydrous sodium sulfate as compound (C) in a mortar. and mixed with a pestle to obtain a hexavalent chromium treatment agent.

[Example 1-1-2]
80 parts by mass of sodium L-ascorbate (100 mesh or less) as compound (A), 10 parts by mass of propyl gallate (100 mesh or less) as compound (B), and 10 parts by mass of anhydrous sodium sulfate as compound (C) in a mortar. and mixed with a pestle to obtain a hexavalent chromium treatment agent.

[Example 1-1-3]
70 parts by mass of sodium L-ascorbate (100 mesh or less) as compound (A), 15 parts by mass of propyl gallate (100 mesh or less) as compound (B), and 15 parts by mass of anhydrous sodium sulfate as compound (C) in a mortar. and mixed with a pestle to obtain a hexavalent chromium treatment agent.

[Example 1-1-4]
60 parts by mass of sodium L-ascorbate (100 mesh or less) as compound (A), 20 parts by mass of propyl gallate (100 mesh or less) as compound (B), and 20 parts by mass of anhydrous sodium sulfate as compound (C) in a mortar. and mixed with a pestle to obtain a hexavalent chromium treatment agent.

[Examples 2-1-1 to 2-1-4]
Same as Examples 1-1-1 to 1-1-4 except that L-ascorbic acid (100 mesh or less) was used as compound (A) instead of sodium L-ascorbate (100 mesh or less). to obtain a hexavalent chromium treatment agent.

[Example 3-1-1]
In the same manner as in Example 1-1-1, except that L-ascorbic acid 2-glucoside (100 mesh or less) was used as compound (A) instead of sodium L-ascorbate (100 mesh or less). A hexavalent chromium treatment agent was obtained.

<Wastewater treatment>
[Example 1-2-1]
2.5 mg of the hexavalent chromium treatment agent prepared in Example 1-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Example 1-2-2]
5.0 mg of the hexavalent chromium treatment agent prepared in Example 1-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Example 1-2-3]
12.5 mg of the hexavalent chromium treatment agent prepared in Example 1-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Examples 1-2-4 to 1-2-6]
Wastewater treatment was carried out in the same manner as in Examples 1-2-1 to 1-2-3, respectively, except that wastewater containing hexavalent chromium (wastewater with a Cr ⁶⁺ concentration of 0.5 mg/L) was used. rice field.

[Examples 1-2-7 to 1-2-9]
Wastewater treatment was carried out in the same manner as in Examples 1-2-1 to 1-2-3, respectively, except that wastewater containing hexavalent chromium (wastewater with a Cr ⁶⁺ concentration of 1.0 mg/L) was used. rice field.

[Examples 1-2-10 to 1-2-18]
Wastewater treatment was carried out in the same manner as in Examples 1-2-1 to 1-2-9, respectively, except that the hexavalent chromium treatment agent prepared in Example 1-1-2 was used.

[Examples 1-2-19 to 1-2-27]
Wastewater treatment was carried out in the same manner as in Examples 1-2-1 to 1-2-9, respectively, except that the hexavalent chromium treatment agent prepared in Example 1-1-3 was used.

[Examples 1-2-28 to 1-2-36]
Wastewater treatment was carried out in the same manner as in Examples 1-2-1 to 1-2-9, respectively, except that the hexavalent chromium treatment agent prepared in Example 1-1-4 was used.

[Example 2-2-1]
2.5 mg of the hexavalent chromium treating agent prepared in Example 2-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Example 2-2-2]
5.0 mg of the hexavalent chromium treatment agent prepared in Example 2-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Example 2-2-3]
12.5 mg of the hexavalent chromium treatment agent prepared in Example 2-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Examples 2-2-4 to 2-2-6]
Wastewater treatment was carried out in the same manner as in Examples 2-2-1 to 2-2-3, respectively, except that wastewater containing hexavalent chromium (wastewater with a Cr ⁶⁺ concentration of 0.5 mg/L) was used. rice field.

[Examples 2-2-7 to 2-2-9]
Wastewater treatment was carried out in the same manner as in Examples 2-2-1 to 2-2-3, respectively, except that wastewater containing hexavalent chromium (wastewater with a Cr ⁶⁺ concentration of 1.0 mg/L) was used. rice field.

[Examples 2-2-10 to 2-2-18]
Wastewater treatment was carried out in the same manner as in Examples 2-2-1 to 2-2-9, respectively, except that the hexavalent chromium treatment agent prepared in Example 2-1-2 was used.

[Examples 2-2-19 to 2-2-27]
Wastewater treatment was carried out in the same manner as in Examples 2-2-1 to 2-2-9, respectively, except that the hexavalent chromium treatment agent prepared in Example 2-1-3 was used.

[Examples 2-2-28 to 2-2-36]
Wastewater treatment was carried out in the same manner as in Examples 2-2-1 to 2-2-9, respectively, except that the hexavalent chromium treatment agent prepared in Example 2-1-4 was used.

[Example 3-2-1]
12.5 mg of the hexavalent chromium treatment agent prepared in Example 3-1-1 was added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred. , conducted wastewater treatment.

[Example 3-2-2]
Wastewater treatment was carried out in the same manner as in Example 3-2-1, except that wastewater containing hexavalent chromium (wastewater with a Cr ⁶⁺ concentration of 0.5 mg/L) was used.

[Example 3-2-3]
Wastewater treatment was carried out in the same manner as in Example 3-2-1, except that wastewater containing hexavalent chromium (wastewater with a Cr ⁶⁺ concentration of 1.0 mg/L) was used.

[Measurement of hexavalent chromium concentration]
The concentration of hexavalent chromium was measured for water after wastewater treatment with a hexavalent chromium treatment agent. Specifically, the concentration of hexavalent chromium was measured according to JIS K 0102 65.2.1 by diphenylcarbazide absorption photometry. In Examples 1-2-1 to 1-2-36, Examples 2-2-1 to 2-2-36, and Examples 3-2-1 to 3-2-3, 6 in water after wastewater treatment The concentration of valent chromium was less than 0.05 mg/L.

<Stability>
[Example 1-3-1]
The hexavalent chromium treatment agent prepared in Example 1-1-1 was stored in a room at a temperature of 40° C. and a humidity of 80% RH for 2 months. After that, 2.5 mg of the hexavalent chromium treatment agent after storage is added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred to perform waste water treatment. rice field.

[Example 1-3-2]
Wastewater treatment was carried out in the same manner as in Example 1-3-1, except that the hexavalent chromium treatment agent prepared in Example 1-1-2 was used.

[Example 1-3-3]
Wastewater treatment was carried out in the same manner as in Example 1-3-1, except that the hexavalent chromium treatment agent prepared in Example 1-1-3 was used.

[Example 1-3-4]
Wastewater treatment was carried out in the same manner as in Example 1-3-1, except that the hexavalent chromium treatment agent prepared in Example 1-1-4 was used.

[Comparative Example 1-1-1]
90 parts by mass of sodium L-ascorbate (100 mesh or less) as compound (A) and 5 parts by mass of propyl gallate (100 mesh or less) as compound (B) are placed in a mortar, mixed with a pestle, and treated with hexavalent chromium. got the drug. The prepared hexavalent chromium treatment agent was stored in a room at a temperature of 40° C. and a humidity of 80% RH for two months. After that, 2.5 mg of the hexavalent chromium treatment agent after storage is added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred to perform waste water treatment. rice field.

[Comparative Example 2-1-1]
90 parts by mass of sodium L-ascorbate (100 mesh or less) as compound (A) and 5 parts by mass of anhydrous sodium sulfate as compound (C) were placed in a mortar and mixed with a pestle to obtain a hexavalent chromium treatment agent. The prepared hexavalent chromium treatment agent was stored in a room at a temperature of 40° C. and a humidity of 80% RH for two months. After that, 2.5 mg of the hexavalent chromium treatment agent after storage is added to 100 g of waste water containing hexavalent chromium (waste water with a Cr ⁶⁺ concentration of 0.14 mg/L) and stirred to perform waste water treatment. rice field.

[Measurement of hexavalent chromium concentration]
The concentration of hexavalent chromium was measured for water after wastewater treatment with a hexavalent chromium treatment agent. Specifically, the concentration of hexavalent chromium was measured according to JIS K 0102 65.2.1 by diphenylcarbazide absorption photometry. In Examples 1-3-1 to 1-3-4, the concentration of hexavalent chromium in the water after wastewater treatment was less than 0.05 mg/L. On the other hand, in Comparative Examples 1-1-1 and 2-1-1, the concentration of hexavalent chromium in the water after wastewater treatment exceeded 0.05 mg/L.

In addition, even when soil containing hexavalent chromium or bone powder containing hexavalent chromium is treated with the hexavalent chromium treatment agent prepared in the example, the concentration of hexavalent chromium can be reduced in the same manner as in the wastewater treatment described above. it is conceivable that.

<Simulated processing of bone powder processing>
[Example 4-1]
A filter paper was immersed in an aqueous solution of potassium dichromate (concentration: 1% by mass) and then dried to obtain a filter paper containing hexavalent chromium. This was used instead of bone meal containing hexavalent chromium.
The hexavalent chromium treatment agent prepared in Example 1-1-1 and sand were mixed and spread on a sieve. A filter paper containing hexavalent chromium was placed thereon. Furthermore, the filter paper containing hexavalent chromium was covered with a mixture of a hexavalent chromium treating agent and sand. Also, a container was prepared under the sieve. Water was poured over the mixture covering the filter paper containing hexavalent chromium, and the water passed through the sieve was collected in a container.

[Examples 4-2 to 4-4]
A simulated treatment was performed in the same manner as in Example 4-1, except that the hexavalent chromium treatment agents prepared in Examples 1-1-2 to 1-1-4 were used.

[Preparation Example 1]
A mixed solvent was prepared by mixing water and IPA at a ratio of 50:50 (% by mass).
0.5 g of the compound represented by the chemical formula (3), 2.5 g of the compound represented by the chemical formula (4), and 2.0 g of the compound represented by the chemical formula (13) were mixed with a mixed solvent, homogenized, and treated with hexavalent chromium. got the drug. Here, the mixed solvent was used so that the total amount of the hexavalent chromium treating agent was 500 g. The kinematic viscosity of the treating agent at 25°C was 3.7 (cSt). The kinematic viscosity was measured at a temperature of 25.0° C. using a mixed solvent of IPA and water (1 vol:1 vol) as a solvent using an Ubbelohde viscometer.

[Example 4-5]
A simulated treatment was performed in the same manner as in Example 4-1, except that the hexavalent chromium treatment agent prepared in Preparation Example 1 was used.

[Comparative Example 4-1]
A simulated treatment was performed in the same manner as in Example 4-1, except that the sieve was covered with only sand without using a hexavalent chromium treatment agent, and a filter paper containing hexavalent chromium was placed thereon. .

[Measurement of hexavalent chromium concentration]
The collected water was measured for the concentration of hexavalent chromium. Specifically, the concentration of hexavalent chromium was measured according to JIS K 0102 65.2.1 by diphenylcarbazide absorption photometry. In Examples 4-1 to 4-5, the concentration of hexavalent chromium in water after the simulated treatment was less than 0.05 mg/L. On the other hand, in Comparative Example 4-1, the concentration of hexavalent chromium in water after the simulated treatment exceeded 0.05 mg/L.

11 Bone meal hole 12 Soil mixed with hexavalent chromium treatment agent 13 Bone meal 21 Bone meal hole 22 Bone meal 23 Soil 24 Aqueous solution of hexavalent chromium treatment agent 31 Toy 32 Baffle board

Claims (12)

at least one compound (A) selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate; ,
A compound represented by the following formula (b1), a compound represented by the following formula (b2), a compound represented by the following formula (b3), 1,2,4-benzenetriol, and 1,3,5-benzene at least one compound (B) selected from the group consisting of triols;
At least one compound (C) selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate,
Hexavalent chromium treatment agent.

(In formulas (b1), (b2) and (b3), R is a group represented by —COOH or —COO(CH ₂ ) _n CH ₃ , and n represents 0, 1 or 2.) When the total of compound (A), compound (B) and compound (C) is 100 parts by mass, compound (A) in an amount of 60 parts by mass or more and 90 parts by mass or less and compound (B) in an amount of 5 parts by mass or more containing compound (C) in an amount of 5 parts by mass or more and 20 parts by mass or less, in an amount of 20 parts by mass or less;
The hexavalent chromium treatment agent according to claim 1. wherein the compound (A) is L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, erythorbic acid, or sodium erythorbate;
The hexavalent chromium treating agent according to claim 1 or 2. The compound (B) is the compound represented by the formula (b1), 1,2,4-benzenetriol, or 1,3,5-benzenetriol.
The hexavalent chromium treatment agent according to any one of claims 1 to 3. The compound (C) is anhydrous sodium sulfate,
The hexavalent chromium treating agent according to any one of claims 1 to 4. Furthermore, containing at least one compound (D) selected from the group consisting of tannic acid and catechin,
The hexavalent chromium treatment agent according to any one of claims 1 to 5. contacting a contaminant containing hexavalent chromium with the hexavalent chromium treatment agent according to any one of claims 1 to 6 to reduce the hexavalent chromium contained in the contaminant;
A method for treating contaminants containing hexavalent chromium. The contaminant containing hexavalent chromium is wastewater containing hexavalent chromium, soil containing hexavalent chromium, or bone meal containing hexavalent chromium,
The method for treating contaminants containing hexavalent chromium according to claim 7. contacting bone powder containing hexavalent chromium with a hexavalent chromium treatment agent to reduce hexavalent chromium contained in the bone powder;
The hexavalent chromium treatment agent is selected from the group consisting of L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, L-ascorbic acid 2-glucoside, erythorbic acid, sodium erythorbate, and calcium erythorbate. at least one compound (A);
A compound represented by the following formula (b1), a compound represented by the following formula (b2), a compound represented by the following formula (b3), 1,2,4-benzenetriol, and 1,3,5-benzene at least one compound (B) selected from the group consisting of triols;
At least one compound (C) selected from the group consisting of anhydrous sodium sulfate, anhydrous potassium sulfate, anhydrous magnesium sulfate, and anhydrous calcium sulfate,
A method for treating bone meal containing hexavalent chromium.

(In formulas (b1), (b2) and (b3), R is a group represented by —COOH or —COO(CH ₂ ) _n CH ₃ , and n represents 0, 1 or 2.) The step of reducing the hexavalent chromium contained in the bone meal comprises providing a bone meal hole for burying the bone meal in the ground of the soil, placing soil mixed with the hexavalent chromium treatment agent in advance into the bone meal hole, A step of placing bone powder on the soil mixed with the hexavalent chromium treatment agent, and then applying soil mixed with the hexavalent chromium treatment agent on top of the bone meal.
The method for treating bone powder containing hexavalent chromium according to claim 9. The step of reducing the hexavalent chromium contained in the bone meal comprises providing a bone meal hole for burying the bone meal in the ground of the soil, placing bone meal in the bone meal hole, putting soil on the bone meal, A step of pouring an aqueous solution of the hexavalent chromium treatment agent over the soil,
The method for treating bone powder containing hexavalent chromium according to claim 9. The step of reducing the hexavalent chromium contained in the bone powder includes flowing an aqueous solution in which the hexavalent chromium treatment agent is dissolved in a toy provided with a baffle plate, sprinkling bone powder against the flowing aqueous solution, and removing the baffle. A step in which the bone powder is released onto the water surface while the aqueous solution and the bone powder hit a plate and are stirred.
The method for treating bone powder containing hexavalent chromium according to claim 9.

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