TW201412357A - A composition for decomposing a chemical substance and a method for decomposing a chemical substance by using the composition - Google Patents

Abstract

The purpose of the present invention is to provide: a chemical substance decomposing agent composition which has a good balance between suppression of metal corrosion properties and sufficient ability of decomposing a chemical substance; and a method for decomposing a chemical substance using the chemical substance decomposing agent composition. In order to achieve the above-described purpose, the present invention provides: a chemical substance decomposing agent composition which is characterized by containing (A) a persulfate salt, (B) sodium silicate and (C) a carbonate that is selected from among alkali metal carbonates, alkaline earth metal carbonates and mixtures of these carbonates; and a method for decomposing a chemical substance using the composition.

Description

Chemical substance decomposing agent composition and decomposition treatment method of chemical substance using the same

The present invention relates to a chemical decomposition agent composition and a chemical decomposition treatment method using the same, which can be efficiently decomposed by being added to a soil contaminated with a chemical substance.

In the past, chemical substances such as organic chlorine compounds have been widely used as detergents in semiconductor factories, laundry facilities, and the like. However, such use has been avoided in recent years due to their heavy environmental load. However, all of the chemicals used are already mixed into the soil or groundwater, and land reuse becomes a major social problem. Therefore, various methods are used to purify the contaminated soil or water.

Although physical methods for removing contaminated soil or water, or biological or chemical methods for decomposing pollutants are well known, physical methods have the disadvantage of carrying out contaminated soil. Next, a secondary treatment is required. And, although biological will be pollutants The method of decomposing has been reviewed, and even if it has the advantage of being small in environmental load, it is difficult to apply a highly decomposable chemical substance such as a highly concentrated pollutant or an organic chlorine compound, and it takes a long time to decompose. In contrast, in the chemical decomposition method, it is possible to decompose pollutants in the field, and it is not necessary to treat the secondary substances, and it is possible to decompose high-concentration pollutants and hard-to-decompose chemical substances such as organic chlorine compounds early. The ground is studied.

As a method of chemical decomposition, a method of oxidatively decomposing a pollutant by using hydrogen peroxide or persulfate is known. As a method of decomposition treatment, it is generally a method of injecting into a foundation, and since hydrogen peroxide is unstable, decomposition is rapid, and decomposition is immediately performed in the injected ground, and the purification range becomes extremely narrow. On the other hand, due to the stability of persulfate, more has been studied. (Refer to Patent Documents 1 to 4)

It is not necessary to excavate the contaminated soil, but put it in place. To purify the low-cost purification, it is necessary to inject the decomposition treatment agent into the contaminated groundwater. In addition, it is necessary to stir the mixer while stirring the contaminated part such as the water-impermeable layer. The decomposition treatment agent is injected, which is considered to be preferable because the contaminated soil and the decomposition treatment agent are more uniform. However, since the decomposition treatment agent using persulfate is strongly acidic, it is used for corrosion of metals (especially stainless steel) such as a mixer and an injection pipe, and a low-corrosion decomposition treatment agent is urgently required.

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-149083

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2011-173089

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2011-245458

[Patent Document 4] Japanese Patent Publication No. 2000-197899

Therefore, an object of the present invention is to provide a chemical substance decomposition treatment agent composition and a chemical substance decomposition treatment method using the same, which have the effect of suppressing the corrosiveness of the metal and sufficiently decomposing the chemical substance, thereby achieving good balance between the two.

The present inventors have found in order to solve the above problems, and have found a chemical decomposition treatment composition characterized by (A) persulfate, (B) sodium citrate, and (C) selected from alkali metal carbonate. Salts, alkaline earth metal carbonates, and carbonates thereof in the mixture, it is understood that such a composition can achieve the above object, thereby completing the present invention.

According to the present invention, it is possible to provide a chemical substance decomposing agent composition which has a corrosion resistance of a metal and a sufficient chemical decomposition energy in a high-concentration persulfate.

The chemical decomposition agent composition of the present invention comprises: (A) persulfate, (B) sodium citrate, and (C) a carbonate selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates, and mixtures thereof. Composition.

If the chemical substance to be decomposed is an organic substance, the type is not selected. For example, an aliphatic hydrocarbon compound such as hexane or petroleum ether; a benzene ring, toluene, xylene, naphthalene, anthracene, phenanthrene, anthracene, anthracene, etc. may be mentioned. Aromatic hydrocarbon compounds; petroleum products such as kerosene, light oil, heavy oil, gasoline, light oil, lubricating oil, etc.; dichloromethane, chloroform, carbon tetrachloride, monobromotrifluoromethane, monobromochlorodifluoromethane, dibromo Difluoromethane, dibromotetrafluoroethane, tribromofluoromethane, tetrachloroethylene, trichloroethylene, 1,1-dichloroethylene, 1,2-dichloroethylene, vinyl chloride, hexachloroethane, 1, 1,1-trichloroethane, 1,1,2-trichloroethane, 1,1-dichloroethane, 1,2-dichloroethane, 1,2-dichlorotetrafluoroethane, 1 , 3-dichloropropene, 2-chloro-1,3-butadiene. As the alicyclic halide, for example, 1,2,3,4,5,6-hexachlorocyclohexane, adoline (agrochemical), dieldrin, sedrin (agrochemical), chlordane, Heptachlor (insecticide), antler, toxaphene. As the aromatic halide, for example, bis-chlorobenzene trichloroethane (DDT), 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, pentachloro Examples of the organic halide such as phenol, polychlorinated biphenyl (PCB), and dioxin, and the above-mentioned compounds include a cyanide compound such as a cyanide acid free state or a ferricyanide compound. The chemical substance decomposing agent composition of the present invention can be effectively used for an organic halide which is known to be difficult to decompose.

The chemical substance decomposing agent composition of the present invention is used for the purpose of purifying the object to be mixed with the above-mentioned chemical substance. However, as such an object, for example, soil, sludge, factory drainage, and raw can be exemplified. Live drainage, rivers, lakes, groundwater, etc.

<(A) Persulfate>

The persulfate used as the component (A) of the chemical decomposition agent composition of the present invention may, for example, be potassium peroxysulfate, sodium peroxodisulfate or potassium peroxysulfate. Among these, sodium peroxodisulfate and potassium peroxodisulfate are preferred, and sodium persulfate which is economically inexpensive and highly water-soluble is more preferred. The above persulfate may be used singly or in combination of two or more.

<(B) sodium citrate>

"Sodium citrate" is a substance generally represented by Na ₂ O‧nSiO ₂ (wherein, n represents a real number greater than 0) (wherein the value of n is greater than 0). From the viewpoint of obtaining, it is preferable that the value is in the range of n = 0.5 to 4. Specifically, for example, sodium citrate (Na ₂ O ‧ SiO ₂ ‧ x H ₂ O), sodium sesquicarbonate (Na ₂ O‧ 2/3 SiO ₂ ‧ x H ₂ O), sodium metasilicate a powder such as (Na ₂ O‧SiO ₂ ‧xH ₂ O) (wherein x is a number of 0 or more); sodium citrate No. 1 (Na ₂ O‧2SiO ₂ ‧aq), sodium citrate No. 2 (Na ₂ O‧5/2SiO ₂ ‧ aq), sodium citrate No. 3 (Na ₂ O‧3 SiO ₂ ‧ aq), sodium citrate No. 4 (Na ₂ O‧ ₄ SiO ₂ ‧ aq), etc. In the above, the sodium citrate No. 1 to No. 4 refers to the substance specified in JIS K1408.

The sodium citrate (B) which is the component (B) used in the chemical decomposition agent composition of the present invention may be one of a powder or a liquid, but is preferably a liquid which is convenient to use, and specifically, the number 1 can be exemplified. Sodium citrate, Sodium citrate No. 2, sodium citrate No. 3, among which sodium citrate No. 3 which is convenient to use is preferred.

In addition, the details of sodium citrate No. 1 to No. 3 prescribed in JIS K1408 are shown in the following table.

The mixing ratio of the chemical substance decomposing agent composition (A) component and the component (B) to be used in the present invention is not particularly limited, but is 1 part by mass of the component (A) and is SiO ₂ in the component (B). The mass parts are 0.005 to 0.200, the mass parts are preferably 0.008 to 0.180, and the mass parts are preferably 0.008 to 0.150. When the component (B) is less than 0.005 parts by mass, the metal corrosion inhibiting effect may be deteriorated, and when it exceeds 0.200 mass part, the decomposition of the chemical substance may be difficult to progress.

In the chemical decomposition agent composition of the present invention, in addition to the above components (A) and (B), at least one carbonate selected from the group consisting of alkali metal carbonates and alkaline earth metal carbonates is used as (C). )ingredient. (C) is used as a neutralizing agent and helps The stability of sulfate.

<(C1) alkali metal carbonate>

As the alkali metal carbonate (C1), sodium carbonate, sodium hydrogencarbonate, potassium carbonate, potassium hydrogencarbonate or the like can be exemplified.

<(C2) alkaline earth metal carbonate>

As the alkaline earth metal carbonate (C2), magnesium carbonate, calcium carbonate or the like can be exemplified.

The compound used as the component (C) described above is preferably used alone or in combination of two or more.

When the chemical substance decomposer composition of the present invention is used in combination with the component (C), the amount of the component (C) is not particularly limited. However, usually, the component (C) is placed in an amount of 0.01 to 1 with respect to 1 part by mass of the component (A). The mass part is preferably 0.05 to 0.7 parts by mass of the component (C). When the component (C) is less than 0.01 parts by mass, the effect of stabilization may not be obtained, and when it exceeds 1 part by mass, the decomposition of the chemical substance may be difficult to progress. Among the components (C) of the present invention, an alkali metal carbonate (C1) is preferred, and among them, sodium carbonate or sodium hydrogencarbonate is more preferred.

Further, in the chemical substance decomposing agent composition of the present invention, the composition of the component (A), the component (B) and the component (C) may be further added to contain a divalent or trivalent iron ion. (D) ingredient. This component (D) acts as a catalyst for decomposition of chemical substances.

<(D) 2 or 3 iron ions>

The source of the ion of the divalent or trivalent iron ion (D) used in the chemical decomposition agent composition of the present invention is not particularly limited as long as it is soluble in water or dispersible, but iron salt is preferably used. Because of its good solubility in water. As such an iron salt, for example, iron (II) chloride, iron (III) chloride, iron (II) hydrochloride, iron (III) chloride, iron (II) bromide, iron bromide (III) can be exemplified. ), iron (II) iodide, iron (III) iodide, iron (II) nitrate, iron (III) nitrate, iron (II) thiocyanate, iron (III) thiocyanate, iron (II) ), iron (III) oxalate, ammonium (II) sulfate, ammonium (III) sulfate, iron (III) sulfate, iron (II) sulfate, iron (III) sulfate, sodium hexacyanoferrate (II), Potassium ferricyanide, potassium ferrocyanide, potassium ferricyanide, ammonium ferrocyanide, and ferricyanide ammonium.

From the viewpoint of economic efficiency and economical efficiency, iron (II) chloride, iron (III) chloride, iron (II) nitrate, iron (III) nitrate, and iron (II) sulfate are preferred. Iron (III) sulfate, more preferably iron (II) chloride, iron (II) nitrate, iron (II) sulfate, preferably iron (II) chloride, iron (II) sulfate. These iron salts may be anhydrous salt water salts or hydrates, and may be appropriately selected in consideration of solubility in water or ease of dispersion. Further, the hydrate of the present invention is a salt containing crystal water, and for example, a hydrate containing a crystal water and a hydrate containing four crystal water is known, except that iron (II) sulfate is an anhydrous salt. a hydrate containing five crystal waters, a hydrate containing seven crystal waters, and the above iron ions The source may be used alone or in combination of two or more.

When the chemical substance decomposing agent composition of the present invention is used in combination with the component (D), the amount of the component (D) is not particularly limited. Usually, the component (D) is placed in an amount of 0.01 to 1 with respect to 1 part by mass of the component (A). The mass part is preferably 0.05 to 0.7 parts by mass of the component (D), more preferably 0.1 to 0.4 parts by mass of the component (D). When the amount of the component (D) is less than 0.01 parts by mass, the effect of decomposing the chemical substance may not be obtained. When the amount is more than 1 part by mass, the component (A) is consumed in a short period of time and the durability is impaired and the The amount of blending corresponds to the effect.

Further, in the chemical substance decomposing agent composition of the present invention, hydrogen peroxide, a chelating agent, a persulfate stabilizer (excluding the above-described carbonate component (C)), a citric acid gel or the like can be further added.

In the method for treating the decomposition of the chemical substance of the present invention, the chemical substance decomposing agent composition of the present invention (hereinafter referred to as "the present chemical agent") is brought into contact with the soil or water contaminated with the chemical substance, and then the chemical substance is decomposed. The method of processing.

The agent is preferably in the form of an aqueous solution, specifically, an aqueous solution in which the agent is diluted with water to a persulfate of the component (A) in an amount of 1 to 20% by mass, and the amount of the soil is added to the amount of 1 m ^{3 of the} soil to be purified. The aqueous solution is preferably 0.5 to 50 kg of the persulfate of the component (A) which is diluted with water. More preferably 1~40kg, and most preferably 2~20kg. When the persulfate is less than 0.5 kg, the rate of decomposition of the chemical substance will be slow, or the decomposition will be completed. If it exceeds 50 kg, it may have a bad influence on the environment or may not be effective in meeting the added amount. Further, each of the components constituting the present agent can be injected into the soil.

Next, a construction method for purifying soil contaminated with chemical substances will be described. To purify the contaminated soil, you can also dig the contaminated soil, add water to the soil to dissolve it, and then decompose it. You can also directly inject the pesticide into the contaminated soil for decomposition. In this case, it can be applied to single-axis and double-axis auger, or to an excavator such as an excavator with a stirring feather at the front end and a power shovel. Further, it is applicable to a construction method in which a pressure jet machine can be used for drilling, and in addition, it can be exemplified by a combination of a heavy machine similar to the above, or a pumping aeration method. In these construction methods, the heavy opportunity is in contact with the chemical decomposition agent composition.

In the excavation portion of the heavy machine, the piping portion or the like is stainless steel using an alloy containing iron as a main component. The chemical decomposition agent composition of the present invention exhibits low corrosivity without selecting a stainless steel type. For example, carbon steel which is often used as a stainless steel by a heavy machine can be exemplified as carbon steel (JIS G4051) for mechanical construction and profile steel profile (JIS G3101) for general construction. As a specific example, carbon steel for machine structural use: S35C, S45C, S55C, etc., general structural steel profiles: SS400, SS490, SS540, etc. can be exemplified.

[Examples]

Hereinafter, the present invention will be further described based on examples, but the present invention is not limited to the examples. Further, the "part" or "%" in the embodiment is based on the quality standard.

The chemical decomposition agent group of the present invention is carried out according to the following experimental method Metal corrosion of the product and decomposition of the contaminated compound trichloroethylene (TCE).

<Metal rot resistance>

As a test piece of the drug described in Table 1, the weight of the test piece was measured by immersing carbon steel (S45C (JIS G4051); 3.2 × 15 × 30 mm) for mechanical structure at room temperature for 4 days. The results are shown in Table 1. In addition, the number of the composition in the table indicates the mass percentage of the purity of the water of each of the medicaments or the removal of the crystal water. Further, in the item of the weight reduction amount in the table, the amount of reduction is expressed in % with respect to the weight of the test piece before the test.

<Decomposition test>

To 120 ml of the shading micro-bottle, 50 g of the pulverized and dried soil and 50 g of an aqueous solution of TCE 200 mg/l were added. Each of the same chemicals as the metal rot resistance test described above was adjusted to 50 ml with 1.5 ml of ion-exchanged water, and each was added to a light-shielding micro-bottle containing a soil and a TCE aqueous solution. Thereafter, the light-shielding micro-bottle was shaken up and down to homogenize the contents, and allowed to stand in a thermostat at 25 °C. The TCE concentration at this time (before decomposition) was 100 mg/l.

After standing for 4 days, 10 ml of the supernatant liquid in the shading micro-bottle was taken, and the amount of residual TCE was measured by gas chromatography on the basis of JIS K0125. Table 1 shows the results of the TCE concentration. The conditions of gas chromatography are as follows.

<Gas chromatography conditions>

Machine: GC-2014 (made by Shimadzu Corporation)

Column: Inert

Cap1 (inner diameter 0.25 mm, length 30 m, film thickness 1.5 μm; manufactured by GL Scientific Co., Ltd.)

Column temperature: from 40 ° C to 200 ° C (5 ° C / min)

Injection temperature: 200 ° C

Detector temperature: 250 ° C

Injection volume: 0.1ml

Split ratio: 1:50

Further, the content of cerium oxide of No. 3 niobate in Table 1 was 29.10%.

According to the results of the above comparative examples, it was confirmed that the metal rot resistance can be remarkably suppressed by adding the components (B) and (C). Further, it is understood that any of Examples 1 to 5 has a good chemical decomposition energy. Further, the chemical decomposition energy can be further increased by adding the component (D).

Claims (7)

A chemical substance decomposing agent composition comprising: (A) persulfate, (B) sodium citrate, and (C) a carbonic acid selected from the group consisting of alkali metal carbonates, alkaline earth metal carbonates, and the like salt. The chemical substance decomposing agent composition according to claim 1, wherein the (B) sodium citrate is used as the SiO ₂ and the mass part is an aqueous solution of 0.005 to 0.200 with respect to 1 part by mass of the (A) persulfate. . The chemical substance decomposing agent composition according to claim 1 or 2, wherein (A) the persulfate is sodium peroxodisulfate or potassium peroxodisulfate. The chemical substance decomposing agent composition according to any one of claims 1 to 3, further comprising (D) a divalent or trivalent iron ion. The chemical substance decomposing agent composition of claim 4, wherein (D) the ion source of the divalent or trivalent iron ion is iron sulfate. A method for decomposing a chemical substance, characterized in that the chemical substance decomposing agent composition according to any one of claims 1 to 5 is brought into contact with soil or water contaminated with a chemical substance to make the chemical The substance is decomposed. The method for decomposing a chemical substance according to claim 6, wherein the chemical decomposition agent composition is in contact with stainless steel.