KR20070112918A - The elution inhibitor of the pollutant in the fly ash - Google Patents

Abstract

A noble elution-preventing agent of contaminants is provided to exhibit a function of effectively preventing the contaminants from being eluted by blending the elution-preventing agent with contaminated soil or fly ash, thereby immobilizing contaminants contained in the contaminated soil or fly ash. An elution-preventing agent of contaminants comprises aluminum sulfate, sodium thiosulfate, and iron as essential components. The elution-preventing agent of contaminants comprises 100 weight parts of aluminum sulfate, 20 to 500 weight parts of sodium thiosulfate, and 20 to 300 weight parts of iron. The elution-preventing agent of contaminants further comprises at least one selected from the group consisting of magnesium oxide, activated carbon, silica gel, quicklime, and zeolite.

Description

Elution Inhibitor of Fly Ash in Fly Ash {THE ELUTION INHIBITOR OF THE POLLUTANT IN THE FLY ASH}

The present invention relates to an agent for preventing the leaching of pollutants, and more specifically, for example, soil pollutants such as those listed in the Ministry of Environment Notification No. 46 (hereinafter referred to as environmental standard) on August 23, 3 The present invention relates to an elution inhibitor for pollutants that can effectively prevent elution.

Wastes such as industrial waste, sewage sludge, and household waste contain various kinds of pollutants. If these materials are disposed of as they are, the pollutants are eluted by rainwater, causing serious environmental pollution such as soil pollution or water pollution. For this reason, measures have been adopted such that these wastes are once solidified with cement or the like, then disposed of, or incinerated to be recycled, for example, cement solidified and disposed of.

However, even if the above treatment is carried out, there is a problem that, for example, the contaminants (mainly heavy metal components) contained in the incineration ashes also elute with time. As for the problem of environmental pollution, the types of pollutants are opened in accordance with the above-mentioned environmental standards (targeted for soil), and their elution allowances are determined, and standards for soil that do not meet these environmental standards are as soon as possible. Efforts have been made to achieve and maintain

Considering this, for example, a drug that can be prevented from leaching contaminants in the contaminated soil by mixing with contaminated soil is useful for preventing the spread of environmental pollution. It is becoming.

The present invention is a drug developed in response to the above-mentioned requirements, and when used in blends with contaminated soil or incineration, for example, it insolubilizes the contaminants contained in them and exhibits a function of effectively preventing elution. The aim is to provide new release agents for contaminants.

In order to achieve the above object, in the present invention, an anti-elution agent for pollutants comprising aluminum sulfate, titanium thiosulfate and iron as essential components is provided.

The leaching inhibitor of the present invention contains aluminum sulfate, sodium thiosulfate and iron as essential components. When aluminum sulfate coexists, it dissolves in the water and functions as an electrolyte. In the process of hydrolysis, aluminum hydroxide forms polycondensation ions as a polymer, and condenses by contaminating the contaminants therein. It is thought to act to insolubilize pollutants.

Sodium thiosulfate has a dechlorination effect, for example PCB, dichloromethane, carbon tetrachloride, 1, 2-dichloroethane, 1, 1-dichloroethylene, cis-1, 2-dichloroethylene, 1, 1, 1- Contributes to insolubilization (detoxification) of chlorine-containing contaminants such as trichloroethane, 1, 1, 2-trichloroethane, trichloroethylene, tetrachloroethylene, 1, 3-dichloropropene. In addition, sodium thiosulfate is decomposed into constituents of Na, S, and O _{2 in} the presence of water, and the components are insoluble (unharmed) by combining these components alone or in combination with contaminants.

When the compounding quantity of this sodium thiosulfate is too small, the said effect is not fully exhibited. On the contrary, when too much sodium sulphate is added, the relative amount of the said aluminum sulfate and iron mentioned later will decrease, and the expression of these effects will be attenuated. It is preferable to set the compounding quantity of sodium thiosulfate to 20-500 weight part with respect to 100 weight part of aluminum sulfate in such a thing.

Iron itself is oxidized to decompose contaminants by acting as an oxidizing agent and detoxifies them, and in combination with and insolubilizes contaminants by catalysis of sodium thiosulfate. In particular, when the pollutant is a hexavalent chromium component, it binds to it and stabilizes it to prevent re-dissolution. As such iron powder, RDL-300 (brand name, Powder Tech Co., Ltd. product) etc. are mentioned, for example.

If the amount of iron is too small, the above-mentioned effects are not sufficiently exhibited. On the other hand, if the amount is too high, the relative amount of other essential ingredients decreases, and the expression of the effects thereof is reduced. It is preferable to set it as 20-300 weight part. In addition, iron powder here means the thing of the powder containing Fe component.

The dissolution inhibitor of the present invention is composed essentially of the three components described above. Depending on the type and amount of contaminants, the following materials may be further blended. For example, it is most suitable to mix zeolite or pineapple enzyme for insolubilization of PCB, cadmium and dioxin, and activated carbon, silica gel, quicklime or zeolite can be blended for fluorine and boron.

The leaching inhibitor of the present invention is mixed with the object to be treated such as contaminated soil and used for practical use. In this case, the amount of the pollutant in the object to be treated varies depending on the amount and type of the pollutant. However, the dissolution inhibitor may be mixed in an amount of about 0.2 to 10 parts by weight based on 100 parts by weight of the object.

(Example 1)

Three kinds of fly ashes A, B, and C were prepared. On the other hand, the following three kinds of solvents a, b, and c were prepared.

a: 49.2 mL of glacial acetic acid and 14.8 g of anhydrous sodium acetate were dissolved in distilled water to make 1 L, and it was pH 4 using 1N acetic acid or 1N sodium hydroxide aqueous solution.

b: Prepared in the manner prescribed by Environmental Office Notice No. 46 (August 23, 2012).

c: 27.5 mL of 1 mol / L aqueous sodium carbonate solution and 22.5 mL of 1 mol / L sodium hydrogencarbonate aqueous solution were mixed, it was made into 1L with distilled water, and it was set to pH10 using 1N sodium hydroxide aqueous solution or 1N aqueous hydrochloric acid solution.

A mixture of fly ash A and solvent a, fly ash B and solvent b, fly ash C and solvent c was prepared to prepare a sample solution by the method specified in the above-mentioned Environmental Agency Notification No. 46, and the analysis method shown in Table 1 for the sample solution. Pollutants were quantified. The results are shown in Table 1.

TABLE 1

On the other hand, 100 parts by weight of sodium thiosulfate and 100 parts by weight of RDL-300 (iron powder) were uniformly mixed with respect to 100 parts by weight of aluminum sulfate to prepare an elution inhibitor. And 1 weight part of said elution inhibitor was mixed with respect to 100 weight part of each fly ash A, B, and C, and it was set as three new types of object A ', B', and C '.

Subsequently, sample liquids were prepared for these treated objects A ', B' and C 'in the same manner as in the case of fly ash A, B and C, and the contaminants were quantified. The results are shown in Table 2.

TABLE 2

In contrast to Table 1 and Table 2, the following is clear.

(1) First, as is evident in the cases of fly ashes A and B, the use of the eluting release agent of the present invention reliably suppresses the dissolution of hexavalent chromium to an extent that satisfies the environmental standard value. Although arsenic does not satisfy the environmental standard (in the case of fly ash A), the amount of elution is obviously lowered.

(2) Interestingly, the use of the elution inhibitor of the present invention suppresses the elution of fluorine and boron. This dissolution inhibitor is considered to be effective not only for soil environmental standards but also for standards related to water pollution.

(Example 2)

Dissolution test according to No. 47, No. 47 of Soil, about soil of a field, and JIS K010255. The eluted cadmium was quantified by applying the frame atomic absorption method specified in 2. The cadmium analysis value was 3. 6 mg / kg.

Subsequently, 1 part by weight of the elution inhibitor used in Example 1 was mixed with 100 parts by weight of soil of the field, and the mixture was subjected to the above test to analyze the elution cadmium. The result was 0.2 mg / kg. As is apparent from this, the dissolution preventing agent of the present invention effectively prevents dissolution of cadmium.

As is apparent from the above description, the elution inhibitor of the present invention can be used by mixing in contaminated soil, for example, insolubilizing contaminants contained in the soil to prevent elution. In preventing the spread of pollution and preserving the environment, its industrial value is very large.

Claims (3)

An anti-elution agent for pollutants, comprising aluminum sulfate, sodium thiosulfate and iron as essential components. The method of claim 1, 20 to 500 parts by weight of sodium thiosulfate and 20 to 300 parts by weight of iron based on 100 parts by weight of the aluminum sulfate. The method according to claim 1 or 2, At least one kind selected from the group consisting of magnesium oxide, activated carbon, silica gel, quicklime and zeolite is further included.