KR100495764B1 - Method of preparing iron catalysts for fenton oxidation and use of iron catalysts prepared thereby - Google Patents

Abstract

The present invention is a method for producing an iron catalyst effective in fenton oxidation treatment, phenton oxide, characterized in that the ionic iron is treated with a reducing agent to produce reduced iron and then fired for 2 to 8 hours at a temperature between 100 to 1000 ℃ Provided are a method for preparing an iron catalyst for treatment and an iron catalyst produced thereby. The present invention also provides a method of using the iron catalyst thus prepared for treatment of wastewater or drinking water containing hardly decomposable organic matter.

The Fenton oxidation treatment method using the iron catalyst of the present invention does not generate an iron hydroxide slurry even at pH 5 or higher because the catalyst is not ionic iron, and exhibits excellent waste treatment effect in both acidic, neutral, and alkaline and uses excess hydrogen peroxide. Since it is possible to prevent residual hydrogen peroxide after treatment, it is possible to treat wastewater by the Fenton process, not to generate slurry treatment costs, and to reduce costs by reducing the amount of hydrogen peroxide used and recycling the catalyst due to insoluble water. have.

Description

METHOD OF PREPARING IRON CATALYSTS FOR FENTON OXIDATION AND USE OF IRON CATALYSTS PREPARED THEREBY}

The present invention relates to an improved process for the preparation of iron catalysts useful for fenton oxidation, and to methods for the iron catalysts produced thereby and for the treatment of waste water or drinking water containing hardly decomposable organic matter.

Wastewater containing organic matter is generated in the manufacturing process using various compounds and flows to rivers and seas and is a major factor that inhibits the natural environment. The organic matter contained in the wastewater is very diverse. Basically, organic substance means a substance composed of elements such as carbon, oxygen, nitrogen, hydrogen, and sulfur, and can be classified into three kinds of alkanes, alkenes, and alkynes according to the carbon-to-carbon bond type. Combined to characterize the organics contained in the wastewater. Depending on the form of the functional group, the organic matter contained in the waste water is classified into aldehyde, nitrile, alcohol, amine, amide, aromatic, acid, and the like.

As such, since the types of organic matter contained in the wastewater are very diverse, it is very difficult to treat the wastewater.

Wastewater containing nitrogen-containing compounds, such as amine compounds, amide compounds, amino acid compounds, etc., in the wastewater is flocculated using an anionic polymer coagulant, but subsequent treatment is necessary because the sludge is released. In addition, even when the adsorption method is used, it is difficult because the efficiency of the adsorbent is lowered due to the amine.

In the case of wastewater containing sulfur compounds, it is common to treat one or both of biological treatment and softening. In the case of the biological treatment, it is necessary to dilute the wastewater solution so that the organism is not adversely affected, and the combustion method requires a separate fuel, and since sulfuric acid is contained in the wastewater in a large amount, a desulfurization device is required.

In the case of wastewater containing organic halogen compounds, organic halogen compounds are difficult to decompose, so they accumulate severely in the natural environment, and as a result, groundwater contamination appears in many places. Moreover, organic halogen compounds have been found to be carcinogens, and trichloroethylene, tetrachloroethylene, 1,1,1-trichloroethane and the like have been designated as regulated items of the Water Pollution Prevention Act. Methods of treating wastewater containing organic halogen compounds include evaporation and adsorption, but it is difficult to prevent fundamental environmental pollution or an adsorbent treatment.

Known methods for treating hardly decomposable organic matter include biological and chemical methods called activated sludge methods. Activated sludge takes a long time to decompose organic compounds and the wastewater must be diluted to a concentration suitable for the growth of algae and bacteria. Therefore, this method has a disadvantage in that a large space is required to prepare a treatment facility, and wastewater containing aromatic organic matter, which is a hardly decomposable substance, is discharged without being decomposed due to shock or poor treatment.

Currently, the most commonly used chemical treatment methods include iron oxidation, ozone oxidation, and Fenton oxidation.

The iron oxidation method uses simple oxidation and agglomeration using ferrous iron and ferric iron, which is inexpensive, easy to process, and excellent in coagulation, but poor in processing efficiency.

Recently, ozone oxidation method is widely used for drinking water treatment, which has high treatment cost and concerns about secondary pollution to ozone agent, and it is necessary to adsorb and treat the gas generated after ozone treatment with activated charcoal, and complicated equipment of ozone generator. However, it is not suitable for the treatment efficiency of wastewater containing various organic substances.

Fenton oxidation is a reaction published by HJH Fenton in 1894 that oxidizes organic matter using hydrogen peroxide and divalent iron ions. Specifically, hydrogen peroxide water is used as a catalyst for iron salts such as FeSO ₄ , Fe ₂ (SO ₄ ) ₃ , FeCl ₂ , FeCl ₃ to generate free radicals (OH) having strong oxidizing power to decompose organic matter remaining in the waste water. Way. This method has been shown to be relatively excellent in processing efficiency, but has a problem in that a large amount of sludge in the form of iron hydroxide due to the iron used as a catalyst of the reaction.

In addition, high temperature, high pressure, ultraviolet, ozone, and oxidation using hydrogen peroxide are known, but are only used in wastewater having a COD concentration of 100 ppm or less, and thus are not suitable as a method for treating wastewater.

The inventors of the present invention show that the wastewater treatment efficiency is relatively excellent among the various chemical treatment methods described above, and in recent years, attempts to apply industrial wastewater treatment have been relatively actively studied, and biologically degradable substances are converted into biodegradable substances or toxic. The purpose of the present invention is to improve the fenton oxidation method, which is also diversified, which reduces the toxicity of waste water, which has an adverse effect on microorganisms, and the post-treatment of the polishing concept of treating substances not treated by microorganisms after biological treatment. We are making continuous research efforts.

As a result of this research effort, by improving the catalyst used in the fenton oxidation method, it is possible to solve the above-mentioned problems of the fenton oxidation method and to obtain a wastewater treatment method exhibiting an extremely high decomposition efficiency of organic matter.

The present inventors have already disclosed a metal oxide catalyst for photophentone oxidation, a method for preparing the same, and a method for treating hardly decomposable organic substances using the same through Korean Patent Application No. 99-54742, which is co-pending. This application proposes a method for producing a metal, a metal oxide, a metal carbonate or a metal hydroxide, which is calcined at 100 to 1500 ° C. under an air, oxygen, hydrogen or nitrogen atmosphere.

The present inventors have been able to produce the iron catalyst for fenton oxidation by a method different from the method described in the above-described application, and found that the catalyst has excellent organic decomposition efficiency, thus completing the present invention.

The present invention solves all the problems in wastewater treatment by the Fenton oxidation method described above, and effectively decomposes organic compounds containing aromatics, which are hardly decomposable substances, as well as wastewater containing nitrogen, sulfur, and organic halogen compounds. When the treatment is to provide a catalyst for activating the activity of the microorganism and its production method, and a method for treating waste water or drinking water using the catalyst with high efficiency.

The present invention is to prepare the iron catalyst for fenton oxidation treatment, characterized in that the ionic iron is treated with a reducing agent in the first embodiment to produce reduced iron and then calcined for about 2 to 8 hours at a temperature between about 100 to 1000 ℃ Provide a method.

In this embodiment, the ionic iron is selected from the group consisting of iron acetate, iron sulfate, iron ammonium, iron hydrochloride, iron carbonate, iron bromide, iron fluoride, iron iodide, iron nitrate, iron oxalate, iron phosphate, respectively, or a mixture of two or more thereof. Can be used as Ionic iron is dissolved in water and made into a solution before treatment with a reducing agent.

As a preferable specific example of this manufacturing method, a hydrazine, a borohydride salt, etc. can be used as a reducing agent.

As another preferred embodiment of this manufacturing method, firing can be carried out using an electric furnace.

The present invention provides, in a second aspect, an iron catalyst for fenton oxidation treatment prepared by the above-described manufacturing method.

Iron catalyst of the present invention is insoluble in water, there is an advantage that can be recycled without causing sludge problems. In addition, when manufactured using two or more kinds of ionic iron, the prepared iron catalyst has an oxidation number of 0, di and trivalent mixed according to the type of starting material, such 0, divalent and trivalent The mixed iron catalyst reacts well with hydrogen peroxide solution to cause oxidation reaction, so it can be used as a catalyst for Fenton reaction with good efficiency.

The present invention provides a method of using the iron catalyst for fenton oxidation treatment described above in a third embodiment for treating wastewater containing hardly decomposable organic substances.

In addition, the present invention provides a method of using the above-described iron catalyst for fenton oxidation treatment in drinking water treatment as a fourth aspect.

The main purpose of the Fenton treatment is to completely oxidize particularly organic substances present in the wastewater to reduce the pollutant load or to convert high concentrations of hardly decomposable organic substances to facilitate microbial degradation.

The conventional Fenton oxidation method generates OH radicals using hydrogen peroxide and iron salts, the Fenton's reagent, to decompose organic matters with the strong oxidizing power of the Fenton's reagent. Three steps, such as oxidation reaction by the Fenton's reagent, neutralization and coagulation process to remove iron salt Can be divided into:

This fenton oxidation method oxidizes organic matter by the following mechanism.

As shown in the oxidation mechanism, the conventional Fenton oxidation method generates OH radicals while oxidizing Fe ^{2+ to} Fe ³⁺ by hydrogen peroxide solution, and the oxidation reaction proceeds by the OH radicals. In this reaction, Fe ³⁺ must be reduced back to Fe ²⁺ by hydrogen peroxide to continue the phentone oxidation reaction. Since the rate of iron oxidation is faster than the rate of reduction, trivalent iron accumulates, thereby reducing the reaction efficiency. do. Finally, the reaction no longer proceeds. These less effective catalysts should be removed after making them insoluble iron hydroxide by increasing the pH using caustic soda. In this process, a large amount of iron sludge to be generated is generated.

However, in the present invention, since the iron catalyst insoluble in water is used for wastewater treatment, the problem of iron slurry does not occur, and the catalyst can be reused.

In addition, the conventional Fenton oxidation method should be added to the iron ion concentration of approximately 5000 ppm or more, and the amount of hydrogen peroxide should be added about twice the iron ion, about 10000 ppm of hydrogen peroxide water should be entered. Therefore, after the phenton oxidation occurs, the iron ions become iron hydroxide when it is neutralized using caustic soda, so that there is a sludge problem, and there is a problem that the excess hydrogen peroxide solution to react without reacting.

On the other hand, the iron catalyst of the present invention can be about 1000 ppm and the amount of hydrogen peroxide can be 400 ppm, so that all of the hydrogen peroxide is consumed in the reaction, so there is no problem of residual hydrogen peroxide.

PH is important for fenton oxidation. In the conventional Fenton oxidation method, since the reaction proceeds only when the pH is maintained between 3 and 4, a problem of corrosion of the reaction tank occurs, and an alkali agent such as sodium hydroxide should be used since the pH must be adjusted to neutral again after the reaction. When the pH is increased to 5 or more, iron ions used as catalysts form iron hydroxides, which are known to no longer participate in the Fenton reaction.

In contrast, the iron catalyst prepared in the present invention does not form iron hydroxide even though the pH is 5 or more because it is not iron ion. In addition, the iron catalyst of the present invention reacts well in both acidic, neutral and alkaline, and since most wastewater is about acidic pH = 6, there is no need to artificially manipulate the pH so that the pH of the tank after neutralization or neutralization is neutral. You don't have to do anything artificial to make it work.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

(Example 1)

100 g of ferric sulfate was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, followed by precipitation to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 2)

The iron catalyst of the present invention was prepared in the same manner as in Example 1 except that the product was calcined at 400 ° C. for 3 hours.

(Example 3)

The iron catalyst of the present invention was prepared in the same manner as in Example 1 except that the product was calcined at 800 ° C. for 3 hours.

In order to measure the oxidation state of the iron catalyst prepared as described in Examples 1 to 3, it was analyzed by X-ray photoelectron spectroscopy. The result is as shown in FIG. In Figure 1, A is the iron catalyst of the present invention obtained in Example 2, B is the iron catalyst of the present invention obtained in Example 1 and C is the iron catalyst of the present invention obtained in Example 3 measured by an X-ray photoelectron spectrometer D is a result of measuring iron (magnetite) with an X-ray photoelectron spectrometer in a comparative group. From this result, it was found that the iron catalyst of the present invention is in an oxidation state different from that of conventional iron.

(Example 4)

100 g of iron acetate was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, followed by precipitation to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 5)

100 g of iron ammonium was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, followed by precipitation to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 6)

100 g of iron hydrochloride was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 7)

100 g of iron carbonate was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 8)

100 g of iron bromide was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, followed by precipitation to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 9)

100 g of fluorine iron was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, followed by precipitation to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at a temperature of 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 10)

100 g of iron iodide was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 11)

100 g of iron nitrate was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 12)

100 g of iron oxalate was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 13)

100 g of iron phosphate was dissolved in 1 L of water, and then 10 g of hydrazine was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 14)

After dissolving 100 g of iron acetate in 1 L of water, 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 15)

100 g of ferric sulfate was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 16)

100 g of ammonium iron was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 17)

100 g of iron hydrochloride was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 18)

100 g of iron carbonate was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 19)

100 g of iron bromide was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 20)

After dissolving 100 g of iron fluoride in 1 L of water, 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 21)

100 g of iron iodide was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 22)

100 g of iron nitrate was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 23)

100 g of iron oxalate was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

(Example 24)

100 g of iron phosphate was dissolved in 1 L of water, and then 10 g of borohydride salt was added to the solution to reduce iron, and then precipitated to obtain solid reduced iron. The reduced iron thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron catalyst.

Hereinafter, in order to test and evaluate the degradability of the organic catalyst of the iron catalyst of the present invention, the phenol decomposition rate and the hydrogen peroxide decomposition rate were measured by adding phenol and the iron catalyst of the present invention as the hardly degradable organic material to the synthetic wastewater. In the comparison group, the experiment was performed using iron sulfate, which is used as a catalyst in the conventional Fenton oxidation method, and goethite, hematite, magnetite, and iron oxide.

(Processing example 1)

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 3, 0.1 g of iron catalyst obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. I was. After reaction at room temperature for 10 minutes, phenol was decomposed more than 99%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that the hydrogen peroxide water was decomposed more than 99% after 40 minutes (see FIG. 2).

Comparative Example 1

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 3, and then 0.0035 g of iron sulfate, which is frequently used as a catalyst in the conventional Fenton oxidation method, was added. 0.1 mL was added and reacted. After reaction at room temperature for 10 minutes, phenol was decomposed more than 99%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that the hydrogen peroxide water was decomposed more than 99% after 40 minutes (see Fig. 3).

Comparative Example 2

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly degradable organic substance, adjust pH to 3, add 0.1 g of goethite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. I was. After 10 minutes of reaction at room temperature, phenol was decomposed about 10%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 80% of hydrogen peroxide water remained after 40 minutes (see Fig. 4).

Comparative Example 3

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, adjust pH to 3, add 0.1 g of hematite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. I was. After reacting for 10 minutes at room temperature, phenol decomposed about 15%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 70% of the hydrogen peroxide water remained after 40 minutes (see Fig. 4).

Comparative Example 4

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly degradable organic substance, adjust pH to 3, add 0.1 g of magnetite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. I was. After reaction at room temperature for 10 minutes, phenol decomposed about 35%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that after 40 minutes, the hydrogen peroxide water remained more than 60% (see Fig. 4).

(Process Example 2)

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 5, 0.1 g of iron catalyst obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. I was. After reaction at room temperature for 10 minutes, phenol was decomposed more than 99%. In addition, as a result of checking the residual amount of hydrogen peroxide after the reaction, it was confirmed that the hydrogen peroxide water was decomposed by 99% or more after 5 minutes (see FIG. 2).

Comparative Example 5

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, adjust pH to 5, and then add 0.0035g of iron sulfate which is used as a catalyst in the conventional Fenton oxidation method, and 35% hydrogen peroxide 0.1 After adding mL, the reaction was carried out. After 40 minutes of reaction at room temperature, phenol was hardly decomposed. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that hydrogen peroxide water was hardly decomposed even after 40 minutes (see FIG. 3).

(Process 3)

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 7. Then, 0.1 g of the iron catalyst obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. I was. After reaction at room temperature for 10 minutes, phenol was decomposed more than 99%. In addition, as a result of checking the residual amount of hydrogen peroxide after the reaction, it was confirmed that the hydrogen peroxide water was decomposed by 99% or more after 5 minutes (see FIG. 2).

Comparative Example 6

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 7. Then, 0.0035 g of iron sulfate, which is used as a catalyst in the conventional Fenton oxidation method, was added, and 35% hydrogen peroxide 0.1. After adding mL, the reaction was carried out. After 40 minutes of reaction at room temperature, phenol was hardly decomposed. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that hydrogen peroxide water was hardly decomposed even after 40 minutes (see FIG. 3).

(Processing Example 4)

PH was adjusted to 9 by adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, and then 0.1 g of the iron catalyst obtained in Example 1 was added and 0.1 mL of 35% hydrogen peroxide solution was added. I was. After reaction at room temperature for 10 minutes, phenol was decomposed more than 99%. In addition, as a result of checking the residual amount of hydrogen peroxide after the reaction, it was confirmed that the hydrogen peroxide water was decomposed by 99% or more after 5 minutes (see FIG. 2).

Comparative Example 7

After adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 9, and then 0.0035 g of iron sulfate, which is used as a catalyst in the conventional Fenton oxidation method, was added, and 35% hydrogen peroxide 0.1. After adding mL, the reaction was carried out. After 40 minutes of reaction at room temperature, phenol was hardly decomposed. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that hydrogen peroxide water was hardly decomposed even after 40 minutes (see FIG. 3).

(Process 5)

PH was adjusted to 11 by adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, and 0.1 g of the iron catalyst obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. I was. After reaction at room temperature for 10 minutes, phenol was decomposed more than 99%. In addition, as a result of checking the residual amount of hydrogen peroxide after the reaction, it was confirmed that the hydrogen peroxide water was decomposed by 99% or more after 5 minutes (see FIG. 2).

Comparative Example 8

PH was adjusted to 11 by adding acid to 100 mL of synthetic wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, and then 0.0035 g of iron sulfate, which is used as a catalyst in the conventional Fenton oxidation method, was added, and 35% hydrogen peroxide 0.1. After adding mL, the reaction was carried out. After 40 minutes of reaction at room temperature, phenol was hardly decomposed. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that hydrogen peroxide water was hardly decomposed even after 40 minutes (see FIG. 3).

As described above, the iron catalyst of the present invention exhibits excellent decomposition rate of hardly decomposable organic matters compared to conventional iron oxide regardless of acidic, neutral and alkaline conditions. The different oxidation state represented by the iron catalyst of the present invention works in favor of the Fenton treatment method. I could see that.

Wastewater treatment method using the iron catalyst prepared by the production method of the present invention is applied to the conventional Fenton process by fundamentally removing the iron slurry generated after the limitation of acid conditions and the treatment pointed out as a disadvantage of the conventional Fenton process It can be applied in difficult workplaces, drastically reduce the amount of chemicals and waste water used to create acid conditions and discharge to neutral again, and it does not incur slurry processing costs because no slurry is generated. Significantly reduce costs

The iron catalyst of the present invention can be applied to wastewater treatment in a wastewater treatment plant to which the Fenton treatment method is applied, and the conventional Fenton treatment method is difficult to apply due to the remaining hydrogen peroxide problem when applied to drinking water, but this treatment method has no residual hydrogen peroxide solution and iron. It does not dissolve in water, so it can be applied to the treatment of drinking water. It can be applied to all workplaces using the existing Fenton treatment method, and the overall cost is reduced compared to the existing Fenton treatment process. Therefore, it is considered to be very marketable in the wastewater treatment market or the drinking water treatment market.

1 is a comparative measured XPS (X-ray photoelectron spectroscopy) graph showing different oxidation states of iron catalysts obtained according to the production method of the present invention and conventional iron (magnetite).

Figure 2 is a result of fenton oxidation treatment of phenol using the iron catalyst prepared according to the present invention.

Figure 3 is a result of fenton oxidation treatment of phenol using iron sulfate commonly used in the conventional Fenton treatment method.

4 is a result of fenton oxidation of phenol using conventional iron oxides.

Claims (7)

After reducing the ionic iron with a reducing agent to produce a reduced iron, it is calcined for 2 to 8 hours at a temperature between 100 to 1000 ° C. The sole ionic iron according to claim 1, wherein the ionic iron is selected from the group consisting of iron acetate, ferrous sulfate and ferric sulfate, iron ammonium, iron hydrochloride, iron carbonate, iron bromide, iron fluoride, iron iodide, iron nitrate, iron oxalate, and iron phosphate Method for producing an iron catalyst for fenton oxidation treatment, characterized in that water or a mixture of two or more. The method of claim 1, wherein the reducing agent comprises one selected from hydrazine and borohydride salts. An iron catalyst for fenton oxidation treatment produced according to any one of claims 1 to 3. The method for using the iron catalyst for fenton oxidation treatment of Claim 4 for wastewater treatment containing hardly decomposable organic substance. 6. The method of claim 5 wherein the hardly degradable organics comprise organic compounds containing nitrogen, sulfur, organohalogen compounds and aromatics. The iron catalyst for fenton oxidation treatment of Claim 4 used for drinking water treatment.