KR100495765B1 - Method of preparing iron oxide catalysts for fenton oxidation and use of iron oxide catalysts prepared thereby - Google Patents

Abstract

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

The Fenton oxidation treatment method using the iron oxide 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 an excellent waste treatment effect not only in acidic conditions but also in neutral conditions and using 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 such as reduction of hydrogen peroxide usage and catalyst recycling due to insoluble water. Can be.

Description

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

The present invention relates to an improved process for the production of iron oxide catalysts useful for fenton oxidation, and to methods for producing iron oxide catalysts and their use in fenton oxidation 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 the biological treatment and the combustion method in parallel. 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 oxide catalyst for fenton oxidation by a method different from the method described in the above-mentioned 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 provides a method for producing an iron oxide catalyst for fenton oxidation, which is characterized in that the iron is prepared by treating ionic iron with an alkali agent in a first embodiment and then calcining at a temperature between about 100 to 1000 ° C. for 2 to 8 hours. to provide.

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

As a preferable specific example of this production method, caustic soda, potassium hydroxide, ammonia and the like can be used for the alkali treatment. It is preferable that pH of this alkali chemicals is the range of pH 8-10. Preferably, the alkali agent is pH 9.

As a particularly preferred embodiment of this manufacturing method, the firing is preferably carried out for 3 hours at a temperature of 600 ℃ using an electric furnace.

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

Iron oxide 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 produced iron oxide has an oxidation number mixed with divalent and trivalent, depending on the type of starting material. The mixed iron oxides such as divalent and trivalent react well with hydrogen peroxide to cause oxidation, and thus can be used as catalysts for Fenton reaction having good efficiency.

The present invention provides a method of using the above-described iron oxide catalyst for fenton oxidation treatment to treat wastewater containing hardly decomposable organic substances.

The present invention also provides a method of using the above-described iron oxide catalyst for fenton oxidation treatment to treat drinking water.

The main purpose of the Fenton treatment is to completely oxidize contaminants, especially organic substances, present in the waste water to reduce the pollutant load, or to convert high concentration hardly degradable organic substances to facilitate microbial decomposition.

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 iron oxide 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 oxide 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 solution.

PH is important for fenton oxidation. In the conventional Fenton oxidation method, since the reaction proceeds only when the pH is maintained between 2 and 4, the problem of corrosion of the reaction tank occurs, and an alkaline agent such as sodium hydroxide was used because the pH should 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 oxide 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 oxide catalyst of the present invention reacts well in both neutral and acidic conditions, and since most wastewaters have a weak acidity of pH = 6, there is no need to artificially manipulate the pH, so that the pH of the tank is neutral after corrosion or reaction. There is no need for artificial manipulation.

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 iron acetate was dissolved in 1 L of water, and 4 g of caustic soda was added to the solution to prepare iron hydroxide, which was then precipitated to obtain solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

In order to measure the oxidation state of the iron oxide catalyst thus prepared, it was analyzed by X-ray photoelectron spectroscopy. The result is as shown in FIG. As a comparative group, the results obtained by X-ray photoelectron spectroscopy of iron sulfate (b) and iron oxide (c), hematite (d), and magnetite (e), which are widely used in the conventional Fenton oxidation method, are shown. From this result, it was found that the iron oxide catalyst of the present invention exhibits an oxidation state different from that of any existing iron oxide.

(Example 2)

100 g of ferrous sulfate was dissolved in 1 L of water, and 4 g of caustic soda was added to the solution to prepare iron hydroxide, which was then precipitated to obtain a solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 3)

100 g of iron ammonium was dissolved in 1 L of water, and then 4 g of caustic soda was added to the solution to prepare iron hydroxide, followed by precipitation to obtain solid iron hydroxide. The iron hydroxide thus obtained was dried and then fired at a temperature between 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 4)

After dissolving 100 g of iron hydrochloride in 1 L of water, 4 g of caustic soda was added to the solution to prepare iron hydroxide, and then precipitated to obtain a solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 5)

After dissolving 100 g of iron carbonate in 1 L of water, 4 g of caustic soda was added to the solution to prepare iron hydroxide, and then precipitated to obtain solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 6)

100 g of iron bromide was dissolved in 1 L of water, and 4 g of caustic soda was added to the solution to prepare iron hydroxide, followed by precipitation to obtain solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 7)

After dissolving 100 g of iron fluoride in 1 L of water, 4 g of caustic soda was added to the solution to prepare iron hydroxide, and then precipitated to obtain a solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 8)

100 g of iron iodide was dissolved in 1 L of water, and 4 g of caustic soda was added to the solution to prepare iron hydroxide, followed by precipitation to obtain solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 9)

After dissolving 100 g of iron nitrate in 1 L of water, 4 g of caustic soda was added to the solution to prepare iron hydroxide, and then precipitated to obtain a solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 10)

After dissolving 100 g of iron oxalate in 1 L of water, 4 g of caustic soda was added to the solution to prepare iron hydroxide, and then precipitated to obtain a solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

(Example 11)

After dissolving 100 g of iron phosphate in 1 L of water, 4 g of caustic soda was added to the solution to prepare iron hydroxide, and then precipitated to obtain a solid iron hydroxide. The iron hydroxide thus obtained was dried and calcined at 600 ° C. for 3 hours using an electric furnace to prepare an iron oxide catalyst.

Hereinafter, in order to test-evaluate the degradability of the organic oxides of the iron oxide catalyst of the present invention, phenol, 4-chlorophenol or 2-chlorophenol and the iron oxide catalyst of the present invention are added to the synthetic wastewater to reduce the phenol decomposition rate and the hydrogen peroxide decomposition rate. Measured. The comparative group was experimented with iron sulfate widely used in the conventional Fenton oxidation method and goethite, hematite, magnetite and iron oxide.

(Processing example 1)

PH was adjusted to 3 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 catalyst (iron oxide) obtained in Example 1 was added and 0.1 mL of 35% hydrogen peroxide solution was added thereto. The reaction was carried out. After reaction at room temperature for 15 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 wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, adjust pH to 3, and then add 0.0035 g of iron sulfate, which is used as a catalyst in the conventional Fenton oxidation method, and 0.1 mL of 35% hydrogen peroxide solution. After the reaction was carried out. After reaction at room temperature for 15 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 wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 3, 0.1 g of goethite, one of the existing iron oxides was added, and 0.1 mL of 35% hydrogen peroxide solution was added. . After reaction at room temperature for 15 minutes, 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 50% of hydrogen peroxide water remained after 40 minutes (see Fig. 4).

Comparative Example 3

After adding acid to 100 mL of wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 3, 0.1 g of hematite, one of the existing iron oxides was added, and 0.1 mL of 35% hydrogen peroxide solution was added. . The reaction was carried out at room temperature for 15 minutes, resulting in about 40% degradation of phenol. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 50% of hydrogen peroxide water remained after 40 minutes (see Fig. 4).

Comparative Example 4

After adding acid to 100 mL of wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, pH was adjusted to 3, 0.1 g of magnetite, one of the existing iron oxides was added, and 0.1 mL of 35% hydrogen peroxide solution was added. . After 15 minutes of reaction at room temperature, phenol decomposed about 45%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 50% of hydrogen peroxide water remained after 40 minutes (see Fig. 4).

(Process Example 2)

PH was adjusted to 3 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, a hardly decomposable organic substance, and 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. After the reaction was carried out. After 5 minutes of reaction at room temperature, 4-chlorophenol 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 30 minutes (see FIG. 5).

Comparative Example 5

PH was adjusted to 3 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, which is a hardly decomposable organic substance. Then, 0.0035 g of iron sulfate, which is frequently used as a catalyst in the conventional Fenton oxidation method, was added, followed by 35% hydrogen peroxide. 0.1 mL of water was added and reacted. After 5 minutes of reaction at room temperature, 4-chlorophenol 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 about 90% after 40 minutes (see FIG. 6).

Comparative Example 6

After adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol which is a hardly decomposable 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. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol was decomposed about 60%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that 40% or more of hydrogen peroxide water remained after 40 minutes (see FIG. 7).

Comparative Example 7

After adding acid to 100 mL of waste water containing 200 ppm of 4-chlorophenol 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. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol decomposed about 50%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 50% of hydrogen peroxide water remained after 40 minutes (see Fig. 7).

Comparative Example 8

After adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol which is a hardly decomposable 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. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol decomposed about 50%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 50% of hydrogen peroxide water remained after 40 minutes (see Fig. 7).

(Process 3)

PH was adjusted to 3 by adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, a hardly decomposable organic substance, and then 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added and 0.1 mL of 35% hydrogen peroxide solution was added. After the reaction was carried out. After 5 minutes of reaction at room temperature, 2-chlorophenol 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 30 minutes (see FIG. 8).

Comparative Example 9

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol 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, followed by 35% hydrogen peroxide. 0.1 mL of water was added and reacted. After 5 minutes of reaction at room temperature, 2-chlorophenol 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 about 90% after 30 minutes (see Fig. 9).

Comparative Example 10

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable 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. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol decomposed about 40%. 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. 10).

Comparative Example 11

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol 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. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol decomposed about 40%. 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. 10).

Comparative Example 12

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable 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. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol 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. 10).

(Processing Example 4)

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, and then 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added, followed by adding 0.1 mL of 35% hydrogen peroxide solution. Let. After 20 minutes of reaction at room temperature, 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 13

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, and then 0.0035 g of iron sulfate, which is frequently used as a catalyst in the conventional Fenton oxidation method, was added, and 35% hydrogen peroxide 0.1 mL. After 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 5 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, a hardly decomposable organic substance, and 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. After the reaction was carried out. After 20 minutes of reaction at room temperature, 4-chlorophenol 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 30 minutes (see FIG. 5).

Comparative Example 14

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, a hardly decomposable organic substance, and then 0.0035 g of iron sulfate, which is frequently used as a catalyst in the conventional Fenton oxidation method, was added to 35% hydrogen peroxide. 0.1 mL of water was added and reacted. After 20 minutes of reaction at room temperature, 4-chlorophenol 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 about 99% after 40 minutes (see FIG. 6).

Comparative Example 15

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, a hardly decomposable organic substance, and then 0.1 g of goethite, one of the existing iron oxides, and 0.1 mL of 35% hydrogen peroxide solution were added. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol 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 65% (see Fig. 7).

Comparative Example 16

After adding acid to 100 mL of waste water containing 200 ppm of 4-chlorophenol, which is a hardly decomposable organic substance, adjust pH to 5, add 0.1 g of hematite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol decomposed about 45%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 55% of hydrogen peroxide water remained after 40 minutes (see Fig. 7).

Comparative Example 17

After adding acid to 100 mL of waste water containing 200 ppm of 4-chlorophenol, which is a hardly decomposable organic substance, adjust pH to 5, add 0.1 g of magnetite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol decomposed about 45%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 55% of hydrogen peroxide water remained after 40 minutes (see Fig. 7).

(Processing example 6)

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, a hardly decomposable organic substance, and 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. After the reaction was carried out. After 20 minutes of reaction at room temperature, 2-chlorophenol 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 30 minutes (see FIG. 8).

Comparative Example 18

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable organic substance, and then added 0.0035 g of iron sulfate, which is frequently used as a catalyst in the conventional Fenton oxidation method, and 35% hydrogen peroxide. 0.1 mL of water was added and reacted. After 20 minutes of reaction at room temperature, 2-chlorophenol was decomposed more than 90%. 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 about 90% after 30 minutes (see Fig. 9).

Comparative Example 19

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol which is a hardly decomposable organic substance, adjust pH to 5, add 0.1 g of goethite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol 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 80% of hydrogen peroxide water remained after 40 minutes (see Fig. 10).

Comparative Example 20

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable organic substance, adjust pH to 5, add 0.1 g of hematite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol 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. 10).

Comparative Example 21

PH was adjusted to 5 by adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, a hardly decomposable organic substance, and then 0.1 g of magnetite, one of the existing iron oxides, and 0.1 mL of 35% hydrogen peroxide solution were added. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol decomposed about 25%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 70% of hydrogen peroxide water remained after 40 minutes (see Fig. 10).

(Process Example 7)

PH was adjusted to 7 by adding acid to 100 mL of wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, and then 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added and 0.1 mL of 35% hydrogen peroxide solution was added. Let. After 30 minutes of reaction at room temperature, phenol was decomposed more than 90%. 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 90% or more after 40 minutes (see Fig. 2).

Comparative Example 22

After adding acid to 100 mL of wastewater containing 200 ppm of phenol, which is a hardly decomposable organic substance, adjust pH to 7. Then, add 0.0035 g of iron sulfate which is used as a catalyst in the conventional Fenton oxidation method, and 0.1 mL of 35% hydrogen peroxide solution. After 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 Example 8)

PH was adjusted to 7 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, a hardly decomposable organic substance, and 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added, and 0.1 mL of 35% hydrogen peroxide solution was added. After the reaction was carried out. After 40 minutes of reaction at room temperature, 4-chlorophenol was decomposed more than 98%. 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 90% or more after 40 minutes (see Fig. 5).

Comparative Example 23

PH was adjusted to 7 by adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, which is a hardly decomposable organic substance. Then, 0.0035 g of iron sulfate, which is frequently used as a catalyst in the conventional Fenton oxidation method, was added, followed by 35% hydrogen peroxide. 0.1 mL of water was added and reacted. After 40 minutes of reaction at room temperature, 4-chlorophenol was hardly decomposed. 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 hardly decomposed after 40 minutes (see FIG. 6).

Comparative Example 24

After adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol, which is a hardly decomposable organic substance, pH was adjusted to 7. Then, 0.1 g of goethite, one of the existing iron oxides, was added, and 0.1 mL of 35% hydrogen peroxide solution was added. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol was decomposed about 30%. In addition, as a result of confirming the residual amount of hydrogen peroxide after the reaction, it was confirmed that more than 70% of hydrogen peroxide water remained after 40 minutes (see Fig. 7).

Comparative Example 25

After adding acid to 100 mL of wastewater containing 200 ppm of 4-chlorophenol which is a hardly decomposable organic substance, pH was adjusted to 7, and then 0.1 g of hematite, one of the existing iron oxides, and 0.1 mL of 35% hydrogen peroxide solution were added. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol was decomposed about 40%. 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. 7).

Comparative Example 26

After adding acid to 100 mL of waste water containing 200 ppm of 4-chlorophenol, which is a hardly decomposable organic substance, adjust pH to 7. Then, add 0.1 g of magnetite, one of the existing iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. The reaction was carried out. After 30 minutes of reaction at room temperature, 4-chlorophenol was decomposed about 40%. 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. 7).

(Process Example 9)

PH was adjusted to 7 by adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, a hardly decomposable organic substance, and then 0.1 g of the catalyst (iron oxide) obtained in Example 1 was added and 0.1 mL of 35% hydrogen peroxide solution After the reaction was carried out. After reacting for 40 minutes at room temperature, 2-chlorophenol 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 after 40 minutes, the hydrogen peroxide water was decomposed by 95% or more.

Comparative Example 27

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol which is a hardly decomposable organic substance, pH was adjusted to 7. 0.1 mL of water was added and reacted. After reacting for 40 minutes at room temperature, 2-chlorophenol 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 was hardly decomposed after 40 minutes (see FIG. 9).

Comparative Example 28

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable organic substance, adjust pH to 7. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol 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. 10).

Comparative Example 29

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable organic substance, pH was adjusted to 7. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol decomposed about 65%. 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 30% (see Fig. 10).

Comparative Example 30

After adding acid to 100 mL of wastewater containing 200 ppm of 2-chlorophenol, which is a hardly decomposable organic substance, adjust pH to 7. Then, add 0.1 g of magnetite, one of the iron oxides, and add 0.1 mL of 35% hydrogen peroxide solution. The reaction was carried out. After 30 minutes of reaction at room temperature, 2-chlorophenol 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. 10).

As described above, since the iron oxide catalyst of the present invention exhibits excellent decomposition rate of hardly decomposable organic matter as compared to the conventional iron oxide, it was found that different oxidation states represented by the iron oxide catalyst of the present invention are advantageous for the Fenton treatment method.

Wastewater treatment method using the iron oxide 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 the acid conditions and the treatment is 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

It can be applied to wastewater treatment in the wastewater treatment plant applying Fenton treatment method. Existing Fenton treatment method is difficult to apply to drinking water because of remaining hydrogen peroxide problem, but this treatment method does not have residual hydrogen peroxide solution and iron component is dissolved in water. It can also 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 oxide and conventional iron oxides obtained according to the production method of the present invention.

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

3 is a result of fenton oxidation of phenol using iron sulfate, which is widely used in the conventional Fenton treatment method.

Figure 4 shows the results of phenton oxidation of phenol using conventional iron oxide, namely (a) magnetite, (b) hematite, and (c) goethite.

5 is a penton oxidation result of 4-chlorophenol using iron oxide prepared according to the present invention.

6 is a result of fenton oxidation of 4-chlorophenol using iron sulfate which is widely used in the conventional fenton treatment.

7 shows the results of phenton oxidation of 4-chlorophenol using iron oxide, namely (a) magnetite, (b) hematite, and (c) goethite.

8 is a result of fenton oxidation of 2-chlorophenol using iron oxide prepared according to the present invention.

9 is a result of fenton oxidation of 2-chlorophenol using iron sulfate which is widely used in the conventional fenton treatment method.

10 shows the results of phenton oxidation of 2-chlorophenol using iron oxide, namely (a) magnetite, (b) hematite, and (c) goethite.

Claims (7)

The iron hydroxide is prepared by reacting an ionic iron with an alkali agent, and then calcined at a temperature between 100 and 1000 ° C. for 2 to 8 hours. 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 A process for producing an iron oxide catalyst for fenton oxidation, which is water or a mixture of two or more kinds. The method of claim 1, wherein the alkaline agent is selected from the group consisting of caustic soda, potassium hydroxide, ammonia, or a buffer solution made of ammonia and ammonium chloride, ammonia and ammonium sulfate. An iron oxide catalyst for fenton oxidation treatment produced according to any one of claims 1 to 3. The method of using the iron oxide 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. A method of using the iron oxide catalyst for fenton oxidation treatment according to claim 4 for drinking water treatment.