KR20070028102A - Preparation method of nano size copper-manganese complex oxide catalyst and the catalyst prepared by the method - Google Patents

Abstract

A method for manufacturing nano size copper-manganese complex oxide catalyst and the catalyst manufactured by the same are provided to easily remove the VOC(Volatile Oxygen Compound)s harmful for the human body and to have the inexpensive manufacturing cost. Manganese nitrates hydrate and copper nitrates hydrate are melted in the distilled water. Urea is inserted into the solution. Then the carrier is inserted into the solution and then agitated. The agitated matter is dried, crushed and sintered. In the agitating process, ammonia water is added and the agitating process is performed under the condition of pH 7 to pH 9. The carrier is alumina. The catalyst has the content ratio of copper/manganese within a mole ratio of 0.43 to 1.72 mol.

Description

Preparation method of nano-size copper-manganese complex oxide catalyst and the catalyst prepared by the method

1 is a graph showing the removal efficiency of toluene at a concentration of 30 ppm using a copper-manganese oxide catalyst of nanoparticles prepared by one embodiment according to the present invention;

2 is a graph showing the removal efficiency of toluene at a concentration of 75 ppm using a copper-manganese oxide catalyst of nanoparticles prepared by one embodiment according to the present invention;

3 is a graph showing the removal efficiency of toluene at a concentration of 150 ppm using a copper-manganese oxide catalyst of nanoparticles prepared by one embodiment according to the present invention;

Figure 4 is a graph showing the removal efficiency of toluene over time at 220 ℃ and 260 ℃ using a copper-manganese oxide catalyst of nanoparticles prepared by one embodiment according to the present invention,

5A is a SEM photograph of the surface of a copper-manganese oxide catalyst of nanoparticles prepared by one embodiment of the present invention;

Figure 5b is a SEM photograph of the surface of the copper-manganese oxide catalyst of the nanoparticles prepared by another embodiment of the present invention,

Figure 5c is a SEM photograph of the surface of the copper-manganese oxide catalyst of the nanoparticles prepared by another embodiment of the present invention,

Figure 5d is a SEM photograph of the surface of the copper-manganese oxide catalyst of the nanoparticles prepared by another embodiment of the present invention,

Figure 6a is a graph analyzing the XRD before the reaction of the copper-manganese oxide catalyst of the nanoparticles prepared by one embodiment of the present invention, and

Figure 6b is a graph analyzing the XRD after the reaction of the copper-manganese oxide catalyst of the nanoparticles prepared by one embodiment of the present invention.

 The present invention relates to a method for preparing a copper-manganese oxide catalyst of nanoparticles and a catalyst prepared accordingly. More specifically, as an efficient catalyst for oxidizing harmful hydrocarbons to the human body, the production process is simple and the catalytic oxidation reaction is excellent, and in particular, a method for producing a copper-manganese oxide catalyst of nanoparticles, which is made of nanoparticles and is easy to use industrially. And to a catalyst prepared accordingly.

Recently, with increasing interest in the environment, research is focused on suppressing the occurrence of harmful environment and removing the causative agents causing the harmful environment.

Volatile Organic Compounds (VOCs) are the main sources of harmful environments.

Examples of the volatile organic compounds include acetaldehyde, ethylene, acetylene, formaldehyde, acetylene dichloride, n-hexane, acrylonitrile, isopropyl alcohol (IPA), acrylonitrile, methanol, benzene, methyl Ethyl ketone, 1,3-butadiene, methylene chloride, butane, mtb (MTBE), 1-butene, 2-butene, propylene, carbon tetrachloride, propyleneoxide, chloroform, 1,1,1-trichloroethane, cyclohexane, Trichloroethylene, 1,2-dichloroethane, gasoline, diethylamine, naphtha, crude oil, toluene and the like.

VOC, a volatile organic compound, is a source of harmful air and odors. It has harmful effects on the human body such as respiratory disorders and carcinogenicity. It also causes substances such as smog formation through photochemical reactions, odor generation, and urban ozone concentrations. It is causing environmental pollution. Therefore, developed countries have already established standard values according to various international agreements such as ISO, mandated the installation of control facilities, or prepared measures to reduce the amount according to long-term plans.

Recently, research on the removal of VOC due to bad smell and sick house syndrome, which occurs in industrial complexes, is being conducted.

In particular, the inhalation of vapors of aromatic hydrocarbons such as benzene, toluene and xylene causes acute or chronic poisoning depending on the concentration of the vapor and the time of contact with the vapor.

Acute poisoning usually occurs by inhaling high concentrations of steam in a short time. For example, 2% (20000 ppm) of benzene, toluene, and xylene in the air can cause poisoning at a rate of 5 to 10 minutes, and there is a risk of death at 30 to 60 minutes even at 7500 ppm. Therefore, in case of more than 20000ppm, it should be considered that there is a risk of acute poisoning. At first, after a short period of excitement, you may fall into deep anesthesia and die if you do not move from the polluted environment to a fresh place. After recovery, you will have a hangover for a day or two.

Chronic poisoning can occur if you continue to inhale lower concentrations of benzene, toluene and xylene. Sometimes fatigue, anemia, white blood cells are reduced. In addition, the appetite is lost, and the stomach can be injured, such as gastrointestinal abnormalities. Some people have nervous breakdowns and forgetfulness. Absorption of these substances into the human body is absorbed not only by the inhalation of steam but also by the skin by degreasing even in a liquid state, so that direct contact with bare hands or the like must be avoided.

Therefore, in order to remove the harmful effects of volatile organic compounds such as benzene, toluene, and xylene, studies on how to effectively decompose them are required. In particular, there is a demand for effective removal of such volatile organic compounds at room temperature.

 The present invention has been made to meet the above requirements, the object of the present invention is easy to remove volatile organic compounds harmful to the human body, but the manufacturing cost is low and nanoparticles made of nanoparticles can be used in various fields in the industry It is to provide a method for preparing a copper-manganese oxide catalyst.

It is a second object of the present invention to provide a copper-manganese oxide catalyst of nanoparticles which is easy to remove volatile organic compounds harmful to the human body and is low in manufacturing cost and made of nanoparticles and can be used in various fields of industry.

Copper-manganese oxide catalyst of the nanoparticles according to the present invention for achieving the above object comprises the steps of dissolving manganese nitrate hydrate and copper nitrate hydrate in distilled water;

Dissolving urea in the solution;

Adding a carrier to the solution and stirring the solution; And

And drying, pulverizing and calcining the agitated material.

The stirring step is a method for producing a copper-manganese oxide catalyst of nanoparticles, characterized in that the stirring under the conditions of pH 7 to pH 9.

The carrier is preferably alumina.

The catalyst preferably has a copper / manganese content ratio in the range of 0.43 to 1.72 in molar ratio.

Copper-manganese oxide catalyst of nanoparticles according to the present invention for achieving the second object of the present invention is prepared according to the above-described method.

Preferably, the catalyst is fine particles in powder form.

Hereinafter, with reference to the accompanying drawings and the embodiment according to the present invention will be described the present invention in more detail.

 The present invention relates to a copper-manganese oxide catalyst of nanoparticles for the oxidation of volatile organic compounds, in particular benzene, toluene, xylene.

A catalyst is a substance that itself does not change by adding a small amount to a chemical reaction and accelerating a thermodynamically possible chemical reaction. Such action by a catalyst is called "catalysis" or "catalysis".

The method of classifying catalysts includes categorization according to the catalyst material (metal catalyst, metal oxide catalyst, etc.) or categorization according to the function of the catalyst (oxidation reaction catalyst, polymerization catalyst, hydrogenation reaction catalyst, etc.) and catalyst considering both the material and function May be classified as a metal oxide catalyst and an oxidation catalyst or a dehydrogenation catalyst.

According to the classification according to the catalyst material, specifically noble metal catalysts such as Pt, Pb, Ir, Rh; Metal catalysts such as Fe, Ni, Co; Metal oxide catalysts such as MgO, TiO 2, V 2 O 5, ZnO; Complex oxide catalysts such as Fe 2 O 3 -MoO 3, Mo-V-P-O; Solid acid catalysts such as zeolites and heteropolyacids; Inorganic acid catalysts such as HF, H 2 SO 4, H 3 PO 4; Ion exchange resin catalysts such as Amberlyst-15.

These catalysts are all generally known to exhibit effective catalytic reactions for the required reactions. However, these catalysts have the disadvantage that they are mostly expensive.

The present invention is directed to a novel copper-manganese oxide catalyst other than the previously known catalysts.

To prepare a copper-manganese oxide catalyst of nanoparticles according to the present invention, manganese nitrate hydrate and copper nitrate hydrate are first dissolved in distilled water.

Manganese nitrate hydrate is a hydrate of manganese nitrate (Mn (NO), manganese nitrate), and includes hexahydrate, tetrahydrate, dihydrate, monohydrate, and the like. It is known to act primarily as a catalyst. Among them, Mn (NO) 6 H ₂ O, which is a hexahydrate, is decomposed well in polar solvents such as water and ethanol, and therefore, Mn (NO) 6 H ₂ O is preferably used in the present invention, but is not necessarily limited thereto.

Copper nitrate hydrate is a hydrate of copper nitrate (Cu (NO)), and trihydrate, hexahydrate, hexahydrate and the like. Both hexahydrate and trihydrate are blue crystals with deliquescent properties and are soluble in water and ethanol. There is no particular limitation on the copper nitrate hydrate that can be used in the present invention.

In addition to manganese nitrate hydrate and copper nitrate hydrate, there are no limitations on using manganese oxide and copper oxide that are easily soluble and readily available.

Then, urea is added to a solution in which manganese nitrate hydrate and copper nitrate hydrate are dissolved and dissolved together.

The carrier is then put together in the solution and stirred while maintaining a neutral atmosphere.

As the carrier usable in the present invention, a carrier which can generally support particles and provide appropriate dispersion can be used. Preferably the carrier is stable in the local environment in which the catalyst is used. The carrier preferably has a surface area sufficient to provide dispersion of the metal particles. Carriers with a large surface area bring more intimate contact between the reactants and the catalyst material.

Carriers that may be used in the present invention may include one or more inorganic oxides. Inorganic oxides preferably include metal oxides. Preferred metal oxides include, but are not limited to, oxides of nickel, manganese oxides, zirconium oxides, at least one oxide selected from oxides of La, Y, Ce, Pr or Nd, silica, alumina and the like.

Preferably, the carrier is spherical and the particles are fine. The more spherical and the finer the particles, the higher the surface area, so that the catalytic reaction can occur effectively.

As the carrier usable in the present invention, alumina is preferably used.

Ammonia water is added to maintain the pH of the solution in the range of 7-9. Since ammonia water is easily volatilized at room temperature, ammonia water is continuously added to supplement volatilized ammonia water.

In order to uniformly support the copper manganese catalyst with nanoparticles, the pH atmosphere of the solution is properly maintained to be in the range of pH 7 to pH 9 and stirred for 4 hours at a constant temperature of 60 ℃.

The stirred solution is then dried and ground to the desired fine particle size. Then, a calcination reaction is performed in the high temperature region to prepare a copper-manganese oxide catalyst of nanoparticles.

The catalyst material according to the invention is formed such that the oxide contains copper and manganese in the carrier. This is represented by the formula (1).

Cu _x Mn _y O _z

In said formula, X, Y, Z is an integer larger than 0, respectively.

In the catalyst according to the present invention, it is preferable that the content ratio of copper / manganese is in the range of 0.43 mol to 1.72 mol in molar ratio.

 If the copper content is less than 0.43 moles with respect to the manganese content, the oxidation function by the expected catalyst, i.e., the toluene removal function is insignificant, and if the copper content is greater than 1.72 moles with the molar ratio, the copper content is excessive compared to the manganese, rather the catalytic function. This is because it is not activated.

Volatile organic compounds, in particular aromatic hydrocarbons such as benzene, toluene and xylene, are subject to oxidation by the catalyst according to the invention. This oxidation breaks down hydrocarbons into carbon dioxide and water vapor, which are harmless to the human body. This is represented by the following scheme.

C _m H _2n + (m + n / 2) O ₂ → mCO ₂ + nH ₂ O + calories

In particular, the copper-manganese oxide catalyst of the nanoparticles prepared according to the present invention has a very fine particle size, and thus has a large surface area and a wider unit area contributing to the oxidation of hydrocarbons, so that more effective catalytic reaction can be expected. .

In addition, it is prepared as a powder form of the fine particles can be various industrial applications.

Hereinafter, although an Example concerning this invention is given and this invention is demonstrated, this invention is not limited by this Example.

{Example}

Production Example

A solution in which manganese nitrate hydrate and copper nitrate hydrate was dissolved in distilled water was prepared. Urea was dissolved together in this solution and then impregnated with gamma alumina to be used as catalyst carrier. Then, ammonia water was continuously added at a temperature of 60 ° C. and stirred for 4 hours while maintaining pH8.

Then, it was dried for 24 hours at 120 ℃ and then pulverized to 150 mesh (mesh, the same value as 104 microns) or less.

The pulverized product was then calcined at 500 ° C. for 5 hours in an air atmosphere.

Thus, a copper-manganese oxide catalyst of nanoparticles was prepared.

Example  One

A copper-manganese oxide catalyst of nanoparticles was prepared according to the preparation example, and a copper-manganese oxide catalyst of nanoparticles having a content ratio of 0.43 mol in a molar ratio of copper / manganese was prepared.

Example  2

 A copper-manganese oxide catalyst of nanoparticles was prepared according to the preparation example, and a copper-manganese oxide catalyst of nanoparticles having a copper / manganese content ratio of 0.86 mol in molar ratio was prepared.

Example  3

A copper-manganese oxide catalyst of nanoparticles was prepared according to the preparation example, and a copper-manganese oxide catalyst of nanoparticles having a copper / manganese content ratio of 1.29 mol in molar ratio was prepared.

Example  4

A copper-manganese oxide catalyst of nanoparticles was prepared according to the preparation example, and a copper-manganese oxide catalyst of nanoparticles having a copper / manganese content ratio of 1.72 mol in molar ratio was prepared.

{Test}

The efficiency of the toluene oxidation reaction was tested using the copper-manganese composite oxide catalyst prepared according to Examples 1 to 4.

The oxidation reaction was reacted after sufficiently adsorbing for the first 3 hours in consideration of the adsorption characteristics of the catalyst. The reactor temperature was raised to 100 ° C. and 20 ° C. until the temperature reached 260 ° C. After stabilization for 1 hour at each temperature from 100 ℃ to 260 ℃ was analyzed.

Toluene gas, a reaction gas, was introduced into the reactor at a flow rate of 21 vol% oxygen and 50 ml / min at concentrations of 30 ppm, 75 ppm, and 150 ppm, respectively.

Reaction gas and post-reaction gas components were analyzed and calculated via gas chromatography (manufactured by Agilent, 6890II GB-FID).

The test results are shown in FIGS. 1, 2, and 3.

1 is a graph showing the results of the catalysts according to Examples 1 to 4 toluene removal efficiency according to the reaction temperature when the toluene gas is 30ppm in the test.

Referring to FIG. 1, the horizontal axis represents temperature (° C.), and the vertical axis represents conversion of toluene, that is, removal rate of toluene (%).

In the case of the catalysts according to Examples 1 and 2, the removal rate of toluene was about 10% at 100 ° C, but the toluene removal rate gradually increased and the toluene removal rate reached almost 80% as the temperature increased.

In the case of the catalyst according to Example 4, the removal rate of toluene was about 0% at 100 ° C., but the toluene removal rate gradually increased as the temperature was increased, and the toluene removal rate reached almost 80% after passing through 240 ° C.

In the case of the catalyst according to Example 3, the removal rate of toluene was about 20% at 100 ° C, and it was found that the catalyst according to Example 3 was the most excellent in removing toluene having a concentration of 30 ppm at a relatively low temperature.

 Figure 2 is a graph showing the results of the catalyst according to Examples 1 to 4 toluene removal efficiency according to the reaction temperature when the toluene gas is 75ppm in the test.

Referring to FIG. 2, the horizontal axis shows temperature (° C.), and the vertical axis shows removal rate of toluene (%).

The copper-manganese oxide catalyst of the nanoparticles according to Examples 1 to 3 exhibited a toluene removal efficiency of approximately 5% at 100 ° C., but the toluene removal efficiency gradually increased as the temperature increased. The copper-manganese oxide catalyst of the nanoparticles according to Example 4 exhibited a toluene removal efficiency of approximately 0% at 100 ° C., but the toluene removal efficiency gradually increased as the temperature increased.

Except for Example 1, the catalysts according to Examples 2, 3 and 4 exhibited nearly 92% toluene removal efficiency at approximately 260 ° C. However, in the case of the catalyst according to Example 1, the copper-manganese composite oxide catalyst according to Example 2 and Example 4 exhibited nearly 92% of toluene removal efficiency while passing about 260 ° C. at the same temperature.

On the other hand, as can be seen from the graph, a catalyst having a relatively good toluene removal rate with increasing temperature was the catalyst according to Example 3.

Figure 3 is a graph showing the results of the catalyst according to Examples 1 to 4 toluene removal efficiency according to the reaction temperature when the toluene gas is 150ppm in the test.

Referring to FIG. 3, the horizontal axis shows temperature (° C.) and the vertical axis shows the removal rate of toluene (%).

In the catalysts according to Examples 1 to 4, the removal rate of toluene was about 0% at 100 ° C., and the toluene removal rate did not increase much even at elevated temperatures.

However, after about 220 ° C., the toluene removal rate was steeply increased, and finally, after about 260 ° C., the toluene removal rate of the catalysts according to Examples 3 and 4 reached almost 99%, and Examples 1 and 2 The catalyst also showed a toluene removal efficiency of more than 80% at 260 ℃.

Therefore, the toluene removal efficiency by the catalysts according to Examples 1 to 4 is quite excellent, and it can be seen that particularly 1.29Cu / Mn oxide catalyst according to Example 3 is more preferable.

On the other hand, Figure 4 is a graph of the toluene removal efficiency over time by testing the toluene oxidation reaction for 10 days at a fixed temperature of 220 ℃ and 260 ℃ 150 toluene concentration using a 1.29Cu / Mn oxide catalyst according to Example 3 It is shown. In this test, the toluene flow rate was 100 ml / min.

Referring to FIG. 4, the vertical axis shows the toluene removal efficiency in the same manner, while the horizontal axis shows the progress of day as the time axis for the toluene removal experiment by the catalytic reaction.

As can be seen in Figure 4, even if the toluene was oxidized using a 1.29Cu / Mn oxide catalyst at 220 ℃ there was no change in the removal rate with time, the removal rate was constantly maintained about 20%. In addition, at 260 ° C, the toluene removal rate was 100% from the beginning, and the toluene removal rate was consistently 100% even after time.

In other words, it can be seen that the oxidation reaction by the copper-manganese oxide catalyst maintains the catalyst function even after time passes at a constant temperature, so that the catalytic reaction can be continued.

5A, 5B, 5C and 5D show scanning electron microscopes (SEMs) of the surface of the copper-manganese oxide catalyst of the nanoparticles according to Examples 1, 2, 3 and 4, respectively. Picture taken with.

Referring to each photo, it can be seen that the individual particles are formed in nano size and are not perfect but exist in spherical shape.

The copper-manganese oxide catalyst formed of spherical nanoparticles provides a large surface area for the oxidation of hydrocarbons, and thus can be predicted to have excellent removal efficiency of harmful hydrocarbons.

6A and 6B are XRD (X-ray) showing that the crystal structure of the catalyst before and after the catalytic reaction of the catalysts according to Examples 1, 2, 3 and 4 was measured using an X-ray diffractometer. Diffraction) shows the results of the graph. 6A shows the result before the catalytic reaction of the catalyst according to each example, and FIG. 6B shows the result after the catalytic reaction of the catalyst according to each example.

6A and 6B, the horizontal axis represents 2θ values, and the vertical axis represents counts, that is, intensity. 6A and 6B, it can be seen that there is almost no change in the crystal phase of Cu _1.5 Mn _1.5 O ₄ , which is assumed to be an active site in the toluene removal reaction.

As described above, according to the present invention, by using the copper-manganese oxide of the nanoparticles as a catalyst, it is possible to more effectively remove volatile organic compounds harmful to the human body, especially aromatic hydrocarbon compounds such as benzene, toluene and xylene. The production cost of the copper-manganese composite oxide catalyst is inexpensive and the process is simple, so that it can be commercialized in the air pollution emission process.

In addition, since the catalyst is made of nanoparticles, it is applied to electronic materials or interior materials of buildings to remove harmful substances, and thus it can be applied to the manufacture of environment-friendly products. .

In the above described and illustrated with respect to the preferred embodiment of the present invention, the present invention is not limited to the specific preferred embodiment described above, in the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

Claims (6)

Dissolving manganese nitrate hydrate and copper nitrate hydrate in distilled water; Dissolving urea in the solution; Adding a carrier to the solution and stirring the solution; And Drying, pulverizing and calcining the agitated; method for producing a copper-manganese oxide catalyst of nanoparticles comprising a. The method of claim 1, The stirring step is a method for producing a copper-manganese oxide catalyst of nanoparticles, characterized in that the addition of ammonia water and stirring under the conditions of pH 7 to pH 9. The method of claim 1, The carrier is a method for producing a copper-manganese oxide catalyst of nanoparticles, characterized in that the alumina. The method of claim 1, The catalyst is a method for producing a copper-manganese oxide catalyst of nanoparticles, characterized in that the copper / manganese content ratio in the molar ratio of 0.43 mol to 1.72 mol. Copper-manganese oxide catalyst of nanoparticles according to the method of claim 1. The method of claim 5, The catalyst Cu _{1 .5} Mn _{1 .5} O of the nanoparticles according to claim ₄ in the crystalline phase of copper-manganese oxide catalyst.

Images