KR20050023272A - Manganese compound, process for producing the same, and method of utilization of the same - Google Patents

Abstract

Providing a manganese compound that exhibits a higher ability to remove environmental pollutants than conventional manganese oxide. A manganese compound is obtained by mixing and reacting a bivalent manganese aqueous solution and an aqueous alkali permanganate solution containing more than stoichiometric alkali. Compared with a known manganese oxide, this manganese compound is recognized that the specific surface area is greatly increased, and the improvement of the ability to remove environmental pollutants is remarkable. The manganese compounds according to the present invention have a large specific surface area, a high ability to remove environmental pollutants, odorous components emitted from each plant, NO _X , SO _X , VOC, hydrocarbons and aldehydes generated by incomplete combustion, and the like. It is useful for adsorption and oxidation removal of unburned components.

Description

Manganese compound, its manufacturing method, and its manufacturing method {MANGANESE COMPOUND, PROCESS FOR PRODUCING THE SAME, AND METHOD OF UTILIZATION OF THE SAME}

The present invention relates to a manganese compound used for removal by adsorption or oxidation of environmental pollutants, a method for producing the same, and a method for using the same. Specifically, NO _X or SO _X, VOC, also, the absorption and the manganese compound and a method of manufacturing the same for use in removing oxides such as hydrocarbons, aldehydes occurring as unburned components due to incomplete combustion of the combustion exhaust gas and use thereof It is about.

Background Art Conventionally, adsorbents such as activated carbon and zeolite have been used to remove environmental pollutants, for example, to remove odors generated from cigarette smells and garbage in buildings and automobile interiors. In general, the removal of malodor by these adsorbents was mainly caused by physical adsorption of the malodorous substance into the adsorbent.

For a remover based on manganese compounds, Japanese Patent Application Laid-Open No. 3-186317 discloses manganese oxide (surface area 240m ² / g) produced by mixing an aqueous solution of potassium permanganate and an aqueous solution of manganese sulfate containing sulfuric acid and reacting under strong acidic conditions. ) Traps and removes sulfur compounds.

Further, Japanese Patent Application Laid-Open No. 8-173765 discloses manganese oxide (surface area) by thermally decomposing manganese oxide, followed by mixing and reacting manganese oxide (surface area 84-185 m ² / g) and aqueous potassium permanganate solution with aqueous manganese acetate solution. It is disclosed that 204 m ² / g) is used as an adsorbent to remove odors of sulfur compounds.

However, when the adsorbent is used for the removal of environmental pollutants, there is a disadvantage that the adsorption capacity is limited, so that further steps such as adsorbent exchange are required. In addition, there is a drawback that the substance physically adsorbed is released due to a change in conditions such as temperature and pressure.

On the other hand, it is known to use a manganese compound, especially manganese oxide, as a method separate from adsorption, that is, as an oxidation catalyst. This catalyst has the performance of acting even at a temperature near room temperature, and it is generally known that a high surface area is preferable.

However, when the above-mentioned conventional manganese compounds are used for the removal of environmental pollutants, the removal effect thereof is not yet sufficient, and therefore, there is a demand for the development of a removal agent exhibiting higher performance.

Accordingly, it is an object of the present invention to provide a manganese compound having a significantly higher ability to remove environmental pollutants than before.

MEANS TO SOLVE THE PROBLEM In order to achieve the said objective, the present inventors earnestly examined about the method of manufacturing the manganese compound of the high surface area which has not existed conventionally, considering that it is necessary to make a manganese oxide a high surface area state.

As a result, it was found that the manganese compound having an alkaline substance in an amount of 1-10% in the material structure and having a BET surface area of 300 m ² / g or more has high adsorption capacity and oxidation catalyst performance.

And the manganese compound of this invention mixes an alkali compound and a permanganate salt with the aqueous solution of the divalent manganese salt under stirring, and makes it react, produces | generates a precipitate, wash | cleans this deposit sufficiently, and it filters and continues to dry. In the manufacturing method which consists of these, it discovered that the quantity of the alkali compound to mix can manufacture by the manufacturing method of the manganese compound characterized by more than stoichiometry with respect to permanganate.

In addition, when the removal test was conducted by the method of removing the said substance in gas by flowing and contacting the gas containing environmental pollutants to the obtained manganese compound, it discovered that the manganese compound of this invention has high removal performance, The present invention has been completed.

The present invention relates to a novel manganese compound, wherein the BET surface area is at least 300 m ² / g, preferably at least 350 m ² / g. Moreover, content of the alkaline substance in the manganese compound of this invention is 1-10% of range with respect to the compound total weight, More preferably, it is 3-9% of range.

And this invention relates to the manufacturing method of a manganese compound, Specifically, For example, Alkali permanganate aqueous solution (B liquid) which added the stoichiometric or more alkali compound to the aqueous solution (A liquid) of divalent manganese salt and permanganic acid. To prepare a precipitate by mixing and reacting the liquid B with the liquid A under stirring, and sufficiently washing the precipitate, followed by filtration, followed by drying in the range of 100 ° C to 200 ° C. .

Here, it is preferable to use acetate, sulfate, chloride, etc. as a divalent manganese salt, and it is preferable to use sodium salt, potassium salt, etc. as a permanganate salt. Moreover, it is preferable to use hydroxides or carbonates, such as sodium, potassium, and lithium, as an alkali compound for making alkali or more stoichiometric alkali exist with respect to permanganic acid.

Here, the addition amount of the alkali compound to the permanganate is preferably expressed in a molar ratio with respect to 1 mole of alkali permanganate, which is higher than 1.0 and less than 4.0. When this ratio is 1.0 or less, the quantity of an alkali compound becomes small, and finally, a manganese compound of high surface area cannot be obtained, and even if it is larger than 4, a compound of high surface area cannot be obtained. In addition, the permanganate and the alkali compound for mixing with the liquid A do not need to be prepared in advance in the form of an aqueous solution, for example, by adding a necessary amount of the mixed powder of the permanganate and the alkaline compound under stirring of the liquid A Also good.

Furthermore, as for drying temperature, 100-200 degreeC is preferable, More preferably, 120-170 degreeC is preferable. If the drying temperature is lower than 100 ° C, it is not practical because drying takes a long time, and if it is higher than 200 ° C, the surface area of the manganese compound is lowered, which is not preferable.

The manganese compound thus obtained had a BET surface area of 300 m ² / g or more. In addition, when the manganese compound of the present invention was chemically analyzed, it was found that a large amount of alkali was contained. Since the manganese compound of the present invention can be obtained by washing the reactant sufficiently with water and filtering and drying, it can be seen that alkali is not incorporated as an impurity but is contained in the substance structure. Therefore, the manganese compound of the present invention is considered to be a compound having a kind of alkali, manganese, and oxygen as a constituent rather than manganese oxide.

The present invention also relates to a method for removing environmental pollutants in a gas by circulating and contacting a gas containing an environmental pollutant in a manganese compound of the present invention. Examples of environmental pollutants include ammonia, hydrogen sulfide, mercaptanic acid, aldehydes, carbon monoxide, and the like.

Removal of environmental pollutants is generally carried out by a flow-type reactor, but other methods may be used. The removal of environmental pollutants is carried out by a method in which a manganese compound of the present invention is filled in a reaction tube, installed in an apparatus, and then a gas containing environmental pollutants is introduced into the reaction tube to remove contact therewith. The environmental pollutant removal performance is estimated by measuring the environmental pollutant concentration at the outlet side of the reaction tube and calculating the rate of decrease for the concentration at the inlet side. The removal rate of environmental pollutants of the manganese compounds of the present invention was measured, and compared with the removal rate of environmental pollutants of manganese oxide obtained according to a known method, it was confirmed that the removal rate was significantly higher than that of a known oxide. .

Hereinafter, an embodiment showing a specific configuration and effects of the present invention will be described, but the present invention is not limited thereto.

Example 1

700 g of manganese sulfate tetrahydrate was added to a precipitation tank containing 10 L of ion-exchanged water, followed by stirring to obtain a manganese sulfate solution. Furthermore, 400 g of potassium permanganate and 460 g of caustic potassium were added to a precipitation tank containing 23 L of ion-exchanged water, followed by stirring to obtain a potassium permanganate solution. Then, the potassium permanganate solution was added to the manganese sulfate solution kept at 30 ° C. with stirring, followed by reaction for 2 hours to produce a precipitate. This precipitate was filtered, washed with ion exchanged water, and dried at 120 ° C. for 14 hours to obtain a manganese compound. The specific surface area of the obtained manganese compound was 420 m ² / g, and the content of potassium was 7.8%.

Example 2

In Example 1, a manganese compound was obtained in the same manner as in Example 1 except that the addition amount of caustic potassium was 230 g. The specific surface area of the obtained manganese compound was 350 m ² / g, and the content of potassium was 3.1%.

Example 3

In Example 1, a manganese compound was obtained in the same manner as in Example 1 except that 900 g of manganese acetate was used instead of 700 g of manganese sulfate tetrahydrate. The specific surface area of the obtained manganese compound was 340 m ² / g, and the content of potassium was 3.5%.

Example 4

In Example 1, a manganese compound was obtained in the same manner as in Example 1 except that 230 g of caustic soda was used instead of 460 g of caustic potassium. The specific surface area of the obtained manganese compound was 320 m ² / g, and the content of sodium was 2.2%.

Comparative Example 1

The reagent manganese carbonate was calcined at 350 ° C. for 5 hours in air. 200 g of the obtained fired product was put into 1 L of 0.1 mol / L acetic acid aqueous solution, and stirred to perform acid treatment. After filtration and washing with ion-exchanged water, the manganese oxide of Comparative Example 1 was obtained. The specific surface area of the obtained manganese oxide was 150 m ² / g.

Comparative Example 2

In Example 1, the manganese oxide of Comparative Example 2 was obtained in the same manner as in Example 1 except that caustic potassium was not added to the aqueous potassium permanganate solution. The specific surface area of the obtained manganese compound was 230 m ² / g.

[Test Example 1] << Evaluation of Removal Performance of Environmental Pollutants >>

The performance evaluation of the manganese compound of this invention was performed by measuring the removal performance of the environmental pollutant in air. That is, the gas of the following gas compositions was measured on the following measurement conditions. The environmental pollutant removal rate was calculated | required by the following formula. In addition, the manganese compound used for evaluation evaluated what was granulated in the granule of 1-2 mm.

<< test condition >>

Gas composition

Ammonia: 20 ppm

Hydrogen sulfide: 20ppm

Mercaptan: 20 ppm

Acetaldehyde: 20 ppm

Formaldehyde: 20ppm

Carbon Monoxide: 20ppm

Air: balance

Test temperature: 25 ℃

Gas Space Velocity (SV): 100,000h ^-1

<< Calculation of environmental pollutant removal rate >>

Removal Rate = {(A-B) / A} × 100 (%)

In addition, said A and B are as follows.

A: Environmental pollutant concentration at the inlet of the reaction tube

B: environmental pollutant concentration at the exit of the reaction tube

[Table 1] Result of environmental pollutant removal rate

Environmental pollutant removal rate (%) ammonia Hydrogen sulfide Methyl mercaptan Acetoaldehyde Formaldehyde carbon monoxide Example 1 90 75 60 65 85 35 Example 2 89 70 57 63 81 32 Example 3 84 70 55 62 75 28 Example 4 85 68 53 60 73 24 Comparative Example 1 50 30 20 35 52 9 Comparative Example 2 58 36 28 41 55 4

As shown in Table 1, the manganese compound according to the present invention is remarkably excellent in removing environmental pollutants compared with known manganese oxide.

Claims (5)

A manganese compound having an BET surface area of at least 300 m ² / g, comprising an alkaline substance in an amount of 1-10% in the material structure. In the manufacturing method of the manganese compound which consists of mixing an alkali compound and a permanganate salt in the aqueous solution of the divalent manganese salt under stirring, and making it react, generating a precipitate, after wash | cleaning this deposit sufficiently, filtering and continuing to dry. The amount of the alkali compound is greater than the stoichiometry for the permanganate salt. The method for producing a manganese compound according to claim 2, wherein the amount of the alkali compound added to the permanganate is in the range of higher than 1.0 and lower than 4.0 when expressed in molar ratio with respect to 1 mol of alkali permanganate. The process for producing a manganese compound according to claim 2, wherein the drying temperature is 100-200 ° C. A method for removing environmental pollutants in gas by circulating a gas containing environmental pollutants in the manganese compound according to claim 1.