JPH05293162A - Air cleaner and its production - Google Patents

Abstract

PURPOSE:To provide the air cleaner which cleans polluted air contg. malodorous gases represented by methyl mercaptan. CONSTITUTION:This air cleaner is formed by using granular sepiolite as a carrier and carrying particulate iron oxide, particulate iron sulfate and fine sulfur on the granular sepiolite. This process for production of the air cleaner consists in impregnating an aq. iron salt soln. into the sepiolite, then calcining the sepiolite in a oxidation atmosphere and making hydrogen sulfide absorbed thereon. As a result, the air cleaner which can be used as a deodorant for household use and a deodorant for vehicles is inexpensively produced and the performance to remove CH3SH functions over a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purification product for purifying polluted air containing malodorous gases represented by methyl mercaptan and a method for producing the same. The air-purified product of the present invention can be used as, for example, a household deodorant or a vehicle deodorant.

[0002]

2. Description of the Related Art Conventionally, as a method for treating a malodorous gas in the air, an adsorption method using activated carbon, a masking method using another fragrance, a chemical method for chemically reacting an odor, or a discomfort is reduced. It is being appreciated. However, the adsorption method using activated carbon has a problem that the deodorizing performance deteriorates in a short period of time, and it has a drawback that it easily causes a fire because it easily burns. Masking methods using other fragrances are not a fundamental solution because the fragrance may add new discomfort. As a chemical method for changing the malodorous gas by a chemical reaction, for example, there is a method of oxidizing and decomposing the malodorous gas with ozone, but since excess ozone is harmful to the human body, there is a high risk of causing new harm. That is, since it is difficult to control the amount of the chemical substance that reacts with the malodorous gas, an unnecessary chemical substance is generated, and it is difficult to be a fundamental solution.

The method using activated carbon is the most popular because it is inexpensive and has high initial performance. However, it is also a fact that it has a drawback that it absorbs moisture due to its high adsorption performance, and it has a short life of being able to absorb a bad odor and it is easily burnable. Development of deodorants utilizing mineral-based porous materials such as activated alumina and sepiolite has been actively conducted. However, it is the current situation that deodorizing agents that utilize these mineral-based porous materials have not surpassed activated carbon.

[0004]

The present inventor utilizes sepiolite, which is a kind of mineral-based porous material, to provide an air-purified product which is nonflammable and has excellent demethylmercaptan performance, and a method for producing the same. Is an issue.

[0005]

The present invention is an air-purified product characterized by using granular sepiolite as a carrier, and supporting particulate iron oxide, particulate iron sulfide and fine sulfur on the granular sepiolite. ..

The present invention is also a method for producing an air-purified product, which comprises impregnating granular sepiolite with an aqueous solution of an iron salt, firing it in an oxidizing atmosphere, and then adsorbing hydrogen sulfide.

That is, according to the present invention, iron oxide particles are deposited on the surface of sepiolite by impregnating granular sepiolite with an aqueous solution of iron salt, then drying and firing in an oxidizing atmosphere. When hydrogen sulfide is adsorbed on the calcined product, iron sulfide and fine sulfur are generated on the surface of iron oxide, and a catalytic deodorizing material having excellent methyl mercaptan removal performance, that is, granular sepiolite as a carrier, and the granular sepiolite has fine particles. An air-purified product carrying iron oxide, fine iron sulfide and fine sulfur is obtained.

[0008] Sepiolite, which is used as a mineral-based porous material for various adsorbent materials, is used for various purposes as an adsorbent material as well as activated carbon. It has little effect on sulfur malodor such as methyl mercaptan and hydrogen sulfide.

In order to maintain the activity of the above-mentioned iron oxide fine particles and sulfur, a chemically stable carrier is required, and as a material for keeping a large specific surface area, for example, pores of about 200 angstrom are held. Sepiolite has ideal properties. We have researched a method for producing a catalyst in which fine particles composed mainly of iron oxide are dispersed in this sepiolite, and have completed the deodorizing material (air purification product).

[0010]

[Function] Under normal conditions, iron oxide and sepiolite have no ability to remove methyl mercaptan. Soaking in an aqueous solution of iron salt in synthetic zeolite, silica gel, activated alumina, etc., then drying and firing. Even if the same treatment as in the present invention is applied, the adsorption of hydrogen sulfide is extremely weak, and it is modified to a substance that has an adsorption ability of methyl mercaptan. I can't. Only sepiolite is adsorbed with hydrogen sulfide by immersion treatment in an iron salt aqueous solution and further subjected to heat oxidation treatment, and after adsorbing hydrogen sulfide, it has a capability of removing malodorous components such as methyl mercaptan.

Although the mechanism by which this difference occurs cannot be fully clarified, it is presumed from the fact that sepiolite is a chemically extremely stable mineral, and iron oxide fine particles are independently stable as compared with other porous minerals. It is presumed that the activity can be maintained because it is easily generated and the independence is maintained.

The granular sepiolite used in the present invention may be obtained by crushing sepiolite lumps into particles having an average particle size of 1 to 5 mm, or by forming a sepiolite particle into a sheet by adding a binder and a sizing agent. Further, a honeycomb-shaped product or the like can be applied.

As the iron salt used in the present invention, any water-soluble salt can be used. For example, ferrous sulfate, ferric sulfate, ferrous nitrate and ferric nitrate are given as examples. There are iron, ferrous chloride, ferric chloride, ferrous bromide, ammonium (II) sulfate, iron (II) acetate, etc. These are usually 0.01 to 2.0 mol per liter of sepiolite. , Preferably 0.1 to 0.5 mol.

The oxidizing atmosphere may be air, oxygen-enriched air, etc., but air is usually sufficient. The firing temperature is 1
00-400 ° C, preferably 200-350 ° C,
The firing time is 30 minutes to 5 hours, preferably 1 to 2 hours.

The adsorption amount of hydrogen sulfide is 0.01 to 0.5 mg / g, preferably 0.0 per unit weight of sepiolite.
5 to 0.2 mg / g.

The air-purified product thus obtained is
1 to 30 finely divided iron oxides per liter of sepiolite
g, preferably 5 to 10 g, and particulate iron sulfide 0.01 to
0.5 g, preferably 0.05-0.2 g and fine sulfur 0.001-0.05 g, preferably 0.005-
0.02 g is carried.

[0017]

EXAMPLES Next, examples of the present invention will be described.

Example 1 Sepiolite particles having a particle diameter of 1 to 5 mm are shown in Table 1 as ferrous sulfate 0.1 to 0.3 mol / liter, L-ascorbic acid 0 to 0.1 mol / liter, and water. Calcium oxide 0
~ 0.4 mol / l each of 5 kinds of aqueous solutions (aqueous solutions A to E) mixed for 1 minute, drained, dried in the atmosphere, and further dried in a baking furnace in an atmosphere of 200 to 4
The mixture was kept at 00 ° C. for 2 hours for heat treatment, and then cooled.
Here, the addition of L-ascorbic acid is for preventing the oxidative precipitation of iron ions, and the addition of calcium hydroxide is for raising the pH to promote the production of iron hydroxide, and the same effect is obtained. Tannic acid, potassium hydroxide, etc., which have a can be substituted for each.

10 ppm hydrogen sulfide was brought into contact with the calcined sepiolite using air as a carrier gas to adsorb hydrogen sulfide until the adsorption amount of hydrogen sulfide per unit weight of sepiolite was 0.02 to 0.20 mg / g, Each processed sepiolite was obtained.

[0020]

[Table 1]

The processed sepiolite thus obtained was allowed to stand in a room for 1 month and 3 months, and then the demethylmercaptan (hereinafter, also simply referred to as CH ₃ SH) performance was evaluated. The deodorization test device had the structure shown in FIG. 1, the internal volume was 40 liters, and the air volume of the circulation fan was about 400 liters / minute. That is, the air purification product 3 is set in the holder 7 in the closed container 1 provided with the gas inlet 4 and the gas outlet 5, and the circulation fan 2 is provided in the downstream area thereof.
Gas was circulated in the direction of the arrow. The evaluation amount of deodorant (air purification product) was 40 g each, and the sides were made of cardboard and the top and bottom were made of non-woven fabric.
The one packed in the box was installed on the entrance side of the fan to evaluate the deodorizing performance. The initial concentration was 50 ppm.

For comparison, commercially available activated carbons having a particle size of about 5 mm (two types were prepared, commercially available activated carbons A and B in Table 2 below) were also used indoors for 1 month and 3 months. After standing, a similar test was performed using 40 g each once as with processed sepiolite. The results are shown in Table 2. Table 3 shows the evaluation results of sepiolite treated with a chemical solution, a calcination treatment, and a hydrogen sulfide adsorption treatment.
As shown in (1), it was extremely good and showed a performance comparable to that of the commercially available activated carbon as a comparative material.

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

INDUSTRIAL APPLICABILITY According to the present invention, an air-purified product which is nonflammable and has high de-CH ₃ SH performance can be manufactured inexpensively and easily, and the de-CH ₃ SH performance of the obtained air-purified product is functional for a long time. , Its practical value is high.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the structure of a test device for evaluating the deodorizing performance of a deodorizing material (air purification product) used in an example of the present invention.

[Explanation of symbols]

 1 ... Airtight container 2 ... Circulation fan 3 ... Air purifier 4 ... Gas inlet 5 ... Gas exhaust 6 ... Gas circulation direction 7 ... Holder

Claims (2)

[Claims] 1. An air-purified product characterized by using granular sepiolite as a carrier, and supporting the particulate sepiolite with particulate iron oxide, particulate iron sulfide and fine sulfur. 2. A method for producing an air-purified product, which comprises impregnating granular sepiolite with an aqueous solution of an iron salt, followed by firing in an oxidizing atmosphere, and then adsorbing hydrogen sulfide.