JPH07812A - Production of air purifier - Google Patents

Abstract

PURPOSE:To remove CH3CHO(acetaldehyde), a main component of tobacco smoke. CONSTITUTION:The subject air purifier is produced by a method wherein a double salt of an Al metal salt and N2H4 is on the supported surface of particles of a laminar clay mineral based on silicate with a specific surface area of 50m<2>/g min. The laminar clay mineral based on silicate is treated previously using an acid so that the mineral is allowed to bleed out. The laminar clay mineral based on silicate is thermally treated at 400 deg. to 700 deg.C in advance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an air-purified product which removes CH ₃ CHO (acetaldehyde) which is a main component of tobacco odor.

The air-purified product of the present invention can be used, for example, as a household deodorant, a vehicle deodorant, or a deodorant incorporated in an air conditioner.

[0003]

2. Description of the Related Art Odorous gas in the air is removed by an adsorption method using activated carbon, a masking method using another fragrance, or a chemical method of chemically reacting an odor, or reducing discomfort. ing.

However, the adsorption method using activated carbon has a problem that the deodorizing performance is deteriorated in a short period of time, and it is flammable, which causes a fire.

Masking methods using other fragrances are not a fundamental solution because the fragrance may give new discomfort.

As a chemical method of chemically reacting, for example, there is a method of oxidizing and decomposing a malodorous gas with ozone, but excessive ozone is harmful to the human body and causes 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 achieve a fundamental solution.

In particular, CH ₃ which is the main component of cigarette odor
For removal of CHO, activated carbon is difficult to remove.
As in 6-53744, aniline having a high chemical reactivity is attached to activated carbon to improve the removal performance, and JP-A-56-56
Although various countermeasures such as chemical reaction with phenylhydrazine to remove the same have been adopted as in No. 95319, the present inventors have found that the odor of the chemically reactive substance itself becomes a problem, It is difficult to maintain the activity of the syrup and has a weakness such as a short life.

The present inventors have invented a deodorizing agent which improves the de-CH ₃ CHO rate and exerts the de-CH ₃ CHO performance for a long period of time, and has previously proposed it in Japanese Patent Application No. 04-018173. That is, a double salt of a metal salt and hydrazine is produced.

[0010] Hydrazine is a highly reactive substance having a strong reducing power, and also has a strong self-decomposability and naturally NH ₃ , N ₂ , and H.
_Although it is a substance that decomposes or oxidizes into ₂ O etc., its chemical stability is increased by using a double salt with a metal salt,
The hydrazine can be stable until it reacts with more active gases.

CH ₃ is a gas having stronger activity.
There are aldehydes such as CHO, and since they have strong chemical adsorption with hydrazine, they are taken into double salts and the air can be cleaned.

It has been found that the specific surface area must be kept large in order to effectively work the double salt of the above metal salt and hydrazine, and that layered clay minerals such as chain magnesium silicate are excellent as carriers. It was

These compositions can be manufactured at low cost, and the deterioration of the air cleaning power is extremely small, and the problems of the prior arts have been solved.

However, there was some concern about the stable availability of the carrier, for example, chain-shaped magnesium silicate.

[0015] Chain-shaped magnesium silicate itself is a natural clay mineral and is much cheaper than synthetic clay, but no industrially profitable production area has been found in Japan, and it is necessary to rely on imports. Because it is a clay mineral that you do not get,
A carrier material that can be stably obtained in Japan has been desired.

Further, in order to inexpensively produce a deodorant having a high deodorizing performance by using the double salt of the above metal salt and hydrazine, it is essential that the compound can be molded and shaped without adding a binder.

The deodorant moldings obtained by kneading and molding the mixed aqueous solution of the metal salt and hydrazine and the layered clay mineral and then performing the drying treatment satisfy the above conditions under a specific atmosphere, but dew condensation due to water vapor occurs. It was desired to solve the deflocculating property that the molded body collapses when it occurs.

[0018]

DISCLOSURE OF THE INVENTION The present invention expands the types of compositions as a carrier, secures a more stable route of obtaining raw materials, and copes with a wide range of changes in temperature and humidity. The purpose is to provide materials that can.

[0019]

The present invention has a specific surface area of 5
A method for producing an air-purified product, characterized in that a metal salt of Al and a double salt of N ₂ H ₄ are carried on the surface of particles of a layered clay mineral mainly composed of silicic acid of 0 m ² / g or more.

Further, the present invention is the method for producing an air-purified product according to claim 1, wherein the layered clay mineral mainly composed of silicic acid is previously subjected to an elution treatment with an acid.

Further, the present invention is the method for producing an air-purified product according to claim 1 or 2, wherein the layered clay mineral mainly composed of silicic acid is preheated to 400 to 700 ° C.

[0022]

When various clay minerals were evaluated as a carrier of the above various metal salt hydrazine double salts, the chemical stability of the metal salt of Al was inhibited by selectively using the metal hydrazine double salt of Al. The characteristics common to the function as a carrier that exerts the performance as an air purifying substance without any special feature are that the specific surface area measured by N ₂ adsorption method is as large as 50 m ² / g or more, and the surface layer seen as a microstructure is made of silicic acid. It has been found that the layered clay minerals used can be used, and the present invention has been completed.

The specific surface area of the particles of the layered clay mineral mainly composed of silicic acid varies depending on the kind of the composition, and the deodorizing performance is respectively improved by supporting the metal salt hydrazine double salt of Al on the particle surface of the layered clay mineral. Is expressed,
In order to express the deodorizing performance at a practical level, it is essential that the specific surface area is 50 m ² / g or more, and the larger the specific surface area, the higher the deodorizing performance can be obtained.

The layered clay mineral mainly composed of silicic acid inevitably contains metal oxides other than silicic acid, and the metal oxides other than silicic acid existing in the surface layer, specifically iron, aluminum and magnesium, are It has a function of impairing the stability of the metal salt of hydrazine double salt of Al.

In particular, the influence of iron oxides on hydrazine is great, and for example, when iron oxides of 5% or more appear on the surface of mineral particles, hydrazine is consumed depending on the amount.

Therefore, it is desirable to reduce the amount of iron oxide manifested on the surface of the mineral particles to less than 5%.

The effect of aluminum oxide and magnesium oxide on hydrazine is smaller than that of iron oxide, but the amount of aluminum oxide manifested on the surface of mineral particles is 25%.
Less, and the amount of magnesium oxide is desirably reduced to less than 30%.

As described above, the smaller the amount of metal oxides other than silicic acid present in the surface layer of the particles of the layered clay mineral, the more the consumption of hydrazine is suppressed, but it varies depending on the origin and type of the composition. Is.

According to the present invention, the layered clay mineral mainly composed of silicic acid is preliminarily subjected to an elution treatment with an acid, for example, sulfuric acid, so that silicic acid existing in the surface layer portion is not eluted.
Since the impure metal oxides such as iron, aluminum and magnesium are eluted and removed, the deodorizing performance of the above double salt can be improved.

In the elution treatment of the impure metal oxide with the acid of the layered clay mineral mainly composed of silicic acid, the container is charged with a predetermined amount of the layered clay mineral and an aqueous solution of 1 to 2N, and then stirred and sufficiently mixed. Then, for example, by allowing it to stand for 24 hours, iron, aluminum intervening in the surface layer of the clay particles,
Metal oxides such as magnesium can be eluted.

In addition, since the micro craters formed on the surface layer of the particles of the mineral increase the specific surface area of the particles by the elution treatment of the layered clay mineral mainly composed of silicic acid with the acid, the elution time with the acid is increased. By adjusting, the specific surface area of the layered clay mineral can be arbitrarily improved.

For example, the specific surface area of talc particles is about 30.
is a m ² / g, in which the acid treatment can be increased to more than 50 m ² / g by performing 24 hours. The deodorizing performance of an air-purified product having such a particle group as a carrier is certainly enhanced.

Further, according to the present invention, since the layered clay mineral mainly composed of silicic acid is preheated to 400 to 700 ° C., the water of crystallization can be decomposed and dissipated, and the particles, the metal salt of Al and hydrazine are mixed. It can be presumed that the hydration reaction after the kneading with the aqueous solution, the hydration reaction after the molding, and the binding due to the binder effect of the double salt itself proceed, and as a result, the disintegration does not occur even when the water is subsequently contacted.

In the heat treatment of this layered clay mineral, another important thing is to set the temperature at which the recrystallization and sintering of the mineral are not reached, and this makes it possible to reduce the specific surface area of the mineral particles. The problem can be resolved.

Since the decomposition temperature, recrystallization and sintering temperature of the water of crystallization by heating the layered clay mineral mainly composed of silicic acid differ depending on the composition of the mineral, the heating temperature is selected for each composition.

When the heating temperature is lower than 400 ° C., the water of crystallization of minerals is not sufficiently decomposed, so that the binding force due to the hydration reaction is small and the molded product collapses when contacted with water.

On the contrary, if the heating temperature exceeds 700 ° C., the water of crystallization is completely decomposed, but the recrystallization proceeds to reduce the specific surface area of the particles, and the effect of supporting the deodorant is reduced.

[0038]

Example 1 Talc, kaolinite, sepiolite, bentonite, activated bentonite, montmorillonite, activated montmorillonite, alumina, activated alumina, silica gel, synthetic zeolite, cordierite, zirconia,
Mineral fine powder such as titania is mixed with a mixed aqueous solution of aluminum sulfate and hydrazine, kneaded, molded into a plate with a thickness of 1 mm, and dried at 100 ° C for 6 hours and at room temperature for 2 weeks, and then the acetaldehyde equilibrium concentration adsorption capacity Was measured.

The concentration of the mixed aqueous solution of aluminum sulfate and hydrazine was 0.5 mol / l of aluminum ion, 0.5 mol / l of hydrazine and 0.75 mol / l of sulfate ion, and the mixing ratio of the mineral powder and the aqueous solution was plate-like. The clay was made to be easy to mold and varied depending on the type of mineral, but the ratio was 100 to 150 cc of the aqueous solution to 100 g of powder.

Crush each dried plate in a mortar and
A powder having a size of 00 μ or less was used as an evaluation sample, and the equilibrium concentration adsorption capacity of CH ₃ CHO was evaluated using a Tedlar pack as shown in FIG.

The original equilibrium concentration adsorption capacity is a constant concentration of CH.
Air containing ₃ CHO is enclosed in a Tedlar pack together with the evaluation sample in a fixed volume, and the residual concentration of CH ₃ CHO after 48 hours is measured. The residual concentration, that is, the equilibrium reached concentration is in the wide range of 1 ppm to 200 ppm. It is common to repeat the test with various sample weights.

In order to make the evaluation simple, this time, the volume of the air enclosed in the Tedlar pack was 5 liters, the initial concentration of CH ₃ CHO was 2000 ppm, and the weight of the evaluation sample was 0.1 g, 0.2 g, and 0.5 g. It was limited to 3 types and evaluated by the residual concentration after 48 hours.

Table 1 shows the specific surface area and the main mineral composition of the evaluated minerals by the N ₂ adsorption method. In addition, Table ₃ shows CH ₃
The evaluation results of the adsorption capacity of CHO are shown.

From this table, it was found that minerals other than chain-like magnesium silicate also have a large specific surface area, and minerals mainly containing silicic acid show extremely high CH ₃ CHO adsorption capacity.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

Example 2 Mineral fine powders of activated bentonite, montmorillonite, activated montmorillonite, sepiolite and the like were kept at 300 ° C. to 900 ° C. for 3 hours in an air atmosphere and then cooled.

Each powder was mixed with a mixed aqueous solution of aluminum sulfate and hydrazine, kneaded, molded into a plate having a thickness of 1 mm, dried at 100 ° C. for 6 hours and at room temperature for 2 weeks, and then the acetaldehyde equilibrium concentration adsorption capacity was obtained. Was measured.

The concentration of the mixed aqueous solution of aluminum sulfate and hydrazine was 0.5 mol / l of aluminum ion, 0.5 mol / l of hydrazine and 0.75 mol / l of sulfate ion, and the mixing ratio of the mineral powder and the aqueous solution was plate-like. The clay was made to be easily spread and varied depending on the type of mineral, but the ratio was 80 to 130 cc of the aqueous solution to 100 g of the powder.

For comparison, each mineral was subjected to the same chemical treatment for those not subjected to the heat treatment to produce evaluation samples.

Crush each dried plate in a mortar and
Using a Tedlar pack, the equilibrium concentration adsorption capacity of CH ₃ CHO was evaluated, and the plate-like product was put into water to investigate the state of collapse.

The original equilibrium concentration adsorption capacity is a constant concentration of CH.
Air containing ₃ CHO is enclosed in a Tedlar pack together with the evaluation sample in a fixed volume, and the residual concentration of CH ₃ CHO after 48 hours is measured. The residual concentration, that is, the equilibrium reached concentration is in the wide range of 1 ppm to 200 ppm. It is common to repeat the test with various sample weights.

In order to make the evaluation simple, this time, the volume of air enclosed in the Tedlar pack was 5 liters, the initial concentration of CH ₃ CHO was 2000 ppm, and the weight of the evaluation sample was 0.1 g, 0.2 g, and 0.5 g. It was limited to 3 types and evaluated by the residual concentration after 48 hours.

Table 3 shows the evaluation results of the adsorption capacity of CH ₃ CHO as the evaluation mineral and the disintegration phenomenon when it was put into water.

From this table, no heat treatment, 300 ° C
In the following heat treatment, the molded body collapses on contact with water, and in the heat treatment at 400 ° C to 700 ° C, the molded body does not collapse on contact with water, and the CH ₃ CHO adsorption capacity does not cause heating. It can be seen that it is comparable to the processed product.

Further, it is clear that in the heat treatment at 800 ° C. or higher, the CH ₃ CHO adsorption capacity is deteriorated by the contact with water, although the decomposition does not occur.

[0057]

[Table 3]

[0058]

EFFECTS OF THE INVENTION According to the present invention, it is possible to inexpensively and stably produce an air-purified product having high CH ₃ CHO removal performance.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a test method for evaluating deodorizing performance.

[Explanation of symbols]

 1 Tedlar pack 2 Powder sample 3 Gas inlet and gas concentration detection port

Claims (3)

[Claims] 1. An air cleaner comprising a metal salt of Al and a double salt of N ₂ H ₄ supported on the surface of particles of a layered clay mineral mainly composed of silicic acid having a specific surface area of 50 m ² / g or more. Method for producing compound. 2. The layered clay mineral containing silicic acid as a main component,
The elution treatment with an acid is carried out in advance.
A method for producing the air-purified product described. 3. The layered clay mineral containing silicic acid as a main component,
The method for producing an air-purified product according to claim 1 or 2, wherein heat treatment is performed in advance at 400 ° C to 700 ° C.