JPH0857306A - Isothiocyanic ester deodorant and deodrizing device - Google Patents

Abstract

PURPOSE: To obtain an isothiocyanic ester deodorant having an excellent deodorizing effect especially to allyl isothiocyanate, securing the high safety and easy to handle by adding cerium oxide or cerium oxide and other metal oxide to a porous material such as activated carbon. CONSTITUTION: Cerium oxide or cerium oxide and one or more kinds of metal oxides such as oxides of V, Mn, Cu, Fe and Mo are added to a porous material such as the activated carbon to obtain the objective isothiocyanic ester deodorant. Cerium oxide is preferably added by 0.5-30 parts per 100 parts of the porous material. When an isothiocyanic ester deodorizing filter is assembled, nonwoven fabrics 4 are joined to a honeycomb substrate 2 with cobwebby adhesive sheets 5 by hot pressing or other method, the isothiocyanic ester deodorant 3 is uniformly sprinkled on the fabrics 4 and adhesive sheets 5 are put, on the deodorant 3 and hot-pressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing agent and a deodorizing device for isothiocyanate-containing gas.
More specifically, it is a deodorant and a deodorizing device which are excellent in the adsorption / removal property of isothiocyanic acid ester vapor evaporated in a gas such as air.

[0002]

2. Description of the Related Art When storing home appliances such as refrigerators in a warehouse, it is necessary to sterilize the appliances. Since the bactericide used for this purpose must be safe and harmless in terms of food hygiene, it is preferable to use, for example, an atmosphere containing a component contained in the food and having a bactericidal effect as the bactericide. From such a viewpoint, an atmosphere containing a trace amount of vapor of allyl isothiocyanate, which is known as a component of mustard oil, in the air is a preferable bactericide and used for such purpose.

However, since allyl isothiocyanate has a horseradish odor, it is necessary to deodorize this gas after using it as a germicide. For this reason, noble metal catalysts and the like that decompose and deodorize at high temperatures have been conventionally known as deodorants to be applied, but no one that can decompose and deodorize at room temperature in a short time is known. The development of such a new deodorant has been awaited.

On the other hand, generally, activated carbon is often used as a malodorous gas deodorant. Activated carbon is a unique material that has extremely excellent adsorptivity as a non-polar adsorbent, and exhibits high adsorptivity for almost all gaseous substances. However, it is difficult to sufficiently remove the odor of the isothiocyanate ester only by using ordinary activated carbon.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to deodorize a gas containing isothiocyanate ester vapor used for the purpose of sterilization or the like at room temperature in a short time. Therefore, a new composition and deodorizing device having an excellent deodorizing effect on allyl isothiocyanate, which is a particular problem, and having excellent deodorizing properties of gas containing isothiocyanate vapor, which is highly safe and easy to handle. Is to provide.

[0006]

Means for Solving the Problems The present inventor has conducted various studies in search of a new composition which is excellent in the adsorption of isothiocyanate in the gas phase and can exert a sufficient deodorizing effect particularly at room temperature. As a result, in addition to cerium oxide or cerium oxide, a composition obtained by impregnating a porous material such as activated carbon with one or more metal oxides such as vanadium, manganese, copper, iron and molybdenum is obtained. High oxidation catalytic ability,
It was found that the isothiocyanate in the gas phase has a very high deodorizing property at room temperature.

Based on this, the present invention has been achieved as a result of further studying the composition of the deodorant, the carrier for supporting it, and the deodorizing device.

That is, cerium oxide, or a porous substance impregnated with cerium oxide and other metal oxides,
It is a gas deodorant containing isothiocyanate ester mixed with activated carbon. Here, the amount of cerium oxide attached to the porous material is 100 parts by weight of the porous material (hereinafter,
It is more preferable that cerium oxide is 0.5 to 30 parts with respect to (hereinafter simply referred to as “part”), and activated carbon is preferable as the porous material. Further, the present invention includes a deodorizing device using this deodorant.

The present invention will be described in detail below.

The deodorant for isothiocyanate of the present invention must be a composition in which cerium oxide or a porous substance impregnated with cerium oxide and another metal oxide is mixed with activated carbon.

The term "porous material" as used herein often means that the surface thereof is composed of pores or microcracks, but not only the surface of these materials that can be observed from the outside, but also many pores or cracks inside. Material containing faces, ie
A substance having a remarkably large specific surface area. Further, since these substances have a large specific surface area, they exhibit high adsorptivity by Van der Waals forces.

In the present invention, of these, any material can be widely used as long as it does not deteriorate the metal oxide and has a large specific surface area and high adsorptivity as described above. For example, activated carbon, zeolite, activated alumina, silica gel,
Examples include zirconia and titania.

The activated carbon used as the carrier for the metal oxide has a large specific surface area of several 100 m ² per 1 g or more, and can be widely used as long as it is a carbon material exhibiting a high adsorptivity. As the raw material of the activated carbon, a charcoal such as coconut shell or wood or coal is usually used, but any may be used. The activation method may also be a method obtained by activation at a high temperature with steam or carbon dioxide, or a method of treatment with a chemical such as zinc chloride, phosphoric acid, concentrated sulfuric acid or the like.

The shape of the activated carbon may be any of crushed coal, granulated coal and granulated coal, but a sheet-shaped adsorption layer impregnated with the granulated carbon or activated carbon is convenient for handling such as pressure loss and replacement. Granulated coal is added to 100 parts of carbon material according to the conventional method.
It is prepared by adding ~ 60 parts of petroleum pitch or coal tar as a binder, mixing and activating the mixture, and then activating.

The zeolite used in the present invention is an aluminosilicate, which is a substance having a three-dimensional skeleton and a pore structure formed in the voids. It has a large specific surface area of more than 500 m ² / g and high adsorptivity based on it. Its composition,
The structure is not particularly limited, and both natural products and synthetic products can be used. Further, the pore volume, particle size, and shape are not particularly limited, but the pore volume depends on the adsorption capacity of metal oxide and the pressure loss.
At 0.3 ml / g or more, particle size is 50 mesh or less (particle size is about 0.3 mm
Or more) is preferable.

The activated alumina used in the present invention is mainly composed of aluminum oxide, has a porous structure, and exhibits a high adsorptivity. The pore volume, particle size, and shape are not particularly limited, but the pore volume is 0.3 ml / g or more and the particle size is 50 mesh or less (particle diameter is about 0.3 mm or more) due to the relationship between the adsorption capacity of metal oxide and pressure loss. Is preferred.

The silica gel used in the present invention is an adsorbent produced by solidifying a silicic acid colloidal solution. The main component is silicon dioxide, which has a pore structure, has a specific surface area of 90 to 500 m ² / g, and exhibits high adsorptivity. The pore volume, particle size, and shape are not particularly limited, but the pore volume is 0.3 ml / g or more, and the particle size is
It is preferably 50 mesh or less (particle diameter of about 0.3 mm or more).

The zirconia used in the present invention is usually zirconium oxide obtained by heating zirconium hydroxide. During the sintering process of the powder, when transitioning from a monoclinic system to an orthorhombic system at 900 ° C, a few percent of the volume shrinks to form a porous material having a specific surface area of 100 to 200 m ² / g.
Zirconia sinter is used as a carrier because it has adsorptivity and has extremely high chemical stability. The properties of titanium oxide are almost the same.

Among these porous substances, activated carbon has a large specific surface area and thus has a large metal oxide carrying capacity, and since the surface is non-polar, it reacts with the metal oxide and its precursor to cause a chemical change. It is the most preferable as a carrier for metal oxides, since it has no fear, the deodorizing rate is fast due to its high adsorptivity for malodorous substances in the gas phase, and the deodorizing rate does not decrease even after long-term use.

The shape of these porous substances is not particularly limited, but, for example, in addition to granular or powdery forms, fibrous, honeycomb, sheet-like, cloth-like, felt-like or powdery porous substances can be used. It is possible to use one attached to urethane foam or the like, one having a honeycomb structure by corrugating a paper coated with a powdery porous material.

The metal atom contained in the metal oxide molecule may be a cerium atom alone, or a cerium atom and another metal atom may be contained at the same time. In this case, the types of other metals are not particularly limited, and a wide range of metals can be used. For example, it is one or more kinds of vanadium, manganese, copper, iron, molybdenum and the like.

The amount of cerium oxide added to the porous material is the metal content, and is preferably 100 parts by weight of the porous material.
It is 0.5 part or more, more preferably 1.0 part or more, preferably 30 parts or less, more preferably 10 parts or less. This is because if the amount of impregnation is less than 0.5 part, the catalytic action is poor, and if the amount of impregnation exceeds 30 parts, the adsorptivity of the porous material is impaired.

To prepare the metal oxide-impregnated porous material of the present invention, the precursor of the metal oxide is generally sprinkled as an aqueous solution on the porous material or by immersing the porous material. A predetermined amount is supported on the porous material. After that, the adhered liquid is separated, dried and heated to a predetermined temperature to be decomposed, so that the porous substance becomes a state in which the metal oxide is supported. For example, an aqueous solution of metal nitrate, ammonium ammonium salt or the like is adsorbed to the porous body by an adsorption method or a sprinkling method, and then this is heated to 100 ° C. or higher,
Preferably, by drying at 120 ° C. or higher, the nitrate or ammonium salt is thermally decomposed to produce a metal oxide, which is supported on the pores or microcracks of the porous material.

The isothiocyanate deodorant of the present invention can be obtained by further mixing activated carbon with the metal oxide-impregnated porous substance obtained above. Activated carbon is sometimes used as a carrier for metal oxides in the present invention, and is also used as a component of this deodorant as a simple substance of activated carbon. The specific surface area and other properties of this activated carbon are similar to those of the activated carbon used as a carrier for metal oxides.

[0025]

[Function] A deodorant obtained by mixing activated carbon with a composition in which cerium oxide or a composition in which cerium oxide and other metal oxides are impregnated on the surface of pores or microcracks of a porous substance is an isothiocyanate ester. The details of the mechanism for deodorizing the odor of are not clear. However, the trace amount of isothiocyanate vapor contained in the air
Isothiocyanic acid ester is adsorbed on the surface of the pores or microcracks of the porous material and activated carbon, and the adsorbability of the pore surface and the action of the cerium oxide molecule or other metal oxide molecule supported thereon are combined. It is considered that the molecule is decomposed into odorless components, and thus the deodorizing effect is considered to last for a long time.

In the examples described below, after the isothiocyanate was adsorbed on the deodorant, the amount of isothiocyanate contained in the gas produced by heating and desorption was measured, and the results are shown in Table 2. . When a cerium oxide or a porous substance supporting cerium oxide and other metal oxides and activated carbon is used as a deodorant, the amount of isothiocyanate ester contained in the desorption gas is extremely small, and the porous substance or activated carbon is used. It can be seen that the desorption gas contains a large amount of isothiocyanate in the case of only a single substance. Therefore, when supporting cerium oxide or cerium oxide and other metal oxides,
It shows a high degradability of isothiocyanates, but it is understood that the degradability of these esters is remarkably low when only the porous substance or activated carbon is used.

In the measurement result of the amount of isothiocyanate ester which is heated and desorbed after the adsorption of isothiocyanate vapor as described above, the cerium oxide of the present invention or the cerium oxide of the present invention and other metal oxides are supported as a deodorant. Also, when activated carbon is used, the amount of isothiocyanate contained in the desorption gas is extremely small. However, when only a metal oxide other than cerium oxide is supported on the porous material, cerium oxide or, as compared with the deodorant of the present invention supporting cerium oxide and other metal oxides, isothiocyanate ester It shows that the degradability is extremely low.

From these results, the action of the deodorant of the present invention depends on the adsorptivity of the porous substance and the activated carbon and the catalytic activity of the decomposition of the isothiocyanate ester by the synergistic action of the supported metal oxide such as cerium oxide. It seems that there is a lot to do.

The deodorant of the present invention is used for deodorizing isothiocyanate contained in gas, that is, isothiocyanate existing in vapor state in vapor phase. The type of isothiocyanate is not particularly limited, and it can be applied to a wide range of isothiocyanates.
Examples thereof include methyl isothiocyanate, ethyl isothiocyanate, allyl isothiocyanate, and phenyl isothiocyanate.

Among these, it is particularly suitable as a deodorant for allyl isothiocyanate used as a bactericide when storing home electric appliances in a warehouse.

[0031]

EXAMPLES The present invention will be described in more detail with reference to the following examples.

(Examples 1 to 8 and Comparative Examples 1 to 4) As the porous substance, crushed activated carbon having a particle size of 6 to 12 mesh obtained by steam activation of coconut shell carbide was used, and the results are shown in Table 1. After the metal oxide is impregnated with activated carbon, silica gel, activated alumina, granular zirconia or granular titania at the above content, the isothiocyanate deodorant (Examples 1 to 8) is mixed with a predetermined amount of non-impregnated activated carbon. Prepared. Also,
For comparison, a deodorant consisting only of non-impregnated activated carbon and an isothiocyanate deodorant consisting of activated carbon impregnated with a metal oxide other than cerium (Comparative Examples 1 to 4) were prepared.
The porous material to which the metal oxide was attached was prepared by immersing activated carbon or the like in an aqueous solution of the metal oxide precursor and attaching the porous material under the following preparation conditions, and then drying at 120 ° C. or higher to prepare a sample.

The composition of the deodorant obtained above is shown in Table 1.

[0034]

[Table 1]

Next, 1 g of each of the deodorizing agents shown in Table 1 was added.
It was taken, put in a glass bottle having a capacity of 3.9 l, degassed by a vacuum pump, and then 0.04 ml of allyl isothiocyanate solution was injected and vaporized. Next, after injecting air and returning to normal pressure, the initial concentration of allyl isothiocyanate was measured, and this was left in a thermostat at 25 ° C, and the concentration of allyl isothiocyanate after 24 hours was similarly measured. The removal rate of allyl isothiocyanate was calculated. Then, the sample was taken out, filled in a glass tube, and heated at 200 ° C. for 2 hours in a nitrogen stream to measure the amount of desorbed allyl isothiocyanate. Table 2 shows the results.

[0036]

[Table 2]

Next, an isothiocyanate deodorizing filter and an air cleaner were prepared using the isothiocyanate deodorant of the present invention. The isothiocyanate deodorizer used here was prepared in Example 1 and Comparative Example 1. FIG. 1 (a) is a sectional view of the isothiocyanate deodorizing filter of the present invention, and FIG.
Is an enlarged view of a part thereof. 1 is an isothiocyanate deodorizing filter main body, 2 is a kraft paper honeycomb substrate, the size of which is 25 mm in cell size, 7 mm in thickness, area
The amount of the isothiocyanic acid ester deodorant 3 is 0.120 m ² , and the filling amount is 300 g. 4 is a non-woven fabric, polyester,
Electret non-woven fabric made of thermoplastic resin fibers such as acrylic, polypropylene and polyethylene, and has some elasticity like cotton. The basis weight is 10 to 30 g / m ² , and the pressure loss is 0.5 mmAq or less when the wind speed is 1 m / sec.

As an adhesive sheet 5 for joining the honeycomb-shaped base material 2 and the non-woven fabric 4, a solventless type heat-fusible resin (polymer such as nylon or acrylic) is made into a fibrous shape,
In addition, a non-woven fabric having a high aperture ratio, that is, a so-called spider web sheet is used.

In order to assemble an isothiocyanate deodorizing filter, first, the honeycomb substrate 2 and the non-woven fabric 4 are bonded to each other on one side only by hot pressing using the spider web adhesive sheet 5, and then the isothiocyanate deodorant 3 is bonded. Spray evenly from above. Further, a spider web-shaped adhesive sheet 5 was placed thereon and heated by a hot press or the like to prepare a filter.

The isothiocyanate deodorizing filter thus obtained is used by incorporating it in an isothiocyanate deodorizing device 6 as shown in FIG. Reference numeral 7 is an air inlet, 8 is an air outlet, 9 is a control panel, and 10 is a filter mounting jig. FIG. 3 shows a horizontal sectional view of the isothiocyanate deodorizing device. The isothiocyanate deodorizing filter is shown in Fig. 3 by jig 10.
It is set like. 11 is a dust filter for removing coarse dust contained in the air, 12 is a motor,
13 is a fan and 14 is an air flow passage.

The isothiocyanate deodorizer thus obtained was placed in a box made of acrylic resin and having a capacity of 1 m ³ , and allyl isothiocyanate had an initial concentration of 30 p.
It was introduced into the acrylic box so that it would be pm. After that, the isothiocyanate deodorizer was operated at an air flow rate of 2.0 m ³ / min to measure the operation time and the residual amount of allyl isothiocyanate to prepare an adsorption decay curve. The results are shown in FIG.

The allyl isothiocyanate concentration is FTD.
(Flame Thermionic Detector) equipped high sensitive gas chromatograph.

According to the allyl isothiocyanate concentration decay curve shown in FIG. 4, the deodorant of the present invention shown in Example 1 has a higher endurance of allyl isothiocyanate adsorption capacity than the activated carbon alone of Comparative Example 1. I understand.

[0044]

The effect of the deodorant of the present invention is due to the adsorptive property of the porous material and the activated carbon and the catalytic interaction of the cerium oxide or other metal oxide supported on the porous material. Excellent adsorption and removal of odor of isothiocyanate in the phase. Particularly, it is suitable as a deodorant for allyl isothiocyanate, which is used as a bactericidal agent when storing household appliances and the like in a warehouse.

[Brief description of drawings]

FIG. 1A is a cross-sectional view of one embodiment of the isothiocyanate deodorizing filter of the present invention, and FIG. 1B is an enlarged view of a part thereof.

FIG. 2 shows a perspective view of one embodiment of the isothiocyanate deodorizing apparatus of the present invention.

FIG. 3 shows a horizontal sectional view of the isothiocyanate deodorizing device shown in FIG.

[Explanation of symbols]

 1 Filter Main Body 2 Honeycomb-like Substrate 3 Isothiocyanate Deodorant 4 Nonwoven 5 Adhesive Sheet 6 Isothiocyanate Deodorizer Main Body 7 Air Suction Port 8 Air Outlet 9 Control Panel 10 Filter Mount 11 Dust Filter 12 Motor 13 Fan 14 Air Flow passage

FIG. 4 shows the relationship between the operating time of the isothiocyanate deodorizer and the residual rate of allyl isothiocyanate.

[Explanation of symbols]

 15 Example 1 16 Comparative Example 1

Claims (4)

[Claims] 1. A deodorizer for isothiocyanate-containing gas, which is obtained by mixing activated carbon with cerium oxide or a porous substance impregnated with cerium oxide and other metal oxides. 2. The amount of cerium oxide attached to the porous material is 0.5 to 100 parts by weight of cerium oxide per 100 parts by weight of the porous material.
The deodorant for isothiocyanate-containing gas according to claim 1, which is 30 parts by weight. 3. The deodorizer for isothiocyanate-containing gas according to claim 1, wherein the porous substance is activated carbon. 4. A device for deodorizing a gas containing isothiocyanate, which comprises using a mixture of cerium oxide or a porous substance impregnated with cerium oxide and other metal oxides and activated carbon as a deodorant.