JPH11128668A - Deodorization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of such secondary malodors which emit uncomfortable smells by a chemical change of the materials adsorbed on deodorants having an oxidation decomposition function as time passes by passing malodorous gases or hazardous gases through a fore-stage deodorizing layer consisting of activated carbon, then through a post-stage deodorizing layer consisting of the deodorants described above. SOLUTION: In the case of a deodorization and purification treatments of malodorous gases or hazardous gases in an atmosphere of a dwelling space, etc., the coarse particles in the treating gases are removed by a filter 2 while the treating gases are introduced into an air cleaner by a fan 3 and, thereafter, the treating gases are passed through the fore-stage deodorizing layer 4 consisting of the activated carbon and are then passed through the post-stage deodorizing layer 5 consisting of the deodorants having the oxidation decomposition function, by which air purification is effected. While the activated carbon used for the fore-stage deodorizing layer 4 is not particularly limited, activated carbon of coconut shells, coal, timber, resins, etc., is exemplified. While the deodorant which is used for the post-stage deodorizing layer 5 and has the oxidation decomposition function is not particularly limited, for example, the powder or moldings of a catalyst having the oxidation decomposition function or carries carried with the catalyst components are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deodorizing method which does not easily emit odor even in a high humidity environment.

[0002]

2. Description of the Related Art Various odorous or harmful gases (hereinafter referred to as odorous gases) in the atmosphere of a living space of a general household, a cabin of an automobile or the like, a workshop of a factory, and the like are deodorized and purified by an adsorption treatment or a chemical treatment. Many air purifiers have been developed and used. Conventionally, in the physical deodorization method, adsorbents such as activated carbon, zeolite, silica gel, and alumina have been widely used as deodorants. Also, a method of catalytically decomposing odor gas using an oxidative decomposition catalyst is widely used. A deodorization method combining physical deodorization and chemical deodorization has also been developed. However, if the deodorant is used for a relatively long period of time, especially in a high-humidity environment, unpleasant odor is caused by the problem of odor caused by the odor of the deodorant itself, and unpleasant odor due to chemical change of the odorant adsorbed by the deodorant. Issue arises.

[0003] Activated carbon has long been used as a deodorant for adsorbing and removing harmful components in odorous gas, and the types and shapes of activated carbon suitable for many deodorizing treatments have been studied and developed. For example, Japanese Unexamined Patent Publication (Kokai) No. 60-135061 discloses an adsorption type deodorant having physical adsorption capacity selected from powdered substances such as activated carbon and zeolite and ion exchange resins, a vegetable oil component, an aliphatic dialdehyde, and an iron ion + L. -A sponge-like deodorizing agent characterized by including a reactive deodorizing agent having a chemical reaction-type deodorizing ability such as ascorbic acid in an open-cell foam is disclosed. It is described that a synergistic effect of deodorization is obtained by combining a reaction adsorption effect of a liquid reactive deodorant in addition to a deodorizing effect of a liquid type deodorant, and an extremely high deodorizing effect is obtained.

Activated carbon is also widely used as a pretreatment agent for preventing adsorbents, catalysts and the like from being damaged by harmful substances.
No. 177 discloses a method for adsorbing and recovering a solvent in an exhaust gas using an activated carbon adsorption method. In the method, exhaust gas from which coarse particles have been removed is passed through a fine filter and an activated carbon preliminary layer, and then pores having an average pore diameter of 50 ° are removed. Through the porous activated filler layer having, and by performing adsorption with activated carbon rich in macropores using ordinary activated carbon, the exhaust gas containing impurities in the gaseous or particulate form that lowers the adsorbing ability of the adsorbent at the subsequent stage is removed from the exhaust gas. A method for efficiently recovering a solvent without reducing the adsorbing ability of an adsorbent is disclosed.

As described above, various techniques have been developed to improve the deodorizing ability by combining various activated carbons, or to pretreat substances that are inconvenient for the subsequent treatment or inhibit the function of the latter by using activated carbon. I have. However, there is no teaching or suggestion in these prior art documents to solve the problem that the deodorant emits odor due to a change with time and environment.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a primary odor caused by adsorption of an odor gas by a deodorant and an unpleasant odor due to a chemical change of a substance adsorbed by the deodorant over time. It is an object of the present invention to provide a novel deodorizing method that prevents generation of a secondary odor that is generated.

[0007]

SUMMARY OF THE INVENTION The present inventors have developed a primary odor caused by the adsorption of an odor gas by a deodorant and an unpleasant odor due to a chemical change of a substance adsorbed on the deodorant over time. In order to prevent the generation of secondary odors, we conducted various studies and conducted intensive studies.As a result, we decided to use an adsorbent mainly composed of activated carbon and other deodorants with oxidative decomposition functions in a specific order of use. By using in combination, the effective period of the deodorant was dramatically extended, and it was found that it was difficult to emit odor even in a high humidity environment. The present invention has been made based on the above findings.

[0008] That is, the present invention relates to a deodorization method characterized in that after passing through a pre-deodorization layer made of activated carbon, it is passed through a post-deodorization layer made of a deodorant having an oxidative decomposition function.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the deodorizing method of the present invention, a processing gas is introduced into an air purifier by an air introducing means such as a fan.
Preferably, first, after removing coarse particles such as mist and dust in the processing gas by a filter, the filter is passed through a pre-stage deodorizing layer made of activated carbon provided on the upstream side, and then provided with a deoxidizing function having an oxidative decomposition function provided on the downstream side. Air purification is carried out by passing through a second-stage deodorizing layer made of an agent.

The type of the air introduction means is not limited, as long as it can introduce the processing gas into the air purifier.

There is no particular limitation on the filter for removing coarse particles in the processing gas. For example, a particulate filter such as soot, mist or dust in the processing gas or tar, etc., is filtered by a usual filter made of glass wool or the like. Can be physically removed.

The activated carbon used in the pre-deodorization layer disposed upstream of the air purifier according to the deodorization method of the present invention is not particularly limited as long as it is a material that functions as an adsorbent. The performance of activated carbon often depends on its raw material, but raw materials of activated carbon include coconut shell, coal, wood, pitch, resin, and the like, and can be appropriately selected according to the purpose and use of the activated carbon. The shape of the activated carbon is not particularly limited, and powdered, crushed, columnar, pelletized, etc., activated carbon, honeycomb-shaped activated carbon, fibrous activated carbon, felt, thread, woven, paper What was processed into the shape can be used. Honeycomb activated carbon has a low pressure loss and is suitable for treating large amounts of gas.Fibrous activated carbon has a significantly improved adsorption / desorption speed compared to granular activated carbon, and has a large amount of adsorption at a low concentration. is there.

However, since activated carbon is hydrophobic and has very poor polarity, it has the property of selectively adsorbing bad odors from non-polar molecules, for example, solvent odors such as benzene and toluene, even in high humidity environments. However, on the other hand, polar molecules such as ammonia, amines or aldehydes are hardly adsorbed and the adsorption speed is slow.For example, even if a smoking odor is passed through activated carbon, a pungent odor such as ammonia or a malodor such as acetaldehyde is generated. Leaks out.

The deodorant having an oxidative decomposition function, which will be described later, reacts with any odor component or organic substance in the processing gas, although it cannot be specified particularly in a high humidity environment,
It is believed that they cause a chemical change on the deodorant to produce odorants with very low olfactory thresholds. That is, it is considered that the deodorant having the oxidative decomposition function generates an unpleasant odor due to the odor substance generated secondarily, and causes a new factor of the generation of an unpleasant odor.

In view of the above, the present invention aims to adsorb and remove these causative substances or chemically change them by activated carbon disposed upstream thereof.

The deodorizing agent having an oxidative decomposition function used in the latter deodorizing layer disposed downstream of the air purifier according to the deodorizing method of the present invention is a deodorizing agent capable of oxidatively decomposing odor gas. There are no particular restrictions. The deodorant having an oxidative decomposition function may be, for example, a catalyst powder having a oxidative decomposition function, a molded product, or a carrier having a catalyst component supported thereon.

The carrier is not particularly limited, but it is preferable to use a porous carrier, which is generally a carrier through which a reaction gas can flow and has a small pressure loss. For example, inorganic carriers such as cordierite, alumina, silica alumina, titania silica, zeolite, sepiolite, and a zeolite-sepiolite mixture are suitable. The shape of the carrier may be a honeycomb shape, a sponge shape, a mat shape, a woven fabric shape, a plate shape, a cylindrical shape, a granular shape, or the like. The structure is preferable because it has a low pressure loss and is suitable for processing a large amount of gas. The cell shape of the honeycomb is arbitrary, and may be a polygonal shape such as a triangle, a square, a pentagon, or a hexagon, or a shape such as a corrugated shape. For example,
An aggregate of ceramic fibers as proposed in JP-A-9-15028 (a honeycomb carrier manufactured by Nichias), that is, silica fibers bonded to each other by a silicate gel;
A honeycomb structure formed by laminating a sheet-like aggregate of ceramic fibers selected from inorganic fibers such as alumina fibers, aluminosilicate fibers, and zirconia fibers in a honeycomb shape has a low pressure loss and a large geometric surface area. It is particularly preferable because it has a high water content and can support a large amount of the active ingredient.

The catalyst component is not particularly limited as long as it can oxidatively decompose odor gas. Preferred catalyst components are platinum group elements consisting of rhodium, palladium, ruthenium, iridium and platinum;
Transition metal elements composed of iron, cobalt, chromium and nickel; group I elements such as copper and silver; group VII elements such as manganese; group II elements such as zinc, and rare earth metals such as cerium and lanthanum. . One of these metals or a suitable combination thereof is used as a catalyst component. The catalyst component can be used in the form of an elemental metal, its oxide or a complex, and is used by being supported on a carrier by a conventional method such as an impregnation method, a slurry method, a wash coat method, or the like.

Those obtained by subjecting these metal ions to ion exchange treatment with zeolite can be suitably used. For example, ion exchange Y-type zeolite with a basic odor component such as amines such as ammonia, dimethylamine and trimethylamine, and a copper component having a particularly effective deodorizing performance against malodorous components such as hydrogen sulfide and methyl mercaptan. The deodorant in combination with the hydrophobic silicalite, which is particularly excellent in the adsorption performance for aldehyde and dimethyl sulfite, has an excellent deodorizing effect and is not easily affected by the humidity in the atmosphere. It is a deodorant.

The amount of the catalyst component to be carried varies depending on the catalyst component used and the malodorous gas component to be treated.
In the case of a platinum group element, 0.1 to 10 g / liter, preferably 0.5 to 5 g / liter, and more preferably 1 to 5 g / liter.
2 g / liter, and in the case of other base metal elements, 10 to 100 g / liter, preferably 20 to 70 g / liter.
g / liter, more preferably 30 to 50 g / liter. When a rare earth metal is used in combination, the rare earth metal is supported at 1 to 100 g / l, preferably 5 to 20 g / l.

The deodorizing agent having an oxidative decomposition function used in the latter deodorizing layer of the air purifier is preferably one capable of efficiently oxidatively decomposing and removing polar molecules such as ammonia, amines and aldehydes which are difficult to adsorb and remove with activated carbon. .

Next, the deodorizing method of the present invention will be described with reference to FIG. The processing gas enters the filter 2 from the line 1 by the fan 3, and removes particulate impurities such as soot, mist, dust, etc. in the processing gas and dusts, and passes through the former deodorizing layer 4 made of activated carbon. The odor components contained in the odor and the components that are not clearly identified but are converted to off-flavor components by a chemical reaction with a deodorizing agent having an oxidative decomposition function in the later deodorizing layer are adsorbed and removed, and then the deodorant having an oxidative decomposition function Through the second deodorizing layer 5 composed of the agent,
Here, the offensive odor components that have not been adsorbed and removed by the activated carbon of the former deodorizing layer are oxidatively decomposed by the deodorant, or are adsorbed and removed by the latter deodorizing layer, and the purified processing gas is discharged from the line 6.

[0023]

The present invention will be described below in more detail with reference to Examples, Comparative Examples and Test Examples. However, the present invention is not limited at all by these examples.

EXAMPLE 1 A square cell having a cell density of 5 per square inch
00 cell honeycomb activated carbon manufactured by Kyocera (brand name: AB
165, containing 65% by weight as activated carbon) were molded to a size of 75 mm in length, 75 mm in width, and 20 mm in thickness to prepare a first-stage deodorized layer A.

117 g of a manganese nitrate solution (containing 50% by weight as Mn (NO ₃ ) ₂ ) manufactured by Tanaka Chemical Co., Ltd.
Of copper nitrate crystal {Cu (NO ₃ ) ₂ .3H ₂ O}, and further diluted with 208 g of ion-exchanged water to obtain 10.0% by weight of manganese nitrate in terms of Mn and Cu. To prepare a manganese nitrate / copper nitrate aqueous solution containing 3.3% by weight of copper nitrate.

In 44 parts by weight of ion-exchanged water, a pentasil-type zeolite (UO having a silica / alumina molar ratio of 250) was used.
Company P, trade name: silicalite S-115) 24 parts by weight, Y-type zeolite (silica / alumina, molar ratio of 6 manufactured by UOP, trade name: LZY84) 12 parts by weight, and Al
Alumina sol 2 containing 20% by weight of alumina in terms of ₂ O ₃
And 0 parts by weight, and mixed and pulverized for 8 hours using a wet ball mill to prepare a slurry.

[0027] To this slurry, 75mm x 75mm x,
Nichias corrugated honeycomb carrier (trade name: 600 cells per square inch) constituted by laminating in a honeycomb shape a sheet-like aggregate of ceramic fibers bonded to each other by a silicate gel having a thickness of 20 mm. : Honeycomb) was immersed, pulled up, and the excess slurry was removed by blowing air, dried at 150 ° C. for 1 hour, and fired at 400 ° C. for 1 hour.

The baked corrugated honeycomb carrier is immersed in the manganese nitrate / copper nitrate aqueous solution, pulled up,
After blowing excess air to remove excess aqueous solution,
After drying for 1 hour at a temperature of 400
C. for another 1 hour at a temperature of 100 ° C., and 100 g of silicalite, 50 g of Y zeolite,
7 g of alumina, 38 g of active manganese oxide in terms of MnO ₂ , and 10 g of active copper oxide in terms of CuO were supported, to prepare a deodorizer X for the subsequent stage.

Diameter 80 mm x 80 mm, length 150 mm
Gas flow type box-deodorizing tester daily average 30 pieces of 42m ³ room cigarette is smoked (temperature 25 ° C., relative humidity 5
0%). A first-stage deodorizing layer A was installed at the inlet side of the deodorizing tester, a second-stage deodorizing agent X was installed behind the former, and air was continuously circulated through the variable-speed sirocco fan at a wind speed of 1 m per second for 4 weeks. After the room temperature reaches 30
After adjusting the temperature and the relative humidity to 70% and operating again in the state of smoking for three days, the odor intensity at the outlet side of the deodorization tester was measured and evaluated by six persons using a six-point evaluation method. Table 1 shows the results of the average evaluation.

Example 2 A 20 mesh stainless steel wire mesh container having a size of 80 mm in length, 80 mm in width and 20 mm in thickness is filled with granular activated carbon (trade name: Taiko TG) manufactured by Nimura Chemical Co., Ltd. Was formed. An evaluation test was conducted on the odor intensity on the outlet side of the deodorization tester in the same manner as in Example 1 except that the predeodorization layer B was installed instead of the predeodorization layer A in Example 1, and the results of the average evaluation Are shown in Table 1.

Example 3 A deodorizing filter manufactured by Kuraray (product number: #) in which activated carbon powder was kneaded and impregnated into a polyurethane foam having a thickness of 10 mm.
2000) was cut out into a size of 75 mm in length and 75 mm in width, and two of them were stacked to obtain a pre-stage deodorized layer C. An evaluation test was conducted on the odor intensity on the outlet side of the deodorization tester in the same manner as in Example 1 except that the predeodorization layer C was installed instead of the predeodorization layer A in Example 1, and the results of the average evaluation Are shown in Table 1.

Example 4 36 parts by weight of pentasil-type zeolite (manufactured by UOP having a silica / alumina molar ratio of 250, trade name: silicalite S-115) and 44 parts by weight of ion-exchanged water and Al ₂ O ₃
20 parts by weight of an alumina sol containing 20% by weight of alumina were added and mixed for 8 hours using a wet ball mill.
The slurry was prepared by grinding. 75m to this slurry
The same Nichias corrugated honeycomb carrier as used in Example 4 having a size of mx 75 mm x thickness of 20 mm was immersed and pulled up, and excess slurry was removed by blowing air. Dry for an additional 40 hours
Baking was performed at a temperature of 0 ° C. for 1 hour. The fired corrugated honeycomb carrier was impregnated with the same aqueous solution of manganese nitrate and copper nitrate as in Example 1 to obtain a 150 g / l deodorant.
g of silicalite, 17 g of alumina and 38 g of activated manganese oxide in terms of MnO ₂ and 10 in terms of CuO.
A second stage deodorizer Y supporting g of active copper oxide was prepared.

The odor intensity at the outlet of the deodorization tester was evaluated in the same manner as in Example 1 except that the latter-stage deodorizing layer Y was provided instead of the latter-stage deodorizing layer X, and the average evaluation was performed. Table 1 shows the results.

Example 5 18 parts by weight of pentasil-type zeolite (manufactured by UOP having a silica / alumina molar ratio of 250, trade name: silicalite S-115) and 44 parts by weight of ion-exchanged water and hopcalite powder (Toyo) CCG, product name KCG-1P) 1
8 parts by weight and 20 parts by weight of silica sol containing 20% by weight of silica in terms of SiO ₂ were added, and mixed and dispersed using a turbo mixer for 8 hours to prepare a slurry. In this slurry, a Nichias corrugated honeycomb carrier similar to that used in Example 4 having a size of 75 mm × 75 mm × 20 mm in thickness was immersed and pulled up, and excess slurry was blown with air to remove the slurry. Dried for 1 hour at a temperature of 75 g of silicalite per liter of deodorant,
Second-stage deodorant Z was prepared by supporting 75 g of hopcalite and 17 g of silica.

The odor intensity on the outlet side of the deodorizing tester was evaluated and evaluated in the same manner as in Example 1 except that the latter deodorizing layer Z was provided in place of the latter deodorizing layer X, and the average evaluation was performed. Table 1 shows the results.

COMPARATIVE EXAMPLE 1 A deodorizing test apparatus was prepared in the same manner as in Example 1 except that the latter-stage deodorizing layer X of Example 1 was provided on the inlet side, and the former-stage deodorizing layer A of Example 1 was provided behind the latter. An evaluation test was conducted on the odor intensity on the outlet side, and the results of the average evaluation are shown in Table 1.

COMPARATIVE EXAMPLE 2 A deodorizing test apparatus was prepared in the same manner as in Example 1 except that the latter-stage deodorizing layer X of Example 1 was provided on the inlet side, and the latter-stage deodorizing layer X of Example 1 was also provided behind the latter. The evaluation test was conducted on the odor intensity on the outlet side of the sample, and the results of the average evaluation are shown in Table 1.

Comparative Example 3 The odor intensity on the outlet side of the deodorization tester was measured in the same manner as in Example 1 except that the former deodorizing layer A was provided instead of the latter deodorizing layer X as the latter deodorizing layer. The evaluation test was conducted, and the results of the average evaluation are shown in Table 1.

[0039]

[Table 1]

6-step odor intensity evaluation 0: odorless 1: odor finally detectable (detection threshold density) 2: weak odor (recognition threshold density) that tells what odor is 3: odor easily detectable 4: strong odor 5 : Strong smell

As is clear from Table 1, in the present invention, the former deodorizing layer made of activated carbon was provided on the inlet side of Examples 1 to 5, and the latter deodorizing layer was made of the deodorizing agent having an oxidative decomposition function on the outlet side. The odor intensity of the outlet by the deodorizing method is much lower than that of Comparative Example 1 in which a deodorizing agent having an oxidative decomposition function is provided upstream and a deodorizing layer made of activated carbon is provided downstream. It turns out that it is hard to generate a bad smell. That is, the deodorizing treatment is not simply performed by the activated carbon and the deodorizing agent having the oxidative decomposition function, but the processing gas is first passed through the former deodorizing layer made of the activated carbon, and then the deodorizing agent having the oxidizing decomposition function. For the first time, it was proved that an unpleasant odor was unlikely to be generated at the entrance side by passing through a deodorizing layer consisting of. Further, the odor intensity at the outlet by the deodorizing method of the present invention was determined in Comparative Example 2 in which a deodorizing agent having an oxidative decomposition function was disposed both upstream and downstream, and Comparative Example 3 in which a deodorizing layer made of activated carbon was disposed both upstream and downstream. In comparison with the odor intensity of the outlet by the deodorizing method, it can be seen that the deodorizing method of the present invention hardly generates an unpleasant odor. In the case of Example 2, since the activated carbon was kneaded into the polyurethane foam and impregnated, the proportion of the activated carbon exposed on the surface was small, and the proportion of the exposed polyurethane foam itself was large. Is easy to adhere, odor release from the attached mist,
It is probable that the emission odor intensity of the outlet was higher than that of the other substances because the amount of odor adsorbed by the attached dust was large. In other words, the deodorization method of the present invention, in which the treatment gas is first passed through the activated carbon, is passed through the pre-deodorization layer made of activated carbon, and then passed through the latter deodorization layer made of a deodorizer having an oxidative decomposition function. Although it is not possible to identify any of the gases, it is possible to adsorb and remove or chemically change the substances that cause chemical changes on the deodorant and generate odorous substances. It was confirmed that the emission of off-flavor was not very low.

[0042]

After passing through the former deodorizing layer made of activated carbon,
By passing through the post-deodorizing layer consisting of a deodorizing agent with oxidative decomposition function, even when deodorizing for a long period of time or even in a high-humidity environment, the emission of off-odors can be extremely reduced, and replacement and regeneration of the deodorizing agent Can be greatly extended.

[Brief description of the drawings]

FIG. 1 is a flow sheet for explaining a deodorizing method of the present invention.

[Explanation of symbols]

 1 line 2 filter 3 fan 4 front deodorization layer 5 rear deodorization layer 6 line

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshiya Nashida 1212 Shinomiya, Hiratsuka-shi, Kanagawa Prefecture JGC Universal Corporation

Claims (1)

[Claims] 1. After passing through a pre-deodorization layer made of activated carbon,
A deodorizing method characterized by passing through a second deodorizing layer comprising a deodorizing agent having an oxidative decomposition function.