JPH0642899B2 - Deodorant for sulfur compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field] The present invention is directed to the adsorption of sulfur compounds such as sulfur malodorous substances such as hydrogen sulfide, mercaptans, methyl sulfide and methyl disulfide in the atmosphere or gas and sulfur oxides. The present invention provides a deodorant for sulfur compounds, which is excellent in adsorption ability especially at room temperature and dry type.

[Conventional technology]

The presence of sulfur-based malodorous substances and sulfur compounds such as sulfur oxides in the atmosphere and gas has become a social problem as pollution.

Especially, bad odor not only makes living environment uncomfortable, but also "Hospital equipment" (Vol.27, No.6, 1985), page 505, "... on the effects on the body ... Respiratory system, There are effects on the function of each organ such as the digestive system, reproductive system, endocrine system, and the mental state .... ”As described above, it is a serious problem affecting health.

In addition, a large amount of exhaust gas is being emitted due to the increase of combustion furnaces and the spread of automobiles with the development of industry in recent years, and various exhaust gas countermeasures have been adopted.

As is well known, as the deodorizing method, there are a washing method using an alkaline aqueous solution, a direct combustion method, a catalytic oxidation method, an adsorption method and the like. However, the cleaning method using an alkaline aqueous solution is difficult to process and maintain the deodorizing waste liquid, and the direct combustion method and the catalytic oxidation method are
This is not an advantageous method because it requires a large amount of air to be burned at a high temperature and also requires treatment of sulfur dioxide gas generated.

Against these, an adsorption method that is relatively simple and can be used at room temperature is drawing attention, and there is a strong demand for the development of a deodorant having excellent adsorption ability for sulfur compounds such as sulfur malodorous substances and sulfur oxides in gases. ing.

Activated carbon, silica gel, zeolite, iron oxide and the like have been conventionally known as deodorants.

[Problems to be solved by the invention]

It has been pointed out that the above-mentioned known deodorizers have insufficient adsorbing ability for sulfur-based malodorous substances such as hydrogen sulfide, mercaptan, methyl sulfide and methyl disulfide, and sulfur compounds such as sulfur oxides.

This fact is, for example, the "Fragrance Journal"
(No.72, 1985) Page 75, “…… For general-purpose activated carbon ……
It has low adsorption capacity for acidic gases such as hydrogen sulfide and mercaptan, and neutral gases such as methyl sulfide and aldehyde. ...... Silica / alumina-based adsorbents other than activated carbon have an affinity for odorants with strong basicity or polarity, but the adsorption of odorants is hindered by the stronger adsorption of water entrained in the gas. . Zeolite also has different adsorption affinities for a wide variety of odor molecules depending on the size of the molecule, but in the presence of water, deodorization is disturbed as in the former case. ...... "or" Chemical Society of Japan "published by the Chemical Society of Japan (1978), p. 665," Inorganic compounds such as activated carbon and various metal oxides have been studied to adsorb and remove sulfur dioxide. " However, there are still problems with the adsorption capacity, selectivity, regeneration method, etc., and the development of new adsorbents is desired. ”

On the other hand, it is known that ferric oxide hydroxide particles have excellent adsorption ability for sulfur compounds such as sulfur malodorous substances and sulfur oxides.

This fact is, for example, published by the Chemical Society of Japan "Chemical Society of Japan"
(1980) Page 681 “... Since we found that hydrous iron oxide has a high ability to chemisorb SO ₂ , it is close to the combustion furnace exhaust gas composition for the purpose of examining its potential as an SO ₂ adsorbent material. We conducted SO ₂ adsorption experiments from a mixed gas, and learned that SO ₂ adsorption capacity had almost no effect of coexisting H ₂ O.
... "is as described.

Incidentally, as prior art documents using the ferric oxide hydroxide particles as a deodorant for sulfur compounds, there are JP-B-46-20688 and JP-A-50-60492.

By the way, since the deodorant adsorbs sulfur compounds such as sulfur-based malodorous substances and sulfur oxides on the surface of the deodorant, the larger the specific surface area of the deodorant, the higher the adsorption capacity, and thus the deodorant can be formed. Only fineness is required.

This fact is because, for example, in the study of gas molecule adsorption on a solid surface, a powder having a large surface area is often used in "Chemical Society of Japan" (1980) p. ... "is as described.

Therefore, as a deodorant for adsorbing sulfur compounds such as sulfur-based malodorous substances and sulfur oxides, in order to further improve the adsorption ability of ferric oxide hydroxide particles, particularly the adsorption ability during use at room temperature and dry type, There is a strong demand for making fine particles of particles.

However, in the case of needle-shaped ferric oxide hydroxide particles, in particular, the finer the particles are, the more particles stick to each other and agglomerate with each other. There is a problem in that the permeability becomes poor, the contact area with a sulfur-based malodorous substance in the air or gas or a sulfur compound such as sulfur oxide becomes small, and the adsorption ability decreases.

In addition, the pure γ-iron oxyhydroxide particles powder and the urchin-shaped ferric oxide hydroxide particles shown in the above publications are considered to have excellent sulfur compound adsorption ability due to the particle morphology. I can't.

[Means for solving problems]

The present inventor, as a technical problem to solve the above problems, in order to improve the adsorption capacity of the ferric oxide hydroxide particles, the specific surface area of the ferric hydroxide particles powder and the contact area with the atmosphere or gas, etc. The present invention has been achieved as a result of repeated systematic examinations and studies of the above.

That is, the present invention has a bamboo-like hydrous second oxide having a stripe-shaped ultrafine structure and having a major axis diameter of 0.2 to 1.0 μm and an axial ratio (major axis diameter / minor axis diameter) of 3 to 10. A deodorant for sulfur compounds, which is composed of iron particle powder.

[Action]

First, the most important point in the present invention is that the axial ratio (major axis diameter / major axis diameter) is 0.2 to 1.0 μm, which has a stripe-shaped ultrafine structure.
(Short axis diameter) 3 to 10 leaves of bamboo hydroxide-like ferric oxide particles are used as a deodorant, due to their large specific surface area and large contact area with the atmosphere and gas. Then, it is a fact that the adsorption of sulfur compounds such as sulfur-based malodorous substances and sulfur oxides in the air or gas can be efficiently carried out, particularly when used at room temperature and dry type.

The ferric hydroxide-containing fine particle powder used in the present invention is a bamboo grass having a streaky ultrafine structure and a major axis diameter of 0.2 to 1.0 μm and an axial ratio (major axis diameter / minor axis diameter) of 3 to 10. Since the particles are leaf-shaped, the specific surface area is extremely large.

Furthermore, the hydrous ferric oxide fine particles used in the present invention,
Since the particles have a bamboo leaf shape and are rounded, particles are less likely to stick to each other and overlap each other, and have a large porosity and good air permeability, and thus have a large contact area with the atmosphere and gas.

That is, the ferric oxide hydroxide fine powder used in the present invention,
Due to its large specific surface area and large contact area with air and gas, it is possible to efficiently adsorb sulfur compounds such as sulfur malodorous substances and sulfur oxides in air and gas, and to deodorize It is extremely excellent as an agent.

The deodorant of the present invention may be used as it is by granulating it into powder or pellets, or by mixing or coating it on paper, cloth, etc., and molding it into a honeycomb structure or laminate structure for use. You can also Further, it can be attached to a substrate having a honeycomb structure or a laminated structure and used as a deodorizing filter.

Bamboo leaf-shaped ferric oxide-containing ferric oxide fine powder of the following "Example 1", acicular hydrous ferric oxide fine-particle powder of the following "Comparative Example 1", and porridge-shaped hydrous hydroxide-containing fine powder of the following "Comparative Example 2". The experimental results of measuring the hydrogen sulfide adsorption capacity of the diiron particle powder are shown as experimental examples.

Experimental Example 1 Each of the ferric oxide hydroxide particles was pressure-molded and crushed to obtain a sample having a uniform particle size of 10 to 20 mesh. Set it on an evaluation device (Evaluation method described in “Chemical Industry Data”, Vol. 20, No. 4, (1985) page 14), and then put a tedra bag containing 10 l of a test gas containing hydrogen sulfide at a concentration of 5 ppm into the device. Attached to. Subsequently, the test gas was circulated by ventilating the sample column at a flow rate of 5 l / min. The circulating test gas is sampled at regular intervals, and the concentration of hydrogen sulfide contained in the sampled test gas is measured by gas chromatography.

From FIG. 1, the bamboo-leaf-shaped ferric hydroxide-containing fine particles (curve A in the figure) of “Example 1” described later are the acicular hydrous ferric-oxide fine particles of “Comparative Example 1” (see the figure). It can be confirmed that the adsorption performance of hydrogen sulfide is superior to that of the curve B) of No. 1 and the urchin-shaped ferric oxide hydroxide particles (curve C in the figure) of Comparative Example 2 described later.

Experimental Example 2 Each of the above-mentioned powders of ferric oxide hydroxide was tested in Experimental Example 1
Similar to the above, a sample that has been sized to 10 to 20 mesh is used,
The column was filled with g and set in a flow-through type adsorption capacity evaluation device (Kodansha Scientific published "Catalysis Experiment Handbook" (Catalysis Society of Japan) (1986), page 44), and then a concentration of 10 ppm Test gas containing hydrogen sulfide 1l / min
The sample column was vented at a rate of. The test gas that has passed through the sample column is sampled at regular intervals, and the concentration of hydrogen sulfide contained in the sampled test gas is measured by gas chromatography.

From FIG. 2, the bamboo-leaf-shaped ferric hydroxide-containing fine particles of the bamboo (curve A in the figure) of “Example 1” described later are the needle-shaped ferric-hydroxide-containing fine particles of the powder of “Comparative Example 1” (see the figure). It can be confirmed that the adsorption capacity of hydrogen sulfide is larger than that of the curve B) of No. 1 and the urchin-shaped ferric oxide hydroxide particles (curve C in the figure) of Comparative Example 2 below.

Next, various conditions for carrying out the present invention will be described.

The ferric hydroxide-containing fine particle powder used in the present invention has a striped ultrafine structure, has a length of 0.2 to 1.0 μm, and has an axial ratio (major axis diameter / minor axis diameter) of 3 to 10 It is a powder consisting of ferric oxide hydroxide particles exhibiting the above.

Particles having a major axis diameter of more than 1.0 μm are unsuitable because they have a small specific surface area, and particles having a major axis diameter of less than 0.2 μm are undesirably agglomerated between particles because they are too fine.

In addition, particles with an axial ratio of less than 3 have a smaller characteristic that the particles have a bamboo-like shape with a stripe-shaped ultrafine structure, and particles with an axial ratio of more than 10 have a needle-like shape. It is not preferable.

The ferric oxide hydroxide fine particle powder used in the present invention can be easily obtained by the following production method.

That is, 1 equivalent or more of an aqueous solution of an alkali carbonate with respect to the ferrous salt is added to the ferrous salt aqueous solution and reacted to obtain FeCO ₃ , and an oxygen-containing gas is passed through the obtained suspension containing FeCO ₃ . Then, it is obtained by an oxidation reaction.

In the above production method, as the aqueous ferrous salt solution, an aqueous ferrous sulfate solution, an aqueous ferrous chloride solution, or the like is used. When an aqueous solution of ferrous salt or an aqueous solution of alkali carbonate or an alkali hydroxide is added to an aqueous solution of ferrous salt to obtain FeCO ₃ or Fe-containing precipitate, a part of the alkali carbonate is treated with alkali hydroxide within a range of 50% or less with respect to the alkali carbonate. You may replace and use it.
As the alkali carbonate, sodium carbonate, potassium carbonate, ammonium hydrogen carbonate or the like is used alone, or when these are used in combination with alkali hydroxide, sodium hydroxide, potassium hydroxide, ammonium hydroxide or the like is used. . Further, in some cases, it may be aged under a non-oxidizing atmosphere.

The pH of the solution during the oxidation reaction is 7-11. When the pH is less than 7 or more than 11, the bamboo-leaf-shaped ferric oxide hydroxide particles cannot be obtained.

The reaction temperature during oxidation is 30 to 80 ° C. Below 30 ° C, bamboo-leaf-shaped ferric oxide hydroxide particles cannot be obtained, and above 80 ° C, granular black precipitates are mixed.

The oxidizing means is performed by aerating an oxygen-containing gas (for example, air) in the liquid, and is performed while stirring by the aeration gas or mechanical operation.

〔Example〕

Next, the present invention will be described with reference to Examples and Comparative Examples. The particle diameters and axial ratios (major axis diameter / minor axis diameter) in the following examples and comparative examples are all shown as the average value of the numerical values measured from electron micrographs, and the specific surface area is measured by the BET method. It was shown by the value. Also, the adsorption performance of hydrogen sulfide is
It is the value evaluated by the method of the above-mentioned Experimental Example 1, and the adsorption capacity of hydrogen sulfide is the value evaluated by the method of the above-mentioned Experimental Example 2.

Example 1 20 l of a 3.53 mol / l aqueous solution of NaCO ₃ was placed in a reaction vessel, and then 30 l of a 1.0 mol / l aqueous solution of FeSO ₄ was added and mixed to obtain a temperature of 4
FeCO ₃ was obtained at 0 ° C. At a temperature of 40 ° C., 150 l of air per minute was passed for 4.0 hours in the obtained aqueous solution containing FeCO ₃ to carry out an oxidation reaction to generate yellowish brown precipitate particles.
The pH of the reaction solution during aeration with air was 9.6.

The produced yellowish brown precipitate particles were separated, washed with water, dried and pulverized by a conventional method to obtain 2.61 kg of yellowish brown particle powder.

As a result of X-ray diffraction, the obtained yellowish brown particle powder could be confirmed to be hydrous ferric oxide. The result is shown in FIG.
Also, the obtained yellowish brown particle powder is an electron micrograph (× 30,000) shown in FIG. 4 and an enlarged photograph (× 15) shown in FIG.
(0,000), the average value of the major axis diameter is 0.25 μm, the axial ratio (major axis diameter / minor axis diameter) is 8, and the surface area is 106 m ² / g. It was confirmed that the particles were composed of ferric oxide hydroxide particles.

The adsorption performance of hydrogen sulfide of the bamboo leaf-shaped ferric oxide hydroxide particles as described above, the concentration of the test gas after aeration for 15 minutes is 0.16 ppm,
The adsorption capacity is such that the concentration of the test gas after aeration for 120 minutes is 0.2.
It was 0 ppm.

Comparative Example 1 80 l of 0.68 mol / l FeSO ₄ / g aqueous solution was placed in a reaction vessel, then 10 l of 4.32 mol / l NaOH aqueous solution was added and mixed, and subsequently, at a temperature of 40 ° C., a rate of 130 l / min. The reaction was carried out for 4 hours while air was blown through to produce yellowish brown precipitate particles. The pH of the reaction solution during aeration was 5.8 to 4.0.

The produced yellowish brown precipitate particles were separated, washed with water, dried and pulverized by a conventional method to obtain 1.83 kg of yellowish brown particle powder.

As a result of X-ray diffraction, the obtained yellowish brown particle powder could be confirmed to be hydrous ferric oxide. The result is shown in FIG. The obtained yellowish brown particle powder has an average long axis diameter of 0.3 μm and an axial ratio (long axis) as shown in an electron micrograph (× 30,000) shown in FIG. 7 and an enlarged photograph (× 100,000) shown in FIG. It was confirmed that the particles consisted of acicular hydrous iron oxide particles having a shaft diameter / minor axis diameter of 10 and a specific surface area of 95 m ² / g.

The adsorption performance of hydrogen sulfide of the acicular hydrous ferric oxide particles is 0.42 ppm for the test gas after aeration for 15 minutes, and the adsorption capacity is 0.90 ppm for the test gas after aeration for 120 minutes. It was

Comparative Example 2 5 l of a 1.57 mol / l FeSO ₄ aqueous solution was added to the reaction vessel, and the temperature was adjusted to 30 ° C. Then, while blowing air at a rate of 20 liters per minute, 0.2 liter of a 4 mol / l aqueous ammonia solution
(The amount of ammonia corresponds to 5.0% of the total Fe amount.)
Was neutralized with to obtain an aqueous solution containing yellowish brown seeds. At this time
The pH was about 3.

Then, while aerating air at a rate of 201 per minute, the reaction temperature was adjusted to 80 ° C and the pH of the 4 mol / l aqueous ammonia solution was adjusted.
The addition was carried out so as to maintain the range of 2.5 to 4.0, and the oxidation reaction was carried out for 5 hours.

The produced yellowish brown precipitate particles were separated, washed with water, dried and pulverized by a conventional method to obtain 629 g of yellowish brown particle powder.

As a result of electron microscopic observation, it was confirmed that the obtained yellowish brown particle powder was composed of porcelain ferric hydroxide particles.

The particle powder had an average diameter of 0.9 μm and a specific surface area of 85 m ² / g.

The hydrogen sulfide adsorption performance of the above-mentioned burdock-shaped ferric hydroxide particles, the concentration of the test gas after aeration for 15 minutes is 0.27 ppm,
The adsorption capacity was such that the test gas concentration after aeration for 120 minutes was 0.6.
It was 5 ppm.

〔The invention's effect〕

The deodorant for sulfur compounds according to the present invention is excellent in adsorption ability of sulfur compounds such as sulfur malodorous substances and sulfur oxides in the air or gas, especially since it is excellent in adsorption ability at the time of use at room temperature and dry type. Most suitable as a deodorant for compounds.

[Brief description of drawings]

FIG. 1 shows the evaluation results of the hydrogen sulfide adsorption performance of the ferric oxide hydroxide particles obtained in Experimental Example 1. FIG. 2 shows the evaluation results of the hydrogen sulfide adsorption capacity of the ferric oxide hydroxide powder obtained in Experimental Example 2. In FIGS. 1 and 2, a curve A is a ferric oxide hydroxide fine particle powder obtained in Example 1, a curve B is a ferric hydroxide fine particle powder obtained in Comparative Example 1, and a curve C is a comparative example. It is the ferric oxide hydroxide particle powder obtained in 2. FIG. 3 is an X-ray diffraction pattern of the ferric oxide-containing fine iron oxide powder obtained in Example 1, and the peak in the figure is α-FeOOH.
FIG. 4 is an electron micrograph (× 30,000) showing the particle structure of the ferric oxide hydroxide fine powder obtained in Example 1.
FIG. 5 is an enlarged photograph (× 150,000). FIG. 6 is an X-ray diffraction pattern of the ferric oxide-containing fine iron oxide powder obtained in Comparative Example 1, and the peak in the figure is α-FeOOH.
FIG. 7 is an electron micrograph (× 30,000) showing the particle structure of the ferric hydroxide-containing fine particle powder obtained in Comparative Example 1.
FIG. 8 is an enlarged photograph (× 100,000).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Nansei Horiishi 29-5 Ushidahigashi, Higashi-ku, Hiroshima City, Hiroshima Prefecture Examiner Osamu Kawabata

Claims (1)

[Claims] 1. A major axis diameter of 0.1 which has a stripe-shaped ultrafine structure.
A deodorant for sulfur compounds, which comprises a powder of ferric oxide hydroxide particles in the form of bamboo leaves having an axial ratio (major axis diameter / minor axis diameter) of 3 to 10 at 2 to 1.0 μm.