JP2005034365A - Deodorizing adsorbent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deodorizing adsorbent which adsorbs various odor-causing molecules of a nitride compound such as ammonia, surfur compounds such as mercaptan, short chain fatty acid such as acetic acid, aldehydes such as formaldehyde, and hydrocarbons such as organic solvent which a human body feels uncomfortable odor in general, and which is inexpensive and simple to handle. <P>SOLUTION: 20 to 90 pts.wt. milled active carbon obtained by milling active carbon to have maximum particle size of ≤100 μm and 10 to 80 pts.wt. milled solid acid obtained by milling solid acid consisting of at least one kind of activated clay, acid clay and synthetic silica alumina to have the maximum particle size of ≤100 μm are mixed, and a proper binder is added to the mixture to mold. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a deodorizing adsorbent that removes a substance causing bad odor by adsorption and performs deodorization.

  As houses become highly airtight and highly insulated, ventilation of indoor air becomes harder than conventional houses, and substances that cause various odors tend to be trapped indoors. In such an environment, various odors (living odors) generated in the living environment such as when continuing long-term care or when raising pets have been regarded as a problem as resident stress. It was. In addition, various solvents such as formaldehyde used in residential building materials have become known as causative substances for sick house disease, and reduction of odors and chemical substances in indoor air has been strongly demanded.

  In general, the main causative substances that the human body feels as an unpleasant odor include nitrogen compounds such as ammonia, sulfur compounds such as mercaptans, lower fatty acids such as acetic acid, aldehydes such as formaldehyde, and hydrocarbons such as organic solvents.

  Usually, indoor air ventilation is most effective in removing odors. However, since the cool air and warm air in the room are lost at every ventilation, the cooling / heating efficiency is lowered. In addition, in order to inhale outside air while always circulating and exhausting indoor air, it is necessary to install a dedicated duct, a fan, etc., and the construction of the house is expensive. Furthermore, in the case of collective housing, construction itself is often impossible.

  Therefore, for the purpose of reducing the odor from indoor air, adsorbents that have focused on charcoal adsorption have been used for some time. In particular, activated carbon is known to have a property in which pores are formed on its surface by activating wood, coconut shell, etc., and odor molecules are adsorbed in the pores. The activated carbon thus obtained is used, for example, in a cushion body for deodorization (see Patent Document 1). Also, minerals such as zeolite have been used for the purpose of absorbing human waste from pets and the like and simultaneously removing ammonia odor (see Patent Document 2).

However, in conventional adsorbents for deodorizing purposes, deodorizing components such as activated carbon and zeolite have been used alone. Furthermore, while activated carbon exhibits extremely high adsorption capacity for hydrophobic molecules, it is difficult to say that the adsorption capacity for hydrophilic molecules (polar molecules) is high. In addition, it has been pointed out that zeolites have extremely strong absorption of moisture, so that the ability to adsorb basic compounds is significantly inhibited. Thus, when each adsorbent is used alone, the molecules to be adsorbed are limited, and it has been difficult to treat a wide variety of odor molecules.
JP-A-8-173513 JP-A 63-185323

  The present invention has been made in view of the above points, and provides a deodorant adsorbent that can be handled inexpensively and easily and that treats a wide variety of odor molecules.

  That is, in the invention of claim 1, the activated carbon is pulverized activated carbon pulverized to a maximum particle size of 100 μm or less, and the solid acid containing at least one of activated clay, acidic clay, and synthetic silica alumina is the particle size of 100 μm or less. The deodorized adsorbent is characterized by mixing and molding a pulverized solid acid.

  The invention according to claim 2 relates to the deodorizing adsorbent according to claim 1, wherein 20 to 90 parts by weight of the pulverized activated carbon is mixed with 10 to 80 parts by weight of the pulverized solid acid.

  According to the deodorizing adsorbent according to the present invention, the maximum particle size of a solid acid which is one or more of pulverized activated carbon obtained by pulverizing activated carbon to a maximum particle size of 100 μm or less, activated clay, acid clay, and synthetic silica alumina. Since pulverized solid acid pulverized to 100 μm or less is mixed and molded, it is possible to adsorb a wide variety of odor-causing molecules such as nitrogen compounds, sulfur compounds, lower fatty acids, aldehydes, and hydrocarbons.

  In particular, 20 to 90 parts by weight of the pulverized activated carbon is mixed with 10 to 80 parts by weight of the pulverized solid acid, so that adsorption of a wide variety of odor-causing molecules can be performed while taking advantage of the mutual adsorption characteristics.

  In addition, unlike the conventional zeolite, an effective deodorant adsorbent was obtained particularly when used under high humidity. For this reason, it is possible to easily and inexpensively cope with an adsorption process for living odors and the like that tend to be confined to the house even during periods of high humidity.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic view showing the manufacturing process of one embodiment of the present invention.

  The deodorizing adsorbent of the present invention defined in claim 1 will be described based on the schematic diagram of FIG. First, activated carbon is pulverized to a maximum particle size of 100 μm or less to obtain pulverized activated carbon. Next, one or more of activated solid clay, acidic clay, and synthetic silica alumina are selected from the solid acids and pulverized to a maximum particle size of 100 μm or less in the same manner as the activated carbon to obtain a pulverized solid acid. Subsequently, the pulverized activated carbon and the pulverized solid acid are weighed and mixed sufficiently based on the blending ratio described later. After the mixing, an appropriate amount of binder is added, molded into a predetermined shape, and further dried to form a deodorant adsorbent.

  In general, charcoal and bamboo charcoal obtained by firing thinned wood, waste bamboo, etc. in an oxygen-free or low-oxygen atmosphere are used as plant-derived carbides for adsorption of odorous molecules. It has been. However, these plant-derived carbides contain trace metal content in the form of potassium carbonate, calcium hydroxide, etc. after carbonization. For this reason, if the charcoal, bamboo charcoal, etc. are inadvertently combined with the solid acid, the residual trace metal content acts basicly at the time of wet mixing with the solid acid or under high humidity, and the acidity of the solid acid. The degree is lowered and its performance is reduced. Therefore, when using charcoal, bamboo charcoal, etc., it is essential to wash with water in order to remove trace metal components such as potassium carbonate and calcium hydroxide.

  Taking the above points into consideration, it is preferable to use activated carbon from which trace metal components such as potassium carbonate and calcium hydroxide have already been removed as the constituent material of the deodorizing adsorbent of the present invention. In general, activated carbon is obtained by developing pores by various activations such as acid activation, alkali activation, and steam activation after firing wood materials such as thinned wood, waste wood, and plant materials such as coconut shells. Since the contained trace metal component is removed during the activation treatment, the remaining components (contained trace metal component) other than carbon are suppressed in the activated carbon. In addition, it is also possible to obtain activated carbon in which the remaining components other than carbon are further reduced by firing and activating known petroleum resins such as petroleum pitch and phenolic resin in addition to plant raw materials.

In addition, as the physical properties of the activated carbon, it is considered that the specific surface area is 500 to 1000 m ² / g, the pore volume is 0.2 to 0.6 mL / g, and the pore diameter is 0.5 to 2 nm. Desirable materials satisfying these conditions are selected from above.

As another constituent material, activated clay, acidic clay, and synthetic silica alumina are selected as defined in claim 1. The above three types of materials are known as amorphous solids or amorphous solids (amorphous solids) in which silica component (SiO ₂ ) and alumina component (Al ₂ O ₃ ) are mixed in various proportions. It is included in one of The action of the solid acid in the present invention is considered to have the effect of improving the adsorption performance of the activated carbon by the interaction with the activated carbon in addition to the adsorption of the polar odor molecule caused by the acidity of the solid acid itself.

  In general, the solid acid includes H-type zeolite in addition to the synthetic silica alumina and the like. However, since the water absorption is too strong, as is clear from the background art and the examples described later, It is unsuitable for constituting a deodorant adsorbent.

The activated clay, acid clay, the specific surface area of a solid acid which is posted in claim 1 as synthetic silica alumina, generally activated clay 100 to 200 m ² / g, the acid clay is 100 m ² / g, synthetic silica alumina 300~600m It is around ² / g. Each of the activated clay, the acid clay, and the synthetic silica alumina can be used alone or in combination with activated carbon. Furthermore, for example, activated carbon can be combined with two types of solid acids, activated clay and synthetic silica alumina.

  The activated carbon and the solid acid are each dry pulverized by a known pulverizing apparatus such as a vibration mill and a pot mill until the maximum particle size becomes 100 μm or less, thereby becoming a pulverized activated carbon and a pulverized solid acid. The activated carbon and the solid acid are pulverized to 100 μm or less, whereby there is an advantage that the particles are uniformly mixed. The lower limit of the maximum particle size is appropriately set according to the purpose of use. When wet pulverization is performed by a ball mill or the like, the pulverized activated carbon and the pulverized solid acid contain water, and there is a high possibility that an error occurs in the mixing ratio between the two, resulting in a decrease in workability.

  As defined in claim 2, the pulverized activated carbon and the pulverized solid acid pulverized to a maximum particle size of 100 μm or less have a predetermined ratio in the range of 20 to 90 parts by weight of pulverized activated carbon to 10 to 80 parts by weight of pulverized solid acid. They are blended one by one and mixed uniformly with a known ore stirrer. As will be apparent from the examples described later, when the blending ratio of the pulverized solid acid and the pulverized activated carbon is 20 parts by weight or less with respect to 80 parts by weight, the adsorptive capacity of hydrophobic molecules decreases. On the other hand, when the ratio of the pulverized solid acid to the whole is 10 parts by weight or less, the adsorption ability of the hydrophilic molecules is lowered. As a result of taking these into consideration, it is desirable that the blending ratio specified in claim 2 be adopted.

  The mixture of the pulverized activated carbon and the pulverized solid acid is subjected to press molding, extrusion molding, tableting molding, rolling granulation, and the like by using a known molding machine and granulator, and has a plate shape, a rod shape, and a honeycomb shape. Molded into various shapes such as granular. At the time of molding, a necessary amount of a water-soluble organic polymer such as carboxymethylcellulose, polyethylene glycol, polyvinyl alcohol or the like is appropriately added as a binder in order to improve the moldability of the pulverized activated carbon and the pulverized solid acid.

  As described above, the molded product molded into various shapes is dried at 80 to 100 ° C. for 5 to 10 hours in a known dryer such as an electric type or a gas type. It is desirable to perform drying in order to remove moisture that has entered the pulverized activated carbon and the pores of the pulverized solid acid at the time of molding and to improve the odor removing ability.

  The deodorant adsorbent thus obtained can be, for example, sprayed under the floor of a house, inside a wall, behind a ceiling, etc., and can also be enclosed inside a tatami mat, wallpaper, partition, or the like. Further, it can be used for interior materials such as automobiles, ships, aircrafts, etc., and can be used to remove odors in the interior of the vehicle. In addition, the use of mats for pets, breeding facilities for livestock, etc. is also considered.

<Prototype of deodorant adsorbent>
In prototyping the deodorant adsorbent of the present invention, the activated carbon used was a granular activated carbon (activated carbon derived from coconut shell) made by Nimura Chemical Co., Ltd .: Dazai activated carbon. The activated clay was made by Mizusawa Chemical Co., Ltd .: Galeon Earth, the acidic clay was made by Mizusawa Chemical Co., Ltd .: Mizuka Ace, and the synthetic silica alumina was made by Catalyst Kasei Kogyo Co., Ltd .: silica alumina. In the above-mentioned raw materials, the activated carbon was classified in advance by a 75 μm JIS standard 200 mesh sieve, and only a particle size of 75 μm or less was used. The activated clay, acid clay, and synthetic silica alumina were pulverized by a pot mill and classified by a 75 μm standard sieve in the same manner as activated carbon, and only a particle size of 75 μm or less was used.

  Each raw material (crushed activated carbon and pulverized solid acid) obtained by pulverization and classification is individually mixed as shown in the following Tables 1, 2 and 3, or uniformly mixed by a stirrer after weighing based on a predetermined weight ratio. did. After mixing these, about 5% carboxymethylcellulose aqueous solution (2% by weight) was added as a binder to the total weight, and tumbling granulation (molding) into granules having a particle diameter of 5 mm using a granulator. The granulated product thus obtained was dried at 100 ° C. for 5 hours using a dryer, and a deodorant adsorbent of the present invention was prototyped. In addition, in order to prevent moisture absorption after drying, the deodorizing adsorbent was stored in a desiccator.

<Evaluation of deodorant adsorption effect>
To evaluate the deodorant adsorption effect, put the prototype deodorant adsorbent into a sealed container filled with odor-causing molecules and compare the rate of change from the initial weight of the deodorant adsorbent after a certain period of time. To do.

  As a sealed container, a glass desiccator having an internal volume of 5 L was used. As molecules causing odor, ammonia, formaldehyde (partly acetaldehyde), methyl sulfide, ethanol, and toluene were selected as indicator substances. About these odor-causing molecules, ammonia water (reagent special grade), formalin (reagent special grade), acetaldehyde (reagent special grade), acetic acid (reagent special grade), methyl sulfide (reagent special grade), ethanol (reagent special grade), toluene (reagent special grade) Each of these was weighed one by one and placed in a desiccator. Each of the prototype deodorant adsorbents was added to the desiccator to adsorb odor-causing molecules filling the desiccator.

  The desiccator in which the odor-causing molecules weighed in predetermined amounts and each prototype deodorant adsorbent were sealed was allowed to stand at 20 ° C. for 48 hours. Thereafter, the weight of each deodorant adsorbent was quickly weighed, and the change rate (%) from the initial weight, that is, [change rate (%) = (weight after adsorption−initial weight) / initial weight × 100] was calculated. .

<Example 1: Comparison of carbon-based materials>
In Example 1, the above-mentioned activated carbon: the adsorption capacity of the odor-causing molecule by sample 1-1 and bamboo charcoal: sample 1-2, Bincho charcoal: sample 1-3, charcoal: the same adsorption capacity by sample 1-4 did. Bamboo charcoal, Bincho charcoal, and charcoal were pulverized by a pot mill and classified by a 75 μm standard sieve in the same manner as activated carbon, and only a particle size of 75 μm or less was used, and these were granulated in the same manner.

  After adding the above 6 kinds of odor-causing molecules (ammonia water 50 mL, formalin 50 mL, acetic acid 30 mL, methyl sulfide 10 mL, ethanol 30 mL, toluene 30 mL), activated carbon (sample 1-1), bamboo charcoal (sample 1-2), Bincho Each 1 g of charcoal (sample 1-3) and charcoal (sample 1-4) was accurately collected, sealed in the desiccator, and allowed to stand at 20 ° C. for 48 hours. Table 1 shows the result of the rate of change (%) from the initial weight. In evaluating the carbon-based material, ammonia water was diluted to 10% and used.

As shown in Table 1, it can be seen that the adsorption ability of the activated carbon (sample 1-1) is generally good. This is easily inferred from the fact that the specific surface area of activated carbon is about 1000 m ² / g and the specific surface area of charcoal is 300 to 400 m ² / g. In addition, as a feature of the carbon-based material, among 6 types of acetic acid and toluene, a high boiling point and high adsorbing ability is exhibited for a compound having a large molecular weight. On the other hand, among 6 types of ammonia and formaldehyde (formalin), the adsorption ability for a compound having a low boiling point and a small molecular weight is low. That is, in the carbon-based material, it is considered that a graphite-like structure develops on the surface and becomes more hydrophobic as it is activated.

<Example 2: Comparison in solid acid materials>
In Example 2, the above-described synthetic silica alumina was selected as the solid acid, 50 parts by weight of activated carbon was blended with 50 parts by weight of synthetic silica alumina, and the deodorant adsorbent obtained by the same procedure as above: sample For comparison with 2-1 and 50 parts by weight of magnesia (manufactured by Wako Pure Chemical Industries, Ltd .: reagent grade), 50 parts by weight of activated carbon was blended, and similarly obtained deodorant adsorbent: Sample 2-2 Prototyped. Deodorized adsorbents obtained from the activated carbon alone: Sample 1-1 was added to this and compared. In this comparison, ammonia, acetic acid, acetaldehyde, and methyl sulfide were used as odor-causing molecules, and 50 mL of aqueous ammonia, 30 mL of acetic acid, 30 mL of acetaldehyde, and 10 mL of methyl sulfide were added based on the same procedure as above, and 20 ° C., 48 hours. The rate of change (%) from the initial weight of each sample after standing (all samples were 1 g) was calculated. The results are in Table 2. In the comparison of the solid acid materials, the content of ammonia water was 30%.

  As shown in Table 2, the deodorant adsorbent (sample 2-2) containing magnesia exhibits high adsorption ability for acetic acid and acetaldehyde. However, the adsorption capacity for ammonia was significantly reduced. This is because minerals found in magnesia and the like are known as solid bases and are considered to act basicly. Considering the whole, it can be said that the deodorant adsorbent (sample 2-1) containing synthetic silica alumina is good in adsorption of four kinds of odor-causing molecules.

<Example 3: Comparison of compounding ratio in carbon-based material / solid acid-based material>
A carbon-based material and a solid acid-based material were used alone or by changing the blending ratio as appropriate, and a deodorant adsorbent was made as a trial and the adsorption capacity was compared. Also, the difference in particle size during pulverization was evaluated.

  In Example 3, deodorized adsorbent obtained from the activated carbon alone: Sample 1-1, deodorized adsorbent obtained from the activated clay alone: Sample 3-1, 50 parts by weight of activated carbon with respect to 50 parts by weight of activated clay. Deodorant adsorbent containing: sample 3-2, deodorized adsorbent obtained from the synthetic silica alumina alone: sample 3-3, deodorant containing 50 parts by weight of activated carbon to 50 parts by weight of synthetic silica alumina Adsorbent: Sample 2-1, deodorized adsorbent containing 90 parts by weight of activated carbon with respect to 10 parts by weight of synthetic silica alumina: 80 parts by weight of activated carbon with respect to sample 3-4, 20 parts by weight of synthetic silica alumina Deodorant adsorbent: Sample 3-5, HY zeolite (manufactured by Catalyst Kasei Kogyo Co., Ltd .: HY zeolite) alone Deodorized adsorbent: Sample 3-6, 50 parts by weight of the HY zeolite In contrast, 50 parts by weight of activated carbon is blended. Deodorant adsorbent: a prototype of the sample 3-7. For all the deodorizing adsorbents listed, those having a particle size adjusted to 75 μm or less during pulverization were used. In addition, a deodorant adsorbent containing 50 parts by weight of synthetic silica alumina whose particle diameter at the time of pulverization was adjusted to 0.1 to 0.5 mm and 50 parts by weight of activated carbon (manufactured by Nimura Chemical Co., Ltd .: Taiho activated carbon): Sample 3-8 was also prototyped.

  In this comparison, ammonia and formaldehyde were used as odor-causing molecules, and 50 mL of ammonia water and 30 mL of formalin were added based on the same procedure as above, and the initial weight of each sample after standing at 20 ° C. for 48 hours (any sample) Also, the change rate (%) from 1 g) was calculated. The results are in Table 3. In addition, 30% of ammonia water was used.

  As shown in Table 3, the deodorizing adsorbent (sample 3-6) using the HY zeolite showed no ammonia adsorption ability. In general, zeolite has a high hygroscopicity. In particular, when ammonia water is sealed in a sealed container as in this embodiment, the humidity in the container rises, and it is considered that this moisture is absorbed by zeolite and inhibits ammonia adsorption. Of course, there was no improvement even when combined with activated carbon as in Sample 3-7. In this way, it can be said that it is unsuitable to use zeolite as a deodorant adsorbent used in a house or the like.

  The activated clay (sample 3-1) and synthetic silica alumina (sample 3-3) can confirm the adsorption ability even when used alone, but the adsorption ability is further increased by combining with activated carbon. When the blending ratio is changed (Sample 2-1, Sample 3-4, Sample 3-5), since the balance of adsorption for each odor-causing molecule is deteriorated, it is not preferable to increase or decrease one of them extremely. It is considered that the deodorant adsorbent (Sample 3-8) whose particle size at the time of pulverization is adjusted is one in which the surface area of the whole granulated product is reduced and the adsorbing ability is lowered.

It is the schematic showing the manufacturing process of one Example of this invention.

Claims (2)

Pulverized activated carbon obtained by pulverizing activated carbon to a maximum particle size of 100 μm or less;
A pulverized solid acid obtained by pulverizing a solid acid having at least one of activated clay, acid clay, and synthetic silica alumina to a maximum particle size of 100 μm or less;
A deodorant adsorbent characterized by mixing and molding.   The deodorizing adsorbent according to claim 1, wherein 20 to 90 parts by weight of the pulverized activated carbon is mixed with 10 to 80 parts by weight of the pulverized solid acid.

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