JPH0438452B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an air purifying agent, and is particularly effective in removing tobacco odor from indoor air in offices, homes, and the like. [Prior art] An adsorbent in which activated carbon is impregnated with aniline was developed in the 1980s.
No. 54095 discloses that activated carbon impregnated with aniline in an amount of 3 to 30% by weight (based on activated carbon) is effective in adsorbing lower aliphatic aldehydes such as formaldehyde and acetaldehyde in the gas phase. Regarding the use of iron salts for deodorization, JP-A-57-99318 and JP-A-57-113826 describe a method of adding a polymeric substance to a colloidal solution containing iron salts to stabilize the solution and maintain its effect. Furthermore, JP-A-58-156539 describes a method of stabilizing the solution and improving the deodorizing power by adding L-ascorbic acid to an aqueous solution of an iron compound. Furthermore, there is Japanese Patent Application Laid-Open No. 58-26810, which uses activated carbon impregnated with an organic acid for use as a deodorizing agent, and it is stated that adsorption of ammonia is significantly increased by impregnating activated carbon with citric acid. ing. [Problems to be Solved by the Invention] Activated carbon is a unique material that has extremely excellent adsorption properties as a non-polar adsorbent, and exhibits high adsorption properties for almost all gaseous substances. The indoor air in living spaces such as offices and homes usually has a strong odor of cigarettes.
Compositionally, it contains acetaldehyde, ammonia, lower amines, hydrocarbons, hydrogen sulfide, etc.
Note that the cigarette odor here refers to the odor of gas generated when smoking. In particular, activated carbon has a high proportion of ammonia, which is a weak point in adsorption, and also has a relatively large amount of lower aliphatic aldehydes, so it is difficult to remove the odor using ordinary activated carbon alone. There was a demand for an adsorbent that would remove the [Means for Solving the Problems] The present inventors have studied the compositions of various impregnated activated carbons and the deodorizing properties when they are combined.
The results showed that lower aliphatic aldehydes can be completely removed by adding activated carbon impregnated with aniline, and that the synergistic effect on ammonia adsorption is further promoted by adding activated carbon impregnated with malic acid, iron salt, and aniline. The present invention was completed on the basis of this discovery. That is, it is an air purifying agent that is a mixture of activated carbon impregnated with aniline, malic acid, iron salt, and activated carbon impregnated with aniline. The present invention will be explained in detail below. The activated carbon used here is usually several grams per gram.
Carbon materials having a large surface area of 100 m ² or more and exhibiting high adsorption properties can be used in a wide range of applications. The raw material for activated carbon is usually carbonized material such as coconut shell or wood, or coal, but any of them may be used.
Further, the activation method may be one obtained by using steam or carbon dioxide at high temperature, or by treatment with zinc chloride, malic acid, concentrated sulfuric acid, or the like. Although the effect can be recognized in any shape such as crushed coal, granulated coal, or granulated coal, a sheet-like adsorption layer impregnated with granulated carbon or activated carbon is convenient in terms of handling such as pressure loss and replacement. Granulated coal is made into carbon material according to the conventional method.
It is adjusted by adding 30 to 60 parts of petroleum pitch or coal tar as a binder to 100 parts, mixing and molding, and then activating it. Activated carbon impregnated with aniline exhibits extremely high adsorption properties for lower aliphatic aldehydes such as formaldehyde and acetaldehyde, and the amount of impregnation is not particularly limited. Activated carbon also exhibits high adsorption properties for aniline, and since the aniline is adsorbed and retained within its pores, the vapor pressure is significantly suppressed and generally almost no odor is felt. However, if the amount of impregnation is too high, there is a risk that some of the aniline will be desorbed, and if the amount is too small, the effect of impregnating aniline will be poor, so a range of 3 to 30% by weight is more preferable. To impregnate activated carbon with aniline, soak the activated carbon in an aqueous aniline solution for 2 to 3 hours at room temperature, then separate.
In addition to the drying method, it can also be adjusted by passing a gas containing aniline through an activated carbon packed bed and adsorbing it in the gas phase. Activated carbon impregnated with malic acid and iron salts exhibits high adsorption properties for ammonia and amines.
The amount of impregnation is not particularly limited. However, if the amount of malic acid impregnated is small, the effect is poor, and if the amount of malic acid impregnated increases, the adsorption ability of activated carbon for other substances will be significantly inhibited, so the amount of malic acid impregnated should be 5 to 30% by weight. preferable. Iron salts are widely recognized to have an ammonia adsorption effect, and the types are not limited, but iron salts include ferrous sulfate, ferric sulfate, ferrous chloride, ferric chloride, ferrous phosphate, and ferrous phosphate when handling them. 2 iron etc. are more preferable. The synergistic effect of impregnating iron salts and malic acid is quite remarkable, but when the amount of impregnation is small, the effect is poor, and when the amount of impregnation is large, the adsorption capacity of activated carbon for other substances is reduced, although not as much as with malic acid. Therefore, the amount of iron salt impregnated is preferably 3 to 25% by weight. To impregnate activated carbon with malic acid and iron salts, immerse the activated carbon in a mixed solution of malic acid and iron salts so that they are sufficiently absorbed into the pores, and then filter and dry, or sprinkle these solutions on the activated carbon. The material may be sufficiently impregnated and then dried. At this time, it is important to uniformly impregnate the malic acid and iron salt into the pores of the activated carbon, so it is necessary to dry at a slow speed. If the drying rate is too fast, the acid and iron salt that were once adsorbed inside the activated carbon may be desorbed and deposited on the surface of the activated carbon, resulting in a decrease in its performance. In addition, this impregnated activated carbon must be used in a state containing a small amount of water, since its adsorption ability for ammonia and amines is significantly reduced in an absolutely dry state. The above activated carbon impregnated with malic acid and iron salt is further impregnated with aniline. This activated carbon exhibits high adsorption properties for ammonia and amines, as well as good adsorption properties for lower aliphatic aldehydes, and the amount of impregnation is not particularly limited. However, if the amount of aniline impregnated is too large, it will inhibit the adsorption ability of activated carbon for other substances, have a negative effect on malic acid and iron salts, and reduce the adsorption ability of ammonia and amines. Since the effect is poor, the amount of aniline applied should be 2~
10% by weight is preferred. The method for adding aniline is carried out in the same manner as described above. The air purifying agent of the present invention is prepared by mixing the above-described activated carbon impregnated with aniline and the activated carbon impregnated with malic acid, iron salt, and aniline. The deodorizing agent prepared in this way is effective in deodorizing living spaces such as offices and homes that mainly contain cigarette odors at a wide range of impregnating ratios and mixing ratios, and the mixing ratio is not particularly limited. Therefore, when each component has a preferable composition as described above, Examples 3, 4 and 5
In order to suppress the decrease in adsorption for substances other than specific substances such as aldehydes and ammonia, as shown in Figure 2, 40 to 80% by weight of activated carbon impregnated with aniline, and 20 to 60% by weight of activated carbon impregnated with malic acid, iron salts, and aniline. It is preferable to select and mix from within this range. [Action] Activated carbon is originally a non-polar adsorbent and exhibits high adsorption properties for almost all gaseous substances, but it has relatively low adsorption power for lower aliphatic aldehydes, which are relatively abundant in cigarette odors. is weak. In addition, the adsorption amount of ammonia, which has a high proportion in tobacco odor, is very small. However, the present invention provides malic acid,
By mixing iron salts and aniline-impregnated activated carbon, the adsorption performance for lower aliphatic aldehydes is good, and in addition to increasing ammonia adsorption ability, aniline-impregnated activated carbon is added to remove lower aliphatic aldehydes extremely efficiently. This is what I did. The action of malic acid-impregnated activated carbon to adsorb ammonia is thought to be due to neutralization, and in the case of iron salts, it is thought to be due to complex formation, although the details are not clear.
When activated carbon is impregnated with an equal amount of only malic acid or only iron salt, malic acid exhibits higher ammonia adsorption ability, but the adsorption ability of activated carbon to other substances is significantly reduced. When malic acid and iron salt are impregnated in the range described in claim 3, the ammonia adsorption property is the same as when malic acid or iron salt is impregnated alone. It reaches several times the calculated value. Therefore, since the required ammonia adsorption ability can be maintained even with a relatively small amount of mixed impregnation, there is an advantage that the adsorption ability of the base activated carbon to other substances is not inhibited. Furthermore, the adsorption of ammonia by this mixed impregnated coal is particularly efficient at low concentrations, and even if the gas concentration fluctuates, it is difficult to re-release the adsorbed gas. This is considered to be because ammonia adsorption is based on a chemical reaction mechanism. In addition to ammonia, the adsorption of amines is also high, and the mechanism is thought to be similar. Furthermore, it is thought that malic acid is strongly adsorbed in the pores of the activated carbon, and almost no odor is felt. Next, as an adsorbent for aldehydes, there are known adsorbents such as activated carbon impregnated with sulfite or acid sulfite, but compared to these, the aniline-impregnated carbon used in the present invention is lower in grade. It has high aliphatic aldehyde adsorption properties, especially in the low concentration range (aldehyde concentration 100 ppm or less). When aniline is impregnated, safety and health considerations are required, but no odor is felt at all when the amount of aniline is impregnated as described in claim 2, which is preferred from the standpoint of aldehyde adsorption. This is thought to be because aniline molecules are strongly adsorbed in the pores of activated carbon. By the way, the adhesion amount is 5, 10, 15,
A sensory test was conducted to determine the odor when 20, 25, and 30% by weight samples were prepared and left in a closed container at room temperature (25°C).
As a result of analysis using a high-sensitivity gas chromatograph equipped with an FID (flame ionization detector), no odor was detected in the sensory test, and no aniline was detected using the gas chromatograph. Activated carbon impregnated with malic acid and iron salt is further impregnated with aniline, which is mixed with formaldehyde,
Lower aliphatic aldehydes such as acetaldehyde are physically adsorbed to activated carbon to some extent, but the retention force is small, so when clean air flows through activated carbon that has been adsorbed above the retention limit, lower aliphatic aldehydes are re-released. In addition, because the olfactory threshold of aldehydes is at a low concentration, there is a unique odor of aldehydes.
Using activated carbon impregnated with only malic acid and iron salts may even have an adverse effect. Therefore, activated carbon, which chemically adsorbs ammonia and amines, is also treated with aniline to chemically adsorb lower aliphatic aldehydes. [Examples] The present invention will be specifically described below with reference to Examples, but these Examples are not intended to limit the present invention in any way. Example 1 A sample weighing 2 g (anhydrous equivalent) was placed in a glass bottle with a capacity of 3.97 liters, and after degassing with a vacuum pump, a predetermined amount of aqueous ammonia was added and vaporized. Next, air was introduced to return the pressure to normal pressure, and the mixture was left in a constant temperature bath at 25°C, and the ammonia concentration was measured using a gas detection tube. The relationship between the amount of ammonia adsorbed and the gas concentration when equilibrium was reached was investigated, and the isothermal adsorption curve was measured. Activated carbon (unimpregnated carbon) and malic acid and sulfuric acid No. 1
Iron-impregnated carbon (20% by weight) and mixed impregnated carbon (acid)
14% by weight, 6% by weight of iron sulfate), and a three-component mixed impregnated carbon of malic acid, ferrous sulfate, and aniline (acid 14% by weight)
weight%, iron sulfate 6% by weight, aniline 3% by weight),
Furthermore, aniline-impregnated carbon (8% by weight), malic acid,
Carbon impregnated with a three-component mixture of ferrous sulfate and aniline (acid 14
The results are shown in FIG. 1 for a 6:4 mixture of 6% iron sulfate and 3% aniline by weight. Example 2 In the same manner as in Example 1, a sample was placed in a container and then degassed, and a predetermined amount of acetaldehyde aqueous solution was added and vaporized. Next, air was introduced and left to stand, and the acetaldehyde concentration was measured with a gas detection tube, and the isothermal adsorption line when equilibrium was reached was measured. Activated carbon and its aniline-impregnated carbon (8% by weight), aniline-impregnated carbon (8% by weight), malic acid, ferrous sulfate, aniline mixed impregnated carbon (acid 14% by weight, iron sulfate 6% by weight, aniline 3% by weight) The measurement results for a 6:4 mixture of ) are shown in FIG. Example 3 In the same manner as in Example 1, a sample was placed in a container and then degassed, and a predetermined amount of benzene was added and vaporized. Next, air was introduced and left to stand, and the benzene concentration was measured using a gas chromatograph, and the isothermal adsorption line when equilibrium was reached was measured. Activated carbon and its aniline-impregnated carbon (8
(% by weight), malic acid, ferrous sulfate, and aniline mixed impregnated carbon (14% by weight of acid, 6% by weight of iron sulfate, 3% by weight of aniline) at a mixing ratio of 8:2, 6:4, 4:6.
The results are shown in Figure 3. Example 4 In the same manner as in Example 1, a sample was placed in a container and then degassed, a predetermined amount of hydrogen sulfide gas was added, air was then introduced, and the concentration of hydrogen sulfide was measured using a detection tube. The mixing ratio of activated carbon and its aniline-impregnated carbon (8% by weight), malic acid, ferrous sulfate, and aniline mixed impregnated carbon (14% by weight of acid, 6% by weight of iron sulfate, 3% by weight of aniline) was 6:4,4. :6 is shown in FIG. 4. Example 5 A lit cigarette (Seven Star) is placed in an aluminum ^1m3 box with an air cleaner placed inside, and the inside of the box is stirred with a fan to burn the cigarette and eliminate the smoke and odor inside. Distribute evenly. The initial value was measured when all the cigarettes were burned, and then the air cleaner was operated to examine the relationship between the operating time and the amount of residual odor, and the adsorption speed was measured. Measurement was made using a gas detection tube for ammonia, with a boiling point of -7
Odor components such as aliphatic hydrocarbons, aromatic hydrocarbons, ketones, carbonates, nitrogen compounds such as nicotine and pyridine, and acetaldehyde at temperatures above ℃ are detected using a high-sensitivity gas chromatograph with FID, and hydrogen sulfide is detected.
Analysis was performed using a high-sensitivity gas chromatograph equipped with an FPD (flame photometric detector). The total amount of air purifying agent used in the air cleaner was 250
g, and the air volume was 2 m ³ /min. Activated carbon and its aniline-impregnated carbon (8% by weight),
Malic acid, ferrous sulfate, aniline mixed impregnated carbon (acid
35% by weight, 6% by weight of iron sulfate, 3% by weight of aniline)
The results are shown in Figures 5 to 8 when the mixing ratios were 8:2, 6:4, and 4:6. Example 6 10 lighted cigarettes (Seven Stars) were placed in an aluminum ^1m3 box with an air cleaner containing an air purifier placed inside, and the air cleaner was operated while the cigarettes naturally burned. Adsorbed smoke and odors. When the concentration of smoke and odor became almost constant, 10 more cigarettes were added and burned, and this process was repeated to adsorb the smoke and odor of a total of 60 cigarettes. After leaving this air purifier for one day, set it in an air cleaner and run it indoors with clean air, sample the air coming out of the air cleaner outlet, and check the acetaldehyde.
Analysis was performed using a high-sensitivity gas chromatograph with FID. This value is called the re-emission amount. The total amount of air purifying agent used in the air cleaner was 250
g, and the air volume was 2 m ³ /min. Here, aniline-impregnated charcoal (8
The results of measuring the amount of acetaldehyde released by changing the ratio of malic acid, ferrous sulfate, and aniline mixed impregnated carbon (14% by weight, 6% by weight of iron sulfate, 3% by weight of aniline) and malic acid, ferrous sulfate, and aniline impregnated carbon. Figure 9 shows a comparison of the results of measuring the amount of acetaldehyde released by changing the ratio of charcoal (8% by weight), apple, and mixed charcoal impregnated with ferrous sulfate (14% by weight of acid, 6% by weight of iron sulfate). . At the same time, a sensory evaluation was performed by smelling the air cleaner outlet, and the results are shown in Table 1.

[Table] As shown in Figure 9 and Table 1, when using an air purifying agent containing a mixture of malic acid, ferrous sulfate, and aniline mixed impregnated charcoal, the amount of acetaldehyde released remains unchanged even if the blending ratio is changed. It changes only slightly and does not emit a distinctive sweet odor. The preferred mixing ratio of the two types of activated carbon is based on the results shown in FIGS. 3 to 9 and Table 1. [Effect] As described above, the air purifying agent of the present invention can be used in offices,
It is particularly effective in removing odors in normal living environments such as homes. Furthermore, since it has a strong adsorption power for lower aliphatic aldehydes, it is also suitable for removing odors from kerosene stoves immediately after extinguishing them. Therefore, it is suitable for air cleaner filters, etc.

[Brief explanation of drawings]

Figure 1 shows the isothermal adsorption line of ammonia gas at 25°C and 60% relative humidity. 1... Activated carbon, 2... Malic acid (20% by weight) impregnated to activated carbon, 3... Ferrous sulfate (20% by weight) impregnated to activated carbon, 4... Malic acid (14% by weight) to activated carbon,
Ferrous sulfate (6% by weight) impregnated, 5... Malic acid (14% by weight), ferrous sulfate (6% by weight), aniline (3% by weight) impregnated on activated carbon, 6... Malic acid, ferrous sulfate Activated carbon impregnated with a three-component mixture of iron and aniline (acid 14
weight%, iron sulfate 6% by weight, aniline 3% by weight),
4:6 mixture of aniline-impregnated activated carbon (8% by weight). Figure 2 shows the isothermal adsorption line of acetaldehyde at 25°C and 60% relative humidity. 1...Activated carbon, 2...Activated carbon impregnated with aniline (8% by weight), 3...Malic acid, ferrous sulfate, aniline impregnated activated carbon (14% by weight of acid, 6% by weight of iron sulfate,
A 4:6 mixture of aniline (3% by weight) and aniline-impregnated activated carbon (8% by weight). Figure 3 shows the isothermal adsorption line for benzene at 25°C and 60% relative humidity. 1...Activated carbon, 2...Malic acid, ferrous sulfate,
Aniline mixed impregnated activated carbon (acid 14% by weight, iron sulfate 6
3% by weight) and aniline-impregnated activated carbon (8% by weight) in a ratio of 4:6. 3...2
The mixture ratio is 2:8, 4...2
The mixture ratio of activated carbon was 6:4. Figure 4 shows the isothermal adsorption line of hydrogen sulfide at 25°C and 60% relative humidity. 1...Activated carbon, 2...Malic acid, ferrous sulfate,
Aniline mixed impregnated activated carbon (acid 14% by weight, iron sulfate 6
3% by weight, aniline (3% by weight) and aniline-impregnated activated carbon (8% by weight) in a ratio of 4:6, 3...2
The mixing ratio was 6:4. Figure 5 shows the adsorption speed of ammonia in tobacco odor at 25°C and 60% relative humidity. Figure 6 shows the adsorption speed of acetaldehyde in tobacco odor at 25°C and 60% relative humidity. Figure 7 is
Aliphatic hydrocarbons and aromatic hydrocarbons with a boiling point of -7°C or higher in tobacco odor at 25°C and 60% relative humidity;
Indicates the adsorption speed of odor components such as ketones, carboxylic acids, and nitrogen compounds such as nicotine and pyridine.
Figure 8 shows the adsorption speed of hydrogen sulfide in tobacco odor at 25°C and 60% relative humidity. 11...Activated carbon, 12...Malic acid, sulfuric acid No. 1
A 4:6 mixture of iron, aniline mixed impregnated activated carbon (acid 14% by weight, iron sulfate 6% by weight, aniline 3% by weight), aniline impregnated activated carbon (8% by weight), 13...
12 with a mixing ratio of 2:8, 14...
...12 with a mixing ratio of 6:4. Figure 9 shows tobacco 60 at 25℃ and 60% relative humidity.
Regarding the amount of acetaldehyde re-released by air purifiers that have previously adsorbed the main odor, the relationship between the ratio of aniline-impregnated carbon to malic acid, ferrous sulfate, and aniline mixed impregnated carbon21, and the relationship between aniline-impregnated carbon and malic acid, and the ratio of aniline-impregnated carbon to malic acid, The relationship with the ratio of ferrous sulfate mixed impregnated coal22 is shown.

Claims (1)

[Claims] 1. An air purifying agent made by mixing activated carbon impregnated with aniline, malic acid, iron salt, and activated carbon impregnated with aniline. 2 Activated carbon impregnated with aniline has an impregnated amount of 3 to 30
The air purifying agent according to claim 1, which is % by weight (based on activated carbon). 3 The impregnated amount of activated carbon impregnated with malic acid, iron salt and aniline is 5 to 30% by weight of malic acid (based on activated carbon),
Iron salt 3-25% by weight (based on activated carbon), aniline 2-10
The air purifying agent according to claim 1, which is % by weight (based on activated carbon). 4 Activated carbon impregnated with aniline 40-80% by weight, activated carbon impregnated with malic acid, iron salt and aniline 20-20%
Claim 1 consisting of a mixture of 60% by weight
Air purifying agent as described in section.