JPS6115732B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an air purifying agent, and an object of the present invention is to provide an air purifying agent that has a deodorizing effect on malodorous gases such as ammonia and organic amines, and also has the effect of decomposing and removing harmful gases such as NOx. be. Bad odors not only make the living environment unpleasant, but also often impair human health. Conventionally, ammonia,
Typical bad odors such as hydrogen sulfate, mercaptans, and amines are known, and many methods have been proposed to remove these bad odors. For example, combustion methods that treat heat-generating odors at high temperatures, catalytic oxidation catalyst methods that heat-treat heat using platinum-based catalysts, adsorption methods that treat heat-treated odors with adsorbent materials such as activated carbon and silica gel, ozone oxidation methods, and chemical cleaning methods, etc. Deodorization methods adapted to different environmental conditions are adopted. Conventionally, chemical cleaning methods generally involve reacting liquid with gas, but this method is not suitable for deodorizing dilute gases because of high running costs and equipment costs. In addition, handling such as chemical solution exchange is inconvenient, and there are also problems in waste liquid disposal. Activated carbon, which is generally widely used as an adsorption deodorizing agent, is said to have a small deodorizing effect on low molecular weight gases such as ammonium. Zeolite is similarly effective in deodorizing ammonia gas, but its adsorption capacity is small when used alone, and it also has the property of desorbing even if adsorbed due to saturation of the adsorbed gas or changes in the environment. In particular, conventional deodorizing agents such as activated carbon cannot remove complex odors such as ammonia, hydrogen sulfide, and mercaptan all at once, necessitating multi-stage deodorizing operations. There are almost no products developed that can remove not only harmful gases such as NOx and SOx at the same time. Currently, solid sulfonated carbon or iron sulfate-based deodorizers are typical commercially available deodorizers for removing basic gases such as ammonia and amines, and these have an ammonia absorption capacity of about 70 to 100 mg/g. However, some deodorants themselves absorb moisture and cause discoloration or deterioration, causing the molded granules to disintegrate. If the deodorizer absorbs moisture or collapses inside the deodorizer filling container, the pressure loss will be large and it will be difficult to handle.
Deodorizing efficiency is significantly reduced. Furthermore, it is difficult to restore the deodorizing ability of some deodorizers, and depending on the ingredients contained in the deodorizer itself, there may be problems with disposal after use. On the other hand, when solidifying something that supports a deodorizing component, it is necessary to select a binder by comprehensively considering the deodorizing ability, strength, moldability, etc. It's difficult. In view of the above-mentioned problems, the present inventors have been researching the deodorization of basic malodorous gases such as ammonia and amines, and have focused on the reaction of phosphoric acid or acidic phosphates with the gases. A deodorizing agent was developed in which one or more of phosphoric acid and phosphate salts were added to a carrier to solidify it (Japanese Patent Application No. 69940/1982). On the other hand, a large number of proposals have been made for removing NOx and SOx gases, which are particularly problematic among air pollutants, but there are cases where it is economically or functionally inappropriate to remove pollutant gases at environmental concentrations. There are many. Several methods have been known to remove environmentally concentrated air pollutants, such as NOx and SOx. capacity is insufficient. In view of the above facts, the present inventors have previously succeeded in developing an improved air purifying agent containing potassium permanganate, bentonite, and zeolite as active ingredients (Japanese Patent Application No. 61046/1983). However, in general, the inventors recognized that the actual contaminated air is when malodorous gases and harmful gases such as NOx coexist, and after conducting intensive research to further improve the The present invention was completed based on the discovery that acid-supported materials have excellent air purification ability. That is, the present invention relates to an air purifying agent characterized in that it is formed by supporting and molding potassium permanganate and phosphoric acid or/and acidic phosphate on an inorganic powder carrier composed of two or more types of components. In the present invention, the inorganic carrier that can be used is substantially inert to potassium permanganate, and is an inorganic base material that is impregnated with or immobilized with phosphoric acid or the like to support it. Similar to potassium permanganate, this base material may be inert to phosphoric acid or the like, or it may be one that reacts with phosphoric acid to form an acidic phosphate. Such carriers include, for example, natural or synthetic zeolites, activated clay, diatomaceous kaolin, bentonite,
ball clay, natural or synthetic ocher, alumina,
Examples include silicic acid. Among these, those having gas adsorption ability by themselves are more suitable and can be expected to have a synergistic effect with phosphoric acid, etc., and mordenite-based zeolite, bentonite, and natural or synthetic loess are particularly preferred in the present invention. Moreover, this may be a mixture of two or more types, and due to its nature, it is not particularly limited to the above. Further, although these carriers are often powders, they may be partially modified physically into short fibers or chemically modified such as acid treatment. The inorganic carrier in the present invention must be composed of two or more inorganic base materials as described above. The reason for this is that when using only one type of base material to support and mold the drug described later, not only do many of them have poor moldability, but even if they are molded,
This is because the molding strength is low and it cannot withstand use. Therefore, in order to obtain a carrier having desired molding strength and pore volume, two or more types of base materials and their combinations can be appropriately selected and prepared. As described above, the air purifying agent according to the present invention has potassium permanganate, phosphoric acid, etc. supported on an inorganic carrier. Since the purifying ability is extremely good, if an effective molded product can be prepared, it can be cited as one of the excellent air purifying agents. However, in many cases, problems tend to occur in moldability, so it is common to use acidic phosphate alone or in combination with this salt. Such acidic phosphates preferably have excellent absorption capacity for ammonia, etc., and also have caking properties, such as Na, K, Zn, Mg, Al,
Examples include acidic metal phosphates such as Pb, Fe, and Mn, silicon phosphate, and acidic ammonium phosphate, and these may be used alone or in combination of two or more. As mentioned above, these acidic phosphates have excellent deodorizing ability like phosphoric acid, and also act as binders, so they are easy to support on carriers.
Acidic phosphates of Al, Fe or Zn are preferred. In this case, the salt to be used is not only the acidic phosphate mentioned above, but also a neutral phosphate as long as it exists as an acidic phosphate in the carrier, so when used in combination with phosphoric acid, The initial raw material may be a neutral phosphate. In the present invention, phosphoric acid often refers to general orthophosphoric acid, but may also include metaphosphoric acid, condensed phosphoric acid, phosphoric anhydride, and the like. The mixing ratio of potassium permanganate, phosphoric acid, etc. is not particularly limited, but in most cases, the weight ratio of P ₂ O ₅ /KMnO ₄ is preferably in the range of 0.2 to 2. The reason for this is that if it is less than about 0.2, the removal rate for basic gas tends to decrease, while if it is more than about 2, there is a problem with moldability. Similarly, regarding the amount of the active ingredient supported on the inorganic carrier, it is preferable to increase the amount as long as there is no problem with moldability, but in most cases, potassium permanganate is in the range of 0.05 to 0.3 in terms of KMnO ₄ /carrier weight ratio. , and phosphoric acid etc. have a weight ratio of P ₂ O ₅ /carrier.
A range of 0.04 to 0.16 is preferred. The reason for this is that when the upper limits are exceeded, moldability deteriorates, while when the lower limits are below, the air purifying agent tends to be insufficient. By the way, the oxidation potential of potassium permanganate is +0.564V when alkaline, 0.588V when neutral, and +1.695V when acidic.The potential is extremely high on the acidic side, and the oxidizing power is large, so it can be used for foul-smelling gases and
The ability to deodorize and detoxify NOx through oxidation is
Much larger than potassium permanganate alone. Additionally, potassium permanganate generally has the property of self-decomposing when manganese dioxide coexists; however, the inventors' experiments have confirmed that the presence of phosphoric acid inhibits its decomposition ( (Japanese Patent Application No. 53-85682, Japanese Patent Application No. 53-85683) Therefore, not only the life of potassium permanganate itself can be extended, but also the manganese dioxide produced by the oxidation of foul-smelling gas etc. is active and In an acidic atmosphere, the oxidation potential is still 1.23V, so the ability to absorb and remove malodorous substances such as hydrogen sulfide and mercaptans continues without loss, and the life of the oxidizing power can be substantially extended. On the other hand, phosphoric acid and the like have superior ability to absorb basic malodorous gases such as ammonia and amines compared to other mineral acids, and can synergistically improve air purification ability in combination with potassium permanganate. The air purifying agent according to the present invention can be prepared by granulating it by a known method using a suitable granulator. In most cases, this granulation can be carried out as is, but if desired, water or an appropriate amount of organic or inorganic binder may be used for granulation. After granulation, if it has a certain molding strength, it can be made into a product as is, but generally it is dried to obtain molding strength and then made into a product. In this way, the air purifying agent according to the present invention differs from cases using physical adsorption such as activated carbon or zeolite;
Since it is a unilateral reaction that absorbs or adsorbs air pollutants and malodorous substances by chemical reaction, changing them to odorless and harmless substances, there is no decrease in capacity due to adsorption equilibrium compared to physical adsorption, and the gas molecules once adsorbed are released. There is no such thing as putting on and taking off. Activated carbon can hardly remove it. SO ₂ ,NO,
Not only does it remove NO ₂ , but it also removes malodorous substances such as ammonia, nitrogen-containing organic compounds such as amines (indole, skatole, cadaverine, etc.), hydrogen sulfide, sulfur-containing organic compounds such as mercaptans, carbonyl sulfide (COS), and aldehydes. It is possible to remove unsaturated organic compounds such as , phenols, styrene, acrolene, ethylene, and acetylene. It can also be expected to have sterilizing and disinfecting effects against some bacteria, viruses, etc. As described above, when using the air purifying agent according to the present invention, most of the basic and acidic malodorous gases can be removed in one pass, but if an activated carbon filter is also placed afterwards, the removal rate can be increased with the air purifying agent of the present invention. It is possible to remove most air pollutants and malodorous substances, including organic compounds such as organic acids and organic solvents with low levels of oxidation. When using the molded product of the present invention, it can be filled into a suitable container, but for example, a simple rectangular box-shaped container with wire mesh on the top and bottom is made and air is poured into it. It can be filled with a purifying agent and used as a filter. When using this filter to purify air, the contact time with the gas to be treated is much shorter than with conventional methods, which has the advantage of making the equipment more compact and reducing pressure loss, making it economically practical. It can be said that it is a sexually rich method. The invention will now be illustrated by examples. Example Finely powdered crystals of KMnO ₄ , 85% phosphoric acid or/and
A predetermined amount of each material, 50% aluminum biphosphate and zeolite and bentonite as carriers, was thoroughly kneaded with a small amount of water, and then extruded into a cylinder with a diameter of 3 mm using an extrusion molding machine, which was then cut into a length of about 10 mm. The air purifying agent shown in Table 1 was obtained by drying. (Samples No. 1 to No. 7 in Table 1 are examples according to the present application, and No. 8 to No. 11 are comparative examples for reference.)

[Table] (i) [Example of removing NH ₃ gas] Using the air purifying agent obtained above, sample NH ₃ gas ( ₁₀ ppm,
90ppm), SV (1/H) 10000, 20000
Table 2 shows the NH ₃ gas removal rate of each purifying agent when the concentration was changed to 50,000. (SV = Passing air volume (m ³ /H) / Filling volume of purifying agent (m
³ ))

【table】

[Table] (ii) [Example 1 of NOx gas removal] The removal rate of sample NOx gas was investigated in the same manner as the NH ₃ gas removal method, and the results shown in Table 3 were obtained. [Represents NOx=NO+NO ₂ ]

[Table] (iii) [NOx gas removal example 2] When the exhaust gas treated in NOx gas removal example 1 was further passed through a filter filled with activated carbon for exhaust gas treatment, the NOx removal rate from the beginning (% ) resulted in the results shown in Table 4.

【table】

[Table] When measuring sample gases, NOx gas is measured using the chemiluminescence method, and NH ₃ gas is measured using the indophenol method or the Kitazawa gas detection tube method. (iv) [Example of SOx gas removal] Bentonite and activated carbon were each filled into a glass tube as sample No. 7 in Table 1 and a comparison sample, and the removal rate for sulfur dioxide gas (SO ₂ ) was measured. The results shown in Table 5 were obtained. It became.

[Table] (v) [Example of removing hydrogen sulfide, mercaptan, and aldehyde] Peaks at the inlet and outlet when sample No. 7 in Table 1 is filled in a glass tube and hydrogen sulfide, mercaptan, and aldehyde are passed through, respectively. When the removal rate was determined from the height or concentration, the results were as shown in Tables 6, 7, and 8 below.

【table】

【table】

[Table] (vi) [Example at nursing home N] A room with 6 bedridden elderly people (volume 35
m ³ ) One air purifier (5 m ³ /min) was installed, and the concentration of foul-smelling gas inside the room was measured when the machine was stopped and when it was running.

【table】

[Table] (vii) [Example at the toll collector in the S underground parking lot] The exhaust gas emitted when cars enter and leave the garage enters the interior of the toll collector in the underground parking lot, producing nitrogen oxides, hydrocarbons, etc. The concentration of harmful gases will increase, which will have a negative impact on the human body. One air purifier (10 m ³ /min) was installed in this room (volume approximately 60 m ³ ), and the concentration of malodorous gases in the room was measured when the operation was stopped and when the room was in operation 4 months after installation.

【table】

[Table] (viii) [Example in the animal breeding room of Company T] A breeding room that accommodates approximately 750 rats (volume: approximately 160
m ³ ) with two air purifiers (4 m ³ /min) installed.
The concentration of malodorous gas in the room was measured when the operation stopped and 30 minutes after the start of operation.

【table】

【table】

Claims (1)

[Scope of Claims] 1. An air purifying agent characterized in that potassium permanganate and phosphoric acid or/and acidic phosphate are supported and molded on an inorganic carrier composed of two or more components. 2. The inorganic carrier is at least two types of carriers selected from natural or synthetic zeolites, bentonite, ball clay, kaolin, activated clay or silicate compounds such as calcium silicate, synthetic loess, alumina, etc. The air purifying agent according to claim 1, characterized in that: 3 The weight ratio of potassium permanganate to phosphoric acid or/and acidic phosphate (P ₂ O ₅ /KMnO ₄ ) is
The air purifying agent according to claim 1, wherein the air purifying agent is in the range of 0.2 to 2. 4. The air purifying agent according to claim 1, wherein the acidic phosphate is an acidic phosphoric acid salt of aluminum, iron, or zinc.