JPH01254230A - Gas cleaning method - Google Patents

Abstract

PURPOSE:To remove toxic gas such as AsH3, PH3, SiH4, B2H6 and SeH2 efficiently, by making a gas contg. >=1 of these gases into contact with a molded body of a purifying agent comprised of mainly MnO2 and CuO and contg. Ag compounds. CONSTITUTION:Toxic components such as AsH3, PH3, SiH4, B2H6 and SeH2 contained in a gas are removed efficiently by bringing a gas contg. >=1 AsH3, PH3, SiH4, B2H6 and SeH2 into contact with a molded body of a composition mainly comprised of MnO2 and CuO and contg. Ag compounds such as Ag2CO3, Ag2SO4, AgCl, AgBr, etc., in 0.01-10.0wt.% at 0-90 deg.C.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a gas purification method, and more specifically, to a method for efficiently removing high concentration harmful gas when it suddenly leaks from a harmful gas cylinder or the like. This invention relates to a method for purifying gas.

In recent years, with the development of the semiconductor industry, the amount of extremely toxic hydride gases such as arsine, phosphine, silane, and diborane used has increased. These harmful gases are indispensable as raw material gases or doping gases in the manufacturing process of silicon semiconductors and compound semiconductors, but they are all extremely toxic, and the permissible concentration of each is 0.5% for arsine (AsH3). O5ppm, 0.3ppm for phosphine (PH3>), 5ppm for silane (SiH4')
ppm, 0.0 with diborane (B2H6). lppm, hydrogen selenide (SeH2) is 0°O5ppm. These harmful gases are usually 0.0% as shown in the table below.
1-50. It is sold commercially by filling it into a gas cylinder of grade C.

(Example of commercially available gas-filled cylinder) AsH34710 Hydrogen 75 P) Is 10 10 Hydrogen 30SiH41
0100 None 200 (g) B2H6473
Argon 20 SeH21010 Hydrogen 75 To prevent the gas from directly contaminating the outside air in the event of a leak, these cylinders are usually stored in a cylinder storage container connected to a ventilation duct called a cylinder box. Used by connecting to gas supply piping for semiconductor processes, etc. Even if the cylinder is stored in such a box, due to an unexpected accident, for example,
There is absolutely no risk of a sudden gas leak that would cause the cylinder to become empty in a short period of about 10 minutes, and there is a strong demand for safety measures that can deal with such an accident.

[Conventional technology]

There are two known methods for removing arsine, phosphine, etc. contained in gas: a wet method in which the gas is absorbed and decomposed using a scrubber, and a dry method in which the gas is removed by flowing it through a cylinder filled with an adsorbent or oxidizer. ing. In general, wet methods have drawbacks such as corrosion caused by the absorbing liquid and difficulty in post-treatment, and maintenance of the equipment is expensive.

As a dry method, gas masks filled with activated carbon are known for use in chemical warfare to remove harmful gases such as arsine and phosphine from the air. Attempts have also been made to improve the removal ability by attaching substances. For example, activated carbon is used as a carrier, and copper compounds, alkali metal compounds,
Adsorbents such as arsine and phosphine containing one or more metal compounds such as AI, Ti, V, Cr, Mn, and Fe (Japanese Unexamined Patent Publication Nos. 160535/1989 and 71039/1982) and iodine or iodine compounds There are adsorbents such as arsine and phosphine in which activated carbon is impregnated with metal sulfates and the like (Japanese Patent Application Laid-Open No. 60-71040).

In addition to those using activated carbon as a carrier, the present inventors have formulated (1) cupric oxide and (a) at least one metal oxide selected from the group consisting of silicon oxide, aluminum oxide, and zinc oxide. There is a method using a molded purifying agent (Japanese Unexamined Patent Publication No. 61-209030).

[Problem that the invention seeks to solve]

However, although the adsorbent using activated carbon as a carrier as described above can remove harmful gases such as arsine and phosphine at relatively low concentrations, it is difficult to remove harmful gases in gases with high concentrations and high flow rates. There are problems in that the activity is too low and the iodine reduced by these hydride gases tends to scatter.

On the other hand, the purifying agent disclosed in Japanese Patent Application Laid-Open No. 61-209030 by the present inventors has a much larger harmful gas removal capacity per unit weight and unit volume than conventional purifying agents, and is capable of removing a large amount of harmful gas. Can be done.

However, the removal speed of this purifying agent is not necessarily sufficient depending on the conditions, and as mentioned above, it cannot be treated quickly enough in an emergency situation such as a sudden leakage of harmful gas from a cylinder. There is a problem.

Therefore, in the event of an emergency where a large amount of harmful gas leaks, conventional abatement methods cannot be used to deal with the situation, and therefore, there has been a desire for a purification method with even better removal performance.

[Means and effects for solving the problems] As a result of intensive studies to solve these problems, the present inventors have developed a purifying agent that further contains a silver compound in a composition of manganese dioxide and copper oxide. The present invention was achieved by discovering that by using scales, highly concentrated harmful gases leaked into the air can be removed extremely efficiently.

That is, the present invention provides a gas purification method in which a gas containing one or more of arsine, phosphine, silane, diborane, and hydrogen selenide is brought into contact with a purifying agent to remove harmful gases from the gas. This is a method for purifying exhaust gas characterized by using a molded body made of (1) a composition containing manganese dioxide and copper oxide as main components and (2) a silver compound as an agent.

The purification method of the present invention can efficiently remove harmful gases such as arsine and phosphine contained in air, nitrogen, and hydrogen.

In particular, the purification method of the present invention can remove a large amount of relatively high concentration harmful gas quickly and at room temperature. For example, as described above, an excellent effect can be obtained in the rapid purification of gas (usually air) contaminated with harmful gas due to sudden leakage from a cylinder.

In the present invention, a molded body made of a composition containing manganese dioxide and copper oxide as main components (hereinafter referred to as Mn-Cu composition) containing a silver compound is used as a cleaning agent.

The form of the purifying agent may be a molded product of a mixture of an Mn-Cu based composition and a silver compound, or a molded product of an Mn-Cu based composition to which a silver compound is attached. However, for the purpose of making a relatively expensive silver compound work effectively with a small amount, it is preferable to use the latter method in which a silver compound is attached to a molded body of an Mn-Cu-based composition.

The content of manganese dioxide and copper oxide in the Mn-Cu-based composition is usually 60 wt% or more, preferably 70 wt% or more in total, and other components include aluminum, silicon, and copper oxide. Things, etc.

The ratio of copper oxide to manganese dioxide is usually 1:0.2 to 1.2, preferably 1:0.3 to 0, by weight.
．． It is said to be around 8.

In order to obtain these compositions, the respective components may be appropriately mixed and adjusted, and since these are generally commercially available as fobucalides, these may also be used.

Commercially available products are mainly ternary elements containing 60 wt% manganese dioxide and 40 wt% copper oxide. Furthermore, many commercially available multi-component systems contain manganese dioxide and copper oxide mixed with oxides such as potassium, aluminum, and silicon at a ratio of 30 wt% or less.

A molded body of such a Mn-Cu-based composition may be used as it is to remove hydride-based gases such as oarsine and phosphine, but in that case, these harmful components cannot be removed to a certain extent in the dry gas. However, the purification ability is significantly reduced for gases containing moisture, such as in normal air where the relative humidity is in the range of 30 to 100%.

In order to eliminate such drawbacks and further enhance the purification ability, in the present invention, a silver compound is further added to these Mn-Cu based compositions and used as a purification agent.

Silver compounds include silver oxide (■), silver oxide (■), and silver salts with inorganic acid silver, organic acid silver, and silver halide (
1) is mentioned. Examples of inorganic silver acids include silver carbonate, silver nitrate, silver nitrite, silver sulfate, silver sulfite, silver chlorate, silver perchlorate, silver bromate, silver iodate, silver periodate, disilver hydrogen phosphate, silver phosphate, Silver pyrophosphate, silver metaphosphate, silver tetrafluoroborate, silver hexafluorophosphate, etc. Silver halides include silver fluoride, silver chloride, silver bromide, silver iodide, and silver organic acids include silver acetate, silver chloride, silver bromide, silver iodide, etc. Examples include silver oxalate. Among these, silver(I) oxide and silver(II) oxide
> is preferred, and among the various silver salts (1), salts that are sparingly soluble or insoluble in water are generally preferred, such as silver carbonate, silver sulfate, silver phosphate, silver sulfite, silver chloride, silver bromide, and silver iodine. Examples include silver oxide, silver iodate, silver pyrophosphate, silver metaphosphate, and silver oxalate. Among these, silver oxide (It) is particularly preferred, followed by silver carbonate (■), silver oxide (I>), and mixtures thereof.

The Mn-Cu composition to which the silver compound is attached can be in various shapes such as crushed products, extrusion molded products, and tablet molded products. The size is about 4 to 20 mesh for crushed products, and 1.5 to 20 mesh for extruded products.
If it is a tablet molded product, it is usually cylindrical and has a size of about 3 to 6 mmφ x 3 to 6+ nm. However, depending on the design conditions of the device, other dimensions may be used without any problem.

Various methods are possible for attaching the silver compound to the Mn-Cu composition, and a wet method or a dry method may be used. A simple method is M
There are methods such as sprinkling a powdered silver compound onto a molded body of an n-Co-based composition, impregnating a silver compound as an aqueous slurry, or impregnating a water-soluble silver compound as an aqueous solution.

Furthermore, the silver compound may be used in a form in which a small amount of manganese dioxide, copper oxide, etc. are present in order to improve the start-up of the reaction at the initial stage of contact with gas and the adhesion to the Mn-Cu composition.

The amount of silver compound contained in the Mn-Cu composition is usually 0.01 to 10.0 wt%, preferably 0.2 to 5 wt%. If the content is less than 0.01 wt%, the gas purification efficiency will decrease, while if it is more than 10 wt%, the economic burden will increase.

The concentration of hydride gases such as arsine and phosphine that can be removed by purifying agents is usually 1% or less. At concentrations higher than this, the heat of reaction becomes large and a cooling device may be required.

The temperature of the gas brought into contact with the purifying agent is usually 0 to 90°C, preferably room temperature (10 to 50°C), and no particular heating or cooling is required. Of course, after the contact starts, the temperature increases depending on the concentration of the hydride gas due to the heat of reaction. The pressure at the time of contact is usually normal pressure, but reduced pressure or 1 kg7
It is also possible to operate under pressure, such as cm2G.

Further, the contact time may normally be 0.01 seconds or more, but preferably 0.025 seconds or more. A contact time shorter than 0.01 seconds may not provide sufficient purification ability.

There is no particular restriction on the humidity of gases such as air, nitrogen, and hydrogen to which the present invention is applied, and they may be not only in a dry state but also in a moist state. Generally, 30 to 10 corresponds to normal atmosphere.
It is often used at a relative humidity of 0%, and in such cases the water content of the purifying agent varies depending on the relative humidity of the gas and is maintained at about 5 to 30 wt%. Furthermore, the purifying agent is not adversely affected by carbon dioxide gas in the air, and the presence of these gases may even slightly increase the purifying ability depending on the situation.

In the present invention, when purifying gas containing moisture,
It is preferable that the purifying agent is kept in a water-containing state according to the humidity by bringing it into contact with an atmospheric gas having a similar humidity level in advance.

The purifying agent is usually filled in a harmful gas purifying cylinder and used as a fixed bed, but it can also be used as a moving bed or fluidized bed.

In the present invention, the density of the particles of the purifying agent is usually 0.62~
1.88g/m, preferably 0.78-1.56g/m
mQ, and the packing density when the purifying agent is packed into a purifying tube or the like is usually about 0.4 to 1.2 g/d, preferably about 0.5 to 1.0 g/-.

The purifying agent is filled into a purifying cylinder 1 as shown in the flow sheet of FIG. It is used by interposing a ventilation duct 5 connected to a blower 4.

When using a purifying agent in such a state, a heat removal means is required because a high concentration of harmful gas exceeding 1% generates a large amount of heat. However, such equipment is usually equipped with a blower of sufficient capacity to dilute the concentration to 1% or less by mixing with air even if a sudden leakage of harmful gas occurs. Specifically, many blowers with a ventilation capacity of 5 to 200 m'/mm are installed, and a large amount of leakage occurs, for example, as shown in the table above, where commercially available gas cylinders are emptied in 5 to 10 minutes. The content of harmful gases in the air is 50 to 1
It is assumed that it is about 1000 pp.

The filling length of the purifying agent in the purifying cylinder varies depending on the gas flow rate and the concentration of harmful gas, and although it cannot be generally specified, it is usually about 50 to 500 mm in practice, and the inner diameter of the purifying cylinder depends on the gas flowing inside the cylinder. The cylinder linear velocity (LV) of 0.3 to 1
．． The speed is about 5 m/sec. Generally, these are determined by the pressure drop of the packed bed, the efficiency of contact with gas, the concentration of harmful gas, etc.

〔Effect of the invention〕

According to the gas purification method of the present invention, harmful gases such as arsine, phosphine, diborane, silane, and hydrogen selenide contained in the gas, especially large amounts and relatively high concentration harmful gases, are efficiently and extremely quickly removed. Therefore, excellent effects can be obtained for abatement measures in emergencies, such as when harmful gas suddenly leaks from a gas cylinder.

Hereinafter, the present invention will be illustrated in more detail with reference to Examples.

〔Example〕

Examples 1-5 (Preparation of silver(II) oxide) 102 g of silver nitrate was dissolved in 200 g of water. Separately 90
gram of caustic soda and 150 g of potassium persulfate were dissolved in 200 g of ion-exchanged water heated to 85 DEG C. with stirring. The above silver nitrate aqueous solution was dropped into the latter while stirring while heating it to precipitate a precipitate. This product was washed by repeated decantation and water washing, and then vacuum dried at 100° C. for 3 hours to obtain 74 g of silver oxide (■) powder.

(Mn-Cu based composition) Commercially available fobucalide was used.

The composition of this material is 50% manganese dioxide (Mn02)
, copper oxide (Cub) 22%, aluminum oxide (Al
2O, ) 25%, and also contains potassium compounds. The shape is an extrusion molded product with a diameter of 1.5 mm x 3 to 10 mm.

(Preparation of purifying agent) 1000 g of the above fobucalide was dried at 120° C. for 2 hours. On the other hand, 40 g of silver (II) oxide was mixed with 500 g of water.
The suspension was stirred vigorously and sprinkled on the hobcalide in the vat to adhere the silver (II) oxide powder, and then dried at 80°C for 2 hours to remove the silver (n) oxide. A cleaning agent (granule density: 1.08 g/d) with 3.85 wt % impregnated was obtained. After that, leave it indoors and
Moisture in the atmosphere was absorbed to a moisture content of about 0 wt%.

(Activity test) The filling length is 100 mm in a quartz purification cylinder with an inner diameter of 19 mmφ.
(filling amount: 28.3 m, 19.5 g), and add 200 g of arsine or phosphine to this.
~2000ppm relative humidity 60%, temperature 25
°C air at 11.4~20.4 (1/rim
It was circulated at a flow rate of (empty cylinder linear velocity LV67-120cm/5ec). A portion of the outlet gas of the purifying agent was sampled, and the time required for the concentration of arsine or phosphine in the outlet gas to rise to 25 ppb (effective treatment time) was measured by cold atomic absorption spectrometry.

The results are shown in Table 1.

Table 1 1 Arsine 1000 67
432 Horn 2000
67 173 Horn
200 67 2=17) 14 nol 1000
120 175 Phosphine 10
00 67 22 Examples 6-8 Instead of arsine and phosphine, diborane, silane,
The effective treatment time was measured for air containing hydrogen selenide in the same manner as in Examples 1 to 5.

However, the gas concentration at the exit of the purification cylinder was measured using a detection tube for diborane and hydrogen selenide, and the time (effective processing time) until these gases were detected was determined. The detection tube for diborane is made by Tregel, and the detection limit is 0. The detection limit for hydrogen selenide is 1 ppm by Kyimei Rikagaku Co., Ltd.

Regarding silane, we used a color-changing reagent in which basic copper carbonate was supported on alumina, but the detection limit for this was 10p.
It is pm.

The results are shown in Table 2.

Table 2 6 Silane 1000 67 1
57 Diborane 1000 67
218 Hydrogen selenide 1000 67
55 Comparative Example 1.2 A commercially available fobcalide of the same kind as that used in Example 1 was dried and left indoors to have a moisture content of about 10%, which was used as a purifying agent, and arsine was prepared in the same manner as in Example 1. The effective treatment time was measured for and phosphine.

The results are shown in Table 3.

Table 3 1 Arsine 1000 67 0
．． 52 Phosphine 1000 67
0.5 Example 9.10 The effective treatment time was measured in the same manner as in Example 1 except that nitrogen containing 1 arsine and OOOppm and hydrogen were used instead of air.

The results are shown in Table 4.

Table 4 9 Nitrogen Arsine 1000
67 1510
Hydrogen Phosphine 1000
67 16 Example 1
1.12 (Preparation of silver oxide (If) containing manganese dioxide) 200-
The procedure for preparing silver (II) oxide in Example 1 was repeated, except that 2.27 g of manganese nitrate was added to a silver nitrate aqueous solution in which 102 g of silver nitrate was dissolved in water.
．． A silver (n) oxide powder containing 5 wt% manganese dioxide was prepared.

(Preparation of purifying agent) This powder was dry sprinkled on the same kind of hobcalide as used in Example 1, stirred well and attached to about 3.85 wt.
A cleaning agent loaded with % silver (II) oxide and a small amount of manganese dioxide was prepared. Examples 1 to 5 using this purifying agent
The effective processing time was measured in the same manner as above. The results are shown in Table 5.

Table 5 11 Arsine 1OoO6745 12 Phosphine 1000 67 2
3 Example 13.14 (Mn-Cu-based composition) Instead of the fobucalide of Example 1, a commercially available fobucalide having a different composition was used. Its composition is manganese dioxide (
Mn02) 58%, copper oxide (Cub) 38%, and other potassium compounds, etc., and there are two types of pellets: crushed 8 to 14 meshes and cylindrical pellets of 4.8 mmφ x 4°8 ml Tl. was used.

The latter pellet was divided into quarters before use.

(Preparation of purifying agent) Silver (II) oxide was 3.85% by wet method in the same manner as in Example 1.
In order to adjust the impregnated purifying agent so as to have a concentration of 100% by weight (activity test), the effective treatment time of each was measured in the same manner as in Example 1 using this purifying agent.

The results are shown in Table 6.

Table 6 13 *1) Arsine 1000 67
3514 *2) Horn 100
0 67 18*1) 8~1
Example of hobcalide of 4-mesh crushed product 15 Activated manganese dioxide 100g, copper oxide (Cub) 40
g and alumina sol (20 g as pure A1□0.)
60 g of silver (n) oxide powder and a small amount of water were added to the mixed composition and kneaded, and then dried in a molding plate to form a 4 mmφ x 4 mm pellet containing 5.88 wt% of silver (II) oxide. The effective treatment time was measured in the same manner as in Example 1 using a prepared purifying agent containing the filtrate, which was further crushed into 4 to 20 meshes.

The results are shown in Table 7.

Table 7 Comparative Examples 3-5 Particle size is 6-10 in carrier instead of Mn-Co composition
The effective treatment time was measured in the same manner as in Example 1 for a mesh of activated carbon, α-alumina, and molecular sieve 5A impregnated with 4.25 wt % of silver oxide (If).

The results are shown in Table 8.

Table 8 3 Arsine 1000 67 Activated carbon 04 Noj 1000 67
α-Alumina O Example 16.17 Silver oxide (If
) was changed to 0.5 and 2.0 wt%, respectively, and the effective processing time was measured.

The results are shown in Table 9.

Table 9 16 Arsine 1000 67 2.0
3017 Noah 1000
67.0.5 20 Example 18 When air containing 1% carbon dioxide gas was passed through the same kind of purifying agent used in Example 1 for 8 hours to see the effect of carbon dioxide gas in the air, the purifying agent became endothermic. did.

Thereafter, the effective treatment time was measured under the same conditions as in Example 1.

The results are shown in Table 10.

Table 10 Examples 19-23 (Preparation of silver (I) oxide) 102 g of silver nitrate was dissolved in 200 g of water. Separately 90
200g of ion-exchanged water heated to 85°C with caustic soda
Dissolved while stirring. The above silver nitrate aqueous solution was dropped into the latter while stirring while heating it to precipitate a precipitate. After washing this product by repeating decantation and water washing, it was vacuum dried at 100° C. for 3 hours to obtain 69 g of silver (I) oxide powder.

(Mn-Cu-based composition) The same type of commercially available fobucalide used in Example 1 was used.

(Preparation of purifying agent) 1000 g of fobucalide was dried at 120° C. for 2 hours. On the other hand, a suspension of 40 g of silver oxide (1) in water 5007 was sprinkled on the hobcalide in the vat while stirring vigorously to adhere the silver oxide (1) powder.
Next, it was dried at 80°C for 2 hours to remove silver oxide (1).
A purifying agent was obtained in which 5 wt% of 3J was impregnated. Thereafter, it was left indoors to absorb atmospheric moisture to a water content of about 10 wt%.

(Activity test) It was carried out in the same manner as in Example 1.

The results are shown in Table 11.

Table 11 19 Arsine 1000 67 2
g20/ノ20006715 21 1ノ 200 67
14022 1no 1000
120 1023 Phosphine
1000 67 12 Examples 24-2
6 Using the same type of cleaning agent as in Examples 19 to 23, the effective treatment time was measured in the same manner as in Examples 1 to 5 for air containing diborane, silane, and hydrogen selenide instead of arsine and phosphine.

The results are shown in Table 12.

Table 12 24 Silane 1000 67
825 Diborane 1000 67
1326 Hydrogen selenide 1000 67
32 Example 27.28 (Mn-Cu based composition) The same type of fobucalide as used in Example 13.14 was used.

(Preparation of purifying agent) Silver (I) oxide was 3.85% by wet method in the same manner as in Example 19.
The attached purifying agent was adjusted to have a wt%.

(Activity Test) Using this purifying agent, the effective treatment time of each was measured in the same manner as in Example 1.

The results are shown in Table 13.

Table 13 27 *1) Arsine 1000 67
2728 *2) Horn 1000
67 14*1) 8-14
Comparative example of hobcalide of mesh crushed product 6-8 Activated carbon with particle size of 6-10 mesh, α-alumina, molecular sieve 5 as carrier instead of Mn-Cu composition
The effective treatment time was measured in the same manner as in Example 1 using A and adding 4 wt % of silver oxide (1) thereto.

The results are shown in Table 14.

Table 14 6 Furushi'/1000 67
Activated carbon 07 horn 1000
67 α-Alumina 0 Example 29.3
0 Silver oxide (1) was added to the same kind of fobcalide as used in Example 1.
The effective processing time was measured for each of the samples in which the amount of impregnation was changed to 0.5 and 2.0 wt%.

The results are shown in Table 15.

Table 15 29 Arsine 1000 67 2.0
2230 Horn 1000
67 0.5 11 Examples 31 to 35 (Mn-Cu based composition) The same type of commercially available fobucalide used in Example 1 was used.

(Preparation of purifying agent) 300 g of the above fobucalide was dried at 120° C. for 2 hours. On the other hand, a suspension of 12 g of silver carbonate (I) in 100 g of water was sprinkled onto the hobcalide in the vat while stirring vigorously to adhere the silver carbonate powder. At this time, the solids in the suspension remain on the vessel wall, so
The operation of adding 00- and spraying while stirring vigorously was repeated twice, and finally the silver carbonate was washed and sprayed with water 50- to impregnate the entire amount of silver carbonate. 312 g of a purifying agent impregnated with 3.85 wt% of (I) was obtained. Thereafter, it was left indoors to absorb atmospheric moisture to a moisture content of about 8%.

(Activity test) The effective processing time was measured in the same manner as in Example 1.

The results are shown in Table 16.

Table 16 31 Arsine 1000 67
3932 Horn 2000 6
7 1533 II
200 67 20034
Horn 1000 120
1535 Phosphine 1000 6
7 16 Examples 36 to 38 Using the same type of purifying agent as in Examples 3 and 1 to 35, arsine,
In the same manner as in Examples 1 to 5, using air containing diborane, silane, and hydrogen selenide instead of phosphine,
The effective processing time was measured.

The results are shown in Table 17.

Table 17 36 Silane 1000 67
1037 Diborane 1000 67
1638 Hydrogen selenide 1000
67 30 Example 39 Instead of using silver carbonate (1) or silver oxide (■) alone as the silver compound, a mixture of the two in a ratio of 1=1 and suspension in water was used in Example 1. The effective treatment time was measured in the same manner as in Example 1, except that a purifying agent impregnated with 3.85% silver compound was used and sprayed on the same type of commercially available hobcalide.

The results are shown in Table 18.

Table 18 Example 40.41 (Preparation of purifying agent) 200 g of fobucalide of the same type as used in Example 1 was
It was dried at 0°C for 2 hours. 48 g of a silver nitrate aqueous solution prepared by dissolving 20 g of silver nitrate in 100 g of water was sprayed onto the dried fobcalide using a spray sprayer. This Pocalite impregnated with silver nitrate was dried at 80° C. for 10 hours to obtain 208 g of a purifying agent impregnated with 3.85 wt % of silver nitrate.

This product was left in the air to become a product containing about 8 wt % water, and then the effective treatment time was measured in the same manner as in Examples 1 to 5.

The results are shown in Table 19.

Table 19 40 Arsine 1000 67
1241 Phosphine 1000. 67
7 Example 42.43 (Mn-Cu based composition) The same fobucalide as used in Example 13.14 was used.

(Preparation of purifying agent) Silver carbonate (I > 3.85 w) was prepared in the same manner as in Example 1 using a wet method.
The attached purifying agent was adjusted so that it became t.

(Activity Test) Using this purifying agent, the effective treatment time of each was measured in the same manner as in Example 1.

The results are shown in Table 20.

Table 20 42 *1) Arsine 1000 67
3243 *2) NoJ 1000
67 15*1) 8-14
Comparative examples of hobcalide of crushed mesh products 9-11 Particle size of 6-10 in carrier instead of Mn-Cu-based composition
Using mesh activated carbon, α-alumina, and molecular sieve 5A, 4°25wt of silver carbonate (I) was added.
The effective processing time was measured in the same manner as in Example 1 for the sample with 5% adhesion.

The results are shown in Table 21.

Table 21 9 Arsine 1000 67 Activated carbon
010 #1000 67
α-Alumina O Example 44.45 Silver carbonate (I) was added to the same kind of hobcalide as used in Example 1.
The effective processing time was measured for each of the samples in which the amount of impregnation was changed to 0.5 and 2.0 wt%.

The results are shown in Table 23.

Table 23 44 Arsine 1000 67 2
2545 Horn 1000
67 0.5 12 Examples 46~
51 Silver sulfate, silver chloride, silver bromide, silver iodide, silver phosphate, silver iodate was used in place of silver carbonate <I) used in Example 19.
After drying, the effective treatment time was measured in the same manner as in Examples 1 to 5 while absorbing atmospheric moisture to a moisture content of about 8%.

The results are shown in Table 24.

Table 24 46 Silver sulfate Arsine 1000 67
2247 Silver chloride II 1000
67 1848 Silver Bromide II 1
000 67 2149 Silver iodide 1000 67 2250 Silver phosphate horn 1000 67 16
51 Silver iodate II 1000 6
7 20 Examples 52.53 In Example 40.41, 3.85 wt% of silver perchlorate and silver acetate were impregnated instead of silver nitrate, and after drying, 8 wt% of moisture in the atmosphere was absorbed again. A cleaning agent was prepared and the effective treatment time was measured in the same manner as in Examples 1-5.

The results are shown in Table 25.

Table 25 52 Silver perchlorate Arsine 1000 67
1053 Silver acetate No.I 100
0 67 12

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an example in which a purifying agent for harmful gases is filled in a purifying cylinder and interposed in a gas flow path. The numbers in the drawings are as follows. 1. Purifying agent 2. Gas cylinder 3, cylinder box 4. Blower and 5. Ventilation duct patent applicant: Japan Bionics Co., Ltd. Representative: Ryo Yamazaki − Representative: Patent attorney: Sadafumi Kobori

Claims (1)

[Claims] In a gas purification method in which a gas containing one or more of arsine, phosphine, silane, diborane, and hydrogen selenide is brought into contact with a purifying agent to remove harmful gases from the gas, as a purifying agent (1) A method for purifying gas, which comprises using a molded article made of a composition containing manganese dioxide and copper oxide as main components and (2) a silver compound.