JP2000325780A - Nitrogen oxide and/or sulfur oxide adsorbent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a best-suited adsorbent which adsorbs and removes especially a low concentration of nitrogen oxides or sulfur oxides as an adsorbent of the nitrogen oxides or the sulfur oxides containing an alkaline metal element by heating the adsorbent in the presence of a reducing agent. SOLUTION: This nitrogen oxide and/or a sulfur oxide adsorbent contains an alkaline metal element and is heated in the presence of a reducing agent. In addition, gas containing the nitrogen oxide and/or the sulfur oxide is brought into contact with the adsorbent to adsorb and remove the nitrogen oxide and/or the sulfur oxide. Further, in the method for bringing the gas containing the nitrogen oxide and the sulfur oxide into contact with the adsorbent for the nitrogen oxide, after removing the sulfur oxide from the gas, to adsorb and remove the nitrogen oxide, this adsorbent is used as an adsorbent for the nitrogen oxide. Besides, the adsorbent contains the alkaline metal element (Li, An, K, Rb and Cs) and at least one kind of an element selected from among manganese, nickel, cobalt, iron and lead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adsorbent for nitrogen oxides and / or sulfur oxides and a method for removing nitrogen oxides and / or sulfur oxides using the adsorbent.

[0002]

2. Description of the Related Art With respect to a method of removing nitrogen oxides from a fixed nitrogen oxide source such as a boiler, conventionally, ammonia has been selectively reduced by using ammonia as a reducing agent to remove harmless nitrogen. The catalytic reduction method of converting to water is widely used as the most economical method.

[0003] The concentration of nitrogen oxides contained in ventilation gas or air in road tunnels, sheltered roads, deep underground spaces, road intersections, etc., and gas exhausted from combustion equipment used in homes is as follows. , 5
ppm, which is significantly lower than the concentration of nitrogen oxides in the boiler exhaust gas, the gas temperature is room temperature, and the amount of gas is enormous. For this reason, for example, in order to remove nitrogen oxides efficiently by applying the above-mentioned catalytic reduction method to the ventilation gas of a road tunnel, the temperature of the ventilation gas is set to 300.
C. or more, and as a result, a large amount of energy is required. Therefore, it is economically problematic to apply the above catalytic reduction method as it is.

[0004] Under such circumstances, it is desired to efficiently remove nitrogen oxides from exhaust gas having a low nitrogen oxide concentration, for example, 5 ppm or less, such as ventilation gas for road tunnels as described above.

Accordingly, the present applicant has proposed an adsorbent suitable for adsorbing and removing nitrogen oxides from the above-mentioned low-concentration nitrogen oxide-containing gas (Japanese Patent Laid-Open No. 10-12810).
5, JP-A-10-192498, JP-A-10-3094
35, JP-A-11-28351, JP-A-11-2835
2 and Japanese Patent Application No. 10-340140). In addition, as a method for efficiently removing nitrogen oxides from a gas containing sulfur oxides in addition to nitrogen oxides, the present applicant removes sulfur oxides in advance and then contacts the nitrogen oxide adsorbent. A method of adsorbing and removing nitrogen oxides has been proposed (JP-A-10-76136). Furthermore, the present applicant has also proposed a method of heating and regenerating an adsorbent whose performance has been reduced by use in the presence of a reducing agent (Japanese Patent Application No. 10-3401).
38).

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a low concentration nitrogen oxide and / or sulfur oxide suitable for adsorbing and removing nitrogen oxides and / or sulfur oxides, in particular, having a low concentration of about 5 ppm or less. It is an object of the present invention to provide an adsorbent suitable for adsorption and removal, and a method for removing nitrogen compounds and / or sulfur oxides using the adsorbent.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the following adsorbents can solve the above problems, and have completed the present invention based on this finding.

That is, the present invention provides a nitrogen oxide and / or sulfur oxide adsorbent containing an alkali metal element, which is heat-treated in the presence of a reducing agent. And / or adsorbents for sulfur oxides.

Further, the present invention is characterized in that a gas containing nitrogen oxides and / or sulfur oxides is brought into contact with the adsorbent to adsorb and remove the nitrogen oxides and / or sulfur oxides. And / or a method for removing sulfur oxides.

Further, the present invention provides a method for adsorbing and removing nitrogen oxides by removing a sulfur oxide from a gas containing a nitrogen oxide and a sulfur oxide and then contacting the gas with a nitrogen oxide adsorbent. The use of the above adsorbent as the adsorbent for nitrogen oxides in the method for removing nitrogen oxides and sulfur oxides.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The adsorbent of the present invention adsorbs nitrogen oxides and / or sulfur oxides at a low concentration of 5 ppm or less, typically nitrogen oxides, or nitrogen oxides and sulfur oxides. It is for. This nitrogen oxide is shown as NOx, specifically, NO and NO ₂
Can be mentioned. Also, the sulfur oxides are those represented by SOx, can be specifically exemplified SO _2. The adsorbent of the present invention is particularly excellent in adsorbing and removing NO ₂ .

The adsorbent of the present invention is a nitrogen oxide and / or sulfur oxide adsorbent containing an alkali metal element as an essential component, which is subjected to heat treatment in the presence of a reducing agent.

Representative examples of the nitrogen oxide and / or sulfur oxide adsorbent containing an alkali metal element of the present invention include the following. As for the ratio, the components (1), (2) and (3) are calculated as oxides, and the component (4) is calculated as metal.

<Adsorbent (A)> (1) Alkali metal element (Li, Na, K, Rb, C
s) and (2) an adsorbent containing at least one element selected from manganese, nickel, cobalt, iron and lead.

Regarding the ratio of each component, component (1) is 1
-30% by weight, preferably 1-20% by weight, and component (2) is 70-99% by weight, preferably 80-99% by weight (total 100% by weight; the same applies hereinafter).

<Adsorbent (B)> (1) an alkali metal element, (2) manganese, nickel,
At least one element selected from cobalt, iron and lead, and (3) titanium, silicon, aluminum, zirconium and alkaline earth metal elements (Be, Mg, C
adsorbent containing at least one element selected from a, Sr, Ba);

Regarding the ratio of each component, component (1) is 1
% To 30% by weight, preferably 1 to 20% by weight, component (2) is 0.5 to 89% by weight, preferably 1 to 75% by weight, and component (3) is 10 to 98.5% by weight. , Preferably 20 to 98% by weight.

<Adsorbent (C)> (1) an alkali metal element, (2) manganese, nickel,
At least one element selected from cobalt, iron and lead; (3) at least one element selected from titanium, silicon, aluminum, zirconium and alkaline earth metal elements; and (4) platinum, gold, ruthenium and rhodium And an adsorbent containing at least one element selected from palladium.

Regarding the ratio of each component, component (1) is 1
-30% by weight, preferably 1-20% by weight, component (2)
Is from 0.5 to 89% by weight, preferably from 1 to 75% by weight, and component (3) is from 10 to 98.5% by weight, preferably from 2 to
0 to 98% by weight, and component (4) is 0.01 to 10% by weight, preferably 0.05 to 5% by weight.

The form of the alkali metal element of the component (1) is not particularly limited, and may be any form as long as it can adsorb nitrogen oxides and / or sulfur oxides. For example, it is contained in the form of hydroxide, carbonate or bicarbonate. Starting materials for component (1) include hydroxides, carbonates, bicarbonates, nitrates,
Organic acid salts such as nitrite, acetate and oxalate can be used.

The form of the components (2), (3) and (4) is not particularly limited, and may be in any form as long as the function of adsorbing nitrogen oxides and / or sulfur oxides is obtained. .

In the case of the component (2), for example, a metal, an oxide,
It is contained as a composite oxide, a composite oxide with an alkali metal or an alkaline earth metal, a double salt, or the like. As the starting materials, metals, oxides, hydroxides, carbonates, nitrates, sulfates, halides, organic metal salts, and organic acid salts such as acetic acid and oxalate of each element can be used.

In the component (3), in the case of titanium, silicon, aluminum and zirconium, for example, an oxide,
It is contained as complex oxides and various zeolites. As the starting materials, oxides, hydroxides, nitrates, sulfates, halides, phosphates and the like of each element can be used. In the case of an alkaline earth metal, it is contained, for example, as an oxide, hydroxide, carbonate, phosphate, sulfate and the like. As the starting materials, oxides, hydroxides, carbonates, sulfates, halides, phosphates and the like can be used. Among the components (3), zirconium and alkaline earth metal elements are preferably used in that an adsorbent having excellent durability can be obtained. In the case of the component (4), for example, it is included as a metal, an oxide, a composite oxide, or the like. As the starting materials, oxides, hydroxides, nitrates, sulfates, halides, organic metal salts, ammonium complexes and the like of each element can be used.

The adsorbent before the reduction treatment of the present invention can be prepared by a method generally used for preparing this kind of adsorbent. For example, a typical method for preparing an adsorbent containing the components (1), (2), (3) and (4) will be described below.
The present invention is not limited to this.

Component (1), Component (2) and Component (4)
Aqueous solution or powder of the starting material is added to the above component (3) together with a commonly used molding aid, mixed, stirred and molded by an extruder. The obtained molded product is 50-
After drying at 120 ° C., firing may be performed at 200 to 600 ° C., preferably 250 to 500 ° C., for 1 to 10 hours, preferably 2 to 6 hours in air or an inert gas such as nitrogen. In addition, a molded body containing at least one of the components (1), (2) and (4) and the component (3) is prepared in advance, and the remaining components are impregnated and supported on the molded body. It may be prepared in the same manner as described above.

The adsorbent of the present invention comprises the adsorbent (A)
It is obtained by heat-treating an adsorbent such as (C) containing an alkali metal element as an essential component in the presence of a reducing agent.

This reducing agent means hydrogen and a combustible organic compound. As the combustible organic compound, hydrocarbons, preferably saturated or unsaturated hydrocarbons having 1 to 4 carbon atoms, can be used. Thus, in the present invention,
Hydrogen or hydrocarbons, especially hydrogen, are suitably used as the reducing agent.

Representative examples of the above hydrocarbons include saturated or unsaturated hydrocarbons such as methane, ethane, propane, butane, ethylene, propylene and butadiene.

The reducing agent is usually diluted with another gas and used as a mixed gas with an inert gas such as nitrogen. Specifically, when hydrogen is used as the reducing agent, it is used as a mixed gas of hydrogen and an inert gas such as nitrogen or helium. The concentration of hydrogen in the mixed gas is usually 0.1 to 20% by volume, preferably 0.5 to 1% by volume.
0% by volume. Although a mixed gas with air can be used, there is a danger of explosion. Therefore, it is generally preferable to use the mixed gas with the inert gas as described above. In the case of a combustible organic compound, it is used as a mixed gas with an inert gas such as nitrogen. The concentration of the combustible organic compound in the mixed gas is usually from 0.001 to 1% by volume, preferably from 0.01 to 0.5% by volume.

Examples of the gas that can be used for diluting the reducing agent include the above-mentioned inert gas such as nitrogen and helium and air, as well as water vapor (H ₂ O) and carbon dioxide gas. Thus, typical examples of the mixed gas include a combination of hydrogen and an inert gas, or a combination of a combustible organic compound and an inert gas.

The heating temperature is usually from 200 to 600 ° C., preferably from 300 to 500 ° C., and more preferably from 30 to 500 ° C.
0-400 ° C. The adsorbent to be subjected to the reduction treatment is usually at room temperature, but the rate of temperature rise up to the heating temperature is not particularly limited, and can be appropriately determined. The heating time cannot be specified unconditionally, but is usually 30 minutes to 10 hours,
Preferably, it can be appropriately selected in the range of 30 minutes to 5 hours.

The heat treatment of the present invention is preferably performed under ventilation of a reducing agent. In the case where the heat treatment is performed under ventilation of the reducing agent, the degree of ventilation is not particularly limited, and the condition may be such that a new reducing agent is supplied.

The shape of the adsorbent of the present invention is not particularly limited, and can be appropriately selected from a column, a cylinder, a sphere, a plate, a honeycomb, and other integrally molded products. For this molding, a general molding method, for example, tablet molding, extrusion molding or the like can be used. In the case of a spherical shape, the average particle size is usually 1 to 10 mm. In the case of a honeycomb-shaped adsorbent, it is the same as a so-called monolith carrier, and can be manufactured by an extrusion molding method, a method of winding a sheet-shaped element, or the like. The shape of the gas passage port (cell shape) may be any of a hexagon, a quadrangle, a triangle, or a corrugation. Cell density (number of cells /
The unit sectional area is usually 25 to 800 cells / square inch, and preferably 25 to 500 cells / square inch.

According to the method of the present invention, a gas containing nitrogen oxides and / or sulfur oxides is brought into contact with the adsorbent to adsorb the nitrogen oxides and / or sulfur oxides and purify the gas. The nitrogen oxide (NOx) is at least one of nitrogen monoxide and nitrogen dioxide, and the sulfur oxide (SOx) is sulfur dioxide. A typical example of the above-mentioned gas is a ventilation gas or an atmospheric gas from the above-mentioned road tunnel or the like, and the method of the present invention is a method for producing a nitrogen oxide from a gas having a low nitrogen oxide or sulfur oxide concentration of 5 ppm or less. And / or It is suitably used for adsorption removal of sulfur oxides.

The method for contacting the above gas with the adsorbent is not particularly limited, and is usually carried out by introducing a gas into a layer made of the adsorbent. Since the treatment conditions differ depending on the properties of the gas to be treated and the like, they cannot be specified unconditionally. For example, the temperature of the gas supplied to the adsorbent layer is usually
The temperature is 0 to 100 ° C, and particularly preferably 0 to 50 ° C. The space velocity (SV) of the gas supplied to the adsorbent layer
Is usually a 500~50000hr ^-1 (STP), preferably in the range of 2000~30000hr ^-1 (STP).

When purifying a gas by efficiently removing nitrogen oxides from a gas containing sulfur oxides in addition to nitrogen oxides, the sulfur oxides are removed in advance and then contacted with the adsorbent of the present invention. By adsorbing and removing nitrogen oxides, the durability of the adsorbent is improved, and nitrogen oxides can be effectively removed over a long period of time.

The method of removing the sulfur oxide is not particularly limited, and a method of removing the gas by washing with water, a method of bringing the gas into contact with an adsorbent for adsorbing the sulfur oxide, and the like can be used. Above all, a method using an adsorbent for sulfur oxides is preferably used from the viewpoint of a compact apparatus and low energy consumption.

As the adsorbent for sulfur oxide, SOx
Any adsorbent may be used as long as it can adsorb, and among them, an adsorbent containing at least one selected from activated carbon, transition metals, alkali metals and alkaline earth metals is suitably used. Representative examples of transition metals include Ni, Co,
Examples include Fe, Mn, Cr, Mo, W, V, Nb, Zn, and Cu. Representative examples of alkali metals and alkaline earth metals include Li, Na, and K, respectively.
And Mg, Ca, Ba. There is no particular limitation on the form of these elements in the adsorbent.
Any form may be used as long as it can adsorb x. Specific examples include oxides, carbonates, sulfates, chlorides and hydroxides.

The sulfur oxide adsorbent is used as a carrier
Alkaline earth metal salts, alumina, silica, titania, zirconia, silica-alumina, alumina-zirconia,
It may contain at least one of silica-titania, silica-zirconia and titania-zirconia.

Thus, in a preferred embodiment of the present invention, a gas containing nitrogen oxides and sulfur oxides is first contacted with an adsorbent for sulfur oxides to adsorb and remove sulfur oxides, and then the adsorbent of the present invention To purify the gas by adsorbing and removing nitrogen oxides. Thereby, the durability of the adsorbent of the present invention is improved.

[0041]

The adsorbent of the present invention comprises nitrogen oxides and / or
Or, it has high adsorption performance to sulfur oxides, particularly low concentration nitrogen oxides and / or sulfur oxides, and shows excellent durability.

In purifying a gas containing nitrogen oxides and sulfur oxides, the sulfur oxides are removed in advance, and then contacted with the adsorbent of the present invention to remove the nitrogen oxides. And nitrogen oxides can be effectively adsorbed and removed over a long period of time.

[0043]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 1000 g of manganese carbonate was mixed well with a kneader while adding an appropriate amount of water, and then 5 mm in diameter and 5 mm in length were formed by an extruder.
mm pellets. 100 ℃
And then calcined at 500 ° C. for 3 hours in an air atmosphere. Next, the pellet was impregnated with a 4N-potassium carbonate aqueous solution for 2 minutes, and then dried at 120 ° C for 5 hours. The composition of the pellets is Mn: K (MnO ₂ : K ₂ O
As) = 89.5: 10.5 (% by weight).

The above pellets were heated at 400 ° C. for 2 hours with hydrogen /
The reduction treatment was performed in an atmosphere of nitrogen (5/95% by volume) to obtain an adsorbent (1).

Examples 2 to 5 The same procedures as in Example 1 were carried out except that basic nickel carbonate, basic cobalt carbonate, iron hydroxide and basic lead carbonate were used instead of manganese carbonate in Example 2. Pellets having the composition shown were produced and subsequently subjected to reduction treatment in the same manner as in Example 1 to obtain adsorbents (2) to (5).

Example 6 286 L of aqueous ammonia (NH ₃ , 25%) was added to 400 L of water.
And 24 kg of Snowtex NCS-30 (silica sol, Nissan Chemical Co., Ltd., containing about 30% by weight of SiO ₂ ) was added thereto. 153 L of an aqueous solution of titanyl sulfate in sulfuric acid (containing 250 g / L as TiO _{2 and a} total sulfuric acid concentration of 1,100 g / L) was added to 300 L of water, and a titanium-containing aqueous solution of sulfuric acid was gradually added to the resulting solution with stirring. Then, a coprecipitation gel was obtained. Leave it for 15 hours and
It was obtained iO ₂ -SiO ₂ gel. This gel was filtered, washed with water, and then dried at 200 ° C. for 10 hours. Then 600 ° C
For 6 hours in an air atmosphere, further pulverized using a hammer mill, and classified using a classifier to obtain a powder having an average particle diameter of 10 μm. The composition of the obtained powder (hereinafter referred to as TS-1) was Ti: Si = 4: 1 (atomic ratio).

226.2 g of manganese carbonate, TS-1
After 828 g of this was mixed well with a kneader while adding an appropriate amount of water, it was formed into a pellet having a diameter of 5 mm and a length of 5 mm by an extruder. The pellets were dried at 100 ° C. for 10 hours and then fired at 350 ° C. for 3 hours in an air atmosphere.
The pellets were further impregnated with a 4N-potassium carbonate aqueous solution for 2 minutes, and then dried at 120 ° C for 5 hours. The composition of this pellet is Mn: K: TS-1 (MnO2: K2O: T
(As S-1) = 15.0: 12.6: 72.4 (% by weight).

Subsequently, the pellets were reduced at 400 ° C. for 2 hours in an atmosphere of hydrogen / nitrogen (5/95% by volume) to obtain an adsorbent (7).

Examples 7 to 11 In the same manner as in Example 6, except that titanium oxide, aluminum oxide, zirconium oxide, calcium carbonate and barium carbonate were used in place of TS-1, the compositions shown in Table 1 were used. Pellets were manufactured, and then these pellets were subjected to reduction treatment in the same manner as in Example 6 to obtain adsorbents (7) to (1
1) was obtained.

Example 12 1.5 g of ruthenium oxide (manufactured by Tanaka Kikinzoku Co., Ltd., containing 65% by weight of ruthenium metal), manganese carbonate 198.
3g, 800g calcium carbonate and 73.3 potassium carbonate
g of potassium carbonate dissolved in 100 g of water,
After mixing well with a kneader while adding an appropriate amount of water,
It was formed into a pellet having a diameter of 5 mm and a length of 5 mm by an extruder. The pellet was dried at 100 ° C. for 10 hours, and then fired at 500 ° C. for 3 hours in an air atmosphere. The composition of the pellets is Ru: Mn: K: Ca (Ru: MnO
_2: K ₂ O: as CaO) = 0.2: 23.1: 7 .
7: 69.0 (% by weight).

Subsequently, the pellets were reduced at 400 ° C. for 2 hours in an atmosphere of hydrogen / nitrogen (5/95% by volume) to obtain an adsorbent (12).

Example 13 Pellets having the composition shown in Table 1 were produced in the same manner as in Example 12 except that basic nickel carbonate was used in place of manganese carbonate. The treatment gave an adsorbent (13).

Examples 14 to 17 In the same manner as in Example 13, except that an aqueous solution of platinum nitrate, an aqueous solution of gold hydrochloride, an aqueous solution of rhodium nitrate and an aqueous solution of palladium nitrate were used instead of ruthenium oxide, the compositions shown in Table 1 were used. Pellets were produced and subsequently subjected to a reduction treatment in the same manner as in Example 13 to obtain adsorbents (14) to (17).

Comparative Examples 1 to 3 In Examples 1, 6 and 13, the last hydrogen / nitrogen (5
/ 95% by volume) in the same manner as in Examples 1, 6 and 13 except that the reduction treatment was not performed in an atmosphere of (comparative 1), (comparative 2) and (comparative 2), respectively. The pellet of (Comparative 3) was obtained.

The adsorbent (1) obtained as described above
Table 1 summarizes the compositions of (17) and the comparative adsorbents (Comparative 1) to (Comparative 3).

[0057]

[Table 1]

In Table 1, components (1) to (4)
Are shown as compounds (oxides) and metals that are the basis for calculating the composition.

Example 18 Adsorbents (1) to (17) and Comparative Adsorbent (Comparative 1)
The nitrogen oxide adsorption ability and sulfur oxide adsorption ability of (Comparative 3) were evaluated by the following two methods.

(Evaluation Method (1)) A glass reaction tube having an inner diameter of 30 mm was filled with 35 ml of an adsorbent. A synthesis gas (A) having the following composition was introduced into the adsorbent layer under the following conditions.

Synthesis gas (A) composition Nitric oxide (NO): 0.9 ppm, nitrogen dioxide (NO)
₂ ): 0.1 ppm, sulfur dioxide (SO ₂ ): 0.05 p
pm, H ₂ O: 1.9% by volume, remaining: air treatment conditions Gas amount: 17.3 NL / min, treatment temperature: 25 ° C., space velocity (SV): 30,000 hr ⁻¹ (STP), gas humidity: 60% RH One hour after the introduction of the syngas, nitrogen oxides (N 2) in the syngas at the inlet and the outlet of the adsorbent layer
O, NO ₂ ) concentration by a chemiluminescent NOx meter,
The sulfur oxide (SO ₂ ) concentration was measured by an ultraviolet absorption SO ₂ meter, and the NO, NO ₂ and SO ₂ removal rates were calculated according to the following equation.

NO removal rate (%) = {(inlet NO concentration-outlet NO concentration) / (inlet NO concentration)} × 100 NO ₂ removal rate (%) = ｛(inlet NO ₂ concentration−outlet NO ₂ concentration) / (Inlet NO ₂ concentration)｝ × 100 SO ₂ removal rate (%) = {(Inlet SO ₂ concentration−Outlet SO ₂ concentration) / (Inlet SO ₂ concentration)} × 100 (Evaluation method (2)) After the accelerated durability test, the adsorbents were evaluated for nitrogen oxide adsorbing ability and sulfur oxide adsorbing ability in the same manner as in the evaluation method (1).

<Accelerated endurance test>
It was filled in a 0 mm glass reaction tube. A synthesis gas (B) having the following composition was introduced into the adsorbent layer under the following conditions.

Synthesis gas (B) composition Nitric oxide (NO): 2.7 ppm, nitrogen dioxide (NO
₂ ): 0.3 ppm, sulfur dioxide (SO ₂ ): 0.15 p
pm, H ₂ O: 1.9% by volume, remaining: air treatment conditions Gas amount: 17.3 NL / min, treatment temperature: 25 ° C., space velocity (SV): 30,000 hr ⁻¹ (STP), gas humidity: 60% RH After performing the accelerated durability test for 200 hours, one hour after introducing the synthesis gas (A), nitrogen oxides (NO, NO, NO) in the synthesis gas at the inlet and the outlet of the adsorbent layer.
₂ ) The concentration and the sulfur oxide (SO ₂ ) concentration were measured in the same manner as in the evaluation method (1), and the NO, NO ₂ and SO ₂ removal rates were calculated. Table 2 shows the results of the evaluation test.

[0065]

[Table 2]

Example 19 (Preparation of adsorbent for sulfur oxide) TS obtained in Example 6
-1 Powder was kneaded well with a kneader while adding an appropriate amount of water to 1000 g, and then formed into a pellet having a diameter of 5 mm and a length of 5 mm by an extruder. This pellet is heated at 1100 ° C for 1
After drying for 0 hour, it was baked at 350 ° C. for 3 hours in an air atmosphere. Further, the pellet was impregnated with a 6N-sodium carbonate aqueous solution for 2 minutes, and then dried at 120 ° C. for 5 hours. The composition of the adsorbent for sulfur oxides obtained in this manner has TS-1: Na (as TS-1: Na ₂ O) = 7.
6.1: 23.9 (% by weight).

(Evaluation Method) Evaluation method of Example 18 (1)
Evaluation methods (1) and (2) except that the gas flow was filled with 19 ml of the adsorbent for sulfur oxide in the first stage and 35 ml of the adsorbent (1) obtained in Example 1 in the second stage.
In the same manner as in (2), the nitrogen oxide adsorbing ability and the sulfur oxide adsorbing ability were evaluated. Table 3 shows the results.

From the results in Tables 2 and 3, it can be seen that the durability of the adsorbent (2) is improved by installing the adsorbent for sulfur oxide in the preceding stage.

Examples 20 to 21 In the evaluation method of Example 19, the adsorbents (10) and (1) obtained in Examples 10 and 13 were used as subsequent adsorbents.
The nitrogen oxide adsorbing ability and the sulfur oxide adsorbing ability were evaluated in the same manner as in Example 19 except that 3) was used. Table 3 shows the results.

From the results in Tables 2 and 3, it can be seen that the durability performance of the adsorbents (10) and (13) is improved by installing the adsorbent for sulfur oxide in the preceding stage.

[0071]

[Table 3]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 53/60 B01D 53/34 132Z 53/74 B01J 20/30 (72) Inventor Hironobu Ono Himeji, Hyogo Prefecture 992, Nishioki, Okihama-shi, Abashiri-ku, Japan F-term (reference) 4D002 AA02 AA12 AC01 BA04 CA07 DA01 DA08 DA11 DA14 DA21 DA22 DA24 DA25 DA46 EA06 GA01 GA02 GB01 GB02 GB03 GB08 GB12 4G066 AA06D AA10D AA22A AA28B AA43A AA47A BA36 CA23 CA28 DA02 DA03 FA05 FA14 FA18 FA21 FA25

Claims (7)

[Claims] An adsorbent for a nitrogen oxide and / or a sulfur oxide containing an alkali metal element, wherein the adsorbent has been heat-treated in the presence of a reducing agent. Sulfur oxide adsorbent. 2. The adsorbent for a nitrogen oxide and / or a sulfur oxide containing an alkali metal element is at least one selected from (1) an alkali metal element and (2) manganese, nickel, cobalt, iron and lead. 2. The adsorbent according to claim 1, which is an adsorbent containing the following elements: 3. The adsorbent for a nitrogen oxide and / or a sulfur oxide containing an alkali metal element is at least one selected from (1) an alkali metal element and (2) manganese, nickel, cobalt, iron and lead. 2. The adsorbent according to claim 1, wherein the adsorbent contains an element of the formula (1) and (3) at least one element selected from the group consisting of titanium, silicon, aluminum, zirconium and alkaline earth metal elements. 4. An adsorbent for a nitrogen oxide and / or a sulfur oxide containing an alkali metal element is at least one selected from (1) an alkali metal element and (2) manganese, nickel, cobalt, iron and lead. And (3) at least one element selected from titanium, silicon, aluminum, zirconium and alkaline earth metal elements and (4) at least one element selected from platinum, gold, ruthenium, rhodium and palladium The adsorbent according to claim 1, which is a contained adsorbent. 5. The adsorbent according to claim 1, wherein the reducing agent is hydrogen. 6. A method comprising contacting a gas containing nitrogen oxides and / or sulfur oxides with the adsorbent according to claim 1 to adsorb and remove nitrogen oxides and / or sulfur oxides. A method for removing nitrogen oxides and / or sulfur oxides, which is a feature. 7. A method for removing a nitrogen oxide by adsorbing a gas containing a nitrogen oxide and a sulfur oxide by removing the sulfur oxide from the gas and then bringing the gas into contact with a nitrogen oxide adsorbent. A method for removing nitrogen oxides and sulfur oxides, comprising using the adsorbent according to claim 1 as an adsorbent for oxides.