KR102558233B1 - Acid exhaust gas treatment agent, acid exhaust gas treatment method, and acid exhaust gas treatment facility - Google Patents

Abstract

The present invention provides an acidic exhaust gas treatment agent, an acidic exhaust gas treatment method, and an acidic exhaust gas treatment facility capable of increasing nitrogen monoxide removal efficiency compared to the prior art in treating acidic exhaust gas generated in combustion facilities such as thermal power plants and incineration facilities using layered double oxide. An acidic exhaust gas treatment method of the present invention is made by using an acidic exhaust gas treatment agent comprising a composite of Mg-Al-based layered double hydroxide and at least one of manganese oxide and a permanganic acid compound, comprising: contacting the acidic exhaust gas with the acidic exhaust gas treatment agent to adsorb acidic substances in the acidic exhaust gas; and a step (3) of recovering the acidic substance desorbed from the acidic exhaust gas treatment agent in the step (2).

Description

Acid exhaust gas treatment agent, acid exhaust gas treatment method, and acid exhaust gas treatment facility

The present invention relates to an acid exhaust gas treatment agent, an acid exhaust gas treatment method, and an acid exhaust gas treatment facility applied to treatment of acid exhaust gas generated from combustion facilities such as thermal power plants and incineration facilities.

BACKGROUND OF THE INVENTION Combustion exhaust gas generated in thermal power generation or waste incineration contains harmful acidic substances such as hydrogen chloride, sulfur oxides and nitrogen oxides. For this reason, the acidic exhaust gas containing the said acidic substance is being treated by various methods for removing the said acidic substance.

For hydrogen chloride and sulfur oxides among the above acidic substances, a dry method in which an alkali agent such as slaked lime is used to neutralize the product and the product is collected with a dust collector, or a wet method in which a scrubber is used for neutralization treatment are popular.

For nitrogen oxides, a selective catalytic reduction method (SCR) in which a reducing agent such as ammonia or urea is mixed with combustion exhaust gas and then vanadium or platinum is decomposed into nitrogen and water by a catalyst supported on a support such as ceramic, or a non-catalytic reduction method (SNCR) in which nitrogen oxide is decomposed by directly spraying a reducing agent such as ammonia or urea into an incinerator or the like is widespread.

However, the treatment by the above neutralization treatment requires a treatment step of the neutralized product, and also requires a separate treatment of nitrogen oxides.

In addition, in the treatment of nitrogen oxides by SCR or SNCR, there is a problem of requiring the use of a reducing agent, a catalyst, and the like, and the cost of facilities and energy for the same.

In response to these problems, the present inventors have proposed a method capable of treating the acidic exhaust gas efficiently and at a lower cost by using a carbonate-type Mg-Al-based layered double oxide (see Patent Document 1).

Patent Document 1: Japanese Unexamined Patent Publication No. 2016-190199

However, even with the treatment method described in Patent Literature 1, there have been cases where nitrogen monoxide removal treatment is not necessarily sufficient.

Therefore, in the treatment of acidic exhaust gas using layered double oxide, improvement in the removal efficiency of nitrogen monoxide has been demanded.

The present invention has been made under these circumstances, and an object of the present invention is to provide an acidic exhaust gas treatment agent, an acid exhaust gas treatment method, and an acid exhaust gas treatment facility capable of increasing nitrogen monoxide removal efficiency compared to the prior art in treating acid exhaust gas generated from combustion facilities such as thermal power plants and incineration facilities using layered double oxide.

The present invention has been made based on the discovery that a composite of Mg—Al-based layered double oxide (hereinafter also referred to as Mg—Al LDH (Layered Double Hydroxide)) by manganese oxide or the like has excellent nitrogen monoxide removal performance.

That is, the present invention provides the following [1] to [7].

[1] An acidic exhaust gas treatment agent containing a composite of at least one of manganese oxide and permanganic acid compound of a Mg-Al-based layered double hydroxide.

[2] The acidic exhaust gas treatment agent described in [1] above, wherein the complex is at least one of a manganese dioxide composite Mg-Al-based layered double hydroxide and a permanganate-type Mg-Al-based layered double hydroxide.

[3] The acidic exhaust gas treatment agent described in [1] or [2] above, containing a carbonate-type Mg-Al-based layered double hydroxide.

[4] A method of treating an acidic exhaust gas using the acidic exhaust gas treating agent described in any one of [1] to [3] above, comprising a step (1) of bringing the acidic exhaust gas into contact with the acidic exhaust gas treating agent to adsorb an acidic substance in the acidic exhaust gas; An acidic exhaust gas treatment method comprising a step (3) of recovering a substance.

[5] The acidic exhaust gas treatment method described in [4] above, in which the treatment cycle including the steps (1) to (3) is repeatedly performed, and in the step (1) of at least one treatment cycle after the second treatment cycle, the acidic exhaust gas treatment agent regenerated in the step (2) of at least one treatment cycle prior to the treatment cycle is used as at least a part of the acidic exhaust gas treatment agent.

[6] A facility for treating acidic exhaust gas using the acidic exhaust gas treating agent described in any one of [1] to [3], comprising means (1) for contacting the acidic exhaust gas with the acidic exhaust gas treating agent to adsorb acidic substances in the acidic exhaust gas, means (2) for regenerating the acidic exhaust gas treating agent by desorbing acidic substances adsorbed to the acidic exhaust gas treating agent in the means (1), and acid desorbed from the acidic exhaust gas treating agent in the means (2). An acid exhaust gas treatment facility having means (3) for recovering substances.

[7] The acidic exhaust gas treatment method described in [4] above, by a manufacturing method that does not require a reduction step, wherein the manganese dioxide composite Mg-Al-based layered double hydroxide is produced by adding Mg-Al oxide to an aqueous solution of potassium permanganate, filtering and drying the precipitate.

By using the acidic exhaust gas treatment agent of the present invention, acidic exhaust gases such as hydrogen chloride, sulfur oxides and nitrogen oxides generated in combustion facilities such as thermal power plants and incineration facilities can be simultaneously removed and treated, and in particular, the removal efficiency of nitrogen monoxide is improved compared to the case of using conventional layered double hydroxide.

Further, according to the acid exhaust gas treatment method of the present invention using the acid exhaust gas treatment agent, the acid exhaust gas can be efficiently removed with a smaller amount of the treatment agent than before, and furthermore, the acid exhaust gas treatment agent can be recycled.

Further, according to the acid exhaust gas treatment facility of the present invention, the above acid exhaust gas treatment method can be suitably carried out, and it becomes possible to treat the acid exhaust gas more efficiently and at a lower cost than before.

Fig. 1 is a graph showing the change over time of the _NOx concentration of the outlet gas of the reaction tube in the acid exhaust gas treatment performance evaluation test of Example.
Fig. 2 is a powder X-ray diffraction diagram of the product of Synthesis Example 1.
Fig. 3 is a powder X-ray diffraction diagram of the product of Synthesis Example 2.
4 is a powder X-ray diffraction diagram of CO ₃ type Mg—Al LDH.
5 is an XPS spectrum of the product of Synthesis Example 1.
6 is an XPS spectrum of the product of Synthesis Example 2.

Hereinafter, the acid exhaust gas treatment agent of the present invention, an acid exhaust gas treatment method using the same, and an acid exhaust gas treatment facility are described in detail.

[Acid Exhaust Gas Treatment Agent]

The acidic exhaust gas treatment agent of the present invention contains a complex of Mg-Al LDH with at least one of manganese oxide and permanganic acid compound (hereinafter also referred to as a Mn-O compound).

Thus, by using Mg—Al LDH as a composite of manganese and oxygen (Mn—O compound) as an acidic exhaust gas treatment agent, the removal efficiency of nitrogen monoxide can be improved compared to the case of using Mg—Al LDH, which is a conventional layered double oxide, or the like.

This is presumed to be because, although Mg-Al LDH itself is difficult to adsorb nitrogen monoxide, nitrogen monoxide is easily oxidized to nitrogen dioxide and then oxidized to nitrate ions by the catalytic action of the complexed Mn-O compound, so that it is easily adsorbed onto the composite of Mg-Al LDH.

Manganese can have an oxidation number of +2 to +7, but from the viewpoint of the action as an oxidation catalyst, a higher oxidation number is preferable. As the composite, from the viewpoint of ease of synthesis, for example, a manganese dioxide composite Mg-Al layered double hydroxide of manganese having an oxidation number of +4 (hereinafter also referred to as MnO ₂ complex Mg-Al LDH) or a permanganate type Mg-Al layered double hydroxide of manganese having an oxidation number of +7 (hereinafter also referred to as MnO ₄ type Mg-Al LDH) is preferable. The composite material may be used singly or may contain two or more kinds.

The structural formula of MnO ₂ complex Mg-Al LDH is shown in formula (1) below, and the structural formula of MnO ₄ type Mg-Al LDH is shown in formula (2) below.

In the above formulas (1) and (2), usually x = 0.20 to 0.40 and m = 1 to 12.

The acidic exhaust gas treatment agent preferably contains carbonic acid type Mg-Al layered double hydroxide (hereinafter also referred to as CO ₃ type Mg-Al LDH).

As described in Patent Document 1, CO ₃ -type Mg-Al LDH is a compound that can be suitably used for treating acidic exhaust gas, and can efficiently remove acidic compounds other than nitrogen monoxide, such as hydrogen chloride, sulfur dioxide, and nitrogen dioxide, contained in acidic exhaust gas. For this reason, it is preferable to use it together with the said composite material.

In this case, the ratio of the content of the composite material and CO ₃ type Mg-Al LDH in the acid exhaust gas treatment agent is not particularly limited, and is appropriately set depending on the component composition of the acid exhaust gas, such as the amount of nitrogen monoxide contained in the acid exhaust gas to be treated.

CO ₃ -type Mg-Al LDH is a hydrotalcite, and naturally occurring clay minerals also exist. However, the synthesis method in the case of synthesis is not particularly limited, and a known method (for example, the method described in Patent Document 1) can be used.

For example, it can be obtained by adding dropwise an aqueous solution of magnesium nitrate (Mg(NO ₃ ) ₂ ) and aluminum nitrate (Al(NO ₃ ) ₃ ) to an aqueous solution of sodium carbonate (Na ₂ CO ₃ ) while maintaining the pH at 10.5. Specifically, it can be synthesized by the method shown in the Examples below.

In addition, in the case of MnO ₂ complex Mg-Al LDH and MnO ₄ type Mg-Al LDH, the synthesis method is not particularly limited, but it can be synthesized by using CO ₃ type Mg-Al LDH as a raw material compound and using an anion exchange function by intercalation thereof.

For example, MnO ₄ -type Mg-Al LDH containing permanganate ion (MnO ₄ ^- ) can be synthesized by calcining CO ₃ -type Mg-Al LDH at 500 °C to obtain Mg-Al oxide, and then adding it to an aqueous solution of potassium permanganate (KMnO ₄ ) and mixing.

In addition, the MnO ₄ -type Mg-Al LDH changes to the MnO ₂ complex Mg-Al LDH in an aqueous solution of potassium permanganate (KMnO ₄ ).

In addition, the MnO ₄ -type Mg—Al LDH can be added to a manganese chloride (MnCl ₂ ) aqueous solution and mixed to synthesize a MnO ₂ composite Mg—Al LDH.

The acidic exhaust gas treatment agent may contain agents other than layered double hydroxides such as calcium hydroxide (slaked lime), calcium oxide, sodium bicarbonate (sodium bicarbonate), sodium carbonate, dolomite hydroxide, light dolomite, aluminum hydroxide, aluminum oxide, magnesium hydroxide, magnesium oxide, etc., within a range that does not impair the effect of the present invention. However, in the acid exhaust gas treatment method described later, when the acid exhaust gas treatment agent is recycled and used for reuse, it is preferable that these chemicals are not contained from the viewpoint of purity of the regenerated product or recovery operation.

[Acid Exhaust Gas Treatment Method]

A method of treating acidic exhaust gas using the acid exhaust gas treatment agent is not particularly limited, but the acid exhaust gas treatment agent (hereinafter also simply referred to as a treatment agent) is preferably applied to the acid exhaust gas treatment method of the present invention.

The acidic exhaust gas treatment method of the present invention is a treatment method comprising: a step (1) of bringing acidic exhaust gas into contact with the treatment agent to adsorb an acidic substance in the acidic exhaust gas; a step (2) of regenerating the treatment agent by desorbing the acidic substance adsorbed to the treatment agent in the step (1);

According to the above treatment method, the recycled treatment agent can be reused. In addition, an acidic substance is recovered as an acid (aqueous solution) by dissolving it in water, for example, and this acid can also be used for industrial purposes and the like.

In the step (1), nitrogen monoxide is oxidized by the complex in the treatment agent, and the acidic substance is adsorbed to the treatment agent by anion exchange or the like involving acidic substances in acidic exhaust gas between layers of the layered double hydroxide.

Next, in the step (2), the acidic substance adsorbed to the treatment agent is desorbed from the treatment agent by reversible anion exchange or the like. Anion exchange in this case can be carried out by mixing and stirring various aqueous solutions in the same way as the synthesis method of, for example, CO ₃ -type Mg-Al LDH, MnO ₂ complex Mg-Al LDH, and MnO ₄ -type Mg-Al LDH, whereby the treatment agent can be easily regenerated.

Since the processing agent thus regenerated can be reused, the processing cost of the acid exhaust gas can be reduced.

In the said process (3), the acidic substance desorbed from the said processing agent in the said process (2) is collect|recovered. For example, it can be dissolved in water and recovered as an acid (aqueous solution), and the acid can also be used for industrial purposes and the like.

Thus, the treatment method according to the present invention is a method excellent in recyclability not only for the treatment agent but also for acidic exhaust gas to be treated.

In the treatment method, it is preferable to repeat the treatment cycle including the steps (1) to (3), and in the step (1) of at least one treatment cycle after the second treatment cycle, the treatment agent regenerated in the step (2) of at least one treatment cycle prior to the treatment cycle is used for at least a part of the treatment agent.

In this way, when the above treatment method is repeatedly performed, by reusing the treatment agent regenerated in the previous step, the total amount of the treatment agent required for treatment of acidic exhaust gas can be reduced, leading to a reduction in the treatment cost of acidic exhaust gas.

The method for treating acidic exhaust gas of the present invention as described above is excellent in work efficiency because various acidic substances in acidic exhaust gas can be simultaneously removed and treated with one type of treatment agent. In particular, by using the composite material as a treatment agent, the removal efficiency of nitrogen monoxide can be increased more than before.

In addition, neutralization products are not generated during the treatment, and the processing load of waste generated in the treatment can be reduced.

[Acid Exhaust Gas Treatment Facility]

The facility for treating acidic exhaust gas using the acid exhaust gas treatment agent is not particularly limited, but the treatment agent is preferably applied in the acid exhaust gas treatment facility of the present invention.

The acidic exhaust gas treatment facility of the present invention is a treatment facility provided with means (1) for bringing acidic exhaust gas into contact with the treatment agent to adsorb acidic substances in the acidic exhaust gas, means (2) for desorbing the acidic substances adsorbed to the treatment agent in the means (1) and regenerating the treatment agent, and means (3) for recovering the acidic substance desorbed from the treatment agent in the means (2).

The said means 1 can be comprised, for example by providing the passage of acid exhaust gas in the container in which the said processing agent was accommodated.

The means (2) is, for example, an immersion bath in which the treatment agent taken out of the container after flowing the acidic exhaust gas is immersed in various aqueous solutions according to the chemical species to be complexed with Mg-Al LDH by the same method as the method for synthesizing CO ₃ type Mg-Al LDH, MnO ₂ complex Mg-Al LDH and MnO ₄ type Mg-Al LDH, and mixing and stirring.槽) can be configured.

The means 3 can be configured as, for example, an aqueous solution accommodating tank that is dissolved in water and recovered as an acid (aqueous solution).

The acid exhaust gas treatment facility can be attached to a combustion facility for thermal power generation or waste incineration. For example, in the case of treating acidic exhaust gas generated in a waste incinerator, the acid exhaust gas treatment facility is installed following the boiler, exhaust gas cooling device, and dust collector sequentially installed in the combustion exhaust gas system of the incinerator main body, and the exhaust gas treated by the acid exhaust gas treatment facility is guided to a chimney by an induced ventilator or the like, and discharged from the chimney to the atmosphere.

(Example)

The present invention will be described in more detail below, but the present invention is not limited by the following examples.

[Synthesis Example 1] Synthesis of MnO ₂ complex Mg-Al LDH

Using magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, a mixed aqueous solution (magnesium/aluminum = 2/1 (molar ratio)) having a magnesium concentration of 0.33 mol/L and an aluminum concentration of 0.17 mol/L was prepared.

This mixed solution was added dropwise to an aqueous sodium carbonate solution having a concentration of 0.1 mol/L at 30°C while stirring. At this time, the pH was maintained at 10.5 by adding dropwise an aqueous solution of sodium hydroxide having a concentration of 1.25 mol/L.

After completion|finish of dripping, it stirred at 30 degreeC for 1 hour. Thereafter, the precipitate was filtered, washed repeatedly, and dried under reduced pressure at 40°C for 40 hours to obtain CO ₃ type Mg-Al LDH.

After calcining the obtained CO ₃ -type Mg-Al LDH at 500°C for 2 hours, it was added to a 0.2 mol/L aqueous solution of potassium permanganate under a stream of nitrogen gas and stirred at 30°C for 6 hours. Thereafter, the precipitate was filtered, washed repeatedly, and dried under reduced pressure at 40°C for 40 hours. The resulting product was added to a 0.1 mol/L aqueous solution of manganese chloride under a stream of nitrogen gas and stirred at 30°C for 3 hours. Thereafter, the precipitate was filtered, washed repeatedly, and dried under reduced pressure at 40°C to obtain MnO ₂ complex Mg—Al LDH (Mg _0.62 Al _0.38 (OH) ₂ (MnO ₂ ) _0.95 (Cl) _0.38 1.13H ₂ O).

[Synthesis Example 2] Synthesis of MnO ₂ Complex Mg-Al LDH

Using magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, a mixed aqueous solution (magnesium/aluminum = 2/1 (molar ratio)) having a magnesium concentration of 0.33 mol/L and an aluminum concentration of 0.17 mol/L was prepared.

This mixed solution was added dropwise to an aqueous sodium carbonate solution having a concentration of 0.1 mol/L at 30°C while stirring. At this time, the pH was maintained at 10.5 by adding dropwise an aqueous solution of sodium hydroxide having a concentration of 1.25 mol/L.

After completion|finish of dripping, it stirred at 30 degreeC for 1 hour. Thereafter, the precipitate was filtered, washed repeatedly, and dried under reduced pressure at 40°C for 40 hours to obtain CO ₃ type Mg-Al LDH.

After calcining the obtained CO ₃ -type Mg-Al LDH at 500°C for 2 hours, it was added to a 0.2 mol/L aqueous solution of potassium permanganate under a stream of nitrogen gas and stirred at 30°C for 6 hours. Thereafter, the precipitate was filtered, washed repeatedly, and dried under reduced pressure at 40°C for 40 hours.

Further, CO ₃ type Mg-Al LDH, MnO ₄ type Mg-Al LDH, and MnO ₂ complex Mg-Al LDH in Synthesis Example 1 and Synthesis Example 2 were phase identified by powder X-ray diffraction measurement (powder XRD). For the CO ₃ type Mg-Al LDH, a powder X-ray diffraction diagram is shown in FIG. 4 . The X-ray diffraction measuring device used was "RINT-2200VHF" manufactured by Rigaku Corporation, and measurement was performed using CuKα rays (1.5418 A) as characteristic X-rays. In addition, for the composite material by the Mn-O compound, elemental analysis values by inductively coupled plasma emission spectroscopy (ICP-AES) are also shown. In Synthesis Example 1 and Synthesis Example 2, MnO ₄ type Mg-Al LDH and MnO ₂ complex Mg-Al LDH were identified by specifying the oxidation number of Mn using X-ray photoelectron spectroscopy (XPS).

[Acid exhaust gas treatment performance evaluation test]

(Example 1)

1.0 g of MnO ₂ composite Mg—Al LDH obtained in Synthesis Example 1 was charged onto glass wool in a reaction tube (inner diameter: 16 mm) of a tubular electric furnace. The set temperature of the tubular electric furnace was set at 170°C, and a test gas (carrier gas: nitrogen, nitrogen monoxide gas concentration: 150 volppm, oxygen gas concentration: 10 vol%) was flowed through the reaction tube at a linear speed of 1.0 m/min while adjusting the flow rate with a mass flow controller. The change in _NOx concentration with time (90 minutes) in the outlet gas of the reaction tube was measured with a combustion exhaust gas analyzer (product of Testo KK) by a potentiostatic electrolysis method.

(Comparative Example 1)

An evaluation test was conducted in the same manner as in Example 1 except that the MnO ₂ complex Mg-Al LDH in Example 1 was replaced with the CO ₃ type Mg-Al LDH obtained in the synthesis process of Synthesis Example 1.

Fig. 1 graphically shows the change in the _NOx concentration of the outlet gas of the reaction tube in Example 1 and Comparative Example 1 over time.

Further, as a result of determining the reaction rate of nitrogen monoxide gas in the test gas from the integrated concentration of _NOx concentration, it was 91.5 vol% in Example 1 and 2.2 vol% in Comparative Example 1.

From these results, it was confirmed that the composite of manganese dioxide and Mg—Al-based layered double hydroxide had better nitrogen monoxide removal performance than CO ₃ -type Mg—Al LDH.

[Analysis of abundance ratio of MnO ₂ complex Mg-Al LDH according to Synthesis Example 1 and Synthesis Example 2]

2 and 3 show powder X-ray diffraction diagrams of products according to Synthesis Example 1 and Synthesis Example 2. 5 and 6 show XPS spectra of the products according to Synthesis Example 1 and Synthesis Example 2.

From the element analysis values, the Mg/Al molar ratios of the products of Synthesis Example 1 and Synthesis Example 2 were 1.9 and 1.6, respectively, which almost coincided with the initial Mg/Al molar ratio of 2.0.

According to the powder X-ray diffraction diagrams of FIGS. 2 and 3, both showed X-ray peaks attributed to LDH, and the LDH structure was confirmed in both products with interplanar spacing (d ₀₀₃ ) of 7.6 Å and 7.5 Å.

From the XPS spectra of FIGS. 5 and 6, it was confirmed that the peak of Mn(IV) derived from MnO ₂ was confirmed, and from the peak area, it was confirmed that all Mn(IV) was present at 95% or more of the total amount of Mn.

From these results, as in Synthesis Example 2, it was confirmed that the MnO ₂ composite Mg—Al LDH could be synthesized even without the reduction step of introducing the manganese chloride aqueous solution shown in Synthesis Example 1.

In Synthesis Example 2, the MnO ₂ composite Mg-Al LDH was determined to be produced as follows.

First, CO ₃ type Mg-Al LDH is calcined at 500°C for 2 hours, then the _resulting Mg-Al oxide (Mg _{1-x Al x} O _1+x/2 ) is added to a 0.2 mol/L potassium permanganate aqueous solution under a nitrogen gas stream, and stirred at ₃₀ ° C. for 6 hours. OH) ₂ (MnO ₄ ) _x ) is produced.

In addition, the reaction shown in formula (4) occurs in an aqueous solution of potassium permanganate, and MnO ₂ type Mg-Al LDH (Mg _1-x Al _x (OH) ₂ (MnO ₂ ) _x ) is generated.

Claims (7)

An acidic exhaust gas treatment agent containing at least any one composite of a compound represented by the following general formula (1) and a compound represented by the following general formula (2).

In the above formulas (1) and (2), x = 0.20 to 0.40 and m = 1 to 12.
According to claim 1,
An acidic exhaust gas treatment agent comprising a carbonate-type Mg-Al-based layered double hydroxide.
A method of treating acid exhaust gas using the acid exhaust gas treatment agent of claim 1 or 2,
Step (1) of bringing the acidic exhaust gas into contact with the acidic exhaust gas treatment agent to adsorb acidic substances in the acidic exhaust gas;
Step (2) of regenerating the acidic exhaust gas treatment agent by desorbing the acidic substance adsorbed to the acid exhaust gas treatment agent in the step (1);
Step (3) of recovering the acidic substance desorbed from the acidic exhaust gas treatment agent in the step (2)
Acid exhaust gas treatment method comprising.
According to claim 3,
The treatment cycle including the steps (1) to (3) is repeatedly performed, and in the step (1) of at least one treatment cycle after the second treatment cycle, the acidic exhaust gas treatment agent is used as at least a part of the acidic exhaust gas treatment agent regenerated in the step (2) of at least one treatment cycle prior to the treatment cycle.
A facility for treating acid exhaust gas using the acid exhaust gas treatment agent according to claim 1 or 2,
means (1) for adsorbing an acidic substance in the acidic exhaust gas by bringing the acidic exhaust gas into contact with the acidic exhaust gas treatment agent;
means (2) for regenerating the acidic exhaust gas treatment agent by desorbing the acidic substance adsorbed to the acid exhaust gas treatment agent in the means (1);
An apparatus for implementing the means (3) for recovering the acidic substance desorbed from the acidic exhaust gas treatment agent in the means (2).
Acid exhaust gas treatment facility provided.
According to claim 3,
The manganese dioxide composite Mg-Al-based layered double hydroxide of the general formula (1) is produced by adding Mg-Al oxide to an aqueous solution of potassium permanganate, filtering and drying the precipitate, Acidic exhaust gas treatment method by a manufacturing method that does not require a reduction step.
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