JP5487483B2 - Adsorbent - Google Patents

Description

  The present invention relates to a porous aluminosilicate-carbon composite that can be used as an adsorbent that simultaneously adsorbs carbon dioxide and water vapor, and a method for producing the same.

  When humans act in a closed space in the universe, if they breathe, carbon dioxide gas and water are discharged from the human body, and trace harmful substances such as carbon monoxide and aldehydes are discharged, which needs to be removed. . Conventionally, for example, techniques disclosed in Non-Patent Documents 1 to 6 have been proposed as techniques for adsorbing and removing carbon dioxide gas or water discharged from a human body.

  Non-Patent Document 1 discloses an adsorption device using zeolite as an adsorbent. Carbon dioxide and water are discharged in large quantities when humans are active. In order to remove this, in Non-Patent Document 1, zeolite is arranged in two stages. In this apparatus, moisture is removed from the first-stage zeolite, and carbon dioxide gas in the dry gas is adsorbed and removed from the second-stage zeolite. Accordingly, when water and carbon dioxide coexist, carbon dioxide is not adsorbed.

  Non-Patent Document 2 discloses a type of adsorption device that uses lithium hydroxide as an adsorbent and does not regenerate the adsorbent. As another method, a method using four molecular sieve chambers is also disclosed. In this method, two molecular sieve chambers are arranged in parallel, and moisture in the air is adsorbed and removed in the upstream molecular sieve chamber of one row, and then carbon dioxide gas is adsorbed and removed in the downstream molecular sieve chamber. The adsorbed carbon dioxide gas is recovered by raising the temperature or evacuating the room, and hydrogenating the carbon dioxide gas by a Sabatier reaction to convert it into methane and water is adopted.

  In Non-Patent Document 3, two adsorption beds composed of a silica gel layer, a molecular sieve 13X layer, and a zeolite 5A layer are arranged in parallel from the gas inlet to the gas outlet, while carbon dioxide gas and water are supplied. An apparatus is disclosed that, when adsorbed and removed, when its adsorbing capacity is reduced, switches the flow path to the other bed and continues adsorbing and removing carbon dioxide and water. In this apparatus, the flow path is switched to the other bed, and at the same time, the one bed whose adsorption capacity is reduced is evacuated, and the adsorbed carbon dioxide gas and water are removed from the adsorbent and regenerated. The regenerated adsorbent is subjected to the next adsorption cycle. In this adsorption bed, the first silica gel layer adsorbs and removes water, and the molecular sieve 13X layer removes water that is not fully removed, or if the water is completely removed by the silica gel layer, carbon dioxide gas is removed. Adsorb.

  Non-Patent Document 4 discloses an apparatus using an adsorbent in which a solid amine is supported in an aluminum foam. In this device, the adsorbent is regenerated using a vacuum obtained in outer space.

  Non-Patent Document 5 discloses an apparatus having a structure in which an adsorbent such as liquid amine is supported on a honeycomb catalyst made of porous carbon. This device has less pressure loss when passing through the adsorbent layer of the airflow because of the honeycomb structure. The porous carbon honeycomb is prepared by pyrolyzing polyvinylidene chloride.

  In Non-Patent Document 6, dehydration is performed with a molecular sieve 13X, and then the dehydrated gas is passed through a molecular sieve 5A and then passed through an activated carbon adsorbent to adsorb a trace amount of harmful gas, and then carbon monoxide contained in the gas. Has been disclosed that oxidizes the catalyst with a platinum catalyst supported on activated carbon to produce harmless carbon dioxide.

Generally, Ca ²⁺ -A type zeolite is used for adsorption of carbon dioxide gas in the gas. However, as disclosed in Non-Patent Document 7, this type of zeolite has a high water adsorption affinity and adsorbs preferentially to zeolite over carbon dioxide gas.

  Non-Patent Document 8 and Non-Patent Document 9 disclose techniques for producing ZSM-5 zeolite from rice husk. This ZSM-5 zeolite is used as a catalyst such as a desulfurization catalyst in petroleum refining, and is different from the zeolite used as an adsorbent in Non-Patent Document 1 and the like.

“International Space Station Carbon Dioxide Removal Assembly (ISS CDRA) Concept and Advantages”, Dina EI Sherif and James C. Knox, ICES 2005-01-2892 “Evolution of Life Support from Apollo, Shuttle, and ISS to the Vision for the Moon and Mars” Harry Jones, ICES 2006-01-2013 “Mathematical Simulation of the Sorbent-Based Atmosphere Revitalization System for the Crew Exploration Vehicle”, Steven P. Reynols, Armin D. Ebner and James A. Ritter, James C. Knox and M. Douglas LeVan, ICES 2006-01-2220 “Development Status of Amine-based, Combined Humidity, CO2 and Trace Contaminant Control System for CEV” Tim Nalette, William Papale, Fred Smith and Jay Perry, ICES 2006-01-2192 Marek A. Wojtowicz, Elizabeth Florczak, Erik Kroo, Eric P. Rubenstein, Michael A. Serio and Tom Filburn, ICES 2006-01-2193 Robert J. Kay and Allen K. MacKnight, ICES 2006-01-2196 Edited by Hiroo Tominaga, “Science and Application of Zeolite”, Kodansha Scientific, 1996, p. 166 R.K.Vempati et al., Micrororous and Mesoporous Materials, 93 (2006), 134-140 H. Katsuki et al., Micrororous and Mesoporous Materials, 86 (2005), 145-151 N.K.Sharma, Wendell S. Williams and A. Zangvil, “Formation and Structure of Silicon Carbide Wiskers from Rice Hulls”, J. Am. Ceram. Soc., 67, No11, 715-720 (1984)

However, the above-described prior art has the following problems.
When molecular sieve or zeolite is used, if water and carbon dioxide coexist in the gas to be treated, water preferentially occupies the adsorption point and carbon dioxide is not adsorbed. Therefore, it is necessary to first remove water and then adsorb carbon dioxide in a dry state without water. The adsorption system requires a two-stage adsorption layer, which complicates the apparatus and increases the volume and mass. Therefore, adopting this method in outer space is disadvantageous for transporting and operating the device into outer space.
Further, in the adsorption removal of carbon dioxide gas using amine, there is a concern about the corrosion of the adsorbent and generation of harmful substances from the amine.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an adsorbent capable of simultaneously adsorbing and removing carbon dioxide gas, water and a trace amount of harmful gas.

In order to achieve the above object, the present invention comprises a step of heating a silicate plant to 400 ° C. or higher in an inert atmosphere and baking to produce a carbide, and then examining the silicon content in the obtained carbide. : Al: Na = 1: 0.8 to 1.2: 2.5 to 4.0 (molar ratio) so that an aluminosilicate is generated, an Al compound and an alkali metal compound or an alkaline earth metal A step of preparing a mixture by adding a compound and water, and then a step of hydrothermal reaction of the resulting mixture to obtain a porous aluminosilicate-carbon composite, the porous aluminosilicate Provided is an adsorbent comprising a porous aluminosilicate-carbon composite obtained by a production method in which the salt is an A-type zeolite, wherein at least carbon dioxide gas and moisture in the gas to be treated are simultaneously adsorbed and removed. To do.

In the adsorbent of the present invention, the production method further comprises a step of obtaining a composite having a large surface area by subjecting the obtained porous aluminosilicate-carbon composite to water vapor activation treatment or carbon dioxide activation treatment. It may be.

In the adsorbent of the present invention, the silicate plant is preferably rice husk or straw.

In the adsorbent of the present invention, the Al compound is aluminum hydroxide, and the alkali metal compound or alkaline earth metal compound is one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide. Is preferred.

The adsorbent of the present invention may be formed into a pellet shape or a honeycomb structure.

The porous aluminosilicate-carbon composite of the present invention can adsorb and remove carbon dioxide, water, and a trace amount of harmful gas in the gas to be treated with a single adsorbent.
This makes it possible to use the adsorbent of the present invention for the treatment of exhaled gas in a closed space such as a space station or a space shuttle, and as an adsorbent to keep human activities safely in such special environments. Useful.
Since the adsorbent of the present invention can adsorb and remove carbon dioxide, water, and trace amounts of harmful gases in the gas to be treated with a single adsorbent, the adsorbent can be made smaller than a conventional removal device configured by combining multiple adsorbents. Therefore, the launch cost to outer space can be reduced.
In the adsorbent of the present invention, since water and carbon dioxide gas are removed by adsorption, the adsorbent can be regenerated by vacuum or temperature control, and the reclaimed water can be reused.
The adsorbent of the present invention is useful not only in outer space but also for maintaining safety of human activities such as in a closed space such as a submarine.

The graph which shows the relationship between the specific surface area of rice husk carbide | carbonized_material, baking temperature, and the specific surface area of each adsorbent produced in Example 1 which uses the rice husk carbide obtained at each baking temperature as a raw material, and the baking temperature of the rice husk carbide | carbonized_material of a raw material It is.

  The method for producing a porous aluminosilicate-carbon composite (hereinafter referred to as an adsorbent) of the present invention is a process in which a silicate plant is heated to 400 ° C. or higher in an inert atmosphere and baked to produce a carbide. Then, the silicon content in the obtained carbide is examined, and an Al compound and an alkali metal compound are formed so that an aluminosilicate in the range of Si: Al = 1: 0.1 to 1.2 (molar ratio) is formed. Alternatively, the method includes a step of preparing a mixture by adding an alkaline earth metal compound and water, and then a step of hydrothermal reaction of the obtained mixture to obtain a porous aluminosilicate-carbon composite.

  Examples of the silicic acid plant used as a raw material in the production method of the present invention include gramineous plants such as rice, wheat, barley, rye, pearl barley, millet, millet, millet, corn, and Susuki, among which silicic acid content. Rice husks, rice husks, and the like of rice having a high value are preferred, and rice husks are particularly preferred. Hereinafter, as an embodiment of the production method of the present invention, a case where an adsorbent is produced using rice husk as a raw material will be described.

The rice husk is composed of about 20% by mass of inorganic substance and about 80% by mass of organic substance such as cellulose. Of the inorganic component showing about 20% by mass, 85-95% by mass is active silica (SiO ₂ ). Silica is deposited in the cuticle part when water-soluble silicate ions in irrigation water pass through the roots of rice, pass through stem conduits, and evaporate water from the husk epidermis. Since rice husk silica is deposited between the cell walls, when the rice husk is heated in an inert gas such as nitrogen or argon gas and carbonized organic matter such as cellulose, it is a complex in which silica and carbon are in close proximity. Some rice husk carbide (called rice husk husk charcoal etc.) is obtained.

  The silica and carbon content of the rice husk carbide is very fine, is homogeneous at the molecular level, and has a small distance from each other as compared to a simple silica-carbon mixture. In addition, as a result of analyzing rice husks by ESCA, it was reported that carbon bonds in Si-organic substances, which were thought not to exist in nature, may exist in nature from the measured value of Si-C binding energy. (See Non-Patent Document 10).

  The rice husks may be used after removing foreign substances such as stones and earth by wind selection or sieving as necessary, or leaching with dilute hydrochloric acid, which is contained in trace amounts in inorganic materials, iron, alkali metals A compound or alkaline earth metal compound eluted and removed may be used.

(Baked rice husk)
The rice husk is baked in an inert gas stream such as argon or nitrogen gas at a temperature of 400 ° C. or higher for several minutes to several tens of hours, preferably tens of minutes to several hours to carbonize organic matter in the rice husk, And This firing temperature is 400 ° C. or higher, preferably in the range of 500 to 1000 ° C. If the firing temperature is less than 400 ° C., carbonization of rice husks becomes insufficient, and it takes a long time to complete carbonization, which is not preferable.

(Hydrothermal reaction)
The rice husk carbide obtained by the firing is examined for silicon content in the carbide using atomic absorption spectrometry or the like. As described above, since most of the inorganic substance in the rice husk is silica, usually only the silicon content needs to be measured. The content of Ca or the like may be measured and used for the next preparation.

  Then, based on the silica content contained in the rice husk carbide, an Al compound and an alkali metal compound so that an aluminosilicate in the range of Si: Al = 1: 0.1 to 1.2 (molar ratio) is formed. Alternatively, an alkaline earth metal compound and water are added to prepare a mixture. As the Al compound used here, aluminum hydroxide is preferable. The alkali metal compound or alkaline earth metal compound is preferably one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide.

In the production method of the present invention, the porous aluminosilicate formed in the adsorbent is preferably a zeolite, and among them, an A-type zeolite, an X-type zeolite, and a Y-type zeolite are preferable, and further obtained. Since the adsorbent has high adsorbability for water and carbon dioxide, it is particularly preferably A-type zeolite.
In order to obtain A-type zeolite, it is desirable to adjust the components in the range of Si: Al: Na = 1: 0.8 to 1.2: 2.5 to 4.0 (molar ratio).
In order to obtain X-type zeolite, it is desirable to adjust the components in the range of Si: Al: Na = 1: 0.2 to 0.3: 3.5 to 5.0 (molar ratio).
In order to obtain Y-type zeolite, it is desirable to adjust the components in the range of Si: Al: Na = 1: 0.1 to 0.3: 0.8 to 1.0 (molar ratio).

  As described above, a mixture obtained by adding rice husk carbide, Al compound, alkali metal compound or alkaline earth metal compound, and water and mixing them uniformly is then placed in an autoclave at a temperature of 50 to 200 ° C., The hydrothermal reaction is preferably carried out by heating at 80 to 120 ° C. for several minutes to several tens of hours, preferably several tens of minutes to several hours. By this hydrothermal reaction, silica in rice husk carbide reacts with the added Al and Na to produce an aluminosilicate such as zeolite, and a porous aluminosilicate-activated carbon composite together with carbon remaining without reacting. Is obtained.

(Adsorbent)
After this hydrothermal reaction, the treated product is taken out from the autoclave, washed with water, and sufficiently dried to obtain an adsorbent.
This adsorbent can adsorb and remove carbon dioxide, water, and a trace amount of harmful gas in the gas to be treated with a single adsorbent.
This makes it possible to use the adsorbent of the present invention for the treatment of exhaled gas in a closed space such as a space station or a space shuttle, and as an adsorbent to keep human activities safely in such special environments. Useful.
Since the adsorbent of the present invention can adsorb and remove carbon dioxide, water, and trace amounts of harmful gases in the gas to be treated with a single adsorbent, the adsorbent can be made smaller than a conventional removal device configured by combining multiple adsorbents. Therefore, the launch cost to outer space can be reduced.
In the adsorbent of the present invention, since water and carbon dioxide gas are removed by adsorption, the adsorbent can be regenerated by vacuum or temperature control, and the reclaimed water can be reused.
The adsorbent of the present invention is useful not only in outer space but also for maintaining safety of human activities such as in a closed space such as a submarine.

  The adsorbent produced in this way is granular or piece-like based on the shape of the rice husk of the raw material, and can be used as it is filled in a breathable container or the like. Add appropriate binders such as organic adhesives and inorganic adhesives to the granular or flake adsorbents, or granules or powders crushed to an appropriate particle size, and place them in a mold to cure the binders. By doing so, it is also possible to manufacture adsorbents molded into various desired shapes such as a porous columnar shape, a block shape, a cylindrical shape, a honeycomb shape, and a plate shape.

  In this adsorbent, carbon contributes more to the surface area of aluminosilicate and carbon. The surface area can be increased by activating the adsorbent with water vapor or carbon dioxide. By this activation, it is possible to improve the performance of the porous aluminosilicate-activated carbon composite.

(A) Calcination About 20 g of rice husk was heated in a nitrogen stream (100 mL / min) at a heating rate of 5 K / min and a constant temperature (500 to 1000 ° C.) for 1 hour, and then spontaneously cooled to perform calcination. Holding temperature was taken in increments of 100 ° C., and six types of rice husk carbide (hereinafter, rice husk carbide was referred to as PRH) were produced.

(B) Hydrothermal synthesis Next, the content of SiO ₂ and H ₂ O in PRH is measured, and NaOH, Al (OH) is produced so that A-type zeolite, X-type zeolite, and Y-type zeolite are produced after hydrothermal synthesis. _3. H ₂ O was weighed and mixed with PRH. Hereinafter, what is intended to produce A-type zeolite is referred to as Atype, what is intended to produce X-type zeolite is referred to as FAU (X), and what is intended to produce Y-type zeolite is referred to as FAU (Y).
Each preparation of Atype, FAU (X) and FAU (Y) was placed in an autoclave and subjected to hydrothermal treatment. The product was taken out from the autoclave, the solid matter was filtered, washed with distilled water until the filtrate became pH 9 or less, and dried to obtain adsorbents of Type, FAU (X) and FAU (Y).
Table 1 shows the molar ratio of each component used for the preparation of Atype, FAU (X) and FAU (Y) in this example, and hydrothermal reaction conditions.

(C) Analyzer and evaluation device TG-DTA (manufactured by Rigaku Corporation, TG8120) was used as a differential thermogravimetric analyzer. ICP-AES (manufactured by Hitachi, Ltd., P-4010) was used for analysis of trace components in PRH. A scanning electron microscope (manufactured by JEOL Ltd., JSM-5400) was used for crystal structure and microstructure analysis of PRH and each adsorbent. A high-speed specific surface area / pore distribution measuring device (manufactured by Quantachrome, NOVA1200) was used for measurement of the specific surface area and pore distribution. Nitrogen was used as the adsorbate, the BET multipoint method was used for the specific surface area, and the DFT method was used for the pore distribution. The amount of moisture and carbon dioxide adsorbed was measured by weight change using TGA in a gas atmosphere assuming human breath.

<Results and discussion>
(I) Differential Thermogravimetric Analysis In the present invention, since not only silica in rice husk but also organic substances are used, PRH baked in a nitrogen stream is used as a raw material for preparing an adsorbent. From the results of TG-DTA, it can be seen that the decomposition of organic substances in nitrogen is sufficiently completed at 500 ° C., so PRH was baked in increments of 100 ° C. after 500 ° C. to prepare six types.

(Ii) PRH component analysis Table 2 shows the results of PRH component analysis. In Table 2, the number following “PRH” of the sample indicates the firing temperature (that is, “PRH500” means 500 ° C. fired PRH).
As shown in Table 2, approximately half of the PRH was residual carbon and the other half was inorganic. Further, about 95% by mass of the inorganic substance of PRH was SiO ₂ .

(Iii) Specific surface area measurement The result of measuring the specific surface area of each sample of PRH, Atype, FAU (X) and FAU (Y) is shown in FIG.
The reason why the specific surface area of PRH calcined at 500 ° C. is small is considered to be that oily tar coats pores because the calcining temperature is low. The reason why the specific surface area of PRH calcined at 900 ° C. and PRH calcined at 1000 ° C. is small is that potassium content in rice husk reacts with silica to form potassium polysilicate having a low melting point, thereby closing the micropores. It is thought that it was.

(Iv) Crystal structure and microstructure analysis Table 3 shows the X-ray diffraction results of each sample of PRH, Type, FAU (X) and FAU (Y) at each firing temperature. In Table 3, Amorphous, LTA, and FAU indicate the crystal structure of the zeolite in the sample. If Amorphous is not observed (non-crystalline), the LTA indicates the crystal structure of the A-type zeolite. In this case, FAU is when the crystal structure of X-type zeolite or Y-type zeolite is observed.

In PRH, no zeolite crystal structure was observed at all calcination temperatures.
In Atype, the crystal structure of A-type zeolite was observed in all samples.
The reason why no crystal peak was observed in FAU (X) calcined at 1000 ° C. is that the activity of silica is low at PRH with a high calcining temperature and it is difficult to produce zeolite by hydrothermal synthesis. It is done.
In FAU (Y), there is little solution when producing zeolite, the solution is not completely immersed in the sample, and 500 ° C. calcining and 600 ° C. calcining with high residual carbon content are not dissolved in silica. Is considered not to be generated sufficiently. Moreover, in 900 degreeC baking FAU (Y), it is thought that the production | generation of a potassium polysilicate has started and the production | generation of a zeolite is inhibited. On the other hand, in 1000 degreeC baking FAU (Y), it is thought that this inhibition was hard to occur by volatilization of a potassium content.

  In the SEM image, a characteristic structure in which the outer skin was rich in zeolite and the inner skin was low in zeolite could be observed. This is considered to be due to the difference in the amount of silica (weight ratio 2.4: 1) between the outer skin and the inner skin.

  About 20 g of rice husk is heated in a nitrogen stream (100 mL / min) at a heating rate of 5 K / min up to 700 ° C., held at a constant temperature of 700 ° C. for 1 hour, and then spontaneously cooled to perform firing. Was made.

Next, the SiO ₂ and H ₂ O contents in this PRH were measured, and Na ₂ O: Al ₂ O ₃ : SiO ₂ : H ₂ O = 3.17: 1: 1.93: 128 (molar ratio) As such, NaOH, Al (OH) ₃ and H ₂ O were weighed and mixed with PRH.

Next, this mixture was put in an autoclave and hydrothermally treated at 100 ° C. for 4 hours.
After hydrothermal treatment, the product was removed from the autoclave, the solid was filtered, washed with distilled water until the filtrate was pH 9 or less, and dried.

  From the X-ray diffraction result of the obtained solid, it was found to be A-type zeolite. An X-ray diffraction peak of carbon present in the same weight as the zeolite was not observed.

About 20 mg of the obtained rice husk zeolite-activated carbon composite sample (hereinafter referred to as NaA700) was weighed, placed in a sample pan, and heated at a heating rate of 30 ° C./min at 500 ° C. in a dry nitrogen stream (70 mL / min). The temperature was raised to 30 minutes and held for 30 minutes. Thereafter, the temperature was lowered to 30 ° C. at −30 ° C./min.
Next, 70 mL / min of nitrogen was supplied into water kept at 50 ° C. and bubbled to make a steam-nitrogen mixed gas having a humidity of 82% at 24 ° C., and this was passed through NaA700. It was kept at 30 ° C. until the mass became constant, and the amount of water adsorbed on NaA700 was measured.
Next, it switched to the dry nitrogen stream, heated up to 500 degreeC at 30 degree-C / min, and hold | maintained for 30 minutes until there was no mass change.
Thereafter, the temperature was lowered to 30 ° C. at −30 ° C./min.
Next, the circulating gas is switched to N ₂ + CO ₂ gas containing 0.7% by volume of CO ₂ , and a mixed gas sample containing water is brought into contact in the same manner as in the water adsorption experiment to adsorb H ₂ O and CO ₂ . The amount was measured.
After the adsorption amount became constant, the temperature was raised to 500 ° C. at 30 ° C./min, and H ₂ O + CO ₂ desorption was performed.
For comparison, molecular sieve 4A (hereinafter referred to as MS-4A) was also subjected to an H ₂ O + CO ₂ adsorption / desorption test in the same manner as NaA700. The results are summarized in Table 4.

  From the results in Table 4, compared with MS-4A, NaA700 adsorbed carbon dioxide gas containing water, although the amount of water adsorbed was small, but the amount of carbon dioxide adsorbed was larger.

[Example 3]
A-type zeolite was prepared in the same manner as in Example 2 using PRH calcined at 500 ° C.
The obtained rice husk zeolite-activated carbon composite sample (hereinafter referred to as NaA500) was subjected to an adsorption experiment of water vapor, water vapor + carbon dioxide gas in the same manner as in Example 2. In addition, adsorption experiment of dry carbon dioxide-nitrogen mixed gas was also conducted.
For comparison, a rice husk activated carbon having a specific surface area of 3000 m ² / g prepared from PRH by KOH activation was prepared, and commercially available MS-4A and this rice husk activated carbon had the same zeolite content as NaA500 and had the same surface area. A sample (hereinafter referred to as “Mixture”) prepared by mixing α-Al ₂ O ₃ having a small surface area and almost no adsorption ability and having the same weight as NaA500 was prepared. The adsorption experiment results are shown in Table 5 below.

  NaA500 is a rice husk zeolite-activated carbon composite prepared at 500 ° C. Mixture is the result of a commercial MS-4A-chaff activated carbon-α-alumina mixture. In Mixture, the amount of dry carbon dioxide adsorbed is 7.1 mg / g, but in the case of water vapor-carbon dioxide mixed gas, the amount of adsorption is less than in the case of water vapor alone, and the coexistence of water vapor prevents carbon dioxide adsorption. You can see that NaA500 has a large amount of water vapor adsorbed, and even when water vapor coexists, carbon dioxide is also adsorbed. With dry carbon dioxide, the amount of adsorption is very large. Thus, it is clear that NaA500 is not a simple mixture of zeolite and activated carbon, but zeolite and activated carbon are close to each other at the atomic level and have some interaction.

  The porous aluminosilicate-carbon composite of the present invention is capable of simultaneously adsorbing carbon dioxide gas, water, and a trace amount of harmful gas, and is a closed space in space where space saving is particularly required, or in a submarine, etc. It can be used as an adsorbent for carbon dioxide, water vapor, and trace harmful component removal equipment in special environments.

Claims (5)

Heating the silicic acid plant to 400 ° C. or higher in an inert atmosphere and baking to produce a carbide;
Next, the silicon content in the obtained carbide is examined, and an aluminosilicate in the range of Si: Al: Na = 1: 0.8 to 1.2: 2.5 to 4.0 (molar ratio) is formed. A step of preparing a mixture by adding an Al compound and an alkali metal compound or an alkaline earth metal compound and water, and then subjecting the resulting mixture to a hydrothermal reaction to produce a porous aluminosilicate-carbon composite Obtaining a body,
A porous aluminosilicate-carbon composite obtained by a production method in which the porous aluminosilicate is A-type zeolite ;
An adsorbent characterized by simultaneously adsorbing and removing at least carbon dioxide gas and moisture in a gas to be treated. 2. The method according to claim 1, further comprising the step of obtaining a composite having a large surface area by subjecting the obtained porous aluminosilicate-carbon composite to a steam activation treatment or a carbon dioxide activation treatment. Adsorbent as described in 4. The adsorbent according to claim 1 or 2, wherein the silicic acid plant is rice husk or straw. 2. The Al compound is aluminum hydroxide, and the alkali metal compound or alkaline earth metal compound is any one or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide. The adsorbent of any one of -3. The adsorbent according to any one of claims 1 to 4, wherein the adsorbent is formed into a pellet shape or a honeycomb structure.

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