Adsorbent and method for producing the same

Abstract

To provide an adsorbent containing diatomaceous earth and a basic compound, the adsorbent less prone to degradation in its adsorption performance.SOLUTION: An adsorbent for adsorbing an acidic gas is provided that contains diatomaceous earth, a basic compound, and carbohydrate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to adsorbents and methods for making adsorbents. [Background technology]

[0002] Patent Document 1 discloses an agent for removing hydrogen sulfide gas in which iron salt (III) and alkali are supported on a carrier such as diatomaceous earth. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-235244 Summary of the Invention [Problem to be solved by the invention]

[0004] In adsorbents containing diatomaceous earth and a basic compound, the crystallization of the basic compound reduces the effective surface area that reacts with the acidic gas to be adsorbed, which can result in a decrease in the adsorption performance for acidic gases. The present disclosure aims to suppress a decrease in the adsorption performance of an adsorbent containing diatomaceous earth and a basic compound. [Means for solving the problem]

[0005] The adsorbent of the present disclosure is an adsorbent for adsorbing acidic gases, and contains diatomaceous earth having a plurality of pores formed therein, a basic compound, and a carbohydrate, and the basic compound and the carbohydrate are held inside the pores of the diatomaceous earth. the carbohydrate is glucose, the basic compound is an alkali metal carbonate, and the content of the basic compound is equal to or less than the content of the diatomaceous earth. .

[0006] where: The content of the carbohydrate is equal to or less than the content of the diatomaceous earth.

[0007] From another perspective, the method for producing an adsorbent according to the present disclosure is a method for producing an adsorbent for adsorbing an acidic gas, comprising: As alkali metal carbonates and carbohydrates Glucose as and a step of dispersing the basic compound and the saccharide in water to form a dispersion; a step of mixing the dispersion with diatomaceous earth having a plurality of pores formed therein to form a mixture; and a step of removing water from the mixture to precipitate the basic compound and the saccharide inside the pores of the diatomaceous earth. The content of the basic compound dispersed in water is equal to or less than the content of diatomaceous earth mixed in the dispersion. . [Effects of the Invention]

[0008] According to the present disclosure, it is possible to suppress a decrease in the adsorption performance of an adsorbent containing diatomaceous earth and a basic compound. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail. <Adsorbent> The adsorbent according to one embodiment of the present disclosure contains diatomaceous earth, a basic compound, and a carbohydrate. In addition to the diatomaceous earth, the basic compound, and the carbohydrate, the adsorbent may also contain other additives, reactants produced by the reaction of the diatomaceous earth, the basic compound, and the carbohydrate, as needed. In the adsorbent, the basic compounds and carbohydrates are held inside a plurality of pores formed in the diatomaceous earth.

[0010] The adsorbent of this embodiment adsorbs acidic gases (hereinafter referred to as acidic gases). As will be described in detail later, in the adsorbent, a basic compound neutralizes with the acidic gas to be adsorbed by the adsorbent to produce a salt. As a result, the acidic gas to be adsorbed by the adsorbent is removed. Furthermore, if the acidic gas to be adsorbed by the adsorbent is an odorous gas, the concentration of the odorous gas is reduced by removing the acidic gas.

[0011] Next, each component constituting the adsorbent of this embodiment will be described in order. (Diatomaceous earth) Diatomaceous earth is a soil formed by the accumulation of diatom shells, and its main component is silicon dioxide. Diatomaceous earth is available in marine and freshwater varieties, and either can be used. Diatomaceous earth has a porous structure with multiple interconnected pores. Some of the pores in the diatomaceous earth are connected to the outside of the diatomaceous earth. The pore diameters of the pores in the diatomaceous earth range from approximately 0.1 μm to several tens of μm, although this varies depending on the type and origin of the diatomaceous earth.

[0012] The porous structure of diatomaceous earth allows it to adsorb water into the pores, which prevents basic compounds and carbohydrates from being released from the diatomaceous earth by the water surrounding the adsorbent in high-humidity environments. Furthermore, diatomaceous earth has a porous structure that increases its surface area, allowing it to retain a larger amount of basic compounds within its pores. This promotes the neutralization reaction between the acidic gases to be adsorbed by the adsorbent and the basic compounds.

[0013] (basic compounds) As described above, the basic compound is held inside the multiple pores formed in the diatomaceous earth. The basic compound may be present not only inside the multiple pores formed in the diatomaceous earth but also outside the pores. Details will be described later, but in the adsorbent of this embodiment, the basic compound is held in the diatomaceous earth by suppressing crystallization due to the action of the carbohydrates described below. The basic compound then undergoes a neutralizing reaction with the acidic gas to be adsorbed by the adsorbent, producing a salt.

[0014] The basic compound is not particularly limited as long as it is water-soluble and crystalline and neutralizes with the acidic gas to be adsorbed to produce a salt. Examples of such basic compounds include alkali metal carbonates, alkali metal phosphates, and alkali metal hydroxides. Among these, it is preferable to use alkali metal carbonates, and it is more preferable to use potassium carbonate, from the viewpoints of ease of suppressing crystallization by carbohydrates (described later), stability in the adsorbent, cost, etc.

[0015] (Carbohydrates) As described above, the carbohydrate is held inside the plurality of pores formed in the diatomaceous earth. Note that the carbohydrate may be present not only inside the plurality of pores formed in the diatomaceous earth but also outside the pores. In the adsorbent of this embodiment, oxygen atoms derived from oxygen in the air bond to the carbon derived from the carbohydrates obtained by heating, forming C(O) on the surface of the carbohydrates. When the acidic gas to be adsorbed is, for example, weakly acidic H2S, this C(O) serves as the starting point for an oxidation reaction, oxidizing the H2S. The oxidation of the H2S makes it more susceptible to neutralization reactions with basic compounds. This makes it possible for the adsorbent of this embodiment to remove not only highly acidic acidic gases such as SO2, but also weakly acidic H2S. Furthermore, as will be described in detail later, the carbohydrate acts as a crystallization inhibitor that inhibits the basic compound from crystallizing.

[0016] In the production of an adsorbent, carbohydrates may be dissolved or dispersed in water before use. Therefore, it is preferable to use carbohydrates that are soluble or dispersible in water. Any of monosaccharides, disaccharides, oligosaccharides, polysaccharides, etc. may be used as the carbohydrate, as long as it is soluble or dispersible in water. Examples of such carbohydrates that are soluble or dispersible in water include glucose, sucrose, and starch. Among these, glucose is preferably used because of its high effect of inhibiting the crystallization of basic compounds. While both D-glucose and L-glucose have similar effects, it is preferable to use D-glucose from the viewpoint of cost, etc.

[0017] (Other substances) The adsorbent may contain crystalline compounds such as KH(Si2O5). Such crystalline compounds may contribute to the removal of acidic gases by undergoing a neutralizing reaction with the acidic gases to be adsorbed in the adsorbent.

[0018] Furthermore, the adsorbent may contain carbon spheres formed by heating carbohydrates. Carbon spheres are spherical carbon particles with an average particle size of about several hundred nanometers.

[0019] Furthermore, the adsorbent may contain a known binder in order to improve the strength of the adsorbent. The binder is not particularly limited, but examples that can be used include cellulose derivatives such as methyl cellulose, ethyl cellulose, propyl cellulose, carboxymethyl cellulose, carboxyethyl cellulose, hydroxymethyl cellulose, and hydroxyethyl cellulose, polyvinyl alcohol, and acrylic resins.

[0020] (Content) In the adsorbent of this embodiment, the content of the basic compound varies depending on the type of basic compound and carbohydrate, but can be, for example, in the range of 50 parts by mass or more and 150 parts by mass or less per 100 parts by mass of diatomaceous earth. When the basic compound is an alkali metal carbonate, the content of the basic compound is preferably in the range of 50 parts by mass to 100 parts by mass per 100 parts by mass of diatomaceous earth. In other words, in the adsorbent of this embodiment, when the basic compound is an alkali metal carbonate, the content of the basic compound is preferably equal to or less than the content of diatomaceous earth. This allows the life of the adsorbent to be longer than when the content of the basic compound is greater than the content of diatomaceous earth.

[0021] Furthermore, in the adsorbent of this embodiment, the carbohydrate content varies depending on the type of basic compound and carbohydrate, but can be, for example, in the range of 50 parts by mass or more and 150 parts by mass or less per 100 parts by mass of diatomaceous earth. When the carbohydrate is glucose, the carbohydrate content is preferably in the range of 50 parts by mass to 100 parts by mass per 100 parts by mass of diatomaceous earth. In other words, in this embodiment, when the carbohydrate is glucose, the carbohydrate content is preferably equal to or less than the diatomaceous earth content. This allows the life of the adsorbent to be longer than when the carbohydrate content is greater than the diatomaceous earth content.

[0022] (Method of manufacturing adsorbent) Next, an example of a method for producing the adsorbent of this embodiment will be described. The adsorbent of this embodiment can be produced, for example, as follows. First, a dispersion liquid is prepared by dispersing a basic compound and a saccharide in the dispersion liquid, for example, by mixing a liquid in which a basic compound is dissolved in water with a liquid in which a saccharide is dissolved or dispersed in water.

[0023] The dispersion is then mixed with diatomaceous earth to form a mixture, for example, by gradually adding diatomaceous earth to the dispersion while stirring the dispersion. Next, the mixture is subjected to vacuum degassing treatment using a vacuum degassing mixer or the like to remove gas from the pores formed in the diatomaceous earth. This allows the basic compound and carbohydrate to easily penetrate into the pores of the diatomaceous earth. Note that vacuum degassing treatment is not necessarily required.

[0024] Next, water is removed from this mixture, causing the basic compound and carbohydrate dissolved or dispersed in the water to precipitate inside the pores of the diatomaceous earth. Here, in the step of removing water from the mixture, the crystallization of the basic compound is suppressed by the presence of a sugar in the mixture. In the description of this embodiment, "crystallization of the basic compound is suppressed" does not mean that the basic compound does not crystallize at all, but means that the size of the crystals of the basic compound precipitated by removing water from the mixture is smaller than when no sugar is contained. In this embodiment, the sugar suppresses the crystallization of the basic compound, thereby increasing the effective surface area of ​​the adsorbent where the basic compound neutralizes with the acidic gas, thereby suppressing a decrease in the adsorption performance of the adsorbent for acidic gases.

[0025] Methods for removing water from the mixture include, for example, heat drying, spin drying, vacuum drying, etc., and it is preferable to employ heat drying, which involves heating the mixture. Heating the mixture can help to suppress crystallization of the basic compound, potentially improving the ability of the adsorbent to adsorb acidic gases. Furthermore, when sugars such as monosaccharides, disaccharides, and oligosaccharides are used as the carbohydrate, heating the mixture melts the sugars and allows them to penetrate into the pores of the diatomaceous earth. This makes it easier to suppress crystallization of the basic compound that has penetrated into the pores of the diatomaceous earth, thereby increasing the effective surface area of ​​the basic compound. In this case, the temperature to which the mixture is heated is preferably equal to or higher than the melting point of the sugar.

[0026] By the above-described manufacturing method, an adsorbent containing diatomaceous earth, a basic compound, and a carbohydrate can be obtained. The obtained adsorbent may be crushed and sieved as necessary to form small pieces having a diameter within a predetermined range. [Example]

[0027] Next, the adsorbent of this embodiment will be described in more detail using examples. Note that the composition of the adsorbent, the method for producing the adsorbent, and the like are not limited to the following examples. 1. Manufacture of adsorbent Example 1 The adsorbent was obtained as follows. First, 20 g of D(+)-glucose (hereinafter simply referred to as glucose) was dissolved in 80 g of deionized water to prepare a glucose solution. Similarly, 20 g of potassium carbonate was dissolved in 80 g of deionized water to prepare a potassium carbonate solution. Next, the glucose aqueous solution and the potassium carbonate aqueous solution were mixed to produce a dispersion of glucose and potassium carbonate in deionized water.

[0028] Next, 20 g of diatomaceous earth was gradually added to the dispersion while stirring, and the mixture was then stirred for 10 minutes to produce a mixture of the dispersion and diatomaceous earth. Next, this mixture was placed in a vacuum degassing stirrer and subjected to vacuum degassing treatment for 10 minutes. Next, this mixture was placed in an electric furnace and heated at 150°C for 4 hours and then at 170°C for 4.5 hours to remove moisture from the mixture and obtain a complex containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate).

[0029] The resulting composite was then crushed using a mortar and pestle and sieved to obtain particles with particle sizes ranging from 2.00 mm to 4.75 mm, yielding a small-piece adsorbent containing diatomaceous earth, potassium carbonate, and glucose in a ratio of diatomaceous earth:potassium carbonate:glucose = 1:1:1.

[0030] Example 2 After producing the mixture, a small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate) was obtained in the same manner as in Example 1, except that the vacuum degassing treatment was not performed. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and glucose was diatomaceous earth:potassium carbonate:glucose=1:1:1.

[0031] Example 3 A small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate) was obtained in the same manner as in Example 1, except that the amount of glucose in the glucose aqueous solution was 10 g. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and glucose was diatomaceous earth:potassium carbonate:glucose=1:1:0.5.

[0032] Example 4 A small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate) was obtained in the same manner as in Example 1, except that the amount of glucose in the glucose aqueous solution was 30 g. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and glucose was diatomaceous earth:potassium carbonate:glucose=1:1:1.5.

[0033] Example 5 A small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate) was obtained in the same manner as in Example 1, except that the amount of potassium carbonate in the potassium carbonate aqueous solution was 10 g. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and glucose was diatomaceous earth:potassium carbonate:glucose=1:0.5:1.

[0034] Example 6 A small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate) was obtained in the same manner as in Example 1, except that the amount of potassium carbonate in the potassium carbonate aqueous solution was 30 g. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and glucose was diatomaceous earth:potassium carbonate:glucose=1:1.5:1.

[0035] Example 7 A small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate) was obtained in the same manner as in Example 1, except that the mixture after vacuum degassing was placed in an oil bath instead of an electric furnace, preheated for 7 hours at an oil temperature of 100°C, and then heated for 4 hours at an oil temperature of 160°C to remove moisture and form a composite. The ratio of the contents of diatomaceous earth, potassium carbonate, and glucose in this adsorbent was diatomaceous earth:potassium carbonate:glucose = 1:1:1.

[0036] Example 8 The mixture after vacuum degassing was placed in an oil bath and preheated for 7 hours at an oil temperature of 100°C, followed by heating for 4 hours at an oil temperature of 160°C. The mixture was then heated for a further 4.5 hours at an oil temperature of 195°C, and the same procedure as in Example 7 was repeated to obtain a small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and glucose (a carbohydrate). The ratio of the contents of diatomaceous earth, potassium carbonate, and glucose in this adsorbent was diatomaceous earth:potassium carbonate:glucose = 1:1:1.

[0037] Example 9 A dispersion liquid in which sucrose and potassium carbonate were dispersed in deionized water was prepared in the same manner as in Example 1, except that sugar (sucrose) was used instead of glucose. Next, 20 g of diatomaceous earth was gradually added to the dispersion while stirring, and the mixture was then stirred for 10 minutes to produce a mixture of the dispersion and diatomaceous earth. Next, this mixture was placed in a vacuum degassing stirrer and subjected to vacuum degassing treatment for 10 minutes.

[0038] Next, this mixture was placed in an electric furnace and heated at 100°C for 7 hours, 140°C for 3.5 hours, 150°C for 3 hours, 170°C for 4.5 hours, and 200°C for 4 hours to remove moisture from the mixture and obtain a complex containing diatomaceous earth, potassium carbonate (a basic compound), and sucrose (a carbohydrate). The resulting composite was then crushed using a mortar and pestle, as in Example 1, and sieved to a size range of 2.00 mm to 4.75 mm to obtain a small-piece adsorbent. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and sucrose was diatomaceous earth:potassium carbonate:sucrose=1:1:1.

[0039] Example 10 A small-piece adsorbent containing diatomaceous earth, potassium carbonate (a basic compound), and sucrose (a carbohydrate) was obtained in the same manner as in Example 9, except that the amount of sucrose was 10 g. In this adsorbent, the ratio of the contents of diatomaceous earth, potassium carbonate, and sucrose was diatomaceous earth:potassium carbonate:sucrose=1:1:0.5.

[0040] (Comparative Example 1) A small-piece adsorbent containing diatomaceous earth and the basic compound potassium carbonate was obtained in the same manner as in Example 1, except that the amount of potassium carbonate in the potassium carbonate aqueous solution was 10 g, and diatomaceous earth was added to the potassium carbonate aqueous solution without using glucose to form a mixture. In this adsorbent, the content ratio of diatomaceous earth, potassium carbonate, and glucose (sucrose) was diatomaceous earth:potassium carbonate:glucose (sucrose)=1:0.5:0.

[0041] Table 1 shows the type of saccharide, the ratio of diatomaceous earth to saccharide and basic compound, whether or not a vacuum was applied, and the heating method and heating temperature for Examples 1 to 10 and Comparative Example 1.

[0042] [Table 1]

[0043] 2. Sulfur dioxide adsorption test The adsorbents obtained in Examples 1 to 10 and Comparative Example 1 were tested for their adsorption performance using sulfur dioxide as the acid gas to be adsorbed. (1) Test method The adsorbents obtained in Examples 1 to 10 and Comparative Example 1 were subjected to air adjusted to a humidity of 45% RH and a sulfur dioxide concentration of 20 ppm at an SV (Space Velocity) value of 53,000 h -1 The sulfur dioxide concentrations in the air were measured upstream and downstream of the adsorbent, and the sulfur dioxide adsorption efficiency of each adsorbent was calculated using the upstream and downstream sulfur dioxide concentrations according to the following formula (1). The time until the adsorption efficiency fell below 85% was defined as the life of the adsorbent. Adsorption efficiency (%) = {1-(downstream sulfur dioxide concentration / upstream sulfur dioxide concentration)} x 100 ... (1)

[0044] For Examples 1 to 7, the sulfur dioxide adsorption efficiency and lifespan of each adsorbent were calculated in the same manner as above, except that the humidity of the sulfur dioxide-containing air was changed to 20% RH.

[0045] (2) Test results Table 2 shows the weight (g) of the obtained adsorbents, the life (h) measured by the above method, and the life per 1 g of adsorbent (h / g) for Examples 1 to 10 and Comparative Example 1.

[0046] [Table 2]

[0047] As shown in Table 2, the adsorbents of Examples 1 to 10, which contain diatomaceous earth, a basic compound, and a saccharide, were confirmed to adsorb sulfur dioxide, an acidic gas, in sulfur dioxide adsorption tests conducted at 45% RH and 20% RH. In contrast, the adsorbent of Comparative Example 1, which does not contain a saccharide, did not adsorb sulfur dioxide in the sulfur dioxide adsorption test conducted at 45% RH. This confirmed that an adsorbent containing diatomaceous earth, a basic compound, and a carbohydrate can suppress the decline in adsorption performance compared to an adsorbent not containing a carbohydrate.

[0048] Furthermore, when comparing Examples 1 to 10, the adsorbents of Examples 1 to 8, which contained glucose as a carbohydrate, had a longer life per gram of adsorbent in a sulfur dioxide adsorption test under a humidity condition of 45% RH than the adsorbents of Examples 9 and 10, which contained sucrose as a carbohydrate. This confirmed that in an adsorbent containing diatomaceous earth, a basic compound, and a carbohydrate, using glucose as the carbohydrate improves the adsorption performance of sulfur dioxide, an acidic gas, compared to when sucrose is used as the carbohydrate.

[0049] Next, among the adsorbents containing glucose as a carbohydrate, the adsorbents of Examples 1 and 3 to 6, which have different content ratios of diatomaceous earth, basic compound, and carbohydrate, are compared. The adsorbents of Examples 1 and 3 to 5, in which the content of basic compound is equal to or less than the content of diatomaceous earth, had a longer life per gram of adsorbent in sulfur dioxide adsorption tests at 45% RH and 20% RH compared to the adsorbent of Example 6, in which the content of basic compound is greater than the content of diatomaceous earth. This confirmed that in adsorbents containing glucose as a carbohydrate, the adsorption performance of sulfur dioxide, an acidic gas, can be improved by keeping the content of basic compounds below that of diatomaceous earth.

[0050] Next, we compare the adsorbents of Examples 1, 3 to 5, in which the content of basic compounds is equal to or less than the content of diatomaceous earth. The adsorbents of Examples 1, 3, and 5, in which the content of glucose is equal to or less than the content of diatomaceous earth, had a longer life per gram of adsorbent in a sulfur dioxide adsorption test at a humidity of 45% RH than the adsorbent of Example 4, in which the content of glucose is greater than the content of diatomaceous earth. This confirmed that in adsorbents containing glucose as a carbohydrate, the adsorption performance of sulfur dioxide, an acidic gas, can be improved by making the glucose content less than or equal to the content of diatomaceous earth.

[0051] 3. Hydrogen sulfide adsorption test The adsorption performance of the adsorbents obtained in Examples 2, 3, and 5 and Comparative Example 1 was tested using hydrogen sulfide as the acidic gas to be adsorbed. (1) Test method The adsorbents obtained in Examples 2, 3, and 5 and Comparative Example 1 were subjected to an SV value of 5,252 h with air adjusted to a humidity of 50% RH and 200 ppm hydrogen sulfide. -1 The hydrogen sulfide concentrations in the air were measured upstream and downstream of the adsorbent, and the hydrogen sulfide adsorption efficiency of each adsorbent was calculated using the upstream and downstream hydrogen sulfide concentrations according to the following formula (2). The time until the adsorption efficiency fell below 85% was defined as the life of the adsorbent. Adsorption efficiency (%) = {1 - (hydrogen sulfide concentration downstream / hydrogen sulfide concentration upstream)} × 100 ... (2)

[0052] (2) Test results Table 3 shows the weight (g) of the obtained adsorbents, the life (h) measured by the above method, and the life per 1 g of adsorbent (h / g) for Examples 2, 3, 5 and Comparative Example 1.

[0053] [Table 3]

[0054] As shown in Table 3, the adsorbents of Examples 2, 3, and 5, which contain diatomaceous earth, a basic compound, and a carbohydrate, were confirmed to adsorb hydrogen sulfide, a weakly acidic gas, in a hydrogen sulfide adsorption test. Furthermore, when the adsorbents of Examples 2, 3, and 5, which contain diatomaceous earth, a basic compound, and a carbohydrate, were compared with the adsorbent of Comparative Example 1, which does not contain a carbohydrate, the adsorbents of Examples 2, 3, and 5 had a longer life per gram of adsorbent in the hydrogen sulfide adsorption test than the adsorbent of Comparative Example 1. This confirmed that an adsorbent containing diatomaceous earth, a basic compound, and a carbohydrate has improved adsorption performance for hydrogen sulfide, a weakly acidic gas, compared to an adsorbent that does not contain a carbohydrate.

[0055] 4. Estimation of the crystal structure of the adsorbent The crystal structures of the adsorbents obtained in Examples 1 to 6 were estimated by X-ray diffraction. For the adsorbent of Example 1, a diffraction peak corresponding to KH(SiO5) was observed. For the adsorbents of Examples 2, 3, and 6, diffraction peaks corresponding to KH(SiO5) and K4H2(CO3)3·1.5H2O were observed. For the adsorbent of Example 4, diffraction peaks corresponding to K4H2(CO3)3·1.5H2O and K2CO3·1.5H2O were observed. On the other hand, for the adsorbent of Example 5, no diffraction peaks corresponding to compounds other than diatomaceous earth and carbohydrates were observed.

[0056] Here, each of the above-described embodiments can be understood as follows. The adsorbent of this embodiment is an adsorbent for adsorbing acidic gases, and contains diatomaceous earth, a basic compound, and a carbohydrate. In this case, the deterioration of the adsorption performance of the adsorbent containing diatomaceous earth and a basic compound can be suppressed compared to when the adsorbent does not contain a carbohydrate.

[0057] The carbohydrate may also be glucose. In this case, the ability of the adsorbent to adsorb acidic gases can be improved compared to when a carbohydrate other than glucose is used.

[0058] The basic compound may also be an alkali metal carbonate. In this case, the sugar can more effectively suppress crystallization of the basic compound than when a basic compound other than an alkali metal carbonate is used.

[0059] The content of the basic compound may be equal to or less than the content of the diatomaceous earth. In this case, the ability of the adsorbent to adsorb acidic gases can be improved compared to when the content of the basic compound is greater than the content of diatomaceous earth.

[0060] The content of carbohydrates may be equal to or less than the content of diatomaceous earth. In this case, the ability of the adsorbent to adsorb acidic gases can be improved compared to when the sugar content is greater than the diatomaceous earth content.

[0061] From another perspective, the method for producing an adsorbent of this embodiment is a method for producing an adsorbent for adsorbing acidic gases, and includes the steps of producing a dispersion in which a basic compound and a carbohydrate are dispersed in water, producing a mixture in which the dispersion is mixed with diatomaceous earth, and removing water from the mixture. In this case, the sugar can suppress crystallization of the basic compound, and the deterioration of the adsorption performance of the adsorbent containing diatomaceous earth and the basic compound can be suppressed.

[0062] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims.

Claims

1. An adsorbent for adsorbing acid gases, comprising: Diatomaceous earth having a plurality of pores formed therein; a basic compound; Carbohydrates and Contains the basic compound and the carbohydrate are held within the pores of the diatomaceous earth; the carbohydrate is glucose, the basic compound is an alkali metal carbonate, The content of the basic compound is equal to or less than the content of the diatomaceous earth. Adsorbent material.

2. 2. The adsorbent according to claim 1, wherein the content of the carbohydrate is equal to or less than the content of the diatomaceous earth.

3. A method for producing an adsorbent for adsorbing acid gases, comprising: a step of dispersing an alkali metal carbonate as a basic compound and glucose as a carbohydrate in water to produce a dispersion; a step of mixing the dispersion with diatomaceous earth having a plurality of pores to form a mixture; removing water from the mixture and precipitating the basic compound and the saccharide inside the pores of the diatomaceous earth; and The content of the basic compound dispersed in water is equal to or less than the content of diatomaceous earth mixed in the dispersion. Method for manufacturing adsorbent.

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