Method for producing a porous material, porous material obtained thereby, and Si source composition for producing a porous material

Abstract

Provided is a technique that enables effective utilization of plant-derived Si sources.　This technique can provide a method for producing a porous material containing Si and Al, the method using at least a first Si-source composition, which is a plant-derived Si source, and an Al source as raw materials. The first Si-source composition may be a Si source that is recovered by a Si recovering process conducted after the plant-derived raw material is subjected to a carbonization process. A second Si-source composition may be a processed substance obtained by subjecting the plant-derived raw material to a decarbonization process.

Description

Technical Field

[0001] The present technology relates to a method for producing a porous material, a porous material obtained thereby, and a Si source composition for producing a porous material.

Background Art

[0002] In agriculture and industry, a large amount of by-products are generated. However, most of these by-products are discarded without being utilized. In order to discard this by-product, energy for disposal (for example, incineration) is required, and waste treatment facilities, incineration facilities, final disposal sites, etc. are also required. Discarding by-products places a burden on the global environment and tends to increase costs.

[0003] For example, in Patent Document 1, after carbonizing a plant-derived material at 800°C to 1400°C and then treating it with an acid or an alkali, a method for producing a porous carbon material using a plant-derived material as a raw material, with a silicon content of 10% by weight or more using a plant-derived material as a raw material, a specific surface area value by the nitrogen BET method of 10 m 2 / gram or more, a silicon content of 1% by weight or less, and a pore volume of 0.1 cm 3 / gram or more, it has been proposed that a porous carbon material can be obtained and used, for example, as a negative electrode material for a battery, an adsorbent, a mask, an adsorption sheet, or a carrier. Further, Patent Document 2 discloses a porous carbon material using a plant containing at least one component selected from the group consisting of sodium, magnesium, potassium, and calcium as a raw material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Furthermore, it is necessary to further promote the effective utilization of Si sources derived from plants generated in agriculture, industry, etc. Therefore, the main object of this technology is to provide a technology capable of effectively using Si sources derived from plants.

Means for Solving the Problems

[0006] As a result of intensive studies, the present inventors have found that various porous materials can be produced by using Si sources obtained from plant-derived raw materials. In this way, a technology capable of effectively using Si sources derived from plants can be provided, and this technology has been completed. In this technology, the Si source derived from plants may be a plant-derived by-product.

[0007] This technology can provide a method for producing a porous material containing Si and Al, which uses at least a first Si source composition that is a Si source derived from plants and an Al source as raw materials. Furthermore, a second Si source composition may be used as a raw material. The first Si source composition may be a Si source recovered when a process of recovering the Si source is performed after carbonizing a plant-derived raw material. The process of recovering the Si source may be a process by alkali extraction performed by adjusting the NaOH / Si molar ratio (theoretical ratio). The first Si source composition may have a silicon content of 10 g / L or more. The Si / Al composition ratio (mass ratio) of the first Si source composition may be 1 to 300. The second Si source may be a Si source derived from minerals and / or a Si source derived from plants. The second Si source composition may be a processed product obtained by decarbonizing a plant-derived raw material. The second Si source composition may be plant-derived ash. The first Si source composition is a Si source recovered by subjecting a plant-derived raw material to carbonization treatment and then performing a treatment for recovering the Si source, and the second Si source composition may be plant-derived ash. Furthermore, an organic structure-directing agent may be used as a raw material. Heat treatment of a mixture of the first Si source composition, which is a plant-derived Si source, and the Al source may be performed. The mixture may further contain a second Si source composition. The heat treatment may be hydrothermal synthesis. The heat treatment may be in the order of aging and then hydrothermal synthesis. The first Si source composition may be an aqueous solution recovered by removing silica from a plant-derived raw material containing silica. The porous material may be zeolite. The plant may be a gramineous plant.

[0008] Also, the present technology can provide a porous material obtained by the method for producing the porous material. Also, the present technology can provide a Si source composition for producing a porous material, which contains a Si source recovered by subjecting a plant-derived raw material to carbonization treatment and then performing a treatment for recovering the Si source.

Brief Description of Drawings

[0009]

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Embodiments for Carrying out the Invention

[0010] The embodiments described below show an example of typical embodiments of the present technology, and the scope of the present technology is not construed narrowly thereby. Hereinafter, preferred embodiments for carrying out the present technology will be described with reference to the drawings and the like. Regarding the drawings, the same or equivalent elements or members are denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. In this specification, percentages are by mass unless otherwise specified. Also, the upper and lower limit values of each numerical range can be arbitrarily combined as desired. The description in this specification will be carried out in the following order.

[0011] <1. Overview of the Present Technology> <2. Manufacturing Method of the Porous Material of the Present Technology> 2-1. Raw Materials 2-1-1. First Si Source Composition 2-1-1-1. Composition of the First Si Source Composition 2-1-1-2. Plant-Derived Si Source and Its Manufacturing Method 2-1-1-3. Manufacturing Method of the First Si Source Composition 2-1-1-3-1) Plant-Derived Material (Raw Material) 2-1-1-3-2) Carbonization Treatment 2-1-1-3-3) Pretreatment of carbonization (pre-carbonization treatment) 2-1-1-3-4) Si source removal treatment (Si source recovery treatment) 2-1-1-3-4-1) Alkali treatment 2-1-1-3-4-1a) Alkali extraction 2-1-1-3-4-2) Acid treatment 2-1-2. Composition containing the first Si source 2-1-3. Porous carbon material after Si source treatment 2-1-4. Second Si source composition 2-1-4-1. Method for producing a plant-derived second Si source composition 2-1-5. Al source 2-1-6. Alkali metal source 2-1-7. Organic structure-directing agent (OSDA) 2-1-8. Amount of water 2-2. Manufacturing process of the porous material 2-2-1. Gel composition of the raw material 2-2-2. Aging 2-2-3. Hydrothermal synthesis 2-2-4. Recovery of inorganic porous material (preferably zeolite) 2-2-5. Manufacturing examples of inorganic porous materials (preferably zeolite) 2-2-5-1) Method for producing LTA-type zeolite 2-2-5-2) Method for producing CHA-type zeolite 2-2-5-3) Method for producing FAU-type zeolite <3. Porous material of the present technology> <4. Si source composition for producing porous material> <5. Each measurement method of the present technology>

[0012] <1. Outline of the present technology> Plants such as vegetables, grains, and trees are utilized in a wide range of industries such as agriculture, forestry, and industry. In fact, a large amount of by-products are generated when harvesting or processing these plants. Since the utilization of plants is regarded as one of the specific measures against climate change, it is possible to contribute to the global environment by promoting the more effective utilization of plant-derived by-products and waste.

[0013] Therefore, the present inventors conducted extensive studies on more effectively utilizing plant-derived by-products and waste as recovered materials. For example, efficient increase in grain production is beneficial from the perspective of the increasing global population. However, when processing whole grains (such as brown rice, wheat, etc.) from grains, husks and stems are generated as by-products and waste. Disposal of such a large amount of by-products and waste requires incineration or landfill. Also, for example, porous carbon materials such as activated carbon and high-purity carbon materials are processed from husks (such as coconut husks, walnut husks, rice husks), stems (such as bamboo, etc.), wood, etc. When processing the porous carbon materials, cleaning is performed to obtain high-purity carbon, and by-products and waste are generated at this time. Incidentally, this porous carbon material is widely used in electrodes and negative electrode active materials of fuel cells (such as lithium-ion secondary batteries, etc.), and adsorbents (such as for medical use, air purification, water treatment, etc.).

[0014] Considering such circumstances, when manufacturing a porous carbon material from a plant-derived raw material, the present inventors focused on the components of the waste liquid recovered to further purify the precursor of the porous carbon material. Since this recovered material contains silica, the present inventors examined what kind of high-functional materials can be converted from this recovered material containing silica as a plant-derived Si source.

[0015] As a result of extensive trial and error, the present inventors found that a porous material containing Si and Al can be manufactured by using at least a plant-derived recovered material containing a first Si source and an Al source as raw materials. Furthermore, the present inventors found that a porous material containing Si and Al can be manufactured by using at least a plant-derived recovered material containing a first Si source, a second Si source, and an Al source as raw materials. Thereby, it was possible to achieve providing a technique for effectively utilizing a plant-derived Si source, which is one of the objects of the present technology.

[0016] Specifically, in the manufacturing process of the porous carbon material based on plant-derived raw materials, the discharged Si source can be converted into a valuable material, an inorganic porous material, which is one of the high-functional materials. As a result, the discarded Si source can be effectively utilized and the disposal cost can also be reduced. However, in the present invention, the plant-derived Si source does not have to be a plant-derived by-product, and the Si source obtained from plant-derived raw materials can be used.

[0017] Conventionally, silicic acid derived solely from minerals (such as silica, silica sand, etc.) has been used as the raw material for the Si source of inorganic porous materials. Since the silicic acid derived from minerals is obtained by mining minerals and firing and purifying them at a high temperature of, for example, 1000°C, the manufacturing energy is high. On the other hand, the plant-derived recovered product containing the Si source of the present technology can be manufactured by heating at 500°C to 100°C, which is lower than the firing temperature of the silicic acid derived from minerals. Therefore, in the present technology, compared with the case of using the conventional silicic acid derived from minerals, the manufacturing energy can be significantly reduced, and in the present technology, the plant-derived Si source (such as by-products) can be reused. This is also beneficial from the perspective of global warming. Conventionally, zeolite of the mineral-based Si source has been industrially produced, but according to the present technology, zeolite can be industrially provided only with the plant-based Si source. Note that the mineral in the present technology refers to a naturally occurring inorganic crystalline substance formed by geological action.

[0018] As described above, the present technology can convert the plant-derived Si source into an inorganic porous material, which is one of the high-functional materials. The present technology can obtain an inorganic porous material with reduced manufacturing energy compared to the case of using the conventional mineral-derived Si source. Also, when using plant-derived by-products, etc., the discarded materials can be effectively utilized and the disposal cost can also be reduced.

[0019] In this technology, inorganic porous materials (preferably silicate-based porous materials) can be manufactured in a wide variety of ways. As porous materials, for example, they can be used as molecular sieves (e.g., for petroleum refining), ion exchange materials (e.g., for petroleum refining, water purification (for beverages, ultrapure water, etc.), heavy metal adsorption (e.g., cesium, strontium, etc.)), catalysts, and adsorbents (e.g., for various gas adsorption, etc.).

[0020] This technology can manufacture zeolites (zeolite) among these silicate-based porous materials. Zeolite is a microporous crystalline aluminosilicate, and generally, it is said that it can be represented by M n+ x / n Al x Si y O 2x+2 yx- ·zH2O. Zeolites can be obtained as minerals that occur naturally by mining from nature. However, it is advantageous to obtain various zeolites or zeolites with stable quality by artificial synthesis as in this technology.

[0021] The zeolites in this technology are not particularly limited, but as zeolites, for example, there are various structures such as type A (LTA), type Y (FAU), mordenite (MOR), beta type (BEA), ZSM-5 (MFI), zeolite Y or zeolite X (FAU), SSZ-13 (CHA), GIS, etc. It should be noted that the notations in parentheses are the structure codes defined by the International Zeolite Association. According to this technology, zeolites having various structures and properties can be artificially synthesized.

[0022] <2. Manufacturing method of the porous material of this technology> The present technology can provide a method for producing a porous material containing Si and Al, which uses at least a first Si source composition containing a plant-derived Si source and an Al source as raw materials. It is preferable to further use a second Si source composition as a raw material. Also, the first Si source composition and / or the second Si source composition is preferably a plant-derived Si source (e.g., recovered materials, by-products, etc.). A typical example of the method for producing the porous material of the present technology is shown, but the present technology is not limited thereto.

[0023] According to the present technology, a technology capable of effectively utilizing a plant-derived Si source can be provided. More preferably, a Si source (e.g., recovered materials, by-products, etc.) generated when producing a product (main product) from a plant raw material can be effectively utilized. Also, a Si source (e.g., recovered materials, by-products, etc.) that was conventionally discarded can be effectively utilized. Note that the effects of the present technology are not necessarily limited to the effects described herein, and may be any of the effects described in the present disclosure.

[0024] 2-1. Raw materials 2-1-1. First Si source composition The first Si source composition used as a raw material in the present technology is a composition containing a first Si source. The first Si source composition is preferably a plant-derived Si source (e.g., recovered materials, by-products, etc.), and at least a Si source (preferably silica) is contained in the by-products, etc. For this reason, it is preferable to produce the first Si source composition using a plant-derived raw material containing a Si source. More preferably, when producing this, after carbonizing the plant-derived raw material, the first Si source composition is obtained by a process of recovering the Si source. The process is more preferably an alkali treatment, and the alkali treatment is more preferably an alkali extract obtained by adjusting the NaOH / Si molar ratio (theoretical ratio) in the recovered material. In this technology, the by-product refers to other products generated concomitantly in the process of manufacturing the main target product from plant raw materials. As the Si source, a Si source that has been conventionally discarded (for example, recovered materials, by-products, etc.) is preferable, whereby the disposal cost can be reduced and the discarded Si source (for example, recovered materials, by-products, etc.) can be effectively utilized.

[0025] 2-1-1-1. Composition of the first Si source composition For the first Si source composition of this technology, a plant-derived Si source (for example, recovered materials, etc.) described later can be used. Therefore, it is preferable that the composition of the first Si source composition of this technology (here, the components constituting it and the ratio of their amounts) is the same as the composition of the plant-derived Si source. In this technology, using the plant-derived Si source as the first Si source composition as it is (about 100% by mass) is more preferable from the viewpoint of effectively utilizing the discarded Si source. Also, if necessary, optional components can be blended into the plant-derived Si source to form the first Si source composition. However, from the viewpoint of effectively utilizing the discarded Si source, it is preferable that the first Si source composition is at least 90% by mass or more, and more preferably substantially a plant-derived Si source.

[0026] The form of the first Si source composition is not particularly limited, and examples include liquid, semi-solid, solid (for example, powdery, pulverized, etc.). When the discarded Si source (for example, recovered materials, etc.) is an aqueous solution, it is preferable to use the first Si source composition in an aqueous solution state from the viewpoint of suppressing manufacturing energy.

[0027] In the manufacturing method of the present technology, by using a plant-derived Si source, various porous materials (for example, zeolite MFI type, LTA type, CHA type, Nap (GIS type), FAU type (zeolite X, zeolite Y), mordenite (MOR type), sodalite (SOD type), etc.) can be obtained. Therefore, it is considered that the plant-derived Si source contributes to the efficient production of porous materials. Furthermore, in the manufacturing method of the present technology, by using a plant-derived Si source, a pure phase of LTA-type zeolite, a single phase of CHA-type zeolite, almost pure zeolite A (LTA type) and zeolite X (FAU type), etc. can be produced better, and at this time, synthesis without an organic structure-directing agent (OSDA) is also possible. In addition, in order to effectively utilize the plant-derived Si source, components generated in the manufacturing process may be contained as long as the effects of the present technology are not impaired.

[0028] The composition in the first Si source composition preferably contains at least silicon (Si), aluminum (Al), and an alkali metal (for example, Na, K, etc.). The alkali metal is not particularly limited, and examples include sodium, potassium, lithium, etc. It is preferable to use one or more selected from these groups, and more preferably sodium.

[0029] The Si / Al composition ratio (mass / mass) in the first Si source composition is not particularly limited, but as its preferable lower limit value, it is preferably 1 or more, more preferably 10 or more, still more preferably 25 or more, more preferably 50 or more, more preferably 70 or more. Also, as its preferable upper limit value, it is preferably 300 or less, more preferably 200 or less, still more preferably 150 or less, even more preferably 120 or less, more preferably 100 or less. The preferable numerical range of the Si / Al composition ratio (mass ratio) in the first Si composition is more preferably 1 to 300, more preferably 1 to 120, still more preferably 50 to 100.

[0030] The Si / Al composition ratio (mass / mass) in the first Si source composition is not particularly limited, but as a preferable lower limit value, it is preferably 1 or more, more preferably 10 or more, still more preferably 25 or more, even more preferably 50 or more, and even more preferably 70 or more. As a preferable upper limit value, it is preferably 300 or less, more preferably 200 or less, still more preferably 150 or less, even more preferably 120 or less, and even more preferably 100 or less. The preferable numerical range of the Si / Al composition ratio (mass ratio) in the first Si composition is more preferably 1 to 300, more preferably 1 to 120, and still more preferably 50 to 100. In addition, these preferable upper limit values and lower limit values, etc. may be the preferable upper limit value and the preferable lower limit value of the Si source composition obtained by the alkali treatment without adjusting the molar ratio (theoretical ratio) of NaOH / Si and the Si source composition obtained by the acid treatment. When using such a first Si source composition with a Si / Al composition ratio (mass / mass) as a raw material, it is desirable to use the second Si source composition and the Al source as raw materials. By using such a first Si source composition, MFI-type zeolite, mordenite (MOR-type zeolite), etc. can be produced more favorably.

[0031] In addition, in the case of the first Si source composition obtained by the treatment by alkali extraction performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si, the Si / Al composition ratio (mass / mass) in the first Si source composition is not particularly limited, but as a preferable lower limit value, it is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.1 or more. As a preferable upper limit value, it is preferably 100 or less, more preferably 50 or less, and still more preferably 30 or less. As the preferable numerical range, it is more preferably 0.01 to 100, more preferably 0.05 to 50, and even more preferably 0.1 to 30. When using the first Si source composition obtained by the treatment by alkali extraction performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, it is desirable to use the Al source as a raw material without using the second Si source composition. By using such a first Si source composition, LTA-type zeolite and CHA-type zeolite can be produced more favorably. Even when the range of the Si / Al composition ratio (mass / mass) in the first Si source composition is not suitable, an Al source may be added to the first Si source composition to appropriately adjust it to the Si / Al composition ratio (mass / mass) of the desired gel composition ratio in the raw material.

[0032] The Si / Na composition ratio (mass / mass) in the first Si source composition is not particularly limited, but as its preferable lower limit value, it is preferably 0.01 or more, more preferably 0.05 or more, still more preferably 0.1 or more, and even more preferably 0.2 or more. Also, as its preferable upper limit value, it is preferably 3 or less, more preferably 2.5 or less or 1 or less, etc. The preferable numerical range is more preferably 0.01 to 3, and more preferably 0.2 to 2.5.

[0033] The Si / Na composition ratio (mass / mass) in the first Si source composition is not particularly limited, but as its preferable lower limit value, it is preferably 0.01 or more, more preferably 0.05 or more, still more preferably 0.1 or more, and even more preferably 0.2 or more. Also, as its preferable upper limit value, it is preferably 1 or less, more preferably 0.7 or less, still more preferably 0.5 or less, and even more preferably 0.3 or less. From the viewpoint of manufacturing MFI-type zeolite and mordenite (MOR-type zeolite), the preferable numerical range of the Si / Al composition ratio (mass ratio) in the first Si composition is more preferably 0.01 to 1, and more preferably 0.2 to 0.5. In addition, these preferable upper limit values and lower limit values, etc. may be the preferable upper limit value and the preferable lower limit value of the Si source composition obtained by the alkali treatment without adjusting the molar ratio (theoretical ratio) of NaOH / Si and the Si source composition obtained by the acid treatment. When using such a first Si source composition having a Si / Na composition ratio (mass / mass) as a raw material, it is desirable to use the second Si source composition and the Al source as raw materials. By using such a first Si source composition, MFI-type zeolite, mordenite (MOR-type zeolite), etc. can be manufactured more favorably.

[0034] In the case of the first Si source composition obtained by the treatment by alkali extraction performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si, the Si / Na composition ratio (mass / mass) in the first Si source composition is not particularly limited, but as its preferable lower limit value, preferably 0.1 or more, more preferably 0.3 or more, 1.0 or more, 1.5 or more, or 2.0 or more can be mentioned. Further, as its preferable upper limit value, preferably 3 or less, 2.5 or less, 1.0 or less, or 0.7 or less can be mentioned. The preferable numerical range of the Si / Al composition ratio (mass ratio) in the first Si composition is preferably 0.3 to 2.5.

[0035] When producing CHA-type mordenite better using the first Si source composition obtained by the treatment by alkali extraction performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, the Si / Na composition ratio (mass / mass) in the first Si source composition, as its preferable lower limit value, is preferably 1.0 or more, more preferably 1.5 or more, still more preferably 1.8 or more. Further, as its preferable upper limit value, preferably 3.0 or less, more preferably 2.5 or less, still more preferably 2.3 or less. As the preferable numerical range, more preferably it is 1.8 to 2.5.

[0036] Also, when producing LTA-type mordenite and FAU-type zeolite better using the first Si source composition obtained by the treatment by alkali extraction performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, the Si / Na composition ratio (mass / mass) in the first Si source composition, as its preferable lower limit value, is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more. Further, as its preferable upper limit value, preferably 1.3 or less, more preferably 1.0 or less, still more preferably 0.8 or less. As the preferable numerical range, more preferably it is 0.3 to 1.0.

[0037] The content (g / L) of Si (silicon) in the first Si source composition is not particularly limited, but as its preferable lower limit value, it is preferably 10 g / L or more, more preferably 20 g / L or more, still more preferably 25 g / L or more. Also, as its preferable upper limit value, it is preferably 500 g / L or less, more preferably 450 g / L or less, still more preferably 400 g / L or less, preferably 300 g / L or less. The preferable numerical range of this preferable value is more preferably 10 to 500 g / L, and more preferably 20 to 300 g / L.

[0038] The content (g / L) of Si (silicon) in the first Si source composition is not particularly limited, but as its preferable lower limit value, it is preferably 25 g / L or more, more preferably 50 g / L or more, still more preferably 100 g / L or more, more preferably 150 g / L or more, more preferably 200 g / L or more. Also, as its preferable upper limit value, it is preferably 500 g / L or less, more preferably 450 g / L or less, still more preferably 400 g / L or less, preferably 300 g / L or less. From the viewpoint of manufacturing MFI-type zeolite and mordenite (MOR-type zeolite), the preferable numerical range of the Si content (g / L) in the first Si composition is more preferably 50 to 500 g / L, and more preferably 100 to 300 g / L. In addition, these preferable upper limit values and lower limit values, etc. may be the preferable upper limit value and preferable lower limit value of the Si source composition obtained by alkali treatment without adjusting the molar ratio (theoretical ratio) of NaOH / Si and the Si source composition obtained by acid treatment. When using such a first Si source composition with a Si (silicon) content (g / L) as a raw material, it is desirable to use the second Si source composition and the Al source as raw materials. By using such a first Si source composition, MFI-type zeolite, mordenite (MOR-type zeolite), etc. can be manufactured more favorably.

[0039] In the case of the first Si source composition obtained by the treatment by alkali extraction carried out by adjusting the molar ratio (theoretical ratio) of NaOH / Si, the content (g / L) of Si (silicon) in the first Si source composition is not particularly limited. However, as its preferable lower limit value, preferably 20 g / L or more, more preferably 23 g / L or more, still more preferably 25 g / L or more or 28 g / L or more can be mentioned. Also, as its preferable upper limit value, preferably 100 g / L or less, more preferably 50 g / L or less, still more preferably 40 g / L or less, 38 g / L or less or 29 g / L or less etc. can be mentioned. As the preferable numerical range, it is preferably 20 to 50 g / L.

[0040] When producing CHA type mordenite better using the first Si source composition obtained by the treatment by alkali extraction carried out by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, the content (g / L) of Si (silicon) in the first Si source composition, as its preferable lower limit value, preferably 20 g / L or more, more preferably 23 g / L or more, still more preferably 24 g / L or more, more preferably 25 g / L or more. Also, as its preferable upper limit value, preferably 33 g / L or less, more preferably 30 g / L or less, still more preferably 29 g / L or less, more preferably 28 g / L or less. As the preferable numerical range, more preferably 23 to 30 g / L.

[0041] Also, when producing LTA type mordenite and FAU type zeolite better using the first Si source composition obtained by the treatment by alkali extraction carried out by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, the content (g / L) of Si (silicon) in the first Si source composition may be in the following range. As its preferable lower limit value, preferably 28 g / L or more, more preferably 30 g / L or more, still more preferably 32 g / L or more, more preferably 33 g / L or more. Also, as its preferable upper limit value, preferably 40 g / L or less, more preferably 39 g / L, still 38 g / L or less, more preferably 37 g / L or less. As the preferable numerical range, more preferably 32 to 38 g / L.

[0042] The Na content (g / L) in the first Si source composition is not particularly limited, but its preferred lower limit is preferably 5 g / L or more, more preferably 10 g / L or more or 50 g / L or more. Also, its preferred upper limit is preferably 1000 g / L or less, more preferably 950 g / L or less, still more preferably 900 g / L or less, preferably 850 g / L or less. The preferred numerical range is more preferably 5 to 900 g / L.

[0043] The Na content (g / L) in the first Si source composition is not particularly limited, but its preferred lower limit is preferably 100 g / L or more, more preferably 200 g / L or more, still more preferably 300 g / L or more, more preferably 400 g / L or more, more preferably 500 g / L or more, more preferably 600 g / L or more. Also, its preferred upper limit is preferably 1000 g / L or less, more preferably 950 g / L or less, still more preferably 900 g / L or less, preferably 850 g / L or less. The preferred numerical range of the Na content (g / L) in the first Si composition is more preferably 50 to 900 g / L, and more preferably 100 to 850 g / L from the viewpoint of manufacturing MFI-type zeolite and mordenite (MOR-type zeolite). Note that these preferred upper and lower limits, etc. may also be the preferred upper limit and preferred lower limit of the Si source composition obtained by alkali treatment without adjusting the molar ratio (theoretical ratio) of NaOH / Si and the Si source composition obtained by acid treatment. When using such a first Si source composition with an Si / Na composition ratio (mass / mass) as a raw material, it is desirable to use the second Si source composition and the Al source as raw materials. By using such a first Si source composition, MFI-type zeolite, mordenite (MOR-type zeolite), etc. can be manufactured better.

[0044] In the case of the first Si source composition obtained by the treatment by alkali extraction carried out by adjusting the molar ratio (theoretical ratio) of NaOH / Si, the Na content (g / L) in the first Si source composition is not particularly limited, but as its preferable lower limit value, it is preferably 5 g / L or more, more preferably 8 g / L or more, still more preferably 10 g / L or more, 20 g / L or more, 30 g / L or more, 40 g / L or more, or 50 g / L or more. Also, as its preferable upper limit value, it is preferably 100 g / L or less, more preferably 80 g / L or less, still more preferably 70 g / L or less, and more preferably 60 g / L or less. As the preferable numerical range, it is more preferably 10 to 80 g / L.

[0045] When producing CHA-type zeolite better using the first Si source composition obtained by the alkali treatment by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, the Na content (g / L) in the first Si source composition, as its preferable lower limit value, is preferably 5 g / L or more, more preferably 8 g / L or more, still more preferably 9 g / L or more, and more preferably 10 g / L or more. Also, as its preferable upper limit value, it is preferably 20 g / L or less, more preferably 18 g / L or less, still more preferably 16 g / L or less, more preferably 15 g / L or less, and more preferably 14 g / L or less. As the preferable numerical range, it is more preferably 8 to 15 g / L.

[0046] Also, when producing LTA-type zeolite and FAU-type zeolite better using the first Si source composition obtained by the alkali treatment by adjusting the molar ratio (theoretical ratio) of NaOH / Si as a raw material, the Na content (g / L) in the first Si source composition, as its preferable lower limit value, is preferably 20 g / L or more, more preferably 30 g / L or more, still more preferably 40 g / L or more, more preferably 45 g / L or more, and more preferably 50 g / L or more. Also, as its preferable upper limit value, it is preferably 80 g / L or less, more preferably 70 g / L or less, still more preferably 65 g / L or less, and more preferably 60 g / L or less. As the preferable numerical range, it is more preferably 30 to 70 g / L.

[0047] The pH in the first Si source composition is preferably in the alkaline region (preferably 8 to 14), more preferably 10 or more, still more preferably 11 or more, further more preferably 12 or more, and even more preferably 13 or more. In addition, the content, composition ratio, and mass ratio of each element in the first Si source composition can be measured by ICP emission analysis, and it is preferably measured in a state of g / 1 L (volume) of water.

[0048] 2-1-1-2. Plant-derived Si source and its manufacturing method The plant-derived Si source (for example, recovered materials, by-products, waste, etc.) used in the present technology is preferably the same as the composition of the above-described first Si source composition (here, the components constituting it and the ratio of their amounts). Specifically, in the plant-derived Si source, the Si / Al composition ratio (mass ratio), Si / Na composition ratio (mass ratio), Si content (g / L), silica content (g / L), Al content (g / L), content of alkali metal (for example, Na) (g / L), water content, etc. are preferably the same as the composition of the above-described first Si source composition.

[0049] The "plant" in the plant-derived Si source is not particularly limited, and examples include plants (for example, terrestrial plants, algae, etc.) that can be used in the production of the porous carbon material described later. Among these, gramineous plants are preferred from the viewpoint of effective utilization, and plants with an Si content rate of the used part preferably 4% by mass or more, more preferably 5% by mass or more are preferred. Among these gramineous plants, more preferably, it is one or more selected from the group consisting of rice (paddy), wheat (for example, barley, wheat, rye, etc.). In addition, the part of the plant used is not particularly limited, but the outer skin and / or stem are preferred, and more preferably the outer skin (husk). In the case of rice (paddy), husk and / or straw are preferred from the viewpoints of production energy and effective utilization.

[0050] 2-1-1-3. Manufacturing method of the first Si source composition In this technology, the first Si source composition uses a plant-derived material as a raw material, carbonizes the plant-derived raw material, and from the carbonized material, a recovered product (more preferably, a by-product, waste, etc.) from which the Si source is recovered through processes such as Si source recovery treatment, Si source removal treatment, and washing treatment is suitable. Furthermore, from the perspective of effective utilization of waste, it is preferable that it is a Si source (such as a by-product, etc.) generated in the manufacturing process of a porous carbon material (main product) using a plant-derived material as a raw material.

[0051] More preferably, the first Si source composition in this technology is preferably the material removed at this time after carbonizing the plant-derived raw material and performing a treatment to remove the Si source. Note that the manufacturing method of the first Si source composition of this technology is not particularly limited thereto. The manufacturing method of the first Si source composition of this technology can be manufactured, for example, with reference to Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-273816), Patent Document 2 (Japanese Patent Application Laid-Open No. 2012-179589), etc.

[0052] Furthermore, an example of a more specific manufacturing method of the first Si source composition will be described below, but this technology is not limited thereto. The manufacturing process of the porous carbon material using the plant-derived material as a raw material will be described. The manufacturing process of the porous carbon material preferably includes carbonizing the plant-derived raw material using the plant-derived material as a raw material, and recovering or removing the Si source after carbonization. Thereby, a plant-derived Si source used as the first Si source composition of this technology can be obtained.

[0053] 2-1-1-3-1) Plant-derived material (raw material) As plant-derived materials, although not particularly limited, for example, cereals such as rice (paddy), wheat (e.g., barley, wheat, rye, etc.), barnyard millet, foxtail millet; gramineous plants such as reed; seaweeds such as wakame, kelp, etc. can be mentioned, but it is not limited to these, and in addition, for example, vascular plants, ferns, mosses, algae, seaweeds growing on land, etc. can also be mentioned. Among these, gramineous plants are preferred from the viewpoint of effective utilization, and more preferably, rice (paddy) and / or wheat, and even more preferably, rice (paddy).

[0054] The part used as the raw material is not particularly limited, but the outer skin (so-called husk) and / or the stem, etc. are preferred from the viewpoints of effective utilization and manufacturing energy. More specifically, rice husks, straw, reed, and stem wakame are preferred. One or more selected from the group consisting of these materials can be used. It is known that the outer skin of rice and wheat (so-called husk) (more preferably rice husks) generally contains about 10 to 30% by mass of silica (4 to 15% by mass of silicon). Also, the shape and form of the plant-derived material are not particularly limited. For example, it may be rice husks or straw themselves, or it may be a dried product. Furthermore, in the processing of food and beverages such as beer and spirits, those subjected to various treatments such as fermentation treatment, roasting treatment, extraction treatment, etc. can also be used. More preferably, from the viewpoint of resource recycling of industrial waste, it is preferable to use rice husks, straw, and the outer skin of wheat, etc. after the removal of the outer skin such as dehusking and wheat milling. These processed straw and rice husks can be obtained in large quantities and easily from, for example, agricultural cooperatives, liquor manufacturing companies, and food companies.

[0055] Also, the silicon content in the plant-derived raw material is not particularly limited, but preferably 4% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and even more preferably 9% by mass or more. Also, the upper limit value may be, for example, 15% by mass, 14% by mass, or 13% by mass or less. Also, it is preferable that silicon is contained in the plant-derived raw material as an amorphous silica component. Generally, the silicon content in rice husks is said to be about 9% by mass, and the silicon content in straw is about 7% by mass. Also, in rice husks and straw, silicon is contained as an amorphous silica component, and the silicon content in the rice husks used in the following examples was about 9% by mass.

[0056] 2-1-1-3-2) Carbonization treatment The carbonization treatment is not particularly limited, and it is preferable to obtain a porous carbon material as the main product from a plant-derived material. As the carbonization treatment, preferably, the plant-derived material is carbonized at 400°C to 1400°C, and as the temperature of the carbonization treatment, more preferably 450°C or higher, and even more preferably 500°C to 800°C. In the present technology, the material before performing the Si source removal (recovery) treatment (for example, acid or alkali treatment, etc.) after the carbonization treatment is also referred to as a 'porous carbon material precursor' or a 'carbonaceous substance'.

[0057] Also, the plant-derived raw material may be pulverized to a desired particle size, classified, or washed in advance, as desired, before the carbonization treatment described below.

[0058] Here, carbonization treatment generally means converting an organic substance (for example, a plant-derived material) into a carbonaceous substance by heat treatment (see, for example, JIS M0104-1984). As the atmosphere for the carbonization treatment, an atmosphere with oxygen blocked can be mentioned. Specifically, an atmosphere in which the plant-derived material is in a kind of steamed state, such as under a vacuum atmosphere or an inert gas atmosphere, can be mentioned. As the atmosphere, an inert gas is preferable, and the inert gas is not particularly limited, but for example, nitrogen gas and / or argon gas can be used, and more preferably nitrogen gas.

[0059] The heating rate until reaching the carbonization temperature is not particularly limited. However, under the above-described atmosphere, as the lower limit value, preferably it is 1 °C / min or more, more preferably 3 °C / min or more, still more preferably 4 °C / min or more, and even more preferably 5 °C / min or more. Also, under the above-described atmosphere, as the upper limit value, preferably it is 10 °C / min or less, more preferably 8 °C / min or less, still more preferably 6 °C / min or less. As the range of the suitable heating rate, 4 - 6 °C / min is preferable under the above-described atmosphere. In the case of manufacturing carbonized products for activated carbon raw materials as generally carried out worldwide, if the temperature of the carbonization treatment can be controlled without controlling the heating rate in the present technology, controlling the heating rate is not necessary.

[0060] Also, the upper limit of the carbonization treatment time is not particularly limited, but preferably it is 10 hours or less, more preferably 7 hours or less. Also, the lower limit of the carbonization treatment time is preferably set to the time when the plant-derived material is surely carbonized, and examples include 0.5 hours or more or 1 hour or more.

[0061] The obtained porous carbon material precursor or porous carbon material may be pulverized to a desired particle size or classified as desired. Alternatively, the porous carbon material after the activation treatment may be pulverized to a desired particle size or classified as desired.

[0062] 2-1-1-3-3) Pretreatment of the carbonization treatment (pre-carbonization treatment) More preferably, although depending on the plant-derived material to be used, it is to perform a pretreatment before carbonizing the plant-derived material. Examples include preliminary heat treatment, pretreatment with a solvent, and the like. As the preliminary heat treatment, it is preferable to perform a heat treatment (pre-carbonization treatment) on the plant-derived material in a state where oxygen is blocked at a temperature lower than the temperature for the carbonization treatment (for example, 400 °C - 700 °C). As a result, it is possible to extract tar components that would be generated during the carbonization process, thereby reducing or removing the tar components that would be generated during the carbonization process. Thereby, the tar components in the plant-derived Si source (for example, recovered materials, by-products, etc.) can be reduced or removed. The "state where oxygen is blocked" in the preliminary carbonization treatment can adopt the atmosphere of the above-mentioned "carbonization treatment", and examples thereof include nitrogen gas and argon gas. In addition, examples of materials for which it is preferable to perform heat treatment in an inert gas atmosphere include plants that generate a large amount of wood vinegar (tar and light oil components).

[0063] Also, before the preliminary carbonization treatment, it can be appropriately changed depending on the plant-derived material used, but it is preferable to perform a treatment for preliminarily reducing the mineral components and moisture contained in the plant-derived material, and a treatment for preventing the generation of abnormal odors during the carbonization process. For example, it is preferable to perform pretreatment of the plant-derived material with alcohol (for example, alcohols having 1 to 3 carbon atoms such as methyl alcohol, ethyl alcohol, and isopropyl alcohol). By this pretreatment with alcohol, reduction of mineral components and moisture and prevention of the generation of abnormal odors can be achieved. Examples of this pretreatment with alcohol include dipping and spraying, but dipping is preferable. In addition, examples of materials for which it is preferable to perform pretreatment with alcohol include seaweeds containing a large amount of iodine and various minerals.

[0064] 2-1-1-3-4) Si source removal treatment (Si source recovery treatment) As the Si source removal treatment (Si source recovery treatment) in the present technology, although not particularly limited, for example, acid, alkali treatment, etc. can be mentioned. By this treatment for removing (recovering) the Si source, the Si source can be removed (recovered) from the plant-derived raw material (porous carbon material precursor, carbonaceous substance, or porous material) after carbonization treatment. Thereby, the plant-derived Si source can be recovered, and a recovered product (plant-derived Si source) containing the Si source can be obtained by this recovery. In the present technology, this plant-derived Si source (for example, a recovered product containing the Si source, by-products, etc.) can be used as a composition containing the first Si source. Here, as the Si source, although not particularly limited as long as it is a silicon component, for example, silicon oxides (so-called silica) such as silicon dioxide, silicon oxide, silicon oxide salts, etc. can be mentioned.

[0065] Examples of the Si source removal treatment (Si source recovery treatment) include treatment with acid or alkali (preferably alkali treatment), dry etching method, high-temperature firing treatment, etc. It is preferable that the recovered product containing the Si source of the present technology is obtained by recovering the treated waste liquid, the waste liquid after washing, etc. generated during this Si source removal treatment (Si source recovery treatment). Among these, the acid or alkali treatment liquid of the porous carbon material precursor is preferable. Also, the recovered product containing the Si source of the present technology can also be obtained by further subjecting the treated product after carbonization treatment to high-temperature firing treatment. Moreover, it is preferable from the viewpoint of obtaining the inorganic porous material of the present technology that the pH of the solution is adjusted to be alkaline for the recovered product containing the Si source of the present technology. More preferably, the pH is 8 or more, still more preferably 11 or more, and even more preferably 13 or more. At this time, as the alkali for adjusting the alkalinity, the alkali for <alkali treatment> described later can be adopted, and among these, sodium hydroxide is preferably used.

[0066] Regarding the preferable acid or alkali treatment as the Si source removal (recovery) treatment, it will be described below. Specifically, by performing acid or alkali treatment after carbonization treatment, the silicon component in the plant-derived material can be removed (or recovered) from the porous carbon material precursor or the porous carbon material. Also, based on the dry etching method, the silicon component in the plant-derived material after carbonization may be removed. Further, for example, by immersing in inorganic acids such as hydrochloric acid, nitric acid, and sulfuric acid, the mineral components contained in the plant-derived material after carbonization can be removed and included in the recovered product containing the Si source.

[0067] A more suitable Si source removal (recovery) treatment includes treating the porous carbon material precursor with an acid or an alkali. More specific treatment methods include, for example, a method of immersing the porous carbon material precursor in an aqueous solution of an acid or an alkali, and a method of reacting the porous carbon material precursor with an acid or an alkali in the gas phase. As a more suitable Si source recovery treatment, alkali treatment is preferred.

[0068] 2-1-1-3-4-1) Alkali treatment When performing the removal treatment (Si source recovery treatment) of the Si source with an alkali (base), examples of the alkali to be used include hydroxides, oxides, etc. Among these, preferably, it is a hydroxide that is easy to handle. Further, examples of the hydroxide include alkali metal hydroxides, alkaline earth metal hydroxides, etc. Among these, preferably, from the viewpoint of obtaining a Si source composition that is a raw material for an inorganic porous material, it is an alkali metal hydroxide (for example, sodium hydroxide, potassium hydroxide, etc.), and more preferably sodium hydroxide.

[0069] In addition, the temperature of the alkali treatment is not particularly limited. However, as a preferable lower limit value, it is preferably 0°C or higher, more preferably 20°C or higher, still more preferably 50°C or higher, even more preferably 60°C or higher, and even more preferably 70°C or higher. As a preferable upper limit value, it is preferably 300°C or lower, more preferably 130°C or lower, still more preferably 120°C or lower, even more preferably 110°C or lower. As a preferable numerical range, it is preferably 0 to 300°C, more preferably 20 to 120°C, and even more preferably 70 to 110°C. In addition, the time of the alkali treatment is not particularly limited. However, as a preferable lower limit value, it is preferably 3 hours or longer, more preferably 6 hours or longer, still more preferably 8 hours or longer, even more preferably 12 hours or longer, and even more preferably 18 hours or longer. Also, the preferable upper limit value is not particularly limited, and long-time treatment may be performed. However, from the viewpoint of working efficiency, it is preferably 48 hours or shorter, more preferably 30 hours or shorter, still more preferably 18 hours or shorter, and even more preferably 15 hours or shorter. If necessary, it is preferable to additionally perform the treatment for 0.5 to 2 hours (100 to 120°C) in a pressure-resistant container. In the alkali treatment, it is preferable to use an alkali solution from the viewpoint of working efficiency, and an aqueous solution state is more preferable. The pH during this treatment may be in the alkali region, but it is preferably 9 or higher, more preferably 10 or higher, still more preferably 11 or higher, even more preferably 12 or higher, and even more preferably 13 or higher. In addition, the concentration of the alkali metal in the aqueous solution used for the alkali treatment is not particularly limited. However, from the viewpoint of handling, it is preferably 5 to 50% by mass.

[0070] 2-1-1-3-4-1a) Alkali extraction As the first Si source composition, it is preferable to use a recovered product containing a Si source obtained by an alkali extraction treatment performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si after carbonizing a plant-derived material from the viewpoint of improving the production efficiency of the inorganic porous material (preferably, LTA type, CHA type) of the present technology. (Hereinafter, it is also referred to as "alkali extract").

[0071] The inventors set the molar ratio (theoretical ratio) of NaOH / Si in the alkali extract and considered treating the processed product after carbonization of the plant-derived material (hereinafter also referred to as "carbonized processed product") by alkali extraction adjusted to this molar ratio. As a result, by setting the molar ratio (theoretical ratio) of NaOH / Si in this alkali extract and adjusting it to this molar ratio to perform alkali extraction of the Si source composition from the carbonized processed product, the extraction efficiency of the Si source from the carbonized processed product can be improved. By using this alkali extract as the first Si source composition, one or more zeolites selected from LTA-type zeolite, CHA-type zeolite, FAU-type zeolite, etc. can be produced more purely, and it was also found that it is not necessary to use a second Si source composition as a raw material. Further, the inventors found that by using this alkali extraction, it is possible to process a large amount of carbonized processed product, and since the extraction efficiency of the Si source from the carbonized processed product is good, the quality of the porous carbon material obtained from the carbonized processed product can also be further improved.

[0072] Thus, by using the recovered product containing the Si source obtained by alkali extraction as the first Si source composition as a raw material, an inorganic porous material (preferably, LTA-type zeolite, CHA-type zeolite) can be produced better. Further, the recovered product containing the Si source obtained by this alkali extraction can be used to better produce LTA-type zeolite and / or CHA-type zeolite. By using the recovered product containing the Si source obtained by this alkali extraction, a pure phase of LTA-type zeolite and a single phase of CHA-type zeolite can also be produced better.

[0073] Also, for the Si source composition obtained without adjusting the molar ratio (theoretical ratio) of NaOH / Si, it is preferable to adjust the gel composition ratio of the raw material using the second Si source composition. However, the Si source composition obtained by the treatment by alkali extraction performed by adjusting the molar ratio (theoretical ratio) of NaOH / Si has the advantage that it is not necessary to adjust the gel composition ratio of the raw material using the second Si source composition.

[0074] Regarding materials, carbonization treatment, alkali treatment as Si source recovery treatment, etc. in alkali extraction, the description of the above "2-1-1-3-4-1) Alkali treatment" can be appropriately adopted, and more preferable conditions will be described below.

[0075] As a plant-derived material for obtaining a carbonized product used in alkali extraction, preferably a gramineous plant, more preferably the outer skin, stem, and even more preferably the outer skin of rice and / or wheat (so-called husk) are suitable. The suitable temperature for alkali extraction is not particularly limited, but as its suitable lower limit value, preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher. Also, as its suitable upper limit value, preferably 130°C or lower, more preferably 120°C or lower, even more preferably 110°C or lower, even more preferably 100°C or lower, even more preferably 90°C or lower. As the suitable numerical range, preferably 50 to 120°C, even more preferably 60 to 100°C.

[0076] The suitable time for alkali extraction is not particularly limited, but as its suitable lower limit value, preferably 2 hours or more, even more preferably 6 hours or more, more preferably 8 hours or more, more preferably 12 hours or more, more preferably 18 hours or more. Also, its suitable upper limit is not particularly limited and long-time treatment may be performed, but from the perspective of working efficiency, preferably 60 hours or less, more preferably 48 hours or less, even more preferably 36 hours or less, more preferably 30 hours or less, more preferably 28 hours or less. As the suitable numerical range, preferably 2 to 36 hours, more preferably 6 hours to 30 hours. In addition, if necessary, 0.5 to 2 hours (100 to 120°C) may be added in a pressure-resistant container.

[0077] As more preferable alkali extraction, preferably 50 to 130°C and 8 to 48 hours, even more preferably 60 to 110°C and 18 to 30 hours. When performing alkali treatment, for 1 part by mass of the carbonized product, the water used for alkali treatment is preferably 1 to 10 parts by mass, more preferably 3 to 8 parts by mass. After the alkali extraction, post-treatment such as filtration may be performed using a filtration device or the like configured to remove suspended matter, insoluble matter, etc. from the recovered material by filtration or the like. As a result, suspended matter, insoluble matter, etc. during the recovery can be removed, and thus it is also possible to improve the quality of the inorganic porous material manufactured thereafter. For filtration, known industrial filtration can be used.

[0078] In the alkali extraction of the present technology, the molar ratio (theoretical ratio) of NaOH / Si, from the viewpoints of Si extraction efficiency and manufacturing the desired zeolite, has a preferable lower limit value, preferably 0.1 or more, more preferably 0.3 or more. Also, as its preferable upper limit value, although not particularly limited, for example, 4 or less, 3.5 or less, or 3 or less can be mentioned. A preferable numerical range of the molar ratio (theoretical ratio) of NaOH / Si is preferably 0.1 to 4. By appropriately adjusting within this range, it is also possible to obtain a first Si source composition suitable for any zeolite. Furthermore, in the alkali extraction of the present technology, for example, by adjusting the molar ratio (theoretical ratio) of NaOH / Si, the Si extraction efficiency becomes as high as about 80% or more from a molar ratio of 0.5 or more, and the Si extraction efficiency can be made 100% at a molar ratio of 1.0 to 2.0. Therefore, it is also preferable from the viewpoint of improving the mass productivity of the porous material. Also, by using the recovered material (preferably the extract) containing the Si source obtained by the treatment by alkali extraction performed by appropriately adjusting this molar ratio (theoretical ratio) of NaOH / Si, it is possible to efficiently manufacture LTA-type zeolite, CHA-type zeolite, FAU-type zeolite, etc. with better quality.

[0079] Furthermore, when manufacturing LTA-type zeolite, it is preferable to adjust the molar ratio (theoretical ratio) of NaOH / Si to preferably 2 to 4, more preferably 3 to 4, even more preferably 2.5 to 3.5. It is more preferable to use at least the first Si source composition, an Al source, and appropriately water as raw materials to obtain a raw material with a gel composition ratio suitable for LTA-type zeolite. At this time, it is even more preferable to add the Al source so that the Si / Al composition ratio (mass / mass) becomes 1.0 to 2.0.

[0080] Furthermore, when producing FAU-type zeolite, it is preferable to adjust the molar ratio of NaOH / Si (theoretical ratio) to preferably 2 to 4, more preferably 3 to 4, and even more preferably 2.5 to 3.5. It is more preferable to use at least the first Si source composition, an Al source, and appropriately water as raw materials to obtain a raw material with a gel composition ratio suitable for FAU-type zeolite. At this time, it is even more preferable to add an Al source so that the Si / Al composition ratio (mass / mass) becomes 0.1 to 1.0.

[0081] Furthermore, when producing CHA-type zeolite, it is preferable to adjust the molar ratio of NaOH / Si (theoretical ratio) to preferably 0.1 to 1.0, more preferably 0.2 to 0.9, and even more preferably 0.3 to 0.8. It is more preferable to use at least the first Si source composition, an Al source, and an alkali metal source (preferably Na and K) as raw materials to obtain a raw material with a gel composition ratio suitable for CHA-type zeolite.

[0082] The "Si extraction efficiency" in the alkali extraction of this technology is a value that can be obtained by [Si measured concentration (mol / L) of plant-derived material ash / Si theoretical concentration (mol / L) of plant-derived material ash] × 100 (%). For example, in the case of rice husks, it can be obtained by [Si measured concentration (mol / L) of rice husk ash / Si theoretical concentration of rice husk ash being 1.20 mol / L] × 100 (%).

[0083] As an example, the amount of Si in the "molar ratio of NaOH / Si" in alkali extraction can be calculated by the weight residue by TG (thermogravimetric analysis) (for example, the weight residue of rice husks is 42%) × the Si content rate of the material ash (for example, the Si content rate of rice husk ash is 90%). However, this weight residue and the Si content rate of rice husk ash are not particularly limited to rice husks, and may be the weight residue and the Si content rate of material ash of other plant-derived materials. Also, the weight residue by TG and the Si content rate of the ash may be the average value obtained by extracting a plurality of samples from one lot of plant-derived materials. The Si measurement concentration (mol / L) can be measured using inductively coupled plasma atomic emission spectrometry (ICP-AES). The Na measurement concentration (mol / L) can be measured using atomic absorption spectrometry (AAS).

[0084] The recovered product containing the plant-derived Si source obtained by alkali extraction is preferably in a liquid state such as an aqueous solution. The Si measurement concentration (mol / L) of the alkali extract mainly depends on the alkali concentration in the alkali extraction. Its preferred lower limit is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.8 or more, and even more preferably 0.9 or more. Also, its preferred upper limit is not particularly limited, but is preferably 1.3 or less, more preferably 1.2 or less, and still more preferably 1.1 or less.

[0085] The Na measurement concentration (mol / L) of the alkali extract has a preferred lower limit of preferably 0.3 or more, more preferably 0.4 or more, and still more preferably 0.5 or more. Also, its preferred upper limit is preferably 2 or less, more preferably 1.5 or less. When the alkali extract is used for LTA-type zeolite and / or FAU-type zeolite, the Na measurement concentration (mol / L) of the alkali extract has a preferred upper limit of preferably 0.8 mol / L or less, and more preferably in the range of 0.3 to 0.8 mol / L as this numerical range. When the alkali extract is used for CHA-type zeolite, the Na measurement concentration (mol / L) of the alkali extract has a preferred lower limit of preferably 0.7 mol / L or more, more preferably 0.8 mol / L or more, and more preferably in the range of 0.8 to 1.5 mol / L as this numerical range.

[0086] In this alkali extract, when using a Gramineae plant, preferably rice husk as the material, the measured Si concentration in the alkali extract can be easily extracted and recovered within the range of 0.9 to 1.1 mol / L. In alkali extraction, it is desirable to use a Gramineae plant, preferably rice husk as the material. Further, regardless of the amount of hydroxide used in alkali extraction, since the measured Si concentration and extraction efficiency are similar, it is desirable from the viewpoint of being able to provide a recovered product with stable quality.

[0087] Also, in alkali extraction, the molar ratio (theoretical ratio) of NaOH / Si, from the viewpoint of CHA-type zeolite production, as a preferable lower limit, is preferably 0.1 or more, more preferably 0.3 or more. As its preferable upper limit, it is preferably 1.0 or less, more preferably 0.8 or less. As a preferable numerical range, it is more preferably 0.3 to 0.8. By using the first Si source composition obtained by alkali extraction so that the molar ratio of NaOH / Si is achieved after carbonization treatment, CHA-type zeolite can be easily produced without using a second Si source composition, and moreover, a single-phase CHA-type zeolite can be produced without an OSDA. Also, CHA-type zeolite can be obtained by drying without firing after drying. Mass production of CHA-type zeolite is also possible. Therefore, by this technology, a first Si source composition for producing CHA-type zeolite or for use in producing CHA-type zeolite can be provided, and also a composition for producing CHA-type zeolite containing the first Si source composition and a method for producing CHA-type zeolite using the first Si source composition can be provided.

[0088] Also, in the alkali extraction, the molar ratio of NaOH / Si (theoretical ratio), from the viewpoint of manufacturing LTA-type zeolite and / or FAU-type zeolite, as a preferable lower limit value, is preferably 1.0 or more, more preferably 2.0 or more, still more preferably 2.5 or more, and even more preferably 3.0 or more. Also, as its preferable upper limit value, it is preferably 4.0 or less, more preferably 3.5 or less, and as a preferable numerical range, it is more preferably 2.5 to 3.5. After the carbonization treatment, by using the first Si source composition obtained by alkali extraction so as to have this molar ratio of NaOH / Si (theoretical ratio), even without using the second Si source composition, LTA-type zeolite can be easily manufactured, and moreover, single-phase LTA-type zeolite can be manufactured. Also, LTA-type zeolite can be obtained by drying without firing after drying. Mass production of LTA-type zeolite is also possible. Therefore, by this technology, the first Si source composition for manufacturing LTA-type zeolite or used for manufacturing LTA-type zeolite can be provided, and also, the composition for manufacturing LTA-type zeolite containing the first Si source composition and the method for manufacturing LTA-type zeolite using the first Si source composition can be provided.

[0089] In addition, when removing (or recovering) the silicon component (for example, silicon dioxide) contained in the porous carbon material precursor with an aqueous sodium hydroxide solution, by heating the aqueous sodium hydroxide solution, silicon dioxide reacts as shown in the following chemical formula (A) and is removed as sodium silicate (Na2SiO3), and a porous carbon material can be obtained. Also, when treating by reacting sodium hydroxide in the gas phase, by heating the solid of sodium hydroxide, it reacts as shown in the chemical formula (A) and is removed as sodium silicate (Na2SiO3), and a porous carbon material can be obtained. Furthermore, it is preferable to wash and dry the alkali-treated porous carbon material.

[0090] SiO2 + 2NaOH → Na2SiO3 + H2O (A)

[0091] In addition, as the solution used for washing, although not particularly limited, using water is preferable because the Si source (for example, recovered materials, by-products, etc.) recovered in the production of the porous material of the present technology is more easily utilized effectively in an aqueous solution. If necessary, examples of the aqueous solvent include water, alcohol, acetone, etc., and it is also possible to use one or more selected from the group consisting of these. As the alcohol, the alcohol used in the above-mentioned "pretreatment" can be adopted, and ethyl alcohol is preferable.

[0092] In this way, in the process of the alkali treatment for Si source removal (recovery), alkali treatment waste liquids (such as waste liquids after alkali treatment and waste liquids after washing) are generated, so these waste liquids can be recovered to obtain a recovered material containing the Si source of the present technology. In the present technology, it is preferable to use this recovered material containing the plant-derived Si source as the first Si source composition. Also, as this recovered material containing the plant-derived Si source, it is preferable to use a waste liquid containing plant-derived silica (hereinafter also referred to as "silica waste liquid") in the production of the porous material of the present technology.

[0093] 2-1-1-3-4-2) Acid treatment When performing the treatment for removing the Si source with an acid, the acid used is not particularly limited, and examples thereof include fluorine compounds showing acidity such as hydrogen fluoride, hydrofluoric acid, ammonium fluoride, calcium fluoride, and sodium fluoride, and one or more selected from the group consisting of these can be used.

[0094] When using a fluorine compound, the amount of fluorine element should be four times that of silicon element in the silicon component contained in the porous carbon material precursor, and the concentration of the aqueous solution of the fluorine compound is preferably 10% by mass or more. When removing the silicon component (for example, silicon dioxide) contained in the porous carbon material precursor with hydrofluoric acid, silicon dioxide reacts with hydrofluoric acid as shown in Chemical Formula (B) or Chemical Formula (C), and is removed as hexafluorosilicic acid (H2SiF6) or silicon tetrafluoride (SiF4), and a porous carbon material can be obtained. Then, it is preferable to wash and dry the porous carbon material thereafter. For washing, the washing procedure of <alkali treatment> described above can be adopted. When treating with an acid, for example, by treating with an inorganic acid such as hydrochloric acid, nitric acid, or sulfuric acid, it is possible to remove the mineral components contained in the porous carbon material precursor.

[0095] In this way, the acid treatment waste liquid (waste liquid after acid treatment or waste liquid after washing) generated in the process of acid treatment for Si source removal (recovery) can be recovered to obtain a recovered product containing the Si source of the present technology, and it is preferable to use this recovered product containing the plant-derived Si source as the first Si source composition. In addition, from the viewpoint of production efficiency, it is preferable to add an alkali agent to the acid treatment waste liquid to make it in the same alkali region as the above-described alkali treatment. At this time, the same alkali agent as the above-described alkali treatment (for example, hydroxide) can be used as the alkali agent for making it in the alkali region, and sodium hydroxide is preferable.

[0096] SiO2 + 6HF → H2SiF6 + 2H2O (B) SiO2 + 4HF → SiF4 + 2H2O (C)

[0097] 2-1-2. Composition Containing the First Si Source As described above, a plant-derived Si source (for example, a recovered material containing plant-derived Si) can be obtained from a plant-derived material. In the present technology, it is preferable from the viewpoints of effective utilization and cost to use, as a recovered material containing a plant-derived Si source, by-products, waste, etc. obtained when obtaining a porous carbon material as a main product. From the viewpoint of reducing the number of working steps, manufacturing energy, etc., it is preferable that the composition of the obtained composition containing the Si source (for example, a recovered material, a by-product, etc.) is the same as the composition of the first Si source composition described above.

[0098] The recovered material of the plant-derived Si source is preferably used in a liquid state such as an aqueous solution. It can be easily made into a target gel composition by appropriately adding a second Si source composition, an Al source, a Na source, water, etc. to the liquid recovered material. Further, when the recovered material is in a liquid state, there is also an advantage that insoluble substances (more preferably water-insoluble substances) contained therein can be easily removed by removal means such as filtration and centrifugation described later. For this reason, a liquid recovered material is also preferable from the viewpoints of ease of handling, improvement of working efficiency, energy efficiency, etc. in the production of the porous material of the present technology.

[0099] Note that the recovered material of the plant-derived Si source is not limited to a liquid state such as an aqueous solution, and may be in a solid or semi-solid state such as powder, frozen, crushed material, etc. as necessary from the viewpoints of storage, transportation, etc. Further, the recovered material containing the Si source may be diluted with an aqueous solvent such as water or concentrated by evaporation of water or the like as necessary.

[0100] Furthermore, the recovered material of the plant-derived Si source can be subjected to known production methods such as separation as necessary to remove impurities such as water-insoluble substances. Removing impurities from the recovered material of the plant-derived Si source is preferable from the viewpoint of easily obtaining a homogeneous target porous material. For example, filtration method, precipitation method, centrifugation method, ion exchange method, electrodialysis method, isoelectric point method, crystallization method, etc. can be mentioned, and one or more selected from the group consisting of these can be used.

[0101] In addition, as the separation supplies for filtration separation, it is preferable to use an acid-resistant or alkali-resistant membrane. For example, filter paper (e.g., paper-made, glass-made); membranes such as nylon membrane, polypropylene membrane, polytetrafluoroethylene membrane, polyethersulfone membrane, polyvinylidene fluoride membrane, glass fiber membrane; filters, etc. can be mentioned, but it is not limited thereto. It is preferable to use separation supplies that can remove insoluble substances of preferably 10 μm or more, more preferably 1.0 μm or more from the recovered product of the plant-derived Si source. For example, separation supplies (e.g., filters, etc.) with a pore diameter of 10 μm or less or 1.0 μm or less are preferable.

[0102] 2-1-3. Porous carbon material after Si source removal (recovery) treatment In addition, as a preferable porous carbon material, the value of the specific surface area by the nitrogen BET method is 10 m 2 / gram or more, the silicon (Si) content is 1 wt% or less, and the pore volume by the BJH method and the MP method is 0.1 cm 3 / gram or more. It is preferable to have such a configuration. Also, it is preferable that the magnesium (Mg) content in the porous carbon material is 0.01 wt% or more and 3 wt% or less, the potassium (K) content is 0.01 wt% or more and 3 wt% or less, and the calcium (Ca) content is 0.05 wt% or more and 3 wt% or less.

[0103] 2-1-4. Second Si source composition The second Si source composition is a composition containing a second Si source. The second Si source is not particularly limited, and various known substances can be used. As the second Si source, for example, fumed silica, colloidal silica, amorphous silica, sodium silicate, methyl silicate, ethyl silicate, silicon alkoxides such as trimethylethoxysilane, tetraethyl orthosilicate (TEOS), aluminosilicate gel, etc. can be used. Preferably, they are fumed silica, colloidal silica, amorphous silica, sodium silicate, methyl silicate, ethyl silicate, silicon alkoxides, aluminosilicate gel. One or more selected from the group consisting of these can be used.

[0104] The origin of the second Si source is not particularly limited, and examples include mineral origin, microorganism origin (such as diatoms and genetically engineered microorganisms), plant origin, etc. Any of these may be used, and one or more selected from the group consisting of these can be used. Also, the second Si source composition derived from these can be obtained by known production methods. Among these, the Si source derived from plants (preferably having a Si content of 4% by mass or more) is preferable from the viewpoints of effective utilization and production energy.

[0105] Furthermore, from the viewpoints of effective utilization and production energy, it is more preferable to employ the plant used for the first Si source when producing the second Si source composition. Among these, gramineous plants are suitable, and more preferably, they are rice (paddy) and / or wheat. As the part of the plant, the husk and / or the stem are suitable. Since the husk and the stem can be obtained as plant-derived waste or by-products containing a large amount of Si during threshing, etc., they are more suitable from the viewpoints of effective utilization and production energy. Among these, rice husk and / or straw are also suitable from the viewpoints of easily manufacturing various zeolites and production energy.

[0106] When the second Si source composition is produced from plant-derived by-products, it is preferable that the second Si source composition has a composition different from that of the first Si source composition from the viewpoints of easily manufacturing various zeolites and production energy. In addition, the second Si source composition is suitable from the viewpoints of easily producing various zeolites from plant-derived ash obtained by ashing plants and manufacturing energy. This plant-derived ash, which is the second Si source composition, may be used as the first Si source composition. In the case of plant-derived ash, there are advantages such as higher reactivity of amorphous SiO2 than the recovered product by alkali treatment or the like, freedom in the range of the synthesis gel, ease of extraction operability, storage stability, and transportability. On the other hand, there are also disadvantages such as increased energy consumption, easy residual of impurities such as inorganic salts, and inability to utilize porous carbon materials. Since the treated material that has been conventionally regarded as waste can be recovered as an alkali-treated product by this technology and this recovered product can be converted into a high-functional material, the recovered product of this technology is more desirable than the plant-derived ash obtained by high-temperature firing.

[0107] The composition in the second Si source composition preferably contains at least silicon (Si), aluminum (Al), and an alkali metal (for example, Na or K). The form of the composition is not particularly limited, and examples include liquids (for example, aqueous solutions) and solids (for example, powders). When the first Si source composition is a liquid such as an aqueous solution, the second Si composition may be a solid, and when the first Si source composition is a solid, it is preferable that the second Si composition is a liquid. The alkali metal is not particularly limited, and examples include sodium, potassium, lithium, etc., and it is preferable to use one or more selected from the group thereof, and more preferably sodium.

[0108] The Si content in the second Si source composition is not particularly limited, but its preferable lower limit is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 85% by mass or more, and even more preferably 90% by mass or more. Also, its preferable upper limit is preferably 98% by mass or less, more preferably 95% by mass or less, still more preferably 93% by mass or less, and even more preferably 92% by mass or less. As a preferable numerical range, it is preferably 90 to 92% by mass.

[0109] The potassium content in the second Si source composition is not particularly limited, but its preferable lower limit is preferably 2% by mass or more, more preferably 3% by mass or more, still more preferably 4% by mass or more, and even more preferably 4.5% by mass or more. Also, its preferable upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, still more preferably 6% by mass or less, even more preferably 5.5% by mass or less, and even more preferably 5.3% by mass or less. As a preferable numerical range, it is preferably 4.5 to 5.5% by mass.

[0110] The calcium content in the second Si source composition is not particularly limited, but its preferable lower limit is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 0.8% by mass or more. Also, its preferable upper limit is preferably 1.6% by mass or less, more preferably 1.4% by mass or less, still more preferably 1.2% by mass or less, and even more preferably 1.1% by mass or less. As a preferable numerical range, it is preferably 0.9 to 1.2% by mass.

[0111] The iron content in the second Si source composition is not particularly limited, but its preferable lower limit is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more. Also, its preferable upper limit is preferably 1.0% by mass or less, more preferably 0.8% by mass or less, still more preferably 0.6% by mass or less, and even more preferably 0.55% by mass or less. As a preferable numerical range, it is preferably 0.4 to 0.6% by mass.

[0112] The phosphorus content in the second Si source composition is not particularly limited, but its preferable lower limit is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more. Also, its preferable upper limit is preferably 1.0% by mass or less, more preferably 0.8% by mass or less, still more preferably 0.6% by mass or less, and even more preferably 0.55% by mass or less. As a preferable numerical range, it is preferably 0.4 to 0.6% by mass.

[0113] The content of other metals in the second Si source composition other than the above Si, K, Ca, Fe, and P is not particularly limited, but the preferable upper limit thereof is preferably 1.8% by mass or less, more preferably 1.7% by mass or less, and still more preferably 1.5% by mass or less. In addition, the content of Al in the second Si source composition is not particularly limited, but the preferable upper limit thereof is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and still more preferably 0.5% by mass or less.

[0114] 2-1-4-1. Method for producing a second Si source composition derived from plants The method for producing the second Si source composition used in the present technology is not particularly limited, and it can be produced by a known production method. Among these, the second Si source composition derived from plants can also effectively utilize by-products and waste generated in large quantities, and can reduce the production energy compared with that derived from minerals.

[0115] It is more preferable that the second Si source composition in the present technology is a processed product obtained by decarbonizing a plant-derived raw material. This processed product is preferably plant-derived ash. As the decarbonization treatment, it is preferable to perform a heat treatment for pyrolysis. Poaceae plants are preferable as the material, among which rice or wheat is more preferable, and their husks and / or stems are more preferable, and among these, rice husks are more preferable.

[0116] As the atmosphere for the decarbonization treatment, a gas containing oxygen is preferable, and air is more preferable from the viewpoint of cost. The flow rate of the atmosphere is not particularly limited, but is preferably 50 to 500 mL / min, more preferably 100 to 400 mL / min, and still more preferably 100 to 300 mL / min.

[0117] The heating temperature for decarburization treatment is not particularly limited, but its preferred lower limit is preferably 350 °C or higher, more preferably 400 °C or higher, still more preferably 450 °C or higher. Also, its preferred upper limit is preferably 900 °C or lower, more preferably 800 °C or lower, still more preferably 700 °C or lower, even more preferably 650 °C or lower, and more preferably 600 °C or lower. The heating time for decarburization treatment is not particularly limited, but its preferred lower limit is preferably 3 hours or longer, more preferably 4 hours or longer, more preferably 5 hours or longer, more preferably 7 hours or longer, and more preferably 9 hours or longer. Also, its preferred upper limit is preferably 24 hours or shorter, more preferably 18 hours or shorter, still more preferably 15 hours or shorter, even more preferably 13 hours or shorter, more preferably 11 hours or shorter, and more preferably 10 hours or shorter. Preferred conditions for the heating temperature and heating time of the decarburization treatment are preferably 450 to 600 °C and 7 to 11 hours.

[0118] 2-1-5. Al source The Al source is not particularly limited and may be an Al source generally used in the production of inorganic porous materials (preferably silicate-based porous materials), and various known substances can be used. Examples of the Al source include inorganic aluminum compounds such as aluminum nitrate (Al(NO3)3), aluminum hydroxide, aluminum sulfate, aluminum oxide, sodium aluminate, and hydrates thereof; and organic aluminum compounds such as aluminum acetate and aluminum alkoxide. Examples of sodium aluminate include hydroxy complexes such as sodium aluminate dioxide (NaAlO2) and sodium tetrahydroxy aluminate (Na[Al(OH)4]). Examples of aluminum alkoxide include aluminum alcoholates such as aluminum diisopropylate monosec-butyrate, aluminum sec-butyrate, aluminum isopropylate, and aluminum ethoxide. As the Al source, one or more selected from the group consisting of these may be used. Among these, aluminum nitrate (Al(NO3)3) and / or sodium aluminate (NaAlO2) are preferred.

[0119] In the method for producing the porous material (preferably zeolite) of the present technology, the amount of aluminum in the raw material can be appropriately changed depending on the target inorganic porous material (preferably zeolite). The amount of aluminum in the raw material is not particularly limited, but in terms of the molar ratio to 1 mol of silicon (Si) in the raw material, its preferred lower limit is preferably 0.01 or more, more preferably 0.05 or more, and its preferred upper limit is preferably 10 or less, more preferably 5 or less, still more preferably 3 or less, and even more preferably 2 or less, and preferably 0.01 to 10, more preferably 0.05 to 3, and still more preferably 0.05 to 2.

[0120] For example, in the case of the MFI type, the amount of aluminum in the raw material, in terms of the molar ratio to 1 mol of silicon (Si) in the raw material, its preferred lower limit is preferably 0.001 or more, more preferably 0.05 or more, and still more preferably 0.01 or more, and its preferred upper limit is preferably 1.0 or less, more preferably 0.5 or less, still more preferably 0.2 or less, and even more preferably 0.1 or less. For example, in the case of mordenite (MOR), the amount of aluminum in the raw material, in terms of the molar ratio to 1 mol of silicon (Si) in the raw material, its preferred lower limit is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.08 or more, and its preferred upper limit is preferably 1.0 or less, more preferably 0.5 or less, still more preferably 0.3 or less, and even more preferably 0.2 or less.

[0121] Further, for example, in the case of the LTA type, the amount of aluminum in the raw material is expressed as a molar ratio to 1 mol of silicon (Si) in the raw material. The preferable lower limit thereof is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.25 or more, even more preferably 0.5 or more, even more preferably 1 or more, even more preferably 1.5 or more. The upper limit thereof is preferably 4 or less, more preferably 3 or less, still more preferably 2.5 or less, even more preferably 2 or less, even more preferably 1 or less. As the preferable numerical range, it is preferably 1 to 3, and still more preferably 1.5 to 2.5. Further, for example, in the case of the CHA type, the amount of aluminum in the raw material is expressed as a molar ratio to 1 mol of silicon (Si) in the raw material. The preferable lower limit thereof is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.15 or more. As the preferable upper limit thereof, it is preferably 1.0 or less, more preferably 0.5 or less, still more preferably 0.3 or less, even more preferably 2.5 or less. As the preferable numerical range, it is preferably 0.1 to 0.5, and more preferably 0.15 to 0.3.

[0122] Further, for example, in the case of the FAU type (zeolite X), the amount of aluminum in the raw material is expressed as a molar ratio to 1 mol of silicon (Si) in the raw material. The preferable lower limit thereof is preferably 0.1 or more, more preferably 0.3 or more, still more preferably 0.5 or more. The upper limit thereof is preferably 1.5 or less, more preferably 1.0 or less, still more preferably 0.8 or less. As the preferable numerical range, it is preferably 0.3 to 1.0, and more preferably 0.5 to 0.8.

[0123] 2-1-6. Alkali metal source In the present technology, the alkali metal source may be included in the above-described first Si source composition and / or second Si source composition. Further, it is preferable to use a plant or a recovered product derived from a plant (for example, a by-product) as the raw material of the present technology because these contain an alkali metal source. Further, if necessary, an alkali metal source may be further blended into the raw material of the present technology.

[0124] The alkali metal atoms of the alkali metal source are not particularly limited, and known ones used in the synthesis of inorganic porous materials (preferably silicate porous materials) can be used. As the alkali metal, for example, it is preferable to use at least one or two or more selected from the group consisting of lithium, sodium, potassium, rubidium, and cesium, and it is more preferable to crystallize in the presence of alkali metal ions. Furthermore, the alkali metal ions are preferably at least one of sodium, potassium, and cesium, and more preferably sodium and / or cesium. The inclusion of at least one of these alkali metal atoms facilitates the progress of crystallization and makes it difficult for impurity crystals and the like to form.

[0125] In the method for producing the porous material (preferably zeolite) of the present technology, the amount of alkali metal (preferably sodium) in the raw material can be appropriately changed depending on the target inorganic porous material (preferably zeolite). The amount of alkali metal (preferably sodium) in the raw material is not particularly limited, but in terms of the molar ratio to 1 mol of silicon (Si) in the raw material, its preferable lower limit is preferably 0.01 or more, more preferably 0.1 or more, and its preferable upper limit is preferably 10 or less, and a more preferable numerical range is 0.05 to 10.

[0126] For example, in the case of the MFI type, the amount of alkali metal (preferably sodium) in the raw material, in terms of the molar ratio to 1 mol of silicon (Si) in the raw material, its preferable lower limit is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.08 or more, and its preferable upper limit is preferably 2 or less, more preferably 1 or less, and even more preferably 0.5 or less. Also, for example, in the case of mordenite (MOR), the amount of alkali metal (preferably sodium) in the raw material is in terms of the molar ratio to 1 mol of silicon (Si) in the raw material. The preferred lower limit is preferably 0.01 or more, more preferably 0.05 or more, still more preferably 0.08 or more. Also, the preferred upper limit is preferably 2 or less, more preferably 1 or less, still more preferably 0.5 or less.

[0127] Also, for example, in the case of the LTA type, the amount of alkali metal (preferably sodium) in the raw material is in terms of the molar ratio to 1 mol of silicon (Si) in the raw material. The preferred lower limit is preferably 1 or more, more preferably 1.5 or more, still more preferably 2 or more, even more preferably 2.5 or more. Also, the preferred upper limit is preferably 20 or less, more preferably 15 or less, still more preferably 10 or less, even more preferably 9 or less, even more preferably 8 or less, even more preferably 5 or less, even more preferably 4 or less, even more preferably 3.5 or less. The preferred numerical range is 2 to 4.

[0128] Also, for example, in the case of the CHA type, the amount of alkali metal in the raw material is in terms of the molar ratio to 1 mol of silicon (Si) in the raw material. The preferred lower limit is preferably 0.2 or more, more preferably 0.4 or more, still more preferably 0.6 or more, even more preferably 0.7 or more, even more preferably 0.8 or more. Also, the preferred upper limit is preferably 1.5 or less, more preferably 1.3 or less, still more preferably 1.1 or less, even more preferably 1.0 or less. The preferred numerical range is 0.5 to 1.5. Also, for example, in the case of the CHA type, the amount of sodium in the raw material is in terms of the molar ratio to 1 mol of silicon (Si) in the raw material. The preferred lower limit is preferably 0.2 or more, more preferably 0.4 or more, still more preferably 0.6 or more, even more preferably 0.7 or more. Also, the preferred upper limit is preferably 1.5 or less, more preferably 1.3 or less, still more preferably 1.0 or less, even more preferably 0.9 or less. The preferred numerical range is 0.5 to 1.0. Further, for example, in the case of the CHA type, the amount of potassium in the raw material is in terms of the molar ratio to 1 mol of silicon (Si) in the raw material. The preferable lower limit is preferably 0.01 or more, more preferably 0.05 or more. Also, the preferable upper limit is preferably 0.2 or less, more preferably 0.15 or less. The preferable numerical range is 0.01 to 0.2.

[0129] Further, for example, in the case of the FAU type (zeolite X), the amount of alkali metal (preferably sodium) in the raw material is in terms of the molar ratio to 1 mol of silicon (Si) in the raw material. The preferable lower limit is preferably 1 or more, more preferably 2 or more, still more preferably 2.5 or more. Also, the preferable upper limit is preferably 10 or less, more preferably 8 or less, still more preferably 7 or less, more preferably 6 or less, more preferably 4 or less, more preferably 3.5 or less. The preferable numerical range is 2 to 4.

[0130] 2-1-7. Organic Structure-Directing Agent (OSDA) This technology has the advantage that a porous material containing Si and Al can be produced by using at least the above-mentioned first Si source composition, the second Si source composition, and the Al source as raw materials and appropriately blending water without including an organic structure-directing agent in the raw materials. By using a plant-derived first Si source composition and / or second Si source composition as a raw material as in this technology, it can be produced even without OSDA. In this technology, it is preferable to further use an organic structure-directing agent as a raw material because it is easier to design the crystal structure of the porous material.

[0131] By synthesizing using an organic structure-directing agent, there is an advantage that the ratio of silicon atoms to aluminum atoms in the crystallized zeolite increases and the crystallinity improves. The organic structure-directing agent is not particularly limited, but it is preferable to select one that can form a desired porous material (preferably zeolite). One or more selected from the group consisting of these can be used.

[0132] In the present technology, as a suitable organic structure-directing agent, those suitable for the production of the target inorganic porous material (preferably zeolite) are preferred. Examples of the organic structure-directing agent include tetrapropylammonium bromide (TPABr), tetraethylammonium bromide (TEABr), tetrapropylammonium hydroxide (TPAOH), tetraethylammonium hydroxide (TEAOH), and the like. One or more selected from the group consisting of these can be used. In the method for producing the porous material (preferably zeolite) of the present technology, the amount of the organic structure-directing agent in the raw material is a molar ratio to 1 mol of silicon (Si) in the raw material, and its preferable upper limit value is preferably 0.5 or less, more preferably 0.3 or less, still more preferably 0.2 or less, and even more preferably 0.1 or less. In the examples of the present technology, 0.28 g of tetrapropylammonium hydroxide (TPAOH) was used with respect to 1.0 g of water. Therefore, with respect to 1.0 g of water, the organic structure-directing agent may preferably be used in an amount of about 0.05 to 1.0 g, more preferably about 0.1 to 0.5 g, and this usage amount is not particularly limited and may be free (0 g).

[0133] 2-1-8. Amount of water In the method for producing the porous material (preferably zeolite) of the present technology, the amount of water in the raw material is a molar ratio to 1 mol of silicon (Si) in the raw material from the viewpoint of ease of crystal formation, and its preferable lower limit value is preferably 3 or more, more preferably 5 or more, still more preferably 8 or more, and even more preferably 9 or more. In the present technology, from the viewpoint of suppressing the cost related to waste liquid treatment, the amount of water is a molar ratio to 1 mol of silicon (Si) in the raw material, and its preferable upper limit value is preferably 200 mol or less, more preferably 180 or less, still more preferably 150 or less, and its preferable lower limit value is more preferably 1 or more, still more preferably 10 or more. Also, the amount of water may be adjusted according to the target porous material.

[0134] For example, in the case of the MFI type, the amount of water is the molar ratio to 1 mol of silicon (Si) in the raw material, preferably 5 to 100, more preferably 5 to 50, still more preferably 10 to 25. For example, in the case of mordenite, the amount of water is the molar ratio to 1 mol of silicon (Si) in the raw material, preferably 10 to 40.

[0135] For example, in the case of the LTA type, the amount of water is the molar ratio to 1 mol of silicon (Si) in the raw material. Its preferred upper limit is preferably 10 or more, more preferably 20 or more, still more preferably 30 or more, further preferably 40 or more, more preferably 45 or more, more preferably 50 or more. Also, its preferred lower limit is preferably 300 or less, more preferably 200 or less, still more preferably 100 or less, more preferably 80 or less, more preferably 70 or less, more preferably 65 or less, more preferably 60 or less. The preferred numerical range is preferably 10 to 300, more preferably 20 to 100.

[0136] For example, in the case of the CHA type, the amount of water is the molar ratio to 1 mol of silicon (Si) in the raw material. Its preferred upper limit is preferably 30 or more, more preferably 50 or more, still more preferably 80 or more, more preferably 90 or more. Also, its preferred lower limit is preferably 300 or less, more preferably 200 or less, still more preferably 150 or less, more preferably 130 or less, more preferably 120 or less, more preferably 110 or less. The preferred numerical range is preferably 10 to 200, more preferably 50 to 150.

[0137] For example, in the case of the FAU type (zeolite X), the amount of water is expressed as a molar ratio relative to 1 mol of silicon (Si) in the raw materials. The preferable upper limit thereof is preferably 10 or more, more preferably 20 or more, still more preferably 30 or more, further preferably 40 or more, more preferably 45 or more, and still more preferably 50 or more. Also, the preferable lower limit thereof is preferably 300 or less, more preferably 200 or less, further preferably 100 or less, more preferably 80 or less, more preferably 70 or less, more preferably 65 or less, and still more preferably 60 or less. The preferable numerical range is preferably 10 to 300, and more preferably 20 to 100.

[0138] 2-2. Manufacturing process of the porous material In the manufacturing process of the porous material of the present technology, it is preferable to use at least the above-described first Si source composition and Al source as raw materials, and perform heat treatment so that the raw materials have a specific gel composition (molar ratio) to produce a porous material containing Si and Al. Further, the raw materials may contain a second Si source composition as a raw material, if necessary. Also, the order of blending each raw material is not particularly limited. For example, an Al source or the like may be added to the first Si source composition so as to adjust it to a specific gel composition (molar ratio), or the first Si source composition or the like may be added to an aqueous solution containing an Al source or an alkali metal source or the like. Further, it is preferable to mix each raw material simultaneously or at different times and perform heat treatment. This mixing may be stirred within the range of 10 to 40°C, or may be stirred at room temperature (about 20 to 30°C), and the stirring may be performed for about 1 to 3 hours. It is preferable to use the means or method of heat treatment generally performed for inorganic porous materials for the heat treatment.

[0139] 2-2-1. Gel composition of the raw materials The gel composition of the raw materials is not particularly limited, and the molar ratios of Al, Na, H2O, and the organic structure-directing agent relative to 1 mol of silicon (Si) in the raw materials described above may be appropriately combined.

[0140] The Si / Al composition ratio (mass / mass) in the gel composition of the raw materials is preferably adjusted so as to be the Si / Al composition ratio (mass / mass) of the desired zeolite. The Si / Al composition ratio (mass / mass) in the gel composition of the raw material is not particularly limited, but its preferred lower limit is preferably 0.1 or more, more preferably 0.3 or more, 0.5 or more, or 1 or more, etc. Also, as its preferred upper limit, it is preferably 200 or less, more preferably 150 or less, and even more preferably 120 or less. The preferred numerical range of the Si / Al composition ratio (mass ratio) in the raw material is more preferably 0.1 to 200, and more preferably 0.3 to 120. For example, in the case of the MFI type, the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but it is preferably 0.5 to 130, more preferably 1 to 110, even more preferably 3 to 50, and more preferably 5 to 20. For example, in the case of mordenite (MOR), the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but it is preferably 1 to 100, more preferably 2 to 50, even more preferably 3 to 30, more preferably 5 to 20, and more preferably 5 to 15.

[0141] For example, in the case of the LTA type, the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but its preferred lower limit is preferably 0.1 or more, more preferably 0.2 or more, even more preferably 0.4 or more, more preferably 0.5 or more, and more preferably 0.7 or more. Also, its preferred upper limit is preferably 50 or less, more preferably 20 or less, even more preferably 10 or less, even more preferably 5 or less, more preferably 3 or less, more preferably 2 or less, more preferably 1.5 or less, and more preferably 1 or less. The preferred numerical range is preferably 0.2 to 10, more preferably 0.5 to 5, even more preferably 0.5 to 2, and more preferably 0.8 to 1.0.

[0142] For example, in the case of the CHA type, the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but its preferable lower limit is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.2 or more, even more preferably 0.3 or more, and even more preferably 0.4 or more. Also, its preferable upper limit is preferably 5 or less, more preferably 3 or less, still more preferably 1 or less, and even more preferably 0.8 or less. The preferable numerical range is preferably 0.1 to 1, and more preferably 0.3 to 0.8.

[0143] For example, in the case of the FAU type (zeolite X), the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but it is preferably 0.5 to 5, more preferably 1 to 3, and still more preferably 1 to 2. For example, in the case of the SOD type, the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but it is preferably 0.1 to 100, more preferably 0.5 to 50, and still more preferably 1 to 20. For example, in the case of the GIS type, the Si / Al composition ratio (mass / mass) in the raw material is not particularly limited, but it is preferably 0.1 to 100, more preferably 0.5 to 50, and still more preferably 1 to 20.

[0144] The gel composition (molar ratio) per 1 mol of silicon (Si) in the raw material can be adjusted by adding an Al source or the like to the first Si source composition so as to obtain the gel composition (molar ratio) of the desired zeolite. The gel composition (molar ratio) per 1 mol of silicon (Si) in the raw material is not particularly limited, but Si:Al:Na:H20 is preferably Si 1:Al 0.005 to 2: Na 0.05 to 10:H20 5 to 200. In the case of the MFI type, as a preferable gel composition (molar ratio), Si:Al:Na:H20 is preferably Si 1:Al 0.01 to 1.0:Na 0.05 to 0.5:H20 5 to 30, and more preferably Si 1:Al 0.06 to 0.1:Na 0.1 to 0.4:H20 10 to 25. In the case of mordenite (MOR), as a suitable gel composition (molar ratio), Si:Al:Na:H2O is preferably Si 1:Al 0.01 - 0.5:Na 0.1 - 1.0:H2O 10 - 40, more preferably Si 1:Al 0.05 - 0.15:Na 0.2 - 0.6:H2O 15 - 35.

[0145] In the case of LTA type, as a suitable gel composition (molar ratio), Si:Al:Na:H2O is preferably Si 1:Al 0.5 - 5:Na 1 - 10:H2O 40 - 300, more preferably Si 1:Al 0.5 - 3:Na 1 - 8:H2O 50 - 200, still more preferably Si 1:Al 0.5 - 2:Na 1.5 - 8:H2O 50 - 70.

[0146] In the case of CHA type, as a suitable gel composition (molar ratio), Si:Al:Na:K:H2O, where Si:Al:Na:H2O is preferably Si 1:Al 0.1 - 1:Na 0.6 - 2:K 0.05 - 0.3:H2O 10 - 200, preferably Si 1:Al 0.2 - 0.5:Na 0.8 - 1:K 0.05 - 0.15:H2O 50 - 150.

[0147] In the case of FAU type (zeolite X), as a suitable gel composition (molar ratio), Si:Al:Na:H2O is preferably Si 1:Al 0.1 - 2:Na 1 - 5:H2O 10 - 200, preferably Si 1:Al 0.5 - 1:Na 1 - 4 (preferably 2 - 3):H2O 50 - 150.

[0148] In the case of SOD type, as a suitable gel composition (molar ratio), Si:Al:Na:H2O is preferably Si 1:Al 0.1 - 50:Na 0.1 - 50:H2O 10 - 200, more preferably Si 1:Al 1 - 10:Na 1 - 10:H2O 30 - 100. In the case of the GIS type, as a suitable gel composition (molar ratio), Si:Al:Na:H2O is preferably Si 1:Al 0.1 - 50:Na 0.1 - 50:H2O 10 - 200, more preferably Si 1:Al 1 - 10:Na 0.1 - 10:H2O 30 - 100.

[0149] 2 - 2 - 2. Aging The raw material prepared as described above may be subjected to aging and hydrothermal synthesis, or hydrothermal synthesis may be carried out omitting aging. Before aging and hydrothermal synthesis, the raw material may be stirred at about 10 - 40°C, and the stirring time may be about 1 - 3 hours. In order to obtain an inorganic porous material (preferably zeolite) having high crystallinity, it is preferable to age for a predetermined time under predetermined temperature conditions. Aging while stirring the raw material for a predetermined period is suitable because it can improve the raw material to a more uniform state.

[0150] For example, when producing the MFI type, it is preferable to age the raw material of the first Si source composition (or the raw material obtained by mixing the Si sources of the first Si source composition and, if necessary, the second Si source composition), and after aging, further mix the Al source as a raw material, and then carry out hydrothermal synthesis. Incidentally, after mixing the first Si source composition (appropriately the second Si source composition) and the Al source, aging may be carried out, and at this time, the first Si source composition may be mixed last.

[0151] For example, when producing mordenite (MOR), it is preferable to age the raw material obtained by mixing the Si source of the first Si source composition (or the Si sources of the first Si source composition and the second Si source composition) and the Al source, and then carry out hydrothermal synthesis. Incidentally, after mixing the first Si source composition (appropriately the second Si source composition) and the Al source, aging may be carried out, and at this time, the first Si source composition may be mixed last.

[0152] For example, when manufacturing the LTA type, it is preferable to perform hydrothermal synthesis on the raw material obtained by mixing the Si source of the first Si source composition (or the Si sources of the first Si source composition and the second Si source composition), the Al source, and, as appropriate, the alkali metal source and / or water, and it is preferable to skip the aging process. Note that the first Si source composition, the second Si source composition, the Al source, the alkali metal source as appropriate, and / or water may be aged after mixing, and at this time, the first Si source composition may be mixed last.

[0153] For example, when manufacturing the CHA type, the first Si source composition is mixed into a mixture of the Al source, the alkali metal source (preferably Na and K), and water to adjust the gel composition of the raw material. To the raw material of this gel composition, 10 to 30 parts by mass of CHA type seed crystals are added per 100 parts by mass of the raw material, and after mixing, it is preferable to perform hydrothermal synthesis and it is preferable to skip the aging process. Note that the seed crystals may be those prepared in advance by a known crystallization method from the raw material of this gel composition, or those available on the market.

[0154] The aging temperature is not particularly limited, but its upper limit value is preferably 110°C or lower, more preferably 90°C or lower, still more preferably 80°C or lower, and its lower limit value is preferably 10°C or higher, more preferably 50°C or higher, still more preferably 60°C or higher, and even more preferably 70°C or higher. The aging temperature may be constant during aging, or may be changed stepwise or continuously. The aging time is not particularly limited, but its lower limit value is preferably 2 hours or longer, preferably 3 hours or longer, more preferably 5 hours or longer, still more preferably 8 hours or longer, even more preferably 12 hours or longer, still more preferably 18 hours or longer, and its upper limit value is preferably 30 days or shorter, more preferably 10 days or shorter, still more preferably 4 days or shorter, still more preferably 2 days or shorter, and even more preferably 36 hours or shorter.

[0155] 2-2-3. Hydrothermal Synthesis In hydrothermal synthesis, the raw materials prepared as described above are placed in a pressure-resistant container (e.g., an autoclave container, etc.) after aging, and under self-generated pressure (autogenous pressure) or gas pressurization to an extent that does not inhibit crystallization, with stirring, or while rotating or rocking the container, or in a static state, it is preferably carried out by maintaining a predetermined temperature. Note that aging may also be carried out using a pressure-resistant container in the same manner.

[0156] The reaction temperature during hydrothermal synthesis is not particularly limited, but its lower limit is preferably 80 °C or higher, more preferably 85 °C or higher, still more preferably 90 °C or higher, even more preferably 95 °C or higher, even more preferably 100 °C or higher or 130 °C or higher, and its upper limit is preferably 200 °C or lower, more preferably 190 °C or lower, still more preferably 180 °C or lower.

[0157] The hydrothermal synthesis time is not particularly limited, but its lower limit is preferably 10 hours or longer, more preferably 15 hours or longer, still more preferably 20 hours or longer, and its upper limit is preferably 30 days or shorter, more preferably 10 days or shorter, still more preferably 7 days or shorter, even more preferably 5 days or shorter, even more preferably 4 days or shorter, even more preferably 3 days or shorter, still more preferably 48 hours or shorter, even more preferably 36 hours or shorter, even more preferably 30 hours or shorter. The reaction temperature may be constant during the reaction or may be changed stepwise or continuously.

[0158] For example, in the case of hydrothermal synthesis of MFI type or mordenite (MOR), as the reaction temperature, its lower limit is preferably 110 °C or higher, preferably 120 °C or higher, more preferably 130 °C or higher, more preferably 140 °C or higher, still more preferably 150 °C or higher, even more preferably 160 °C or higher, and its upper limit is preferably 200 °C or lower, more preferably 190 °C or lower, more preferably 180 °C or lower. For example, in the case of hydrothermal synthesis of the LTA type, as the reaction temperature, the lower limit value is preferably 80 °C or higher, more preferably 85 °C or higher, still more preferably 90 °C or higher, even more preferably 95 °C or higher, preferably 100 °C or higher, and as the upper limit value, it is preferably 200 °C or lower, more preferably 190 °C or lower, more preferably 180 °C or lower, still more preferably 160 °C or lower, even more preferably 140 °C or lower, more preferably 130 °C or lower, more preferably 120 °C or lower, more preferably 110 °C or lower, more preferably 100 °C or lower, and the suitable numerical range is 80 to 110 °C. The suitable hydrothermal synthesis time at this time is preferably 15 to 48 hours, more preferably 20 to 36 hours. Note that the conditions for hydrothermal synthesis of the LTA type can be applied as the conditions for hydrothermal synthesis of FAU.

[0159] For example, in the case of CHA type water synthesis, as the reaction temperature, the lower limit value is preferably 100 °C or higher, more preferably 130 °C or higher, still more preferably 140 °C or higher, and as the upper limit value, it is preferably 200 °C or lower, more preferably 190 °C or lower, still more preferably 180 °C or lower. The suitable hydrothermal synthesis time at this time is preferably 20 hours or longer, more preferably 48 hours or longer, still more preferably 60 hours or longer, even more preferably 66 hours or longer, and as the upper limit value, it is more preferably 96 hours or shorter, more preferably 84 hours or shorter, still more preferably 78 hours or shorter.

[0160] By reacting under the above conditions, it becomes possible to obtain an inorganic porous material (preferably zeolite) with a high yield. According to the production method of the present technology, a plant-derived silica waste liquid can be converted into a functional material. Moreover, since the present technology can reduce the disposal cost, the cost of the main product can also be reduced. Moreover, with the present technology, new value can be created from recovered materials and by-products that were conventionally discarded. In addition, since conventional inorganic porous materials used those produced by subjecting ore silica or silica sand to high-temperature treatment at 1200°C together with sodium carbonate to produce sodium silicate, the manufacturing energy was extremely high. On the other hand, this technology has the advantage of low manufacturing energy because it can utilize the waste liquid generated when the main product is alkali-treated at about 100°C.

[0161] 2-2-4. Recovery of Inorganic Porous Material (Preferably Zeolite) After the above hydrothermal synthesis, it is preferable to separate the inorganic porous material (preferably zeolite), which is the product, from the hydrothermal synthesis reaction solution. The obtained inorganic porous material (preferably zeolite) may usually contain both or either an organic structure-directing agent and an alkali metal in the pores. The method for separating the inorganic porous material (preferably zeolite) from the hydrothermal synthesis reaction solution is not particularly limited, but usually includes methods such as filtration, decantation, or direct drying.

[0162] The inorganic porous material (preferably zeolite) separated and recovered from the hydrothermal synthesis reaction solution is washed with water and dried as necessary, and then calcined to obtain zeolite that does not contain an organic structure-directing agent or the like in order to remove the organic structure-directing agent used during production. Also, the organic structure-directing agent can be removed by the treatment method described below.

[0163] For the removal treatment of both or either the organic structure-directing agent and the alkali metal, liquid-phase treatment using an acidic solution or a chemical solution containing an organic structure-directing agent decomposition component, ion-exchange treatment using a resin, or thermal decomposition treatment can be employed, and these treatments may be used in combination. Preferably, it is calcined at a temperature of 300°C to 1000°C in air or an oxygen-containing inert gas, or in an inert gas atmosphere, or under oxygen-free conditions such as in a vacuum, or in an environment where the entry and exit of air to the outside are blocked, or extracted with an organic solvent such as an ethanol aqueous solution, etc., to remove the contained organic structure-directing agent or the like. Preferably, from the perspective of productivity, removal of the organic structure-directing agent or the like by calcination is preferred.

[0164] Regarding the firing temperature in this case, preferably, the lower limit value is preferably 300 °C or higher, more preferably 400 °C or higher, still more preferably 450 °C or higher, and even more preferably 500 °C or higher. Also, preferably, the upper limit value is preferably 900 °C or lower, more preferably 850 °C or lower, and still more preferably 800 °C or lower. As the inert gas, nitrogen or the like can be used. Also, an oxygen-free state such as a vacuum may be used, or an environmental state in which the entry and exit of air to and from the outside are blocked may be used. Also, the firing time is not particularly limited, but preferably, the lower limit value is preferably 1 hour or longer, more preferably 5 hours or longer. Also, preferably, the upper limit value is preferably 20 hours or shorter, more preferably 15 hours or shorter. As the preferred numerical range, it is preferably 1 to 20 hours, more preferably 5 to 15 hours.

[0165] 2-2-5. Production Example of Inorganic Porous Material (Preferably Zeolite)

[0166] In this technology, by using a first Si source composition, which is a plant-derived Si source, as a raw material, various inorganic porous materials (preferably zeolite) can be appropriately produced and provided. Among the first Si source compositions, by using the recovered product obtained by alkali extraction from the carbonized product as the first Si source composition, it is possible to efficiently produce high-quality LTA-type zeolite, CHA-type zeolite, and FAU-type zeolite, respectively, and other zeolites can also be produced well. The plant-derived material used for the carbonized product is preferably a gramineous plant, more preferably rice husk and / or wheat husk. The recovered product obtained by alkali extraction is preferably a recovered product obtained by alkali extraction so as to have a specific NaOH / Si molar ratio. The temperature of alkali extraction is preferably 50 to 120 °C, and the alkali extraction time is preferably 12 to 36 hours. Note that, for the production methods of inorganic porous materials (preferably zeolites) such as LTA-type zeolite, CHA-type zeolite, and FAU-type zeolite according to the present technology, the explanations of each component such as plant-derived materials, carbonization treatment, Si source removal treatment (Si source recovery treatment), alkali treatment, Al source, alkali metal source, and the amount of water, which overlap with the configurations such as the above "2-1." to "2-2-4.", will be omitted as appropriate. However, the explanations such as the above "2-1." to "2-2-4." are also applicable to the present embodiment, and the explanations can be adopted as appropriate.

[0167] 2-2-5-1) Method for producing LTA-type zeolite The present technology can provide a method for producing LTA-type zeolite, which includes using, as at least raw materials, a first Si source composition containing a Si source recovered by alkali extraction after carbonizing a plant-derived raw material (preferably rice husk), and an Al source. It is preferable to use the recovered material containing the Si source obtained by this alkali extraction for producing LTA-type zeolite. Specifically, the alkali extract prepared to have a molar ratio of NaOH / Si of 2.5 to 3.5 is more preferable. By using this alkali extract as the first Si source composition, LTA-type zeolite can be easily produced without using a second Si source composition, and moreover, a single-phase LTA-type zeolite can be produced without an OSDA.

[0168] In addition, when adjusting the gel composition of the LTA-type raw material, one or more selected from an Al source, an alkali metal source, and water may be appropriately blended. At this time, it is preferable to adjust the molar ratio of Si / Al in the raw material to 0.1 to 1.0. For example, it may be adjusted by adding an Al source to the alkali extract. In the method for producing LTA-type zeolite, it is preferable to mix the raw materials adjusted to a specific gel composition before hydrothermal synthesis, and the mixing temperature at this time may be about room temperature of about 10 to 30°C. After mixing the raw materials, it is preferable to perform hydrothermal synthesis, and at this time, it is more preferable to perform hydrothermal synthesis in a static state, and it is not necessary to perform aging before hydrothermal synthesis. The temperature of hydrothermal synthesis is preferably 70 to 110°C, more preferably 80 to 100°C, and the time of hydrothermal synthesis is preferably 12 to 48 hours, more preferably 18 to 30 hours. Furthermore, hydrothermal synthesis may be carried out with stirring or in a static state, but it is preferably carried out in a static state. After hydrothermal synthesis, filtration, washing, and then drying are performed to obtain high-quality LTA-type zeolite. By using an alkali extract with a specific NaOH / Si molar ratio (theoretical ratio), high-quality LTA-type zeolite can be obtained without further calcination after drying. The specific gel composition (molar ratio) which is the raw material for LTA type is more preferably Si 1:Al 0.5 to 3:Na 1 to 8:H20 50 to 200, and even more preferably Si 1:Al 0.5 to 2:Na 1.5 to 8:H20 50 to 70.

[0169] 2-2-5-2) Method for producing CHA-type zeolite This technology can provide a method for producing CHA-type zeolite, which includes performing a treatment of recovering a Si source by alkali extraction after carbonizing a plant-derived raw material (preferably rice husk), and using at least the first Si source composition containing the Si source recovered at this time and an Al source as raw materials. The recovered product containing the Si source obtained by this alkali extraction is preferably used for producing LTA-type zeolite. Specifically, the alkali extract is more preferably prepared so that the molar ratio of NaOH / Si is 0.3 to 0.8. By using this alkali extract as the first Si source composition, CHA-type zeolite can be easily produced without using a second Si source composition, and moreover, a single-phase CHA-type zeolite can be produced without OSDA. In addition, when adjusting the gel composition of the CHA-type raw material, one or more selected from an Al source, an alkali metal source, and water may be appropriately mixed.

[0170] In the method for producing CHA-type zeolite, it is preferable to mix the raw material adjusted to a specific gel composition before hydrothermal synthesis. At this time, the mixing temperature may be about room temperature of about 10 to 30°C. Further, it is more preferable to blend and mix 10 to 30 parts by mass of seed crystals with respect to 100 parts by mass of the raw material. After mixing the raw materials, it is preferable to perform hydrothermal synthesis. At this time, it is more preferable to perform hydrothermal synthesis in a static state, and it is not necessary to perform aging before hydrothermal synthesis. The temperature of hydrothermal synthesis is preferably 70 to 110°C, more preferably 80 to 100°C, and the time of hydrothermal synthesis is preferably 12 to 48 hours, more preferably 18 to 30 hours. Further, hydrothermal synthesis may be performed with stirring or in a static state, but it is preferably performed in a static state. After hydrothermal synthesis, filtration, washing, and then drying are performed to obtain high-quality LTA-type zeolite. By using an alkali extract having a specific NaOH / Si molar ratio (theoretical ratio), high-quality LTA-type zeolite can be obtained even without further calcination after drying.

[0171] In a specific gel composition (molar ratio) of the raw material for CHA type, Si:Al:Na:K:H2O is preferably Si 1:Al 0.1 to 1:Na 0.6 to 2:K 0.01 to 0.5:H2O 10 to 200, preferably Si 1:Al 0.2 to 0.5:Na 0.8 to 1:K 0.05 to 0.15:H2O 50 to 150.

[0172] 2-2-5-3) Method for Producing FAU-Type Zeolite The present technology can provide a method for producing FAU-type zeolite, which includes performing a treatment of recovering a Si source by alkali extraction after carbonizing a plant-derived raw material (preferably rice husk), and using at least as raw materials a first Si source composition containing the Si source recovered at this time and an Al source. The recovered material containing the Si source obtained by this alkali extraction is preferably used for manufacturing FAU-type zeolite. Specifically, the alkali extract prepared with a molar ratio of NaOH / Si of 2.5 to 3.5 is more preferable. By using this alkali extract as the first Si source composition, FAU-type zeolite can be easily manufactured without using the second Si source composition, and moreover, single-phase FAU-type zeolite can be manufactured without OSDA.

[0173] Also, when adjusting the gel composition of the FAU-type raw material, one or more selected from an Al source, an alkali metal source, and water may be appropriately blended. At this time, it is preferable to adjust the molar ratio of Si / Al in the raw material to 1.0 to 2.0. For example, it may be adjusted by adding an alkali extract to an aqueous solution containing an Al source and an alkali metal source. In the method for manufacturing FAU-type zeolite, it is preferable to mix the raw material adjusted to a specific gel composition before hydrothermal synthesis. The mixing temperature at this time may be about room temperature of about 10 to 30°C. After mixing the raw materials, it is preferable to perform hydrothermal synthesis. At this time, it is more preferable to perform hydrothermal synthesis in a static state, and it is not necessary to perform aging before hydrothermal synthesis. The temperature of hydrothermal synthesis is preferably 70 to 110°C, more preferably 80 to 100°C, and the time of hydrothermal synthesis is preferably 12 to 48 hours, more preferably 18 to 30 hours. Furthermore, hydrothermal synthesis may be performed with stirring or in a static state, but it is preferably performed in a static state. After hydrothermal synthesis, filtration, washing, and then drying can obtain high-quality FAU-type zeolite. By using an alkali extract with a specific NaOH / Si molar ratio (theoretical ratio), high-quality LTA-type zeolite can be obtained without further calcination after drying. The specific gel composition (molar ratio) of the raw material for FAU-type is more preferably Si 1:Al 0.5 to 3:Na 1 to 8:H20 50 to 200, and even more preferably Si 1:Al 0.5 to 2:Na 1.5 to 8:H20 50 to 70.

[0174] <3. Porous Material of the Present Technology> The porous material (preferably zeolite) of the present technology can be obtained by the above <2. Method for producing the porous material of the present technology>. Generally, zeolites are known to exhibit various physicochemical effects such as molecular sieving action, cation exchangeability, reversible water adsorption / desorption action, catalytic action, gas adsorption action, etc. The porous material of the present technology can also have such physicochemical effects. Due to such physicochemical effects, the porous material of the present technology can be used in a wide variety of fields such as the petrochemical industry, wastewater treatment, detergent builders, radioactive waste treatment, livestock industry, fisheries industry, agriculture, separation of oxygen and nitrogen in the air, small heat pump systems, etc.

[0175] By using the first Si source composition of the present technology, LTA-type zeolite, CHA-type zeolite, zeolite X (FAU-type), mordenite (MOR), ZSM-5 (MFI), FAU-type zeolite, sodalite (SOD-type zeolite), GIS-type zeolite, zeolite Y (FAU-type) can be obtained, and one or more kinds can be produced from the group consisting of these. Furthermore, in the present technology, by using the recovered product containing the Si source obtained by alkali extraction as the first Si source composition, it is also possible to efficiently produce high-quality LTA-type zeolite and CHA-type zeolite respectively. LTA-type zeolite and CHA-type zeolite can be used in the production of biofuels (for example, bioethanol) (for example, for water removal, etc.).

[0176] Also, in the production method of the present technology using a raw material containing a plant-derived Si source as described above, a porous material can be obtained by increasing the molar ratio of Al in the gel composition of the raw material. By increasing Al, it is possible to make it easier to adsorb heavy metal M (for example, radioactive substances such as Cs, Sr, etc.). For example, by mixing the object to be treated containing heavy metal M with an aqueous solution containing the porous material, the heavy metal M can be adsorbed.

[0177] The Si / Al composition ratio (mass / mass) in the porous material (more preferably zeolite) in the present technology is not particularly limited. However, as a preferable lower limit value, it is preferably 0.05 or more, more preferably 0.1 or more, still more preferably 0.5 or more, and even more preferably 1 or more. As a preferable upper limit value, it is preferably 200 or less, more preferably 100 or less, still more preferably 50 or less. The preferable numerical range of the Si / Al composition ratio (mass ratio) in the raw material is more preferably 1 to 120, and more preferably 1.0 to 50. The molar ratio in the porous material can be converted from this Si / Al composition ratio (mass / mass) by Si(28.1) / Al(26.98).

[0178] For example, in the case of the MFI type, the Si / Al composition ratio (mass / mass) in the zeolite is not particularly limited. However, as a preferable lower limit value, it is preferably 1 or more, more preferably 5 or more, still more preferably 10 or more. As a preferable upper limit value, it is preferably 100 or less, more preferably 50 or less, still more preferably 20 or less. For example, in the case of mordenite, the Si / Al composition ratio (mass / mass) in the zeolite is not particularly limited. However, as a preferable lower limit value, it is preferably 2 or more, more preferably 5 or more, still more preferably 10 or more. As a preferable upper limit value, it is preferably 100 or less, more preferably 50 or less, still more preferably 30 or less, and even more preferably 20 or less.

[0179] For example, in the case of the LTA type, the Si / Al composition ratio (mass / mass) in the zeolite is not particularly limited. However, as a preferable lower limit value, it is preferably 0.1 or more, preferably 0.2 or more, still more preferably 0.5 or more. As a preferable upper limit value, it is preferably 5 or less, more preferably 3 or less, still more preferably 2 or less.

[0180] For example, in the case of the CHA type, the Si / Al composition ratio (mass / mass) in the zeolite is not particularly limited, but as its preferable lower limit, it is preferably 1 or more, preferably 5 or more, more preferably 10 or more. Also, as its preferable upper limit, it is preferably 300 or less, more preferably 200 or less, and even more preferably 150 or less.

[0181] For example, in the case of the FAU type, the Si / Al composition ratio (mass / mass) in the zeolite is not particularly limited, but as its preferable lower limit, it is preferably 0.01 or more, preferably 0.05 or more, more preferably 0.1 or more. Also, as its preferable upper limit, it is preferably 100 or less, more preferably 20 or less, and even more preferably 10 or less.

[0182] The average particle diameter of the porous material (more preferably zeolite) in the present technology is not particularly limited, but its preferable lower limit is preferably 10 nm or more, more preferably 25 nm or more. Furthermore, in the case of the MFI type, the average particle diameter is not particularly limited, but its preferable lower limit is preferably 10 nm or more, more preferably 25 nm or more, and its preferable upper limit is preferably 800 nm or less, more preferably 500 nm or less. The preferable numerical range is preferably 25 to 800 nm, more preferably 50 to 500 nm. Furthermore, in the case of the LTA type, the average particle diameter is not particularly limited, but its preferable lower limit is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. Also, as its preferable upper limit, it is preferably 100 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. The preferable numerical range is preferably 1 to 10 μm. The LTA type with such an average particle diameter can be obtained by using the alkali extract of the present technology. Furthermore, in the case of the CHA type, dish-shaped secondary particles composed of nanoparticles are observed. The size of the dish-shaped secondary particles is not particularly limited, but the preferred lower limit is preferably 1 μm or more, more preferably 2 μm or more. The preferred upper limit is preferably 5 μm or less, more preferably 4 μm or less. The preferred numerical range is preferably 2 to 4 μm. Note that the secondary particle diameter is the size of the aggregated particles, and the size of the dish-shaped secondary particles is measured by measuring the size of the aggregated particles and can be measured by the same measurement method as the average particle diameter.

[0183] The value (S BET ) of the specific surface area of the porous material (more preferably zeolite) in the present technology by the nitrogen BET method is not particularly limited, but the preferred lower limit is preferably 25 m 2 / g or more, more preferably 50 m 2 / g or more, even more preferably 100 m 2 / g or more. The preferred upper limit is preferably 800 m 2 / g or less, more preferably 500 m 2 / g or less. The preferred numerical range is preferably 100 to 450 m 2 / g. The value (S BET ) of the specific surface area by the nitrogen BET method is preferably 200 to 700 m 2 / g, more preferably 300 to 600 m 2 / g in the case of the MFI type, and preferably 50 to 500 m 2 / g, more preferably 100 to 400 m 2 / g in the case of mordenite, but is not limited thereto.

[0184] The value (S EXT ) of the external surface area obtained by analyzing the nitrogen adsorption evaluation data of the porous material (more preferably zeolite) in the present technology by the t-plot method is not particularly limited, but the preferred lower limit is preferably 5 m 2 / g or more, more preferably 10 m 2 / g or more, even more preferably 20 m 2above / g, and its preferable upper limit value is preferably 500 m 2 / g or less, more preferably 400 m 2 / g or less, and the preferable numerical range is preferably 20 - 400 m 2 / g. The external surface area (S EXT ) value obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method is preferably 10 - 500 m 2 / g for the MFI type, more preferably 20 - 400 m 2 / g, and for mordenite, it is preferably 0.5 - 200 m 2 / g, more preferably 1 - 100 m 2 / g, but not limited thereto.

[0185] The total pore volume (V total ) value determined by the BET method in the porous material (more preferably zeolite) in the present technology is not particularly limited, but its preferable lower limit value is preferably 0.01 cm 3 / g or more, more preferably 0.05 cm 3 / g or more, still more preferably 0.1 cm 3 / g or more, and its preferable upper limit value is preferably 2.0 cm 3 / g or less, more preferably 1.0 cm 3 / g or less, and the preferable numerical range is preferably 0.1 - 1.0 cm 3 / g. The total pore volume (V total ) value determined by the BET method is preferably 0.05 - 1.0 cm 3 / g for the MFI type, more preferably 0.1 - 1.0 cm 3 / g, and for mordenite, it is preferably 0.05 - 1.0 cm 3 / g, more preferably 0.1 - 0.5 cm 3 / g, but not particularly limited thereto.

[0186] The micropore volume (V micro) The value is not particularly limited, but its preferable lower limit is preferably 0.005 cm 3 / g or more, more preferably 0.01 cm 3 / g or more, and its preferable upper limit is preferably 0.5 cm 3 / g or less, more preferably 0.2 cm 3 / g or less, and the preferable numerical range is preferably 0.01 - 0.2 cm 3 / g. The micropore volume (V micro ) value analyzed by the t-plot method for nitrogen adsorption evaluation data is preferably 0.01 - 0.1 cm 3 / g, more preferably 0.05 - 0.2 cm 3 / g in the case of MFI type, and preferably 0.01 - 0.2 cm 3 / g, more preferably 0.05 - 0.2 cm 3 / g in the case of mordenite, and is not particularly limited to these.

[0187] 4. Si source composition for producing porous material This technology can provide a Si source composition for producing a porous material, which contains a recovered product containing a Si source recovered when a treatment for removing the Si source (a treatment for recovering the Si source) is performed after carbonizing a plant-derived raw material. The composition is suitable for mordenite (MOR type zeolite), MFI type zeolite, LTA type zeolite (zeolite A), CHA type zeolite, FAU type zeolite (zeolite X), and SOD type zeolite. Among these, since a pure-phase LTA type zeolite and a single-phase CHA type zeolite can be obtained, it is more suitable for LTA type zeolite (zeolite A) and CHA type zeolite.

[0188] After carbonizing the plant-derived raw material, a treatment for removing the Si source is performed, and the "recovered product containing a Si source" recovered at this time is hereinafter also referred to as "plant-derived first Si source recovered product". For the parts of the plant-derived first Si source recovery product in the present technology that are the same as the composition and manufacturing method of the "first Si source composition" described in "2-1-1. First Si source composition" and "2-1-1-2. Si source derived from plants and its manufacturing method" of "<2. Manufacturing method of the porous material of the present technology>", they will be omitted as appropriate.

[0189] Therefore, the Si source composition for manufacturing the porous material (preferably zeolite) of the present technology contains at least a plant-derived first Si source recovery product as an active ingredient. That is, the plant-derived first Si source recovery product in the present technology can be contained in the Si source composition for manufacturing the porous material as an active ingredient and used.

[0190] In addition, the Si source composition for manufacturing the porous material in the present technology can be contained in compositions expecting various effects as an active ingredient, and these various compositions can also be used as agents. The Si source composition for manufacturing the porous material in the present technology can be used as the components themselves alone as they are, or can also be used after being mixed with acceptable ordinary monomers or diluents, etc. In addition, the Si source composition for manufacturing the porous material in the present technology can be used in various fields such as medicine, agriculture, and food.

[0191] In addition, the present technology can provide a plant-derived first Si source or its use for purposes such as manufacturing the above-mentioned porous material (preferably zeolite). In addition, the plant-derived first Si source recovery product in the present technology can be used as an active ingredient of the composition used in the above-mentioned manufacturing method, use, usage method, etc. In addition, the plant-derived first Si source recovery product in the present technology can be used for manufacturing various preparations or various compositions, etc. for having the above-mentioned effects or for the above-mentioned use purposes. The present technology can also provide a Si source composition for manufacturing a porous material, which has a plant-derived first Si source recovery product as an active ingredient. The present technology can also provide a method for manufacturing a porous material using a plant-derived first Si source recovery product. The present technology can also provide a plant-derived first Si source recovery product or its use for manufacturing a porous material.

[0192] 5. Each measurement method of the present technology <ICP analysis> The analysis of various elements in the present technology can be measured with an ICP emission spectrometer (ICPE-9000 manufactured by Shimadzu Corporation).

[0193] <Atomic absorption spectrometry> The various elements measured by atomic absorption spectrometry (AAs) can be measured with an AA-6200 spectrometer device manufactured by Shimadzu Corporation.

[0194] <X-ray diffraction method> XRD: Evaluated by the X-ray diffraction method (RINT-UltimaIII-TK (manufactured by Rigaku)). The nitrogen adsorption measurement can be evaluated with BELSORP-MAX (manufactured by Nippon Bell).

[0195] <Average particle size> The average particle size in the present technology was determined based on JIS Z 8827-1 Part 1: Static image analysis method, and the calculation of the average particle size at this time was performed according to JIS Z 8819-2.

[0196] <Nitrogen BET method> The nitrogen BET method in the present technology is a method of measuring an adsorption isotherm by adsorbing and desorbing nitrogen as an adsorbing molecule to an adsorbent (here, a porous carbon material), and analyzing the measured data based on the BET equation represented by Equation (1). Based on this method, the specific surface area, pore volume, etc. can be calculated.

[0197] Specifically, when calculating the specific surface area value by the nitrogen BET method, first, nitrogen is adsorbed and desorbed as an adsorbing molecule on the "sample" to obtain an adsorption isotherm. Then, from the obtained adsorption isotherm, [p / {Va(p0 - p)}] is calculated based on Equation (1) or Equation (1') obtained by transforming Equation (1), and plotted against the equilibrium relative pressure (p / p0). Then, regarding this plot as a straight line, based on the least squares method, the slope s (=[(C - 1) / (C·Vm)]) and the intercept i (=[1 / (C·Vm)]) are calculated.

[0198] Then, based on Equation (2-1) and Equation (2-2), Vm and C are calculated from the obtained slope s and intercept i. Further, from Vm, the specific surface area asBET is calculated based on Equation (3) (see pages 62 to 66 of the manual of BELSORP-mini manufactured by Nippon Bell Co., Ltd. and BELSORP analysis software). Note that this nitrogen BET method is a measurement method in accordance with JIS R 1626-1996 "Method for Measuring Specific Surface Area of Fine Ceramics Powder by Gas Adsorption BET Method".

[0199] Va=(Vm·C·p) / [(p0 - p){1+(C - 1)(p / p0)}] (1) [p / {Va(p0 - p)}] =[(C - 1) / (C·Vm)](p / p0)+[1 / (C·Vm)] (1’) Vm = 1 / (s + i) (2-1) C =(s / i)+1 (2-2) asBET=(Vm·L·σ) / 22414 (3)

[0200] However, Va: Adsorption amount Vm: Adsorption amount of monolayer p: Pressure at equilibrium of nitrogen p0: Saturated vapor pressure of nitrogen L: Avogadro's number σ: Adsorption cross-sectional area of nitrogen is as follows.

[0201] <Nitrogen BET method - Pore volume> When calculating the pore volume Vp by the nitrogen BET method in the present technology, for example, the adsorption data of the obtained adsorption isotherm is linearly interpolated to obtain the adsorption amount V at the relative pressure set at the relative pressure for pore volume calculation. The pore volume Vp can be calculated from this adsorption amount V based on Equation (4) (refer to the manuals of BELSORP-mini and BELSORP analysis software manufactured by Nippon Bell Co., Ltd., pages 62 to 65). Incidentally, the pore volume based on the nitrogen BET method may be simply referred to as the "pore volume" hereinafter.

[0202] Vp = (V / 22414) × (Mg / ρg) (4)

[0203] However,[[]] V: Adsorption amount at relative pressure Mg: Molecular weight of nitrogen ρg: Density of nitrogen is.

[0204] <Pore diameter of mesopores>[[]] In the present technology, the pore diameter of mesopores can be calculated as a pore distribution from the change rate of pore volume with respect to the pore diameter, for example, based on the BJH method. The BJH method is a method widely used as a pore distribution analysis method. When performing pore distribution analysis based on the BJH method, first, nitrogen is adsorbed and desorbed as an adsorbing molecule to the "sample" to obtain a desorption isotherm. Then, based on the obtained desorption isotherm, the thickness of the adsorption layer when the adsorbing molecules are desorbed step by step from the state where the pores are filled with the adsorbing molecules (for example, nitrogen), and the inner diameter of the pores (twice the core radius) generated at that time are obtained, the pore radius rp is calculated based on Equation (5), and the pore volume is calculated based on Equation (6). Then, a pore distribution curve is obtained by plotting the change rate of pore volume (dVp / drp) with respect to the pore diameter (2rp) from the pore radius and the pore volume (refer to the manuals of BELSORP-mini and BELSORP analysis software manufactured by Nippon Bell Co., Ltd., pages 85 to 88).

[0205] rp = t + rk (5) Vpn = Rn·dVn - Rn·dtn·c·ΣApj (6) However, Rn = rpn2 / (rkn - 1 + dtn)2 (7)

[0206] Here, rp: Pore radius rk: Core radius (inner diameter / 2) when an adsorption layer with thickness t is adsorbed on the inner wall of the pore with pore radius rp at that pressure Vpn: Pore volume when the nth adsorption and desorption of nitrogen occur dVn: Change amount at that time dtn: Change amount of the thickness tn of the adsorption layer when the nth adsorption and desorption of nitrogen occur rkn: Core radius at that time c: Fixed value rpn: Pore radius when the nth adsorption and desorption of nitrogen occur. Also, ΣApj represents the integrated value of the areas of the pore walls from j = 1 to j = n - 1.

[0207] <Pore diameter of micropores> In the present technology, the pore diameter of micropores can be calculated as the pore distribution from the pore volume change rate with respect to the pore diameter, for example, based on the MP method. When performing pore distribution analysis by the MP method, first, nitrogen is adsorbed on the "sample" to obtain the adsorption isotherm. Then, this adsorption isotherm is converted to the pore volume with respect to the thickness t of the adsorption layer (t-plot). And a pore distribution curve can be obtained based on the curvature of this plot (the change amount of the pore volume with respect to the change amount of the thickness t of the adsorption layer) (see pages 72 - 73 and page 82 of the manual of BELSORP-mini and BELSORP analysis software manufactured by Nippon Bell Co., Ltd.).

[0208] In the non-local density functional theory (NLDFT method) defined in JIS Z8831-2:2010 "Pore Size Distribution and Pore Characteristics of Powders (Solids) - Part 2: Measurement Method for Mesopores and Macropores by Gas Adsorption" and JIS Z8831-3:2010 "Pore Size Distribution and Pore Characteristics of Powders (Solids) - Part 3: Measurement Method for Micropores by Gas Adsorption", the software attached to the automatic specific surface area / pore distribution measuring device "BELSORP-MAX" manufactured by Nippon Bell Co., Ltd. is used as the analysis software. As a prerequisite, the model is assumed to be a cylinder shape and carbon black (CB) is assumed, the distribution function of the pore distribution parameters is set to "no-assumption", and the obtained distribution data is smoothed 10 times.

[0209] Note that the external surface area (S EXT ) value, the total pore volume (V total ) value, the micropore volume (V micro)For each measurement method of values, reference can be made to (1) "Characterization of Porous Solids and Powders: Surface Area, Pore Size and Density", Seymour Lowell, Joan E. Shields, Martin A. Thomas, Matthias Thommes, Springer Science & Business Media, 2006.; (2) "Introduction to Zeolite Science and Practice", P.A. Jacobs, E.M. Flanigen, J.C. Jansen, Herman van Bekkum, Elsevier, 2001.; (3) "Characterization of Micro / Mesoporous Materials by Physisorption: Concepts and Case Studies", Francisco J. Sotomayor, Katie A. Cychosz, Matthias Thommes, Acc. Mater. Surf. Res. 2018, Vol.3 (No.2), 34-50,; (4) "Science of Adsorption", Seiichi Kondo, Tatsuo Ishikawa, Ikuo Abe, Maruzen Publishing Co., Ltd., 2001.

[0210] In this technology, the following configurations can also be adopted. [1] A method for producing a porous material containing Si and Al, which uses at least a first Si source composition derived from a plant and an Al source as raw materials. Preferably, the raw materials further include a second Si source composition. Also preferably, the first Si source composition is a recovered product containing a Si source obtained by an alkali treatment, more preferably a recovered product containing a Si source obtained by an alkali extraction, and it is even more preferable that the recovered product of the alkali extraction is a recovered product obtained by an alkali extraction adjusted to a specific NaOH / Si molar ratio. [2] The first Si source composition is After carbonizing the plant-derived raw material, a process of recovering the Si source is performed, and the manufacturing method of the porous material described in [1], which is the Si source recovered at this time. [3] The manufacturing method of the porous material according to [1] or [2], wherein the first Si source composition has a silicon content of 100 g / L or more. [4] The manufacturing method of the porous material according to any one of [1] to [3], wherein the Si / Al composition ratio of the first Si source composition is 50 to 100, and / or the Si / Al composition ratio of the porous material is 1 to 120. [5] The manufacturing method of the porous material according to any one of [1] to [4], wherein the second Si source is a Si source derived from minerals and / or a Si source derived from plants. [6] The manufacturing method of the porous material according to any one of [1] to [5], wherein the second Si source composition is a processed product obtained by decarbonizing a plant-derived raw material. [7] The manufacturing method of the porous material according to any one of [1] to [6], wherein the second Si source composition is plant-derived ash. [8] The first Si source composition is a Si source recovered by performing a process of recovering the Si source after carbonizing a plant-derived raw material, and The manufacturing method of the porous material according to any one of [1] to [7], wherein the second Si source composition is plant-derived ash. [9] The manufacturing method of the porous material according to any one of [1] to [8], further using an organic structure-directing agent as a raw material.

[10] The manufacturing method of the porous material according to any one of [1] to [9], wherein a heat treatment is performed on a mixture of a first Si source composition that is a plant-derived Si source and the Al source. Preferably, the mixture further contains a second Si source composition.

[11] The manufacturing method of the porous material according to

[10] , wherein the heat treatment is hydrothermal synthesis.

[12] The manufacturing method of the porous material according to any one of

[10] or

[11] , wherein the heat treatment is carried out in the order of stirring and aging, and then hydrothermal synthesis. 〔13〕 The manufacturing method of the porous material according to any one of [1] to

[12] , wherein the first Si source composition is an aqueous solution recovered by removing silica from a plant-derived raw material containing silica. 〔14〕 The manufacturing method of the porous material according to any one of [1] to

[13] , wherein the porous material is zeolite. 〔15〕 The manufacturing method of the porous material according to any one of [1] to

[14] , wherein the plant is a gramineous plant. 〔16〕 A porous material obtained by the manufacturing method of the porous material according to any one of [1] to

[15] . The porous material is preferably one or more selected from the group consisting of A-type (LTA), CHA-type, zeolite X (FAU-type), mordenite (MOR), beta-type (BEA), ZSM-5 (MFI), and zeolite Y (FAU-type). 〔17〕 A Si source composition for producing a porous material, which is obtained by carbonizing a plant-derived raw material and then recovering a Si source, and contains the Si source recovered at this time.

Examples

[0211] Hereinafter, the present technology will be described in more detail based on test examples, examples, etc. The test examples, examples, etc. described below show an example of typical test examples, examples, etc. of the present technology, and the scope of the present technology is not construed narrowly thereby. In addition, each measured value in the [Examples] of the present technology below can be obtained by the "5. Each measurement method of the present technology" described above.

[0212] <Production Example A: First Si source composition / Silica waste liquid (alkali treatment) during the production of porous carbon material derived from rice husk> After carbonizing rice husk, a plant-derived material (silicon content: approximately 9% by mass) at 400°C to 1400°C, a porous carbon material was obtained by treating it with an alkali of sodium hydroxide. As a by-product during this alkali treatment, a silica waste liquid was obtained. This silica waste liquid was used as a raw material for manufacturing the porous material of the present technology, and this silica waste liquid was used as a first Si source composition. This will be described in more detail below.

[0213] <Production Example A1> First, heat treatment (pre-carbonization treatment) was performed on the rice husk in an inert gas. Specifically, as the pre-carbonization treatment, the rice husk was carbonized by heating in a nitrogen stream at 500°C for 5 hours to obtain a carbide. By performing such treatment, it is possible to reduce or remove the tar component that would be generated during the subsequent carbonization. After the pretreatment, 10 grams of this carbide was placed in an alumina crucible and heated to 800°C at a heating rate of 5°C / min in a nitrogen stream (10 liters / min). Then, it was carbonized at 800°C for 1 hour to convert it into a carbonaceous substance (precursor of the porous carbon material), and then cooled to room temperature. During carbonization and cooling, nitrogen gas was continuously flowed. Note that if the temperature control of the carbonization treatment is performed, the heating rate does not particularly need to be controlled. Next, this precursor of the porous carbon material was immersed in a 30% by mass aqueous sodium hydroxide solution at a temperature in the range of 80 to 100°C overnight (about 12 hours), and then alkali treatment was performed by heat treatment at 100°C for 1 hour in a pressure-resistant container. After that, it was washed with water until the precursor of the porous carbon material reached pH 7. The alkali treatment waste liquid (pH 13 or higher) generated in this way was collected and stored at room temperature of about 10 to 30°C for about 1 day. This alkali treatment waste liquid was used as the silica waste liquid used in the present technology (silica waste liquid of Production Example A1). Note that the precursor of the porous carbon material can be immersed in a 5% by mass aqueous sodium hydroxide solution at a temperature in the range of 80 to 100°C overnight (about 12 to 14 hours), washed as described above, to obtain an alkali treatment waste liquid, and this can be used as the silica waste liquid. The washed carbonaceous substance (precursor of the porous carbon material) was dried and then subjected to an activation treatment with a steam flow at 90 °C to obtain a porous carbon material.

[0214] The silica waste liquid obtained above was allowed to stand overnight and filtered through a paper filter and a glass filter with a pore size of 0.1 μm or less for solid-liquid separation. The filtered silica waste liquid was used as the first Si source composition of the present technology. The filtered silica waste liquid had a pH of 13.89. By ICP emission analysis (ICP emission analyzer: ICPE-9000 manufactured by Shimadzu Corporation), it was found that Na was 820 g / L, Si was 245.5 g / L, Si / Na = 0.25, and Si / Al = 73.34. Carbon was not detected, and it was considered that the carbon-based material could be removed by filtration.

[0215] <Production Example B: Second Si Source Composition / Silica Ash Derived from Rice Hulls> <Production Example B1> Rice hulls, which are plant-derived materials, were calcined at 500 °C for 10 hours while blowing air at an air flow rate of 200 mL / min to obtain silica ash from the rice hulls. The yield at this time was 19.5% (Production Example B1). The yield (%) was calculated as (ash of rice hulls / rice hulls) × 100. This silica ash from the rice hulls was used as the plant-derived second Si source composition in the present technology. The ash of the rice hulls was analyzed by ICP emission analysis similar to that in Production Example A above. The silica ash of this rice hulls was Si (silicon) - 91.11%, K (potassium) - 5.15%, Ca (calcium) - 1.06%, Fe (iron) - 0.51%, P (phosphorus) - 0.48%, and others - 1.69% (Al was 1.0% or less).

[0216] <Production Example B2-4> In addition, silica ash from the rice hulls was obtained in the same manner except that the temperature and time of the above calcination conditions were changed to "400 °C, 5 hours", and the yield was 20% (Production Example B2). In addition, silica ash from the rice hulls was obtained in the same manner except that the temperature and time of the above calcination conditions were changed to "400 °C, 10 hours", and the yield was 20% (Production Example B3). In addition, in the same manner except that the temperature and time of the firing conditions were changed to "600 °C, 10 hours", rice husk ash was obtained, and the yield was 20% (Production Example B4). Production Example B1 (500 °C, 10 hours) is preferable from the viewpoints of production time and yield.

[0217] <Production Example B5> In the same manner as the method for producing the porous carbon material precursor of Production Example A1, a porous carbon material precursor was obtained and used as rice husk charcoal (RHC). This rice husk charcoal was further fired at 550 °C for 8 hours while blowing air at an air flow rate of 300 mL / min to obtain silica ash of rice husk. Note that the rice husk ash obtained in Production Examples B2-5 can also be used as the first Si source composition. In addition, as the characterization of rice husk ash (RHC), the TG of rice husk ash was measured. As a result, water: temperature 20 to 150 °C, content 32.2%; carbon-based: temperature 150 to 550 °C, content 24.8%; silicon-based: 550 to 1000 °C, content 42.0%.

[0218] <Production Example C: Method for Producing Porous Material> Table 1 shows an overview of the production methods of Examples 1 to 4 and Comparative Example 1.

[0219]

Table 1

[0220] Before preparing the Si source composition, the compositions of H2O, Si, Na, etc. in the silica waste liquid and the composition of Si / Na, etc. in the silica ash were confirmed by ICP analysis respectively. The raw materials of the porous material such as the silica waste liquid and the silica ash were mixed to prepare a gel having the target molar composition. Specifically, the ash of rice husk (Production Example B1) was added to the silica waste liquid (Production Example A1) obtained above to prepare a plant-derived Si source composition. An Al source composition was further added to the raw materials of this Si source composition to obtain the raw materials for the porous material. At this time, since water was contained in the silica waste liquid, the porous material could be produced without particularly adding water. However, water was appropriately added to adjust the molar ratio of each component of the gel composition of the raw materials. Finally, a first Si source composition (first Si source solution), a second Si source composition, and an Al source were prepared so as to obtain a final gel composition (molar ratio), and the raw materials for the porous material were obtained. At this time, an organic structure-directing agent was appropriately used. By using a plant-derived Si source composition, a silica-based porous material could be produced with or without using an organic structure-directing agent (OSDA: Organic Structure -Directing·Agent).

[0221] <Example 1: Synthesis of MFI-type zeolite using a plant-derived Si source composition> As the raw materials of Example 1, the silica waste liquid of Production Example A1, the silica rice husk ash of Production Example B1, an organic structure-directing agent (OSDA: TPAOH), water, and Al(NO3)3·9H2O were used so that the gel composition (molar ratio) in the final raw material composition was Si:TPAOH:Al:Na + :H2O = 1: 0.25: 0.1: 0.1: 10. At this time, Al(NO3)3·9H2O was introduced into the raw material composition after aging and before hydrothermal synthesis.

[0222] The silica waste liquid of the above Production Example A1, the silica rice husk ash of the above Production Example B1, an organic structure directing agent (OSDA: TPAOH), and water were put into an autoclave container (a sealed container with a Teflon (registered trademark) inner side and a SUS cover outside) and mixed to prepare a raw material composition a1. Inside the autoclave container (in a sealed state), the raw material composition a1 was aged at 80 °C for 24 hours while rotating and stirring. Then, Al(NO3)3·9H2O was further introduced into the raw material composition a1 as a raw material a2 to prepare a final raw material composition A. This raw material composition A was hydrothermally synthesized at 170 °C for 24 hours inside the autoclave container (in a sealed state). What was obtained by this reaction was designated as ZSM-5-As made. Thereafter, it was reacted at 550 °C for 10 hours in the atmosphere to evaporate excess water and OSDA, thereby obtaining the Na-ZSM-5 of Example 1. Then, the zeolite of Example 1 was obtained by ion exchange using 2.5 M NH4NO3 (ammonium nitrate). This zeolite was H-ZSM-5 (MFI type) as determined by XRD and the like.

[0223] <Comparative Example 1: Synthesis of Zeolite Using a Mineral-Based Silica Source> As raw materials for Comparative Example 1, the following Si source, Al source, water, and organic structure directing agent were used, and the gel composition (molar ratio) in the final raw material composition was TEOS : TPAOH : Al : Na + : H2O = 1 : 0.25 : 0.04 : 0.1 : 8.3 to 100. Note that as the Si source, a mineral-based silica, tetraethoxysilane (TEOS) available as a commercial product, was used. Tetraethoxysilane (TEOS), an organic structure directing agent (OSDA: TPAOH), and water were put into an autoclave container and mixed to prepare a raw material composition b1. Inside the autoclave container (in a sealed state), the raw material composition b1 was aged at 80 °C for 24 hours while rotating and stirring. Subsequently, Al(NO3)3·9H2O was further introduced into the raw material composition b1 as the raw material b2 to prepare the final raw material composition B. This raw material composition B was hydrothermally synthesized at 170 °C for 24 hours in an autoclave container (sealed state). (The product obtained from this reaction is designated as ZSM-5-As made.) Subsequently, the reaction was carried out at 550 °C for 10 hours in the atmosphere to evaporate excess water and OSDA, thereby obtaining the Na-ZSM-5 of Comparative Example 1. Subsequently, by ion-exchanging with 2.5 M NH4NO3 (ammonium nitrate), the zeolite of Comparative Example 1 was obtained. This zeolite was H-ZSM-5 (MFI type) as determined by XRD and the like.

[0224] <Example 2: Synthesis of Zeolite without OSDA Using a Plant-Derived Si Source Composition> As raw materials for Example 2, the silica waste liquid of Production Example A1 and the silica rice husk ash of Production Example B1 described above, water, and NaAlO2 were used to prepare a gel composition (molar ratio) in the final raw material composition such that Si:Al:Na + :H2O = 1:0.1:0.4:25. Note that in Example 2, an organic structure-directing agent (OSDA: TPAOH) was not used.

[0225] The silica waste liquid of Production Example A1, the silica rice husk ash of Production Example B1, NaAlO2, and water were placed in an autoclave container (with a Teflon (registered trademark) inner side and a SUS cover on the outside) and mixed to prepare the raw material composition C. This raw material composition C was aged at 80 °C for 24 hours with rotation and stirring in an autoclave container (sealed state). Subsequently, this raw material composition C was hydrothermally synthesized at 170 °C for 24 hours in an autoclave container (sealed state), and then ion-exchanged in an aqueous solution of 2.5 M NH4NO3 (ammonium nitrate) to obtain the zeolite of Example 2. This zeolite was mordenite as determined by XRD and the like.

[0226] <Example 3: Synthesis of MFI-Type Zeolite Using a Plant-Derived Si Source Composition> As raw materials for Example 3, the silica waste liquid of Production Example A1 and the silica rice husk ash of Production Example B1, water, and NaAlO2 were used, and the gel composition (molar ratio) in the final raw material composition was Si: Al: Na + : H2O = 1: 0.067: 0.4: 25 was prepared. In Example 3, an organic structure-directing agent (OSDA: TPAOH) was not used.

[0227] The silica waste liquid of Production Example A1, the silica rice husk ash of Production Example B1, NaAlO2, and water were put into an autoclave container and mixed to prepare a raw material composition D. This raw material composition D was aged at 80°C for 24 hours while rotating and stirring in an autoclave container (sealed state). After aging, it was hydrothermally synthesized at 170°C for 24 hours in an autoclave container (sealed state). After hydrothermal synthesis, the zeolite of Example 3 was obtained by ion exchange in a 2.5 M NH4NO3 (ammonium nitrate) aqueous solution. This zeolite was ZSM-5 (MFI type) by XRD and the like.

[0228] <Example 4: Synthesis of LTA-type zeolite using a plant-derived Si source composition> As raw materials for Example 4, the silica waste liquid of Production Example A1 and the silica rice husk ash of Production Example B1, water, and NaAlO2 were used, and the gel composition (molar ratio) in the final raw material composition was Si: Al: Na + : H2O = 1: 1: 6: 150 was prepared. In Example 4, an organic structure-directing agent (OSDA: TPAOH) was not used.

[0229] The silica waste liquid of Production Example A1, the silica rice husk ash of Production Example B1, NaAlO2, and water were put into an autoclave container and mixed to prepare a raw material composition E. This raw material composition E was hydrothermally synthesized at 120°C for 48 hours with rotation and stirring in an autoclave container (in a sealed state). After hydrothermal synthesis, it was further washed and dried, and then calcined at 550°C for 10 hours in the atmosphere to obtain the zeolite of Example 4. This zeolite was zeolite A (LTA type) as determined by XRD and the like. The zeolite of this Example 4 was a cubic-shaped zeolite with a side length of about 3 μm.

[0230] <Examples 1 and Comparative Example 1> The zeolite of Example 1 is characterized in that the zeolite synthesis process is almost the same as that of conventional mineral-derived zeolites, but the origin of the raw materials is very different. The XRD results of the zeolites of Example 1 and Comparative Example 1 are shown in Fig. 1. Since the MFI phase was observed in both, the zeolites of Example 1 and Comparative Example 1 were of the MFI type. This shows that MFI-type zeolites can be synthesized even using plant-derived Si sources (specifically, plant-derived silica waste liquid and plant-derived silica ash). Furthermore, since mineral-based silica such as that in Comparative Example 1 is produced at about 1000°C, the manufacturing energy of mineral-based silica is very high. On the other hand, the plant-derived silica of Example 1 can effectively utilize by-products to be discarded, and since it can be produced in the range of 500°C to 100°C, it can be said that the manufacturing energy is low.

[0231] Furthermore, the adsorption isotherms of the zeolites of Example 1 and Comparative Example 1 are shown in Fig. 2. From Fig. 2, the pores of the zeolite of Example 1 tend to be much larger than those of the zeolite of Comparative Example 1. Although both are the same MFI-type zeolites, the MFI-type zeolite using a plant-derived Si source has larger pores than the MFI-type zeolite using a mineral-based Si source, so it is considered to have characteristics different from those of zeolites produced from conventional mineral-based raw materials. Also, a plant-derived Si source (preferably, plant-derived silica waste liquid) is considered promising as a raw material for producing zeolites having new characteristics and functions.

[0232] <Examples 1 to 4> In the method for producing the inorganic porous material of the present technology, a plant-derived Si source (preferably, a plant-derived silica waste liquid) is preferable because it can reduce the production energy. Furthermore, as in Examples 1 to 4, when using a plant-derived silica waste liquid and / or a plant-derived ash as a raw material, there is a good advantage that zeolite can be produced without using an organic structure-directing agent. In addition, when using a plant-derived silica waste liquid as the first Si source, a wide variety of zeolites can be appropriately produced by utilizing other Si sources, Al sources, the amount of water, etc. In the production method of the present technology, by adjusting the Si / Al (molar ratio) and the water ratio of the gel composition, a wide variety of zeolites such as MFI-type zeolite, LTA-type zeolite, mordenite, etc. can be appropriately produced (see FIGS. 1 to 7).

[0233] Table 2 shows the Si / Al (gel) in the raw material, the Si / Al (product) in the obtained porous material, the specific surface area (S BET ) value by the nitrogen BET method, the external surface area (S EXT ) value obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method, the total pore volume (V total ) value obtained from the BET method, and the micropore volume (V micro ) value obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method. The external surface area (S EXT ) value obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method can be measured with reference to "Science of Adsorption; Seiichi Kondo, Tatsuo Ishikawa, Ikuo Abe; Maruzen Publishing, 2001, pages 48 to 50". Also, the total pore volume (V total ) value obtained from the BET method can be obtained from V total by the nitrogen BET method. Also, the micropore volume (V micro ) value obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method can be measured with reference to "Science of Adsorption; Seiichi Kondo, Tatsuo Ishikawa, Ikuo Abe; Maruzen Publishing, 2001, pages 48 to 50".

[0234] As shown in Table 2, the MFI-type zeolites (Examples 1 and 3) had an Si / Al(product) (mass ratio) of 10 to 20, and an (S BET ) value of 100 to 450 m 2 / g, an (S EXT ) value of 40 to 310 m 2 / g, a (V total ) value of 0.1 to 0.9 cm 3 / g, and the (V micro ) value was in the range of 0.2 to 0.9 cm 3 / g. Also, the mordenite (Example 2) had an Si / Al(product) (mass ratio) of 10 to 20, and an (S BET ) value of 100 to 300 m 2 / g, an (S EXT ) value of 10 to 50 m 2 / g, a (V total ) value of 0.1 to 0.5 cm 3 / g, and the (V micro ) value was in the range of 0.05 to 0.2 cm 3 / g. Also, the LTA-type zeolite (Example 4) had an Si / Al(product) (mass ratio) in the range of 0.1 to 1.5.

[0235] From the above, this technology has an average particle diameter of 50 nm or more (in the case of MFI type, 50 to 500 nm is preferable), the (S BET ) value of the specific surface area by the nitrogen BET method is 100 to 450 m 2 / g, the (S EXT ) value of the external surface area obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method is 20 to 400 m 2 / g, the (V total ) value of the total pore volume determined by the BET method is 0.1 to 1.0 cm 3 / g, and the (V micro ) value of the micropore volume obtained by analyzing the nitrogen adsorption evaluation data by the t-plot method is 0.01 to 0.2 cm 3 / g, and zeolites can be produced.

[0236]

Table 2

[0237] <Production Example D: Production of a recovered material containing an Si source obtained by alkali extraction> In the same manner as the method for producing the porous carbon material precursor described in Production Example A1, a porous carbon material precursor for alkali extraction was obtained, which is hereinafter referred to as rice husk carbon (RHC). <Production Examples D1-3: Alkali extraction solutions (ES-1, ES-2, ES-3)> As Production Example D1, 5 g of water (H2O) was added to 25 g of rice husk carbon, and the alkali solution containing this rice husk carbon was adjusted so that the molar ratio of NaOH / Si became 0.5. The adjusted alkali solution containing rice husk carbon was stirred at 80 °C for 24 hours to extract silica, and then filtered to obtain a silica extract (ES-1). As Production Example D2, a silica extract (ES-2) was obtained in the same manner as the above silica extract (ES-1), except that the alkali solution containing rice husk ash was adjusted so that the molar ratio of NaOH / Si became 1. As Production Example D3, a silica extract (ES-3) was obtained in the same manner as the above silica extract (ES-1), except that the alkali solution containing rice husk ash was adjusted so that the molar ratio of NaOH / fSi became 3. These were regarded as recovered materials containing the Si source obtained by alkali extraction (ES-1, ES-2, ES-3, respectively) and used as the first Si source composition. The Si amount of this "NaOH / Si" was calculated by the weight residue (42%) by TG (thermogravimetric analysis) × 90% (Si content rate of rice husk ash). TG was measured using Rigaku Thermo plus EVO II. The Si content rate of rice husk ash was measured by ICP emission analysis in the same manner as in Production Example B1, with rice husk being made into rice husk ash under the same conditions as in Production Example B1.

[0238]

Table 3

[0239] <Examples 5 and 6: Synthesis of LTA-Type Zeolite> Using the alkali extraction solution (ES-3) obtained in the above <Production Example D> as the first Si source composition as a raw material, LTA-type zeolite was synthesized. In Example 5, Al(OH)3 as an Al source was added to the alkali extraction solution (ES-3) which is the first Si source composition so that the gel composition (molar ratio) of the raw material becomes Si:Al:Na:H2O = 1:2:1.93:45 to obtain a raw material for a porous material. After stirring this raw material for the porous material at room temperature (20 to 30 °C) for 2 hours, hydrothermal synthesis was carried out in a static state at 90 °C for 24 hours under the atmosphere, followed by filtration, washing with water and ethanol at room temperature, and drying at 100 °C to synthesize zeolite, and this zeolite was used as the zeolite of Example 5. In Example 6, zeolite was synthesized in the same manner as in Example 5 except that water and Al(OH)3 as an Al source were added to the alkali extraction solution (ES-3) which is the first Si source composition so that the gel composition (molar ratio) of the raw material becomes Si:Al:Na:H2O = 1:2:1.93:55, and this zeolite was used as the zeolite of Example 6. Note that X-ray diffraction method (XRD), ICP analysis (ICP-AES), and atomic absorption analysis (AAs) were carried out according to <5. Each Measurement Method of the Present Technology>.

[0240] The XRD results of the zeolites of Examples 5 and 6 are shown in Fig. 8. LTA in Fig. 8 is the zeolite of Example 5, LTA-3 is the zeolite of Example 5, and LTA-4 is the zeolite of Example 6. SEM photographs of the zeolite of Example 5 (LTA-3) on the left side and the zeolite of Example 6 (LTA-4) on the right side of Fig. 9 are shown. In the zeolite of Example 5 (LTA-3) in Fig. 8, SOD was slightly observed in the black circle part, but the zeolite of Example 6 (LTA-4) was a pure-phase LTA-type zeolite. As shown in Fig. 9, LTA crystals were observed in both the zeolite of Example 5 (LTA-3) and the zeolite of Example 6 (LTA-4) on the right side, and their average particle diameters were 1 to 2 μm. Furthermore, the Si / Al ratios of the zeolites (LTA-3) in Example 5 and the zeolites (LTA-4) in Example 6 on the right were 0.88 and 0.90, respectively, both of which were less than 1. This was considered to be due to the presence of amorphous alumina. The Si / Al ratio was measured by ICP-AES analysis.

[0241] From this, using the first SI source composition and Al source of the alkaline extract ES-3 as raw materials and adjusting the gel composition ratio, the synthesis of LTA-type zeolite was successful. By using this alkaline extract as a raw material, it was no longer necessary to use a second Si source composition as a raw material as in the zeolite of Example 4, and LTA-type zeolite could be obtained without firing as in Example 4. Furthermore, when using a plant-derived first Si source composition as a raw material, it was confirmed that the Si / Al ratio and the amount of H2O in the synthesis gel affected the formation of LTA-type zeolite. Furthermore, the Si / Al ratio of LTA was approximately 0.89, and this ratio was considered to be affected by the remaining Al(OH)3.

[0242] <Examples 7 to 10: Synthesis of CHA-Type Zeolite> The alkaline extract (ES-1) obtained in the above <Production Example D> was used as the first Si source composition as a raw material to synthesize CHA-type zeolite. At this time, when synthesizing the zeolites in Examples 7 to 10 below, both cases of adding and not adding an organic structure-directing agent (OSDA) were carried out. When synthesizing the zeolites in Examples 7 to 10 below, 20 wt% of the seed crystals of CHA-type zeolite were added based on the mass of the raw material (liquid) of the porous material before hydrothermal synthesis. These seed crystals were synthesized according to the literature. The yield at the time of synthesis was determined by [(mass of the recovered solid) / (mass of the seed crystal + mass of SiO2 + mass of Al2O3) introduced into the aqueous solution containing the Al source and the alkali metal source] × 100 (%). This SiO2 and Al2O3 are the SiO2 and Al2O3 in the alkaline extract (ES-1).

[0243] In Example 7, an alkaline extraction solution (ES-1), which is the first Si source composition, was added to an aqueous solution containing Al(OH)₃ as the Al source, NaOH and KOH as the alkali metal sources, and water, such that the gel composition (molar ratio) of the raw materials was Si:Al:Na:K:H₂O = 1:0.05:0.6:0.1:100, to obtain the raw materials for the porous material. After stirring the raw materials for the porous material at room temperature (20 - 30 °C) for 2 hours, seed crystals of CHA-type zeolite were added and mixed, and then hydrothermal synthesis was carried out at 150 °C for 72 hours under the atmosphere. Thereafter, filtration was performed, and washing was carried out with water and ethanol, followed by drying at 100 °C to synthesize zeolite, and this zeolite was used as the zeolite of Example 7.

[0244] In Example 8, zeolite was synthesized in the same manner as in Example 7, except that an alkaline extraction solution (ES-1), which is the first Si source composition, was added to an aqueous solution containing Al(OH)₃ as the Al source, NaOH and KOH as the alkali metal sources, and water, such that the gel composition (molar ratio) of the raw materials was Si:Al:Na:K:H₂O = 1:0.05:0.8:0.1:100, and this zeolite was used as the zeolite of Example 8.

[0245] In addition, in Example 9, zeolite was synthesized in the same manner as in Example 7, except that the temperature of the hydrothermal synthesis was set to 160 °C, and this zeolite was used as the zeolite of Example 9. In addition, in Example 10, zeolite was synthesized in the same manner as in Example 8, except that the temperature of the hydrothermal synthesis was set to 160 °C, and this zeolite was used as the zeolite of Example 10. Note that X-ray diffraction method (XRD), ICP analysis (ICP-AES), and atomic absorption analysis (AAs) were carried out according to <5. Each measurement method of the present technology>.

[0246] From the XRD results of the zeolites of Examples 7 to 10, it was confirmed that all of these were CHA-type zeolites, and their yields were determined. The zeolite of Example 7 (CHA-1) contained mordenite (MOR type) in addition to the CHA type, and the yield was 43%. The zeolite (CHA-2) of Example 8 is a CHA-type zeolite, and the yield was 28%. The zeolite (CHA-3) of Example 9 is of the CHA type and also contains mordenite (MOR type), and the yield was 38%. When the molar ratio of Na in this Example 9 was 0.8, the CHA-type zeolite could be synthesized even without an OSDA. The zeolite (CHA-4) of Example 10 is a CHA-type zeolite, and the yield was 28%. When the molar ratio of Na in this Example 10 was 0.8, the CHA-type zeolite could be synthesized even without an OSDA.

[0247] <Examples 11 to 14: Synthesis of CHA-Type Zeolite> Using the obtained alkali extraction solution (ES-1) as the first Si source composition as a raw material, the CHA-type zeolite was synthesized. At this time, except that the molar ratio of Na was fixed at 0.8 and the molar ratio of Al was changed to 0.1 or 0.2, the zeolites of Examples 11 to 14 were synthesized in the same manner as in <Examples 7 to 10: Synthesis of CHA-Type Zeolite>. No organic structure-directing agent (OSDA) was added during this synthesis.

[0248] In Example 11, except that the alkali extraction solution (ES-1), which is the first Si source composition, was added to an aqueous solution containing Al(OH)3 as the Al source, NaOH and KOH as the alkali metal sources, and water so that the gel composition (molar ratio) of the raw material was Si:Al:Na:K:H2O = 1:0.1:0.8:0.1:100, zeolite was synthesized in the same manner as in Example 7 (hydrothermal temperature 150 °C), and this zeolite was used as the zeolite of Example 11.

[0249] In Example 12, zeolite was synthesized in the same manner as in Example 11 except that the alkaline extraction solution (ES-1), which is the first Si source composition, was added to an aqueous solution containing Al(OH)₃ as the Al source, NaOH and KOH as the alkali metal sources, and water so that the gel composition (molar ratio) of the raw materials was Si:Al:Na:K:H₂O = 1:0.1:0.8:0.2:100. The hydrothermal temperature was 150 °C, and this zeolite was used as the zeolite of Example 11.

[0250] In addition, in Example 13, zeolite was synthesized in the same manner as in Example 11 except that the hydrothermal synthesis temperature was 160 °C, and this zeolite was used as the zeolite of Example 13. In addition, in Example 14, zeolite was synthesized in the same manner as in Example 12 except that the hydrothermal synthesis temperature was 160 °C, and this zeolite was used as the zeolite of Example 14. Note that X-ray diffraction method (XRD), ICP analysis (ICP-AES), and atomic absorption spectrometry (AAs) were carried out according to <5. Each measurement method of the present technology>.

[0251] The XRD results of the zeolites of Examples 11 to 14 are shown in Fig. 10. Seed-CHA in Fig. 10 is the seed crystal of CHA-type zeolite, CHA-5 is the zeolite of Example 11, CHA-6 is the zeolite of Example 12, CHA-7 is the zeolite of Example 13, and CHA-8 is the zeolite of Example 14. SEM micrographs of the zeolites of Example 11 (CHA-type) for CHA-5, the zeolite of Example 12 (CHA-type) for CHA-6, the zeolite of Example 13 (CHA-type) for CHA-7, and the zeolite of Example 14 (CHA-type) for CHA-8 are shown at the upper left, upper right, lower left, and lower right of Fig. 11, respectively.

[0252] In the X-ray diffraction method (XRD), in Examples 11 to 14 of zeolites (CHA-5, CHA-6, CHA-7, and CHA-8) in FIG. 8, no MOR-type zeolite as an impurity phase was observed, and they were recognized as single-phase CHA-type zeolites. From the alkali extraction solution obtained above, OSDA-free synthesis of CHA-type zeolites could be performed. The yield of the CHA-type zeolite in Example 11 was 55%, the yield of the CHA-type zeolite in Example 12 was 87%, the yield of the zeolite in Example 13 was 51%, and the yield of the zeolite in Example 14 was 87%. By fixing the molar ratio of Na to 0.8 and increasing the molar ratio of Al to 0.1 and 0.2, the yield could be increased, but on the other hand, the crystallinity decreased. Also, it was confirmed that the synthesis temperature had almost no effect on the yield and crystallinity.

[0253] As shown in FIG. 11, for the zeolites of Examples 11 to 14, dish-shaped secondary particles (average particle diameter 2 to 4 μm) made of nanoparticles were observed. In the zeolites of Example 11 (CHA-5) and Example 13 (CHA-7) where the molar ratio of Al was 0.1, a small amount of MOR-type zeolite (acicular particles) was observed, but when the molar ratio of Al was 0.2, in the zeolites of Example 12 (CHA-6) and Example 14 (CHA-8), no MOR-type zeolite (acicular particles) was observed, and single-phase CHA-type zeolites were recognized. Furthermore, the Si / Al of the CHA-type zeolite (CHA-5) in Example 11, the CHA-type zeolite (CHA-6) in Example 12, the CHA-type zeolite (CHA-7) in Example 13, and the CHA-type zeolite (CHA-8) in Example 14 were 3.93, 3.26, 3.79, and 3.25, respectively. This Si / Al was measured by ICP-AES analysis.

[0254] <Production Example E: Characterization of the recovered product containing the Si source obtained by alkali extraction> In the same manner as the method for producing the porous carbon material precursor described in Production Example A1 above, a porous carbon material precursor for alkali extraction was obtained, which is hereinafter referred to as rice husk carbon (RHC). <Production Examples E1-4: Alkali extraction solution> As Production Examples E1 to E4, four raw materials were prepared by adding 5 g of water (H2O) to 25 g of rice husk charcoal. Four alkaline solutions containing rice husk charcoal were adjusted so that the molar ratio of NaOH / Si was 1, 2, 3, and 4, respectively. The four adjusted alkaline solutions containing rice husk charcoal were stirred at 80 °C for 24 hours to extract silica, and then filtered to obtain silica extracts Z-1 to Z-4. The amount of Si in this "NaOH / Si", the Si content rate of rice husk ash, etc. were calculated in the same manner as in the above <Production Example D>. The results of each of these alkaline extracts are shown in Table 4. As a result of adjusting the extraction of the Si source from rice husk ash so that the molar ratio (theoretical ratio) of NaOH / Si = 1 to 4, the higher the amount of NaOH used, the darker the color of the extract tended to be. The Si concentration and Si extraction efficiency were about the same, about 86%, regardless of the amount of NaOH used.

[0255]

Table 4

[0256] <Examples 15 to 18: LTA-type zeolite and FAU-type zeolite> Using the alkaline extracts (Z-1 to Z-4) obtained in the above <Production Example E> as the first Si source composition as the raw material, zeolite was synthesized. Note that X-ray diffraction method (XRD), ICP analysis (ICP-AES), and atomic absorption analysis (AAs) were performed by <5. Each measurement method of the present technology>.

[0257] In Example 15, Al(OH)3 as an Al source was added to the alkaline extract (Z-3) which is the first Si source composition so that the gel composition (molar ratio) of the raw material was Si:Al:Na:H2O = 1:2:3:55 to obtain a raw material for a porous material. After stirring this raw material for 2 hours at room temperature (20 to 30 °C), hydrothermal synthesis was carried out in a static state at 90 °C for 24 hours under the atmosphere, then filtered, washed with water and ethanol, and dried at 100 °C to synthesize zeolite, and this zeolite was used as the zeolite of Example 15. In Example 16, zeolite was synthesized in the same manner as in Example 5, except that water and Al(OH)3 as an Al source were added to the alkali extraction solution (Z-3), which is the first Si source composition, so that the gel composition (molar ratio) of the raw materials was Si:Al:Na:H2O = 1:(2 / 3):3:55. This zeolite was used as the zeolite of Example 16.

[0258] In Example 17, Al(OH)3 as an Al source was added to the alkali extraction solution (Z-4), which is the first Si source composition, so that the gel composition (molar ratio) of the raw materials was Si:Al:Na:H2O = 1:2:4:55 to obtain a raw material for a porous material. After stirring this raw material for the porous material at room temperature (20 - 30 °C) for 2 hours, hydrothermal synthesis was carried out in a static state at 90 °C for 24 hours under the atmosphere, followed by filtration, washing with water and ethanol, and drying at 100 °C to synthesize zeolite. This zeolite was used as the zeolite of Example 17. In Example 18, zeolite was synthesized in the same manner as in Example 5, except that water and Al(OH)3 as an Al source were added to the alkali extraction solution (Z-4), which is the first Si source composition, so that the gel composition (molar ratio) of the raw materials was Si:Al:Na:H2O = 1:(2 / 3):3:55. This zeolite was used as the zeolite of Example 18.

[0259] When the alkali extraction solutions (Z-1) and (Z-2), which are the first Si source compositions, were used as raw materials, even if the Si / Al ratio was adjusted by adding an Al source, the product was mainly amorphous. It was confirmed that using the alkali extraction solutions (Z-3) and (Z-4) with a NaOH / Si molar ratio of 3 - 4 was more efficient for producing LTA-type zeolite and FAU-type zeolite. Also, when producing zeolite using the alkali extraction from rice husk charcoal as the first Si source composition, which is the liquid raw material, it was considered desirable to keep the Na concentration used when obtaining the alkali extraction solution at a certain amount or more. Specifically, it is desirable to subject rice husk charcoal to alkali treatment so that the NaOH / Si molar ratio in the alkali extraction solution is 3 or more, and it was considered more desirable to carry out this alkali treatment using the adjustment of the NaOH / Si theoretical ratio.

[0260] Figure 12 shows the XRD diagrams of the zeolite (FAU type) of Example 16 in the upper section (Z-3-1.5) and the zeolite (LTA type) of Example 15 in the lower section (Z-3-0.5). The * in the upper section indicates the pattern of zeolite NaP (GIS type). Figure 13 shows the SEM photographs of the zeolite (FAU type) of Example 16 in the upper section (Z-3-1.5) and the zeolite (LTA type) of Example 15 in the lower section (Z-3-0.5). When an alkaline extraction solution (Z-3) with a NaOH / Si molar ratio of 3 was used as a raw material and the Si / Al ratio was adjusted to 0.5 with an Al source, zeolite A (LTA type) could be obtained (Example 15). When the Si / Al ratio was adjusted to 1.5 with an Al source, zeolite X (FAU type) could be obtained (Example 16). Thus, it was confirmed that almost pure zeolites (LTA type and FAU type) could be obtained in Example 15 and Example 16 where the NaOH / Si molar ratio was set to 3, respectively. Also, it was considered that a certain amount of Na or more was necessary for the formation of zeolite. In addition, it was confirmed that the zeolite of Example 16 contained a trace amount of zeolite NaP (GIS type), suggesting that GIS type zeolite can be produced by using an alkaline extraction solution.

[0261] Figure 14 shows the XRD diagrams of the zeolite (FAU type) of Example 17 in the upper section (Z-4-1.5) and the zeolite (LTA type) of Example 18 in the lower section (Z-4-0.5). The * in the upper section indicates the pattern of zeolite NaP (GIS type). The ◇ in the upper and lower sections indicates the pattern of sodalite (SOD type). Figure 15 shows the SEM photographs of the zeolite (FAU type) of Example 18 in the upper section (Z-4-1.5) and the zeolite (LTA type) of Example 15 in the lower section (Z-3-0.5). When using an alkaline extraction solution (Z-4) with a molar ratio of NaOH / Si = 4 as a raw material and adjusting the Si / Al ratio to 0.5 with an Al source, zeolite A (LTA type) can be obtained (Example 17). When adjusting the Si / Al ratio to 1.5 with an Al source, zeolite X (FAU type) could be obtained (Example 18). In Examples 17 and 18 where the molar ratio of NaOH / Si was set to 4, the formation of sodalite (SOD type) was also observed. It was considered that this was because the base concentration was too high, and it was thought that reducing this alkali concentration would make it easier to produce pure zeolite LTA type and FAU type. It was confirmed that the zeolite in Example 18 contained a trace amount of zeolite NaP (GIS type), suggesting that GIS type zeolite can be produced by using an alkaline extraction solution.

[0262] According to Examples 15 to 18, it was considered that the zeolite structure generated by using the alkaline extraction solution from rice husk charcoal as the first Si source composition as a raw material depends on the Si / Al molar ratio of the gel composition at the time of charging. It was confirmed that when the Si / Al molar ratio is 0.5, zeolite A (LTA type) is likely to be generated, and when the Si / Al molar ratio is 1.5, zeolite X (FAU type) is likely to be generated.

Claims

1. A method for producing a porous material, which uses at least a first Si source composition that is a plant-derived Si source and an Al source as raw materials, and contains Si and Al, wherein the first Si source composition is a Si source recovered by subjecting a plant-derived raw material to carbonization treatment and then performing a treatment for recovering the Si source, and is a method for producing a porous material.

2. The method for producing a porous material according to Claim 1, further using a second Si source composition as a raw material.

3. The method for producing a porous material according to Claim 1 or 2, wherein the treatment for recovering the Si source is a treatment by alkali extraction performed by adjusting the NaOH / Si molar ratio (theoretical ratio).

4. The method for producing a porous material according to Claim 1 or 2, wherein the first Si source composition has a silicon content of 10 g / L or more.

5. The method for producing a porous material according to Claim 1 or 2, wherein the Si / Al composition ratio (mass ratio) of the first Si source composition is 1 to 300.

6. The method for producing a porous material according to Claim 2, wherein the second Si source is a mineral-derived Si source and / or a plant-derived Si source.

7. The method for producing a porous material according to Claim 2, wherein the second Si source composition is a treated product obtained by decarbonizing a plant-derived raw material.

8. The method for producing a porous material according to Claim 2, wherein the second Si source composition is plant-derived ash.

9. The method for producing a porous material according to Claim 2, wherein the second Si source composition is a Si source recovered by subjecting a plant-derived raw material to carbonization treatment and then performing a treatment for recovering the Si source.

10. The method for producing a porous material according to Claim 1 or 2, further using an organic structure-directing agent as a raw material.

11. The method for producing a porous material according to Claim 1, wherein a heat treatment is performed on a mixture of the first Si source composition that is a plant-derived Si source and the Al source.

12. The method for producing a porous material according to Claim 11, wherein the mixture further contains a second Si source composition.

13. The method for producing a porous material according to Claim 11 or 12, wherein the heat treatment is hydrothermal synthesis.

14. The method for producing a porous material according to Claim 11 or 12, wherein the heat treatment is in the order of aging and then hydrothermal synthesis.

15. The method for producing a porous material according to Claim 1 or 2, wherein the first Si source composition is an aqueous solution recovered by removing silica from a plant-derived raw material containing silica.

16. The method for producing a porous material according to claim 1 or 2, wherein the porous material is zeolite.

17. The method for producing a porous material according to claim 1 or 2, wherein the plant is a Gramineae plant.

18. A method for producing a porous material containing Si and Al, using at least as raw materials a first Si source composition which is a plant-derived Si source, a second Si source composition, and an Al source.

19. The method for producing a porous material according to claim 18, wherein the second Si source is a mineral-derived Si source and / or a plant-derived Si source.

20. The method for producing a porous material according to claim 18, wherein the second Si source composition is a processed product obtained by decarbonizing a plant-derived raw material.

21. The method for producing a porous material according to claim 18, wherein the second Si source composition is plant-derived ash.

22. The method for producing a porous material according to claim 18, wherein the second Si source composition is a Si source recovered at this time by performing a process of recovering a Si source after carbonizing a plant-derived raw material.

23. A porous material obtained by the method for producing a porous material according to claim 1 or 18.

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