Porous silicon oxide-clay composite material, water purifying agent comprising porous silicon oxide-clay composite material, soil powder comprising porous silicon oxide-clay composite material, and method for producing porous silicon oxide-clay composite material

Abstract

A porous silicon oxide-clay composite material in which the content of a clay material with respect to the sum of the clay material and a silicon oxide [[clay material / (clay material + silicon oxide)] * 100] is 1-10% by weight, and the specific surface area of the porous silicon oxide-clay composite material is 1080 m2 / g or more.

Description

Technical Field

[0001] The present invention relates to a porous silicon oxide-clay composite material, a water purifying agent containing the porous silicon oxide-clay composite material, a powder for soil containing the porous silicon oxide-clay composite material, and a method for producing the porous silicon oxide-clay composite material. Background Art

[0002] Porous silicon oxides are known to be used for adsorbing gases, water, etc. In order to improve the adsorption performance of porous silicon oxides, it is necessary to increase the specific surface area, but there is a limit to this.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent Laid-Open No. 2008-137859 Summary of the Invention

[0006] One aspect of the present invention is a porous silicon oxide-clay composite material, in which the content ratio of the clay material relative to the sum of the clay material and the silicon oxide [(clay material / (clay material + silicon oxide))×100] is 1% to 10% by weight, and the specific surface area of the porous silicon oxide-clay composite material is 1080 m 2 / g or more.

[0007] Another aspect of the present invention is a water purifying agent containing the above-mentioned porous silicon oxide-clay composite material.

[0008] Another aspect of the present invention is a powder for soil containing the above-mentioned porous silicon oxide-clay composite material.

[0009] Another aspect of the present invention is a method for producing a porous silicon oxide-clay composite material, including: i) a mixing step in which a first solution containing a clay material, an alkali, and water is mixed with a second solution containing a silicon oxide source, an acid, water, and optionally a clay material; and ii) a drying step in which the mixed solution obtained by mixing in the mixing step is heated and dried, wherein the sum of the weight of the silicon oxide source and the weight of the acid contained in the mixed solution relative to the sum of the weight of the clay material and the weight of the alkali [(weight of silicon oxide source + weight of acid) / (weight of clay material + weight of alkali)] is 52 to 300. Brief Description of the Drawings

[0010] Figure 1 is a schematic view showing an example of the method for producing the porous silicon oxide-clay composite material of the present invention. Detailed Description

[0011] ​Hereinafter, embodiments of the present invention (hereinafter referred to as "the present embodiment") will be described. The following present embodiment is an example for explaining the present invention and is not intended to limit the present invention to the following content. The present invention can be implemented with appropriate modifications within the scope of its gist.

[0012] <Porous silicon oxide-clay composite material>

[0013] In the porous silicon oxide-clay composite material of the present embodiment, the content ratio of the clay material with respect to the sum of the clay material and the silicon oxide [[clay material / (clay material + silicon oxide)] × 100] is 1% to 10% by weight, and the specific surface area is 1080 m 2 / g or more of the porous silicon oxide-clay composite material.

[0014] First, the components of the porous silicon oxide-clay composite material of the present embodiment will be described.

[0015] The clay material is a natural or artificial swelling clay mineral. Examples of the swelling clay mineral include bentonite, saponite, humite, and lithium montmorillonite. These clay materials can be contained alone or in combination. In addition, in this specification, the clay material refers to the clay material in a dry state without moisture.

[0016] The silicon oxide is, for example, a silicon compound such as silica which is a hydrolysis product of an alkoxysilane. The alkoxysilane serving as the silicon oxide source is, for example, tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, dimethyldimethoxysilane, diethylethoxysilane, hydroxyethyltrimethoxysilane, hydroxyethyldimethylmethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 2-methoxyethyltriethoxysilane, phenyltriethoxysilane, p-hydroxyphenyltrimethoxysilane, p-hydroxybenzyltriethoxysilane, p-mercaptobenzyltripropoxysilane, etc., and preferably tetramethoxysilane and tetraethoxysilane. In addition, as the silicon oxide source, water glass can also be used.

[0017] Generally, in clay minerals, the basic structure is composed of three nanosheets in which a nanosheet of AlO6 or MgO6 having a negative charge is sandwiched between nanosheets of SiO4 having a negative charge in a tetrahedron. Regarding this basic structure as one layer, multiple layers of this basic structure are stacked. Exchangeable cations such as potassium ions exist between the layers, and each layer is electrostatically bonded to each other through these cations. However, since the bonding between the layers is weak, it is easily swollen or exfoliated in water. However, if the silicon oxide is mixed with the clay material, the silicon oxide infiltrates into the layers of the clay mineral, and the three-dimensional structure of the clay mineral can be maintained via the silicon oxide.

[0018] The content rate of the clay material relative to the silicon oxide is 1% to 10% by weight. If this content rate is too high, the clay material cannot be uniformly mixed in the sample. If this content rate is too low, it is difficult to increase the specific surface area. From this perspective, the lower limit of this content rate is preferably 1.1%, more preferably 1.2%, and further preferably 1.25%. The upper limit of this content rate is preferably 9%, more preferably 8%, and further preferably 7%.

[0019] In addition, known components such as colorants, decolorants, deodorants, viscosity regulators, pH regulators, and fertilizer components can be added in appropriate amounts according to the use. In addition, not limited to the above components, other components can also be added within the range of obtaining the effects of the porous silicon oxide-clay composite material of this embodiment.

[0020] Next, the physical properties of the porous silicon oxide-clay composite material of this embodiment will be described.

[0021] The specific surface area of the porous silicon oxide-clay composite material of this embodiment is 1080 m 2 / g or more. The lower limit of the specific surface area is preferably 1100 m 2 / g, more preferably 1150 m 2 / g, and further preferably 1200 m 2 / g. The upper limit of the specific surface area can be, for example, 2000 m 2 / g, or can also be 1950 m 2 / g. By having such a high specific surface area, high adsorption and water retention properties can be achieved.

[0022] The pore size of the porous silicon oxide-clay composite material of this embodiment is 2 to 30 nm. The lower limit of the pore size is preferably 2.5 nm, more preferably 3 nm, and further preferably 3.5 nm. The upper limit of the pore size is preferably 20 nm, more preferably 15 nm. By setting the pore size within this range, various molecules can be adsorbed in the pores and liquids can be absorbed by capillary condensation.

[0023] The cation exchange capacity (CEC) of the porous silicon oxide-clay composite material of this embodiment is 10 meq / 100 g or more. The lower limit of the CEC is preferably 15 meq / 100 g, more preferably 16 meq / 100 g, and further preferably 17 meq / 100 g. The upper limit of the CEC is, for example, 120 meq / 100 g, preferably 110 meq / 100 g. By having such a high CEC, the occlusion and slow release properties of cationic substances can be improved.

[0024] The water absorption rate of the porous silicon oxide-clay composite material of this embodiment is 50% or more. The lower limit of the water absorption rate is preferably 55%, more preferably 60%, and further preferably 65%. The upper limit of the water absorption rate can be, for example, 410% or 400%. By having such a high water absorption rate, high water retention can be achieved.

[0025] The methylene blue adsorption rate of the porous silicon oxide-clay composite material of this embodiment is 60% or more. The lower limit of the methylene blue adsorption rate is preferably 70%, more preferably 80%, and further preferably 85%. The upper limit of the methylene blue adsorption rate can be, for example, 99.6% or 99%. By having such a high methylene blue adsorption rate, high adsorption can be achieved.

[0026] The total pore volume of the porous silicon oxide-clay composite material of this embodiment is 0.7 cm 3 / g or more. The lower limit of the total pore volume is preferably 0.8 cm 3 / g, more preferably 1 cm 3 / g, and further preferably 1.5 cm 3 / g. The upper limit of the total pore volume can be, for example, 4.1 cm 3 / g or 3 cm 3 / g. By having such a high total pore volume, high water retention and adsorption can be achieved.

[0027] <Uses of the Porous Silicon Oxide-Clay Composite Material>

[0028] Water purifying agent

[0029] The water purifying agent of this embodiment contains the above-mentioned porous silicon oxide-clay composite material. Such a water purifying agent can adsorb and remove impurities when mixed with unpurified water such as muddy water due to its high adsorption.

[0030] Powder for soil

[0031] The powder for soil of this embodiment contains the above-mentioned porous silicon oxide-clay composite material. Such a powder for soil has high water retention, so it can retain water even with a small amount of rain, and can be used for cultivating plants in dry regions with little rain, on the roofs of buildings, etc. In addition, if fertilizer components such as phosphoric acid are used as raw materials, it can also become a nutrient for the soil.

[0032] In addition, in addition to the above uses, it can also be used for deodorants, desiccants, horticultural sponges, sand for pet toilets, wall materials, water-retaining paving for roads, water quality purifying agents, soil purifying agents, waste gas treatment, oil adsorbents, recovery of rare earths or radioactive substances, food additives, heat-insulating materials, sound-insulating materials, heat-resistant materials, humidity regulators, drug delivery carriers, etc.

[0033] <Method for manufacturing porous silicon oxide-clay composite material>

[0034] As Figure 1 shown, the method for manufacturing a porous silicon oxide-clay composite material according to this embodiment includes:

[0035] i) A mixing step, in which a first solution containing a clay material, an alkali, and water is mixed with a second solution containing a silicon oxide source, an acid, water, and optionally a clay material; and

[0036] ii) A drying step, in which the mixed solution obtained by mixing in the above mixing step is heated and dried.

[0037] i) Mixing step

[0038] In the mixing step, first, a first solution containing a clay material, an alkali, and water, and a second solution containing a silicon oxide source, an acid, water, and optionally a clay material are prepared. Then, the alkaline first solution is mixed with the acidic second solution. The alkali contained in the first solution is preferably added to the first solution immediately before mixing the first solution and the second solution.

[0039] The clay material is a natural or artificial swellable clay mineral, and bentonite, talc, humite, lithium montmorillonite, etc. can be used. These clay materials can be contained alone or in combination. The clay material is preferably a dry clay material without moisture.

[0040] The clay material is introduced into the mixed solution at a content rate of 0.1% to 10% by weight. The lower limit of the content rate of the clay material relative to the mixed solution is preferably 0.11%, more preferably 0.12%, and further preferably 0.13%. The upper limit of the content rate of the clay material relative to the mixed solution is preferably 9%, more preferably 8%, and further preferably 7%. It should be noted that the clay material can be introduced in its entirety only in the first solution, or can be introduced into the first solution and the second solution in divided amounts.

[0041] Water is appropriately divided and introduced into the first solution and the second solution at a content rate of 20% to 95% by weight relative to the mixed solution. The lower limit of the content rate of water relative to the mixed solution is preferably 30%, more preferably 40%, and further preferably 50%. The upper limit of the content rate of water relative to the mixed solution is preferably 90%, more preferably 85%, and further preferably 80%.

[0042] The alkali is a substance introduced into the first solution to improve the porosity of the silicon oxide, and is preferably introduced in the form of an aqueous solution.

[0043] The base is an alkylamine such as methylamine, ethylamine, dimethylamine, diethylamine, trimethylamine, triethylamine, ammonia, sodium hydroxide, potassium hydroxide, etc., and ammonia is preferred. The base is introduced into the first solution at a content rate of 0.05% to 0.3% by weight. The lower limit of the content rate of the base relative to the first solution is preferably 0.06%, more preferably 0.07%, and further preferably 0.08%. The upper limit of the content rate of the base relative to the first solution is preferably 0.2%, more preferably 0.15%, and further preferably 0.1%.

[0044] The base is preferably added after adding the clay material to water. Moreover, it is preferred to perform the stirring step before adding the base, that is, in a state where the clay material has been added to water.

[0045] The stirring in the stirring step is carried out for 1 to 72 hours. The lower limit of the stirring time is preferably 2 hours, more preferably 3 hours, and further preferably 4 hours. The upper limit of the heating time is preferably 70 hours, more preferably 50 hours, and further preferably 30 hours. The stirring can be carried out at room temperature.

[0046] The silicon oxide source is introduced into the second solution at a content rate of 30% to 90% by weight. The lower limit of the content rate of the silicon oxide source relative to the second solution is preferably 40%, more preferably 45%, and further preferably 50%. The upper limit of the content rate of the silicon oxide source relative to the second solution is preferably 85%, more preferably 80%, and further preferably 78%.

[0047] The silicon oxide source is an alkoxysilane, etc., such as tetramethoxysilane, tetraethoxysilane, trimethylmethoxysilane, dimethyldimethoxysilane, diethylethoxysilane, hydroxyethyltrimethoxysilane, hydroxyethyldimethylmethoxysilane, 3-aminopropyldimethylmethoxysilane, 3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 2-methoxyethyltriethoxysilane, phenyltriethoxysilane, p-hydroxyphenyltrimethoxysilane, p-hydroxybenzyltriethoxysilane, p-mercaptobenzyltripropoxysilane, etc., and tetramethoxysilane and tetraethoxysilane are preferred. These silicon oxide sources can be used alone or in combination.

[0048] The acid is a substance introduced into the second solution as a catalyst for hydrolyzing the silicon oxide source, and is preferably introduced in the form of an aqueous solution.

[0049] The acids are hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid, oxalic acid, carbonic acid, etc., and phosphoric acid is preferred. The acid is introduced at a content rate of 0.03% to 0.2% by weight based on the second solution. The lower limit of the content rate of the acid based on the second solution is preferably 0.04%, more preferably 0.05%, and still more preferably 0.06%. The upper limit of the content rate of the acid based on the second solution is preferably 0.19%, more preferably 0.18%, and still more preferably 0.17%.

[0050] The sum of the weight of the silicon oxide source and the weight of the acid contained in the mixed solution is 52 to 300 with respect to the sum of the weight of the clay material and the weight of the base [(weight of silicon oxide source + weight of acid) / (weight of clay material + weight of base)]. The lower limit of this value is preferably 53, more preferably 54, and still more preferably 55. The upper limit of this value is preferably 290, more preferably 280, and still more preferably 270. By setting it within such a numerical range, a high specific surface area can be achieved.

[0051] After mixing, it can be directly left to age. The aging temperature is 20 to 100 °C. The lower limit of the aging temperature is preferably 21 °C, more preferably 22 °C, and still more preferably 23 °C. The upper limit of the aging temperature is preferably 90 °C, more preferably 80 °C, and still more preferably 70 °C. The aging time is 1 to 72 hours. The lower limit of the aging time is preferably 2 hours, more preferably 3 hours, and still more preferably 4 hours. The upper limit of the aging time is preferably 70 hours, more preferably 50 hours, and still more preferably 30 hours.

[0052] ii) Drying process

[0053] The drying temperature in the drying process is 20 to 100 °C. The lower limit of the drying temperature is preferably 23 °C, more preferably 30 °C, and still more preferably 40 °C. The upper limit of the drying temperature is preferably 100 °C, more preferably 90 °C, and still more preferably 80 °C.

[0054] The drying time in the drying process is 5 to 168 hours. The lower limit of the drying time is preferably 6 hours, more preferably 7 hours, and still more preferably 8 hours. The upper limit of the drying time is preferably 160 hours, more preferably 150 hours, and still more preferably 140 hours.

[0055] After drying, the porous silicon oxide - clay composite material can be made into powder by pulverizing the obtained dried product.

[0056] Examples

[0057] Next, examples and comparative examples of the present invention will be described. It should be noted that the present invention is not limited to these.

[0058] <Manufacture of porous silicon oxide - clay composite material>

[0059] Prepare an alkaline first solution containing the components shown in Table 1 described later and an acidic second solution containing the components shown in Table 2. Then, the first solution and the second solution were mixed at room temperature for 1 minute until they became uniform, and then aged at 70°C for 1 day. Then, dried at 70°C for 1 day, and the dried product was crushed after drying to obtain a powder of a porous silicon oxide-clay composite material. It should be noted that tetraethoxysilane uses a product manufactured by Tokyo Chemical Industry Co., Ltd., and bentonite, saponite, hectorite, and stevensite use products manufactured by Kunimine Industries.

[0060] <Physical Property Evaluation>

[0061] Determination of the content of clay material relative to silicon oxide (clay in product: wt%)

[0062] It is calculated by (total clay material weight) / (total clay material weight+SiO2 weight obtained from added TEOS)×100.

[0063] Determination of specific surface area, pore size and total pore volume

[0064] The N2 gas adsorption test was carried out, and the specific surface area, pore size, and total pore volume were calculated using the BET method.

[0065] Cation Exchange Capacity (CEC) Determination

[0066] The sample was cation exchanged three times with ammonium acetate, washed three times with alcohol, and ammonium ions were extracted three times with KCl. The extract was then filtered with filter paper. The ammonium ions in the extract were quantified by the formaldehyde method (holmol method) to calculate the cation exchange capacity per 100 g of the sample.

[0067] Water absorption determination

[0068] Make 7 holes of about 2 mm at the bottom of the metal container and put a glass fiber filter in it. Add water to the metal basin, let the container stand for 60 minutes, and measure the weight after water absorption. Put 3g of sample in, let it stand for 60 minutes, and measure the weight after water absorption. The water absorption rate is calculated by (weight of sample after water absorption - weight of water absorption without sample - sample weight) / sample weight × 100.

[0069] Methylene blue adsorption assay

[0070] 0.1 g of the sample was added to 100 mL of a 0.05 mM methylene blue aqueous solution and stirred for 1 day. The solution was filtered through a PTFE needle filter and the absorbance was measured. The amount of methylene blue adsorption was calculated from the decrease rate relative to the blank absorbance.

[0071] Regarding the alkaline solution (first solution) in Table 1, the acidic solution (second solution) in Table 2, and the mixed solution of the first solution and the second solution in Table 3, the compositions of each example and each comparative example are shown. In Table 4, the physical property values of each example and comparative example are shown for the product. It should be noted that tetraethoxysilane (TEOS) is used as the alkoxysilane in both the examples and comparative examples.

[0072] [Table 1]

[0073]

[0074] [Table 2]

[0075]

[0076] [Table 3]

[0077]

[0078] [Table 4]

[0079]

[0080] From the above confirmation, the porous silicon oxide-clay composites of each example have a high specific surface area, CEC, water absorption rate, methylene blue adsorption rate, and total pore volume.

Claims

1. A porous silicon oxide-clay composite material, wherein, by weight percentage, the content rate of the clay material relative to the sum of the clay material and the silicon oxide [[clay material / (clay material + silicon oxide)] × 100] is 1% to 10%; The specific surface area of the porous silicon oxide-clay composite material is 1080 m 2 / g or more.

2. A water purifying agent comprising the porous silicon oxide-clay composite material according to claim 1.

3. A powder for soil comprising the porous silicon oxide-clay composite material according to claim 1.

4. A method for manufacturing a porous silicon oxide-clay composite material, comprising: i) a mixing step in which a first solution containing a clay material, an alkali, and water is mixed with a second solution containing a silicon oxide source, an acid, water, and optionally the clay material; and ii) a drying step in which the mixed solution obtained by mixing in the mixing step is heated and dried, wherein the sum of the weight of the silicon oxide source and the weight of the acid contained in the mixed solution relative to the sum of the weight of the clay material and the weight of the alkali [(weight of silicon oxide source + weight of acid) / (weight of clay material + weight of alkali)] is 52 to 300.

5. The manufacturing method of the porous silicon oxide-clay composite material according to claim 4, wherein, The clay material is a swelling clay mineral.

6. The method for manufacturing a porous silicon oxide-clay composite material according to claim 5, wherein, The swelling clay mineral is any one or more selected from bentonite, saponite, humite, and hectorite.

7. The manufacturing method of the porous silicon oxide-clay composite material according to any one of claims 4 to 6, wherein, The content rate of the clay material relative to the mixed solution is 0.1% to 10% by weight percentage.

8. The method for manufacturing a porous silicon oxide-clay composite material according to any one of claims 4 to 7, wherein, The alkali is ammonia.

9. The manufacturing method of the porous silicon oxide-clay composite material according to any one of claims 4 to 8, wherein, The content rate of the alkali relative to the first solution is 0.05% to 0.3% by weight.

10. The manufacturing method of the porous silicon oxide-clay composite material according to any one of claims 4 to 9, wherein, The silicon oxide source is an alkoxysilane.

11. The method for manufacturing a porous silicon oxide-clay composite material according to any one of claims 4 to 10, wherein, The content rate of the silicon oxide source relative to the second solution is 30% to 90% by weight percentage.

12. The manufacturing method of the porous silicon oxide-clay composite material according to any one of claims 4 to 11, wherein, The acid is phosphoric acid.

13. The manufacturing method of the porous silicon oxide-clay composite material according to any one of claims 4 to 12, wherein, The content rate of the acid relative to the second solution is 0.03% to 0.2% by weight percentage.

14. The method for manufacturing a porous silicon oxide-clay composite material according to any one of claims 4 to 13, wherein, in the mixing step, the first solution is prepared by adding the alkali after mixing the clay material and the water, before adding the alkali, a stirring step of stirring the clay material and the water is performed.

15. The manufacturing method of the porous silicon oxide-clay composite material according to claim 14, wherein, The stirring time in the stirring step is 1 to 72 hours.

16. The manufacturing method of the porous silicon oxide-clay composite material according to any one of claims 4 to 15, wherein, The heating temperature in the drying step is 20 to 100 °C.

17. The method for manufacturing a porous silicon oxide-clay composite material according to any one of claims 4 to 16, wherein, The drying time in the drying step is 5 to 168 hours.

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