Method for synthesizing adsorbent and adsorbent synthesis device

Abstract

To provide a method for synthesizing an adsorbent and an adsorbent synthesis device that allow adjustment of the adsorbent to an optimal size for a filter to be used, even in cases where only fine crystals can be formed in the adsorbent.SOLUTION: A method for synthesizing an adsorbent is characterized by including steps of: reacting a first stock solution L1 and a second stock solution L2 in the presence of seed crystals M so that a reaction product is deposited around the seed crystals to yield a crystallized product; and classifying the crystallized product to obtain, as the adsorbent, a crystallized product having a size not less than a predetermined size. An adsorbent synthesis device comprises: a first container 2 containing the first stock solution, a second container 3 containing the second stock solution, a third container 4 containing the seed crystals, and a reaction container 5 configured to mix the first stock solution, the second stock solution, and the seed crystals, and to cause the first stock solution and the second stock solution to react in the presence of the seed crystals so that the reaction product is deposited around the seed crystals; and a circulation mechanism 6 that removes unreacted first and second stock solutions from the reaction container and returns them into the reaction container.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for synthesizing an adsorbent. [Background technology]

[0002] Many metals exist in the form of ions in liquids in the environment, but if these metals are ingested into the human body, they can cause health problems. For example, there are known to be highly lethal metals such as heavy metals, and radioactive metals that accumulate in the body and cause health problems due to internal exposure.

[0003] When radioactive cesium and radioactive strontium (hereinafter referred to as "radioactive materials") are ingested into the human body, they accumulate and cause internal radiation exposure or health problems due to simple ingestion of heavy metals. Therefore, when discharging radioactive materials into the environment, prior treatment of radioactive materials and heavy metals using absorbents, etc. is extremely important in order to prevent the spread of contamination.

[0004] Various techniques have been investigated for removing radioactive materials. For example, Non-Patent Document 1 listed below describes the adsorption of radioactive cesium by ammonium phosphomolybdate. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] https: / / unit.aist.go.jp / georesenv / information / 20150917 / TechRep_Cs_Monitoring_Water.pdf Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, adsorbents such as the above-mentioned ammonium phosphomolybdate can be crystallized by, for example, a chemical reaction. However, the crystals of ammonium phosphomolybdate or the like produced by this chemical reaction are very fine and may slip through the gaps of a filter. In other words, in the case of an adsorbent made of fine crystals, even if it adsorbs the substance to be adsorbed, it is often difficult to filter it through a filter, making it difficult to remove the substance from the solution.

[0007] In view of the above problems, the present invention aims to provide an adsorbent synthesis method and an adsorbent synthesis apparatus that can adjust the size of an adsorbent that can only form fine crystals to be optimal for the filter to be used. [Means for solving the problem]

[0008] A method for synthesizing an adsorbent according to one aspect of the present invention that solves the above-mentioned problems includes the steps of reacting a first stock solution and a second stock solution in the presence of seed crystals to precipitate a reaction product around the seed crystals, thereby obtaining a crystallized product, and classifying the crystallized product to obtain crystallized products of a predetermined size or larger as an adsorbent.

[0009] In addition, in this respect, although not limited thereto, the adsorbent is preferably at least one of metal ferrocyanide, heteropolyacid, and metal phosphate.

[0010] Furthermore, in this aspect, although not limited thereto, it is preferable that the first stock solution is a solution containing at least one of cobalt chloride, ferric chloride, nickel chloride, manganese chloride, copper chloride, zinc chloride, and phosphotungstic acid, phosphomolybdic acid, zirconium chloride oxide, titanium chloride, cerium sulfate, tin chloride, and antimony chloride, and that the second stock solution is a solution containing potassium ferrocyanide and at least one of ammonium hydrogen carbonate, ammonium chloride, urea, potassium chloride, phosphoric acid, and sodium dihydrogen phosphate.

[0011] Furthermore, in this respect, although not limited thereto, the adsorbent is preferably at least one of cobalt ferrocyanide, iron ferrocyanide, nickel ferrocyanide, manganese ferrocyanide, copper ferrocyanide, zinc ferrocyanide, ammonium phosphotungstate, potassium phosphotungstate, ammonium phosphomolybdate, potassium phosphomolybdate, zirconium phosphate, titanium phosphate, cerium phosphate, tin phosphate, and antimony phosphate.

[0012] In addition, in this respect, although not limited thereto, it is preferable to have a step of contacting the crystallized product having a predetermined size or less in the presence of a first stock solution and a second stock solution, thereby precipitating a reaction product around the seed crystal, thereby obtaining a crystallized product having a predetermined size or more.

[0013] In addition, in this respect, although not limited thereto, the predetermined size is preferably an average particle size of 10 μm or more.

[0014] Another aspect of the present invention provides an adsorbent synthesis apparatus comprising a first container for accommodating a first stock solution, a second container for accommodating a second stock solution, a third container for accommodating a seed crystal, and a reaction container for mixing the first stock solution, the second stock solution, and the seed crystal and reacting the first stock solution and the second stock solution in the presence of the seed crystal to precipitate a reactant around the seed crystal, and further comprising a circulating mechanism for removing unreacted first stock solution and second stock solution from the reaction container and returning them to the reaction container.

[0015] In addition, in this respect, although not limited thereto, it is preferable that the reaction vessel is provided with a circulating flow forming member for forming a circulating flow within the reaction vessel. [Effects of the Invention]

[0016] As described above, the present invention can provide an adsorbent synthesis method and adsorbent synthesis apparatus that can adjust the size of an adsorbent that can only form fine crystals to be optimal for the filter to be used. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a diagram showing an outline of an adsorbent synthesis apparatus according to an embodiment. [Figure 2] FIG. 2 is a diagram showing an image of a cross section of an adsorbent according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention can be embodied in many different forms, and is not limited to the specific examples described in the following embodiments and examples.

[0019] 1 is a schematic diagram of an adsorbent synthesis apparatus (hereinafter referred to as "the apparatus") 1 according to this embodiment. As shown in the figure, the apparatus 1 includes a first container 2 that contains a first stock solution L1, a second container 3 that contains a second stock solution L2, a third container 4 that contains a seed crystal M, and a reaction container 5 that mixes the first stock solution L1, the second stock solution L2, and the seed crystal M and reacts the first stock solution L1 and the second stock solution L2 in the presence of the seed crystal M to precipitate a reaction product around the seed crystal M, and also includes a circulating mechanism 6 that removes unreacted first stock solution L1 and second stock solution L2 from the reaction container 5 and returns them to the reaction container 5.

[0020] The present apparatus 1 also includes a recovery vessel 7 for recovering the adsorbent synthesized in the reaction vessel 5.

[0021] With the above-described configuration, the present device 1 can provide an adsorbent synthesis method and an adsorbent synthesis device that can adjust the size of an adsorbent that can only form fine crystals to be optimal for the filter to be used, even if the adsorbent can only form fine crystals. The details of this will be described in detail below.

[0022] First, the present apparatus 1 has a first container 2 that contains a first stock solution L1 as described above. Here, a "stock solution" is a liquid containing a substance used for a reaction, which can precipitate a reactant by mixing with other stock solutions. Furthermore, the term "first" here is merely an ordinal number used to distinguish it from other stock solutions, and does not itself have any technical meaning.

[0023] In the present apparatus 1, the first stock solution is not limited as long as it can achieve the effects of the present invention, but is preferably at least one of cobalt chloride, ferric chloride, nickel chloride, manganese chloride, copper chloride, zinc chloride, and phosphotungstic acid, phosphomolybdic acid, zirconium chloride oxide, titanium chloride, cerium sulfate, tin chloride, and antimony chloride. However, the first stock solution is not limited as long as it can react with the second stock solution described below, and it is also possible to replace the first stock solution with the second stock solution described below.

[0024] Furthermore, as described above, the "container" in this device 1 is not limited to a specific material, and various shapes and capacities can be used as long as it is capable of containing and retaining the concentrate. While the material is not particularly limited, metals and resins are suitable. Examples of metals include stainless steel, aluminum alloys, titanium alloys, and nickel alloys, while examples of resins include, but are not limited to, polyethylene, ABS, and polytetrafluoroethylene (PTFE). Furthermore, while the term "first" is used for the container of this device 1, this is the same as the use of the term for the concentrate described above. It is merely an ordinal number used to distinguish it from other containers and does not itself have any technical meaning.

[0025] Furthermore, as described above, the present apparatus 1 has a second container 3 that contains a second stock solution L2. Here, the "stock solution" is the same as described above, and is a liquid containing a substance used for a reaction, which can precipitate a reaction product by mixing with another stock solution (specifically, the first stock solution). Furthermore, the term "second" here is merely an ordinal number used to distinguish it from other stock solutions (specifically, the first stock solution), and does not itself have any technical meaning.

[0026] In the present apparatus 1, the second stock solution is not limited as long as it can achieve the effects of the present invention. However, when the first stock solution is used in the above example, it is preferably potassium ferrocyanide and at least one of ammonium bicarbonate, ammonium chloride, urea, potassium chloride, phosphoric acid, and sodium dihydrogen phosphate. This allows crystals to be precipitated by reacting the first and second stock solutions. That is, the adsorbent synthesized by the present apparatus 1 is preferably at least one of metal ferrocyanide, heteropolyacid, and metal phosphate. More specifically, it is preferably at least one of cobalt ferrocyanide, iron ferrocyanide, nickel ferrocyanide, manganese ferrocyanide, copper ferrocyanide, zinc ferrocyanide, ammonium phosphotungstate, potassium phosphotungstate, ammonium phosphomolybdate, potassium phosphomolybdate, zirconium phosphate, titanium phosphate, cerium phosphate, tin phosphate, and antimony phosphate.

[0027] The apparatus 1 also includes a third container 4 for accommodating seed crystals M. In the apparatus 1, the term "seed crystals" refers to nuclei (seeds) for the growth of a reactant synthesized by the reaction between the first and second stock solutions. Examples of seed crystals for the apparatus 1 include, but are not limited to, metal powders such as aluminum and titanium, resin powders such as cellulose, glass, ceramics, silica gel, diatomaceous earth, activated carbon, and zeolites. The shape of the seed crystals is not particularly limited, but a spherical shape is a preferred example, as a uniform, regular shape is preferable. The size of the seed crystals M is also not particularly limited, but considering that the average particle size of the adsorbent is preferably 10 μm or more assuming a spherical shape, the average particle size is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 5 μm or more.

[0028] Furthermore, since the seed crystals M are a substance insoluble in liquid, it is preferable that a dispersion liquid for dispersing the seed crystals M is also contained in the third container 4. The dispersion liquid allows the seed crystals M to be introduced into the reaction container 5 described below via piping or the like. The dispersion liquid here is not particularly limited, and may be an aqueous solvent such as water, or an organic solvent such as ether. This can be adjusted appropriately according to the first stock solution and the second stock solution. In other words, hereinafter, the term "seed crystals" may also refer to seed crystals dispersed in a dispersion liquid.

[0029] Furthermore, the size of the adsorbent synthesized by the present apparatus 1 is preferably an average particle size of 10 μm or more. By using a size larger than this, it is possible to match the size and specific gravity to a level that allows it to be used as a filter aid in a spring filter system. If it is smaller than this, it is not suitable as a filter aid in a spring filter system and there is a risk that it will slip through the gaps in the spring filter.

[0030] Furthermore, the present apparatus 1 includes the reaction vessel 5 as described above. Specifically, as described above, the reaction vessel 5 is used to mix the first stock solution L1, the second stock solution L2, and the seed crystals M, and to react the first stock solution L1 and the second stock solution L2 in the presence of the seed crystals M to precipitate a reaction product around the seed crystals M.

[0031] As is clear from the above description, the reaction vessel 5 of the present apparatus 1 is connected to the first vessel 2, the second vessel 3, and the third vessel 4 via pipes 9 such as a first pipe 91, a second pipe 92, and a third pipe 93, respectively, and can receive the first stock solution, the second stock solution, and the seed crystals via these pipes.

[0032] Furthermore, the reaction vessel 5 in the present device 1 has an outer shell 51 and a circulating flow forming member 52 provided inside the outer shell 51, and a circulating flow is formed inside these, causing the adsorbent to grow large.

[0033] The outer shell 51 is a member that serves as the outer shell of the reaction vessel 5. Inside this, a circulation flow is formed as described above, while adsorbents smaller than a predetermined size are once discharged to the outside, circulated, and then taken back inside to be grown again.

[0034] The shape of the outer shell 51 is not limited as long as it has the above-mentioned function, but a preferable example is one having a substantially cylindrical portion with an upper and lower base. By making it cylindrical and installing it so that the bottom is substantially parallel to the vertical direction, it is possible to form a circulating flow using gravity, which has the advantage of making it easy to adjust to this circulating flow.

[0035] Furthermore, the reaction vessel 5 of the present apparatus 1 is provided with a circulating flow forming member 52 inside the outer shell 51. As described above, the circulating flow forming member 52 is not limited as long as it can form a circulating flow inside the outer shell 51, but it is preferable that it has a cylindrical portion 521 with upper and lower through-holes (without an upper or lower bottom). By doing so, for example, an upward flow can be formed inside the cylindrical portion, and a downward flow can be formed outside it and inside the outer shell 51. As a result, a reaction product of the first raw liquid and the second raw liquid can be precipitated around the seed crystal within the circulating flow, and this precipitate can grow.

[0036] It is also preferable that a flange portion 522 is provided at the lower part of the cylindrical portion 521 of the circulating flow forming member 52 of the reaction vessel 5. The provision of this flange portion 522 has the advantage of preventing the formation of an upward flow outside the cylindrical portion 521 and enabling the formation of a stable upward flow. It is also preferable that the upper end portion of the cylindrical portion 521 is formed with a smaller diameter than the middle or bottom portion.

[0037] In addition, it is preferable that at least one of the first stock solution and the second stock solution is supplied to the inside of the cylindrical portion 521 of the circulating flow forming member 52. The cylindrical portion 521 serves as a reaction field for the first stock solution, which has the advantage of enabling efficient adsorbent synthesis. In the example shown in the figure, the first stock solution is provided inside the cylindrical portion 521 of the circulating flow forming member 52 by the first piping 91, but the second piping 92 may also be provided inside.

[0038] The third pipe 93 may be configured to be directly connected to the reaction vessel 5, or may be configured to be connected to at least one of the first pipe 91 and the second pipe 92. The third pipe 93 is used to transport the seed crystals, but the seed crystals themselves will not react even if they come into contact with only the first stock solution or only the second stock solution. Therefore, mixing the seed crystals with the first stock solution or the second stock solution before supplying them has the advantage of enabling more efficient transport and reaction. Note that, in a configuration in which a pipe supplying the solution to the inside of the cylindrical portion 521 of the circulating flow forming member 52 is provided, it is preferable that the third pipe 93 be connected to a pipe other than the pipe supplying the solution to the inside of the cylindrical portion 521.

[0039] The present device 1 also includes a circulating mechanism 6 that removes the unreacted first stock solution L1 and second stock solution L2 from the reaction vessel 5 and returns them to the reaction vessel 5 again.

[0040] Specifically, the circulating mechanism 6 is configured with a pump 61 and a fourth pipe 94 connected to this pump 61, and the fourth pipe 94 is connected to the reaction vessel 5 at two points, with one connection port 941 being an outlet for the reaction liquid and the other connection port 941 being an inlet for returning the reaction liquid via the pump 61.

[0041] Specifically, when the present apparatus 1 is installed, it is preferable that one connection port 941 is installed at the vertical upper part of the reaction vessel 5, and the other connection port 942 is installed at the vertical lower part of the reaction vessel 5. This configuration has the advantage that the reaction liquid can be introduced again into the circulating flow formed by the circulating flow forming member 52 to cause a reaction.

[0042] Furthermore, as described above, the present apparatus 1 preferably includes a collection vessel 7 for collecting the adsorbent synthesized in the reaction vessel 5. The collection vessel 7 enables collection of fully grown adsorbents. The collection vessel 7 preferably includes a sieving mechanism 71. By providing the sieving mechanism 71, adsorbents above a predetermined size are captured by the sieving mechanism 71, while adsorbents below this size are stored in the collection vessel 7, specifically, in the collection vessel main body 72. The adsorbents below the predetermined size stored in the collection vessel main body 72 can be used as seed crystals or nuclei in the next reaction. Therefore, the collection vessel 7 may be provided with a branch pipe 95 connected to the circulation mechanism 6.

[0043] (Method for synthesizing adsorbent) Here, we will explain a method for synthesizing an adsorbent (hereinafter referred to as "this method") using this apparatus 1. This method includes: (S1) a step of reacting a first stock solution and a second stock solution in the presence of seed crystals to precipitate a reaction product around the seed crystals, thereby obtaining a crystallized product (hereinafter also referred to as "crystallization step"); and (S2) a step of classifying the crystallized product to obtain crystallized products of a predetermined size or larger as an adsorbent (hereinafter also referred to as "sorting step").

[0044] First, this method includes a crystallization step (S1), in which the first and second stock solutions are reacted in the presence of seed crystals to precipitate a reaction product around the seed crystals, thereby obtaining a crystallized product.

[0045] In this method, it is also preferable to use the crystallized product of a predetermined size or less as the seed crystal in the crystallization step (S1). This makes it possible to further enlarge the crystallized product of a predetermined size or less. Specifically, in the crystallization step (S1), there may be cases where the seed crystal acts as a nucleus and the crystallized product covers it, but there may also be cases where minute crystallized products are generated in the reaction solution independently of the seed crystal. In such cases, these minute crystallized products themselves can also act as nuclei, and by further enlarging them, it becomes possible to obtain crystallized products larger than the predetermined size.

[0046] This method also includes a sorting step (S2). By sorting, crystallized material of a predetermined size or larger can be obtained as an adsorbent. This sorting step (S2) is assumed to be performed primarily by the collection container 7. Specifically, the adsorbent captured by the sieve mechanism 71 of the collection container 7 is an adsorbent of a predetermined size or larger, while the adsorbent that passes through the sieve mechanism and is stored in the collection container body 72 of the collection container 7 is an adsorbent of a size smaller than the predetermined size.

[0047] As a result of the above, an adsorbent of a predetermined size or larger can be synthesized, coated with reactants deposited around the seed crystal. Figure 2 shows an image of a cross section of an adsorbent synthesized by this apparatus 1.

[0048] As described above, the present invention can provide an adsorbent synthesis method and adsorbent synthesis apparatus that can adjust the size of an adsorbent that can only form fine crystals to be optimal for the filter to be used. [Industrial Applicability]

[0049] INDUSTRIAL APPLICABILITY The present invention has industrial applicability as an adsorbent synthesis method and an adsorbent synthesis apparatus. [Explanation of symbols]

[0050] 1...Adsorbent synthesis equipment 2. First container 3. Second container 4. Third container 5. Reaction vessel 6...Patrol mechanism M...Seed crystal L1: First stock solution L2: Second stock solution

Claims

1. A step of reacting the first stock solution and the second stock solution in the presence of a seed crystal to precipitate a reactant around the seed crystal, thereby obtaining a crystallized product; A method for synthesizing an adsorbent, comprising a step of classifying the crystallized product to obtain crystallized products of a predetermined size or larger as an adsorbent.

2. 2. The method for synthesizing an adsorbent according to claim 1, wherein the adsorbent is at least one of a metal ferrocyanide, a heteropolyacid, and a metal phosphate.

3. the first stock solution is a solution containing at least one of cobalt chloride, ferric chloride, nickel chloride, manganese chloride, copper chloride, zinc chloride, and phosphotungstic acid, phosphomolybdic acid, zirconium chloride oxide, titanium chloride, cerium sulfate, tin chloride, and antimony chloride; 2. The synthesis method according to claim 1, wherein the second stock solution is a solution containing potassium ferrocyanide and at least one of ammonium hydrogen carbonate, ammonium chloride, urea, potassium chloride, phosphoric acid, and sodium dihydrogen phosphate.

4. 2. The method for synthesizing an adsorbent according to claim 1, wherein the adsorbent is at least one of cobalt ferrocyanide, iron ferrocyanide, nickel ferrocyanide, manganese ferrocyanide, copper ferrocyanide, zinc ferrocyanide, ammonium phosphotungstate, potassium phosphotungstate, ammonium phosphomolybdate, potassium phosphomolybdate, zirconium phosphate, titanium phosphate, cerium phosphate, tin phosphate, and antimony phosphate.

5. 2. The method for synthesizing an adsorbent according to claim 1, further comprising the step of contacting the crystallized material having a size equal to or smaller than the predetermined size in the presence of a first stock solution and a second stock solution to precipitate a reaction product around the seed crystal, thereby obtaining a crystallized material having a size equal to or larger than the predetermined size.

6. 2. The method for synthesizing an adsorbent according to claim 1, wherein the predetermined size is an average particle size of 10 μm or more.

7. a first container containing a first concentrate; a second container containing a second concentrate; a third vessel containing seed crystals; a reaction vessel in which the first stock solution, the second stock solution, and the seed crystals are mixed, and the first stock solution and the second stock solution are reacted in the presence of the seed crystals to precipitate a reaction product around the seed crystals; An adsorbent synthesis apparatus comprising a circulating mechanism for removing the unreacted first stock solution and the unreacted second stock solution from the reaction vessel and returning them to the reaction vessel.

8. The reaction vessel comprises:

8. The apparatus for synthesizing an adsorbent according to claim 7, further comprising a circulating flow forming member for forming a circulating flow within the reaction vessel.

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