Resin manufacturing method and ultrapure water manufacturing method

Abstract

To provide a novel production method of catalyst metal carrying resin which is capable of making a purification process efficient, and an ultrapure water production method using catalyst metal carrying resin produced by the method.SOLUTION: A production method of resin X has: filling first anion exchange resin A1 in which catalyst metal is carried and second anion exchange resin A2 in which catalyst metal is not carried into the same container; and purifying the first anion exchange resin A1 and the second anion exchange resin A2 filled into the container together. An ultrapure water production method has: bringing water to be treated containing hydrogen peroxide or dissolved oxygen in contact with ion exchange resin containing at least resin X produced in this manner to reduce the amount of hydrogen peroxide or dissolved oxygen.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a resin, and a method and apparatus for producing ultrapure water using the resin produced thereby. [Background technology]

[0002] It is known that ultraviolet rays are irradiated onto the water to be treated in order to remove organic matter contained in the water. When ultraviolet rays are irradiated onto the water to be treated, water is decomposed and hydroxyl radicals (OH - ), and the hydroxyl radicals react with the organic matter, decomposing the organic matter. Hydroxy radicals react with each other without reacting with organic matter to produce hydrogen peroxide. If ultrapure water containing hydrogen peroxide is supplied to a point-of-use (e.g., a cleaning device for electronic components such as wafers), it may cause damage to the wafers, so it is desirable to remove as much excess hydrogen peroxide as possible. One known method for achieving this is to contact the water to be treated with an anion exchange resin carrying a catalytic metal such as palladium (hereinafter referred to as catalytic metal-supported resin) (Patent Document 1). This method promotes the decomposition reaction of hydrogen peroxide (2H2O2 → 2H2O + O2) through the catalytic action of the catalytic metal, allowing for efficient removal of hydrogen peroxide. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 60-71085 Summary of the Invention [Problem to be solved by the invention]

[0004] In water treatment systems such as ultrapure water production systems, anion exchange resins that do not support catalytic metals (hereinafter referred to as catalytic metal-unsupported resins) are also used. Traditionally, catalytic metal-supported resins and catalytic metal-unsupported resins are separate products and have been refined separately. Therefore, when both catalytic metal-supported resins and catalytic metal-unsupported resins are required, it is difficult to reduce costs and shorten the time required for production.

[0005] An object of the present invention is to provide a new method for producing a resin that can improve the efficiency of the purification process, and a method for producing ultrapure water using the resin produced thereby. [Means for solving the problem]

[0006] The resin manufacturing method of the present invention is a method for manufacturing a resin by placing a first anion exchange resin carrying a catalytic metal and a second anion exchange resin not carrying a catalytic metal in the same container. The same space and filling the container with the The same space as above and co-purifying the first anion exchange resin and the second anion exchange resin packed in a tubular container.

[0007] The method for producing ultrapure water of the present invention comprises contacting water to be treated containing hydrogen peroxide or dissolved oxygen with a resin produced by the above-described method for producing a resin, thereby reducing the amount of hydrogen peroxide or dissolved oxygen. [Effects of the Invention]

[0008] In the present invention, the first anion exchange resin and the second anion exchange resin packed in a container are purified together. Therefore, the present invention provides a new method for producing a resin that can improve the efficiency of the purification process, and a method for producing ultrapure water using the resin produced thereby. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a subsystem of an ultrapure water production apparatus according to an embodiment of the present invention. [Figure 2]FIG. 1 is a conceptual diagram showing a purification method and a packing method for a catalytic metal-supported resin and a cation exchange resin. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an overview of subsystem 1 of an ultrapure water production apparatus according to one embodiment of the present invention. Subsystem 1, also referred to as a secondary pure water system, produces ultrapure water from pure water produced in a primary pure water system to be supplied to a point of use 20. Subsystem 1 includes a primary pure water tank 2, a pure water supply pump 3, a heat exchanger 4, an ultraviolet oxidation device 5, an ion exchange device 6, a degassing device 7, and an ultrafiltration membrane device 8, which are arranged in series in this order along a main pipe L1 in the direction D of flow of the water to be treated. The branching portion of main pipe L1 to point of use 20 is connected to the primary pure water tank 2 by a return line L2, which returns ultrapure water not used at point of use 20 to the primary pure water tank 2. The primary pure water tank 2 stores pure water produced in the primary pure water system. This pure water, i.e., the water to be treated in subsystem 1, may contain dissolved oxygen. According to the method for producing ultrapure water of this embodiment, the amount of hydrogen peroxide or dissolved oxygen is reduced by contacting the water to be treated, which contains hydrogen peroxide or dissolved oxygen, with an ion exchange resin containing at least a catalytic metal-supported resin. The catalytic metal-supported resin is produced by the production method described below.

[0011] The water to be treated stored in the primary pure water tank 2 is pumped by a pure water supply pump 3, and after temperature adjustment in a heat exchanger 4, is supplied to an ultraviolet oxidation device 5. The ultraviolet oxidation device 5 irradiates the water to be treated with ultraviolet light to decompose organic matter contained in the water. For example, an ultraviolet lamp with at least one of wavelengths of 254 nm, 185 nm, and 172 nm can be used as the ultraviolet irradiation device 5. When the water to be treated is irradiated with ultraviolet light, the water is decomposed to produce hydroxyl radicals (OH -) is generated, and the hydroxyl radicals react with the organic matter, decomposing the organic matter. If the hydroxyl radicals do not react with the organic matter but react with each other, hydrogen peroxide is produced. In other words, the water to be treated that is supplied to the ion exchange device 6 is treated water obtained by irradiating water containing organic matter with ultraviolet light to oxidatively decompose the organic matter, and this treated water contains hydrogen peroxide produced by the ultraviolet irradiation. The ion exchange device 6 will be described later.

[0012] The degassing device 7 removes dissolved oxygen and carbon dioxide from the water to be treated. Degassing is performed, for example, by membrane degassing. In membrane degassing, the water to be treated is passed through one side of a degassing membrane, and the pressure on the other side is reduced by a vacuum pump. This allows the dissolved oxygen and carbon dioxide in the water to pass through the degassing membrane and be removed from the water to be treated. The ultrafiltration membrane device 8 is provided to remove fine particles. Examples of the ultrafiltration membrane device 8 include those using membranes with a molecular weight cutoff of 4000 or more (for example, approximately 4000 to 6000). Ultrafiltration membranes that have little elution from the membrane itself are preferred, and polysulfone is a suitable material. The ultrapure water treated by the ultrafiltration membrane device 8 is supplied to a point of use 20.

[0013] Although not shown in the figure, if the water to be treated contains dissolved oxygen, hydrogen may be added to the water to be treated. The oxygen reacts with hydrogen in the presence of a catalytic metal to form water, thereby removing the dissolved oxygen. Since hydrogen can be added before the water to be treated is treated with a catalytic metal-supported resin, the hydrogen addition equipment is installed upstream of the ion exchange device 6.

[0014] The ion exchange device 6 is filled with a catalytic metal-supported resin X and a cation exchange resin K2 (see FIG. 2). The catalytic metal-supported resin X consists of a first catalytic metal-supported resin R1' and a second catalytic metal-supported resin R2'. In the following description, the first catalytic metal-supported resin R1' (Example) and the second catalytic metal-supported resin R2' (Example), as well as the catalytic metal-supported resin R1 (Comparative Example) and the catalytic metal-unsupported resin R2 (Comparative Example), are individual resin particles. The first catalytic metal-supported resin R1' is an anion exchange resin carrying a catalytic metal capable of decomposing hydrogen peroxide. The first catalytic metal-supported resin R1' decomposes hydrogen peroxide generated by ultraviolet irradiation and removes anion components. Examples of catalytic metals include platinum group metals such as palladium (Pd) and platinum (Pt). The second catalytic metal-supported resin R2' preferably has a base resin substantially identical to or identical to the first catalytic metal-supported resin R1'. The second catalytic metal-supported resin R2' may contain resin particles carrying a catalytic metal capable of decomposing hydrogen peroxide and resin particles not carrying a catalytic metal capable of decomposing hydrogen peroxide. However, the proportion of resin particles not carrying a catalytic metal is typically higher than that of the first catalytic metal-supported resin R1'. Like the first catalytic metal-supported resin R1', the second catalytic metal-supported resin R2' decomposes hydrogen peroxide generated by the ultraviolet irradiation device 5 and removes anionic components. The cation exchange resin K2 removes cationic components. The cation exchange resin K2 does not carry a catalytic metal capable of decomposing hydrogen peroxide. The flow rate of the ion exchange device 6 is preferably set so that the water to be treated contacts the catalytic metal-supported resin X at a space velocity of 30 ( / hr) or more and 2000 ( / hr) or less. This allows hydrogen peroxide to be efficiently removed while maintaining a sufficient treatment flow rate. The concentration of hydrogen peroxide in the treated water treated with catalytic metal-supported resin X is reduced to 5 μg / L (ppb) or less.

[0015] Here, we will explain the manufacturing and packing methods for the first catalytic metal-supported resin R1', the second catalytic metal-supported resin R2', and the cation exchange resin K2. The first catalytic metal-supported resin R1' is produced by purifying the first anion exchange resin A1, which is supported with a catalytic metal capable of decomposing hydrogen peroxide. The second catalytic metal-supported resin R2' is produced by purifying the second anion exchange resin A2. In the purification process, an acidic solution is passed through the resin, followed by an alkaline solution. The concentrations, flow rates, and flow times of the acidic and alkaline solutions can be appropriately set as long as the amount of impurities, such as organic matter, eluted from the first and second anion exchange resins A1 and A2 is below a set value (target value) and the ratio of OH-type to the total exchange capacity of the first anion exchange resin A1 and the second anion exchange resin A2 combined is above a set value (target value). Examples of the acidic solution that can be used include HCl and HNO3. Examples of alkaline solutions that can be used include NaOH and TMAH (tetramethylammonium hydroxide). The first anion exchange resin A1 and the second anion exchange resin A2 preferably have substantially the same matrix resin. Substantially the same matrix resin means that the matrix resins are made from the same raw materials and have the same basic physical properties. This facilitates homogeneous mixing of the first anion exchange resin A1 and the second anion exchange resin A2, ensuring uniform quality. It is particularly preferred that the matrix resins of the first anion exchange resin A1 and the second anion exchange resin A2 be of the same brand.

[0016] The first and second anion exchange resins A1 and A2 may be porous or MR-type, but a gel-type resin is preferred because it minimizes the elution of organic matter. At least one of the first anion exchange resin A1 and the second anion exchange resin A2 may be in the Cl-type before purification (i.e., when packed into the purification vessel). This is because anion exchange resins are generally distributed in the Cl-type. Both the first anion exchange resin A1 and the second anion exchange resin A2 may be in the Cl-type before purification. This allows the first anion exchange resin A1 and the second anion exchange resin A2 to be purified in the same process, further streamlining the overall process. Alternatively, both the first anion exchange resin A1 and the second anion exchange resin A2 may be in the OH-type before purification.

[0017] In this embodiment, 70% or more, preferably 90% or more, and more preferably 95% or more of the total exchange capacity of all anion exchange resins, including the first anion exchange resin A1 and the second anion exchange resin A2, is converted to the OH form after purification. The OH form of the first catalytic metal-supported resin R1' and the second catalytic metal-supported resin R2' is easily contacted with HO, improving the HO decomposition and removal performance. The amount of catalytic metal supported on the first anion exchange resin A1 is preferably 10 mg catalyst / LR (R is the anion exchange resin in the OH form, meaning the weight of catalyst per 1 L of anion exchange resin) or more and 500 mg catalyst / LR or less.

[0018] Figure 2(a) is a conceptual diagram showing the purification method and packing method for catalytic metal-supported resin R1, catalytic metal-unsupported resin R2, and cation exchange resin K2 in Comparative Example 1 (conventional example), and Figure 2(b) is a conceptual diagram showing the purification method and packing method for first catalytic metal-supported resin R1', second catalytic metal-supported resin R2', and cation exchange resin K2 in Example 1.

[0019] In Comparative Example 1, catalytic metal-supported resin R1, catalytic metal-free resin R2, and cation exchange resin K2 are produced separately. That is, a first anion exchange resin A1 supported with a catalytic metal capable of decomposing hydrogen peroxide, a second anion exchange resin A2 not supported with a catalytic metal capable of decomposing hydrogen peroxide, and cation exchange resin K1 are separately supplied to a purification vessel and purified at the plant. The first anion exchange resin A1 is in the Cl form and is converted to the OH form by purification to become catalytic metal-supported resin R1. The second anion exchange resin A2 is in the Cl form and is converted to the OH form by purification to become catalytic metal-free resin R2. The cation exchange resin K1 is in the Na form and is converted to the H form by purification to become cation exchange resin K2. Thus, purification is a process that involves changing the ionic form of the ion exchange groups of the resins.

[0020] Next, a mixing process is carried out. In the mixing process, catalytic metal-unsupported resin R2 and cation exchange resin K2 are mixed. Catalytic metal-supported resin R1 is not mixed and is shipped as a product. At the site, the mixed resin of catalytic metal-unsupported resin R2 and cation exchange resin K2 is filled into ion exchange device 6. Next, catalytic metal-supported resin R1 is filled into ion exchange device 6. As a result, the mixed resin of catalytic metal-unsupported resin R2 and cation exchange resin K2 is filled into the bottom of ion exchange device 6, and catalytic metal-supported resin R1 is filled on top of that.

[0021] In contrast, in Example 1, a first anion exchange resin A1 loaded with a catalytic metal and a second anion exchange resin A2 not loaded with a catalytic metal are first packed into the same purification vessel at a factory. The first anion exchange resin A1 and the second anion exchange resin A2 may be mixed, but it is preferable to stack the first anion exchange resin A1 on top of the second anion exchange resin A2. This is because the catalytic metal detached from the first anion exchange resin A1 falls by gravity and is more likely to reattach to the second anion exchange resin A2. When the first anion exchange resin A1 and the second anion exchange resin A2 are mixed, they may be mixed at any time before the start of purification, either before or after filling the purification vessel.

[0022] In the purification process, these stacked or mixed resins are converted from the Cl form to the OH form, producing a new catalytic metal-supported resin X. That is, the first anion exchange resin A1 and the second anion exchange resin A2 packed in a purification vessel are purified together to produce a catalytic metal-supported resin X consisting of a first catalytic metal-supported resin R1' and a second catalytic metal-supported resin R2'. Specifically, the first anion exchange resin A1 carrying the catalytic metal is purified to become the first catalytic metal-supported resin R1', with a portion of the metal catalyst being released from the resin constituting the first catalytic metal-supported resin R1'. The second anion exchange resin A2 is also purified to become the second catalytic metal-supported resin R2', with the metal catalyst released from the first anion exchange resin A1 being reloaded onto the resin constituting the second catalytic metal-supported resin R2'. Thus, the catalytic metal-supported resin X of Example 1 is a novel catalytic metal-supported resin that differs from the mixture of catalytic metal-supported resin R1 and catalytic metal-unsupported resin R2 of Comparative Example 1. The cation exchange resin K1 is converted from the Na form to the H form by purification to become the cation exchange resin K2, and this process is the same as that of Comparative Example 1. Next, in the mixing process, the novel catalytic metal-supported resin X and the cation exchange resin K2 are mixed to prepare a novel mixed resin Y, and the mixed resin Y is filled into the ion exchange device 6 on-site.

[0023] Table 1 shows a comparison between Example 1 and Comparative Example 1 regarding the purification of anion exchange resins. The water consumption is the amount of pure water used for cleaning, etc., the chemical consumption is the amount of chemicals used in the purification, the time required is the total time required for the purification, and the cost is the total cost required for the purification. All figures are normalized to Comparative Example 1 as 1. In Comparative Example 1, purification was performed twice, with the first anion exchange resin A1 and the second anion exchange resin A2 separately. Because there is less demand for the catalyst metal-supported resin R1 than for the catalyst metal-unsupported resin R2, the purification volume of the first anion exchange resin A1 was less than that of the second anion exchange resin A2. Therefore, the purification volume of the first anion exchange resin A1 was set to 1 / 6 of the purification volume of the second anion exchange resin A2. In Example 1, only one purification was performed on the mixed resin of the first anion exchange resin A1 and the second anion exchange resin A2. The total purification amount of the first anion exchange resin A1 and the second anion exchange resin A2 was the same as the purification amount of the second anion exchange resin A2 in Comparative Example 1. Example 1 showed better results than Comparative Example 1 in all indexes.

[0024] [Table 1]

[0025] Furthermore, refining catalytic metal-supported resin R1 and catalytic metal-unsupported resin R2 using the same equipment presents the following challenges. Industrially, using large-scale facilities to purify resins is advantageous in terms of efficiency, quality, and cost. However, as mentioned above, because demand for catalytic metal-supported resin R1 is limited, the amount of catalytic metal-supported resin R1 produced in one purification run is less than the rated capacity of the purification equipment. This reduces the bed height of the first anion exchange resin A1, resulting in variations in the amount of water passing through it. This could lead to poor purification, such as insufficient supply of chemicals or wash water to some parts of the resin bed. While reducing the amount of chemicals and wash water (or the space velocity SV and linear velocity LV) could address this issue, this would mean using the purification equipment in a manner different from its intended use, making quality control in the purification process more difficult. Producing catalytic metal-supported resin R1 in an amount equivalent to the rated capacity of the purification equipment would solve this problem, but it could result in increased inventory of catalytic metal-supported resin R1. It is possible to install a refining facility of an optimum size in accordance with the required amount (market size) of catalyst metal-supported resin R1, but this would result in increased costs due to capital investment.

[0026] In contrast, in Example 1, an anion exchange resin containing a first anion exchange resin A1 and a second anion exchange resin A2 in a desired ratio is purified. As described above, the purification process for the first anion exchange resin A1 and the second anion exchange resin A2 is the same, so the same purification process can be applied to a resin in which the first anion exchange resin A1 and the second anion exchange resin A2 are layered or mixed. Since this resin is produced in an amount equivalent to the rated capacity of the purification equipment, quality control and inventory issues are also eliminated.

[0027] In the comparative example, the catalyst metal-unsupported resin R2 and the cation exchange resin K2 are mixed and then filled, followed by the catalyst metal-supported resin R1. However, the additional mixing and filling process may impair the purity of the resin. To solve this problem, it is desirable to simplify each process as much as possible. In this embodiment, the filling process only needs to be done once, reducing the possibility of resin contamination.

[0028] Furthermore, in the comparative example, during the purification step, a portion of the metal catalyst is desorbed from the first anion exchange resin A1 and discharged outside the system, but platinum group metal catalysts are expensive, which significantly impacts costs. In contrast, in Example 1, as described above, a portion of the metal catalyst desorbed from the first anion exchange resin A1 is reloaded onto the second anion exchange resin A2, which does not support a metal catalyst, allowing for effective use of the expensive metal catalyst.

[0029] Next, using a test apparatus equivalent to that shown in Figure 1, the characteristics of the catalytic metal-supported resin R1 and catalytic metal-supported resin X prepared by the above-mentioned method were confirmed. A first anion exchange resin A1, in which a metal catalyst was supported on a Cl-form anion exchange resin, and a second anion exchange resin A2, which was identical to the metal catalyst-supported resin A except that it did not support a metal catalyst, were prepared. In Example 2, the first anion exchange resin A1 and the second anion exchange resin A2 were packed into the same column (corresponding to the above-mentioned purification vessel) and purified. In Comparative Example 2, only the first anion exchange resin A1 was packed into the column and purified. In Table 2, R-OH is an index indicating the proportion of OH-form, i.e., the extent to which purification was performed. The catalyst loading is the weight of the metal catalyst supported by all the anion exchange resins in the column after purification. The HO removal performance indicates the HO concentrations at the column inlet and outlet when HO-containing water to be treated is passed through the column. The purification efficiency (R-OH) was superior in Example 2, confirming that Example 2 had improved quality. The catalyst loading amount was also superior in Example 2. This is thought to be because a portion of the metal catalyst detached from the first anion exchange resin A1 was reloaded onto the second anion exchange resin A2. The H2O2 removal performance was equivalent in Example 2 and Comparative Example 2.

[0030] [Table 2] [Explanation of symbols]

[0031] 1 Subsystem 2 Primary pure water tank 3 Pure water supply pump 4 Heat exchanger 5. UV oxidation equipment 6. Ion exchange unit 7. Membrane degassing device 8. Ultrafiltration Membrane Device 20 Use Points A1 First anion exchange resin (Cl form) A2 Second anion exchange resin (Cl form) K1 Cation Exchange Resin (Na Form) K2 Cation Exchange Resin (H Type) R1 Catalyst metal-supported resin (OH type) (comparison example) R1' First catalytic metal-supported resin (OH type) (Example) R2 Non-catalytic metal-supported resin (OH type) (comparison example) R2' Second catalytic metal-supported resin (OH type) (Example) X Catalyst metal-supported resin

Claims

1. Filling a first anion exchange resin carrying a catalytic metal and a second anion exchange resin not carrying a catalytic metal into the same space of the same container; Purifying the first anion exchange resin and the second anion exchange resin packed in the same space of the container together; A method for producing a resin having the formula:

2. 2. The method of claim 1, wherein the first anion exchange resin is layered on top of the second anion exchange resin.

3. The method for producing a resin according to claim 1 or 2, wherein at least one of the first anion exchange resin and the second anion exchange resin is in the Cl form before purification.

4. The method for producing a resin according to claim 1 , wherein the first anion exchange resin and the second anion exchange resin have substantially the same base resin.

5. 5. The method for producing a resin according to claim 1, wherein the catalytic metal is a platinum group metal having hydrogen peroxide decomposition ability, and the amount of the catalytic metal supported on the first anion exchange resin is 10 mg-catalyst / L-R or more and 500 mg-catalyst / L-R or less.

6. 6. The method for producing a resin according to claim 1, wherein during purification, a portion of the catalytic metal is desorbed from the first anion exchange resin, and the desorbed catalytic metal is reloaded onto the second anion exchange resin.

7. A method for producing ultrapure water, comprising contacting water to be treated containing hydrogen peroxide or dissolved oxygen with an ion exchange resin containing at least a catalytic metal-supported resin produced by the resin production method described in any one of claims 1 to 6, thereby reducing the amount of the hydrogen peroxide or dissolved oxygen.

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