Water treatment device and water treatment method

Abstract

The invention provides a water treatment device and a water treatment method which can stably remove oxidizing substances such as oxygen and hydrogen peroxide in a catalyst device and can stably obtain good treated water quality. A water treatment device (1) is provided with: a hydrogen addition device (10) for adding hydrogen to water to be treated containing at least hydrogen peroxide; and an oxidizing substance removal device (11) into which the water to be treated to which hydrogen has been added by the hydrogen addition device (10) flows, the oxidizing substance removal device (11) being provided with: a catalyst device (20) which is provided with a catalyst metal-supporting resin and in which the catalyst metal-supporting resin is supported; a catalyst metal-supporting resin that removes the hydrogen peroxide from the water to be treated by bringing into contact with the water to be treated to which hydrogen has been added by the hydrogen addition device (10); a concentration measurement means (21) for measuring the dissolved hydrogen concentration of the water to be treated that has been treated by the catalyst device (20); and a control means (22) for controlling the hydrogen addition amount of the hydrogen addition device (10) on the basis of the dissolved hydrogen concentration measured by the concentration measurement means (21), the catalyst metal-supporting resin being a catalyst metal-supporting resin in which a platinum group metal-supporting catalyst is supported on a carbonic acid-type anion exchange resin.

Description

TECHNICAL FIELD

[0001] The present application relates to a water treatment apparatus and a water treatment method. BACKGROUND

[0002] For example, as water for cleaning electronic components such as silicon wafers in a semiconductor manufacturing process, ultrapure water in which impurities are highly removed is used. In the case where ultrapure water is used as water for cleaning electronic components, if oxidizing substances such as oxygen and hydrogen peroxide are dissolved in the ultrapure water, it becomes a main cause of forming a natural oxide film on the surface of the electronic components.

[0003] In an ultrapure water manufacturing system, for example, in a primary water manufacturing apparatus, a secondary water manufacturing apparatus (subsystem), a degassing device (membrane type degassing device, catalyst degassing device, etc.) is provided, and the concentration of oxidizing substances is reduced.

[0004] In the case where a membrane type degassing device is used as a degassing device, in a primary water manufacturing apparatus, a plurality of degassing devices are provided in series, and the treatment of oxidizing substances is performed.

[0005] As a method of removing oxidizing substances such as oxygen and hydrogen peroxide dissolved in ultrapure water, a method of removing oxidizing substances using a platinum group metal supported catalyst obtained by supporting a platinum group metal typified by palladium (Pd) and platinum (Pt) on a carrier has been proposed (for example, Patent Document 1). By using a platinum group metal supported catalyst, not only hydrogen peroxide can be decomposed and removed by a reaction represented by 2H2O2→2H2O+O2, but also oxygen contained in the treated water can be removed by reacting with hydrogen (H2) in the presence of hydrogen (H2) (2H2+O2→2H2O). Although oxygen is generated when hydrogen peroxide is decomposed by a platinum group metal supported catalyst, the oxygen can be removed by reacting with hydrogen in the presence of a platinum group metal supported catalyst. In the case where a platinum group metal supported catalyst is used to remove oxygen and hydrogen peroxide from treated water, hydrogen needs to be contained in the treated water, and hydrogen is added to the treated water as necessary.

[0006] PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: Japanese Patent Application Publication No. 2016-215150 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION Generally, as a carrier (ion exchanger) of a platinum group metal supported catalyst, an OH type carrier is used. However, as a result of intensive studies repeatedly made by the present inventors and others, it has been found that if carbonic acid is present in the treated water of the catalyst device, the carrier (ion exchanger) changes to a carbonic acid type due to a change over time, and the removal performance of oxidizing substances such as oxygen and hydrogen peroxide decreases, and thus the present application has been completed.

[0007] The present application has an object to provide a water treatment device and a water treatment method capable of inhibiting a decrease in the removal performance of oxidizing substances such as oxygen and hydrogen peroxide in a catalyst device, and stably obtaining a good treated water quality.

[0008] Technical solution for solving the problem To achieve the above object, the water treatment device of the present application has: a hydrogen adding device that adds hydrogen to treated water containing at least hydrogen peroxide; and an oxidizing substance removal device that flows the treated water to which hydrogen has been added by the hydrogen adding device, the oxidizing substance removal device has: a catalyst device that has a catalyst metal-supporting resin that removes the hydrogen peroxide from the treated water by contacting the treated water to which hydrogen has been added by the hydrogen adding device; a concentration measuring unit that measures the dissolved hydrogen concentration of the treated water after being treated by the catalyst device; and a control unit that controls the hydrogen addition amount of the hydrogen adding device based on the dissolved hydrogen concentration measured by the concentration measuring unit, the catalyst metal-supporting resin is a catalyst metal-supporting resin supported on a carbonate-type anion exchange resin.

[0009] In addition, the water treatment method of the present application has an oxidizing substance removal process that removes oxidizing substances from treated water, in which: the oxidizing substance removal process has: a process of adding hydrogen to the treated water; and a process of passing the treated water to which hydrogen has been added to a catalyst device that has a catalyst metal-supporting resin, in the process of adding hydrogen to the treated water, the amount of hydrogen added to the treated water is controlled so that the dissolved hydrogen concentration in the treated water at the outlet of the catalyst device becomes a set value, the catalyst metal-supporting resin is a catalyst metal-supporting resin in which a platinum group metal catalyst is supported on a carbonate-type anion exchange resin.

[0010] Effects of the Invention According to the present application, it is possible to provide a water treatment device and a water treatment method capable of inhibiting a decrease in the removal performance of oxidizing substances such as oxygen and hydrogen peroxide in a catalyst device, and stably obtaining a good treated water quality. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1is a schematic configuration view showing an embodiment of the water treatment device of the present application.

[0012] Figure 2 is a schematic configuration view showing an embodiment of the oxidizing substance removal device used in the present application.

[0013] Figure 3 is a schematic configuration view showing an embodiment of the catalyst device used in the present application.

[0014] Figure 4 is a flowchart of the system used in the examples and comparative examples.

[0015] Figure 5 is a graph obtained by evaluating the correlation between the proportion of OH form in a carbonate-type anion exchange resin and the H2O2 removal performance.

[0016] Figure 6 is a graph obtained by comparatively evaluating the water quality of the treated water in the case where the DH concentration at the column outlet is controlled to a set value and in the case where the DO concentration at the column outlet is controlled to a set value.

[0017] Figure 7 is a graph obtained by comparatively evaluating the water quality of the treated water in the case where the layer height of the catalyst metal-supporting resin filled in the column is set to 30 cm and in the case where the layer height is set to 50 cm.

[0018] Figure 8 is a graph obtained by comparatively evaluating the water quality of the treated water in the case where the water passing speed LV of the treated water to the catalyst device is changed. DETAILED DESCRIPTION

[0019] Hereinafter, an embodiment of the present application will be described with reference to the drawings.

[0020] Figure 1 is a schematic configuration view showing an embodiment of the water treatment device of the present application.

[0021] As shown in Figure 1 , the water treatment device 1 according to the present embodiment is provided with a pretreatment device 2, a primary pure water manufacturing device 26, and a subsystem 27.

[0022] The pretreatment system 2 performs pretreatment of raw water. The pretreatment system 2 is provided with, for example, a turbidity removal membrane device.

[0023] The primary pure water production device 26 includes a primary pure water tank 3, a cation exchange column (K column) 4, a decarbonation column (D column) 5, an anion exchange column (A column) 6, a reverse osmosis (RO) membrane device 7, a secondary pure water tank 8, an ultraviolet oxidation device 9, a hydrogen addition device 10, and an oxidizing substance removal device 11. These devices 3 to 11 are arranged in the order of upstream to downstream along the water flow direction of the treated water.

[0024] The subsystem 27 includes a sub-tank 12, a pump 13, a heat exchanger 14, an ultraviolet oxidation device 15, a catalytic reaction device 16, a monoblock pure water device (non-regeneration type mixed bed ion exchange resin device) 17, and an ultrafiltration membrane device 18. These devices 12 to 18 are arranged in the order of upstream to downstream along the water flow direction of the treated water.

[0025] The water treatment device 1 produces ultrapure water by sequentially treating raw water by the pretreatment system 2, the primary pure water production device 26, and the subsystem 27, and supplies the ultrapure water to the use point 19.

[0026] The raw water is pretreated by the pretreatment device 2, and filtered water is produced from the raw water.

[0027] The filtered water from the pretreatment device 2 is supplied to the primary pure water tank 3, and a part is stored. The filtered water is removed of cation components in the K column 4, removed of carbonic acid components in the D column 5, removed of anion components in the A column 6, and removed of ionic impurities, non-ionic organic substances, and the like in the reverse osmosis membrane device (RO) 7. Then, the treated water subjected to these treatments is supplied to the secondary pure water tank 8, and a part is stored.

[0028] Then, the treated water is supplied from the secondary pure water tank 8 to the ultraviolet oxidation device 9. In the ultraviolet oxidation device 9, the treated water is irradiated with ultraviolet rays, and the organic substances in the treated water are decomposed. When the treated water is irradiated with ultraviolet rays, hydrogen peroxide is generated. The treated water containing the hydrogen peroxide after the ultraviolet irradiation and further containing dissolved oxygen is supplied to the oxidizing substance removal device 11 after hydrogen is added by the hydrogen addition device 10. In the oxidizing substance removal device 11, most of the oxidizing substances contained in the treated water are removed. The "oxidizing substances" referred to here include hydrogen peroxide generated by the ultraviolet irradiation, dissolved oxygen originally contained in the treated water, and oxygen generated by the decomposition of hydrogen peroxide in the oxidizing substance removal device 11. The treated water from which most of the oxidizing substances are removed is supplied to the subsystem 27.

[0029] In the subsystem 27, the treated water stored in the sub-tank 12 is sent out by the pump 13 and supplied to the heat exchanger 14. The treated water temperature-adjusted by the heat exchanger 14 is supplied to the ultraviolet oxidation device 15 and irradiated with ultraviolet rays, and the remaining organic substances in the treated water are further decomposed. Then, the treated water is processed in the order of the catalytic reaction device 16, the cartridge polisher 17, and the ultrafiltration membrane device 18. In the catalytic reaction device 16, the hydrogen peroxide newly generated by the ultraviolet oxidation device 15 is removed, and further, oxygen generated due to the decomposition of the hydrogen peroxide is removed in a membrane degassing device (not shown) provided appropriately, and in the monoblock-type pure water device 16, metals and the like are removed by ion exchange processing. Then, the treated water is removed of fine impurities in the ultrafiltration membrane device 18.

[0030] A part of the thus-obtained ultrapure water is supplied to the use point 19, and the remaining part is returned to the sub-tank 12.

[0031] Note that, in the ultrapure water manufacturing system, there are cases where a plurality of degassing devices (membrane-type degassing devices) are provided in series in the primary pure water manufacturing device to reduce the concentration of oxidizing substances (particularly, the concentration of dissolved oxygen) of the treated water and supply the treated water to the subsystem 27. However, if a plurality of membrane-type degassing devices are provided in series, the space required on the ultrapure water manufacturing system becomes larger. In addition, the membrane-type degassing devices can have failures such as water leakage and component breakage. Furthermore, the life is about 5 to 10 years, and replacement is required each time, so cost is also consumed. In the invention related to the present embodiment, in the primary pure water manufacturing device 26, instead of the conventional structure in which a plurality of membrane-type degassing devices are provided in series, the degassing device that adds hydrogen to the treated water and utilizes catalytic reaction, that is, the hydrogen adding device 10 and the oxidizing substance removing device 11 are used, and thus, ultrapure water can be manufactured with less space and at low cost.

[0032] In the water processing device 1, as to the structures other than the structure in which the process of removing oxidizing substances from the treated water, that is, the process of adding hydrogen to the treated water, and the process of passing the treated water to which hydrogen has been added to the catalyst device provided with a catalyst metal-supported resin are performed, the structures generally used in water processing devices can be used. Therefore, the detailed structures are omitted from the description, and the hydrogen adding device 10 and the oxidizing substance removing device 11 are described below.

[0033] The hydrogen adding device 10 adds hydrogen to the treated water. The treated water contains dissolved oxygen in addition to hydrogen peroxide generated by ultraviolet irradiation.

[0034] As for the hydrogen addition device 10, any device capable of adding hydrogen to the water being treated can be used. For example, a hydrogen addition device utilizing a gas dissolution method using a gas dissolution membrane or a hydrogen addition device utilizing a direct electrolysis method using an electrolysis unit can be used. In this embodiment, a hydrogen addition device capable of adding hydrogen to the water being treated with good responsiveness and accuracy is preferred. Therefore, a direct electrolysis method, in which the amount of hydrogen added can be rapidly adjusted by changing the voltage applied between the electrodes, is preferred.

[0035] Figure 2 This is a schematic structural diagram showing one embodiment of the oxidizing substance removal device 11. Figure 3 This is a schematic structural diagram illustrating one embodiment of the catalyst device.

[0036] like Figure 2 As shown, the oxidizing substance removal device 11 includes a catalyst device (catalyst tower) 20, a concentration measuring unit 21, and a control unit 22.

[0037] like Figure 3 As shown, the catalyst unit 20 is filled with catalyst metal-supported resin 23 inside the unit (tower). A coarse filter 25 is provided on the bottom surface of the catalyst unit 20.

[0038] The catalyst metal supported resin 23 is formed by supporting a catalyst metal on a support. Platinum group metals are used as the catalyst metal. Platinum group metals are a collective term for ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), and platinum (Pt). In this invention, palladium or platinum is preferred, and palladium is particularly preferred considering catalytic activity. An anion exchange resin is used as the support from the viewpoint of catalyst adjustment and reactivity. In this embodiment, a carbonate-type anion exchange resin (a resin of carbonate type) is used as the anion exchange resin. If the water being treated in the oxidizing agent removal device 11 contains carbonic acid, for example, an OH-type anion exchange resin may change from OH-type to carbonate-type over time, thus potentially reducing the removal performance of oxidizing agents such as oxygen and hydrogen peroxide. Furthermore, resin replacement due to deterioration cannot be avoided. In this embodiment, by using a carbonate-type anion exchange resin, it is not affected by the time-related changes caused by carbonic acid, can maintain stable performance, and can be used semi-permanently. It should be noted that, based on the results of the embodiments described later, in this invention, an anion exchange resin in which the OH form accounts for 60% or less of the resin type of the anion exchange resin (in other words, the carbonate form accounts for 40% or more of the resin type of the anion exchange resin) is defined as a carbonate-type anion exchange resin.

[0039] The catalyst loading is preferably 10 mg-catalyst / LR or higher and 500 mg-catalyst / LR or lower. If it is 10 mg-catalyst / LR or higher, peroxides can be effectively removed. If it exceeds 500 mg-catalyst / LR, there may be issues such as increased costs.

[0040] There are no particular restrictions on the size or shape of the catalyst support; granular or particulate forms are both acceptable.

[0041] The catalyst metal-supported resin 23 has the function of decomposing hydrogen peroxide into water and oxygen by contacting the treated water containing hydrogen peroxide (2H2O2→2H2O+O2). Simultaneously, the catalyst metal-supported resin 23 also has the function of reacting hydrogen added to the treated water via the hydrogen addition device 10, i.e., dissolved hydrogen in the treated water (dissolved hydrogen), with dissolved oxygen in the treated water (dissolved oxygen) to generate water (2H2+O2→2H2O). At this time, the dissolved oxygen removed by the catalyst metal-supported resin 23 originates from dissolved oxygen originally dissolved in the treated water supplied to the oxidizing agent removal device 11, and from dissolved oxygen generated through the aforementioned decomposition. Thus, the catalyst device 20 can remove oxidizing substances from the treated water by contacting the hydrogen-containing treated water with the catalyst metal-supported resin 23. The treated water, after the oxidizing substances have been removed by the catalytic reaction device 12, flows into the subsystem 27.

[0042] Next, the filling method of the catalyst metal-supported resin 23 in the catalyst device 20 will be explained.

[0043] As previously described, a coarse filter 25 is provided within the catalyst unit 20. The coarse filter 25 acts as a filter, preventing leakage of the resin packed within the unit (tower) to the downstream section (outside the unit) and allowing treated water to pass through. In this embodiment, the coarse filter 25 is positioned on the bottom surface of the catalyst unit 20 such that it covers the outlet of the treated water in the bottom surface of the catalyst unit 20, protruding upwards from the bottom surface of the catalyst unit 20. In this embodiment, packing material 24 is filled around the coarse filter 25, specifically in the space formed by the outer peripheral surface of the coarse filter 25 and the inner peripheral surface of the catalyst unit 20. The coarse filter 25 has a slit structure with a slit width of 0.5 mm or less. The resin layer in the coarse filter 25 has varying contact times depending on the flow path and is therefore not used for performance purposes. Therefore, while only catalyst metal-supported resin 23 can be filled within the catalyst unit 20, for cost considerations, a laminated or mixed-bed state is preferred. In particular, as Figure 3As shown, more preferably, a stacked configuration in which the catalyst metal-loaded resin 23 is filled on the inlet side and the filler 24 is filled on the outlet side (bottom surface within the catalyst device 20) is adopted. As the filler 24, filling is performed in order to bury the filter 25, and thus there is no particular limitation as long as it does not affect activated carbon, sand, beads, ion exchange resin, and the like, and water quality.

[0044] From the viewpoint of the treated water quality, the layer height of the catalyst metal-loaded resin 23 is preferably 50 cm or more.

[0045] The treated water is added with hydrogen by the hydrogen addition device 10 before being supplied to the oxidizing substance removal device 11. The amount of hydrogen addition is an amount required for the decomposition of the oxidizing substance, and from the viewpoint of the water quality of the ultrapure water, it is necessary to be an amount that is not excessive, and thus it is necessary to be controlled within a certain range. On the other hand, the control method is preferably simpler.

[0046] Therefore, in the present embodiment, the oxidizing substance removal device 11 is configured to be controlled in such a manner that the hydrogen addition amount of the hydrogen addition device 10 is adjusted, a concentration measuring unit 21 is provided at the outlet of the catalyst device 20, and the dissolved hydrogen concentration of the treated water is measured. The control unit 22 has a configuration in which the hydrogen addition amount of the hydrogen addition device is adjusted based on the dissolved hydrogen concentration measured by the concentration measuring unit 21. Specifically, the control unit 22 preferably adjusts the hydrogen addition amount of the hydrogen addition device 10 so that the dissolved hydrogen concentration (DH) of the treated water at the outlet of the catalyst device 20 converges to a set value range (10 μg / L or less). Note that, for example, by controlling the hydrogen addition amount to be more than the theoretical value, it is also possible to cope with a sharp increase in the dissolved oxygen concentration in raw water. Note that, with respect to the treated water quality treated by the oxidizing substance removal device 11, the dissolved oxygen concentration (DO) in the treated water is preferably 10 μg / L or less, and the dissolved hydrogen concentration (DH) is preferably 10 μg / L or less.

[0047] As the concentration measuring unit 21, titration, fluorescence, and a concentration measuring unit of a diaphragm electrode type can be given, but as long as it is possible to measure dissolved oxygen and dissolved hydrogen, it is not limited to the concentration measuring units of the above-described methods. Among them, from the viewpoint of measurement accuracy and the ability to measure on line, the diaphragm electrode method is preferable.

[0048] The treated water is preferably supplied to the oxidizing substance removal device 11 (catalyst device 20) at a speed of LV (linear velocity) 30 or more, particularly LV 100 or more. If the water supply speed LV is slow, even if the hydrogen addition amount is changed, it takes time to reach the catalyst, and the control difficulty increases. In addition, the more the amount of water that can be treated by the oxidizing substance removal device 11 (catalyst device 20), the more the number of units required can be suppressed, and the more the ultrapure water can be manufactured at a low cost.

[0049] According to the above structure, a water treatment device and a water treatment method can be provided that can stably remove oxidizing substances such as oxygen and hydrogen peroxide in a catalyst device and can stably obtain good treated water quality.

[0050] Moreover, the ultrapure water obtained by such a water treatment device and water treatment method is high-purity ultrapure water from which organic substances, hydrogen peroxide, dissolved gases (such as oxygen), ionic substances (impurities), and fine particles have been removed, and is suitable for cleaning electronic components and manufacturing equipment for electronic components.

[0051] Examples [1] Regarding the systems used in the examples and comparative examples Assemble Figure 4 The system shown.

[0052] As a container filled with a catalyst metal-supported resin, an ion exchange resin container (column) with an inner diameter of 31 mm and a height of 1 m was prepared and filled with a catalyst metal-supported resin for use. The catalyst metal-supported resin is manufactured by ORGANO.

[0053] The hydrogen addition device uses the trade name: Acid Reduction King, manufactured by ORGANO.

[0054] The concentration measuring device uses Orbisphere 510, the DH sensor uses 31230s.01, and the DO sensor uses 31120JP.01.

[0055] As Figure 4 As described, in the laboratory scale, the convection time is short, so a mixing column is provided to mix the added dissolved hydrogen well, but in the case of an actual machine, it is not necessarily required.

[0056] [2] Verification of the definition of resin type Prepare treated water with a dissolved oxygen (DO) concentration ≤ 10 μg / L and a H2O2 content of 35 μg / L. Additionally, prepare a column filled with an OH-type platinum group metal-supported catalyst with a layer height of 10 cm in the aforementioned column. The platinum group metal-supported catalyst is manufactured by ORGANO.

[0057] Then, the above-mentioned treated water was passed through the above-mentioned column at a water flow rate of LV425, and the correlation between the OH-type ratio after passing through and the H2O2 removal performance was evaluated. The results are shown in Figure 5 . According to Figure 5 , if the proportion of the OH-type in the resin type is 60% or less, the H2O2 content in the treated water exceeds 1 μg / L, so the resin at that time is defined as the carbonate type.

[0058] [3] Comparative evaluation of control methods A treated water having a dissolved oxygen (DO) concentration of 10 μg / L or less and a content of H2O2 of 35 μg / L was prepared. In addition, a column in which an OH type platinum group metal supported catalyst was packed at a bed height of 10 cm in the aforementioned column was prepared. The catalyst metal supported resin was manufactured by ORGANO. Then, for the following two control methods: a control method in which the above treated water was passed through the above column at a water passing speed of LV425, the dissolved hydrogen (DH) concentration of the treated water (outlet water) of the metal catalyst supported resin column was measured, and the hydrogen addition amount to the treated water of the metal catalyst supported resin column was controlled so that the dissolved hydrogen (DH) concentration became a set value (hereinafter also referred to as "DH control"); and a control method in which the dissolved oxygen (DO) concentration of the treated water (outlet water) of the metal catalyst supported resin column was measured, and the hydrogen addition amount to the treated water of the metal catalyst supported resin column was controlled so that the dissolved oxygen (DO) concentration became a set value (hereinafter also referred to as "DO control"), the dissolved hydrogen (DH) concentration in the treated water of both was compared. The results are shown in Figure 6 . As shown in Figure 6 , it was confirmed that the water quality of the treated water of the DH control (control of the hydrogen addition amount to the treated water of the column so that the DH concentration of the treated water of the column became a set value) was further improved compared to the case where the DO control (control of the hydrogen addition amount to the treated water of the column so that the DO concentration of the treated water of the column became a set value) was performed.

[0059] 〔4〕Evaluation of the bed height of the catalyst metal supported resin A treated water having a dissolved oxygen (DO) concentration of 2000 μg / L and a content of H2O2 of 35 μg / L was prepared. In addition, a column in which a carbonate type platinum group metal supported catalyst was packed at a bed height of 30 cm in the aforementioned column, and a column in which only the bed height was changed to 50 cm were prepared. The carbonate type platinum group metal supported catalyst was manufactured by ORGANO.

[0060] Then, the above treated water was passed through the aforementioned column in which the bed height was changed at a water passing speed of LV100, and the water quality of the treated water after the passage based on the difference in the bed height was evaluated. The results are shown in Figure 7 .

[0061] According to Figure 7 , it was confirmed that the water quality of the treated water in the case where the bed height was set to 50 cm was further improved compared to the case where the bed height was set to 30 cm.

[0062] 〔5〕Evaluation of the water passing speed LV of the treated water Prepare water to be treated with a dissolved oxygen (DO) concentration of 3500 μg / L and an H2O2 content of 35 μg / L. Also prepare a column filled with a carbonate-type platinum group metal supported catalyst in a 50 cm high layer. The carbonate-type platinum group metal supported catalyst was prepared using ORGANO.

[0063] Then, the flow rate of the treated water was varied to LV30, 50, 80, and 110, respectively, and water quality of the treated water after flow was evaluated based on the differences in LV. The results are shown below. Figure 8 .

[0064] according to Figure 8 It was confirmed that any LV met the water quality standards (dissolved oxygen concentration below 10 μg / L and dissolved hydrogen concentration below 10 μg / L), and the stability of the treated water quality improved with the increase of LV.

[0065] The present invention has been described above with reference to the embodiments, but the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art regarding the structure and details of the present invention can be made within the scope of the present invention.

[0066] This application claims priority based on Japanese Patent Application No. 2023-066546, filed on April 14, 2023, the entire contents of which are hereby incorporated.

[0067] Symbol Explanation 1: Water treatment equipment 2: Pre-treatment device 3: Pure water tank 4: K Tower 5: D Tower (Pre-processing) 6: Tower A 7: Reverse osmosis membrane unit 8: Secondary pure water tank 9: Ultraviolet Oxidation Device 10: Hydrogen addition device 11: Oxidizing substance removal device 12: Sub-jar 13: Pump 14: Heat exchange device 15: Ultraviolet Oxidation Device 16: Catalytic reaction unit 17: Non-regenerative mixed-bed ion exchange unit (cylinder polishing machine) 18: Ultrafiltration device 19: Point of Use 20: Catalyst Unit 21: Concentration Measurement Unit 22: Control unit 23: Catalyst metal-supporting resin 24: Filler 25: Coarse filter 26: Primary pure water manufacturing device 27: Secondary pure water manufacturing device (subsystem)

Claims

1. A water treatment device, characterized in that, The water treatment device has the following features: A hydrogen addition device that adds hydrogen to treated water containing at least hydrogen peroxide; and The oxidizing agent removal device receives the treated water, which has been hydrogenated by the hydrogen addition device, as flowing into it. The oxidizing substance removal device has: A catalyst device comprising a catalyst metal-supported resin, the catalyst metal-supported resin removing hydrogen peroxide from the treated water by contacting the treated water obtained by adding hydrogen from the hydrogen addition device; A concentration measuring unit measures the dissolved hydrogen concentration of the water after it has been treated by the catalyst device. as well as The control unit controls the amount of hydrogen added by the hydrogen adding device based on the dissolved hydrogen concentration measured by the concentration measuring unit. The catalyst metal-supported resin is a catalyst metal-supported resin that supports a platinum group metal catalyst on a carbonate-type anion exchange resin.

2. The water treatment apparatus according to claim 1, wherein, The control unit controls the amount of hydrogen added by the hydrogen addition device so that the dissolved hydrogen concentration in the treated water after treatment by the oxidizing substance removal device is below 10 μg / L.

3. The water treatment apparatus according to claim 1, wherein, The catalyst metal-supported resin layer filling the catalyst device has a height of 30 cm or more.

4. The water treatment apparatus according to claim 1, wherein, The flow rate of the treated water after hydrogen is added by the hydrogen addition device to the oxidizing substance removal device is LV30 or higher.

5. The water treatment apparatus according to claim 1, wherein, The catalyst device comprises: a coarse filter that inhibits the outflow of ion exchange resin filled inside the device to the outside of the device; and a packing material that is filled in such a way as to bury the coarse filter, wherein the catalyst metal-supported resin is stacked on top of the packing material.

6. The water treatment apparatus according to claim 1, wherein, The dissolved oxygen concentration of the treated water after treatment by the oxidizing substance removal device is less than 10 μg / L, and the dissolved hydrogen concentration is less than 10 μg / L.

7. The water treatment apparatus according to claim 1, wherein, The water treatment device is installed in the primary pure water production unit of the ultrapure water production unit.

8. A water treatment method comprising an oxidizing substance removal step for removing oxidizing substances from the water to be treated, characterized in that, The oxidizing substance removal process includes: The process of adding hydrogen to the water being treated; and The process of passing the treated water, after the addition of hydrogen, into a catalyst apparatus equipped with a catalyst metal-supported resin. In the process of adding hydrogen to the water being treated, the amount of hydrogen added is controlled so that the dissolved hydrogen concentration in the water being treated at the outlet of the catalyst device reaches a set value. The catalyst metal-supported resin is a catalyst metal-supported resin that supports a platinum group metal catalyst on a carbonate-type anion exchange resin.

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