Ultra-pure water production apparatus and ultra-pure water production method

Abstract

This invention provides an ultrapure water production apparatus capable of providing a long-term, stable supply of high-quality ultrapure water. The ultrapure water production apparatus is characterized by comprising a primary pure water production unit and a secondary pure water production unit. The primary pure water production unit includes a first ultraviolet oxidation unit, and the secondary pure water production unit includes a second ultraviolet oxidation unit and a hydrogen peroxide removal unit disposed downstream of the second ultraviolet oxidation unit. The hydrogen peroxide removal unit includes an ion exchanger loaded with a platinum group metal catalyst. The ultraviolet irradiation intensity of the second ultraviolet oxidation unit is controlled to ensure that the TOC value of the supply water to the second ultraviolet oxidation unit is... SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation device (TOC) TRE The difference ΔTOC(TOC) SUP TOC TRE The value is below 1 ppb.

Description

Technical Field

[0001] This invention relates to an ultrapure water manufacturing apparatus and a method for producing ultrapure water. Background Technology

[0002] In recent years, with the increasing demands for ultrapure water quality, methods for decomposing and removing trace amounts of organic matter in water have been studied. TOC (Total Organic Carbon) is used as an indicator of water quality after the decomposition and removal of organic matter, and a TOC level below a certain benchmark is required.

[0003] One method for decomposing and removing trace amounts of organic matter from water is ultraviolet (UV) oxidation treatment. UV oxidation decomposes water into OH radicals, which then oxidize and decompose organic matter (TOC components).

[0004] However, during ultraviolet oxidation, the remaining OH radicals generated from water decomposition associate, producing hydrogen peroxide. Hydrogen peroxide degrades resin materials such as ion exchange resins installed downstream of the ultraviolet oxidation unit, leading to a decrease in the performance of the ultrapure water production equipment. Furthermore, the degradation of resin materials such as ion exchange resins generates new resin-derived organic matter, resulting in a decrease in the quality of the ultrapure water.

[0005] Therefore, as a method for removing hydrogen peroxide from water, a method using platinum group metal supported catalysts, where platinum group metals, represented by palladium (Pd) and platinum (Pt), are supported on a carrier, has been proposed. By using a platinum group metal supported catalyst, hydrogen peroxide can be decomposed and removed via a reaction represented by 2H₂O₂ → 2H₂O + O₂.

[0006] Patent Document 1 discloses a method and apparatus for producing ultrapure water using such a method for removing hydrogen peroxide. This method involves treating water with ultraviolet light using an ultraviolet oxidation device, followed by hydrogen peroxide removal using a hydrogen peroxide removal device with a specific platinum-based catalyst. More specifically, it describes a method and apparatus for producing pure water, characterized in that the platinum-based catalyst is formed by loading platinum-based metal colloidal particles onto anion exchange resin; the TOC of the water supplied to the ultraviolet oxidation device is set to 5 ppb or less; the inorganic carbonate ion concentration of the water supplied to the ultraviolet oxidation device is less than 1 ppb; and the inorganic carbonate ion concentration of the treated water after treatment by the ultraviolet oxidation device is 1 ppb or more. The objective is to provide a method and apparatus for producing pure water that can prevent (or inhibit) the deterioration of the catalyst resin and stably decompose hydrogen peroxide over a long period.

[0007] In addition, Patent Document 2 discloses a method and apparatus for reducing hydrogen peroxide, which involves contacting treated water containing hydrogen peroxide with a catalyst resin formed by loading platinum group metals onto a strongly basic anion exchange resin, thereby reducing the hydrogen peroxide content in the treated water.

[0008] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 5854163 Patent Document 2: Japanese Patent Application Publication No. 2010-069460 Summary of the Invention

[0009] The technical problem that the invention aims to solve In Patent Document 1, as an effect of the invention, it is described that by setting the TOC of the water supplied to the UV oxidation device to 5 ppb or below, the concentration of organic acids is reduced, which can prevent poisoning (deterioration) of the platinum-based catalyst used for hydrogen peroxide removal in the downstream stage of the UV oxidation device and extend the catalyst's lifespan. Furthermore, it is described that by setting the UV oxidation treatment conditions so that the concentrations of inorganic carbonate ions in the water supplied to and from the UV oxidation device are within specific ranges, the proportion of organic matter decomposed into CO2 is increased (i.e., the organic matter concentration is reduced).

[0010] However, the method described in Patent Document 1 requires the concentration of inorganic carbonate ions in the treated water after UV oxidation to be at least a specified level, leaving room for further extending the catalyst life. Specifically, the inventors discovered the following problem: inorganic carbonate ions affect the degradation of the platinum-based catalyst-supported resin. When the concentration of inorganic carbonate ions increases, the platinum-based catalyst-supported resin deteriorates, resulting in a decrease in the quality of the obtained ultrapure water. More specifically, it was found that during UV oxidation treatment, organic matter (TOC components) is oxidized and decomposed to generate organic acids, which are then oxidized and decomposed to generate CO2. This CO2 dissolves in the treated water to become inorganic carbonate ions, resulting in an increase in the concentration of inorganic carbonate ions in the treated water and degradation of the platinum-based catalyst-supported resin.

[0011] The purpose of this invention is to solve the technical problems in view of the above, namely, to provide an ultrapure water manufacturing apparatus and an ultrapure water manufacturing method that can stably supply high-quality ultrapure water over a long period of time.

[0012] Technical solutions for solving technical problems The present invention includes the following methods.

[0013] [1] An ultrapure water manufacturing apparatus, characterized in that it comprises a primary pure water manufacturing apparatus and a secondary pure water manufacturing apparatus. The primary pure water production device includes a first ultraviolet oxidation device. The secondary pure water production device includes a second ultraviolet oxidation device and a hydrogen peroxide removal device located downstream of the second ultraviolet oxidation device. The hydrogen peroxide removal device includes an ion exchanger supported on a platinum group metal catalyst. The amount of ultraviolet radiation from the second ultraviolet oxidation device is controlled to ensure that the TOC value of the supply water supplied to the second ultraviolet oxidation device is [value missing]. SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation device (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE The value is below 1 ppb.

[0014] [2] According to the ultrapure water manufacturing apparatus described in [1], the amount of ultraviolet irradiation of the first ultraviolet oxidation device is controlled such that the TOC value of the supply water supplied to the second ultraviolet oxidation device is (TOC). SUP Satisfy 0 <TOC SUP ≤5ppb.

[0015] [3] According to the ultrapure water manufacturing apparatus described in [1] or [2], the ultraviolet irradiation of the first ultraviolet oxidation device is greater than the ultraviolet irradiation of the second ultraviolet oxidation device.

[0016] [4] The ultrapure water manufacturing apparatus according to any one of [1] to [3], wherein the ultraviolet irradiation amount of the first ultraviolet oxidation device and the ultraviolet irradiation amount of the second ultraviolet oxidation device are controlled such that the TOC value of the treated water after treatment by the second ultraviolet oxidation device is (TOC TRE The value is below 1 ppb.

[0017] [5] An ultrapure water manufacturing apparatus according to any one of [1] to [4], wherein a water quality meter is provided before and / or after the second ultraviolet oxidation apparatus.

[0018] [6] An ultrapure water manufacturing apparatus according to any one of [1] to [5], wherein the ultrapure water manufacturing apparatus comprises: a first TOC meter disposed in front of the second ultraviolet oxidation device; and a second TOC meter disposed after the second ultraviolet oxidation device.

[0019] [7] A method for producing ultrapure water, characterized in that an ultrapure water production device equipped with a primary pure water production device and a secondary pure water production device is used. The primary pure water production device includes a first ultraviolet oxidation device. The secondary pure water production device includes a second ultraviolet oxidation device and a hydrogen peroxide removal device located downstream of the second ultraviolet oxidation device. The hydrogen peroxide removal device includes an ion exchanger supported on a platinum group metal catalyst. The amount of ultraviolet radiation used to operate the second ultraviolet oxidation device is such that the TOC value of the supply water supplied to the second ultraviolet oxidation device is reduced to a certain level. SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation device (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE The value is below 1 ppb.

[0020] [8] According to the ultrapure water manufacturing method described in [7], the ultraviolet irradiation intensity of the first ultraviolet oxidation device is adjusted such that the TOC value of the supply water supplied to the second ultraviolet oxidation device is reduced to a certain level. SUP Satisfy 0 <TOC SUP ≤5ppb.

[0021] [9] The ultrapure water manufacturing method according to [7] or [8] is operated in such a way that the ultraviolet irradiation of the first ultraviolet oxidation device is greater than the ultraviolet irradiation of the second ultraviolet oxidation device.

[0022]

[10] The ultrapure water manufacturing method according to any one of [7] to [9], wherein the ultraviolet irradiation of the first ultraviolet oxidation device and the ultraviolet irradiation of the second ultraviolet oxidation device are operated such that the TOC value of the treated water after treatment by the second ultraviolet oxidation device is (TOC TRE The value is below 1 ppb.

[0023]

[11] The ultrapure water manufacturing method according to any one of [7] to

[10] , wherein the ultrapure water manufacturing apparatus has a water quality meter disposed before and after the second ultraviolet oxidation apparatus.

[0024]

[12] The ultrapure water manufacturing method according to any one of [7] to

[11] , wherein the ultrapure water manufacturing apparatus comprises: a first TOC meter disposed in front of the second ultraviolet oxidation apparatus; and a second TOC meter disposed after the second ultraviolet oxidation apparatus.

[0025] Invention Effects According to the present invention, an ultrapure water manufacturing apparatus and an ultrapure water manufacturing method capable of providing a stable supply of high-quality ultrapure water over a long period of time can be provided. Attached Figure Description

[0026] Figure 1 This is a simplified structural diagram of an example of an ultrapure water manufacturing apparatus according to one embodiment of the present invention.

[0027] Figure 2 This is a graph showing the correlation between the OH form ratio of the catalyst resin in the hydrogen peroxide removal device and the hydrogen peroxide removal performance.

[0028] Figure 3 This is a simplified structural diagram of the ion exchange resin container (hydrogen peroxide removal device) filled with catalyst resin used in Experimental Example 1. Detailed Implementation

[0029] The preferred embodiments of the present invention will be described below.

[0030] One embodiment of the present invention relates to an ultrapure water manufacturing apparatus comprising a primary pure water manufacturing apparatus (Make-up) and a secondary pure water manufacturing apparatus (Polishing) for supplying treated water from the primary pure water manufacturing apparatus.

[0031] The primary pure water production apparatus has a first ultraviolet oxidation device, and the secondary pure water production apparatus has a second ultraviolet oxidation device and a hydrogen peroxide removal device disposed after the second ultraviolet oxidation device.

[0032] The first and second ultraviolet oxidation devices are used to decompose and remove trace amounts of organic matter (TOC components) from water through ultraviolet oxidation treatment. In this ultraviolet oxidation treatment, water is oxidized and decomposed to generate OH radicals, which then oxidize and decompose the organic matter (TOC components). At this time, the generated organic acids are further oxidized and decomposed to generate CO2, forming inorganic carbonate ions in the treated water. On the other hand, hydrogen peroxide is generated through the association of the remaining OH radicals.

[0033] A hydrogen peroxide removal device is a catalyst device equipped with an ion exchanger supported on a platinum group metal catalyst (hereinafter, appropriately referred to as a "catalyst support") to decompose and remove hydrogen peroxide. This hydrogen peroxide removal device (hereinafter, appropriately referred to as a "catalyst device") removes hydrogen peroxide generated by ultraviolet oxidation treatment through the action of a catalyst.

[0034] This embodiment of the ultrapure water manufacturing apparatus controls the amount of ultraviolet radiation from the second ultraviolet oxidation device to ensure that the TOC value of the supply water supplied to the second ultraviolet oxidation device is [missing value]. SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation unit (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE The value is below 1 ppb.

[0035] Here, "control" includes either automatic control or manual control.

[0036] In addition, the feed water supplied to the second ultraviolet oxidation unit contains TOC (TOC). SUP (≠0), the TOC of the water supply SUP TOC of water treatment TRE The relationship is TOC SUP TOC TRE (i.e., 0 < ΔTOC).

[0037] Furthermore, another embodiment of the present invention relates to an ultrapure water manufacturing method that uses such an ultrapure water manufacturing apparatus, wherein the ultraviolet irradiation intensity of the second ultraviolet oxidation device is adjusted such that the TOC value of the supply water supplied to the second ultraviolet oxidation device is reduced. SUP The TOC value of the water treated by the second ultraviolet oxidation unit (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE The value is below 1 ppb.

[0038] Here, "operation" includes either automatic control-based operation or manual operation.

[0039] Furthermore, as mentioned above, the supply water supplied to the second ultraviolet oxidation device contains TOC (TOC content). SUP (≠0), the TOC of the water supply SUP TOC of water treatment TRE The relationship is TOC SUP TOC TRE (i.e., 0 < ΔTOC).

[0040] As described above, by adjusting the TOC value (TOC) of the supply water supplied to the second ultraviolet oxidation device... SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation unit (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE By controlling or operating the system to a concentration of less than 1 ppb, the concentration of inorganic carbonate ions in the effluent from the second ultraviolet oxidation unit can be suppressed to a certain level. Therefore, the degradation of the catalyst support in the downstream hydrogen peroxide removal unit caused by inorganic carbonate ions can be suppressed, and a stable supply of ultrapure water with high purity can be achieved (operating in a way that minimizes water quality fluctuations).

[0041] In this invention, it is necessary to control or operate the amount of ultraviolet radiation so that the ΔTOC is less than 1 ppb, preferably less than 0.5 ppb, and more preferably less than 0.2 ppb.

[0042] It should be noted that if all 1 ppb of TOC is decomposed, then 1 ppb of TOC is equivalent to an inorganic carbonate ion concentration of 5 ppb under the following conditions.

[0043] If all organic matter (TOC) in the water is decomposed, it will eventually break down into water and carbon dioxide (C). x H y O z →CO2 + H2O), the generated carbon dioxide dissolves in water to produce inorganic carbonate ions (HCO3-). - CO3 2- If all the generated carbon dioxide dissolves in water, and all the dissolved carbon dioxide becomes inorganic carbonate ions, then the mass ratio of carbon (C) in the organic component (TOC component) to the generated inorganic carbonate ions is approximately 1:5.

[0044] [TOC component (C)]: [Inorganic carbonate ions (HCO3-)] - )]=12:(1+12+16×3)≈1:5 [TOC component (C)]: [Inorganic carbonate ions (CO3)] 2- )]=12:(12+16×3)=1:5 The TOC value of the supply water to the second ultraviolet oxidation unit (TOC) SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation unit (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE When the value is set to 1 ppb or less, it is preferable to perform ultraviolet oxidation treatment on the water to be treated with a sufficiently high irradiation dose in the first ultraviolet oxidation device, so as to sufficiently reduce the TOC value of the supply water supplied to the subsequent second ultraviolet oxidation device in advance. SUP ).

[0045] At this point, it is preferable that the ultraviolet irradiation dose of the first ultraviolet oxidation device is greater than that of the second ultraviolet oxidation device.

[0046] Typically, to reduce the TOC value of the final treated water, the UV irradiation intensity of the UV oxidation unit (second UV oxidation unit) in the downstream secondary pure water production unit is increased to fully decompose the TOC components. However, if a large amount of TOC components are decomposed at this time, the amount of inorganic carbonate ions produced will increase. As a result, problems caused by inorganic carbonate ions (deterioration of the catalyst support in the hydrogen peroxide removal unit) are likely to occur.

[0047] Therefore, in this invention, it is preferable to increase the UV irradiation intensity of the UV oxidation unit (first UV oxidation unit) in the upstream primary pure water production unit to sufficiently reduce the TOC value beforehand, thereby reducing the amount of TOC required for decomposition in the UV oxidation unit (second UV oxidation unit) of the downstream secondary pure water production unit. This suppresses the generation of inorganic carbonate ions in the downstream secondary pure water production unit, and consequently, suppresses the deterioration of the catalyst support in the hydrogen peroxide removal unit caused by inorganic carbonate ions.

[0048] In the ultrapure water manufacturing apparatus and method of the present invention, from the viewpoint of more sufficiently reducing the amount of TOC components oxidized and decomposed in the second ultraviolet oxidation unit, it is preferable to control (or operate) the ultraviolet irradiation intensity of the first ultraviolet oxidation unit so that the TOC value of the supply water supplied to the second ultraviolet oxidation unit is reduced. SUP ) is below 5 ppb (0 < TOC) SUP ≤5ppb), preferably 3ppb or less (0 < TOC) SUP ≤3ppb).

[0049] Furthermore, from the viewpoint of not only sufficiently reducing the TOC of the final treated water, but also sufficiently reducing the amount of TOC components oxidized and decomposed by the second ultraviolet oxidation unit, it is preferable to control (or operate) the ultraviolet irradiation intensity of the first ultraviolet oxidation unit and the ultraviolet irradiation intensity of the second ultraviolet oxidation unit so that the TOC value of the treated water after treatment by the second ultraviolet oxidation unit is reduced. TRE The value is below 1 ppb.

[0050] It should be noted that even if TOC is excessively reduced in the primary pure water production unit, organic matter may still contaminate the treated water, causing an increase in TOC. This increase can be removed in the secondary pure water production unit. Therefore, excessive TOC reduction is unnecessary in the primary pure water production unit. From the viewpoint of treatment efficiency, it is preferable to appropriately reduce TOC based on the TOC content in the treated water. From the viewpoint of suppressing excessive ultraviolet irradiation in the first ultraviolet oxidation unit, the control or operation of the ultraviolet irradiation amount of the first ultraviolet oxidation unit is preferably based on the TOC value of the supply water supplied to the second ultraviolet oxidation unit. SUPThe exposure is carried out within a range of ultraviolet radiation doses of 0.3 ppb or more (without being reduced to a range of radiation doses less than 0.3 ppb), more preferably within a range of ultraviolet radiation doses of 0.5 ppb or more (without being reduced to a range of radiation doses less than 0.5 ppb), or within a range of ultraviolet radiation doses of 1 ppb or more (without being reduced to a range of radiation doses less than 1 ppb).

[0051] TOC measurement can be performed by setting up TOC meters between the first and second UV oxidation units, and after the second UV oxidation unit. This allows for the measurement of TOC in the treated water between the first and second UV oxidation units, as well as in the treated water after the second UV oxidation unit.

[0052] Alternatively, the TOC meter can be installed either between the first and second UV oxidation units, or downstream of the second UV oxidation unit, to measure the TOC of the treated water between the first and second UV oxidation units, and the TOC of the treated water downstream of the second UV oxidation unit. Thus, a single TOC meter can measure the TOC of the treated water from both units.

[0053] Thus, in the ultrapure water manufacturing apparatus and ultrapure water manufacturing method of the present invention, TOC can be determined by one or two TOC meters to measure the TOC of the treated water between the first ultraviolet oxidation unit and the second ultraviolet oxidation unit, as well as the TOC of the treated water after the second ultraviolet oxidation unit.

[0054] Regarding the determination of TOC in the treated water between the first and second ultraviolet oxidation units, a more accurate measurement value (TOC) was obtained. SUP From the perspective of ), it is preferable to measure the supply water (i.e., the treatment water between the second ultraviolet oxidation unit and the treatment unit located immediately in front of it) before it is supplied to the second ultraviolet oxidation unit.

[0055] On the other hand, regarding the location for measuring the TOC of the treated water after the second ultraviolet oxidation unit, as will be described later, there are no particular restrictions as long as it is after the second ultraviolet oxidation unit. However, from the viewpoint of simplifying the equipment, it is preferable to measure the TOC of the treated water from the final treatment unit of the secondary pure water production unit. This allows for the simultaneous acquisition of the TOC value (TOC) used to calculate ΔTOC. TRE (and the TOC value of the final treated water produced using ultrapure water manufacturing equipment).

[0056] By setting up a TOC meter in this way, the TOC of the treated water between the first and second ultraviolet oxidation devices, as well as the TOC of the treated water after the second ultraviolet oxidation device, can be measured. Based on these TOC measurements, the amount of ultraviolet radiation to the first and second ultraviolet oxidation devices can be controlled (or operated).

[0057] For example, the amount of ultraviolet radiation from the first and second ultraviolet oxidation devices can be controlled (or operated) so that the first TOC value (TOC) is obtained. SUP The measured TOC value of the effluent from the first ultraviolet oxidation unit and the second TOC value (TOC TRE The difference (ΔTOC) between the measured TOC values ​​of the effluent from the second ultraviolet oxidation unit and the measured TOC values ​​is less than 1 ppb.

[0058] At this time, by performing ultraviolet oxidation treatment with a sufficiently high irradiation dose in the first ultraviolet oxidation device to bring the first TOC value to a predetermined value or below (e.g., 5 ppb or below), the amount of organic matter in the supply water supplied to the subsequent second ultraviolet oxidation device can be sufficiently reduced. In addition, the ultraviolet irradiation dose of the first and second ultraviolet oxidation devices can be controlled (or operated) to bring the second TOC value to a predetermined value or below (e.g., 1 ppb or below).

[0059] As a TOC meter, a conventional TOC meter used in the production of ultrapure water can be used. For example, a fully oxidized TOC meter can be used, which can guide a portion of the treated water to the measuring cell, close the valve, irradiate it with ultraviolet light, and convert the difference between the conductivity at the moment when the conductivity becomes constant after complete oxidation and the conductivity before ultraviolet irradiation into a TOC value.

[0060] In the ultrapure water manufacturing apparatus of the present invention, various water quality meters other than the TOC meter can be installed at desired locations. Based on the measurements of the water quality meters, water quality management, control, and operation of various treatment devices constituting the ultrapure water manufacturing apparatus are possible.

[0061] For example, conductivity can be measured using a water quality meter, and the UV irradiation dose of the first UV oxidation device or / and the second UV oxidation device can be adjusted based on this measurement. The water quality meter can be installed between the first and second UV oxidation devices, or downstream of the second UV oxidation device, or either. Alternatively, a single water quality meter can be used to measure both the water quality of the treated water between the first and second UV oxidation devices and the water quality of the treated water downstream of the second UV oxidation device.

[0062] The configuration of the ultrapure water manufacturing apparatus of the present invention will be further described below.

[0063] Figure 1 This illustrates an example of the configuration of an ultrapure water manufacturing apparatus according to one embodiment of the present invention, but the present invention is not limited to this configuration.

[0064] like Figure 1 As shown, the ultrapure water production apparatus sequentially comprises a primary pure water production unit 1 and a secondary pure water production unit 2. The primary pure water production unit 1 sequentially comprises a first ultraviolet oxidation unit 11, an ion exchange unit 12, a boron selective resin unit 13, and a degassing unit 14. The secondary pure water production unit 2 sequentially comprises a second ultraviolet oxidation unit 21, a hydrogen peroxide removal unit (catalyst unit) 22, a degassing unit 23, an ion exchange unit 24, and an ultrafiltration membrane unit 25.

[0065] As described above, the TOC meter can be installed between the first ultraviolet oxidation device 11 and the second ultraviolet oxidation device 21, and / or after the second ultraviolet oxidation device 21. Figure 1 In the ultrapure water manufacturing apparatus shown, a TOC meter 31 is installed before the second ultraviolet oxidation device 21, and a TOC meter 32 is installed after the final treatment device of the secondary pure water manufacturing apparatus 2.

[0066] In the determination of TOC, the first TOC value (TOC SUP The measured value of the supply water supplied to the second ultraviolet oxidation device 21 can be used as the second TOC value (TOC). TRE The device can use the measured value of the treated water after treatment by the second ultraviolet oxidation device 21 (the measured value of the effluent from the second ultraviolet oxidation device 21 or the measured value of the effluent from each treatment device installed after the second ultraviolet oxidation device). The difference between the first TOC value and the second TOC value is set as ΔTOC, and the ultraviolet irradiation of the first and second ultraviolet oxidation devices can be controlled or operated so that the ΔTOC is less than 1 ppb.

[0067] The location of the TOC meter on the post-stage side is not particularly restricted as long as it is after the second ultraviolet oxidation device 21. However, from the perspective of simplifying the equipment, such as Figure 1 As shown, the TOC meter 32 is preferably installed downstream of the final treatment unit of the secondary pure water production unit 2. This allows for the measurement of the TOC value of the final treated water from the ultrapure water production unit, and the measured value can be used as a second TOC value (TOC2) for calculating ΔTOC. TRE ).

[0068] It should be noted that after the second ultraviolet oxidation device 21 in the secondary pure water production device 2, the TOC leaching in the various treatment devices and equipment in the secondary pure water production device 2 is trace, so the influence of the TOC meter setting position on ΔTOC can be ignored.

[0069] In addition, Figure 1 In the configuration shown, two TOC meters are provided. However, the pre-stage TOC meter 31 can be omitted, and only the post-stage TOC meter 32 can be provided, so that a portion of the supply water supplied to the second ultraviolet oxidation device 21 can be introduced into the post-stage TOC meter 32. Thus, the TOC of the supply water supplied to the second ultraviolet oxidation device 21 and the TOC of the treated water after treatment by the second ultraviolet oxidation device 21 can be measured using a single TOC meter.

[0070] It should be noted that, in Figure 1 The configuration shown does not include a pretreatment unit (pretreatment system), but it can be incorporated into the ultrapure water production apparatus as needed. Alternatively, pretreated water from the pretreatment unit (pretreatment system) can be supplied to the primary pure water production unit of the ultrapure water production apparatus. The pretreatment unit (pretreatment system) can perform pretreatment processes such as coagulation, pressurized flotation, and filtration.

[0071] (Pure water production unit) The primary pure water production unit of the ultrapure water production apparatus of this embodiment may include a first ultraviolet oxidation unit, and may further selectively include treatment units commonly used in ultrapure water production apparatuses, such as ion exchange units (e.g., regeneration type ion exchange units), boron selective resin units, degassing units (e.g., membrane degassing units), and reverse osmosis membrane units (RO units).

[0072] For example, as mentioned above Figure 1 As shown, the primary pure water production apparatus 1 may have a configuration in which a first ultraviolet oxidation device 11, an ion exchange device 12 (e.g., a regenerable ion exchange resin), a boron selective resin device 13, and a degassing device 14 (e.g., a membrane degassing device) are connected in sequence.

[0073] In the first ultraviolet oxidation device 11, organic matter is oxidized and decomposed; in the ion exchange device 12, impurity ions in the water are removed; in the boron-selective resin device 13, boron in the water is removed; and in the degassing device 14, dissolved oxygen and other gases in the water are removed. The boron-selective resin device 13 can be omitted if necessary. Furthermore, a reverse osmosis membrane device can be further installed to remove inorganic matter, organic matter, particles, microorganisms, etc., from the water.

[0074] (Secondary pure water production unit) The secondary pure water production unit of the ultrapure water production apparatus of this embodiment has a second ultraviolet oxidation unit and a subsequent hydrogen peroxide removal unit (catalyst unit). Furthermore, it is possible to appropriately select treatment units commonly used in ultrapure water production apparatuses, such as degassing units (e.g., membrane degassing units), ion exchange units (e.g., non-regenerative ion exchange units such as cylindrical polishing machines), and ultrafiltration membrane units (UF).

[0075] For example, as mentioned above Figure 1 As shown, the secondary pure water production apparatus 2 can have a configuration in which a second ultraviolet oxidation unit 21, a hydrogen peroxide removal unit 22, a degassing unit 23 (e.g., a membrane degassing unit), an ion exchange unit 24 (e.g., a non-regenerative ion exchange unit), and an ultrafiltration membrane unit 25 are connected in sequence. Depending on the needs, the arrangement order of the degassing unit 23 and the ion exchange unit 24 can also be reversed. Additionally, a tank for temporarily storing the treated water from the primary pure water production apparatus 1 can be provided upstream of the secondary pure water production apparatus 2.

[0076] In the second ultraviolet oxidation device 21, organic matter is oxidized and decomposed. In the hydrogen peroxide removal device 22, hydrogen peroxide generated in the preceding second ultraviolet oxidation device 21 is decomposed. In the degassing device 23, dissolved oxygen and other gases in the water are removed. In the ion exchange device 24, impurity ions in the water are removed. In the ultrafiltration membrane device 25, particles generated from ion exchange resins and the like are removed.

[0077] After the hydrogen peroxide removal device 22, any of the above-mentioned devices may be omitted as needed, but it is preferable to provide at least one of a degassing device (e.g., a membrane degassing device) 23 and an ion exchange device 24 (e.g., a non-regenerative ion exchange device) to perform at least one of degassing treatment and ion exchange treatment on the treated water using the hydrogen peroxide removal device.

[0078] (Hydrogen peroxide removal unit (catalyst unit)) The hydrogen peroxide removal unit installed in the secondary pure water production plant is a catalyst device used to decompose hydrogen peroxide generated in the upstream ultraviolet oxidation unit, and includes an ion exchanger (catalyst support) supported on a platinum group metal catalyst.

[0079] Examples of platinum group metal catalysts include ruthenium, rhodium, palladium, osmium, iridium, and platinum. One or more of these metals can be used alone, in combination, or in alloys of two or more. Among these catalyst metals, platinum, palladium, and platinum-palladium alloys are preferred, and they can be used alone or in combination. Palladium is particularly preferred due to its excellent catalyst activity and relatively low cost.

[0080] Examples of supports for platinum group metal catalysts include metal oxides such as magnesium oxide, titanium dioxide, alumina, silica-alumina, and zirconium oxide, activated carbon, zeolite, diatomaceous earth, and ion exchangers (ion exchange resins, monolithic organic porous anion exchangers, etc.), among which ion exchangers are preferred. Ion exchange resins are preferred as ion exchangers, and in embodiments of the present invention, the ion exchanger supporting the platinum group metal catalyst is preferably an ion exchange resin supporting the platinum group metal catalyst (hereinafter appropriately referred to as "catalyst resin"). Anion exchangers are preferred as ion exchangers, and anion exchange resins are preferred, with strongly basic anion exchange resins being particularly preferred. The shape of the support for the platinum group metal catalyst is not particularly limited; granular and particulate forms can be used. When using anion exchange resins such as anion exchange resins as supports for the platinum group metal catalyst, gel-like resins (gel-type resins) can be used.

[0081] By contacting the water to be treated, which contains hydrogen peroxide, with such a catalyst support, the hydrogen peroxide in the water is decomposed through the reaction 2H2O2→2H2O+O2.

[0082] As an ion exchanger (catalyst support) for such a platinum group metal catalyst, the catalyst resin disclosed in Japanese Patent Application Publication No. 2010-069460 is preferred, for example.

[0083] Specifically, it is preferable to use a strong basic anion exchange resin supported on a platinum group metal catalyst, wherein 70% or more, preferably 90% or more, and more preferably 95% or more of the total exchange capacity of the strong basic anion exchange resin is of the OH type.

[0084] The loading of platinum group metal catalysts (catalyst metals) on this strongly basic anion exchange resin is in the range of 10 mg-catalyst / LR to 500 mg-catalyst / LR, preferably 10 mg-catalyst / LR to 170 mg-catalyst / LR, and more preferably 10 mg-catalyst / LR to 50 mg-catalyst / LR. It should be noted that R is an abbreviation for OH-type standard anion exchange resin, and "mg-catalyst / LR" refers to the mass (mg) of catalyst in 1 L of OH-type standard anion exchange resin.

[0085] From the perspective of hydrogen peroxide decomposition efficiency, the above-mentioned strongly basic anion exchange resin is preferably in gel form.

[0086] Alternatively, the catalyst resin described above can be obtained by passing a solution of platinum group metal ions into the strongly basic anion exchange resin, followed by the introduction of a reducing agent such as formalin, thereby loading the platinum group metal catalyst (catalyst metal) onto the strongly basic anion exchange resin.

[0087] Preferably, the water to be treated is supplied at a flow velocity SV30–2000hr. -1 The catalyst resin is in contact with a range of SV200-2000hr. -1 The range of contact between the catalyst and the resin.

[0088] Alternatively, a hydrogen supply device can be installed in the hydrogen peroxide removal unit to supply hydrogen to the water being treated. This facilitates the decomposition of hydrogen peroxide in the water and makes it easier to remove gaseous components such as oxygen produced by the decomposition of hydrogen peroxide through degassing.

[0089] (Ultraviolet oxidation device) The first and second ultraviolet oxidation devices used in this invention can be ultraviolet oxidation devices commonly used in ultrapure water manufacturing equipment.

[0090] There are no particular limitations on ultraviolet oxidation devices as long as they have ultraviolet lamps capable of irradiating the water to be treated with ultraviolet light of a wavelength of at least 100 to 200 nm and capable of oxidizing and decomposing organic matter in the water to be treated.

[0091] From the viewpoint of decomposing organic matter in the treated water, the ultraviolet oxidation device is preferably equipped with an ultraviolet lamp capable of irradiating ultraviolet light with a wavelength around 185 nm. There are no particular limitations on the ultraviolet lamp, but a low-pressure mercury lamp is preferred. Furthermore, ultraviolet oxidation devices are available in flow-through and immersion types; from the viewpoint of treatment efficiency, the flow-through type is preferred.

[0092] The first and second ultraviolet oxidation devices are capable of measuring a first TOC value (TOC) as described above. SUP ) and the second TOC value (TOC TRE It consists of a method to control (or be able to operate) the amount of ultraviolet radiation.

[0093] The ultrapure water production apparatus according to embodiments of the present invention may include an ultraviolet irradiation control device attached to a second ultraviolet oxidation device, which is configured to control (or operate) the ultraviolet irradiation of the second ultraviolet oxidation device based on an input TOC value. Specifically, the ultraviolet irradiation control device is configured to input a first TOC value (TOC... SUP ) and the second TOC value (TOC TREIt can control (or operate) the amount of ultraviolet radiation from the second ultraviolet oxidation device so that its difference ΔTOC (TOC) SUP -TOC TRE The ultraviolet irradiation control device can be configured to reduce the ultraviolet irradiation to 1 ppb or less. It can also be configured to further control (or operate) the ultraviolet irradiation of the first ultraviolet oxidation device.

[0094] First TOC value (TOC SUP When the UV radiation intensity of the second UV oxidation device is increased, if the goal is to reduce the TOC of the ultrapure water obtained from the ultrapure water production unit by simply increasing the UV radiation intensity of the second UV oxidation device, the ΔTOC may sometimes exceed 1 ppb. Therefore, it is necessary to control (or operate) the UV radiation intensity of the second UV oxidation device to maintain the ΔTOC below 1 ppb. In this case, the UV radiation intensity of the second UV oxidation device can be controlled (or operated), and the UV radiation intensity of the first UV oxidation device can be increased to reduce the first TOC value (TOC). SUP ).

[0095] The aforementioned ultraviolet irradiation control device can control (or operate) the ultraviolet irradiation of the first ultraviolet oxidation device to achieve a first TOC value (TOC). SUP The first ultraviolet oxidation device can be configured such that the input TOC value is below a specified value (e.g., below 5 ppb). Alternatively, a separate ultraviolet irradiation control device can be provided with the first ultraviolet oxidation device, which can control (or operate) the ultraviolet irradiation of the first ultraviolet oxidation device to achieve the input first TOC value (TOC). SUP The configuration is such that the value is below a specified value (e.g., below 5 ppb). Based on these configurations, the first TOC value (TOC...) is... SUP When the value of the first TOC increases to exceed a specified value (e.g., 5 ppb), the first TOC value can be increased by increasing the amount of ultraviolet radiation from the first ultraviolet oxidation device. SUP Control (or operate) in a manner that is below a specified value (e.g., below 5 ppb).

[0096] In addition, the aforementioned ultraviolet irradiation control device can also control (or operate) the ultraviolet irradiation of the first and / or second ultraviolet oxidation devices to achieve a second TOC value (TOC). TRE It is configured such that the value is below a specified value (e.g., below 1 ppb). Based on this configuration, the second TOC value (TOC...) is... TRE When the value increases to exceed a specified value (e.g., 1 ppb), the second TOC value (TOC) can be increased by increasing the UV irradiation of the first UV oxidation device and / or the second UV oxidation device. TREThe UV irradiation of the second UV oxidation device is controlled (or operated) to be below a specified value (e.g., below 1 ppb). However, the UV irradiation of the second UV oxidation device is controlled (or operated) as described above, so that ΔTOC is maintained below 1 ppb.

[0097] Methods for controlling the ultraviolet irradiation amount of an ultraviolet oxidation apparatus using an ultraviolet irradiation amount control device include, for example, methods for controlling the number of multiple ultraviolet lamps in the ultraviolet oxidation apparatus that are lit, methods for controlling the lighting position of the multiple ultraviolet lamps in the ultraviolet oxidation apparatus (which position of the multiple ultraviolet lamps is lit or turned off), and methods for controlling the current value supplied to the multiple ultraviolet lamps in the ultraviolet oxidation apparatus. Besides these methods, known methods related to the control of ultraviolet irradiation amount may also be appropriately employed.

[0098] Most of the OH radicals generated by water decomposition under ultraviolet (UV) irradiation in the UV oxidation unit are used for the decomposition of organic matter, but the remaining OH radicals bond with each other to form hydrogen peroxide. This hydrogen peroxide is decomposed and removed in a subsequent hydrogen peroxide removal unit (catalyst unit). On the other hand, the organic matter (TOC) in the treated water is oxidized and decomposed into organic acids by the UV oxidation unit, and further oxidized and decomposed into CO2, forming carbonic acid in the water. As a result, the treated water contains inorganic carbonate ions. These inorganic carbonate ions pose a problem of degrading the catalyst support in the hydrogen peroxide removal unit.

[0099] According to an embodiment of the present invention, by controlling or operating the ultraviolet irradiation amount of the first and second ultraviolet oxidation devices, the TOC value of the supply water supplied to the second ultraviolet oxidation device is adjusted to [amount missing]. SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation unit (TOC) TRE The difference ΔTOC(TOC) SUP -TOC TRE The concentration is below 1 ppb, which ensures that the amount of TOC components oxidized and decomposed by the second ultraviolet oxidation unit is below a specified amount. Therefore, the concentration of inorganic carbonate ions in the effluent from the second ultraviolet oxidation unit can be suppressed to below a specified amount, thus preventing the degradation of the catalyst support in the subsequent hydrogen peroxide removal unit caused by inorganic carbonate ions, and enabling a stable supply of ultrapure water with high purity (operating in a manner that minimizes water quality fluctuations).

[0100] (Membrane degassing device) A membrane degassing device is an apparatus in which treated water from a hydrogen peroxide removal unit flows into one chamber separated by a gas separation membrane, and the pressure in the other chamber is reduced, thereby causing the gas contained in the treated water to be transferred to the other chamber through the gas separation membrane and removed. For example, a gas separation membrane formed from a hydrophobic polymer membrane such as a tetrafluoroethylene-based or polyolefin-based membrane can be used, in the form of a hollow fiber membrane.

[0101] As a device for removing gases contained in treated water from a hydrogen peroxide removal unit, other degassing devices can be used, such as vacuum degassing devices or heated degassing devices. However, when using such other degassing devices, it is possible for impurities to be introduced into the water from these devices, or for impurities to dissolve into the water from the packing material of the device. In contrast, membrane degassing devices do not cause such problems of impurities being introduced into or dissolved into the water, and are therefore particularly preferred as degassing devices.

[0102] (Non-regenerative ion exchange device) As a non-regenerative ion exchange device (tube polisher), there are no particular limitations as long as it is a device that removes impurities such as cations and anions from the treated water from the hydrogen peroxide removal device. Examples include: ion exchange devices using a mixed bed of strong acid cation exchange resin and strong base anion exchange resin (mixed bed 1-tower type); ion exchange devices using a single bed of strong base anion exchange resin (single bed 1-tower type); multi-layer ion exchange devices with a single bed of strong base anion exchange resin on the inlet side and a mixed bed of strong acid cation exchange resin and strong base anion exchange resin on the outlet side (multi-layer 1-tower type); and ion exchange devices with a single bed of strong base anion exchange resin on the front side and a mixed bed of strong acid cation exchange resin and strong base anion exchange resin on the back side (2-tower type), etc. Among these considerations, considering that the pH of the water treated at any location within the device changes minimally and that ion exchange can be carried out efficiently, a mixed-bed 1-tower ion exchange device is preferred.

[0103] The ultrapure water manufacturing apparatus and method according to the embodiments of the present invention described above can provide an ultrapure water manufacturing apparatus and method that can suppress the deterioration of the catalyst support in the downstream catalyst device, and remove hydrogen peroxide generated in the ultraviolet oxidation device, thereby providing a long-term stable supply of ultrapure water with good water quality.

[0104] The ultrapure water manufacturing apparatus and method described in the embodiments of the present invention can supply high-purity ultrapure water that has removed impurities such as organic matter, hydrogen peroxide, dissolved gases, ionic substances and particles. Such ultrapure water is suitable for cleaning electronic components and manufacturing equipment for electronic components.

[0105] Example <Confirmation Test on the Correlation between the OH Form Ratio of Catalyst Resin and Hydrogen Peroxide Removal Performance> As in Test Example 1 below, a test was conducted in which treated water containing hydrogen peroxide was passed through a catalyst unit (hydrogen peroxide removal unit), and the results of this test confirmed the correlation between the OH form ratio of the catalyst resin and the hydrogen peroxide removal performance.

[0106] (Experimental Example 1) As a container for filling the catalyst resin, prepare as follows Figure 3 The diagram shows an ion exchange resin container (column) 30 with an inner diameter of 31 mm and a height of 1 m, equipped with a screen 32 on its bottom surface. The screen 32 is configured to cover the outlet of the treated water on the bottom surface of the container 30, serving as a filter to prevent the catalyst resin filled inside the container from flowing out while allowing water to pass through. Next, catalyst resin 31 is filled to a height of 10 cm. The container filled with catalyst resin 31 was then tested as a catalyst device (hydrogen peroxide removal device).

[0107] As the catalyst resin 31 filled in container 30, a resin consisting of CO3-type catalyst resin and OH-type catalyst resin layered in different mass ratios (CO3 / OH = 30 / 70, 50 / 50, 70 / 30, 90 / 10), and a single layer of CO3-type catalyst resin (CO3 / OH = 100 / 0) are prepared. The OH-type catalyst resin is a Pd-loaded strong base anion exchange resin (product name: ORLITE (registered trademark) HR43-HG) manufactured by Organo Corporation. The CO3-type catalyst resin is a carbonated (CO3-type) catalyst resin prepared by passing carbonated water through the above-mentioned OH-type catalyst resin. When the resistivity values ​​at the inlet and outlet are the same during water flow, it is determined that it has completely become carbonated (CO3-type). These catalyst resins are filled into container (column) 30 as described above to prepare a catalyst device.

[0108] Next, prepare H2O2 with a concentration of 35 ppb ( μ The treated water (g / L) was fed to the catalyst unit (the treated water was supplied from the top of container 30, and the treated water flowed out from the bottom of container 30) at a flow rate of LV425. The H2O2 concentration of the outflow water (treated water) was determined by phenolphthalein colorimetric analysis one hour after the start of the water flow. The results of Experimental Example 1 are shown below. Figure 2 (The curve represents the result of Experiment 1).

[0109] Figure 2 This indicates the correlation between the OH form ratio of the ion exchange resin after water flow and its hydrogen peroxide removal performance. Figure 2 The vertical axis represents the H2O2 concentration in the treated water. μ The horizontal axis (lower horizontal axis) represents the OH form ratio of the catalyst resin (Pd(OH) ratio (%)), and the upper horizontal axis represents the CO3 form ratio of the catalyst resin (Pd(CO3) ratio (%)).

[0110] like Figure 2 As shown, the lower the proportion of OH type (Pd(OH) ratio) (i.e., the higher the proportion of CO3 type), the higher the concentration of H2O2 in the treated water and the lower the hydrogen peroxide removal performance.

[0111] <Confirmation Test on Catalyst Resin Deterioration Caused by Inorganic Carbonate Ions and UV Irradiation Conditions (ΔTOC below 1 ppb)> As in Test Example 2 below, a test was conducted in which treated water containing hydrogen peroxide and carbonic acid (inorganic carbonate ions) was passed through the catalyst unit (hydrogen peroxide removal unit) to confirm the deterioration of the catalyst resin.

[0112] Furthermore, the results of this experiment confirm that if the amount of TOC decomposition (equivalent to ΔTOC) in the upstream ultraviolet oxidation unit (second ultraviolet oxidation unit) of the catalyst unit is less than 1 ppb, the degradation of the catalyst resin in the downstream catalyst unit can be sufficiently suppressed.

[0113] (Experimental Example 2) For the above-mentioned test example 1, a further scaled-up real machine was used for the test.

[0114] In a 320mm inner diameter FRP (Fiberglass Reinforced Plastics) tank, non-regenerated ion exchange resin is filled sequentially to a height of 80cm, followed by catalyst resin to a height of 10cm. A filter is installed at the bottom of the tank to prevent overflow of the filled ion exchange resin while allowing water to pass through. The non-regenerated ion exchange resin used is refined ion exchange resin (product name: ESP-2) manufactured by Organo Corporation, and the catalyst resin used is a Pd-loaded strong base anion exchange resin (product name: ORLITE (registered trademark) HR43-HG) manufactured by Organo Corporation.

[0115] Water to be treated is supplied from the top of the tank, flowing through the catalyst resin and non-regenerating ion exchange resin in that order, causing the treated water to flow out from the bottom of the tank. The carbonic acid concentration of the treated water (supply water) is 5 ppb. μ g / L), H2O2 concentration was 35 ppb ( μ g / L), flow rate is 3.4m³. 3 / h.

[0116] The H2O2 concentration of the effluent (treated water) from the tank was periodically determined using phenolphthalein colorimetric analysis. Furthermore, regarding the catalyst resin at the time of this determination, the proportion of OH-form compounds (Pd(OH)2) in the catalyst resin was calculated based on the carbonic acid concentration and flow rate of the treated water (supply water), the exchange capacity of the catalyst resin, etc. It should be noted that, to confirm whether there is any deviation between the calculated and measured values, the proportion of OH-form compounds in the catalyst resin was measured at a single point to confirm that there is no deviation. The determination of the proportion of OH-form compounds in the catalyst resin was performed by titration. In this titration method, sodium nitrate solution, hydrochloric acid, and ammonia were respectively introduced into each collected and divided sample resin, and the OH-form and CO32- forms were measured respectively. 2- Type, Cl - The ion exchange capacity of each ion type is calculated, and the ratio (%) of the ion exchange capacity of each ion type to the total ion exchange capacity (total ion exchange capacity) is determined. Based on the obtained value, the OH type ratio of the sample resin is calculated.

[0117] The results of Experiment Example 2 are shown below. Figure 2 (The broken line represents the results of test example 2).

[0118] Figure 2 This indicates the relationship between the proportion of OH-type catalyst resin (Pd(OH) ratio) and the H2O2 concentration in the treated water after water flow. Figure 2 The vertical axis represents the H2O2 concentration in the treated water. μ The horizontal axis below the catalyst resin represents the proportion of OH type (Pd(OH) proportion (%)), and the horizontal axis above the catalyst resin represents the proportion of resin after the OH of the catalyst resin is replaced by inorganic carbonate ions (CO3 type proportion: Pd(CO3) proportion (%)).

[0119] like Figure 2 As shown, it can be seen that as the proportion of OH-type catalyst resin (Pd(OH) proportion (%)) decreases (Pd(CO3) proportion increases), that is, as the degradation of catalyst resin intensifies, the concentration of H2O2 in the treated water increases.

[0120] Additionally, until the carbonic acid concentration reaches 5 ppb ( μ Up to 8 months after the treated water was circulated, the H2O2 concentration was 1 ppb (g / L). μ When the concentration of Pd(OH) is below g / L, the proportion of Pd(OH) at that moment is 60%.

[0121] Therefore, if the carbonic acid concentration of the treated water is below 5 ppb, the H2O2 concentration can be reduced sufficiently over a long period of time, which means that the degradation of the catalyst resin can be effectively inhibited.

[0122] Here, as mentioned above, the ratio of TOC value to inorganic carbonate ion concentration (TOC value: inorganic carbonate ion concentration) is 1:5. Therefore, a carbonic acid concentration of 5 ppb (equivalent to the maximum concentration of dissociated inorganic carbonate ions) is equivalent to a TOC value of 1 ppb. Thus, if the amount of TOC decomposition in the upstream UV oxidation unit of the catalyst unit (equivalent to ΔTOC) is less than 1 ppb, it can be said that the degradation of the downstream catalyst unit can be sufficiently suppressed.

[0123] Explanation of reference numerals in the attached figures 1. Primary pure water production device 2. Secondary pure water production unit 11 First Ultraviolet Oxidation Unit 12 Ion exchange devices 13. Boron-selective resin device 14 Degassing device 21 Second Ultraviolet Oxidation Device 22. Hydrogen peroxide removal unit (catalyst unit) 23 Degassing device 24 Ion exchange device 25 Ultrafiltration Membrane Device 30 Ion exchange resin containers (columns) 31 Catalyst Resin 32 sieves.

Claims

1. An ultrapure water production apparatus, characterized in that, It is equipped with a primary pure water production unit and a secondary pure water production unit. The primary pure water production device includes a first ultraviolet oxidation device. The secondary pure water production device includes a second ultraviolet oxidation device and a hydrogen peroxide removal device located downstream of the second ultraviolet oxidation device. The hydrogen peroxide removal device includes an ion exchanger supported on a platinum group metal catalyst. The amount of ultraviolet radiation from the second ultraviolet oxidation device is controlled to ensure that the TOC value of the water supplied to the second ultraviolet oxidation device is [i.e., TOC]. SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation device is... TRE The difference ΔTOC is TOC SUP -TOC TRE It is below 1 ppb.

2. The ultrapure water manufacturing apparatus according to claim 1, wherein, The amount of ultraviolet radiation from the first ultraviolet oxidation device is controlled to ensure that the TOC value of the supply water to the second ultraviolet oxidation device is [i.e., TOC]. SUP Satisfy 0 <TOC SUP ≤5ppb.

3. The ultrapure water manufacturing apparatus according to claim 1, wherein, The ultraviolet irradiation dose of the first ultraviolet oxidation device is greater than that of the second ultraviolet oxidation device.

4. The ultrapure water manufacturing apparatus according to claim 1, wherein, The ultraviolet irradiation levels of the first and second ultraviolet oxidation devices are controlled to ensure that the TOC value of the treated water after treatment by the second ultraviolet oxidation device is [i.e., TOC]. TRE It is below 1 ppb.

5. The ultrapure water manufacturing apparatus according to claim 1, wherein, The ultrapure water manufacturing apparatus has a water quality meter installed before and / or after the second ultraviolet oxidation apparatus.

6. The ultrapure water manufacturing apparatus according to claim 1, wherein, The ultrapure water manufacturing apparatus includes: a first TOC meter installed before the second ultraviolet oxidation device; and a second TOC meter installed after the second ultraviolet oxidation device.

7. A method for producing ultrapure water, characterized in that, Use an ultrapure water production unit that includes a primary pure water production unit and a secondary pure water production unit. The primary pure water production device includes a first ultraviolet oxidation device. The secondary pure water production device includes a second ultraviolet oxidation device and a hydrogen peroxide removal device located downstream of the second ultraviolet oxidation device. The hydrogen peroxide removal device includes an ion exchanger supported on a platinum group metal catalyst. The amount of ultraviolet radiation used to operate the second ultraviolet oxidation device is adjusted to achieve a TOC value (i.e., TOC) in the supply water. SUP The TOC value of the treated water after treatment by the second ultraviolet oxidation device is... TRE The difference ΔTOC is TOC SUP -TOC TRE It is below 1 ppb.

8. The method for producing ultrapure water according to claim 7, wherein, The amount of ultraviolet radiation irradiated by the first ultraviolet oxidation device is adjusted to achieve a TOC value (i.e., TOC) in the supply water to the second ultraviolet oxidation device. SUP Satisfy 0 <TOC SUP ≤5ppb.

9. The method for producing ultrapure water according to claim 7, wherein, The operation is carried out in such a way that the ultraviolet irradiation dose of the first ultraviolet oxidation device is greater than that of the second ultraviolet oxidation device.

10. The method for producing ultrapure water according to claim 7, wherein, in, The ultrapure water manufacturing apparatus includes: a first TOC meter installed before the second ultraviolet oxidation device; and a second TOC meter installed after the second ultraviolet oxidation device.

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