WO2019116653A1

WO2019116653A1 - Method and apparatus for removing hydrogen peroxide

Info

Publication number: WO2019116653A1
Application number: PCT/JP2018/033813
Authority: WO
Inventors: 森田　博志; 康晴港
Original assignee: 栗田工業株式会社
Priority date: 2016-12-28
Filing date: 2018-09-12
Publication date: 2019-06-20
Also published as: JP6451824B2; KR20200096485A; KR102340160B1; JP2018108577A; TW201823166A; WO2018123156A1; CN111183118B; TW201930200A; TWI820042B; CN111183118A

Abstract

A method and an apparatus both for decomposing and removing hydrogen peroxide by flowing water containing hydrogen peroxide through columns 21 to 25 each filled with a platinum-based catalyst, wherein the hydrogen peroxide removal performance can be recovered by halting the flowing of the water through one or some of the columns at a predetermined point of time and storing the platinum-based catalyst in the columns in ultra-pure water. It is possible to flow a nitrogen gas or hydrogen-dissolved water through the columns through which the flowing of the water is halted at the predetermined point of time, and it is also possible to increase the volume of the water to be flowed through the other columns.

Description

Method and apparatus for hydrogen peroxide removal

The present invention relates to a method and apparatus for removing hydrogen peroxide in water in a pure water production process. In the present invention, pure water includes ultrapure water.

Ultra pure water for cleaning semiconductor and electronic materials is raw water (industrial water, municipal water, etc.) in the ultra pure water production facility consisting of a pretreatment unit, a primary pure water production unit, and a secondary pure water production unit (subsystem). Well water etc.) is manufactured.

In a pretreatment device including an aggregation, pressurized floatation (precipitation), filtration (membrane filtration) device and the like, suspended substances and colloidal substances in raw water are removed. In addition, in this process, removal of high molecular weight organic substances, hydrophobic organic substances and the like is also possible.

In a primary pure water production apparatus equipped with a reverse osmosis membrane separation device, a degassing device, and an ion exchange device (mixed bed type or 4 bed 5 tower type, etc.), ions and organic components in raw water are removed. In the reverse osmosis membrane separation apparatus, salts are removed, and ionic and colloidal TOC are removed. In the ion exchange apparatus, salts are removed and TOC components adsorbed or ion exchanged by the ion exchange resin are removed. The deaerator removes inorganic carbon (IC) and dissolved oxygen.

The primary pure water from the primary pure water production apparatus is processed in an ultraviolet (UV) irradiation apparatus, an ion exchange apparatus and an ultrafiltration (UF) membrane separation apparatus in a subsystem to produce ultrapure water. In the UV oxidizer, the 185 nm UV irradiated from the UV lamp decomposes the TOC into an organic acid and further CO ₂ . The organic matter and CO ₂ generated by the decomposition are removed by an ion exchange device (usually, a mixed bed ion exchange device) in the latter stage. In the UF membrane separation apparatus, fine particles are removed, and fragments and the like of the ion exchange resin flowing out of the ion exchange apparatus are also removed. The ultrapure water thus obtained is supplied to the use point.

The organic substance (TOC component) in water decomposes | disassembles and the organic acid and carbonic acid are produced | generated by the oxidation process by the ultraviolet irradiation in a ultraviolet-ray oxidation apparatus. The oxidative decomposition mechanism of the TOC component in this ultraviolet oxidation apparatus oxidizes and decomposes water to generate OH radicals and oxidizes and decomposes the TOC component by this OH radical, and the ultraviolet irradiation dose sufficiently oxidizes the TOC in water It is considered to be over-irradiated so that it can be decomposed.

As described above, when the ultraviolet irradiation amount is large, the OH radicals generated by the decomposition of water become excessive, and thus the excess OH radicals associate to generate hydrogen peroxide. The generated hydrogen peroxide is decomposed when coming into contact with the anion exchange resin of the mixed bed ion exchange apparatus in the latter stage, but at that time, the ion exchange resin is deteriorated. Dissolved oxygen also increases with this decomposition. Further, the decomposition of the ion exchange resin newly generates a TOC component derived from the ion exchange resin, and the water quality of the ultrapure water obtained is lowered. Further, hydrogen peroxide remaining even after passing through the mixed bed ion exchange apparatus degrades the degassing apparatus and the UF membrane in the latter stage of the mixed bed ion exchange apparatus.

Patent Document 1 discloses, as a method for removing hydrogen peroxide in ultrapure water, water to be treated containing hydrogen peroxide discharged from an ultraviolet oxidation treatment apparatus of an ultrapure water production apparatus, metal nanocolloid particles of platinum group. There is described a method of decomposing hydrogen peroxide in treated water to 1 ppb or less by contacting with a hydrogen peroxide decomposition catalyst supported on an anion exchange resin carrier.

Patent Document 2 describes a method for producing pure water, in which water to be treated is subjected to ultraviolet oxidation treatment with an ultraviolet oxidation device to suppress deterioration of the platinum catalyst, and then hydrogen peroxide removal treatment is carried out using the platinum catalyst. It is described that the TOC of the water supply to the ultraviolet oxidation apparatus is 5 ppb or less.

JP 2007-185587 A JP, 2015-93226, A

As described above, platinum group catalysts represented by Pt are conventionally utilized in the decomposition of oxidizing substances and the like. In the ultrapure water production system, the removal of hydrogen peroxide generated as a by-product in the ultraviolet oxidation process for the purpose of decomposing a small amount of organic substance contained in water has been a problem in recent years, and Pt nanocolloid was supported. A hydrogen peroxide decomposition process is performed using an ion exchange resin, a Pd-loaded resin, or the like.

Although this hydrogen peroxide decomposition treatment can reduce the concentration of hydrogen peroxide in the water to below the target concentration (for example, 1 ppb), the performance of the catalyst decreases with long-term use.

An object of the present invention is to provide a hydrogen peroxide removal method and apparatus capable of suppressing or recovering the performance deterioration of a platinum-based catalyst and maintaining a state with sufficient catalytic activity for a long time.

In general, lowering the organic substance concentration in the water to be treated flowing into the platinum-based catalyst device suppresses the performance deterioration of the platinum-based catalyst. The present inventors have intensively studied to further suppress the performance deterioration. As a result, it has been found that the performance deterioration of the platinum-based catalyst is also due to the oxidation of the catalyst surface, and by suppressing the oxidation of the catalyst surface, the performance deterioration of the platinum-based catalyst is suppressed.

The present invention has been made based on such findings.

The hydrogen peroxide removal method of the present invention is a hydrogen peroxide removal method of removing hydrogen peroxide by passing hydrogen peroxide-containing water through a hydrogen peroxide removal device having a platinum-based catalyst loading vessel installed in parallel, Hydrogen peroxide removal performance recovery operation of stopping the water supply of hydrogen peroxide-containing water to a part of the platinum-based catalyst filled container and storing the platinum-based catalyst filled in the container in ultrapure water for a predetermined period It is characterized by doing.

In one aspect of the present invention, the hydrogen peroxide removal performance recovery operation replaces the water in the container in which the water flow is stopped with ultrapure water, and the platinum-based catalyst is predetermined in the ultrapure water in the container. It is an operation to save for a period.

In one aspect of the present invention, in the hydrogen peroxide removal performance recovery operation, the platinum-based catalyst in the container is removed from the container in which the water flow is stopped, and the removed platinum-based catalyst is stored in ultrapure water for a predetermined period After that, it is an operation to refill the container.

In one aspect of the present invention, a non-oxidizing gas such as nitrogen gas is supplied to the ultrapure water.

In one aspect of the present invention, the ultrapure water is ultrapure water in which hydrogen is dissolved.

In one aspect of the present invention, the hydrogen peroxide removing device is installed in an ultrapure water producing device, and increases the amount of water flowing to the platinum-based catalyst filled container other than the part during the predetermined time.

The hydrogen peroxide removing device of the present invention comprises a platinum-based catalyst filled container installed in parallel, hydrogen peroxide containing water passing means for passing hydrogen peroxide containing water to each container, and non-oxidizing property for each container. A supply means for supplying gas or hydrogen-dissolved water, and a switching means for switching between hydrogen peroxide-containing water passage to each container and non-oxidative gas or hydrogen-dissolved water supply.

The catalyst itself has the function of reducing the barrier to any chemical reaction without any change and promoting the progress. Prolonged exposure to oxidizing conditions can result in oxidation of the surface of the catalyst, which can lead to reduced performance of the catalyst.

The platinum-based catalyst becomes an irreversible oxide when the oxidation proceeds strongly, but in the reversible surface oxidation stage, the performance is restored by releasing from the continuous oxidation state. The present inventors have found that the platinum-based catalyst is released from the continuous oxidation state and the performance of the catalyst is recovered by stopping the water flow and immersing and storing the platinum-based catalyst in ultrapure water. The The hydrogen peroxide decomposition performance can be recovered in a shorter period of time by bubbling N ₂ gas into ultrapure water or passing ultrapure water having hydrogen dissolved therein during this water stopping period.

The deterioration of the catalyst is caused not only by the surface oxidation of the platinum group catalyst but also by contamination with impurities such as organic substances contained in the water to be treated. In addition, there is also deterioration of the carrier (for example, ion exchange resin) itself which is a base material. For this reason, in the case where the amount of impurities in the water to be treated is small and the hydrogen peroxide concentration is relatively high, oxidation is the main cause of performance deterioration, and the present invention is particularly effective.

According to the present invention, the lifetime of the platinum-based catalyst can be extended without replacing the platinum-based catalyst with a new one.

A plurality of platinum-based catalyst filled containers are installed in parallel, and while performance recovery processing is applied to some of the containers, water flow switching operation to another container is repeatedly repeated in order to set the water flow rate to another container. The hydrogen peroxide decomposition treatment can be performed for a long time while maintaining the desired treated water quality and amount of water.

It is explanatory drawing of this invention method. It is explanatory drawing of an example of this invention apparatus. It is a system diagram of an ultrapure water production system.

Hereinafter, the present invention will be described in more detail.

The hydrogen peroxide removal method and apparatus of the present invention are suitable for use in the ultrapure water production process. In the ultrapure water production process, as described above, primary pure water from the primary pure water production apparatus is processed by the subsystem to produce ultrapure water. In the subsystem, primary pure water is treated by an ultraviolet oxidizer, hydrogen peroxide is removed by a hydrogen peroxide remover having a platinum-based catalyst, and then a non-regenerating ion exchange unit, a membrane deaerator, a UF membrane unit Water flow

The ultraviolet oxidation treatment in the ultraviolet oxidation apparatus oxidizes and decomposes the TOC component to form an organic acid and carbonic acid, as well as hydrogen peroxide. In the present invention, the effluent water from the ultraviolet oxidation apparatus is passed through the hydrogen peroxide removing apparatus to remove hydrogen peroxide. As this hydrogen peroxide removal device, a container filled with a platinum-based catalyst is employed. The platinum-based catalyst is preferably a platinum-based metal colloidal particle, particularly a nanocolloidal particle supported on a carrier.

As platinum-based metals, ruthenium, rhodium, palladium, osmium, iridium and platinum can be mentioned. These platinum group metals can be used alone or in combination of two or more, or as an alloy of two or more, or the purity of a naturally produced mixture. It can also be used without separating the product into single components. Among these, platinum, palladium, platinum / palladium alloy alone or a mixture of two or more of them can be particularly preferably used because they have strong catalytic activity.

There is no restriction | limiting in particular in the method to manufacture the nanocolloid particle | grains of a platinum-type metal, For example, a metal salt reduction reaction method, a combustion method, etc. can be mentioned. Among them, the metal salt reduction reaction method can be suitably used because it is easy to produce and metal nanocolloid particles of stable quality can be obtained.

The average particle size of the platinum-based metal nanocolloid particles is preferably 1 to 50 nm, more preferably 1.2 to 20 nm, and still more preferably 1.4 to 5 nm. This particle size is a value obtained from electron microscope imaging.

Examples of the support on which the platinum-based metal nanocolloid particles are supported include magnesia, titania, alumina, silica-alumina, zirconia, activated carbon, zeolite, diatomaceous earth, ion exchange resin, and the like. Among these, anion exchange resins can be particularly preferably used. Since the platinum-based metal nanocolloid particles have an electric double layer and are negatively charged, they are stably supported by the anion exchange resin and hardly peel off. Platinum-based metal nanocolloidal particles supported on an anion exchange resin show strong catalytic activity for hydrogen peroxide decomposition and removal. The exchange group of the anion exchange resin is preferably in the OH form. The OH type anion exchange resin makes the resin surface alkaline and promotes the decomposition of hydrogen peroxide.

The amount of platinum-based metal nanocolloid particles supported on the anion exchange resin is preferably 0.01 to 0.2% by weight, and more preferably 0.04 to 0.1% by weight.

Hydrogen peroxide in water is decomposed by the reaction of 2H ₂ O ₂ → 2H ₂ O + O ₂ by bringing hydrogen peroxide-containing water into contact with a hydrogen peroxide decomposition catalyst in which platinum-based metal nanocolloid particles are supported on a carrier. Be done.

The water flow rate of the hydrogen peroxide-containing water to the platinum-based catalyst filled container is preferably a space velocity SV of 100 to 2,000 h ⁻¹ , and more preferably 300 to 1,500 h ⁻¹ . Since the platinum-based catalyst has a very high decomposition rate of hydrogen peroxide, hydrogen peroxide is sufficiently decomposed even if SV is 100 h ⁻¹ or more. However, if the SV is more than 2,000 h ^-1 , the pressure loss of water passing through may be excessive, and the decomposition and removal of hydrogen peroxide may be insufficient.

A specific example of the hydrogen peroxide removal method and apparatus of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, a plurality of (five in the drawing) columns 21 to 25 packed with a platinum-based catalyst are arranged in parallel. The hydrogen peroxide-containing water such as the UV irradiation device outflow water is passed from the piping 1 to the columns 21 to 25 through the valves 11 to 15. Effluent water from the columns 21-25 is taken out via the valves 31-35 and the collecting pipe 2.

Treatment is performed in the same manner as parallel water flow through five columns 21-25. When signs of deterioration of treated water are recognized, water flow to one column (column 21 in FIG. 1 (b)) as shown in FIG. 1 (b), and

valves

11 and 31 are closed. The parallel operation is performed by temporarily stopping the flow rate of the remaining four columns 22 to 25 by 25% each to secure the treated water amount.

The following hydrogen peroxide removal performance recovery operation is performed for the column 21 whose water flow has been stopped.
(1) The water in the column 21 is replaced with ultrapure water, and the platinum catalyst in the column 21 is immersed and stored in the ultrapure water for a predetermined period in the column 21.
(2) The platinum-based catalyst in the column 21 is once taken out, immersed in ultrapure water in another container and stored for a predetermined period, and then the column 21 is refilled.
(3) In the above operation (1) or (2), a non-oxidizing gas such as N ₂ gas is supplied to the ultrapure water used for the immersion treatment of the platinum-based catalyst.
(4) In the above operation (1) or (2), ultrapure water in which hydrogen is dissolved is used as ultrapure water used for the immersion treatment of the platinum-based catalyst.
The operations (1) to (4) may be performed in combination of two or more.

The ultrapure water used for the immersion treatment of the platinum-based catalyst does not contain hydrogen peroxide and preferably has a hydrogen peroxide concentration of 2 μg / L, particularly less than 1 μg / L.

In the present invention, it is preferable to set the platinum-based catalyst in ultrapure water for a predetermined period of 1 day or more, particularly about 2 to 2 weeks.

In the present invention, in addition to the above operations (1) to (4), an operation in which the atmosphere in the column 21 is replaced with a nonoxidizing gas such as N ₂ gas, or hydrogen dissolved water is passed The operation may be performed.

After performing the above-mentioned hydrogen peroxide removal performance recovery operation, preferably water is passed through the column 21 experimentally and after confirming that the treated water quality is good, the

valves

11 and 31 are opened and the column 21 is opened. Resume water flow. Thereafter, the same performance recovery operation is sequentially performed on the other columns 22 to 25 to restore the performance to a good state.

After all five columns 21 to 25 have been recovered, they are returned to the five parallel water flows at the original standard flow rate.

In FIG. 2, three-way valves 41-45 are installed instead of valves 11-15, three-way valves 51-55 are installed instead of valves 31-35, and ultra pure water, N ₂ gas or hydrogen is installed in each column 21-25. A hydrogen peroxide removing device is shown which can supply dissolved water by switching the three-way valves 31 to 35, 51 to 55.

The pipes 61 to 65 branched from the pipe 60 are connected to the third ports of the three-way valves 41 to 45. The third ports of the three-way valves 51 to 55 are connected to the discharge pipe 70 via branch pipes 71 to 75. Ultra pure water, N ₂ gas or hydrogen-dissolved water is supplied from the pipe 60 to any of the columns 21 to 25, and the outflow gas or outflow water is discharged from the pipe 70.

As shown in FIGS. 1 and 2, if a standard SV of 400 / h passes water evenly through the columns 21 to 25 of the hydrogen peroxide removing apparatus provided with five columns 21 to 25 in parallel, 1 When the book enters the recovery process and four parallel water flows (for example, FIG. 1 (b)), the SV of each column increases to 500 / h. This is not desirable in terms of maintaining treated water quality. However, while the hydrogen peroxide decomposition life of platinum-based resin (without recovery treatment) is several years, the recovery treatment is about 1 week long per bottle, so an increase of 25% for each column It takes about four weeks for a long time. During this time, water flow to the columns whose performance has been restored one after another is resumed, so it is not difficult to maintain the treated water volume (SV 500 / h) as the whole hydrogen peroxide removing device.

In Fig. 1 and 2, five columns are installed in parallel, but six columns are installed in parallel, one of them is paused sequentially (performance recovery operation), and water is constantly supplied to five columns. You may drive it.

In this case, one container is stopped when a predetermined time (a predetermined hydrogen peroxide load) has passed, and one container which has not been used at the same time is started to flow water, so that each container has 5/6 of the total time It is a so-called merry-go-round operation in which intermittent operation for stopping water flow and 1/6 is sequentially performed, and operation with a margin can be performed.

According to the experimental results of the inventor, the following was recognized.
(1) When the water flow was resumed after stopping the water flow to the platinum-based catalyst filled container for a predetermined time, recovery of hydrogen peroxide decomposition performance was observed. The longer the outage, the higher the recovery.
(2) While stopping the flow of water to be treated into the platinum-based catalyst-filled container, an operation of removing O ₂ from the inside of the container by N ₂ gas ventilating was added, hydrogen peroxide in a shorter time than in (1) It was found that the degradation performance was restored.
(3) While stopping the flow of water to be treated into the platinum-based catalyst filled container, the water in the container is replaced with ultrapure water, and the platinum-based catalyst in the container is immersed and stored in the ultrapure water As a result, it was found that the hydrogen peroxide decomposition performance was recovered in a shorter time than in (1) and (2).
(4) The platinum-based catalyst is once withdrawn from the container during stopping of water flow to the platinum-based catalyst-filled container, immersed and stored in ultrapure water in another container for a predetermined time, and then refilled. After resuming, it was found that the hydrogen peroxide decomposition performance was recovered in a still shorter time than the above (1) to (3).
(5) After stopping the flow of water to be treated into the platinum-based catalyst filled container, when hydrogen-dissolved ultrapure water is passed, hydrogen peroxide decomposition performance is achieved in a shorter time than the above (1) to (4). Was found to recover.

The above embodiment is an example of the present invention, and the present invention may be an embodiment other than the above. For example, the number of columns is not limited to five.

[Reference Example 1]
What was shown in FIG. 3 was prepared as an ultrapure water manufacturing apparatus. The ultrapure water production system 81 is composed of three stages of a pretreatment system 82, a primary pure water production system 83, and a secondary pure water production system (subsystem) 84. In the pretreatment device 82 of the ultrapure water production device 81, the raw water W is filtered, coagulated and precipitated, and pretreatment with a precision filtration membrane is performed.

The primary pure water production system 83 includes a tank 85 for pretreatment water W1, a reverse osmosis (RO) membrane system 86, an ultraviolet (UV) oxidizer 87, and a regenerative ion exchange system (mixed bed type or four bed five towers) And the like) and a membrane degassing device 89.

The subsystem 84 includes a sub tank 91 for storing the primary pure water W2 manufactured by the primary pure water producing apparatus 83 and an ultraviolet oxidizer for processing the primary pure water W2 supplied from the sub tank 91 via a pump (not shown). 92, a platinum group metal catalyst resin tower 93, a membrane degassing device 94, a non-regenerating type mixed bed ion exchange device 95, and an ultrafiltration (UF) membrane 96 as a membrane filtration device There is. The fine particles are removed by the ultrafiltration (UF) membrane 96 to make ultrapure water W 3, which is supplied to the use point 97, and unused ultrapure water is returned to the sub tank 91.

Anion supporting platinum nanocolloidal particles having an average particle diameter of 3.5 nm on a strongly basic gel type anion exchange resin at a loading amount of 0.07% by weight, and supporting platinum group metal nanoparticles as a platinum group metal catalyst resin Exchange resin was prepared.

In the ultrapure water production system 81 of the apparatus configuration shown in FIG. 3, a platinum group metal catalyst resin tower 93 is configured using the above-described platinum group metal catalyst resin to produce ultrapure water W3. The hydrogen peroxide concentration (initial) of the inlet water and the outlet water of the metal catalyst resin tower 93 was measured. The results are shown in Table 1. Further, the hydrogen peroxide concentration (final stage) of the outlet water of the platinum group metal catalyst resin tower 93 after the operation of the ultrapure water production apparatus 81 was continued for a long period of time was measured. The results are shown in Table 1.

In addition, in order to measure hydrogen peroxide concentration, sodium sulfate (anhydrous) is added to 4.8 mg of phenolphthalein, 8 mg of copper sulfate (anhydrous) and 48 mg of sodium hydroxide to make 10 g, and for determination of trace hydrogen peroxide concentration The reagents were prepared. 0.5 g of the reagent was added to 10 mL of test water, dissolved, and allowed to stand at room temperature for 10 minutes, then the absorbance at 552 nm was measured, and the hydrogen peroxide concentration was calculated based on the measured value.

As apparent from Table 1, the increase in the hydrogen peroxide concentration of the ultrapure water W3 after a long period of operation is remarkable.

[Reference Example 2]
In Reference Example 1, the used resin of the platinum group metal catalyst resin tower 93 after being operated for a long time is taken out and packed in a column for test to obtain a platinum group metal catalyst resin tower for test. Further, for comparison, a new resin was similarly packed in a test column to make a platinum group metal catalyst resin tower.

300 μg / L or 1000 μg / L of hydrogen peroxide is added to ultrapure water (less than 1 μg / L of hydrogen peroxide) to prepare a test inlet water, and the test inlet water is passed through each test column described above. The hydrogen peroxide concentration of the outlet water after downward flow of water at a water velocity (SV) of 300 hr ^-1 was measured. The results are shown in Table 2.

As apparent from Table 2, the spent resin of the platinum group metal catalyst resin tower 93 after the long-term operation had a higher concentration of the outlet water hydrogen peroxide than the new resin. From this, it can be seen that the hydrogen peroxide resolution is lowered.

[Reference Example 3]
In Reference Example 1, the spent resin of the platinum group metal catalyst resin tower 93 after being operated for a long time was packed in a column for test to obtain a platinum group metal catalyst resin tower for test. Further, for comparison, a new resin was similarly packed in a test column to make a platinum group metal catalyst resin tower.

30 μg / L of hydrogen peroxide is added to ultrapure water (less than 1 μg / L of hydrogen peroxide) to prepare inlet water, and this inlet water is passed through each of the test columns described above at a water flow rate (SV) of 400 hr ^-1 . The hydrogen peroxide concentration of the outlet water after downward flow of water was measured (No. 1). The results are shown in Table 3.

In addition, as a load test, 400 μg / L of hydrogen peroxide is added to ultrapure water (less than 1 μg / L of hydrogen peroxide) to prepare a test inlet water, and the test inlet water is passed through each test column described above. Water flow (SV): 6400 hr.sup.- ^{1 After} 22 hours of downward flow of water, the operation was stopped. Then, pass inlet water containing 30 μg / L of hydrogen peroxide to ultrapure water (less than 1 μg / L of hydrogen peroxide) through each test column, and after 5 minutes (No. 2), 60 minutes (No) The hydrogen peroxide concentration of the outlet water of .3) was measured. The results are shown in Table 3.

Example 1
After the test in Reference Example 3, the resin of each test column is taken out, stored in ultra pure water (less than 1 μg / L hydrogen peroxide) for 2 weeks, and then refilled to obtain ultra pure water (1 μg hydrogen peroxide / L) The hydrogen peroxide concentration of the outlet water when passing through the inlet water to which 30 μg / L of hydrogen peroxide was added was measured. The results are shown in Table 4.

It can be seen from Table 4 that the hydrogen peroxide removal performance can be recovered by storing the used platinum-based catalyst in ultrapure water for a predetermined period.

Although the invention has been described in detail with particular embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.
This application is based on Japanese Patent Application 2017-240802 filed on Dec. 15, 2017, which is incorporated by reference in its entirety.

11-15, 31-35 Valve 21-25 Column 41-45, 51-55 Three-way valve

Claims

In a hydrogen peroxide removing method of removing hydrogen peroxide by passing hydrogen peroxide-containing water through a hydrogen peroxide removing device having a platinum-based catalyst charging vessel installed in parallel,
Hydrogen peroxide removal performance recovery operation of stopping the water supply of hydrogen peroxide-containing water to a part of the platinum-based catalyst filled container and storing the platinum-based catalyst filled in the container in ultrapure water for a predetermined period A method of removing hydrogen peroxide characterized in that
The hydrogen peroxide removal performance recovery operation according to claim 1, wherein the water in the container in which the water flow is stopped is replaced with ultrapure water, and the platinum catalyst is stored for a predetermined period in the ultrapure water in the container. Hydrogen peroxide removing method characterized in that
The hydrogen peroxide removal performance recovery operation according to claim 1, wherein the platinum-based catalyst in the container is removed from the container in which the water flow is stopped, and the removed platinum-based catalyst is stored in ultrapure water for a predetermined period. A method for removing hydrogen peroxide, comprising the step of refilling the container.
The method for removing hydrogen peroxide according to any one of claims 1 to 3, wherein a non-oxidizing gas is supplied to the ultrapure water.
The method for removing hydrogen peroxide according to claim 4, wherein the non-oxidizing gas is nitrogen gas.
The method for removing hydrogen peroxide according to any one of claims 1 to 5, wherein the ultrapure water is ultrapure water in which hydrogen is dissolved.
The hydrogen peroxide removing device according to any one of claims 1 to 6, wherein the hydrogen peroxide removing device is installed in an ultrapure water producing device, and the amount of water passing through the platinum-based catalyst filled container other than the part is A method of hydrogen peroxide removal characterized by increasing.
Parallel mounted platinum-based catalyst charging vessels,
Hydrogen peroxide-containing water passing means for passing hydrogen peroxide-containing water through each container;
Supply means for supplying non-oxidative gas or hydrogen dissolved water to each container;
A hydrogen peroxide removing device comprising: switching means for switching between hydrogen peroxide-containing water passing water and non-oxidizing gas or hydrogen dissolving water supply to each container.