JP4334777B2 - Preservation method of ion exchange resin packed tower - Google Patents

Description

【００４８】
表１に示されるように、いずれの製品も不純物レベルは同レベルにあった。したがって、本発明に係る保存方法によれば、いったん停止した過酸化水素水精製装置であっても、再生することなく再度、過酸化水素水の精製をスタートさせることができるという不連続運転が可能となる。また再度、精製をスタートさせる際に、新品とほとんど変わらないイオン交換樹脂を過酸化水素水の精製に供することができ、長期間にわたって、イオン交換樹脂を繰り返し使用することが可能となる。
【図面の簡単な説明】
【図１】本発明で使用されるイオン交換樹脂塔の概略断面図を示す。
【符号の説明】
１………イオン交換樹脂塔
２………液供給ノズル
３………液排出口
４………充填塔の蓋
５………イオン交換樹脂
６………超純水または過酸化水素水[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for storing an ion exchange resin tower. More specifically, the present invention relates to a method for preserving an ion exchange resin tower that enables discontinuous operation, allows the ion exchange resin to be used repeatedly over a long period of time, and maintains a high level of impurity removal of hydrogen peroxide.
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
In a semiconductor manufacturing process, a high-purity hydrogen peroxide solution is used as a wafer cleaning solution. In such a semiconductor application, in order to improve the reliability of the semiconductor cleaning apparatus, a high-purity hydrogen peroxide solution whose impurity content is controlled to a very low level is required.
[0003]
As a method for purifying hydrogen peroxide, a method is known in which hydrogen peroxide is brought into contact with an anion exchange resin or cation exchange resin packed in an ion exchange resin tower to remove impurities.
By the way, there are cases where the hydrogen peroxide purification apparatus in operation is forced to be stopped for a period of several hours or several days due to operational reasons such as product filling balance or regular maintenance of the factory.
[0004]
Conventionally, in the hydrogen peroxide purification apparatus once stopped in this way, when the purification of hydrogen peroxide water is started again, bubbles are entangled with the ion exchange resin in the purification apparatus, and the flow rate cannot be taken. The impurity removal level may be remarkably lowered, or the hydrogen peroxide solution may be rapidly decomposed to deteriorate the ion exchange resin. For this reason, the ion exchange resin that has been used for purification has been regenerated again or, in some cases, replaced with a new ion exchange resin. However, redoing or renewing with a new ion exchange resin in this way has the disadvantage that it is extremely inefficient from an economic point of view.
[0005]
For this reason, in Japanese Patent Application Laid-Open No. 2000-272908, water replacement is performed by passing 20 times or more of the amount of ion exchange resin through an ion exchange resin tower through which hydrogen peroxide solution is passed. It has been proposed for use in the purification of hydrogen oxide water.
However, the method described in JP-A-2000-272908 focuses on the chemical protection of the ion exchange resin and is insufficient for maintaining a high level of purification. For this reason, the ion exchange band may be disturbed, and the impurity removal level may be lowered when the hydrogen peroxide solution is purified again.
[0006]
OBJECT OF THE INVENTION
The present invention has been made to solve the problems associated with the above-described prior art, enables discontinuous operation, and enables repeated use of an ion exchange resin over a long period of time. It is an object of the present invention to provide a method for preserving an ion exchange resin tower that can maintain the impurity removal level.
[0007]
Summary of the Invention
The preservation method of the ion exchange resin tower of the present invention is:
In the ion exchange resin tower in which the hydrogen peroxide solution is supplied to the ion exchange resin tower by flowing down from the upper liquid supply nozzle through the ion exchange resin bed to obtain purified hydrogen peroxide water from the lower liquid discharge port.
In the non-operating state (when refining is interrupted or terminated), after stopping the supply of hydrogen peroxide solution, the purified water is immediately flowed down from the upper liquid supply nozzle through the ion exchange resin bed, and the inside of the packed tower Without bringing the ion exchange resin bed into contact with air, the hydrogen peroxide solution in the resin tower is driven out, replaced with pure water, and the ion exchange resin bed is immersed in pure water.
[0008]
According to the present invention as described above, immediately after stopping the supply of hydrogen peroxide from the upper liquid supply nozzle in the ion exchange resin tower, as in the case of treating the hydrogen peroxide solution, The hydrogen peroxide solution in the tower is expelled and replaced with pure water. For this reason, bubbles do not get entangled with the ion exchange resin, and the ion exchange band that raises and raises the ion exchange resin is not disturbed. Moreover, since the ion exchange resin bed is immersed in high-purity pure water without being in contact with air, it is possible to suppress deterioration of the ion exchange resin and a reduction in purification capacity.
[0009]
The space velocity during hydrogen peroxide liquid passing and SV _p, the space velocity during the pure water flow-through when the SV _w, SV _w / SV _p is in the range of 0.90 to 1.10 preferable. When pure water is passed in this way, the hydrogen peroxide solution can be driven out and replaced with pure water without disturbing the exchange band in the ion exchange resin bed.
As the ion exchange resin, an H-type strongly acidic cation exchange resin, a hydrogen carbonate type or a carbonate type anion exchange resin, or an F ⁻ type anion exchange resin is used.
[0010]
In the present invention, it is desirable to use ultrapure water having a purity of 17 MΩ · cm or more as pure water to be passed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the preservation | save method of the ion exchange resin packed tower which concerns on this invention is demonstrated concretely. In the present specification, “%”, “ppm”, “ppb” and “ppt” all represent “% by weight”, “weight ppm”, “weight ppb” and “weight ppt”.
The preservation method of the ion exchange resin tower according to the present invention is as follows.
In the ion exchange resin tower in which the hydrogen peroxide solution is supplied to the ion exchange resin tower by flowing down from the upper liquid supply nozzle through the ion exchange resin bed to obtain purified hydrogen peroxide water from the lower liquid discharge port.
In a non-operating state (when refining is interrupted or terminated), after stopping the supply of hydrogen peroxide solution, the purified water is immediately flowed down from the upper liquid supply nozzle through the ion exchange resin bed, and the packed tower Without bringing the ion exchange resin bed inside into contact with air, the hydrogen peroxide solution in the resin tower is driven out and replaced with pure water, and the ion exchange resin bed is immersed in pure water.
[0012]
An example of the ion exchange resin packed tower used in the method for storing an ion exchange resin tower according to the present invention is shown in FIG.
FIG. 1 is a schematic cross-sectional view of an ion exchange resin tower used in the present invention. In FIG. 1, subscript 1 is an ion exchange resin tower, 2 is a liquid supply nozzle, 3 is a liquid outlet, and 4 is a packed tower. Lids, 5 are ion exchange resins, and 6 is ultrapure water or hydrogen peroxide water. The material used for the wetted part of hydrogen peroxide solution and ultrapure water is low elution vinyl chloride resin, fluorine resin such as PFA, PTFE, etc. It is preferably used because of less contamination. Further, stainless steel or carbon steel coated with a low-elution vinyl chloride resin, fluorine resin such as PFA, PTFE or the like can be used.
[0013]
The hydrogen peroxide solution is flowed down from the liquid supply nozzle 2 by means such as a liquid feed pump from an external line. Also, the water level is continuously extracted from the liquid discharge port 3 by the water level sensor, and the water level is always kept constant. The hydrogen peroxide solution that was passed through and contacted with the ion exchange resin was introduced into another ion exchange resin tower as necessary, and after contacted with the other ion exchange resin, collected in a tank to adjust the concentration. After product inspection, it is stored, filled and shipped.
[0014]
The preservation method according to the present invention can be applied to known ion exchange resins without any particular limitation, and includes cation exchange resins such as H-type strongly acidic cation exchange resins, anion exchange resins, carbonate ion types or bicarbonate ion types. The present invention can be applied to cation exchange resins such as hydroxide ion type and fluoride ion type, and can also be applied to mixed beds of anion exchange resins and cation exchange resins.
[0015]
In particular, the present invention is suitable when the ion exchange resin is an H-type cation exchange resin, a hydrogen carbonate type or a carbonate type anion exchange resin, or an F ⁻ type anion exchange resin.
In general, the cation exchange resin is preferably a cation exchange resin having a network molecular structure in which a sulfonic acid group is introduced into a styrene-divinylbenzene crosslinked copolymer. As such an H ⁺ type cation exchange resin, for example, PK216, SK-1B, IR-120B or the like is used.
[0016]
For the H ⁺ type cation exchange resin, an operation of treating the cation exchange resin with a downflow inorganic acid aqueous solution (regenerant) and then washing with an upflow ultrapure water is one step, and the step is repeated twice or more. What was reproduced | regenerated by this is preferable. As the inorganic acid, known inorganic acids such as sulfuric acid and hydrochloric acid are used. As the inorganic acid concentration in the aqueous regenerant solution, a concentration in the range of 5 to 15% by weight, preferably 5 to 12% by weight, is suitably used. The amount of such a regenerant used is preferably 3 times or more, preferably 4 to 12 times the amount (volume) of the cation exchange resin to be treated.
[0017]
Usually, the contact between the cationic resin and the regenerant aqueous solution is carried out by passing the regenerant aqueous solution through, then extruding and washing with ultrapure water. It is desirable to repeat the cycle. Specifically, it is particularly desirable to repeat the descending flow solution of the regenerant aqueous solution and the rising flow solution of ultrapure water two or more times. By repeating the aqueous solution of inorganic acid and ultrapure water in this way, the cation exchange resin contracts and swells, so that the inside of the exchange resin can be washed.
[0018]
In addition, the anion exchange resin used in the present invention is generally a strongly basic resin obtained by chloromethylating a styrene-divinylbenzene crosslinked copolymer and then quaternizing it with trimethylamine or dimethylethanolamine. Resin, styrene-divinylbenzene cross-linked copolymer, weakly basic resin with primary to tertiary amine as exchange group, acrylic acid cross-linked polymer with tertiary amine as exchange group, pyridyl group or substituted A pyridine-based anion exchange resin composed of a polymer having a pyridyl group is regenerated to a desired salt form by a regenerant. In particular, a strongly basic anion exchange resin having a quaternary ammonium group is preferably used. Many types of quaternary ammonium group anion exchange resins are commercially available. For example, Diaion PA series (eg PA-316, PA416), SA series (eg SA-10A, SA-20A), Amberlite IRA series (eg IRA-400, IRA-410, IRA-900, IRA-904). ) Is a typical example. These resins are generally marketed in the chloride ion type.
[0019]
The regenerant of the anion exchange resin is appropriately selected depending on the intended ion type, but in the case of carbonate ion and hydrogen carbonate ion type anion exchange resins, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, ammonium carbonate Known carbonates or bicarbonates such as ammonium bicarbonate are used as the regenerant. In the case of a fluoride ion type anion exchange resin, sodium fluoride, potassium fluoride, or ammonium fluoride is used as a regenerant.
[0020]
The salt concentration in the aqueous regenerant solution is 5 to 15% by weight, preferably 5 to 12% by weight for the carbonate ion type or bicarbonate ion type, and 1 to 4% by weight, preferably 1 to 2% by weight for the fluoride ion type. Those in the range are preferably used. The amount of the regenerant aqueous solution used is preferably 3 times or more, preferably 4 to 8 times the resin amount (volume) of the anion exchange resin to be treated.
[0021]
As the hydrogen peroxide solution to be purified, those produced by a known production method such as an anthraquinone auto-oxidation method or a direct synthesis method in which hydrogen and oxygen are directly reacted are used. Moreover, you may use the hydrogen peroxide solution which refine | purified crude hydrogen peroxide solution beforehand using adsorption resin, chelate resin, a reverse osmosis membrane, etc.
This hydrogen peroxide solution usually contains impurities in the order of several ppb to several tens of ppm. As impurities, Ag, Al, As, Au, B, Ba, Be, Bi, Ca, Cd, Co, Cr, Fe, Ga, Ge, In, K, Li, Mg, Mo, Na, Nb, Ni, Examples thereof include metal ion impurities such as Pb, Pd, Pt, Sb, Sr, Ta, Ti, Tl, V, Zn, and Zr, silicon oxide compound impurities, and organic impurities. This impurity is derived from, for example, a residual working fluid of anthraquinone, water used during production (extraction, distillation, dilution), components floating in the air, and materials of production equipment.
[0022]
Although there is no restriction | limiting in particular about the density | concentration of the hydrogen peroxide solution used, Usually, 1 to 70 weight%, Preferably it is 1 to 60 weight%.
[Ion exchange resin filling]
The ion exchange resin tower is previously filled with regenerated ion exchange resin. It is desirable that the ion exchange resin in the packed column is packed in a volume of 40 to 80%, preferably 45 to 75% of the packed column internal volume.
[0023]
The ion exchange resin may be filled by opening the lid 4 at the top of the resin tower and pouring the ion exchange resin in a suspension with pure water. When the ion exchange resin is poured, the pure water may be discharged from the liquid discharge port 3 at the bottom of the resin tower as necessary in order to prevent the ion exchange resin and pure water from overflowing from the ion exchange tower. . After the ion exchange resin packed tower is filled with the ion exchange resin, pure water is passed from the liquid supply nozzle in the upper part of the resin tower by the descending flowing liquid.
[0024]
When the suspension of ion exchange resin and pure water is allowed to flow into the ion exchange resin tower and when pure water is passed through, the water surface is made higher than the top surface of the ion exchange resin bed, Keep the replacement resin bed away from the air. It is desirable that the difference between the uppermost surface of the ion-exchange resin bed in the resin tower and the water surface is in the range of 10 to 20 cm, preferably 12 to 18 cm. In this way, there is no unevenness on the top surface of the ion exchange resin bed, and it becomes a laminar downward flow and the resin bed is exposed above the water surface even if there is some pressure fluctuation. There is no.
[0025]
The space velocity (SV _w ) when pure water passes through the packed tower is not particularly limited, and is desirably in the range of 5 to 40 Hr ⁻¹ , preferably 10 to 30 Hr ⁻¹ . The pure water introduced into the ion exchange resin tower 1 is made to flow evenly downward from the liquid supply nozzle 2 inside the resin tower. Further, it is desirable that BV _w (bed volume: a unit representing how many times the volume of the ion exchange resin is processed) when passing pure water is in the range of 3 to 7, preferably 3 to 6. As pure water to be passed, it is desirable to use ultrapure water having a purity of 17 MΩ · cm or more.
[0026]
[Hydrogen peroxide solution]
Next, the hydrogen peroxide solution descends from the liquid supply nozzle 2 into the resin tower 1 filled with such an ion exchange resin. Further, the water level is always kept constant by the water level sensor, and simultaneously with the hydrogen peroxide solution passage, the hydrogen peroxide solution treated from the liquid discharge port 3 is continuously extracted to the outside.
[0027]
It is desirable that the space velocity (SV _p ) when passing hydrogen peroxide solution is in the range of 5 to 40 Hr ⁻¹ , preferably 10 to 30 Hr ⁻¹ . The hydrogen peroxide solution introduced into the resin tower 1 is made to flow evenly downward from the liquid supply nozzle 2 inside the resin tower.
The liquid temperature is generally room temperature, but when contacting with a hydrogen carbonate type or carbonate type anion exchange resin, it is preferably controlled to 5 ° C. or lower in order to suppress decomposition of the hydrogen peroxide solution.
[0028]
When purifying the hydrogen peroxide solution, it is desirable to use a combination of a plurality of ion exchange resin towers filled with the ion exchange resin as described above.
As a combination of preferable ion exchange resin towers,
1) Cation exchange resin tower → Anion exchange resin tower
2) Cation exchange resin tower → Anion exchange resin tower → Cation exchange resin tower
3) Anion exchange resin tower → cation exchange resin tower, etc.
[0029]
Among these, a combination of a cation exchange resin packed tower → anion exchange resin packed tower → cation exchange resin packed tower is suitable, and in particular, H ⁺ type cation exchange resin packed tower → fluoride type anion exchange resin packed tower → carbonic acid or carbonic acid Impurities can be removed to a very high degree by carrying out hydrogen peroxide treatment in a combination of a hydrogen-type anion exchange resin packed tower and a cation exchange resin packed tower.
[0030]
After contacting the raw hydrogen peroxide solution and the cation exchange resin in this way, contacting with the anion exchange resin, and further contacting with the cation exchange resin, a trace amount of Na ⁺ contained as an impurity in the anion exchange resin, Since K ⁺ , Al ^{3+ and the} like can be removed, metal ion impurities can be removed to an extremely high level (ppt or sub-ppt order). Moreover, when a fluoride type anion exchange resin is used, the silicon component contained in hydrogen peroxide water can be removed. When a carbonate ion type or hydrogen carbonate ion type anion exchange resin is used as the anion exchange resin, counter ions such as Na ⁺ , K ⁺ , and Al ³⁺ to be removed are carbonate ions or hydrogen carbonate ions. After cation exchange, it is volatilized as carbon dioxide, which is desirable because it does not remain in the hydrogen peroxide solution.
[0031]
When treated with an H ⁺ type cation exchange resin in the previous stage, the hydrogen peroxide solution may contain more H ⁺ than is generated by the dissociation of hydrogen peroxide, and is adsorbed on this H ⁺ and anion exchange resin. The generated HCO ₃ ⁻ may neutralize to generate heat. For this reason, when processing hydrogen peroxide solution with an anion exchange resin, it is desirable to cool to a low temperature of 5 ° C. or less.
[0032]
Thus, also when combining several ion exchange resin towers, the preservation | save method of the ion exchange resin packed tower which concerns on this invention is suitable.
[Water replacement of ion-exchange resin packed tower]
In the present invention, after the purification of the hydrogen peroxide solution is completed or interrupted in this way, after the supply of the hydrogen peroxide solution is stopped in the non-operating state, the pure water is immediately ionized from the upper liquid supply nozzle. By flowing down in the exchange resin bed, the hydrogen peroxide solution in the resin tower is driven out and replaced with pure water without bringing the ion exchange resin bed in the resin tower into contact with air. Immerse in pure water.
[0033]
The purity of water used for water replacement is ultrapure water having a specific resistance of 17 MΩ · cm or more. Usually, it is desirable to perform water replacement immediately after purifying the hydrogen peroxide solution.
Further, when refining the ion-exchange resin tower stored after interruption is resumed, it is desirable to wash the ion-exchange resin tower with water just before passing the hydrogen peroxide solution. This is because ions released from a small amount from the ion exchange band during storage of the ion exchange resin are discharged.
[0034]
It is desirable that the space velocity (SV _w ) when pure water is passed is in the range of 5 to 40 Hr ⁻¹ , preferably 10 to 30 Hr ⁻¹ .
The pure water introduced into the packed tower 1 is made to flow evenly downward from the liquid supply nozzle 2 inside the resin tower.
BV _w (bed volume: a unit representing how many times the volume of the ion exchange resin has been processed) when pure water is passed differs depending on the state of the ion exchange resin tower. For example, when the hydrogen peroxide solution has just been purified, BV _w is desirably in the range of 5 to 40, preferably 15 to 30. Also After interrupting the purification, in the case of restarting the purification of aqueous hydrogen peroxide, in the liquid passage of pure water liquid passage immediately preceding hydrogen peroxide, BV _w is 3-7, the range preferably from 3 to 6 It is desirable to make it.
[0035]
The water flow temperature of pure water may normally be room temperature (20-30 ° C.). However, in the hydrogen carbonate type or carbonate type anion exchange resin tower, water in the ion exchange resin layer is used to suppress decomposition of the hydrogen peroxide solution. It is desirable to use pure water cooled to 6-8 ° C. at the beginning of the replacement. Incidentally, the space velocity during hydrogen peroxide liquid passing and SV _p, the space velocity during the pure water flow-through when the SV _w, SV _w / SV _p is 0.90 to 1.10, preferably 0 It is desirable to be in the range of .95 to 1.05.
[0036]
When water is replaced by passing pure water through the ion exchange resin tower, the water surface is made higher than the uppermost surface of the ion exchange resin bed so that the ion exchange resin bed does not come into contact with air. It is desirable that the difference between the uppermost surface of the ion-exchange resin bed in the tower and the water surface is in the range of 10 to 20 cm, preferably 12 to 18 cm. In this way, there is no unevenness on the top surface of the ion exchange resin bed, and it becomes a laminar downward flow and the resin bed is exposed above the water surface even if there is some pressure fluctuation. There is no.
[0037]
According to such a storage method, if the storage period is 1 to 3 days, bubbles do not get entangled with the ion exchange resin, and the bubbles grow to lift the ion exchange resin and disturb the ion exchange band. There is no. In addition, if the ion exchange resin is stored in this manner, the flow rate will not decrease when the hydrogen peroxide solution is once again resumed in the hydrogen peroxide solution purifier once stopped. Since the purification capacity is not lowered, a high impurity removal level can be maintained. In the storage method according to the present invention, when storing for a long period of 3 days or longer, the ion exchange band may be disturbed. Therefore, it is desirable to restart the purification process of the hydrogen peroxide solution within 3 days.
[0038]
When purifying with an ion exchange resin stored by the storage method according to the present invention, the purification is stopped and restarted many times in the middle without being regenerated until the purification capacity of the ion exchange resin is completed. However, the purification capacity can maintain a high removal capacity that is the same as that of continuous operation.
According to the storage method according to the present invention, discontinuous operation and intermittent operation are possible, ion exchange resin can be repeatedly used over a long period of time, and it is possible to perform a purification treatment with a high impurity removal level of hydrogen peroxide solution. To do.
[0039]
【The invention's effect】
According to the present invention, even if the hydrogen peroxide solution purifier is once stopped, discontinuous operation is possible in which the purification of the hydrogen peroxide solution can be started again without being regenerated. When the purification is started again, an ion exchange resin that is almost the same as a new one can be used for the purification of hydrogen peroxide solution, and can be used repeatedly over a long period of time.
[0040]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to this Example at all.
Open the lid of preparation <br/> exchange column of an ion exchange resin column, while water from the bottom of the ion exchange resin column, regenerated ion exchange resin (H ⁺ -type cation exchange resin, F ^- type anion exchange resin, HCO ₃ ^2- type anion exchange resin) was put in each ion exchange resin tower together with ultrapure water. Two H ⁺ -type cation exchange resin towers were prepared and used for the first and second stage treatments.
[0041]
The water level was maintained so that the upper surface of the ion exchange resin bed was not exposed from the water surface.
The lid was closed, and ultrapure water (17 MΩ · cm or more) was uniformly passed through the upper liquid supply nozzle in the exchange tower while draining water from the lower liquid outlet of the ion exchange resin tower. During running, the water surface was kept high by about 15 cm from the upper surface of the ion exchange resin.
SV _w at the time of ultra-pure water flow-through is a 22.5Hr ^-1, BV was 5.
[0042]
Hydrogen peroxide solution flow <br/> Stopping the flow of ultrapure water by switching the valve, uniformly hydrogen peroxide solution from the same solution supply nozzle to the bottom, H ⁺ type cation exchange resin tower The liquids were passed in the order of → F ⁻ type anion exchange resin tower → HCO ₃ ^2- type anion exchange resin tower → H ⁺ type cation exchange resin tower.
[0043]
The SV at the time of passing hydrogen peroxide water was 22.5 Hr ^{−1 in} any ion exchange resin tower. The liquid flow through the HCO ₃ ^2- type anion exchange resin tower was performed while cooling to -3 ° C. During the passage, the water surface was kept high by about 15 cm from the upper surface of the cation exchange resin. In addition, the raw material hydrogen peroxide water / ultra pure water mixed liquid at the initial stage of purification was recovered without continuously passing through each column.
[0044]
Stop operation After purification, the valve of each ion-exchange resin tower was switched to stop the flow of hydrogen peroxide water and switch to ultrapure water flow. Further, the valve of the liquid discharge port was also switched, and the mixed liquid of hydrogen peroxide water and ultrapure water was collected without flowing to other ion exchange resin towers. At this time, SV _w was 22.5 Hr ⁻¹ and BV _w was 3.75. The HCO ₃ ^2- type anion exchange resin tower used ultrapure water cooled to 6-8 ° C.
[0045]
After the hydrogen peroxide solution was replaced with ultrapure water, ultrapure water was further passed. The SV _w at the time of water flow is 22.5 Hr ^−1, and BV _w is 11.25 in the first stage and the second stage in the H ⁺ type cation exchange resin tower, and 18 in the F ⁻ type anion exchange resin tower. .25 for the HCO ₃ ^2- type anion exchange resin tower.
Resumption of operation After purifying the hydrogen peroxide solution for 6 hours by the above operation, each ion exchange resin tower was replaced with water and left for 12 hours (the purified hydrogen peroxide solution was used as the product (1)). And). Again, after purifying the hydrogen peroxide solution for 6 hours in the same ion exchange tower, each ion exchange resin tower was again replaced with water by the above operation and left for 12 hours (the purified hydrogen peroxide solution was used as the product ▲ 2)). Further, the ion exchange resin tower was purified with hydrogen peroxide solution for 6 hours in the same ion exchange tower (the purified hydrogen peroxide solution at this time is designated as product (3)).
[0046]
The amount of impurities was analyzed for the obtained products (1) to (3). The results are shown in Table 1.
Si content was evaluated by flameless atomic absorption, anions and cations were evaluated by ion chromatography, and other metal impurities were evaluated by ICP-MS.
[0047]
[Table 1]

[0048]
As shown in Table 1, all the products had the same impurity level. Therefore, according to the storage method according to the present invention, discontinuous operation is possible in which purification of hydrogen peroxide solution can be started again without regeneration, even if the hydrogen peroxide solution purification apparatus has been stopped. It becomes. In addition, when the purification is started again, an ion exchange resin that is almost the same as a new one can be used for the purification of hydrogen peroxide solution, and the ion exchange resin can be used repeatedly over a long period of time.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view of an ion exchange resin tower used in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ......... Ion-exchange resin tower 2 ......... Liquid supply nozzle 3 ......... Liquid discharge port 4 ......... Cover tower cover 5 ...... Ion exchange resin 6 ...... Ultra pure water or hydrogen peroxide water

Claims (4)

In the ion exchange resin tower in which the hydrogen peroxide solution is supplied to the ion exchange resin tower by flowing down from the upper liquid supply nozzle through the ion exchange resin bed to obtain purified hydrogen peroxide water from the lower liquid discharge port.
In a non-operating state, pure water is flowed down from the upper liquid supply nozzle through the ion exchange resin bed, so that the hydrogen peroxide solution in the resin tower can be reduced without bringing the ion exchange resin bed in the packed tower into contact with air. A method for preserving an ion exchange resin tower, wherein the ion exchange resin bed is immersed in pure water after being driven out and replaced with pure water. The space velocity during hydrogen peroxide descending flow solution and SV _p, the space velocity during the pure water descending flow fluid when the SV _w, SV _w / SV _p is in the range of 0.90 to 1.10 The preservation | save method of the ion exchange resin tower | column of Claim 1 characterized by the above-mentioned. The ion exchange resin packed tower according to claim 1 or 2, wherein the ion exchange resin is an H-type strongly acidic cation exchange resin, a hydrogen carbonate type or a carbonate type anion exchange resin, or an F ^- type anion exchange resin. Method. The method for preserving an ion exchange resin tower according to any one of claims 1 to 3, wherein ultrapure water having a purity of 17 MΩ · cm or more is used as pure water to be passed.

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