JP7157142B2 - Anion exchange resin and water treatment method using the same - Google Patents

Description

The present invention relates to an anion exchange resin and a water treatment method using the same.

Conventionally, ultrapure water used in semiconductor manufacturing processes is produced using an ultrapure water production system. The ultrapure water production system includes, for example, a pretreatment unit that removes suspended solids in the raw water to obtain pretreated water, a total organic carbon (TOC) component and ion components in the pretreated water, a reverse osmosis membrane device and an ion It has a primary pure water production section that produces primary pure water by removing it using an exchange device and a secondary pure water production section that produces ultrapure water by removing trace amounts of impurities in the primary pure water. . Raw water includes city water, well water, groundwater, industrial water, etc., as well as used ultrapure water collected at points of use (POU) (hereinafter referred to as "collected water"). ) is used.

Such an ultrapure water production system generally uses an anion exchange resin or a cation exchange resin to remove ion components in the raw water. For example, as a device using ion exchange resin, in a large-scale ultrapure water production system, a multi-bed device in which cation exchange resin and anion exchange resin are packed in separate towers may be used. . In this double-bed device, a cation tower filled with a cation exchange resin and an anion tower filled with an anion exchange resin are connected in series, and a decarboxylation tower is provided between them (after the cation tower). A two-bed, three-tower system is generally used.

In addition, in a device using an ion exchange resin, a method is also known in which a functional group or metal having a specific function is introduced into the basic anion exchange resin to remove trace impurities in the primary pure water ( For example, see Patent Documents 1 and 2).

Here, among ion exchange resins, basic anion exchange resins have amines as their ion exchange groups. Therefore, a small amount of amines such as trimethylamine (hereinafter also referred to as TMA), dimethylamine, and monomethylamine leak out from the basic anion exchange resin. These amines generate an odor described as putrid fish odor. In particular, even a very small amount of TMA generates a considerable odor.

In the ultrapure water production system as described above, depending on the scale, about 100 L of ion exchange resin is used per resin tower, and several tens of such resin towers are arranged per ion exchange resin apparatus. be.

Therefore, when the basic anion-exchange resin inside the resin tower is replaced in a non-regenerative ion-exchange resin unit or the like, the odor of TMA pervades the surroundings. In particular, in a large-scale ultrapure water production system, there is a problem that a large amount of resin is exchanged at one time, and the odor increases considerably. Furthermore, there is also the problem that the odor reaches a place of use (POU: Point of Use) of ultrapure water such as a semiconductor manufacturing factory to which ultrapure water is supplied, causing discomfort to factory workers.

Here, as a countermeasure against the odor of the treated water of the basic anion exchange resin, the strongly basic anion exchange resin is heat-treated in a mixed state with the H-type cation exchange resin, and then the cation exchange resin is separated and the effluent is collected. A method using a reduced strongly basic anion exchange resin is known (see, for example, Patent Document 3). Further, as a method for removing the odor of treated water containing recovered treated water used in the food manufacturing industry, a method of passing odor-bearing water leaking from an anion exchange resin through a salt-form cation exchange resin is also known. (See Patent Document 4, for example).

However, the method of Patent Document 3 involves steps of mixing, heating, and separation, which increases the number of processes during the production of the ion-exchange resin, resulting in increased costs and longer delivery times. . In addition, although the method described in Patent Document 4 can reduce the odor in water, there is a problem that a sufficient effect as a countermeasure against odor when replacing the strongly basic anion exchange resin cannot be obtained.

JP-A-61-174987 Japanese Patent Publication No. 62-35838 JP 2007-75720 A JP 2015-24379 A

The present invention has been made to solve the above problems, and provides an odor-reduced anion exchange resin suitable for use in ultrapure water production systems and the like, and a water treatment method using the same. for the purpose.

The odor-suppressing anion exchange resin of the present invention comprises a basic anion exchange resin and 0.01 parts by mass or more and less than 5 parts by mass of an H-type strongly acidic cation with respect to 100 parts by mass of the basic anion exchange resin. It is characterized by being mixed with an ion exchange resin.

In the anion exchange resin of the present invention, the basic anion exchange resin and the H-type strongly acidic cation exchange resin are preferably not separated by backwashing.

The anion exchange resin of the present invention preferably contains a palladium-supported resin in which palladium is supported on the basic anion exchange resin.

In the anion exchange resin of the present invention, the basic anion exchange resin preferably contains a reducing resin having a sulfite group and/or a hydrogen sulfite group.

The water treatment method of the present invention is a water treatment method in which water to be treated is passed through an anion exchange resin. It is characterized by being an odor-suppressing anion exchange resin obtained by mixing 0.01 parts by mass or more and less than 5 parts by mass of an H-type strongly acidic cation exchange resin with respect to parts by mass.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an odor-reduced anion exchange resin suitable for an ultrapure water production system and a water treatment method using the same.

1 is a block diagram schematically showing an ultrapure water production system according to a first embodiment; FIG. 2 is a block diagram schematically showing an example of a primary pure water production section of the ultrapure water production system shown in FIG. 1; FIG. 3 is a block diagram schematically showing an example of a secondary pure water production section of the ultrapure water production system shown in FIG. 2; FIG.

An embodiment of the present invention will be described in detail below.
The anion exchange resin of the present embodiment is a mixture of a basic anion exchange resin and an H-type cation exchange resin, and the amount of the H-type cation exchange resin with respect to 100 parts by mass of the basic anion exchange resin is It is 0.01 mass part or more and less than 5 mass parts. If the amount of the H-type cation exchange resin is 5 parts by mass or more, the amount of the H-type cation exchange resin becomes excessive, impairing the anion exchange function. do not have. In the anion exchange resin of the present embodiment, the amount of the H-type cation exchange resin to the basic anion exchange resin is more preferably 0.1 parts by mass or more and 2 parts by mass or less. 0.5 parts by mass or more and 1.5 parts by mass or less is more preferable.

Strictly speaking, the anion exchange resin of the present embodiment corresponds to a mixed bed resin in which an anion exchange resin and a cation exchange resin are mixed. Since the amount is very small and it is suitable for use as an anion exchange resin, it is called an "anion exchange resin".

Basic anion exchange resins generate odors due to amines such as trimethylamine (TMA), dimethylamine, and monomethylamine when used. As the basic anion exchange resin, a known basic anion exchange resin can be used without particular limitation, and a weakly basic anion exchange resin having a primary amine, secondary amine or tertiary amine as an exchange group Resins and strongly basic anion exchange resins having quaternary ammonium groups as exchange groups can be mentioned. Examples of quaternary ammonium groups include trimethylammonium groups and dimethylethanolammonium groups. Moreover, these basic anion exchange resins generally have crosslinked polystyrene (styrene-divinylbenzene copolymer) or polyacrylic acid ester as a resin skeleton. Among these, a great effect can be obtained when a strongly basic anion exchange resin, which tends to emit an odor, is used.

The basic anion exchange resin usually has a specific gravity of 1.0 to 1.1 g/cm ³ and an exchange capacity of preferably 0.7 to 1.5 meq/mL, more preferably 1 to 1.5 meq/mL. be. Commercially available products of such a basic anion exchange resin include DUOLITE AGP manufactured by Dow Chemical Company, SAT20L manufactured by Mitsubishi Chemical Corporation, and the like.

The basic anion exchange resin may be in salt form or OH form. As a method of obtaining OH form from a salt-type basic anion exchange resin, a method of regenerating by passing an alkaline aqueous solution such as an aqueous sodium hydroxide solution or an aqueous potassium hydroxide solution through a salt-type basic anion exchange resin. There is If the basic anion exchange resin is of the OH type, which tends to emit an odor, a great odor suppressing effect can be obtained. When the basic anion exchange resin is OH type, the OH type conversion rate is preferably 99.95% or more.

As the basic anion exchange resin used in the present embodiment, a basic anion exchange resin, preferably a palladium-supported resin in which palladium (Pd) is supported on a strongly basic anion exchange resin, or platinum (Pt) is used. A supported platinum-supporting resin may also be used. A palladium-supported resin is obtained by passing an acidic solution of palladium chloride through a basic anion exchange resin. When the amount of palladium supported on the palladium-supporting resin is in the range of 0.1 g-Pd/L to 2 g-Pd/L, it exhibits a great effect in suppressing odor.

As the basic anion exchange resin used in the present embodiment, a reducing resin having a sulfite group (—SO ₃ ) or a hydrogen sulfite group (—SO ₃ H) may be used as the basic anion exchange resin. . The reducing resin can be obtained by passing an aqueous solution of sodium bisulfite or sodium sulfite at a concentration of about 1 to 5N through a basic anion exchange resin to ion-exchange sulfite groups or bisulfite groups. The basic anion exchange resin used for the reducing resin is preferably a strongly basic anion exchange resin. Also, the reducing resin may have both a sulfite group and a hydrogen sulfite group. When the total amount of the sulfite group and the hydrogen sulfite group in the reducing resin is 0.7 mol/L to 1.5 mol/L, it exhibits a great effect in suppressing odor. In addition, since the reducing resin and the cation exchange resin obtained as described above are more difficult to separate by backwashing than the anion exchange resin and the cation exchange resin before the above treatment, rarely separated into Therefore, the odor is stably suppressed, and the performance during use is also stable.

The H-type cation exchange resin is a cation exchange resin in which the exchange group is regenerated to H _- type. A weakly acidic cation exchange resin having a group (--COOH) as an exchange group can be mentioned. Cation exchange resins generally have crosslinked polystyrene (styrene-divinylbenzene copolymer) as a resin skeleton.

The H-type cation exchange resin usually has a specific gravity of 1.2 to 1.3 g/cm ³ and an exchange capacity of preferably 1.5 to 2.5 meq/mL, more preferably 2 to 2.5 meq/mL. be. The H-type cation exchange resin is obtained by passing an acidic aqueous solution such as hydrochloric acid through a salt-type cation exchange resin to regenerate it. The H-type conversion rate of the H-type cation exchange resin is preferably 99.95% or more. Preferably, the H-type cation exchange resin is a strongly acidic cation exchange resin. Commercially available strongly acidic cation exchange resins include DUOLITE CGP manufactured by Dow Chemical Company, SKT-20L manufactured by Mitsubishi Chemical Corporation, and the like.

The anion exchange resin of the present embodiment is obtained by mixing the basic anion exchange resin and the H-type cation exchange resin in the above ratio, and in the mixed state, water treatment etc. can be performed without separating the H-type cation exchange resin. is preferably applied to Therefore, a combination of the basic anion exchange resin and the H-type cation exchange resin that is difficult to be separated by backwashing is preferable. The conditions for this backwash separation are, for example, upward flow and LV=10 to 20 [m/hr]. In addition to the above, as a combination that is difficult to separate by backwashing, the sedimentation velocity distribution of the basic anion exchange resin and the H-type cation exchange resin measured under the same conditions is similar, and the sedimentation velocity distribution It is preferable that the velocity regions that are common to each other are included therein. The sedimentation velocity here may be an actually measured value or a theoretically determined value according to Allen's formula or the like.

The anion exchange resin of the present embodiment is produced by mixing the basic anion exchange resin and the H-type cation exchange resin in the proportions described above. As a mixing method, the basic anion exchange resin and the H-type cation exchange resin are accommodated in the resin tower at the above ratio, the resin is drained in the tower, and then nitrogen gas is supplied from the bottom of the resin tower. Examples include a method of pouring and mixing, and a method of mechanically stirring and mixing with a stirring motor or the like.

The water treatment method using the anion exchange resin of the present embodiment is a method of passing water to be treated through the anion exchange resin of the above embodiment. Production of pure water or ultrapure water is suitable for such water treatment.

A pure water production system using the anion exchange resin of the present embodiment includes, for example, a pure water production system having a pretreatment section and a primary pure water production section. Further, this pure water production system may be an ultrapure water production system having a secondary pure water production section downstream of the primary pure water production section of the pure water production system.

FIG. 1 is a block diagram schematically showing an ultrapure water production system 10 of this embodiment. The ultrapure water production system 10 of this embodiment has a pretreatment section 11 , a primary pure water production section 12 , a tank 13 and a secondary pure water production section 14 .

City water, well water, industrial water, or the like can be used as the raw water used in the ultrapure water production system 10 of the present embodiment.

In the ultrapure water production system 10, the pretreatment unit 11 is appropriately configured according to the quality of the raw water and the like, and removes suspended solids from the raw water to generate pretreated water. The pretreatment unit 11 is configured by appropriately selecting, for example, a sand filter device, a microfiltration device, or the like, and further includes a heat exchanger or the like for adjusting the temperature of the water to be treated as necessary.

The primary pure water production unit 12 removes ionic components, non-ionic components, and dissolved gas from the pretreated water to produce primary pure water, and supplies this primary pure water to the tank 13 . As the primary pure water production unit 12 using the anion exchange resin of the above embodiment, for example, as shown in FIG. A device having a resin tower 122a, a decarboxylation etc. 122b and an anion exchange resin tower 122c in series) 122, a reverse osmosis membrane device (RO) 123, an ultraviolet oxidation device (TOC-UV) 124, a mixed bed ion exchange device (MB ) 125 and a deaerator (DG: membrane deaerator or vacuum deaerator) 126 in this order. In the above configuration, the anion exchange resin of the embodiment is accommodated, for example, in an anion exchange resin tower of a two-bed, three-tower type apparatus.

The primary pure water has, for example, a total organic carbon (TOC) concentration of 5 μgC/L or less and a resistivity of 17 MΩ·cm or more.

The tank 13 stores primary pure water and supplies the required amount to the secondary pure water producing section 14 .

The secondary pure water production unit 14 removes trace impurities from the primary pure water to produce ultrapure water. As shown in FIG. 3, the secondary pure water production unit 14 includes a heat exchanger (HEX) 141, an ultraviolet oxidation device (TOC-UV) 142, a hydrogen peroxide removal device (H ₂ O ₂ removal device) 143 , degassing membrane device (MDG) 144 , non-regenerating mixed bed ion exchange resin device (Polisher) 145 and ultrafiltration device (UF) 146 . It should be noted that the secondary pure water production unit 14 does not necessarily have to include the above devices, and may be configured by combining the above devices as necessary.

In the above configuration, the heat exchanger 141 adjusts the temperature of the primary pure water supplied from the tank 13 as required. The ultraviolet oxidation device 142 irradiates the primary pure water with ultraviolet rays to decompose and remove trace organic substances in the water. The ultraviolet oxidation device 142 has, for example, an ultraviolet lamp and generates ultraviolet rays with a wavelength of around 185 nm. The UV oxidizer 142 may also generate UV light with a wavelength of around 254 nm.

The hydrogen peroxide removal device 143 is a device that decomposes and removes hydrogen peroxide in water. A reducing resin device or the like filled with a reducing resin having a sulfite group and/or a hydrogen sulfite group. In the secondary pure water production unit 14 of this configuration, the anion exchange resin of the above embodiment is the material of the palladium-carrying resin used in the palladium-carrying resin device or the material of the reducing resin used in the reducing resin device. is preferably Compared to the pretreatment section 11 and the primary pure water production section 12, these are arranged closer to the place where ultrapure water is used, such as a semiconductor manufacturing factory, so they are very effective in suppressing odors during resin replacement.

The degassing membrane device 144 is a device that decompresses the secondary side of a gas-permeable membrane and allows only dissolved gases in water flowing through the primary side to permeate to the secondary side for removal. Specifically, commercial products such as X50 and X40 manufactured by 3M and Separel manufactured by DIC can be used as the degassing membrane device 144 . The degassing membrane device 144 removes dissolved oxygen in the treated water of the hydrogen peroxide removing device 6 to generate treated water having a dissolved oxygen concentration (DO) of 1 μg/L or less, for example.

The non-regenerating mixed bed ion exchange resin device 145 has a mixed bed ion exchange resin in which a cation exchange resin and an anion exchange resin are mixed, and a trace amount of cation components in the treated water of the degassing membrane device and Absorbs and removes anions. In the non-regenerating mixed-bed ion exchange resin device 145, replacement is also performed according to the deterioration of the resin. Since it is mixed in approximately the same amount as the Therefore, the anion exchange resin in the non-regenerating mixed bed ion exchange resin apparatus 145 may not use the anion exchange resin of the present embodiment.

The non-regenerating mixed-bed ion-exchange resin device 145 has a strongly acidic cation-exchange resin and a weakly acidic cation-exchange resin as the cation-exchange resin, and an anion-exchange resin as a strongly basic anion-exchange resin and a weakly acidic cation-exchange resin. Basic anion exchange resins can be mentioned. Examples of commercially available mixed-bed ion exchange resins include N-Lite MBSP and MBGP manufactured by Nomura Micro Science.

The ultrafiltration membrane device 146 removes fine particles having a particle size of 50 nm or more, preferably 20 nm or more, more preferably 10 nm or more, for example, to produce ultrapure water. As for the water quality of ultrapure water, for example, the number of fine particles having a particle diameter of 50 nm or more is 50 pcs. /L or less, a total organic carbon (TOC) concentration of 1 μgC/L or less, and a resistivity of 18 MΩ·cm or more.

According to the anion exchange resin of the embodiment described above, it is possible to remarkably suppress the odor caused by amines such as trimethylamine (TMA), dimethylamine, and monomethylamine of the basic anion exchange resin. Therefore, it is suitable for water treatment such as production of pure water and production of ultrapure water. For example, when used in an ultrapure water production system, odors during resin exchange can be significantly reduced.

Next, examples will be described. The invention is not limited to the following examples.

(Example 1)
In a container made of polyethylene with an internal capacity of 2 L, 500 g of a reducing resin obtained by ion-exchanging DUOLITE AGP, a strongly basic anion exchange resin manufactured by Dow Chemical Co., with sulfurous acid, and an H-type cation exchange resin (manufactured by Dow Chemical Co., Ltd. , DUOLITE CGP) was accommodated, and the upper opening was covered with vinyl and sealed with a lid. After storing this for 30 days, the lid was removed and a gas detection tube (Gastec gas detection tube, amines (model number: 180 or 180L)) was pierced into the vinyl to measure the concentration of amines in the gas inside the beaker. . The obtained measured value was converted into the trimethylamine concentration. Table 1 shows the results.
When a backwashing separation test was conducted using 500 g of the resin of Example 1, most of the H-type cation exchange resin remained mixed with the reducing resin and was not separated. (Backwash development rate 10%, backwash time 10 minutes)

(Example 2)
In a container made of polyethylene with an internal capacity of 2 L, 500 g of DUOLITE AGP, a strongly basic anion exchange resin manufactured by Dow Chemical Co., and 5 g of H-type cation exchange resin (DUOLITE CGP, manufactured by Dow Chemical) were accommodated. A test similar to that of Example 1 was performed.
When a backwash separation test was conducted using 500 g of the resin of Example 2, separation occurred. (Backwash development rate 10%, backwash time 10 minutes)

(Example 3)
500 g of Lewatit K7333, a catalyst resin in which palladium is supported on a basic anion exchange resin manufactured by LANXESS, and 5 g of an H-type cation exchange resin (DUOLITE CGP, manufactured by Dow Chemical) are placed in a polyethylene container having an internal volume of 2 L. The same test as in Example 1 was performed, except that it was accommodated.
When 500 g of the resin of Example 3 was used to conduct a backwashing separation test, most of the H-type cation exchange resin remained mixed with the catalyst resin and was not separated. (Backwash development rate 10%, backwash time 10 minutes)

(Comparative example 1)
The same test as in Example 1 was performed, except that 500 g of a strongly basic anion exchange resin (DUOLITE AGP manufactured by Dow Chemical Co.) was placed in a polyethylene container.

(Comparative example 2)
The same test as in Example 1 was carried out, except that 500 g of the same reducing resin as in Example 1 was placed in a polyethylene container.

(Comparative Example 3)
In a polyethylene container, 500 g of the same reducing resin as in Example 1 and 5 g of Na-type cation exchange resin (manufactured by Dow Chemical, DUOLITE CGP ion-exchanged to Na-type) were accommodated. The same test as in 1 was performed. The results of each comparative example are shown in Table 1 together with those of the examples.
When a backwash separation test was conducted using 500 g of the resin of Comparative Example 3, the resin was separated into two layers cleanly. (Backwash development rate 10%, backwash time 10 minutes)

From Table 1, in Example 1 in which 1 part by mass of H-type cation exchange resin was mixed with 100 parts by mass of basic anion exchange resin (reducing resin), comparison was made without mixing H-type cation exchange resin. Compared with Examples 1 and 2 and Comparative Example 3 in which a salt-type cation exchange resin was mixed, it can be seen that the generation of odors of amines represented by TMA can be effectively suppressed.

10... Ultrapure water production system, 11... Pretreatment unit, 12... Primary pure water production unit, 13... Tank, 14... Secondary pure water production unit

Claims (4)

An anion exchange resin used in water treatment,
A mixture of a basic anion exchange resin and an H-type cation exchange resin of 0.01 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the basic anion exchange resin,
When backwashing is performed at LV 10 to 20 [m / hr], at least part of the basic anion exchange resin and the H-type cation exchange resin remain mixed to suppress the odor. Anion exchange resin.
The basic anion exchange resin is a palladium-supported resin on which palladium is supported,
2. The anion exchange resin according to claim 1, wherein the H-type cation exchange resin is an H-type cation exchange resin having sulfonic acid groups as ion exchange groups . The basic anion exchange resin is a reducing resin having a sulfite group and/or a hydrogen sulfite group ,
2. The anion exchange resin according to claim 1, wherein the H-type cation exchange resin is an H-type cation exchange resin having sulfonic acid groups as ion exchange groups . A water treatment method in which water to be treated is passed through an anion exchange resin,
The anion exchange resin is a mixture of a basic anion exchange resin and an H-type cation exchange resin of 0.01 parts by mass or more and less than 5 parts by mass with respect to 100 parts by mass of the basic anion exchange resin. and at least a part of the basic anion exchange resin and the H-type cation exchange resin remains mixed when backwashing is performed at LV 10 to 20 [m / hr], and an odor-suppressed anion A water treatment method characterized in that it is an exchange resin.

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