JPH11262757A - Apparatus for producing ultrapure water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the increase in a dissolved oxygen concentration in ultrapure water by a method in which raw water is irradiated with ultraviolet rays, free radicals in the raw water are adsorbed, and ionic components are removed from the raw water in which free radicals are adsorbed. SOLUTION: Primary pure water produced by a primary system is supplied to an ultraviolet lamp oxidation device 9 and irradiated with ultraviolet rays of 180-190 nm. Next, the water is sent to a free radical adsorption device 10 to adsorb contained free radicals. The device 10 is filled with a free radical adsorbent having the crosslinked structure of a phenol-formalin based condensate. The raw water with free radicals adsorbed is sent to a mixed bed type ion exchange apparatus 11 filled with a strongly basic anion exchange resin, and ionic components are removed. In this way, the dissolved oxygen concentration of the treated water can be reduced as compared with that of water passed through a by-path line 12 without passing through the free radical adsorption device 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrapure water producing apparatus for producing ultrapure water, which is widely used in the electronics industry for manufacturing semiconductor devices and liquid crystal displays, nuclear power plants, pharmaceutical manufacturing plants and the like. is there.

[0002]

2. Description of the Related Art Conventionally, in a semiconductor device (LSI), a liquid crystal display (LCD), or a manufacturing process of pharmaceuticals, the content of ionic substances, fine particles, organic substances, dissolved gases, viable bacteria, and the like is extremely small. Ultrapure water is used. In particular, in the electronics industry, the demand for the purity of ultrapure water is becoming more and more severe with the increase in the degree of integration of LSIs.

[0003] Generally, the production of ultrapure water involves a pretreatment system for removing suspended components in raw water, ionic substances, fine particles,
It is performed by a combination of a primary system for removing organic matter, dissolved gas, viable bacteria and the like, and a secondary system for the purpose of precision finishing of primary purified water obtained from the primary system.

Incidentally, in a secondary system for the purpose of precision finishing of primary purified water, as a treatment method for reducing the concentration of organic substances in ultrapure water, a membrane treatment by an ion exchange treatment or a reverse osmosis method is performed. There is known a method of irradiating the primary purified water with ultraviolet rays to decompose dissolved organic substances, and then removing the decomposed organic substances by a mixed-bed ion exchange apparatus. In addition, as ultraviolet rays for irradiating primary purified water to be treated, 180 to 190 nm (especially 184.9 nm).
It is also known that the decomposition of dissolved organic matter can be efficiently achieved by using ultraviolet rays having a wavelength of (1) (Japanese Patent Laid-Open No. 1-164488), and these techniques reduce the concentration of organic matter in ultrapure water. Has greatly contributed to

[0005]

However, a primary system is used to convert primary pure water, which is water to be treated whose organic matter concentration has been reduced to an extremely low concentration, into an ultraviolet oxidizing device for generating ultraviolet light having a wavelength of 180 to 190 nm. When treated in a secondary system having a mixed bed type ion exchange device, the concentration of dissolved oxygen in the water to be treated that has passed through the ion exchange device is higher than that of primary pure water before treatment in the secondary system. The problem of rising occurred. That is,
When reducing the dissolved oxygen concentration by the primary system and treating the pure water whose organic matter concentration has been reduced to an extremely low concentration by the conventional secondary system, the dissolved oxygen concentration in the resulting ultrapure water may increase. There was a problem that it became significant. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an ultrapure water production apparatus that substantially prevents an increase in dissolved oxygen concentration in ultrapure water.

[0006]

As described above, when the primary pure water in which the organic substance concentration and the dissolved oxygen concentration are reduced to a low concentration by the primary system is treated by the conventional secondary system, ion exchange is performed. The concentration of dissolved oxygen in the water to be treated that has passed through the device increases significantly compared to the primary pure water before being treated in the secondary system.

[0007] Regarding this problem, the present inventors have studied diligently, primary pure water in which the concentration of organic substances has been reduced to an extremely low concentration, to ultraviolet light having a wavelength of 180 to 190 nm, in particular, 184.9 nm. When ultraviolet rays having a wavelength peak were irradiated by an ultraviolet oxidizer, it was found that a small amount of OH radicals (hydroxy radicals) that could not react with organic substances leaked at the ultraviolet oxidizer outlet.

As a mechanism for generating a small amount of OH radicals, there is proposed a mechanism for generating a small amount of OH radicals by decomposition of water with ultraviolet rays as shown in the following formula.

H ₂ O + hν → OH It has also been found that the leaked OH radicals react with each other in a negative part to generate hydrogen peroxide. As shown in the following equation, the mechanism by which a small amount of hydrogen peroxide is generated is that the OH radical generated by ultraviolet decomposition of water cannot react with a small amount of organic matter in primary purified water and leaks, and the leaked OH radical The mechanism by which they react and form is presented.

OH + .OH + H ₂ O ₂ Hydrogen peroxide generated by the leaked OH radicals is decomposed into oxygen and water near the surface of the ion exchange resin filled in the ion exchange device. It is presumed that the concentration of dissolved oxygen in the water to be treated that has passed through the mixed-bed ion exchange device has increased compared to the primary pure water before treatment in the secondary system.

Therefore, in order to prevent an increase in the dissolved oxygen loss of the water to be treated that has passed through the mixed-bed type ion exchanger, OH radicals that could not react with a trace amount of organic substances leaking from the ultraviolet oxidizer are removed. Before the water to be treated is supplied to the ion exchange device, it is necessary to remove the water from the water to be treated.

Therefore, in the ultrapure water production apparatus according to the present invention, there is provided an ultraviolet irradiation apparatus for irradiating the water to be treated with ultraviolet rays, and a radical adsorption apparatus for adsorbing radicals contained in the water to be treated irradiated with the ultraviolet rays. And an ion exchange device for removing ionic components from the water to be treated on which the radicals have been adsorbed.

In the present invention, the water to be treated is 180 to
The organic matter dissolved in the water to be treated is almost completely decomposed into an organic acid or carbon dioxide by being introduced into an ultraviolet oxidizing apparatus for irradiating ultraviolet light having a wavelength of 190 nm. Next, the water to be treated is introduced into a radical adsorption device that adsorbs radicals in the water to be treated, and radicals that have not reacted with organic substances in the ultraviolet oxidizing device are removed. Finally, the water to be treated, which has been treated in the radical adsorption device, is introduced into a mixed-bed ion exchange device, where the ionic components in the water to be treated are removed.

According to the apparatus for producing ultrapure water of the present invention, the water to be treated introduced into the ultraviolet irradiation device is passed through the radical adsorption device and introduced into the ion exchange device. Since the generation of oxygen via hydrogen peroxide can be prevented, the concentration of dissolved oxygen contained in the produced ultrapure water can be reduced.

[0015] Further, the water to be treated introduced into the ultraviolet irradiation apparatus is passed through the radical adsorption apparatus and introduced into the ion exchange apparatus, so that the radicals generated by the ultraviolet irradiation apparatus and oxidizing substances such as hydrogen peroxide can be eliminated. Since the contact with the ion exchange resin filled in the ion exchange device can be prevented, the oxidative deterioration of the ion exchange resin can be prevented.

Further, the water to be treated introduced into the ultraviolet irradiation device is passed through the radical adsorption device and introduced into the ion exchange device, so that the water generated by the ultraviolet irradiation device and oxidizing substances such as hydrogen peroxide are generated. Since it is possible to prevent the desorption of the ion exchange group of the resulting ion exchange device,
It is possible to substantially prevent increases in organic substances and ionic components in the water to be treated in the ion exchange device.

In the present invention, as the ultraviolet irradiation device, ultraviolet light having a wavelength of 180 to 190 nm, particularly 18
It is preferable to generate ultraviolet light having a wavelength of 4.9 nm,
At this time, ultraviolet light having a sterilizing wavelength of 254 nm may be simultaneously generated. The ultraviolet oxidizer is not particularly limited, but in the present invention, it is preferable to use a low-pressure ultraviolet lamp oxidizer. The reaction by this ultraviolet ray is as follows: (1) OH radical (hydroxy radical) generated from primary pure water
(2) Organic substances in the primary purified water, which is the water to be treated, are oxidatively decomposed to the level of an organic acid such as carboxylic acid, and (3) furthermore, partly oxidatively decomposed to carbon dioxide.

(1) H ₂ O + hν → OH (2) RC + OH → RCOOH (3) RCOOH + OH → CO ₂ + H
₂ O In addition, when the amount of dissolved organic matter in the primary water to be treated is very small, (4) hydrogen peroxide is generated by a reaction between OH radicals.

(4) .OH + .OH → H ₂ O ₂ Further, in the present invention, a phenolic hydroxyl group, thiol, or the like is provided on the surface of the radical adsorber for adsorbing radicals generated by the ultraviolet oxidizer. A radical adsorbing device having a resin filled therein can be suitably used. At this time, as a resin having a phenolic hydroxyl group, a thiol, or the like on its surface and filling the radical adsorbing device, a resin that adsorbs radicals efficiently without denaturation such as decomposition upon reaction with radicals is desired. For example, those having a crosslinked structure of a phenol-formalin condensate (for example, trade name “Duolite XAD”)
-761 "(Rohm & Haas) and a thiol-based chelate resin (trade name" MA-A "(Hokuetsu Carbon Industries Co., Ltd.)).

If necessary, an ion-exchange resin ion-exchanged with ions having a radical-adsorbing ability, a chemical injection of a polymerization terminator, a resin having a polymerization terminator supported on a substrate, and the like can also be used.

As an ion exchange device for removing carbon dioxide, organic acids or other ionic components from the water to be treated, a non-regeneration type packed with a strongly basic anion exchange resin and a strongly acidic cation exchange resin is used. A mixed bed type ion exchange device can be preferably used. As the anion and cation exchange resin used in the ion exchange apparatus, it is desirable to use a new or cation-exchange resin which has no crushing, has high ion exchange performance, and has no elution.

In the apparatus for producing ultrapure water of the present invention, it is possible to insert another device, for example, a degassing device such as a degassing film, between the constituent devices. Other equipment may be interposed as long as the order of the ion exchange device is not changed.

The ultrapure water obtained by the present invention is supplied to a point of use and used. The water quality of the ultrapure water is 18 MΩ · cm or more in electrical conductivity, TOC concentration,
And the dissolved oxygen concentration is increased to about 1 μg / l or less.

In particular, the apparatus of the present invention has a remarkable effect when treating primary pure water having a DO of 10 ppb or less.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and detailed description is omitted. Further, the present invention is not limited to the present embodiment without departing from the gist thereof. FIG. 3 is a diagram showing an embodiment of a primary pure water producing apparatus for producing primary pure water as an embodiment of the present invention.

In FIG. 3, reference numeral 1 denotes a membrane pretreatment device (Kuraray Co., Ltd., ML) for removing suspended components in raw water.
Reference numeral 2 denotes a reverse osmosis membrane device (Toray Industries, Inc., SU-720). Reference numerals 3 and 6
Is a mixed bed type ion exchange apparatus, and uses a strongly basic anion exchange resin Duolite A113pl as an anion exchange resin.
us (R & H) with 33 L, and a strongly acidic cation exchange resin Duolite C20 (R & H
And 23 L of these were used, and these were regenerated and converted into OH type and H type, and then mixed and filled. In addition,
The ion exchange capacity of the mixed bed type ion exchange devices 3 and 6 is 0.5.
9 equivalents / L-Resin. Reference numeral 4 indicates a reverse osmosis membrane device (Nitto Denko Corporation, NTR-759.UP), and reference numeral 5 indicates a low-pressure ultraviolet lamp oxidation device (Chiyoda Kohan Co., Ltd., TDFL-4, irradiation amount 0.25 kWh). / M ³ )
It is. The low-pressure ultraviolet lamp oxidizing device 5 generates ultraviolet light having a wavelength around 185 nm as a peak. Symbol 7 is
Water-sealed vacuum pump (Nikoku Kikai Kogyo Co., Ltd., 25 BET)
250 L / min, 25 Torr) 8 were connected, and Teralet S type (Nippon Steel Chemical Co., Ltd., packing diameter 250 mm; packed bed height 4000 mm) was filled as a filler, and the volume ratio of nitrogen gas to the water to be treated. Is a nitrogen gas addition type vacuum deaerator with 0.03: 1.

The present embodiment and this comparative example were carried out on primary pure water produced using the primary pure water producing apparatus thus constructed.

Example 1 and Comparative Examples 1 and 2 FIG.
It is a figure showing composition of an ultrapure water production device (secondary system) which is one example of the present invention.

In FIG. 1, reference numeral 9 denotes a low-pressure ultraviolet lamp oxidizing apparatus (TDFL-4, Chiyoda Kohan Co., Ltd., irradiation amount: 0.25 kWh / m ³ ), which generates ultraviolet light having a peak at a wavelength around 185 nm. I do. Reference numeral 10 denotes a radical adsorber filled with 56 L of a substance that adsorbs a radical, and a duolite XAD-7 having a crosslinked bridge of a phenol / formalin condensate as the substance that adsorbs the radical.
61 (Rohm & Haas). Reference numeral 11 denotes a mixed-bed ion exchange apparatus, which is composed of 33 L of a strong basic anion exchange resin Duolite A113plus (Rohm & Haas) as an anion exchange resin and a strongly acidic cation exchange resin Duolite C20 (C20) as a cation exchange resin. Rohm & Haas Co., Ltd.), and these were regenerated and converted into OH type and H type before mixing and filling. In addition, the mixed bed type ion exchange device 11
Has an ion exchange capacity of 0.9 equivalent / L-Resin.

First, Atsugi-shi water was used as raw water to be supplied to the membrane pretreatment device 1, and primary pure water was generated by a primary system. The average water quality of the obtained primary pure water was as follows: electric conductivity: 18.0 MΩ · cm, TOC concentration: 1.1 μg / L,
The dissolved oxygen concentration was 0.7 μg / L. Next, primary pure water was supplied from the mixed bed type ion exchange device 6 to the secondary system at a flow rate of 1.6 m ³ / h, and ultrapure water was continuously produced over time via the path A (Example 1). ).

(Comparative Example 1) Except that water was passed through the mixed bed type ion exchange device 11 without passing through the radical adsorption device 10 via the bypass line 12 in FIG. 1 (path B),
Ultrapure water was produced continuously with the lapse of time in exactly the same manner as in Example 1 (Comparative Example 1).

Table 1 shows the dissolution in the water to be treated measured at the inlet of the low-pressure ultraviolet lamp oxidizer 9, the radical adsorber 10, and the outlet of the mixed-bed ion exchanger 11 in Example 1 and Comparative Examples 1 and 2. It shows the oxygen concentration. In addition, the dissolved oxygen concentration in the water to be treated at each outlet is a result measured using a high-sensitivity dissolved oxygen meter (Orbis Fair Laboratories, model 3600).

[0033]

[Table 1] As is clear from Table 1, in Example 1 described above, the concentration of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizing device 9 was 0.7 μg / L, and the concentration of the dissolved oxygen at the outlet of the mixed-bed ion exchange device 11 was 0.7 μg / L. The dissolved oxygen concentration in the water to be treated is 0.1.
It has decreased to 3 μg / L. On the other hand, in Comparative Example I, the concentration of dissolved oxygen in the water to be treated was 0.7 μg / L in the population of the low-pressure ultraviolet lamp oxidizer 9, whereas the bypass installed in the subsequent stage of the low-pressure ultraviolet lamp oxidizer 9. After passing through the line 12, the mixed bed type ion exchange device 1
The dissolved oxygen concentration in the water to be treated treated in step 1 is 6.4 μg
/ L. This is because, in Comparative Example 1, the mixed-bed ion exchange device 11
Is connected, hydrogen peroxide is generated from radicals generated in the low-pressure ultraviolet lamp oxidizing device 9, and the hydrogen peroxide is converted into oxygen and water in the vicinity of the surface of the ion-exchange resin filled in the mixed-bed type ion-exchange device 11. It is considered that this was due to decomposition.

(Comparative Example 2) As shown in FIG. 2, the radical adsorption apparatus 10 and the mixed-bed ion exchange apparatus 1 shown in FIG.
Ultrapure water was produced continuously with the lapse of time in the same manner as in Example 1 except that the positions 1 and 2 were exchanged with each other (Comparative Example 2).

As is clear from Table 1, in Example 1 described above, the concentration of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizing device 9 was 0.7 μg / L, and the mixed-bed ion-exchange device 11 The concentration of dissolved oxygen in the water to be treated at the outlet of is reduced to 0.3 μg / L. On the other hand, in Comparative Example 2, while the concentration of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizer 9 was 0.7 μg / L, the mixed oxygen installed at the subsequent stage of the low-pressure ultraviolet lamp oxidizer 9 was used. The concentration of dissolved oxygen in the water to be treated at the outlet of the bed-type ion exchange device 11 had increased to 6.3 μg / L. This is because, in Comparative Example 2, as in Comparative Example 1, the mixed-bed ion exchange device 11
Is connected, hydrogen peroxide is generated from radicals generated in the low-pressure ultraviolet lamp oxidizing device 9, and the hydrogen peroxide is converted into oxygen and water in the vicinity of the surface of the ion-exchange resin filled in the mixed-bed type ion-exchange device 11. It is considered that this was due to decomposition. Since the dissolved oxygen generated by the mixed-bed ion exchange device 11 disposed downstream of the low-pressure ultraviolet lamp oxidation device 9 cannot be removed by the radical adsorption device, the dissolved oxygen concentration at the outlet of the radical adsorption device 10 is 6.2 μg. / L.

Accordingly, in the first embodiment, an increase in the dissolved oxygen concentration in the water to be treated (ultra pure water) at the outlet of the mixed bed type ion exchange device 11 is prevented. An increase in the dissolved oxygen concentration at the outlet of the mixed bed ion exchange device 11 cannot be prevented, and in Comparative Example 2, the radical adsorber 10 cannot efficiently remove dissolved oxygen in the water to be treated. As a result, an increase in the concentration of dissolved oxygen at the outlet of the radical adsorption device 10 was observed.

Example 2 and Comparative Examples 3 and 4 In FIG. 1, except that the thiol-based chelate resin MA-A (Hokuetsu Carbon Industry Co., Ltd.) was filled as a substance for adsorbing radicals in the radical adsorber. Ultrapure water was continuously produced with the passage of time in the same manner as in Example 1 (Example 2). (Comparative Example 3) Via the bypass line 12 in FIG.
Ultrapure water was continuously produced with time in exactly the same manner as in Example 2 except that water was passed through the mixed-bed ion exchange device 11 without passing through the radical adsorption device 10 (path B) ( Comparative example 3).

Table 2 shows that, in Example 2, Comparative Examples 3 and 4, the in-treatment water measured at the inlet of the low-pressure ultraviolet lamp oxidizer 9, the radical adsorber 10, and the outlet of the mixed-bed ion exchanger 11 was measured. It shows the dissolved oxygen concentration. In addition, the dissolved oxygen concentration in the water to be treated at each outlet is a result measured using a high-sensitivity dissolved oxygen meter (Orbis Fair Laboratories, model 3600).

[0039]

[Table 2] As is clear from Table 2, in Example 2, the concentration of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizer 9 was 0.7 μg / L, and the outlet of the mixed-bed ion exchanger 11 was , The concentration of dissolved oxygen in the water to be treated has decreased to 0.4 μg / L. On the other hand, in Comparative Example 8, while the concentration of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizing device 9 was 0.7 μg / L, the bypass installed at the subsequent stage of the low-pressure ultraviolet lamp oxidizing device 9 was used. The concentration of dissolved oxygen in the water to be treated passed through the line 12 and treated by the mixed-bed ion exchanger 11 is 6.3.
μg / L. This is because, in Comparative Example 3, since the mixed-bed ion exchange device 11 was connected to the subsequent stage of the low-pressure ultraviolet lamp oxidizing device 9, hydrogen peroxide was generated from radicals generated in the low-pressure ultraviolet lamp oxidizing device 9, and the hydrogen peroxide was generated. This is probably because the ion-exchange resin filled in the mixed-bed ion exchange device 11 was decomposed into oxygen and water in the vicinity of the surface.

COMPARATIVE EXAMPLE 4 As shown in FIG. 2, the radical adsorption apparatus 10 and the mixed-bed ion exchange apparatus 1 shown in FIG.
Ultrapure water was produced continuously over time in exactly the same manner as in Example 2 except that the positions 1 and 2 were interchanged (Comparative Example 4).

As is apparent from Table 2, in Example 2 described above, the regression of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizer 9 was 0.7 μg / L, and the mixed-bed ion exchange device was used. The dissolved oxygen concentration in the water to be treated at the outlet of No. 11 has decreased to 0.4 μg / L. On the other hand, in Comparative Example 4, the concentration of dissolved oxygen in the water to be treated at the inlet of the low-pressure ultraviolet lamp oxidizer 9 was 0.7 μg / L, whereas the mixed oxygen installed at the subsequent stage of the low-pressure ultraviolet lamp oxidizer 9 was used. The concentration of dissolved oxygen in the water to be treated at the outlet of the bed-type ion exchange device 11 had risen to 6.4 μg / L. This is because, in Comparative Example 2, as in Comparative Example 1, the mixed-bed ion exchange device 11 is provided after the low-pressure ultraviolet lamp oxidizing device 9.
Is connected, hydrogen peroxide is generated from radicals generated in the low-pressure ultraviolet lamp oxidizer 9, and the hydrogen peroxide is converted into oxygen and water in the vicinity of the surface of the ion exchange resin charged in the mixed bed type ion exchanger 11. It is considered that this was due to decomposition. Since the dissolved oxygen generated by the mixed-bed ion exchange device 11 disposed downstream of the low-pressure ultraviolet lamp oxidation device 9 cannot be removed by the radical adsorption device 10, the dissolved oxygen concentration at the outlet of the radical adsorption device 10 is 6. It was 3 μg / L.

Therefore, in Example 2, the increase in the concentration of dissolved oxygen in the water to be treated (ultra pure water) at the outlet of the mixed bed type ion exchange device 11 was prevented, but in Comparative Examples 3 and 4, It is not possible to prevent an increase in the concentration of dissolved oxygen at the outlet of the mixed bed type ion exchange device 11, and in Comparative Example 4, the radical adsorption device 10 can effectively remove dissolved oxygen in the water to be treated. As a result, an increase in the dissolved oxygen concentration at the outlet of the radical adsorption device 10 was observed.

[0043]

As described in detail above, according to the present invention,
By passing the water to be treated introduced into the ultraviolet irradiation device through the radical adsorption device and into the ion exchange device,
Since the generation of oxygen via hydrogen peroxide from radicals generated by the ultraviolet irradiation device can be prevented, the concentration of dissolved oxygen contained in the produced ultrapure water can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an ultrapure water production apparatus (secondary system) according to Examples 1 and 2.

FIG. 2 is a diagram showing a configuration of an ultrapure water production apparatus (secondary system) according to Comparative Examples 2 and 4.

FIG. 3 is a diagram showing an embodiment of a primary pure water producing apparatus for producing primary pure water as an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Membrane pre-processing apparatus 2 ... Reverse osmosis membrane apparatus 3 ... Mixed bed type ion exchange apparatus 4 ... Reverse osmosis membrane apparatus 5 ... Low pressure ultraviolet lamp oxidation apparatus 6 ... Mixed bed type ion exchange apparatus 7 ... Vacuum deaerator 8 Water ring vacuum pump 9 Low pressure ultraviolet lamp oxidation device 10 Radical adsorption device 11 Mixed bed ion exchange device 12 Bypass line

Claims (4)

[Claims] An ultraviolet irradiation device that irradiates ultraviolet rays to the water to be treated; a radical adsorption device that adsorbs radicals contained in the water to be irradiated with the ultraviolet radiation; and a water adsorption device that adsorbs the radicals. An ultrapure water production apparatus, comprising: an ion exchange apparatus for removing an ion component. 2. The ultrapure water production apparatus according to claim 1, wherein the ultraviolet light generated by the ultraviolet irradiation device has a wavelength of 180 to 190 nm. 3. The method according to claim 1, wherein the radical adsorbing device is provided with phenol.
The ultrapure water production apparatus according to claim 1, wherein a formalin-based condensate or a thiol-based chelate resin is used. 4. The apparatus according to claim 1, further comprising a primary pure water producing apparatus for producing primary pure water as raw water from the raw water before the ultraviolet irradiation apparatus. 2. The ultrapure water production apparatus according to claim 1.