JPH01258794A - UV oxidation decomposition equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention uses ultraviolet rays to decompose and remove organic matter that becomes a problem when recycling pure water used in semiconductor manufacturing factories, etc. The present invention relates to an ultraviolet oxidation and decomposition device that oxidizes and decomposes organic substances, especially low-molecular alcohols, that cannot be decomposed by other means by irradiating them.

[Prior art] In recent years, water has been used as manufacturing water and cleaning water for semi-dedicated integrated circuits, etc.
BACKGROUND ART High purity pure water or ultrapure water is produced using recycled water.

Therefore, in order to remove impurities such as ion sources, particles, viable bacteria, and salts contained in the water to be treated, the water to be treated is passed through an ion exchange resin tower, a membrane treatment device, an activated carbon tower, etc. for treatment. There is.

Furthermore, the amount of total organic carbon contained in the water to be treated (To-ta
l Organic Carbon, hereinafter referred to as TOC. ), the decomposition treatment of dissolved organic matter is being considered.
Membrane separation treatment is applied to high-molecular organic substances, and ultraviolet oxidation treatment is applied to low-molecular organic substances.

[Problems to be Solved by the Invention] Therefore, various studies were conducted on ultraviolet P;A oxidation treatment of water to be treated containing isopropyl alcohol, which is particularly difficult to decompose using conventional methods among the low-molecular-weight organic substances. , focusing on the amount of lamp power per 1 m3 of water to be treated from the ultraviolet radiation lamp used in the ultraviolet oxidation decomposition equipment,
The optimal oxidation conditions were set.

First, as an ultraviolet ray oxidation decomposition device installed in a treatment tank through which water to be treated flows, a jacket made of quartz glass or the like with good ultraviolet transmittance was used, and a low-pressure mercury lamp or a high-pressure mercury lamp was installed inside the jacket.

Next, the distance between the inner surface of the treatment tank through which the water to be treated flows and the outer surface of the jacket, that is, the thickness of the water layer, was set within a predetermined range for each lamp.

Further, an oxidizing agent such as hydrogen peroxide was mixed into the water to be treated in the treatment tank, and an oxidative decomposition reaction of organic matter by ultraviolet irradiation was utilized.

Considering that the treatment efficiency is affected by changes in the TOC concentration in the water to be treated, the initial T of the water to be treated is
The amount of lamp power required per 1 m3 of water to be treated to decompose the OC concentration to 90% was determined through experiments, and a calculation formula was calculated.

[Means for Solving the Problems] The present invention has been made in view of the above, and includes an ultraviolet oxidation decomposition device consisting of a low-pressure mercury lamp or a high-pressure mercury lamp supported in a jacket, installed in a treatment tank, and In the apparatus, in which water to be treated is passed through, an oxidizing agent is mixed therein, and ultraviolet rays are irradiated from the lamp, the thickness of the water layer between the outer surface of the jacket and the inner surface of the treatment tank is 100 to 100 mm in the case of a low-pressure mercury lamp. 200mm.

In the case of high pressure mercury lamps, it should be 200 to 400 mm,
Furthermore, the amount of lamp power (E!) per unit of water to be treated from the lamp required for the decomposition treatment of 90% of the organic matter corresponding to the initial TOC concentration of the organic matter.

:KW-hr/mI') is calculated by the following formula.

Here, a: constant (low pressure mercury lamp: 0.45 to 0.55 high pressure mercury lamp: 0.55 to 0.65), b: constant (low pressure mercury lamp: -0,1 to -0,2 high pressure mercury lamp) lamp 20
．． 3 to 0.4), C0: initial TOC concentration (ppm).

The purpose is to decompose isopropyl alcohol, which is a low-molecular-weight organic substance in the water to be treated, and to provide highly purified water or ultrapure water.

A further object of the present invention is to provide an ultraviolet ray oxidation decomposition device that has the amount of ultraviolet rays necessary for ultraviolet oxidation decomposition treatment regardless of the difference in the initial TOCiJ degree in the water to be treated.

[Example] The present invention will be described below based on an illustrated example. 1st
The figure shows the pilot eggplant 1 to apparatus according to the present invention. In figure 5, 1 is a cylindrical treatment tank made of stainless steel, etc., and inside it is a cylindrical treatment tank made of quartz glass with good ultraviolet transmittance. A shaped jacket 2 is arranged. A low pressure mercury lamp 3 is supported within this jacket. Further, an outlet 1a for outflowing the water to be treated is formed at one end of the treatment tank, and an inlet 1b for injecting the same at the other end. 4 is the inner surface of the processing tank 1 and the jacket 2
shows the aqueous layer ring through which the water to be treated flows between the outer surface of the

Further, 6 is a tank in which water to be treated 8 containing isopropyl alcohol as an organic substance is retained, and a stirrer 7 is installed in the center of the tank. Note that 5 indicates a pump for circulating the water to be treated.

When operating the apparatus configured in this way, first, a required amount of hydrogen peroxide is added to the water to be treated 8 containing isopropyl alcohol retained in the tank 6, and the agitator 7
Activate.

By opening and closing a valve (not shown), etc., and operating the pump 5, the water to be treated is injected into the treatment tank through the inlet 1b of the treatment tank 1, flows through the inside, and is treated through the outlet 1a. Water flows out of the tank and is injected into the tank.

When the water to be treated flows through the treatment tank, a low-pressure mercury lamp supported in the jacket 2 is turned on to irradiate it with single wavelength ultraviolet rays, thereby oxidizing and decomposing the organic matter.

Next, using the pilot device shown in FIG.
80nm, different from 380m+, and initial TOC concentration 5
ppm, and using a 30W low-pressure mercury lamp as a lamp, each water J! 9 of isopropyl alcohol in thickness
The decomposition properties down to 0% were measured. The measurement results are shown in FIG.

As is clear from FIG. 2, it can be seen that the decomposition treatment efficiency, expressed as the amount of lamp power per 1 m3 of water to be treated, expressed as the amount of UV irradiation for 90% TOC decomposition, becomes better as the water layer ring becomes larger.

Then, based on FIG. 2, the amount of ultraviolet irradiation necessary to decompose TOC to 90% was determined, and the relationship with each water layer ring is shown in FIG. 3.

In addition, the amount of ultraviolet irradiation when using a high-pressure mercury lamp as the lamp and changing the initial TOC concentration by making each water layer ring different in the same way as above, and when changing the initial TOC concentration using a low-pressure mercury lamp. Figure 4 shows the processing efficiency expressed in .

As can be seen from Figures 2 to 4, when a low-pressure mercury lamp is used, regardless of the initial TOC concentration of the water to be treated, the TOC can be reduced to 90% from a water layer ring of about 100 mm.
The amount of UV irradiation required to cause decomposition is low and almost constant.

Furthermore, even if the aqueous layer ring is increased in size, the amount of ultraviolet irradiation, that is, the amount of lamp power required for decomposing organic matter, remains approximately constant, so the aqueous layer ring is 100 to 200 m m
is optimal. Even if it is made larger than this, the treatment efficiency will hardly change, so not only will the treatment tank become larger, but
Furthermore, when using a high-pressure mercury lamp, the optimal water layer ring is 200 to 400 mm, as described above.

In addition, using the pilot device described above, the water layer ring was set to 140 mm and a low-pressure mercury lamp was mounted on the jacket inside the treatment tank, and the water layer ring was set to 280 mm and the same high-pressure mercury lamp was supported. FIG. 5 shows the measurement results of the amount of ultraviolet irradiation required to decompose TOC to 90% by changing the initial TOC concentration, that is, the amount of lamp power per bottle of water to be treated.

From the same figure, the amount of lamp electricity required per 1 m3 of water to be treated to decompose 90% of organic matter corresponding to the initial TOC concentration (
EL: KW-hr/rn') is determined by the following formula.

Here, a: constant (low pressure mercury lamp: 0.45 to 0.55 high pressure mercury lamp: 0.55 to 0.65), b: constant (low pressure mercury lamp: -0.1 to -0.2 high pressure mercury lamp) Lamp: 0
．． 3 to 0.4), C0: initial TOC concentration (pp garden).

Note that the constants a and b in the case of a low-pressure mercury lamp and a high-pressure mercury lamp can be determined from FIG. 5, respectively.

In the above example, the case where the ultraviolet ray oxidation decomposition device according to the present invention was used in a test pilot device was explained.
By installing this device after a membrane separation device in a pure water or ultrapure water production device, it can be used as production water for semiconductor integrated circuits used in a wastewater recovery system or the like.

[Effects of the Invention] As is clear from the above description, the ultraviolet oxidation decomposition device according to the present invention can efficiently oxidize and decompose water containing isopropyl alcohol under optimal oxidation conditions. It can be widely used to generate ultrapure water used in the manufacture of semiconductor integrated circuits, etc., and to recycle its wastewater.

Furthermore, despite the difference in the initial TOC concentration in the water to be treated, it is possible to obtain an apparatus having a unified low-pressure mercury lamp or high-pressure mercury lamp, and its industrial utility value is great.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a test pilot device having an ultraviolet ray oxidation decomposition device according to the present invention, Fig. 2 is a diagram showing the relationship between the amount of ultraviolet irradiation and TO (J1 degree), Figs. 3 and 4 5 is a diagram showing the relationship between the water layer thickness and the required amount of decomposing ultraviolet ray irradiation, and FIG. 5 is a diagram showing the relationship between the initial TOC concentration and the required amount of decomposing ultraviolet irradiation.

Claims (2)

[Claims] (1) Water to be treated containing isopropyl alcohol as an organic substance is passed through a treatment tank equipped with an ultraviolet oxidation decomposition device, an oxidizing agent is mixed into the water to be treated, and a low pressure is supported within the jacket of the ultraviolet oxidation decomposition device. In an apparatus that irradiates light from a mercury lamp onto the water to be treated to oxidize and decompose the organic matter, the water layer thickness of the water to be treated between the outer surface of the jacket and the inner surface of the treatment tank is 100 to 200 mm. , the initial TO of the organic matter
Lamp power consumption (EL: KW・hr/m^3) from a low-pressure mercury lamp per 1 m^3 of the water to be treated necessary for decomposition of 90% of organic matter corresponding to the C (total organic carbon content) concentration
, EL=10^(^a^・^l^o^g^C^o^+^b
^) Here, a: constant (0.45 to 0.55), b: constant (-0.1 to -0.2), Co: initial TOC concentration (ppm). Oxidation decomposition equipment. (2) Water to be treated containing isopropyl alcohol as an organic substance is passed through a treatment tank equipped with an ultraviolet oxidation decomposition device, an oxidizing agent is mixed into the water to be treated, and a high pressure is supported within the jacket of the ultraviolet oxidation decomposition device. In an apparatus that oxidizes and decomposes the organic matter by irradiating the water from a mercury lamp with light from a mercury lamp, the water layer thickness of the water to be treated between the outer surface of the jacket and the inner surface of the treatment tank is 200 to 400 mm. , the initial TO of the organic matter
Lamp power consumption (EL: KW・hr/m^3) from a high-pressure mercury lamp per 1 m^3 of the water to be treated necessary for decomposing 90% of organic matter corresponding to the C (total organic carbon content) concentration
, EL=10^(^a^・^l^o^g^C^o^+^b
^) Here, a: constant (0.55 to 0.65), b: constant (0.3 to 0.4), Co: initial TOC concentration (ppm), UV oxidation decomposition characterized by: Device.