JP4760648B2 - Pure water production equipment - Google Patents

Description

  The present invention relates to an apparatus for producing pure water, and more particularly, an apparatus for producing pure water using urea-containing nitrogen compound-containing water such as urea, thiourea, sulfonylurea, allylurea, guanidine, acetylthiourea, and phenylurea as treated water (raw water). About.

I. In the manufacture of pure water used in various industries such as semiconductor manufacturing factory, liquid crystal manufacturing factory, pharmaceutical industry, food industry, electric power industry, etc. or consumer use or research facilities, etc., the TOC component contained in raw water (treated water) A method of oxidizing and decomposing to an ionic organic acid using an oxidizing agent such as ozone, hydrogen peroxide, persulfuric acid or hypochlorous acid, or an ultraviolet oxidizer, and adsorbing and removing it to an ion exchange resin in the latter stage (Japanese Patent Laid-Open No. 11) -99395), a method of decomposing and removing using biological metabolism by biological treatment (Japanese Patent Laid-Open No. 7-313994), a method of decomposing and removing urea using a urea-degrading enzyme (Japanese Patent Laid-Open No. 63-20316), etc. Has been done.
II. Known urea adsorbents include oxidized cellulose, a substance obtained by reacting a polymer having a hydrazide group with formaldehyde or glyoxal, and a substance having a carboxyl group and an imidazole group (JP-A-2-221224, JP-A-51-21). -69489, JP 63-59353).
JP-A-7-313994 JP-A-11-99395 JP 63-20316 JP-A-2-221224 JP 51-69489 JP-A-63-59353

i) The devices such as an oxidizer, a decomposer, and a biological treatment device used in a pure water production device are very large, very expensive, and require a large installation area.

  For example, in an ultraviolet oxidation apparatus, urea-like nitrogen compounds are hardly decomposable substances, so that a large number of ultraviolet lamps are required, and the apparatus becomes very large and expensive.

Further, in the case of an ozone oxidation apparatus, it takes time to oxidize hardly decomposed substances, the apparatus becomes large, and the ozone generation apparatus necessary for oxidation becomes large, and the equipment is expensive.
ii) Urea removal described in Patent Documents 4 to 6 is intended for artificial dialysis of kidney disease patients, and the urea concentration in the water to be treated is as high as about 100 mg / dl. It is not intended to remove urea from dilute solutions such as
iii) The present invention solves the above-mentioned problems of the prior art, and is provided with a pure unit equipped with a means capable of sufficiently removing urea-like nitrogen compounds from the treated water having a dilute urea-like nitrogen compound concentration with relatively simple equipment. An object is to provide a water production apparatus.

The pure water production apparatus of the present invention is a pure water production apparatus having an ultraviolet oxidation device that irradiates ultraviolet rays to the water to be treated. The water to be treated contains a urea-like nitrogen compound, and the front or rear stage of the ultraviolet oxidation device. Is a pure water production apparatus provided with a urea-like nitrogen compound adsorbing means having a urea-like nitrogen compound adsorbent for adsorbing a urea-like nitrogen compound , wherein the urea-like nitrogen compound is urea, thiourea, sulfonylurea , Allylurea, guanidine, acetylthiourea, and phenylurea, and the adsorbent is made of oxidized cellulose .

As the urea-like nitrogen compounds, urea, thiourea, sulfonylurea, allyl urea, Guanishin acetylthio urea, phenyl urea and the like.

  According to the pure water production apparatus of the present invention, urea-like nitrogen compounds in the water to be treated are efficiently removed by the adsorbent. This pure water production apparatus adsorbs and removes the urea-like nitrogen compound, the configuration of the urea-like nitrogen compound removal equipment is simple, and the equipment cost is low.

  In the case where the urea-like nitrogen compound adsorbing means is arranged at the front stage of the ultraviolet oxidation device, the concentration of the urea-like nitrogen compound flowing into the ultraviolet oxidation device is lowered, and the load on the ultraviolet oxidation device is reduced.

  When the urea-like nitrogen compound adsorbing means is arranged at the rear stage of the ultraviolet oxidation apparatus, urea-like nitrogen compounds that could not be removed by the ultraviolet oxidation apparatus can be adsorbed and removed by the urea-like nitrogen compound adsorption means.

  When the urea-like nitrogen compound adsorption means is installed at the end of the pure water supply pipe to the point of use, only the water that needs urea-like nitrogen compound removal treatment will be urea-like nitrogen compound adsorption removal treatment, The load on the nitrogen compound adsorption means is reduced.

  By making the urea-like nitrogen compound adsorbent into a filter medium shape such as a fiber, granule or pleated membrane, the urea-like nitrogen compound is adsorbed and removed, and fine particles are removed by filtration.

  Hereinafter, embodiments will be described with reference to the drawings.

  The pure water production apparatus of the present invention comprises a urea-like nitrogen compound adsorbing means having a urea-like nitrogen compound adsorbent and an ultraviolet oxidation device, and preferably a pretreatment device as shown in FIGS. DESCRIPTION OF SYMBOLS 1, Reverse osmosis membrane processing apparatus (RO apparatus) 2, Urea-like nitrogen compound adsorption apparatus 3, UV oxidation apparatus 4, Deionization apparatus 5 which consists of an ion exchange apparatus or an electrodeionization apparatus, An ultrafiltration membrane apparatus (UF apparatus) ) Or the like.

  In the pure water production apparatus of FIG. 1, the raw water is treated with the pretreatment device 1 and then subjected to RO treatment, the urea-like nitrogen compound is adsorbed and removed, and then subjected to ultraviolet oxidation treatment, and the TOC component is oxidized and ionized. To do. This ionized decomposition product is removed by the deionizer 5. Fine particles such as minute ion exchange resin pieces contained in the effluent water from the deionizer 5 are removed by a fine particle remover 6 having a UF membrane or the like.

  In FIG. 2, the urea-like nitrogen compound adsorbing device 3 is arranged on the rear stage side of the ultraviolet oxidation device 4, and the same process as in FIG. 1 is performed except that the urea-like nitrogen compound is adsorbed and removed here. .

  In FIG. 3, the urea-like nitrogen compound adsorbing device 3 is arranged on the rear stage side of the UF membrane device 6, and the same process as in FIG. 1 is performed except that the urea-like nitrogen compound is adsorbed and removed here. .

The urea-like nitrogen compound adsorption device 3, those with oxidation cellulose scan by Li Cheng adsorbent is used. Oxidized cellulose is preferably obtained by oxidizing lintercellulose having a degree of polymerization of about 500 to 800, but is not limited thereto .

  These adsorbents are preferably in the form of filter media such as fibrous, granular or pleated membranes. As the fiber, fibers having a diameter of about 1 nm to 100 μm and a length of about 0.1 to 100 mm are suitable. As the particles, those having an average particle diameter of about 0.1 to 0.9 mm are suitable. The particle shape is arbitrary such as a spherical shape, a pellet shape, a powder shape, and a crushed shape. As the pleated film shape, a film thickness of 200 to 800 μm is suitable.

  As the adsorption device 3, an adsorption tower having a packed bed filled with such a filter medium-shaped adsorbent is suitable.

  The adsorbing device 3 may be provided before the ultraviolet oxidizer 4 as shown in FIG. 1, may be provided after the ultraviolet oxidizer 4 as shown in FIG. 2, and as shown in FIG. In addition, it may be provided at the end of the pure water supply pipe to the use point.

  When the adsorption device 3 is provided in front of the ultraviolet oxidizer 4, the concentration of urea-like nitrogen compounds in the inflow water to the ultraviolet oxidizer 4 is reduced, so that the load on the ultraviolet oxidizer 4 is reduced and the ultraviolet oxidizer 4 is reduced. However, a simple configuration is sufficient.

  When the adsorption device 3 is provided downstream of the ultraviolet oxidation device 4, it plays a role of polishing urea-like nitrogen compounds that could not be processed by the ultraviolet oxidation device, and in particular, when it is provided at the end of the water supply pipe, the adsorption device The amount of water to be processed is small, and the amount of adsorbent can be reduced.

  That is, in particular, in pure water manufacturing facilities such as semiconductor manufacturing, ultrapure water is often circulated to supply only a necessary amount at the place of use. In addition, the water quality requirements at the place of use vary, and it is divided into systems that require organic substance removal, systems that do not require organic substance removal, systems that require fine particle removal, and systems that do not require fine particle removal. There are many.

  Therefore, the installation area and cost of the urea-like nitrogen compound adsorbing device can be reduced by installing the urea-like nitrogen compound adsorbing device only in a system that requires advanced organic matter removal.

  As the pretreatment device 1, a membrane filtration device such as a UF membrane device or a microfiltration membrane device is suitable. However, a biological treatment device may be installed in front of these membrane filtration devices.

  Examples of raw water to be treated include city water, well water, industrial water, and recovered water.

  As the RO apparatus 2, a two-stage RO processing apparatus in which the RO apparatuses are installed in two stages in series is suitable.

  As the ultraviolet oxidizer 4, a low-pressure ultraviolet oxidizer or the like is suitable.

  As the deionization device 5, as described above, an electrodeionization device and an ion exchange device are suitable.

  Hereinafter, examples, comparative examples, and reference examples will be described.

In addition, the adsorbent, equipment, and analysis method used in these examples are as follows.
Activated carbon: “Crycol KW10-30” manufactured by Kurita Kogyo Co., Ltd.
Urea-like nitrogen compound adsorbent (oxidized cellulose): manufactured by Johnson & Johnson Co., Ltd.
"Absorbable hemostat" (average diameter 2μm, average length 5mm)
Novolac type phenolic resin adsorbent: PSM-4326 manufactured by Gunei Chemical Industry Co., Ltd.
(Average particle size 0.3mm)
Ion exchange resin column: “Demiace DY-07” manufactured by Kurita Kogyo Co., Ltd.
Ion exchange resin: “KR-UM2” manufactured by Kurita Kogyo Co., Ltd.
UV oxidizer: “KUS-1 Kai” (UV oxidative decomposition lamp) manufactured by Nippon Photo Science Co., Ltd.
(1 special order product)
TOC meter: PPT made by Sievers
Urea analysis method: Diacetyl method

[Reference Examples 1, 2, 3]
As shown in FIG. 5, a closed circulation line was adopted in which the raw water in the raw water tank 10 was passed through the adsorption tower 11 and the ion exchange tower 13 in this order and returned to the raw water tank 10.

  The adsorbent in the adsorption tower 11 was activated carbon (Reference Example 1), oxidized cellulose (2), and phenol resin (3).

  Raw water obtained by adding 0.5 mg / L of urea as a special grade reagent to ultrapure water was used as raw water, and the TOC concentration, urea concentration and resistivity before and after treatment were measured.

The water flow rate was 1 L / hr, and the water flow SV of the adsorption tower 11 was 10 hr ⁻¹ . The results are shown in Table 1.

  As shown in Table 1, when oxidized cellulose or phenol resin is used as the adsorbent, the removal performance of TOC and urea is superior to that when activated carbon is used. Oxidized cellulose is particularly excellent in urea removal ability.

[Comparative Examples 1 and 2 and Example 1]
The line shown in FIG. 4 was constructed by providing a UV oxidation apparatus 12 between the adsorption tower 11 and the ion exchange tower 13. The other conditions were the same as in Reference Example 1, and water was passed through. The results are shown in Table 2.

[Comparative Examples 3 and 4 and Example 2 ]
Water flow rate except that a 2L / hr to the comparative example of the raw water 1, 2, was passing water in Example 1 and the same conditions. The results are shown in Table 3.

For the adsorbent, Comparative Examples 1 and 3 were activated carbon, Examples 1 and 2 were oxidized cellulose, and Comparative Examples 2 and 4 were phenol resins.

As shown in Tables 2 and 3, in Examples 1 and 2 using oxidized cellulose, no increase in TOC and urea was observed even when the flow rate was increased to 2 L / hr. On the other hand, in Comparative Examples 1 and 3 using activated carbon, an increase in TOC and urea was confirmed when the flow rate was increased.

  Thus, even if the flow rate is doubled, the removal efficiency of TOC and urea did not change, so it can be said that the removal performance does not change even if the load of the UV oxidation apparatus is increased. That is, by placing the urea adsorbent in front of the UV oxidizer, the load on the UV oxidizer is reduced, and even if the performance capability of the TOC oxidizer is reduced, the TOC and urea concentration of the treated water are not affected. . That is, by installing the urea adsorption means in front of the UV oxidizer, it is possible to select a UV oxidizer having a low performance, thereby reducing the overall cost.

[Reference Example 4]
Alumina-dispersed raw water was prepared by dispersing 1 mg / L of white alumina No. 2 of JIS Z 8901 Test Powder 2 in the raw water. This alumina-dispersed raw water was passed through an MF filter having a pore diameter of 0.45 μm at a head pressure of 0.1 MPa at a flow rate of 1 L / hr. The quality of this treated water is shown in Table 4.

[Reference Example 5]
A non-woven fabric of oxidized cellulose was packed in a column having a diameter of 30 mm to a height of 150 mm. When this packed column is placed in front of the same MF filter as in Reference Example 4 and the same alumina dispersion raw water as in Reference Example 4 is passed in series from the packed column to the MF filter under the same conditions, water flows up to 400 L through the MF filter. We were able to. Table 4 shows the quality of the treated water at this time.

  As in Reference Examples 4 and 5, the oxidized cellulose non-woven fabric can remove not only the urea-like nitrogen compound adsorbent but also the fine particles. As described above, by using the oxidized cellulose nonwoven fabric having both the filter function and the TOC removal function as the urea-like nitrogen compound adsorbent, the installation area of the apparatus on the rear side of the adsorption apparatus is reduced, the cost is reduced, and maintenance such as replacement is performed. Simplification can be expected.

It is a systematic diagram of the pure water manufacturing apparatus of an Example. It is a systematic diagram of the pure water manufacturing apparatus of another Example. It is a systematic diagram of the pure water manufacturing apparatus of another Example. It is a systematic diagram of the pure water manufacturing apparatus of a reference example. It is a systematic diagram of the pure water manufacturing apparatus of another reference example.

DESCRIPTION OF SYMBOLS 1 Pre-processing apparatus 2 Reverse osmosis membrane processing apparatus 3 Urea-like nitrogen compound adsorption apparatus 4 Ultraviolet oxidation apparatus 5 Deionization apparatus 6 Fine particle removal apparatus

Claims (4)

In a pure water production apparatus having an ultraviolet oxidation device that irradiates ultraviolet rays to water to be treated,
The treated water contains urea-like nitrogen compounds,
A pure water production apparatus provided with a urea-like nitrogen compound adsorbing means having a urea-like nitrogen compound adsorbent adsorbing a urea-like nitrogen compound before or after the ultraviolet oxidation apparatus ,
The urea-like nitrogen compound is any one of urea, thiourea, sulfonylurea, allylurea, guanidine, acetylthiourea, and phenylurea, and the adsorbent is made of oxidized cellulose .   2. The pure water production apparatus according to claim 1, wherein the adsorption means is installed at a terminal of a pure water supply pipe to a use point.   3. The pure water production apparatus according to claim 1, wherein the adsorbent has a filter medium shape.   4. The apparatus for producing pure water according to claim 3, wherein the adsorbent is in the form of fibers, granules, or pleats.

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