JP2019115892A - Toc removal device and toc removal method - Google Patents

Abstract

To provide a TOC removal device and a TOC removal method capable of easily and continuously decomposing and removing TOC including hardly decomposable TOC in TOC-containing water.SOLUTION: In a TOC removal device and a TOC removal method,: adsorption (at supplying oxygen gas-dissolved TOC-containing water) and desorption (at supplying hydrogen gas-dissolved TOC-containing water) of TOC to a catalyst having a TOC decomposition capacity in a continuous electric deionizer can be continuously repeated by alternately switching water supplied to the continuous electric deionizer filled with the catalyst having the TOC decomposition capacity together with an anion exchanger and a cation exchanger to the hydrogen gas-dissolved TOC-containing water and the oxygen gas-dissolved TOC-containing water in the desalting chamber of the continuous electric deionizer; and water treatment is continuously performed by adsorbing TOC decomposition products such as urea and the like ionized at desorption with an ion exchanger in a desalting chamber and continuously reproducing the ion exchanger adsorbed with the TOC decomposition products by the original action of the continuous electric deionizer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a TOC removing apparatus and a TOC removing method, and more particularly, to a TOC removing apparatus and a TOC removing method for resolving and removing TOC including resistant TOC in TOC-containing water more simply and continuously.

  For cleaning and surface treatment of electronic components, a high concentration chemical solution or detergent, and a large amount of pure water or ultrapure water for rinsing it are used. For this reason, not only the improvement of the water quality of ultrapure water accompanying the advancement of electronic parts, but also the improvement of the water recovery rate by waste water recovery aiming to reduce the amount of water used has become an issue. Among them, efficiently reducing the concentration of organic components (TOC) in water to a lower concentration is an important issue in both water quality improvement and water recovery rate improvement.

  Methods of decomposing TOC include biological treatment and physicochemical treatment, and when it is difficult to apply biological treatment, for example, removal with a reverse osmosis (RO) membrane and use in combination with an oxidizing agent among physicochemical treatments Thermal decomposition and low pressure UV oxidizers using low pressure UV lamps have been used.

However, these methods require a large amount of electrical energy (e.g., driving power of RO membrane water supply pressure pump and UV irradiation power) and thermal energy (e.g., steam of thermal decomposition apparatus).
In addition, RO membranes and low-pressure UV oxidizers, which are often used in ultrapure water production systems, etc., are extremely degraded with respect to TOC called persistent TOC, which is represented by nitrogen compounds (such as urea) with small molecular weight. There was also a problem that the efficiency was poor.

With respect to these problems, the inventor of the present invention has proposed a TOC removal method using a catalyst in Patent Document 1.
This method is a method of repeatedly performing the hydrogen water passing step, the oxygen water passing step and the organic substance-containing raw water passing step on the platinum group metal catalyst, and the TOC is decomposed by the following mechanism.
When hydrogen water is passed through a catalyst, hydrogen is adsorbed on the catalyst. By supplying oxygen water while hydrogen is adsorbed to the catalyst, water molecules are formed on the catalyst, and some water molecules remain on the catalyst. Then, when the organic matter-containing water is supplied, the organic matter is adsorbed to the catalyst by binding such a coordination bond between the water molecule and the TOC such as urea having a non-covalent electron pair. The adsorbed organic matter is partially decomposed by the action of the platinum group catalyst. Then, at the time of the next hydrogen water supply, the hydrogen adsorbs to the catalyst and at the same time the decomposition product leaves the catalyst.
By contacting the treated water after contacting with the catalyst in this manner with at least one of the anion exchange resin and the cation exchange resin, the ion exchange resin adsorbs and removes ionic substances such as organic acids generated by the decomposition of TOC. it can. For this reason, in patent document 1, the ion exchange resin column is provided in the back | latter stage of a catalyst packed column.

The continuous electrodeionization apparatus used in the present invention is a deionized water used in various industries such as a semiconductor manufacturing plant, a liquid crystal manufacturing plant, a pharmaceutical industry, a food industry, an electric power industry, or for household use or research facilities. It is widely used in manufacturing. In the continuous electrodeionization apparatus, as shown in FIG. 2, a concentration chamber 15 and a deionization chamber 16 are alternately arranged with a plurality of anion exchange membranes 13 and cation exchange membranes 14 between electrodes (anode 11 and cathode 12). Are alternately formed, and the deionization chamber 16 is filled with an anion exchanger composed of ion exchange resin, ion exchange fiber, graft exchanger, etc. and a cation exchanger in a mixed or multi-layered form. In FIG. 2, 17 is an anode chamber and 18 is a cathode chamber.
Continuous electrodeionization apparatus, by dissociation of water H ⁺ ions and OH ^- to produce ions, by continuously reproducing ion exchanger filled in the desalting compartment, efficient deionization can It has an excellent feature that complete continuous water sampling is possible and high purity water can be obtained without requiring regeneration treatment using chemicals such as ion exchange resin devices which have been widely used conventionally. .

JP, 2013-208557, A

  In the method of Patent Document 1, it is necessary to switch between the hydrogen water flow process, the oxygen water flow process, and the raw water flow process, which causes problems such as pressure fluctuation. In addition, when the ionic substance generated by the treatment of the raw water is adsorbed to the ion exchange resin and removed, the exchange and regeneration operation of the ion exchange resin are required, and there is a problem in the continuous processability.

  An object of the present invention is to provide a TOC removing apparatus and a TOC removing method capable of decomposing and removing TOC in TOC-containing water more easily and continuously, including persistent TOC.

As a result of intensive studies to solve the above problems, the present inventors have filled the deionization chamber of a continuous electrodeionization apparatus with an anion exchanger and a cation exchanger together with a catalyst having TOC resolution. It has been found that TOC can be easily and continuously decomposed and removed, including resistant TOC, without the need for switching water flow and exchanging or regenerating ion exchange resin.
That is, the deionization chamber of the continuous electrodeionization apparatus is filled with an anion exchanger and a cation exchanger together with a catalyst having TOC resolution, and the water supplied to the continuous electrodeionization apparatus is water containing hydrogen gas dissolved TOC and oxygen By alternately switching with gas solution TOC containing water, TOC is adsorbed (at the time of water supply with oxygen gas dissolved TOC containing water) to the catalyst having TOC resolution in the continuous electrodeionization apparatus, desorption (hydrogen gas dissolved TOC containing water supply) Time) can be continuously repeated, and desorbed TOC decomposition products such as ionized urea at the time of desorption are adsorbed by the ion exchanger in the deionization chamber, and the ion exchanger adsorbed the TOC decomposition products is continuously electrodeionized. By continuously regenerating by the original action of the device, it becomes possible to perform water treatment continuously.

  The present invention has been achieved based on such findings, and the present invention provides the following.

[1] A TOC removing device characterized by having a continuous electrodeionization device containing a catalyst having TOC resolution in a deionization chamber.

[2] A gas dissolving means for dissolving hydrogen gas or oxygen gas in TOC containing water, TOC containing water in which hydrogen gas is dissolved in the gas dissolving means, and TOC containing water in which oxygen gas is dissolved The TOC removing device according to [1], further comprising: means for introducing alternately into the deionization chamber of the deionizing device.

[3] A gas dissolution membrane module in which the gas dissolution means is provided at a front stage of the continuous electrodeionization apparatus, hydrogen gas supply means for supplying hydrogen gas to the gas phase chamber of the gas dissolution membrane module, and the gas The oxygen gas supply means for supplying oxygen gas to the phase chamber, the switching means for alternately switching the gas supply by the hydrogen gas supply means and the oxygen gas supply means, the TOC containing water in the liquid phase chamber of the gas dissolution membrane module And means for supplying water, wherein the gas-dissolved TOC-containing water flowing out of the liquid phase chamber is introduced into the deionization chamber of the continuous electrodeionization apparatus [2]. apparatus.

[4] Oxygen gas feed means for feeding the oxygen gas generated at the anode of the continuous electrodeionization apparatus to the gas dissolving means as oxygen gas for dissolving in the TOC-containing water, and / or the continuous electricity A hydrogen gas delivery means is provided for feeding the hydrogen gas generated at the cathode of the deionization apparatus to the gas dissolving means as the hydrogen gas for dissolving the TOC-containing water as described in [2] or [3]. TOC remover.

[5] The TOC removal apparatus according to any one of [1] to [4], wherein the catalyst having TOC resolution is made of fine particles of a platinum group metal and supported on an ion exchange resin.

[6] A deionization chamber of the continuous electrodeionization apparatus is filled with a cation exchange resin and an anion exchange resin on which a metal having TOC resolution is supported. The TOC removal apparatus in any one of 5].

[7] A method for decomposing and removing TOC in TOC-containing water, comprising a hydrogen gas dissolution step of dissolving hydrogen gas in the TOC-containing water, and an oxygen gas dissolution step of dissolving oxygen gas in the TOC-containing water, In the deionization chamber of the TOC removal apparatus according to any one of [1] to [6], hydrogen gas-dissolved TOC-containing water from the hydrogen gas-dissolving step and oxygen gas-dissolved TOC-containing water from the oxygen gas-dissolving step And alternately introducing and decomposing and removing TOC in the TOC-containing water.

  According to the present invention, it becomes possible to decompose and remove TOC more easily and continuously, including the persistent TOC in TOC-containing water.

It is a systematic diagram showing an embodiment of TOC removal device of the present invention. FIG. 1 is a schematic cross-sectional view showing a general configuration of a continuous electrodeionization apparatus.

  Hereinafter, embodiments of the TOC removing apparatus and the TOC removing method of the present invention will be described in detail.

The TOC removal apparatus of the present invention is a continuous electrodeionization apparatus (hereinafter referred to as "the continuous electrodeionization apparatus according to the present invention") comprising a desalting chamber filled with an anion exchanger and a cation exchanger together with a catalyst having TOC resolution. In some cases, and may be referred to as
The member configuration itself of the continuous electrodeionization device of the present invention is the same as the general continuous electrodeionization device shown in FIG. 2, and the continuous electrodeionization device of the present invention is a continuous electrodeionization device. The desalting chamber of the catalyst is filled with a catalyst having TOC resolution.

As described above, in the continuous electrodeionization apparatus, as shown in FIG. 2, a plurality of anion exchange membranes 13 and cation exchange membranes 14 are alternately arranged between the electrodes (anode 11 and cathode 12) to form a concentration chamber 15 The deionization compartments 16 are alternately formed, and the deionization compartments 16 are filled with an anion exchanger composed of ion exchange resin, ion exchange fiber, graft exchanger or the like and a cation exchanger in a mixed or multilayered form.
The continuous electrodeionization apparatus of the present invention comprises an anion exchanger and a cation exchanger together with a catalyst having TOC resolution in the deionization chamber of such a general continuous electrodeionization apparatus. , As its filling method,
(1) A part of the plurality of desalting compartments is filled with a catalyst having TOC resolution, and the other desalting compartments are filled with anion exchangers and cation exchangers.
(2) A part of the plurality of desalting compartments is filled with a catalyst having TOC resolution, an anion exchanger and a cation exchanger, and the other desalting compartments are filled with an anion exchanger and a cation exchanger.
(3) All demineralization chambers are filled with a catalyst having TOC resolution, an anion exchanger and a cation exchanger.
Although methods such as the above can be considered, since TOC of the treated water not in contact with the catalyst having TOC resolution is not decomposed, it is preferable to load the catalyst having TOC resolution by the method of (3).

The catalyst having TOC resolution is not particularly limited as long as it has TOC resolution, but it is preferable to use a platinum group metal catalyst because it is also excellent in non-degradable TOC resolution.
As a platinum group metal used for a catalyst, ruthenium, rhodium, palladium, osmium, iridium and platinum can be mentioned. These platinum group metals can be used alone or in combination of two or more, or as an alloy of two or more, or the purity of a naturally produced mixture. It can also be used without separating the product into single components. Among these, platinum, palladium, platinum / palladium alloy alone or a mixture of two or more of them can be particularly preferably used because they have strong catalytic activity.

  The platinum group metal catalyst may be platinum group metal fine particles, or may be a metal supported catalyst in which platinum group metal nanocolloid particles are supported on the surface of a support.

  The average particle size of the platinum group metal nanocolloid particles is preferably 1 to 50 nm, more preferably 1.2 to 20 nm, and still more preferably 1.4 to 5 nm. If the average particle size of the metal nanocolloid particles is less than 1 nm, the catalyst activity for the decomposition and removal of TOC may be reduced. If the average particle size of the metal nanocolloid particles exceeds 50 nm, the specific surface area of the nanocolloid particles may be reduced, and the catalytic activity for the decomposition and removal of TOC may be reduced.

  There is no restriction | limiting in particular in the support | carrier which carry | supports platinum group metal nanocolloid particle | grains, For example, magnesia, a titania, an alumina, a silica-alumina, a zirconia, activated carbon, a zeolite, diatomaceous earth, ion exchange resin etc. can be mentioned. Among these, anion exchange resins can be particularly preferably used. Since platinum group metal nanocolloid particles have an electric double layer and are negatively charged, they are stably supported on an anion exchange resin and hardly exfoliate. The anion exchange resin is preferably a strongly basic anion exchange resin based on a styrene-divinylbenzene copolymer, and more preferably a gel-type resin. Moreover, it is preferable that the exchange group of anion exchange resin is OH form.

  The loading amount of the platinum group metal nanocolloid particles on the anion exchange resin is preferably 0.01 to 0.2% by weight, and more preferably 0.04 to 0.1% by weight. If the loading amount of the metal nanocolloidal particles is less than 0.01% by weight, there is a possibility that the catalytic activity for the decomposition and removal of TOC may be insufficient. The loading amount of the metal nanocolloid particles is 0.2 wt% or less, sufficient catalytic activity for decomposing and removing TOC is developed, and it is not usually necessary to support the metal nanocolloid particles exceeding 0.2 wt%. In addition, when the loading amount of metal nanocolloidal particles is increased, the possibility of metal elution in water also increases.

  The loading amount of the catalyst having TOC resolution into the demineralization chamber is not particularly limited, and is appropriately adjusted according to the required TOC resolution.

  Examples of the anion exchanger and cation exchanger packed in the deionization chamber of the continuous electrodeionization apparatus of the present invention include ion exchange resin, ion exchange fiber, graft exchanger and the like, preferably anion exchange resin And cation exchange resin.

  There are no particular limitations on the filling ratio of the anion exchanger and the cation exchanger in the demineralization chamber, but in general, anion exchanger: cation exchanger = 1: 1 to 7: 3 (volume ratio).

  As described above, since it is preferable to use a platinum group metal catalyst supported on an anion exchange resin as the catalyst having TOC resolution, as the continuous electrodeionization apparatus of the present invention, anion exchange in the demineralization chamber is preferable. Using a resin filled with the above-mentioned platinum group metal-supported anion exchange resin in place of a conventional ordinary anion exchange resin as a resin can sufficiently charge a catalyst having TOC decomposability, and additionally, it can be used as a platinum group metal. This is a preferred embodiment because the loading of the catalyst having TOC resolution and the loading of the anion exchanger can be performed only by loading the metal-supported anion exchange resin.

  In this case, since the loading of the catalyst having TOC decomposition occurs only on the surface, the anion exchange capacity inside the anion exchange resin remains. Therefore, even when the anion exchange resin packed in the deionization chamber of the continuous electrodeionization apparatus is the above metal catalyst-supported anion exchange resin, the ion exchange capacity is not impaired.

  In the continuous electrodeionization apparatus of the present invention, the concentration chamber may also be filled with an anion exchanger and a cation exchanger.

As described in Patent Document 1, the decomposition of TOC by the catalyst having TOC decomposition needs to be previously supplied with hydrogen and then supplied with oxygen.
Therefore, in the TOC removal apparatus of the present invention, a gas dissolving means for dissolving hydrogen gas or oxygen gas in TOC containing water which is raw water, and TOC containing water and hydrogen gas in which hydrogen gas is dissolved by the gas dissolving means It is preferable to provide means for alternately introducing the TOC-containing water into the deionization chamber of the continuous electrodeionization apparatus of the present invention. As the gas dissolution means, a gas dissolution membrane module is provided at the front stage of the continuous electrodeionization apparatus, and hydrogen gas supply means for supplying hydrogen gas to the gas phase chamber of the gas dissolution membrane module and oxygen gas supply means for supplying oxygen gas And switching means for alternately switching the gas supply by the hydrogen gas supply means and the oxygen gas supply means, and means for supplying TOC-containing water to the liquid phase chamber of the gas dissolution membrane module; It is preferable to introduce the gas-dissolved TOC-containing water flowing out of the chamber into the deionization chamber of the continuous electrodeionization apparatus.
As described above, in the method of Patent Document 1, it is necessary to repeat the hydrogen water passing step, the oxygen water passing step and the organic substance-containing raw water passing step repeatedly, whereas in the present invention, the hydrogen gas and the oxygen gas are used. Since it is possible to alternately supply hydrogen water and oxygen water by switching, the TOC can be decomposed and removed by alternately passing water containing hydrogen gas dissolved TOC and water containing oxygen gas dissolved TOC.

  Further, in the continuous electrodeionization apparatus, since a DC voltage is applied to water, oxygen is generated at the anode and hydrogen is generated at the cathode. Therefore, the oxygen gas generated at the anode is dissolved in TOC-containing water of the raw water It is preferable to supply hydrogen gas generated at the cathode as a gas to hydrogen gas dissolving means such as a gas dissolving membrane module as hydrogen gas to dissolve in TOC-containing water of raw water for effective use.

FIG. 1 is a system diagram showing an embodiment of the TOC removing apparatus of the present invention incorporating such a preferred embodiment.
The TOC removal device for raw water is supplied to the gas dissolving membrane module 1 which is a gas dissolving means through the raw water supply pipe L1. The gas dissolving means is not limited as long as it can dissolve gas in TOC-containing water, and a membrane, ejector, aeration mechanism, etc. may be used. Here, the gas dissolving membrane module 1 which is easy to handle is illustrated. Raw water is appropriately dissolved in nitrogen gas and hydrogen gas or oxygen gas in the gas dissolving membrane module 1, and it passes through the water supply pipe L2 as gas dissolving water from the liquid phase chamber 1B of the gas dissolving membrane module 1, and continuous electrodeionization is carried out. It is supplied to the device 2. The nitrogen gas in the nitrogen gas tank 3 is supplied as a carrier gas to the gas phase chamber 1A of the gas dissolution membrane module 1 through a nitrogen gas pipe L3 having a nitrogen gas flow rate adjustment valve V1 and a gas supply main pipe L6. The nitrogen gas is preferably supplied at about 10 to 1000 NL / min depending on the type of membrane of the gas dissolving membrane module 1, but it is not limited because it depends on the amount of water and the number of membranes. Nitrogen gas supply means dilution because hydrogen gas is explosive, but it is not limited as long as explosion proof measures are taken.

  The hydrogen gas in the hydrogen gas tank 5 is 0.1 to 4.0% by volume, for example, about 1% by volume, of the nitrogen gas flow rate, and is supplied via the hydrogen gas line L5 having the hydrogen gas flow rate adjustment valve V3 and the gas supply main line L6. It is supplied to the gas phase chamber 1A of the dissolution membrane module 1. The hydrogen gas supply rate is preferably about 1% by volume of the nitrogen gas flow for safety reasons because the explosion limit of the hydrogen gas is 4% by volume or more of the nitrogen gas flow, but as described above, explosion proof measures are taken If it is, it is not the limit.

  The oxygen gas in the oxygen gas tank 4 is supplied to the gas phase chamber 1A of the gas dissolution membrane module 1 through the oxygen gas pipe L4 having the oxygen gas flow rate adjustment valve V2 and the gas supply main pipe L6. Similarly to hydrogen gas, the supply amount of oxygen gas is preferably 0.1 to 20% by volume of nitrogen gas flow rate, for example, about 1% by volume, which is sufficient. L 7 is an exhaust pipe from the gas phase chamber 1 A of the gas dissolving membrane module 1.

Thus, hydrogen gas and oxygen gas are alternately supplied together with nitrogen gas as a carrier gas to supply hydrogen to the continuous electrodeionization apparatus 2 → hydrogen gas dissolving raw water → oxygen gas dissolving raw water → hydrogen gas dissolving gas → oxygen The catalyst in the deionization chamber of the continuous electrodeionization apparatus 2 can adsorb and desorb TOC by alternately repeating the gas-dissolved raw water.
In addition, about 1/2 TOC is ionized during desorption, but the generated ionized decomposition product is repeatedly absorbed and desorbed by continuous water passage, whereby the ion exchanger in the deionization chamber of the continuous electrodeionization apparatus 2 is repeated. And is discharged out of the system through the concentration chamber of the continuous electrodeionization device 2.

Here, the mechanism by which TOC adsorbs and desorbs to a catalyst having TOC resolution is as follows.
First, when hydrogen gas-dissolved water is supplied to the metal catalyst, hydrogen is stored in the catalyst, and a weak bond between the catalyst metal and hydrogen is generated on the surface. When a coexistence system of oxygen gas and TOC comes into contact with the metal catalyst in that state, when hydrogen atoms and oxygen atoms present on the surface of the catalyst metal combine, electrons in the oxygen atoms are pulled in the hydrogen (metal) direction It is thought that there is a deficiency, and the non-covalent electron pair of TOC bonds with it. In this state, when hydrogen gas-dissolved water is brought into contact again, desorption from oxygen atoms occurs, and it is believed that part of TOC is ionized and detached. Therefore, it is necessary to make hydrogen gas dissolved water and oxygen gas dissolved water alternately contact the metal catalyst, but it can be coped with by switching the gas supply to the gas dissolving means with oxygen gas and hydrogen gas as described above. It is not necessary to switch the water flow path, and it is possible to easily cope with the pressure fluctuation and the like. In this case, the timing of switching the gas alternately is preferably about 1 to 600 seconds, particularly preferably about 10 to 300 seconds, and the oxygen gas supply time is about 0.5 to 2.0 times the hydrogen gas supply time. Is preferred.

  In the demineralization chamber of the continuous electrodeionization apparatus 2, hydrogen gas-dissolved raw water is firstly supplied. The TOC in the hydrogen gas-dissolved raw water supplied here flows out as it is because oxygen does not exist, but it is desirable to initially blow the treated water obtained by this initial water supply. Moreover, when hydrogen gas dissolving raw water and oxygen gas dissolving raw water are alternately repeated, TOC of the feed water of hydrogen gas dissolving raw water passes through the resin layer to which oxygen was adsorbed, and absorption and desorption occur instantaneously without problems. It is processed.

  Thus, the TOC in the raw water is decomposed by the continuous electrodeionization apparatus 1, and the ionic substance produced by the decomposition is removed by the ion exchange with the ion exchanger in the deionization chamber, and the treated water is continuously electricity. It is discharged out of the system from the treated water discharge pipe L8 of the deionization device 1.

  As described above, in the continuous electrodeionization apparatus 2, since a DC voltage is applied to water, oxygen gas is generated at the anode and hydrogen gas is generated at the cathode respectively, so oxygen gas generated at the anode is dissolved in raw water In order to effectively use the hydrogen gas generated at the cathode as hydrogen gas to be dissolved in the raw water, the oxygen gas generated at the anode of the continuous electrodeionization device 2 is used as the oxygen gas exhaust pipe L9 in the TOC removal device of FIG. The hydrogen gas generated at the cathode is supplied to the hydrogen gas tank 5 through the hydrogen gas exhaust pipe L10. L11 and L12 are pipes for exhausting the respective gases out of the system.

  According to such a TOC removing apparatus of the present invention, TOC in TOC-containing water can be simply and continuously processed to be highly decomposed and removed, including persistent TOC. In particular, the present invention is suitable as a system for further reducing the concentration of TOC components in ultrapure water having a TOC concentration of about 1 to 10 ppb.

  Hereinafter, the present invention will be more specifically described by way of examples and comparative examples.

In each of the following examples and comparative examples, treatment was performed at a flow rate of 1 m ³ / hr using TOC-containing water having a TOC concentration of 3 ppb containing urea as a TOC source as raw water.

Example 1
Raw water was treated by the TOC removal device of the present invention shown in FIG.
The specifications of the device used for the test are as follows.
Gas dissolution membrane module: "Liquidelle G284" (4 x 28 inches) manufactured by Celgard
Continuous electrodeionization apparatus: "KCDI" manufactured by Kurita Kogyo Co., Ltd.
Filling resin in the deionization chamber of the continuous electrodeionization apparatus:
Anion exchange resin: "Nano Saber" manufactured by Kurita Kogyo Co., Ltd.
(Platinum nanocolloid carrier anion exchange resin) 10 L
Cation exchange resin: Kurita Kogyo Co., Ltd. "KR-UC1" 10 L

  The nitrogen gas flow rate is constant at 10 NL / min, the hydrogen gas flow rate is 0.1 NL / min, the oxygen gas flow rate is 0.5 NL / min, hydrogen gas is supplied for 30 seconds, oxygen gas is for 60 seconds, and hydrogen gas and oxygen gas are supplied. The supply was switched alternately.

  As a result, the TOC concentration of the treated water of the continuous electrodeionization apparatus was 1 ppb or less, and the TOC could be highly decomposed and removed in the continuous operation.

Comparative Example 1
Raw water is treated with a low pressure ultraviolet lamp device ("AZ-26" manufactured by Japan Photo Science Co., Ltd.), and an ion exchange resin column (mixed resin of "KR-UA1" and "KR-UC1" manufactured by Kurita Kogyo Co., Ltd.) After treatment, the TOC concentration of the treated water was 3 ppb, and it was not decomposed at all because urea was the main component.

Comparative Example 2
The raw water was treated by the method described in Patent Document 1. That is, instead of the continuous electrodeionization apparatus, a catalyst column packed with "Nanosaber" (platinum nanocolloid carrier anion exchange resin) manufactured by Kurita Kogyo Co., Ltd. is used, followed by an ion exchange resin column (Kurita Kogyo Co., Ltd. A mixed resin of “KR-UA1” and “KR-UC1” manufactured by A.K.
As a result, the TOC concentration of the treated water of the ion exchange resin column was 1 ppb or less, but when switching the catalyst column from hydrogen treatment to oxygen treatment, pressure fluctuation of about 10 kPa occurred and continuous treatment could not be performed. Further, the adsorption amount of the ion exchange resin was broken in about 20 days, and resin exchange was required, and continuous processing could not be performed.

Reference Signs List 1 gas dissolving membrane module 2 continuous electrodeionization device 10 ion exchanger 11 anode 12 cathode 13 anion exchange membrane 14 cation exchange membrane 15 concentration chamber 16 deionization chamber 17 anode chamber 18 cathode chamber

Claims (7)

  A TOC removal apparatus comprising a continuous electrodeionization apparatus including a catalyst having TOC resolution in a deionization chamber. Gas dissolving means for dissolving hydrogen gas or oxygen gas in TOC-containing water;
Means for alternately introducing TOC-containing water in which hydrogen gas is dissolved by the gas dissolution means and TOC-containing water in which oxygen gas is dissolved into the deionization chamber of the continuous electrodeionization apparatus The TOC removal apparatus according to claim 1, wherein   In the gas dissolving membrane module in which the gas dissolving means is provided at the front stage of the continuous electrodeionization apparatus, hydrogen gas supplying means for supplying hydrogen gas to the gas phase chamber of the gas dissolving membrane module, and Oxygen gas supply means for supplying oxygen gas, switching means for alternately switching the supply of gas by the hydrogen gas supply means and the oxygen gas supply means, and the TOC-containing water is supplied to the liquid phase chamber of the gas dissolution membrane module 3. The TOC removing device according to claim 2, further comprising: a gas-dissolving TOC-containing water flowing out of the liquid phase chamber is introduced into the deionization chamber of the continuous electrodeionization device.   Oxygen gas feed means for feeding oxygen gas generated at the anode of the continuous electrodeionization device to the gas dissolving means as oxygen gas for dissolving the TOC-containing water, and / or the continuous electrodeionization device 4. The TOC removing device according to claim 2, further comprising: a hydrogen gas delivery unit for feeding the hydrogen gas generated at the cathode of the cathode to the gas dissolving unit as the hydrogen gas for dissolving the TOC-containing water.   The TOC removing apparatus according to any one of claims 1 to 4, wherein the catalyst having TOC resolution is made of fine particles of a platinum group metal and supported on an ion exchange resin.   The deionization chamber of the continuous electrodeionization apparatus is filled with a cation exchange resin and an anion exchange resin on which a metal having a TOC resolution is supported. The TOC removing device according to item 1.   A method of decomposing and removing TOC in TOC-containing water, comprising: a hydrogen gas dissolving step of dissolving hydrogen gas in the TOC-containing water; and an oxygen gas dissolving step of dissolving an oxygen gas in the TOC-containing water, The water containing hydrogen gas dissolved TOC from the hydrogen gas dissolving step and the water containing oxygen gas dissolved TOC from the oxygen gas dissolved step alternately from the hydrogen gas dissolving step are alternately inserted into the deionization chamber of the TOC removal apparatus according to any one of And decomposing and removing the TOC in the TOC-containing water.

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