JP4855068B2 - Electric deionized water production apparatus and deionized water production method - Google Patents

Description

  The present invention is used in various fields such as semiconductor manufacturing field, pharmaceutical manufacturing field, power generation field such as nuclear power and thermal power, food industry, etc. The present invention relates to an electric deionized water production apparatus that prevents scale generation.

  A conventional electric deionized water production apparatus has a plurality of demineralization chambers and concentration chambers alternately arranged between an anode chamber having an anode and a cathode chamber having a cathode. There is a problem that the electric resistance is large and the applied voltage between the two electrodes becomes high. In addition, there is a problem that calcium carbonate scale caused by calcium ions and carbonic acid components in the water to be treated is generated in the ion exchange membrane in the concentration chamber.

  As a solution to this problem, Japanese Patent Application Laid-Open No. 2003-136063 discloses that one cation exchange membrane and one anion exchange membrane are arranged between the cathode and the anode, and the cation exchange membrane is concentrated between the cathode and the cation exchange membrane. A chamber / cathode chamber is provided, a concentration chamber / anode chamber is provided between the anode and the anion exchange membrane, and a desalting chamber is provided between the cation exchange membrane and the anion exchange membrane. An electric deionization apparatus is disclosed in which an anode chamber and a concentration chamber / cathode chamber are filled with a conductor such as a cation exchanger, and an ion exchanger is filled in the demineralization chamber. This electric deionized water device is suitable when the amount of produced water is small, the applied voltage between the electrodes is low, and scale is unlikely to occur.

  However, among such electric deionized water devices, for example, those in which the anode chamber and the cathode chamber are filled with cation exchangers, respectively, increase the applied current and increase the ion exclusion efficiency, and anion exchange that allows permeation of anions. There is a problem that the current density cannot be increased because the film burns black, so-called film burning, and the function of transmitting anions is impaired. In addition, the electric deionized water device described in Japanese Patent Application Laid-Open No. 2003-136063 removes both cations and anions in the water to be treated. For example, when removing only cations in the water to be treated and leaving anions, There is a problem that it cannot be applied to cases where it is desired to remove only anions in the water to be treated and leave cations. As an apparatus that removes only cations in the water to be treated and leaves anions, for example, in the analysis of water in the condensate circulation system of a power plant that contains trace amounts of ammonia, hydrazine, or seawater, ammonianium ions, hydrazinium ions, An apparatus for removing cation components such as sodium ions in NaCl of seawater is mentioned. The decationized water flowing out from the apparatus is supplied to a measuring instrument in order to measure the specific resistance or acid conductivity due to HCl contained therein.

  As a device for detecting anions in the water of the condensate circulation system of the power plant, a dealkalization chamber partitioned by two cation exchange membranes and filled with a cation exchanger is disposed between the anode chamber and the cathode chamber, In the anode chamber, the cathode chamber, and the deionization chamber, a water introduction path and a treated water discharge path are arranged, respectively, and the conductivity of the treated water is measured in the treated water discharge path from the dealkalization chamber. A device with a vessel has already been proposed. However, the water in the condensate circulation system contains iron oxides, hydroxides, and various metal ions called clads, and the dealkalization chamber is loaded with clads and metal ions, and the cation exchanger is strongly acidic. The clad contacts and deposits with the cation exchanger in the dealkalization chamber, gradually ionizes, becomes metal ions, permeates the cation exchange membrane, and is removed from the dealkalization chamber to the cathode chamber. The excluded metal ions are locally concentrated on the surface of the cation exchange membrane in the cathode chamber, and react with the hydroxide ions generated by electrolysis of the cathode water to produce a hydroxide scale. In addition, iron hydroxide changes its form with insulating iron oxide by dehydration. When such a scale occurs, there is a problem that the electrical resistance rises at that portion and current does not flow easily.

  Moreover, when the hardness of the to-be-processed water which flows in is high, there exists a problem that scales, such as a calcium carbonate and magnesium hydroxide, generate | occur | produce in the electrode chamber of an electrical deionized water manufacturing apparatus. In other words, calcium ions and magnesium ions that have passed through the cation exchange membrane and have been excluded from the deionization chamber to the cathode chamber are locally concentrated on the surface of the cation exchange membrane in the cathode chamber, and electrolysis of the water in the cathode chamber There is a problem that scale is generated by mixing with the generated hydroxide ions at a concentration exceeding the solubility product. Further, even in the above-described apparatus for detecting anions in water, the problem of burning of the cation exchange membrane has not been solved, and the applied current cannot be increased.

  Therefore, an object of the present invention is to provide an electric deionization that can prevent generation of scales such as iron oxide, iron hydroxide, or a hardness component, even when the applied current is increased, without causing film burning of the ion exchange membrane. It is providing the water manufacturing apparatus and the deionized water manufacturing method.

  Under such circumstances, the present inventors have conducted intensive studies, and as a result, (1) the potential of the potential on the membrane surface facing the cathode of the cation exchange membrane on the cathode side or the membrane surface facing the anode of the anion exchange membrane on the anode side is Since the gradient is steep, it is easy to generate heat. (2) In the electrode chamber, an ion exchanger having the same polarity as the ion exchange membrane, that is, in the case of a cation exchange membrane, a cation exchanger, an anion exchange membrane. In this case, if the anion exchanger is filled, the potential gradient does not occur on the membrane surface and it is difficult to generate heat. (3) In the case of the decationized water production apparatus, the decationized water is removed by the cation exchanger filled in the cathode chamber. Since the metal ions that have moved from the cation chamber to the cathode chamber are excluded as electrode water as they are, it has been found that no scale is generated, and the present invention has been completed.

That is , the present invention provides a decation chamber between the anode chamber and the cathode chamber, which is partitioned by two cation exchange membranes and filled with a cation exchanger adjacent to the anode chamber and the cathode chamber, In the anode chamber and the cathode chamber, an electrode water inflow pipe and an electrode water outflow pipe are provided, and in the decation chamber, a treated water inflow pipe and a treated water outflow pipe are provided, and the cathode and the cation exchange membrane are provided. An electric deionized water production apparatus (second apparatus) is provided in which the cathode chamber to be partitioned is filled with a cation exchanger. The said 2nd apparatus removes the cation in to-be-processed water, and does not remove an anion. In the second apparatus, since the membrane surface on the cathode side of the cation exchange membrane is in contact with the cation exchanger, the potential gradient hardly occurs on the membrane surface, and the cation exchange membrane does not burn. In addition, since the metal ions and hardness components that have moved from the decation chamber to the cathode chamber are excluded as electrode water, they do not generate scale.

  The present invention further includes a deanion chamber that is partitioned between two anion exchange membranes and is filled with an anion exchanger adjacent to the anode chamber and the cathode chamber between the anode chamber and the cathode chamber, In the anode chamber and the cathode chamber, an electrode water inflow pipe and an electrode water outflow pipe are arranged, and in the deanion chamber, a to-be-treated water inflow pipe and a treated water outflow pipe are arranged, and the anode and the anion exchange membrane An anode chamber to be partitioned is filled with an anion exchanger, and an electric deionized water production apparatus is provided. The said 3rd apparatus removes the anion in to-be-processed water, and does not remove a cation. In the third apparatus, since the membrane surface on the anode side of the anion exchange membrane is in contact with the anion exchanger, the potential gradient hardly occurs on the membrane surface, and the anion exchange membrane is not burnt.

  In the present invention, a decation chamber is provided between the anode chamber and the cathode chamber, which is partitioned by two cation exchange membranes and filled with a cation exchanger adjacent to the anode chamber and the cathode chamber. In an electric deionized water production apparatus filled with a cation exchanger, the water to be treated flows into the decation chamber while applying a voltage between the anode and the cathode. The present invention provides a method for producing deionized water, characterized in that electrode water is allowed to flow into an anode chamber and a cathode chamber to remove impurity cations in water to be treated to obtain decationized water.

  In the present invention, a deanion chamber, which is partitioned by two anion exchange membranes and is filled with an anion exchanger adjacent to the anode chamber and the cathode chamber, is disposed between the anode chamber and the cathode chamber. In the electric deionized water production apparatus filled with an anion exchanger, the water to be treated flows into the deanion chamber while applying a voltage between the anode and the cathode. The present invention provides a method for producing deionized water, characterized in that electrode water is caused to flow into an anode chamber and a cathode chamber to remove impurity anions in water to be treated to obtain deanion water.

According to the present invention, in the membrane surface facing the cathode of the cation exchange membrane on the cathode side or the membrane surface facing the anode of the anion exchange membrane on the anode side, the member in contact with the membrane surface is an ion exchanger of the same ionic species. Therefore, the potential gradient is relaxed and film burning does not occur. For this reason, a current density can be raised and ion removal efficiency improves. The current density of the conventional electric deionized water production apparatus was at most 0.1 A / dm ² , but in the present invention, it could be increased to 1.0 A / dm ² . Further, in the case of a decationized water production apparatus that forms a desalination chamber filled with a cation exchanger with two cation exchangers, the metal ions and hardness components that have moved from the decation chamber to the cathode chamber remain as electrode water. Does not generate a scale. For this reason, pretreatment for removing hardness components such as calcium ions and magnesium ions from the water to be treated, that is, softening treatment to exchange hardness components with sodium by passing water through the Na-type cation exchange resin layer, No primary desalination treatment by osmosis membrane or ion exchange is required. Moreover, the electric deionized water production apparatus of the present invention can be miniaturized such that the height and width are each 10 mm or less, and is suitable for applications where the treatment flow rate is as low as several ml to several tens ml / h. It is.

  In the electric deionized water production apparatus of the present invention, the ion exchanger filled in the deionization chamber is not particularly limited, and is a monolithic organic porous ion exchanger (hereinafter also simply referred to as “monolith”), Examples thereof include ion exchange resins and mixtures of monoliths and ion exchange resins. The monolith is not particularly limited and includes those described in JP-A No. 2003-334560, which has an open-cell structure having macropores connected to each other and mesopores having an average diameter of 1-1000 μm in the walls of the macropores. A three-dimensional network structure having a total pore volume of 1 ml / g to 50 ml / g, an ion exchange group uniformly distributed, and an ion exchange capacity of 0.5 mg equivalent / g or more of a dry porous body is used. it can. The ion exchange resin is not particularly limited, and examples thereof include known granular ion exchange resins used for water treatment.

  The mixture of the monolith and the ion exchange resin is not particularly limited, and examples thereof include a layered body in which the monolith phase and the ion exchange resin phase are laminated in the direction in which the discharged ions migrate. The layered body of monolith and ion exchange resin is a monolithic sponge-like structure, so it does not mix with the ion exchange resin and fills in phase without using ion exchange membrane or other partitioning means in the deionization chamber it can. The volume ratio of the monolith phase and the ion exchange resin phase in the layered body is not particularly limited, and is appropriately determined depending on the type of ion exchange group, the purpose of treating the water to be treated, and the like. Further, the laminated structure of the layered body is not particularly limited, and the monolith phase and the ion exchange resin phase, the ion exchange resin phase and the monolith phase 2 in order from the ion exchange membrane on one side to the ion exchange membrane on the other side. Layer structure: A three-layer structure of a monolith phase, an ion exchange resin phase, a monolith phase, an ion exchange resin phase, a monolith phase, and an ion exchange resin phase can be mentioned.

  The ionic form of the mixture of the monolith and the ion exchange resin is not particularly limited, but a salt form and a regenerated form mixture are preferred in that they can alleviate swelling and shrinkage associated with the ion exchange reaction. In the deionization chamber, the physical expansion / contraction effect of the monolith is added to the swelling / shrinkage relaxation effect of the mixture of the monolith and the ion exchange resin, so that the adhesion in the deionization chamber can be ensured.

  In the present invention, the mixed ion exchanger of the cation exchanger and the anion exchanger filled in the deionization chamber is not particularly limited, and is a mixture of a cation exchanger and an anion exchanger or a cation exchanger. Examples include a laminate in which a layer and an anion exchanger layer are laminated.

  In the electric deionized water production apparatus of the present invention, the cation exchanger filled in the cathode chamber partitioned by the cathode and the cation exchange membrane is not particularly limited, and is a cation monolith, a cation exchange resin, a cation monolith and a cation exchange. A mixture of resins may be mentioned. The anion exchanger filled in the anode chamber partitioned by the anode and the anion exchange membrane is not particularly limited, and similarly, anion monoliths, anion exchange resins, and mixtures of anion monoliths and anion exchange resins can be mentioned. . Among these, the monolith is preferable in that the contact area between the monolith and the ion exchange membrane can be increased and the potential gradient can be more relaxed, and the ion exchange resin is preferable in terms of high heat resistance. The mixture of the monolith and the ion exchange resin has the monolith disposed on the side in contact with the ion exchange membrane, and the ion exchange resin disposed on the electrode side increases the contact area between the monolith and the ion exchange membrane, And it is preferable at the point which can arrange | position a heat resistant ion exchange resin in a heat_generation | fever location. The ion exchange resin filled in the electrode is not particularly limited, and examples thereof include known granular ion exchange resins used for water treatment.

  In the present invention, the water to be treated is intended for treatment of either one or both of cation and anion, and is not particularly limited as long as it does not contain turbidity. Examples include water collected from the system or an effluent from an ion chromatography separation column. The condensate circulation system of a power plant is meant to include the secondary drainage system attached to the condensate circulation main system. When water collected from the condensate circulation system of a power plant is treated water, the electric deionized water production device functions as a cation removal device that removes cation components such as ammonia, hydrazine, and sodium ions derived from seawater. To do. In this case, the treated water is sent to a measuring instrument that measures the specific resistance or conductivity, and the specific resistance or acid conductivity mainly due to HCl in the treated water is measured. When the effluent from the separation column of ion chromatography is treated water, the electric deionized water production apparatus functions as a so-called suppressor. When the ion to be measured is an anion, it is used as a decationization device, and the conductivity of the electrolyte of the eluent from the separation column of the chromatography device is suppressed, and the conductivity of the separated anion is not suppressed Improve the sensitivity of the target anion. In addition, when the ion to be measured is a cation, it is used as a deanion device, and the conductivity of the eluent from the separation column of the chromatography device is suppressed, and the conductivity of the separated cation is not suppressed. , Improve the sensitivity of the cation to be measured. In this case, the treated water is sent to a measuring instrument that measures specific resistance or conductivity.

  Next, an electric deionized water production apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of an electric deionized water production apparatus (first apparatus) of this example. The electric deionized water production apparatus 10 a includes an anion exchange membrane 4 on the anode chamber 112 side and a cation exchange membrane 3 on the cathode 111 side between the anode chamber 112 having the anode 2 and the cathode chamber 111 having the cathode 1. A deionization chamber 15 that is partitioned and filled with a mixed ion exchanger 5 of a cation exchanger and an anion exchanger adjacent to the anode chamber 112 and the cathode chamber 111 is disposed. In the anode chamber 112, an anode water inflow pipe 8a and The anode water outflow pipe 8b, the cathode chamber 111 is provided with the cathode water inflow pipe 6a and the cathode water outflow pipe 6b, and the deionization chamber 15 is provided with the treated water inflow pipe 7a and the treated water outflow pipe 7b. The anode chamber 112 defined by the anode 2 and the anion exchange membrane 4 is filled with the anion exchanger 12, and the cathode chamber 111 defined by the cathode 1 and the cation exchange membrane 3 is filled in the cation exchanger. 11 is filling The is intended.

  In the electric deionized water production apparatus 10a, a voltage is applied between the anode chamber 112 and the cathode chamber 111, the water to be treated is caused to flow into the deionization chamber 15 from the water to be treated inflow pipe 7a, and the water to be treated is discharged. It flows out of the system from 7b. On the other hand, the anode water is caused to flow from the anode water inflow pipe 8a into the anode chamber 112 and from the anode water outflow pipe 8b. Cathode water flows into the cathode chamber 111 from the cathode water inflow pipe 6a and flows out from the cathode water outflow pipe 6b. In the deionization chamber 15, the impurity cations in the water to be treated permeate the cation exchange membrane 3 and move to the cathode chamber (also the concentration chamber) 111 and are discharged together with the cathode water. Is transferred to the anode chamber (also serving as a concentration chamber) 112 and discharged together with the anode water. In the electrical deionized water production apparatus 10a, since the membrane surface 41 on the anode side of the anion exchange membrane 4 is in contact with the anion exchanger 12, the potential gradient hardly occurs on the membrane surface 41, and the anion exchange membrane 4 Don't burn. Further, since the membrane surface 31 on the cathode side of the cation exchange membrane 3 is in contact with the cation exchanger 11, the potential gradient hardly occurs on the membrane surface 31, and the cation exchange membrane 3 is not burnt. In addition, since the metal ions and hardness components that have moved from the deionization chamber 15 to the cathode chamber 111 are directly removed as electrode water, no scale is generated.

  Next, an electric deionized water production apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a schematic view of the electric deionized water production apparatus (second apparatus) of this example. The electric decationized water production apparatus 10 b is partitioned by two cation exchange membranes 3 and 3 between the anode chamber 112 and the cathode chamber 111 and filled with a cation exchanger 5 a adjacent to the anode chamber 112 and the cathode chamber 111. The decationization chamber 15a is disposed, the anode chamber 112 has an anode water inflow pipe 8a and an anode water outflow pipe 8b, and the cathode chamber 111 has a cathode water inflow pipe 6a and a cathode water outflow pipe 6b. The chamber 15a is provided with a treated water inflow pipe 7a and a treated water outflow pipe 7b, respectively. The anode chamber 112 defined by the anode 2 and the cation exchange membrane 3 is filled with a cation exchanger 12a. The cathode chamber 111 partitioned by the cathode 1 and the cation exchange membrane 3 is filled with the cation exchanger 11. The treated water inflow pipe 7a is connected to the decationization chamber 15a on the inflow side (the lower edge of the apparatus in FIG. 2) in the vicinity of the cation exchange membrane 3 on the cathode side, and the treated water outflow pipe 7b is connected to the anode side. The cation exchange membrane 3 is connected to a decation chamber 15a on the outflow side (the upper edge of the apparatus in FIG. 2). In the electrical decationized water production apparatus 10b, if the treated water outflow pipe 7b and the anodic water inflow pipe 8a are connected, it is not necessary to prepare anodized water separately. Is preferable in that no cations other than hydrogen ions move from the anode chamber 112 to the decation chamber 15a. In the electric deionized water production apparatus 10b, the anode chamber 112 may be unfilled with a cation exchanger.

  In the electric decationized water production apparatus 10b, a case where the water to be treated is water collected from the condensate circulation system of the power plant and the treated water outflow pipe 7b and the anode water inflow pipe 8a are connected will be described. That is, the water to be treated contains ammonium ions, hydrazinium ions, sodium ions derived from seawater as cations, hydroxide ions that are counter ions of ammonium ions and hydrazinium ions, and chloride ions derived from seawater as anions. . The inflow of treated water and outflow of treated water, and inflow and outflow of anode water and cathode water are the same as in the electrical deionized water production apparatus 10a. In the decation chamber 15a, ammonium ions, hydrazinium ions, sodium ions in the water to be treated, and cations that move through the cation membrane 3 from the anode chamber 112 both pass through the cation exchange membrane 3 on the cathode side. At the same time, the hydrogen ions generated by electrolysis in the anode chamber 112 move to the cathode chamber (also serving as the concentration chamber) 111, pass through the cation exchange membrane 3 and move to the decation chamber 15a, and the hydroxide in the decation chamber It reacts with ions to become water. The ions in the decation chamber become only chloride ions and hydrogen ions which are counter ions thereof, and are discharged while contained in the treated water. In the cathode chamber 111 of the electric decationized water production apparatus 10b, since the membrane surface 31 on the cathode side of the cation exchange membrane 3 is in contact with the cation exchanger 11, the potential gradient hardly occurs on the membrane surface 31, and the cation exchange membrane 3 The exchange membrane 3 does not burn. Further, since the metal ions and hardness components that have moved from the decation chamber 15a to the cathode chamber 111 are excluded as electrode water as they are, no scale is generated. The electrical decationized water production apparatus 10b (second apparatus) functions as a metal filter in order to remove metal ions when metal is contained in the water to be treated. In this case, the cathode water flowing out from the cathode chamber 111 can be increased in metal ion concentration and can be used for metal recycling.

  In the electric deionized water production apparatus 10b, the anode chamber may be either filled with an ion exchanger or not filled with an ion exchanger, but an ion exchanger, particularly one filled with a cation exchanger has strength. However, it is preferable in that the electrical resistance of the device can be reduced.

  Next, an electrical deionized water production apparatus according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic view of the electric deanion water production apparatus (third apparatus) of this example. The electric deanion water production apparatus 10c is divided between the anode chamber 112 and the cathode chamber 111 by two anion exchange membranes 4 and 4, and is filled with an anion exchanger 5b adjacent to the anode chamber 112 and the cathode chamber 111. The anion chamber 15b is disposed, the anode chamber 112 is provided with an anode water inlet pipe 8a and an anode water outlet pipe 8b, and the cathode chamber 111 is provided with a cathode water inlet pipe 6a and a cathode water outlet pipe 6b. The chamber 15 b is provided with a treated water inflow pipe 7 a and a treated water outflow pipe 7 b, and the anion exchanger 12 is filled in the anode chamber 112 defined by the anode 2 and the anion exchange membrane 4. The cathode chamber 111 partitioned by the cathode 1 and the anion exchange membrane 4 is filled with an anion exchanger 11a. The treated water inflow pipe 7a is connected to the deanion chamber 15b on the inflow side (the lower edge of the apparatus in FIG. 3) in the vicinity of the anion exchange membrane 4 on the anode side, and the treated water outflow pipe 7b is connected to the cathode side. Near the anion exchange membrane 4 is connected to a deanion chamber 15b on the outflow side (the upper edge of the apparatus in FIG. 3). In the electrical deanion water production apparatus 10c, if the treated water outflow pipe 7b and the cathode water inflow pipe 6a are connected, it is not necessary to prepare a separate cathode water, and the treated water contains anions other than hydroxyl ions. Is not included, and is preferable in that anions other than hydroxyl ions do not move from the cathode chamber 111 to the deanion chamber 15b. In the electric deanion water production apparatus 10c, the cathode chamber 111 may be unfilled with an anion exchanger.

  In the electrical deanion water production apparatus 10c, the inflow of treated water and the outflow of treated water, and the inflow and outflow of anode water and cathode water are the same as in the electrical deionized water production apparatus 10a. In the deanion chamber 15 c, both the anion in the water to be treated and the anion moving through the anion membrane 4 from the cathode chamber 111 pass through the anion exchange membrane 4 on the anode side and pass through the anode chamber (also serving as a concentration chamber) 112. And discharged with the anode water. Since cations in the water to be treated do not pass through the anion exchange membrane 4, they are discharged in a state of being contained in the water to be treated. In the anode chamber 112 of the electric deanion water production apparatus 10c, since the membrane surface 41 on the anode side of the anion exchange membrane 4 is in contact with the anion exchanger 12, the potential gradient hardly occurs on the membrane surface 41. The exchange membrane 4 does not burn.

  In the electrical deanion water production apparatus 10c, the cathode chamber may be either filled with an ion exchanger or not filled with an ion exchanger, but an ion exchanger, particularly one filled with an anion exchanger has strength. However, it is preferable in that the electrical resistance of the device can be reduced.

  EXAMPLES Next, although an Example is given and this invention is demonstrated more concretely, this is only an illustration and does not restrict | limit this invention.

  The iron-containing water to be treated was the electric decationized water production apparatus (second apparatus) shown in FIG. 2, and was passed through an apparatus having the following specifications for continuous operation for one week. The degree of increase in applied voltage was measured every 1 day, 2 days, 3 days, 4 days, and 7 days. Further, after one week, the apparatus was disassembled, and the scale generation state in the cathode chamber and the burn state of the cation exchange membrane surface in the cathode chamber were visually observed. Table 1 shows the results of increasing the applied voltage with respect to the operation time. Further, after one week, no scale was generated in the cathode chamber, and no burning of the cation exchange membrane surface in the cathode chamber was observed.

(Device specifications and operating conditions for decationization equipment)
-Cathode: SUS304 flat plate-Anode: Platinum-coated titanium flat plate-Cathode chamber filler: Cation exchange resin IR-120B (Na) standard type-Anode chamber filler: Cation exchange resin IR-120B (H) regenerative type- Decation chamber filler; Cationic monolith (40 × 50 × 80 mm rectangular parallelepiped)
・ Ion exchange capacity of cationic monolith; 4.0 mg equivalent / g in terms of dryness
・ Ion exchange membrane; Cation exchange membrane (Nafion N324 (manufactured by DuPont))
・ Decationization chamber load: Iron sulfate 100 μg Fe / L, 10 L / h
・ Cathode water; ammonia water (ammonia concentration 500 μg / L), 5 L / h
・ Anode water; treated water in decation chamber, 5L / h
・ Applied current: 0.7A (constant current)

Comparative Example 1
The same procedure as in Example 1 was performed except that the anion exchange resin IRA-402BL (OH) regenerated type was used instead of the cation exchange resin IR-120B (Na) as the filler in the cathode chamber. Table 1 shows the results of increasing the applied voltage with respect to the operation time. Further, after one week, generation of scale was observed in the cathode chamber. In addition, scorching was observed on the surface of the cation exchange membrane in the cathode chamber. It has been inferred that the function of the cation exchange membrane is lowered when it continues further from the burnt state.

  As is clear from Table 1, in Example 1, the voltage did not increase even when the iron ion load increased. In Comparative Example 1, the voltage increased as the iron ion load increased. The voltage increase in Comparative Example 1 was presumed to be due to the scale generated in the cathode chamber.

  The anion-containing water to be treated (conductivity 0.16 μS / cm) is the electric deanion water production apparatus (third apparatus) shown in FIG. Drove. One week later, the conductivity of the treated water was measured. Further, after one week, the apparatus was disassembled, and the state of scorching of the anion exchange membrane surface in the anode chamber was visually observed. As a result, after one week, no burning of the anion exchange membrane surface in the anode chamber was observed. The conductivity of the treated water was 0.055 μS / cm.

(Deanion device specifications and operating conditions)
・ Cathode: Platinum-coated titanium flat plate ・ Anode: Platinum-coated titanium flat plate ・ Cathode chamber filler: Anion exchange resin IRA-402BL (OH) regenerative type ・ Anode chamber filler: Anion exchange resin IRA-402BL (Cl) Standard type, deanion chamber filler; anion monolith (40 x 50 x 40 mm cuboid)
・ Ion exchange capacity of anionic monolith; 4.0 mg equivalent / g in terms of dryness
・ Ion exchange membrane; anion exchange membrane (AHA (manufactured by Tokuyama))
Deanion chamber loading: chloride ion 1 μg / L, sulfate ion 1 μg / L, acetate ion 10 μg / L, flow rate 15 L / h
・ Cathode water; treated water in the deanion chamber, 5 L / h
・ Anode water; cathode chamber outlet water, 5 L / h
Applied current: 0.5 A (constant current), current density: 2.5 A / dm ²

Comparative Example 2
The same procedure as in Example 2 was performed except that the cation exchange resin IR-120B (H) regenerated type was used instead of the anion exchange resin IRA-402BL (Cl) as the filler in the anode chamber. One week later, the conductivity of the treated water was measured. Further, after one week, the apparatus was disassembled, and the state of scorching of the anion exchange membrane surface in the anode chamber was visually observed. As a result, after one week, the conductivity of the treated water was 0.055 μS / cm. In addition, scorching was observed on the anion exchange membrane surface in the anode chamber. It was inferred that the function of the anion exchange membrane deteriorated when it continued further from the state of scorching.

It is a schematic diagram of the electric deionized water production apparatus of the first embodiment. It is a schematic diagram of the electric deionized water manufacturing apparatus of the second embodiment. It is a schematic diagram of the electric deionized water manufacturing apparatus of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cathode 2 Anode 3 Cation exchange membrane 4 Anion exchange membrane 5 Mixed ion exchanger 6a Cathode water inflow piping 6b Cathode water outflow piping 7a Treated water inflow piping 7b Treated water outflow piping 8a Anode water inflow piping 8b Anode water outflow piping 10a 10c Electric deionized water production apparatus 11, 5a, 12a, cation exchanger 12, 5b, 11a anion exchanger 15 deionization chamber 15a decation chamber 15b deanion chamber 31 membrane surface of cation exchanger 41 membrane of anion exchanger Surface 111 Cathode chamber 112 Anode chamber

Claims (6)

  A decation chamber, which is partitioned between two cation exchange membranes and filled with a cation exchanger adjacent to the anode chamber and the cathode chamber, is disposed between the anode chamber and the cathode chamber. The electrode water inflow pipe and the electrode water outflow pipe are provided, the decation chamber is provided with the treated water inflow pipe and the treated water outflow pipe, and the cathode chamber is defined by the cathode and the cation exchange membrane. Is an electric deionized water production apparatus filled with a cation exchanger.   A deanion chamber filled with an anion exchanger adjacent to the anode chamber and the cathode chamber is provided between the anode chamber and the cathode chamber, and the anode chamber and the cathode chamber are filled with an anion exchanger. The electrode water inflow pipe and the electrode water outflow pipe are provided, the deanion chamber is provided with the treated water inflow pipe and the treated water outflow pipe, and the anode chamber is defined by the anode and the anion exchange membrane. Is an electric deionized water production apparatus filled with an anion exchanger. The electric deionization according to claim 1 or 2 , wherein the water to be treated is water collected from a condensate circulation system of a power plant or an effluent from a separation column of ion chromatography. Water production equipment.   A decation chamber, which is partitioned by two cation exchange membranes and filled with a cation exchanger adjacent to the anode chamber and the cathode chamber, is disposed between the anode chamber and the cathode chamber. In an electric deionized water production apparatus filled with a cation exchanger, the water to be treated is allowed to flow into the decation chamber while applying a voltage between the anode and the cathode. A method for producing deionized water, wherein electrode water is allowed to flow into a chamber to remove impurity cations in water to be treated to obtain decationized water.   A deanion chamber that is partitioned by two anion exchange membranes and filled with an anion exchanger adjacent to the anode chamber and the cathode chamber is disposed between the anode chamber and the cathode chamber. In the electric deionized water production apparatus in which the anion exchanger is filled with the compartment, the water to be treated flows into the deanion chamber while applying a voltage between the anode and the cathode. A method for producing deionized water, wherein electrode water is allowed to flow into a chamber to remove impurity anions in water to be treated to obtain deanion water. The deionized water production according to claim 4 or 5 , wherein the water to be treated is water collected from a condensate circulation system of a power plant or an effluent from a separation column of ion chromatography. Method.

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