Pure water production equipment and system using electrolytic filtration

Abstract

We provide pure water production equipment and pure water production systems. [Solution] The apparatus is equipped with an anion separation section 10A equipped with an anion separation chamber 52 that supplies raw water 11 containing anion components and cation components and separates the anion components in the raw water 11 as a first discharge liquid 11A by electrofiltration, a cation separation section 10B equipped with a cation separation chamber 54 that introduces a cation liquid 16 containing cation components from which the anion components have been separated and separates the cation components as a second discharge liquid 11B by electrofiltration, and a pure water chamber 55 that discharges pure water 11C from which the anion components and cation components have been removed.

Description

[Technical Field]

[0001] The present invention relates to a pure water producing apparatus and a pure water producing system using electrofiltration. [Background technology]

[0002] Conventionally, ultrapure water used in the manufacturing process of semiconductor products is produced by treating raw water such as river water, well water, or industrial water in a pretreatment system, a primary pure water system, and a secondary pure water system in that order. In the primary pure water system, in order to make the treated water from the pretreatment system highly pure, it is treated using activated carbon adsorption equipment, deionization equipment using ion exchange resins, and reverse osmosis membrane equipment to remove ionic substances and particulate components.In addition, if necessary, a degassing equipment is used to remove carbon dioxide and oxygen dissolved in the water, and a combination of an ultraviolet irradiation device and an ion exchange polisher is used to remove organic matter from the water. In secondary pure water systems, technologies have been proposed in which the pure water treated in the primary pure water system is treated using an ion exchange polisher or ultrafiltration device to further increase the purity (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-10681 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-215679 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the primary pure water system disclosed in Patent Document 1 requires the use of a deionization device using an activated carbon adsorption device, an ion exchange resin, or the like, to achieve high purity of treated water from the pretreatment system, and when producing water over a long period of time, there is a problem that chemicals are used to regenerate the ion exchange resin. Furthermore, there is a problem that a large amount of pure water must be used to wash the equipment treated with chemicals during the regeneration process. In other words, when producing pure water, the resulting pure water is used for washing, resulting in a low yield of pure water production.

[0005] Therefore, there is a strong demand for a technology that can separate cations and anions in raw water without using chemicals or the like.

[0006] In view of the above problems, an object of the present invention is to provide a pure water production apparatus and system that use electrofiltration, which can produce pure water by passing raw water through the electrofiltration process without using chemicals or the like in the process of producing pure water, and separating cations and anions through electrofiltration. [Means for solving the problem]

[0007] The pure water producing apparatus by electrofiltration according to the first aspect of the present invention comprises: Supply raw water containing anionic components and cationic components; an anion separation unit having an anion separation chamber that separates anion components in the raw water by electrolytic filtration and outputs an anion component discharge liquid; a cation separation unit including a cation separation chamber into which a cation liquid containing cation components from which the anion components have been separated is introduced and into which the cation components are separated as a cation component discharge liquid by electrolytic filtration; a pure water chamber for discharging the pure water from which the anionic and cationic components have been removed; The present invention is characterized by the following.

[0008] A pure water producing apparatus by electrofiltration according to a second aspect of the present invention comprises: Supply raw water containing anionic components and cationic components; an anion separation unit having a cation separation chamber that separates cation components in the raw water by electrolytic filtration and outputs a cation component discharge liquid; a cation separation unit including an anion separation chamber into which an anion liquid containing an anion component from which the cation component has been separated is introduced and into which the anion component is separated as an anion component discharge liquid by electrofiltration; a pure water chamber for discharging the pure water from which the anionic and cationic components have been removed; The present invention is characterized by the following features.

[0009] A pure water producing apparatus by electrofiltration according to a third aspect of the present invention comprises: a supply chamber for supplying raw water containing anionic components and cationic components; an anion separation unit having an anion separation chamber that separates anion components in the raw water by electrolytic filtration and outputs an anion component discharge liquid; a cation separation unit including a cation separation chamber into which a cation liquid containing cation components from which the anion components have been separated is introduced and into which the cation components are separated as a cation component discharge liquid by electrolytic filtration; a pure water chamber for discharging the pure water from which the anionic and cationic components have been removed as filtrate, The anion separation unit is disposed on both sides of the anion separation chamber; a flat anode electrode having a through hole disposed on the supply chamber side; a cathode filter plate electrode having a pore and a diaphragm having pores for separating the anion component; a cation chamber into which the separated cation components flow together with water as a cation liquid; The cation separation unit is a cation separation chamber into which the cation liquid is introduced; The device is characterized by comprising an anode filter plate electrode, which is disposed on both sides of the cation separation chamber and is equipped with a diaphragm for separating cation components, and a flat cathode electrode.

[0010] A pure water producing apparatus according to a fourth aspect of the present invention comprises: In a third aspect, The anion separation section and the cation separation section are arranged in this order from the supply chamber side.

[0011] A pure water producing apparatus according to a fifth aspect of the present invention comprises: In a third aspect, The cation separation section and the anion separation section are arranged in this order from the supply chamber side.

[0012] A pure water producing apparatus according to a sixth aspect of the present invention comprises: In a third aspect, The apparatus is characterized in that it includes a discharge part that discharges the cationic liquid in the cation chamber to the outside as cationic wastewater.

[0013] A pure water producing apparatus according to a seventh aspect of the present invention comprises: In a third aspect, The pure water chamber is characterized by having a pH adjusting electrode provided in the pure water chamber for adjusting the pH.

[0014] An eighth aspect of the water purifying apparatus according to the present invention comprises: In a third aspect, The method is characterized in that a surface treatment layer using fluorine gas is formed on the surface of the diaphragm.

[0015] A ninth aspect of the water purifying apparatus according to the present invention comprises: In a third aspect, The cathode filter plate electrode, the flat anode electrode, the anode filter plate electrode, and the flat cathode electrode are provided on their respective surfaces. It is characterized by forming a coating layer with a high relative dielectric constant.

[0016] A water purifying apparatus according to a tenth aspect of the present invention comprises: In a ninth aspect, The high dielectric constant coating layer is characterized by being subjected to a poling treatment.

[0017] An eleventh aspect of the pure water producing system according to the present invention comprises: The pure water producing apparatus according to any one of the first to tenth aspects is used as a pre-treatment device, The system is characterized by being equipped with a polisher filled with ion exchange resin to perform finishing treatment on the obtained pure water, thereby producing highly purified pure water.

[0018] A pure water producing system according to a twelfth aspect of the present invention comprises: In the pure water producing system of the eleventh aspect, At the rear side of the polisher, The first to tenth pure water production systems are further installed as post-treatment systems to produce ultrapure water.

[0019] A pure water producing system according to a thirteenth aspect of the present invention comprises: In the pure water producing system of the eleventh aspect, The voltage of the downstream water purifying apparatus is set higher than the voltage of the upstream water purifying apparatus.

[0020] A pure water producing system according to a fourteenth aspect of the present invention comprises: A water purifying apparatus according to any one of the first to tenth aspects; The apparatus is characterized by comprising an electrolyte adjusting section that adjusts the obtained pure water by adding electrolyte components, thereby producing drinking water. [Effects of the Invention]

[0021] According to the present invention, cations and anions contained in raw water can be efficiently separated, and in the process of producing pure water, no chemicals are used to regenerate the ion exchange resin, and the obtained pure water can be used to produce pure water without cleaning the equipment. [Brief explanation of the drawings]

[0022] [Figure 1A] 1 is a schematic diagram of a pure water production system according to a first embodiment of the present invention. [Figure 1B] FIG. 1 is a schematic diagram of a pure water production system according to a second embodiment of the present invention. [Figure 2A]FIG. 10 is a schematic diagram of a pure water production system according to a third embodiment of the present invention. [Figure 2B] FIG. 10 is a schematic diagram of another pure water production system according to the third embodiment of the present invention. [Figure 3A] FIG. 4 is a schematic diagram showing the behavior of ions according to the second embodiment of the present invention. [Figure 3B] FIG. 4 is a schematic diagram showing the behavior of ions according to the second embodiment of the present invention. [Figure 4A] FIG. 10 is a schematic diagram of a pure water production system according to a fourth embodiment of the present invention. [Figure 4B] FIG. 10 is a schematic diagram of a pure water production system according to a fourth embodiment of the present invention. [Figure 5] FIG. 10 is a schematic diagram of a pure water production system according to a fifth embodiment of the present invention. [Figure 6] Schematic diagram of a pure water production system according to a sixth embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram of a pure water production system according to a seventh embodiment of the present invention. [Figure 8] FIG. 10 is a schematic diagram of a pure water production system according to an eighth embodiment of the present invention. [Figure 9] FIG. 10 is a schematic diagram of a drinking water production system according to a ninth embodiment of the present invention. [Figure 10A] FIG. 3 is a schematic view of another electrolytic filtration device according to the first embodiment of the present invention. [Figure 10B] FIG. 3 is a schematic view of a filter plate electrode of another electrolytic filtration device according to the first embodiment of the present invention. [Figure 10C] FIG. 3 is a schematic view of a flat anode electrode of another electrolytic filtration device according to the first embodiment of the present invention. [Figure 10D] FIG. 3 is a schematic view of a filter medium of another electrolytic filtration device according to the first embodiment of the present invention. [Figure 11] 1 is a schematic diagram of a poling treatment of a high dielectric constant coating layer according to the present invention; FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following mode for carrying out the invention (hereinafter referred to as the embodiment). Furthermore, the components in the following embodiment include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiment can be combined as appropriate. In the embodiments of this specification, the same components are denoted by the same reference numerals throughout. Note that this embodiment is merely an example that embodies the configuration of the present invention, and various design changes can be made without departing from the scope of the claims.

[0024] [Embodiment 1] FIG. 1A is a schematic diagram of a pure water producing system according to a first embodiment of the present invention. The pure water production system 100A according to the first embodiment is a system that separates cations and anions dissociated in a solvent (polar solvent, e.g., water) that is raw water 11, which is an electrolyte solution, and produces pure water.

[0025] Ion dissociation is a general process by which molecules (or ionic compounds such as salts and complexes) separate or split into smaller particles such as atoms, ions, and radicals, usually reversibly. The ionic crystal lattice breaks down when dissolved in water, and dissociation refers to the separation of ions that occurs when a solid ionic compound dissolves. As an example, using the formula unit of sodium chloride (NaCl) contained in tap water, sodium chloride (NaCl) dissociates in water into one sodium ion (Na ion; positive ion) and one chloride ion (Cl ion; negative ion). In other words, salt (sodium chloride) that dissolves in water (HO) dissociates into its ions and is an electrolyte. In the electrolyte solution, sodium chloride (NaCl) is completely dissociated into water and becomes a cation, sodium ion (Na + ) and the anion chloride ion (Cl -) and exists in an ionic state. In addition to dissociated ionic components, tap water also contains positively charged particles (PtCl +) , negatively charged particles (Ptcl - ) is also included. In the following, sodium ions (Na + ) and positively charged particles (Ptcl + ) and "positively charged components / cationic components", chloride ions (Cl - ) and negatively charged particles (Ptcl - ) are also called "negatively charged components / anionic components."

[0026] Here, positively charged particles include, for example, some organic substances and some inorganic substances such as alumina, while negatively charged substances include, for example, many organic substances and many inorganic substances such as silica. Note that the total amount of positively and negatively charged organic components can be determined by measuring the TOC (total organic carbon) in the water.

[0027] The pure water production system 100 of the first embodiment is composed of components of an anion separation section 10A and a cation separation section 10B. The components located at the bottom of FIG. 1A are explanatory diagrams of an anion separation unit 10A of the first embodiment. As shown in the lower part of FIG. 1A, the anion separation unit 10A separates cations (Na + ), anions (Cl - ), positively charged particles (Ptcl + ), negatively charged particles (Ptcl - ), and an anion separation chamber 52 which supplies feed water (hereinafter referred to as "raw water") 11, which is an electrolyte solution containing cations (Na + ) a cathode filter plate electrode 14 equipped with a diaphragm (filter material) 13 for separating the separated cations (Na + and a cation chamber 53 into which the alkaline solution 16 flows together with water.

[0028] The cathode filter plate electrode 14 is composed of a cathode first electrode 14A and a cathode second electrode 14B, and further, a diaphragm (filter material) 13, which is an insulator having pores 13a, is sandwiched between the cathode first electrode 14A and the cathode second electrode 14B. Here, the diaphragm 13 is made of an insulating material, and may be, for example, a nonwoven fabric made of fibers such as PP (polypropylene), PE (polyethylene), NY (nylon), PTFE (polytetrafluoroethylene), PVDF (Polyvinylidene DiFluoride; a fluorine-based resin), or cellulose.

[0029] The anion separation unit 10A further includes a first power source 41 electrically connected to the flat anode electrode 15 and the cathode first electrode 14A, and a second power source 42 electrically connected to the cathode first electrode 14A and the cathode second electrode 14B. Here, the electrode configuration is such that the cathode second electrode 14B is at a first potential (V1=10V), the cathode first electrode 14A is at a second potential (V2=20V), and the flat anode electrode 15 is at a third potential (V3=30V), resulting in an absolute potential difference of 20V. The absolute value of the cathode potential supplied from the second power supply 42 increases with increasing distance from the anion separation chamber 52 (V2 (20 V)>V1 (10 V)).

[0030] The electrode configuration is not limited to the configuration of Figure 1A, and a configuration is also possible in which an earth is connected to the cathode first electrode 14A, the cathode first electrode 14A is used as a reference electrode, the potential (V2) of the cathode first electrode 14A is set to 0 V, the potential (V1) of the cathode second electrode 14B is set to -10 V, and the potential (V3) of the flat anode electrode 15 is set to +10 V, and the absolute value of the voltages is changed while the potential difference between them remains unchanged.

[0031] Here, a cathode electric field Ec is generated between cathode first electrode 14A and cathode second electrode 14B. Cathode electric field Ec exerts a repulsive force that inhibits negatively charged ions (Cl−) from migrating from supply chamber 12 to cation chamber 17.

[0032] The cathode electric field Ec generated between the cathode first electrode 14A and the cathode second electrode 14B is a positive ion (Na + ) and positively charged water molecules and positively charged particles (Ptcl + ) from the anion separation chamber 5212 to the cation chamber 53. + ) and positively charged water molecules and positively charged particles (Ptcl + ) is drawn toward the cation chamber 53, generating an electroosmotic flow (see arrows F1 and F2 in FIG. 1). As a result, the water in the anion separation chamber 52 moves faster than when it moves to the cation chamber 53 simply under the filtration pressure of a pump or the like. Therefore, the amount of water moving from the anion separation chamber 52 to the cation chamber 53 per unit time increases.

[0033] Then, the cationic liquid 16A that has moved to the cation chamber 53 is discharged to the outside from an outlet (not shown) of the cation chamber 53 due to filtration pressure. The anion component discharge liquid 11A from which cations have been separated in the anion separation chamber 52 has a reduced cation concentration, and is discharged to the outside from an outlet (not shown) of the anion separation chamber 52 due to filtration pressure.

[0034] Here, the filtration pressure by the supply pump (not shown) is preferably set so that the pressure (gauge pressure) in the supply chamber 12, which is an enclosed space, is slightly higher than atmospheric pressure, for example, 0.005 MPa or more and 0.5 MPa or less, preferably 0.02 MPa or more and 0.1 MPa or less.

[0035] Here, the cathode filter plate electrodes 14 (cathode first electrode 14A, cathode second electrode 14B) are provided with a plurality of holes 14a penetrating in the left-right direction in the figure. Water in the supply liquid 11 moves through the pores 14a of the electrodes 14. The diameter of the holes 14a in the cathode first electrode 14A and the cathode second electrode 14B is, for example, 0.1 μm or more and 5000 μm or less, and more preferably 100 μm or more and 1000 μm or less. Note that the diameters of the holes 14a in the cathode first electrode 14A and the cathode second electrode 14B do not have to be the same.

[0036] Furthermore, on the surfaces of the cathode filter plate electrode 14 (first cathode electrode 14A, second cathode electrode 14B) and the flat plate anode electrode 15, an anti-galvanic corrosion layer (not shown) is provided. Examples of the electrolytic corrosion prevention layer include an insulating coating layer and a conductive precious metal layer. Examples of materials for the electrolytic corrosion prevention layer include, but are not limited to, titanium, aluminum, magnesium, and tantalum. Examples of materials for the conductive precious metal layer include, but are not limited to, platinum, gold, and palladium. In the case of an insulating coating layer, the thickness of the electrolytic corrosion prevention layer is preferably, for example, about 5 μm to 30 μm, more preferably about 5 μm to 10 μm. Furthermore, the thickness of the conductive precious metal layer, such as platinum, gold, or palladium, is preferably, for example, about 0.5 μm to 10 μm, more preferably about 1 μm to 5 μm. This electrolytic corrosion prevention layer inhibits surface corrosion of the cathode filter plate electrode 14 and the flat plate anode electrode 15. Furthermore, because the cathode filter plate electrode 14 and the flat plate anode electrode 15 have an insulating coating layer, they do not come into contact with the liquid constituting the feed solution 11. As a result, even if a potential is applied to the cathode filter plate electrode 14 and the flat plate anode electrode 15, electrolysis is unlikely to occur between the surfaces of the cathode filter plate electrode 14 and the flat plate anode electrode 15 and the liquid.

[0037] The cathode first electrode 14A faces the flat-plate anode electrode 15 across the anion separation chamber 52. The distance D1 between the cathode first electrode 14A and the flat-plate anode first electrode 15 is, for example, 0.1 mm or more and 100 mm or less, more preferably 0.1 mm or more and 40 mm or less.

[0038] The distance D2 between the first cathode electrode 14A and the second cathode electrode 14B is not particularly limited, but is, for example, 0.1 mm to 20 mm, more preferably 0.1 mm to 2 mm. Note that the smaller the distance D2 between the first cathode electrode 14A and the second cathode electrode 14B, the stronger the strength of the cathode electric field Ec generated between the first cathode electrode 14A and the second cathode electrode 14B.

[0039] Diaphragm 13 can be made of, for example, cellulose such as filter paper (membrane) or nanofiber, but the present invention is not limited to this. Taking filter paper as an example, the pore size is approximately 1 micron (a pore diameter 1000 times larger than 1 nanometer). Since water molecules are sub-nanometers in size, water can easily pass through diaphragm 13. As a result, the pump that pumps supply liquid 11 into supply chamber 12 allows water to freely pass through diaphragm 13.

[0040] On the other hand, negative ions (Cl) are introduced into the cathode first electrode 14A on the cathode side. - ) approaching, the negative electrode and the negative ions repel each other due to the Coulomb repulsion, and therefore the negative ions cannot pass through the cathode first electrode 14A. Conversely, when positive ions (Na + ) approaches, the positive electrode and the positive ions repel each other due to Coulomb's repulsive force.

[0041] As mentioned above, filter paper can be used as the diaphragm 13, but it is more preferable to use a diaphragm having a dielectric effect. The diaphragm having a dielectric effect is made of an insulating material, and may be, for example, a nonwoven fabric made of fibers such as PP (polypropylene), PE (polyethylene), NY (nylon), PTFE (polytetrafluoroethylene), PVDF (Polyvinylidene DiFluoride; a fluorine-based resin), or cellulose. In this way, by placing the diaphragm 13 having a dielectric effect between the first cathode electrode 14A and the second cathode electrode 14B, the strength of the cathode electric field Ec acting between the first cathode electrode 14A and the second cathode electrode 14B increases. The diameter of the diaphragm 13 and the pores 13a is preferably, for example, 0.2 mm or less.

[0042] The components located at the top of FIG. 1A are explanatory diagrams of the cation separation unit 10B of the first embodiment. As shown in FIG. 1A, the cation separation unit 10B separates cations (Na + ) and positively charged particles (Ptcl + ) and ions are separated.

[0043] As shown in the upper part of FIG. 1A, the cation separation unit 10B includes a cation separation chamber 54 into which the cation liquid 16A is introduced, anode filter plate electrodes 24 arranged on both sides of the cation separation chamber 54 and equipped with diaphragms 13 that separate the cation components, a flat cathode electrode 25, and a pure water chamber 55 into which pure water 10C from which the cation components have been separated flows.

[0044] Here, the anode filter plate electrode 24 is composed of a first anode electrode 24A and a second anode electrode 24B, and further, a diaphragm 13, which is an insulator having fine holes, is sandwiched between the first anode electrode 24A and the second anode electrode 24B. The diaphragm 13 is made of an insulating material, and may be, for example, a nonwoven fabric made of fibers such as PP (polypropylene), PE (polyethylene), NY (nylon), or cellulose.

[0045] The ion separation section 10B further includes a third power supply 43 electrically connected to the flat cathode electrode 25 and the anode first electrode 24A, and a fourth power supply 44 electrically connected to the anode first electrode 24A and the anode second electrode 24B.

[0046] As described above, the cationic liquid 16A containing cationic components is introduced into the cation separation chamber 54. The cationic components (sodium ions (Na + ), positively charged particles (Ptcl + )) is a positive ion, and is therefore blocked by the anode first electrode 24A (in FIG. 1A, sodium ions (Na + ), positively charged particles (Ptcl + As a result, the cation components (sodium ions (Na + ), positively charged particles (Ptcl + As a result, the cationic component discharge liquid 11B discharged from the cation separation chamber 54 is in a state in which the cationic components are concentrated.

[0047] The distance D3 between the first anode electrode 24A and the second anode electrode 24B is not particularly limited, but is, for example, 0.1 mm to 20 mm, more preferably 0.1 mm to 2 mm. Furthermore, the smaller the distance D3 between the first anode electrode 24A and the second anode electrode 24B, the stronger the anode electric field Ea generated between the first anode electrode 24A and the second anode electrode 24B.

[0048] The holes 24a in the anode first electrode 24A and the anode second electrode 24B communicate with the supply chamber 12 and the anion chamber 27. The diameters of the holes 24a in the anode first electrode 24A and the anode second electrode 24B are, for example, 0.1 μm or more and 5000 μm or less, and more preferably 100 μm or more and 1000 μm or less. The diameters of the holes 24a in the anode first electrode 24A and the anode second electrode 24B do not have to be the same.

[0049] An example of producing pure water using tap water as raw water 11 will be described with reference to FIG. 1A.

[0050] As described above, the ion state in the anion separation chamber 52 is determined by the cations (sodium ions: Na + ) and anions (chlorine ions: Cl - ) and dissociated into The negative cathode first electrode 14A disposed in the anion separation chamber 52 is charged with sodium ions (Na + ) is attracted to the positive ion, sodium ion (Na + ) is drawn in, and as a result, water (H2O) also passes through, while sodium ions (Na + ) penetrates through the membrane. At the same time, positively charged particles (Ptcl + ) also moves into the cation chamber 53.

[0051] In contrast, the anion component (chlorine ion (Cl - ), negatively charged particles (Ptcl - )) is an anion, and is therefore blocked by the negative cathode first electrode 14A (chlorine ion (Cl ) in FIG. 1A). - ), negatively charged particles (Ptcl - ) bounces back), and cannot pass through the cathode first electrode 14A. - ), negatively charged particles (Ptcl - As a result, the anion component discharge liquid 11A discharged from the anion separation chamber 52 contains cations (Na + ) decreases, and the anion component (chlorine ion (Cl - ), negatively charged particles (Ptcl - )) becomes concentrated. This concentrated anion component (chlorine ion (Cl - ), negatively charged particles (Ptcl - )) is discharged to the outside as an anion component discharge liquid 11A.

[0052] In the present invention, in the anion separation unit 10A, the cathode filter plate electrode 14A blocks the anion component discharge liquid 11A and discharges it to the outside, and also discharges the cation component (Na + , positively charged particles (Ptcl + )) permeates through the diaphragm 13 that constitutes the cathode filter plate electrode 14. As a result, the permeated water contains the cation component ((Na +), positively charged particles (Ptcl + )) also acts as a carrier water.

[0053] As a result, according to the anion separation unit 10A, the cation chamber 52 contains the cation component (Na + , positively charged particles (Ptcl + )) is transferred to obtain a cationic liquid (alkaline liquid) 16A.

[0054] The cation separation chamber 54 is separated from the cation by the anode filter plate electrode 24A. + , positively charged particles (Ptcl + )) is discharged as a cationic component discharge liquid 11B.

[0055] As a result, both ionic components (anionic components and cationic components) and organic and inorganic particulate components are removed from the supplied raw water 11, and pure water 11B is introduced into the pure water chamber 55.

[0056] The results of a tap water filtration test using the device of embodiment 1 are shown in [Table 1] and [Table 2].

[0057] [Table 1]

[0058] [Table 1] shows the COD, TOC, pH, electrical conductivity (EC), ion concentration (Na) of the anion component discharge liquid 11A, the cation component discharge liquid 11B, and the filtrate (pure water 11C) after 60 minutes of supplying tap water as raw water to the pure water production system. + , Ca 2+ , NO3 - ) results are shown.

[0059] As shown in Table 1, the tap water as raw water 11 was neutral, the anion component effluent 11A was acidic, the cation component effluent 11B was alkaline, and the filtrate, pure water 11C, was weakly acidic. Although it was measured using a simple measuring device, the COD and TOC of pure water 11C were "0.0", and the ion concentration (Na + , Ca 2+ , NO3 - ) was also "0".

[0060] [Table 2]

[0061] As shown in Table 2, when purified water filtered through a commercially available water purifier is used as raw water, it was confirmed that the residual ionic (electrolyte) components in the purified water can be separated with high efficiency.

[0062] In this manner, in this embodiment, pure water 11C can be obtained from raw water 11 without using an ion exchange resin as in the past. In this embodiment, pure water is not produced using an ion exchange resin as in the past, so there is no need to regenerate the ion exchange resin. As a result, no acid or alkaline chemicals, such as those used to regenerate ion exchange resins, are used. Therefore, because no chemicals are used, there is no need to use a portion of the pure water that has been produced to clean the pure water production apparatus, and 100% of the pure water obtained can be used as a product.

[0063] In this embodiment, electrodes with high-dielectric-constant coating layers 14b, 15b such as PVDF can be used for the cathode filter plate electrode 14 (first electrode 14A, second electrode 14B) and the flat anode electrode 15, as shown in Figures 10A, 10B, and 10C. PVDF is an abbreviation for polyvinylidene difluoride, a type of fluororesin. Because PVDF is an insulating layer with a high dielectric constant, it is possible to construct an "electrostatic field model" between these electrodes that exhibits the behavior of a capacitance (capacitor). The cathode filter plate electrode 24 (first electrode 24A, second electrode 24B) and the flat cathode electrode 25 may also be electrodes having coating layers 24b, 25b of high dielectric constant such as PVDF.

[0064] By using the electrodes of the "electrostatic field model" as in this embodiment, the current flowing between the electrodes (between the second electrode 14B and the first electrode 14A, and between the first electrode 14A and the flat anode electrode 15) becomes almost zero. As a result, no electrolysis occurs, and electrolytic corrosion of the electrodes is suppressed. In addition, there is no change in the pH of the solution, and no Joule heat is generated. As a result, there is no change in the substance to be separated or the liquid quality due to pH fluctuations or thermal denaturation.

[0065] Examples of other materials with a high relative dielectric constant that have insulating and dielectric properties similar to those of the above-mentioned PVDF include the following. 1) P(VDF-TrFE): Poly(vinylidene fluoride-trifluoroethylene) 2) P(VDF-CTFE): Poly(vinylidene fluoride-chlorotrifluoroethylene) 3) Polyamide 11 (Nylon (registered trademark) 11) 4) PTFE: Polytrifluoroethylene 5) Liquid crystalline ferroelectric polymers 6) MXene / PVDF composite Here, MXene is a general term for composite atomic layer compounds made of early transition metals (such as titanium and vanadium) and light elements (carbon or nitrogen), and has a sheet-like structure similar to graphene.

[0066] Examples of methods for forming the high-dielectric-constant coating layers 14b and 15b include the following. 1) A coating layer of a predetermined thickness is formed on the surface of the electrode using PVDF by electrostatic spraying or powder sintering. 2) A coating layer of a predetermined thickness is formed on the surface of the electrode by screen printing or inkjet printing with PVDF ink. 3) A PVDF film (for example, 7-200 μm) is vacuum laminated and solution cast to form a coating layer of a predetermined thickness on the surface of the electrode. 4) A PVDF solution is prepared, and a coating layer of a predetermined thickness is formed on the surface of the electrode by dipping.

[0067] After the coating layer is formed, a poling treatment (dipole alignment treatment 9) is performed on the high-dielectric-constant coating layer. This poling treatment involves applying an external electric field, such as corona discharge, to the coating layer to align the molecular orientation and the random orientation of the electric dipoles in a direction perpendicular to the electrode plane, as shown in Figure 11. By performing the poling treatment, high dielectric polarization can be generated in the high-dielectric-constant coating layer when a voltage is applied.

[0068] Here, the electrode in which a platinum coating layer (corrosion-resistant layer) is formed on the surface of the titanium electrode described above is a "conductive electric field model." When using this "conductive electric field model" electrode, the electrolyte (cation, H + , anion, OH - ) through which an electric current flows between the electrodes.

[0069] If the "conductive electric field model" electrodes are used, electrolysis occurs, generating hydrogen and oxygen at both electrodes. Electrolytic corrosion of the electrodes occurs, so as a countermeasure, it is necessary to coat the electrode surface with, for example, platinum, as mentioned above. Furthermore, the pH of the solution changes, generating Joule heat.

[0070] In addition, the force acting on particles (electric field strength) and the particle movement speed (electrophoretic speed) are almost the same in the ``conductive electric field model'' composed of an electrode with a platinum coating on the surface of, for example, a titanium electrode, and the ``electrostatic electric field model'' composed of an electrode with a thin film coating layer with a high dielectric constant such as PVDF (for example, layer thickness of 1 μm to 100 μm) applied to the surface of a conductive electrode such as stainless steel, copper, or carbon.

[0071] Here, the configuration of the electrostatic electric field model is the same for electrode 14, which is made up of first electrode 14A and second electrode 14B equipped with filter media, as well as for flat-plate anode electrode 15. Note that the configuration of the electrostatic electric field model can also be applied to anode filter plate electrode 24 equipped with filter media 13 and flat-plate cathode electrode 25.

[0072] The surface treatment method for the filter medium 13 will be described.

[0073] In this embodiment, as shown in FIGS. 10A and 10D, a surface treatment layer 13b using fluorine gas (direct fluorination treatment) may be formed.

[0074] Here, the surface treatment using fluorine gas utilizes the extremely high reactivity of fluorine gas to improve the surface characteristics of the filter medium 13. In other words, fluorine gas is brought into contact with the filter medium 13, which is the base material, to chemically modify the surface of the base material.

[0075] By applying this fluorine treatment to the surface of the material of the filter medium 13, it is possible to give the material electrical surface properties similar to those of PVDF (Polyvinylidene DiFluoride) or PTFE (Polytetrafluoroethylene), etc. As a result, the material exhibits a dipole orientation effect when electricity is applied.

[0076] [Embodiment 2] The pure water production system 100B of the second embodiment is a modified example of the pure water production system 100A of the first embodiment. Fig. 1B is a schematic diagram of the pure water production system of the second embodiment according to the present invention. 1B, the difference from the first embodiment is that the anion separation section 10A is provided after the cation separation section 10B. As a result, the cation component discharge liquid 11B is discharged to the outside at the upstream side, and the anion component discharge liquid 11A is discharged to the outside at the downstream side.

[0077] [Embodiment 3] In the pure water production systems 100A and 100B of the first and second embodiments, the anion separation section 10A and the cation separation section 10B are configured as independent units, but in the pure water production system 200 of this embodiment, these are integrated.

[0078] Fig. 2A is a schematic diagram of a pure water production system according to a third embodiment of the present invention, and Fig. 2B is a schematic diagram of another pure water production system according to the third embodiment of the present invention. As shown in Figure 2A, the pure water manufacturing apparatus 200A-1 is equipped with a supply chamber 51 that supplies raw water 11 containing anionic components (◇-: the symbol in the figure is a "-" inside ◇) and cationic components (◇+: the symbol in the figure is a "+" inside ◇), an anion separation section 10A equipped with an anion separation chamber 52 that separates the anionic components (◇-) in the raw water 11 as anionic component discharge liquid 11A by electrofiltration, a cation separation section 10B equipped with a cation separation chamber 54 that introduces cationic liquid 16A containing cationic components (◇+) from which the anionic components (◇-) have been separated and separates the cationic components (◇+) as a second discharge liquid 11B by electrofiltration, and a pure water chamber 55 that introduces pure water 11C from which the anionic and cationic components have been removed.

[0079] The anion separation section 10A is arranged on both sides of the anion separation chamber 52, and is equipped with a flat anode electrode 61 having a through hole 61a (hole diameter: 0.2 mm to 2.0 mm) arranged on the supply chamber 51 side, a diaphragm (filter material) 13 having pores 13a (pore diameter: 0.2 mm or less) that separate the anion components (◇-), a cathode filter plate electrode 14 having pores 14a (pore diameter: 500 nm or less; 200 to 500 nm), and a cation chamber 53 into which the separated cation components (◇+) flow together with water as a cation liquid (hereinafter also referred to as "alkaline liquid") 16A.

[0080] The cation separation section 10B is arranged on the cation chamber 53 side and includes a reversal electrode 62A having a through hole 62a (hole diameter: 0.2 mm to 2.0 mm), a diaphragm (filter material) 13 having pores 13a that separate the cation component (◇+), and a cathode filter plate electrode 24 having pores 14a.

[0081] The separation behavior of ion components in the configuration of the pure water producing apparatus 200A-1 in FIG. 2A will be described using the schematic diagram showing the behavior of ions in FIG. 3A. Raw water 11 introduced into supply chamber 51 passes through through-hole 61a. Here, the upper side of Fig. 3A is defined as cation components (positively charged substances) (◇+), the lower side as anion components (negatively charged substances) (◇-), and the middle as electrically neutral.

[0082] The flat anode electrode 61 is a positive electrode (anode electrode), and the cation components (◇+) in the raw water 11 are forcibly introduced into the anion separation chamber 52 by flowing in from a supply line (not shown) through which the raw water 11 is supplied.

[0083] However, when the raw water 11 is introduced into the anion separation chamber 52, the anion components (◇-) in the raw water 11 are attracted toward the flat anode electrode 61 (positive pole (anode electrode)) while being introduced into the anion separation chamber 52. As a result, a concentration gradient is formed due to the electrophoresis phenomenon in which the concentration of the anion components (◇-) is higher near the anode electrode 61.

[0084] Thereafter, the anion components are removed by the anode filter plate electrode 14, and the cation components pass through 14 and are introduced into the cation chamber 53 as a cationic liquid 16A.

[0085] Therefore, the cationic components (◇+) in the cationic liquid 16 introduced from the cation chamber 53 into the cation separation chamber 54 are attracted toward the flat-plate inversion electrode 62 (negative pole (cathode electrode)) and introduced into the cation separation chamber 54, resulting in a concentration gradient due to the electrophoresis phenomenon in which the concentration of the cationic components (◇+) is higher near the inversion electrode (cathode electrode) 62A.

[0086] The behavior of ions in Figure 3B is the case when the reversing electrode 62A is inverted, as in the pure water production system 200A-2 in Figure 2B. With this reversing electrode 62B, the behavior in the cation chamber 53 is different, the separation efficiency is improved, and the concentration gradient is reversed.

[0087] [Embodiment 4] In the pure water producing systems 200A-1 and 200A-2B of the third embodiment, the anion separation unit 10A and the cation separation unit 10B are arranged in this order from the supply chamber 51 side, but the present invention is not limited to this. 4A and 4B are schematic diagrams of a pure water production system according to a fourth embodiment of the present invention.

[0088] In the pure water producing systems 200B-1 and 200A-B of the fourth embodiment, an anion separation unit 10B and a cation separation unit 10A are arranged in this order from the supply chamber 51 side.

[0089] [Embodiment 5] FIG. 5 is a schematic diagram of a pure water production system according to the fifth embodiment. The pure water production system 100C of embodiment 5 is a modified example of the pure water production system 100A of embodiment 1. As shown in Fig. 5, the pure water production system 100C of embodiment 5 is provided with a discharge part that discharges the cationic liquid 16 in the cation chamber 53 to the outside as a cationic component discharge liquid 11D.

[0090] When the raw water 11 contains a large proportion of cationic components, the cationic liquid 16 in the cation chamber 53 is discharged to the outside as cationic liquid wastewater 11D. This makes it possible to reduce the proportion of cationic components remaining in the pure water 11C introduced into the pure water chamber 55. That is, the separated cation liquid 16 is actively discharged to the outside as cation liquid wastewater 11D before being introduced into the cation separation chamber 54. This prevents cation components from leaking into the pure water 11C introduced into the pure water chamber 55. As a result, the quality of ion separation when producing the pure water 11C can be improved.

[0091] [Embodiment 6] FIG. 6 is a schematic diagram of a pure water production system according to a sixth embodiment. As shown in FIG. 6, a pure water producing system 200D of the sixth embodiment is the same as the pure water producing system of the second embodiment, except that a pH adjusting electrode 63 for adjusting pH is provided in the pure water chamber 55.

[0092] It is desirable that the pure water be neutral, so a pH adjusting electrode 63 is provided as a monitoring electrode to monitor this. It is desirable that the pure water does not have an imbalance of ions.

[0093] As shown in Table 1, the pH of raw water (tap water) 11 is about 7.3, but the anion component discharge liquid 11A is acidic, with a pH of 3.0. On the other hand, the cation component discharge liquid 11B is alkaline, with a pH of about 11.2. The filtrate 11C, which is pure water, has a pH of about 5.0. For this reason, a monitoring electrode 63 is installed to monitor the pH state, thereby controlling the electrolysis of the water.

[0094] This results in hydrogen ions (H + ), hydroxide ion (OH - The bias in the distribution of ions (ions) can be adjusted arbitrarily. Generating a large amount of hydrogen ions and reversing the process changes the concentration of hydroxide ions, and a pH meter 65 is installed to confirm this. In addition, the electrolysis zone can be controlled arbitrarily by increasing the voltage to promote electrolysis or decreasing the voltage to suppress electrolysis.

[0095] As a result, pH adjustment becomes possible without the need for pH-adjusting chemicals, and the water can be adjusted to any desired pH level (pure water with a pH of about 7.0). The pH adjusting electrode 63 has the same configuration as the inlet electrode 61 and the reversal electrode 62, and is provided with holes, and is not particularly limited as long as the hole diameter does not cause filtration resistance of the raw water 11.

[0096] [Embodiment 7] FIG. 7 is a schematic diagram of a pure water production system according to the seventh embodiment. 7, the pure water producing system of the seventh embodiment is equipped with the pure water producing apparatus 200 (200A to 200D) of the first to sixth embodiments as a pre-treatment device, and a mixed-bed polisher 30 filled with ion exchange resin for finishing the obtained pure water 11C, thereby producing highly purified pure water 11D. This polisher may be made of a known ion exchange resin for ultrapure water, which has extremely low initial elution and elution over time.

[0097] The analysis results for this highly purified pure water 11D are shown in Table 3. As shown in Table 3, the EC (Electrical Conductivity) was 1 μS / cm, and the TOC reading on the simple measuring device was 0.00 (less than 0.005 mg / L).

[0098] [Table 3]

[0099] [Embodiment 8] FIG. 8 is a schematic diagram of a pure water production system according to the eighth embodiment. As shown in FIG. 8, a pure water production system 200 (200A to 200D) may be installed as a post-treatment device downstream of the mixed bed polisher 30 to further reduce the EC value and refine the water to produce so-called ultrapure water 11F.

[0100] In this case, when multiple stages of pure water production systems are installed, the same voltage configuration may be used, but the voltage of the pure water production system 200-2 in the subsequent stage may be set higher than the voltage of the pure water production system 200-1 in the preceding stage.

[0101] This is because the downstream pure water production system 200-2 can be operated at a higher voltage (e.g., 80V-400V) to compensate for the reduced number of ions in the upstream pure water production system 200-1. This is because the electrolytes are removed in the upstream stage, so electrolysis does not occur in the downstream stage.

[0102] [Embodiment 9] FIG. 9 is a schematic diagram of a drinking water production system according to a ninth embodiment. 9, an electrolyte adjusting section 501 for adjusting the electrolyte components in the pure water 11C is installed downstream of the pure water producing apparatus 200 (200A to 200D). This electrolyte adjusting section 501 adds various mineral components suitable for drinking water 11G.

[0103] The main mineral components are sodium (Na), magnesium (Mg), calcium (Ca), and potassium (K). The taste and hardness of the 11G drinking water are adjusted by balancing the content of these four major minerals.

[0104] In addition to the essential mineral components, iron and zinc may be added, and vanadium (V), germanium (Ge), silica, etc. may also be included. This allows artificial drinking water to be obtained according to the intended use and needs.

[0105] In this embodiment, tap water is used as the raw water 11, but the raw water 11 is not limited to tap water. For example, seawater can be used as the raw water 11 and desalinated to produce pure water. In this case, by using electrodes of the "electrostatic field model" with a high relative dielectric constant such as PVDF as described above, the current flowing between the electrodes (between second electrode 14B and first electrode 14A, and between first electrode 14A and flat anode electrode 15) becomes almost zero. As a result, electrolysis does not occur, and electrolytic corrosion of the electrodes is also suppressed. [Industrial Applicability]

[0106] The present invention can be applied to all water purifiers and water purifier systems that can efficiently separate pure water from raw water. [Explanation of symbols]

[0107] 100A, 100B pure water production equipment 10A Anion separation section 10B Cation separation section 11 Raw water 11A Anion component discharge liquid 11B Cationic component discharge liquid 11C pure water 11D Highly purified pure water 11F Ultra pure water 13 Diaphragm 14 Cathode filter plate electrode 15 Flat anode electrode 24 Anode filter plate electrode 25 Flat cathode electrode 52 Anion Separation Chamber 53 Cation Chamber 54 Cation Separation Chamber 55 Pure water chamber 61A Reversal electrode 61B Reversal electrode 61a through hole 62 Reversal electrode

Claims

1. Supply raw water containing anionic components and cationic components; an anion separation unit having an anion separation chamber that separates anion components in the raw water by electrolytic filtration and outputs an anion component discharge liquid; a cation separation unit including a cation separation chamber into which a cation liquid containing cation components from which the anion components have been separated is introduced and into which the cation components are separated as a cation component discharge liquid by electrolytic filtration; a pure water chamber for discharging the pure water from which the anionic and cationic components have been removed; A pure water production apparatus using electrolytic filtration, comprising:

2. Supply raw water containing anionic components and cationic components; an anion separation unit having a cation separation chamber that separates cation components in the raw water by electrolytic filtration and outputs a cation component discharge liquid; a cation separation unit including an anion separation chamber into which an anion liquid containing an anion component from which the cation component has been separated is introduced and into which the anion component is separated as an anion component discharge liquid by electrofiltration; a pure water chamber for discharging the pure water from which the anionic and cationic components have been removed; A pure water production apparatus using electrolytic filtration, comprising:

3. a supply chamber for supplying raw water containing anionic components and cationic components; an anion separation unit having an anion separation chamber that separates anion components in the raw water by electrolytic filtration and outputs an anion component discharge liquid; a cation separation unit including a cation separation chamber into which a cation liquid containing cation components from which the anion components have been separated is introduced and into which the cation components are separated as a cation component discharge liquid by electrolytic filtration; a pure water chamber for discharging the pure water from which the anionic and cationic components have been removed as filtrate, The anion separation unit is disposed on both sides of the anion separation chamber; a flat anode electrode having a through hole disposed on the supply chamber side; a cathode filter plate electrode having a pore and a diaphragm having pores for separating the anion component; a cation chamber into which the separated cation components flow together with water as a cation liquid; The cation separation unit is a cation separation chamber into which the cation liquid is introduced; A pure water production apparatus using electrofiltration, characterized by comprising: an anode filter plate electrode equipped with a diaphragm for separating cation components, and a flat cathode electrode, which are arranged on both sides of the cation separation chamber.

4. 4. The pure water producing apparatus using electrolytic filtration according to claim 3, wherein the anion separation section and the cation separation section are arranged in this order from the supply chamber side.

5. 4. The pure water producing apparatus using electrolytic filtration according to claim 3, wherein the cation separation section and the anion separation section are arranged in this order from the supply chamber side.

6. 4. The pure water producing apparatus using electrolytic filtration according to claim 3, further comprising a discharge section for discharging the cationic liquid in the cation chamber to the outside as cationic wastewater.

7. 4. The pure water producing apparatus according to claim 3, further comprising a pH adjusting electrode provided in said pure water chamber for adjusting pH.

8. 4. The apparatus for producing pure water by electrolytic filtration according to claim 3, wherein a surface treatment layer using fluorine gas is formed on the surface of said diaphragm.

9. The cathode filter plate electrode, the flat anode electrode, the anode filter plate electrode, and the flat cathode electrode are provided on their respective surfaces.

4. The pure water producing apparatus using electrolytic filtration according to claim 3, wherein a coating layer with a high relative dielectric constant is formed.

10. 10. The apparatus for producing pure water by electrofiltration according to claim 9, wherein the coating layer with a high dielectric constant is subjected to a poling treatment.

11. The pure water producing apparatus according to any one of claims 1 to 10 is used as a pre-treatment device, The pure water production system is characterized by having a polisher filled with ion exchange resin that performs finishing treatment on the obtained pure water, thereby producing highly purified pure water.

12. At the rear stage of the polisher, 12. The pure water producing system according to claim 11, further comprising a pure water producing apparatus according to any one of claims 1 to 10 as a post-treatment device for producing ultrapure water.

13. 13. The pure water producing system according to claim 12, wherein the voltage of the downstream pure water producing apparatus is set higher than the voltage of the upstream pure water producing apparatus.

14. The water purifying apparatus according to any one of claims 1 to 10, and an electrolyte adjusting section that adjusts the obtained pure water by adding electrolyte components, thereby producing drinking water.

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