Electric field filtration device and method for manufacturing filter material for electric field filtration device

Abstract

To provide an electric field filtration device and a method for manufacturing a filter material for the electric field filtration device, which improves separation efficiency, functions adequately in low-voltage regions, and achieves high functionality.SOLUTION: A device includes a supply chamber 12 for supplying a supply liquid 11 containing positively charged components, a cathode filter plate electrode 14 equipped with a filter material 13 having pores 13a for separating the positively charged components, positioned on both sides of the supply chamber 12, a flat anode electrode 15, and a filtrate chamber 17 into which the filtrate separated from the positively charged components flows. The filter material is made of a high-dielectric-constant material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electrofiltration device and a method for manufacturing a filter medium for the electrofiltration device. [Background technology]

[0002] Conventional filtration methods use direct filtration, where a filter medium filters out fine particles, but performance deteriorates due to clogging during filtration. To solve this problem, the inventors previously proposed a non-contact filtration method that utilizes the electrical repulsion of an electric field barrier formed on a laminated electrode filter plate as an electrolytic filtration device (Patent Document 1). [Prior art documents] [Non-patent literature]

[0003] [Patent Document 1] Patent No. 7399604 Summary of the Invention [Problem to be solved by the invention]

[0004] However, electrofiltration devices use filter paper as the filter material for the diaphragm sandwiched between the electrodes, and there is a demand for materials that can further improve separation efficiency, function adequately in the low voltage range, and do not decrease in rejection rate under high flow rate conditions.

[0005] In view of the above problems, the present invention provides an electrolytic filtration device and a method for manufacturing a filter medium for the electrolytic filtration device, which have improved separation efficiency as an electrolytic filtration characteristic, and which are highly functional and can fully function in a low voltage range. [Means for solving the problem]

[0006] In order to achieve the above object, the technical means of the first invention comprises a supply chamber for supplying a supply liquid containing a positively charged component; a cathode filter plate electrode provided with a filter medium having fine pores for separating positively charged components, and a flat anode electrode, the cathode filter plate electrode being disposed on both sides of the supply chamber; a filtrate chamber into which the filtrate from which the positively charged components have been separated flows, The electrolytic filtration device is characterized in that the filter medium is made of a high dielectric constant material.

[0007] The technical means of the second invention is a supply chamber for supplying a supply liquid containing a negatively charged component; an anode filter plate electrode provided with a filter medium having fine holes for separating negatively charged components, the anode filter plate electrode being disposed on both sides of the supply chamber; and a flat cathode electrode; a filtrate chamber into which the filtrate from which the negatively charged components have been separated flows, The electrolytic filtration device is characterized in that the filter medium is made of a high dielectric constant material.

[0008] The technical means of the third invention is a supply chamber for supplying a supply liquid containing a positively charged component and a negatively charged component; a cathode filter plate electrode provided on each side of the supply chamber and having a filter medium with pores for separating positively charged components; and an anode filter plate electrode provided on each side of the supply chamber and having a filter medium with pores for separating negatively charged components. a cation chamber into which the separated positively charged components flow together with water as a cation solution; an anion chamber into which the separated negatively charged component flows together with water as an anion liquid; The electrolytic filtration device is characterized in that the filter medium is made of a high dielectric constant material.

[0009] The fourth aspect of the present invention is the first aspect of the present invention, wherein the filter medium is In a resin polymer liquid made from nanofiber (NF) raw material, The electrolytic filtration device is characterized by being made by dispersing and kneading high-dielectric-constant materials.

[0010] The fifth aspect of the present invention is the first aspect of the present invention, wherein the filter medium is The electrolytic filtration device is characterized by having a high dielectric constant material powder attached to the surface of nanofiber (NF) yarn.

[0011] The sixth aspect of the present invention is the first aspect of the present invention, wherein the filter medium is On the filtering side of a nanofiber sheet formed from a woven fabric of nanofiber yarn or a nonwoven fabric of nanofiber yarn, The electrolytic filtration device is characterized in that fine particle powder of a high dielectric constant material is laminated as a thin film using a medium.

[0012] The seventh aspect of the present invention is the method according to any one of the first to third aspects of the present invention, The electrolytic filtration device is characterized in that a surface treatment layer using fluorine gas is formed on the surface of the filter material.

[0013] The eighth aspect of the present invention is the first aspect of the present invention, A cathode filter plate electrode provided with the filter material and a flat anode electrode are provided on the surface thereof. The electrolytic filtration device is characterized by the formation of a coating layer with a high relative dielectric constant.

[0014] The ninth aspect of the present invention is the second aspect of the present invention, On the surface of the anode filter plate electrode provided with the filter material and the flat cathode electrode, The electrolytic filtration device is characterized by the formation of a coating layer with a high relative dielectric constant.

[0015] The tenth aspect of the present invention is the third aspect of the present invention, On the surface of the cathode filter plate electrode provided with the filter medium and the anode filter plate electrode provided with the filter medium, The electrolytic filtration device is characterized by the formation of a coating layer with a high relative dielectric constant.

[0016] The eleventh invention of the present invention is any one of the eighth to tenth inventions, The electrolytic filtration device is characterized in that the coating layer having a high dielectric constant is subjected to a poling treatment.

[0017] The twelfth aspect of the present invention is a method for producing a filter medium for an electrolytic filtration device according to any one of the first to third aspects of the present invention, A process of dispersing and kneading a high dielectric constant material into a resin polymer liquid made from nanofiber (NF) raw material to obtain a mixed raw material polymer; a spinning step of spinning nanofiber yarn from the mixed raw material polymer; and forming the obtained nanofiber yarn into a sheet shape by weaving it or forming it into a nonwoven fabric.

[0018] The thirteenth aspect of the present invention is a method for producing a filter medium for an electrolytic filtration device according to any one of the first to third aspects of the present invention, The method for producing the filter medium for an electric field filtration device is characterized in that the filter medium is made by adhering a powder of a high dielectric constant material to the surface of the nanofiber yarn.

[0019] The fourteenth aspect of the present invention is a method for producing a filter medium for an electrolytic filtration device according to any one of the first to third aspects of the present invention, The filter material is On the filtering side of a nanofiber sheet formed from a woven fabric of nanofiber yarn or a nonwoven fabric of nanofiber yarn, The method for manufacturing a filter medium for an electric field filtration device is characterized by laminating fine particle powder of a high dielectric constant material.

[0020] The fifteenth aspect of the present invention is a method for producing a filter medium for an electrolytic filtration device according to any one of the first to third aspects of the present invention, The filter material is The present invention relates to a method for manufacturing a filter medium for an electrolytic filtration device, which is characterized by being made of a high molecular weight polymer made of a high dielectric constant material.

[0021] The sixteenth aspect of the present invention is the method according to any one of the first to third aspects of the present invention, The filter material is The method for manufacturing a filter medium for an electrolytic filtration device is characterized by coating or impregnating a high molecular weight polymer made of a high dielectric constant material onto the surface of a nanofiber molded body formed into a sheet shape.

[0022] The seventeenth aspect of the present invention is the method according to any one of the first to third aspects of the present invention, a step of dispersing and kneading a high molecular weight polymer made of a high dielectric constant material into a resin polymer made of a nanofiber raw material to obtain a mixed raw material polymer; a spinning step of spinning nanofiber yarn from the mixed raw material polymer; and forming the obtained nanofiber yarn into a sheet shape by weaving it or forming it into a nonwoven fabric to form a filter medium. [Effects of the Invention]

[0023] According to the present invention, by using a high dielectric constant material (a material with a high dielectric constant) as the filter material for the diaphragm sandwiched between the electrodes, the remarkable effects are achieved, such as sufficient function in the low voltage range and no decrease in rejection rate even under high flow rate conditions. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic diagram of an electrolytic filtration device according to a first embodiment of the present invention. [Figure 2] FIG. 4 is a schematic view of an electrolytic filtration device according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a schematic view of an electrolytic filtration device according to a third embodiment of the present invention. [Figure 4A] FIG. 3 is a schematic view of another electrolytic filtration device according to the first embodiment of the present invention. [Figure 4B] 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 4C] 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 4D] 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 5] 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

[0025] 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.

[0026] [Embodiment 1] FIG. 1 is a schematic diagram of an electrolytic filtration device according to a first embodiment of the present invention. The electrolytic filtration device 10A according to the first embodiment is a device that separates positively charged components (positively charged particles, cations) dissociated in a solvent (polar solvent; for example, water) that is an electrolyte solution (hereinafter also referred to as a "feed liquid") 11. Examples of polar solvents include, but are not limited to, water, methanol, ethanol, and propanol. Here, the electrolyte solution (electrolyte solution or electrolyzed water) that is the supply liquid is a general term for a liquid in which an electrolyte, which is a substance that dissociates (ionizes) into ions and exhibits electrical conductivity, is dissolved.

[0027] 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. Taking the formula unit of sodium chloride (NaCl) as an example, sodium chloride (NaCl) dissociates in water into one sodium ion (Na ion; cation (positive) ion) and one chloride ion (Cl ion; anion (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.

[0028] In this embodiment, sodium ions of sodium chloride (NaCl) are used as positively charged particles, and chloride ions (Cl) of sodium chloride (NaCl) are used as negatively charged particles. - ) will be used as an example for explanation, but the present invention is not limited to this. As shown in FIG. 1, the electrolytic filtration device 10A of the first embodiment is configured to filter cations (Na + ) and anions (Cl - Electrolyte solution supply chambers (hereinafter referred to as "supply chambers") 12 supply an electrolyte solution (NaCl+H2O: hereinafter referred to as "supply solution") 11 containing cations (Na + The cathode filter plate electrode 14 is equipped with a filter material 13, which is a diaphragm that separates the cations (Na + and a cation chamber 17 into which the alkaline solution 16 flows together with water as a cation solution (hereinafter also referred to as "alkaline solution"). Here, the cathode filter plate electrode 14 is composed of a cathode first electrode 14A and a cathode second electrode 14B, and further, a filter plate 13, which is a diaphragm (filter material) that is an insulator having pores 13a, is sandwiched between the cathode first electrode 14A and the cathode second electrode 14B.

[0029] The electrofiltration device 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), the absolute potential difference is 20V.

[0030] The absolute value of the cathode potential supplied from the second power supply 42 increases with increasing distance from the supply chamber 12 (V2 (20V)>V1 (10V)).

[0031] The electrode configuration is not limited to the configuration shown in FIG. 1. Alternatively, the cathode first electrode 14A may be earthed, the cathode first electrode 14A may be used as a reference electrode, the potential (V2) of the cathode first electrode 14A may be set to 0 V, the potential (V1) of the cathode second electrode 14B may be set to -10 V, and the potential (V3) of the flat anode electrode 15 may be set to +10 V, and the absolute value of the voltages may be changed while the potential difference between them remains unchanged.

[0032] Here, a cathode electric field Ec is generated between the cathode first electrode 14A and the cathode second electrode 14B. The cathode electric field Ec is generated by the negatively charged ions (Cl - ) from the supply chamber 12 to the cation chamber 17.

[0033] 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 from the supply chamber 12 toward the cation chamber 17. + ) and positively charged water molecules are drawn toward the cation chamber 17, generating an electroosmotic flow (see arrows F1 and F2 in FIG. 1). As a result, the water in the supply chamber 12 moves faster than when it moves to the cation chamber 17 simply under the filtration pressure of a pump or the like. Therefore, the amount of water moving from the supply chamber 12 to the cation chamber 17 per unit time increases.

[0034] The cation liquid 16 that has moved to the cation chamber 17 is then discharged to the outside from an outlet (not shown) of the cation chamber 17 due to filtration pressure. First supply / discharge liquid 11A from which cations have been separated in supply chamber 12 has a reduced cation concentration, and is discharged to the outside from an outlet (not shown) of supply chamber 12 due to filtration pressure.

[0035] 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.

[0036] 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 holes 14a of the electrodes 14.

[0037] Additionally, a galvanic corrosion prevention layer (not shown) is provided on the surfaces of the cathode filter plate electrode 14 (cathode first electrode 14A, cathode second electrode 14B) and the flat plate anode electrode 15. Examples of the galvanic corrosion prevention layer include an insulating coating layer and a conductive precious metal layer. Examples of materials for the galvanic 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 galvanic 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 galvanic corrosion prevention layer inhibits corrosion of the surfaces of the cathode filter plate electrode 14 and the flat plate anode electrode 15. Furthermore, the cathode filter plate electrode 14 and the flat plate anode electrode 15 have an insulating coating layer and are therefore not in contact with the liquid that constitutes the feed liquid 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 surface of the cathode filter plate electrode 14 and the flat plate anode electrode 15 and the liquid.

[0038] Cathode first electrode 14A faces flat-plate anode electrode 15 across supply chamber 12. Distance D1 between cathode first electrode 14A and flat-plate anode 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.

[0039] 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.

[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 cannot pass through the cathode first electrode 14A on the side. Conversely, when positive ions (Na + ) approaches, the positive electrode and the positive ions repel each other due to Coulomb's repulsive force.

[0041] Here, by placing filter material 13, which is a diaphragm having a dielectric effect, between cathode first electrode 14A and cathode second electrode 14B, the force of the cathode electric field Ec acting between cathode first electrode 14A and cathode second electrode 14B increases.

[0042] In this embodiment, electrodes with high-dielectric-constant coating layers 14b, 15b such as PVDF can be used for the cathode filter plate electrode (first electrode 14A, second electrode 14B) 14 and the flat anode electrode 15, as shown in FIGS. 4A, 4B, and 4C. PVDF is an abbreviation for polyvinylidene difluoride, a type of fluororesin. Because PVDF is an insulating layer with a high dielectric constant, an "electrostatic field model" that exhibits the behavior of a capacitance (capacitor) can be constructed between these electrodes.

[0043] By using the electrodes of the "electrostatic field model" as in this embodiment, the current flowing between the electrodes (between 14B and 14A, and between 14A and 15) becomes almost zero. As a result, electrolysis does not occur, and electrolytic corrosion of the electrodes is also suppressed. In addition, there is no change in the pH of the solution, and Joule heat is not 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.

[0044] 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.

[0045] 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.

[0046] After forming the coating layer, the high-dielectric-constant coating layer is subjected to a poling treatment (dipole alignment treatment). This poling treatment involves applying an external electric field, such as corona discharge, to the coating layer, aligning the molecular orientation and the random orientation of electric dipoles in a direction perpendicular to the electrode plane, as shown in Figure 5. By performing the poling treatment, high dielectric polarization can be generated in the high-dielectric-constant coating layer when a voltage is applied.

[0047] Here, the electrode that forms a platinum coating layer (corrosion-resistant layer) on the surface of the titanium electrode mentioned above is the "conductive electric field model." When using this "conductive electric field model" electrode, in the electrolyte solution, the electrolyte (cation, H + , anion, OH - ) through which an electric current flows between the electrodes.

[0048] 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.

[0049] 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.

[0050] Here, the configuration of the electrostatic electric field model is the same for electrode 14 consisting 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, which will be described later, and flat plate cathode electrode 25.

[0051] Next, an example of separating cations by supplying a sodium chloride solution as the supply liquid 11 into the supply chamber 12 will be described with reference to FIG.

[0052] As described above, the ion state in the supply chamber 12 is positive ions (sodium ions: Na + ) and anions (chlorine ions: Cl - ) and dissociated into A negative cathode first electrode 14A disposed in the supply chamber 12 is charged with a positive ion, sodium ion (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 + ) is transparent.

[0053] In contrast, chloride ions (Cl -) is an anion, and is blocked by the negative cathode first electrode 14A (chlorine ion (Cl) in FIG. 1). - ) bounces back), and cannot pass through the cathode first electrode 14A. - ) bounces back. - As a result, the first supply / discharge liquid 11A discharged from the supply chamber 12 contains cations (Na + ) decreases, and chloride ions (Cl - ) is concentrated.

[0054] In the present invention, the cation (Na + ), water also passes through the filter material 13, which is a diaphragm that constitutes the cathode filter plate electrode 14. As a result, the permeated water contains cations (Na + ) and does not require the separate supply of purified water or other water. Incidentally, the cation exchange membranes and anion exchange membranes according to the prior art are only capable of selectively permeating and separating ions, and are almost or only slightly permeable to water.

[0055] As a result, in the electrolytic filtration device 10A, the cation chamber 17 is filled with positively charged substances such as cations Na + A cation liquid (alkaline liquid) 16 in which the cations have been transferred can be obtained.

[0056] In this embodiment, examples of the filter material 13 that is a diaphragm include nanofiber (NF) made of a high dielectric constant material, and filter cloth or filter paper made of a high molecular weight polymer with a high relative dielectric constant and a high permittivity.

[0057] By using nanofibers (NF) made from high-dielectric constant materials and high-molecular polymers with high relative and dielectric constants as filter cloth, it is possible to achieve a high negative zeta potential at low voltage and increase repulsion. As a result, when increasing the area of ​​electrolytic filtration equipment, it is possible to reduce power consumption and improve the functionality of the filter media.

[0058] Here, nanofibers are fibrous materials with a diameter of 1 nm to 100 nm and a length 100 times or more the diameter, and the pore diameters formed by the entanglement of the fibers are approximately 0.5 to 0.1 μm. Therefore, since water molecules are sub-nanometers in size, water can easily pass through filter medium 13. As a result, the water can pass freely through filter medium 13 by the pump that sends supply liquid 11 into supply chamber 12.

[0059] The filter medium, which is a diaphragm made of a high dielectric constant material according to this embodiment, will be described in further detail below.

[0060] 1) First filter media structure The filter medium 13 of the first filter medium structure is made by dispersing and kneading a high dielectric constant material in a resin polymer liquid made from nanofiber (NF) raw material.

[0061] Specifically, fine particle powder with high relative permittivity and dielectric constant (e.g., BaTiO3; e.g., 20-30 μm powder) is used as a pigment or filler and dispersed and kneaded into a resin polymer liquid of nanofiber (NF) raw material, which is the electrode filter material. Nanofiber yarn is spun from the mixed raw polymer material, and this nanofiber yarn is woven or formed into a sheet as a nonwoven fabric to form the filter material for the electric field filter.

[0062] 2) Second filter media structure The filter medium 13 of the second filter medium structure is made by adhering high-dielectric-constant material powder to the surface of nanofiber (NF) yarn.

[0063] Specifically, the surface of the nanofiber yarn is coated with fine particle powder with high relative permittivity and dielectric constant (e.g., BaTiO3; e.g., 20-30 μm powder), and this yarn is then woven into a nanofiber filter cloth or formed into a sheet as a nonwoven fabric to form a filter material for an electric field filter.

[0064] 3) Third filter media structure The filter material 13 of the third filter material structure is formed by laminating a thin film of fine particle powder of a high dielectric constant material (fine particles with a high dielectric constant) using a medium on the filtering surface side of a nanofiber sheet formed from a woven fabric of nanofiber yarn or a nonwoven fabric of nanofiber yarn.

[0065] Specifically, fine particle powder with high relative permittivity and dielectric constant (e.g., BaTiO3; e.g., 20-30 μm powder) is used on the filtering side of a sheet made of woven or nonwoven nanofiber yarn, and a thin film is formed and laminated using a cross-linking agent as a medium to form a filter medium for an electric field filter.

[0066] Here, examples of fine particle powders with high relative permittivity and dielectric constant include perovskite structure materials such as barium titanate (BaTiO3) and transition metal oxides consisting of a ternary system of RMO3. The perovskite structure has a cubic lattice in which three different types of atoms or ions are arranged in a specific positional relationship: atom (A) at the corner of the cube, atom (B) at the center of the cube, and atom (X) at the center of the cube's face.

[0067] In addition to using fine particles with a high relative dielectric constant and a high dielectric constant, a liquid ferroelectric material of an organic polymer may be used.

[0068] 4) Fourth filter media structure The fourth filter material structure is made of a high molecular weight polymer made of a high dielectric constant material. Here, representative materials of the high molecular weight polymer include, for example, benzothianobenzothiophene (molecular formula: C14H8S2; BTBT) and dialkylbenzothianobenzothiophene.

[0069] Specifically, filter cloth or filter material formed into a sheet from a high molecular weight polymer with a high relative permittivity and dielectric constant is surface coated using an inkjet printing method or a vacuum deposition method, or the filter cloth or filter material is impregnated using a dipping method to form the filter material for an electric field filter.

[0070] 5) Fifth filter media structure The fifth filter material structure is to disperse and knead a high molecular weight polymer with a high relative permittivity and dielectric constant as a pigment or filler into a resin polymer of nanofiber (NF) raw material, which is the electrode filter material, and then spin nanofiber yarn from this mixed raw material polymer. This nanofiber yarn is then woven or formed into a sheet as a nonwoven fabric to form the filter material for the electric field filter.

[0071] 6) Sixth filter media structure Sixth filter material structure: A high molecular weight polymer with a high relative permittivity and dielectric constant is coated on the surface of nanofiber yarn, and then this yarn is woven into a nanofiber filter cloth or formed into a sheet as a nonwoven fabric to form a filter material for an electric field filter.

[0072] By using the above 1) first filter material structure to 6) sixth filter material structure as the diaphragm filter material sandwiched between the electrodes, the electrolytic filtration device can function sufficiently in the low voltage range and the rejection rate does not decrease even under high flow rate conditions, which is a remarkable effect.

[0073] In addition to the material of the filter medium 13, the surface treatment method of the filter medium 13 will be described.

[0074] In this embodiment, a surface treatment layer (direct fluorination treatment) 13b using fluorine gas may be formed on the filter material 13 having any of the above-mentioned 1) first filter material structure to 6) sixth filter material structure, as shown in Figures 4A and 4D.

[0075] 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.

[0076] 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.

[0077] [Embodiment 2] In addition to the structure of the first embodiment, the electrolytic filtration device may have the basic structures of the second embodiment (see FIG. 2) and the third embodiment (see FIG. 3).

[0078] FIG. 2 is a schematic diagram of the electrolytic filtration device of the second embodiment. The same components as those in embodiment 1 are denoted by the same reference numerals and will not be described. Although sodium chloride (NaCl) is used as an example in this embodiment, the present invention is not limited to this. As shown in FIG. 2, the electrolytic filtration device 10B of this embodiment is a device that separates anions dissociated in a solvent (polar solvent; for example, water).

[0079] As shown in FIG. 2, the electrolytic filtration device 10B is configured to filter cations (Na + ) and anions (Cl - A supply chamber 12 supplies a supply solution 11 containing anions (Cl), and two supply chambers 12 are disposed on both sides of the supply chamber 12. - The anode filter plate electrode 24 is provided with a filter material 13, which is a diaphragm that separates the separated anions (Cl - and a cation chamber 27 into which the anion solution (hereinafter also referred to as "acid solution") 26 flows together with water.

[0080] Here, the anode filter plate electrode 24 is composed of an anode first electrode 24A and an anode second electrode 24B, and further, a filter material 13, which is an insulating diaphragm having fine pores, is sandwiched between the anode first electrode 24A and the anode second electrode 24B. Examples of the filter material 13 that is this diaphragm include nanofibers (NF) made of the dielectric material as described above, and filter cloth or filter paper made of a high molecular weight polymer with a high relative dielectric constant and permittivity.

[0081] The electrofiltration device 10B further includes a third power source 43 electrically connected to the flat cathode electrode 25 and the anode first electrode 24A, and a fourth power source 44 electrically connected to the anode first electrode 24A and the anode second electrode 24B.

[0082] An example in which a sodium chloride solution (NaCl+H2O) is placed in the supply chamber 12 as the supply liquid 11 will be described. As described above, the ion state in the supply chamber 12 is positive ions (sodium ions: Na + ) and anions (chlorine ions: Cl - ) and an anion, chloride ion (Cl ). - ) is attracted to the negative ion, chloride ion (Cl - ) is drawn in, resulting in chloride ions passing through while water (H2O) also passes through.

[0083] In contrast, sodium ions (Na + ) is a positive ion, and is blocked by the anode first electrode 24A (in FIG. 2, sodium ions (Na + ) bounces back), and cannot pass through the anode first electrode 24A. + As a result, the second supply / discharge liquid 11B discharged from the supply chamber 12 contains chloride ions (Cl - ) decreases, and cations (Na + ) is concentrated.

[0084] 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.

[0085] The holes 24a of the anode first electrode 24A and the anode second electrode 24B communicate the supply chamber 12 with the anion chamber 27. The holes 24a of the anode first electrode 24A and the anode second electrode 24B have a diameter of, for example, 0.1 μm or more and 5000 μm or less, more preferably 100 μm or more and 1000 μm or less. The diameter of the holes 24a in the first anode electrode 24A and the second anode electrode 24B does not have to be the same.

[0086] In the present invention, as described in the first embodiment, anions (Cl - ) and water permeates. As a result, the permeated water contains anions (Cl - ) and does not require the separate supply of purified water. As a result, the anions (Cl - ) There is no need to separately supply purified water or other water as carrier water. The cation exchange membranes and anion exchange membranes according to the prior art are only capable of selectively permeating and separating ions, and are almost or only slightly permeable to water.

[0087] As a result, the inside of the anion chamber 27 is filled with negatively charged substances, such as anions Cl. - An anion liquid (acidic liquid) 26 in which the anions have been transferred can be obtained.

[0088] In addition, a filter medium 13, which is a diaphragm having a dielectric effect, may be placed between the first anode electrode 24A and the second anode electrode 24B to increase the force of the anode electric field Ea acting between the first anode electrode 24A and the second anode electrode 24B.

[0089] [Embodiment 3] 3 is a schematic diagram of an electrolytic filtration device according to embodiment 3. The same components as those in embodiments 1 and 2 are denoted by the same reference numerals and their description will be omitted. As shown in FIG. 3, the electrolytic filtration apparatus 10C of this embodiment is a combination of the electrolytic filtration apparatus 10A of embodiment 1 and the electrolytic filtration apparatus 10B of embodiment 2, and separates cations and anions to obtain an alkaline solution 16 and an acidic solution 26. As shown in FIG. 3, the electrolytic filtration device 10C of the third embodiment includes an electrolyte solution supply chamber (hereinafter referred to as "supply chamber") 12 that supplies a supply liquid 11 of an electrolyte solution (e.g., NaCl solution) containing cations and anions, and two electrolytic solution supply chambers (hereinafter referred to as "supply chambers") 12 that are disposed on both sides of the supply chamber 12 and supply a cation (Na + ) and a cathode filter plate electrode 14 equipped with a filter material 13, which is a diaphragm that separates anions (Cl - ) and the anode filter plate electrode 24 equipped with a filter material 13 which is a diaphragm for separating the separated cations (Na + ) flows into the cation chamber 17 together with water as a cation solution (alkaline solution) 16, and the separated anions (Cl - and an anion chamber 27 into which the acidic solution 26 flows together with water as an anion solution (acidic solution). In this embodiment, examples of the filter material 13, which is a diaphragm in the cathode filter plate electrode 14, include nanofiber (NF) made of a high dielectric constant material as described above, and filter cloth or filter paper made of a high molecular weight polymer with a high relative dielectric constant and dielectric constant.

[0090] Next, an example of separating cations and anions by supplying a sodium chloride solution as the supply liquid 11 into the supply chamber 12 will be described with reference to FIG.

[0091] As described above, the ion state in the supply chamber 12 is positive ions (sodium ions: Na + ) and anions (chlorine ions: Cl - ) and dissociated into A negative cathode first electrode 14A disposed in the supply chamber 12 is charged with a positive ion, sodium ion (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 + ) is transparent.

[0092] In contrast, chloride ions (Cl - ) are anions, and are therefore blocked by the negative cathode first electrode 14A and cannot pass through the cathode first electrode 14A.

[0093] In the present invention, the cation (Na + ) permeates through the filter material 13, which is a diaphragm that constitutes the cathode filter plate electrode 14. As a result, the cations (Na + ) There is no need to separately supply water such as purified water to the cation chamber 17 as carrier water.

[0094] In addition, in the supply chamber 12, an anode filter plate electrode (anode first electrode 24A, anode second electrode 24B) 24 disposed opposite the cathode filter plate electrode 14 is supplied with an anion, chlorine ion (Cl - ) is drawn in. The anion, chloride ion (Cl - ) is drawn in, resulting in chloride ions passing through while water (H2O) also passes through.

[0095] In contrast, sodium ions (Na + ) is a positive ion, and is therefore blocked by the anode first electrode 24A and cannot pass through the anode first electrode 24A.

[0096] As a result, sodium ions (Na + ) is concentrated in the anion chamber 27. - ) is concentrated. As a result, the third supply / discharge liquid 11C discharged from the supply chamber 12 contains sodium ions (Na + ) decreases, and chloride ions (Cl - ) also decreases.

[0097] Here, anions (Cl - ) permeates, and water also permeates. As a result, the permeated water contains anions (Cl - ) and does not require the separate supply of purified water or other water.

[0098] The ion exchange membranes used in conventional ion separation technology are almost impermeable to water and only function to separate ions. As a result, when producing alkaline solution 16 and acidic solution 26 using the electrolytic filtration device 10C of this embodiment, there is no need to supply purified water as carrier water.

[0099] As described above, according to the electrolytic filtration device 10C of this embodiment, the ionic state (sodium ions (Na + ) and chloride ions (Cl - ) mixed state: pH = 7.0), sodium ions (Na + ) permeates and sodium ions (Na + ) is concentrated. At the same time, chloride ions (Cl - ) permeates and chloride ions (Cl) enter the anion chamber 27. - ) is concentrated.

[0100] The separation of cations and anions in this electrofiltration device 10C was confirmed using pH and BTB reagent. Here, a 0.05% aqueous solution of sodium chloride (NaCl) was used as the feed solution 11, and the pH was adjusted with a carbonate buffer to a pH of 7.0. At the same time, the pH status in each chamber was visualized by coloring using BTB (bromothymol blue; BTB) test solution.

[0101] As a result of this confirmation, it was found that the ion state (sodium ion (Na+ ) and chloride ions (Cl - ) (a mixed state with alkaline solution 16: pH = 7.0) was subjected to ion separation, and the pH of the alkaline solution 16 discharged from the cation chamber 17 became 11.8, and the pH of the acidic solution 26 discharged from the anion chamber 27 became 2.4.

[0102] Furthermore, when tested with a BTB reagent, the feed solution (pH = 7.0) 11 supplied to the feed chamber 12 was green, but the alkaline solution (pH 11.8) 16 in the cation chamber 17 changed to blue, and the acidic solution (pH 2.4) 26 in the anion chamber 27 changed to yellow. Furthermore, in a flame color reaction test using a copper wire, the alkaline solution 16 turned orange due to sodium ions, and the acidic solution 26 turned green due to copper chloride (CuCl2), confirming that ion separation was achieved reliably in each flame color reaction test.

[0103] As a result, the circulating liquid, which is the third supply / discharge liquid 11C discharged from the supply chamber 12, contains sodium ions (Na + ) decreases, and chloride ions (Cl - ) also decreases (pH = 4.5).

[0104] According to this embodiment, cations and anions are separated at the cathode filter plate electrode 14 and the anode filter plate electrode 24 by applying a predetermined voltage, and the separated water also permeates the cathode filter plate electrode 14 and the anode filter plate electrode 24 as ion carrier water, so there is no need to separately add water (purified water, etc.) as ion carrier water as in the conventional method.

[0105] During ion separation, a voltage is applied to the electrodes (cathode filter plate electrode 14, anode filter plate electrode 24), which generates heat and heats the feed solution 11. Furthermore, electrolysis of water generates gas around the electrodes (hydrogen gas in the cation chamber 17, and chlorine gas and oxygen gas in the anion chamber 27). The gas moves to the upper part of the sealed space of the feed chamber 12 due to buoyancy. Therefore, gas venting means such as a gas vent valve is appropriately installed in the feed chamber 12, the cation chamber 17, the anion chamber 27, or the discharge line.

[0106] Furthermore, a piezoelectric vibrator (vibration member) that is a piezoelectric member may be installed in supply chamber 12, cation chamber 17, and anion chamber 27. By installing this piezoelectric vibrator, adhesion of particles 42 can be prevented, and therefore the voltage applied to first anode electrode 24A and second anode electrode 24B can be reduced overall. That is, in order to improve particle separation, for example, if 20 V is applied to the anode first electrode 24A and the anode second electrode 24B, by installing a piezoelectric vibrator (vibration member), the applied voltage can be halved to 5 V to the anode first electrode 24A and 10 V to the anode second electrode 24B, thereby reducing the overall applied voltage. As a result, the power consumption of the electrolytic filtration device can be significantly reduced, and electrolysis and heat generation can also be suppressed. In particular, the heat reduction effect is significant when separating heat-sensitive particles or biological matter, which will be described later, as the separation target. Note that it is sufficient to provide a piezoelectric vibrator (excitation member) in at least one location.

[0107] In this embodiment, the diaphragm filter material 13 may be, for example, nanofiber (NF) made of the above-mentioned high dielectric constant material, or filter cloth or filter paper made of a high molecular weight polymer with a high relative dielectric constant and permittivity. This provides the remarkable effect of functioning satisfactorily in the low voltage range and not decreasing the rejection rate even under high flow rate conditions.

[0108] The electrofiltration device of the present invention is not limited to the ion separation described above, but can also be applied to techniques for separating positively charged components similar to cations (e.g., positively charged particles) and negatively charged components similar to anions (negatively charged particles). Here, examples of positively charged particles include some organic substances and some inorganic substances such as alumina, while examples of negatively charged substances include many organic substances and many inorganic substances such as silica. For example, the present invention can be applied to component separation in the fields of life science, sewage treatment, wastewater treatment, etc. In the field of life science, the present invention can be applied to the bioindustry, which cultivates microbial organisms such as cultured cells, microalgae, bacteria, and viruses, as well as to the biopharmaceutical and cosmetics industries, which utilize and apply enzymes, proteins, polysaccharides, lipids, etc. produced in vitro or intracellularly by cultured microbial organisms, and to the beverage industry, which handles brewing, fermentation, juicing, and beverages. In the fields of sewage treatment and wastewater treatment, the present invention can be applied to the separation of biomass particles in aqueous slurries containing difficult-to-filter fine biomass. Alternatively, the present invention can be applied to the concentration and recovery of colloidal particles in colloidal particle slurries in which surface-charged particles are highly dispersed due to electrical repulsion. [Industrial Applicability]

[0109] The present invention can be used in all electrofiltration devices that have improved separation efficiency as electrofiltration characteristics and have high functionality, as well as in methods for manufacturing filter media for electrofiltration devices. [Explanation of symbols]

[0110] 10A~10C Electrolytic filtration equipment 11 Electrolyte solution (supply solution) 11A 1st supply and discharge liquid 11B 2nd supply and discharge liquid 11C 3rd supply and discharge liquid 12 Supply room 12a entrance 12b Supply liquid introduction line 12c 3rd outlet 13 Diaphragm (filter material) 13a pore 13b Surface treatment layer 14 Cathode filter plate electrode 14A Cathode 1st electrode 14B Cathode second electrode 14a hole 14b High dielectric constant coating layer 15 Flat anode electrode 15b High dielectric constant coating layer 16 Cationic liquid (alkaline liquid) 17 Cation Chamber 17a 1st outlet 22 Supply room 24 Anode filter plate electrode 24A Anode 1 24B Anode second electrode 25 Flat cathode electrode 26 Anionic liquid (acidic liquid) 27 Anion Chamber 27a 2nd outlet 50 particles 51 Particle mixed feed liquid 51A Drainage fluid

Claims

1. a supply chamber for supplying a supply liquid containing a positively charged component; a cathode filter plate electrode provided with a filter medium having fine pores for separating positively charged components, and a flat anode electrode, the cathode filter plate electrode being disposed on both sides of the supply chamber; a filtrate chamber into which the filtrate from which the positively charged components have been separated flows, The electrolytic filtration device is characterized in that the filter medium is made of a high dielectric constant material.

2. a supply chamber for supplying a supply liquid containing a negatively charged component; an anode filter plate electrode provided with a filter medium having fine holes for separating negatively charged components, the anode filter plate electrode being disposed on both sides of the supply chamber; and a flat cathode electrode; a filtrate chamber into which the filtrate from which the negatively charged components have been separated flows, The electrolytic filtration device is characterized in that the filter medium is made of a high dielectric constant material.

3. a supply chamber for supplying a supply liquid containing a positively charged component and a negatively charged component; a cathode filter plate electrode provided on each side of the supply chamber and having a filter medium with pores for separating positively charged components; and an anode filter plate electrode provided on each side of the supply chamber and having a filter medium with pores for separating negatively charged components. a cation chamber into which the separated positively charged components flow together with water as a cation solution; an anion chamber into which the separated negatively charged components flow together with water as an anion solution; The electrolytic filtration device is characterized in that the filter medium is made of a high dielectric constant material.

4. The filter material is In a resin polymer liquid made from nanofiber raw materials, 4. The electrolytic filtration device according to claim 1, wherein the electrolytic filtration device is made by dispersing and kneading a high-dielectric-constant material.

5. The filter material is 4. The electrolytic filtration device according to claim 1, wherein a powder of a high dielectric constant material is attached to the surface of the nanofiber yarn.

6. The filter material is On the filtering side of a nanofiber sheet formed from a woven fabric of nanofiber yarn or a nonwoven fabric of nanofiber yarn, 4. The electrolytic filtration device according to claim 1, wherein the electrolytic filtration device is formed by laminating a fine particle powder of a high dielectric constant material as a thin film using a medium.

7. 4. The electrolytic filtration device according to claim 1, wherein a surface treatment layer using fluorine gas is formed on the surface of the filter medium.

8. A cathode filter plate electrode provided with the filter material and a flat anode electrode are provided on the surface thereof.

2. The electrolytic filtration device according to claim 1, wherein a coating layer with a high relative dielectric constant is formed.

9. On the surface of the anode filter plate electrode provided with the filter material and the flat cathode electrode, 3. The electrolytic filtration device according to claim 2, wherein a coating layer with a high relative dielectric constant is formed.

10. On the surface of the cathode filter plate electrode provided with the filter medium and the anode filter plate electrode provided with the filter medium, 4. The electrolytic filtration device according to claim 3, wherein a coating layer with a high relative dielectric constant is formed.

11. 11. The electrolytic filtration device according to claim 8, wherein the high dielectric constant coating layer is subjected to a poling treatment.

12. A method for manufacturing a filter medium for an electrolytic filtration device according to any one of claims 1 to 3, comprising: a step of dispersing and kneading a high dielectric constant material into a resin polymer liquid of nanofiber raw material to obtain a mixed raw material polymer; a spinning step of spinning nanofiber yarn from the mixed raw material polymer; and forming the obtained nanofiber yarn into a sheet by weaving it or forming it into a nonwoven fabric.

13. A method for manufacturing a filter medium for an electrolytic filtration device according to any one of claims 1 to 3, comprising: The method for manufacturing a filter medium for an electric field filtration device is characterized in that the filter medium is made by adhering a powder of a high dielectric constant material to the surface of nanofiber yarns.

14. A method for manufacturing a filter medium for an electrolytic filtration device according to any one of claims 1 to 3, comprising: The filter material is On the filtering side of a nanofiber sheet formed from a woven fabric of nanofiber yarn or a nonwoven fabric of nanofiber yarn, A method for manufacturing a filter medium for an electric field filtration device, characterized by laminating fine particle powder of a high dielectric constant material.

15. A method for manufacturing a filter medium for an electrolytic filtration device according to any one of claims 1 to 3, comprising: The filter material is A method for manufacturing a filter medium for an electrolytic filtration device, the filter medium being made of a high molecular weight polymer made of a high dielectric constant material.

16. A method for manufacturing a filter medium for an electrolytic filtration device according to any one of claims 1 to 3, comprising: The filter material is A method for producing a filter medium for an electrolytic filtration device, comprising coating or impregnating a high molecular weight polymer made of a high dielectric constant material onto the surface of a nanofiber molded body formed into a sheet shape.

17. A method for manufacturing a filter medium for an electrolytic filtration device according to any one of claims 1 to 3, comprising: a step of dispersing and kneading a high molecular weight polymer made of a high dielectric constant material into a resin polymer made of a nanofiber raw material to obtain a mixed raw material polymer; a spinning step of spinning nanofiber yarn from the mixed raw material polymer; and forming the obtained nanofiber yarn into a sheet shape by weaving or forming it into a nonwoven fabric to form a filter medium.

Images