JP7820596B2 - Seawater desalination system and seawater desalination method - Google Patents

Description

The present invention relates to a seawater desalination system and a seawater desalination method.

Patent Document 1 discloses a technology proposed as an ion separation device for separating cations and anions in a solution (electrolyte).

FIG. 16 is a schematic diagram of a conventional electrolyzed water generating device.
In the technology of Patent Document 1, oxidized water and reduced water that constitute electrolyzed water are generated using a three-chamber electrolyzed water generator as shown in Fig. 16. This electrolyzed water generator is composed of an intermediate chamber 1 through which various raw waters such as pure water and tap water and supporting electrolytes such as sodium chloride (NaCl) or potassium chloride (KCl) dissolved in the raw water circulate and flow in and out, a cathode chamber 2 in which a cation exchange membrane 4 and a cathode 5 are disposed as partitions between the intermediate chamber 1 and the cathode chamber 2, and in which cations of the supporting electrolyte (sodium ions (Na ⁺ ) in Fig. 16) dissolve), and an anode chamber 3 in which an anion exchange membrane 6 and an anode 7 are disposed as partitions between the intermediate chamber 1 and the anode chamber 3, and in which anions of the supporting electrolyte (chloride ions in Fig. 16) dissolve.

Using this electrolyzed water generator, raw water with a supporting electrolyte dissolved in it is circulated in the intermediate chamber 1, causing electrolysis. At the same time, the raw water is fed into the cathode chamber 2 and the anode chamber 3, producing reduced water 8 from the cathode chamber 2 and oxidized water 9 containing chloride ions from the anode chamber 3. The physical properties of the reduced water 8 and oxidized water 9 are controlled to produce them, and electrolyzed water is obtained by mixing the appropriate amounts of reduced water 8 and oxidized water 9.

JP 2013-17405 A

However, the electrolyzed water generating device disclosed in Patent Document 1 uses ion exchange membranes to separate ions, but the ion exchange membranes (4, 6) are dedicated membranes that can permeate either cations or anions, respectively, and have the problem that they are almost completely impermeable to water.
Therefore, as a fluid to receive the permeated ions, purified water (H ₂ O) must be separately supplied to the cathode chamber 2 and the anode chamber 3. By supplying this water (purified water), reduced water 8 can be discharged from the cathode chamber 2, and oxidized water 9 containing chloride ions can be discharged from the anode chamber 3.

As such, conventional electrolyzed water generators using ion exchange membranes have the problem that, in order to obtain electrolyzed water, purified water must be separately supplied as carrier water to the cathode chamber 2 and the anode chamber 3.

Therefore, there is a strong demand for technology that can separate ions by passing water through raw water without the need for a separate water supply, such as an electrolytic water generator.

In consideration of the above problems, the present invention provides an ion separation device and ion separation and concentration system that can separate ions by allowing water from raw water (supply liquid) to pass through directly, without the need to separately supply water as in conventional electrolyzed water generation devices.

The seawater desalination system according to the first aspect of the present invention comprises:
a first ion separation device that allows cations in seawater to pass through and blocks anions;
a second ion separation device provided downstream of the first ion separation device, which allows anions in the permeate through which cations have permeated to pass and blocks cations;
The seawater desalination apparatus is provided with a unit including the above components , and
The seawater desalination apparatus comprises:
a supply chamber for supplying seawater containing cations and anions;
a cathode filter plate electrode disposed on both sides of the supply chamber and equipped with a diaphragm having pores for separating cations;
a flat anode filter plate electrode provided with a diaphragm having pores for separating anions;
a cation chamber into which the separated cations flow together with water as a cation liquid;
The cathode filter plate electrode is
a cathode first electrode on the supply chamber side;
a cathode second electrode disposed on the cation chamber side across the diaphragm;
a first power source electrically connected to the anode electrode and the cathode first electrode of the flat plate;
a second power source electrically connected to the cathode first electrode and the cathode second electrode;
The anode filter plate electrode is
an anode first electrode on the supply chamber side;
a second anode electrode disposed on the anion chamber side across the diaphragm;
a third power source electrically connected to the cathode electrode and the anode first electrode of the flat plate;
and a fourth power source electrically connected to the anode first electrode and the anode second electrode.

The seawater desalination system of the second aspect comprises:
In a first aspect, the pretreatment device of the seawater desalination plant includes:
a first pretreatment device provided with a filter for removing impurities from seawater;
a second pretreatment device provided with a hydrophilic polymer adsorbent for adsorbing biopolymers in the seawater from the first pretreatment device;
The present invention is characterized by comprising:

The seawater desalination method of the third aspect comprises:
a first ion separation device that allows cations in seawater to pass through and blocks anions;
a second ion separation device provided downstream of the first ion separation device, which allows anions in the permeate through which cations have permeated to pass and blocks cations;
The seawater desalination system of the first aspect is provided with a seawater desalination apparatus comprising the above as a single unit,
The salinity of the seawater is reduced.

A seawater desalination method according to a fourth aspect includes:
a first ion separation device that allows cations in seawater to pass through and blocks anions;
a second ion separation device provided downstream of the first ion separation device, which allows anions in the permeate through which cations have permeated to pass and blocks cations;
The seawater desalination system of the first aspect is provided with a seawater desalination apparatus comprising the above as a single unit,
The salinity of the seawater is reduced.

1 is a schematic diagram of an ion separation device according to a first embodiment of the present invention. FIG. 1 is a schematic diagram of an ion separation device according to a second embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a third embodiment of the present invention. FIG. 10 is a schematic diagram of another form of an ion separation device according to the third embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a fourth embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a fifth embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a sixth embodiment of the present invention. 10 is a graph showing test results of the ion separation device according to the sixth embodiment of the present invention. 10 is a graph showing test results of the ion separation device according to the sixth embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a seventh embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to an eighth embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device of Test Example 1 of Embodiment 8 according to the present invention. FIG. 10 is a schematic diagram of an ion separation device of Test Example 2 of Embodiment 8 according to the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a ninth embodiment of the present invention. FIG. 10 is a schematic diagram of an ion separation device according to a ninth embodiment of the present invention. FIG. 16 is a schematic diagram of an ion separation device according to a tenth embodiment of the present invention. FIG. 16 is a schematic diagram of another ion separation device according to embodiment 10 of the present invention. 11 is a schematic diagram of an ion separation and concentration system equipped with an ion separation device according to an eleventh embodiment of the present invention. FIG. 10 is a schematic diagram showing the results of confirming the state of ion separation in the ion separator using a BTB reagent. 1 is a schematic diagram of a prior art electrolyzed water generating device. FIG. 19 is a schematic diagram of another ion separation device according to embodiment 11 of the present invention. FIG. 12 is a schematic diagram of an ion separation device according to a twelfth embodiment of the present invention. FIG. 13 is a schematic diagram of an ion separation device according to a thirteenth embodiment of the present invention. FIG. 14 is a schematic diagram of an ion separation device according to a fourteenth embodiment of the present invention. FIG. 15 is a schematic diagram of an ion separation device according to a fifteenth embodiment of the present invention. 16 is a schematic diagram of an ion separation and concentration system equipped with an ion separation device according to a sixteenth embodiment of the present invention. 17 is a schematic diagram of a seawater desalination system including a seawater desalination apparatus according to a seventeenth embodiment of the present invention. FIG.

The present disclosure will be described in detail below with reference to the drawings. Note that the present disclosure is not limited to the following modes for carrying out the invention (hereinafter referred to as embodiments). Furthermore, the components in the following embodiments 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 embodiments 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.

[Embodiment 1]
FIG. 1 is a schematic diagram of an ion separation apparatus according to a first embodiment of the present invention.
The ion separation device 10A according to the first embodiment is a device that separates 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 electrolytic 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.

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 (H ₂ O) dissociates into its ions and is an electrolyte, and in the electrolyte chamber solution, sodium chloride (NaCl) is completely dissociated into water and exists in an ionic state as positive sodium ions (Na ⁺ ) and negative chloride ions (Cl ^- ).

In this embodiment, sodium chloride (NaCl) is used as an example, but the present invention is not limited to this.
As shown in FIG ^. 1, the ion separation device 10A of embodiment 1 comprises an electrolyte solution supply chamber (hereinafter referred to as the "supply chamber") 12 that supplies an electrolyte solution (NaCl+H ₂ O: hereinafter referred to as the "supply liquid") 11 containing cations (Na ⁺ ) and anions (Cl ^- ), cathode filter plate electrodes 14 arranged on both sides of the supply chamber 12 and equipped with diaphragms (filter material) 13 that separate the cations (Na ⁺ ), a flat anode electrode 15, and a cation chamber 17 into which the separated cations (Na + ) flow together with water as a cation liquid (hereinafter also referred to as the "alkaline liquid") 16.
Here, 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 plate) 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 may be made of, for example, cellulose, but the present invention is not limited to this.

The ion separation device 10A further includes a first power supply 41 electrically connected to the flat anode electrode 15 and the cathode first electrode 14A, and a second power supply 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), the cathode first electrode 14A is at a second potential (V2), and the flat anode electrode 15 is at a third potential (V3).

In this embodiment, the first power supply 41 and the second power supply 42 are set to V1=-20V, V2=-15V, and V3=+15V.
The potentials supplied from the first power source 41 and the second power source 42 are set to V3 > V2 > V1, so that the absolute value of the potential of the cathode electrode increases as it moves away from the supply chamber 12 (|V1| > |V2|).

The electrode configuration is not limited to that shown in Figure 1. Alternatively, the cathode first electrode 14A can be earthed, the cathode first electrode 14A can be used as a reference electrode, the potential (V2) of the cathode first electrode 14A can be set to 0 V, the potential (V1) of the cathode second electrode 14B can be set to -10 V, and the potential (V3) of the flat anode electrode 15 can be set to +10 V, and the absolute value of the voltages can be changed without changing the potential difference between them.

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

Furthermore, the cathode electric field Ec generated between the first cathode electrode 14A and the second cathode electrode 14B exerts a force that draws cations (Na ⁺ ) and positively charged water molecules from the supply chamber 12 toward the cation chamber 17. An electroosmotic flow occurs in which the cations (Na ⁺ ) and positively charged water molecules are drawn toward the cation chamber 17 (see arrows F1 and F2 in FIG. 1 ). As a result, the water in the supply chamber 12 moves faster than it would move to the cation chamber 17 simply under the filtration pressure of a pump or the like. This increases the amount of water moving from the supply chamber 12 to the cation chamber 17 per unit time.

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.
The first supply/discharge liquid 11A from which the cations have been separated in the supply chamber 12 has a reduced cation concentration, and is discharged to the outside from an outlet (not shown) of the supply chamber 12 due to filtration pressure.

Here, the filtration pressure applied 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, between 0.005 MPa and 0.5 MPa, and preferably between 0.02 MPa and 0.1 MPa.

The cathode filter plate electrodes 14 (cathode first electrode 14A, cathode second electrode 14B) have multiple holes 14a that penetrate in the left-right direction in the figure. Water in the supply liquid 11 moves through the holes 14a in the electrodes 14.

In addition, 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 anode electrode 15. Examples of the galvanic corrosion prevention layer include an insulating coating layer and a conductive precious metal layer. Materials for the galvanic corrosion prevention layer include, but are not limited to, titanium, aluminum, magnesium, and tantalum. Materials for the conductive precious metal layer include, but are not limited to, platinum, gold, and palladium. For an insulating coating layer, the thickness of the galvanic corrosion prevention layer is preferably, for example, approximately 5 μm to 30 μm, more preferably, approximately 5 μm to 10 μm. For a conductive precious metal layer such as platinum, gold, or palladium, the thickness is preferably, for example, approximately 0.5 μm to 10 μm, more preferably, approximately 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 anode electrode 15. Furthermore, because the cathode filter plate electrode 14 and the flat anode electrode 15 have an insulating coating layer, they do not come into contact with the liquid that makes up the supply liquid 11. As a result, even if a potential is applied to the cathode filter plate electrode 14 and the flat anode electrode 15, electrolysis is unlikely to occur between the liquid and the surfaces of the cathode filter plate electrode 14 and the flat anode electrode 15.

The cathode first electrode 14A faces the flat anode electrode 15 across the supply chamber 12. The distance D1 between the cathode first electrode 14A and the flat anode first electrode 15 is, for example, 0.1 mm or more and 100 mm or less, and more preferably 0.1 mm or more and 40 mm or less.

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

The 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 the diaphragm 13. As a result, the supply liquid 11 can pass freely through the diaphragm 13 when pumped into the supply chamber 12 by a pump.

In contrast, when negative chlorine ions (Cl ⁻ ) approach the cathode first electrode 14A on the cathode side, the negative electrode and the negative ions are repelled by Coulomb's repulsive force, and the negative ions cannot pass through the cathode first electrode 14A. Conversely, when positive ions (Na ⁺ ) approach the anode electrode 15 side of the anode plate, the positive electrode and the positive ions are repelled by Coulomb's repulsive force.

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 for example, a nonwoven fabric using fibers such as PP (polypropylene), PE (polyethylene), NY (nylon), or cellulose may be used.
Here, by placing the diaphragm 13 having a dielectric effect between the first cathode electrode 14A and the second cathode electrode 14B, the force of the cathode electric field Ec acting between the first cathode electrode 14A and the second cathode electrode 14B increases.
The diameter of the fine holes 13a is preferably, for example, 0.2 mm or less.
The diaphragm 13 disposed between the cathode first electrode 14A and the cathode second electrode 14B may or may not be in contact with each other.
Here, the cathode filter plate electrode 14 equipped with this diaphragm 13 functions as an "ion separation membrane."

Next, using Figure 1, we will explain an example of separating cations by supplying a sodium chloride solution as the supply liquid 11 into the supply chamber 12.

As described above, the ions in supply chamber 12 are dissociated into cations (sodium ions: Na ⁺ ) and anions (chlorine ions: Cl ⁻ ).
Sodium ions (Na ⁺ ), which are cations, are attracted to negative cathode first electrode 14A disposed in supply chamber 12. As a result, the sodium ions (Na ⁺ ), which are cations, are attracted to the cathode first electrode 14A, and as a result, the sodium ions (Na ⁺ ) permeate while water (H ₂ O) also permeates.

In contrast, chloride ions (Cl ^- ) are anions, and therefore are blocked by the cathode first electrode 14A on the cathode side and cannot pass through the cathode first electrode 14A. FIG. 1 illustrates the rebounding behavior of chloride ions (Cl ^- ). Therefore, chloride ions (Cl ^- ) are concentrated in the supply chamber 12. As a result, the first supply/discharge liquid 11A discharged from the supply chamber 12 has a reduced concentration of cations (Na ⁺ ) and chloride ions (Cl ^- ) concentrated.

The present invention is characterized in that, in addition to the permeation of cations (Na ⁺ ), water also permeates the diaphragm 13 constituting the cathode filter plate electrode 14. As a result, the permeated water acts as carrier water for cations (Na ⁺ ), eliminating the need to separately supply purified water or other water.
The cation exchange membranes and anion exchange membranes of the prior art are only able to selectively separate ions, allowing little or no water to pass through, and therefore require the separate supply of purified water or other water as carrier water.

As a result, according to the ion separation device 10A, a cationic liquid (alkaline liquid) 16 in which the cations Na ⁺ have been transferred can be obtained in the cation chamber 17.

The above-mentioned cathode filter plate electrode 14 may be configured as an integrated member including the cathode first electrode 14A, the cathode second electrode 14B, and the diaphragm 13, or the diaphragm 13 may be configured as a separate member.

[Embodiment 2]
FIG. 2 is a schematic diagram of an ion separation device according to the second embodiment.
The same components as those in the first embodiment are denoted by the same reference numerals and will not be described again. 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 ion separation device 10B of this embodiment is a device that separates anions dissociated in a solvent (polar solvent; for example, water).

As shown in Figure 2, the ion separation device 10B includes a supply chamber 12 that supplies a supply liquid 11 containing cations (Na ⁺ ) and anions (Cl ^- ), anode filter plate electrodes 24 arranged on both sides of the supply chamber 12 and equipped with diaphragms 13 that separate the anions (Cl ^- ), a flat cathode electrode 25, and an anion chamber 27 into which the separated anions (Cl ^- ) flow together with water as an anion liquid (hereinafter also referred to as "acid liquid") 26.

Here, the anode filter plate electrode 24 is composed of a first anode electrode 24A and a second anode electrode 24B, and a diaphragm 13, an insulator with fine holes, is sandwiched between the first anode electrode 24A and the second anode electrode 24B. This diaphragm 13 is composed 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.

The ion separation device 10B further includes a third power supply 43 electrically connected to the flat-plate 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.

Here, the electrode configuration is such that the anode second electrode 24B is at a first potential (V11), the anode first electrode 24A is at a second potential (V12), and the flat cathode electrode 25 is at a fourth potential (V4).
In this embodiment, the third power supply 43 and the fourth power supply 44 are set so that V11=+20V, V12=+15V, and V4=-15V.
The potentials supplied from the third power source 43 and the fourth power source 44 are set to satisfy the relationship V4 < V12 < V11, so that the absolute value of the potential of the anode electrode increases as it moves away from the supply chamber 12 (|V11| > |V12|).

An example in which a sodium chloride solution (NaCl+H ₂ O) is placed in the supply chamber 12 as the supply liquid 11 will be described.
As described above, the ions in supply chamber 12 are dissociated into cations (sodium ions: Na ⁺ ) and anions (chlorine ions: Cl ⁻ ). Anions, such as chloride ions (Cl ⁻ ), are attracted to anode first electrode 24A disposed in supply chamber 12. As a result, chloride ions are allowed to pass through while water (H ² _O ) also passes through.

In contrast, sodium ions (Na ⁺ ) are positive ions and are therefore blocked by the anode first electrode 24A (the sodium ions (Na ⁺ ) bounce back in FIG. 2 ), preventing them from passing through the anode first electrode 24A. As a result, the sodium ions (Na ⁺ ) are concentrated in the supply chamber 12. As a result, the second supply/discharge liquid 11B discharged from the supply chamber 12 has a reduced concentration of chloride ions (Cl ⁻ ) and is in a state in which the positive ions (Na ⁺ ) are concentrated.

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

The holes 24a in the anode first electrode 24A and the anode second electrode 24B connect 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. Note that 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.

As described in the first embodiment, the present invention is characterized in that water permeates along with the anions (Cl ^- ). As a result, the permeated water acts as carrier water for the anions (Cl ^- ), and there is no need to separately supply purified water or other water. As a result, there is no need to separately supply purified water or other water as carrier water for the permeated anions (Cl ^- ).
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.

As a result, an anion liquid (acid liquid) 26 in which the anions Cl ⁻ have been transferred can be obtained in the anion chamber 27 .
In addition, a diaphragm 13 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.
The anode filter plate electrode 24 may be configured as an integrated member including the first anode electrode 24A, the second anode electrode 24B, and the diaphragm 23, or the diaphragm 23 may be configured as a separate member.

[Embodiment 3]
Fig. 3A is a schematic diagram of an ion separation device of embodiment 3. Fig. 3B is a schematic diagram of an ion separation device of another form of embodiment 3. Note that the same components as those in embodiments 1 and 2 are denoted by the same reference numerals and descriptions thereof will be omitted.
As shown in FIG. 3A, the ion separation device 10C-1 of this embodiment is a combination of the ion separation device 10A of embodiment 1 and the ion separation device 10B of embodiment 2, and separates cations and anions from a supply liquid containing both ions (cations and anions) to obtain an alkaline liquid 16 and an acidic liquid 26.
As shown in FIG. 3A, the ion separation device 10C-1 of embodiment 3 comprises an electrolyte solution supply chamber (hereinafter referred to as the "supply chamber") 12 that supplies a supply liquid 11 of an electrolyte solution (e.g., NaCl solution) containing cations and anions, a cathode filter plate electrode 14 arranged on both sides of the supply chamber 12 and equipped with a diaphragm (filter paper) 13 that separates cations (Na ⁺ ), an anode filter plate electrode 24 equipped with a diaphragm 13 that separates anions (Cl ⁻ ), a cation chamber 17 into which the separated cations (Na ⁺ ) flow together with water as a cation liquid (alkaline liquid) 16, and an anion chamber 27 into which the separated anions (Cl ⁻ ) flow together with water as an anion liquid (acidic liquid) 26.

The ion separation device 10C-1 also has a first power supply 41 electrically connected to the cathode first electrode 14A and the anode first electrode 24A, a second power supply 42 electrically connected to the cathode first electrode 14A and the cathode second electrode 14B, and a third power supply 43 electrically connected to the anode first electrode 24A and the anode second electrode 24B.
In this embodiment, the diaphragm 13 in the cathode filter plate electrode 14 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.

Next, using Figure 3A, we will explain an example of separating cations and anions by supplying sodium chloride solution as the supply liquid 11 into the supply chamber 12.

As described above, the ions in supply chamber 12 are dissociated into cations (sodium ions: Na ⁺ ) and anions (chlorine ions: Cl ⁻ ).
Sodium ions (Na ⁺ ), which are cations, are attracted to negative cathode first electrode 14A disposed in supply chamber 12. As a result, the sodium ions (Na ⁺ ), which are cations, are attracted to the cathode first electrode 14A, and as a result, the sodium ions (Na ⁺ ) permeate while water (H ₂ O) also permeates.

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.

The present invention is characterized in that, in addition to the permeation of cations (Na ⁺ ), water also permeates the diaphragm 13 constituting the cathode filter plate electrode 14. As a result, there is no need to separately supply purified water or other water to the cation chamber 17 as carrier water for the permeated cations (Na ⁺ ).

Furthermore, chloride ions (Cl ⁻ ), which are anions, are attracted to the anode filter plate electrodes (anode first electrode 24 A, anode second electrode 24 B) 24 disposed in the supply chamber 12 opposite the cathode filter plate electrode 14 .
When an anion, chlorine ion (Cl ⁻ ), is attracted, the chlorine ion permeates while water (H ₂ O) also permeates.

In contrast, sodium ions (Na ⁺ ) are cations and are therefore blocked by the anode first electrode 24A and cannot pass through the anode first electrode 24A.

As a result, sodium ions (Na ⁺ ) are concentrated in the cation chamber 17. Furthermore, chloride ions (Cl ⁻ ) are concentrated in the anion chamber 27. As a result, the third supply/discharge liquid 11C discharged from the supply chamber 12 has a reduced content of sodium ions (Na ⁺ ) and chloride ions (Cl ⁻ ).

Here, water as well as anions (Cl ⁻ ) permeate into the cation chamber 17. As a result, the permeated water acts as carrier water for the anions (Cl ⁻ ), so there is no need to separately supply purified water or other water.

Note that ion exchange membranes used in conventional ion separation technology are barely permeable to water and only function to separate ions. In contrast, when producing alkaline solution 16 and acidic solution 26 using the ion separation device 10C of this embodiment, there is no need to supply purified water as carrier water.

As described above, according to the ion separation device 10C-1 of this embodiment, in the ionic state of the supply liquid 11 supplied into the supply chamber 12 (a mixture of sodium ions (Na ⁺ ) and chloride ions (Cl ^- ): pH = 7.0), sodium ions (Na ⁺ ) permeate the cathode filter plate electrode 14 located on the left side of the supply chamber 12, and the sodium ions (Na ⁺ ) are concentrated in the cation chamber 17. At the same time, chloride ions (Cl ^- ) permeate the anode filter plate electrode 24 located on the right side of the supply chamber 12, and the chloride ions (Cl ^- ) are concentrated in the anion chamber 27.

The separation of cations and anions in this ion separator 10C-1 was confirmed using pH and a BTB reagent. Here, a 0.05% aqueous solution of sodium chloride (NaCl) was used as the feed liquid 11, and the pH of the feed liquid was adjusted with a carbonate buffer to pH 7.0.
At the same time, the pH state in each chamber was visualized by coloring using BTB (bromothymol blue; BTB) reagent.

As a result of this confirmation, it was found that the ionic state of the supply liquid 11 supplied to the supply chamber 12 (a mixture of sodium ions (Na ⁺ ) and chlorine ions (Cl ^- ): pH = 7.0) was such that, as a result of ion separation, the pH of the alkaline liquid 16 discharged from the cation chamber 17 became 11.8, and the pH of the acidic liquid 26 discharged from the anion chamber 27 became 2.4.

Furthermore, as a result of testing with the BTB reagent, the feed solution 11 (pH = 7.0) supplied to the feed chamber 12 was green, but the alkaline solution 16 (pH = 11.8) in the cation chamber 17 changed to blue, and the acidic solution 26 (pH = 2.4) in the anion chamber 27 changed to yellow. Furthermore, in a flame color reaction test using a copper wire, the alkaline solution 16 changed to orange due to Na ions, and the acidic solution 26 changed to green due to copper chloride (CuCl ₂ ). Furthermore, in each flame color reaction test, it was confirmed that ion separation was reliably achieved.

As a result, the circulating liquid, which is the third supply/discharge liquid 11C discharged from the supply chamber 12, has a reduced sodium ion (Na ⁺ ) content and a reduced chloride ion (Cl ⁻ ) content (pH=4.5).

A schematic diagram of the results of confirmation using this BTB reagent is shown in FIG.
Figure 15 is a schematic diagram showing the results of confirming the state of ion separation in the ion separator using a BTB reagent. In Figure 15, "A" in the upper row shows the color tone of the BTB reagent. "B" in the middle row shows the state of color tone change in the supply chamber 12, which has a cation chamber 17 and an anion chamber 27 on both sides. "C" in the lower row shows the state of color tone of the supply liquid 11.

In 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 acts as ion carrier water and passes through the cathode filter plate electrode 14 and the anode filter plate electrode 24, eliminating the need to separately add water (such as purified water) as ion carrier water, as in the conventional method.

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 supply liquid 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 supply chamber 12 due to buoyancy. Therefore, gas venting means such as a gas vent valve are appropriately installed in the supply chamber 12, cation chamber 17, anion chamber 27, or discharge line.

Furthermore, as shown in FIG. 3B, the ion separation device 10C-2 has piezoelectric vibrators (vibration members) 80, which are piezoelectric members, installed in the supply chamber 12, cation chamber 17, and anion chamber 27. By installing these piezoelectric vibrators (vibration members) 80, adhesion of particles suspended in the supply liquid 11 can be prevented. This allows the voltage applied to the first anode electrode 24A and the second anode electrode 24B to be lower overall than when the piezoelectric vibrators (vibration members) 80 are not installed.

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) 80, 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 ion separation 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 the piezoelectric vibrator (vibration member) 80 in at least one location.

[Embodiment 4]
FIG. 4 is a schematic diagram of an ion separation device according to a fourth embodiment.
The same components as those in the first to third embodiments are denoted by the same reference numerals and the description thereof will be omitted.
The ion separation device 10D of this embodiment 4 has two sets of electrodes (cathode filter plate electrodes, anode filter plate electrodes) (14-1, 14-2, 24-1, 24-2), and two sets of cation chambers 17 and two sets of anion chambers 27 (17-1, 17-2, 27-1, 27-2).

The potentials of the cathode electrodes 14A-1, 14B-1, 14A-2, and 14B-2 are set to −15 V, −20 V, −30 V, and −35 V, respectively, by a power supply (not shown). The potentials of the anode electrodes 24A-1, 24B-1, 24A-2, and 24B-2 are set to +15 V, +20 V, +30 V, and +35 V, respectively.
The absolute values of the potentials of the cathode electrodes (14A-1, 14B-1, 14A-2, 14B-2) and anode electrodes (24A-1, 24B-1, 24A-2, 24B-2) are set to increase with increasing distance from supply chamber 12.

As shown in Figure 4, the ion separation device 10D of this embodiment 4 comprises a supply chamber 12 that supplies an electrolyte solution (e.g., NaCl solution: pH 7.0) supply liquid 11 containing cations and anions, cathode filter plate electrodes 14-1, 14-2 arranged on both sides of the supply chamber 12 and equipped with a diaphragm (filter material) 13 that separates cations, anode filter plate electrodes 24-1, 24-2 equipped with a diaphragm (filter material) 13 that separates anions, cation chambers 17 (17-1, 17-2) into which separated cations (Na ⁺ ) flow together with water as a cation liquid (alkaline liquid) 16, and anion chambers 27 (27-1, 27-2) into which separated anions (Cl ^- ) flow together with water as an anion liquid (acidic liquid) 26.

In this embodiment, the second cation chamber 17-2 and the second anion chamber 27-2 also serve as discharge chambers for discharging the alkaline solution 16 and the acid solution 26, respectively, and are equipped with discharge holes 17a and 27a, respectively. The supply chamber 12 also has a supply hole 12a and a discharge hole 12c. The discharged liquid is a circulating liquid.

As a result, the alkaline solution 16 with an increased cation concentration and a raised pH is discharged from the discharge hole 17a of the second cation chamber 17-2.
On the other hand, the acidic solution 26 with an increased anion concentration and a decreased pH is discharged from the discharge hole 27a of the second anion chamber 27-2.

In this embodiment, the ion separation device 10D has two sets of electrodes (cathode filter plate electrode, anode filter plate electrode) (14-1, 14-2, 24-1, 24-2), and two sets of cation chambers 17 and anion chambers 27 (17-1, 17-2, 27-1, 27-2), thereby increasing the ion separation efficiency.
In the present invention, the installation of each cation chamber 17 and anion chamber 27 is not limited to two sets, but may be three sets (17-1, 17-2, 17-3, 27-1, 27-2, 27-3) or four sets (17-1, 17-2, 17-3, 17-4, 27-1, 27-2, 27-3, 27-4) as needed.

The ion separation devices 10A to 10D described above can be applied to any technical field that separates ions in an electrolyte. In addition to replacing ion exchange membranes and ion exchange resins, they can also be used in technical fields that separate ions, such as seawater desalination (desalination) devices and artificial dialysis devices.

[Embodiment 5]
FIG. 5 is a schematic diagram of an ion separation device according to a fifth embodiment.
As shown in FIG. 5 , the ion separation device 10E of the fifth embodiment includes the ion separation device 10A of the first embodiment, a supply tank 55 that supplies an electrolyte solution (supply liquid 11) containing cations, a supply line _L1 that supplies the supply liquid 11 from the supply tank 55 to the supply chamber 12 via a supply pump P, a circulation line _L2 that circulates the first supply/discharge liquid 11A from the supply chamber 12 to the supply tank 55, and an alkali line _L3 that discharges the alkaline solution 16 from the cation chamber 17 to the alkali tank 56.

The ion separation device 10E of this embodiment 5 continuously supplies the supply liquid 11 from the supply tank 55 into the supply chamber 12, thereby separating cations into the cation chamber 17, and by circulating the liquid within the supply chamber 12, it is possible to continuously obtain a cation liquid (alkaline liquid) 16 in the alkaline tank 56.
Furthermore, by installing the ion separation device 10B of the second embodiment in place of the ion separation device 10A, an anion liquid (acid liquid) can be obtained.

[Embodiment 6]
FIG. 6 is a schematic diagram of an ion separation device according to a sixth embodiment.
As shown in FIG. 6, the ion separation device 10F of the sixth embodiment includes the ion separation device 10D of the fourth embodiment, a supply tank 55 for supplying an electrolyte solution (feed liquid 11) containing cations, a supply line L ₁ for supplying the feed liquid 11 from the supply tank 55 to the supply chamber 12 via a supply pump P-1, a circulation tank 57 for temporarily storing the first supply discharge liquid 11A from the supply chamber 12 to circulate it to the supply chamber 12, an alkaline line L ₃ for discharging the alkaline solution 16 from the cation chamber 17 to the alkaline tank 56 by the supply pump P-2, a supply line L 4 for supplying the first supply discharge liquid 11A from the supply chamber 12 to the circulation tank 57, and an acid line L ₅ for discharging the acid solution 26 from the anion chamber 27 via the supply pump P- ₃ to the acid solution tank 58.
A pressure relief valve (not shown) is provided in the circulation line _L4 to regulate the pressure (for example, to about 0.03 MPa).

By using the ion separation device 10F of this embodiment 6, cation liquid (alkaline liquid) 16 can be continuously obtained in the alkaline tank 56, and anion liquid (acid liquid) 26 can be continuously obtained in the acid liquid tank 58.

Here, the test results of ion separation using the ion separation device 10F of the sixth embodiment shown in FIG. 6 and an aqueous solution of sodium nitrate (NaNO ₃ ) as the feed liquid 11 are shown in FIG. 7 (FIGS. 7A and 7B).
The separation target was a 0.05% aqueous solution of NaNO ₃ , whose pH was adjusted to 7.0 with a carbonate buffer. The evaluation method involved measuring the ion concentration with a Na ⁺ /NO ₃ ^- ion meter.

As shown in Figure 7A, the separation efficiency of Na ions (cations) was 95.4% (20 min), 88.5% (40 min), and 83.1% (60 min). As shown in Figure 7B, the separation efficiency of NO ions ( _anions ) was 96.6% (20 min), 94.9% (40 min), and 94.3% (60 min).
The results of FIGS. 7A and 7B show that the ion separation device of this embodiment can effectively separate cations and anions.

[Embodiment 7]
8 is a schematic diagram of an ion separation device according to embodiment 7. Note that the same components as those in the above-described embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

The ion separation devices 10A to 10F in embodiments 1 to 6 describe techniques for separating cations or anions in an electrolyte solution, but the ion separation device of the present invention is not limited to this.

The ion separation device 10G of embodiment 7 has the same configuration as the ion separation device 10C of embodiment 3 (see Figure 3) described above, but separates particles 50 as well as ions from a particle-mixed supply liquid 51 in which particles (Ptcl ^- indicated by "●" in the figure) 50 are mixed in the supply liquid supplied to the supply chamber 12.
Since cations (e.g., Na ions) and anions (e.g., chloride ions) are separated in the same manner as described above, the explanation of the ion separation device 10E of this embodiment will focus particularly on the separation of particles 50.

As shown in FIG. 8, the supply chamber 12 of the ion separation device 10G is provided with an inlet 12a for introducing particle-containing supply liquid 51, a supply liquid introduction line 12b connected to the inlet 12a and equipped with a supply pump P, a third outlet 12c for discharging discharge liquid 51A from which particles 50, cations, and anions have been separated, and an outlet line 12d connected to the third outlet 12c.

The cation chamber 17 of the ion separation device 10G is provided with a first outlet 17a for discharging the cation liquid 16 and a first outlet line 17b connected to the first outlet 17a. The anion chamber 27 of the ion separation device 10G is provided with a second outlet 27a for discharging the concentrate 65 containing the anion liquid and a second outlet line 27b connected to the second outlet 27a.

The cathode first electrode 14A faces the anode first electrode 24A across the supply chamber 12. The distance D1 between the cathode first electrode 14A and the anode first electrode 24A is a distance that allows the particles 50 in the particle-containing supply liquid 51 to move toward the anode first electrode 24A, and is, for example, 0.1 mm or more and 100 mm or less, more preferably 0.1 mm or more and 20 mm or less.

In addition, the pore diameter 13a of the diaphragm 13 is large enough to allow the particles 50 in the particle-containing supply liquid 51 to move toward the anode first electrode 24A and the anode second electrode 24B.

Regarding the method of operating the ion separation device 10G, first, the supply pump P is driven to supply the particle-mixed supply liquid 51 to the supply chamber 12. The supply pump P is continuously driven to continuously supply the particle-mixed supply liquid 51. The pressure produced by the supply pump P is set so that the pressure (gauge pressure) in the sealed space S of the supply chamber 12 is higher than atmospheric pressure, for example, between 0.005 MPa and 0.5 MPa, and preferably between 0.02 MPa and 0.1 MPa.

The pressure downstream of the first discharge line 17b and the second discharge line 27b is adjusted to approximately atmospheric pressure by a pressure regulating valve (not shown). This causes pressure (hereinafter referred to as filtration pressure) acting in the sealed space S from the first supply port 12a (supply chamber 12) toward the cation chamber 17 and the anion chamber 27.

The cathode first potential V1 supplied from the cathode first power supply 61 to the cathode first electrode 14A is set to -20 V. The cathode second potential V2 supplied from the cathode second power supply 62 to the cathode second electrode 14B is set to -30 V. In other words, the cathode power supply supplies the cathode electrodes with cathode potentials (V1, V2) of the same polarity as the polarity (negative) of the particles 50. Furthermore, the absolute value of the cathode potential supplied from the cathode power supply increases with increasing distance from the supply chamber 12 (|V2| > |V1|).

The anode first potential V11 supplied from the anode first power supply 63 to the anode first electrode 24A is set to +20 V. The anode second potential V12 supplied from the anode second power supply 64 to the anode second electrode 24B is set to +30 V. In other words, the anode power supply supplies the anode electrodes with anode potentials (V11, V12) of a polarity different from the polarity (negative) of the particles 50. Furthermore, the absolute value of the anode potential supplied from the anode power supply increases with increasing distance from the supply chamber 12 (|V12| > |V11|).

According to the operating method described above, when particle-mixed supply liquid 51 is supplied to supply chamber 12, particles 50 contained in particle-mixed supply liquid 51 are subjected to a repulsive force from cathode first electrode 14A, which is charged with the same polarity (see arrow A1 in Figure 8). Furthermore, particles 50 are subjected to an attractive force from anode first electrode 24A, which is charged with the opposite polarity (see arrow B1 in Figure 8). This causes particles 50 in supply chamber 12 to move toward anode first electrode 24A.

The particle-mixed supply liquid 51 (particle-mixed supply liquid 51 with a high concentration of particles 50) near the first anode electrode 24A passes through the holes 24a of the first anode electrode 24A and the holes 24a of the second anode electrode 24B due to filtration pressure, and the particles 50 move to the anion chamber 27 (see arrow F4 in Figure 8). Furthermore, as the particle-mixed supply liquid 51 passes through the first anode electrode 24A and the second anode electrode 24B, the proportion of water decreases and the proportion of particles 50 increases, resulting in a concentrate 65. Details are explained below.

As a result, the positively charged water molecules move at a slower rate than when they move to the anion chamber 27 simply due to filtration pressure. As a result, the amount of water passing between the anode first electrode 24A and the anode second electrode 24B per unit time decreases. As a result, the proportion of water contained in the particle-mixed supply liquid 51 that has moved to the anion chamber 27 is smaller than that of the particle-mixed supply liquid 51 near the anode first electrode 24A.

Furthermore, the anode electric field Ea between the first anode electrode 24A and the second anode electrode 24B exerts an attractive force that draws the negatively charged particles 50 from the first anode electrode 24A toward the second anode electrode 24B (see arrow F4 in FIG. 8 ). That is, the particles 50 are subjected to an attractive force from the electric field when passing between the first anode electrode 24A and the second anode electrode 24B. This causes the particles 50 to move faster than they would if they were simply subjected to filtration pressure and moved to the anion chamber 27.
As a result, the amount of particles 50 passing between the first anode electrode 24A and the second anode electrode 24B per unit time increases, and therefore the ratio of particles 50 per unit volume contained in the particle-mixed supply liquid 51 that has moved to the anion chamber 27 becomes higher than that of the particle-mixed supply liquid 51 in the vicinity of the first anode electrode 24A.

In this way, the particle-containing supply liquid 51 becomes more concentrated with particles 50 as it passes between the first anode electrode 24A and the second anode electrode 24B, becoming a concentrate 65 containing concentrated particles and anionic liquid. This concentrate 65 then passes through the second outlet 27a and is discharged from the second discharge line 27b due to filtration pressure.

Meanwhile, particle-mixed supply liquid 51 with a low concentration of particles 50 remains near the cathode first electrode 14A in the supply chamber 12. This particle-mixed supply liquid 51 passes through the holes 14a in the cathode first electrode 14A and the holes 14a in the cathode second electrode 14B due to filtration pressure and moves to the cation chamber 17 (see arrow F2 in Figure 8).

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 exerts a repulsive force that inhibits the movement of negatively charged particles 50 from the supply chamber 12 to the cation chamber 17. This inhibits the particles 50 from moving to the cation chamber 17.

In addition, the cathode electric field Ec generated between the cathode first electrode 14A and the cathode second electrode 14B exerts a force that draws positively charged water molecules from the supply chamber 12 toward the cation chamber 17. An electroosmotic flow occurs in which positively charged water molecules are drawn toward the cation chamber 17 (see arrow F2 in Figure 8). Therefore, the water in the supply chamber 12 moves faster than it would if it were simply moving to the cation chamber 17 under filtration pressure. Therefore, the amount of water moving per unit time from the supply chamber 12 to the cation chamber 17 increases.

Then, the cation liquid 16, which is the water (filtrate from which the particles 50 have been separated) that has moved to the cation chamber 17, is discharged from the first outlet 17a due to filtration pressure.

As mentioned above, much of the water contained in the particle-containing supply liquid 51 moves toward the cation chamber 17. In other words, the volume of water that moves per unit time from the supply chamber 12 to the cation chamber 17 or the anion chamber 27 is greater in the cation chamber 17. Therefore, the flow rate ratio discharged from the first outlet 17a and the second outlet 27a is set to, for example, 9:1 (e.g., 10-fold concentration) using the first valve 17c and the second valve 27c, and adjusted so that a large amount of water is discharged from the first outlet 17a. As a result, a large amount of water is continuously discharged as filtrate from the first outlet 17a. Furthermore, a concentrate 65 containing concentrated particles 50 is continuously discharged from the second outlet 27a.

In this embodiment, the flow rate is set to, for example, 9:1 (e.g., 10x concentrated), but by adjusting the flow rate of the metering pump, the flow rate can also be appropriately set to, for example, 2:1 (e.g., 3x concentrated).

As described above, the particle-mixed supply liquid 51 contains cations (Na ions) and anions (Cl ions), so the cations and anions are separated, and alkaline liquid 16 and acidic liquid 26 are discharged from the cation chamber 17 and the anion chamber 27. Since the particle-mixed supply liquid 51 contains particles 50, particle separation also occurs at the same time.

[Embodiment 8]
FIG. 9 is a schematic diagram of an ion separation device according to the eighth embodiment.
The same components as those in the first to seventh embodiments are denoted by the same reference numerals and their description will be omitted.

The ion separation device of the present invention can separate cations or anions in an electrolyte, as well as ions even when charged particles are present in the electrolyte.

In this embodiment, a sodium hydroxide (NaOH) aqueous solution is used as the supply liquid, and the explanation will be given using an example of a particle-mixed supply liquid 51 in which particles (marked with "●" in the figure) 50 are mixed in this sodium hydroxide aqueous solution, but the present invention is not limited to this.
As shown in Figure 9, the ion separation device 10H of embodiment 8 comprises a supply chamber 12 that supplies a particle-mixed supply liquid 51 containing cations (Na ⁺ ), anions (OH ^- ), and particles 50, a cathode filter plate electrode 14 arranged on both sides of the supply chamber 12 and equipped with a diaphragm (filter material) 13 that separates the cations (Na ⁺ ), a flat anode electrode 15, and a cation chamber 17 into which the separated cations (Na ⁺ ) flow together with water as a cation liquid (hereinafter also referred to as "alkaline liquid") 16.

In addition, the ion separation device 10H of embodiment 8 further includes a supply tank 55 that supplies the particle-mixed supply liquid 51 to the supply chamber 12, an alkaline tank 56 that receives the alkaline liquid 16, a supply line _L1 that supplies the particle-mixed supply liquid 51 from the supply tank 55 to the supply chamber 12 via a supply pump P, a circulation line _L2 that circulates the discharge liquid 51B from the supply chamber 12 to the supply tank 55, and an alkaline line _L3 that discharges the alkaline liquid 16 from the cation chamber 17 to the alkaline tank 56.
Here, the cathode filter plate electrode 14 is composed of a cathode first electrode 14A and a cathode second electrode 14B, each having pores 14a, and further, a diaphragm 13, which is an insulator having pores 13a, is sandwiched between the cathode first electrode 14A and the cathode second electrode 14B.

Next, using Figure 9, we will explain an example of supplying a particle-mixed supply liquid 51 containing cations (Na ⁺ ), anions (OH ^- ), and negatively charged particles (●(Ptcl ^- )) 50 into the supply chamber 12 as a supply liquid and separating the cations and particles 50.

As described above, the ions in supply chamber 12 are dissociated into cations (sodium ions: Na ⁺ ) and anions (hydroxyl ions: OH ⁻ ).
Sodium ions (Na ⁺ ), which are cations, are attracted to the negative cathode first electrode 14A disposed in the supply chamber 12. As a result, the sodium ions (Na ⁺ ), which are cations, are attracted to the negative cathode first electrode 14A, and as a result, the sodium ions (Na ⁺ ) permeate while water (H ₂ O) also permeates.

In contrast, hydroxide ions (hydroxide ions: OH ^- ) and negatively charged particles (●(Ptcl ^- )) 50 are anions, and therefore are blocked by the negative cathode first electrode 14A and cannot pass through the cathode first electrode 14A. Figure 9 illustrates the behavior of the negatively charged particles 50 bouncing back within the supply chamber 12. Therefore, the negatively charged particles 50 are concentrated within the supply chamber 12. As a result, the discharge liquid 51B discharged from the supply chamber 12 has a reduced concentration of cations (Na ⁺ ) and is in a state in which the negatively charged particles 50 are concentrated.

As a result, a cationic liquid (alkaline liquid as filtrate) 16 in which the cation Na ⁺ has been transferred is obtained in the cationic chamber 17, and an exhaust liquid 51B in which negatively charged particles 50 are concentrated can be obtained from the supply chamber 12 side.

As a result, according to this embodiment, when the particle (●(Ptcl ⁻ )) 50 is a valuable material, it is possible to easily remove cations (e.g., Na ^{+ ,} etc.) that are impurities contained in the valuable material.

Here, conventionally, to remove cations (e.g., sodium ions) present in an aqueous solution containing valuable materials, it was necessary to use so-called diafiltration, which involves repeated dilution and separation procedures using large amounts of water, requiring time and effort.

<Test Example 1>
FIG. 10A is a schematic diagram of Test Example 1 of the ion separation device of the eighth embodiment.
10A , a test example will be described in which a particle-containing supply liquid 51 containing cations (Na ⁺ ), anions (OH ⁻ ), and negatively charged particles 50 was supplied into the supply chamber 12 to separate the cations, anions, and particles 50. Colloidal silica (particle size: 100 nm) was used as the particles 50.

10A, the ion separation device 10I of embodiment 1 is the ion separation device 10H shown in FIG. 9, further comprising a receiving tank 59 for receiving the supply and discharge liquid 51B from the supply chamber 12, and an alkaline line _L2 for discharging the liquid is connected to the receiving tank 59. The discharge liquid 51B (including particles (●(Ptcl ⁻ )) 50) discharged from the supply chamber 12 in which Na ⁺ has been separated and the Na ⁺ concentration has decreased is stored in the receiving tank 59.

When the pH of particle-containing supply liquid 51 is set to 7.0, particles 50 are negatively charged and are therefore blocked by negative cathode first electrode 14A, preventing them from passing through cathode first electrode 14A. Therefore, in Fig. 10A, particles 50 are concentrated in supply chamber 12. As a result, discharge liquid 51B discharged from supply chamber 12 has a reduced cation (Na ⁺ ) content and is in a state in which particles 50 are concentrated.
The results of this test are shown in Table 1.

As shown in Table 1, when the supply time of the supply liquid was 0 minutes, TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 1.006 wt %, pH was 7.0, and Na ion concentration was 21 ppm.
The properties of the discharged liquid 51B were measured. After a 40-minute supply time, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 2.277 wt %, the colloidal silica concentration was 2.3 times, the pH was 4.3, the Na ion concentration was 12 ppm, and the Na ion separation efficiency was 42.9%. After a 60-minute supply time, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 2.405 wt %, the colloidal silica concentration was 2.4 times, the pH was 3.9, the Na ion concentration was 12 ppm, and the Na ion separation efficiency was 42.9%. After a 180-minute supply time, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 2.274 wt %, the colloidal silica concentration was 2.3 times, the pH was 3.6, the Na ion concentration was 10 ppm, and the Na ion separation efficiency was 52.4%.

Furthermore, when the properties of the cationic liquid 16 were measured, after a supply time of 40 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.016 wt%, the colloidal silica concentration was 98.4 times, the pH was 9.1, the Na ion concentration was 29 ppm, and the Na ion concentration was 1.4%. After a supply time of 60 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.017 wt%, the colloidal silica concentration was 98.3 times, the pH was 9.2, the Na ion concentration was 31 ppm, and the Na ion concentration was 1.5%. After a supply time of 180 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.027 wt%, the colloidal silica concentration was 97.4 times, the pH was 9.1, the Na ion concentration was 30 ppm, and the Na ion concentration was 1.4%.

As is clear from the results in Table 1, positive ions (Na ions) were separated from the particle-containing supply liquid 51, and colloidal silica particles 50 in the discharge liquid were concentrated, demonstrating good colloidal silica separation efficiency.

<Test Example 2>
FIG. 10B is a schematic diagram of Test Example 2 of the ion separation device of Embodiment 8.
Next, an ion separator 10J shown in FIG. 10B is the same as the ion separator 10H shown in FIG. 9, except that a distilled water supply tank 55B that supplies distilled water (DW) to 55A is installed.
The test was carried out in the same manner as in Test Example 1, and colloidal silica (particle size: 100 nm) was used as the particles 50 .

The ion separation device 10J of Test Example 2 is equipped with a distilled water supply tank 55B that supplies distilled water DW to the supply tank 55A. By installing this distilled water supply tank 55B, when performing ion separation, the slurry (particles + Na ions) in the supply tank 55A is supplied with distilled water DW in an amount equal to the amount of alkaline solution 16 discharged, which is the filtrate.

By supplying this distilled water DW, the silica concentration in the supply tank 55A and the silica concentration in the discharged liquid 51B, which is the circulating liquid returning to the supply tank 55A, are kept constant (1 wt%), while sodium ions are discharged along with the filtrate, which is the alkaline liquid 16.

Here, the supply flow rate of particle-containing supply liquid 51 from supply tank 55A to supply chamber 12 was F11=10 ml/min, and the return flow rate of the circulating liquid, which is discharged liquid 51B, was F12=4 ml/min.
The supply flow rate of the distilled water DW was set to F14=6 ml/min, and the discharge flow rate of the alkaline solution 16, which was the filtrate, was set to 6 ml/min, so that they were equal in amount.
It was verified that the Na ion concentration in the circulating liquid was reduced from the initial concentration of 20 ppm in the supply tank 55A to 0 ppm as measured by an ion meter.

The results of this test are shown in Table 2.

As shown in Table 2, when the supply time of the supply liquid was 0 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) in the raw liquid supply liquid was 1.021 wt%, the pH was 9.0, and the Na ion concentration was 29 ppm.

First, the properties of the raw solution in supply tank 55A were measured. After a supply time of 40 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.818 wt%, the pH was 6.5, the Na ion concentration was 10 ppm, and the Na ion separation efficiency was 50%. After a supply time of 80 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.802 wt%, the pH was 4.0, the Na ion concentration was 5 ppm, and the Na ion separation efficiency was 75.0%. After a supply time of 120 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.764 wt%, the pH was 3.7, the Na ion concentration was 3 ppm, and the Na ion separation efficiency was 85.0%. When the supply time was 150 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.717 wt%, the pH was 3.7, the Na ion concentration was 2 ppm, and the Na ion separation efficiency was 90.0%.

Next, the properties of the discharged liquid (circulating liquid) 51B were measured. After a 40-minute supply time, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 1.845 wt%, the colloidal silica concentration was 1.9 times, the pH was 3.2, the Na ion concentration was 5 ppm, and the Na ion separation efficiency was 75%. After an 80-minute supply time, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 2.058 wt%, the colloidal silica concentration was 2.0 times, the pH was 3.2, the Na ion concentration was 3 ppm, and the Na ion separation efficiency was 85%. After a 120-minute supply time, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 1.704 wt%, the colloidal silica concentration was 1.7 times, the pH was 3.2, the Na ion concentration was 2 ppm, and the Na ion separation efficiency was 90%. When the supply time was 150 minutes, TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 1.516 wt%, the colloidal silica concentration ratio was 1.5 times, the pH was 3.2, the Na ion concentration was 0 ppm, and the Na ion separation efficiency was 100%.

Furthermore, when the properties of the cationic liquid 16 were measured, after a supply time of 40 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.013 wt %, the colloidal silica concentration was 98.7 times, the pH was 10.5, the Na ion concentration was 20 ppm, and the Na ion concentration was 1.0%. After a supply time of 80 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.009 wt %, the colloidal silica concentration was 99.1 times, the pH was 10.4, the Na ion concentration was 11 ppm, and the Na ion concentration was 0.6%. After a supply time of 120 minutes, the TS (total evaporation residue; colloidal silica concentration, sodium concentration) was 0.000 wt %, the colloidal silica concentration was 100.0 times, the pH was 9.9, the Na ion concentration was 5 ppm, and the Na ion concentration was 0.3%.
From the above results, it was found that the separation efficiency of 100% was achieved when the concentration of Na ions in the circulating liquid was 0 ppm, and the particle separation efficiency was also 100%. As a result, 100% separation efficiency of particles (●(Ptcl ⁻ ))50) was achieved, and Na ion removal (0 ppm) was also achieved.

[Embodiment 9]
11A is a schematic diagram of an ion separation device according to embodiment 9. Note that the same components as those in the first to eighth embodiments are denoted by the same reference numerals and their description will be omitted.
As shown in FIG. 11A, the ion separation device of the ninth embodiment is a seawater desalination device 70 formed by connecting the ion separation device 10A of the first embodiment and the ion separation device 10B of the second embodiment in series.

As shown in Figure 11A, the ion separation device of embodiment 9 is a modified example of the ion separation device described above, with the lower part of the figure being the ion separation device 10A of embodiment 1 and the upper part being the ion separation device 10B of embodiment 2.

The ion separation device 10A of embodiment 1 on the lower side and the ion separation device 10B of embodiment 2 on the upper side constitute a unit, and by connecting multiple such units, the efficiency of ion separation between cations and anions is significantly improved.

In this embodiment, salt water (NaCl) is used as the supply liquid 71. As shown in Fig. 11A, the lower ion separation device 10A allows cations to pass through but blocks anions, while the upper ion separation device 10B allows anions to pass through but blocks cations.
That is, the ion separation device of the fifth embodiment separates cations and anions from saltwater, and therefore can function as a so-called seawater desalination device.

As shown in FIG. 11A, the seawater desalination apparatus 70, which is an ion separation apparatus according to the ninth embodiment, has a first ion separation apparatus 10A disposed in the lower stage, and supplies a sodium chloride aqueous solution (brine) 71 into the supply chamber 12 of the first ion separation apparatus 10A.

Sodium ions in the supplied aqueous sodium chloride solution 71 permeate the cathode filter plate electrode 14 together with water. In this first ion separation device 10A, Na ions permeate the cathode filter plate electrodes 14 (14A, 14B), while chloride ions are blocked by the cathode filter plate electrodes 14, resulting in the chloride ions being concentrated and discharged from the supply chamber 12. The alkaline solution 16 through which the sodium ions have permeated is discharged from the cation chamber 17 as a first cationic liquid 16-1.
The separation efficiency of Na ions in this first stage is 95%, resulting in a reduction of Na ions by about 95%.

Next, the first cation liquid 16-1 is supplied into the supply chamber 22 of the second ion separation device 10B on the upper side. The first cation liquid 16-1, which is a cation-permeated liquid in which sodium ions have been concentrated in the first ion separation device 10A on the lower side, passes through the second ion separation device 10B, where sodium ions (Na ⁺ ) are blocked by the anode filter plate electrodes 24 (24A, 24B), allowing only water to pass through, and desalted water 72 is discharged from the anion chamber 27. The first ion separation device 10A and the second ion separation device 10B form a module as a set, and by installing multiple stages of this module, the Na ⁺ ion concentration can be reduced to the desired concentration.

To reduce the salinity of seawater from 3.5%, it is generally considered that a salt concentration of 0.05% is required for it to be used as a drink.

FIG. 11B is a schematic diagram of a seawater desalination facility including a plurality of units of the seawater desalination apparatus, which is the ion separation apparatus of the ninth embodiment.
As shown in FIG. 11B, the seawater desalination plant 70 is configured as a plurality of units, forming an n-stage module, thereby making it possible to reduce the salinity concentration to a desired level.
As a result, by configuring the seawater desalination apparatus 70 from a plurality of units, it is possible to reduce the salinity of seawater (salinity: approximately 3.5%) to that of domestic water.

In this way, the reverse osmosis membrane method, which uses reverse osmosis membranes commonly used in seawater desalination systems, reduces seawater with a salt concentration of 3.5% to a salt concentration of 0.05% so that it can be used as drinking water. However, it is possible to desalinate seawater to a sodium ion concentration similar to or higher than this.

Furthermore, even if there are particles (for example, living organisms such as plankton, organic matter, inorganic matter, etc.: (●(Ptcl ⁻ )) 50 in the seawater, as described above, the charged particles 50 can also be separated, so seawater desalination can be performed.
Particles can be separated if they are charged to one side or the other.

In addition, in conventional seawater desalination using reverse osmosis membrane equipment, particles (for example, living organisms such as plankton, organic matter, inorganic matter, etc.: (●(Ptcl ⁻ )) 50) can clog the reverse osmosis membrane, so they are treated in a stage before the reverse osmosis membrane equipment.

In other words, in conventional seawater desalination using the reverse osmosis membrane method, seawater is pretreated to be purified to the utmost extent possible, preventing clogging of the sub-nanometer pores in the reverse osmosis membrane.

In contrast, the seawater desalination plant 70 using the ion separation device of the present invention can also separate charged particles (●(Ptcl ⁻ )) 50, so even if there is a small amount of plankton, etc., separation processing is possible as long as the particles are charged.

In other words, negatively charged particles can be blocked by the lower-stage first-treatment ion separation device 10A, and positively charged particles can be blocked by the upper-stage second-treatment ion separation device 10B.

A common technique for desalinating seawater is the "reverse osmosis membrane method." This method utilizes the "reverse osmosis phenomenon," in which an artificially high pressure greater than the osmotic pressure is applied to the saltwater, forcing only the water molecules in the saltwater across a semipermeable membrane and into the freshwater.

This conventional seawater desalination method using reverse osmosis membranes poses a problem, for example, in that seawater desalination plants produce brine, which is a concentrated form of salt. In most cases, untreated brine is simply dumped into the ocean, posing a serious risk that harmful chemicals such as anti-scalant and anti-fouling agents contained in the waste could contaminate the ocean and have a negative impact on marine life and the marine ecosystem. Furthermore, because brine contains a high amount of salt, its salinity is higher than that of the receiving water, resulting in the problem of consuming dissolved oxygen (DO) in the receiving water.

The seawater desalination system 70, which utilizes the ion separation device of the present invention, does not have this brine problem. While the reverse osmosis membrane method requires a pretreatment process for the seawater supplied to the reverse osmosis membrane, the seawater desalination system of the present invention is efficient because it only requires the installation of a simple pretreatment device, a sand filter, to remove impurities from the seawater.

[Embodiment 10]
12 and 13 are schematic diagrams of an ion separation device according to a tenth embodiment.
The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof will be omitted.
The ion separator shown in FIG. 12 has an active electrode arrangement, while the ion separator shown in FIG. 13 has a passive electrode arrangement.

The ion separator 10K shown in FIG. 12 is configured such that power is supplied to all eight electrodes by connecting them to a power source.
The ion separation device 10D of this embodiment 4 has two sets of electrodes (cathode filter plate electrodes, anode filter plate electrodes) (14-1, 14-2, 24-1, 24-2), and two sets of cation chambers 17 and two sets of anion chambers 27 (17-1, 17-2, 27-1, 27-2).

The potentials of the cathode electrodes 14A-1, 14B-1, 14A-2, and 14B-2 are set to −15 V, −20 V, −30 V, and −35 V, respectively, by the power supplies (ES1, ES2, IS1, IS2, IS3, IS4, IS5, and IS6). The potentials of the anode electrodes 24A-1, 24B-1, 24A-2, and 24B-2 are set to +15 V, +20 V, +30 V, and +35 V, respectively.
The absolute values of the potentials of the cathode electrodes (14A-1, 14B-1, 14A-2, 14B-2) and anode electrodes (24A-1, 24B-1, 24A-2, 24B-2) are set to increase with increasing distance from supply chamber 12.
In contrast to this, the ion separator 10L of FIG. 13 connects power sources only to the two electrodes at both ends to supply potentials of −35V and +35V.
12 and 13, the ion separation chamber is indicated by a dashed line. A piezoelectric vibrator 80 is disposed in the ion separation devices 10K and 10L of the present embodiment.

[Embodiment 11]
FIG. 14 is a schematic diagram of an ion separation and concentration system including the ion separation device of the eleventh embodiment.

As shown in FIG. 14, the ion separation and concentration system 100 of embodiment 11 includes a valuables concentration device 102 that concentrates a dilute solution 101 containing particles 50, which are valuables, together with the particles 50, into concentrated valuables 103. The dilute solution (cations, valuables) contains at least one of cations and anions, and the particles 50. The ion separation device 104 (e.g., any of the ion separation device 10A, ion separation device 10B, ion separation device 10C, and ion separation device 10H of the above-described embodiments) removes either cations or anions, or both, from the concentrated valuables 103. Note that FIG. 14 illustrates cations as the ions.

An example of a valuable resource concentrator is a filtration device such as a rotary ceramic membrane filter (Dynafilter; registered trademark), but the present invention is not limited to this.

The ion separation and concentration system 100 of this embodiment allows a diluted solution with a low concentration of valuable materials to be concentrated once in the concentrator 102, and then impurity cations (Na ions) can be separated from the concentrated valuable materials 103.

As a result, the valuables are concentrated, the ion concentration in the valuables decreases, and the purity of the valuables improves.

In other words, as explained in the ion separation device 10H of embodiment 8 using Figure 9, by separating cations (Na ions) while circulating particles (●(Ptcl-)) 50 as is, if the particles (●(Ptcl-)) 50 are a valuable resource, it is possible to easily remove cations (e.g., Na+, etc.) that are impurities contained in the valuable resource, thereby improving product purity.

[Embodiment 11]
FIG. 17 is a schematic diagram of another ion separation device according to the eleventh embodiment.
The same components as those in the above-described embodiment are denoted by the same reference numerals and the description thereof will be omitted.

The ion separation device 10M in Figure 17 is a conventional ion separation device equipped with so-called ion exchange membrane functionality.

In this embodiment, sodium chloride (NaCl) will be used as an example.
As shown in Figure 17, the ion separation device 10M of embodiment 11 comprises an electrolyte solution supply chamber (hereinafter referred to as the ^" supply chamber") 12 that supplies an electrolyte solution (NaCl + _H2O : hereinafter referred to as the "supply liquid") 11 containing cations (Na ⁺ ) and anions ( ^Cl- ), a cathode filter plate electrode 14 arranged on both sides of the supply chamber 12 and equipped with a diaphragm (filter material) 13 that separates the cations (Na ⁺ ), a flat anode electrode (positive electrode) 15, a cation chamber 17 into which the separated cations (Na+) flow together with water as a cation liquid (hereinafter also referred to as the "alkaline liquid") 110, and a flat cathode electrode (negative electrode) 25 positioned opposite the cathode filter plate electrode 14 within the cation chamber 17.
The supply chamber 12 is provided with a supply port and a discharge port (not shown), and supplies the supply liquid 11 , which is an electrolyte, into the supply chamber 12 .

The cation chamber 17 is provided with a substitution liquid inlet and a substitution liquid outlet (not shown) for supplying a substitution liquid to replace the migrated cations, and a substitution liquid 110 is supplied into the cation chamber 17. This substitution liquid 110 replaces the cations (Na ⁺ ) that have migrated into the cation chamber 17 through ion exchange using the cathode filter plate electrode 14, to form an alkaline liquid 110A.

Here, 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 plate) 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 may be made of, for example, cellulose, but the present invention is not limited to this.

The ion separation device 10M further includes a first power supply 41 electrically connected to the flat-plate anode electrode 15 and the cathode first electrode 14A, a second power supply 42 electrically connected to the cathode first electrode 14A and the cathode second electrode 14B, and a fifth power supply 45 electrically connected to the flat-plate cathode electrode 25 and the cathode first electrode 14A.
Here, the electrode configuration is such that the cathode second electrode 14B is at a first potential (V1), the cathode first electrode 14A is at a second potential (V2), the flat anode electrode 15 is at a third potential (V3), and the flat cathode electrode 25 is at a fourth potential (V4). The power supplies (first power supply 41, second power supply 42, fifth power supply 45) are set so that the potentials satisfy the relationship V3 > V2 > V1 > V4.

The absolute value of the potential of the cathode electrode increases as it moves away from the supply chamber 12 (|V4| (40 V) > |V1| (20 V) > |V2| (10 V)).

In the ion separation device 10A shown in the first embodiment of FIG. 1, water is allowed to pass through the cathode filter plate electrode 14.
However, in the eleventh embodiment, the structure is such that only a small amount of water passes through.
This is because the supply liquid 11 and the replacement liquid 110 are supplied in a balanced manner.
As a result, at the cathode filter plate electrode 14 , the Na ions are attracted to the cathode first electrode 14 A on the cathode side and move into the cation chamber 17 .
At this time, there is almost no movement of water, so that as a result, only ions move from the supply liquid (NaCl) 11 to the replacement liquid (distilled water) 110, and the replacement liquid 110 is replaced.

Therefore, at the beginning of operation, only Na ions pass through, so the Na ion concentration in the replacement liquid (distilled water) 110 is low. However, as operation continues, only Na ions gradually pass through, so the Na ion concentration in the replacement liquid (distilled water) 110 increases, and the replacement liquid becomes alkaline.

Here, the reasons for the lack of water movement include the following:
1) The diaphragm 13 acts as a filtering resistance, and water hardly passes through.
2) There is almost no pressure difference between the two chambers (supply chamber 12/cation chamber 17).
3) The supply tank (not shown) that supplies the supply liquid 11 and the replacement liquid supply tank (not shown) are supplied from approximately the same position (i.e., the flow rate is the same as that of the pump).

As described above, according to the ion separation device 10M of this embodiment, cations (Na ions) in the supply liquid 11 supplied into the supply chamber 12 are attracted to the cathode first electrode 14A on the cathode side and move (permeate) within the cation chamber 17.

In this embodiment, these migrated (permeated) cations (Na ions) are replaced with a replacement fluid 110 supplied separately into the cation chamber 17, thereby providing the so-called ion dialysis function.

On the other hand, anions (Cl ions) are repelled by cathode first electrode 14A and cannot move, and remain in supply chamber 12.
As a result, as operation continues, the amount of cations (Na ions) in supply chamber 12 decreases, and the amount of anions (Cl ions) increases.
As the operation time progresses, the substitution liquid 110 changes from distilled water (pH 7.0) to an alkaline solution of sodium hydroxide (pH=11.8).

The replacement liquid 110 may or may not be circulated.
The feed liquid side may or may not be circulated.

That is, by implementing the following three patterns as required, it is possible to provide an ion separation device that exhibits an ion dialysis function.
Pattern 1) Neither the supply liquid nor the replacement liquid is circulated.
Pattern 2) Only one of the supply liquid and the replacement liquid is circulated.
Pattern 3) Both the supply liquid and the replacement liquid are circulated.

[Embodiment 12]
FIG. 18 is a schematic diagram of an ion separation device according to a twelfth embodiment.
The same components as those in the ion separation device of embodiment 11 are denoted by the same reference numerals and will not be described again. In this embodiment, sodium chloride (NaCl) will also be used as an example.
As shown in FIG. 18, an ion separation device 10N of this embodiment is a device that separates anions dissociated in a solvent (polar solvent; for example, water).

As shown in Figure 18, the ion separation device 10N comprises a supply chamber 12 that supplies a supply liquid 11 containing cations (Na ⁺ ) and anions (Cl ^- ), an anode filter plate electrode 24 arranged on both sides of the supply chamber 12 and equipped with a diaphragm 23 that separates the anions (Cl ^- ), a flat cathode electrode 25, an anion chamber 27 into which the separated anions (Cl ^- ) flow together with water as an anion liquid (hereinafter also referred to as "acidic liquid") 26, and further a flat anode electrode (positive electrode) 15 positioned opposite the anode filter plate electrode 24 within the anion chamber 27.
The supply chamber 22 is provided with a supply port and a discharge port (not shown), and supplies the supply liquid 11 , which is an electrolyte, into the supply chamber 22 .
The anion chamber 27 is provided with a substitution liquid supply port and a substitution liquid discharge port for supplying a substitution liquid 110 for replacing the migrated anions, and the substitution liquid 110 is supplied into the anion chamber 27 .
This substitution liquid 110 substitutes the anions (Cl ⁻ ) that have been moved into the anion chamber 27 by ion exchange using the anode filter plate electrode 24, to form an acidic liquid 110B.

The anode filter plate electrode 24 is composed of a first anode electrode 24A and a second anode electrode 24B, and a porous insulating diaphragm 23 is sandwiched between the first anode electrode 24A and the second anode electrode 24B. The diaphragm 23 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.

The ion separation device 10N has a third power supply 43 electrically connected to the flat-plate cathode electrode 25 and the anode first electrode 24A, a fourth power supply 44 electrically connected to the anode first electrode 24A and the anode second electrode 24B, and a sixth power supply 46 electrically connected to the flat-plate anode electrode 15 and the anode second electrode 24B.

Here, the electrode configuration is such that the anode second electrode 24B is at a first potential (V11), the anode first electrode 24A is at a second potential (V12), the flat cathode electrode 25 is at a fifth potential (V5), and the flat anode electrode 15 is at a sixth potential (V6). The power supplies (third power supply 43, fourth power supply 44, sixth power supply 46) are set so that the potentials are V5 < V12 < V11 < V6.

The absolute value of the anode electrode potential increases as the distance from the supply chamber 12 increases (|V6| (40 V) > |V11| (20 V) > |V12| (10 V)).

An example in which a sodium chloride solution (NaCl+H ₂ O) is supplied as the supply liquid 11 into the supply chamber 22 will be described.
As described above, the ions in supply chamber 22 are dissociated into cations (sodium ions: Na ⁺ ) and anions (chlorine ions: Cl ⁻ ). The anions, chlorine ions (Cl ⁻ ), are attracted to anode first electrode 24A disposed in supply chamber 12.

In the ion separation device 10B of the second embodiment shown in FIG. 2, water is allowed to pass through the anode filter plate electrode 24.
However, the ion separation device 10N of the twelfth embodiment is configured to allow only a small amount of water to pass through, because the supply liquid 11 and the replacement liquid 110 are supplied in a balanced manner.
As a result, anions (chlorine ions: Cl ⁻ ) are attracted to the anode first electrode 24 A on the anode side and move (permeate) into the anion chamber 27 .
At this time, there is almost no movement of water, so as a result, only chloride ions (Cl ^- ) move (permeate) from the supply liquid (NaCl) 11 in the supply chamber 22 to the replacement liquid (distilled water) 110 in the anion chamber 27, and are replaced by the replacement liquid 110, resulting in an acidic liquid.

As described above, according to the ion separation device 10N of this embodiment, anions (chlorine ions) in the supply liquid 11 are attracted to the first anode electrode 24A on the anode side and move (permeate) into the anion chamber 27.
The anions (chlorine ions) that have migrated (permeated) are replaced by a replacement liquid 110 that is separately supplied into the anion chamber 27, thereby achieving the so-called ion dialysis function.

On the other hand, cations (Na ions) are repelled by anode first electrode 24A and cannot move, and remain in supply chamber 12.
As a result, as operation continues, the amount of cations (Na ions) in supply chamber 12 increases and the amount of anions (Cl ions) decreases.
As the operation time progresses, the substitution liquid 110 changes from distilled water (pH 7.0) to an acidic liquid (pH = 2.4).

[Embodiment 13]
19 is a schematic diagram of an ion separation device according to embodiment 13. Note that the same components as those in embodiments 11 and 12 are denoted by the same reference numerals and the description thereof will be omitted.
As shown in FIG. 19, the ion separation device 10P of this embodiment is a combination of the ion separation device 10M of embodiment 11 and the ion separation device 10N of embodiment 12, and separates cations and anions and replaces them with replacement liquid 110 to obtain an alkaline liquid 16 and an acidic liquid 26.

As shown in Figure 19, the ion separation device 10P of embodiment 13 comprises a supply chamber 12 that supplies a supply liquid 11 of an electrolyte solution (e.g., NaCl solution) containing cations and anions, a cathode filter plate electrode 14 arranged on both sides of the supply chamber 12 and equipped with a diaphragm (filter paper) 13 that separates cations (Na ⁺ ), an anode filter plate electrode 24 equipped with a diaphragm 23 that separates anions (Cl ^- ), a cation chamber 17 into which the separated cations (Na + ) flow together with water as a cation liquid (alkaline liquid) 16, and an anion chamber 27 into which the separated anions (Cl ^- ) flow together with water as an anion liquid (acidic liquid) 26.
Furthermore, it is provided with a flat cathode electrode (negative electrode) 25 provided in a position opposite the cathode filter plate electrode 14 in the cation chamber 17, and a flat anode electrode (positive electrode) 15 provided in a position opposite the anode filter plate electrode 24 in the anion chamber 27.

The ion separation device 10P has a first power supply 41 electrically connected to the cathode first electrode 14A and the anode first electrode 24A, a second power supply 42 electrically connected to the cathode first electrode 14A and the cathode second electrode 14B, a fourth power supply 44 electrically connected to the anode first electrode 24A and the anode second electrode 24B, a fifth power supply 45 electrically connected to the flat-plate cathode electrode 25 and the cathode second electrode 14B, and a sixth power supply 46 electrically connected to the flat-plate anode electrode 15 and the anode second electrode 24B.

The cation chamber 17 is provided with a substitution liquid inlet and a substitution liquid outlet for supplying a substitution liquid to replace the migrated cations, and a substitution liquid 110 is supplied into the cation chamber 17. This substitution liquid 110 replaces the cations (Na ⁺ ) that have migrated into the cation chamber 17 through ion exchange using the cathode filter plate electrode 14, and the substitution liquid 110 is replaced with the substitution liquid 110 to form an alkaline liquid 110A.

The anion chamber 27 is provided with a substitution liquid supply port and a substitution liquid discharge port for supplying a substitution liquid 110 for replacing the migrated anions, and the substitution liquid 110 is supplied into the anion chamber 27 .
This substitution liquid 110 substitutes the anions (Cl ⁻ ) that have been moved into the anion chamber 27 by ion exchange using the anode filter plate electrode 24, and the substitution liquid 110 is replaced with the substitution liquid 110 to form an acidic liquid 110B.

In this embodiment, the diaphragm 13 in the cathode filter plate electrode 14 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.

Next, using Figure 19, we will explain an example of dialysis separation of cations and anions by supplying sodium chloride solution as the supply liquid 11 into the supply chamber 12.

As described above, the ions in supply chamber 12 are dissociated into cations (sodium ions: Na ⁺ ) and anions (chlorine ions: Cl ⁻ ).
Sodium ions (Na ⁺ ), which are cations, are attracted to negative cathode first electrode 14 A disposed in supply chamber 12 .

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.

As a result, at the cathode filter plate electrode 14 , the Na ions are attracted to the cathode first electrode 14 A on the cathode side and move into the cation chamber 17 .
At this time, there is almost no movement of water, so that as a result, only ions move from the supply liquid (NaCl) 11 to the replacement liquid (distilled water) 110, and are replaced by the replacement liquid 110, forming an alkaline liquid 110A.

Furthermore, chloride ions (Cl ⁻ ), which are anions, are attracted to the anode filter plate electrodes (anode first electrode 24 A, anode second electrode 24 B) 24 disposed in the supply chamber 12 opposite the cathode filter plate electrode 14 .
When an anion, chlorine ion (Cl ⁻ ), is attracted, the chlorine ion passes through.
As a result, the permeated chlorine ions replace the replacement water 110 to form an acidic solution 110B.

In contrast, sodium ions (Na ⁺ ) in supply chamber 12 are positive ions and are therefore blocked by anode first electrode 24A and cannot pass through anode first electrode 24A.

As a result, sodium ions (Na ⁺ ) are concentrated by dialysis in the cation chamber 17. Furthermore, chloride ions (Cl ⁻ ) are concentrated by dialysis in the anion chamber 27. As a result, the third supply/discharge liquid 11C discharged from the supply chamber 12 has a reduced concentration of sodium ions (Na ⁺ ) and chloride ions (Cl ⁻ ).

As described above, according to the ion separation device 10P of this embodiment, in the ionic state of the supply liquid 11 supplied into the supply chamber 12 (a mixture of sodium ions (Na ⁺ ) and chloride ions (Cl ^- ): pH = 7.0), sodium ions (Na ⁺ ) pass through the cathode filter plate electrode 14 located on the left side of the supply chamber 12, and sodium ions (Na ⁺ ) are concentrated in the cation chamber 17.
At the same time, chloride ions (Cl ^{− )} pass through the anode filter plate electrode 24 disposed on the right side of the supply chamber 12 , and are concentrated in the anion chamber 27 .

The separation of cations and anions in this ion separator 10P was confirmed using pH and a BTB reagent. Here, a 0.05% aqueous solution of sodium chloride (NaCl) was used as the feed liquid 11, and the pH of the feed liquid was adjusted with a carbonate buffer to pH 7.0.
At the same time, the pH state in each chamber was visualized by coloring using BTB (bromothymol blue; BTB) reagent.

As a result of this confirmation, it was found that the ionic state of the supply liquid 11 supplied to the supply chamber 12 (a mixture of sodium ions (Na ⁺ ) and chlorine ions (Cl ^- ): pH = 7.0) was separated into ions, and as a result, the pH of the alkaline liquid 110B discharged from the cation chamber 17 became 11.8, and the pH of the acidic liquid 110B6 discharged from the anion chamber 27 became 2.4.

Furthermore, as a result of testing with the BTB reagent, the feed solution (pH = 7.0) 11 supplied to the feed chamber 12 was green in color, 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 changed to orange due to Na ions, and the acidic solution 26 changed to green due to copper chloride (CuCl ₂ ), confirming that ion separation was achieved reliably in each flame color reaction test.

As a result, the circulating liquid, which is the third supply/discharge liquid 11C discharged from the supply chamber 12, has a reduced sodium ion (Na ⁺ ) content and a reduced chloride ion (Cl ⁻ ) content (pH=4.5).

Furthermore, similar to the ion separation device 10-2 shown in Figure 3B, a piezoelectric vibrator (vibration member) 80, which is a piezoelectric member, may be installed in the supply chamber 12, cation chamber 17, and anion chamber 27. This prevents adhesion of particles 42, allowing the overall voltage applied to the anode first electrode 24A and anode second electrode 24B to be lowered.

[Embodiment 14]
20 is a schematic diagram of an ion separation device according to embodiment 14. Note that the same components as those in the above-described embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

Although the ion separation devices 10M to 10P of the eleventh to thirteenth embodiments have been described as techniques for separating cations or anions in an electrolyte solution by dialysis, the ion separation device of the present invention is not limited to this.
The ion separation device 10Q of embodiment 14 has the same configuration as the ion separation device 10P of embodiment 19 (see Figure 19) described above, but it also continuously performs dialysis separation of ions in a particle-containing supply liquid 51 in which particles (Ptcl ^- in the figure, ``●'') 50 are mixed in the supply liquid supplied to the supply chamber 12.
That is, in the electrodialysis apparatus of the prior art, when particles are mixed in the material to be separated, the particles adhere to the dialysis membrane, preventing the electrodialysis from proceeding.

In contrast, the ion separation device 10 of this embodiment can continue to perform dialysis separation even when particles are mixed in.
Like anions (chlorine ions), particles (negatively charged) 50 repel cathode first electrode 14A and do not move to cation chamber 17. On the other hand, there is no movement of water in anion chamber 27, so the particles that would otherwise move with the movement of water hardly move at all.
This is because there is no pressure difference between the supply chamber 12 and the anion chamber 27 for the supply liquid 11 and the replacement liquid 110, so there is almost no movement of water.
As a result, the particles 50 remain in the supply chamber 12, but only both ions (cations and anions) permeate into both chambers (cation chamber 17 and anion chamber 27), where they are replaced with the replacement liquid, becoming alkaline liquid 110A and acidic liquid 110B, respectively.

[Embodiment 15]
FIG. 21 is a schematic diagram of an ion separation device according to a fifteenth embodiment.
As shown in FIG. 21 , the ion separation device 10R of the fifteenth embodiment includes the ion separation device 10P of the thirteenth embodiment (see FIG. 19 ), a supply tank 55 that supplies an electrolyte solution (supply liquid 11) containing cations, a supply line _L1-1 that supplies the supply liquid 11 from the supply tank 55 to the supply chamber 12 via a supply pump P-1, a circulation line L1-2 that circulates the first supply/discharge liquid 11C from the supply chamber 12 to the supply chamber 12, an alkali line L3-1 that discharges alkaline solution 110A from the cation chamber 17 to the alkali tank 56, an alkali line _L3-2 that circulates the alkaline solution 110A from the alkaline tank 56 to the cation chamber 17 as replacement water by the pump P-2, an acid line L5-1 that discharges acid solution 110B from the anion chamber 27 to the acid solution tank 58, and an acid line _L5-2 that circulates the acid solution 110B from the acid solution tank 58 to the anion chamber 27 as replacement water by the pump P-3. _5-2 and is equipped with.

By using the ion separation device 10R of this embodiment 15, alkaline liquid 110A, which is a cation liquid that has been replaced with the replacement liquid 110, can be continuously obtained in the alkaline tank 56, and acidic liquid 110B, which is an anion liquid that has been replaced with the replacement liquid 110, can be continuously obtained in the acidic liquid tank 58.

[Embodiment 16]
FIG. 22 is a schematic diagram of an ion separation and concentration system including the ion separation device of the eleventh embodiment.

As shown in FIG. 22, the ion separation and concentration system 200 of embodiment 16 includes a valuables concentration device 102 that concentrates a dilute solution 101 containing particles 50, which are valuables, together with the particles 50, into concentrated valuables 103. The dilute solution (cations, valuables) contains at least one of cations and anions, and the particles 50, and an ion separation device 204 (e.g., ion separation device 10M, ion separation device 10N, ion separation device 10C, or ion separation device 10P) that removes either or both of the cations and anions from the concentrated valuables 103.

Examples of valuable resource concentrators include filtration devices such as rotary ceramic membrane filters (Dynafilter; registered trademark), but the present invention is not limited to these.

The ion separation and concentration system 200 of this embodiment allows a diluted solution with a low concentration of valuable materials to be concentrated once in the concentrator 102, and then the impurities, cations and anions, can be separated from the concentrated valuable materials 103.

As a result, the valuables are concentrated, the ion concentration in the valuables decreases, and the purity of the valuables improves.

That is, as explained in the ion separation device 10Q of embodiment 14 using Figure 20, by separating cations (Na ions) while circulating the particles (●(Ptcl ^- )) 50 as they are, if the particles (●(Ptcl ^- )) 50 are a valuable material, it becomes possible to easily remove cations (e.g., Na ions, etc.) that are impurities contained in the valuable material, thereby improving the purity of the product.

Furthermore, even if the diluted solution contains only anions or a mixture of cations and anions rather than cations, the ions can be easily removed, thereby improving product purity.

In addition, the electrode configuration of the ion separation device with the above-mentioned ion dialysis separation function may also be configured with the active electrode arrangement shown in Figure 12 or the passive electrode arrangement shown in Figure 13.

[Embodiment 17]
FIG. 23 is a schematic diagram of a seawater desalination system including the seawater desalination apparatus 70 of the ninth embodiment described above.
23 , a seawater desalination system 1000 according to the seventeenth embodiment of the present invention includes a first pretreatment device 1001, a second pretreatment device 1002 provided downstream of the first pretreatment device 1001, and a seawater desalination device 70 provided downstream of the second pretreatment device 1002. The devices are connected by pipes.

The first pretreatment device 1001 is, for example, a sand filter device, equipped with a pretreatment container into which seawater 1010A taken from the sea is introduced and a filter material made of filter sand or the like filled into the pretreatment container. The seawater 1010A supplied to the first pretreatment container 1001 passes through the filter material, and contaminants such as turbid components and impurities contained in the seawater 1010A are removed.

The second pretreatment device 1002 includes an adsorption vessel (e.g., a column, etc.) (not shown) to which seawater 1010A from the first pretreatment device 1001 is supplied, and a hydrophilic polymer adsorbent, for example, placed within the adsorption vessel. The hydrophilic polymer adsorbent is a material that can efficiently adsorb biopolymers, which are the main cause of biofouling among fouling-causing substances.

23 , a seawater desalination system 1000 takes in seawater 1010 from the ocean and supplies the seawater 1010 through piping to a first pretreatment device 1001. The seawater 1010 supplied to the first pretreatment device 1001 is pretreated by the first pretreatment device 1001, and impurities contained in the seawater 1010 are removed.
Pretreated seawater 1010A pretreated in the first pretreatment device 1001 is supplied as first treated water to the second pretreatment device 1002. The second pretreatment device 1002 adsorbs and removes fouling-causing substances contained in the first treated water.
The second treated seawater 1010B from which fouling-causing substances have been adsorbed and removed in the second pretreatment device 1002 is supplied to the seawater desalination device 70, where it is separated into concentrated water 1011 and fresh water 1012.

As mentioned above, in the reverse osmosis membrane method that uses a reverse osmosis membrane, which is generally used in seawater desalination systems, seawater with a salinity of 3.5% is reduced to a salinity of 0.05% so that it can be used as drinking water. However, it is possible to desalinate seawater to a sodium ion concentration at the same level or higher. Furthermore, seawater can be desalinated even when it contains particles (for example, living organisms such as plankton, organic matter, inorganic particles, etc.). In other words, particles contained in seawater can be separated if they are charged to one of the two.
Therefore, depending on the particles to be removed, it may be possible to omit the installation of the second pre-treatment device 1002. This allows the system configuration to be simplified.

The present invention can be used in seawater desalination systems and seawater desalination methods in general.

10A to 10R Ion separation device 11 Electrolyte solution (supply liquid)
11A First supply and discharge liquid 11B Second supply and discharge liquid 11C Third supply and discharge liquid 12 Supply chamber 12a Inlet 12b Supply liquid introduction line 12c Third discharge port 13 Diaphragm (filter material)
14 Cathode filter plate electrode 14A Cathode first electrode 14B Cathode second electrode 15 Flat plate anode electrode 16 Cationic liquid (alkaline liquid)
17 Cation chamber 17a First outlet 22 Supply chamber 24 Anode filter plate electrode 24A First anode electrode 24B Second anode electrode 25 Flat plate cathode electrode 26 Anion liquid (acid liquid)
27 Anion chamber 27a Second discharge port 50 Particles 51 Particle mixed supply liquid 51A Drain liquid 70 Seawater desalination equipment 71 Sodium chloride aqueous solution (seawater)
80 Piezoelectric vibrator 100 Ion separation and concentration system 110 Replacement liquid 110A Alkaline liquid 110B Acidic liquid 1000 Seawater desalination system DW Distilled water P Supply pump

Claims (4)

a first ion separation device that allows cations in seawater to pass through and blocks anions;
a second ion separation device provided downstream of the first ion separation device, which allows anions in the permeate through which cations have permeated to pass and blocks cations;
The seawater desalination plant is provided with a unit including the above.
The seawater desalination apparatus comprises:
a supply chamber for supplying seawater containing cations and anions;
a cathode filter plate electrode disposed on both sides of the supply chamber and equipped with a diaphragm having pores for separating cations;
a flat anode filter plate electrode provided with a diaphragm having pores for separating anions;
a cation chamber into which the separated cations flow together with water as a cation liquid;
The cathode filter plate electrode is
a cathode first electrode on the supply chamber side;
a cathode second electrode disposed on the cation chamber side across the diaphragm;
a first power source electrically connected to the anode electrode and the cathode first electrode of the flat plate;
a second power source electrically connected to the cathode first electrode and the cathode second electrode;
The anode filter plate electrode is
an anode first electrode on the supply chamber side;
a second anode electrode disposed on the anion chamber side across the diaphragm;
a third power source electrically connected to the cathode electrode and the anode first electrode of the flat plate;
a fourth power source electrically connected to the anode first electrode and the anode second electrode . As a pretreatment device for the seawater desalination device,
a first pretreatment device provided with a filter for removing impurities from seawater;
a second pretreatment device provided with a hydrophilic polymer adsorbent for adsorbing biopolymers in the seawater from the first pretreatment device;
2. The seawater desalination system according to claim 1 , further comprising: a first ion separation device that allows cations in seawater to pass through and blocks anions;
a second ion separation device provided downstream of the first ion separation device, which allows anions in the permeate through which cations have permeated to pass and blocks cations;
The seawater desalination system of claim 1 is provided with a seawater desalination apparatus comprising the above as a single unit,
A seawater desalination method comprising reducing the salt concentration in the seawater. As a pretreatment device for the seawater desalination device,
a first pretreatment device provided with a filter for removing impurities from seawater;
a second pretreatment device provided with a hydrophilic polymer adsorbent for adsorbing biopolymers in the seawater from the first pretreatment device;
4. The method for desalination of seawater according to claim 3 , further comprising: