KR20180122130A - The electricity-generating device salinity gradient - Google Patents

Abstract

The present invention provides a device and a method for electrochemically concentrating and regenerating effluent water produced by using carbon dioxide in combustion flue gas for electricity production by applying a salinity gradient power generation device connection technology. A salinity gradient power generation device comprises: an ion generation part including a cation exchange membrane and an anion exchange membrane, introducing a first solution including an absorbent, discharging a second solution including an absorbent ion, and arranged to produce electricity as a carbonate and a hydrogen ion included in the first solution pass through the cation exchange membrane and the anion exchange membrane; and a concentration part separating the absorbent ion and water in the second solution.

Description

The electricity-generating device salinity gradient < RTI ID = 0.0 >

The present invention relates to a concentration difference generation apparatus using a carbon dioxide absorbent, and more particularly, to a concentration difference generation apparatus and method for reducing the energy required for regenerating absorbent by concentrating discharged water produced after carbon dioxide captured in an absorbent is used for electricity production.

Carbon dioxide accounts for the largest amount of greenhouse gases that cause global warming. In particular, large amounts of coal, oil, natural gas, and other thermal power plants are produced in large quantities in major production industries such as steel and cement.

According to the IEA data released in 2016, global warming caused by a large amount of carbon dioxide emissions is a big problem in terms of energy security. Carbon capture and sequestration (CCS) , Which is one of the most advanced technologies that can reduce global warming at the present technology stage. It consists of three stages: capture, compression, transportation and storage.

CCS technology is consuming a lot of cost in the collection part, and a lot of technology development is required. The capture of carbon dioxide can be separated and collected from the exhaust gas by a physicochemical method such as an absorption method, an adsorption method, and a membrane separation method.

Among these, the continuous absorption / regeneration process using a liquid amine sorbent is known as the most matured carbon dioxide capture and storage process applicable to the post-combustion carbon dioxide capture, but even in this technology, the consumed price for absorbent regeneration is more than half There is a problem that it is required.

The most commonly used amine-based liquid sorbents in the latter stage of combustion capture are classified into primary, secondary and tertiary amines depending on their chemical composition.

[Table 1]

Of these, primary and secondary amines are classified as unhindered amines. Carbamates resulting from the carbon dioxide absorption reaction can absorb 0.5 mole of carbon dioxide per mole of amine, but they are produced in a very stable form, There is a drawback that a large amount of energy is consumed to break the bond and regenerate the absorbent.

On the other hand, tertiary amines form unstable ancibamates in the carbon dioxide absorption process and, instead, form carbonates (HCO ₃ ^- ). This reaction is advantageous in that it can absorb 1 mole of carbon dioxide per mole of amine and that the regenerated energy of the absorbent is reduced. However, since the carbon dioxide capture rate is slow, it is difficult to remove CO ₂ .

If the problem of the absorption rate of the tertiary amine is improved, it can be expected that the energy efficiency of the whole process can be increased.

In particular, Oxynekan and Rochelle et al. Have reported the use of MDEA and piperazine (PZ) in combination to increase the rate of carbon dioxide uptake and reduce total energy by 15 to 22%.

According to recent research trends, use of a mixture of primary and tertiary amines (eg, MEA and MDEA) or use of a mixture of secondary and tertiary amines (eg, DEA and MDEA) Research is increasing. The use of such a mixed solution combines a high reaction rate, which is an advantage of primary and secondary amines, and a high absorption capacity, which is an advantage of tertiary amines, and studies are being conducted to apply it to many industrial fields. In addition, studies on synthetic tertiary amines have been carried out variously, and 4- (dimethylamino) -2-butanol (DMAB), 4- (dipropylamino) -2-butanol (DBAB), 4 - ((2-hydroxyethyl) (methyl) amino) -2-butanol (HEMAB), 4- (2-hydroxyethyl) ) -2-butanol (DEAB), etc. (Singto et al., 2016).

Carbon dioxide capture cases using ionic liquids (eg, amino-alkymidazolium ionic liquids, tetraalkylphosphonium amino acid ionic liquids, tetraalkylammonium amino acid ionic liquids, etc.) have also been studied and include amino acid ionic liquids [ NCE11] [Gly], [N1111] [Lys], and [N2222] [Lys]) and MDEA were also used to collect carbon dioxide.

The regeneration process of the carbon dioxide absorbent is mainly a thermal desorption process, and the absorbed carbon dioxide is desorbed from the absorbent by applying heat of about 70 degrees for the tertiary amine and about 120 degrees for the primary and secondary amine. The energy consumed at this time is about 0.9 GJ / tonCO ₂ based on MDEA.

In recent years, studies for recovering carbon dioxide from an absorbent using an electrochemical method, a membrane separation method, and the like have been carried out. Recently, according to lizuka et al. (2012) (EDA), Aminoetthylethanolamine (AEEA), Diethylenetriamine (DETA), and the like can be used as the absorbent in the electrochemical desorption system shown in FIG. 2 according to Stern et al. (2013) , And triethyleneetetramine (TETA).

These CO2 adsorption and desorption methods can reduce the energy consumption compared to the conventional thermal desorption process, but the minimum energy consumption for the operation of the system is essential. If the input of sustainable energy sources such as renewable energy is not carried out simultaneously, The Net Carbon Emission will continue to have a positive value. In other words, a strategy to make the carbon footprint zero (Carbon Negative Map) and active efforts for it should be pursued.

KR registration 1541994 (2015.07.29)

1. Atsushi Iizuka et al., Separation and Purification Technology 101 p 49-59 (2012) 2. Stern et al., Energy & Environmental Science 6, p 2505-2517 (2013)

In order to solve the problem of injecting very high thermal energy when regenerating a carbon dioxide absorbent, the present invention uses electrochemical methods to concentrate the effluent water produced by using carbon dioxide in the combustion flue gas for electricity generation by applying a salt- And an apparatus and method for reproducing data.

In order to achieve the above object, a first solution containing a cation exchange membrane and an anion exchange membrane is introduced, and a second solution containing an absorbent ion is discharged. In the movement of the first solution, An ion generator configured to generate electricity as the carbonate and hydrogen ions contained in the ion exchange membrane pass through the cation exchange membrane and the anion exchange membrane; And a concentrating unit for separating the absorbent ions and water from the second solution; And the concentration-difference power generation device.

The enrichment unit includes an ion concentration polarization module and is provided to separate the second solution into water and absorbent ions in different channels, respectively.

The ion concentration polarization module may further include an inlet channel through which the second solution flows, a first channel through which the absorbent ions are branched and a second channel through which water is discharged, a first channel and a second channel branching region, And includes an electrode and a ground unit for applying a periodic field to the nano junction including the ion selective layer, and when the electric field is applied to the nano junction, the ion concentration polarization phenomenon is induced in the branch region do.

The electric field applied to the nano junction includes using electricity generated by the ion generator.

In addition, the enrichment unit includes a separator for separating the second solution into water and absorbent ions using a reverse osmosis membrane.

Further, the apparatus further comprises an absorbent regeneration section for regenerating the absorbent from the second solution passed through the thickening section.

In addition, the absorbent regeneration section includes regeneration of the absorbent by heating.

Further, the absorbent regeneration section includes separating cations contained in the absorbent by ion concentration polarization phenomenon to regenerate the absorbent.

And supplying the second solution passed through the concentrated portion to the ion generating portion.

Further, the apparatus further includes a mineralization unit including a container into which the second solution having passed through the enrichment unit flows, and a stirring part for stirring the mixture in the container.

In addition, the thickness of the ion selective layer may be 10 to 30 占 퐉.

In addition, the ion selective layer includes a porous support or a pore filling structure.

In addition, the ion selective layer includes those that are homogeneous or heterogeneous.

In addition to this, the present invention provides a method of manufacturing a semiconductor device, comprising: generating electricity by introducing a first solution into the above-described ion generator; Separating the absorbent ions and the water through the concentrated solution by passing the second solution through the ion generator; The method comprising the steps of:

The enrichment unit also includes separating the second solution through the ion concentration polarization module into absorbent ions and water.

In addition, the enrichment unit includes separating the second solution into absorbent ions and water using a reverse osmosis membrane.

And supplying the second solution passed through the concentrated portion to the ion generating portion.

According to the present invention, energy can be produced through the concentration-difference power generation apparatus, and the energy produced at this time can be effectively used for the regeneration of the absorbent at the downstream end and the carbon dioxide recovery process, thereby realizing a carbon negative system. It is possible to reduce carbon dioxide in the air at the present time, and at the same time to recover the carbon dioxide and to make the resources.

In addition, when a micro-level dispersion type or mobile type ion generation device is manufactured, it is possible to install any place where carbon dioxide is generated, such as a small-sized diesel generator, an automobile, , And can effectively control the energy production and emissions of carbon dioxide.

1 is a schematic diagram showing a conventional biplot electrodialysis apparatus.
2 is a schematic diagram showing an electrochemical desorption apparatus of the prior art.
3 is a schematic diagram of a concentration difference generation apparatus according to an embodiment of the present invention.
4 is a schematic diagram of an ion generating section according to an embodiment of the present invention.
5 is a schematic diagram of an ion concentration polarization module of a concentrating unit according to an embodiment of the present invention.
6 to 8 are schematic diagrams of a concentration difference generation device according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

In addition, the same or corresponding reference numerals are given to the same or corresponding reference numerals regardless of the reference numerals, and redundant description thereof will be omitted. For convenience of explanation, the size and shape of each constituent member shown in the drawings are exaggerated or reduced .

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

The present invention relates to a concentration difference generation apparatus using a carbon dioxide absorbent, and more particularly, to a concentration difference generation apparatus and method for reducing the energy required for regenerating absorbent by concentrating discharged water produced after carbon dioxide captured in an absorbent is used for electricity production. According to the exemplary embodiment of the present invention, a carbon negative system can be realized by producing electricity using carbon dioxide and using it for the regeneration of absorbent and the carbon dioxide recovery process.

FIG. 5 is a schematic diagram of an ion concentration polarization module, and FIG. 6 to FIG. 8 are diagrams of another exemplary concentration-difference power generation device of the present invention. FIG. It is a schematic diagram.

3, the concentration-difference power generation device 10 of the present invention includes a cation exchange membrane and an anion exchange membrane, in which a first solution containing an absorbent is introduced, a second solution containing absorbent ions is discharged, An ion generator 100 is provided to generate electricity as the carbonate and hydrogen ions contained in the first solution pass through the cation exchange membrane and the anion exchange membrane during the movement of the first solution, And a concentrating unit 200 for separating the water.

4, the ion generator 100 includes a first flow path 110 through which a first solution containing an absorbent flows, a cation exchange membrane 120 that selectively passes ions, and an anion exchange membrane 120. [ One or more second flow paths 130 and 130 'through which the fluid flows, and one or more electrodes 140 and 140' that generate electricity by the movement of ions.

For example, the electrode 140, the second flow path 130, the cation exchange membrane 120, the first flow path 110, the anion exchange membrane 121, the second flow path 130 'and the electrode 140' Lt; / RTI >

For example, after the electrode 140 ', the second flow path 130, the cation exchange membrane 120, the first flow path 120, and the second flow path 120 may be alternately arranged. A plurality of the anion exchange membrane 121, the second flow path 130 'and the electrode 140' may be arranged in this order.

On the other hand, the first solution includes an absorbent, a carbon dioxide or a carbonate, and an absorbent in which carbon dioxide is absorbed.

Particularly, the absorbent may contain, as solute, at least one of a primary amine (MEA), a secondary amine (DEA), a tertiary amine (MDEA, TEA), a carbonate absorbent (K ₂ CO ₃ ), a piperazine Or a mixture thereof, ammonia, and the like, or a plant wastewater having basicity, such as ammonia or the like, and effluent water.

Further, the absorbent may include at least one of pure water, fresh water, brackish water, brine, a mixture of alcohol and water, and factory wastewater having basicity as a solvent. Here, the factory wastewater having basicity may be, for example, ammonia wastewater or the like.

In addition, the absorbent may include, as an additive, a corrosion inhibitor, an aggregation aid, an antioxidant, an O ₂ scavenger, a defoamer, or a mixture thereof.

In addition, the fluid may contain at least one of pure water, fresh water, nordic water, brine, a mixture of alcohol and water, and a factory wastewater, in the same manner as the absorbent solvent. Here, the factory wastewater having basicity may be, for example, ammonia wastewater or the like.

For example, the first solution may be a product formed through absorption of carbon dioxide using an absorbent during a carbon capture storage (CCS) collection process.

This reaction can be represented by the following chemical reaction formula 1.

[Chemical reaction formula 1]

Abs (absorbent) (aq) + CO ₂ (g) ↔ Abs ⁺ (aq) + HCO ₃ ^- (aq)

As described above, when the carbon dioxide is encountered, the absorbent becomes selective as a cation. As the molecular weight is relatively large, it is difficult to pass the cation exchange membrane, and the absorbent is not lost due to the size exclusion effect.

Meanwhile, when the first solution containing the absorbent flows into the first flow path 110, the carbonate (HCO ₃ ^- ) contained in the first solution moves through the anion exchange membrane 121, H ⁺ ) ions migrate through the cation exchange membrane 120 to generate electricity as the potential difference is generated. Here, the hydrogen (H ⁺ ) ion may be present in water (H ₂ O) contained in the solvent of the absorbent.

More specifically, as the carbonate and hydrogen ions migrate, the water (H ₂ O) of the fluid flowing through the second flow path (130, 130 ') moves to the first flow path (110).

The concentration of the first solution flowing into the first flow path 110 should be higher than the concentration of the flowing liquid flowing through the second flow path 130 or 130 ' The movement of the ions can be shifted up to 50% of the concentration of the first solution.

As described above, the second solution may be discharged after electricity is generated in the ion generator 100. [

Here, the second solution may partially remove carbonate from the first solution, and may include a relatively large amount of water as compared with the first solution.

That is, it includes an absorbent ion and water containing a high or low concentration of residual carbonate.

Meanwhile, the present invention may include a concentrating unit 200 for separating the absorbent ions and water from the discharged second solution.

The enrichment unit 200 may separate the second solution into water and absorbent ions through the ion concentration polarization module 210.

3, the ion concentration polarization module 210 includes an inlet channel 211 through which the second solution flows, a first channel 212 through which the absorbent ions are branched, A nano junction 214 including an ion selective layer, a nano junction 214 provided in the second channel 213, the first channel 212 and the second channel 213, An electrode (not shown) and a grounding portion 215 provided for application.

Here, one or more pairs of electrodes may be provided.

In addition, the nano junction 214 may be a nano-sized channel, and may include an ion-selective layer including an ion exchange membrane or an ion exchange resin.

The thickness of the ion selective layer may be 10 to 30 mu m.

In addition, the ion selective layer may have a porous support or a pore filling structure.

In addition, the ion selective layer may be a homogeneous ion selective layer made of a single material, a compound, and a mixture, or a heterogeneous ion selective layer made of a mixture thereof.

More specifically, when an electric field is applied to the grounding part 215 through the electrode to apply an electric field to the nanocrystal 214 including the ion selective layer, a point where the nanocrystal 214 is introduced, that is, The ion concentration polarization layer can be induced in the branch regions of the ion implantation regions 212 and 213 to form the ion depletion region 220.

Here, the electric field applied to the nano junction may be 10 to 100 V / cm.

The absorbent ions in the second solution passing through the inlet channel 211 due to the force due to the ion concentration polarization are pushed out of the interface of the ion depletion region 220 and discharged to the first channel 212, It is possible to concentrate the absorbent ions.

Particularly, the second solution discharged from the concentrating part 200 through the above process can remove approximately 50% of the water contained in the second solution before the introduction of the concentrating part 200, The solution can be concentrated about twice as much as the second solution.

Here, the ion concentration polarization module 210 may be driven using electricity generated by the ion generating section 100. That is, the electric field applied to the nanocrystals 214 may be driven using electricity generated by the ion generator 100.

When a certain amount of water is separated by using the ion concentration polarization module 210, the amount of heat required for the absorbent regeneration unit in the method of regenerating the absorbent by applying heat to the downstream end can be reduced to enhance the energy efficiency.

Here, the ion concentration polarization phenomenon is one of the electrochemical phenomena observed in a structure having a nanofilm. When the thickness of the electric double layer is similar to that of the nanofilm, the electric double layer is overlapped and the single ion permeability . That is, the ions having the same charge as the nanomembrane charge can not pass through the nanomembrane due to the diffusion and drift force, and only the ions having the opposite charge to the nanomembrane charge can pass through. At this time, depression and concentration phenomenon of ions are induced at the nano-membrane boundary. Since strong electrical repulsive force acts between the ions that have not passed through the nanofiber, both cation and anion are affected, The ion concentration polarization phenomenon is induced, and ions to be separated can be separated according to the ion concentration polarization phenomenon.

Also, the thickening part 200 may be a reverse osmosis (RO) membrane.

More specifically, water (H ₂ O) is allowed to pass through the reverse osmosis membrane by applying pressure to the second solution, so that it can be separated into water and absorbent ions.

Herein, the reverse osmosis membrane can be used as long as it is used in the conventional reverse osmosis process, and can be appropriately selected and used according to the purpose and conditions of use by the ordinary experts in the art.

 6, the concentration-difference power generation apparatus 10 of the present invention may further include an absorbent regeneration section 300 for regenerating the absorbent from the second solution that has passed through the thickening section 200 have.

More specifically, the absorbent regeneration unit 300 can regenerate the absorbent by heating.

In particular, a heater for heating the absorbent regeneration unit 300 may be additionally provided, and the carbonate contained in the second solution may be regenerated as an absorbent by being desorbed from the absorbent ion by receiving a heat source from the heater.

Further, the absorbent regeneration section 300 can regenerate the absorbent by separating the cations contained in the absorbent by the ion concentration polarization phenomenon.

In particular, the ion concentration polarization module may further include an ion concentration polarization module for inducing the ion concentration polarization phenomenon. The ion concentration polarization module may include a channel through which the absorbent ions including the carbonate of the second solution discharged from the concentration unit 200 pass And the channel may further comprise an ion selective polymer.

The ion-selective polymer may be, for example, a polymer electrolyte membrane that selectively passes cations but does not pass anions.

Here, the ion concentration polarization module may be driven using electricity generated by the ion generating section 100, and an electric field may be applied to the ion concentration polarization module using electricity generated from the ion generating section 100 , Ion concentration polarization occurs in the region adjacent to the ion-selective polymer, and absorbent ions having a cation among the absorbent ions including the carbonate of the second solution discharged from the thickening portion 200 pass through the ion-selective polymer, Lt; / RTI >

Also, the ion concentration polarization module 210 of the concentrating unit 200 of the present invention can be used.

Referring to FIG. 7, the concentration-difference power generation apparatus 10 of the present invention may re-supply the second solution separated from water in the concentrating section 200 to the ion generating section 100.

More specifically, since the second solution having passed through the thickener 200 contains the residual carbonate, it is supplied again to the ion generator 100 to be used again for the power generation, and once again the thickener 200 It is possible to more efficiently regenerate the absorbent.

In addition, referring to FIG. 8, the concentration difference generation apparatus 10 of the present invention may further include a mineralization unit 400.

More specifically, the mineralizing unit 400 further includes a container 410 in which the second solution having passed through the thickening unit 200 is introduced, and a stirring unit 420 for stirring the mixture in the container. .

When the second solution flows into the container 410 containing the calcium, the carbonate contained in the second solution reacts with the calcium by the agitation of the agitator 420, so that the mineralization reaction proceeds, Can be removed.

Here, in addition to the calcium, a mineralization reaction may be caused by using a multivalent ion having hardness such as aluminum or magnesium. In addition, mineralization can be induced by using phosphate or the like.

This reaction can be represented by the following chemical reaction formula (2).

 [Chemical reaction formula 2]

Abs ^{+ _{(absorbent) (aq) + HCO 3 -}} (aq) + M + n + (n-1) e- ↔ Abs (aq) + MCO3 (s) (2)

Here, M ^{+ n} means a multivalent cation having a valence of 2 or more.

As described above, the mineralization unit 400 is additionally provided in the concentration-difference power generation apparatus 10 of the present invention, so that carbon dioxide can be recovered and recycled.

The present invention also provides a concentration difference generation method.

For example, the concentration difference generation method is related to a concentration difference generation method through the above-described concentration difference generation apparatus.

Therefore, details of the concentration difference generation method described later can be applied equally to those described in the concentration difference generation apparatus.

An exemplary method of generating a concentration difference according to the present invention includes the steps of generating electricity by introducing a first solution into an ion generator (100) of the ion generator (10) described above; Separating the absorbent ions and water through the concentrated solution (200) and passing through the ion generator (100); .

In addition, the concentration difference generation method includes an absorbent regeneration step for regenerating the absorbent from the second solution that has passed through the thickening part 200; As shown in FIG.

Further, the method may further include a re-supplying step of re-supplying the second solution having passed through the concentrating unit 200 to the ion generating unit 100.

In addition, the second solution passing through the concentrating unit 200 may be further mineralized in the mineralizing unit 400.

More specifically, the concentrating unit may be provided to separate the second solution into water and absorbent ions through the ion concentration polarization module.

In addition, the concentrating unit may be provided to separate the second solution into water and absorbent ions using a reverse osmosis membrane.

As described above, according to the present invention, it is possible to realize a carbon negative system by solving the problem of injecting very high thermal energy when regenerating the conventional carbon dioxide absorbent, and it is possible not only to regenerate the absorbent, but also to recover the carbon dioxide have.

In particular, carbonates can be mineralized and recycled as useful resources such as CaCO ₃ , MgCO ₃ , NaHCO ₃ and Na ₂ CO ₃ , and utilized as various industrial raw materials.

In addition, when the above-described apparatus is manufactured in a micro-level dispersion type or mobile type, it is possible to install any place where carbon dioxide is generated, such as a small diesel generator, a car, It is possible to effectively control the energy production and the emitted carbon dioxide.

10: Concentration difference generator
100: ion generator 110: first flow path
120: Cation exchange membrane 121: Anion exchange membrane
130, 130 ': a second flow path 140, 140'
200: enrichment unit 210: ion concentration polarization module
300: absorbent regeneration unit
400: Mineralizer

Claims (17)

A first solution containing a cation exchange membrane and an anion exchange membrane, wherein a first solution containing an absorbent is introduced, a second solution containing an absorbent ion is discharged, and in the process of transferring the first solution, a carbonate and a hydrogen ion An ion generator arranged to generate electricity as it passes through the cation exchange membrane and the anion exchange membrane; And
A concentrating unit for separating the absorbent ions and water from the second solution; And the concentration difference generator. The method according to claim 1,
Wherein the enrichment unit includes an ion concentration polarization module and is configured to separate the second solution into water and absorbent ions in different channels, respectively. 3. The method of claim 2,
The ion concentration polarization module comprises:
A first channel through which the absorbent ions are discharged and a second channel through which water is discharged, a first channel and a second channel branching region which are branched from the inlet channel and include an ion selective layer Wherein the ion concentration polarization phenomenon is induced in the branching region when an electric field is applied to the nano junctions. The method of claim 3,
Wherein the electric field applied to the nano-junction uses electricity generated by the ion generator. The method according to claim 1,
Wherein the thickener is arranged to separate the second solution into water and absorbent ions using a reverse osmosis membrane. The method according to claim 1,
And an absorbent regeneration section for regenerating the absorbent from the second solution that has passed through the thickening section. The method according to claim 6,
Wherein the absorbent regeneration section regenerates the absorbent by heating. The method according to claim 6,
Wherein the absorbent regeneration section separates cations contained in the absorbent by ion concentration polarization phenomenon to regenerate the absorbent. The method according to claim 1,
And the second solution passed through the thickening section is supplied again to the ion generating section. The method according to claim 1,
Further comprising a mineralization section including a vessel containing calcium and a stirring section for stirring the mixture in the vessel into which the second solution having passed through the concentrating section flows. The method of claim 3,
And the ion selective layer has a thickness of 10 to 30 占 퐉. The method of claim 3,
Wherein the ion selective layer is a porous support or a pore filling structure. The method of claim 3,
Wherein the ion selective layer is homogeneous or heterogeneous. Generating electricity by flowing a first solution into the ion generator according to claim 1; Separating the absorbing agent ions and water through the concentrated solution by passing the second solution through the ion generator; Wherein the concentration difference generation method comprises the steps of: 15. The method of claim 14,
Wherein the concentrating unit separates the second solution into absorbent ions and water through the ion concentration polarization module. 15. The method of claim 14,
Wherein the thickener separates the second solution into absorbent ions and water using a reverse osmosis membrane. 15. The method of claim 14,
And the second solution passed through the thickening section is supplied again to the ion generating section.

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