KR20210069590A - Water treatment apparatus and water treatment method using same - Google Patents

Abstract

The present invention relates to a water treatment apparatus and a water treatment method using the same. The water treatment apparatus comprises: a positive electrode; a negative electrode arranged to face the positive electrode at a distance; and one or more electrochemical units arranged at a distance from the positive electrode and the negative electrode, respectively, wherein the electrochemical unit comprises a layer which is bipolar when a voltage is applied between the positive electrode and the negative electrode. According to the present invention, ion removal efficiency in inlet water is excellent.

Description

Water treatment device and water treatment method using the same {WATER TREATMENT APPARATUS AND WATER TREATMENT METHOD USING SAME}

The present invention relates to a water treatment apparatus and a water treatment method using the same.

Recently, water shortage is emerging as an important issue in most countries around the world due to the increase in water consumption due to population growth and rapid industrialization and water pollution due to environmental pollution. In addition, it is expected that the demand for water will continue to increase due to the growth of the economy and the development of industries in the future, and the need to secure stable and innovative new water resources is emerging more than ever in preparation for a water shortage in the future.

Korea and other countries with a high potential for water shortage in the future are at a time when technological preparation is desperately needed, and among them, desalination technology is almost the only one capable of dealing with water shortage by desalination of seawater and saltwater that exist indefinitely on the earth without the influence of dry water. is a means However, in the case of evaporation and reverse osmosis desalination technologies, which currently occupy the market among desalination technologies, there is a problem in sustainability due to the high consumption of fossil fuels and the high capital cost required for plant construction. In addition, membrane-based desalination technology, like reverse osmosis desalination technology, controls the flow of water or ions to change the concentration of salt in seawater at both ends of the separation membrane. Fresh water with lower ion concentration and concentrated water with higher concentration are simultaneously generated. However, if concentrated water generated through the desalination process is discharged into the sea, it may cause eutrophication or reduce the amount of dissolved oxygen in seawater, thereby destroying the ecosystem.

One embodiment provides a water treatment device having excellent ion removal efficiency in influent and no discharge of concentrated water.

Another embodiment provides a water treatment method using the water treatment device.

According to one embodiment, it comprises a positive electrode, a negative electrode disposed to face the positive electrode at a distance, and one or more electrochemical units disposed at a distance from the positive electrode and the negative electrode, respectively, wherein the electrochemical unit, the positive electrode and Provided is a water treatment device including a layer having bipolarity when a voltage is applied between the cathodes.

The bipolar layer may include an inorganic compound, an organic compound, a mixture of an inorganic compound and an organic compound, a complex of an inorganic compound and an organic compound, or a combination thereof.

The inorganic compound may include a metal.

The metal may include a transition metal, a post-transition metal, a metalloid, or a combination thereof.

The organic compound may include carbon, a conductive polymer, or a combination thereof.

The one or more electrochemical units may further include a cation exchange membrane and/or an anion exchange membrane respectively disposed on one side or both sides facing the positive and/or negative electrode of the bipolar layer.

The cation exchange membrane is polystyrene, polyimide, polyester, polyether, polyethylene, polytetrafluoroethylene, polymethylammonium chloride, It may be an organic membrane including polyglycidyl methacrylate, or a combination thereof, a NASICON ceramic membrane, or a phosphoric acid doped PBI membrane (PA doped polybenzimidazole membrane).

The layer having the bipolarity may have a plate type, a mesh type, a compressed form of particles, a solution form including particles, or a combination thereof.

The water treatment device may include two or more electrochemical units disposed between the positive electrode and the negative electrode with a distance from each other.

The water treatment device comprises the positive electrode and the negative electrode, and one or more electrochemical units therein, wherein water is injected into the space between the positive electrode and the one or more electrochemical units and in the space between the negative electrode and the one or more electrochemical units. It may further include a housing having a water inlet for supplying, and a water outlet for discharging water discharged from the space.

According to another embodiment, while applying a voltage between the positive electrode and the negative electrode of the water treatment device according to an embodiment, water containing salt in the space between the positive electrode and the electrochemical unit and between the negative electrode and the electrochemical unit is supplied, and the cations and anions separated from the salt move to the anode and the anode in the water treatment device, respectively, and the bipolar layer in the electrochemical unit, and the supplied water is desalted. to provide.

At least one of both surfaces of the bipolar layer, and/or at least one of the surfaces facing the bipolar layer of the anode and the cathode, is a cation exchange membrane, an anion exchange membrane, or these disposed on the surface It may further include a combination of

In the method, the voltage applied between the anode and the cathode may be 0.1 V to 1,000 V.

The positive and negative ions and cations and anions migrated to the bipolar layer of the electrochemical unit may be adsorbed to the bipolar layer and/or at least one of the anode and the negative electrode.

The positive and/or negative ions and cations and/or anions migrated to the bipolar layer of the electrochemical unit and the at least one of the negative electrode and the positive electrode, and/or the layer having the bipolarity of the electrochemical unit and irreversible electricity chemical reactions can occur.

The water treatment method does not produce concentrated water.

In the method, the layer having the bipolarity may be in the form of a solution including particles or in the form of a mesh.

In the method, the solution containing the particles may be in the form of a solution containing zinc particles.

According to another embodiment, while applying a voltage between the positive electrode and the negative electrode disposed to face each other at a predetermined interval, water containing salt is supplied to the space between the positive electrode and the negative electrode, and separated from the salt in the water The cations migrate to the negative electrode, and the anions separated from the salt in the water migrate to the positive electrode, so that the migrated cations and/or anions cause an irreversible electrochemical reaction with the negative electrode and/or positive electrode, respectively, and the supply The demineralized water provides a water treatment method in which it is desalted.

In the water treatment method, an anion exchange membrane may be disposed on one surface of the positive electrode, and a cation exchange membrane may be disposed on one surface of the negative electrode.

When brine is treated with demineralized water using the water treatment device according to the present invention, concentrated water containing concentrated salt is not generated unlike conventional water treatment methods, and furthermore, the salt can be converted into high value-added inorganic metal compounds. have. Therefore, the water treatment apparatus and the water treatment method using the same according to the present invention can not only reduce environmental pollution by solving the problem of concentrated water generated during water treatment, but also provide additional economic advantages.

1 is a schematic cross-sectional view of a water treatment apparatus according to an embodiment.
2 is a schematic cross-sectional view of a water treatment apparatus according to another embodiment.
3 is a schematic cross-sectional view of a water treatment apparatus for explaining a water treatment method according to another embodiment.
4 is a real-time fluorescence brightness analysis image showing the desalting process of the water treatment apparatus according to Preparation Example 2.
5 is a graph showing the desalination performance of the water treatment apparatus according to Preparation Example 2 through real-time fluorescence brightness analysis of FIG. 4 .
6 is a graph showing the salt removal rate and energy consumption rate according to the salt concentration of the water treatment apparatus according to Preparation Example 2.
7 is a real-time fluorescence brightness analysis image showing the desalting process of the water treatment apparatus according to Preparation Example 3.
8 is a graph showing the desalination performance of the water treatment apparatus according to Preparation Example 3 through real-time fluorescence brightness analysis of FIG. 7 .
9 is a view schematically illustrating a water treatment apparatus according to Preparation Example 4, a desalination process using the same, and a process of forming and discharging a new compound generated therefrom.
10 is a view schematically illustrating a water treatment apparatus according to Preparation Example 5, a desalination process using the same, and a process of forming and discharging a new compound generated therefrom.
11 is a view schematically showing a water treatment device in which two or more electrochemical units included in the water treatment device shown in FIGS. 9 and 10 are stacked and an operation method thereof.
12 is a diagram schematically illustrating a water treatment apparatus and an operating principle thereof according to Experimental Example 4;
13 is a photograph showing the results of observing the ion depletion layer around the membrane-carbon conjugate of the water treatment device shown in FIG. 12 through an upright microscope (Axio Zoom V16, Zeiss) and an EMCCD camera (Axiocam 506 ccolor, Zeiss). .
14 is a current-voltage graph showing that, in the desalination process using the water treatment device shown in FIG. 12, the driving voltage is lowered when the same amount of ion flow (current) is present compared to the existing system.
15 is a diagram schematically illustrating a water treatment apparatus and an operating principle thereof according to Preparation Example 6. Referring to FIG.
16 shows that in the water treatment device according to Preparation Example 6, a new compound generated by reacting a cation introduced through a cation exchange membrane with a negative electrode does not dissolve in an organic solvent and is in a solid state in a channel formed between the cation exchange membrane and the negative electrode This is an electron microscope picture.
17 is a diagram schematically illustrating a water treatment apparatus and an operating principle thereof according to Preparation Example 7. Referring to FIG.

Advantages and features of the present invention, and methods of achieving them, will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only the present embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Accordingly, in some embodiments, well-known techniques have not been specifically described in order to avoid obscuring the present invention. Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular. When a part "includes" a certain component throughout the specification, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are given to the same or similar elements throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the bar shown.

When a part, such as a layer, film, region, plate, etc., is "on" another part, it includes not only the case where it is "directly on" another part, but also the case where there is another part in between. Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle.

Embodiments described herein will be described with reference to schematic diagrams, which are ideal illustrations of the present invention. Accordingly, the areas illustrated in the drawings are of schematic nature and are not intended to limit the scope of the invention.

Hereinafter, a water treatment apparatus and a water treatment method using the same according to an embodiment will be described with reference to the accompanying drawings.

1 is a cross-sectional view schematically showing the structure of a water treatment apparatus 100 according to an embodiment.

Referring to FIG. 1 , a water treatment device 100 according to an embodiment includes an anode 20 , a cathode 10 disposed to face the anode 20 at a distance from each other, and a cathode 20 and a cathode 10 . and electrochemical units 30 spaced apart from each other.

The positive electrode 20 and the negative electrode 10 are electrically connected to each other, and at least one of the positive electrode 20 and the negative electrode 10 is connected to an external power source to apply a voltage to the water treatment device 100 . The positive electrode 20 or the negative electrode 10 may include graphite, activated carbon, graphene, carbon nanotubes, carbon (nano) fibers, carbon spheres, or a combination thereof, but is not limited thereto, and is not limited thereto. It is not corroded or structurally unstable in its condition and may include any electrode forming material known in the art to be suitable for use in water treatment devices. For example, the positive electrode 20 or the negative electrode 10 may be a graphite plate or graphite foil, or may include one or more metals, metal mixtures, or alloys selected from the group consisting of Cu, Al, Ni, Fe, Co, and Ti. In addition, various types of conductors may be used as the positive electrode 20 or the negative electrode 10 .

The shape of the anode 20 or the cathode 10 is not particularly limited, and, for example, may be in the form of a thin film or plate, and may include a foam structure, a mesh structure, and the like, and is limited thereto. doesn't happen

The thickness of the anode 20 or the cathode 10 is not particularly limited and may be appropriately selected. For example, the thickness of the anode 20 or the cathode 10 is in the range of about 50 μm to 500 μm, for example, about 100 μm to 500 μm, for example, about 100 μm to 400 μm, for example, It may range from about 100 μm to 350 μm, such as from about 100 μm to 300 μm, such as from about 150 μm to 300 μm.

The electrochemical unit 30 includes a layer 30a (hereinafter also referred to as a “bipolar layer”) having bipolarity when a voltage is applied between the anode 20 and the cathode 10 . .

The layer 30a having bipolarity, when a voltage is applied through the anode 20 and the cathode 10 of the water treatment device 100, the negative and positive charges in the layer 30a are the anode 20 and the cathode ( 10) contains a material having a bipolarity through dielectric polarization towards the surface facing. Therefore, when a voltage is applied through the anode 20 and the cathode 10, the surface facing the anode 20 of the bipolar layer 30a is negatively charged, and the surface facing the cathode 10 is positively charged. can be charged. Accordingly, while applying a voltage to the water treatment device 100, between the anode 20 and the electrochemical unit 30, and between the cathode 10 and the electrochemical unit 30, seawater containing salt, etc. When passing through, under the potential gradient, salts, etc. dissociated into cations and anions contained in the seawater, etc., from seawater passing between the anode 20 and the electrochemical unit 30, the cations are electrochemically Moving toward the negatively charged surface of the bipolar layer 30a of the unit 30, the anions move toward the anode 20, from seawater passing between the cathode 10 and the electrochemical unit 30, etc. The positive ions move toward the cathode 10 , and the anions move toward the positively charged surface of the bipolar layer 30a of the electrochemical unit 30 .

Here, the cations and anions move well to the negatively charged side and the positively charged side of the bipolar layer 30a of the electrochemical unit 30, and only these cations and anions move to the electrochemical unit 30, respectively. In order to move to the corresponding surface of the bipolar layer 30a of the bipolar layer 30a, a cation exchange membrane 30b and an anion exchange membrane 30c may be formed on each corresponding surface of the bipolar layer 30a, respectively. Accordingly, the cations and anions separated from the water passing between the anode 20 and/or cathode 10 and the electrochemical unit 30 are on both sides of the bipolar layer 30a of the electrochemical unit 30, respectively. It may migrate to the negatively and positively charged surface of the bipolar layer 30a through the formed anion exchange membrane 30c and cation exchange membrane 30b. Accordingly, the electrochemical unit 30 in the water treatment device 100 according to an embodiment separates cations and anions from the salt in the water requiring treatment without applying a voltage by direct or indirect contact with an external power source and may cause migration, and the migrated cations and/or anions are adsorbed to the bipolar layer 30a in the electrochemical unit 30 or, as will be described later, irreversible in the bipolar layer 30a. It can be converted into a new compound by undergoing a hostile oxidation or reduction reaction.

On the other hand, the cation exchange membrane 30b and the anion exchange membrane 30c are disposed in contact with the surface of the bipolar layer 30a, or spaced apart from the surface of the bipolar layer 30a) at a predetermined distance. can be In the latter case, a channel may be formed between the bipolar layer 30a) and the cation exchange membrane 30b and/or between the bipolar layer 30a) and the anion exchange membrane 30c, respectively. In this case, a solution containing particles of a material forming a bipolar layer, a non-aqueous organic solvent, an electrolyte, and the like, which will be described later, may pass through the formed channel. In this case, as will be described later, anions and/or cations introduced through the cation exchange membrane 30b and/or the anion exchange membrane 30c form the bipolar layer 30a and/or the bipolar layer. particles of or a new inorganic compound formed by an irreversible electrochemical reaction with an electrolyte or inorganic compound introduced through the channel can also be easily discharged to the outside through this channel.

The cation exchange membrane 30b is, for example, polystyrene, polyimide, polyester, polyether, polyethylene, polytetrafluoroethylene, polymethyl It may be an organic film including ammonium chloride, polyglycidyl methacrylate, or a combination thereof, but is not limited thereto.

Alternatively, the cation exchange membrane 30b is a ceramic membrane that does not pass water, for example, sodium that allows only sodium ions to pass between the layer 30a having bipolarity in the electrochemical unit 30 and water containing ions. , zirconium, silicon, phosphorus and the like, ie, a so-called NASICON ceramic film (Na _1+x Zr ₂ Si _x P _3-x O ₁₂ , x=2). Since the NASICON ceramic membrane does not pass water, as will be described later, the cations introduced through the membrane cause an irreversible electrochemical reaction with the bipolar layer 30a, and the reactivity with water among materials that can be generated is high. It can hold large materials stably. The stably maintained product may then be separated and converted into a new compound having a high added value, with or without a post-treatment process. For example, when the product is sodium ^{hydride (NaH) produced by a chemical reaction between sodium (Na +} ) ions and hydrogen ions separated from water, a channel formed between the bipolar layer 30a and the cation exchange membrane Trimethylborate as a non-aqueous electrolyte is injected through the cation exchange membrane and a hot wire is inserted between the bipolar layer 30a of the electrochemical unit, and the generated NaH is synthesized and simultaneously synthesized as sodium borohydride (NaBH ₄ ) may be converted. Such sodium borohydride is a high value-added compound with many industrial uses. Accordingly, the water treatment method according to an embodiment provides a new method capable of producing high value-added compounds without generating concentrated water, unlike the conventional water treatment method of generating concentrated water as a by-product.

Meanwhile, in addition to the NASICON ceramic membrane, a phosphoric acid-doped polybenzimidazole (PBI) membrane may be used as the cation exchange membrane 30b that does not pass water, and the cation exchange membrane is not limited thereto.

The cation exchange membrane 30b may be a combination of the organic membrane and the inorganic membrane, or an organic/inorganic composite membrane.

The anion exchange membrane 30c may include, for example, polysulfone (PSF), polyether sulfone (PES), or a combination thereof, but is not limited thereto.

The bipolar layer 30a may include an inorganic compound, an organic compound, a mixture of an inorganic compound and an organic compound, a complex of an inorganic compound and an organic compound, or a combination thereof.

The inorganic compound may be a metal, a non-metal, or a combination thereof.

The metal may be a transition metal, a post-transition metal, a metalloid, or a combination thereof.

The transition metal is scandium (Sr), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), yttrium (Y), zirconium (Zr), molybdenum (Mo), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), hafnium (Hf) , tungsten (W), iridium (Ir), platinum (Pt), gold (Au), or a combination or alloy thereof.

The post-transition metal may include aluminum (Al), gallium (Ga), indium (In), tin (Sn), thallium (Tl), lead (Pb), bismuth (Bi), or a combination or alloy thereof. and, for example, the metal after the transition may include aluminum (Al), or a mixture or alloy of a metal containing the same.

The metalloid may include, but is not limited to, silicon (Si), germanium (Ge), antimony (Sb), telerium (Te), or a combination thereof.

The organic compound may include, but is not limited to, carbon, a conductive polymer, or a combination thereof.

The carbon refers to a material whose main component consists of carbon atoms, and may have a compound form combined with other elements in addition to carbon alone. For example, the carbon may be carbon fiber, graphite, carbon nanomaterial, or a combination thereof made of carbon alone, and the carbon nanomaterial includes carbon nanotubes, graphene, carbon nanoplates, fullerene, and the like, and is limited thereto. doesn't happen

The conductive polymer is, for example, polypyrrole, polythiophene, polyaniline, polyacetylene, polyphenylene sulfide, polyphenylenevinylene, polyindole, polypyrene. One compound or two or more selected from polycarbazole, polyazulene, polyazepine, polyfluorene, polynaphthalene, poly3,4-ethylenedioxythiophene-polystyrenesulfonate (PEDOT-PSS) and polyethylenedioxythiophene It may be a mixture, but is not limited thereto.

The layer 30a having the bipolarity may include a plate type, a mesh type, a compressed particle slurry of the inorganic compound or the organic compound, and the particle slurry of the inorganic compound or the organic compound. It may be in the form of a solution comprising a, or a combination thereof. For example, the bipolar layer 30a may include at least one metal plate, or a combination of two or more different metal plates. Alternatively, the bipolar layer 30a may be at least one metal mesh, or may include a combination of two or more different metal meshes. Alternatively, the bipolar layer 30a may include one or more plates including an inorganic compound on which the metal is plated, or one or more plates including a combination of two or more different inorganic compounds on which the metal is plated. may include Alternatively, the layer 30a having the bipolarity may include at least one in which the metal is plated on the surface of the inorganic compound in the form of a mesh. For example, the bipolar layer 30a may include carbon fibers in the form of a plate or a mesh. Alternatively, the layer 30a having the bipolarity may be in the form of a plate or a mesh in which a slurry containing carbon nanomaterials is compressed. Alternatively, the bipolar layer 30a may be a combination of a metal plate and a solution containing metal particles or other metal particles forming the metal plate. In this case, as described above, although in FIG. 1 , the layer 30a having bipolarity, the cation exchange membrane 30b and the anion exchange membrane 30c formed thereon are each formed on the surface of the layer 30a having the bipolarity and Although it is shown as being disposed in a contact state, it is not necessarily limited thereto, and the cation exchange membrane 30b and the anion exchange membrane 30c are spaced apart from both surfaces of the bipolar layer 30a by a predetermined distance. By being able to, in this case, the bipolar layer through a channel formed between the layer 30a and the cation exchange membrane 30b having bipolarity and/or between the layer 30a having the bipolarity and the anion exchange membrane 30c When the forming material, for example, the bipolar material is a metal, a solution containing the metal particles and/or other metal particles may pass therethrough. In this case, as described in detail in Examples to be described later, when the ions and the metal particles flowing through the ion exchange membrane toward the bipolar layer 30a cause an irreversible electrochemical reaction to generate a new compound, the product is There is an advantage that can be easily separated through the channel. In addition, in this case, in the continuous water treatment process, when the bipolar layer 30a and the metal particles are the same material, the bipolar layer 30a is formed by a continuous irreversible reaction with ions separated from water. The exhaustion problem can also be solved. On the other hand, when the liquid flowing through the channel is an organic solvent, the organic solvent does not mix with water even if a separate electrolyte or a material forming the bipolar layer is not included in the solvent. There may be an advantage in that the material generated by the irreversible developing chemical reaction between the separated ions and the bipolar layer 30a can be easily discharged to the outside.

In one embodiment, the bipolar layer 30a may include zinc, and in this case, the bipolar layer 30a is a zinc plate together with the bipolar layer 30a and a cation exchange membrane ( 30b) may be in a form including a solution containing zinc particles in the channel formed between them. When the bipolar layer 30a contains a solution containing zinc particles, a solution containing zinc particles is applied between the bipolar layer 30a and the cation exchange membrane 30a while operating the water treatment device. By continuously supplying to the channel formed in the bipolar layer 30a is depleted, or a product produced by a chemical reaction between the ^{bipolar layer 30a and ions, for example, chlorine ions (Cl − ),} For example, _{the problem that ZnCl 2} is attached to the surface of the bipolar layer 30a and the irreversible electrochemical reaction is slowed can also be solved. In addition, _{it is advantageous to recover the generated ZnCl 2} from the water treatment device.

The thickness of the layer 30a having bipolarity is not particularly limited and may be appropriately selected. For example, the thickness of the bipolar layer 30a is in the range of about 100 μm to 1,000 μm, for example, about 150 μm to 800 μm, for example, about 150 μm to 700 μm, for example, about 200 μm to 600 μm, such as about 200 μm to 500 μm, such as about 250 μm to 500 μm.

In one embodiment, the bipolar layer 30a of the electrochemical unit 30 in the water treatment device according to an embodiment contains aluminum (Al), and a salt such as NaCl is present in the water requiring treatment. ^{In this case, redox reactions of chlorine ions (Cl −} ) and sodium ions (Na ⁺ ) may occur on both surfaces of the bipolar layer 30a, respectively.

Specifically, as described above, in the layer 30a having bipolarity according to voltage application, the surface facing the cathode 10 is positively charged, and the surface facing the anode 20 is negatively charged. Therefore, when Cl ⁻ ions flow into the positively charged surface, they lose electrons through a reaction with Al metal and water in the bipolar layer 30a to generate _{aluminum chloride hydroxide (Al 2} Cl(OH) _{5 ).} ^{When Na +} ions are introduced into the negatively charged side of the bipolar layer 30a, they receive electrons while reacting with Al metal and water in the bipolar layer 30a and sodium aluminum hydride (NaAlH _{4 )} ) can be converted into a reduction reaction. As described above, in the water treatment apparatus 100 according to an embodiment, the cations and anions separated from the salt in water move to both surfaces of the layer 30a having bipolarity in the electrochemical unit 30, respectively, and adsorb it as well. , as will be described later, depending on the voltage applied between the positive electrode 20 and the negative electrode 10, each can be converted into a new type of compound through an electrochemical reaction on the surface. The compounds thus produced are present in or on the surface of the bipolar layer 30a, and/or the bipolar layer 30a and the cation exchange membrane 30b and/or the bipolar layer 30a and the anion exchange membrane (30c) exists in the channel formed between, and the formation reaction of these compounds is an irreversible reaction, so the formed compounds are not converted back to the original ions or salts. Therefore, the water treatment method using the water treatment device 100 according to one embodiment removes the salt contained in the water to be treated and discharges the demineralized water, and unlike the existing desalination techniques such as reverse osmosis or electrodialysis, separated salt or It may not produce an ion-concentrated brine. Accordingly, the water treatment method using the water treatment device according to the exemplary embodiment has an effect of reducing additional costs and/or environmental pollution problems for the treatment of concentrated water. Furthermore, the generated compounds may be inorganic metal compounds with high economic value, and thus, the water treatment method according to an embodiment can not only improve water shortage by desalination of seawater, etc., but also inorganic metals with high economic value. It may also provide the added benefit of providing a compound.

The water treatment device 100 according to an embodiment further includes a housing 50 containing the anode 20 and the cathode 10 and the electrochemical unit 30 disposed between the anode 20 and the cathode 10 . may include In the housing 50, a water inlet (not shown) for supplying water requiring treatment to the passage 40, which is a space between the electrodes 10 and 20 and the electrochemical unit 30, and treated water A water outlet (not shown) for discharging may be provided. For example, the water inlet and the water outlet may be disposed on opposite sides at both ends in the longitudinal direction parallel to the electrodes 10 and 20 and the electrochemical unit 30 of the water treatment device according to an embodiment. have. In one embodiment, while applying a voltage to the water treatment device 100 , water requiring treatment, for example, water containing salt, is injected through the water inlet, and the water moves along the flow path 40 . Accordingly, the salt contained in the water is separated into cations and anions by an electric field, and the separated cations and anions are, as described above, the surfaces of the negative electrode 10 and the positive electrode 20, respectively, and the electrochemical unit 30 ) can be removed by adsorption on both sides of the inner bipolar layer 30a. In another embodiment, the cations and anions migrated to the bipolar layer 30a of the electrochemical unit 30 are bipolar, respectively, by irreversible oxidation and reduction reactions represented by Schemes 1 and/or Schemes 2 described above. A new compound may be formed by reacting with a material forming the polar layer 30a and/or a material present in a channel formed between the bipolar layer 30a and the ion exchange membrane. The produced compound may be an inorganic metal compound, and these compounds may be discharged without forming concentrated water.

On the other hand, although FIG. 1 illustrates a case in which one electrochemical unit 30 is present between the positive electrode 20 and the negative electrode 10, two or more electrochemical units are disposed between a pair of electrodes in one embodiment. It is also possible to configure a water treatment device according to the. A schematic diagram of a water treatment apparatus including a plurality of electrochemical units arranged in parallel with a distance from each other between a pair of electrodes is shown in FIG. 2 .

Referring to FIG. 2 , the water treatment device 200 includes three electrochemical units 30 arranged in parallel with an interval between the anode 20 and the cathode 10 . The three electrochemical units 30 are arranged in parallel with each other, respectively, parallel to the movement path of the water to be treated. As shown in FIG. 2 , when two or more electrochemical units are disposed in parallel and included, the contact surface or contact space between the water to be treated and the electrochemical unit 30 is widened in proportion to the number of the disposed electrochemical units. Therefore, the water treatment amount and the treatment speed may be increased in proportion to the number of electrochemical units to be disposed. When two or more electrochemical units are connected in parallel, when a voltage is applied between the anode 20 and the cathode 10, by an electric field effect, the anode among both sides of the bipolar layer 30a included in each electrochemical unit All of the one surface facing (20) may be negatively charged, and the other surface facing the negative electrode (10) may be all positively charged. Therefore, the salts in the water passing through the flow path 40 between the electrochemical units 30 are separated into positive and negative ions, and pass through the space to the negatively charged surface and positive charge of the adjacent electrochemical unit 30, respectively. It can migrate to the charged surface and be adsorbed.

As in FIG. 1 , water passing through the flow path 40 between the anode 20 and the electrochemical unit 30 or the flow path 40 between the cathode 10 and the electrochemical unit 30 is water The cations and anions separated from the salt present in the anode 20 and the cathode 10, respectively, and the surface of the bipolar layer 30a of the electrochemical unit 30 are charged with opposite charges to the corresponding cations and anions It can be separated by moving to the surface of the As such, in the water treatment device 200 including two or more electrochemical units 30 , the anode 20 and the cathode 10 , and the adsorption of ions separated from the salt on the surface of each electrochemical unit 30 , and Since / or irreversible electrochemical reaction may occur, the water treatment amount, treatment speed and efficiency may be maximized.

In the water treatment apparatus 100 or 200 according to an embodiment, at least one of the positive electrode 20 or the negative electrode 10 is connected to an external power source and serves to apply a voltage to the water treatment apparatus 100 or 200 . At this time, the other electrode may be grounded.

The voltage applied between the positive electrode 20 and the negative electrode 10 may be 0.1 V to 1,000 V, for example, 1 V to 1,000 V, for example, 5 V to 1,000 V, for example, 10 V to 1,000 V, such as 10 V to 900 V, such as 10 V to 800 V, such as 10 V to 700 V, such as 10 V to 600 V, such as 10 V to 500 V, such as 20 V to 500 V, such as 30 V to 500 V, such as 50 V to 500 V, such as 100 V to 500 V, such as 100 V to 400 V, eg, 100 V to 300 V, eg, 100 V to 250 V, or eg, 150 V to 250 V, but is not limited to these ranges.

When the applied voltage is less than 0.1 V, a sufficient electric field for water treatment may not be formed. That is, the separation of the salt in the water to be treated into ions, the migration of these ions to the oppositely charged positive electrode or negative electrode, and/or the surface of the bipolar layer, adsorption, and removal are poor, and the water treatment efficiency is significantly reduced. can do.

Even when including two or more electrochemical units 30, the voltage applied between the positive electrode 20 and the negative electrode 10 may be 0.1 V to 1,000 V, for example, 1 V to 1,000 V, for example, For example, 5 V to 1,000 V, such as 10 V to 1,000 V, such as 10 V to 900 V, such as 10 V to 800 V, such as 10 V to 700 V, such as For example, 10 V to 600 V, such as 10 V to 500 V, such as 20 V to 500 V, such as 30 V to 500 V, such as 50 V to 500 V, such as , 100 V to 500 V, such as 100 V to 400 V, such as 100 V to 300 V, such as 100 V to 250 V, or for example, 150 V to 250 V. may be, but are not limited to these ranges.

On the other hand, in the water treatment apparatus 100 or 200 according to an embodiment, when an irreversible electrochemical reaction takes place in the electrochemical unit 30a with the separated cations and anions, the cations and anions are simply added to the surface of the electrochemical unit. A higher voltage range may be required than for adsorption. Accordingly, in order to prevent an irreversible electrochemical reaction through the water treatment method according to an embodiment, thereby not generating concentrated water containing separated ions or salts, a voltage of at least about 0.1 V may be applied. On the other hand, when the applied voltage exceeds 1,000 V, there may be problems such as side reactions such as electrolysis of influent water at the anode 20 or the cathode 10 .

In the water treatment device 100 or 200 according to an embodiment, when a voltage is applied between the anode 20 and the cathode 10, the cations and water molecules separated from the salt in the water move in the direction of the electric field, and electrochemical The negatively charged surface of the bipolar layer 30a is reached through the cation exchange membrane 30b of the unit 30 . At this time, the cation is a new compound by a reduction reaction receiving electrons from the negative charge of the bipolar layer 30a, for example, when the bipolar layer 30a is made of a metal, it is synthesized as an inorganic metal compound. can These inorganic metal compounds may be converted into various inorganic metal compounds according to the type of metal forming the bipolar layer 30a in the electrochemical unit 30 and/or the type of salt present in water. Accordingly, in order to obtain a desired inorganic metal compound using the water treatment apparatus and the water treatment method according to an exemplary embodiment, the type of metal forming the bipolar layer 30a may be selected. Accordingly, the inorganic metal compound that can be synthesized by the reduction reaction as described above may be represented by the following Chemical Formula 1 or the following Chemical Formula 2, but is not limited thereto.

[Formula 1]

C _x M _y O _z (1≤x≤3, 1≤y≤3, 1≤z≤7)

[Formula 2]

C _x M _y H _z (1≤x≤3, 1≤y≤3, 1≤z≤7)

In Formula 1 and Formula 2,

C is selected from the group consisting of Li, Na, K, Rb, Be, Mg, Ca, Sr, Ba, and combinations thereof,

M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, selected from the group consisting of Al, Zn, Ga, Cd, In, Sn, Ti, Pb, Bi, Po, Si, Ge, As, Sb, Te, and combinations thereof,

O is oxygen and H represents hydrogen.

On the other hand, in the water treatment apparatus 100 or 200 according to an embodiment, when a voltage is applied between the anode 20 and the cathode 10, the anions and water molecules separated from the salt in the water move in the opposite direction of the electric field. and reaches the positively charged surface of the bipolar layer 30a through the anion exchange membrane 30c of the electrochemical unit 30 . At this time, the anion is a new compound by an oxidation reaction that provides electrons to the positive charge of the bipolar layer 30a, for example, an inorganic metal compound generated by a reduction reaction between the cation and the bipolar layer 30a. It can be synthesized as a second inorganic metal compound different from Such an inorganic metal compound may also be converted into various inorganic metal compounds according to the type of metal forming the bipolar layer 30a. For example, the inorganic metal compound that may be produced by the reduction reaction may be represented by the following Chemical Formula 3, but is not limited thereto:

[Formula 3]

A _x M _y O _z (1≤x≤3, 1≤y≤3, 1≤z≤7)

In Formula 3,

A is selected from the group consisting of Li, Na, K, Rb, Be, Mg, Ca, Sr, Ba, and combinations thereof,

M is Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, Ir, Pt, Au, selected from the group consisting of Al, Zn, Ga, Cd, In, Sn, Ti, Pb, Bi, Po, Si, Ge, As, Sb, Te, and combinations thereof;

O means an oxygen atom.

That is, the water treatment apparatus 100 or 200 according to an embodiment is an irreversible electrochemical reaction on both surfaces of the electrochemical unit 30, for example, through an oxidation reaction and/or a reduction reaction, Al ₂ Cl(OH). ) ₅ , NaAlH _4, etc. can be synthesized, and these inorganic metal compounds are produced by adsorption on the inside or surface of the bipolar layer of the electrochemical unit, and unlike conventional reverse osmosis or electrodialysis methods, salt or It may not produce an ion-concentrated brine. In addition, the produced compound may be an inorganic metal compound of high added value, such as _{Al 2} Cl(OH) ₅ , NaAlH _{4 , and the like.}

In the water treatment device 200 including two or more electrochemical units 30 between the anode 20 and the cathode 10 as in FIG. 2 , as in FIG. 1 , the bipolarity of the electrochemical unit 30 . The cation exchange membrane 30b and the anion exchange membrane 30c located on both sides of the layer 30a having can be formed is the same. It is also possible to supply an organic solvent, particles of a material forming the bipolar layer 30a, and/or a solution containing other inorganic compounds through these channels. In addition, the configuration of the anode 20 and the cathode 10, the bipolar layer 30, and the housing 50 including them are the same as those described with reference to FIG. 1, and thus a detailed description thereof will be omitted.

Meanwhile, in FIGS. 1 and 2, a water treatment device including one or more electrochemical units 30 between a pair of electrodes and a water treatment method using the same have been described, but in another embodiment of the present invention, the anode 20, and a negative electrode 10 disposed to face the positive electrode 20 at a distance from each other, and comprising an anion exchange membrane 20b and a cation exchange membrane 10b on the positive electrode 20 and the negative electrode 10, respectively Using the water treatment device 300, a method of treating water according to the same principle is also provided (see FIG. 3 ).

Specifically, the water treatment method using the water treatment device of FIG. 3 does not include the electrochemical unit 30 between the pair of electrodes, as compared with the water treatment device of FIGS. 1 and 2 , but instead the pair of electrodes itself When a voltage is applied, it acts like the bipolar layer 30a of FIG. 1 , so it is different in that it includes a cation exchange membrane 10b and an anion exchange membrane 20b on the negative electrode and the positive electrode, respectively, and its action The principle is substantially the same as the water treatment method described in FIGS. 1 and 2 .

Specifically, referring to FIG. 3, while applying a voltage between the anode 20 and the cathode 10, when the water to be treated passes through the space between the anode 20 and the cathode 10, The salt contained in the water is separated into cations and anions by the electric field, the separated cations move to the negative electrode 10 through the cation exchange membrane 10b, and the separated anions are transferred to the positive electrode ( 20) can be moved.

Here too, between the cation exchange membrane 10b and the negative electrode 10 and between the anion exchange membrane 20b and the positive electrode 20 are not in close contact, but are spaced apart at a predetermined distance to form channels 10a and 20a. . In this case, the migrated anions and cations are adsorbed on the surfaces of the anode 20 and the cathode 10, respectively, or after adsorption, the anode and the cathode, or the material present in the channels 10a and 20a, and irreversible electricity A chemical reaction occurs, and as a result, the produced material may be present in the channels 10a and 20a, or may be discharged to the outside through these channels. In addition, water passing through the space 40 between the positive electrode 20 and the negative electrode 10 may be desalted and discharged, and even in this method, concentrated water containing ions or salts is not generated.

The positive electrode 20, the negative electrode 10, the anion exchange membrane 20b, and the cation exchange membrane 10b of the water treatment device according to the embodiment are the same as those described in the above embodiment. As described above, a slurry of a material for forming an anode or a cathode through the channels 10a and 20a formed between the cation exchange membrane 10b and the cathode 10 and between the anion exchange membrane 20b and the anode 20 may be supplemented, and the product produced by the irreversible reaction of the cation or anion separated from water and the cathode or anode in this channel may be stably stored. At this time, as described above, by using a NASICON or PA-doped PBI membrane that allows only the movement of sodium (Na+) ions and does not pass water as the cation exchange membrane 10b, NaH with high reactivity with water, etc. can also be maintained as

In one embodiment, the anode 20 may be made of a zinc thin film, and the cathode 10 may be made of carbon, for example, graphite foil. At this time, in order to prevent consumption of the zinc thin film used as the anode 20 , an aqueous solution containing zinc particles may be injected into the channel 20a existing between the anion exchange membrane 20b and the anode 20 . In addition, by injecting an organic solvent immiscible with water into the channel, the cations and anions separated from the water move to the negative electrode or the positive electrode through the ion exchange membrane, and then an irreversible electrochemical reaction with the negative electrode or the positive electrode is performed. A new inorganic compound is produced, and the produced material can be easily discharged to the outside of the water treatment device together with the organic solvent.

In one embodiment, when a brine containing sodium chloride (NaCl) is passed while applying a voltage to a device using a zinc thin film as the anode 20 and a graphite foil as the cathode 10, sodium in the brine ( Na ⁺ ) ions pass through the NASICON membrane and move toward the graphite foil, and chlorine (Cl ⁻ ) ions pass through the anion exchange membrane and move toward the zinc thin film. At this time, when the applied voltage is adjusted so that the sodium ion and the chlorine ion cause an irreversible reaction with the negative electrode and the positive electrode, respectively, the sodium ion combines with the hydrogen ion to produce NaH, and the chlorine ion reacts with zinc ZnCl ₂ may be produced. At this time, the generated NaH has a high reactivity with water, but water is blocked by the NASICON membrane, so that NaH can be stably maintained in the membrane. The NaH maintained in this way can be converted into _{sodium borohydride (NaBH 4} ), which is a high value-added metal compound through a separate post-treatment. The separate post-treatment process _{may be made by reacting trimethylborate (B(OCH 3} ) ₃ ) with sodium hydride (NaH).

In another embodiment, the positive electrode 20 and/or the negative electrode 10 may each be configured in a mesh shape. In this case, the positive electrode 20 and/or the negative electrode 10 may be manufactured by directly adhering to the anion exchange membrane and/or the cation exchange membrane, respectively, and such a water treatment device has the effect of reducing resistance. In this case, a channel may be formed by leaving a gap between the opposite side of the positive electrode and/or negative electrode bonded to the ion exchange membranes and each current collector, and an organic solvent, a non-aqueous electrolyte, or the positive electrode or negative electrode may be formed in the channel. A solution containing a material that forms In this case, a new compound may be generated by reacting the ions separated from the water with the anode and/or cathode in the form of a mesh, or a material in the channel, and the new compound generated in this way is easily released to the outside through the channel. It can also be ejected.

The water treatment apparatus and water treatment method can be used in various ways in the process of separating and purifying ionic substances as well as desalination of seawater, for example, a water softening process, a nitrate nitrogen removal process, and recovery of valuable metals in plating wastewater. Its usefulness can be found in various fields such as process, heavy metal removal process, and water treatment process.

Hereinafter, specific embodiments of the present invention are presented. However, the examples described below are only for specifically illustrating or explaining the invention, and the present invention should not be limited thereto.

(Example)

Preparation Example 1. Preparation of water treatment device

ASTOM's Neosepta CMX as a cation exchange membrane was attached to one side of a 250 μm thick aluminum thin film, and ASTOM's Neosepta AMX was attached as an anion exchange membrane to the other side, and then engraved into a width of 0.5 mm and a length of 20 mm, A chemical unit, a Membrane-Membrane Assembly (MMA), is prepared.

Next, in the same manner as in the above film-metal assembly, two graphite foils engraved with a width of 0.5 mm and a length of 20 mm were prepared for a graphite foil having a thickness of 370 μm, and used as a cathode and an anode, respectively.

On the other hand, a lower housing made of a transparent polydimethylsiloxane (PDMS) material in which the engraved film-metal assembly, the anode and the cathode are each provided at a predetermined distance and inserted to the same depth to be fixed and arranged in parallel. In the above, the prepared positive electrode and negative electrode are inserted into grooves formed at both ends, respectively, and the film-metal assembly is fixed in the center groove formed with the same spacing of 1 mm from the positive electrode and the negative electrode, respectively, and then fixed in the same form Manufactured, the anode, the cathode, and the opposite ends of the membrane-metal assembly are fitted to the same depth and fixed by covering the upper housing made of a transparent polydimethylsiloxane (PDMS) material and fixing the upper housing through plasma treatment. The water treatment device is manufactured by joining the lower housing and the lower housing. At this time, in the water treatment device, the upper housing and the lower housing, and the anode and the film-metal so that water can pass through between the anode and the membrane-metal assembly and between the cathode and the membrane-metal assembly A certain volume of empty space, ie, a channel, is formed between the conjugate and the cathode and the film-metal assembly. In addition, a water inlet for introducing water to be treated into the channels is formed in the upper housing, and a water outlet for discharging water discharged through the channels is formed in the lower housing.

Preparation Example 2. Preparation of water treatment device

A water treatment device is manufactured in the same manner as in Preparation Example 1, but unlike in Preparation Example 1, a membrane-electrochemical unit between the anode and the cathode is prepared, a water treatment device including three metal assemblies.

That is, among the five grooves formed in the lower housing made of transparent polydimethylsiloxane, the graphite foil, which is a positive electrode and a negative electrode, is inserted into the grooves at both ends, respectively, and the same interval (about 2 mm interval) is placed between the positive and negative electrodes, respectively. After inserting and fixing the three film-metal assemblies to be used, the upper housing made of transparent polydimethylsiloxane manufactured in the same shape is covered on the upper housing and plasma-treated to manufacture a water treatment device.

Preparation Example 3: Preparation of a water treatment device

A water treatment device was manufactured in the same manner as in Preparation Example 2, but instead of a membrane-metal assembly (MMA) as an electrochemical unit, a membrane-carbon assembly (MCA) was used to prepare a water treatment device.

Specifically, the membrane-carbon conjugate was prepared by attaching ASTOM's Neosepta CMX grade as a cation exchange membrane to one side of an activated carbon fiber having a thickness of 500 μm, and ASTOM's Neosepta AMX grade as an anion exchange membrane to the other side. .

Using the membrane-carbon assembly prepared above and the graphite foil as prepared in Preparation Example 1 as an electrochemical unit and an anode and a cathode, respectively, in the same manner as in Preparation Example 2, a lower housing and an upper housing made of polydimethylsiloxane. to fabricate a water treatment device.

Experimental Example 1

In order to measure the performance of the water treatment device prepared in Preparation Example 2, a mixture of 10 mM NaCl aqueous solution and a fluorescent material (Alexa488, Invitrogen) was added at a flow rate of 20 μl/min through the water inlet formed in the upper housing of the water treatment device. inject At this time, a voltage of 30 V (Keithley 2461, Keithley Instrument) was applied to the carbon electrode of the device, and the mixture was continuously injected into the water inlet using a hydraulic pump (Fusion 200, Revodix), and at the same time water Allow the treated water to be discharged through the outlet.

The ion depletion layer around the membrane-metal conjugate of the water treatment device was observed through an inverted microscope (IX-73, Olympus) and an EMCCD camera (Image X2, Hamamatsu), and the results are shown in FIG. 4 .

As a result of checking the real-time desalination performance as shown in the right photo of FIG. 4 , it can be confirmed that the ion depletion layer appears black around the membrane-metal junction in the water passing through the water treatment device.

In addition, when the water mixed with the fluorescent dye is moved without applying a voltage to the water treatment device, that is, when the voltage is 0 V and when a voltage of 30 V is applied, the water mixed with the fluorescent dye is moved In this case, the result of analyzing the fluorescence dye according to the position between the membrane-metal conjugate in the water treatment device using the ImageJ (NIH, USA) program is shown in FIG. 5 .

As can be seen from FIG. 5 , when no voltage is applied to the water treatment device, that is, when it is 0 V, the concentration of the fluorescence dye is not significantly affected by the position of the membrane-metal complex in the water treatment device and the overall concentration of the fluorescent dye is similar or has a special tendency In contrast to this, when a voltage of 30 V is applied to the water treatment device, it can be seen that the concentration of the fluorescent dye in the vicinity of the membrane-metal junction is significantly lower than in the central part. That is, the ions that were bound to the fluorochrome due to voltage application move toward the membrane-metal junction and are separated from the fluorochrome, and the concentration of the fluorochrome decreases in the vicinity of the membrane-metal junction, whereas the ions far from the membrane-metal junction It can be seen that the concentration of the fluorescent dye is high in the central part. That is, it can be seen that by applying a voltage to the water treatment apparatus according to Preparation Example 2, ions in the water move toward the membrane-metal assembly and desalination is performed.

On the other hand, as shown in Table 1 below, the NaCl aqueous solution was continuously injected using a hydraulic pump (Fusion 200, Chemyx) into the water treatment device prepared in Preparation Example 2 while varying the concentration, flow rate, and applied voltage of the NaCl aqueous solution. , to evaluate the salt removal rate and energy consumption rate according to the concentration of the NaCl aqueous solution, and the results are shown in FIG. 6 .

The salt removal rate was calculated by Equation 1 below, where the electrical conductivity of the water outlet of the water treatment device was measured using an electrical conductivity meter (Orionstar A325, Thermo Scientific).

[Equation 1]

salt removal (%) = 1 - (electric conductivity of water outlet / electrical conductivity of water inlet) * 100

Concentration of NaCl aqueous solution (ppm) flow rate (μl/min) Applied voltage (V) Current (A) 700 10 10 0.00005 7,000 30 15 0.0011 35,000 30 30 0.003 70,000 50 30 0.01

Referring to FIG. 6 , the removal rate of NaCl from the aqueous NaCl solution using the water treatment device shows a salt removal rate of 90% or more even with low energy when the concentration of NaCl is low, and salts of 80% or more even when the concentration of NaCl is very high. It can be seen that the removal rate is represented. However, it can be seen that the higher the salt concentration, the higher the required energy consumption.

Experimental Example 2

In order to measure the performance of the water treatment device prepared in Preparation Example 3, a mixture of 10 mM NaCl aqueous solution and a fluorescent material (Alexa488, Invitrogen) was added through a water inlet formed in the upper housing of the water treatment device at a flow rate of 20 μl/min. inject At this time, a voltage of 40 V (Keithley 2461, Keithley Instrument) was applied to the carbon electrode of the device, and the mixture was continuously injected into the water inlet using a hydraulic pump (Fusion 200, Revodix), and at the same time water Allow the treated water to be discharged through the outlet.

The ion depletion layer around the membrane-carbon conjugate of the water treatment device according to Preparation Example 3 was observed through an upright microscope (Axio Zoom V16, Zeiss) and an EMCCD camera (Axiocam 506 ccolor, Zeiss), and the results are shown in FIG. indicates.

As a result of checking the real-time desalination performance as shown in the photo on the right of FIG. 7 , it can be confirmed that the ion depletion layer appears black around the membrane-carbon conjugate in the water passing through the water treatment device.

In addition, when the water mixed with the fluorescent dye is moved without applying a voltage to the water treatment device, that is, when the voltage is 0 V and when a voltage of 40 V is applied, the water mixed with the fluorescent dye is moved In this case, the result of analyzing the fluorescence dye according to the position between the membrane-carbon conjugates in the water treatment device using the ImageJ (NIH, USA) program is shown in FIG. 8 .

As can be seen from FIG. 8, when no voltage is applied to the water treatment device, that is, when it is 0 V, the concentration of the fluorescence pigment is not significantly affected by the position of the membrane-carbon conjugate in the water treatment device, and the concentration of the fluorescence pigment is similar or has a special tendency. In contrast to this, when a voltage of 40 V is applied to the water treatment device, it can be seen that the concentration of the fluorescent dye in the vicinity of the membrane-carbon conjugate is significantly lower than in the central part. That is, the ions that were bound to the fluorochrome due to the voltage application move toward the membrane-carbon conjugate and are separated from the fluorochrome, and the concentration of the fluorochrome decreases in the vicinity of the membrane-carbon junction, whereas the ions away from the membrane-carbon junction decrease. It can be seen that the concentration of the fluorescent dye is high in the central part. That is, it can be seen that by applying a voltage to the water treatment apparatus according to Preparation Example 3, ions in the water move toward the membrane-carbon conjugate to be desalted.

Preparation Example 4. Preparation of water treatment device

A 230 ㎛-thick zinc thin film and a 370 ㎛-thick graphite foil are equally engraved to 0.5 mm in width and 20 mm in length to serve as an anode and a cathode, respectively. In this case, the negative electrode is not limited to the graphite foil and may be replaced with a comprehensive electrode.

Next, a 1 mm thick NASICON membrane is used as a cation exchange membrane, and Neosepta AMX manufactured by ASTOM is engraved into a width of 0.5 mm and a length of 20 mm as an anion exchange membrane.

Next, the carved cation exchange membrane, the anion exchange membrane, the positive electrode, and the negative electrode are respectively inserted at a predetermined distance and at the same depth to be fixed and arranged in parallel with four grooves formed of a transparent polydimethylsiloxane (PDMS) material. The lower housing and the upper housing made of transparent polydimethylsiloxane (PDMS) material manufactured in the same shape and formed so that the cation exchange membrane, the anion exchange membrane, and the opposite ends of the anode and the cathode can be inserted and fixed at the same depth are chemically treated with 30 μL of silane It is coated through a chemical vapor deposition (CVD) process.

The carved positive electrode and the negative electrode are fitted into grooves formed at both ends of the lower housing, and the carved anion exchange membrane is fixed by fitting the carved anion exchange membrane into the groove formed at a distance of 1 mm from the positive electrode, and a groove formed at a distance of 1 mm from the negative electrode. Insert the fragmented cation exchange membrane to fix. At this time, the cation exchange membrane and the anion exchange membrane are positioned between the anode and the cathode, and the distance between the two exchange membranes is about 1 mm. After covering and fixing the upper housing made of a transparent polydimethylsiloxane (PDMS) material manufactured in the same form and formed so that the opposite ends of the anode, the cathode, the cation exchange membrane, and the anion exchange membrane can be fixed by being inserted at the same depth, plasma treatment A water treatment device is manufactured by joining the upper and lower housings through the At this time, in the water treatment device, a zinc chloride aqueous solution is passed between the positive electrode and the anion exchange membrane, water is passed between the anion exchange membrane and the cation exchange membrane, and a non-aqueous electrolyte is passed between the cation exchange membrane and the negative electrode, A predetermined volume of empty space, ie, a channel, is formed between the upper housing and the lower housing, between the negative electrode and the anion exchange membrane, between the anion exchange membrane and the cation exchange membrane, and between the cation exchange membrane and the negative electrode. In this case, the channel between the positive electrode and the anion exchange membrane may be filled with not only the zinc chloride aqueous solution but also any solution that does not react with zinc and exhibits conductivity. In addition, a solution inlet for introducing a solution to be supplied to the channels is formed in the upper housing, and a solution outlet for discharging a solution discharged through the channels is formed in the lower housing.

Production Example 5. Preparation of water treatment device

A water treatment device was manufactured in the same manner as in Preparation Example 4, but unlike in Preparation Example 4, a water treatment device was manufactured using a PA doped PBI membrane as a cation exchange membrane.

Specifically, the PA doped PBI membrane was prepared by immersing PBI FuMA-Tech's Fumapem AM-40 with a thickness of 50 μm in 0.5M phosphoric acid for 24 hours. Such a cation exchange membrane can also be manufactured by spraying PBI on a conventional cation exchange membrane through a spray, but is not limited to these methods.

Experimental Example 3

In order to measure the performance of the water treatment device prepared in Preparation Example 4, a _{mixture of 10 mM ZnCl 2} aqueous solution, 10 mM NaCl aqueous solution and a fluorescent material (Alexa488, Invitrogen) through three solution inlets formed in the upper housing of the water treatment device, respectively, Then, a mixture of propylene carbonate solution and 0.1M NaPF ₆ aqueous solution is injected at a flow rate of 10 μl/min. At this time, a voltage of 0-100 V (Keithley 2461, Keithley Instrument) is applied to the carbon electrode of the device, and the solutions are continuously injected into the solution inlet using a hydraulic pump (Fusion 200, Revodix), At the same time, it allows the treated water to be discharged through the solution outlet.

In order to prevent consumption of the zinc thin film used as the anode during the water treatment process, _{zinc particles of 10 μm in size are dispersed in 10 mM ZnCl 2} aqueous solution, and then injected at a flow rate of 10 μl/min. Through this, it is possible to continuously supply zinc by using zinc particles as a flow electrode, and it is also possible to increase the capacity of the water treatment device by stacking two or more bipolar electrodes (BPE) as a unit cell.

9 and 10 schematically show the water treatment apparatus according to Preparation Examples 4 and 5, the desalination process using the same, and the formation and discharge process of a new compound generated in this process, respectively.

In addition, as described above, a water treatment device including a multi-layer structure in which two or more unit cells are stacked with bipolar electrodes and an operation method thereof are schematically shown in FIG. 11 . 11 schematically shows a process of desalting by supplying zinc particles between a bipolar layer (BPE) and an anion exchange membrane (AEM), and generating and separating a new compound.

The reaction equation of the irreversible electrochemical reaction occurring at the anode and the cathode in the water treatment device according to this experimental example can be expressed as follows:

_{In addition, sodium hydride (NaH) and zinc chloride (ZnCl 2} ) generated in the channels between the ion depletion layer between the cation exchange membrane and the anion exchange membrane of the water treatment device, between the anode and the anion exchange membrane, and between the cathode and the cation exchange membrane, or Other products can be observed through an inverted microscope (IX-73, Olympus) and an EMCCD camera (Image X2, Hamamatsu).

Experimental Example 4

By flowing a metal compound aqueous solution or metal slurry between the bipolar layer and the ion exchange membrane, ions separated from water and the metal compound can be synthesized into a new type of compound through an irreversible electrochemical reaction. In this case, depending on the particular compound, the chemical energy released while generating the compound may be used to obtain the additional benefit of reducing the driving voltage. For example, if a solution containing zinc (Zn) slurry is flowed into the layer in contact with the positively charged part of the bipolar electrode that does not participate in the reaction, Cl ^- ions flow into the layer in contact with the positively charged side Through the reaction with the zinc slurry, it loses electrons and undergoes an oxidation reaction to generate _{zinc chloride (ZnCl 2 ). Similarly, if sodium triiodide (NaI 3} ) aqueous solution is flowed into the layer in contact with the negatively charged part ^{, at this time, when Na +} ions are introduced, I ₃ ^- ions receive electrons from the bipolar electrode to form sodium iodide (NaI). can In this case, a metal iodine slurry may be used instead of sodium triiodide. In addition, this series of reactions has a redox potential of about 1.4 V, which serves to lower the driving voltage.

It coincides with the example of using an aluminum bipolar electrode in that the electrochemical method is applied and salt removal and synthesis are performed at the same time, but the compound is in an aqueous solution state, so it is easy to recover. In addition, by recovering these compounds (NaI, ZnCl ₂ ) It is also possible to take economic benefits.

Specifically, through three solution inlets formed in the upper housing of the water treatment device as in Preparation Example 4, a 10mM ZnCl ₂ aqueous solution, 10mM NaCl aqueous solution, and a fluorescent material (Alexa488, Invitrogen) each containing a zinc slurry of 10 μm in size. , and sodium triiodide (NaI ₃ ) aqueous solution is injected at a flow rate of 10 μl/min. At this time, a voltage of 0 to 6 V (Keithley 2461, Keithley Instrument) is applied to the carbon electrode of the device, and the solutions are continuously injected into the solution inlet using a hydraulic pump (Fusion 200, Revodix), At the same time, it allows the treated water to be discharged through the solution outlet. Fig. 12 schematically shows the water treatment device and a water treatment process through the water treatment device.

_{In addition, sodium hydride (NaH) and zinc chloride (ZnCl 2} ), or other products generated in the ion depletion layer between the cation exchange membrane and the anion exchange membrane of the water treatment device, and channels on each side of the anode and the cathode, were analyzed under an inverted microscope ( IX-73, Olympus) and EMCCD camera (Image X2, Hamamatsu) can be observed.

The ion depletion layer around the membrane-carbon conjugate of the water treatment device was observed through an upright microscope (Axio Zoom V16, Zeiss) and an EMCCD camera (Axiocam 506 ccolor, Zeiss), and the results are shown in FIG. 13 .

As shown in the right photo of FIG. 13 , as a result of checking the real-time desalting performance, it can be confirmed that the ion depletion layer appears black around the membrane-carbon conjugate in the water passing through the water treatment device. In addition, it was confirmed through the current-voltage graph of FIG. 14 that the driving voltage was lowered when having the same amount of ion flow (current) compared to the existing system.

Preparation Example 6. Preparation of water treatment device

A water treatment device was prepared similarly to Preparation Example 4. That is, a zinc thin film having a thickness of 230 μm and a graphite foil having a thickness of 370 μm are equally engraved to have a width of 0.5 mm and a length of 20 mm to form an anode and a cathode, respectively. In this case, the negative electrode is not limited to the graphite foil and may be replaced with a comprehensive electrode.

Next, as a cation exchange membrane, unlike Preparation Example 4, ASTOM's Neosepta CMX of 1 mm thickness was used, and ASTOM's Neosepta AMX was carved into a width of 0.5 mm and a length of 20 mm as an anion exchange membrane.

Next, the carved cation exchange membrane, the anion exchange membrane, the positive electrode, and the negative electrode are respectively inserted at a predetermined distance and at the same depth to be fixed and arranged in parallel with four grooves formed of a transparent polydimethylsiloxane (PDMS) material. The lower housing and the upper housing made of transparent polydimethylsiloxane (PDMS) material manufactured in the same shape and formed so that the cation exchange membrane, the anion exchange membrane, and the opposite ends of the anode and the cathode can be inserted and fixed at the same depth are chemically treated with 30 μL of silane It is coated through a chemical vapor deposition (CVD) process.

The carved positive electrode and the negative electrode are fitted into grooves formed at both ends of the lower housing, and the carved anion exchange membrane is fixed by fitting the carved anion exchange membrane into the groove formed at a distance of 1 mm from the positive electrode, and a groove formed at a distance of 1 mm from the negative electrode. Insert the fragmented cation exchange membrane to fix. At this time, the cation exchange membrane and the anion exchange membrane are positioned between the anode and the cathode, and the distance between the two exchange membranes is about 1 mm. After covering and fixing the upper housing made of a transparent polydimethylsiloxane (PDMS) material manufactured in the same form and formed so that the opposite ends of the anode, the cathode, the cation exchange membrane, and the anion exchange membrane can be fixed by being inserted to the same depth, plasma treatment A water treatment device is manufactured by joining the upper and lower housings through the

Preparation 7

A water treatment device was prepared similarly to Preparation Example 6, but both the positive electrode and the negative electrode were prepared in the form of a mesh. The anode and the cathode prepared in this way in the form of a mesh were respectively bonded to the anion exchange membrane and the cation exchange membrane as in Preparation Example 6.

Thereafter, the sculpted cation exchange membrane and the negative electrode assembly and the anion exchange membrane and positive electrode assembly are fixed and arranged in parallel by inserting them at a predetermined distance from both ends, and also at a predetermined distance between the two conjugates at the same depth. It is fixed by inserting it into the lower housing made of transparent polydimethylsiloxane (PDMS) material with two grooves to make it possible.

Thereafter, a transparent polydimethylsiloxane (PDMS) manufactured in the same shape as the lower housing and formed so that the opposite ends of the cation exchange membrane and the negative electrode assembly and the anion exchange membrane and the positive electrode assembly can be fixed by being inserted to the same depth. The upper housing of the material is coated with 30 μL of silane through a chemical vapor deposition (CVD) process.

The opposite ends of the cation exchange membrane and the negative electrode assembly fixed to the lower housing, and the anion exchange membrane and positive electrode assembly, respectively, are inserted into the two grooves formed in the upper housing to be fixed. In this case, the two conjugates are arranged in such a way that the cation exchange membrane and the anion exchange membrane face each other, and the anode and the cathode in the form of a mesh are positioned behind the anion exchange membrane and the cation exchange membrane, respectively, and they are each about from the end of the polydimethylsiloxane housing. They are positioned 1 mm apart. Accordingly, a water treatment device in which a channel is formed between the anode and the housing and between the cathode and the housing is manufactured.

Experimental example 5

In order to measure the performance of the water treatment device prepared in Preparation Example 6 and Preparation Example 7, _{a mixture of propylene carbonate solution and 0.1M NaPF 6} aqueous solution, 10 mM NaCl aqueous solution and A mixed solution of a fluorescent material (Alexa488, Invitrogen) and a mixture of propylene carbonate solution and 0.1M NaPF ₆ aqueous solution were injected at a flow rate of 10 μl/min.

The propylene carbonate solution may be replaced with any other solution as long as _{NaOH, ZnCl 2,} or other compounds that can be generated in these water treatment devices do not dissolve. The 0.1M NaPF ₆ aqueous solution is for making the mixed solution conductive, and _{instead of NaPF 6} NaOH, ZnCl ₂ , or any other material that does not react with other compounds that can be generated in these water treatment devices and does not affect the experiment. can be replaced.

A voltage of 0-100 V (Keithley 2461, Keithley Instrument) was applied to the carbon electrode of the device, and the solutions were continuously injected into the solution inlet using a hydraulic pump (Fusion 200, Revodix), and at the same time the solution outlet to allow the treated water to be discharged through the

In order to prevent consumption of the zinc electrode used as the anode during the water treatment process, _{zinc particles having a size of 10 μm are dispersed in a 10 mM ZnCl 2} aqueous solution, and then injected at a flow rate of 10 μl/min. Through this, it is possible to continuously supply zinc by using zinc particles as a flow electrode.

In the same principle as in Preparation Example 6 and Preparation Example 7, by stacking two or more bipolar electrodes (BPE) as a unit cell, it is possible to increase the capacity of the water treatment device.

15 and 17 are views schematically showing a water treatment method using the water treatment apparatus according to Preparation Example 6 and Preparation Example 7. In addition, in the water treatment apparatus according to Preparation Example 6, cations introduced through the cation exchange membrane are synthesized and formed as a new inorganic compound in the channel formed between the negative electrode and the cation exchange membrane in FIG. 16 . As can be seen from FIG. 16 , it can be seen that by injecting the organic solvent into the channel formed between the ion exchange membrane and the electrode, a new compound insoluble in the organic solvent can be directly generated in a solid state. These products can be discharged to the outside through this channel. It can be seen that, through this method, a new compound having a high added value can be easily prepared without the formation of concentrated water.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the appended claims It also falls within the scope of the present invention.

10: negative electrode, 20: positive electrode
10a, 20a: channel
30a: bipolar layer
10b, 30b: cation exchange membrane
20b, 30c: anion exchange membrane
40: Euro
50: housing
100, 200, 300: water treatment device

Claims (20)

anode;
a negative electrode disposed to face the positive electrode at a distance; and
one or more electrochemical units spaced apart from the positive electrode and the negative electrode, respectively;
The electrochemical unit is a water treatment device comprising a layer having a bipolar (bipolar) when a voltage is applied between the anode and the cathode. According to claim 1, wherein the layer having the bipolar (bipolar) is a water treatment device comprising an inorganic compound, an organic compound, a mixture of an inorganic compound and an organic compound, a complex of an inorganic compound and an organic compound, or a combination thereof. The water treatment device of claim 2, wherein the inorganic compound includes a metal. The water treatment apparatus of claim 3, wherein the metal includes a transition metal, a post-transition metal, a metalloid, or a combination thereof. The water treatment device of claim 2, wherein the organic compound includes carbon, a conductive polymer, or a combination thereof. According to claim 1, wherein the at least one electrochemical unit further comprises a cation exchange membrane, and/or an anion exchange membrane respectively disposed on one or both sides facing the anode and/or cathode of the layer of the bipolar layer water treatment device. The method of claim 6, wherein the cation exchange membrane is polystyrene, polyimide, polyester, polyether, polyethylene, polytetrafluoroethylene, polymethylammonium chloride (polymethylammonium chloride), polyglycidyl methacrylate, or an organic film containing a combination thereof, a NASICON ceramic film, or a phosphoric acid doped PBI film (PA doped polybenzimidazole membrane) water treatment device comprising a. The water treatment device of claim 1 , wherein the layer having the bipolarity has a plate type, a mesh type, a compressed form of particles, a solution containing particles, or a combination thereof. The water treatment device of claim 1, wherein the water treatment device includes two or more of the electrochemical units disposed between the anode and the cathode at a distance from each other. The apparatus of claim 1 , wherein the water treatment device comprises the positive electrode and the negative electrode and one or more electrochemical units therein, and a space between the positive electrode and the one or more electrochemical units and between the negative electrode and the one or more electrochemical units. The water treatment apparatus further comprising a housing having a water inlet for supplying water to the space of the , and a water outlet for discharging water discharged from the space. While applying a voltage between the positive electrode and the negative electrode of the water treatment device according to claim 1, water containing salt is supplied to the space between the positive electrode and the electrochemical unit and between the negative electrode and the electrochemical unit, and from the salt The separated cations and anions move to the cathode and anode in the water treatment device, respectively, and to a layer having a bipolarity in the electrochemical unit, and the supplied water is desalted. 12. The method of claim 11, wherein at least one of both surfaces of the bipolar layer, and/or at least one of the surfaces facing the bipolar layer of the anode and the cathode, is a cation exchange membrane disposed on the surface, An anion exchange membrane, or a water treatment method further comprising a combination thereof. The method of claim 11, wherein the voltage applied between the anode and the cathode is 0.1 V to 1,000 V. 12. The method of claim 11, wherein the positive and/or negative cations and/or anions migrated to the bipolar layer of the anode and the cathode and the electrochemical unit are adsorbed to at least one of the bipolar layer and/or the anode and the cathode water treatment method. 12. The method of claim 11, wherein the positive and negative cations and/or anions migrated to the layer having the bipolarity of the positive electrode and the negative electrode, and the electrochemical unit having the bipolarity of at least one of the negative electrode and the positive electrode A water treatment method with an irreversible electrochemical reaction with the bed. The method of claim 11 , wherein the water treatment method does not produce concentrated water. The method of claim 11, wherein the layer having the bipolarity is in the form of a solution containing particles. The method of claim 7, wherein the solution containing the particles is a solution containing zinc particles. Supplying water containing salt to the space between the positive electrode and the negative electrode while applying a voltage between the positive electrode and the negative electrode disposed to face each other at a predetermined interval,
The cation separated from the salt in the water moves to the negative electrode, and the anion separated from the salt in the water moves to the positive electrode, so that the migrated cation and/or anion are irreversible with the negative electrode and/or the positive electrode, respectively. A water treatment method comprising causing a chemical reaction and desalting the supplied water. The method of claim 19, wherein an anion exchange membrane is disposed on one surface of the positive electrode, and a cation exchange membrane is disposed on one surface of the negative electrode.

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