KR20150035265A - Capacitive deionization electrodes and production methods thereof, and capacitive deionization apparatus including the same - Google Patents

Abstract

In the present invention, provided are an electro-adsorption deionization electrode, which includes a carbon material; and a fine particle of 5 parts by weight of hydrophilic metal oxide for 100 parts by weight of the carbon material, a manufacturing method thereof and an electro-adsorption deionization device including the same. For this, the electro-adsorption deionization electrode comprises a fine particle of 4 parts by weight of hydrophilic metal oxide for 100 parts by weight of the carbon material.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition-type deionization electrode, a production method thereof, and an electrodeposition-

To an electrodeposition-type deionization electrode, a production method thereof, and an electrodeposition deionization apparatus containing the same.

Depending on the region, domestic water may also contain high levels of minerals. In particular, the mineral content in tap water is high in Europe where limestone components are mainly introduced as groundwater. When water having a high mineral content (i.e., hard water) is used in a domestic facility, such as a heat exchanger or a boiler, there is a problem in that scale is generated on the inner wall of the pipe and energy efficiency is greatly reduced. Also, the hard water is not suitable for use as a washing water. For this reason, there is a demand for a technique capable of removing ions from a light water reactor, in particular, environmentally friendly to make soft water. On the other hand, along with the recent increase in water scarcity area, demand for seawater desalination technology is increasing.

In the electrochemical deionization (CDI) apparatus, a voltage is applied to an electrode including nano-sized pores, and the electrode is polarized, thereby adsorbing the ionic substance from the medium such as hard water or seawater to the surface of the electrode It is a device to remove. In the CDI apparatus, when a DC power source having a low potential difference is applied while allowing a medium containing dissolved ions to flow between the two electrodes of the positive and negative electrodes, the anion component is adsorbed on the positive electrode and the positive ion component is adsorbed on the negative electrode. Meanwhile, when a reverse current flows between the two electrodes by shorting the two electrodes, the concentrated ions are separated from the electrodes. Since the CDI device does not require a high potential difference, it has high energy efficiency and can remove harmful ions together with the hardness component in the ion adsorption, and no chemicals are required during regeneration.

One embodiment relates to an electrodeposition-type deionization electrode exhibiting a high adsorption capacity and an improved deionization efficiency.

Another embodiment relates to a method of manufacturing the above-described electrodeposition-type deionized electrode.

Another embodiment is directed to an electrodeposition deionization device comprising the electrodeposition deionized electrode.

In one embodiment, the electrospinning deionization electrode comprises a carbon material; And 5 parts by weight or less of hydrophilic metal oxide particles per 100 parts by weight of the carbon material.

The electrospinning deionization electrode may include fine particles of a hydrophilic metal oxide of 4 parts by weight or less per 100 parts by weight of the carbon material.

The electrode may further include a binder, and the amount of the hydrophilic metal oxide may be 5 wt% or less based on the total content of the carbon material, the hydrophilic metal oxide fine particles, and the binder.

The carbon material may be at least one selected from activated carbon, carbon nanotubes, activated carbon fibers, carbon nanofibers, carbon aerogels, mesoporous carbon, and graphite oxides.

Wherein the carbon material is activated carbon and the activated carbon has an aluminum (Al) content of 2 to 35%, a silicon (Si) content of 3 to 25 wt% and an oxygen (O) content based on the total weight of components excluding carbon ) Content may be 20 to 50 wt%, the specific surface area may be 1000 m ² / g or more, and the average pore diameter may be 2 to 5 nm.

The hydrophilic metal oxide may be SiO ₂ , TiO ₂ , Al ₂ O ₃ , BaTiO ₃ , or a combination thereof.

The fine particles of the hydrophilic metal oxide may have an average particle diameter of 70 nm or less.

The hydrophilic metal oxide may be colloidal silica, silica powder, silica gel powder, colloidal titania, or a combination thereof.

The binder may comprise a cation exchanger or an anion exchanger and is selected from the group consisting of polyacrylic acid, poly (acrylic acid-maleic acid) copolymer, polyvinyl alcohol, cellulose, polyvinylamine, chitosan, polyacrylamide, poly ) Copolymer or a poly (styrene-acrylic acid) copolymer, or at least one hydrophilic polymer selected from the group consisting of polystyrene, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyamide, polyvinylpyrrolidone , Polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resins, and mixtures thereof.

The cation exchanger includes a sulfonic acid group (-SO ₃ H), a carboxyl group (-COOH), a phosphonic group (-PO ₃ H ₂ ), a phosphonic group (-HPO ₃ H), an acid group (-AsO ₃ H ₂ (-NH ₃ ), primary amine (-NH ₂ ), secondary amine (-NHR), and 3-aminocarbonyl group (-SeO ₃ H) (-NR ₂ ), a quaternary phosphonium group (-PR ₄ ), and a tertiary sulfonium group (-SR ₃ ).

The electrode may further include a conductive additive, a polyfunctional compound having at least one functional group reactive with a hydrophilic functional group, or both.

In another embodiment, a method of making an electrodeposition-deionized electrode comprises: a carbon material; Fine particles of a hydrophilic metal oxide of 5 parts by weight or less per 100 parts by weight of the carbon material; bookbinder; And a solvent; And applying the slurry onto a conductive support and removing the solvent to form an electrode layer.

The carbon material may be at least one selected from activated carbon, carbon nanotubes, activated carbon fibers, carbon nanofibers, carbon aerogels, mesoporous carbon, and graphite oxides.

The hydrophilic metal oxide may be SiO ₂ , TiO ₂ , Al ₂ O ₃ , BaTiO ₃ , or a combination thereof.

The fine particles of the hydrophilic metal oxide may have an average particle diameter of 70 nm or less.

The slurry may further contain a conductive additive, a polyfunctional compound having at least one functional group reactive with a hydrophilic functional group, or both.

The method may further include the step of cross-linking the binder by heat treating the electrode layer at a temperature of 130 ° C or higher, wherein the slurry contains the polyfunctional compound.

In another embodiment, the electrodeposition deionization apparatus comprises a carbon material; And 5 parts by weight or less of hydrophilic metal oxide particles per 100 parts by weight of the carbon material.

The electrodeposition-type deionized electrode has a high ion-adsorbing ability and has an improved water-treating ability and can provide a large amount of high-purity water in a short time.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a schematic structure of an electrodeposition deionization apparatus according to one embodiment. Fig.
2 is a graph showing the deionization performance of the electrode of Comparative Example 1 (without conductive auxiliary agent) and the electrode of Comparative Example 2 (including conductive auxiliary agent).
3 is a graph showing the deionization performance of the electrode of Comparative Example 1 and the electrode of Example 2. Fig.
FIG. 4 shows changes in the lowest ionic conductivity and the last ionic conductivity measured in the adsorption step according to the content of SiO ₂ .
FIG. 5 is a diagram showing the change of the required time and the holding time according to the content of SiO ₂ .
FIG. 6 is a graph showing changes in the lowest ionic conductivity and the last ionic conductivity measured in the adsorption step, according to the SiO ₂ particle size. FIG.
FIG. 7 is a graph showing the change of the required time and the holding time according to the SiO ₂ particle size. FIG.
8 is a graph showing the resistivity of the electrodes of Examples 1 to 5 and the electrode of Comparative Example 1. Fig.
9 is a diagram showing a water uptake of the electrodes of Examples 1 to 5 and the electrode of Comparative Example 1. Fig.
10 is a graph showing the results of SEM-EDS analysis of the cross section of the electrode of Example 3. Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Thus, in some implementations, well-known techniques are not specifically described to avoid an undesirable interpretation of the present invention. Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs. Also, commonly used predefined terms are not ideally or excessively interpreted unless explicitly defined otherwise. Whenever a component is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements, not the exclusion of any other element, unless the context clearly dictates otherwise.

Also, singular forms include plural forms unless the context clearly dictates otherwise.

Embodiments described herein will be described with reference to schematic diagrams which are ideal illustrations of the present invention. Thus, the regions illustrated in the figures have schematic attributes and are not intended to limit the scope of the invention. Like reference numerals refer to like elements throughout the specification.

In the present specification, the term " electrodeposition deionization device "refers to a device for passing a separation-target fluid or a concentration-target fluid containing at least one ion component through a flow path formed between at least a pair of deionization electrodes Refers to a device capable of adsorbing and separating / concentrating the ion components to pores contained in the electrode by applying a voltage. The "electrodeposition deionization device" may have any geometric shape.

In one embodiment, the electrospinning deionization electrode comprises a carbon material; And 5 parts by weight or less, for example, about 4 parts by weight or less, of hydrophilic metal oxide per 100 parts by weight of the carbon material.

The carbon material may be at least one selected from activated carbon, carbon nanotubes, activated carbon fibers, carbon nanofibers, carbon aerogels, mesoporous carbon (for example, ordered mesoporous carbon), and graphite oxides. For example, the carbon material may be activated carbon. Activated carbon is an amorphous carbon aggregate that is produced from various sources such as coconut shells and coal, and has well-developed micropores. Activated carbon contains pores of different sizes, has a high specific surface area of, for example, 900 m ² / g or more, and is useful as an electrode material because of its small electric resistance. When the carbon material is activated carbon, the activated carbon preferably has an aluminum (Al) content of 2-35 wt%, for example, 5 to 30 wt% based on the total weight of components excluding carbon, The content may be 3-25 wt%, for example, 7-20 wt%. The activated carbon may have a specific surface area of 900 m ² / g or more, for example, 1,000 m ² / g or more, and an average pore diameter of 2 to 5 nm.

The hydrophilic metal oxide may be SiO ₂ , TiO ₂ , Al ₂ O ₃ , BaTiO ₃ , or a combination thereof. The fine particles of the hydrophilic metal oxide may have an average particle size of 70 nm or less, such as 60 nm or less, 50 nm or less, 40 nm or less, 30 nm or less, and 20 nm or less. When the hydrophilic metal oxide having such an average particle diameter is included, the treated water passing between the deionized electrodes can exhibit a low ion conductivity in a short time, and such a low ion conductivity can be maintained for a longer time. The hydrophilic metal oxide may be colloidal silica, silica powder, silica gel powder, colloidal titania, or a combination thereof.

The carbon material may have a number of pores of the same or different size (s), and is useful, for example, as an electrode material for an electrodeposition deionization device having a high specific surface area and a low electric resistance. However, the surface of these carbon materials tends to have hydrophobicity, so that they have a large adsorption capacity, but they have a limited area in which they can directly come into contact with treated water and the like, and it may take a long time until the contact occurs. For this reason, it is difficult for many carbonaceous materials to efficiently utilize a large number of ion-adsorbing sites which they possess, and thus, exhibits a limited adsorption capacity. Therefore, it is inevitable to use a large-area electrode or a large amount of carbon material in order to treat, for example, a high-ion-concentration undiluted solution (for example, hard water or seawater) at a high speed.

In contrast, the deionized electrode according to the above-described embodiment includes the carbon material and the hydrophilic metal oxide, so that the treated water can easily penetrate into the carbon, thereby significantly increasing the adsorption rate and providing more adsorption sites So that more ions can be adsorbed and removed even by using a small amount of carbon material.

The electrode may further include a binder. Since the deionized electrode is placed under repeated charge and discharge, the mechanical strength of the electrode tends to deteriorate, and the life of the electrode may be reduced due to the release of the carbon material. In order to prevent this, the binder serves to fix the carbon material to the electrode, thereby improving the physical properties of the electrode. In other words, the binder may further comprise a binder that allows the carbon material to be connected to each other to form a continuous structure and to allow each electrode to adhere well to the current collector. In this case, the amount of the hydrophilic metal oxide may be 5 wt% or less, for example, 0.01 to 5 wt%, or 0.1 to 3 wt% based on the total content of the carbon material, the hydrophilic metal oxide fine particles, and the binder. The content of the carbon material may be 50 to 90% by weight. The content of the binder may be 9 to 45% by weight.

Wherein the binder is selected from the group consisting of polyacrylic acid, poly (acrylic acid-maleic acid) copolymer, polyvinyl alcohol, cellulose, polyvinylamine, chitosan, polyacrylamide, poly (acrylamide- And at least one hydrophilic polymer selected from a copolymer. Alternatively, the binder may be selected from the group consisting of polystyrene, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyamide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride , A polymer selected from polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resins, and mixtures thereof. The binder may include a cation exchanger or an anion exchanger. The cation exchanger includes a sulfonic acid group (-SO ₃ H), a carboxyl group (-COOH), a phosphonic group (-PO ₃ H ₂ ), a phosphonic group (-HPO ₃ H), an acid group (-AsO ₃ H ₂ ), And a selinolytic group (-SeO ₃ H). The anion exchanger is a quaternary ammonium (-NH _3), 1 primary amine (-NH _{2), 2} amine (-NHR), 3 tertiary amine group (-NR _2), quaternary phosphonium nyumgi (-PR ₄ ), And a tertiary sulfonium group (-SR ₃ ).

The electrode may further include at least one of a conductive additive and / or a polyfunctional compound having at least one functional group capable of reacting with a hydrophilic functional group (e.g., a hydrophilic polymer).

The conductive additive can enhance the conductivity of the electrode. The kind of the conductive auxiliary agent is not particularly limited, and materials used for ordinary electrode production can be used. As a non-limiting example, the conductive additive may be a carbon-based material such as carbon black, Vapor Growth Carbon Fiber (VGCF), natural graphite, artificial graphite, acetylene black, Ketjenblack or carbon fiber; Metal powders such as copper, nickel, aluminum, and silver, or metal-based materials such as metal fibers; Conductive polymers such as polyphenylene derivatives, and mixtures thereof.

The polyfunctional compound may play a role of forming a cross-link between polymer chains as a binder. The polyfunctional compound may be a compound having two or more carboxylic acid groups, a compound having two or more hydroxyl groups, a compound having two or more amine groups, or a compound having two or more epoxy groups. The polyfunctional compound may be at least one selected from the group consisting of a sulfonic acid group, a carboxylic acid group, a phosphonic group (-PO ₃ H ₂ ), a phosphonic group (-HPO ₂ H), an acidic group (-AsO ₃ H ₂ ) ₃ H), and the like. Alternatively, the polyfunctional compound may have an ammonium salt group, a primary to tertiary amine group, a quaternary phosphonium group (PR ₄ ), and a tertiary sulfonium group (SR ₃ ). Examples of such compounds include, but are not limited to, sulfosuccinic acid and sulfosalicylic acid.

In another embodiment, a method of making an electrodeposition-deionized electrode comprises: a carbon material; Fine particles of a hydrophilic metal oxide of 5 parts by weight or less per 100 parts by weight of the carbon material; bookbinder; And a solvent; And applying the slurry onto a conductive support and removing the solvent to form an electrode layer.

The step of obtaining the slurry includes a step of dissolving the binder in a solvent to obtain a binder solution; And adding a carbon material and a hydrophilic metal oxide to the binder solution. The method may further include heating the applied electrode layer on the support to perform crosslinking between the binder and the polyfunctional compound.

The solvent removal (drying) may be at a temperature of 70 degrees Celsius or more, such as 100 degrees Celsius to 200 degrees Celsius, 120 degrees Celsius to 150 degrees Celsius, but is not limited thereto. The time for removing the solvent may be 10 minutes or more, for example, 30 minutes to 2 hours, but is not limited thereto. The heating of the electrode layer for the binder crosslinking may be performed at a temperature of 100 DEG C or more, for example, 120 to 150 DEG C for 20 minutes or more, for example, 30 minutes to 2 hours, but is not limited thereto. Solvent removal and electrode layer heating may be performed simultaneously.

The content of the carbon material, the hydrophilic metal oxide fine particles, and the binder is as described above. The kind of the solvent contained in the slurry is not particularly limited and may be appropriately selected. For example, the solvent is not particularly limited, but a solvent capable of dissolving the binder may be used. Examples of the solvent include water, diphenylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, acetone, chloroform, dichloromethane, trichlorethylene, ethanol, methanol, n-hexane, But is not limited thereto. Mixtures of two or more solvents may also be used.

The slurry may further include at least one of a conductive auxiliary agent, a crosslinking agent, and a polyfunctional compound having at least one functional group reactive with a hydrophilic functional group. Specific details of the conductive auxiliary agent, crosslinking agent and polyfunctional compound are as described above.

The thickness of the electrode layer is not particularly limited and may be appropriately selected. For example, the thickness of the electrode layer may be in the range of about 50 탆 to 500 탆, specifically about 100 탆 to 300 탆. The conductive support may be a current collector. In the case where the electrodeposition deionization apparatus described later includes a plurality of electrode pairs, electrodes may be coupled to both sides of the current collector. The current collector is electrically connected to a power source to apply a voltage to the electrode. The current collector may be a graphite plate or a graphite foil or may comprise at least one metal, metal mixture or alloy selected from the group consisting of Cu, Al, Ni, Fe, Co, and Ti. The current collector may be in the form of a sheet, a foam or a mesh, but is not limited thereto.

In another embodiment, the electrodeposition deionization apparatus comprises a carbon material; And 5 parts by weight or less of hydrophilic metal oxide particles per 100 parts by weight of the carbon material.

Carbon material, fine particles of hydrophilic metal oxide, and electrodeposition-deionized electrode are as described above. The electrodeposition deionization device may be formed into any geometrical structure. By way of non-limiting example, the electrodeposition deionization device may have a schematic structure as shown in Figs. 1 (A) to 1 (C), but is not limited thereto, and may be any known or commercially available structure Lt; / RTI > Hereinafter, the above-described electrodeposition-deionizing apparatus will be described with reference to these drawings. 1 (A), the electrodes 2, 2 'are applied to the current collector 1, and the spacer structure 3 is inserted between the electrodes 2, 2' . In the case of the electrodeposition deionization apparatus shown in Fig. 1 (B), the current collector 1 is coated with electrodes 2 and 2 ', and the spacer structure 3 is formed between the electrodes 2, Is inserted to form a channel, wherein a cation-selective permeable membrane (4 or 4 ') and an anion-selective permeable membrane (4' or 4) are inserted between the electrode and the spacer structure. 1 (C), the current collector 1 is coated with electrodes 2, 2 ', and the spacer structure 3 is inserted between the electrodes 2, 2' (Or a cathode) using an anion (or cation) exchangeable binder and the electrode 2 'is a cathode (or an anode) using a cation (or anion) exchangeable binder .

The electrodeposition deionization device may further comprise a charge barrier disposed between the spacer structure and the porous electrode. The charge barrier may be a cation-selective permeable membrane or an anion-selective permeable membrane. The cationic or anionic selective permeable membrane may be prepared by a suitable method or a commercially available product may be used. Specific examples of the cationic or anion-selective permeable membrane that can be used in the above-described electroabsorption deionization device include Neosepta CMX or Neosepta AMX manufactured by Tokuyama Co., But is not limited thereto.

The above-described electrodeposition-type deionization electrode can be found not only in an electrodeposition deionization apparatus but also in electronic devices such as a capacitor, a secondary battery, and a fuel cell.

The electrodeposition deionization apparatus including the above-described electrodeposition-type deionization electrode may be a deionization process for removing ultra-pure water, a water purification process for removing salt (for example, desalination of seawater), a calcium ion removal process It can be applied to a wide range of fields such as used beverage manufacturing process, domestic appliances (washing machine, dishwasher, steam cleaner, refrigerator, water purifier, coffee maker), boiler for removing ions in distilled water and industrial water production process.

Hereinafter, specific embodiments of the present invention will be described. It should be noted, however, that the embodiments described below are only intended to illustrate or explain the invention in detail, and thus the present invention should not be limited thereto.

[ Example ]

Examples 1 to 6 and Comparative Examples 1 to 4 : Preparation of CDI Electrode

Al content = 30 wt%, Si content = 8 wt%, and O content = 10 wt% in the components other than carbon (SPY, manufactured by Samchully Carbotech Co., (SSAA), colloidal silica (Ludox, Aldrich, 40 wt.% Si / SiO2), and the average pore diameter H ₂ O, 34 wt% Si / H ₂ O), silica powder (manufactured by Aldrich), KIT-6 (synthetic amorphous silica) and super P (manufactured by Timcal Graphite & Carbon) , Respectively, to prepare a slurry. The prepared slurry is coated on a graphite sheet with a doctor blade and dried at 130 ° C for 1 hour to prepare an electrode having an active material thickness of 150 to 250 μm.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 0% Si_w / conductive material 0% Si_w / o conductive material 1% Si powder 1% synthetic silica composite Si particle size (nm) NA ~ 100 ~ 500 mass (g) wt% mass (g) wt% mass (g) wt% mass (g) wt% 10 wt% PVA 12.6 26.8 12.6 29.6 12.6 26.8 12.6 26.8 40 wt% Si / H ₂ O 0.0 0.0 34 wt% Si / H ₂ O Si powder 0.05 1.1 KIT-6 (powder) 0.05 1.1 SsuA 0.774 0.774 0.774 0.774 SsaA 2.898 2.898 2.898 2.898 super P 0.45 9.6 SPY 3 63.7 3 70.4 3.4 72.2 3.4 72.2 total (g) 4.710 100.0 4.260 100.0 4.710 100.0 4.710 100.0 Solids (SC) / total (%) 23.88 22.10 23.88 23.88

Electro Adsorption Deionization Experiment I :

The electrodes prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were used as cathodes and the electrodes were made of PVA, GTMAc (glucidyl trimethylammonium chloride), glutaric acid, mixed slurry of SPY activated carbon 1C was manufactured using an electrode (active material thickness: 250 μm) as an anode and a polyamide mesh (manufacturer: SEFAR, thickness: 100 μm) as a spacer do. The water of 200 ppm mixed ion concentration was injected into the prepared electrodeposition deionizer at a flow rate of 28 cc / min. While charging at 1.5 V for 1 minute and discharging at -0.8 V for 5 minutes, charging / discharging was repeated do. The ionic conductivity of the effluent measured at the outlet of the apparatus is measured to observe the adsorption / desorption behavior of the ions. The results are shown in Fig. 2 to Fig.

2 compares the deionization performance of the electrode of Comparative Example 1 in which super P is added as a conductive auxiliary agent and the electrode of Comparative Example 2 in which there is no conductive auxiliary agent. According to the results shown in Fig. 2, it is confirmed that the addition of the conductive additive does not substantially affect the lowest ion concentration, and contributes little to the performance improvement.

3 compares the deionization performance of the electrode of Comparative Example 1 with that of the electrode of Example 2. Fig. 3, the electrode of Example 2 having hydrophilic metal oxide fine particles had a significantly lower minimum ion conductivity than that of the electrode of Comparative Example 1 and had a significantly lower ion conductivity than the electrode of Comparative Example 1 even after 1 minute of charging Confirm that it has conductivity value. That is, by the addition of colloidal SiO ₂ particles, fast adsorption behavior and a large increase in adsorption capacity are confirmed. Without wishing to be bound by any particular theory, this is believed to be due to the fact that the added hydrophilic metal oxide fine particles rapidly transfer the hard water to the inside of the electrode. These results suggest that the electrode of Example 2 has significantly improved deionization performance and efficiency as compared to the electrode of Comparative Example 1.

FIG. 4 is a graph showing the values of the lowest ionic conductivity and the final ionic conductivity measured in the adsorption step (charging state for 1 minute) according to the content of SiO ₂ . From FIG. 4, it is confirmed that the electrodes manufactured according to Examples 1, 2, 3, 4, and 5 have significantly lower ion conductivity and last ion conductivity than the electrodes of Comparative Example 1. Specifically, the lowest minimum ionic conductivity at 0.4 wt% SiO ₂ content was found, and the final ionic conductivity at the adsorption step (an indicator for evaluating deionization throughput) was also found to be 61 μS / cm.

5 shows the required time and holding time according to the content of SiO ₂ . Here, the term "required time" refers to the time required for the ion conductivity of the drain water that has passed through the electrode to reach 90 mu S / cm. Here, the term "holding time" refers to the time during which the discharged water retains the ionic conductivity of 90 μS / cm or less. (Running time) From FIG. 5, it was found that the electrodes manufactured according to Examples 1, 2, 3, 4, and 5 significantly reduced the time required and the holding time significantly compared to the electrode of Comparative Example 1 . On the other hand, when the SiO ₂ content is 0.4 wt%, the maximum water treatment capacity is confirmed. The time required to reach 90 μS / cm and the retention time are confirmed to be 5 seconds (45% decrease compared to Comparative Example 1) and 55 seconds (100% increase relative to Comparative Example 1), respectively.

FIG. 6 is a graph showing the values of the lowest ionic conductivity and the last ionic conductivity measured in the adsorption step, according to the SiO ₂ particle size. From FIG. 6, it is confirmed that the electrodes of Examples 3 and 6 have significantly lower ion conductivity and final ion conductivity than the electrodes prepared according to Comparative Examples 3 and 4. The SiO ₂ particles is made small to decrease the ion conductivity. This is considered to be because the surface area that can be adsorbed is increased and the adsorption capacity is increased. The SiO ₂ particle size may be 20 nm or less.

FIG. 7 shows the time required for the SiO ₂ particle size and the retention time. From FIG. 7, it can be seen that the electrodes prepared according to Example 3 and Example 6 exhibit a low level of time required and an increased retention time. The smaller the size of the SiO ₂ particles, the greater the amount of water treated. In the case of a certain particle size or more, the actual usable water treatment (<100 μS / cm, throughput rate 90%) may be out of the range.

Electrical conductivity and water of deionized electrode Evaluation of up-take :

For the electrodes of Examples 1 to 5 and the electrode of Comparative Example 1, the non-electric resistance and the amount of water uptake are measured in the following manner.

(1) Non-electrical resistance

A Teflon sheet is placed on the upper and lower surfaces of the electrode sample with an area of 3.36 cm ² , and pressed into a press at a pressure of 600 bar (2 metric tons). The thickness (t ₁ ) of the pressed sample is measured. The thickness (t ₂ ) of the current collector pressed at a pressure of 600 bar by the press is obtained, and the thickness of the active material layer pressed from t ₁ and t ₂ is obtained. A resistance (R ₁ ) of the compressed electrode sample and a resistance (R ₂ ) of only the current collector are obtained by using a multi-tester. The resistivity is calculated from the following formula.

(R ₁ -R ₂ ) × 3.36 cm ² / (t ₁ -t ₂ ) cm

(2) Water up take

An electrode sample with an area of 100 cm ² is dried at 50 ° C for 48 hours and the dry weight (W ₁ ) is measured. The dried electrode sample is immersed in deionized water for 1 hour, removed, and the water is removed from the surface. After drying in an oven at 50 ° C for 5 hours, the weight (W ₂ ) is measured. A water-up take is obtained from the following equation.

(W ₂ - W ₁ ) (g) / 100 (cm ² )

The results are shown in Fig. 8 and Fig. From the results of FIG. 8, it can be seen that the specific electrical resistances of the electrodes of Examples 1 to 5 are slightly larger than the specific electrical resistivity of the electrode of Comparative Example 1, and the electrical resistivity is larger as the SiO ₂ content is increased. However, from the results of FIG. 9, it can be seen that the electrodes of Examples 1 to 5 are much larger than those of Comparative Example 1 in the water-up take. Therefore, it is confirmed that the electrodes of Examples 1 to 5 can exhibit high efficiency as deionized electrodes, compared with the electrodes of the comparative example, despite the somewhat increased non-electrical resistance. Specifically, the specific electrical resistance of the electrode may be increased by 0.62 to 1.28 times, but the water-up take may be increased by 9.8 to 16.3 times depending on the content of SiO ₂ . It can be considered that the increase in the deionization amount (increase in the ion conductivity and the effective ion conductivity retention time) with the addition of SiO _{2 is} more affected by the increase of the water up take than the increase of the non-electrical resistance.

SEM - EDS analysis of fabricated deionized electrode cross - section :

(UHR-FE-SEM, model: Hitachi S-5500, resolution 0.4 nm, operating at 30 kV) and energy dispersive X-ray spectroscopy A cross section of the electrode of Example 3 was analyzed using a dispersive X-ray spectroscopy (EDAX) apparatus. The results are shown in FIG. From the results of FIG. 10, it can be seen that Si is unevenly distributed in the electrode cross section, and the Si particles are present at substantially the same position as Al existing as an impurity in the active material.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, And falls within the scope of the invention.

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2, 2 ': electrode
3: Spacer
4, 4 ': charge barrier

Claims (23)

Carbon material; And 5 parts by weight or less of hydrophilic metal oxide per 100 parts by weight of the carbon material. The method according to claim 1,
Wherein the electrode further comprises a binder and the amount of the hydrophilic metal oxide is 5 wt% or less based on the total content of the carbon material, the hydrophilic metal oxide fine particles, and the binder. The method according to claim 1,
Wherein the carbon material is at least one selected from the group consisting of activated carbon, carbon nanotubes, activated carbon fibers, carbon nanofibers, carbon aerogels, mesoporous carbon, and graphite oxides. The method according to claim 1,
The carbon material preferably has an aluminum (Al) content of 2 to 35%, a silicon (Si) content of 3 to 25% and a specific surface area of 1000 m ² / g or more based on the total weight of components excluding carbon , An activated carbon having an average pore diameter of 2 to 5 nm. The method according to claim 1,
Wherein the hydrophilic metal oxide is SiO ₂ , TiO ₂ , Al ₂ O ₃ , BaTiO ₃ , or a combination thereof. The method according to claim 1,
Wherein the fine particles of the hydrophilic metal oxide have an average particle size of 70 nm or less. The method according to claim 1,
Wherein the hydrophilic metal oxide comprises colloidal silica, silica powder, silica gel powder, colloidal titania or a combination thereof. The method according to claim 1,
The binder may comprise a cation exchanger or an anion exchanger and is selected from the group consisting of polyacrylic acid, poly (acrylic acid-maleic acid) copolymer, polyvinyl alcohol, cellulose, polyvinylamine, chitosan, polyacrylamide, poly ) Copolymer or a poly (styrene-acrylic acid) copolymer, or at least one hydrophilic polymer selected from the group consisting of polystyrene, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyamide, polyvinylpyrrolidone , A polymer selected from polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, electrode. 9. The method of claim 8,
The cation exchanger includes a sulfonic acid group (-SO ₃ H), a carboxyl group (-COOH), a phosphonic group (-PO ₃ H ₂ ), a phosphonic group (-HPO ₃ H), an acid group (-AsO ₃ H ₂ ) And a selinolytic group (-SeO ₃ H), and the anion exchanger is selected from the group consisting of a quaternary ammonium salt (-NH ₃ ), a primary amine (-NH ₂ ), a secondary amine (-NHR) An electrospinning deionization electrode selected from the group (-NR ₂ ), the quaternary phosphonium group (-PR ₄ ), and the tertiary sulfonium group (-SR ₃ ). The method according to claim 1,
A conductive auxiliary agent, and a polyfunctional compound having at least one functional group reactive with a hydrophilic functional group. Carbon material; Fine particles of a hydrophilic metal oxide of 5 parts by weight or less per 100 parts by weight of the carbon material; bookbinder; And a solvent; And
Applying the slurry to a conductive support, and removing the solvent. 12. The method of claim 11,
Wherein the carbon material is at least one selected from the group consisting of activated carbon, carbon nanotubes, activated carbon fibers, carbon nanofibers, carbon aerogels, mesoporous carbon, and graphite oxides. 12. The method of claim 11,
The carbon material preferably has an aluminum (Al) content of 2 to 35%, a silicon (Si) content of 3 to 25% and a specific surface area of 1000 m ² / g or more based on the total weight of components excluding carbon , And an activated carbon having an average pore diameter of 2 to 5 nm. 12. The method of claim 11,
Wherein the hydrophilic metal oxide is SiO ₂ , TiO ₂ , Al ₂ O ₃ , BaTiO ₃ , or a combination thereof. 12. The method of claim 11,
Wherein the fine particles of the hydrophilic metal oxide have an average particle size of 70 nm or less. 12. The method of claim 11,
Wherein the slurry further comprises at least one of a conductive auxiliary agent and a polyfunctional compound having at least one functional group reactive with a hydrophilic functional group. Carbon material; And an electrode comprising fine particles of a hydrophilic metal oxide of 5 parts by weight or less per 100 parts by weight of the carbon material. 18. The method of claim 17,
Wherein the electrode further comprises a binder and the amount of the hydrophilic metal oxide is 5% by weight or less based on the total content of the carbon material, the hydrophilic metal oxide fine particles, and the binder. 18. The method of claim 17,
Wherein the carbon material is at least one selected from activated carbon, carbon nanotubes, activated carbon fibers, carbon nanofibers, carbon aerogels, mesoporous carbon, and graphite oxides. 18. The method of claim 17,
The carbon material preferably has an aluminum (Al) content of 2 to 35%, a silicon (Si) content of 3 to 25% and a specific surface area of 1000 m ² / g or more based on the total weight of components excluding carbon , And an average pore diameter of 2 to 5 nm. 18. The method of claim 17,
The hydrophilic metal _{oxide, SiO 2, TiO 2, Al} 2 O 3, BaTiO 3, or the electrical deionization apparatus adsorption combinations thereof. 18. The method of claim 17,
Wherein the fine particles of the hydrophilic metal oxide have an average particle size of 70 nm or less. 18. The method of claim 17,
Wherein the hydrophilic metal oxide comprises colloidal silica, silica powder, silica gel powder, colloidal titania or a combination thereof.

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