KR100979028B1 - Separator Membrane for Capacitive Deionization of Waste Water or Saltwater, and Method for Deionization of Waste Water or Saltwater By Using the Separator Membrane - Google Patents

Abstract

The present invention is a separator for ion removal, consisting of a material selected from the group consisting of polycarbonate, Teflon, acrylic and polychlorotrifluoroethylene, the groove shape is dug to less than 1 ~ 2mm from both sides or one side Separator for capacitive deionization (CDI) of wastewater or brine, characterized in that it has a plurality of channels of, and comprises a source inlet connected to one side and an outlet connected to the other side, and the wastewater or brine using the separator An ion removal method is provided.

The separator of the present invention prevents electrical shorts by preventing the contact between the carbon anode and the carbon cathode during the CDI process, and has a uniform channel to facilitate the flow of the waste liquid to be treated, and sufficient separation between the waste liquid to be treated and the carbon anode and the cathode. It has the effect of causing reactivity.

Membrane, Ion Removal, Wastewater, Brine, Polycarbonate

Description

Separator Membrane for Capacitive Deionization of Waste Water or Saltwater, and Method for Deionization of Waste Water or Saltwater By Using the Separator Membrane

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram which shows the principle of an electrical storage deionization method.

2 is a detailed structural diagram of the separator of the present invention.

3 is a schematic diagram of a CDI apparatus using a separator according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

1 ..... cathode 2 ..... anode

3 ..... waste water or brine 4 ..... pure

5 ..... Raw water inlet 6 ..... Outlet

7 ..... Membrane Channel 8 ..... current collector

       9 ... Membrane 10 ..... supporter

The present invention relates to a membrane for capacitive deionization (CDI) of wastewater or brine. More specifically, the flow path of a solution to be treated during a CDI process in a separator of a CDI apparatus for removing ions of wastewater or brine. The present invention relates to a membrane for deionization of wastewater or brine capable of preventing the contact between the positive electrode and the negative electrode while maintaining a smooth state, and a method for removing ions of the wastewater or brine using the same.

Conventionally, applications using a separator have been used in the development of a solid polymer electrolyte fuel cell (Korean Patent Publication No. 2001-0070030), and in the case of using a cationic and / or anion selective membrane as a separator in wastewater treatment ( Salem et al., Desalination, 101 (1995) 123). However, in the CDI process, a separator is not used separately to smoothly flow the solution.

The CDI process was first developed by Joseph C. Farmer of Lawrence Livermore National Laboratory, California, USA, using a principle that removes impurities and salts from water by constructing a porous carbon electrode in stack form ( Lawrence W. Hrubesh, Journal of Non-Crystalline Solids, 225 (1998) 335; JC Farmer et al., Journal of Non-Crystalline Solids, 225 (1998) 74). When a solution containing a cation and an anion passes between two porous carbon electrode layers, ions contained in water are removed by applying an electrostatic force. Anions such as Cl ⁻ are moved to the positive electrode by the electrostatic force, and cations such as Na ⁺ are transferred to the negative electrode, so that charging is performed, and water is discharged in a pure form in which ions are removed. Will be. In the CDI process, by flowing clean water, ions charged in the electric double layer are discharged into water, thereby simplifying the regeneration of the electrode.

Until now, among various kinds of methods for purifying water containing salt components or heavy metals, many methods using ion exchange resins have been used. However, the method of using an ion exchange resin has an economical disadvantage because an acid or basic solution should be used when regenerating the resin, and a large amount of polymer resin and chemicals should be used to treat a large amount of water. However, the CDI process is an economical and effective process because it effectively removes the ions in the solution and is simple in regeneration and has a low specific gravity.

It has been recognized as a core part of the CDI process until now to achieve effective double layer charging with a porous carbon electrode. In general, the surface area should be about 600 ~ 1000㎡ / g. The pore size should be in the form of mesopores, not micropores. In addition, it is important to manufacture an electrolytic cell for durability of the carbon electrode, and durability can be increased by using the carbon electrode together with a current collector.

However, in the CDI process, the manufacture of the optimum separator is the most important part in designing the electrolytic cell to withstand the rapid flow of the fluid. Most existing CDI related studies have not used a separator (US Patent No. 5,954,937; US Patent 5,538,611; US Patent 6,906,179, etc.).                         

Looking at the principle of the CDI reaction in more detail, the CDI apparatus exhibits an electrochemical adsorption reaction consisting of the following formulas 1 and 2 on the anode side and the cathode side by supplying the same wastewater (ion solution) to the anode and the cathode.

Scheme 1

X ^{m +} → X ^{m +} ad / carbon

Scheme 2

Y ^n- → Y ^n- ad / carbon

(In the scheme 1 and 2, X = cations (e. G., Metal ions), Y = anion _{^{(e.g., Cl -, SO 4 2-,}} NO 3 - , and so on), the number of the cations used for reaction m = E, n = number of electrons of the anions used in the ^reaction means (for example, SO ₄ ^2-, and when the n is 2, Cl when n is 1, the search), and ad = adsorption (adsorption))

By such a chemical reaction, the anion and the cation can be removed by adsorption with high efficiency. That is, at this time, the anion and the cation do not undergo a redox reaction, and remain strong by the capacitive ability of carbon on the surface of the carbon electrode.

In the separation membrane of the CDI apparatus that removes the ions of the wastewater as described above, in order to more effectively treat the wastewater, the insulation of the anode and the cathode is prevented while maintaining the flow path of the solution to be treated smoothly during the CDI process. Formation of good materials is required.

Accordingly, an object of the present invention is to provide a separator for deionization of wastewater or brine that can prevent the contact between the positive electrode and the negative electrode while maintaining the flow path of the solution to be treated during the deionization process.

Another object of the present invention is to provide a method for removing ions of wastewater or brine using the separator.

According to one aspect of the present invention, a separator for ion removal, comprising a polycarbonate, having a plurality of groove-shaped channels that are dug to a thickness of less than 1 to 2 mm from both sides or one side, the raw water inlet connected to one side A separator for capacitive deionization (CDI) of wastewater or brine is provided, characterized in that it comprises an outlet connected to the other side.

According to another aspect of the present invention, in the method for removing ions of wastewater or brine through a power storage deionization process, at least one separator is placed between an anode and a cathode of a power storage deionization device, and then the wastewater or brine is separated from the separator. Separation of the wastewater or brine into sewage and deionized water containing anions and cations by passing through the present invention is provided.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.                     

The inventors of the present invention, when using a specific material excellent in insulation, but excellent in impact resistance, heat resistance, weather resistance, self-extinguishing, transparency, etc. to optimize the CDI device principle to produce a separation membrane, the anode while maintaining the flow path of the solution to be treated smoothly The present invention has been completed by finding a separator for deionization of waste water or brine capable of preventing contact between a cathode and a cathode.

As a material suitable for the present invention, polycarbonate (polycabonate), acrylic, Teflon, polychlorotrifluoroethylene (eg, Kel-f (3M)) and the like can be used, which is processed in accordance with the principle of CDI device to the waste water flow path It constitutes a separator that serves to facilitate the flow.

Polycarbonate is most preferably used as a material constituting the separator of the present invention, and the chemical formula may be represented as follows.

Polycarbonate is a kind of polyester having a condensed structure of carbonic acid (H ₂ CO ₃ , HO-CO-OH), diol and HO-R-OH, and commercially synthesized polycarbonate from bisphenol A and phosgene (Polycabonate) has high light diffusivity, high visible light transmittance, shows clear surface gloss like plate glass, and has excellent weather resistance, so it can maintain high physical properties for a long time and maintain performance even with temperature changes. Has suitable properties.

The polycarbonate in the present invention may be composed of a resin layer (resin) + glass fiber layer (fiber glass) + resin layer (resin). When configured in this way, it has a strength of 150 times or more of the existing tempered glass, 250 times of the plate glass, 30 times of the acrylic, excellent electrical insulation, and the specific gravity is light weight about 1/2 of the glass.

Teflon, acrylic, and polychlorotrifluoroethylene (eg, Kel-f (3M)) may be used as materials for forming the separator of the present invention. Under the conditions in which the membrane is to be manufactured and Kel-f can be selected and used in consideration of durability.

If the carbon electrode area is 50mm x 50mm in width, the size of the current collector and the separator should be 70mm x 70mm, and the channel only needs to be formed as much as the carbon size. That is, the overall size of the channel portion is 50mm wide x 50mm long. In the separation membrane of the present invention, the channel has a plurality of groove-shaped channels that are dug to a thickness of less than 1 to 2 mm on both sides, and water is allowed to pass through. If the channel thickness is less than 1mm, the flow of the solution may not be smooth and the pressure in the cell may be increased, which may cause the solution to leak. If it exceeds 2mm, the solution cannot contact with the carbon electrode sufficiently to react, which causes a decrease in the removal efficiency of ions in the waste solution. In this case, the channels may be configured such that each channel crosses each other in up, down, left and right. The size of the channel is preferably 1 to 2 mm in both the length and width of the channel. In addition, the interval between each channel is preferably 1 ~ 2mm, the interval is appropriately selected and adjusted according to the size and the number of use of the carbon anode and cathode. If the size of the electrode increases, the spacing of the channels must also increase. For example, if the size of the electrode is 100 mm x 100 mm, the channel depth should be at least 2 mm and no more than 4 mm, respectively.

In addition, the separator of the present invention has a raw water inlet connected to one side and an outlet connected to the other side. The inlets and outlets may be placed at appropriate locations to allow the raw water to flow in and out.

As for the thickness of the separator of this invention, 2-5 mm is preferable. If the thickness of the separator is too thin, the flow of the solution may not be smooth and the pressure in the cell may be increased, which may cause leakage of the solution, and if the thickness is too thick, the solution may sufficiently react with the carbon electrode to react. Therefore, the reduction of the removal efficiency of the ions in the waste solution can be caused. In addition, if the thickness of the separator is less than 2mm, the size of the channel is less than 1mm, and if it exceeds 5mm, it is preferable to make the size of the channel more than 2.5mm, wherein the thickness of the separator is used carbon Select and adjust according to the size and number of anodes and cathodes.

The separator of the present invention is placed between the positive electrode and the negative electrode of the storage deionization device in use, and when effluent or brine flows into the ions, the ions move to both electrodes and the purified water is discharged to the outlet of the separator to be purified.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail the present invention.

<Examples>

1 is a schematic diagram showing the principle of a CDI apparatus to which the present invention is applied. As shown in FIG. 1, the solution to be treated (3) flows through the carbon cathode (1) and the carbon anode (2). At this time, when an optimum voltage is applied, anions and cations are adsorbed to the cathode and the anode, respectively. As a result, pure water 4 can be obtained.

Figure 2 is a view showing in detail the separation membrane for CDI of the wastewater or brine of the present invention. The material of the separator is made of polycarbonate, and consists of an inlet (5) and a drain (6) of the treatment solution and a channel (7) of the separator. The thickness of the separator was 3mm, the interval of the channel is 1mm and the diameter of the inlet was prepared by 2mm. The depth of the channel was prepared by staggering up and down and left and right by 1mm on each side. The size of the above-mentioned separator is the optimum value for the separator for continuous CDI apparatus using five carbon anodes and cathodes of 25 cm 2 each.

3 is a view showing a CDI device for wastewater treatment completed by combining the separator, the current collector and the carbon electrode of the present invention. As a continuous CDI wastewater treatment device, all five separators 9 were used. The separators had an area of 6 cm wide and 6 cm long, that is, 36 cm 2, with a thickness of 3 mm and grooved to a depth of 1 mm on both sides. It is. The carbon area of the negative electrode and the positive electrode is 25 cm 2, respectively, and is composed of five reaction chambers. The cell is composed of a current collector 9, an aluminum support plate 10, and a tightening device 11 for preventing leakage of the solution and reducing cell resistance due to excellent contact between the separator, the treatment liquid, and the carbon electrode.

In FIGS. 2 and 3, the size of the anode and cathode carbon electrodes is 15 cm wide and 15 cm long, and the electrode area is 225 cm 2 and the number of electrodes used is 10 or more, respectively. , 17 cm wide by 17 cm long, that is, 289 cm 2). This is because when the thickness of the separator is less than 3mm, it is not possible to apply force uniformly to all parts of the separator when assembling the multilayer cell by the tightening device.

The separator of the present invention prevents electrical shorts by preventing the contact between the carbon anode and the carbon cathode during the CDI process, and has a uniform channel to facilitate the flow of the waste liquid to be treated, and sufficient separation between the waste liquid to be treated and the carbon anode and the cathode. It has the effect of causing reactivity.

Claims (5)

In the separation membrane for ion removal, It consists of a material selected from the group consisting of polycarbonate, teflon, acrylic and polychlorotrifluoroethylene, having a plurality of channels in the form of grooves cut into a thickness of less than 1 to 2 mm from both sides or one side, connected to one side Separation membrane for capacitive deionization (CDI) of wastewater or brine, characterized in that it comprises a source inlet and an outlet connected to the other side. According to claim 1, wherein the thickness of the separator is characterized in that the waste water or brine separator for deionization of the waste water, characterized in that 2 ~ 5mm. The membrane of claim 1, wherein the channels cross each other vertically and horizontally. The separation membrane for storage deionization of wastewater or brine according to claim 1, wherein the distance between each channel is 1 to 3 mm. In the deionization method of wastewater or brine through power storage deionization process, At least one separator of claim 1 is placed between the positive electrode and the negative electrode of the deionization apparatus, and the wastewater or brine is passed through the separator to separate the wastewater or brine into sewage and deionized water containing anions and cations. Characterized in that it comprises a step of removing, waste water or brine ion removal method.

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