KR101137042B1 - Capacitive deionization device, Method for capacitively deionizing, and Desalination apparatus, Wastewater treatment apparatus using the same - Google Patents

Abstract

An electricity storage deionization apparatus, an electricity storage deionization method using the same, a desalination apparatus using the same, and a wastewater treatment apparatus are provided.

In the capacitive deionization apparatus of the present invention, the capacitive deionization apparatus including the positive electrode, the negative electrode, and the separator, wherein the positive electrode and the negative electrode are perpendicular to the direction in which the ion-containing solution flows, and the ion-containing solution is the positive electrode and the negative electrode. It is characterized in that the permeation, increase the relative contact area of the waste water or brine and the electrode in the power storage deionization process to improve the decontamination or ion adsorption performance, the fluid passes directly through the bubbles of the electrode during electrode regeneration, effective electrode Induction of regeneration shortens the electrode regeneration time and has the effect of easily controlling the maintenance and management of the device.

Description

 Capacitive deionization device, Method for capacitively deionizing, and Desalination apparatus, Wastewater treatment apparatus using the same

The present invention relates to a capacitive deionization apparatus, a capacitive deionization method using the same, a desalination apparatus using the same, and a wastewater treatment apparatus, and more particularly, to increase the relative contact area of the wastewater or the brine and the electrode during the deionization, Capacitive desorption can improve ion adsorption performance, fluid flows directly through electrode bubbles during electrode regeneration, inducing effective electrode regeneration, shortening electrode regeneration time, and controlling device maintenance and management easily The present invention relates to an ionization apparatus, an electricity storage deionization method using the same, a desalination apparatus, and a wastewater treatment apparatus using the same.

Recently, as social concern about water pollution and water shortages is increasing, the application and combination system of various water treatment technologies including salt water desalination, which has been used in large ships in the past, and the development of high efficiency thereof are being developed. These water treatment technologies can be broadly classified into physical treatment methods such as evaporation distillation or reverse osmosis membrane separation, biochemical treatment methods such as biodegradation or chemical oxidation and precipitation, and electrochemical treatment methods such as electrodialysis or ion exchange. The desalination techniques commonly used include evaporation, membrane separation, and ion exchange.

An electrochemical deionization (CDI) process, an example of the electrochemical treatment of the above methods, was first developed by Joseph C. Farmer of Lawrence Livermore National Laboratory, California, USA, which stacks porous carbon electrodes. It is a process based on the principle of removing impurities or salts in water by forming a stack (Lawrence W. Hrubesh, Journal of Non-Crystalline Solids, 225 (1998) 335; JC Farmer et al., Journal of Non-Crystalline Solids, 225 (1998) 74). The method removes ions contained in water by applying an electrostatic force when a solution containing cations and anions such as brine passes between two porous carbon electrode layers, and removes Cl ^{− from the} positive electrode to the positive electrode by the electrostatic force. The negative electrode, such as the negative electrode (negative electrode), such as Na ⁺ cation is transferred to the charge is made, the water is discharged in the form of pure ions removed.

Until now, among the various types of methods for purifying water containing salts or heavy metals, many methods using ion exchangeresins 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 chemical should be used to treat a large amount of water. Therefore, the electrical desorption deionization process is an economical and effective process because it effectively removes ions in the solution and is simple in regeneration and has a low specific gravity.

 However, in general, the deionization method of the electricity storage has a small energy consumption for desalination compared to the evaporation and membrane filtration methods (RO, ED, etc.), but due to technical limitations, a large-capacity brine having a high concentration, such as seawater, is presently used. There is a disadvantage that it is not suitable for desalination and wastewater treatment, and it is also inefficient because it needs to be regenerated again.

1 is a schematic diagram of a desalination apparatus of the electrosorption method disclosed in Korean Laid-Open Patent Publication No. 2002-0076629.

Referring to FIG. 1, it can be seen that a fluid such as seawater containing ions passes through a channel between a positive electrode and a negative electrode, and ions are adsorbed in this process. However, in this case, in order to treat a large amount of seawater, an electrode of infinitely large surface area must be used, which is practically impossible, and this capacity limitation has been a big limitation of the capacitive deionization apparatus.

Accordingly, the first problem to be solved by the present invention is to provide a capacitive deionization device of a new structure having a higher efficiency than the prior art.

In addition, a second problem to be solved by the present invention is to provide a new type of capacitive deionization method that can achieve a higher efficiency than the prior art.

In addition, a third problem to be solved by the present invention is to provide a utilization method using the capacitive deionization device.

In order to solve the first problem, the present invention is a capacitive deionization device including a positive electrode, a negative electrode and a separator, the positive electrode and the negative electrode is perpendicular to the flow direction of the ion-containing solution flows, the ion-containing solution is Provided is a capacitive deionization device that transmits a positive electrode and a negative electrode.

The positive electrode and the negative electrode have a fine pore structure, the ion-containing solution is permeated through the fine pores, the positive electrode and the negative electrode may be made of activated carbon, or may include a nickel foam, the specific surface area of the activated carbon is 1000 To 1500 m ² / g.

In addition, the positive electrode and the negative electrode are separated by the separator, a plurality of positive electrodes and negative electrodes are spaced at a predetermined interval and repeated, it may be a stacked structure. In one embodiment of the present invention, the electrode permeation rate of the ion-containing solution may be 10 to 100 ml / min.

In order to solve the second problem, the present invention In the capacitive deionization method using a positive electrode and a negative electrode, the capacitive deionization method provides a capacitive deionization method comprising adsorbing the ions to the electrode in such a manner that a ion-containing solution is allowed to pass through the positive electrode and the negative electrode. .

Permeation of the ion-containing solution may be performed through fine pores formed in the positive electrode and the negative electrode, and the positive electrode and the negative electrode may be made of activated carbon or may include nickel foam, and the specific surface area of the activated carbon is 1000 to 1500 m. May be ² / g.

In order to solve the third problem, the present invention provides a desalination apparatus or a wastewater treatment apparatus using the capacitive deionization apparatus.

Capacitor deionization apparatus according to the present invention can improve the decontamination or ion adsorption performance by increasing the relative contact area of the waste water or the brine and the electrode in the capacitive deionization process. In addition, when the electrode regeneration, the fluid directly passes through the bubbles of the electrode, induces effective electrode regeneration to shorten the electrode regeneration time, there is an effect that can easily control the maintenance and management of the device.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings and examples. However, the specific configuration illustrated through the drawings and embodiments, etc. below are intended to illustrate all of the present invention, the scope of the present invention is not limited or limited thereto.

The conventional capacitive deionization device is an ion adsorption method through contact between a fluid flowing through an electrode surface and an electrode, as described with reference to FIG. 1. However, in this case, since the entire adsorption is performed only on the surface of the electrode, there is a problem that the cross-sectional area of the electrode must be infinitely increased in order to adsorb a large amount of ions. In addition, since the desorption ionizer desorbs ions only by an electrochemical method in an essential electrode regeneration step, there is a problem in that the regeneration time is relatively long.

The present inventors solved this problem by applying an electrode through which the ion-containing fluid can permeate to the capacitive deionization apparatus, which will be described in more detail with reference to the accompanying drawings and experimental examples.

2 is a cross-sectional view of a capacitive deionization apparatus according to an embodiment of the present invention.

Referring to FIG. 2, the electrode assembly used in the capacitive deionization apparatus of the present invention includes electrodes 1 and 2 and a separator 3. In addition, protrusions for voltage application are formed in upper and lower frames of each electrode, and electrodes having different polarities (that is, positive and negative electrodes) are alternately disposed, and separators are provided between the electrodes. In particular, the electrode and separator have a fine pore structure through which an ion-containing solution such as seawater or wastewater is permeated. Thus, as in the prior art, the ion adsorption only on the surface has been extended to the inside of the electrode, which not only increases the ion adsorption area but also causes an effect of increasing the rate of ion desorption by the solution flowing therein. That is, in the conventional capacitive deionization apparatus as described above, the electrodes are arranged in a configuration in which the flow direction of the electrode is parallel to the flow direction of the brine, and only the diffusion is used to remove ions. By being perpendicular to the flow direction of the brine, the brine passes directly through the electrode to increase the regeneration efficiency (ie, ion desorption efficiency).

In one embodiment of the present invention, the electrode and the separator are made of a porous material having fine pores through which fluid can pass, and in one embodiment of the present invention, activated carbon is used as the electrode material, and in another embodiment, Nickel foam is used as the electrode material. In particular, since activated carbon has a specific surface area of 100 times that of nickel foam, a high deionization effect can be expected, and therefore, more preferable. In addition, when the electrode material is used as activated carbon, the electrode permeation rate of the ion-containing solution is preferably 10 to 100 ml / min. The ion permeation rate of the ion-containing solution is less than the above range. On the contrary, in the case of exceeding the above range, there is a problem that ions adsorbed in the surface or the electrode may fall back from the electrode. In addition, when using activated carbon as an electrode, the fine pore size is preferably 2 to 30 nm, because if it is less than the above range, it is difficult to achieve a sufficient transmission effect, and if it exceeds the above range, a sufficient specific surface area cannot be obtained. to be. However, according to the structure of the electrode itself to achieve a sufficient specific surface area, a carbon material having a pore size of several hundred nm size can be used, which is within the scope of the present invention.

Figure 3 is a schematic diagram showing the overall appearance of the electrode assembly of the present invention.

Referring to Figure 3, in order to maintain the shape of the electrode assembly having a characteristic that the fluid penetrates the electrode, the electrode assembly is provided with a support 6, and also provided with an inlet 7 for the inflow of wastewater or seawater do. An electrode 5 and a separator 4 are alternately arranged between both ends of the support. In addition, the upper and lower frames of each electrode are provided with a protrusion 8 for applying voltage outside the support. In addition, the electrode of the electrode assembly uses a porous material such as activated carbon so that the fluid flow can be vertically transmitted.

Capacitive deionization apparatus having an electrode assembly of such a structure can be utilized as a desalination process of brine or a treatment apparatus for wastewater containing ions, and can be used for ion removal for various other purposes.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

Example  One

Example  1-1

Electrode material

Ni was used as an electrode material of a capacitive deionization device, and in particular, the electrode was manufactured and used in the form of a porous metal foam to improve ion adsorption efficiency and direct passage of a fluid. The electrode sheet was cut to 11.5 × 11.5 cm ² and a separator using a nonwoven fabric was also manufactured in the same size to prevent short circuit with the nickel foam as the current collector. The metal (nickel) foam was 110 ppi (pore per inch). However, various materials can be used as the electrode material, and particularly porous materials such as activated carbon can be used very effectively.

Example  1-2

Device manufacturing

As described above, a nonwoven fabric was used as a separator for preventing a short circuit between two identical nickel electrodes and maintaining the same spacing between the electrodes. The electrode for applying a voltage is a type in which a current collector is directly applied to an electrode rod disposed at the center of opposite corners of a square electrode assembly in which voltage is applied, and protrusions are formed at one corner of each current collector. This part was produced in such a way that the electrode was sandwiched (see FIG. 4). In addition, the electrodes, current collectors, and separators in the electrode assembly were alternately arranged one by one (see FIG. 5), and a total of 176 electrodes were used. After the final arrangement in the electrode assembly was finished with a deterioration epoxy to prevent the leakage of the fluid, as a result, the electrode assembly of the final capacitive deionization device shown in Figure 7 was prepared. Then, both ends of the electrode assembly is provided with a discharge port for entering and exiting the fluid, the lower portion of the electrode assembly is formed with an outlet for removing the fluid contained in the device after the experiment. Exhaust ports at both ends except the outlet located at the bottom are finally connected to one pipe, and both ends of the pipe are drilled to allow the fluid to pass through for the experiment, but valves are provided at each position to free the flow path. Control is possible. The electrode assembly is installed in a direction parallel to the ground, and as ancillary devices, a pump and a power supply (see FIG. 6) are used.

Experimental Example  One

Experiment method

In this experiment, the fluid was passed through the electrode directly. When the concentration of brine was 500uS, the experiment was performed according to the presence or absence of the flow rate, and when the flow rate was constant, the experiment was performed to determine the decontamination performance by experimenting at 118uS, 466uS and 946uS. In this experiment, the flow rate was fixed at 50ml / min, voltage was 1.0V, each experiment was performed at room temperature based on 60 minutes.

Experimental Example  1-1

Electromotive force  Measure (118) uS , 466 uS , 946 uS )

8 to 10 are graphs showing the electromotive force at the brine concentrations of 118 uS, 466 uS and 946 uS, respectively.

Referring to FIGS. 8 to 10, it can be clearly seen that the effect of brine ions being adsorbed on the electrode and removed over time.

Experimental Example  1-2

Concentration Measurement (118 uS , 466 uS , 946 uS )

11 to 13 are graphs respectively measuring the brine concentration after the power storage deionization apparatus according to the present invention.

11 to 13, similar to Experimental Example 1-1, it can be seen that the brine concentration is significantly reduced. The above results mean that sufficient ion removal effect can be achieved, especially when using a transmissive electrode, which indicates that the capacitive deionization device according to the present invention can be effectively used for desalination devices and wastewater treatment devices.

1 is a schematic diagram of a desalination apparatus of the electrosorption method disclosed in Korean Laid-Open Patent Publication No. 2002-0076629.

2 is a cross-sectional view of a capacitive deionization apparatus according to an embodiment of the present invention.

Figure 3 is a schematic diagram showing the overall appearance of the electrode assembly of the present invention.

4 to 7 are photographs showing the electrode assembly manufacturing process according to the present invention.

8 to 10 are graphs showing electromotive force when the brine concentration is 118 uS, 466 uS and 946 uS, respectively.

11 to 13 are graphs respectively measuring the brine concentration after the power storage deionization apparatus according to the present invention.

Claims (14)

In the capacitive deionization apparatus including a positive electrode and a negative electrode, The positive electrode and the negative electrode has a fine pore structure, perpendicular to the direction of the flow of the ion-containing solution flows in, the ion-containing solution penetrates through the fine pores of the positive electrode and the negative electrode, characterized in that the transmission deionization device. delete The method of claim 1, The positive electrode and the negative electrode capacitive deionization device, characterized in that made of activated carbon. The method of claim 3, The positive electrode and the negative electrode capacitive deionization device, characterized in that the nickel foam. The method of claim 3, The specific surface area of the activated carbon is 1000 to 1500m ² / g, the degeneration of the power storage device, characterized in that. The method of claim 1, The positive electrode and the negative electrode are separated by a separating plate, the plurality of positive electrode and the negative electrode are repeated, spaced apart at a predetermined interval, the capacitive deionization device, characterized in that stacked. The method of claim 1, The electrode permeation rate of the ion-containing solution is 10 to 100ml / min Capacitive deionization device, characterized in that. delete delete delete delete delete delete delete

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