Electrolysis equipment

Abstract

To provide an electrolytic device capable of efficiently separating heavy water from treated water.SOLUTION: An electrolytic device 1 includes: an anode chamber 2 having an inflow port 2A and an outflow port 2B; a cathode chamber 3 having an outflow port 3A and an outflow port 3B; and an intermediate chamber 4 having an inflow port 4A and an outflow port 4B, arranged between the anode chamber 2 and the cathode chamber 3, and filled with a cation exchange resin 4C therein. The electrolytic device is further provided with: a strongly acidic first cation exchange membrane 5 and a positive electrode 6 between the anode chamber 2 and the intermediate chamber 4; and a strongly acidic second cation exchange membrane 7 and a negative electrode 8 between a cathode chamber 3 and the intermediate chamber 4. The electrolytic device is configured to: cause water to flow from the inflow port 2A to the anode chamber 2 and to be discharged from the outflow port 2B; while causing air to flow into the intermediate chamber 4, cause treated water containing heavy water to flow into the intermediate chamber 4 from the inflow port 4A and to pass through the cation exchange resin 4C; and then, to be discharged from the outflow port 4B; and cause the moving water having moved from the intermediate chamber 4 to the cathode chamber 3, to circulate to the intermediate chamber 4.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an electrolysis device for electrolyzing treated water containing heavy water.

Background Art

[0002] Heavy water has physical properties such as electrical conductivity and ionization degree different from those of ordinary water (light water). It is known that if a large amount of heavy water is ingested into the body, it will cause a disorder in the in-vivo reaction. Therefore, a device or method capable of separating heavy water as safely as possible from treated water containing heavy water is desired.

[0003] So far, electrolysis methods for controlling the concentration of heavy water by electrolysis have been disclosed (for example, Patent Document 1 and Patent Document 2). The electrolysis method disclosed in Patent Document 1 is to electrolyze an electrolytic solution filled in an electrolytic cell partitioned into an anode chamber and a cathode chamber by an ion exchange membrane and containing water containing deuterium by energizing the electrolytic solution to generate hydrogen and oxygen, thereby concentrating deuterium. Further, the method disclosed in Patent Document 2 uses a conductive material supporting a metal which is silver, gold, copper or an alloy thereof for the cathode electrode in order to produce water in which deuterium is selectively concentrated by a cathode electrode reaction from hydrogen isotope mixed water. This supported metal exhibits localized surface plasmon resonance characteristics, and at the cathode, a gas is generated from the hydrogen isotope mixed water to obtain water with an increased deuterium concentration in the hydrogen isotope mixed water.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, the amount of treated water containing heavy water has increased, and there is a greater need than ever for equipment and methods that can separate heavy water and other substances from treated water containing hydrogen isotope mixtures.

[0006] Therefore, the present invention aims to provide an electrolytic device that can efficiently separate heavy water from treated water. [Means for solving the problem]

[0007] The electrolytic apparatus according to the present invention comprises an anode chamber having a first opening and a second opening, a cathode chamber having a third opening and a fourth opening, and an intermediate chamber having a fifth opening and a sixth opening, and positioned between the anode chamber and the cathode chamber, with an ion exchange resin filling the interior. A first cation exchange membrane and a positive electrode are provided between the anode chamber and the intermediate chamber, and a second cation exchange membrane and a negative electrode are provided between the cathode chamber and the intermediate chamber. Water is introduced into the anode chamber from the first opening and discharged from the second opening, and air is introduced into the intermediate chamber. Treated water containing heavy water is introduced into the intermediate chamber from the fifth opening, passes through the ion exchange resin, and is then discharged from the sixth opening. The migrated water that has moved from the intermediate chamber to the cathode chamber is circulated back into the intermediate chamber.

[0008] The electrolytic apparatus according to the present invention is characterized in that a hydrogen ion selective permeable membrane is provided superimposed on the first cation exchange membrane, and the positive electrode, the first cation exchange membrane, and the hydrogen ion selective permeable membrane are arranged in that order from the anode chamber side. [Effects of the Invention]

[0009] The electrolytic apparatus according to the present invention allows treated water to flow into an intermediate chamber from a fifth opening, pass through an ion exchange resin, and then circulates the migrated water, which has moved from the intermediate chamber to the cathode chamber, back into the intermediate chamber, while introducing air into the intermediate chamber. This electrolytic apparatus can separate heavy water and efficiently remove it from treated water.

[0010] In the electrolytic apparatus according to the present invention, a hydrogen ion selective permeable membrane is provided on top of the first cation exchange membrane, and by arranging the positive electrode, the first cation exchange membrane, and the hydrogen ion selective permeable membrane in that order from the anode chamber side, heavy water can be separated from treated water more efficiently. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram of an electrolytic apparatus according to an embodiment of the present invention. [Figure 2] This is a schematic diagram of an electrolytic treatment system including an electrolytic device according to an embodiment of the present invention. [Modes for carrying out the invention]

[0012] The electrolytic apparatus according to this embodiment will be described with reference to Figures 1 and 2. Figure 1 shows the electrolytic apparatus, and Figure 2 shows an electrolytic processing system using this electrolytic apparatus.

[0013] First, the electrolytic apparatus 1 according to this embodiment will be described. As shown in Figure 1, the electrolytic apparatus 1 is a three-chamber type electrolytic apparatus comprising an anode chamber 2, a cathode chamber 3 positioned opposite the anode chamber 2, and an intermediate chamber 4 positioned between the anode chamber 2 and the cathode chamber 3. Between the anode chamber 2 and the intermediate chamber 4, a positive electrode 6, a strongly acidic first cation exchange membrane 5, and a hydrogen ion selective permeable membrane 5A are provided in that order from the anode chamber 2 side. The hydrogen ion selective permeable membrane 5A is provided on top of the strongly acidic first cation exchange membrane 5 and is positioned in contact with the strongly acidic first cation exchange membrane 5. On the other hand, between the cathode chamber 3 and the intermediate chamber 4, a negative electrode 8 and a strongly acidic second cation exchange membrane 7 are provided in that order from the cathode chamber 3 side. In addition, multiple magnets 9 are provided on the outside of the anode chamber 2, and multiple magnets 10 are provided on the outside of the cathode chamber 3.

[0014] [Anode Chamber 2] The anode chamber 2 has an inlet (first opening) 2A and an outlet (second opening) 2B formed on the side opposite to the inlet 2A. As shown in Figure 2, the inlet 2A is connected to the water tank 20 via a flow path 21, and the outlet 2B is connected to the water tank 20 via a flow path 22. Water flowing out of the anode chamber 2 passes through the flow path 22 and flows into the water tank 20, and then passes through the flow path 21 and flows back into the anode chamber 2. A flow rate control device (not shown) is provided in the flow path 21, and this flow rate control device adjusts the flow rate of water supplied from the water tank 20 to the anode chamber 2. Pure water or tap water is used for the water flowing into the anode chamber 2.

[0015] Multiple magnets 9 are provided on the outer side surface of the anode chamber 2. For example, annular neodymium magnets can be used for these magnets 9. The number, strength, and fixing positions of the magnets 9 are determined as appropriate. Preferably, these magnets 9 are provided in a position opposite to the magnet 10 provided in the cathode chamber 3, which will be described later.

[0016] [Cathode Chamber 3] The cathode chamber 3 has an outlet (third opening) 3A and an outlet (fourth opening) 3B formed on the side opposite to outlet 3A. Outlet 3B is connected to the treated water tank 40 via a flow path 32. The liquid accumulated in the cathode chamber 3 flows into the treated water tank 40 through outlet 3B and the flow path 32. In addition, hydrogen generated in the cathode chamber 3 is discharged to the outside of the cathode chamber 3 through outlet 3A.

[0017] Multiple magnets 10 are provided on the outer side surface of the cathode chamber 3. Similar to magnet 9, these magnets 10 can be, for example, annular neodymium magnets. The number, strength, and fixing positions of the magnets 10 can be changed as appropriate. These magnets 10 are positioned opposite to the magnet 9 provided in the anode chamber 2.

[0018] [Intermediate Room 4] The intermediate chamber 4 has an inlet (fifth opening) 4A and an outlet (sixth opening) 4B formed on the side opposite to the inlet 4A. As shown in FIG. 2, the inlet 4A is connected to the treated water tank 40 via the flow path 41, and the outlet 4B is connected to the treated water tank 40 via the flow path 42. The treated water electrolyzed in the intermediate chamber 4 flows through the flow path 42 and into the treated water tank 40, and then flows through the flow path 41 and into the intermediate chamber 4 again. A flow rate adjusting device (not shown) is provided in the flow path 41, and the flow rate of the treated water supplied from the treated water tank 40 to the intermediate chamber 4 is adjusted by this flow rate adjusting device.

[0019] The inside of the intermediate chamber 4 is filled with a cation exchange resin 4C. For example, a gel type (gel type structure ion exchange resin) or a macroporous type (macroporous type structure ion exchange resin) can be used as the cation exchange resin 4C. The treated water flowing into the intermediate chamber 4 passes through the cation exchange resin 4C and flows out from the outlet 4B. The treated water tank 40 is held in the bathtub, and the temperature of the treated water inside the treated water tank 40 is maintained at a constant temperature. The temperature of the treated water flowing from the treated water tank 40 into the intermediate chamber 4 is preferably from 1 degree to 5 degrees.

[0020] Also, a pump 43 is connected to the inlet 4A of the intermediate chamber 4 via the flow path 44. The pump 43 sends air in the atmosphere into the flow path 44. For example, a peristaltic pump can be used as the pump 43, and the air passing through the flow path 44 flows into the intermediate chamber 4 from the inlet 4A. When an electrolysis is performed by providing a hydrogen ion selective permeable membrane 5A, bubbles are generated in the intermediate chamber 4 and the voltage increases. Therefore, air is sent into the intermediate chamber 4 to remove the generated bubbles, thereby preventing the voltage from becoming excessively large.

[0021] Between the anode chamber 2 and the intermediate chamber 4, from the anode chamber 2 side, a positive electrode 6, a strongly acidic first cation exchange membrane 5, and a hydrogen ion selective permeable membrane 5A are provided so as to partition the anode chamber 2 and the intermediate chamber 4. On the other hand, between the cathode chamber 3 and the intermediate chamber 4, from the intermediate chamber 4 side, a strongly acidic second cation exchange membrane 7 and a negative electrode 8 are provided so as to partition the cathode chamber 3 and the intermediate chamber 4. The positive electrode 6 and the negative electrode 8 are respectively connected to a constant current power source 50.

[0022] The electrolysis method using the electrolysis apparatus 1 according to the present embodiment is as follows: water is allowed to flow into the anode chamber 2 from the inlet 2A and discharged from the outlet 2B, and the treated water containing heavy water is allowed to flow into the intermediate chamber 4 from the inlet 4A, passed through the cation exchange resin 4C, and then discharged from the outlet 4B. Further, the moving water that has moved from the intermediate chamber 4 to the cathode chamber 3 is returned to the treated water tank 40 through the flow path 32 and circulated again into the intermediate chamber 4. At this time, air is allowed to flow into the intermediate chamber 4 from the inlet 4A.

[0023] [Examples] Using the electrolysis treatment system 100 shown in FIG. 2 for the treated water containing heavy water, the separation factor of heavy water in each example was examined. Experiments were conducted using treated water with an initial heavy water concentration of 2000 ppm to 5000 ppm and a pH of 3.0 to 7.0. Two types of cation exchange resins 4C, namely a gel type and a macroporous type, were used to fill the inside of the intermediate chamber 4. Pure water was allowed to flow into the anode chamber 2 at a flow rate of 0.1 L / min to 1.0 L / min, and the treated water at 1 to 5 degrees was allowed to flow into the intermediate chamber 4 at a flow rate of 0.01 L / min to 0.5 L / min. Strongly acidic (Na type) (manufactured by Asahi Kasei Corporation: CMB) was used for the strongly acidic first cation exchange membrane 5 and the strongly acidic second cation exchange membrane 7, and HSFN (manufactured by AC Engineering Co., Ltd.) was used for the hydrogen ion selective permeable membrane 5A.

[0024] The current value of the constant current power source 50 was set to 16 A or 20 A, and electrolysis was performed for a certain period of time to examine the separation factor of heavy water at each current value. The separation factor was calculated from the concentration of heavy water in the moving water flowing out from the outlet 3B. The separation factor was calculated from the following calculation formula. Separation coefficient = {("Initial heavy water concentration in the intermediate chamber" - "Heavy water concentration in the intermediate chamber after electrolysis for a certain period of time") / "Initial heavy water concentration in the intermediate chamber"} + 1.0

[0025] The following conditions were met. In [Example 1], the hydrogen ion selective permeable membrane 5A was not provided, and the moving water that had moved from the intermediate chamber 4 to the cathode chamber 3 was circulated back to the intermediate chamber 4. At this time, air was introduced into the intermediate chamber 4 from the inlet 4A and discharged from the outlet 4B. In [Example 2], the hydrogen ion selective permeable membrane 5A was provided, and the moving water that had moved from the intermediate chamber 4 to the cathode chamber 3 was returned to the treated water tank 40 via the flow path 32 and circulated back to the intermediate chamber 4. At this time, air was introduced into the intermediate chamber 4 from the inlet 4A and discharged from the outlet 4B. In [Comparative Example 1], the hydrogen ion selective permeable membrane 5A was not provided, and the migratory water that had moved from the intermediate chamber 4 to the cathode chamber 3 was circulated back to the intermediate chamber 4. During this process, no air was introduced into the intermediate chamber 4. In [Comparative Example 2], the hydrogen ion selective permeable membrane 5A was provided, and the migratory water that had moved from the intermediate chamber 4 to the cathode chamber 3 was circulated back to the intermediate chamber 4. During this process, no air was introduced into the intermediate chamber 4.

[0026] In this embodiment, the electrolytic apparatus separates heavy water from the treated water through the following process. First, hydrogen ions generated in the anode chamber 2 pass through the strongly acidic first cation exchange membrane 5 and the hydrogen ion selective permeable membrane 5A to move to the intermediate chamber 4 (Figure 1). In the intermediate chamber 4, the moving hydrogen ions preferentially bind with heavy water rather than water, and move to the cathode chamber 3 via the strongly acidic second cation exchange membrane 7. The moved water is then circulated from the outlet 3B through the flow path 42 to the treated water tank 40. In addition, hydrogen is generated in the cathode chamber 3, and this hydrogen is discharged to the outside from the outlet 3A.

[0027] [Table 1]

[0028] The separation coefficients of heavy water after 5 hours are shown in [Table 1]. In [Comparative Example 2], the voltage of the electrolytic device 1 exceeded its limit due to the influence of bubbles generated in the intermediate chamber 4, and the electrolytic device 1 could not be operated for a certain period of time. From this, it can be said that it is important to introduce air into the intermediate chamber 4 to remove bubbles.

[0029] From the results in [Table 1], it was found that the separation coefficients of [Example 1] and [Example 2] were larger than those of [Comparative Example 1] at all current values. In [Example 1] and [Example 2], it was found that the separation coefficient increased as the current value increased. When a hydrogen ion selective permeable membrane 5A was placed on top of the strongly acidic first cation exchange membrane 5 ([Example 2]), it was found that the separation coefficient was larger compared to when the hydrogen ion selective permeable membrane 5A was not provided ([Example 1]). Furthermore, it was found that the electrolytic apparatus (method) of [Example 1] showed an improvement of approximately 5% in the separation capacity of heavy water compared to the electrolytic apparatus (method) of [Comparative Example 1], and the electrolytic apparatus (method) of [Example 2] showed an improvement of approximately 10% to 15% in the separation capacity of heavy water compared to the electrolytic apparatus (method) of [Comparative Example 1].

[0030] Next, the effects and advantages of the electrolytic apparatus and electrolytic method according to this embodiment will be explained.

[0031] In this embodiment, electrolysis is performed using the electrolytic device 1, and hydrogen ions are added to the heavy water flowing into the intermediate chamber 4, which is then moved to the cathode chamber 3 side, and this moved water is then returned to the intermediate chamber 4. In addition, air is introduced into the intermediate chamber 4 in the electrolytic device 1 to remove bubbles generated in the intermediate chamber. With this configuration, heavy water can be separated more efficiently from treated water containing heavy water. By using this electrolytic device 1, the separation coefficient of heavy water in the treated water increases, and the separation performance is improved. Therefore, the electrolytic device 1 and electrolysis method according to this embodiment can efficiently separate heavy water from treated water.

[0032] Furthermore, in this embodiment, the electrolytic apparatus 1 is provided with a positive electrode 6, a strongly acidic primary cation exchange membrane 5, and a hydrogen ion selective permeable membrane 5A in that order from the anode chamber 2 side, and by overlapping the strongly acidic primary cation exchange membrane 5 and the hydrogen ion selective permeable membrane 5A, heavy water can be separated from the treated water more efficiently. In addition, by arranging multiple magnets 9 and 10 in the anode chamber 2 and cathode chamber 3, the separation coefficient of heavy water in the treated water can also be increased.

[0033] Although this embodiment has been described above, it is possible to select or omit the configurations listed in the above embodiment, or to change them to other configurations as appropriate, as long as they do not deviate from the spirit of the present invention.

[0034] In this embodiment, the target of electrolysis was described as treated water containing heavy water. However, since the electrolytic apparatus and electrolytic method according to this embodiment were applicable to treated water containing heavy water, which is an isotope of light water (H2O), and were able to separate the heavy water, they can also be applied to treated water containing tritium water, which is an isotope of light water, and similar effects can be obtained. Therefore, it is expected that the amount of radioactively contaminated water can be reduced by using the electrolytic apparatus and electrolytic method according to this embodiment.

[0035] Furthermore, although this embodiment shows an example in which treated water and air are introduced into the intermediate chamber 4 from the inlet 4A and discharged from the outlet 4B, it is also possible to provide an inlet other than inlet 4A and an outlet other than outlet 4B, and to introduce and discharge treated water and air separately. [Explanation of Symbols]

[0036] 1 Electrolyzer 2 Anode Chambers 2A Inlet (first opening) 2B Outlet (second opening) 3 Cathode Chamber 3A Outlet (third opening) 3B Outlet (fourth opening) 4. Intermediate Room 4A Inlet (fifth opening) 4B Outlet (sixth opening) 4C cation exchange resin 5. Strongly acidic primary cation exchange membrane 5A Hydrogen ion selective permeable membrane 6. Positive electrode 7. Strongly acidic second cation exchange membrane 8 negative electrode 9,10 Magnetic body 20 water tanks 21,22,32,41,42,44 Channel 40 treated water tanks 43 pumps 50 constant current power supply 100 Electrolytic Treatment Systems

Claims

1. an anode chamber having a first opening and a second opening, A cathode chamber having a third opening and a fourth opening, It has a fifth opening and a sixth opening, and comprises an intermediate chamber located between the anode chamber and the cathode chamber, with an ion exchange resin filling the interior. A first cation exchange membrane and a positive electrode are provided between the anode chamber and the intermediate chamber, and a second cation exchange membrane and a negative electrode are provided between the cathode chamber and the intermediate chamber, respectively. Water is allowed to flow into the anode chamber from the first opening and discharged from the second opening. While allowing air to flow into the intermediate chamber, treated water containing heavy water is introduced into the intermediate chamber from the fifth opening, passes through the ion exchange resin, and is then discharged from the sixth opening. The water that has moved from the intermediate chamber to the cathode chamber is circulated back into the intermediate chamber, and the air that has flowed into the intermediate chamber is discharged from the intermediate chamber to remove bubbles generated in the intermediate chamber. An electrolytic device characterized by the following features.

2. A hydrogen ion selective permeable membrane is provided superimposed on the first cation exchange membrane. From the anode chamber side, the positive electrode, the first cation exchange membrane, and the hydrogen ion selective permeable membrane are arranged in that order. The electrolytic apparatus according to feature 1.

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