An electrodeionization device

Abstract

The utility model discloses a kind of electrodeionization devices, it is related to water purification equipment field, including anode plate and cathode plate, the anode plate with the cathode plate between being provided with several ion exchange units, the ion exchange unit includes the cation exchange membrane, bipolar membrane and anion exchange membrane that are sequentially spaced, the bipolar membrane includes negative membrane face and positive membrane face, the first processing chamber for removing anion is formed between the negative membrane face with the anion exchange membrane, the second processing chamber for removing cation is formed between the positive membrane face with the cation exchange membrane, raw water sequentially through the first processing chamber and the second processing chamber to form pure water. The electrodeionization device of the utility model can remove acidic gas in raw water, improve the water quality of prepared pure water.

Description

Technical Field

[0001] This utility model relates to the field of water purification equipment technology, specifically to an electro-deionization device. Background Technology

[0002] Electrodeionization (EDI) is a novel separation technology that organically combines electrodialysis and ion exchange. It involves filling the spaces between ion exchange membranes in the desalination chamber of an electrodialysis unit with ion exchange resin, and achieving deionization under the influence of an applied DC electric field. It enables deep desalination of low-concentration solutions without the need for chemical acid-base regeneration. In recent years, EDI has developed rapidly and is now used in numerous industrial sectors, including pharmaceuticals, power generation, electronics, and food, for the preparation of pure and ultrapure water.

[0003] In certain specialized applications, such as semiconductor manufacturing, ultra-trace analysis, and high-end pharmaceuticals, there are stringent requirements regarding the content of acidic gases (such as CO2) in purified water. However, in existing electro-deionization devices, acidic gases dissolve in the raw water and exist in molecular form, and these gases cannot be effectively removed. This results in purified water with excessively high acidic gas content, failing to meet the requirements for high-purity water. Utility Model Content

[0004] This invention aims to address one of the technical problems in related technologies to a certain extent. To this end, this invention provides an electro-deionization device capable of removing acidic gases from raw water and improving the quality of the resulting pure water.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: An electro-deionization device includes an anode plate and a cathode plate, with a plurality of ion exchange units disposed between the anode plate and the cathode plate. Each ion exchange unit includes a cation exchange membrane, a bipolar membrane, and an anion exchange membrane arranged in sequence at intervals. The bipolar membrane includes an anion membrane surface and a cation membrane surface. A first treatment chamber for removing anions is formed between the anion membrane surface and the anion exchange membrane, and a second treatment chamber for removing cations is formed between the cation membrane surface and the cation exchange membrane. Raw water sequentially passes through the first treatment chamber and the second treatment chamber to form pure water.

[0006] In this application, the raw water is neutral in pH. The first treatment chamber is located between the bipolar membrane and the anion exchange membrane. Under the influence of an electric field, after the raw water enters the first treatment chamber, the anions in the water are attracted by the anode plate and move towards the anode plate. The anion exchange membrane only allows anions to pass through, blocking cations, allowing the anions to pass smoothly through the anion exchange membrane and be separated from the first treatment chamber, thereby achieving anion removal. It should be noted that when the concentration of acidic gases (such as carbon dioxide) reaches a certain level, the final pure water quality may not meet the requirements of high-purity water standards. In this application, hydroxide ions are enriched in the first treatment chamber to remove carbon dioxide and other acid radicals from the raw water, improving the quality of the obtained pure water. The second treatment chamber is located between the bipolar membrane and the cation exchange membrane. After the raw water flows out of the first treatment chamber, it enters the second treatment chamber. At this time, the cations in the water are attracted by the cathode plate and move towards the cathode. The cation exchange membrane allows only cations to pass through, blocking anions. Therefore, cations can be separated from the second treatment chamber, ultimately purifying the raw water into pure water. The second treatment chamber is enriched with hydrogen ions, which reduces the formation of precipitates from the alkaline liquid flowing from the first treatment chamber by combining with metal cations, and also reduces calcium carbonate scaling. When electricity is applied to the anode and cathode plates, a cathodic reaction occurs near the cathode plate, producing hydrogen gas and hydroxide ions, thus increasing the pH value near the cathode plate. At this time, hydrogen ions are generated on the anolyte surface of the bipolar membrane under the influence of the electric field, and these hydrogen ions migrate towards the cathode plate. Therefore, hydrogen ions neutralize hydroxide ions near the cathode plate, lowering the pH value and preventing scaling caused by the precipitation of polyvalent metal cations. This also reduces the risk of scaling in the electro-deionization device and its connected pipes and water tank.

[0007] In addition, the cation exchange membrane can supply hydrogen ions to the first treatment chamber, which reduces the relative concentration of cations such as calcium and magnesium. According to the laws of ion migration, cations move towards the cathode under the influence of an electric field. The increased hydrogen ion concentration in the first treatment chamber strengthens the electric field driving force on other cations. Simultaneously, the acidic environment formed by the combination of hydrogen ions and anions helps break the binding force between cations and anions, thus promoting the faster departure of other cations from the first treatment chamber without introducing other impurity ions. This ensures the purity of the treated water and avoids potential adverse effects on subsequent processes or usage scenarios caused by the introduction of impurity ions. Similarly, the anion exchange membrane can supply hydroxide ions to the second treatment chamber to dilute other anions in the first treatment chamber, promoting their departure without introducing other impurity ions.

[0008] Optionally, the cathode plate and the cation exchange membrane are adjacent to each other and form a cathode cavity between them, and the anode plate and the anion exchange membrane are adjacent to each other and form an anode cavity between them. The anode cavity and the cathode cavity attract and remove ions only through electric field force and electrolysis reaction, without introducing other impurity ions, thus ensuring the purity of the treated water.

[0009] Optionally, the raw water flows successively through the anode chamber and the cathode chamber before being output to form a wastewater path. The wastewater is centrally discharged through this specific wastewater path, facilitating centralized wastewater treatment.

[0010] Optionally, the raw water flows through the cathode cavity and the anode cavity respectively, and then merges and exits together to form a wastewater path. By treating the wastewater separately and merging it, the composition of the wastewater is relatively clear, making it easier to select a suitable treatment method based on the characteristics of the wastewater.

[0011] Optionally, two ion exchange units are configured, arranged along the direction from the cathode plate to the anode plate and having a drainage gap, the drainage gap being filled with anion exchange resin and cation exchange resin. The two ion exchange units constitute a multi-stage treatment system, improving the efficiency of ion removal.

[0012] Optionally, the raw water flows sequentially through the anode chamber and the cathode chamber to form a first branch, and simultaneously flows through the drainage interval to form a second branch. The first and second branches converge and are then discharged together to form a wastewater path. Some ions are removed through resin adsorption in the second branch, thereby reducing pollution and scaling problems inside the device. At the same time, the acidity of the anode chamber and the alkalinity of the cathode chamber in the first branch are balanced to a certain extent, avoiding excessively high or low pH values ​​in localized areas within the device. This makes the ion exchange environment inside the device more stable, which is beneficial for the ion exchange process and improves the operational stability of the device.

[0013] Optionally, the raw water flows through the anode chamber, the cathode chamber, and the drainage interval respectively, and then converges and exits together to form a wastewater path. This multi-pathway treatment can more comprehensively remove various ions from the raw water, improving the efficiency of ion removal.

[0014] Optionally, the raw water flows sequentially through the anode chamber, the drainage interval, and the cathode chamber to form a wastewater path, and the raw water flows sequentially through two ion exchange units to form a pure water path. The two ion exchange units in the pure water path can sequentially remove ions from the water flow. Through multi-stage treatment, the efficiency of ion removal is improved, and pure water with higher purity can be obtained.

[0015] Optionally, the cation exchange membrane and the bipolar membrane are integrally disposed on top of each other, and / or the anion exchange membrane and the bipolar membrane are integrally disposed on top of each other.

[0016] Optionally, the first treatment chamber is filled with anion exchange resin, and the second treatment chamber is filled with cation exchange resin. The anion exchange resin adsorbs anions, and the cation exchange resin adsorbs cations, thereby purifying the raw water.

[0017] These features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. The preferred embodiments or means of this utility model will be shown in detail in conjunction with the accompanying drawings, but are not intended to limit the technical solutions of this utility model. In addition, each of these features, elements and components appearing in the following text and drawings is multiple and is labeled with different symbols or numbers for convenience, but all represent parts with the same or similar structure or function. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present utility model; Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the structure of Embodiment 3 of this utility model; Figure 4 This is a schematic diagram of the structure of Embodiment 4 of this utility model; Figure 5 This is a schematic diagram of the structure of Embodiment 5 of the present invention; Figure 6 This is a structural schematic diagram of Embodiment 6 of the present invention.

[0019] Among them, 1. Anode plate; 11. Anode cavity; 2. Cathode plate; 21. Cathode cavity; 3. Cation exchange membrane; 4. Anion exchange membrane; 5. Bipolar membrane; 6. First treatment chamber; 7. Second treatment chamber; 8. Drainage compartment. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described are intended to explain this utility model and should not be construed as limiting it.

[0021] The terms "an embodiment," "example," or "trademark" used in this specification refer to a particular feature, structure, or characteristic described in connection with the embodiment itself that may be included in at least one embodiment disclosed in this patent. The phrase "in an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0022] Example 1: like Figure 1 As shown, this embodiment provides an electro-deionization device, including an anode plate 1 and a cathode plate 2. A plurality of ion exchange units are disposed between the anode plate 1 and the cathode plate 2. The ion exchange units include a cation exchange membrane 3, a bipolar membrane 5 and an anion exchange membrane 4 arranged in sequence at intervals. The bipolar membrane 5 includes an anion membrane surface and a cation membrane surface. A first treatment chamber 6 for removing anions is formed between the anion membrane surface and the anion exchange membrane 4. A second treatment chamber 7 for removing cations is formed between the cation membrane surface and the cation exchange membrane 3. Raw water passes through the first treatment chamber 6 and the second treatment chamber 7 in sequence to form pure water.

[0023] In this embodiment, the electro-deionization device consists of an anode plate 1, a cathode plate 2, and several ion exchange units disposed between them. The anode plate 1 and cathode plate 2 are respectively connected to the positive and negative terminals of a DC power supply to provide a stable DC electric field to the entire device. Each ion exchange unit consists of a cation exchange membrane 3, a bipolar membrane 5, and an anion exchange membrane 4 arranged in sequence at intervals. A first treatment chamber 6 is formed between the anion membrane surface of the bipolar membrane 5 and the anion exchange membrane 4, primarily used to remove anions from the raw water. A second treatment chamber 7 is formed between the cation membrane surface of the bipolar membrane 5 and the cation exchange membrane 3, primarily used to remove cations from the raw water. When a DC electric field is applied between the anode plate 1 and the cathode plate 2, the ions in the raw water undergo directional movement under the influence of the electric field force. Cations move towards the cathode plate 2, and anions move towards the anode plate 1. After the raw water enters the first treatment chamber 6, anions are attracted by the anode plate 1 and move towards the anode. The anion exchange membrane 4 only allows anions to pass through, blocking cations, allowing anions to smoothly pass through the anion exchange membrane 4 and detach from the first treatment chamber 6. Water treated in the first treatment chamber 6 enters the second treatment chamber 7. Here, cations in the water are attracted to the cathode plate 2 and move towards the cathode. The cation exchange membrane 3 only allows cations to pass through, blocking anions, thus allowing cations to escape from the second treatment chamber 7. After treatment in the first and second treatment chambers 6, anions and cations in the raw water are removed, ultimately forming high-purity pure water. Due to the electrolysis of water and ion migration, a cathode reaction occurs near the cathode plate 2, producing hydrogen gas and hydroxide ions, leading to an increase in pH. At this time, the bipolar membrane 5 generates hydrogen ions under the influence of the electric field, and these hydrogen ions migrate towards the cathode plate 2. Therefore, hydrogen ions can neutralize excess hydroxide ions near the cathode plate 2, lowering the pH and inhibiting scale formation.

[0024] The cathode plate 2 and the cation exchange membrane 3 are adjacent to each other and form a cathode cavity 21 between them. The anode plate 1 and the anion exchange membrane 4 are adjacent to each other and form an anode cavity 11 between them.

[0025] In this embodiment, the cathode plate 2 and the cation exchange membrane 3 are arranged adjacent to each other, forming a cathode cavity 21 between them; the anode plate 1 and the anion exchange membrane 4 are arranged adjacent to each other, forming an anode cavity 11 between them. The entire device consists of several ion exchange units arranged sequentially in the middle, with the anode plate 1 and the cathode plate 2 as the two ends. Each ion exchange unit includes a cation exchange membrane 3, a bipolar membrane 5, and an anion exchange membrane 4 arranged at intervals. The anode cavity 11 and the cathode cavity 21 attract and remove ions only through electric field force and electrolysis reaction, without introducing other impurity ions, thus ensuring the purity of the treated water.

[0026] The raw water flows through the anode chamber 11 and the cathode chamber 21 before being discharged to form a wastewater channel.

[0027] In this embodiment, raw water enters through the inlet of the device and first flows into the anode chamber 11. Inside the anode chamber 11, the raw water is affected by the electric field and the electrolytic reaction occurring on the surface of the anode plate 1, and anions in the first treatment chamber 6 begin to migrate into the raw water in the anode chamber 11. Subsequently, the water carrying anions from the first treatment chamber 6 flows out of the anode chamber 11 and into the cathode chamber 21. Similarly, in the cathode chamber 21, the raw water continues to be affected by the electric field and the electrolytic reaction of the cathode plate 2, continuing to carry away cations from the second treatment chamber 7. Finally, the high-concentration ionized water treated by the anode chamber 11 and cathode chamber 21 is discharged as wastewater from the wastewater outlet of the device. Due to the electrolysis of water by the anode plate 1, there is an excess of hydrogen ions in the anode cavity 11, so the liquid in the anode cavity 11 is acidic. Due to the electrolysis of water by the cathode plate 2, there is an excess of hydroxide ions in the cathode cavity 21, so the liquid in the cathode cavity 21 is alkaline. However, after the liquid in the anode cavity 11 is injected into the cathode cavity 21, the liquid in the cathode cavity 21 becomes neutral as a whole.

[0028] The first treatment chamber 6 is filled with anion exchange resin, and the second treatment chamber 7 is filled with cation exchange resin.

[0029] In this embodiment, the anion exchange resin adsorbs anions, and the cation exchange resin adsorbs cations, thereby purifying the raw water. The anions adsorbed by the anion exchange resin migrate towards the anode in the electric field and leave the first treatment chamber 6 through the anion exchange membrane 4, whereby the resin is reverted to the hydroxide form. The cations adsorbed by the cation exchange resin migrate towards the cathode in the electric field and leave the second treatment chamber 7 through the cation exchange membrane 3, whereby the resin is reverted to the hydrogen ion form. Furthermore, under a high-voltage electric field, water molecules ionize on the resin surface, and hydroxide and hydrogen ions directly replenish the active groups of the resin, achieving dynamic regeneration.

[0030] Example 2: like Figure 2 As shown, in this embodiment, the structure of the electro-deionization device is roughly the same as that in Embodiment 1, except that the raw water flows through the cathode cavity 21 and the anode cavity 11 respectively and is then output together to form a wastewater path.

[0031] After entering the device, the raw water is designed to flow separately into the cathode chamber 21 and the anode chamber 11, undergoing different ionization processes in each chamber before converging and being discharged together to form the wastewater path. Specifically, after entering the device through the inlet, the raw water is divided into two streams by a diversion device. One stream flows into the cathode chamber 21, and the other into the anode chamber 11. The raw water flowing into the cathode chamber 21 carries cations from the second treatment chamber 7, while the raw water flowing into the anode chamber 11 carries anions from the first treatment chamber 6. The two streams then converge and are finally discharged from the device through the wastewater outlet. Due to the electrolysis of water by the anode plate 1, there is an excess of hydrogen ions in the anode chamber 11, making the liquid in the anode chamber 11 acidic. Due to the electrolysis of water by the cathode plate 2, there is an excess of hydroxide ions in the cathode chamber 21, making the liquid in the cathode chamber 21 alkaline. After the two streams converge, the overall state is neutral.

[0032] Example 3: like Figure 3 As shown, the structure in this embodiment is roughly the same as that in embodiment 1, except that: there are two ion exchange units, which are arranged along the direction from cathode plate 2 to anode plate 1 and have a drainage interval 8. The drainage interval 8 is filled with anion exchange resin and cation exchange resin.

[0033] Two ion exchange units constitute a multi-stage processing system, improving the efficiency of ion removal. In other embodiments, the ion exchange units can also be configured to be three, four, or more.

[0034] The raw water flows through the anode chamber 11 and the cathode chamber 21 to form the first branch, and at the same time, the raw water flows through the drainage interval 8 to form the second branch. The first and second branches merge and are discharged together to form the wastewater channel.

[0035] After entering the device through the inlet, the raw water first flows into the anode chamber 11. Inside the anode chamber 11, the raw water is affected by the electric field and the electrolytic reaction occurring on the surface of the anode plate 1, and anions in the first treatment chamber 6 begin to migrate into the raw water in the anode chamber 11. Then, the water carrying the anions from the first treatment chamber 6 flows out of the anode chamber 11 and into the cathode chamber 21. Similarly, in the cathode chamber 21, the raw water continues to be affected by the electric field and the electrolytic reaction of the cathode plate 2, continuing to carry away cations from the second treatment chamber 7. This water flow path through the anode chamber 11 and the cathode chamber 21 constitutes the first branch. The liquid in the anode chamber 11 is acidic, and the liquid in the cathode chamber 21 is alkaline; therefore, the liquid flowing out of the first branch is generally neutral. Another portion of the raw water flows directly into the drainage interval 8. Inside the drainage interval 8, the filled anion exchange resin and cation exchange resin adsorb and exchange anions and cations in the raw water, removing some ions. This water flow path through the drainage interval 8 constitutes the second branch. The water flows from the first and second branches converge and then exit through the wastewater outlet, forming a wastewater path. This multi-pathway treatment more comprehensively removes various ions from the raw water, improving ion removal efficiency. The wastewater flowing out of the second branch is neutral, and the wastewater flowing out of the first branch is also neutral; therefore, the wastewater in this path is neutral.

[0036] Example 4: like Figure 4 As shown, the structure in this embodiment is roughly the same as that in embodiment 3, except that the raw water flows through the anode chamber 11, the cathode chamber 21 and the drainage interval 8 respectively and then flows together to form a wastewater channel.

[0037] After entering the device through the inlet, the raw water is divided into three streams. One stream flows into the anode chamber 11, one into the cathode chamber 21, and the other into the drainage interval 8. These three streams undergo different treatment processes within the anode chamber 11, cathode chamber 21, and drainage interval 8, respectively, before flowing out of their respective chambers or intervals. They converge in the confluence area inside the device and then exit through the wastewater outlet, forming a wastewater path. As described above, the water flowing out of the anode chamber 11 is acidic, the liquid flowing out of the cathode chamber 21 is alkaline, and the water flowing out of the drainage interval 8 is neutral. Therefore, the combined water from the three streams is neutral.

[0038] Example 5: like Figure 5 As shown, the structure in this embodiment is roughly the same as that in embodiment 3, except that the raw water flows through the anode chamber 11, the drainage interval 8 and the cathode chamber 21 in sequence to form a wastewater water path, and the raw water flows through two ion exchange units in sequence to form a pure water water path.

[0039] After entering the device through the inlet, the raw water first flows into the anode chamber 11. Inside the anode chamber 11, the raw water is affected by the electric field and the electrolytic reaction occurring on the surface of the anode plate 1, and the anions in the first treatment chamber 6 begin to migrate into the raw water in the anode chamber 11. Then, the water carrying the anions from the first treatment chamber 6 flows out of the anode chamber 11 and into the drainage interval 8, finally entering the cathode chamber 21. The raw water continues to be affected by the electric field and the electrolytic reaction of the cathode plate 2, further carrying away the cations from the second treatment chamber 7. The two ion exchange units in the pure water circuit can sequentially remove ions from the water flow. Through multi-stage treatment, the efficiency of ion removal is improved, resulting in pure water with higher purity.

[0040] Example 6: like Figure 6 As shown, the structure in this embodiment is roughly the same as that in embodiment 5, except that the raw water flows through two ion exchange units and converges to form a pure water path, which can purify more raw water at the same time and improve the efficiency of ion removal.

[0041] Example 7: The difference between this embodiment and embodiment 1 is that the cation exchange membrane 3 and the bipolar membrane 5 are integrally arranged vertically, and / or the anion exchange membrane 4 and the bipolar membrane 5 are integrally arranged vertically.

[0042] An integrated membrane structure can replace multiple independent membrane modules in the traditional system, reducing the number of membrane modules in the device, simplifying the device structure, reducing the manufacturing cost and maintenance difficulty, and allowing the device to occupy less space with the same processing capacity, which is conducive to the integration and miniaturization of the equipment.

[0043] The above are merely specific embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Those skilled in the art should understand that this utility model includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this utility model will be included within the scope of the claims.

Claims

1. An electro-deionization device, comprising an anode plate (1) and a cathode plate (2), wherein a plurality of ion exchange units are disposed between the anode plate (1) and the cathode plate (2), characterized in that, The ion exchange unit includes a cation exchange membrane (3), a bipolar membrane (5), and an anion exchange membrane (4) arranged in sequence at intervals. The bipolar membrane (5) includes an anion membrane surface and a cation membrane surface. A first treatment chamber (6) for removing anions is formed between the anion membrane surface and the anion exchange membrane (4). A second treatment chamber (7) for removing cations is formed between the cation membrane surface and the cation exchange membrane (3). Raw water passes through the first treatment chamber (6) and the second treatment chamber (7) in sequence to form pure water.

2. The electro-deionization device according to claim 1, characterized in that, The cathode plate (2) and the cation exchange membrane (3) are adjacent to each other and form a cathode cavity (21) between them, and the anode plate (1) and the anion exchange membrane (4) are adjacent to each other and form an anode cavity (11) between them.

3. The electro-deionization device according to claim 2, characterized in that, The raw water flows through the anode chamber (11) and the cathode chamber (21) before being output to form a wastewater channel.

4. The electro-deionization device according to claim 2, characterized in that, The raw water flows through the cathode cavity (21) and the anode cavity (11) respectively, and then flows together to form a wastewater channel.

5. The electro-deionization device according to claim 2, characterized in that, The ion exchange unit is configured as two units, which are arranged along the direction from the cathode plate (2) to the anode plate (1) and have a drainage interval (8), which is filled with anion exchange resin and cation exchange resin.

6. The electro-deionization apparatus according to claim 5, characterized in that, The raw water flows through the anode chamber (11) and the cathode chamber (21) to form the first branch, and at the same time, the raw water flows through the drainage interval (8) to form the second branch. The first branch and the second branch merge and are then discharged together to form the wastewater channel.

7. The electro-deionization apparatus according to claim 5, characterized in that, The raw water flows through the anode chamber (11), the cathode chamber (21), and the drainage interval (8) respectively, and is then discharged together to form a wastewater channel.

8. The electro-deionization apparatus according to claim 5, characterized in that, The raw water flows successively through the anode chamber (11), the drainage interval (8), and the cathode chamber (21) to form a wastewater path, and the raw water flows successively through two ion exchange units to form a pure water path.

9. The electro-deionization device according to claim 1, characterized in that, The cation exchange membrane (3) and the bipolar membrane (5) are integrally disposed on the top and bottom, and / or the anion exchange membrane (4) and the bipolar membrane (5) are integrally disposed on the top and bottom.

10. The electro-deionization device according to claim 1, characterized in that, The first processing chamber (6) is filled with anion exchange resin, and the second processing chamber (7) is filled with cation exchange resin.

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