Target ion separation device and method based on electric salt leaching configuration

Abstract

The invention discloses a target ion separation device and method based on an electric salt leaching configuration, and particularly belongs to the technical field of membrane separation. The device comprises a first pole chamber, a first standard ion exchange membrane adjacent to the first pole chamber and a second pole chamber, the polarities of electrodes in the first pole chamber and the second pole chamber are opposite; at least one unit membrane stack is arranged between the first standard ion exchange membrane and the second pole chamber; each unit membrane stack comprises a storage chamber, a second standard ion exchange membrane, a feed liquid cavity, a selective membrane, a receiving chamber and a third standard ion exchange membrane which are arranged in sequence. The device can strengthen selective separation through an arrangement mode of the membranes, has very strong process flexibility, can adjust configuration parameters according to impurity compositions of different salt solutions, realizes efficient separation and high-concentration collection of target ions, and is suitable for high-purity salt production requirements of multiple industries.

Description

Technical Field

[0001] This application relates to the field of membrane separation technology, and in particular to a target ion separation device and method based on an electrowashed salt configuration. Background Technology

[0002] With industrial development and population growth, the demand for high-purity salts (such as food-grade, pharmaceutical-grade, or electronic-grade salts) is increasing. Traditional salt purification methods mainly include recrystallization, chemical precipitation, and evaporation concentration, but these methods typically suffer from high energy consumption, complex processes, limited product purity, or the generation of large amounts of waste liquid. For example, recrystallization requires multiple dissolution and crystallization processes, which is not only inefficient but may also introduce new impurities; chemical precipitation relies on the addition of reagents, which may affect the final quality of the salt and increase subsequent processing costs.

[0003] Electrodialysis, a mature membrane separation technology, separates ions by driving them through an ion exchange membrane using an electric field. It has been widely applied in water treatment, food processing, and chemical purification. However, traditional electrodialysis devices employ a conventional configuration of "electrode chamber - ion exchange membrane - desalination chamber - ion exchange membrane - concentration chamber - electrode chamber." However, traditional electrodialysis devices suffer from insufficient membrane selectivity; ordinary ion exchange membranes are less effective against multivalent ions (such as SO42-). 2- Ca 2+ Mg 2+ (etc.) and monovalent ions (Cl) - Na + NO3 - The separation of ions, whether single or multiple ions, is limited, making it difficult to achieve high-purity preparation. This often necessitates multi-stage processing or integration with other purification processes, increasing system complexity. Furthermore, traditional electrodialysis devices employ fixed membrane stack arrangements, making it difficult to flexibly control the migration paths of different ions, thus affecting purification efficiency and failing to meet the high-purity salt production needs of various industries. Therefore, there is an urgent need to develop a target ion separation device and method based on electrowashing salt configuration to solve these problems. Summary of the Invention

[0004] In view of this, this application provides a target ion separation device and method based on electrowashing salt configuration, which can enhance selective separation through membrane arrangement and has strong process flexibility. The configuration parameters can be adjusted according to the impurity composition of different salt solutions to achieve efficient separation and high-concentration collection of target ions, and is suitable for the high-purity salt production needs of multiple industries.

[0005] Specifically, the following technical solutions are included:

[0006] In a first aspect, this application provides a target ion separation device based on an electrowashed salt configuration, the device comprising: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber;

[0007] The electrodes in the first and second polarity chambers have opposite polarities;

[0008] At least one unit membrane stack is provided between the first standard ion exchange membrane and the second electrode chamber;

[0009] The unit membrane stack comprises, in sequence, a reservoir chamber, a second standard ion exchange membrane, a feed chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane. The first and second standard ion exchange membranes are ion exchange membranes with opposite charges; the second standard ion exchange membrane and the selective membrane have the same charge; and the first and third standard ion exchange membranes have the same charge. This arrangement guides the retained ions in the reservoir chamber into the feed chamber, where the retained ions are those retained by the selective membrane. The selective membrane uses a membrane material with specific permeability to the target ions, allowing only the target ions to pass through while retaining other impurity ions, thus ensuring the purity of the target ions in the receiving chamber.

[0010] The electrodes in the first and second electrode chambers have opposite polarities. The first and second standard ion exchange membranes are ion exchange membranes with opposite charges. The second standard ion exchange membrane and the selective membrane have the same charge. The first and third standard ion exchange membranes also have the same charge. Selection can be made based on the charge of the target ion to be separated, optimizing the membrane stack arrangement. Combined with the selective membrane, a synergistic separation mechanism can be constructed to improve the separation efficiency and purity of the target ion.

[0011] In some embodiments, the electrode solutions in the first and second electrode chambers are sodium sulfate or sodium chloride solutions with a concentration of 0.3–0.5 mol / L. Electrodes are built into the first and second electrode chambers; the introduction of the electrode solution maintains a stable electric field and prevents electrode polarization.

[0012] In some embodiments, when the target ion is a cation, the built-in electrode in the first electrode chamber is an anode and the first standard ion exchange membrane is an anion membrane;

[0013] When the target ion is an anion, the built-in electrode in the first electrode chamber is the cathode, and the first standard ion exchange membrane is the cation membrane.

[0014] In some embodiments, a solution corresponding to the ions retained by the selective membrane is introduced into the reservoir, and the concentration of the solution corresponding to the ions retained by the selective membrane is 0.5~3 mol / L. As a "reservoir" of retained ions, the selective membrane continuously replenishes the feed chamber with retained ions.

[0015] In some embodiments, the feed chamber is circulated with a solution to be separated. The solution to be separated is a solution of the target ions to be separated. The feed chamber is the core region where the retained ions and target ions exchange. Sufficient ion exchange can be ensured by adjusting the concentration in the reservoir or the volume ratio of the reservoir to the solution in the feed chamber.

[0016] In some embodiments, a target ion solution with a concentration of 0.01~0.1 mol / L is introduced into the receiving chamber. The receiving chamber provides the "driving force" for the migration of target ions, ultimately enriching them at a high concentration.

[0017] In some embodiments, the inlet flow rate of the first electrode chamber, the second electrode chamber, the reservoir chamber, the feed chamber, and the receiving chamber is 10~35L / h to ensure stable solution flow.

[0018] In some embodiments, the current density of the constant current applied to the electrodes of the first and second electrode chambers is 50~200 A / m. 2 Under the influence of an electric field, the retained ions in the storage chamber migrate through the standard ion exchange membrane into the feed chamber via electromigration, replacing the target ions in the feed chamber. The target ions that are replaced in the feed chamber are then driven by the electric field to pass through the selective membrane into the receiving chamber. Once the concentration of the target ions in the receiving chamber has basically stabilized, the operation can be stopped, and the receiving chamber will contain a high-concentration, high-purity target ion solution.

[0019] Secondly, this application provides a target ion separation method based on an electrowashed salt configuration, the separation method being used in the target ion separation apparatus based on an electrowashed salt configuration described in the first aspect, the separation method comprising:

[0020] Step 1: Introduce sodium sulfate solution or sodium chloride solution into the first and second electrode chambers, introduce a solution corresponding to the ions retained by the selective membrane into the storage chamber, introduce the liquid to be separated into the feed chamber, and introduce the target ion solution into the receiving chamber, while controlling the inlet flow rates of the first electrode chamber, second electrode chamber, storage chamber, feed chamber, and receiving chamber.

[0021] Step 2: Turn on the electrode power supply and apply a constant current to the electrodes of the first and second electrode chambers;

[0022] Step 3: Once the target ions are enriched in the receiving chamber and the target ion concentration is stable, collect the target ion solution.

[0023] Other specific point values ​​within the above numerical ranges can be selected, all of which are within the protection scope of this invention. Due to space limitations, they will not be described in detail here.

[0024] The beneficial effects of the technical solutions provided in this application include at least the following:

[0025] This application provides a target ion separation device and method based on an electrowashed salt configuration. The device includes: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber; the electrodes in the first and second electrode chambers have opposite polarities; at least one unit membrane stack is disposed between the first standard ion exchange membrane and the second electrode chamber; the unit membrane stack includes a reservoir chamber, a second standard ion exchange membrane, a feed liquid chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane arranged sequentially, wherein the first and second standard ion exchange membranes are ion exchange membranes with opposite charges, the second standard ion exchange membrane and the selective membrane have the same charge, and the first and third standard ion exchange membranes have the same charge. This device can enhance selective separation through membrane arrangement and also has strong process flexibility, allowing adjustment of configuration parameters according to the impurity composition of different salt solutions to achieve efficient separation and high-concentration collection of target ions, applicable to the high-purity salt production needs of multiple industries. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the target cation separation device with a single-unit membrane stack electrowashing salt configuration.

[0028] Figure 2 This is a schematic diagram of a target anion separation device with a single-unit membrane stack electrowashing salt configuration.

[0029] Figure 3 This is a schematic diagram of a target cation separation device with a multi-unit membrane stack electrowashing salt configuration.

[0030] Figure 4 This is a schematic diagram of a target anion separation device with a multi-unit membrane stack electrowashing salt configuration.

[0031] Figure 5 This is a schematic diagram of a multi-unit conventional electrodialysis target cation separation device.

[0032] Figure 6 This is a schematic diagram of a multi-unit conventional electrodialysis target anion separation device.

[0033] Figure 7 This is a schematic diagram of a single-unit conventional electrodialysis target anion separation device.

[0034] Figure 8 Li in the receiving chamber of Example 3 and Comparative Example 1 + Concentration and Li + Mg 2+ Comparison of ion migration rates through selective membranes.

[0035] Figure 9 Cl in the receiving chamber of Example 4 and Comparative Example 2 - Concentration and Cl - SO4 2- Comparison of ion migration rates through selective membranes.

[0036] Figure 10 NO3 in the receiving chamber of Example 2 and Comparative Example 3 - Concentration and Cl - NO3 - Comparison of ion migration rates through selective membranes. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] To make the technical solutions and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0039] Example 1: Single-unit membrane stack electrowashing salt configuration target cation separation device

[0040] like Figure 1 As shown, the device includes: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber;

[0041] The first electrode chamber contains the anode, and the second electrode chamber contains the cathode.

[0042] A unit membrane stack is provided between the first standard ion exchange membrane and the second electrode chamber;

[0043] The unit membrane stack includes a storage chamber, a second standard ion exchange membrane, a feed liquid chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane arranged sequentially. The first standard ion exchange membrane is an anion membrane, the second standard ion exchange membrane is a cation membrane, the selective membrane is a cation membrane, and the third standard ion exchange membrane is an anion membrane.

[0044] In some embodiments, the electrode solutions in the first and second electrode chambers are sodium sulfate solutions or sodium chloride solutions, and the electrode solution concentration is 0.3~0.5 mol / L, for example, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, or 0.5 mol / L.

[0045] In some embodiments, a solution corresponding to the ions retained by the selective membrane is introduced into the storage chamber. The concentration of the solution corresponding to the ions retained by the selective membrane is 0.5~3 mol / L, for example, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or 3 mol / L.

[0046] In some embodiments, the feed chamber is circulated with the liquid to be separated. The liquid to be separated is a solution of the target ions to be separated.

[0047] In some embodiments, a target ion solution is introduced into the receiving chamber, and the concentration of the target ion solution is 0.01~0.1 mol / L, for example, 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.07 mol / L, or 0.1 mol / L.

[0048] In some embodiments, the inlet flow rate of the first electrode chamber, the second electrode chamber, the storage chamber, the feed liquid chamber, and the receiving chamber is 10~35L / h, for example, 10L / h, 15L / h, 20L / h, 25L / h, 30L / h, or 35L / h.

[0049] In some embodiments, the current density of the constant current applied to the electrodes of the first and second electrode chambers is 50~200 A / m. 2 For example, 50A / m 2 800A / m 2 100A / m 2 150A / m 2 200A / m 2 .

[0050] Example 2: Single-unit membrane stack electrowashing salt configuration target anion separation device and its application in separating (purifying) nitrate ions in simulated seawater.

[0051] like Figure 2 As shown, the device includes: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber;

[0052] The first electrode chamber contains a cathode, and the second electrode chamber contains an anode.

[0053] A unit membrane stack is provided between the first standard ion exchange membrane and the second electrode chamber;

[0054] The unit membrane stack includes a storage chamber, a second standard ion exchange membrane, a feed liquid chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane arranged sequentially. The first standard ion exchange membrane is a cation membrane, the second standard ion exchange membrane is an anion membrane, the selective membrane is an anion membrane, and the third standard ion exchange membrane is a cation membrane.

[0055] In some embodiments, the electrode solutions in the first and second electrode chambers are sodium sulfate solutions or sodium chloride solutions, and the electrode solution concentration is 0.3~0.5 mol / L, for example, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, or 0.5 mol / L.

[0056] In some embodiments, a solution corresponding to the ions retained by the selective membrane is introduced into the storage chamber. The concentration of the solution corresponding to the ions retained by the selective membrane is 0.5~3 mol / L, for example, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or 3 mol / L. In some embodiments, a solution to be separated is introduced into the feed chamber. The solution to be separated is a solution of the target ions to be separated.

[0057] In some embodiments, a target ion solution is introduced into the receiving chamber, and the concentration of the target ion solution is 0.01~0.1 mol / L, for example, 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.07 mol / L, or 0.1 mol / L.

[0058] In some embodiments, the inlet flow rate of the first electrode chamber, the second electrode chamber, the storage chamber, the feed liquid chamber, and the receiving chamber is 10~35L / h, for example, 10L / h, 15L / h, 20L / h, 25L / h, 30L / h, or 35L / h.

[0059] In some embodiments, the current density of the constant current applied to the electrodes of the first and second electrode chambers is 50~200 A / m. 2 For example, 50A / m 2 800A / m 2 100A / m 2 150A / m 2 200A / m 2 .

[0060] A single-unit membrane stack electrowashing salt configuration target anion separation device was used to separate nitrate ions from simulated seawater. See the schematic diagram of the device. Figure 2 The device consists of two standard cation exchange membranes (i.e., the cation membrane in the figure), one standard anion exchange membrane (i.e., the anion membrane in the figure), and one Cl- membrane. - / NO3 -The apparatus consists of a selective membrane, a reservoir chamber, a feed chamber, a receiving chamber, and two polar chambers (a first polar chamber and a second polar chamber). Before the experiment, 0.3 mol / L Na₂SO₄ solution, 2 mol / L NaCl solution, a mixed solution of 0.5 mol / L NaCl and 0.02 mol / L NaNO₃, and a 0.01 mol / L NaNO₃ solution are respectively introduced into the polar chambers (including the first and second polar chambers), the reservoir chamber, the feed chamber, and the receiving chamber, at a flow rate of 10 L / h. A 50 A / m² pressure is applied to both sides of the apparatus. 2 and 200A / m 2 The current density of a constant current (it should be noted that the current density of a constant current is 50 A / m) 2 At that time, the current density applied to the electrodes of the first and second electrode chambers of the device was 50 A / m. 2 A constant current; the current density of the constant current is 200 A / m. 2 At that time, the current density applied to the electrodes of the first and second electrode chambers of the device was 200 A / m. 2 A constant current), under the influence of an electric field, Cl in the storage chamber... - (Retained ions) migrate through the standard anion exchange membrane into the feed chamber via electromigration, removing NO3 from the feed chamber. - (Target ion) replacement, actively "driving" NO3 - Under the influence of an electric field, it passes through the selective anion exchange membrane and enters the receiving chamber, where NO3- is awaiting collection. - Operation was stopped after the concentration stabilized. During the experiment, NO3 in the receiving chamber... - Concentration and Cl - NO3 - The rate of migration across the selective membrane, such as Figure 10 As shown.

[0061] Example 3: Multi-unit membrane stack electrowashing salt configuration target cation separation device and its application in separating lithium ions in simulated salt lake brine.

[0062] like Figure 3 As shown, the device includes: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber;

[0063] The first electrode chamber contains an anode, and the second electrode chamber contains a cathode.

[0064] Multiple unit membrane stacks are provided between the first standard ion exchange membrane and the second electrode chamber;

[0065] The unit membrane stack includes a storage chamber, a second standard ion exchange membrane, a feed liquid chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane arranged sequentially. The first standard ion exchange membrane is an anion membrane, the second standard ion exchange membrane is a cation membrane, the selective membrane is a cation membrane, and the third standard ion exchange membrane is an anion membrane.

[0066] In some embodiments, the electrode solutions in the first and second electrode chambers are sodium sulfate solutions or sodium chloride solutions, and the electrode solution concentration is 0.3~0.5 mol / L, for example, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, or 0.5 mol / L.

[0067] In some embodiments, a solution corresponding to the ions retained by the selective membrane is introduced into the storage chamber. The concentration of the solution corresponding to the ions retained by the selective membrane is 0.5~3 mol / L, for example, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or 3 mol / L. In some embodiments, a solution to be separated is introduced into the feed chamber. The solution to be separated is a solution of the target ions to be separated.

[0068] In some embodiments, a target ion solution is introduced into the receiving chamber, and the concentration of the target ion solution is 0.01~0.1 mol / L, for example, 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.07 mol / L, or 0.1 mol / L.

[0069] In some embodiments, the inlet flow rate of the first electrode chamber, the second electrode chamber, the storage chamber, the feed liquid chamber, and the receiving chamber is 10~35L / h, for example, 10L / h, 15L / h, 20L / h, 25L / h, 30L / h, or 35L / h.

[0070] In some embodiments, the current density of the constant current applied to the electrodes of the first and second electrode chambers is 50~200 A / m. 2 For example, 50A / m 2 800A / m 2 100A / m 2 150A / m 2 200A / m 2 .

[0071] A multi-unit membrane stack electrowashing salt separation device comprising ten unit membrane stacks was used to separate lithium ions in simulated salt lake brine. See the schematic diagram of the device. Figure 3The apparatus consists of 11 standard anion exchange membranes (i.e., anion membranes in the figure), 10 standard cation exchange membranes (i.e., cation membranes in the figure), 10 monovalent and divalent cation selective membranes, 10 reservoir chambers, 10 feed chambers, 10 receiving chambers, and 2 polar chambers (first and second polar chambers). During the experiment, corresponding solutions are introduced into the same chambers in parallel. Before the experiment, 0.3 mol / L Na₂SO₄ solution, 0.5 mol / L MgCl₂ solution, a mixed solution of 0.25 mol / L MgCl₂ and 0.015 mol / L LiCl, and 0.01 mol / L LiCl solution were introduced into the polar chambers (first and second polar chambers), reservoir chambers, feed chambers, and receiving chambers, respectively, at a flow rate of 20 L / h. A 50 A / m² pressure was applied to both sides of the apparatus. 2 and 200A / m 2 A constant current with a constant current density, under the influence of an electric field, causes Mg in the storage chamber to... 2+ (Retained ions) migrate through the standard cation exchange membrane into the feed chamber via electromigration, removing Li from the feed chamber. + (Target ion) substitution, actively "driving" Li + Under the influence of an electric field, it passes through a selective cation exchange membrane (for monovalent and divalent cations) and enters the receiving chamber, where Li... + Operation was stopped after the concentration stabilized. During the experiment, the Li in the receiving chamber... + Concentration and Li + Mg 2+ Ion migration rate through selective membranes, such as Figure 8 As shown.

[0072] Example 4: Multi-unit membrane stack electrowashing salt configuration target anion separation device and its application in separating chloride and sulfate ions

[0073] like Figure 4 As shown, the device includes: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber;

[0074] The first electrode chamber contains a cathode, and the second electrode chamber contains an anode.

[0075] Multiple unit membrane stacks are provided between the first standard ion exchange membrane and the second electrode chamber;

[0076] The unit membrane stack includes a storage chamber, a second standard ion exchange membrane, a feed liquid chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane arranged sequentially. The first standard ion exchange membrane is a cation membrane, the second standard ion exchange membrane is an anion membrane, the selective membrane is an anion membrane, and the third standard ion exchange membrane is a cation membrane.

[0077] In some embodiments, the electrode solutions in the first and second electrode chambers are sodium sulfate solutions or sodium chloride solutions, and the electrode solution concentration is 0.3~0.5 mol / L, for example, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, or 0.5 mol / L.

[0078] In some embodiments, a solution corresponding to the ions retained by the selective membrane is introduced into the storage chamber. The concentration of the solution corresponding to the ions retained by the selective membrane is 0.5~3 mol / L, for example, 0.5 mol / L, 1 mol / L, 1.5 mol / L, 2 mol / L, or 3 mol / L.

[0079] In some embodiments, the feed chamber is circulated with the liquid to be separated. The liquid to be separated is a solution of the target ions to be separated.

[0080] In some embodiments, a target ion solution is introduced into the receiving chamber, and the concentration of the target ion solution is 0.01~0.1 mol / L, for example, 0.01 mol / L, 0.03 mol / L, 0.05 mol / L, 0.07 mol / L, or 0.1 mol / L.

[0081] In some embodiments, the inlet flow rate of the first electrode chamber, the second electrode chamber, the storage chamber, the feed liquid chamber, and the receiving chamber is 10~35L / h, for example, 10L / h, 15L / h, 20L / h, 25L / h, 30L / h, or 35L / h.

[0082] In some embodiments, the current density of the constant current applied to the electrodes of the first and second electrode chambers is 50~200 A / m. 2 For example, 50A / m 2 800A / m 2 100A / m 2 150A / m 2 200A / m 2 .

[0083] A multi-unit membrane stack electrowashing salt separation device with ten unit membrane stacks is used to separate chloride ions in a mixed solution of sodium sulfate and sodium chloride. See the schematic diagram of the device. Figure 4The apparatus consists of 11 standard cation exchange membranes, 10 standard anion exchange membranes, 10 monovalent and divalent anion selective membranes, 10 reservoir chambers, 10 feed chambers, 10 receiving chambers, and 2 electrode chambers. During the experiment, solutions are introduced into identical chambers in parallel. Before the experiment, 0.5 mol / L Na₂SO₄ solution, 1 mol / L Na₂SO₄ solution, a mixed solution of 0.5 mol / L Na₂SO₄ and 0.5 mol / L NaCl, and 0.1 mol / L NaCl solution were introduced into the electrode chambers, reservoir chambers, feed chambers, and receiving chambers, respectively, at a flow rate of 35 L / h. A 50 A / m² pressure was applied to both sides of the apparatus. 2 and 200A / m 2 A constant current with a constant current density, under the influence of an electric field, causes SO4 in the storage chamber to... 2- (Retained ions) migrate through the standard anion exchange membrane into the feed chamber via electromigration, removing Cl from the feed chamber. - (Target ion) substitution, actively "driving" Cl - Under the influence of an electric field, it passes through the selective exchange membrane for monovalent and divalent anions and enters the receiving chamber, where Cl- is received. - Operation was stopped after the concentration stabilized. During the experiment, Cl in the receiving chamber... - Concentration and Cl - SO4 2- The rate of migration across the selective membrane, such as Figure 9 As shown.

[0084] Comparative Example 1: Separation of lithium ions in simulated salt lake brine using a multi-unit conventional electrodialysis configuration target cation separation device.

[0085] Multi-unit conventional electrodialysis target cation separation device, such as Figure 5 As shown, this device separates lithium ions from simulated salt lake brine. The device consists of 11 standard anion exchange membranes, 10 monovalent and divalent cation selective membranes, 10 feed chambers, 10 receiving chambers, and 2 electrode chambers. During the experiment, solutions are introduced into identical chambers in parallel. Before the experiment, 0.3 mol / L Na₂SO₄ solution, a mixed solution of 0.25 mol / L MgCl₂ and 0.015 mol / L LiCl, and a 0.01 mol / L LiCl solution were introduced into the electrode chambers, feed chambers, and receiving chambers, respectively, at a flow rate of 20 L / h. A 50 A / m² pressure was applied to both sides of the device. 2 and 200A / m 2 Under the influence of an electric field, a constant current with high current density allows cations to migrate through a monovalent and divalent cation-selective membrane into the receiving chamber via electromigration, where they await the arrival of Li in the receiving chamber. + Operation was stopped after the concentration stabilized. During the experiment, the Li in the receiving chamber... + Concentration and Li+ Mg 2+ Ion migration rate through selective membranes, such as Figure 8 As shown, compared to Embodiment 3 of this application.

[0086] Comparative Example 2: Separation of chloride and sulfate ions by a multi-unit conventional electrodialysis target anion separator.

[0087] A multi-unit conventional electrodialysis target cation separation device with ten units is used to separate chloride ions in a mixed solution of sodium sulfate and sodium chloride. See the schematic diagram of the device. Figure 6 The apparatus consists of 11 standard cation exchange membranes, 10 monovalent and divalent anion-selective membranes, 10 feed chambers, 10 receiving chambers, and 2 electrode chambers. During the experiment, solutions are introduced into identical chambers in parallel. Before the experiment, 0.5 mol / L Na₂SO₄ solution, a mixed solution of 0.5 mol / L Na₂SO₄ and 0.5 mol / L NaCl, and a 0.1 mol / L NaCl solution were introduced into the electrode chambers, feed chambers, and receiving chambers, respectively, at a flow rate of 35 L / h. A 50 A / m² pressure was applied to both sides of the apparatus. 2 and 200A / m 2 Under the influence of an electric field, a constant current with high current density allows cations to migrate through a selective membrane containing monovalent and divalent anions into the receiving chamber, where Cl-... - Operation was stopped after the concentration stabilized. During the experiment, Cl in the receiving chamber... - Concentration and Cl - SO4 2- The rate of migration across the selective membrane, such as Figure 9 As shown, compared to Embodiment 4 of this application.

[0088] Comparative Example 3: Separation of nitrate ions from simulated seawater using a single-unit conventional electrodialysis target anion separation device.

[0089] A single-unit conventional electrodialysis target anion separation device was used to separate nitrate ions from simulated seawater. See the schematic diagram of the device. Figure 7 The device consists of one standard cation exchange membrane and one Cl- membrane. - / NO3 - The apparatus consists of a selective membrane, a feed chamber, a receiving chamber, and two electrode chambers. Before the experiment, 0.3 mol / L Na₂SO₄ solution, a mixed solution of 0.5 mol / L NaCl and 0.02 mol / L NaNO₃, and a 0.01 mol / L NaNO₃ solution were introduced into the electrode chamber, feed chamber, and receiving chamber, respectively, at a flow rate of 10 L / h. A 50 A / m² pressure was applied to both sides of the apparatus. 2 and 200A / m 2Under the influence of an electric field, a constant current with high current density causes cations to migrate through a selective anion exchange membrane into the receiving chamber, where they are received by NO3-. - Operation was stopped after the concentration stabilized. During the experiment, NO3 in the receiving chamber... - Concentration and Cl - NO3 - The rate of migration across the selective membrane, such as Figure 10 As shown, compared to Embodiment 2 of this application.

[0090] See Figure 8 , Figure 9 and Figure 10 This application provides a target ion separation device based on an electrowashed salt configuration, which operates at low current densities (50 A / m³). 2 ) and at high current density (200A / m 2 The concentration of the final target ions obtained by this device is higher than that of traditional electrodialysis, approximately 1 to 2 times higher. Furthermore, compared to traditional electrodialysis, the target ion separation device based on an electrowashing salt configuration in this application reduces the migration rate of retained ions through the selective membrane by 10 to 40% due to the presence of a reservoir. By replenishing the retained ions to the feed chamber through the reservoir, the target ions are actively "pushed" towards the receiving chamber, mitigating the ion competition problem in traditional electrodialysis. This increases the target ion migration rate by 40% to 90%. Combined with the specific permeation function of the selective membrane, only target ions are allowed to pass through, resulting in a final target ion concentration that is 1 to 2 times higher than that of traditional electrodialysis. This device has a wide range of applications, suitable for different target ions such as lithium ions, sodium ions, chloride ions, and nitrate ions. It can be flexibly adapted by changing the selective membrane and the reservoir solution, making it suitable for various scenarios such as brine purification, industrial wastewater recovery, and chemical product refining.

[0091] In summary, the target ion separation device based on the electrowashing salt configuration provided in this application can enhance selective separation through the arrangement of membranes and has strong process flexibility. The configuration parameters can be adjusted according to the impurity composition of different salt solutions to achieve efficient separation and high-concentration collection of target ions, which is suitable for the high-purity salt production needs of multiple industries.

[0092] Example 5: A method for target ion separation based on electrowashed salt configuration

[0093] This application provides a target ion separation method based on an electrowashed salt configuration. This separation method is used in the aforementioned target ion separation device based on an electrowashed salt configuration. The separation method includes:

[0094] Step 1: Introduce sodium sulfate solution or sodium chloride solution into the first and second electrode chambers, introduce a solution corresponding to the ions retained by the selective membrane into the storage chamber, introduce the liquid to be separated into the feed chamber, and introduce the target ion solution into the receiving chamber, while controlling the inlet flow rates of the first electrode chamber, second electrode chamber, storage chamber, feed chamber, and receiving chamber.

[0095] Step 2: Turn on the electrode power supply and apply a constant current to the electrodes of the first and second electrode chambers.

[0096] Step 3: Once the target ions are enriched in the receiving chamber and the target ion concentration is stable, collect the target ion solution.

[0097] In summary, the target ion separation method based on electrowashing salt configuration provided in this application can enhance selective separation through membrane arrangement and has strong process flexibility. The configuration parameters can be adjusted according to the impurity composition of different salt solutions to achieve efficient separation and high-concentration collection of target ions, which is applicable to the high-purity salt production needs of multiple industries.

[0098] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. The term "multiple" refers to two or more unless otherwise expressly defined.

[0099] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only.

[0100] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A target ion separation device based on an electrowashed salt configuration, characterized in that, The device includes: a first electrode chamber, a first standard ion exchange membrane adjacent to the first electrode chamber, and a second electrode chamber; The electrodes in the first and second polarity chambers have opposite polarities; At least one unit membrane stack is provided between the first standard ion exchange membrane and the second electrode chamber; The unit membrane stack includes a storage chamber, a second standard ion exchange membrane, a feed liquid chamber, a selective membrane, a receiving chamber, and a third standard ion exchange membrane arranged sequentially. The first standard ion exchange membrane and the second standard ion exchange membrane are ion exchange membranes with opposite charges. The second standard ion exchange membrane and the selective membrane have the same charge. The first standard ion exchange membrane and the third standard ion exchange membrane have the same charge.

2. The target ion separation device based on an electrowashed salt configuration according to claim 1, characterized in that, The electrode solutions in the first and second electrode chambers are sodium sulfate or sodium chloride solutions with a concentration of 0.3-0.5 mol / L.

3. The target ion separation device based on an electrowashed salt configuration according to claim 2, characterized in that, When the target ion is a cation, the built-in electrode in the first electrode chamber is the anode, and the first standard ion exchange membrane is the anion membrane; When the target ion is an anion, the built-in electrode in the first electrode chamber is the cathode, and the first standard ion exchange membrane is the cation membrane.

4. The target ion separation device based on an electrowashed salt configuration according to claim 1, characterized in that, A solution corresponding to the ions retained by the selective membrane is introduced into the storage chamber, and the concentration of the solution corresponding to the ions retained by the selective membrane is 0.5~3 mol / L.

5. The target ion separation device based on an electrowashed salt configuration according to claim 1, characterized in that, The feed chamber is circulated with the liquid to be separated.

6. The target ion separation device based on an electrowashed salt configuration according to claim 1, characterized in that, The receiving chamber is circulated with a target ion solution, the concentration of which is 0.01~0.1 mol / L.

7. The target ion separation device based on an electrowashed salt configuration according to claim 1, characterized in that, The inlet flow rate of the first electrode chamber, the second electrode chamber, the storage chamber, the feed liquid chamber, and the receiving chamber is 10~35L / h.

8. The target ion separation device based on an electrowashed salt configuration according to claim 1, characterized in that, The constant current applied to the electrodes of the first and second electrode chambers has a current density of 50~200 A / m. 2 .

9. A method for separating target ions based on electrowashed salt configuration, characterized in that, The separation method is used in the target ion separation device based on the electrowashed salt configuration according to any one of claims 1-8, characterized in that the separation method comprises: Step 1: Introduce sodium sulfate solution or sodium chloride solution into the first and second electrode chambers, introduce a solution corresponding to the ions retained by the selective membrane into the storage chamber, introduce the liquid to be separated into the feed chamber, and introduce the target ion solution into the receiving chamber, while controlling the inlet flow rates of the first electrode chamber, second electrode chamber, storage chamber, feed chamber, and receiving chamber. Step 2: Turn on the electrode power supply and apply a constant current to the electrodes of the first and second electrode chambers; Step 3: Once the target ions are enriched in the receiving chamber and the target ion concentration is stable, collect the target ion solution.

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