Testing device and method for testing service life of electrodialysis ion exchange membrane

Abstract

The present invention discloses a testing device and method for testing the service life of an electrodialysis ion exchange membrane, relating to the technical field of ion exchange membrane testing devices. The testing device for testing the service life of an electrodialysis ion exchange membrane comprises: two test chambers, a test membrane, an electric field applying device, a voltage acquisition device, and a control system. Both test chambers are used to contain solutions containing anions and cations, and the two test chambers are connected; the test membrane is an ion exchange membrane; in a test state, the test membrane is arranged on a path connecting the two test chambers and cuts off the connection between the two test chambers; the electric field applying device applies an electric field to the two test chambers and is capable of changing the direction of the electric field; the voltage acquisition device acquires the voltage of the test membrane between the two test chambers; and the control system is in communication with the electric field applying device and the voltage acquisition device and acquires voltage and current values ​​in real time. The present invention can improve the accuracy and reliability of test results.

Description

Technical Field

[0001] The present invention relates to the technical field of ion exchange membrane testing devices, in particular to a testing device and method for testing the service life of an electrodialysis ion exchange membrane. Background Art

[0002] In the field of electrodialysis technology, ion exchange membranes are core components, and their performance is directly related to the efficiency and effectiveness of the electrodialysis process. Ion exchange membranes are primarily used to separate and purify ions in solutions and are widely used in industries such as water treatment, chemicals, pharmaceuticals, and environmental protection. However, the service life of ion exchange membranes varies significantly under different material environments, which is mainly affected by the material composition, concentration, temperature, and the properties of the membrane material itself. Certain extreme materials can adhere to the surface of the ion exchange membrane, causing a significant increase in the membrane's surface resistance, affecting processing capacity and energy consumption. Some organic solvents also have a strong dissolving effect on the membrane, destroying the ion exchange membrane structure and reducing selectivity. Therefore, accurately assessing the service life of ion exchange membranes in specific material environments is of great significance for optimizing the electrodialysis process, reducing operating costs, and improving production efficiency.

[0003] In related technologies, the service life of ion exchange membranes is often tested using static immersion or simple electrodialysis experiments. The data obtained by these methods often fail to accurately reflect the actual service life of the membrane under specific material conditions, which can mislead process optimization and membrane material selection. Furthermore, the lack of real-time monitoring methods makes it impossible to continuously record the dynamic changes in membrane performance over time, making it difficult to identify key points of membrane performance degradation. Furthermore, to maintain stable test conditions, frequent manual adjustments and interventions are required, which not only increases testing costs but also reduces the reliability of test results. Summary of the Invention

[0004] The purpose of the present invention is to provide a testing device and method for testing the service life of an electrodialysis ion exchange membrane, so as to solve the problems existing in the above-mentioned prior art and improve the accuracy and reliability of the test results.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The present invention provides a testing device for testing the service life of an electrodialysis ion exchange membrane, comprising: two test chambers, a test membrane, an electric field applying device, a voltage acquisition device, and a control system. The two test chambers are each used to contain a solution containing anions and cations, and the two test chambers are connected; the test membrane is an ion exchange membrane; in a testing state, the test membrane is disposed on a path connecting the two test chambers and cuts off the connection between the two test chambers; the electric field applying device applies an electric field to the two test chambers, and is capable of changing the direction of the electric field; the voltage acquisition device acquires the voltage of the test membrane between the two test chambers; and the control system is in communication with the electric field applying device and the voltage acquisition device, and acquires voltage and current values ​​in real time.

[0007] Preferably, the voltage acquisition device includes a voltmeter and two Ag-AgCl electrodes; the two Ag-AgCl electrodes are respectively placed in the solutions in the two test cavities; and the voltmeter is connected to the two Ag-AgCl electrodes.

[0008] Preferably, a Luggin capillary is provided outside the two Ag-AgCl electrodes, and the tip of the Luggin capillary is in close contact with the test membrane.

[0009] Preferably, the electric field applying device includes two auxiliary chambers, two platinum electrodes, two auxiliary diaphragms, a DC power supply, and a positive-negative pole reversing device; the two auxiliary chambers are respectively connected to the two test chambers; the two auxiliary diaphragms are respectively arranged on the communication paths between the two auxiliary chambers and the two test chambers and cut off the communication between the auxiliary chambers and the test chambers; the auxiliary diaphragms and the test diaphragms have opposite ion selectivity; the two platinum electrodes are respectively placed in the two auxiliary chambers, and the positive and negative poles of the DC power supply are electrically connected to the two platinum electrodes through the positive-negative pole reversing device; the test chamber contains polar liquid, and when the control system detects that the voltage between the two test chambers is greater than the set threshold, it controls the positive-negative pole reversing device to switch the direction of the electric field.

[0010] Preferably, it comprises two bilateral compartments and two unilateral compartments, and one unilateral compartment, one bilateral compartment, another bilateral compartment and another unilateral compartment are arranged in sequence and connected in sequence; the test cavity is formed in the bilateral compartment, and the auxiliary cavity is formed in the unilateral compartment.

[0011] Preferably, a sealing gasket is provided between the auxiliary diaphragm and the bilateral compartment and the unilateral compartment; and a sealing gasket is provided between the test diaphragm and the bilateral compartment.

[0012] Preferably, the apparatus further comprises a stirrer configured to stir the solutions in the test cavity and the auxiliary cavity.

[0013] Preferably, the stirrer is a magnetic stirrer, which includes a magnetic rotor and a magnetic drive device; the magnetic rotor is arranged at the bottom of the test cavity and the auxiliary cavity, and the magnetic drive device is arranged below the test cavity and the auxiliary cavity.

[0014] The present invention also provides a method for testing the service life of an electrodialysis ion exchange membrane, using the above-mentioned testing device, comprising:

[0015] a. Start the electric field application device and pass a constant current of fixed intensity through the test membrane; the current density is 100A / m 2 ~10000A / m 2 ;Specific values ​​are determined according to test requirements;

[0016] b. The control system collects the voltage collected by the voltage collection device and the current provided by the electric field application device; when the absolute value of the voltage reading is greater than the set value (0.2V~1V, preferably 0.6V), the electric field application device switches the electric field direction;

[0017] c. Repeat step b; the absolute value of the membrane surface resistance is calculated using the voltage and current values;

[0018] The experiment is stopped when the absolute value of the membrane surface resistance exceeds the set lower limit or upper limit;

[0019] The solution in the test chamber uses the material of the actual working condition to be tested.

[0020] Preferably, a curve showing the absolute value of the membrane surface resistance changing with time is plotted according to the period of switching the electric field. As the number of periods of switching the electric field increases, if the curve deviates significantly from the previous one, the membrane life time can be determined and the experiment can be stopped.

[0021] Compared with the prior art, the present invention has achieved the following technical effects:

[0022] The testing device and method provided by the present invention can simulate the actual usage scenarios of ion exchange membranes, thereby improving the accuracy of life prediction; an electric field application device is used to apply an electric field to two test chambers and change the direction of the electric field, thereby enabling continuous testing without human intervention, significantly increasing the test time and test accuracy; by calculating the change in the membrane surface resistance value of the ion exchange membrane over time, the performance degradation of the ion exchange membrane in a specific material environment can be accurately evaluated, thereby predicting its service life in a specific material environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic structural diagram of a testing device for testing the service life of an electrodialysis ion exchange membrane provided in an embodiment of the present invention;

[0025] In the figure: 1-bilateral compartment; 2-unilateral compartment; 3-magnetic rotor; 4-magnetic stirrer; 5-Luggin capillary; 6-Ag-AgCl electrode; 7-voltmeter; 8-DC power supply; 9-positive and negative pole switching device; 10-platinum electrode; 11-control system; 12-sealing gasket; 13-test diaphragm; 14-auxiliary diaphragm. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] The following combination Figure 1 , describing embodiments of the present invention.

[0029] The present invention provides a testing device for testing the service life of an electrodialysis ion exchange membrane, comprising: two test chambers, a test membrane 13, an electric field applying device, a voltage acquisition device, and a control system 11. Both test chambers are used to contain solutions containing anions and cations, the solutions being materials from the actual working conditions to be tested, and the two test chambers are connected; the test membrane 13 is an ion exchange membrane; in a test state, the test membrane 13 is disposed on a path connecting the two test chambers and cuts off the connection between the two test chambers; the electric field applying device applies an electric field to the two test chambers and is capable of changing the direction of the electric field; the voltage acquisition device acquires the voltage of the test membrane between the two test chambers; the control system 11 is communicatively connected to the electric field applying device and the voltage acquisition device and acquires voltage and current values ​​in real time, thereby facilitating the calculation of the membrane surface resistance of the ion exchange membrane. By calculating the change in the membrane surface resistance over time, the performance degradation of the ion exchange membrane in a specific material environment can be accurately assessed, thereby predicting its service life.

[0030] The testing device provided in the embodiment of the present invention can simulate the actual usage scenarios of ion exchange membranes, thereby improving the accuracy of life prediction; an electric field application device is used to apply an electric field to two test chambers and change the direction of the electric field, thereby enabling continuous testing without human intervention, significantly increasing the test time and test accuracy; by calculating the change in the membrane surface resistance value of the ion exchange membrane over time, the performance degradation of the ion exchange membrane in a specific material environment can be accurately evaluated, thereby predicting its service life in a specific material environment.

[0031] In this specification, cutting off the communication between two cavities by an ion exchange membrane means that ions in one cavity must pass through the ion exchange membrane between the two cavities when entering the other cavity.

[0032] In some embodiments, the voltage acquisition device includes a voltmeter 7 and two Ag-AgCl electrodes 6; the two Ag-AgCl electrodes 6 are placed in the solutions in the two test chambers respectively; the voltmeter 7 is connected to the two Ag-AgCl electrodes 6. Luggin capillaries 5 are provided outside the two Ag-AgCl electrodes 6.

[0033] In this embodiment, the voltage value between the solutions in the two test chambers is collected by the voltmeter 7 and transmitted to the control system 11 .

[0034] In some embodiments, the electric field applying device includes two auxiliary chambers, two platinum electrodes 10, two auxiliary diaphragms 14, a DC power supply 8, and a positive-negative pole reversing device 9; the two auxiliary chambers are respectively connected to the two test chambers; the two auxiliary diaphragms 14 are respectively arranged on the communication paths between the two auxiliary chambers and the two test chambers and cut off the communication between the auxiliary chambers and the test chambers; the auxiliary diaphragm 14 and the test diaphragm 13 have opposite ion selectivity; the two platinum electrodes 10 are respectively placed in the two auxiliary chambers, and the positive and negative poles of the DC power supply 8 are electrically connected to the two platinum electrodes 10 through the positive-negative pole reversing device 9; the test chamber contains an electrode liquid, which is one or more of sodium sulfate, sodium chloride, and sodium hydroxide, with a mass fraction of 3% to 5%, preferably 4%. When the control system 11 detects that the voltage between the two test chambers is greater than the set threshold, it controls the positive-negative pole reversing device 9 to switch the direction of the electric field.

[0035] This embodiment eliminates the need for frequent manual intervention, significantly improving test efficiency. Furthermore, the positive-negative polarity reversal device 9 automatically switches the current direction, extending test time and increasing the richness and accuracy of test data. Furthermore, this embodiment ensures a uniform current flow, or electric field, within the test chamber, facilitating uniform ion penetration through the test membrane 13.

[0036] In some embodiments, two bilateral compartments 1 and two unilateral compartments 2 are included, and one unilateral compartment 2, one bilateral compartment 1, another bilateral compartment 1 and another unilateral compartment 2 are arranged in sequence and connected in sequence; the test cavity is formed in the bilateral compartment 1, and the auxiliary cavity is formed in the unilateral compartment 2.

[0037] This embodiment realizes the construction of the test cavity and the auxiliary cavity.

[0038] In some embodiments, a sealing gasket 12 is provided between the auxiliary diaphragm 14 and the bilateral compartment 1 and the unilateral compartment 2 ; and a sealing gasket 12 is provided between the test diaphragm 13 and the bilateral compartment 1 .

[0039] This embodiment avoids leakage of liquid between adjacent cavities, thereby improving the accuracy of the results.

[0040] In some embodiments, the embodiments of the present invention further include an agitator, which is configured to stir the solutions in the test chamber and the auxiliary chamber. Specifically, the agitator is a magnetic agitator 4, which includes a magnetic rotor 3 and a magnetic drive device; the magnetic rotor 3 is arranged at the bottom of the test chamber and the auxiliary chamber, and the magnetic drive device is arranged below the test chamber and the auxiliary chamber. The rotation speed of the magnetic rotor 3 is 100~300r / min, which can increase the diffusion of the solution and reduce the concentration polarization phenomenon. In addition, this embodiment is convenient for simulating actual use conditions. When the agitator is not set in the actual use conditions, the agitator can be turned off.

[0041] In some embodiments, the control system 11 in the present invention has a display interface, which is used to display the parameter information of each component and a curve chart of the detected voltage, current and membrane surface resistance value changing with time, where the horizontal axis is time and the vertical axis is the membrane surface resistance value. This embodiment takes into account the user's operating convenience and adopts a user-friendly interface and simple operation process, so that users can easily get started and quickly complete the test task.

[0042] In some embodiments, the testing device of the present invention can be expanded and customized according to user needs. For example, more sensors and testing modules can be added to test and analyze more performance parameters of the ion exchange membrane.

[0043] The present invention also provides a method for testing the service life of an electrodialysis ion exchange membrane, using the above-mentioned testing device, comprising:

[0044] a. Start the electric field application device and pass a constant current of fixed intensity through the test membrane 13; the current density is 100A / m 2 ~10000A / m 2 ;Specific values ​​are determined according to test requirements;

[0045] b. The control system 11 collects the voltage collected by the voltage collection device and the current provided by the electric field application device; when the absolute value of the voltage reading is greater than the set value, the electric field application device switches the electric field direction;

[0046] c. Repeat step b; the absolute value of the membrane surface resistance is calculated using the voltage and current values;

[0047] The experiment is stopped when the absolute value of the membrane surface resistance exceeds the set lower limit or upper limit;

[0048] The solution in the test chamber uses the material of the actual working condition to be tested.

[0049] The testing method provided in the embodiment of the present invention can simulate the actual usage scenarios of ion exchange membranes, thereby improving the accuracy of life prediction; an electric field application device is used to apply an electric field to two test chambers and change the direction of the electric field, thereby enabling continuous testing without human intervention, significantly increasing the test time and test accuracy; by calculating the change in the membrane surface resistance value of the ion exchange membrane over time, the performance degradation of the ion exchange membrane in a specific material environment can be accurately evaluated, thereby predicting its service life in a specific material environment.

[0050] In some embodiments, a curve is plotted showing the absolute value of the membrane surface resistance versus time, based on the switching cycle of the electric field. As the number of switching cycles increases, if the curve deviates significantly from the previous value, the membrane lifespan can be determined and the experiment terminated. (Deviations can be positive or negative, both of which are considered abnormal. A significant increase in membrane surface resistance may indicate membrane blockage or shedding of membrane functional groups; a significant decrease in membrane surface resistance may indicate structural dissolution of the membrane, leading to material leakage.)

[0051] The principle behind the device and method provided by this invention is that determining the service life of an ion exchange membrane in a specific material has long been a pressing challenge in the field of electrodialysis. This device can individually measure changes in the membrane resistance and processing capacity of a cation or anion exchange membrane in a specific material, thereby indirectly demonstrating the membrane's stability and service life.

[0052] Specifically, under the influence of an electric field, ions in the material penetrate the test membrane 13, generating a transmembrane potential on both sides of the membrane. Dividing the transmembrane potential (i.e., voltage) by the current yields the membrane surface resistance that changes over time. This value can better reflect the contamination and dissolution status of the membrane.

[0053] As the electrodialysis process continues, salt from one bilateral compartment (1) continuously migrates to the other, reducing the salt content and increasing the resistance. To maintain a constant current intensity, the voltage difference across the membrane continuously increases. When the voltage exceeds a certain value, the salt content in the desalination compartment is too low to support long-term continuous testing.

[0054] At this point, the positive-negative polarity reversal device 9 switches the current direction, causing the salt to migrate in the opposite direction. This allows for continuous testing without human intervention, significantly increasing test time and accuracy.

[0055] The test parameters (such as current intensity, stirring speed, etc.) in the present invention can be flexibly adjusted according to actual needs to meet the requirements of different test scenarios.

[0056] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A testing device for testing the service life of an electrodialysis ion exchange membrane, characterized in that: include: Two test chambers, both for containing solutions containing anions and cations, the two test chambers being in communication; The test membrane is an ion exchange membrane; In the test state, the test diaphragm is arranged on the path connecting the two test cavities and cuts off the communication between the two test cavities; an electric field applying device for applying an electric field to the two test cavities; and can change the direction of the electric field; Voltage acquisition device; Collect the voltage of the test diaphragm between the two test cavities; A control system is communicated with the electric field applying device and the voltage collecting device and collects voltage and current values ​​in real time; the electric field applying device includes two auxiliary chambers, two platinum electrodes, two auxiliary diaphragms, a DC power supply, and a positive-negative pole switching device; the two auxiliary chambers are respectively connected to the two test chambers; the two auxiliary diaphragms are respectively arranged on the communication paths between the two auxiliary chambers and the two test chambers and cut off the communication between the auxiliary chambers and the test chambers; the auxiliary diaphragms and the test diaphragms have opposite ion selectivity; the two platinum electrodes are respectively placed in the two auxiliary chambers, and the positive and negative poles of the DC power supply are electrically connected to the two platinum electrodes through the positive-negative pole switching device; the test chamber contains polar liquid, and when the control system detects that the voltage between the two test chambers is greater than a set threshold, it controls the positive-negative pole switching device to switch the direction of the electric field.

2. The testing device for testing the service life of an electrodialysis ion exchange membrane according to claim 1, characterized in that: The voltage acquisition device includes a voltmeter and two Ag-AgCl electrodes; the two Ag-AgCl electrodes are respectively placed in the solutions in the two test cavities; and the voltmeter is connected to the two Ag-AgCl electrodes.

3. The testing device for testing the service life of an electrodialysis ion exchange membrane according to claim 2, characterized in that: Luggin capillaries are provided outside the two Ag-AgCl electrodes, and the tips of the Luggin capillaries are in close contact with the test diaphragm.

4. The testing device for testing the service life of an electrodialysis ion exchange membrane according to claim 1, characterized in that: It comprises two bilateral compartments and two unilateral compartments, wherein one unilateral compartment, one bilateral compartment, another bilateral compartment and another unilateral compartment are arranged in sequence and connected in sequence; the test cavity is formed in the bilateral compartments, and the auxiliary cavity is formed in the unilateral compartment.

5. The testing device for testing the service life of an electrodialysis ion exchange membrane according to claim 4, characterized in that: Sealing gaskets are provided between the auxiliary diaphragm and the bilateral compartments and the unilateral compartment; and sealing gaskets are provided between the test diaphragm and the bilateral compartments.

6. The testing device for testing the service life of an electrodialysis ion exchange membrane according to claim 1, characterized in that: Also included is a stirrer configured to stir the solutions in the test cavity and the auxiliary cavity.

7. The testing device for testing the service life of an electrodialysis ion exchange membrane according to claim 6, characterized in that: The stirrer is a magnetic stirrer, which includes a magnetic rotor and a magnetic drive device; the magnetic rotor is arranged at the bottom of the test cavity and the auxiliary cavity, and the magnetic drive device is arranged below the test cavity and the auxiliary cavity.

8. A method for testing the service life of an electrodialysis ion exchange membrane, characterized in that: The testing device according to any one of claims 1 to 7, comprising: a. Start the electric field application device and pass a constant current of fixed intensity through the test membrane; the current density is 100A / m 2 ~10000A / m 2 ;Specific values ​​are determined according to test requirements; b. The control system collects the voltage collected by the voltage collection device and the current provided by the electric field application device; when the absolute value of the voltage reading is greater than the set value, the electric field application device switches the electric field direction; c. Repeat step b; the absolute value of the membrane surface resistance is calculated using the voltage and current values; The experiment is stopped when the absolute value of the membrane surface resistance exceeds the set lower limit or upper limit; The solution in the test chamber uses the material of the actual working condition to be tested.

9. The method for testing the service life of an electrodialysis ion exchange membrane according to claim 8, wherein: According to the cycle of switching electric field, a curve of the absolute value of membrane surface resistance changing with time is drawn; as the number of cycles of switching electric field increases, when the curve deviates significantly from the previous one, the life span of the membrane can be determined and the experiment can be stopped.

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