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

Abstract

The invention discloses a testing device and method for testing the service life of an electrodialysis ion exchange membrane, and relates to the technical field of ion exchange membrane testing devices.The testing device for testing the service life of the electrodialysis ion exchange membrane comprises two testing cavities, a testing membrane, an electric field applying device, a voltage collecting device and a control system. The two test cavities are both used for accommodating a solution containing anions and cations, and the two test cavities are communicated with each other; the test membrane is an ion exchange membrane; in a test state, the test diaphragm is arranged on a path for communicating the two test cavities and cuts off the communication between the two test cavities; the electric field applying device applies an electric field to the two test cavities; the electric field direction can be changed; the voltage acquisition device acquires the voltage of the test diaphragm between the two test cavities; the control system is in communication connection with the electric field applying device and the voltage acquisition device and acquires voltage and current values in real time. According to the invention, the accuracy and reliability of test results can be improved.

Description

Technical Field

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

[0002] In the field of electrodialysis technology, as a core component, the performance of ion exchange membranes is directly related to the efficiency and effect of the electrodialysis process. Ion exchange membranes are mainly used for separating and purifying ions in solutions and are widely applied in multiple industries such as water treatment, chemical engineering, medicine, and environmental protection. However, the service lives of ion exchange membranes vary significantly under different material environments, which are mainly affected by material composition, concentration, temperature, and the properties of the membrane material itself. Some extreme materials will adhere to the surface of the ion membrane, causing a significant increase in membrane surface resistance, affecting the treatment capacity and energy consumption. There are also some organic solvents that have a strong dissolving and damaging effect on the membrane, resulting in the destruction of the ion membrane structure and a decrease in selectivity. Therefore, accurately evaluating the service life of ion exchange membranes under 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 testing of ion exchange membranes mostly adopts static immersion or simple electrodialysis experimental methods. The data obtained by the above methods often cannot accurately reflect the true service life of the membrane under specific material environments, misleading the process optimization and membrane material selection. In addition, there is a lack of real-time monitoring means, unable to continuously record the dynamic changes of membrane performance over time, and it is difficult to capture the key nodes of membrane performance decline. Moreover, in order to maintain the stability of the test conditions, frequent manual adjustment and intervention are required, which not only increases the test cost but also reduces the reliability of the 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 electrodialysis ion exchange membranes to solve the problems existing in the above-mentioned prior art and improve the accuracy and reliability of test results.

[0005] To achieve the above purpose, the present invention provides the following solutions: The present invention provides a test 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 collecting device, and a control system. Both of the two test chambers are used for accommodating a solution containing cations and anions, and the two test chambers are communicated with each other; the test membrane is an ion exchange membrane; in a test state, the test membrane is arranged on the path where the two test chambers are communicated and cuts off the communication between the two test chambers; the electric field applying device applies an electric field to the two test chambers and can change the direction of the electric field; the voltage collecting device collects the voltage of the test membrane between the two test chambers; the control system is communicatively connected with the electric field applying device and the voltage collecting device and collects voltage and current values in real time.

[0006] Preferably, the voltage collecting device comprises a voltmeter and two Ag-AgCl electrodes; the two Ag-AgCl electrodes are respectively placed in the solutions in the two test chambers; the voltmeter is connected with the two Ag-AgCl electrodes.

[0007] Preferably, Luggin capillaries are arranged outside both of the two Ag-AgCl electrodes, and the tips of the Luggin capillaries are closely attached to the test membrane.

[0008] Preferably, the electric field applying device comprises two auxiliary chambers, two platinum electrodes, two auxiliary membranes, a DC power supply, and a positive and negative pole reversing device; the two auxiliary chambers are respectively communicated with the two test chambers; the two auxiliary membranes 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 membranes and the test membrane have opposite ion selectivities; 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 with the two platinum electrodes through the positive and negative pole reversing device; an electrode solution is accommodated in the test chamber, and when the control system collects that the voltage between the two test chambers is greater than a set threshold value, the positive and negative pole reversing device is controlled to switch the direction of the electric field.

[0009] Preferably, it comprises two bilateral compartments and two unilateral compartments, and one unilateral compartment, one bilateral compartment, the other bilateral compartment, and the other unilateral compartment are arranged in sequence and communicated in sequence; the test chamber is formed in the bilateral compartment, and the auxiliary chamber is formed in the unilateral compartment.

[0010] Preferably, sealing gaskets are arranged between the auxiliary membrane and the bilateral compartment and the unilateral compartment; sealing gaskets are arranged between the test membrane and the bilateral compartment.

[0011] Preferably, it further comprises a stirrer, and the stirrer is configured to stir the solutions in the test chamber and the auxiliary chamber.

[0012] Preferably, the stirrer is a magnetic stirrer, which includes a magnetic rotor and a magnetic drive device; the magnetic rotor is arranged at the bottoms of the test chamber and the auxiliary chamber, and the magnetic drive device is arranged below the test chamber and the auxiliary chamber.

[0013] The present invention also provides a test method for testing the service life of an electrodialysis ion exchange membrane. Using the test device as described above, it includes: a. Start the electric field application device to enable the test membrane to pass through a constant current with a fixed intensity; the current density is 100 A / m 2 ~10000 A / m 2 ; the specific value is determined according to the 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 (0.2 V~1 V, preferably 0.6 V), the electric field application device switches the direction of the electric field; c. Repeat b; the absolute value of the membrane surface resistance value is calculated through the voltage value and the current value; Stop the experiment until the absolute value of the membrane surface resistance value exceeds the set lower limit or upper limit; The solution in the test chamber is the material under the actual working conditions to be measured.

[0014] Preferably, according to the cycle of switching the electric field, draw a curve of the absolute value of the membrane surface resistance value changing with time. As the number of cycles of switching the electric field increases, after the curve deviates significantly from the previous one, the life time of the membrane can be determined and the experiment can be stopped.

[0015] The present invention has achieved the following technical effects compared with the prior art: The test device and method provided by the present invention can simulate the actual use scenario of the ion exchange membrane, thereby improving the accuracy of predicting the service life; using the electric field application device to apply an electric field to the two test chambers and change the direction of the electric field, so that continuous testing without manual intervention can be carried out, significantly increasing the testing time and testing accuracy; by calculating the change of the membrane surface resistance value of the ion exchange membrane with time, the performance degradation of the ion exchange membrane in a specific material environment can be accurately evaluated, so as to predict its service life in a specific material environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0017] Figure 1Schematic structural diagram of a test device for testing the service life of an electrodialysis ion exchange membrane provided by an embodiment of the present invention; 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 inversion device; 10 - platinum electrode; 11 - control system; 12 - sealing gasket; 13 - test membrane; 14 - auxiliary membrane. Detailed implementation manners

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0020] Next, in conjunction with Figure 1 , embodiments of the present invention will be described.

[0021] The present invention provides a test device for testing the service life of an electrodialysis ion exchange membrane, including: two test chambers, a test membrane 13, an electric field application device, a voltage acquisition device, and a control system 11. Both test chambers are used to accommodate a solution containing cations and anions, and the solution uses the material under the actual working conditions to be measured. The two test chambers are connected; the test membrane 13 is an ion exchange membrane; in the test state, the test membrane 13 is arranged on the path where the two test chambers are connected and cuts off the connection between the two test chambers; the electric field application device applies an electric field to the two test chambers and can change 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 application device and the voltage acquisition device and real - time acquires voltage and current values, thereby facilitating the calculation of the membrane surface resistance value of the ion exchange membrane. By calculating the change of the membrane surface resistance value over time, the performance degradation of the ion exchange membrane in a specific material environment can be accurately evaluated, so as to predict its service life.

[0022] The test device provided by the embodiment of the present invention can simulate the actual use scenario of the ion exchange membrane, thereby improving the accuracy of predicting the service life; an electric field application device is used to apply an electric field to two test chambers and change the direction of the electric field, so that continuous testing without manual intervention can be carried out, significantly increasing the testing time and testing accuracy; by calculating the change of 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, so as to predict its service life in a specific material environment.

[0023] In the specification, the connection between the two cavities is cut off by the ion exchange membrane, which means that when ions in one cavity enter another cavity, they must pass through the ion exchange membrane between the two.

[0024] In some embodiments, the voltage acquisition device includes a voltmeter 7 and two Ag-AgCl electrodes 6; the two Ag-AgCl electrodes 6 are respectively placed in the solutions in the two test chambers; the voltmeter 7 is connected to the two Ag-AgCl electrodes 6. Luggin capillaries 5 are arranged outside both of the two Ag-AgCl electrodes 6.

[0025] In this embodiment, the voltmeter 7 is used to collect the voltage value between the solutions in the two test chambers and transmit it to the control system 11.

[0026] In some embodiments, the electric field application device includes two auxiliary chambers, two platinum electrodes 10, two auxiliary diaphragms 14, a DC power supply 8, and a positive and negative pole inversion device 9; the two auxiliary chambers are respectively communicated with 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 diaphragms 14 and the test diaphragm 13 have opposite ion selectivities; 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 and negative pole inversion device 9; the test chamber contains an electrode solution, and the electrode solution 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 collects that the voltage between the two test chambers is greater than the set threshold, the positive and negative pole inversion device 9 is controlled to switch the direction of the electric field.

[0027] This embodiment does not require frequent manual intervention, significantly improving the testing efficiency. At the same time, the automatic switching of the current direction is realized through the positive and negative pole inversion device 9, extending the testing time and increasing the richness and accuracy of the test data. In addition, this embodiment makes the current or the electric field in the test chamber uniform, which is beneficial to the uniform permeation of ions through the test diaphragm 13.

[0028] In some embodiments, there are two bilateral compartments 1 and two unilateral compartments 2. One unilateral compartment 2, one bilateral compartment 1, another bilateral compartment 1, and another unilateral compartment 2 are arranged in sequence and communicate with each other in sequence. A test chamber is formed within the bilateral compartment 1, and an auxiliary chamber is formed within the unilateral compartment 2.

[0029] This embodiment realizes the construction of the test chamber and the auxiliary chamber.

[0030] In some embodiments, sealing gaskets 12 are provided between the auxiliary diaphragm 14 and both the bilateral compartment 1 and the unilateral compartment 2; sealing gaskets 12 are provided between the test diaphragm 13 and the bilateral compartment 1.

[0031] This embodiment avoids the mutual leakage of liquids between adjacent cavities and improves the accuracy of the results.

[0032] In some embodiments, the embodiment of the present invention further includes a stirrer, and the stirrer is configured to stir the solutions in the test chamber and the auxiliary chamber. Specifically, the stirrer is a magnetic stirrer 4, and the magnetic stirrer 4 includes a magnetic rotor 3 and a magnetic driving device; the magnetic rotor 3 is arranged at the bottom of the test chamber and the auxiliary chamber, and the magnetic driving device is arranged below the test chamber and the auxiliary chamber. The rotational speed of the magnetic rotor 3 is 100 - 300 r / min, which can increase the diffusion of the solution and reduce the phenomenon of concentration polarization. In addition, this embodiment facilitates simulating the actual use conditions. When there is no stirrer in the actual use conditions, the stirrer can be turned off.

[0033] In some embodiments, the control system 11 in the present invention has a display interface, and the display interface is used to display the parameter information of each component and the curve graphs of the detected voltage, current, and membrane surface resistance value changing with time, where the abscissa is time and the ordinate is the membrane surface resistance value. This embodiment takes into account the convenience of user operation, adopts a user-friendly interface and a simple operation process, enabling the user to easily get started and quickly complete the test task.

[0034] In some embodiments, the test device in the present invention can be functionally expanded and customized according to the user's needs. For example, more sensors and test modules can be added to realize the testing and analysis of more performance parameters of the ion exchange membrane.

[0035] The present invention also provides a test method for testing the service life of an electrodialysis ion exchange membrane, using the test device as described above, including: a. Start the electric field applying device to make the test diaphragm 13 pass through a constant current of a fixed intensity; the current density is 100 A / m 2 ~10000 A / m 2 ; the specific value is determined according to the test requirements; 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 direction of the electric field; c. Repeat step b; the absolute value of the membrane surface resistance value is calculated from the voltage value and the current value; Stop the experiment until the absolute value of the membrane surface resistance value exceeds the set lower limit or upper limit; The solution in the test chamber is the material under the actual working conditions to be measured.

[0036] The test method provided by the embodiments of the present invention can simulate the actual use scenario of the ion exchange membrane, thereby improving the accuracy of predicting the service life; an electric field application device is used to apply an electric field to two test chambers and change the direction of the electric field, so that continuous testing without manual intervention can be carried out, significantly increasing the test time and test accuracy; by calculating the change of 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.

[0037] In some embodiments, according to the cycle of switching the electric field, a curve of the absolute value of the membrane surface resistance value changing with time is plotted. As the number of cycles of switching the electric field increases, after the curve deviates significantly from the previous one, the membrane sheet life time can be determined and the experiment is stopped. (The deviation may be positive or negative, both of which are abnormal. A significant increase in the membrane surface resistance may be due to membrane blockage or membrane functional group shedding; a significant decrease in the membrane surface resistance may be due to structural dissolution of the membrane, resulting in material leakage).

[0038] The principle of the device method provided by the present invention: How to determine the service life of an ion exchange membrane in a certain material has always been an urgent problem to be solved in the field of electrodialysis. This device can separately test the membrane resistance and the change of the treatment capacity performance of a certain cation exchange membrane or anion exchange membrane in a specific material, thereby indirectly showing the stability and service life of the membrane.

[0039] Specifically: Under the action of an electric field, ions in the material penetrate the test membrane sheet 13, generating a transmembrane potential on both sides of the membrane sheet. According to the transmembrane potential (i.e., voltage) divided by the current, the membrane surface resistance value changing with time can be obtained, and the change of this value can better reflect the pollution condition and dissolution condition of the membrane.

[0040] Due to the continuation of the electrodialysis process, the salt in a certain bilateral compartment 1 continuously migrates to another bilateral compartment 1, the salt content decreases, and the resistance increases. In order to maintain the constant current intensity, the voltage difference on both sides of the membrane sheet continuously increases. After the voltage is higher than a certain value, it means that the salt content in the desalination compartment is too low to support long-term continuous testing.

[0041] At this time, the current direction is switched by the positive and negative pole inversion device 9, and the salt begins to migrate in the reverse direction accordingly. Thus, continuous testing without manual intervention can be carried out, significantly increasing the testing time and testing accuracy.

[0042] In the present invention, the test parameters (such as current intensity, stirring speed, etc.) can be flexibly adjusted according to actual needs to meet the requirements of different test scenarios.

[0043] In the present invention, specific examples are used to illustrate the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A test device for testing the service life of an electrodialysis ion exchange membrane, characterized in that: Comprising: Two test chambers, both for accommodating solutions containing cations and anions, and the two test chambers are in communication; A test diaphragm, which is an ion exchange membrane; In the test state, the test diaphragm is arranged on the path where the two test chambers communicate and cuts off the communication between the two test chambers; An electric field applying device for applying an electric field to the two test chambers; And capable of changing the direction of the electric field; A voltage acquisition device; To acquire the voltage of the test diaphragm between the two test chambers; A control system, which is communicatively connected to the electric field applying device and the voltage acquisition device and acquires 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 inversion device; the two auxiliary chambers are respectively in communication with 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 diaphragm have opposite ion selectivities; 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 inversion device; the test chamber contains an electrode solution, and when the control system acquires that the voltage between the two test chambers is greater than the set threshold, the positive-negative inversion device is controlled to switch the direction of the electric field.

2. The test device for testing the service life of an electrodialysis ion exchange membrane according to claim 1, wherein: 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 chambers; the voltmeter is connected to the two Ag-AgCl electrodes.

3. The test device for testing the service life of an electrodialysis ion exchange membrane according to claim 2, wherein: Luggin capillaries are arranged outside both of the two Ag-AgCl electrodes, and the tips of the Luggin capillaries are closely attached to the test diaphragm.

4. The test device for testing the service life of an electrodialysis ion exchange membrane according to claim 1, characterized in that: Comprising two bilateral compartments and two unilateral compartments, one of the unilateral compartments, one of the bilateral compartments, the other bilateral compartment, and the other unilateral compartment are arranged in sequence and communicate in sequence; the test chamber is formed in the bilateral compartment, and the auxiliary chamber is formed in the unilateral compartment.

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

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

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, and the magnetic stirrer includes a magnetic rotor and a magnetic driving device; the magnetic rotor is arranged at the bottoms of the test chamber and the auxiliary chamber, and the magnetic driving device is arranged below the test chamber and the auxiliary chamber.

8. A test method for testing the service life of an electrodialysis ion exchange membrane, characterized in that: Using the test device according to any one of claims 1 to 7, comprising: a. Start the electric field application device so that a constant current of a fixed intensity passes through the test diaphragm; the current density is 100 A / m 2 ~10000 A / m 2 ; the specific value is determined according to the test requirements; b. The control system acquires the voltage acquired by the voltage acquisition device and the current provided by the electric field applying device; when the absolute value of the voltage reading is greater than the set value, the electric field applying device switches the direction of the electric field; c. Repeat b; the absolute value of the membrane surface resistance value is calculated by the voltage value and the current value; Stop the experiment until the absolute value of the membrane surface resistance value exceeds the set lower limit or upper limit; Wherein, the solution in the test chamber uses the material under the actual working conditions to be measured.

9. The test method for testing the service life of an electrodialysis ion exchange membrane according to claim 8, characterized in that: A curve of the absolute value of the membrane surface resistance changing with time is plotted according to the period of switching the electric field; after the curve deviates significantly from the previous one as the number of periods of switching the electric field increases, the service life time of the membrane sheet can be determined and the experiment is stopped.

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