A method of cleaning a lead dioxide electrode

Abstract

The application provides a cleaning method of a lead dioxide electrode, which comprises the following steps: firstly, constructing an electrochemical three-electrode system by taking the lead dioxide electrode as a working electrode, an Ag-AgCl electrode as a reference electrode and a platinum wire as a counter electrode, taking sodium sulfate as a supporting electrolyte, and performing an electrochemical reduction reaction in a sodium sulfate solution to reduce lead dioxide on the surface of the lead dioxide electrode into lead sulfate, so that the adsorption of organic matters on the electrode surface is reduced, pollutants are naturally dropped, and the purpose of cleaning the electrode surface is achieved; and then, constructing an electrochemical three-electrode system by taking the lead dioxide electrode obtained in the first step as a working electrode, an Ag-AgCl electrode as a reference electrode and a platinum wire as a counter electrode, taking sodium sulfate as a supporting electrolyte, and performing an electrochemical oxidation reaction in a sodium sulfate solution to oxidize the lead sulfate on the surface of the lead dioxide electrode into lead dioxide, so that the catalytic oxidation activity of the electrode is recovered. The cleaning method can effectively clean the organic matters on the surface of the lead dioxide electrode and improve the test sensitivity of the lead dioxide electrode.

Description

Technical Field

[0001] This invention relates to the field of water detection, and in particular to a method for cleaning a lead dioxide electrode. Background Technology

[0002] Electrochemical sensor technology for detecting organic matter content in water is a green and inexpensive method with broad market prospects. Existing technologies use lead dioxide electrodes as the working electrode in electrochemical sensors for detecting organic matter content in water and for early warning of organic pollution. However, the adsorption of organic matter on the surface of the lead dioxide electrode leads to electrode contamination, which in turn reduces the sensor's sensitivity to organic matter. Therefore, the problem of lead dioxide electrode contamination caused by organic matter adsorption must be solved.

[0003] Anodizing is a commonly used technique in the literature to address organic contamination of lead dioxide electrodes (e.g., Electrochimica Acta 176 (2015) 1100–1107). It cleans the electrode surface by increasing the working potential of the lead dioxide electrode, thereby oxidizing the organic matter adsorbed on the electrode surface. However, due to the excessively high applied potential, water on the electrode surface undergoes electrochemical oxidation and decomposition, generating numerous bubbles. These bubbles damage the microstructure of the lead dioxide electrode, shortening its lifespan. In addition, mechanical polishing, ultrasonic cleaning, and chemical cleaning are also commonly used techniques to address organic adsorption on the electrode surface; however, these techniques require additional mechanical structures or cleaning solutions, increasing the manufacturing and operating costs of water-based organic matter electrochemical sensors. Summary of the Invention

[0004] In view of this, the present invention provides a method for cleaning lead dioxide electrodes. This cleaning method not only effectively cleans organic matter from the surface of the lead dioxide electrode and restores the sensor's sensitivity, but also eliminates the need for additional mechanical structures or cleaning solutions, enabling online cleaning and reducing costs.

[0005] This invention provides a method for cleaning a lead dioxide electrode, comprising the following steps:

[0006] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0007] An electrochemical three-electrode system was constructed using a lead dioxide electrode as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical reduction reaction was carried out in a sodium sulfate solution to reduce the lead dioxide on the surface of the lead dioxide electrode to lead sulfate, thus obtaining an electrochemically reduced lead dioxide electrode.

[0008] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0009] An electrochemical three-electrode system was constructed using the electrochemically reduced lead dioxide electrode as the working electrode, the Ag-AgCl electrode as the reference electrode, and the platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical oxidation reaction was carried out in the sodium sulfate solution to oxidize the lead sulfate on the surface of the lead dioxide electrode to lead dioxide.

[0010] Preferably, in step A), the conditions for the electrochemical reduction reaction are: the potential of the working electrode is -1.0 to -0.4V, and the reduction time is 10 to 400s.

[0011] Preferably, in step A), the concentration of the sodium sulfate solution is 2.8~8.0 g / L.

[0012] Preferably, in step B), the conditions for the electrochemical oxidation reaction are: constant potential of 1.4V and oxidation time of 10~60s.

[0013] Preferably, in step B), the concentration of the sodium sulfate solution is 2.8~8.0 g / L.

[0014] Preferably, in step A), the filling solution in the reference electrode chamber of the Ag-AgCl electrode is a 3M KCl solution.

[0015] Preferably, in step B), the filling solution in the reference electrode chamber of the Ag-AgCl electrode is a 3M KCl solution.

[0016] This invention provides a method for cleaning a lead dioxide electrode. First, an electrochemical three-electrode system is constructed using a lead dioxide electrode as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate is used as the supporting electrolyte, and an electrochemical reduction reaction is carried out in a sodium sulfate solution to reduce the lead dioxide on the lead dioxide electrode surface to lead sulfate, reducing the adsorption of organic matter on the electrode surface and allowing adsorbed contaminants to detach naturally, thus cleaning the electrode surface. Then, the electrochemical three-electrode system is reconstructed using the lead dioxide electrode obtained in the previous step as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate is used as the supporting electrolyte, and an electrochemical oxidation reaction is carried out in a sodium sulfate solution to oxidize the lead sulfate on the lead dioxide electrode surface back to lead dioxide, restoring the electrode's catalytic oxidation activity. This cleaning method not only effectively cleans organic matter from the lead dioxide electrode surface and restores sensor sensitivity, but also eliminates the need for additional mechanical structures or cleaning solutions, enabling online cleaning.

[0017] Experimental results show that, compared with the lead dioxide electrode before cleaning, cleaning the lead dioxide electrode using the cleaning method of the present invention can increase the test sensitivity by more than 6 times. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a test result diagram of the product test in Example 1; wherein, Figure 1 Figure A shows the response signal test diagram of the lead dioxide electrode to be cleaned after initial organic contamination to Nanhu Lake water and coating wastewater. Figure 1 Figure B shows the response signal test diagram of the lead dioxide electrode after cleaning in Example 1 to Nanhu water and coating wastewater. Detailed Implementation

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0021] In this article, the technical features described in an open-ended manner include both closed technical solutions composed of the listed features and open technical solutions that include the listed features.

[0022] As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items.

[0023] In this document, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when a range refers to an integer, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0024] In this article, when referring to units for data ranges, if the unit is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 2.8~8.0 g / L means that the units for the left endpoint "2.8" and the right endpoint "8.0" are both g / L.

[0025] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0026] This invention provides a method for cleaning a lead dioxide electrode, characterized by comprising the following steps:

[0027] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0028] An electrochemical three-electrode system was constructed using a lead dioxide electrode as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical reduction reaction was carried out in a sodium sulfate solution to reduce the lead dioxide on the surface of the lead dioxide electrode to lead sulfate, thus obtaining an electrochemically reduced lead dioxide electrode.

[0029] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0030] An electrochemical three-electrode system was constructed using the electrochemically reduced lead dioxide electrode as the working electrode, the Ag-AgCl electrode as the reference electrode, and the platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical oxidation reaction was carried out in the sodium sulfate solution to oxidize the lead sulfate on the surface of the lead dioxide electrode to lead dioxide.

[0031] Regarding step A) :

[0032] This invention first constructs an electrochemical three-electrode system to carry out an electrochemical reduction reaction. Specifically, the electrochemical three-electrode system is constructed using a lead dioxide electrode as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode.

[0033] In this invention, the lead dioxide electrode is a lead dioxide electrode to be cleaned, that is, an electrode in which contaminants have been adsorbed on the surface of the lead dioxide electrode after a period of use in the electrochemical sensor, and therefore needs to be cleaned. This invention uses the aforementioned electrode as the working electrode.

[0034] In this invention, the Ag-AgCl electrode (i.e., the Ag / AgCl electrode, silver-silver chloride electrode) is a conventional Ag-AgCl electrode, mainly composed of a silver wire plated with silver chloride (with a white polytetrafluoroethylene cap), a glass tube (i.e., the reference electrode chamber), and a "microporous ceramic head" sealed in the glass tube; wherein, the reference electrode chamber is filled with a solution. In this invention, the filling solution in the reference electrode chamber of the Ag-AgCl electrode is preferably a 3M KCl solution, that is, the Ag-AgCl electrode is an Ag-AgCl electrode (3M KCl). This invention uses the above electrode as the reference electrode.

[0035] In this invention, a platinum wire is used as the counter electrode.

[0036] This invention assembles the aforementioned working electrode, reference electrode, and counter electrode into an electrochemical three-electrode system. Simultaneously, sodium sulfate is used as the supporting electrolyte, and an electrochemical reduction reaction is carried out in a sodium sulfate solution (i.e., the supporting electrolyte solution). Preferably, the sodium sulfate solution is an aqueous solution. The concentration of the sodium sulfate solution is preferably 2.8~8.0 g / L, specifically 2.8 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, 6.5 g / L, 7.0 g / L, 7.5 g / L, or 8.0 g / L.

[0037] In this invention, the electrochemical reduction reaction is carried out in the above-mentioned electrochemical three-electrode system. The potential of the working electrode is controlled to be -1.0 to -0.4V, specifically -0.4V, -0.5V, 0.6V, -0.7V, -0.8V, -0.9V, or -1.0V. The preferred time for the electrochemical reduction reaction is 10 to 400 s, specifically 10 s, 50 s, 100 s, 150 s, 200 s, 250 s, 300 s, 350 s, or 400 s.

[0038] Through the above electrochemical reduction reaction, the lead dioxide on the surface of the lead dioxide electrode is reduced to lead sulfate, which reduces the adsorption of organic matter on the electrode surface and allows the adsorbed pollutants to fall off naturally, thus achieving the purpose of cleaning the electrode surface.

[0039] Regarding step B) :

[0040] Following the electrochemical reduction reaction in step A), this invention reconstructs an electrochemical three-electrode system to perform an electrochemical oxidation reaction. Specifically, the electrochemically reduced lead dioxide electrode obtained in step A) is used as the working electrode, the Ag-AgCl electrode as the reference electrode, and the platinum wire as the counter electrode to construct the electrochemical three-electrode system.

[0041] In this invention, the filling solution in the reference electrode chamber of the Ag-AgCl electrode is preferably a 3M KCl solution, i.e., the Ag-AgCl electrode is an Ag-AgCl electrode (3M KCl). This invention uses the above electrode as the reference electrode.

[0042] In this invention, a platinum wire is used as the counter electrode.

[0043] This invention assembles the aforementioned working electrode, reference electrode, and counter electrode into an electrochemical three-electrode system. Simultaneously, sodium sulfate is used as the supporting electrolyte, and the electrochemical oxidation reaction is carried out in a sodium sulfate solution (i.e., the supporting electrolyte solution). Preferably, the sodium sulfate solution is an aqueous solution. The concentration of the sodium sulfate solution is preferably 2.8~8.0 g / L, specifically 2.8 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5.0 g / L, 5.5 g / L, 6.0 g / L, 6.5 g / L, 7.0 g / L, 7.5 g / L, and 8.0 g / L.

[0044] In this invention, the electrochemical oxidation reaction is carried out under the above-mentioned electrochemical three-electrode system. The constant potential is controlled at 1.4V. The preferred time for the electrochemical oxidation reaction is 10~60s, specifically 10s, 20s, 30s, 40s, 50s, or 60s.

[0045] Through the above electrochemical oxidation reaction, the lead sulfate on the surface of the lead dioxide electrode is oxidized to lead dioxide, restoring the catalytic oxidation activity of the electrode.

[0046] In this invention, the supporting electrolyte (sodium sulfate) used in steps A) and B) above is the supporting electrolyte used in online detection of organic matter content in water. No additional reagent tank is required, and online cleaning of lead dioxide electrodes can be achieved.

[0047] This invention provides a method for cleaning a lead dioxide electrode. First, an electrochemical three-electrode system is constructed using a lead dioxide electrode as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate is used as the supporting electrolyte, and an electrochemical reduction reaction is carried out in a sodium sulfate solution to reduce the lead dioxide on the lead dioxide electrode surface to lead sulfate, reducing the adsorption of organic matter on the electrode surface and allowing adsorbed contaminants to detach naturally, thus cleaning the electrode surface. Then, the electrochemical three-electrode system is reconstructed using the lead dioxide electrode obtained in the previous step as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate is used as the supporting electrolyte, and an electrochemical oxidation reaction is carried out in a sodium sulfate solution to oxidize the lead sulfate on the lead dioxide electrode surface back to lead dioxide, restoring the electrode's catalytic oxidation activity. This cleaning method not only effectively cleans organic matter from the lead dioxide electrode surface and restores sensor sensitivity, but also eliminates the need for additional mechanical structures or cleaning solutions, enabling online cleaning.

[0048] The existing technology (DOI 10.1007 / s12274-023-5830-8) mentions a method of directly reducing lead dioxide to lead sulfate on the surface of a lead dioxide electrode using cyclic voltammetry between 0.6V and 1.8V, followed by the oxidation of lead sulfate back to lead dioxide. However, this method is not practical. The main reason is that it requires the use of 1M sulfuric acid. Using concentrated sulfuric acid is user-unfriendly, and in online applications, a concentrated sulfuric acid storage tank must be provided for the sensor, requiring a large amount of solution to clean the detector after use. In contrast, the method of this invention uses the same electrolyte used for online detection of organic matter content in water, eliminating the need for additional reagent tanks. After cleaning the electrode, it can be used directly for testing without the need for special reagents to clean the electrode and detector. Therefore, compared with the existing technology, this invention has the advantages of simple method and mild reagents.

[0049] Experimental results show that, compared with the lead dioxide electrode before cleaning, cleaning the lead dioxide electrode using the cleaning method of the present invention can increase the test sensitivity by more than 6 times.

[0050] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0051] Example 1

[0052] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0053] An electrochemical three-electrode system was constructed using the lead dioxide electrode to be cleaned as the working electrode, the Ag-AgCl electrode (3M KCl) as the reference electrode, and the platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical reduction reaction was carried out in a sodium sulfate solution with a concentration of 2.8 g / L. The working electrode potential was controlled at -0.6 V and the reduction time was 400 s to reduce the lead dioxide on the surface of the lead dioxide electrode to lead sulfate, thus obtaining the electrochemically reduced lead dioxide electrode.

[0054] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0055] An electrochemical three-electrode system was constructed using the electrochemically reduced lead dioxide electrode as the working electrode, the Ag-AgCl electrode (3M KCl) as the reference electrode, and the platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical oxidation reaction was carried out in a sodium sulfate solution with a concentration of 2.8 g / L. The constant potential was controlled at 1.4 V and the oxidation time was 20 s, so that the lead sulfate on the surface of the lead dioxide electrode was oxidized to lead dioxide.

[0056] Product testing:

[0057] An electrochemical sensor based on a lead dioxide electrode, as described in the literature (DOI 10.1007 / s12274-023-5830-8), was used as a detector to detect the sensitivity of both the lead dioxide electrode before cleaning and the lead dioxide electrode after initial organic contamination. Specifically, the detection sensitivity was measured using a coating wastewater (COD 620 mg / L) and Nanhu Lake water (COD 13 mg / L), and the signal difference between the two was used to reflect the detection sensitivity. The results are as follows: Figure 1 As shown, where, Figure 1 Figure A shows the response signal test diagram of the lead dioxide electrode to be cleaned after initial organic contamination to Nanhu Lake water and coating wastewater. Figure 1 Figure B shows the response signal test diagram of the lead dioxide electrode after cleaning in Example 1 to Nanhu Lake water and painting wastewater. The results show that the difference in response signal between the lead dioxide electrode to be cleaned after initial organic contamination and Nanhu Lake water and painting wastewater was 0.2 μA, while the difference in response signal between the cleaned lead dioxide electrode and Nanhu Lake water and painting wastewater was 3.3 μA. The cleaning method of the present invention increased the test signal difference from 0.2 μA to 3.3 μA, significantly improving the test sensitivity.

[0058] Note: The International Union of Pure and Applied Chemistry (IUPAC) defines "analytical sensitivity" as the change in analytical signal caused by a one-unit change in the concentration or content of the analyte. It refers to the slope of the calibration curve (x-axis: concentration, y-axis: measurement signal). The steeper the slope, the higher the "analytical sensitivity." In our system, the COD value changed from 13 mg / L to 620 mg / L, resulting in a difference in current signal of 0.2 μA and 3.3 μA before and after electrode cleaning. According to the IUPAC definition, for the same concentration change, the greater the difference in signal change, the higher the sensitivity of the test method. Therefore, the lead dioxide electrode cleaned using this invention significantly improves the test sensitivity.

[0059] Example 2

[0060] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0061] An electrochemical three-electrode system was constructed using the lead dioxide electrode to be cleaned (same as in Example 1) as the working electrode, the Ag-AgCl electrode (3M KCl) as the reference electrode, and the platinum wire as the counter electrode. An electrochemical reduction reaction was carried out using a sodium sulfate solution with a concentration of 5.0 g / L as the supporting electrolyte. The working electrode potential was controlled at -0.4 V and the reduction time was 200 s to reduce the lead dioxide on the surface of the lead dioxide electrode to lead sulfate, thus obtaining the electrochemically reduced lead dioxide electrode.

[0062] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0063] An electrochemical three-electrode system was constructed using the electrochemically reduced lead dioxide electrode as the working electrode, the Ag-AgCl electrode (3M KCl) as the reference electrode, and the platinum wire as the counter electrode. An electrochemical oxidation reaction was carried out using a 5.0 g / L sodium sulfate solution as the supporting electrolyte solution. The constant potential was controlled at 1.4 V and the oxidation time was 60 s, so that the lead sulfate on the surface of the lead dioxide electrode was oxidized to lead dioxide.

[0064] Product testing:

[0065] The test was conducted according to the test method in Example 1. The results showed that the difference in response signal between the cleaned lead dioxide electrode and the water from Nanhu Lake and the coating wastewater was 1.2 microamps. The cleaning method of the present invention increased the difference in test signal from 0.2 microamps to 1.2 microamps, which significantly improved the test sensitivity.

[0066] Example 3

[0067] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0068] An electrochemical three-electrode system was constructed using the lead dioxide electrode to be cleaned (same as in Example 1) as the working electrode, the Ag-AgCl electrode (3M KCl) as the reference electrode, and the platinum wire as the counter electrode. An electrochemical reduction reaction was carried out using an 8.0 g / L sodium sulfate solution as the supporting electrolyte. The working electrode potential was controlled at -1.0 V and the reduction time was 10 s to reduce the lead dioxide on the surface of the lead dioxide electrode to lead sulfate, thus obtaining the electrochemically reduced lead dioxide electrode.

[0069] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0070] An electrochemical three-electrode system was constructed using the electrochemically reduced lead dioxide electrode as the working electrode, the Ag-AgCl electrode (3M KCl) as the reference electrode, and the platinum wire as the counter electrode. An 8.0 g / L sodium sulfate solution was used as the supporting electrolyte solution to carry out an electrochemical oxidation reaction. The constant potential was controlled at 1.4 V and the oxidation time was 10 s to oxidize the lead sulfate on the surface of the lead dioxide electrode to lead dioxide.

[0071] Product testing:

[0072] The test was conducted according to the test method in Example 1. The results showed that the difference in response signal between the cleaned lead dioxide electrode and the water from Nanhu Lake and the coating wastewater was 3.4 microamps. The cleaning method of the present invention increased the difference in test signal from 0.2 microamps to 3.4 microamps, which significantly improved the test sensitivity.

[0073] Comparative Example 1

[0074] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0075] Implemented according to Example 1, except that the working electrode potential is controlled to be 0.5V.

[0076] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0077] Implemented according to Example 1, except that the control potential is 2.0V.

[0078] Product testing:

[0079] The test was conducted according to the test method in Example 1. The results showed that the difference in response signal between the cleaned lead dioxide electrode and the Nanhu Lake water and the coating wastewater was 0.4 microamps. The cleaning method of Comparative Example 1 changed the difference in test signal from 0.2 microamps to 0.4 microamps, but did not significantly improve the test sensitivity.

[0080] Comparative Example 2

[0081] A) Electrochemical reduction of lead sulfate to form on the electrode surface:

[0082] Implemented according to Example 1, except that the working electrode potential is controlled to be -2.0V.

[0083] B) Lead sulfate on the electrode surface is oxidized to lead dioxide:

[0084] Implemented according to Example 1, except that the control potential is 0.5V.

[0085] Product testing:

[0086] The test was conducted according to the test method in Example 1. The results showed that the difference in response signal between the cleaned lead dioxide electrode and the Nanhu Lake water and the coating wastewater was 0.3 microamps. The cleaning method in Comparative Example 2 changed the difference in test signal from 0.2 microamps to 0.3 microamps, but did not significantly improve the test sensitivity.

[0087] As can be seen from the test results of Comparative Examples 1-2 compared with Example 1, the test results of the lead dioxide electrode treated with Comparative Examples 1-2 are worse. This indicates that the organic matter attached to its surface was not sufficiently removed, thus affecting its test sensitivity. This demonstrates that controlling the specific conditions in steps A) and B) of the method of the present invention can effectively clean the lead dioxide electrode, thereby improving its test results.

[0088] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A method for cleaning a lead dioxide electrode, characterized in that, Includes the following steps: A) Electrochemical reduction of lead sulfate to form on the electrode surface: An electrochemical three-electrode system was constructed using a lead dioxide electrode as the working electrode, an Ag-AgCl electrode as the reference electrode, and a platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical reduction reaction was carried out in a sodium sulfate solution to reduce the lead dioxide on the surface of the lead dioxide electrode to lead sulfate, thus obtaining an electrochemically reduced lead dioxide electrode. The conditions for the electrochemical reduction reaction are: the working electrode potential is -1.0 to -0.4 V, and the reduction time is 10 to 400 s; In step A), the concentration of the sodium sulfate solution is 2.8~8.0 g / L; B) Lead sulfate on the electrode surface is oxidized to lead dioxide: An electrochemical three-electrode system was constructed using the electrochemically reduced lead dioxide electrode as the working electrode, the Ag-AgCl electrode as the reference electrode, and the platinum wire as the counter electrode. Sodium sulfate was used as the supporting electrolyte, and an electrochemical oxidation reaction was carried out in the sodium sulfate solution to oxidize the lead sulfate on the surface of the lead dioxide electrode to lead dioxide. The conditions for the electrochemical oxidation reaction are: constant potential of 1.4V and oxidation time of 10~60s; In step B), the concentration of the sodium sulfate solution is 2.8~8.0 g / L.

2. The cleaning method according to claim 1, characterized in that, In step A), the filling solution in the reference electrode chamber of the Ag-AgCl electrode is a 3M KCl solution.

3. The cleaning method according to claim 1, characterized in that, In step B), the filling solution in the reference electrode chamber of the Ag-AgCl electrode is a 3M KCl solution.

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