Lead plate hydrophobic treatment method based on composite surface modification and application

Abstract

The invention belongs to the technical field of metal surface functionalization treatment and electrochemical industry environmental protection, particularly relates to a lead plate hydrophobic treatment method based on composite surface modification and application, and provides a composite surface modification technology for solving the problem of particulate matter emission caused by high surface hydrophilicity and low bubble separation efficiency in the traditional lead plate electrolysis process. A nano porous layer is generated through anodic oxidation, a directional microgroove is subjected to laser etching for multi-stage micro-nano structure collaborative design, chemical bonding super-hydrophobic modification is achieved through polypyrrole-fluorosilane molecule self-assembly and nano SiO2 compounding, and technological parameters such as anodic oxidation, laser etching and hydrophobic modification are subjected to collaborative optimization; the system integrates the functions of bubble dynamic regulation and control and particulate matter emission reduction, breaks through the bottleneck of the traditional technology, has remarkable advantages in the aspects of efficient emission reduction, long-acting stability, efficiency improvement, low-cost adaptation and the like, and provides an innovative scheme for sustainable development in related fields.

Description

Technical Field

[0001] The invention belongs to the technical field of metal surface functionalization treatment and electrochemical industrial environmental protection, and particularly relates to a lead plate hydrophobic treatment method based on composite surface modification and its application. Background Art

[0002] In industries such as lead-acid battery production and electrolytic metallurgy, the electrochemical reactions during the electrolysis process involve complex material and energy conversion. Taking lead-acid batteries as an example, during the charge and discharge process, lead oxidation occurs at the negative electrode to produce lead ions, while reduction occurs at the positive electrode to convert lead dioxide into lead sulfate. This series of reactions is accompanied by the precipitation of hydrogen (H2) and oxygen (O2) on the electrode surfaces. When these bubbles nucleate, grow, and detach on the lead plate surface, they can trigger a series of secondary problems. In electrolytic metallurgy processes, such as lead electrorefining, the anode undergoes oxidation to release oxygen and the cathode reduces metal ions, similarly resulting in the formation and detachment of bubbles. When bubbles reach the gas-liquid interface, they violently rupture due to surface tension imbalance, instantly generating high-speed microjets and liquid film splashes at speeds of tens of meters per second. Research has shown that the local peak pressures generated by these high-speed microjets can reach hundreds of kilopascals. The splashing liquid film carries lead oxides (such as the highly oxidizing PbO2 and the poorly soluble PbSO4) and components of the electrolyte, such as sulfuric acid, forming particles with a size in the range of PM2.5. 2.5 -PM 10 According to environmental monitoring data, the PM in the air of lead-acid battery production workshops that have not taken effective treatment measures is 2.5 The concentration can reach 10-20 times that of the normal environment, which not only causes serious pollution to the surrounding atmospheric environment, but also causes irreversible damage to the respiratory and nervous systems of operators through long-term exposure. At the same time, the loss of lead-based materials along with the particulate matter reduces the effective substances of the lead-acid battery plates, resulting in a decrease in battery capacity, a decrease in the metal recovery rate of electrolytic metallurgy, and an increase in production costs.

[0003] When addressing the above-mentioned problems, the existing technologies have many defects that need to be solved urgently, which are detailed as follows:

[0004] From the perspective of material surface properties, traditional lead sheets are extremely hydrophilic due to their crystal structure and surface chemical properties, resulting in extremely high surface wettability and a contact angle typically less than 30°. This high hydrophilicity makes it very easy for bubbles to adhere to the surface of the lead sheet. A large number of bubbles aggregate to form a covering layer, which hinders the flow of current and causes uneven current distribution. Studies have found that when the bubble coverage rate on the lead sheet surface exceeds 30%, the electrolysis efficiency will drop by 20%-30%. Moreover, because bubbles have difficulty detaching quickly from hydrophilic surfaces, they will continue to grow to millimeter-scale sizes (generally 2-5 mm). At this point, the probability of bubbles bursting after reaching the gas-liquid interface increases significantly, leading to more electrolytic particulate matter emissions. In terms of surface coating technology, low-surface-energy material coatings such as polypyrrole-fluorosilane-based materials, which are currently widely used, can reduce the wettability of the lead sheet surface to a certain extent. However, under long-term erosion by the electrolyte, the chemical bonds between the coating and the substrate will break due to chemical corrosion and mechanical wear. Active substances in the electrolyte, such as sulfate and hydrogen ions, react chemically with the coating material, destroying its structure. Furthermore, the impact of bubbles during detachment can accelerate their shedding. Furthermore, this type of single hydrophobic coating relies solely on chemical modification, unable to actively regulate its detachment behavior based on bubble growth, making it impossible to precisely control the bubble detachment process.

[0005] From the perspective of micro-nanostructure design, in the existing technology, the hydrophobicity of the micro-nanostructure formed by a single anodization or laser treatment is obviously insufficient. According to the Wenzel model and the Cassie-Baxter model, the hydrophobicity of the material surface depends not only on the surface chemical properties, but is also closely related to the surface microstructure. The micro-nanostructure formed by a single treatment cannot effectively capture air to form an air film due to the lack of a multi-level rough structure, resulting in a contact angle of generally less than 120°. Under the osmotic action of the electrolyte, these micro-nanostructures are filled with liquid and lose their hydrophobic function, which increases the adhesion of the bubbles to the surface and makes them difficult to detach. Moreover, since the multi-level rough structure is not combined with the low surface energy modification, the synergistic effect cannot be fully exerted, and the bubbles cannot be quickly detached at the micron level (<200μm).

[0006] This shows that only when bubbles detach at a relatively small size will the energy and amount of splashing droplets generated by their rupture at the gas-liquid interface be significantly reduced, effectively suppressing the generation of electrolytic particulate matter. Therefore, it is necessary to study a method that combines a porous oxide layer with a microgrooved structure through cross-scale coupling design, combined with chemical modification to form a stable, low-surface-energy superhydrophobic surface, to accelerate bubble desorption, thereby regulating the bubble burst size during electrolysis and achieving the goal of reducing electrolytic particulate matter emissions. Summary of the Invention

[0007] The present invention discloses a lead plate hydrophobic treatment method based on composite surface modification and its application. A multi-level micro-nano hydrophobic structure is constructed on the lead plate surface through a three-step collaborative process. Combining structural design with chemical modification, the method achieves bubble minimization and particle emission reduction.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A method for hydrophobic treatment of lead plates based on composite surface modification comprises the following steps:

[0010] Step a, preparing anodizing electrolyte;

[0011] Step b, constructing a nanoporous layer on the surface of the anode plate by pre-treatment of the anode plate by anodization;

[0012] Step c, ultrasonically cleaning the anode plate having the nanoporous layer on its surface obtained in step b;

[0013] Step d, laser etching the nanoporous layer after ultrasonic cleaning;

[0014] Step e: adsorbing the polypyrrole-fluorosilane-based low surface energy material on the surface of the anode plate obtained in step d, and then performing electronic curing.

[0015] Preferably, in the step a, in the anodizing electrolyte, the mass proportion of phenylphosphonic acid and sulfuric acid is 1-30 wt%, the mass proportion of citric acid is 0.1-5 wt%, and the remaining component is deionized water.

[0016] Preferably, the specific steps of step b are: the anode plate is a lead plate, the lead plate is placed in the anodizing electrolyte prepared in step a, a DC voltage of 10-20V is applied, the reaction temperature is 20-40°C, and the reaction time is 10-60 minutes.

[0017] Preferably, in step c, the cleaning agent for ultrasonic cleaning is acetone, ethanol or deionized water, and the cleaning time is 5-30 minutes.

[0018] Preferably, in step d, the laser processing parameters are set to: energy density 1.5-4 J / cm 2 , scanning speed 50-500mm / s, pulse frequency 10-100kHz; during the laser etching process, inert gas protection is introduced or the processing environment is kept in a vacuum environment, and the oxygen content is ≤5%.

[0019] Preferably, in the step d, a parallel microgroove array is etched on the surface of the nanoporous layer to guide the directional discharge of bubbles.

[0020] Preferably, the specific steps of step e are: immersing the lead plate in a polypyrrole-fluorosilane ethanol solution with a concentration of 1-5wt% for 10-60 minutes to allow the polypyrrole-fluorosilane molecules to be fully adsorbed on the surface of the lead plate; then placing the lead plate under the conditions of an acceleration voltage of 100-300keV and an electron beam dose of 5-100kGy for electronic curing, followed by heat treatment at 120°C for 1 hour, and finally secondary curing at 250°C for 1 hour.

[0021] The invention discloses an application of a hydrophobic treatment method for lead plates based on composite surface modification. The hydrophobic anode plates obtained by the hydrophobic treatment method for lead plates based on composite surface modification are used in the fields of lead-acid battery production and electrolytic metallurgy industry. The method regulates the size and speed of bubbles detaching from the plates during the electrolysis process, suppresses microjets and droplet splashing generated by bubble rupture at the gas-liquid interface, and reduces the emission of electrolytic particulate matter.

[0022] The beneficial effects of the hydrophobic treatment method of a lead plate based on composite surface modification and its application are as follows:

[0023] (1) The present invention significantly reduces the size of bubbles and the probability of them breaking by coordinating the multi-level structure of the anodized nanoporous layer and the nanosecond laser-etched microgrooves. The microgrooves guide the directional migration of bubbles, prompting them to detach from the electrode surface in extremely small sizes, thereby suppressing the generation of particulate matter during the electrolysis process from the source and achieving efficient emission reduction.

[0024] (2) The present invention uses polypyrrole-fluorosilane chemical bonding modification and combines it with a nano-SiO2 enhanced composite coating to give the lead plate excellent superhydrophobic properties; the coating has long-term stability and excellent corrosion resistance, effectively solving the problem of easy shedding of traditional coatings and ensuring that it continues to function in complex electrolytic environments.

[0025] (3) The present invention reduces the "dead zone" formed by bubbles on the electrode surface through the directional microgroove structure, optimizes the current distribution, reduces the local current density fluctuation, and improves the current uniformity, thereby effectively improving the electrolysis efficiency and achieving a dual improvement in environmental protection benefits and production efficiency.

[0026] (4) The present invention blocks electrolyte penetration through the synergistic effect of the porous oxide layer and the chemically bonded coating, thereby enhancing the wear resistance and corrosion resistance of the electrode. Through the synergistic protection of structure and function, the service life of the lead plate is significantly extended, the loss of lead-based materials is reduced, and production costs are saved.

[0027] (5) The process parameters of the technology of the present invention can be flexibly adapted to existing electrolytic cell equipment without the need to modify the core device, greatly reducing the modification cost, showing good process compatibility and industrial feasibility, and providing a practical solution for the green transformation of the electrochemical industry.

[0028] To sum up, the present invention has broken through the technical bottleneck of traditional lead plates in bubble control and particulate matter emission reduction through multi-level micro-nano structure design, chemical bonding modification and coordinated optimization of process parameters, and achieved high-efficiency emission reduction (particulate matter reduction ≥60%), long-term stability (performance maintained >90% after 100 cycles), efficiency improvement (current distribution uniformity improved by ±10%), and has the core advantage of low-cost adaptation to industrial production lines, providing innovative technical support for the sustainable development of lead-acid batteries, electrolytic metallurgy and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a comparison chart of the electrolytic particulate matter emissions from the hydrophobic surface of lead plates modified by the present invention and other different methods.

[0030] Figure 2 This is a comparison chart of bubble detachment diameters on the hydrophobic surface of lead plates modified by the present invention and other different methods.

[0031] Figure 3 Microscopic image of parallel microgrooves in laser-etched oxide layer. DETAILED DESCRIPTION

[0032] The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0033] The following embodiments may be understood as individually expressing a part of a local structure or method of the present invention, or may be understood as a combination of the embodiments to explain the connotation of a larger structure or method of the present invention.

[0034] Example 1

[0035] A method for hydrophobic treatment of lead plates based on composite surface modification comprises the following steps:

[0036] Step a, preparing anodizing electrolyte;

[0037] Step b, constructing a nanoporous layer on the surface of the anode plate by pre-treatment of the anode plate by anodization;

[0038] Step c, ultrasonically cleaning the anode plate having the nanoporous layer on its surface obtained in step b;

[0039] Step d, laser etching the nanoporous layer after ultrasonic cleaning;

[0040] Step e: adsorbing the polypyrrole-fluorosilane-based low surface energy material on the surface of the anode plate obtained in step d, and then performing electronic curing.

[0041] Example 2

[0042] Based on Example 1, this embodiment discloses:

[0043] In the step a, in the anodizing electrolyte, the mass proportion of phenylphosphonic acid and sulfuric acid is 1wt%, the mass proportion of citric acid is 0.1wt%, and the remaining component is deionized water.

[0044] The specific steps of step b are as follows: the anode plate is a lead plate, the lead plate is placed in the anodizing electrolyte prepared in step a, a 10V DC voltage is applied, the reaction temperature is 20°C, and the reaction time is 60 minutes.

[0045] In the step c, the cleaning agent for ultrasonic cleaning is acetone, and the cleaning time is 5 minutes.

[0046] In step d, the laser processing parameters are set to: energy density 1.5 J / cm 2 , scanning speed 50mm / s, pulse frequency 10kHz; during the laser etching process, inert gas protection is introduced or the processing environment is kept in a vacuum environment with an oxygen content ≤5%.

[0047] The specific steps of step e are: immersing the lead plate in a polypyrrole-fluorosilane ethanol solution with a concentration of 1wt% for 10 minutes to allow the polypyrrole-fluorosilane molecules to be fully adsorbed on the surface of the lead plate; then placing the lead plate under the conditions of an acceleration voltage of 100keV and an electron beam dose of 5kGy for electronic curing, then performing a heat treatment at 120°C for 1 hour, and finally performing secondary curing at 250°C for 1 hour.

[0048] Example 3

[0049] Based on Example 1, this embodiment discloses:

[0050] In the step a, in the anodizing electrolyte, the mass proportion of phenylphosphonic acid and sulfuric acid is 30wt%, the mass proportion of citric acid is 5wt%, and the remaining component is deionized water.

[0051] The specific steps of step b are as follows: the anode plate is a lead plate, the lead plate is placed in the anodizing electrolyte prepared in step a, a 20V DC voltage is applied, the reaction temperature is 40°C, and the reaction time is 10 minutes.

[0052] In the step c, the cleaning agent for ultrasonic cleaning is deionized water, and the cleaning time is 30 minutes.

[0053] In step d, the laser processing parameters are set to: energy density 4J / cm 2, scanning speed 500mm / s, pulse frequency 100kHz; during the laser etching process, inert gas protection is introduced or the processing environment is kept in a vacuum environment, and the oxygen content is ≤5%.

[0054] The specific steps of step e are: immersing the lead plate in a polypyrrole-fluorosilane ethanol solution with a concentration of 5wt% for 60 minutes to allow the polypyrrole-fluorosilane molecules to be fully adsorbed on the surface of the lead plate; then placing the lead plate under the conditions of an acceleration voltage of 300keV and an electron beam dose of 100kGy for electronic curing, then performing a heat treatment at 120°C for 1 hour, and finally performing secondary curing at 250°C for 1 hour.

[0055] Example 4

[0056] Based on the above embodiments, this embodiment discloses: in the step a, the mass fraction ratio of phenylphosphonic acid to sulfuric acid in the anodizing electrolyte is 1:2; in the step d, a parallel microgroove array is etched on the surface of the nanoporous layer to guide the directional discharge of bubbles.

[0057] Step a: prepare the solution required for anodizing to prepare for subsequent processing;

[0058] In step b, phenylphosphonic acid / sulfuric acid is used as the main electrolyte to react with the lead plate to produce an oxidation reaction, and citric acid is used as a chelating agent to react with the lead ions to form a complex, thereby regulating the growth of the lead oxide pores and ensuring a uniform distribution of the pores. Under these conditions, a DC voltage is applied to induce an anodic oxidation reaction on the surface of the lead plate to form a porous lead oxide layer. This nanoporous layer not only increases the roughness of the lead plate surface but also provides a good substrate for subsequent micro-nanostructure processing and hydrophobic modification. Its unique pore structure helps to enhance the bonding between the coating and the substrate.

[0059] In step c, the surface of the lead plate obtained in step b is ultrasonically cleaned to effectively remove oil stains, impurities, etc. on the surface of the lead plate, thereby ensuring the accuracy and quality of the laser processing;

[0060] Step d: Nanosecond laser etching of directional microgrooves. This directional microgroove structure can guide the bubbles generated during the electrolysis process. The geometric constraints of the microgrooves allow the bubbles to migrate along the microgrooves during growth, thereby changing the bubble trajectory and paving the way for efficient bubble detachment.

[0061] Step e: The laser-etched lead plate is immersed in a polypyrrole-fluorosilane alcohol solution, and then the lead plate is subjected to an electron beam / thermosetting combined curing treatment to promote a chemical reaction between the silaneoxy groups in the polypyrrole-fluorosilane molecules and the hydroxyl groups on the surface of the lead oxide, forming a chemical bond, and ultimately constructing a super-hydrophobic coating with a thickness of 100-500nm. This coating, by virtue of its low surface energy characteristics and the synergistic effect of the micro-nano structure, gives the lead plate excellent hydrophobic properties, allowing the lead plate surface to effectively repel water molecules, reducing the infiltration of the electrolyte on the surface, and thereby reducing the adhesion of bubbles to the surface.

[0062] Example 5

[0063] Based on the above embodiments, this embodiment discloses an application of a lead plate hydrophobic treatment method based on composite surface modification, specifically: the hydrophobic anode plate obtained by the lead plate hydrophobic treatment method based on composite surface modification is used in the fields of lead-acid battery production and electrolytic metallurgy industry to regulate the size and speed of bubbles detaching from the plate during the electrolysis process, inhibit the microjets and droplet splashing generated by the bubble rupture at the gas-liquid interface, and reduce the emission of electrolytic particulate matter.

[0064] Example 6

[0065] A method for hydrophobic treatment of lead plates based on composite surface modification comprises the following steps:

[0066] The first step is to prepare the anodic oxidation electrolyte. Analytically pure phenylphosphonic acid, sulfuric acid and citric acid are selected as raw materials, and the proportions are strictly based on the mass fraction. Accurately weigh phenylphosphonic acid and sulfuric acid so that their mass fraction in the mixed solution reaches 30wt%; add an appropriate amount of citric acid to control its mass fraction to 5wt%, and the rest is supplemented by deionized water. Transfer the prepared solution to a glass beaker, place it on a constant temperature magnetic stirrer, set the temperature to 25°C, and stir continuously at a speed of 200r / min for 30 minutes. During the stirring process, the magnetic stirrer rotates in the solution to promote the full mixing of phenylphosphonic acid / sulfuric acid, citric acid and water, ensure the consistency of concentration of each part of the solution, and provide a stable electrolyte environment for the subsequent anodic oxidation reaction.

[0067] The second step is anodization pretreatment. An industrial-grade pure lead plate measuring 10 cm × 10 cm × 0.5 cm is selected. Before use, its surface is lightly polished with sandpaper to remove the surface oxide layer and impurities. It is then rinsed with deionized water and dried. The treated lead plate is completely immersed in the prepared electrolyte, and the solution temperature is precisely controlled at 30°C using a water bath. A DC regulated power supply is used as the power supply. The positive terminal of the power supply is connected to the lead plate, and the negative terminal is connected to an inert electrode (such as a platinum electrode). A stable voltage of 15V is applied. Under the influence of the electric field, an anodic oxidation reaction occurs on the surface of the lead plate. The lead atoms lose electrons and are oxidized to lead ions, which then combine with oxygen in the electrolyte to form lead oxide. After the reaction continues for 30 minutes, the lead plate is removed, revealing a uniform, dense, porous lead oxide layer. Scanning electron microscopy (SEM) examination reveals that the oxide layer has a pore size of approximately 150 nm, a thickness of 3 μm, and a porosity of approximately 50%. This porous structure increases the specific surface area of the lead plate and provides more active sites for subsequent surface modification.

[0068] The third step is ultrasonic cleaning. Carefully immerse the lead plate that has completed the anodizing pretreatment in anhydrous ethanol to ensure that the lead plate is completely immersed. Place the container containing the lead plate and ethanol in a 40kHz ultrasonic cleaning machine. The cavitation effect generated when the ultrasonic wave propagates in the liquid can generate a strong impact force on the surface of the lead plate, effectively removing the residual electrolyte, reaction by-products and tiny impurity particles on the surface. The cleaning process lasts for 15 minutes, during which the ethanol solution can be observed to gradually become turbid. After cleaning, use a high-pressure nitrogen gun to blow dry the surface of the lead plate to remove the residual ethanol on the surface, so that the surface of the lead plate remains dry and clean, and prepare for the subsequent laser etching process.

[0069] The fourth step is nanosecond laser etching. A nanosecond pulse laser with a wavelength of 532nm and a pulse width of 10ns is used for processing. Before processing, the various parameters of the laser are precisely debugged: the energy density is set to 2.5J / cm 2, this energy density can ensure the effective etching of the oxide layer while avoiding excessive melting or ablation of the material due to excessive energy; the scanning speed is set to 200mm / s to ensure that the etched microgrooves have clear lines and regular edges; the pulse frequency is adjusted to 50kHz so that the laser pulses can form a continuous and uniform etching effect on the material surface; the spot overlap rate is set to 50% to ensure the integrity and consistency of the etched area. During the processing, the lead plate is placed on the workbench and placed in a nitrogen protection box. By continuously passing high-purity nitrogen, the oxygen content in the box is controlled at ≤3% to prevent oxidation of the material surface during laser processing. Start the laser and etch a parallel microgroove array on the surface of the oxide layer. After etching, observation under an optical microscope shows that the microgroove width is 30μm, the depth is 15μm, and the spacing is 100μm. Further SEM observation revealed that secondary nanopores (diameter of about 80 nm) were formed on the side walls and bottom of the microgrooves, with a surface roughness of Ra≈3 μm. This multi-level micro-nano structure further enhanced the surface roughness of the lead plate, which is conducive to the subsequent adhesion of the hydrophobic coating and the directional guidance of bubbles.

[0070] Step 5: Hydrophobic modification. Prepare a 2wt% polypyrrole-fluorosilane ethanol solution: slowly add a certain amount of polypyrrole-fluorosilane to anhydrous ethanol, use a magnetic stirrer to stir at 300 rpm for 30 minutes to ensure that the polypyrrole-fluorosilane is fully dissolved in the ethanol to form a uniform and transparent solution. Carefully immerse the laser-etched lead plate in the solution, and let it stand for 40 minutes to allow the polypyrrole-fluorosilane molecules to be fully adsorbed on the surface of the lead plate. During this process, the silaneoxy groups in the polypyrrole-fluorosilane molecules undergo hydrolysis and condensation reactions with the hydroxyl groups on the surface of lead oxide to form chemical bonds. After the adsorption is completed, the lead plate is removed from the solution and electronically cured under the conditions of an acceleration voltage of 100-300keV and an electron beam dose of 5-100kGy, followed by a heat treatment at 120°C for 1 hour, and finally a secondary cure at 250°C for 1 hour. The electron beam / high temperature combined curing process promotes further cross-linking and polymerization of polypyrrole-fluorosilane molecules, ultimately forming a super-hydrophobic coating with a thickness of about 300 nm on the surface of the lead plate.

[0071] The electrode plate with a multi-level micro-nano hydrophobic structure constructed by the collaborative process obtained in this example was used in metal smelting electrolysis experiments and surface performance testing to explore its role in reducing particulate matter emissions by regulating bubble size and desorption rate during the electrolysis process, as well as its hydrophobic properties in harsh environments. The specific operations are as follows:

[0072] In a simulated electrolysis environment, the treated lead plate was used as an electrode and placed in a 1M H2SO4 electrolyte. An electric current of 50 mA / cm was applied. 2The electrolysis test was conducted with a current density of 1000 nm. Real-time monitoring using a high-speed camera and a particle concentration detector revealed that the bubble coverage on the lead plate surface was only 12%, with the maximum diameter of the bubble detaching to be 0.5 mm. The electrolysis particle emission concentration was 28 mg / m 3 Compared with untreated lead plates, particulate matter emissions were reduced by 79.3%, fully demonstrating the significant effect of this treatment method in suppressing particulate matter emissions.

[0073] Testing the treated lead plate surface using a contact angle meter revealed a static water contact angle of 158° and a rolling angle of 6°, indicating that water droplets are almost spherical and roll off the surface easily, demonstrating excellent superhydrophobic properties. After immersing the lead plate in a 1M H₂SO₄ solution for 24 hours, the contact angle was measured again to be 152°, with a contact angle decay of only 3.8%, demonstrating that the superhydrophobic coating maintains good stability even in strongly acidic environments.

[0074] Example 7

[0075] The difference from Example 1 is that:

[0076] Compared with Example 6, the secondary curing step is omitted from the coating in the fifth step of this embodiment.

[0077] The electrode plate with multi-level micro-nano hydrophobic structure constructed by the collaborative process obtained in this example is used for metal smelting electrolysis experiment and environmental durability test. The specific steps of the metal smelting electrolysis experiment are the same as those in Example 6. The specific operation of the environmental durability test is as follows:

[0078] The composite coating was tested for wear resistance using a Taber abrasion tester, using a CS-10 abrasive wheel and applying a 1kg load for 1000 cycles. After the test, the contact angle of the coating surface was measured and found to remain above 135°, demonstrating that the composite coating maintains good hydrophobicity and wear resistance even after a certain degree of wear.

[0079] The lead plates coated with the composite coating were immersed in a 1M H2SO4 solution for 24 hours. The coating surface condition was regularly observed and the contact angle was measured. The results showed a contact angle of 145°, a decay rate of less than 8%, and an electrolytic particulate matter emission concentration of 58 mg / m 3 The diameter of the bubble detachment is about 1 mm and there is no visible peeling on the coating surface, which shows that the composite coating has excellent corrosion resistance in a long-term strong acidic environment.

[0080] appendix:

[0081] Comparative Example 1

[0082] The performance test was conducted on a conventional lead plate without any treatment. The contact angle of the surface was measured to be 28° using a contact angle meter, indicating that the surface was highly hydrophilic. 2 Current density), high-speed camera observation revealed that the diameter of the bubbles was about 2.5mm, and a large number of bubbles gathered on the surface of the lead plate, with a surface coverage rate of up to 75%. The electrolytic particulate matter emission concentration was measured using a particle concentration detector, and the result was 135mg / m 3 At the same time, the current density fluctuation range reaches ±30%, which seriously affects the stability and efficiency of the electrolysis process.

[0083] Comparative Example 2

[0084] The performance test was conducted using a single anodized lead plate. Anodization pretreatment was performed according to steps a and b in Example 6 of the present invention to form a porous lead oxide layer, but no subsequent ultrasonic cleaning, nanosecond laser etching, and hydrophobic modification were performed. The lead plate was used for electrolysis testing. Under the same conditions (1M H2SO4 electrolyte, 50mA / cm 2 Current density), observed by high-speed camera, the bubble detachment diameter is about 2mm, the surface coverage rate is as high as 60%, and the particle emission concentration is 110mg / m 3 , the initial static water contact angle is 132°, the rolling angle is 18°, and the current density fluctuation range reaches ±25%. From the perspective of principle, an in-depth analysis shows that the porous lead oxide layer formed by a single anodizing treatment cannot effectively reduce the adhesion between the bubbles and the plate surface due to the lack of synergistic effects of micro-nano structures and hydrophobic surface characteristics, making it difficult to guide the bubbles to detach quickly; and during the electrolysis process, the unstable gas-liquid interface makes it difficult to control particulate matter emissions, and also affects the current stability of the electrolysis process. This shows that anodizing treatment alone cannot effectively guide the detachment of bubbles, the particulate matter emission reduction effect is poor, and the electrolysis process is not stable enough.

[0085] Comparative Example 3

[0086] A lead plate that has undergone traditional fluorosilane hydrophobic modification was selected. The lead plate that has not been anodized and laser etched was directly immersed in a polypyrrole-fluorosilane ethanol solution of the same concentration as in Example 1 of the present invention, and hydrophobic modification was performed under the same immersion time and curing conditions. It was placed in a 1M H2SO4 electrolyte for testing. The initial static water contact angle was 130° and the rolling angle was 15°. During the electrolysis process, the bubble detachment diameter was about 1.8 mm, the surface coverage was about 40%, and the particulate matter emission concentration was 90 mg / m 3. After 24 hours of immersion, the contact angle decayed to 100°, and the coating showed partial peeling. From the perspective of materials science and electrochemical principles, the traditional single hydrophobic coating is only combined with the surface of the lead plate by physical adsorption. Under the long-term scouring of the electrolyte and the chemical action generated by the electrolytic reaction, the bonding force between the coating and the plate gradually weakens, resulting in poor stability of the coating and easy failure. Due to the lack of micro-nano structure to restrain and guide bubbles, a simple hydrophobic coating is difficult to achieve effective suppression of particulate matter emissions.

[0087] The experimental data of the above examples 6, 7 and comparative examples 1-3 are detailed in Figure 1 、 Figure 2 shown.

[0088] To sum up, the present invention has broken through the technical bottleneck of traditional lead plates in bubble control and particulate matter emission reduction through multi-level micro-nanostructure design, chemical bonding modification and coordinated optimization of process parameters, and achieved high-efficiency emission reduction (particulate matter reduction ≥60%), long-term stability (performance maintained >90% after 100 cycles), efficiency improvement (current distribution uniformity improved by ±10%), and has the core advantage of low-cost adaptation to industrial production lines.

[0089] Parts not described in the present invention can be implemented by referring to the existing technology.

[0090] The main working principle of the present invention is:

[0091] The present invention aims to solve the problem of particulate matter emission caused by strong surface hydrophilicity and low bubble detachment efficiency of traditional lead plates during the electrolysis process. The invention proposes a composite surface modification technology, which generates a nanoporous layer through anodization and performs multi-level micro-nanostructure collaborative design through laser etching of directional microgrooves. The chemically bonded super-hydrophobic modification is achieved by utilizing the self-assembly of polypyrrole-fluorosilane molecules and the composite of nano-SiO2. The process parameters such as anodization, laser etching and hydrophobic modification are collaboratively optimized, and the dynamic control of bubbles and the particulate matter emission reduction functions are integrated, breaking through the bottleneck of traditional technology. It has significant advantages in efficient emission reduction, long-term stability, efficiency improvement and low-cost adaptation, and provides innovative solutions for the sustainable development of related fields.

[0092] Those skilled in the art should recognize that the above embodiments are merely intended to illustrate the present application and are not intended to limit the present application. Any appropriate changes and modifications to the above embodiments should fall within the scope of protection of the claims of the present application as long as they are within the spirit of the present application.

Claims

1. A method for hydrophobic treatment of lead plates based on composite surface modification, characterized in that: The steps include: Step a, preparing anodizing electrolyte; Step b, constructing a nanoporous layer on the surface of the anode plate by pre-treatment of the anode plate by anodization; Step c, ultrasonically cleaning the anode plate having the nanoporous layer on its surface obtained in step b; Step d, laser etching the nanoporous layer after ultrasonic cleaning; Step e: adsorbing the polypyrrole-fluorosilane-based low surface energy material on the surface of the anode plate obtained in step d, and then performing electronic curing.

2. A method for treating a grid plate with hydrophobicity based on composite surface modification according to claim 1, characterized in that: In the step a, in the anodizing electrolyte, the mass proportion of phenylphosphonic acid and sulfuric acid is 1-30wt%, the mass proportion of citric acid is 0.1-5wt%, and the remaining component is deionized water.

3. A method for hydrophobic treatment of a grid plate based on composite surface modification according to claim 2, characterized in that: The specific steps of step b are as follows: the anode plate is a lead plate, the lead plate is placed in the anodizing electrolyte prepared in step a, a 10-20V DC voltage is passed, the reaction temperature is 20-40°C, and the reaction time is 10-60 minutes.

4. A method for treating a grid plate with hydrophobicity based on composite surface modification according to claim 3, characterized in that: In the step c, the cleaning agent for ultrasonic cleaning is acetone, ethanol or deionized water, and the cleaning time is 5-30 minutes.

5. A method for treating a grid plate with hydrophobicity based on composite surface modification according to claim 4, characterized in that: In step d, the laser processing parameters are set to: energy density 1.5-4J / cm 2 , scanning speed 50-500mm / s, pulse frequency 10-100kHz; during the laser etching process, inert gas protection is introduced or the processing environment is kept in a vacuum environment, and the oxygen content is ≤5%.

6. A method for treating a grid plate with hydrophobicity based on composite surface modification according to claim 5, characterized in that: In the step d, a parallel microgroove array is etched on the surface of the nanoporous layer to guide the directional discharge of bubbles.

7. A method for treating a grid plate with hydrophobicity based on composite surface modification according to claim 6, characterized in that: The specific steps of step e are: immersing the lead plate in a polypyrrole-fluorosilane ethanol solution with a concentration of 1-5wt% for 10-60 minutes to allow the polypyrrole-fluorosilane molecules to be fully adsorbed on the surface of the lead plate; then placing the lead plate under the conditions of an acceleration voltage of 100-300keV and an electron beam dose of 5-100kGy for electronic curing, then performing a heat treatment at 120°C for 1 hour, and finally performing secondary curing at 250°C for 1 hour.

8. An application of a method for hydrophobic treatment of lead plates based on composite surface modification, characterized by: The hydrophobic anode plates obtained by the hydrophobic treatment method of lead plates based on composite surface modification are used in the production of lead-acid batteries and the electrolytic metallurgical industry to regulate the size and speed of bubbles detaching from the plates during the electrolysis process, inhibit the microjets and droplet splashing caused by bubble rupture at the gas-liquid interface, and reduce the emission of electrolytic particulate matter.

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