Method for degrading aqueous polyacrylic acid emulsion by electrochemical oxidation

Abstract

The application discloses a method for degrading aqueous polyacrylic acid emulsion by electrochemical oxidation, and comprises the following steps: S1, preparing an electrode: graphite sheets are bonded with PTFE resin to prepare graphite sheet electrodes, then the graphite sheet electrodes are immersed in a Fe 3+ solution, taken out after the immersion is completed, carbonized under heating to obtain modified graphite sheet electrodes as anode electrodes; another graphite sheet electrode is directly carbonized under heating to obtain a cathode electrode; S2, adding the polyacrylic acid emulsion to be treated into an electrolyte and adding sodium sulfate; S3, adopting a two-electrode system, taking the modified graphite sheet electrode prepared in the step S1 as a cathode, and inserting the electrode into the electrolyte in the step S2 to perform electrochemical oxidation treatment, so as to degrade the polyacrylic acid emulsion in the electrolyte. The method provided by the application can efficiently degrade the polyacrylic acid, has good current efficiency through electrode performance optimization, is simple in process, environment-friendly, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of polypropylene pollutant treatment technology, and in particular to a method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion. Background Technology

[0002] Traditional methods for treating aqueous polyacrylic acid emulsions, such as physical adsorption, while simple to operate, only adsorb polyacrylic acid onto the surface of the adsorbent without actually degrading it. Subsequent treatment of saturated adsorbents can lead to secondary pollution and is costly. Chemical precipitation has limited removal efficiency for polyacrylic acid because its mechanism is relatively simple and it struggles to completely decompose polyacrylic acid molecules. Furthermore, the use of precipitants may introduce new impurity ions into the water. Biodegradation is highly susceptible to environmental factors such as temperature, pH, and the type and activity of microorganisms. Under unsuitable conditions, degradation efficiency decreases significantly, and the cultivation and acclimation process for microorganisms is complex and time-consuming, making it difficult to quickly handle large volumes of aqueous polyacrylic acid emulsions. In addition, some conventional electrochemical degradation methods often suffer from problems such as short electrode life and low catalytic activity due to improper selection of electrode materials, resulting in low current efficiency and high energy consumption during the degradation process. At the same time, the electrolyte formulation is not optimized enough, which cannot effectively maintain the stability of the reaction system and promote the degradation reaction of polyacrylic acid. Furthermore, the design of the electrolytic cell lacks specificity, and the mass transfer efficiency between electrodes is poor, making it difficult for the degradation reaction to proceed fully, resulting in an unsatisfactory overall degradation effect. Summary of the Invention

[0003] The technical problem this invention aims to solve is to address the shortcomings of the prior art by providing an electrochemical oxidation method for degrading waterborne polyacrylic acid emulsions. This invention improves the catalytic activity and stability of the electrodes and extends their service life by carefully designing the electrode material preparation process, employing a specific graphite film treatment method combined with ferric nitrate impregnation, and other steps. Precise adjustment of the electrolyte composition and pH value enhances the stability of the reaction system and promotes the degradation reaction of polyacrylic acid. Rational design of the electrolytic cell structure and parameters, optimization of electrode spacing and stirring devices, etc., improves the mass transfer efficiency between electrodes. Therefore, under suitable current density and temperature conditions, this method achieves efficient degradation of waterborne polyacrylic acid emulsions, increases the degradation rate of polyacrylic acid and improves current efficiency, reduces energy consumption, and minimizes secondary pollution, providing an economical, efficient, and environmentally friendly solution for the treatment of waterborne polyacrylic acid emulsions.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion, comprising the following steps:

[0005] S1. Electrode preparation:

[0006] A graphite sheet electrode is prepared by bonding graphite sheets with PTFE resin, and then the graphite sheet electrode is subjected to Fe... 3+ The graphite sheet was immersed in a solution, removed after immersion, and then carbonized under heat to obtain a modified graphite sheet electrode, which was used as the anode electrode. Another graphite sheet electrode was directly carbonized under heat to obtain the cathode electrode.

[0007] S2. Add the polyacrylic acid emulsion to be treated to the electrolyte and add sodium sulfate;

[0008] S3. Using a two-electrode system, the modified graphite sheet electrode prepared in step S1 is used as the cathode and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0009] Preferably, Fe in step S1 3+ The solution is ferric nitrate solution.

[0010] Preferably, the concentration of the ferric nitrate solution is 10-40 g / L.

[0011] Preferably, step S1 specifically includes:

[0012] S1-1. The graphite film is crushed into graphite sheets with a diameter of 1-50μm, and then bonded with PTFE resin to form a graphite sheet electrode.

[0013] S1-2. Immerse the graphite sheet electrode in a 10-40 g / L ferric nitrate solution for 6-24 h, remove it and place it in a carbonization furnace at 450-550℃ for 2.5-10 h, cool it to room temperature to obtain a modified graphite sheet electrode, which is used as the anode electrode; separately, take another graphite sheet electrode and carbonize it under direct heating to obtain the cathode electrode.

[0014] Preferably, step S1 specifically includes:

[0015] S1-1. A 25μm thick graphite film is crushed into graphite sheets with a diameter of 1-50μm, and then bonded with PTFE resin to form a graphite sheet electrode.

[0016] S1-2. The graphite sheet electrode is immersed in a 30 g / L ferric nitrate solution for 12 h, then removed and placed in a carbonization furnace at 500 °C for 5 h. After cooling to room temperature, a modified graphite sheet electrode is obtained and used as the anode electrode. Another graphite sheet electrode is carbonized by direct heating to obtain the cathode electrode.

[0017] Preferably, step S2 specifically includes:

[0018] Adjust the pH of the electrolyte to 6-8, then add the polyacrylic acid emulsion to be treated, controlling the concentration of polyacrylic acid in the electrolyte to be 5-20 g / L, then add sodium sulfate, with a concentration of 10-30 g / L, and mix thoroughly.

[0019] Preferably, sodium hydroxide is used to adjust the pH value of the electrolyte in step S2.

[0020] Preferably, step S2 specifically includes:

[0021] Adjust the pH of the electrolyte to 8 with sodium hydroxide, then add the polyacrylic acid emulsion to be treated, controlling the concentration of polyacrylic acid in the electrolyte to be 10 g / L, then add sodium sulfate with a concentration of 20 g / L, and mix thoroughly.

[0022] Preferably, step S3 specifically includes:

[0023] The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0024] During the treatment process, stirring is maintained, and the current density is 10-50 mA / cm². 2 The processing temperature is controlled between 25-40℃.

[0025] Preferably, step S3 specifically includes:

[0026] The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0027] The distance between the anode and cathode electrodes was maintained at 5 cm, the stirring speed was maintained at 100 r / min, and the current density was 15 mA / cm². 2 The processing temperature is controlled at 40℃, and the processing time is 3 hours.

[0028] The beneficial effects of this invention are:

[0029] This invention provides a method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion, which has at least the following advantages:

[0030] 1. Highly Efficient Degradation Performance: This invention employs a meticulously designed electrode material preparation process, utilizing a specific graphite film treatment method to pulverize a 25μm thick graphite film into 1-50μm graphite sheets, which are then bonded to PTFE resin. The anode is obtained through ferric nitrate impregnation and carbonization. Furthermore, optimized electrolyte composition (e.g., determining the polyacrylic acid concentration to be 10g / L and adding sodium sulfate to enhance conductivity) and precisely controlled electrochemical reaction parameters (e.g., appropriate current density, pH value, and temperature) significantly improve the degradation rate of polyacrylic acid. For example, in Example 6, the degradation rate reaches 92%, a significant improvement compared to the low degradation efficiency of conventional treatment methods in the prior art. This enables more effective removal of organic pollutants from aqueous polyacrylic acid emulsions, achieving highly efficient degradation.

[0031] 2. Good current efficiency: This is achieved through proper formulation of the electrolyte components, such as adding sodium sulfate to enhance conductivity, and precise control of reaction conditions. This includes the improvement of electrode activity through the ferric nitrate impregnation step in electrode material preparation, as well as the control of current density (e.g., determining 10-50 mA / cm²). 2 The range is preferably 15 mA / cm. 2 Precise control of temperature (25-40℃, preferably 40℃) and pH value (6-8) reduces unnecessary power loss and improves current efficiency. For example, in Example 11, the current efficiency can reach 68%. Compared to the low current efficiency caused by improper electrode material selection or unreasonable reaction conditions in existing technologies, this invention effectively reduces energy consumption and allows for more efficient utilization of electrical energy.

[0032] 3. Simple and environmentally friendly process: The entire process mainly revolves around several key steps, including electrode material preparation, electrolyte adjustment, electrolytic cell design and electrochemical reaction, and post-treatment. The operation is relatively simple. Furthermore, by rationally controlling the reaction conditions, side reactions are reduced, avoiding problems such as the introduction of new impurity ions in traditional chemical precipitation methods or secondary pollution from adsorption methods. This meets environmental protection requirements and is conducive to large-scale application in the treatment of water-based polyacrylic acid emulsions, reducing negative environmental impacts and promoting sustainable development.

[0033] 4. Electrode Performance Optimization: Special electrode material preparation methods enable electrodes to possess higher catalytic activity and stability, extending their service life. For example, anodes impregnated with ferric nitrate exhibit better performance in the reaction, reducing the need for frequent electrode replacements due to electrode wear, lowering operating costs, and improving the overall economy and stability of the process. This is an advantage that is difficult to achieve with insufficient electrode performance in existing technologies. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0035] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0037] This invention provides a method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion, characterized by comprising the following steps:

[0038] S1. Electrode preparation:

[0039] A graphite sheet electrode is prepared by bonding graphite sheets with PTFE resin, and then the graphite sheet electrode is subjected to Fe... 3+ The graphite sheet was immersed in a solution, removed after immersion, and then carbonized under heat to obtain a modified graphite sheet electrode, which was used as the anode electrode. Another graphite sheet electrode was directly carbonized under heat to obtain the cathode electrode.

[0040] S2. Add the polyacrylic acid emulsion to be treated to the electrolyte and add sodium sulfate;

[0041] S3. Using a two-electrode system, the modified graphite sheet electrode prepared in step S1 is used as the cathode and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0042] In a preferred embodiment, Fe in step S1 3+ The solution is ferric nitrate solution.

[0043] In a preferred embodiment, the concentration of the ferric nitrate solution is 10-40 g / L.

[0044] In a preferred embodiment, step S1 specifically comprises:

[0045] S1-1. The graphite film is crushed into graphite sheets with a diameter of 1-50μm, and then bonded with PTFE resin to form a graphite sheet electrode.

[0046] S1-2. Immerse the graphite sheet electrode in a 10-40 g / L ferric nitrate solution for 6-24 h, remove it and place it in a carbonization furnace at 450-550℃ for 2.5-10 h, cool it to room temperature to obtain a modified graphite sheet electrode, which is used as the anode electrode; separately, take another graphite sheet electrode and carbonize it under direct heating to obtain the cathode electrode.

[0047] In a preferred embodiment, step S1 specifically comprises:

[0048] S1-1. A 25μm thick graphite film is crushed into graphite sheets with a diameter of 1-50μm, and then bonded with PTFE resin to form a graphite sheet electrode.

[0049] S1-2. The graphite sheet electrode is immersed in a 30 g / L ferric nitrate solution for 12 h, then removed and placed in a carbonization furnace at 500 °C for 5 h. After cooling to room temperature, a modified graphite sheet electrode is obtained and used as the anode electrode. Another graphite sheet electrode is carbonized by direct heating to obtain the cathode electrode.

[0050] PTFE resin possesses excellent chemical stability and high-temperature resistance, enhancing the overall performance of the electrode and preventing corrosion during the reaction process. The purpose of impregnation with ferric nitrate solution is to introduce iron elements onto the graphite sheet surface. During subsequent carbonization, the iron elements act as a catalyst, improving the electrocatalytic activity of the electrode.

[0051] In a preferred embodiment, step S2 specifically involves:

[0052] Adjust the pH of the electrolyte to 6-8, then add the polyacrylic acid emulsion to be treated, controlling the concentration of polyacrylic acid in the electrolyte to be 5-20 g / L, then add sodium sulfate, with a concentration of 10-30 g / L, and mix thoroughly.

[0053] When the pH value of the electrolyte is in the range of 6-8, the chemical environment of the electrolyte is relatively stable, which is conducive to the degradation reaction of polyacrylic acid and can reduce electrode corrosion.

[0054] The concentration of polyacrylic acid in the electrolyte is determined by a comprehensive consideration of factors such as reaction rate, degradation effect, and cost. At this concentration, the degradation effect can be guaranteed while making the entire reaction system more economical and efficient.

[0055] The role of sodium sulfate is to enhance the conductivity of the electrolyte, reduce the resistance during the reaction process, thereby improving current efficiency and promoting the degradation reaction of polyacrylic acid.

[0056] In a preferred embodiment, sodium hydroxide is used to adjust the pH value of the electrolyte in step S2.

[0057] In a preferred embodiment, step S2 specifically involves:

[0058] Adjust the pH of the electrolyte to 8 with sodium hydroxide, then add the polyacrylic acid emulsion to be treated, controlling the concentration of polyacrylic acid in the electrolyte to be 10 g / L, then add sodium sulfate with a concentration of 20 g / L, and mix thoroughly.

[0059] In a preferred embodiment, step S3 specifically involves:

[0060] The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0061] During the treatment process, stirring is maintained, and the current density is 10-50 mA / cm². 2 The processing temperature is controlled between 25-40℃.

[0062] In a preferred embodiment, step S3 specifically involves:

[0063] The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0064] The distance between the anode and cathode electrodes was maintained at 5 cm, the stirring speed was maintained at 100 r / min, and the current density was 15 mA / cm². 2 The processing temperature is controlled at 40℃, and the processing time is 3 hours.

[0065] The distance between the anode and cathode is maintained at 5 cm. This electrode spacing design ensures sufficient electric field strength while facilitating the transfer of matter between the electrodes, avoiding the risk of short circuits due to too small a spacing or the problem of low mass transfer efficiency due to too large a spacing.

[0066] The stirring device serves to ensure uniform mixing of the electrolyte within the electrolytic cell, guaranteeing sufficient contact between the reactants and the electrode surfaces, thereby improving the reaction rate and degradation efficiency. Simultaneously, it connects to a DC power supply to provide electrical energy for the electrochemical reaction.

[0067] The current density is adjusted according to actual needs, and is generally controlled between 10-50 mA / cm². 2 Within this current density range, the reaction can proceed effectively, avoiding problems such as excessively slow reaction rates due to too low a current density or increased side reactions and electrode wear due to too high a current density. A current density of 30 mA / cm² is preferred. 2 .

[0068] Adjusting the pH to neutral or slightly alkaline (pH 6-8) is beneficial for improving the degradation rate of organic matter. Within this pH range, the ionization state of polyacrylic acid molecules is more suitable, making them more likely to undergo oxidation reactions and be degraded on the electrode surface.

[0069] The reaction temperature should be maintained between 25-40℃. Excessive temperature will accelerate the corrosion of the electrode material, affecting the electrode's lifespan and the stability of the reaction; excessively low temperature will reduce the reaction rate. The preferred reaction temperature is 30℃, at which a relatively ideal reaction rate can be obtained while ensuring electrode lifespan.

[0070] This invention has at least the following improvements:

[0071] 1. Preparation of Specialized Electrode Materials: A 25μm thick graphite film is pulverized into 1-50μm graphite sheets, bonded with PTFE resin, and then impregnated with ferric nitrate at a specific concentration (preferably 30g / L) and carbonized at 500℃ to prepare the anode. In this process, controlling the graphite sheet diameter range provides a larger specific surface area, ferric nitrate impregnation introduces catalytically active elements, and carbonization enhances electrode stability and conductivity. These factors work together to improve the electrode's catalytic activity and lifespan, overcoming the problems of low catalytic activity and short lifespan in existing technologies. This is one of the key factors in achieving high-efficiency degradation and good current efficiency.

[0072] 2. Precise Electrolyte Control: The polyacrylic acid concentration in the electrolyte is precisely set to 10 g / L. The pH value is adjusted to 6-8 with sodium hydroxide, and sodium sulfate is added as an additive. The determined polyacrylic acid concentration balances degradation efficiency and cost, the suitable pH range ensures reaction stability and degradation efficiency, and sodium sulfate enhances conductivity. These factors synergistically optimize the chemical environment of the reaction system, promoting the degradation reaction of polyacrylic acid and solving the problem of low reaction efficiency caused by poor electrolyte formulation in existing technologies.

[0073] 3. Optimized electrolytic cell design and reaction condition control: A two-electrode system is adopted, maintaining a 5cm distance between the anode and cathode, equipped with a stirring device with specific parameters (3cm diameter, 100r / min rotation speed), and the current density (10-50mA / cm²) is reasonably controlled. 2 15mA / cm is preferred 2 The electrode spacing and stirring device parameters ensure the efficiency of mass transfer between electrodes. The appropriate current density and temperature range avoid problems such as increased side reactions, aggravated electrode wear, and excessively low reaction rates, enabling the entire electrochemical reaction to proceed efficiently and stably. This effectively improves the unsatisfactory degradation effect caused by the lack of targeted design of the electrolytic cell and improper control of reaction conditions in the existing technology.

[0074] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0075] Example 1

[0076] A method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion includes the following steps:

[0077] S1. Electrode material preparation:

[0078] S1-1. A 25μm thick graphite film (SDKFTR25, Jiangsu Sidike) is pulverized into 1-50μm graphite sheets using a pulverizer (Changzhou Hongshi Drying Technology, FS-124), and then bonded with PTFE resin using conventional processes to form a 10mm (diameter) * 10cm (length) graphite sheet electrode.

[0079] Mass ratio:

[0080] The mass ratio of graphite sheets to PTFE resin is 7:3. This ratio ensures that the electrode has both sufficient conductivity and good mechanical strength and corrosion resistance.

[0081] Adhesion process:

[0082] A 25μm thick graphite film (model SDKFTR25, supplier Jiangsu Sidike) was pulverized into graphite flakes with a diameter between 1-50μm using a pulverizer (model FS-124, supplier Changzhou Hongshi Drying Technology).

[0083] Mix the pulverized graphite flakes and PTFE resin powder evenly according to the above mass ratio.

[0084] Add an appropriate amount of deionized water to the mixture as a wetting agent to help the mixture adhere better.

[0085] The mixed materials are placed into a mold and pressed under certain pressure to form a cylindrical structure with a diameter of 10mm and a length of 10cm.

[0086] The pressed sample is placed in an oven and dried at around 100°C for several hours to remove excess moisture or solvent and ensure that the PTFE resin is fully cured to obtain a graphite sheet electrode.

[0087] S1-2. The graphite sheet electrode was immersed in a 20 g / L ferric nitrate (Chinese medicine, 99% purity) solution for 12 h, then removed and placed in a carbonization furnace at 500 °C for 5 h, and cooled to room temperature to obtain a modified graphite sheet electrode, which was used as the anode electrode; another graphite sheet electrode was directly placed in a carbonization furnace at 500 °C for 5 h (i.e., without immersion in the ferric nitrate solution), and cooled to room temperature to obtain the cathode electrode;

[0088] Anode electrode:

[0089] The graphite sheet electrode prepared in S1-1 was immersed in a 20 g / L ferric nitrate solution (Sinopharm Group, purity 99%) for 12 hours to allow ferric nitrate to be adsorbed on the surface of the graphite sheet.

[0090] After impregnation, the electrode is removed and cleaned with deionized water. It is then placed in a carbonization furnace and heated to 500°C at a rate of 5°C / min under nitrogen protection. The temperature is then maintained at this temperature for 5 hours for heat treatment.

[0091] After processing, the material is allowed to cool naturally to room temperature, resulting in a modified graphite sheet electrode, which is then used as the anode electrode.

[0092] Cathode electrode:

[0093] Another graphite sheet electrode that has not been impregnated with ferric nitrate solution was placed directly into the carbonization furnace and heat-treated under the same conditions (i.e., 500℃ for 5 hours).

[0094] After cooling to room temperature, an unmodified graphite sheet electrode is obtained, which is used as the cathode electrode.

[0095] S2, Electrolyte Adjustment:

[0096] Adjust the pH of the electrolyte to 8 using sodium hydroxide (national pharmaceutical company, 99% purity), then add polyacrylic acid (SDK-08, produced by Jiangsu Sidike) to control the concentration of polyacrylic acid in the electrolyte to 10 g / L, and then add sodium sulfate as an additive with a concentration of 20 g / L, and mix thoroughly.

[0097] Electrolyte main components:

[0098] The main component of the electrolyte is deionized water, which serves as a solvent to provide the reaction medium.

[0099] Specific components:

[0100] Deionized water: as a solvent, it provides the liquid environment required for electrochemical reactions.

[0101] Sodium hydroxide (NaOH): Used to adjust the pH of the electrolyte to 8. The product selected is manufactured by Sinopharm Group and has a purity of 99%.

[0102] Polyacrylic acid (PAA): Model SDK-08, manufactured by Jiangsu Sidike, with its concentration in the electrolyte controlled at 10g / L.

[0103] Sodium sulfate (Na2SO4): As a supporting electrolyte, it enhances the conductivity of the solution, helps stabilize the current density, and promotes electrochemical reactions. The product selected is manufactured by Sinopharm Group and has a purity of 99%.

[0104] Sodium sulfate concentration values:

[0105] The specific concentration of sodium sulfate chosen is 20 g / L. This concentration effectively improves the conductivity of the solution without causing excessive salt concentration, thus avoiding corrosion of equipment or increased subsequent processing costs.

[0106] S3, Electrolysis reaction:

[0107] The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

[0108] The anode and cathode were kept 5 cm apart, and the process was maintained with stirring at 100 r / min (stirring device diameter 3 cm) and a current density of 10 mA / cm². 2 The processing temperature is controlled at 25℃.

[0109] Processing result:

[0110] After 3 hours of treatment, the degradation rate and current efficiency of polyacrylic acid were measured by HPLC. The results showed that the degradation rate of polyacrylic acid reached 65%, and the current efficiency was 40%.

[0111] Example 2

[0112] Electrode material preparation: similar to Example 1, except that the concentration of ferric nitrate is 30 g / L.

[0113] Electrolyte adjustment: Same as in Example 1.

[0114] Electrolysis reaction: conditions are the same as in Example 1.

[0115] Treatment results: Degradation rate 85%, current efficiency 60%.

[0116] Example 3

[0117] Electrode material preparation: The concentration of ferric nitrate was 50 g / L, and the rest was the same as in Example 1.

[0118] Electrolyte adjustment: Same as in Example 1.

[0119] Electrolysis reaction: Same as in Example 1.

[0120] Treatment results: Degradation rate 75%, current efficiency 50%.

[0121] Example 4

[0122] Electrode material preparation: similar to Example 2, except that the concentration of ferric nitrate is 30 g / L.

[0123] Electrolyte adjustment: Same as in Example 1.

[0124] Electrolysis reaction: Two-electrode system, electrode distance 5cm, stirring device (diameter 3cm, rotation speed 100r / min), current density 30mA / cm² 2 The reaction temperature is 30℃.

[0125] Results: HPLC analysis showed a polyacrylic acid degradation rate of 85% and a current efficiency of 60%.

[0126] Example 5

[0127] Electrode material preparation: Same as in Example 1.

[0128] Electrolyte adjustment: Same as in Example 1.

[0129] Electrolysis reaction: The conditions are the same as in Example 1, except that the reaction temperature is increased to 35°C.

[0130] Treatment results: Degradation rate 88%, current efficiency 62%.

[0131] Example 6

[0132] Electrode material preparation: Same as in Example 1.

[0133] Electrolyte adjustment: Same as in Example 1.

[0134] Electrolysis reaction: The conditions are the same as in Example 1, but the reaction temperature is 40°C.

[0135] Treatment results: Degradation rate 92%, current efficiency 65%.

[0136] Example 7

[0137] Electrode material preparation: Same as in Example 1.

[0138] Electrolyte adjustment: Same as in Example 1.

[0139] Electrolysis reaction: conditions are the same as in Example 3, reaction temperature 45℃.

[0140] Treatment results: Degradation rate 89%, current efficiency 61%.

[0141] Example 8

[0142] Electrode material preparation: Same as in Example 1.

[0143] Electrolyte adjustment: Same as in Example 1.

[0144] Electrolysis reaction: conditions are the same as in Example 1, reaction temperature 50℃.

[0145] Treatment results: Degradation rate 86%, current efficiency 58%.

[0146] A comparison of Examples 4-8 shows that, based on Example 2, the polyacrylic acid degradation rate and current efficiency are best when the reaction temperature is 40°C.

[0147] Example 9

[0148] Electrode material preparation: Same as in Example 6.

[0149] Electrolyte adjustment: Same as in Example 6.

[0150] Electrolysis reaction: Two-electrode system, electrode distance 5cm, stirring device (diameter 3cm, rotation speed 100r / min), current density 5mA / cm² 2 The reaction temperature is 40℃.

[0151] Results: HPLC analysis showed a polyacrylic acid degradation rate of 75% and a current efficiency of 45%.

[0152] Example 10

[0153] Electrode material preparation: Same as in Example 6.

[0154] Electrolyte adjustment: Same as in Example 6.

[0155] Electrolysis reaction: conditions same as in Example 6, current density 10 mA / cm² 2 .

[0156] Treatment results: Degradation rate 80%, current efficiency 55%.

[0157] Example 11

[0158] Electrode material preparation: Same as in Example 6.

[0159] Electrolyte adjustment: Same as in Example 6.

[0160] Electrolysis reaction: conditions same as in Example 6, current density 15 mA / cm² 2 .

[0161] Treatment results: Degradation rate 90%, current efficiency 68%.

[0162] Example 12

[0163] Electrode material preparation: Same as in Example 6.

[0164] Electrolyte adjustment: Same as in Example 6.

[0165] Electrolysis reaction: conditions same as in Example 6, current density 25 mA / cm² 2 .

[0166] Treatment results: Degradation rate 85%, current efficiency 58%.

[0167] A comparison of Examples 9-12 shows that, based on Example 6, the current density is 15 mA / cm². 2 At that time, the degradation rate of polyacrylic acid and the current efficiency reached a relatively good level.

[0168] In summary, through the study of multiple sets of embodiments, the optimal values ​​for the ferric nitrate concentration in this invention are determined to be 30 g / L, a reaction temperature of 40 °C, and a current density of 15 mA / cm². 2 With the synergistic effect of electrode material preparation, electrolyte adjustment, electrolytic cell design and electrochemical reaction, the degradation rate of polyacrylic acid and current efficiency of water-based polyacrylic acid emulsion by electrochemical oxidation can achieve relatively better results, which are significantly better than other parameter combinations, demonstrating the effectiveness and advancement of the technical solution of this invention.

[0169] The reaction conditions and processing results of the examples are summarized in Table 1 below:

[0170] Table 1

[0171]

[0172]

[0173] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion, characterized in that, Includes the following steps: S1. Electrode preparation: Graphite film was pulverized into graphite flakes with a diameter of 1-50 μm, then bonded with PTFE resin to prepare graphite sheet electrodes. These graphite sheet electrodes were then subjected to Fe... 3+ The graphite sheet was immersed in a solution, removed after immersion, and then carbonized under heat to obtain a modified graphite sheet electrode, which was used as the anode electrode. Another graphite sheet electrode was directly carbonized under heat to obtain the cathode electrode. S2. Add the polyacrylic acid emulsion to be treated to the electrolyte and add sodium sulfate; S3. Combine the anode and cathode electrodes prepared in step S1 into a two-electrode system, and insert it into the electrolyte of step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte.

2. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 1, characterized in that, Fe in step S1 3+ The solution is ferric nitrate solution.

3. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 2, characterized in that, The concentration of ferric nitrate solution is 10-40 g / L.

4. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 1, characterized in that, Step S1 is as follows: S1-1. The graphite film is crushed into graphite sheets with a diameter of 1-50μm, and then bonded with PTFE resin to form a graphite sheet electrode. S1-2. Immerse the graphite sheet electrode in a 10-40 g / L ferric nitrate solution for 6-24 h, remove it and place it in a carbonization furnace at 450-550℃ for 2.5-10 h, cool it to room temperature to obtain a modified graphite sheet electrode, which is used as the anode electrode; separately, take another graphite sheet electrode and carbonize it under direct heating to obtain the cathode electrode.

5. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 4, characterized in that, Step S1 is as follows: S1-1. A 25μm thick graphite film is crushed into graphite sheets with a diameter of 1-50μm, and then bonded with PTFE resin to form a graphite sheet electrode. S1-2. The graphite sheet electrode is immersed in a 30 g / L ferric nitrate solution for 12 h, then removed and placed in a carbonization furnace at 500 °C for 5 h. After cooling to room temperature, a modified graphite sheet electrode is obtained and used as the anode electrode. Another graphite sheet electrode is carbonized by direct heating to obtain the cathode electrode.

6. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 1, characterized in that, Step S2 is as follows: Adjust the pH of the electrolyte to 6-8, then add the polyacrylic acid emulsion to be treated, controlling the concentration of polyacrylic acid in the electrolyte to be 5-20 g / L, then add sodium sulfate, with a concentration of 10-30 g / L, and mix thoroughly.

7. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 6, characterized in that, In step S2, sodium hydroxide is used to adjust the pH value of the electrolyte.

8. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 7, characterized in that, Step S2 is as follows: Adjust the pH of the electrolyte to 8 with sodium hydroxide, then add the polyacrylic acid emulsion to be treated, controlling the concentration of polyacrylic acid in the electrolyte to be 10 g / L, then add sodium sulfate with a concentration of 20 g / L, and mix thoroughly.

9. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 1, characterized in that, Step S3 is as follows: The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte. During the treatment process, stirring is maintained, the current density is 10-50 mA / cm², and the treatment temperature is controlled at 25-40℃.

10. The method for electrochemical oxidation degradation of aqueous polyacrylic acid emulsion according to claim 9, characterized in that, Step S3 is as follows: The anode and cathode electrodes prepared in step S1 are combined into a two-electrode system and inserted into the electrolyte in step S2 for electrochemical oxidation treatment to degrade the polyacrylic acid emulsion in the electrolyte. The distance between the anode and cathode electrodes was maintained at 5 cm, the stirring speed was maintained at 100 r / min, the current density was 15 mA / cm², the treatment temperature was controlled at 40℃, and the treatment time was 3 h.

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