Preparation method and application of curtain type aeration electrode capable of efficiently producing hydrogen peroxide

Abstract

The invention relates to the technical field of electrochemistry, in particular to a preparation method and application of a curtain type aeration electrode capable of efficiently producing hydrogen peroxide, and the preparation method comprises the following steps: cutting a conductive material into the same length, putting the cut conductive material into a pretreatment solution for ultrasonic cleaning, then putting the cut conductive material into deionized water for ultrasonic cleaning, and drying to obtain a pretreated conductive material; inserting a support material into the pretreated conductive material to obtain a support conductive material; winding and fixing a supporting conductive material outside the hydrophobic membrane material to obtain an aeration electrode strip; and sequentially connecting the plurality of aeration electrode strips with the membrane shell assembly to obtain the curtain type aeration electrode. According to the preparation method and application of the curtain type aeration electrode for efficiently producing hydrogen peroxide, the curtain type aeration electrode can efficiently utilize oxygen to efficiently produce H2O2 at low energy consumption, the mass transfer effect is good, and the oxygen utilization rate is high.

Description

Technical Field

[0001] The invention relates to the field of electrochemical technology, and in particular to a preparation method and application of a curtain aeration electrode for efficiently producing hydrogen peroxide. Background Art

[0002] Electro-Fenton can continuously generate H2O2 in situ at the cathode through the two-electron reduction of oxygen (ORR), which reduces the risk of transporting and storing H2O2 in traditional Fenton to a certain extent. Therefore, it plays an increasingly important role in the treatment of industrial wastewater. However, the strength of the cathode's ability to electrosynthesize H2O2 has always been an important factor limiting this process. To solve this problem, on the one hand, the cathode surface can be modified, or different catalysts can be loaded on the cathode to enhance the electrochemical activity of the cathode surface, strengthen the cathode's ability to capture oxygen, and thus enhance the online generation of H2O2. However, in the above-mentioned studies, the cathode modification and catalyst preparation process are complicated, the metal catalyst is expensive, and there is a potential risk of metal leaching causing water pollution during the reaction.

[0003] On the other hand, the cathode electrosynthesis of H2O2 can be enhanced by improving oxygen mass transfer and increasing the dissolved oxygen concentration in the solution. This is a safe and efficient method. Some researchers have designed a pressurized jet aerator based on the Venturi effect. This design has increased the oxygen concentration of the system to a certain extent, but to achieve efficient electrogeneration of H2O2, it is necessary to increase the pressure of the reflux liquid, which undoubtedly increases the overall energy consumption of the system. Later, some researchers used submerged aeration, and O2 was dispersed into the liquid phase in the form of microbubbles through the membrane pores, which effectively increased the concentration of dissolved oxygen in the solution. However, the H2O2 generation efficiency was limited by the mass transfer distance, and some oxygen failed to reach the electrode surface to undergo oxygen reduction reaction. The high aeration volume also caused energy consumption problems, which also hindered its further promotion and application. Summary of the invention

[0004] The purpose of the present invention is to provide a preparation method and application of a curtain aeration electrode for efficiently producing hydrogen peroxide, which uses a hollow hydrophobic membrane material coupled with carbon felt as an aeration electrode, can efficiently utilize oxygen to efficiently produce H2O2 under low energy consumption, and is safe and easy to operate.

[0005] To achieve the above object, the present invention provides a method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide, comprising the following steps: S1, cutting the conductive material into the same length and placing it in a pretreatment solution for ultrasonic cleaning, then placing it in deionized water for ultrasonic cleaning, and drying to obtain a pretreated conductive material; S2, inserting a supporting material into the cut conductive material obtained in S1 to obtain a supporting conductive material; S3, winding and fixing the supporting conductive material in S2 on the outside of the hydrophobic membrane material to obtain an aeration electrode strip; S4. Connecting several aeration electrode strips obtained in S3 to the membrane shell assembly in sequence to obtain a curtain aeration electrode.

[0006] Preferably, the conductive material includes one or more of carbon felt and plastic conductive material.

[0007] Preferably, in S1, the pretreatment solution is ethanol and water mixed in a volume ratio of 1-3:1, the drying temperature is 60-100° C., and the drying time is 0.5-3 h.

[0008] Preferably, in S2, the supporting material is a conductive wire, and the conductive wire includes one or more of a titanium wire and a nickel wire.

[0009] Preferably, in S3, the hydrophobic membrane material is a hollow hydrophobic membrane material, and the winding line density of the supporting conductive material is 1-2 g / m.

[0010] The present invention uses a hollow hydrophobic membrane material for aeration, and utilizes surface micropores to perform microbubble aeration at a low aeration rate. The generated submicron bubbles have a large specific surface area, and can provide sufficient O2 for the oxygen reduction reaction at a lower aeration rate, effectively reducing the overall energy consumption.

[0011] Preferably, the hollow hydrophobic membrane material includes one or more of a hollow polytetrafluoroethylene fiber hydrophobic membrane, a hollow polyvinylidene fluoride fiber hydrophobic membrane, and a hollow polypropylene fiber hydrophobic membrane.

[0012] Preferably, in S4, the membrane shell assembly includes a membrane shell base and a membrane shell air inlet top cover, the membrane shell base and the membrane shell air inlet top cover are connected by a hydrophobic membrane material, and the hydrophobic membrane material is in communication with the membrane shell air inlet top cover.

[0013] The curtain aeration electrode prepared by the above-mentioned method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide is used in a system for efficiently producing hydrogen peroxide.

[0014] Preferably, the efficient hydrogen peroxide production system comprises an electrolysis unit, an oxygen supply unit and a stirring unit, the curtain aeration electrode of the electrolysis unit is connected to the oxygen tank of the oxygen supply unit, and the magnetic rotor of the stirring unit is located in the electrolysis cell of the electrolysis unit.

[0015] Preferably, an anode assembly is provided in the electrolytic cell of the electrolytic unit, and the curtain aeration electrode and the anode assembly are electrically connected to the current and voltage meter respectively.

[0016] Preferably, the oxygen tank of the oxygen supply unit is connected to the aeration electrode through an oxygen supply pipeline, a gas flow meter is provided on the oxygen supply pipeline, and an oxygen pressure gauge is provided on the oxygen tank.

[0017] Therefore, the present invention adopts the above-mentioned preparation method and application of the curtain aeration electrode for efficiently producing hydrogen peroxide, and its beneficial effects are: 1. The preparation method provided by the present invention is simple to operate and does not require expensive modified electrodes and complex reaction units, thereby reducing production costs. The hollow fiber hydrophobic membrane used has a high porosity and a large specific surface area, has a good aeration effect and is highly efficient and energy-saving, and exhibits excellent performance in enhancing the transfer rate of gas molecules at the gas-liquid interface; 2. The curtain aeration electrode provided by the present invention is obtained by winding a hollow hydrophobic membrane material with carbon felt, which can efficiently utilize oxygen to efficiently produce H2O2 at low energy consumption, has good mass transfer effect, high oxygen utilization rate, high current efficiency, and is safe and easy to operate; 3. The curtain aeration electrode provided by the present invention avoids the disadvantage of the existing electro-Fenton process that additional H2O2 needs to be added, and reduces the potential safety hazards in transportation and storage.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a curtain-type aeration electrode for efficiently producing hydrogen peroxide according to the present invention; Figure 2 is a schematic diagram of a highly efficient hydrogen peroxide production system of the present invention; Figure 3 is a curve diagram of hydrogen peroxide production under different oxygen aeration amounts of the present invention; Figure 4 is a curve diagram of hydrogen peroxide production at different pH values ​​of the present invention; Figure 5 It is a curve diagram of hydrogen peroxide production under different current intensities of the present invention.

[0020] Reference numerals: 1. Conductive wire; 2. Conductive material carbon felt; 3. Membrane shell base; 4. Membrane shell air inlet cover; 5. Hollow polyvinylidene fluoride fiber hydrophobic membrane; 6. Curtain aeration electrode; 7. Ti / IrO2 / RuO2 anode; 8. Oxygen tank; 9. Oxygen pressure gauge; 10. Gas flow meter; 11. Oxygen supply pipeline; 12. Ampereometer and voltmeter; 13. Stirring unit; 14. Magnetic rotor; 15. Electrolytic cell. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Unless otherwise defined, the technical terms or scientific terms used in the present invention should be the common meanings understood by people with ordinary skills in the field to which the present invention belongs. The above-mentioned features or features mentioned in the specific examples mentioned in the present invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0022] Example 1 like Figure 1 As shown, the present invention provides a method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide, comprising the following steps: S1. Mix ethanol and water in a volume ratio of 1:1 to obtain a pretreatment solution, cut the conductive material carbon felt 2 into the same length and put it into the pretreatment solution for ultrasonic cleaning for 20 minutes, then put it into deionized water for ultrasonic cleaning for 30 minutes, and dry it at 80°C for 2 hours to obtain the pretreated conductive material carbon felt 2.

[0023] S2. Insert the conductive wire 1 into the pre-treated conductive material carbon felt 2 obtained in S1 to obtain a supporting conductive material.

[0024] S3, winding and fixing the supporting conductive material in S2 on the outside of the hollow polyvinylidene fluoride fiber hydrophobic membrane 5, with the winding line density being 1-2 g / m, to obtain an aeration electrode strip.

[0025] The aeration electrode strips in this embodiment use the hollow polyvinylidene fluoride fiber hydrophobic membrane 5 to transmit oxygen. The hollow polyvinylidene fluoride fiber hydrophobic membrane 5 is hydrophobic and can prevent substances such as electrolytes in the water phase from entering the membrane, while allowing reactants such as gaseous oxygen to diffuse through the membrane pores to the surface of the supporting conductive material. The carbon felt 2 in the supporting conductive material can promote the adsorption and activation of oxygen on the surface of the aeration electrode strips, provide active sites for the reduction reaction of oxygen, catalyze the two-electron reduction reaction of oxygen to generate hydrogen peroxide under the action of the electric field, and help improve the generation efficiency and selectivity of hydrogen peroxide.

[0026] S4. Connect several aeration electrode strips obtained in S3 to the membrane shell assembly in sequence. The membrane shell assembly includes a membrane shell base 3 and a membrane shell air inlet top cover 4. The membrane shell base 3 and the membrane shell air inlet top cover 4 are connected through a hollow polyvinylidene fluoride fiber hydrophobic membrane 5. The hollow polyvinylidene fluoride fiber hydrophobic membrane 5 is connected to the membrane shell air inlet top cover 4 to obtain a curtain aeration electrode 6.

[0027] Example 2 like Figure 2 As shown, the curtain aeration electrode in Example 1 is used in a high-efficiency hydrogen peroxide production system. The high-efficiency hydrogen peroxide production system includes an electrolysis unit, an oxygen supply unit and a stirring unit 13. The curtain aeration electrode 6 of the electrolysis unit is connected to the oxygen tank 8 of the oxygen supply unit, and the magnetic rotor 14 of the stirring unit 13 is located in the electrolysis cell 15 of the electrolysis unit.

[0028] The curtain aeration electrode 6 can promote the efficient electroreduction of dissolved oxygen to generate H2O2 at low energy consumption, wherein oxygen enters the hollow polyvinylidene fluoride fiber hydrophobic membrane 5 and then aerates into the electrolyte. The submicron bubbles generated during the aeration process have a large specific surface area. Since the conductive material carbon felt 2 has a three-dimensional pore structure and good conductivity, the submicron bubbles are exposed to the surface of the curtain aeration electrode 6 and obtain electrons under the action of a DC electric field, which greatly shortens the distance of oxygen mass transfer, so that O2 can efficiently generate H2O2 at a low aeration volume, effectively reducing the overall energy consumption.

[0029] An anode assembly is provided in the electrolytic cell 15 of the electrolytic unit. The anode assembly is a titanium-based coated electrode Ti / IrO2 / RuO2 anode 7. The curtain aeration electrode 6 and the anode assembly are electrically connected to the current and voltage meter 12 respectively.

[0030] The oxygen tank 8 of the oxygen supply unit is connected to the aeration electrode through an oxygen supply pipeline 11 . A gas flow meter 10 is provided on the oxygen supply pipeline 11 , and an oxygen pressure gauge 9 is provided on the oxygen tank 8 .

[0031] Test Example 1 a. Different oxygen aeration amounts Using the high-efficiency hydrogen peroxide production system in Example 2, the production of hydrogen peroxide was tested in a 0.05M anhydrous sodium sulfate electrolyte with a current intensity of 0.05A and a pH of 3 at different oxygen aeration rates, with the oxygen aeration rates being 5 ml / min, 10 ml / min, 15 ml / min and 20 ml / min, respectively. The results are shown in FIG. Figure 3 As shown, it can be seen that when the oxygen aeration rate is 10ml / min, the H2O2 production is the highest.

[0032] b. Different electrolyte pH The system for efficiently producing hydrogen peroxide in Example 2 was used to control the current intensity to 0.05A and the oxygen aeration volume to 10ml / min. The production of hydrogen peroxide at different pH values ​​was tested in 0.05M anhydrous sodium sulfate electrolyte. The pH values ​​were 3, 5, 7 and 9, respectively. The results are shown in FIG. Figure 4 As shown, it can be seen that when the pH is 3, the production of H2O2 is the highest.

[0033] c. Different current strength Using the high-efficiency hydrogen peroxide production system in Example 2, the production of hydrogen peroxide at different current intensities was tested in a 0.05M anhydrous sodium sulfate electrolyte with an oxygen aeration rate of 10 ml / min and a pH of 3. The current intensities were 0.01A, 0.02A, 0.03A, 0.04A, 0.05A and 0.06A, respectively. The results are shown in FIG. Figure 5As shown in the figure, when the current intensity increases from 0.05A to 0.06A, the increase in H2O2 production is not large. Considering the comprehensive energy consumption, the optimal current intensity is 0.05A, and the H2O2 production is 140mg / L.

[0034] Therefore, the present invention adopts the above-mentioned preparation method and application of the curtain aeration electrode for efficiently producing hydrogen peroxide. The curtain aeration electrode is obtained by winding a hollow hydrophobic membrane material with carbon felt. It can efficiently utilize oxygen to efficiently produce H2O2 under low energy consumption, has good mass transfer effect, high oxygen utilization rate, high current efficiency, and is safe and easy to operate.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide, characterized in that: The following steps are included: S1, cutting the conductive material into the same length and placing it in a pretreatment solution for ultrasonic cleaning, then placing it in deionized water for ultrasonic cleaning, and drying to obtain a pretreated conductive material; S2, inserting a supporting material into the pretreated conductive material obtained in S1 to obtain a supporting conductive material; S3, winding and fixing the supporting conductive material in S2 on the outside of the hydrophobic membrane material to obtain an aeration electrode strip; S4. Connecting several aeration electrode strips obtained in S3 to the membrane shell assembly in sequence to obtain a curtain aeration electrode.

2. The method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 1, characterized in that: In S1, the pretreatment solution is ethanol and water mixed in a volume ratio of 1-3:1, the drying temperature is 60-100°C, and the drying time is 0.5-3h.

3. The method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 1, characterized in that: In S2, the supporting material is a conductive wire, and the conductive wire includes one or more of a titanium wire and a nickel wire.

4. The method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 1, characterized in that: In S3, the hydrophobic membrane material is a hollow hydrophobic membrane material, and the winding line density of the supporting conductive material is 1-2 g / m.

5. The method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 4, characterized in that: The hollow hydrophobic membrane material includes one or more of a hollow polytetrafluoroethylene fiber hydrophobic membrane, a hollow polyvinylidene fluoride fiber hydrophobic membrane, and a hollow polypropylene fiber hydrophobic membrane.

6. The method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 1, characterized in that: In S4, the membrane shell assembly includes a membrane shell base and a membrane shell air inlet top cover, the membrane shell base and the membrane shell air inlet top cover are connected by a hydrophobic membrane material, and the hydrophobic membrane material is in communication with the membrane shell air inlet top cover.

7. Use of the curtain aeration electrode prepared by the method for preparing a curtain aeration electrode for efficiently producing hydrogen peroxide according to any one of claims 1 to 6 in a system for efficiently producing hydrogen peroxide.

8. The use of a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 7, characterized in that: The high-efficiency hydrogen peroxide production system comprises an electrolysis unit, an oxygen supply unit and a stirring unit. The curtain aeration electrode of the electrolysis unit is connected to the oxygen tank of the oxygen supply unit, and the magnetic rotor of the stirring unit is located in the electrolysis cell of the electrolysis unit.

9. The use of a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 8, characterized in that: An anode assembly is arranged in the electrolytic cell of the electrolytic unit, and the curtain aeration electrode and the anode assembly are electrically connected to the current and voltage meters respectively.

10. The use of a curtain aeration electrode for efficiently producing hydrogen peroxide according to claim 8, characterized in that: The oxygen tank of the oxygen supply unit is connected with the aeration electrode through an oxygen supply pipeline. A gas flow meter is arranged on the oxygen supply pipeline, and an oxygen pressure gauge is arranged on the oxygen tank.

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