Preparation method and application of curtain type aeration electrode for high-efficiency hydrogen peroxide production

Abstract

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

Description

TECHNICAL FIELD

[0001] The application relates to the field of electrochemistry, in particular to a preparation method and application of a curtain type aeration electrode for efficiently generating hydrogen peroxide. BACKGROUND

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

[0003] On the other hand, the concentration of dissolved oxygen in the solution can be increased to strengthen the cathode electro-synthesis H2O2, which is a safe and efficient method. Some researchers have designed a pressurized jet aerator based on the Venturi effect, which has improved the oxygen concentration of the system to a certain extent. However, to achieve efficient electro-generation of H2O2, the pressure of the backflow liquid needs to be increased, 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 micro-bubbles through the membrane holes, effectively improving the concentration of dissolved oxygen in the solution. However, the H2O2 generation efficiency is limited by the mass transfer distance, and part of the oxygen cannot reach the electrode surface to undergo oxygen reduction reaction. In addition, the high aeration amount also hinders its further popularization and application. SUMMARY

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

[0005] To achieve the above purpose, the present application provides a preparation method of a curtain type aeration electrode for efficiently generating hydrogen peroxide, comprising the following steps,

[0006] S1, cut the conductive material into the same length, then put it into a pretreatment solution for ultrasonic cleaning, then put it into deionized water for ultrasonic cleaning, and then dry to obtain a pretreated conductive material;

[0007] S2, insert the support material into the cut conductive material obtained in S1, to obtain a support conductive material;

[0008] S3, wrap and fix the support conductive material in S2 outside the hydrophobic membrane material, to obtain an aeration electrode strip;

[0009] S4, connect a plurality of aeration electrode strips obtained in S3 with the membrane shell assembly in sequence, to obtain a curtain type aeration electrode.

[0010] Preferably, the conductive material comprises one or more of carbon felt and plastic conductive material.

[0011] Preferably, in S1, the pretreatment solution is a mixture of ethanol and water in a volume ratio of 1-3:1, the drying temperature is 60-100 DEG C, and the drying time is 0.5-3h.

[0012] Preferably, in S2, the support material is a conductive wire, and the conductive wire comprises one or more of titanium wire and nickel wire.

[0013] Preferably, in S3, the hydrophobic membrane material is a hollow hydrophobic membrane material, and the winding line density of the support conductive material is 1-2g / m.

[0014] The hollow hydrophobic membrane material is used for aeration, microbubble aeration is carried out under low aeration amount by using the surface micropore, and submicron bubbles generated have a large specific surface area, so that sufficient O2 can be provided for oxygen reduction reaction under low aeration amount, and the overall energy consumption is effectively reduced.

[0015] Preferably, the hollow hydrophobic membrane material comprises one or more of hollow polytetrafluoroethylene fiber hydrophobic membrane, hollow polyvinylidene fluoride fiber hydrophobic membrane and hollow polypropylene fiber hydrophobic membrane.

[0016] Preferably, in S4, the membrane shell assembly comprises a membrane shell base and a membrane shell gas inlet top cover, the membrane shell base and the membrane shell gas inlet top cover are connected through the hydrophobic membrane material, and the hydrophobic membrane material is in communication with the membrane shell gas inlet top cover.

[0017] The curtain type aeration electrode prepared by the above-mentioned method for preparing a curtain type aeration electrode for efficiently producing hydrogen peroxide is applied in a high-efficiency hydrogen peroxide production system.

[0018] Preferably, the high-efficiency hydrogen peroxide production system comprises an electrolysis unit, an oxygen supply unit and a stirring unit, the curtain type aeration electrode of the electrolysis unit is in communication with an oxygen tank of the oxygen supply unit, and a magnetic rotor of the stirring unit is located in an electrolytic cell of the electrolysis unit.

[0019] Preferably, the electrolytic cell of the electrolysis unit is provided with an anode assembly, and the curtain type aeration electrode and the anode assembly are respectively electrically connected with a current-voltage meter.

[0020] Preferably, the oxygen tank of the oxygen supply unit is communicated 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.

[0021] Therefore, the application has the beneficial effects that:

[0022] 1. The preparation method is simple to operate, does not need expensive modified electrodes and complex reaction units, reduces production cost, the hollow fiber hydrophobic membrane used has high porosity and large specific surface area, the aeration effect is good and energy-efficient, and the hollow fiber hydrophobic membrane exhibits excellent performance in strengthening the transfer rate of gas molecules at the gas-liquid interface.

[0023] 2. The curtain-type aeration electrode obtained by winding the hollow hydrophobic membrane material with carbon felt can efficiently utilize oxygen to produce H2O2 at low energy consumption, has good mass transfer effect, high oxygen utilization rate and high current efficiency, and is safe and easy to operate.

[0024] 3. The curtain-type aeration electrode avoids the disadvantages of additional addition of H2O2 in the existing electro-Fenton process, and reduces the safety hazards in transportation and storage.

[0025] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of a curtain-type aeration electrode for efficiently producing hydrogen peroxide according to the application;

[0027] Figure 2 is a schematic diagram of a hydrogen peroxide production system according to the application;

[0028] Figure 3 is a curve diagram of hydrogen peroxide production under different oxygen aeration amounts according to the application;

[0029] Figure 4 is a curve diagram of hydrogen peroxide production under different pH values according to the application;

[0030] Figure 5 is a curve diagram of hydrogen peroxide production under different current intensities according to the application.

[0031] Reference signs:

[0032] 1. Conductive wire; 2. Conductive carbon felt; 3. Membrane housing base; 4. Membrane housing air inlet top cover; 5. Hollow polyvinylidene fluoride fiber hydrophobic membrane; 6. Curtain-type aeration electrode; 7. Ti / IrO2 / RuO2 anode; 8. Oxygen tank; 9. Oxygen pressure gauge; 10. Gas flow meter; 11. Oxygen supply pipeline; 12. Ammeter and voltmeter; 13. Stirring unit; 14. Magnetic rotor; 15. Electrolytic cell. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0034] Example 1

[0035] like Figure 1 As shown, this invention provides a method for preparing a curtain-type aeration electrode for high-efficiency hydrogen peroxide production, comprising the following steps:

[0036] S1. Mix ethanol and water in a volume ratio of 1:1 to obtain a pretreatment solution. Cut the conductive carbon felt 2 into the same length and place it in the pretreatment solution for ultrasonic cleaning for 20 min. Then place it in deionized water for ultrasonic cleaning for 30 min and dry it at 80℃ for 2 h to obtain the pretreated conductive carbon felt 2.

[0037] S2. Insert conductive wire 1 into the pretreated conductive material carbon felt 2 obtained in S1 to obtain a supporting conductive material.

[0038] S3. The supporting conductive material in S2 is wound and fixed around the hollow polyvinylidene fluoride fiber hydrophobic membrane 5, with a winding linear density of 1-2 g / m, to obtain the aeration electrode strip.

[0039] In this embodiment, the aeration electrode strip uses a hollow polyvinylidene fluoride fiber hydrophobic membrane 5 to transport oxygen. The hollow polyvinylidene fluoride fiber hydrophobic membrane 5 is hydrophobic, preventing electrolytes and other substances in the aqueous phase from entering the membrane, while allowing gaseous oxygen and other reactants 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 strip, providing active sites for the oxygen reduction reaction. Under the action of an electric field, it catalyzes the two-electron reduction reaction of oxygen to generate hydrogen peroxide, helping to improve the generation efficiency and selectivity of hydrogen peroxide.

[0040] S4, connect the aeration electrode strips obtained in S3 to the membrane shell assembly in sequence, the membrane shell assembly comprising a membrane shell base 3 and a membrane shell gas inlet top cover 4, the membrane shell base 3 and the membrane shell gas inlet top cover 4 being connected by a hollow polyvinylidene fluoride fiber hydrophobic membrane 5, the hollow polyvinylidene fluoride fiber hydrophobic membrane 5 being in communication with the membrane shell gas inlet top cover 4, to obtain a curtain type aeration electrode 6.

[0041] Example 2

[0042] As shown in Figure 2 , the application of the curtain type aeration electrode in Example 1 in a high-efficiency hydrogen peroxide production system, the high-efficiency hydrogen peroxide production system comprising an electrolysis unit, an oxygen supply unit and a stirring unit 13, the curtain type aeration electrode 6 of the electrolysis unit being in communication with the oxygen tank 8 of the oxygen supply unit, the magnetic rotor 14 of the stirring unit 13 being located in the electrolytic cell 15 of the electrolysis unit.

[0043] The curtain type aeration electrode 6 can promote the efficient electro-reduction of dissolved oxygen to generate H2O2 at low energy consumption, wherein the oxygen enters the hollow polyvinylidene fluoride fiber hydrophobic membrane 5 and is aerated into the electrolyte, the sub-micron bubbles generated during the aeration process have a large specific surface area, and since the conductive material carbon felt 2 has a three-dimensional pore structure and good electrical conductivity, the sub-micron bubbles exposed to the surface of the curtain type aeration electrode 6 can obtain electrons under the action of a direct current electric field, greatly shortening the oxygen mass transfer distance, so that O2 can be efficiently generated into H2O2 at low aeration rate, effectively reducing the overall energy consumption.

[0044] The electrolytic cell 15 of the electrolysis unit is provided with an anode assembly, which is a titanium-based coated electrode Ti / IrO2 / RuO2 anode 7, and the curtain type aeration electrode 6 and the anode assembly are respectively electrically connected with the current-voltage meter 12.

[0045] The oxygen tank 8 of the oxygen supply unit is in communication with the aeration electrode through the oxygen supply pipeline 11, and the oxygen supply pipeline 11 is provided with a gas flow meter 10, and the oxygen tank 8 is provided with an oxygen pressure gauge 9.

[0046] Test Example 1

[0047] a, different oxygen aeration rates

[0048] Using the high-efficiency hydrogen peroxide production system in Example 2, the hydrogen peroxide production under different oxygen aeration rates was tested in a 0.05M anhydrous sodium sulfate electrolyte with a current intensity of 0.05A and a pH of 3, and the oxygen aeration rates were 5ml / min, 10ml / min, 15ml / min and 20ml / min in sequence. As shown in Figure 3 , it can be seen that when the oxygen aeration rate is 10ml / min, the production of H2O2 is the highest.

[0049] b, different electrolyte pH

[0050] Using the system for efficiently producing hydrogen peroxide in Example 2, the production of hydrogen peroxide at different pHs was tested in 0.05M anhydrous sodium sulfate electrolyte with a current intensity of 0.05A and an oxygen aeration amount of 10ml / min, and the pHs were 3, 5, 7 and 9 in turn. The results are shown in Table 1. Figure 4 As can be seen from Table 1, when the pH is 3, the production of H2O2 is the highest.

[0051] c. Different current intensities

[0052] Using the system for efficiently producing hydrogen peroxide in Example 2, the production of hydrogen peroxide at different current intensities was tested in 0.05M anhydrous sodium sulfate electrolyte with a pH of 3 and an oxygen aeration amount of 10ml / min, and the current intensities were 0.01A, 0.02A, 0.03A, 0.04A, 0.05A and 0.06A in turn. The results are shown in Table 2. Figure 5 As can be seen from Table 2, when the current intensity is increased from 0.05A to 0.06A, the production of H2O2 does not increase much, and considering the overall energy consumption, the optimal current intensity is 0.05A, and the production of H2O2 is 140mg / L.

[0053] Therefore, the application adopts the above-mentioned preparation method and application of the curtain-type aeration electrode for efficiently producing hydrogen peroxide. The curtain-type aeration electrode is obtained by winding a carbon felt around a hollow hydrophobic membrane material, and can efficiently produce H2O2 at low energy consumption by efficiently utilizing oxygen. The mass transfer effect is good, the oxygen utilization rate is high, and the current efficiency is high, and the operation is safe and easy.

[0054] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for preparing a curtain-type aeration electrode for high-efficiency hydrogen peroxide production, characterized in that: Includes the following steps, S1. After cutting the conductive material into the same length, place it in the pretreatment solution for ultrasonic cleaning, then place it in deionized water for ultrasonic cleaning, and dry it to obtain the pretreated conductive material. In S1, the conductive material is carbon felt; S2. Insert a support material into the pretreated conductive material obtained in S1 to obtain a support conductive material; In S2, the supporting material is a conductive wire, which includes one or more of titanium wire and nickel wire; S3. Wrap and fix the supporting conductive material from S2 around the hydrophobic membrane material to obtain the aeration electrode strip; In S3, the hydrophobic membrane material is a hollow hydrophobic membrane material; S4. Connect several aeration electrode strips obtained in S3 to the membrane housing assembly in sequence to obtain a curtain-type aeration electrode.

2. The method for preparing a curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 1, characterized in that: In S1, the pretreatment solution is a mixture of ethanol and water in a volume ratio of 1-3:1, the drying temperature is 60-100℃, and the drying time is 0.5-3h.

3. The method for preparing a curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 1, characterized in that: In S3, the winding linear density of the supporting conductive material is 1-2 g / m.

4. The method for preparing a curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 1, characterized in that: Hollow hydrophobic membrane materials include one or more of hollow polytetrafluoroethylene fiber hydrophobic membranes, hollow polyvinylidene fluoride fiber hydrophobic membranes, and hollow polypropylene fiber hydrophobic membranes.

5. The method for preparing a curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 1, characterized in that: In S4, the membrane housing assembly includes a membrane housing base and a membrane housing inlet top cover. The membrane housing base and the membrane housing inlet top cover are connected by a hydrophobic membrane material, and the hydrophobic membrane material is in communication with the membrane housing inlet top cover.

6. An application of a curtain-type aeration electrode for high-efficiency hydrogen peroxide production, characterized in that: The curtain aeration electrode prepared by the method for preparing a high-efficiency hydrogen peroxide production curtain aeration electrode according to any one of claims 1-5 is applied in a high-efficiency hydrogen peroxide production system.

7. The application of the curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 6, characterized in that: The high-efficiency hydrogen peroxide production system includes an electrolysis unit, an oxygen supply unit, and a stirring unit. The curtain-type 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.

8. The application of the curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 7, characterized in that: The electrolysis unit is equipped with an anode assembly in the electrolysis cell. The curtain-type aeration electrode and the anode assembly are electrically connected to an ammeter and a voltmeter, respectively.

9. The application of the curtain-type aeration electrode for high-efficiency hydrogen peroxide production according to claim 7, characterized in that: The oxygen tank of the oxygen supply unit is connected to the aeration electrode through an oxygen supply pipeline. The oxygen supply pipeline is equipped with a gas flow meter, and the oxygen tank is equipped with an oxygen pressure gauge.

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