HYDROGEN PEROXIDE PRODUCTION DEVICE AND USE THEREOF

Abstract

A gas diffusion electrode includes a carbon fiber tube, a support layer, and a catalyst layer. The carbon fiber tube is straight and functions as a substrate. The support layer includes a carbon black-polytetrafluoroethylene (PTFE) coating, and is disposed on the substrate. The catalyst layer includes carbon black, anhydrous ethanol, and PTFE, and is disposed on the support layer. The gas diffusion electrode has a diameter of 3-20 mm and a length of 50-500 mm.

Claims

1. A gas diffusion electrode, comprising a carbon fiber tube, a support layer, and a catalyst layer; wherein the carbon fiber tube is straight and functions as a substrate; the support layer comprises a carbon black-polytetrafluoroethylene (PTFE) coating, and is disposed on the substrate; the catalyst layer comprises carbon black, anhydrous ethanol, and PTFE, and is disposed on the support layer; and the gas diffusion electrode has a diameter of 3-20 mm and a length of 50-500 mm.

2. A hydrogen peroxide production device, comprising a plurality of hydrogen peroxide production units connected to each other; wherein each hydrogen peroxide production unit comprises a cathode, an insulating sleeve, and an anode from inside to outside; and the cathode is the gas diffusion electrode of claim 1.

3. The device of claim 2, wherein the anode is a titanium substrate comprising an iridium dioxide coating.

4. The device of claim 3, wherein a distance between the anode and the cathode is 1-30 mm.

5. The device of claim 4, wherein the insulating sleeve has a thickness of 1-30 mm, and comprises an organic silica, an organic plastic, or an inorganic ceramic material.

6. The device of claim 2, further comprising a power supply, an electro-Fenton reactor, an air compressor, a water pump, a tank, an air pipe, and a conduit; wherein the plurality of hydrogen peroxide production units are connected to each other and disposed in the electro-Fenton reactor; the electro-Fenton reactor comprises a top part and a bottom part; a water inlet is disposed on the bottom part and an overflow outlet is disposed on the top part; one end of the air pipe is connected to the electro-Fenton reactor; another end of the air pipe is connected to the air compressor; one end of the water pump is connected to the water inlet; another end of the water pump is connected to the tank; and the tank is connected to the overflow outlet through the conduit.

7. A method of preparing hydrogen peroxide using the hydrogen peroxide production device of claim 6, the method comprising: turning on the air compressor to aerate the electro-Fenton reactor; turning on the water pump to pump a sodium sulfate solution into the electro-Fenton reactor until the sodium sulfate solution covers the plurality of hydrogen peroxide production units; controlling the current of the hydrogen peroxide production device, so that a solid, liquid and gas three-phase interface is formed on the catalyst layer of the gas diffusion electrode, to produce hydrogen peroxide.

8. The method of claim 7, wherein the hydrogen peroxide production device is operated at a current density of 10-200 mA/cm.sup.2 and a voltage of 2.0-4.0 V; and the air compressor offers an air flow rate of 10-150 L/min.

9. The method of claim 8, wherein a concentration of the sodium sulfate solution is 0.05-0.15 M.

10. A method for wastewater treatment using the hydrogen peroxide production device of claim 6, the method comprising: 1) turning on the air compressor to aerate the electro-Fenton reactor; preparing a wastewater sample containing an organic pollutant, sodium sulfate anhydrous, and Fe.sup.2+; turning on the water pump to pump the wastewater sample into the electro-Fenton reactor until the wastewater sample covers the plurality of hydrogen peroxide production units; controlling the current of the hydrogen peroxide production device, so that a solid, liquid and gas three-phase interface is formed on the catalyst layer of the gas diffusion electrode, to produce hydrogen peroxide; 2) generating hydroxyl radicals from hydrogen peroxide to mineralize the organic pollutant; and discharging an effluent into the tank via the overflow outlet; and 3) recycling the effluent produced in 2) to the electro-Fenton reactor through a circulation process.

11. The method of claim 10, wherein in 1), the hydrogen peroxide production device is operated at a current density of 10-200 mA/cm.sup.2 and a voltage of 2.0-4.0 V; and the air compressor offers an air flow rate of 10-150 L/min.

Description

DETAILED DESCRIPTION OF THE DRAWINGS

[0040] FIG. 1A is a front view of a hydrogen peroxide production unit according to one example of the disclosure; FIG. 1B is a sectional view taken from line A-A in FIG. 1A;

[0041] FIG. 2 is a perspective view of a plurality of hydrogen peroxide production units used in conjunction with a cuboid electron-Fenton reactor according to one example of the disclosure;

[0042] FIG. 3 is a perspective view of a hydrogen peroxide production device according to one example of the disclosure;

[0043] FIG. 4 is a graph showing a production volume of hydrogen peroxide versus time for different amounts of a catalyst;

[0044] FIG. 5 is a graph showing current efficiency versus time for different amounts of catalyst;

[0045] FIG. 6 is a graph showing a production volume of hydrogen peroxide versus time for different current densities; and

[0046] FIG. 7 is a graph showing the concentration of Ibuprofen versus time for different concentrations of Fe.sup.2+.

[0047] In the drawings, the following reference numbers are used: 1. Power supply; 2. Cathode lead; 3. Anode lead; 4. Overflow outlet; 5. Tank; 6. Inlet pipe; 7. Water pump; 8. Water inlet; 9. Air pipe; 10. Air compressor; 11. Anode; 12. Cathode; and 13. Insulating sleeve.

DETAILED DESCRIPTION

[0048] Unspecified reaction conditions follow conventional conditions or manufacturer's recommendations. Reagents or instruments that do not specify the manufacturer or preparation method are conventional products that can be purchased from the market.

[0049] As used herein, the term “approximately,” as applied to one or more values of interest, refers to a value that is similar to a stated reference value. Throughout this application, various examples of this disclosure may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention.

[0050] The term “at least one” as used herein refers to one or more. For example, the term “at least one of A, B, and C” refers to A, B, C, or a combination thereof.

[0051] Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 3 should be considered to have specifically disclosed subranges such as from 1 to 3, from 2 to 4 etc., as well as individual numbers within that range, for example, 2 3, and 4. The same principle applies to ranges defined by only one numerical value, such as “less than or equal to about 4.5.

[0052] It is to be understood that such corresponding descriptions are not limited by the order of the steps, as some steps may occur in different orders and/or concurrently with other steps from what is depicted and described herein.

Example 1

[0053] The example provides a gas diffusion electrode and a preparation method thereof.

[0054] As shown in FIG. 1, the gas diffusion electrode was in the shape of a tube having a diameter of 8 mm and a length of 500 mm. The gas diffusion electrode comprised a carbon fiber tube, a support layer, and a catalyst layer; the carbon fiber tube was used as a substrate; the support layer comprised a coating comprising carbon black and PTFE, and was formed on the carbon fiber tube; the catalyst layer comprised carbon black, anhydrous ethanol, and PTFE, and was disposed on the support layer; the coating was used to reduce static electricity and used as a catalyst to promote two-electron oxygen reduction, while maintaining conductivity; as a result, the catalyst was attached on the surface of the gas diffusion electrode; and the shape of the carbon fiber tube allowed easy connection and improved oxygen mass transfer efficiency.

[0055] The preparation method of the gas diffusion electrode is detailed as follows:

[0056] S1. 100-400 carbon fiber filaments were woven into a strand of carbon fiber; 20-30 strands of carbon fiber were woven into a carbon fiber tube; the carbon fiber tube was ultrasonically vibrated in an acetone solution and washed with ultrapure water;

[0057] S2. carbon black and a polytetrafluoroethylene (PTFE) solution were mixed at a weight ratio of between 1:40 and 10:40 to form a first mixture; and a coating of the first mixture was formed on the surface of the carbon fiber tube; the coating was used to reduce static electricity and used as a catalyst to promote two-electron oxygen reduction, while maintaining conductivity; as a result, the catalyst was attached on the carbon fiber tube;

[0058] S3. the carbon fiber tube was placed in a muffle furnace at 300-400° C. for 20-40 min; and S3 was repeated 2-3 times; and

[0059] S4. carbon black, anhydrous ethanol, and PTFE were mixed to form a second mixture; a layer of the second mixture as a catalyst layer was formed on the surface of the carbon fiber tube obtained in S3; and the carbon fiber tube was placed in the muffle furnace at 300-400° C. for 20-40 min.

Example 2

[0060] The example provides a hydrogen peroxide production unit.

[0061] As shown in FIG. 1, the hydrogen peroxide production unit comprised an anode 11, a cathode 12, and an insulating sleeve 13; the anode comprised a titanium substrate comprising a metal oxide coating; the cathode 12 was the gas diffusion electrode in Example 1; and the insulating sleeve 13 had a thickness of 10 mm and was disposed between the anode 11 and the cathode 12. The anode 11 and cathode 12 were coaxially connected to the insulating sleeve 13 thus improving the oxygen mass transfer efficiency.

Example 3

[0062] The example provides a hydrogen peroxide production device and a use thereof.

[0063] As shown in FIG. 3, the hydrogen peroxide production device comprised an electro-Fenton reactor, a power supply 1, a cathode lead 2, an anode lead 3, an overflow outlet 4, a tank 5, a water inlet pipe 6, a water pump 7, a water inlet 8, an air pipe 9, and an air compressor 10; the water inlet pipe 6 was disposed between the tank 5 and the water pump 7; one end of the air pipe 9 was connected to the electro-Fenton reactor; another end of the air pipe 9 was connected to the air compressor 10; one end of the water pump 7 was connected to the water inlet 8; another end of the water pump 7 was connected to the tank 5; and the tank 5 was connected to the overflow outlet 4 through a conduit. As shown in FIG. 2, the electro-Fenton reactor comprised a cuboid structure comprising eight hydrogen peroxide production units prepared in Example 2.

[0064] In use, 0.05-0.15 M sodium sulfate solution was added to the tank 5; the water pump 7 was turned on and pumped the sodium sulfate solution from the tank 5 to the electro-Fenton reactor through the water inlet 8, until the eight hydrogen peroxide production units were submerged in the sodium sulfate solution; the air compressor 10 was turned on and aerated the electro-Fenton reactor at an air flow rate of 10-150 L/min; a current density was 10-200 mA/cm.sup.2 and a voltage was 2.0-4.0 V; as a result, the water formed a solid, liquid and gas three-phase interface on the gas diffusion electrode, to produce hydrogen peroxide; an effluent produced in the electro-Fenton reactor flowed into the tank 5 through the overflow outlet 4 and was treated by a circulating process.

Example 4

[0065] In the example, the hydrogen peroxide production device was operated at different amounts of catalyst. The hydrogen peroxide production device was as shown in FIG. 3 and operated under the conditions: 0.05 M sodium sulfate solution (Na.sub.2SO.sub.4), pH=7, a current density of 10 mA/cm.sup.2, and an air flow rate of 32 L/min.

[0066] S1. 0.2 L of sodium sulfate solution was added to the tank; and the water pump was turned on; and

[0067] S2. the eight hydrogen peroxide production units were submerged in the sodium sulfate solution; the air compressor and the power supply were turned on; and a constant current density was 10 mA/cm.sup.2. In use, a distance between the anode and cathode in the electro-Fenton reactor was 10 mm; the oxygen in the air entered the electro-Fenton reactor through the air pump; and a solid, liquid and gas three-phase interface was formed on the surface of the gas diffusion cathode to increase oxygen mass transfer efficiency; the oxygen undergone two-electron oxygen reduction in the present of catalyst to form hydrogen peroxide. After repeated producing hydrogen peroxide, the solution in the tank is sampled for measurement of the concentration of hydrogen peroxide.

[0068] FIG. 4 is a graph showing a production volume of hydrogen peroxide versus time for different amounts of catalyst. FIG. 5 is a graph showing current efficiency versus time for different amounts of catalyst. The hydrogen peroxide volume reached 450 mg/L after the reaction proceeded for 3 hours.

Example 5

[0069] In the example, hydrogen peroxide production device was operated at different current densities. The hydrogen peroxide production device is shown in FIG. 3 and run under the conditions: 0.05 M Na.sub.2SO.sub.4, pH=7, a current density of 10-30 mA/cm.sup.2, and an air flow rate of 32 L/min.

[0070] S1. 0.2 L of sodium sulfate solution was added to the tank; and the water pump was turned on; and

[0071] S2. the eight hydrogen peroxide production units were submerged in the sodium sulfate solution; the air compressor and the power supply were turned on; and a constant current density was 10, 15, 20, and 30 mA/cm.sup.2. In use, a distance between the anode and cathode in the electro-Fenton reactor was 10 mm; the oxygen in the air entered the electro-Fenton reactor through the air pump; and a solid, liquid and gas three-phase interface was formed on the surface of the gas diffusion cathode to increase oxygen mass transfer efficiency; the oxygen undergone two-electron oxygen reduction in the present of catalyst to form hydrogen peroxide. After repeated producing hydrogen peroxide, the solution in the tank was sampled for determination of the concentration of hydrogen peroxide. The hydrogen peroxide volume reached 1000 mg/L after the reaction proceeded for 3 hours. The hydrogen peroxide production device was switched to a continuous flow mode that lasts for three hours. FIG. 6 is a graph showing a production volume of hydrogen peroxide versus time for different current densities.

Example 6

[0072] In the example, ibuprofen (IBP)-containing wastewater was treated by the hydrogen peroxide production device as shown in FIG. 3. The hydrogen peroxide production device was operated under the conditions: 10 mg/L IBP; 0.05 M Na.sub.2SO.sub.4; 0.3-1.0 M Fe.sup.2+; a current density of 10 mA/cm.sup.2; and an air flow rate of 32 L/min.

[0073] S1. The IBP-containing wastewater was prepared and added to the tank; the water pump and the air compressor was turned on;

[0074] S2. when the IBP-containing wastewater became turbulent, the power supply was turned on; and the hydrogen peroxide production device was operated at a constant current density of 10 mA/cm.sup.2; and

[0075] S3. the solution in the tank was sampled at regular intervals for determination of the concentration of IBP.

[0076] FIG. 7 is a graph showing concentration of ibuprofen versus time for different concentrations of Fe.sup.2+. The results show that a degradation efficiency of ibuprofen was 99.13%.

[0077] It will be obvious to those skilled in the art that changes and modifications may be made, and therefore, the aim in the appended claims is to cover all such changes and modifications.