Establishment method and application of electrochemical deoxidization system

Abstract

The invention discloses an establishment method and application of an electrochemical deoxidization system. The specific method comprises the following steps: dissolving silicotungstic acid in a dilute phosphoric acid solution as a catholyte, using a phosphoric acid solution with the same concentration as an anolyte, and carrying out electrochemical reaction in a flowing electrolytic cell; the reaction method provided by the invention is simple in process, low in cost and good and stable in oxygen removal performance. In a closed container of 50 mL, by taking a reversible hydrogen electrode as a standard and under-1.75 volts, the oxygen content can be reduced to 5% or below within 42 minutes, and the oxygen removal capacity is not reduced after multiple cycles within 1000 minutes; when the volume of the container is changed into a large-volume container of 500mL and a large-volume container of 3.5 L, the system can reduce the oxygen content to below 5% after 4 hours and 26 hours respectively.

Description

Technical Field

[0001] The invention belongs to the field of electrochemistry, and in particular relates to the establishment of an electrochemical deoxygenation system. Background Art

[0002] In the process of industrial boilers, oil field production, medical research, electronic device production and daily life, the presence of oxygen often causes a series of problems such as equipment corrosion, well blockage, product quality degradation, and food and drug quality degradation. In industry, the corrosion rate of carbon steel pipelines in oxygenated water environment can reach 0.12mm / year. Its mechanism of action is Fe→Fe 2+ +2e - The anodic oxidation reaction not only shortens the life of the equipment, but also causes an increase of more than $2 billion in global industrial maintenance costs each year. In the field of electronic device manufacturing, oxygen molecules react with silicon-based materials in high-temperature processes to generate oxide defects, resulting in a decrease in chip yield. At the same time, the food and pharmaceutical industries are also facing challenges brought by oxygen: studies have shown that strawberries deteriorate rapidly after harvest, mainly due to factors such as microbial contamination, and low oxygen can reduce the respiration rate of strawberries and prevent the growth of aerobic microorganisms, thereby extending the shelf life of strawberries (Priyadarshi R, Jayakumar A, De Souza CK, et al. Advances in strawberry postharvest preservation and packaging: A comprehensive review [J]. Comprehensive Reviews in Food Science and Food Safety, 2024, 23 (4): e13417.).

[0003] To cope with the negative impact of oxygen, traditional deoxygenation technology has long relied on two major systems: chemical adsorption and inert gas replacement. The first is a chemical adsorption method based on iron oxide or ascorbic acid derivatives, but this type of consumables has an irreversible passivation problem, forming metal oxide residues after a single use, and the global hazardous waste generated each year is as high as 120,000 tons; the second is the nitrogen replacement method, which can quickly establish an inert environment, but requires continuous gas supply to maintain. According to statistics from the International Food Engineering Association, the energy consumption cost of production lines using this technology will increase by 35%, and there is a risk of gas purity fluctuations.

[0004] Electrochemical deoxygenation achieves directional conversion of dissolved oxygen through oxygen reduction reaction (ORR), and its core advantages lie in high efficiency and controllability. Taking NiCoFe electrode as an example, the catalyst prepared by one-step electrodeposition can convert O2 through a four-electron pathway (O2+4H + +4e -→2H2O) has the characteristics of high efficiency, simple equipment, flexible operation and easy automation, and has attracted widespread attention. (Wang Ximin, Yu Dezhe, Xie Chenxin, Zhu Tianzhen, Qian Guanglei, Yao Guangyuan. Research on the preparation of NiCoFe electrode by one-step electrodeposition for electrochemical deoxygenation [J]. Industrial Water Treatment: 1-15.) However, the large-scale application of electrochemical deoxygenation technology still faces significant bottlenecks: ORR catalysts are mostly precious metals, their catalyst costs are high, and there are problems such as catalyst poisoning and deactivation after continuous operation. (Polyanskii, LN, Gorshkov, VS, Vakhnin, DD et al. Sorption-membrane system for deep deoxygenation of water.

[0005] Nanotechnol Russia 10, 558–564 (2015)). Therefore, based on the above discussion, exploring a more efficient, stable and low-cost electrochemical deoxygenation method will be the main goal in the field of electrochemical deoxygenation. Summary of the invention

[0006] The purpose of the present invention is to solve the problems of incomplete deoxidation, high catalyst cost and short stabilization time of existing electrochemical technology, and propose an electrochemical deoxidation system and its application. The electrochemical deoxidation system provided by the present invention has fast deoxidation rate, good stability and low cost.

[0007] The purpose of the present invention is achieved by at least one of the following technical solutions.

[0008] A method for establishing an electrochemical deoxygenation system, characterized in that the establishment of the deoxygenation system mainly includes the following steps:

[0009] (1) A two-electrode flow electrolytic cell is used as an electrolytic cell, cathode and anode electrolytes are prepared, and the electrolytes are separated by a proton exchange membrane;

[0010] (2) Connect the electrolytic cell to a sealed container, use a pump to accelerate air circulation and electrolyte flow, and operate at a constant voltage.

[0011] Furthermore, in step (1), the anode electrolyte is a dilute phosphoric acid solution, and the concentration of the dilute phosphoric acid solution is less than 1 mol / L.

[0012] Furthermore, in step (1), the cathode electrolyte is a tungstosilicic acid solution with a concentration lower than 0.5 mol / L. 10 )4]·xH2O) as the reaction medium, the higher the concentration of silicotungstic acid, the faster the deoxygenation rate.

[0013] Preferably, the concentration of the dilute phosphoric acid solution is 0.2 mol / L, the volume is 100 mL, the concentration of the silicotungstic acid solution is 0.05 mol / L, and the stirring rate of the silicotungstic acid is 2000 rpm.

[0014] Furthermore, the cathode electrolyte has the same concentration as the anode electrolyte.

[0015] Furthermore, in step (1), the anode catalyst is an OER catalyst suitable for an acidic environment, such as iridium oxide or ruthenium oxide.

[0016] Furthermore, in step (1), the cathode is a porous conductive medium such as carbon felt, graphite felt, etc.

[0017] Furthermore, in step (2), the flow rate of the pump is 0 to 100 mL / min, preferably 20 ml / min.

[0018] Furthermore, in step (2), the constant voltage is -1.5 to -1.8 volts (based on a reversible hydrogen electrode), preferably -1.75 volts (based on a reversible hydrogen electrode).

[0019] The electrochemical deoxygenation system constructed by the establishment method described in the present invention is applied to deoxygenation of closed systems of different volumes.

[0020] Specifically, at -1.75 volts (based on a reversible hydrogen electrode) and a closed system volume of 30 mL to 4 L, the oxygen content in the air can be reduced from 21% to below 5% after 42 minutes to 26 hours, and can be reduced to below 1% after 350 minutes to 40 hours.

[0021] Compared with the prior art, the advantages of the present invention are: 1. low cost, the reduced product (H5[SiW 12 O 40 ] and H6[SiW 12 O 40 ]) The spontaneous reaction with oxygen ensures continuous operation without the need for precious metal catalysts; ② Low energy consumption, the gas-phase oxygen concentration can be reduced from 21% to below 0.7% at an operating voltage of -1.75V ③ Environmentally friendly, the product after the system is operated is mainly water, so there is little pollution during the entire operation process. ④ Good stability, after multiple operations, the system still maintains the same deoxygenation efficiency. Compared with traditional technologies, this system has the advantages of low energy consumption (working potential -1.75V), strong stability, environmental friendliness and strong universality. This deoxygenation solution that is both economical and stable provides a new technical option for low-oxygen demand scenarios such as food preservation, pharmaceutical manufacturing, semiconductor packaging, and lithium battery production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1This is a schematic diagram of the device connection in Example 1;

[0023] Figure 2 It is a graph of deoxygenation rate at different potentials of the system shown in Example 1;

[0024] Figure 3 is a diagram of the system deoxygenation rate shown in Example 2;

[0025] Figure 4 is a diagram of the system deoxygenation rate shown in Example 3;

[0026] Figure 5 is a diagram of the deoxygenation rate of the system shown in Example 4;

[0027] Figure 6 It is a graph of deoxygenation rate at different potentials of the system shown in Example 5;

[0028] Figure 7 is a diagram of the system deoxygenation rate shown in Example 6;

[0029] Figure 8 is a diagram of the system deoxygenation rate shown in Example 7;

[0030] Fig. 9 is a graph of deoxygenation rates at different temperatures for the system shown in Example 8;

[0031] Fig.10 This is a diagram of the system deoxygenation rate shown in Example 9. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention is further described below in conjunction with examples, but the implementation and protection of the present invention are not limited thereto. It should be noted that if there are processes that are not particularly described in detail below, they can be implemented or understood by those skilled in the art with reference to the prior art. If the manufacturer of the reagents or instruments used is not indicated, they are deemed to be conventional products that can be purchased commercially.

[0033] Example 1

[0034] A small volume deoxygenation system is established, comprising the following steps:

[0035] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell, the anode catalyst is an iridium titanium mesh, and the cathode is a carbon felt, which are separated by a proton exchange membrane.

[0036] (2) A dilute phosphoric acid solution was used as the anolyte, and silicotungstic acid was added to the dilute phosphoric acid solution and stirred.

[0037] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage, such as Figure 1 shown.

[0038] In step (2), the concentration of the dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the silicotungstic acid solution is 0.05 mol / L and the volume is 30 mL.

[0039] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0040] In step (3), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0041] In step (3), the volume of the sealed container is 50 mL.

[0042] The electrochemical system used in Example 1 is as follows Figure 1 As shown, Figure 2 It can be seen that at -1.75 volts (based on the reversible hydrogen electrode), the oxygen content in the air can drop from 20.41% to below 5% after 42 minutes.

[0043] Example 2

[0044] A large volume deoxygenation system is established, comprising the following steps:

[0045] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell, the anode catalyst is an iridium titanium mesh, and the cathode is a carbon felt, which are separated by a proton exchange membrane.

[0046] (2) A dilute phosphoric acid solution was used as the anolyte, and silicotungstic acid was added to the dilute phosphoric acid solution and stirred.

[0047] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0048] In step (2), the concentration of the dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the silicotungstic acid solution is 0.05 mol / L and the volume is 500 mL.

[0049] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0050] In step (3), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0051] In step (3), the volume of the sealed container is 1000 mL.

[0052] The electrochemical system used in Example 2 is shown in the figure. Figure 3It can be seen that at -1.75 volts (based on the reversible hydrogen electrode), the oxygen content in the air can be reduced from 21% to below 5% after 160 minutes, and can be reduced to below 1% after 350 minutes.

[0053] Example 3

[0054] A large volume deoxygenation system is established, comprising the following steps:

[0055] (1) A flow electrolytic cell is used as the electrolytic cell, the anode catalyst is an iridium titanium mesh, and the cathode is a carbon felt, which are separated by a proton exchange membrane.

[0056] (2) A dilute phosphoric acid solution was used as the anolyte, and silicotungstic acid was added to the dilute phosphoric acid solution and stirred.

[0057] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0058] In step (2), the concentration of the dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the silicotungstic acid solution is 0.05 mol / L and the volume is 500 mL.

[0059] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0060] In step (3), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0061] In step (3), the volume of the sealed container is 4 liters and the operation time is 5 days.

[0062] The electrochemical system used in Example 3 is shown in the figure. Figure 4 It can be seen that at -1.75 volts (based on the reversible hydrogen electrode), the oxygen content in the air can drop from 21% to below 5% after 26 hours, and can drop to below 1% after about 40 hours, and the closed system can be maintained for a long time to keep the oxygen content below 1%.

[0063] Example 4

[0064] An electrochemical deoxidation method comprises the following steps:

[0065] (1) A two-electrode flow electrolysis cell was used as the electrolytic cell. The anode catalyst was an iridium titanium mesh and the cathode catalyst was a commercial 20% Pt / C catalyst, which were separated by a proton exchange membrane.

[0066] (2) Both the anode and cathode electrolytes use dilute phosphoric acid solution.

[0067] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0068] In step (2), the concentration of the anode dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the cathode dilute phosphoric acid solution is 0.2 mol / L and the volume is 30 mL.

[0069] In step (3), the flow rates of the pumps used for the flow of the electrolyte and air were set to 20 ml / min, and the voltages were respectively -1.1, -1.3, and -1.5 volts (based on the reversible hydrogen electrode).

[0070] In step (3), the volume of the sealed container is 50 mL.

[0071] The electrochemical system used in Example 4 is shown in the figure. Figure 5 It can be seen that at -1.1 volts (based on the reversible hydrogen electrode), the oxygen content in the air dropped from 21% to 13.76% after 99 minutes; at -1.3 volts (based on the reversible hydrogen electrode), the oxygen content in the air dropped from 21% to 12.2% after 99 minutes; at -1.5 volts (based on the reversible hydrogen electrode), the oxygen content in the air dropped from 21% to 7.03% after 99 minutes.

[0072] Example 5

[0073] An electrochemical deoxidation method comprises the following steps:

[0074] (1) A two-electrode flow electrolytic cell was used as the electrolytic cell, an iridium-titanium mesh was used as the anode catalyst, and a carbon paper (GDL-3250) was used as the cathode electrode, which was separated by a proton exchange membrane.

[0075] (2) A dilute phosphoric acid solution was used as the anolyte, and silicotungstic acid was added to the dilute phosphoric acid solution and stirred.

[0076] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0077] In step (2), the concentration of the dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the silicotungstic acid solution is 0.05 mol / L and the volume is 30 mL.

[0078] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0079] In step (3), the flow rate of the pumps used for the flow of the electrolyte and the air is set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode). Further, the volume of the sealed container in step (3) is 50 mL.

[0080] The electrochemical system used in Example 5 is adopted, such as Figure 6 As shown, at -1.7 volts (based on the reversible hydrogen electrode), the oxygen content in the air dropped from 20.41% to 20.23% after 47 minutes.

[0081] Example 6

[0082] An electrochemical deoxidation method comprises the following steps:

[0083] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell, an iridium-titanium oxide mesh is used as the anode catalyst, and a carbon felt is used as the cathode electrode, which are separated by a proton exchange membrane.

[0084] (2) Both the anode and cathode electrolytes use dilute phosphoric acid solution.

[0085] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0086] In step (2), the concentration of the anode dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the cathode dilute phosphoric acid solution is 0.2 mol / L and the volume is 30 mL.

[0087] In step (3), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0088] In step (3), the volume of the sealed container is 50 mL.

[0089] The electrochemical system used in Example 6 is used, such as Figure 7 As shown, at -1.7 volts (based on the reversible hydrogen electrode), the oxygen content in the air dropped from 20.84% ​​to 19.4% after 47 minutes.

[0090] Example 7

[0091] An electrochemical deoxidation method comprises the following steps:

[0092] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell, an iridium-titanium oxide mesh is used as the anode catalyst, and a carbon felt is used as the cathode electrode, which are separated by a proton exchange membrane.

[0093] (2) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0094] In step (2), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.7 volts (based on the reversible hydrogen electrode).

[0095] In step (3), the volume of the sealed container is 50 mL.

[0096] The electrochemical system used in Example 7 is used, such as Figure 8 As shown, at -1.7 volts (based on the reversible hydrogen electrode), the oxygen content in the air dropped from 20.4% to 20.29% after 47 minutes.

[0097] Example 8

[0098] A deoxygenation system is established, comprising the following steps:

[0099] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell, the anode catalyst is an iridium titanium mesh, and the cathode is a carbon felt, which are separated by a proton exchange membrane.

[0100] (2) A dilute phosphoric acid solution was used as the anolyte, and silicotungstic acid was added to the dilute phosphoric acid solution and stirred.

[0101] (3) Heat in a water bath to increase the temperature of the silicotungstic acid solution.

[0102] (4) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0103] In step (2), the concentration of the dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the silicotungstic acid solution is 0.05 mol / L and the volume is 30 mL.

[0104] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0105] In step (3), the temperatures of the silicotungstic acid are 40°C, 50°C, and 60°C, respectively.

[0106] Furthermore, in step (4), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode standard).

[0107] In step (4), the volume of the sealed container is 50 mL.

[0108] The electrochemical system used in Example 8 is as follows Fig. 9 As shown, at -1.75 volts (based on the reversible hydrogen electrode), at 40°C, the oxygen content dropped from 20.62% to 4.98% after 42 minutes; at 50°C, the oxygen content dropped from 20.62% to 4.99% after 40 minutes; at 60°C, the oxygen content dropped from 20.57% to 4.96% after 36 minutes.

[0109] Example 9

[0110] A deoxygenation system is established, comprising the following steps:

[0111] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell, the anode catalyst is an iridium titanium mesh, and the cathode is a carbon felt, which are separated by a proton exchange membrane.

[0112] (2) A dilute phosphoric acid solution was used as the anolyte, and silicotungstic acid was added to the dilute phosphoric acid solution and stirred.

[0113] (3) Connect the electrolytic cell and pump to a closed container and operate at a constant voltage.

[0114] (4) After deoxygenation, the silicotungstic acid solution is placed in air for a period of time and deoxygenated again according to the above method.

[0115] In step (2), the concentration of the dilute phosphoric acid solution is 0.2 mol / L and the volume is 100 mL, and the concentration of the silicotungstic acid solution is 0.05 mol / L and the volume is 30 mL.

[0116] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0117] In step (3), the flow rates of the pumps used for the flow of the electrolyte and air are both set to 20 ml / min, and the voltage is -1.7 volts (based on the reversible hydrogen electrode).

[0118] In step (3), the volume of the sealed container is 50 mL.

[0119] In step (4), the silicotungstic acid solution is placed for a period of time, specifically, the silicotungstic acid solution (blue-purple) after electro-reduction is naturally placed indoors for a period of time until it is completely oxidized into a transparent solution in contact with air.

[0120] The electrochemical system used in Example 9 is as follows Fig.10 As shown, at -1.7 volts (based on the reversible hydrogen electrode), the oxygen content dropped from 20.42% to below 5% after 48 minutes.

Claims

1. A method for establishing an electrochemical deoxygenation system, characterized in that: The deoxygenation system is established mainly including the following steps: (1) A two-electrode flow electrolytic cell is used as an electrolytic cell, cathode and anode electrolytes are prepared, and the electrolytes are separated by a proton exchange membrane; (2) Connect the electrolytic cell to a sealed container, use a pump to accelerate air circulation and electrolyte flow, and operate at a constant voltage.

2. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: In step (1), the anolyte is a dilute phosphoric acid solution, and the concentration of the dilute phosphoric acid solution is less than 1 mol / L.

3. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: In step (1), the cathode electrolyte is a tungstosilicic acid solution with a concentration lower than 0.5 mol / L.

4. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: The concentration of the catholyte is the same as that of the anolyte.

5. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: In step (1), the anode catalyst is iridium oxide or ruthenium oxide.

6. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: In step (1), the cathode is carbon felt or graphite felt.

7. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: In step (2), the flow rate of the pump is 0 to 100 mL / min.

8. The method for establishing an electrochemical deoxygenation system according to claim 1, characterized in that: In step (2), the constant voltage is -1.5 to -1.8 volts (based on the reversible hydrogen electrode).

9. The electrochemical deoxygenation system constructed by the method according to any one of claims 1 to 8 is applied to deoxygenate closed systems of different volumes.

10. The use according to claim 9, characterized in that: At -1.75 volts (based on a reversible hydrogen electrode) and a closed system volume of 30 mL to 4 L, the oxygen content in the air can drop from 21% to below 5% after 42 minutes to 26 hours, and can drop to below 1% after 350 minutes to 40 hours.

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