Method for establishing electrochemical oxygen removal system and application thereof

Abstract

The application discloses a kind of establishment method of electrochemical oxygen removal system and its application.The specific method operation is as follows: silicotungstic acid is dissolved in dilute phosphoric acid solution as cathode electrolyte, anode electrolyte uses the same concentration phosphoric acid solution, and electrochemical reaction is carried out in flow electrolytic cell.The reaction method provided by the application has simple process, low cost, good oxygen removal performance and stability.In 50mL of sealed container, with reversible hydrogen electrode as standard, oxygen content can be reduced to below 5% in 42 minutes at-1.75 volts, and the oxygen removal capacity does not decrease in 1000min of multiple cycles;And when the volume of the container is replaced by 500mL and 3.5L of large volume container, the system can also reduce the oxygen content to below 5% after 4 hours and 26 hours respectively.

Description

Technical Field

[0001] This invention belongs to the field of electrochemistry, specifically relating to the establishment of an electrochemical deoxygenation system. Background Technology

[0002] In industrial boilers, oilfield extraction, pharmaceutical research, and electronic device manufacturing, as well as in daily life, the presence of oxygen often causes a series of problems, including equipment corrosion, well blockage, decreased product quality, and reduced food and drug quality. Industrially, the corrosion rate of carbon steel pipes in oxygen-containing water environments can reach 0.12 mm / year, with the mechanism stemming from the Fe→Fe²⁺ reaction. + +2e - The anodizing reaction not only shortens equipment lifespan but also increases global industrial maintenance costs by more than $2 billion annually. 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 also face challenges from oxygen: studies have shown that strawberries spoil rapidly after harvest, mainly due to factors such as microbial contamination, while 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, DeSouza 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 address the negative impacts of oxygen, traditional deoxygenation technologies have long relied on two main systems: chemical adsorption and inert gas replacement. The first is chemical adsorption based on iron oxide or ascorbic acid derivatives, but these consumables suffer from irreversible passivation, forming metal oxide residues after a single use, resulting in up to 120,000 tons of hazardous waste globally each year. The second is nitrogen replacement, which can quickly establish an inert environment, but requires a continuous gas supply to maintain it. According to statistics from the International Food Engineering Association, production lines using this technology will increase energy costs by 35%, and there is also a risk of fluctuations in gas purity.

[0004] Electrochemical deoxygenation achieves the directional conversion of dissolved oxygen through the oxygen reduction reaction (ORR), with its core advantages lying in its high efficiency and controllability. Taking a NiCoFe electrode as an example, a catalyst prepared by a one-step electrodeposition method can deoxygenate O2 through a four-electron pathway (O2 + 4H+). + +4e -→2H2O) high-efficiency reduction has attracted widespread attention due to its high efficiency, simple equipment, flexible operation, and ease of automation. (Wang Ximin, Yu Deze, Xie Chenxin, Zhu Tianzhen, Qian Guanglei, Yao Guangyuan. Research on the preparation of NiCoFe electrodes for electrochemical deoxygenation by one-step electrodeposition method [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, which have high costs, and problems such as catalyst poisoning and deactivation occur after continuous operation. (Polyanskii, LN, Gorshkov, VS, Vakhnin, DD et al. Sorption-membrane system for deep deoxygenation of water. Nanotechnol Russia 10, 558–564 (2015)). Therefore, based on the above discussion, exploring a more efficient, stable, and lower-cost electrochemical deoxygenation method will be the main goal in the field of electrochemical deoxygenation. Summary of the Invention

[0005] The purpose of this invention is to address the problems of incomplete oxygen removal, high catalyst cost, and short stabilization time in existing electrochemical technologies, and to propose the establishment and application of an electrochemical oxygen removal system. The electrochemical oxygen removal system provided by this invention features fast oxygen removal rate, good stability, and low cost.

[0006] The objective of this invention is achieved by at least one of the following technical solutions.

[0007] A method for establishing an electrochemical deoxygenation system, characterized in that the establishment of the deoxygenation system mainly includes the following steps:

[0008] (1) Use a two-electrode flow electrolytic cell as an electrolytic cell, prepare cathode and anode electrolytes, and separate them by a proton exchange membrane;

[0009] (2) Connect the electrolytic cell to a sealed container, use a pump to accelerate air circulation and electrolyte flow, and operate under constant voltage.

[0010] Further, in step (1), the anolyte is a dilute phosphoric acid solution with a concentration of less than 1 mol / L.

[0011] Further, in step (1), the cathode electrolyte is a tungstic acid solution with a concentration lower than 0.5 mol / L. In this invention, silicotungstic acid (H4[Si(W3O4)2]) is used. 10 As a reaction medium, the higher the concentration of silicotungstic acid, the faster the deoxygenation rate.

[0012] Preferably, the concentration of the dilute phosphoric acid solution is 0.2 mol / L and 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 solution is 2000 rpm.

[0013] Furthermore, the concentration of the cathode electrolyte is the same as that of the anolyte.

[0014] Furthermore, in step (1), the anode catalyst is an OER catalyst suitable for acidic environments, such as iridium oxide or ruthenium oxide.

[0015] Furthermore, in step (1), the cathode is a porous conductive medium such as carbon felt or graphite felt.

[0016] Furthermore, in step (2), the flow rate of the pump is 0 to 100 mL / min, preferably 20 mL / min.

[0017] Further, in step (2), the constant voltage is -1.5 to -1.8 volts (based on the reversible hydrogen electrode), preferably -1.75 volts (based on the reversible hydrogen electrode).

[0018] The electrochemical deoxygenation system constructed by the method described in this invention can be applied to deoxygenation of closed systems of different volumes.

[0019] 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 can be reduced from 21% in the air to below 5% in 42 minutes to 26 hours, and to below 1% in 350 minutes to 40 hours.

[0020] Compared with the prior art, the advantages of the present invention are: ① low cost, and the reduced product of silicotungstic acid solution (H5[SiW) 12 O 40 ] and H6[SiW 12 O 40 The system exhibits several advantages: 1) Spontaneous reaction with oxygen ensures continuous operation without the need for precious metal catalysts; 2) Low energy consumption, reducing gaseous oxygen concentration from 21% to below 0.7% at an operating voltage of -1.75 V; 3) Environmental friendliness, with water being the primary byproduct, resulting in minimal pollution throughout operation; and 4) High stability, maintaining the same deoxygenation efficiency even after multiple runs. Compared to traditional technologies, this system boasts advantages such as low energy consumption (operating potential -1.75 V), high stability, environmental friendliness, and broad applicability. This economical and stable deoxygenation solution provides a new technological option for low-oxygen applications in food preservation, pharmaceutical manufacturing, semiconductor packaging, and lithium battery production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the device connection in Example 1;

[0022] Figure 2 The diagram shows the deoxygenation rate of the system at different potentials as shown in Example 1.

[0023] Figure 3 The system deoxygenation rate diagram shown in Example 2;

[0024] Figure 4 The system deoxygenation rate diagram shown in Example 3;

[0025] Figure 5 The system deoxygenation rate diagram shown in Example 4;

[0026] Figure 6 The diagram shows the deoxygenation rate of the system at different potentials as shown in Example 5.

[0027] Figure 7 The system deoxygenation rate diagram shown in Example 6;

[0028] Figure 8 This is a graph showing the deoxygenation rate of the system shown in Example 7 at different temperatures;

[0029] Figure 9 The diagram shows the system deoxygenation rate in Example 8. Detailed Implementation

[0030] The following examples further illustrate specific implementations of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0031] Example 1

[0032] A small-volume deoxygenation system is established, comprising the following steps:

[0033] (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 is separated by a proton exchange membrane.

[0034] (2) The anolyte is a dilute phosphoric acid solution, and the cathode electrolyte is made by adding silicotungstic acid to the dilute phosphoric acid solution and stirring.

[0035] (3) Connect the electrolytic cell, pump, and sealed container, and operate under constant voltage, such as... Figure 1 As shown.

[0036] 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.

[0037] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0038] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0039] In step (3), the volume of the sealed container is 50 mL.

[0040] The electrochemical system used in Example 1, such as Figure 1 As shown, Figure 2 As can be seen, at -1.75 volts (based on the reversible hydrogen electrode), the oxygen content can drop from 20.41% in the air to below 5% after 42 minutes.

[0041] Example 2

[0042] The establishment of a large-volume deoxygenation system includes the following steps:

[0043] (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 is separated by a proton exchange membrane.

[0044] (2) The anolyte is a dilute phosphoric acid solution, and the cathode electrolyte is made by adding silicotungstic acid to the dilute phosphoric acid solution and stirring.

[0045] (3) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0046] 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.

[0047] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0048] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0049] In step (3), the volume of the sealed container is 1000 mL.

[0050] 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 can drop from 21% in the air to below 5% after 160 minutes, and to below 1% after 350 minutes.

[0051] Example 3

[0052] The establishment of a large-volume deoxygenation system includes the following steps:

[0053] (1) A flowing electrolytic cell is used as the electrolytic cell, with iridium titanium oxide mesh as the anode catalyst and carbon felt as the cathode, separated by a proton exchange membrane.

[0054] (2) The anolyte is a dilute phosphoric acid solution, and the cathode electrolyte is made by adding silicotungstic acid to the dilute phosphoric acid solution and stirring.

[0055] (3) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0056] 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.

[0057] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0058] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0059] In step (3), the sealed container has a volume of 4 liters and an operating time of 5 days.

[0060] The electrochemical system used in Example 3 is shown in the figure. Figure 4 As can be seen, at -1.75 volts (based on the reversible hydrogen electrode), the oxygen content can be reduced from 21% in the air to below 5% after 26 hours, and to below 1% after about 40 hours. It can also maintain operation for a long time to keep the oxygen content of the closed system below 1%.

[0061] Example 4

[0062] An electrochemical deoxygenation method includes the following steps:

[0063] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell. The anode catalyst is an iridium titanium mesh, and the cathode catalyst is a commercial 20% Pt / C catalyst, which are separated by a proton exchange membrane.

[0064] (2) Both the anode and cathode electrolytes use dilute phosphoric acid solution.

[0065] (3) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0066] In step (2), the concentration of the dilute phosphoric acid solution at the anode is 0.2 mol / L and the volume is 100 mL, and the concentration of the dilute phosphoric acid solution at the cathode is 0.2 mol / L and the volume is 30 mL.

[0067] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.1, -1.3, and -1.5 volts respectively (based on the reversible hydrogen electrode).

[0068] In step (3), the volume of the sealed container is 50 mL.

[0069] The electrochemical system used in Example 4 is shown in the figure. Figure 5 As can be seen, at -1.1 volts (based on the reversible hydrogen electrode), the oxygen content decreased from 21% in the air to 13.76% after 99 minutes; at -1.3 volts (based on the reversible hydrogen electrode), the oxygen content decreased from 21% in the air to 12.2% after 99 minutes; and at -1.5 volts (based on the reversible hydrogen electrode), the oxygen content decreased from 21% in the air to 7.03% after 99 minutes.

[0070] Example 5

[0071] An electrochemical deoxygenation method includes the following steps:

[0072] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell. The anode catalyst is iridium titanium mesh, and the cathode is carbon paper (GDL-3250) as the electrode, separated by a proton exchange membrane.

[0073] (2) The anolyte is a dilute phosphoric acid solution, and the cathode electrolyte is made by adding silicotungstic acid to the dilute phosphoric acid solution and stirring.

[0074] (3) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0075] 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.

[0076] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0077] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.75 volts (based on a reversible hydrogen electrode). Further, the volume of the sealed container in step (3) is 50 mL.

[0078] Using the electrochemical system employed in Example 5, such as Figure 6 As shown, at -1.7 volts (based on a reversible hydrogen electrode), the oxygen content decreased from 20.41% in the air to 20.23% after 47 minutes.

[0079] Example 6

[0080] An electrochemical deoxygenation method includes the following steps:

[0081] (1) A two-electrode flow electrolytic cell is used as the electrolytic cell. The anode catalyst is an iridium titanium mesh, and the cathode electrode is a carbon felt, which is separated by a proton exchange membrane.

[0082] (2) Both the anode and cathode electrolytes use dilute phosphoric acid solution.

[0083] (3) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0084] In step (2), the concentration of the dilute phosphoric acid solution at the anode is 0.2 mol / L and the volume is 100 mL, and the concentration of the dilute phosphoric acid solution at the cathode is 0.2 mol / L and the volume is 30 mL.

[0085] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0086] In step (3), the volume of the sealed container is 50 mL.

[0087] Using the electrochemical system employed in Example 6, such as Figure 7 As shown, at -1.7 volts (based on a reversible hydrogen electrode), the oxygen content decreased from 20.84% ​​in the air to 19.4% after 47 minutes.

[0088] Example 7

[0089] An oxygen removal system is established, comprising the following steps:

[0090] (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 is separated by a proton exchange membrane.

[0091] (2) The anolyte is a dilute phosphoric acid solution, and the cathode electrolyte is made by adding silicotungstic acid to the dilute phosphoric acid solution and stirring.

[0092] (3) Water bath heating to raise the temperature of silicotungstic acid solution.

[0093] (4) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0094] 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.

[0095] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0096] In step (3), the temperatures of the silicotungstic acid are 40°C, 50°C, and 60°C, respectively.

[0097] Furthermore, in step (4), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.75 volts (based on the reversible hydrogen electrode).

[0098] In step (4), the volume of the sealed container is 50 mL.

[0099] The electrochemical system used in Example 8, such as Figure 8 As shown, at -1.75 volts (based on a reversible hydrogen electrode), at 40°C, the oxygen content decreased from 20.62% to 4.98% after 42 minutes; at 50°C, the oxygen content decreased from 20.62% to 4.99% after 40 minutes; and at 60°C, the oxygen content decreased from 20.57% to 4.96% after 36 minutes.

[0100] Example 8

[0101] An oxygen removal system is established, comprising the following steps:

[0102] (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 is separated by a proton exchange membrane.

[0103] (2) The anolyte is a dilute phosphoric acid solution, and the cathode electrolyte is made by adding silicotungstic acid to the dilute phosphoric acid solution and stirring.

[0104] (3) Connect the electrolytic cell, pump and sealed container and operate under constant voltage.

[0105] (4) After the deoxygenation is completed, the silicotungstic acid solution is left in the air for a period of time, and then deoxygenated again in the same way as described above.

[0106] 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.

[0107] In step (2), the stirring rate of the silicotungstic acid is 2000 rpm.

[0108] In step (3), the flow rate of the pumps used for the electrolyte and air flow is set to 20 ml / min, and the voltage is -1.7 volts (based on the reversible hydrogen electrode).

[0109] In step (3), the volume of the sealed container is 50 mL.

[0110] In step (4), the silicotungstic acid solution that has been left for a period of time is specifically placed indoors for a period of time after electroreduction (blue-purple) until it is completely oxidized into a transparent solution by contact with air.

[0111] The electrochemical system used in Example 8, such as Figure 9 As shown, at -1.7 volts (based on a reversible hydrogen electrode), the oxygen content is 20%.

Claims

1. A method for establishing an electrochemical deoxygenation system, characterized in that, The establishment of the deoxygenation system mainly includes the following steps: (1) A two-electrode flow electrolytic cell is used as an electrolytic cell, and cathode and anode electrolytes are prepared and separated by a proton exchange membrane; the cathode electrolyte is a tungstic acid solution with a concentration of less than 0.5 mol / L; the cathode is a porous conductive medium carbon felt or graphite felt. (2) Connect the electrolytic cell to a sealed container, use a pump to accelerate air circulation and electrolyte flow, and operate under 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 with a concentration of less than 1 mol / L.

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

4. 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.

5. 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.

6. 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, using the reversible hydrogen electrode as a standard.

7. The electrochemical deoxygenation system constructed by the method according to any one of claims 1 to 6 is applied to deoxygenation of closed systems of different volumes.

8. The application according to claim 7, characterized in that, Using a reversible hydrogen electrode as a standard, at -1.75 volts and a closed system volume of 30 mL to 4 L, the oxygen content can be reduced from 21% in the air to below 5% in 42 minutes to 26 hours, and to below 1% in 350 minutes to 40 hours.

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