A method for removing sulfur ions from water by coupling piezoelectric catalytic fuel cells with oxygen oxidation

Abstract

The present invention provides a method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation, belonging to the field of wastewater treatment technology. The method is characterized by preparing a Fe@MoS2 / CFC piezoelectric catalytic electrode through a one-step hydrothermal method, and constructing a piezoelectric catalytic fuel cell-enhanced air oxidation system based on this electrode. The effect and benefit of the present invention is that the piezoelectric catalytic fuel cell can remove 91% (~14.7 mg) of sulfur ions (S) in 1.5 hours by simply exposing the piezoelectric fuel cell to air. 2‑ ), the system has excellent piezoelectric catalytic activity, is efficient and green in removing sulfur ions, and has good application prospects in the fields of catalytic fuel cells and advanced oxidation wastewater treatment.

Description

Technical Field

[0001] The present invention provides a construction and application method of a fuel cell for piezoelectrically enhanced oxygen oxidation desulfurization, which belongs to the technical field of wastewater treatment and relates to the construction of a piezoelectric fuel cell, and in particular to a method for enhancing the oxidation of sulfides in water by oxygen exposed to air through the piezoelectric effect. Background Art

[0002] In recent years, with the rapid development of science and technology, the discharge of industrial, domestic, and agricultural wastewater has led to excessive sulfide levels in groundwater. Soluble sulfides are corrosive and easily damage steel, concrete, and other materials, causing economic losses and posing safety risks. Sulfides also easily convert into hydrogen sulfide (H2S) in water, producing a foul odor that harms the human respiratory and nervous systems, increases fish morbidity and mortality, and forms complexes with heavy metals, inhibiting plant root growth. To improve water quality, ensure drinking water safety, and extend the life of equipment and pipelines, effective measures must be taken to remove sulfides from groundwater. Traditional treatment methods include filtration, chemical precipitation, and biological methods. However, filtration is costly and has low selectivity; chemical precipitation requires the addition of chemicals, which can easily cause secondary contamination; and biological methods have stringent temperature and pH requirements and are slow to react.

[0003] Chemical oxidation involves introducing an oxidizing gas, such as oxygen (O2), chlorine (Cl2), or ozone (O3), into sulfur-containing wastewater to oxidize sulfides into elemental sulfur or sulfates. This process utilizes oxygen in the air to treat sulfides without the addition of additional chemicals, resulting in lower costs and less environmental impact. However, at room temperature and pressure, oxygen has a low oxidizing capacity, resulting in a weak reaction with sulfides and low removal efficiency. Improving the desulfurization capacity of oxygen oxidation is of practical significance.

[0004] Piezocatalysis is a phenomenon in which, when mechanically deformed, positive and negative charges in semiconductor materials with non-centrosymmetric structures migrate in opposite directions to the surface, causing redox reactions with pollutants in water. This process is environmentally friendly because it can be stimulated by renewable energy sources, such as wind, water flow, or footsteps. Because powdered catalysts are difficult to recycle, in situ synthesis of the catalyst on a conductive substrate to create a piezocatalytic electrode not only fully exposes the active sites but also stabilizes the catalyst.

[0005] To further enhance piezoelectric performance, this invention constructs a piezoelectric catalytic fuel cell for the first time. By biasing the electrodes, electrons generated by the piezoelectric anode are transferred to the cathode via an external circuit, promoting the separation of positive and negative charges in the material. Aeration is also used to provide the system with dissolved oxygen and mechanical force generated by water flow / bubbles. This system can be applied not only to desulfurization but also to the removal of difficult-to-degrade organic pollutants. Currently, there are no reports on the construction of piezoelectric catalytic fuel cells or on the use of the piezoelectric effect to enhance oxygen oxidation desulfurization. Summary of the Invention

[0006] The present invention addresses the problems of difficult treatment of sulfide pollution in wastewater and low oxygen oxidation desulfurization efficiency, and constructs a piezoelectric catalytic fuel cell system that can desulfurize only through aeration, that is, a method of enhancing oxygen oxidation desulfurization using the piezoelectric catalytic effect.

[0007] The technical solution of the present invention:

[0008] A method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation comprises the following steps:

[0009] The piezoelectric anode and cathode are connected through an external circuit and placed in an insulating material reactor. The waste solution to be treated is used as the electrolyte. The aeration head is inserted into the bottom of the reactor to provide dissolved oxygen and mechanical force. The reaction begins when the aeration pump is turned on. The power generation and sulfur ion (S) production are regulated by adjusting the aeration intensity, the temperature of the waste solution to be treated, and the external resistance of the external circuit. 2- ) removal effect.

[0010] Further, preparation of Fe@MoS2 / CFC piezoelectric anode:

[0011] A clean carbon fiber cloth (CFC) removed from the reactor using anhydrous ethanol was immersed in a seed solution containing Na2MoO4·2H2O and CH4N2S. After soaking for a period of time, the solution was dried in a vacuum drying oven to obtain a seed layer CFC. FeSO4·xH2O, Na2MoO4·2H2O, and CH4N2S were added to deionized water and stirred thoroughly. The mixed solution was then poured into a reactor. The seed layer CFC was placed in the reactor containing the mixed solution for a hydrothermal reaction. After the reaction was complete, the reactor was allowed to cool to room temperature. The Fe@MoS2-loaded CFC was removed, rinsed repeatedly with deionized water, and thoroughly dried in a vacuum drying oven to obtain a Fe@MoS2 / CFC piezoelectric catalytic electrode.

[0012] Furthermore, the molar concentration of S in the seed solution is 0.01M-0.03M, which is 2-3 times that of Mo.

[0013] Furthermore, the clean CFC is soaked in the seed solution for 0.5 h to 2 h.

[0014] Furthermore, in a mixed solution of FeSO4·xH2O, Na2MoO4·2H2O and CH4N2S, the molar concentration ratio of Fe and Mo is less than or equal to 1:1, and the molar concentration of S is 0.15M-0.25M, which is 2-3 times the sum of the molar concentrations of Fe and Mo.

[0015] Furthermore, the addition ratio of seed layer CFC to mixed solution is 1cm2 :70mL-1cm 2 :0.9mL.

[0016] Furthermore, the hydrothermal reaction temperature is 180° C.-220° C., and the time is 15 h-25 h.

[0017] Furthermore, the vacuum drying temperature is 60° C.-80° C., and the drying time is 4 h-6 h.

[0018] Furthermore, the external circuit includes a wire and an external resistor, and the connection method is: wires are drawn from the piezoelectric anode and cathode respectively, and connected to the two ends of the external resistor to form a loop. Furthermore, the resistance range of the external resistor is 10Ω-2000Ω; the flow rate of the exposed air is 0.8L min -1 -3.5L min -1 ; The temperature of the pollutant solution to be treated is 20℃-30℃;

[0019] Furthermore, the cathode material is a conductive substrate, such as carbon fiber cloth. The cathode material may also be a piezoelectric catalytic cathode or an electrocatalytic cathode in which a piezoelectric catalyst or an electrocatalyst is loaded on a conductive substrate.

[0020] By using the above method, sulfur ions, difficult-to-degrade organic pollutants, or sterilization can be efficiently removed from water through aeration coupled with the piezoelectric effect.

[0021] Beneficial effects of the present invention: This invention provides a method for constructing and applying a piezoelectric catalytic fuel cell system. Under normal temperature and pressure, aeration alone can trigger the piezoelectric effect and redox reaction, enhancing oxygen-oxidative desulfurization and realizing wastewater resource utilization. The system is simple to operate, operates under mild and safe reaction conditions, and consumes low energy. Compared with biological methods, it is less susceptible to environmental factors and has a faster reaction rate, demonstrating practical application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram showing the effect of Fe@MoS2 / CFC||CFC system removing sulfur ions after reacting for 1.5 hours under air exposure conditions.

[0023] Figure 2 This is a diagram showing the effect of the CFC||CFC system removing sulfide ions after reacting for 1.5 hours under air exposure conditions.

[0024] Figure 3 This is a diagram showing the effect of Fe@MoS2 / CFC||CFC system removing sulfur ions after reacting for 1.5 hours under argon aeration conditions. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention is described in detail below in conjunction with the technical solutions and drawings.

[0026] Example 1: Preparation of catalytic electrodes and construction of piezoelectric catalytic fuel cells and their coupling systems

[0027] Step 1: Preparation of catalytic electrode:

[0028] (1) Cut 6×10cm 2 The carbon fiber cloth was soaked in anhydrous ethanol for 24 h and then repeatedly rinsed with deionized water to remove surface impurities. The cloth was placed in a vacuum drying oven and dried at 60°C for 6 h to obtain a clean carbon fiber cloth for use.

[0029] (2) Dissolve 1.2 g of Na₂MoO₄·2H₂O and 0.76 g of CH₄N₂S in 500 mL of deionized water and stir for 30 min to obtain a seed solution. Soak a clean carbon fiber cloth in the seed solution for 1 h, remove it, and dry it in a vacuum drying oven at 60°C for 6 h to obtain a pretreated carbon fiber cloth.

[0030] (3) Add 0.56g FeSO4·xH2O, 1.36g Na2MoO4·2H2O and 1.06g CH4N2S to 60mL deionized water respectively and stir for 30min to obtain a precursor solution. Place the pretreated carbon fiber cloth close to the inner wall of the reactor, pour the precursor solution into it, and place it in the reactor for hydrothermal reaction at 200℃ for 20h. After the reaction is completed, cool the reactor naturally to room temperature, take out the Fe@MoS2 loaded carbon fiber cloth, rinse it repeatedly with deionized water, place it in a vacuum drying oven at 60℃ and dry it for 6h, and then cut it into 3×3cm 2 , and Fe@MoS2 / CFC piezoelectric catalytic electrode was obtained. The CFC cathode was made of a 3×3cm 2 The clean carbon fiber cloth obtained by the method of step (1).

[0031] Step 2: Construction of piezoelectric catalytic fuel cell and its coupling system: Select a cylindrical glass reactor with a volume of 100 mL. Place Fe@MoS2 / CFC as the piezoelectric catalytic electrode and CFC as the counter electrode into the reactor, connect them with a wire and a 300Ω external resistor, and use S 2- The concentration is 180 mg L -1 Sodium sulfide (Na2S·9H2O) solution was used as the electrolyte, 90 mL was poured into the reactor, and the aeration head was inserted into the bottom of the reactor. The aeration rate was 3 L min -1 , as a provider of dissolved oxygen and mechanical force. The reaction was carried out at 25°C for 1.5 hours. After the reaction started, samples were taken every 15 minutes and the S content in the solution was determined by methylene blue spectrophotometry. 2- The concentration of S in the system is calculated. 2- concentration changes and removal efficiency.

[0032] like Figure 1The Fe@MoS2 / CFC||CFC piezoelectric catalytic fuel cell system reacts for 1.5h to S under aeration conditions. 2- As shown in the figure, after 1.5h of reaction, the system has a strong effect on S 2- The removal efficiency was 91% and the removal rate was 10.05 mg h -1 This indicates that the piezoelectric catalytic fuel cell coupled aeration system can effectively remove S from the solution. 2- .

[0033] Comparative Example 1: CFC || CFC oxidizes S under aeration conditions 2-

[0034] The system construction method is the same as that of Example 1, except that the piezoelectric catalytic electrode is replaced by a CFC electrode.

[0035] like Figure 2 The CFC||CFC system reacts for 1.5h under aeration conditions to S 2- As shown in the figure, after 1.5h of reaction, the system has a strong effect on S 2- The removal efficiency was 34% and the removal rate was 3.87 mg h -1 Compared with Example 2, it is shown that the piezoelectric catalytic activity of the Fe@MoS2 / CFC electrode has a positive effect on removing sulfides from water and improves the desulfurization capacity.

[0036] Comparative Example 2: Fe@MoS2 / CFC||CFC oxidizes S under argon atmosphere 2-

[0037] The method for constructing the piezoelectric catalytic fuel cell is the same as that in Example 1, except that the air exposed to the system is replaced with argon gas with the same flow rate.

[0038] like Figure 3 Fe@MoS2 / CFC||CFC reacts with S under argon atmosphere for 1.5h. 2- As shown in the figure, after 1.5h of reaction, the system has a strong effect on S 2- The removal efficiency was 24% and the removal rate was 2.66 mg h -1 Compared with Example 1, it shows that oxygen is more effective in removing S from water. 2- The catalytic electrode plays an important role. It has the best desulfurization effect when it is coupled with air exposure.

[0039] Example 2: Construction of a piezoelectric catalytic fuel cell and its coupling system

[0040] The catalytic electrode preparation method and sulfur ion testing method are the same as those in Example 1. However, in the construction of the piezoelectric catalytic fuel cell and its coupling system: In this example, a cylindrical insulating material reactor with a volume of 100mL is selected. Fe@MoS2 / CFC is the piezoelectric catalytic electrode, and CFC is the counter electrode. The reactor is placed and connected with a wire and a 10Ω external resistor. 2- The concentration is 200mgL -1 Sodium sulfide (Na2S·9H2O) solution was used as the electrolyte, 90 mL was poured into the reactor, and the aeration head was inserted into the bottom of the reactor. The aeration rate was 3.5 L min -1 , as a provider of dissolved oxygen and mechanical force. At 20℃, the reaction was carried out for 1.5h.

[0041] Example 3: Construction of a piezoelectric catalytic fuel cell and its coupling system

[0042] The catalytic electrode preparation method and sulfur ion testing method are the same as those in Example 1. However, in the construction of the piezoelectric catalytic fuel cell and its coupling system: In this example, a cylindrical insulating material reactor with a volume of 100mL is selected. Fe@MoS2 / CFC is the piezoelectric catalytic electrode, and CFC is the counter electrode. The reactor is placed and connected with a wire and a 2000Ω external resistor. 2- The concentration is 150mgL -1 Sodium sulfide (Na2S·9H2O) solution was used as the electrolyte, 90 mL was poured into the reactor, and the aeration head was inserted into the bottom of the reactor. The aeration rate was 0.8 L min -1 , as a provider of dissolved oxygen and mechanical force. The reaction was carried out at 30°C for 1.5 hours.

[0043] Example 4: Preparation of catalytic electrodes and construction of piezoelectric catalytic fuel cells and their coupling systems

[0044] Step 1: Preparation of catalytic electrode:

[0045] (1) Cut 5×9cm 2 The carbon fiber cloth was soaked in anhydrous ethanol for 8 h and then repeatedly rinsed with deionized water to remove surface impurities. The cloth was placed in a vacuum drying oven and dried at 80°C for 4 h to obtain a clean carbon fiber cloth for use.

[0046] (2) Dissolve 1.2 g of Na₂MoO₄·2H₂O and 0.76 g of CH₄N₂S in 500 mL of deionized water and stir for 30 min to obtain a seed solution. Soak a clean carbon fiber cloth in the seed solution for 1.5 h, remove it, and dry it in a vacuum drying oven at 80°C for 4 h to obtain a pretreated carbon fiber cloth.

[0047] (3) Add 0.56g FeSO4·xH2O, 1.36g Na2MoO4·2H2O and 1.06g CH4N2S to 60mL deionized water respectively and stir for 30min to obtain a precursor solution. Place the pretreated carbon fiber cloth close to the inner wall of the reactor, pour the precursor solution into it, and place it in the reactor for hydrothermal reaction at 200℃ for 20h. After the reaction is completed, cool the reactor naturally to room temperature, take out the carbon fiber cloth loaded with Fe@MoS2, rinse it repeatedly with deionized water, place it in a vacuum drying oven at 80℃ and dry it for 4h, and then cut it into 3×3cm 2 , and Fe@MoS2 / CFC piezoelectric catalytic electrode was obtained. The CFC cathode was made of a 3×3cm 2 The clean carbon fiber cloth obtained by the method of step (1).

[0048] Step 2: The construction method of the piezoelectric catalytic fuel cell and the sulfur ion testing method are the same as those in Example 1.

Claims

1. A method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation, characterized in that: Here are the steps: The piezoelectric anode and cathode are connected through an external circuit and placed in an insulating material reactor, with the pollutant solution to be treated serving as the electrolyte. An aeration head is inserted into the bottom of the reactor to provide dissolved oxygen and mechanical force. The reaction begins when the aeration pump is turned on. The power generation and sulfur ion removal effects are adjusted by adjusting the aeration intensity, the temperature of the pollutant solution to be treated, and the external resistance of the external circuit. The preparation steps of the piezoelectric anode are as follows: The clean carbon fiber cloth (CFC) after impurities removal with anhydrous ethanol was immersed in a seed solution containing Na2MoO4·2H2O and CH4N2S, and then dried in a vacuum drying oven after soaking for a period of time to obtain a seed layer CFC; FeSO4·xH2O, Na2MoO4·2H2O and CH4N2S were added to deionized water, stirred evenly, and the mixed solution was poured into a reactor; the seed layer CFC was placed in the reactor containing the mixed solution for a hydrothermal reaction; after the reaction was completed, the reactor was naturally cooled to room temperature, the Fe@MoS2-loaded CFC was taken out, repeatedly rinsed with deionized water, and fully dried in a vacuum drying oven to obtain a Fe@MoS2 / CFC piezoelectric catalytic electrode.

2. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: The molar concentration of S in the seed solution is 0.01 M - 0.03 M, which is 2 - 3 times that of Mo; the clean CFC is immersed in the seed solution for 0.5 h - 2 h.

3. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: In a mixed solution of FeSO4•xH2O, Na2MoO4•2H2O and CH4N2S, the molar concentration ratio of Fe and Mo is less than or equal to 1:1, and the molar concentration of S is 0.15 M - 0.25 M, which is 2-3 times the sum of the molar concentrations of Fe and Mo.

4. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: The addition ratio of seed layer CFC to mixed solution is 1 cm 2 :70 mL - 1 cm 2 :0.9 mL.

5. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: The hydrothermal reaction temperature is 180℃ - 220℃, and the time is 15 h - 25 h.

6. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: The vacuum drying temperature is 60℃ - 80℃, and the drying time is 4 h - 6 h.

7. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: The external circuit includes wires and an external resistor. The connection method is: wires are drawn from the piezoelectric anode and cathode respectively, and connected to the two ends of the external resistor to form a loop; the resistance range of the external resistor is 10 Ω - 2000 Ω; the flow rate of the exposed air is 0.8 L / min -1 - 3.5 L min -1 ; The temperature of the pollutant solution to be treated is 20℃ - 30℃.

8. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: The material of the cathode is a conductive substrate, or a piezoelectric catalytic cathode or an electrocatalytic cathode in which a piezoelectric catalyst or an electrocatalyst is loaded on a conductive substrate.

9. The method for removing sulfur ions from water by coupling a piezoelectric catalytic fuel cell with oxygen oxidation according to claim 1, characterized in that: Through aeration coupled with the piezoelectric effect, sulfur ions in water can be efficiently removed, while difficult-to-degrade organic pollutants can be removed or sterilized.

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