Nickel titanium black electrode for removing PFOS (perfluorooctane sulfonate) as well as preparation method and application of nickel titanium black electrode

Abstract

The invention relates to the technical field of water treatment and environmental treatment, in particular to a nickel titanium black electrode for removing PFOS (perfluorooctane sulfonate) as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing an aluminum oxide template in an anodic oxidation manner; mixing a titanium source and a nickel source, and standing to obtain sol; combining the aluminum oxide template with a titanium mesh to obtain a substrate, coating the sol on the surface of the substrate, and drying to obtain a nickel titanium black film / substrate composition; and under a protective atmosphere, pre-sintering and calcining the nickel titanium black film / substrate composition to obtain a calcined product, placing the calcined product in an alkaline solution, standing and washing to obtain the PFOS-removed nickel titanium black electrode. The nickel titanium black electrode prepared by the invention has lower internal resistance and larger electrochemical active area, and can efficiently remove perfluorooctane sulfonic acid pollution in water. In the application of water treatment, excellent removal effect, stability and long service life are shown.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment and environmental governance, in particular to a nickel sub-titanium oxide electrode for removing PFOS and a preparation method and application thereof. BACKGROUND

[0002] As a kind of persistent organic pollutants, perfluorooctane sulfonate (PFOS) is widely used in industrial production, fire-fighting foam and daily consumer goods. Due to its strong hydrophobicity and chemical properties of high temperature resistance, acid and alkali resistance, perfluorooctane sulfonate is difficult to degrade in the environment and easy to accumulate, which poses a potential threat to aquatic organisms and human health. In recent years, perfluorooctane sulfonate pollution has become one of the main problems of global water pollution. Due to the strong bioaccumulation and long-term existence of perfluorooctane sulfonate, the existing traditional removal technologies such as adsorption, chemical degradation and biodegradation, although can reduce the concentration of perfluorooctane sulfonate to some extent, due to low removal efficiency, long treatment time and secondary pollution problems, have not yet effectively solved the problem of perfluorooctane sulfonate pollution.

[0003] For the efficient removal of perfluorooctane sulfonate, electrochemical catalytic degradation technology has attracted widespread attention due to its fast reaction rate, simple operation and low energy consumption. In the process of electrochemical degradation, the selection of electrode material is a key factor, and suitable electrode material not only can improve the degradation efficiency, but also can reduce the loss and pollution of catalyst. In recent years, nickel sub-titanium oxide electrode has become a new electrode material for removing perfluorooctane sulfonate due to its excellent electrochemical performance, stability and low cost. Although some studies have explored the application of different electrode materials in the degradation of perfluorooctane sulfonate, how to improve the catalytic activity, stability and long-term performance of nickel sub-titanium oxide electrode is still a challenge for current technology. Therefore, it is of important academic value and application prospect to develop an efficient and stable nickel sub-titanium oxide electrode for removing perfluorooctane sulfonate. SUMMARY

[0004] The purpose of the present application is to provide a nickel sub-titanium oxide electrode for removing PFOS and a preparation method and application thereof, in order to solve the problems of low efficiency and short service life of existing nickel sub-titanium oxide electrode in the process of removing perfluorooctane sulfonate.

[0005] To achieve the above-mentioned purpose, the present application provides a preparation method of a nickel sub-titanium oxide electrode for removing PFOS, comprising the following preparation steps: S1, preparing an aluminum oxide template by anodic oxidation; S2, mixing a titanium source and a nickel source, and standing to obtain a sol; S3, combining the aluminum oxide template with a titanium mesh to obtain a substrate, and coating the sol on the surface of the substrate and drying to obtain a nickel sub-titanium oxide film / substrate composition; S4, pre-sintering, calcining the nickel titanate sub-oxide film / substrate composition under a protective atmosphere to obtain a calcined product, placing the calcined product in an alkaline solution, standing, washing to obtain a nickel titanate sub-oxide electrode from which PFOS is removed.

[0006] In the present application, the process of anodic oxidation in S1 comprises: In the present application, the process of anodic oxidation in S1 comprises:

[0007] In the present application, the acid solution comprises at least one of oxalic acid solution, formic acid solution, acetic acid solution, the concentration of the acid solution is 0.1-0.5 mol / L, the voltage of anodic oxidation is 40-60 V, and the time of anodic oxidation is 1-2 h.

[0008] In the present application, the alkaline solution comprises at least one of sodium hydroxide solution and potassium hydroxide solution, the mass concentration of the alkaline solution is 1wt%-5wt%, the temperature of alkaline treatment is 60-80℃, and the time of alkaline treatment is 10-30 min.

[0009] In the present application, after the process of anodic oxidation to obtain the oxidation product, the oxidation product is placed in an alkaline solution for alkaline treatment, and the purpose of alkaline treatment is to remove the aluminum sheet to obtain a self-supporting aluminum oxide template.

[0010] In the present application, the titanium source in S2 comprises at least one of tetrabutyl titanate, tetraethyl titanate, and tetraisopropyl titanate, the nickel source comprises at least one of nickel acetate, nickel nitrate, and nickel sulfate, the mass ratio of the titanium source and the nickel source is 1:1-3, the temperature of standing is 18-25℃, and the time of standing is 12-24 h.

[0011] In the present application, the purpose of standing in S2 is to promote further aging and stabilization of the sol.

[0012] In the present application, after the process of S3 of applying the sol to the surface of the substrate, the thickness of the sol on the surface of the substrate is 0.3-0.5 mm; the temperature of drying in S3 is 45-60℃, and the time of drying is 12-24 h.

[0013] In the present application, the protective atmosphere in S4 comprises argon or nitrogen.

[0014] In the present application, the temperature of pre-sintering in S4 is 100-150℃, the time of pre-sintering is 10-30 min, the heating rate of calcining is 2-2.5℃ / min, the temperature of calcining is 500-550℃, and the time of calcining is 1-2 h.

[0015] In the present application, the purpose of placing the calcined product in an alkaline solution in S4 is to remove the aluminum oxide template.

[0016] In the present application, the basic solution in S4 includes at least one of sodium hydroxide solution and potassium hydroxide solution, the concentration of the basic solution is 3-5 mol / L, the temperature of the standing is 60-80 DEG C, and the time of the standing is 10-30 min.

[0017] The present application also provides a preparation method of the nickel sub-titanium oxide electrode for removing PFOS.

[0018] The present application also provides an application of the nickel sub-titanium oxide electrode for removing PFOS in degrading perfluorooctane sulfonic acid.

[0019] The present application has the following beneficial effects: The present application provides a preparation method of the nickel sub-titanium oxide electrode for removing PFOS, which comprises the following preparation steps: S1, preparing an alumina template by an anodic oxidation method; S2, mixing a titanium source and a nickel source, standing to obtain a sol; S3, combining the alumina template with a titanium mesh to obtain a substrate, coating the sol on the surface of the substrate, drying to obtain a nickel sub-titanium oxide film / substrate composition; S4, pre-sintering and calcining the nickel sub-titanium oxide film / substrate composition under a protective atmosphere to obtain a calcined product, placing the calcined product in a basic solution, standing, washing to obtain the nickel sub-titanium oxide electrode for removing PFOS.

[0020] The present application adopts the anodic oxidation method to prepare the alumina template, and the obtained alumina template has a porous structure, and in the subsequent sol coating process, the sol penetrates the pores of the alumina template and is attached to the titanium mesh. After the alumina template is removed through the step S4 calcination and basic solution treatment, a porous structure corresponding to the alumina template is finally formed on the surface of the titanium mesh, and the electrochemical active area and active sites are increased.

[0021] The present application makes the nickel sub-titanium oxide film and the substrate tightly combined through the calcination process, and a stable nickel sub-titanium oxide structure is formed in the calcination process, the electron migration resistance is reduced, and the electrochemical active area is increased. At the same time, the acid and alkali stability of the nickel sub-titanium oxide electrode is also enhanced, so that it can be applied in various pH environments.

[0022] The preparation method provided by the present application is simple and low in cost, and is suitable for water treatment equipment of different scales, and has a wide application prospect, especially in the fields of industrial wastewater and drinking water treatment.

[0023] The nickel sub-titanium oxide electrode for removing PFOS prepared by the preparation method has a low internal resistance, and the internal resistance is only 10-20 Ω. The electrochemical active area is large, and reaches 78.8 cm 2, which improves the electron transport efficiency and the number of catalytic active sites, further improves the perfluorooctane sulfonate removal efficiency. It has a wide pH activation range, and can maintain perfluorooctane sulfonate removal efficiency above 90% in the pH range of 3.5-11.0, and can be applied to a wide range of applications. At the same time, it can maintain a removal efficiency of more than 90% after being used repeatedly for 10 times, and has excellent stability and long service life.

[0024] The technical solutions of the present application are further described below with the aid of the accompanying drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is the internal resistance test result graph of the PFOS removal nickel titanium sub-oxide electrode prepared in the present application examples 1-3; Figure 2 is the internal resistance test result graph of the Ni electrode prepared in the present application comparative example 1 and the Ti4O7 electrode prepared in the present application comparative example 2; Figure 3 is the electrochemical active area test result graph of the PFOS removal nickel titanium sub-oxide electrode prepared in the present application examples 1-3; Figure 4 is the electrochemical active area test result graph of the Ni electrode prepared in the present application comparative example 1 and the Ti4O7 electrode prepared in the present application comparative example 2; Figure 5 is the degradation efficiency test graph of perfluorooctane sulfonate by the PFOS removal nickel titanium sub-oxide electrode prepared in the present application examples 1-3; Figure 6 is the degradation efficiency test graph of perfluorooctane sulfonate by the Ni electrode prepared in the present application comparative example 1 and the Ti4O7 electrode prepared in the present application comparative example 2; Figure 7 is the removal efficiency result graph of perfluorooctane sulfonate by the PFOS removal nickel titanium sub-oxide electrode prepared in example 2 under different pH ranges; Figure 8 is the removal efficiency result graph of perfluorooctane sulfonate by the PFOS removal nickel titanium sub-oxide electrode prepared in example 2 during multiple cycles. DETAILED DESCRIPTION

[0026] The present application is further described below in conjunction with the accompanying drawings and examples. Unless otherwise defined, the technical terms or scientific terms used in the present application shall be understood as the usual meaning understood by those skilled in the art to which the present application belongs. The features mentioned above or the features mentioned in the specific examples can be combined arbitrarily, and these specific examples are only used to illustrate the present application and not to limit the scope of the present application.

[0027] Example 1 A preparation method of a nickel sub-titanium oxide electrode for removing PFOS, comprising the following preparation steps: S1, taking aluminum sheet as anode, graphite as cathode, 0.5 mol / L oxalic acid solution as electrolyte of battery system, anodizing at 40 V for 1.5 h to obtain an oxidation product, and placing the oxidation product in a 2 wt% sodium hydroxide solution for alkaline treatment at 80°C for 20 min to obtain an aluminum oxide template; S2, mixing tetrabutyl titanate and nickel acetate at a mass ratio of 1:1, and then standing at 25°C for 18 h to obtain a sol; S3, combining the aluminum oxide template with a titanium mesh to obtain a substrate, and coating the sol on the surface of the substrate, wherein the thickness of the sol on the surface of the substrate is 0.3 mm, and then placing it in a vacuum drying box for drying at 50°C for 12 h to obtain a nickel sub-titanium oxide film / substrate composition; S4, pre-sintering the nickel sub-titanium oxide film / substrate composition at 125°C for 30 min under a nitrogen atmosphere, and then heating to 550°C at a heating rate of 2°C / min, and calcining for 2 h to obtain a calcined product, and placing the calcined product in a 3 mol / L sodium hydroxide solution and standing at 60°C for 30 min, and then washing to obtain a nickel sub-titanium oxide electrode for removing PFOS, denoted as Ni / Ti4O7-1 electrode.

[0028] Example 2 A preparation method of a nickel sub-titanium oxide electrode for removing PFOS, comprising the following preparation steps: S1, taking aluminum sheet as anode, graphite as cathode, 0.5 mol / L oxalic acid solution as electrolyte of battery system, anodizing at 40 V for 1.5 h to obtain an oxidation product, and placing the oxidation product in a 2 wt% sodium hydroxide solution for alkaline treatment at 80°C for 20 min to obtain an aluminum oxide template; S2, mixing tetrabutyl titanate and nickel acetate at a mass ratio of 1:2, and then standing at 25°C for 12 h to obtain a sol; S3, combining the aluminum oxide template with a titanium mesh to obtain a substrate, and coating the sol on the surface of the substrate, wherein the thickness of the sol on the surface of the substrate is 0.3 mm, and then placing it in a vacuum drying box for drying at 50°C for 12 h to obtain a nickel sub-titanium oxide film / substrate composition; S4, pre-sintering the nickel sub-titanium oxide film / substrate composition at a temperature of 100℃ for 10min under a nitrogen atmosphere, then heating to a temperature of 530℃ at a heating rate of 2.2℃ / min, calcining for 2h, obtaining a calcined product, placing the calcined product in a sodium hydroxide solution with a mass concentration of 3wt%, standing for 30min at a temperature of 60℃, washing, obtaining a nickel sub-titanium oxide electrode with PFOS removed, denoted as Ni / Ti4O7-3 electrode.

[0029] Example 3 A preparation method of a nickel sub-titanium oxide electrode with PFOS removed, comprising the following preparation steps: S1, anodizing an aluminum sheet as an anode, a graphite as a cathode, and a 0.1mol / L oxalic acid solution as an electrolyte at a voltage of 50V for 2h, obtaining an oxidation product, placing the oxidation product in a sodium hydroxide solution with a mass concentration of 1wt%, and alkaline treating at 70℃ for 30min, obtaining an aluminum oxide template; S2, mixing tetrabutyl titanate and nickel acetate according to a mass ratio of 1:3, and standing at a temperature of 25℃ for 24h, obtaining a sol; S3, combining the aluminum oxide template with a titanium mesh to obtain a substrate, and coating the sol on the surface of the substrate, the thickness of the sol on the surface of the substrate being 0.5mm, then placing it in a vacuum drying box and drying at a temperature of 60℃ for 18h, obtaining a nickel sub-titanium oxide film / substrate composition; S4, pre-sintering the nickel sub-titanium oxide film / substrate composition at a temperature of 100℃ for 10min under a nitrogen atmosphere, then heating to a temperature of 530℃ at a heating rate of 2.2℃ / min, calcining for 2h, obtaining a calcined product, placing the calcined product in a sodium hydroxide solution with a mass concentration of 3wt%, standing for 30min at a temperature of 60℃, washing, obtaining a nickel sub-titanium oxide electrode with PFOS removed, denoted as Ni / Ti4O7-3 electrode.

[0030] Comparative Example 1 A preparation method of a Ni electrode, comprising the following preparation steps: S1, anodizing an aluminum sheet as an anode, a graphite as a cathode, and a 0.1mol / L oxalic acid solution as an electrolyte at a voltage of 50V for 2h, obtaining an oxidation product, placing the oxidation product in a sodium hydroxide solution with a mass concentration of 1wt%, and alkaline treating at 70℃ for 30min, obtaining an aluminum oxide template; S2, combining the aluminum oxide template with a titanium mesh to obtain a substrate, then immersing the substrate in a mixed solution of nickel acetate / ethanol with a concentration of 1mol / L at a temperature of 80℃, taking it out, then placing it in a vacuum drying box and drying at a temperature of 45℃ for 24h, obtaining a nickel / substrate composition; S3, pre-sintering the nickel / titanium suboxide substrate composition at a temperature of 150°C for 20 min under a nitrogen atmosphere, then heating to a temperature of 500°C at a heating rate of 2.5°C / min, calcining for 2 h to obtain a calcined product, placing the calcined product in a sodium hydroxide solution with a concentration of 3 mol / L, and standing at a temperature of 60°C for 30 min, and washing to obtain a Ni electrode.

[0031] Comparative Example 2 A method for preparing a Ti4O7 electrode, comprising the following preparation steps: S1, anodizing an aluminum sheet as an anode and a graphite as a cathode in an oxalic acid solution with a concentration of 0.3 mol / L at a voltage of 60 V for 1 h to obtain an oxidation product, placing the oxidation product in a sodium hydroxide solution with a mass concentration of 5 wt%, and alkaline treating at 60°C for 10 min to obtain an aluminum oxide template; S2, combining the aluminum oxide template with a titanium mesh to obtain a substrate, and coating tetrabutyl titanate on the surface of the substrate, the thickness of the tetrabutyl titanate on the surface of the substrate being 0.4 mm, and then placing it in a vacuum drying oven and drying at a temperature of 45°C for 24 h to obtain a titanium suboxide / substrate composition; S3, pre-sintering the titanium suboxide / substrate composition at a temperature of 150°C for 20 min under a nitrogen atmosphere, then heating to a temperature of 500°C at a heating rate of 2.5°C / min, calcining for 2 h to obtain a calcined product, placing the calcined product in a sodium hydroxide solution with a concentration of 3 mol / L, and standing at a temperature of 60°C for 30 min, and washing to obtain a Ti4O7 electrode.

[0032] Performance test: The internal resistance of the PFOS removal nickel titanium suboxide electrodes prepared in Examples 1-3 was tested, and the results are shown in Table 1. Figure 1 As can be seen from Table 1, the internal resistance of the Ni / Ti4O7-1 electrode prepared in Example 1 was 17.2Ω, the internal resistance of the Ni / Ti4O7-2 electrode prepared in Example 2 was 16.6Ω, and the internal resistance of the Ni / Ti4O7-3 electrode prepared in Example 3 was 16.9Ω. Figure 1 The internal resistance of the Ni electrode prepared in Comparative Example 1 and the Ti4O7 electrode prepared in Comparative Example 2 was tested, and the results are shown in Table 2.

[0033] As can be seen from Table 2, the internal resistance of the Ni electrode prepared in Comparative Example 1 was 36.4Ω, and the internal resistance of the Ti4O7 electrode prepared in Comparative Example 2 was 33.1Ω. Figure 2 Figure 2 The electrochemical active area of the PFOS removal nickel titanium suboxide electrodes prepared in Examples 1-3 was tested, and the results are shown in Table 3. As can be seen from Table 3, the electrochemical active area of the Ni / Ti4O7-1 electrode prepared in Example 1 was 0.22 cm2, the electrochemical active area of the Ni / Ti4O7-2 electrode prepared in Example 2 was 0.21 cm2, and the electrochemical active area of the Ni / Ti4O7-3 electrode prepared in Example 3 was 0.22 cm2.

[0034] Figure 3 The electrochemical active area of the Ni electrode prepared in Comparative Example 1 and the Ti4O7 electrode prepared in Comparative Example 2 was tested, and the results are shown in Table 4. Figure 3 ​It can be seen that the electrochemically active area of ​​the Ni / Ti4O7-1 electrode prepared in Example 1 is 76.3 cm². 2 The Ni / Ti4O7-2 electrode prepared in Example 2 has an electrochemical active area of ​​78.8 cm². 2 The Ni / Ti4O7-3 electrode prepared in Example 3 has an electrochemical active area of ​​75.4 cm². 2 .

[0035] The electrochemical active areas of the Ni electrode prepared in Comparative Example 1 and the Ti4O7 electrode prepared in Comparative Example 2 were tested, and the results are as follows: Figure 4 As shown. From Figure 4 It can be seen that the electrochemically active area of ​​the Ni electrode prepared in Comparative Example 1 is 31.5 cm². 2 The electrochemically active area of ​​the Ti4O7 electrode prepared in Comparative Example 2 was 45.6 cm². 2 .

[0036] The degradation efficiency of perfluorooctane sulfonic acid by the PFOS-removed nickel titanium suboxide electrodes prepared in Examples 1-3 was tested. The nickel-titanium suboxide electrodes prepared in Examples 1-3 for PFOS removal were used as anodes, and titanium sheet electrodes as cathodes, respectively, and placed in 300 mL of a mixed solution (containing perfluorooctane sulfonic acid, potassium persulfate, and water). The concentration of perfluorooctane sulfonic acid in the mixed solution was 5 mg / L, and the concentration of potassium persulfate was 0.5 mmol / L. The experimental temperature was 25 °C, and the pH of the solution was 5.0. The current density was 10 mA / cm². 2 At that time, the degradation effect of perfluorooctane sulfonic acid was as follows: Figure 5 As shown. From Figure 5 It can be seen that within 20 minutes, the degradation efficiency of perfluorooctane sulfonic acid by the Ni / Ti4O7-1 electrode in Example 1 reached 97.5%, the degradation efficiency of perfluorooctane sulfonic acid by the Ni / Ti4O7-2 electrode in Example 2 reached 100%, and the degradation efficiency of perfluorooctane sulfonic acid by the Ni / Ti4O7-3 electrode in Example 3 reached 98.9%.

[0037] The degradation efficiency of perfluorooctane sulfonic acid by the Ni electrode prepared in Comparative Example 1 and the Ti4O7 electrode prepared in Comparative Example 2 was tested: The Ni electrode prepared in Comparative Example 1 and the Ti4O7 electrode prepared in Comparative Example 2 were used as anodes, and the titanium sheet electrode was used as cathode. Both electrodes were placed in 300 mL of a mixed solution (containing perfluorooctane sulfonic acid, potassium persulfate, and water). The concentration of perfluorooctane sulfonic acid in the mixed solution was 5 mg / L, and the concentration of potassium persulfate was 0.5 mmol / L. The experimental temperature was 25 °C, and the pH of the solution was 5.0. The current density was 10 mA / cm². 2 At that time, the degradation effect of perfluorooctane sulfonic acid was as follows:Figure 6 As shown. From Figure 6 It can be seen that within 20 minutes, the degradation rate of perfluorooctane sulfonic acid by the Ni electrode in Comparative Example 1 was 11.1%, and the degradation rate of perfluorooctane sulfonic acid by the Ti4O7 electrode in Comparative Example 2 was 53.6%, both significantly lower than those in the Example.

[0038] The degradation efficiency of perfluorooctane sulfonic acid by the PFOS-removed nickel titanium suboxide electrode prepared in Example 2 was tested at different pH values: The PFOS-removed nickel-titanium oxide electrode prepared in Example 2 was used as the anode, and the titanium sheet electrode as the cathode, placed in 300 mL of a mixed solution (the mixed solution included perfluorooctane sulfonic acid, potassium persulfate, and water). In the mixed solution, the concentration of perfluorooctane sulfonic acid was 5 mg / L, and the concentration of potassium persulfate was 0.5 mmol / L. The experimental temperature was 25 °C, and the current density was 10 mA / cm². 2 The pH of the solution was adjusted to 3.5, 5.5, 7.0, 9.0, and 11.0, and the removal efficiency of perfluorooctane sulfonic acid was tested at different pH values. The results are as follows: Figure 7 As shown.

[0039] from Figure 7 As can be seen, the nickel titanium suboxide electrode for removing PFOS prepared in Example 2 has a removal efficiency of 98.2%-100% for perfluorooctane sulfonic acid over a wide pH range (3.5-11.0), which confirms that the nickel titanium suboxide electrode for removing PFOS prepared in this invention has a wide pH range and high efficiency in removing perfluorooctane sulfonic acid.

[0040] The degradation efficiency of perfluorooctane sulfonic acid by the PFOS-removed nickel titanium suboxide electrode prepared in Example 2 was tested after multiple cycles: The nickel-titanium suboxide electrode with PFOS removal prepared in Example 2 was used as the anode, and the titanium sheet electrode as the cathode, placed in 300 mL of a mixed solution (the mixed solution included perfluorooctane sulfonic acid, potassium persulfate, and water). In the mixed solution, the concentration of perfluorooctane sulfonic acid was 5 mg / L, and the concentration of potassium persulfate was 0.5 mmol / L. The experimental temperature was 25 °C, and the pH of the solution was 5.0. The current density was 10 mA / cm². 2 At that time, degradation was carried out for 20 minutes, with 10 cycles. After each degradation cycle, the mixed solution was replaced. The results are as follows. Figure 8 As shown. From Figure 8 It can be seen that after 10 cycles, the degradation rate of perfluorooctane sulfonic acid is still as high as 99.0%, which confirms that the nickel titanium suboxide electrode with PFOS removal prepared in this invention has good reusability.

[0041] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for producing a nickel sub-titanium electrode for removing PFOS, characterized by, The preparation method comprises the following steps: S1, preparing an aluminum oxide template by anodic oxidation; S2, mixing a titanium source and a nickel source, and standing to obtain a sol; S3, combining the aluminum oxide template with a titanium mesh to obtain a substrate, coating the sol on the surface of the substrate, and drying to obtain a nickel sub-titanium oxide film / substrate composition; S4, pre-sintering and calcining the nickel sub-titanium oxide film / substrate composition under a protective atmosphere to obtain a calcined product, placing the calcined product in an alkaline solution, standing, and washing to obtain a nickel sub-titanium oxide electrode for removing PFOS.

2. The method for preparing a nickel sub-titanium oxide electrode for removing PFOS according to claim 1, characterized in that, The process of anodic oxidation in S1 comprises: An anodic oxidation is performed in a battery system with an aluminum sheet as an anode, graphite as a cathode, and an acid solution as an electrolyte, and then the oxidation product is placed in an alkaline solution for alkaline treatment to obtain the aluminum oxide template.

3. The method for preparing a nickel titanium suboxide electrode with PFOS removal according to claim 2, characterized in that, The acid solution comprises at least one of oxalic acid solution, formic acid solution and acetic acid solution, the concentration of the acid solution is 0.1-0.5 mol / L, the voltage of anodic oxidation is 40-60 V, and the time of anodic oxidation is 1-2 h.

4. The method for preparing a nickel titanium suboxide electrode with PFOS removal according to claim 2, characterized in that, The alkaline solution comprises at least one of sodium hydroxide solution and potassium hydroxide solution, the mass concentration of the alkaline solution is 1wt%-5wt%, the temperature of alkaline treatment is 60-80℃, and the time of alkaline treatment is 10-30 min.

5. The method for preparing a nickel titanium suboxide electrode with PFOS removal according to claim 1, characterized in that, The titanium source in S2 comprises at least one of tetrabutyl titanate, tetraethyl titanate and tetraisopropyl titanate, the nickel source comprises at least one of nickel acetate, nickel nitrate and nickel sulfate, the mass ratio of the titanium source and the nickel source is 1:1-3, the standing temperature is 18-25℃, and the standing time is 12-24 h.

6. The method for preparing a nickel titanium suboxide electrode with PFOS removal according to claim 1, characterized in that, After the sol is coated on the surface of the substrate in S3, the thickness of the sol on the surface of the substrate is 0.3-0.5 mm; The drying temperature in S3 is 45-60℃, and the drying time is 12-24 h.

7. The method for preparing a nickel titanium suboxide electrode with PFOS removal according to claim 1, characterized in that, The pre-sintering temperature in S4 is 100-150℃, the pre-sintering time is 10-30 min, the heating rate of calcination is 2-2.5℃ / min, the calcination temperature is 500-550℃, and the calcination time is 1-2 h.

8. The method for preparing a nickel titanium suboxide electrode with PFOS removal according to claim 1, characterized in that, The alkaline solution in S4 comprises at least one of sodium hydroxide solution and potassium hydroxide solution, the concentration of the alkaline solution is 3-5 mol / L, the standing temperature is 60-80℃, and the standing time is 10-30 min.

9. A nickel sub-titanium oxide electrode for removing PFOS prepared by the preparation method of the nickel sub-titanium oxide electrode for removing PFOS according to any one of claims 1-8.

10. The application of the nickel sub-titanium oxide electrode for removing PFOS according to claim 9 in degrading perfluorooctane sulfonic acid.

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