Catalyst as well as preparation method and application thereof

Abstract

The invention relates to a catalyst and a preparation method and application thereof, and belongs to the technical field of water treatment. The method comprises the following steps: dissolving a tin source and a tantalum source in a solvent to obtain a mixed solution; soaking a template with pores in the mixed solution to obtain an intermediate; carrying out a heating reaction on the intermediate to obtain a catalyst; the tantalum-doped tin-containing electrode catalyst is prepared by adopting a tin source and a tantalum source, and the tantalum-doped tin-containing electrode catalyst has relatively good activity and stability. And meanwhile, compared with an electrode prepared by a noble metal catalyst, the preparation cost is relatively low. Compared with an electrode prepared from a lead-containing catalyst, Sn and Ta used by the electrode have lower toxicity to water and human bodies.

Description

Technical Field

[0001] This application relates to the technical field of water treatment, and particularly to a catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] At present, most oil fields in China have entered the tertiary oil recovery stage. The water content in the produced fluid is 70%-80%, and in some oil fields, it has even reached as high as 90%. The amount of produced water is very large. Polymer flooding and ASP flooding are the most important tertiary oil recovery technologies and have been widely promoted in many oil fields.

[0003] The produced water from oil fields has a complex composition. It not only contains crude oil, but also dissolves various salts and gases in the formation under high temperature and high pressure, with a high salinity. During the oil production process, a lot of suspended solids are carried from the oil layer. During oil production, oil-gas gathering and transportation, and downhole operations, various chemical agents are added. The produced water from polymer flooding also contains a large amount of polymers (mainly polyacrylamide), and the concentration of polymers is generally 200-1000 mg / L. The presence of polymers increases the viscosity of the sewage, enhances the oil-carrying capacity of the water phase, and at the same time enhances the emulsification stability of particles such as oil droplets in the water, increasing the difficulty of oil-water separation and adding difficulty to the subsequent treatment of produced water. The treatment of produced water from polymer flooding has become the main limiting factor for the industrial promotion of polymer flooding and is an important issue that needs to be urgently solved in Chinese oil fields.

[0004] With the wide application of polymer flooding, a large amount of polymer-containing produced water has been generated. After the polymer-containing produced water is treated, depending on the water quality, the main destinations are reinjection, polymer blending, low-pressure steam boilers, and discharge up to the standard. The main treatment methods for produced water are: ① sedimentation separation - filtration to remove oil and suspended solids. The treatment methods for the oil removal section of sedimentation separation include gravity sedimentation, coagulation sedimentation, electrocoagulation, inclined plate sedimentation, pressure sedimentation, air flotation, and hydrocyclone methods, etc. Sometimes, several methods are combined; the treatment methods for the filtration section include walnut shell filtration, quartz sand filtration, fiber ball filtration, manganese sand filtration, membrane separation, etc.; ② chemical oxidation method to remove polymers, reducing substances, and bacteria in the produced water. Chemical oxidation methods include chemical reagent oxidation, air oxidation, photocatalytic oxidation, etc.; ② biochemical treatment process to remove organic matter and some inorganic substances in the produced water. The main biological treatment methods include anaerobic biological method, aerobic oxidation method, etc.

[0005] As a new type of difficult-to-treat oil field sewage, polymer-containing sewage must be treated before it can be discharged or reused. However, the existing oil field produced water treatment technology has significantly lagged behind and cannot keep up with the rapid development of the petroleum industry, becoming one of the key factors restricting the further development of the petroleum industry. Therefore, developing the best process suitable for the treatment of produced water in each oil field is an urgent problem to be solved currently.

[0006] Electrocatalytic oxidation is a green chemical technology that uses metal oxide electrodes with catalytic properties to generate hydroxyl radicals or other radicals and groups with strong oxidation ability to attack organic pollutants in the solution, completely decomposing them into harmless H2O and CO2. Due to its high oxidation efficiency for organic substances and some reducing substances, simple operation, high equipment integration, and small floor area, this method has shown high degradation ability, especially in the treatment of biologically refractory wastewater, and has gradually become a research hotspot in the field of water pollution control.

[0007] In electrochemical wastewater treatment, the selection of anode materials directly determines the efficiency of water treatment. There are various types of organic substances in oilfield produced water. There are many organic matter mineralization reactions involved in the electrochemical oxidation on the anode side, and the regulation mechanisms of side reactions such as chlorine evolution and hydrogen evolution are complex. The anode used for the electrochemical degradation of oilfield produced water coupled with hydrogen evolution reaction needs to meet the characteristics of being cheap, stable, and highly active. Commercial electrodes have a slow reaction rate, large overpotential, and poor stability in the electrochemical oxidation process of oilfield produced water. At the same time, although the currently commercial Ru-Ir electrodes and Pt-Pd electrodes have stable performance, they are expensive due to the use of precious metals. Although the BDD electrode only uses cheap metals such as boron and carbon, its preparation process uses chemical vapor deposition method, and the preparation cost remains high, making it difficult to be used on a large scale. Therefore, it is necessary to specifically develop anode materials suitable for the treatment of oilfield produced water. Summary of the Invention

[0008] This application provides a catalyst, its preparation method and application to improve the problem that the catalysts for the treatment of oilfield produced water are difficult to produce on a large scale at present.

[0009] In the first aspect, this application provides a preparation method of a catalyst, and the method includes:

[0010] Dissolve a tin source and a tantalum source in a solvent to obtain a mixed solution;

[0011] Immerse a template with pores in the mixed solution to obtain an intermediate;

[0012] Carry out a heating reaction on the intermediate to obtain a catalyst.

[0013] The above technical solutions provided by the embodiments of this application have the following advantages compared with the prior art:

[0014] The method provided by the embodiments of this application prepares a tantalum-doped tin-containing electrode catalyst by using a tin source and a tantalum source, which has good activity and stability. At the same time, compared with the electrodes prepared by precious metal catalysts, it has a lower preparation cost. Compared with the electrodes prepared by lead-containing catalysts, the Sn and Ta used in it have lower toxicity to water bodies and humans.

[0015] As an alternative embodiment, the tin source includes SnCl2·2H2O.

[0016] As an alternative embodiment, the tantalum source includes TaCl5.

[0017] As an alternative embodiment, the molar ratio of tin in the tin source to tantalum in the tantalum source is (1 - 10):1.

[0018] As an alternative embodiment, the molar ratio of tin in the tin source to tantalum in the tantalum source is (6 - 8):1.

[0019] As an alternative embodiment, the solvent includes absolute ethanol.

[0020] As an alternative embodiment, the relationship between the volume of the solvent and the total mass of the tin source and the tantalum source satisfies: 1 - 3 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution.

[0021] As an alternative embodiment, the relationship between the volume of the solvent and the total mass of the tin source and the tantalum source satisfies: 1.5 - 2.5 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution.

[0022] As an alternative embodiment, the template includes microspheres distributed in an array.

[0023] As an alternative embodiment, the material of the microspheres includes polymethyl methacrylate.

[0024] As an alternative embodiment, the particle size of the microspheres is 3 - 100 microns.

[0025] As an alternative embodiment, the particle size of the microspheres is 30 - 70 microns.

[0026] As an alternative embodiment, the infiltration time is 3 - 5 hours.

[0027] As an alternative embodiment, the infiltration time is 3.5 - 4.5 hours.

[0028] As an alternative embodiment, the heating rate of the heating reaction is 4 - 6 °C / min; and / or

[0029] the end temperature of the heating reaction is 500 - 600 °C; and / or

[0030] the holding time of the heating reaction is 2 - 4 hours.

[0031] As an alternative embodiment, the heating rate of the heating reaction is 4.5 - 5.5 °C / min; and / or

[0032] The end temperature of the heating reaction is 530 - 570 °C; and / or

[0033] The heat preservation time of the heating reaction is 2.5 - 3.5 hours.

[0034] In a second aspect, the present application provides a catalyst, which is prepared by using the catalyst preparation method described in the first aspect.

[0035] In a third aspect, the present application provides an electrode, which includes the catalyst described in the second aspect.

[0036] As an optional implementation manner, the loading amount of the catalyst in the electrode is 1 - 10 mg / cm².

[0037] In a fourth aspect, the present application provides an application of a catalyst, the catalyst includes the catalyst described in the second aspect; the application includes using the catalyst as an anode material for the electrochemical treatment of produced water in oilfields. Description of the Drawings

[0038] The drawings here are incorporated into the description and form a part of this description, showing embodiments consistent with the present application, and are used together with the description to explain the principles of the present application.

[0039] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a flowchart of the method provided by the embodiment of the present application;

[0041] Figure 2 It is an electron micrograph of the catalyst provided by Embodiment 3 of the present application. Detailed Embodiments

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0043] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments, and equipment used in the present application can be obtained through market purchase or can be prepared by existing methods.

[0044] At present, most oil fields in China have entered the middle and late stages of oil development and the tertiary oil recovery stage. The water cut in the produced fluid is 70%-80%, and in some oil fields it has even reached as high as 90%. The amount of produced water is very large. Polymer flooding and ASP flooding are the most important tertiary oil recovery technologies and have been widely promoted in many oil fields.

[0045] There is still a large amount of polymer (mainly polyacrylamide) in the produced water of polymer flooding. The concentration of the polymer is generally 200-1000 mg / L. The presence of the polymer increases the viscosity of the sewage, enhances the oil-carrying capacity of the water phase, and at the same time enhances the emulsification stability of particles such as oil droplets in the water, increasing the difficulty of oil-water separation and adding difficulties to the subsequent treatment of produced water. The treatment of produced water from polymer flooding has become the main limiting factor for the industrial promotion of polymer flooding and is an important issue that needs to be solved urgently in oil fields in China.

[0046] With the wide application of polymer flooding, a large amount of polymer-containing produced water has been generated. After the polymer-containing produced water is treated, according to different water qualities, the main destinations are reinjection, polymer preparation, low-pressure steam boilers, and discharge up to standard. The main treatment methods for produced water are as follows: ①Sedimentation separation - filtration to remove oil and suspended solids. The treatment methods for the oil removal section of sedimentation separation include gravity sedimentation, coagulation sedimentation, electrocoagulation, inclined plate sedimentation, pressure sedimentation, air flotation, and hydrocyclone methods, and sometimes several methods are combined; the treatment methods for the filtration section include walnut shell filtration, quartz sand filtration, fiber ball filtration, manganese sand filtration, membrane separation, etc.; ②Chemical oxidation method to remove polymers, reducing substances, and bacteria in the produced water. Chemical oxidation methods include chemical reagent oxidation, air oxidation, photocatalytic oxidation, etc.; ②Biochemical treatment process to remove organic matter and some inorganic matter in the produced water. The main biological treatment methods include anaerobic biological method, aerobic oxidation method, etc.

[0047] At present, electrocatalytic oxidation treatment is widely used. Electrocatalytic oxidation is a green chemical technology that uses metal oxide electrodes with catalytic properties to generate hydroxyl radicals or other free radicals and groups with strong oxidation ability to attack organic pollutants in the solution and completely decompose them into harmless H2O and CO2. Due to its high oxidation efficiency for organic matter and some reducing substances, simple operation, high equipment integration, and less land occupation, etc., it has shown high degradation ability especially in the treatment of biologically refractory wastewater and has gradually become a research hotspot in the field of water pollution control.

[0048] In electrochemical wastewater treatment, the selection of anode materials directly determines the efficiency of water treatment. There are various types of organic substances in oilfield produced water. The electrochemical oxidation occurring on the anode side involves numerous organic matter mineralization reactions, and the regulation mechanisms of side reactions such as chlorine evolution and hydrogen evolution are complex. Moreover, the anode used for the electrochemical degradation coupling hydrogen evolution reaction of oilfield produced water needs to meet the characteristics of being inexpensive, stable, and highly active. Commercial electrodes have a slow reaction rate, a large overpotential, and poor stability during the electrochemical oxidation process of oilfield produced water. At the same time, although the currently commercial Ru-Ir electrodes and Pt-Pd electrodes have stable performance, they are expensive due to the use of precious metals. Although the BDD electrode only uses inexpensive metals such as boron and carbon, its preparation process uses chemical vapor deposition, and the preparation cost remains high, making it difficult to be used on a large scale. Therefore, it is necessary to specifically develop anode materials suitable for the treatment of oilfield produced water.

[0049] The inventors intend to invent a catalyst with the characteristics of being inexpensive, stable, and highly active to improve the problem that the catalysts for the current treatment of oilfield produced water are difficult to produce on a large scale.

[0050] Figure 1 The flowchart of the method provided in the embodiments of this application is as Figure 1 shown. The embodiments of this application provide a preparation method of a catalyst, and the method includes:

[0051] S1. Dissolve a tin source and a tantalum source in a solvent to obtain a mixed solution;

[0052] In some embodiments, the tin source includes SnCl2·2H2O. The tantalum source includes TaCl5. The solvent includes absolute ethanol.

[0053] In some embodiments, the molar ratio of tin in the tin source to tantalum in the tantalum source is (1-10):1. Controlling the molar ratio of tin in the tin source to tantalum in the tantalum source to be (1-10):1 enables the catalyst to have better activity. During the degradation process of oilfield produced water, the COD degradation rate can reach 99% in 3 hours. Further, the molar ratio of tin in the tin source to tantalum in the tantalum source is (6-8):1. Exemplarily, the molar ratio of tin in the tin source to tantalum in the tantalum source can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1, etc., and it can also be any value within the range of (1-10):1.

[0054] In some embodiments, the relationship between the volume of the solvent and the total mass of the tin source and the tantalum source satisfies: 1 to 3 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution. Further, the relationship between the volume of the solvent and the total mass of the tin source and the tantalum source satisfies: 1.5 to 2.5 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution. The relationship between the volume of the solvent and the total mass of the tin source and the tantalum source can be: 1 gram of the tin source and the tantalum source per 5 milliliters of the solvent solution, 1.2 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 1.4 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 1.6 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 1.8 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 2 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 2.2 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 2.4 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 2.6 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, 2.8 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, or 3 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution, etc. It can also be any value within the range of 1 to 3 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution.

[0055] Specifically, in this embodiment, SnCl2·2H2O and TaCl5 are uniformly mixed according to a certain molar ratio (10:1 - 1:1), 2 g of the mixture is added to 5 mL of anhydrous ethanol, and ultrasonicated until the solution is clear and transparent to obtain a mixed solution.

[0056] S2. Immerse the template with pores in the mixed solution to obtain an intermediate.

[0057] In some embodiments, the template includes microspheres distributed in an array. Further, the material of the microspheres includes polymethyl methacrylate (abbreviation: PMMA). Further still, the particle size of the microspheres is 3 to 100 microns. Preferably, the particle size of the microspheres is 30 to 70 microns. Exemplarily, the particle size of the microspheres can be 3 microns, 10 microns, 20 microns, 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns, or 100 microns, etc. It can also be any value within the range of 3 to 100 microns.

[0058] In some embodiments, the immersion time is 3 to 5 hours. Further, the immersion time is 3.5 to 4.5 hours. Exemplarily, the immersion time can be 3 hours, 3.5 hours, 4 hours, 4.5 hours, or 5 hours, etc. It can also be any value within the range of 3 to 5 hours.

[0059] Specifically, in this embodiment, 4 g of well-arranged PMMA microspheres are added to the mixed solution, immersed for 4 h, vacuum filtered and dried at room temperature for 48 h to obtain an intermediate, and the filtered solution is reused.

[0060] S3. Heat the intermediate to carry out a reaction to obtain a catalyst.

[0061] In some embodiments, the heating rate of the heating reaction is 4 - 6 °C / min; the end temperature of the heating reaction is 500 - 600 °C; the heat preservation time of the heating reaction is 2 - 4 hours. Further, the heating rate of the heating reaction is 4.5 - 5.5 °C / min; the end temperature of the heating reaction is 530 - 570 °C; the heat preservation time of the heating reaction is 2.5 - 3.5 hours. Exemplarily, the heating rate of the heating reaction can be 4 °C / min, 4.5 °C / min, 5 °C / min, 5.5 °C / min or 6 °C / min, etc., and it can also be any value within the range of 2 - 4 °C / min. The end temperature of the heating reaction can be 500 °C, 520 °C, 540 °C, 560 °C, 580 °C or 600 °C, etc., and it can also be any value within the range of 500 - 600 °C. The heat preservation time of the heating reaction can be 2 hours, 2.5 hours, 3 hours, 3.5 hours or 4 hours, etc., and it can also be any value within the range of 2 - 4 hours.

[0062] Specifically, in this embodiment, the intermediate is placed in a tube furnace and heated to 550 °C at 5 °C / min in an inert gas environment and maintained for 3 h to obtain a catalyst.

[0063] This method uses a tin source and a tantalum source to prepare a tantalum-doped tin-containing electrode catalyst, which has good activity and stability. At the same time, compared with the electrode prepared by a noble metal catalyst, it has a lower preparation cost. Compared with the electrode prepared by a lead-containing catalyst, the Sn and Ta used in it are less toxic to water bodies and the human body.

[0064] Based on a general inventive concept, the embodiments of the present application also provide a catalyst, and the catalyst is prepared by using the preparation method of the catalyst provided above.

[0065] This catalyst is prepared based on the above method, and the specific steps of this method can refer to the above embodiments. Since this catalyst adopts some or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, and will not be elaborated one by one here.

[0066] Based on a general inventive concept, the embodiments of the present application also provide an electrode, and the electrode includes the catalyst provided above.

[0067] In some embodiments, the loading amount of the catalyst in the electrode is 1 to 10 mg / cm². Exemplarily, the loading amount of the catalyst in the electrode can be 1 mg / cm², 2 mg / cm², 3 mg / cm², 4 mg / cm², 5 mg / cm², 6 mg / cm², 7 mg / cm², 8 mg / cm², 9 mg / cm², or 10 mg / cm², etc., and it can also be any value within the range of 1 to 10 mg / cm².

[0068] Specifically, the preparation method of the electrode can be: placing 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grinding thoroughly, then adding a certain amount of NMP, and continuing to grind until the slurry is evenly mixed. The slurry is evenly coated on the conductive substrate and placed in an oven to be fully dried to prepare the electrode. The loading amount of the catalyst on the electrode is 1 - 10 mg / cm².

[0069] Based on a general inventive concept, the embodiments of the present application further provide an application of a catalyst, the catalyst includes the catalyst provided above; the application includes using the catalyst as the anode material for the electrochemical treatment of produced water in oilfields.

[0070] The following further elaborates on the present application in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. The experimental methods without specific conditions noted in the following embodiments are usually determined according to national standards. If there are no corresponding national standards, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0071] Example 1

[0072] A preparation method of an electrode, the method includes:

[0073] 1) Uniformly mix SnCl₂·2H₂O and TaCl₅ according to a certain molar ratio (10:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonicate until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution and soak for 4 h, vacuum filter and dry at room temperature for 48 h, and recycle the filtered solution. After the solid is dried, place it in a tubular furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0074] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue to grind until the slurry is evenly mixed. The slurry is evenly coated on the conductive substrate and placed in an oven to be fully dried to prepare the electrode.

[0075] Example 2

[0076] A method for preparing an electrode, the method comprising:

[0077] 1) Uniformly mix SnCl2·2H2O and TaCl5 in a certain molar ratio (9:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonically treat until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, and soak for 4 h, then vacuum filter and dry at room temperature for 48 h, and recycle the filtered solution. After the solid is dried, place it in a tubular furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0078] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is uniformly mixed. Apply the slurry evenly onto the conductive substrate, and place it in an oven to dry thoroughly to prepare the electrode.

[0079] Example 3

[0080] A method for preparing an electrode, the method comprising:

[0081] 1) Uniformly mix SnCl2·2H2O and TaCl5 in a certain molar ratio (8:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonically treat until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, and soak for 4 h, then vacuum filter and dry at room temperature for 48 h, and recycle the filtered solution. After the solid is dried, place it in a tubular furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0082] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is uniformly mixed. Apply the slurry evenly onto the conductive substrate, and place it in an oven to dry thoroughly to prepare the electrode.

[0083] Example 4

[0084] A method for preparing an electrode, the method comprising:

[0085] 1) Uniformly mix SnCl2·2H2O and TaCl5 in a certain molar ratio (7:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonically treat until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, and soak for 4 h, then vacuum filter and dry at room temperature for 48 h, and recycle the filtered solution. After the solid is dried, place it in a tubular furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0086] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly onto the conductive substrate and place it in an oven to dry thoroughly to prepare the electrode.

[0087] Example 5

[0088] A method for preparing an electrode, the method comprising:

[0089] 1) Uniformly mix SnCl2·2H2O and TaCl5 according to a certain molar ratio (6:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and sonicate until the solution is clear and transparent. Add 4 g of well-aligned PMMA microspheres to the solution, soak for 4 h, vacuum filter and dry at room temperature for 48 h, and reuse the filtered solution. After the solid is dried, place it in a tube furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0090] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly onto the conductive substrate and place it in an oven to dry thoroughly to prepare the electrode.

[0091] Example 6

[0092] A method for preparing an electrode, the method comprising:

[0093] 1) Uniformly mix SnCl2·2H2O and TaCl5 according to a certain molar ratio (5:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and sonicate until the solution is clear and transparent. Add 4 g of well-aligned PMMA microspheres to the solution, soak for 4 h, vacuum filter and dry at room temperature for 48 h, and reuse the filtered solution. After the solid is dried, place it in a tube furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0094] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly onto the conductive substrate and place it in an oven to dry thoroughly to prepare the electrode.

[0095] Example 7

[0096] A method for preparing an electrode, the method comprising:

[0097] 1) Mix SnCl2·2H2O and TaCl5 evenly according to a certain molar ratio (4:1). Take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonicate until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, and soak for 4 h. Filter under vacuum and dry at room temperature for 48 h, and reuse the filtered solution. After the solid is dried, place it in a tube furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0098] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind them thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly on the conductive substrate and dry it thoroughly in an oven to prepare the electrode.

[0099] Example 8

[0100] A method for preparing an electrode, the method comprising:

[0101] 1) Mix SnCl2·2H2O and TaCl5 evenly according to a certain molar ratio (3:1). Take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonicate until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, and soak for 4 h. Filter under vacuum and dry at room temperature for 48 h, and reuse the filtered solution. After the solid is dried, place it in a tube furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0102] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind them thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly on the conductive substrate and dry it thoroughly in an oven to prepare the electrode.

[0103] Example 9

[0104] A method for preparing an electrode, the method comprising:

[0105] 1) Mix SnCl2·2H2O and TaCl5 evenly according to a certain molar ratio (2:1). Take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonicate until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, and soak for 4 h. Filter under vacuum and dry at room temperature for 48 h, and reuse the filtered solution. After the solid is dried, place it in a tube furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0106] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly onto the conductive substrate and place it in an oven to dry thoroughly to prepare the electrode.

[0107] Example 10

[0108] A method for preparing an electrode, the method comprising:

[0109] 1) Uniformly mix SnCl2·2H2O and TaCl5 according to a certain molar ratio (1:1), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonicate until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, soak for 4 h, vacuum filter and dry at room temperature for 48 h, and recycle the filtered solution. After the solid is dried, place it in a tubular furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0110] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly onto the conductive substrate and place it in an oven to dry thoroughly to prepare the electrode.

[0111] Comparative Example 1

[0112] A method for preparing an electrode, the method comprising:

[0113] 1) Uniformly mix SnCl2·2H2O and TaCl5 according to a certain molar ratio (10:0), take 2 g of the mixture and add it to 5 mL of absolute ethanol, and ultrasonicate until the solution is clear and transparent. Add 4 g of well-arranged PMMA microspheres to the solution, soak for 4 h, vacuum filter and dry at room temperature for 48 h, and recycle the filtered solution. After the solid is dried, place it in a tubular furnace, heat it to 550 °C at a rate of 5 °C / min in an inert gas environment, and hold for 3 h.

[0114] 2) Place 1 g of the prepared catalyst and 0.1 g of PVDF in an agate mortar, grind thoroughly, then add a certain amount of NMP, and continue grinding until the slurry is evenly mixed. Apply the slurry evenly onto the conductive substrate and place it in an oven to dry thoroughly to prepare the electrode.

[0115] Use the electrodes provided in Examples 1-10 and Comparative Example 1 as anodes for a 3-h COD degradation rate experiment of oilfield produced water. The produced water used in this experiment is from an oilfield, and its measured initial COD content is 4000. Add 1 wt% NaCl to the produced water to increase the conductivity. The electrolytic cell uses a non-diaphragm single-chamber configuration, the cathode uses a Raney nickel mesh, and the effective electrolysis areas of the anode and cathode are both 4 cm 2Electrolysis was carried out in a constant current mode, and the electrolysis current was 10 mA / cm 2 , and the COD degradation rate after 3 hours of electrolysis was measured. The experimental results are shown as follows:

[0116] 3h COD degradation rate % Comparative Example 1 52 Example 1 76 Example 2 81 Example 3 99 Example 4 94 Example 5 92 Example 6 88 Example 7 85 Example 8 84 Example 9 83 Example 10 77

[0117] As can be seen from the above table, using the electrode provided in the embodiment of the present application as the anode to degrade and treat oilfield produced water has a good degradation effect. The COD degradation rate after 3 hours is increased from 52% to at least 77%. And when the molar ratio of SnCl2·2H2O to TaCl5 is 2:1 to 8:1, the COD degradation rate after 3 hours is increased to more than 80%. When the molar ratio of SnCl2·2H2O to TaCl5 is 6:1 to 8:1, the COD degradation rate after 3 hours is increased to more than 90%.

[0118] The electrode provided in Example 2 was further used for the complete degradation experiment of oilfield produced water. The produced water used in this experiment was from an oilfield, and its measured initial COD content was 4000. 1 wt% of NaCl was added to the produced water to increase the conductivity. The electrolytic cell adopted a non-diaphragm single-chamber configuration, and a Raney nickel mesh was used as the cathode. The effective electrolysis areas of the anode and cathode were both 4 cm 2 Electrolysis was carried out in a constant current mode, and the electrolysis current was 10 mA / cm 2 , and the COD degradation rate at different times was measured. The experimental results are shown as follows:

[0119] Electrolysis time COD degradation rate 10 17 20 38 30 56 40 75 60 87 90 95 120 97 180 99 240 100

[0120] As can be obtained from the above table, using the electrode provided in the embodiment of the present application as the anode to degrade and treat oilfield produced water can make the COD degradation rate reach 100% within 4 hours.

[0121] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and the single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and the single numbers within that range, such as 1, 2, 3, 4, 5, and 6, regardless of what the range is. In addition, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0122] In this application, unless otherwise specified, the orientation terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Additionally, in the description of this application's specification, terms such as "include" and "comprise" mean "include but not limited to". In this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this text, "and / or" describes the associated relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural. In this text, "at least one" means one or more, and "multiple" means two or more. "At least one kind", "at least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single item (item) or plural items (items). For example, "at least one (item) of a, b, or c", or, "at least one (item) of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0123] The above are only specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing a catalyst, characterized in that, The method includes: Dissolving a tin source and a tantalum source in a solvent to obtain a mixed solution; Soaking a template with pores in the mixed solution to obtain an intermediate; Performing a heating reaction on the intermediate to obtain a catalyst.

2. The preparation method of the catalyst according to claim 1, characterized in that, The tin source includes SnCl2·2H2O.

3. The preparation method of the catalyst according to claim 1, characterized in that, The tantalum source includes TaCl5.

4. The preparation method of the catalyst according to claim 1, characterized in that, The molar ratio of tin in the tin source to tantalum in the tantalum source is (1 to 10):

1.

5. The preparation method of the catalyst according to claim 4, characterized in that, The molar ratio of tin in the tin source to tantalum in the tantalum source is (6 to 8):

1.

6. The preparation method of the catalyst according to claim 1, characterized in that, The solvent includes absolute ethanol.

7. The preparation method of the catalyst according to claim 1, characterized in that, The relationship between the volume of the solvent and the total mass of the tin source and the tantalum source satisfies: 1 to 3 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution.

8. The preparation method of the catalyst according to claim 7, characterized in that, The relationship between the volume of the solvent and the total mass of the tin source and the tantalum source satisfies: 1.5 to 2.5 grams of the tin source and the tantalum source per 5 milliliters of the solvent solution.

9. The preparation method of the catalyst according to claim 1, characterized in that, The template includes microspheres distributed in an array.

10. The preparation method of the catalyst according to claim 9, characterized in that, The material of the microspheres includes polymethyl methacrylate.

11. The preparation method of the catalyst according to claim 9, characterized in that, The particle size of the microspheres is 3 to 100 microns.

12. The preparation method of the catalyst according to claim 11, characterized in that, The particle size of the microspheres is 30 to 70 microns.

13. The preparation method of the catalyst according to claim 1, characterized in that, The soaking time is 3 to 5 hours.

14. The preparation method of the catalyst according to claim 13, wherein, The soaking time is 3.5 to 4.5 hours.

15. The preparation method of the catalyst according to claim 1, characterized in that, The heating rate of the heating reaction is 4 to 6 °C / min; and / or The end temperature of the heating reaction is 500 to 600 °C; and / or The heat preservation time of the heating reaction is 2 to 4 hours.

16. The preparation method of the catalyst according to claim 1, characterized in that, The heating rate of the heating reaction is 4.5 to 5.5 °C / min; and / or The end temperature of the heating reaction is 530 to 570 °C; and / or The heat preservation time of the heating reaction is 2.5 to 3.5 hours.

17. A catalyst, characterized in that, The catalyst is prepared by the preparation method of the catalyst described in claims 1 to 16.

18. An electrode, characterized in that, The electrode includes the catalyst described in claim 17.

19. The electrode according to claim 18, characterized in that, The loading amount of the catalyst in the electrode is 1 to 10 mg / cm².

20. Application of a catalyst, characterized in that, The catalyst includes the catalyst described in claim 17; the application includes using the catalyst as the anode material for the electrochemical treatment of produced water in oil fields.

Images