A catalyst for catalytic wet hydrogen peroxide oxidation reaction based on electromagnetic induction heating and a preparation method and application thereof

Abstract

This invention discloses a catalyst for catalytic wet hydrogen peroxide oxidation (WWPO) reactions based on electromagnetic induction heating, its preparation method, and its application, belonging to the field of chemical catalyst technology. In this invention, magnetic nanomaterial CoFe2O4 is synthesized in an alkaline solution using a co-precipitation method with soluble cobalt and soluble iron salts. A high specific surface area CWPO catalyst, CoFe2O4@C, is prepared by layering and co-assembling the magnetic nanomaterial CoFe2O4 with carbon precursors resorcinol and formaldehyde. The preparation method is simple, low-cost, and easy to mass-produce. It is used for the CWPO degradation reaction of antibiotic pollutants such as tetracycline hydrochloride. The high specific surface area C shell provides a large number of tetracycline hydrochloride adsorption sites. CoFe2O4 can effectively respond to the heat generated by the alternating electromagnetic field and efficiently catalyze the formation of OH· from H2O2, exhibiting high catalytic activity, selectivity, and stability in antibiotic CWPO reactions.

Description

Technical Field

[0001] This invention belongs to the field of chemical catalyst technology, specifically relating to a catalyst for catalytic wet hydrogen peroxide oxidation reaction based on electromagnetic induction heating, its preparation method, and its application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Catalytic wet hydrogen peroxide (CWPO) is a widely used wastewater treatment process with advantages such as simple operation, economy, and environmental friendliness. Reaction temperature is the main factor affecting heterogeneous CWPO reactions. Currently, heating methods for heterogeneous reactions mainly focus on steam heating, resistance heating, reactant preheating, and microwave heating. Heat flows from the heating equipment to the liquid phase and then to the catalyst surface, with the liquid-solid interface temperature determined by the liquid temperature. However, since the target reaction occurs on the catalyst surface, if the heat transfer direction is directly from the heating equipment to the catalyst particle surface, the catalytic efficiency of the catalyst will be greatly improved.

[0004] Alternating current electromagnetic induction heating is 30%-50% more efficient than flame furnaces and 20%-30% more efficient than resistance furnaces. Moreover, it does not produce open flames, exhaust gases, or smoke. It has advantages such as high thermal efficiency, fast heating speed, energy saving, environmental protection, safety, and reliability. More importantly, electromagnetic induction heating can directly act on the magnetic catalyst in the reactor. The surface temperature of the catalyst is much higher than the liquid phase temperature, avoiding heat loss caused by the heat transfer process. Applying this new energy-saving, environmentally friendly, and safe "green heating" method to heterogeneous CWPO reactions has great potential.

[0005] Therefore, there is an urgent need to develop a high-performance CWPO reaction catalyst that can efficiently respond to electromagnetic field-induced heat generation. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a catalyst for the catalytic wet hydrogen peroxide reaction based on electromagnetic induction heating, its preparation method, and its application, thereby solving the problems of low catalytic efficiency and inefficient electromagnetic induction heating in existing CWPO reaction catalysts.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing a catalyst for a wet hydrogen peroxide oxidation reaction based on electromagnetic induction heating, the preparation method comprising the following steps:

[0009] S1. Dissolve soluble cobalt salt and soluble iron salt in water, heat, adjust the pH of the solution to alkaline with an alkaline reagent, stir, and obtain cobalt ferrite crystals.

[0010] S2. Grind the cobalt ferrite crystals obtained in S1 into powder, and perform high-temperature heat treatment in air atmosphere to obtain cobalt ferrite nanomagnetic material.

[0011] S3. Dissolve the copolymer pluronic F127 in water, add the nano-magnetic material cobalt ferrite suspension, heat and stir, add carbon precursor material, adjust the pH of the solution to alkaline with an alkaline reagent, stir the reaction, and obtain a solid sample.

[0012] S4. Grind the solid sample obtained in S3 into powder and perform high-temperature heat treatment under a protective gas and a small amount of water vapor to obtain a catalyst for the catalytic wet hydrogen peroxide reaction based on electromagnetic induction heating.

[0013] In some embodiments of the present invention, in step S1, the soluble cobalt salt includes, but is not limited to, at least one of cobalt nitrate, cobalt chloride, cobalt sulfate, and cobalt acetate;

[0014] The soluble iron salts include, but are not limited to, at least one of ferric nitrate, ferric chloride, ferric sulfate, and ferric acetate;

[0015] The molar ratio between the soluble cobalt salt and the soluble iron salt is 1:1 to 1:3.

[0016] In some embodiments of the present invention, in step S1, the heating is a condensation reflux heating to 60-90°C;

[0017] In step S1, the alkaline reagent includes, but is not limited to, one or more combinations of sodium hydroxide, urea, and ammonia; the pH of the solution is adjusted to 9-11 using the alkaline reagent.

[0018] In some embodiments of the present invention, in step S2, the high-temperature heat treatment is carried out at a temperature of 400-600°C for a duration of 2-5 hours.

[0019] In some embodiments of the present invention, in step S3, the mass ratio of the copolymer pluronic F127 to the cobalt ferrite nanomaterial is 20:1-60:1, and the concentration of the cobalt ferrite nanomaterial in the entire reaction system is 0.5-5 g / L. The entire reaction system is the reaction system of step S3, which includes the copolymer pluronic F127, water, the cobalt ferrite nanomaterial, a carbon precursor material, and an alkaline reagent.

[0020] In some embodiments of the present invention, in step S3, the heating is a condensation reflux heating to 50-80°C;

[0021] In step S3, the stirring time for the first stirring is 1-3 hours, and the stirring time for the second stirring is 12-36 hours.

[0022] In step S3, the carbon precursor material is a mixture of resorcinol and formaldehyde; the concentration of resorcinol in the entire reaction system is 10-30 g / L; preferably, the formaldehyde is a 37 wt.% formaldehyde solution, and the mass ratio of resorcinol to the 37 wt.% formaldehyde solution is 1:1-1:5. The entire reaction system is also the reaction system of step S3, which includes the copolymer pluronic F127, water, cobalt ferrite nanomaterial, carbon precursor material (resorcinol and formaldehyde), and alkaline reagent.

[0023] In step S3, the alkaline reagent includes, but is not limited to, one or more combinations of sodium hydroxide, urea, and ammonia; the pH of the solution is adjusted to 8-11 using the alkaline reagent.

[0024] In some embodiments of the present invention, in step S4, the flow rate of the protective gas is 50-300 mL / min, and the flow rate of the water vapor is 2-50 mL / min.

[0025] In step S4, the high-temperature heat treatment is carried out at a temperature of 600-900℃ for a duration of 2-5 hours.

[0026] In a second aspect, the present invention provides a catalyst for a wet hydrogen peroxide reaction based on electromagnetic induction heating, which is prepared by the above-described preparation method.

[0027] A third aspect of the present invention provides the application of the above-described catalyst for catalytic wet hydrogen peroxide oxidation based on electromagnetic induction heating in an electromagnetic induction heating-driven catalytic wet hydrogen peroxide oxidation reaction.

[0028] Preferably, the catalytic wet hydrogen peroxide oxidation reaction is a degradation reaction of antibiotic pollutants in wastewater.

[0029] More preferably, the antibiotic contaminant is tetracycline hydrochloride.

[0030] A fourth aspect of the present invention provides a method for degrading tetracycline hydrochloride, comprising the following steps:

[0031] The above-mentioned catalyst for catalytic wet hydrogen peroxide oxidation based on electromagnetic induction heating was added to a solution containing tetracycline hydrochloride, stirred, and hydrogen peroxide was added. The reaction system was then heated by electromagnetic induction using an electromagnetic induction device to drive the reaction. Once the reaction was complete, the degradation of tetracycline hydrochloride was finished.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention discloses a method for preparing a catalyst for the catalytic wet hydrogen peroxide reaction based on electromagnetic induction heating. In an alkaline solution, soluble cobalt salts and soluble iron salts are used to synthesize magnetic nanomaterial cobalt ferrite (CoFe2O4) via co-precipitation and subsequent high-temperature heat treatment. A high specific surface area CoFe2O4@C core-shell catalyst is prepared by the layered co-assembly of the magnetic nanomaterial CoFe2O4 with carbon precursors resorcinol and formaldehyde, followed by high-temperature heat treatment. The preparation method of this invention is simple, low-cost, and easy to prepare in large quantities, facilitating large-scale production.

[0034] The high specific surface area CoFe2O4@C core-shell catalyst prepared in this invention consists of an induction-generating heat-generating component, a catalytically active component CoFe2O4, and a high specific surface area adsorbent component C coated on its surface. This catalyst can directly reach high temperatures through induction heating based on the principle of electromagnetic induction, avoiding energy consumption and the generation of waste gas and dust in traditional heating and heat transfer processes, thus providing technical support for the green and low-carbon transformation of industrial catalysis. When applied to the CWPO reaction driven by electromagnetic induction heating, the high specific surface area carbon shell can provide a large number of tetracycline hydrochloride adsorption sites. CoFe2O4 can effectively respond to the heat generated by the alternating electromagnetic field and efficiently catalyze the generation of OH· from H2O2. In the CWPO reaction, it exhibits stable and efficient catalytic activity, selectivity, and stability, achieving a 100% removal rate of tetracycline hydrochloride and remaining stable for 100 hours without deactivation. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0036] Figure 1 This is a high-resolution transmission electron microscope image of the CWPO reaction catalyst prepared in Example 1 of the present invention;

[0037] Figure 2 This is a high-resolution transmission electron microscope image of the CWPO reaction catalyst prepared in Example 1 of the present invention;

[0038] Figure 3 The diagram shows the reaction results when the CWPO catalyst prepared in Example 1 of this invention is applied to a CWPO catalytic reaction driven by electromagnetic induction heating.

[0039] Figure 4 The graph shows the reaction results when the CWPO catalyst prepared in Comparative Example 1 of this invention is applied to a conventionally heated CWPO catalytic reaction. Detailed Implementation

[0040] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.

[0041] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0042] There are no particular restrictions on the purity of any raw materials used in this invention. However, it is preferred to use analytical grade or conventional purity used in the field of photocatalyst preparation.

[0043] This invention provides a method for preparing a catalyst for a wet hydrogen peroxide oxidation reaction based on electromagnetic induction heating, the preparation method comprising the following steps:

[0044] S1. Dissolve soluble cobalt salt and soluble iron salt in water, heat, adjust the pH of the solution to alkaline with an alkaline reagent, stir, and obtain cobalt ferrite crystals.

[0045] S2. Grind the cobalt ferrite crystals obtained in S1 into powder, and perform high-temperature heat treatment in air atmosphere to obtain cobalt ferrite nanomagnetic material.

[0046] S3. Dissolve the copolymer pluronic F127 in water, add the nano-magnetic material cobalt ferrite suspension, heat and stir, add carbon precursor material, adjust the pH of the solution to alkaline with an alkaline reagent, stir the reaction, and obtain a solid sample.

[0047] S4. Grind the solid sample obtained in S3 into powder and perform high-temperature heat treatment under a protective gas and a small amount of water vapor to obtain a catalyst for the catalytic wet hydrogen peroxide reaction based on electromagnetic induction heating.

[0048] In this invention, cobalt ferrite (CoFe2O4) magnetic nanomaterials are synthesized in an alkaline solution using a co-precipitation method with soluble cobalt salts and soluble iron salts. A high specific surface area CWPO catalyst, CoFe2O4@C, is prepared by layering and co-assembling the magnetic nanomaterial CoFe2O4 with carbon precursors resorcinol and formaldehyde, and then using water vapor to create pores.

[0049] In a specific embodiment of the present invention, in step S1, the soluble cobalt salt includes, but is not limited to, at least one of cobalt nitrate, cobalt chloride, cobalt sulfate, and cobalt acetate; the soluble iron salt includes, but is not limited to, at least one of ferric nitrate, ferric chloride, ferric sulfate, and ferric acetate.

[0050] In one specific embodiment of the present invention, the molar ratio between the soluble cobalt salt and the soluble iron salt is 1:1 to 1:3, specifically 1:1, 1:2, or 1:3, etc.

[0051] In a specific embodiment of the present invention, in step S1, the heating is a condensation reflux temperature rise to 60-90°C, specifically 60°C, 65°C, 68°C, 73°C, 78°C, 80°C, 82°C, 87°C, 89°C or 90°C, etc.

[0052] In a specific embodiment of the present invention, in step S1, the alkaline reagent includes, but is not limited to, one or more combinations of sodium hydroxide, urea and ammonia; the pH of the solution is adjusted to 9-11 using the alkaline reagent, specifically 9, 10 or 11.

[0053] In a specific embodiment of the present invention, in step S1, the stirring time is 2-5 hours, specifically 2 hours, 2.4 hours, 3 hours, 3.5 hours, 4 hours, 4.8 hours, or 5 hours.

[0054] In a specific embodiment of the present invention, in step S1, after stirring is completed, the solid product is centrifuged, washed, and dried to obtain cobalt ferrite crystals.

[0055] The number of centrifugal washing cycles is 3-10 times, specifically 3, 4, 5, 6, 7, 8, 9, or 10 times. The solutions used for centrifugal washing are aqueous solutions and ethanol solutions.

[0056] The drying temperature is 50-80℃, specifically 50℃, 55℃, 60℃, 65℃, 68℃, 73℃, 78℃, or 80℃. The drying time is 6-12 hours, specifically 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0057] In a specific embodiment of the present invention, in step S2, the high-temperature heat treatment is performed at a temperature of 400-600℃, specifically 400℃, 450℃, 470℃, 490℃, 500℃, 530℃, 580℃, or 600℃, etc.; the treatment time is 2-5 hours, specifically 2 hours, 2.4 hours, 3 hours, 3.5 hours, 4 hours, 4.8 hours, or 5 hours, etc. High-temperature heat treatment in an air atmosphere ensures that the sample to be treated fully crystallizes to obtain the nano-magnetic material cobalt ferrite CoFe2O4.

[0058] In a specific embodiment of the present invention, in step S3, the mass ratio of the copolymer pluronic F127 to the nanomagnetic material cobalt ferrite is 20:1-60:1, specifically 20:1, 25:1, 30:1, 25:1, 40:1, 45:1, 50:1, 58:1, or 60:1, etc.; the concentration of the nanomagnetic material cobalt ferrite in the entire reaction system is 0.5-5 g / L, specifically 0.5 g / L, 0.8 g / L, 1 g / L, 1.5 g / L, 2 g / L, 2.8 g / L, 3 g / L, 3.7 g / L, 4 g / L, 4.5 g / L, or 5 g / L, etc.

[0059] In a specific embodiment of the present invention, in step S3, the heating is a condensation reflux temperature rise to 50-80°C, specifically 50°C, 55°C, 60°C, 65°C, 68°C, 73°C, 78°C or 80°C, etc.

[0060] In a specific embodiment of the present invention, in step S3, the stirring time for the first stirring is 1-3 hours, specifically 1 hour, 2 hours or 3 hours; the stirring time for the second stirring is 12-36 hours, specifically 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, 25 hours, 26 hours, 27 hours, 28 hours, 29 hours, 30 hours, 31 hours, 32 hours, 33 hours, 34 hours, 35 hours or 36 hours, etc.

[0061] In a specific embodiment of the present invention, in step S3, the carbon precursor material is a mixture of resorcinol and formaldehyde; the concentration of resorcinol in the entire reaction system is 10-30 g / L, specifically 10 g / L, 15 g / L, 18 g / L, 20 g / L, 25 g / L, 27 g / L or 30 g / L, etc.

[0062] The formaldehyde is a 37 wt.% formaldehyde solution, and the mass ratio of resorcinol to the 37 wt.% formaldehyde solution is 1:1 to 1:5, specifically 1:1, 1:2, 1:3, 1:4 or 1:5, etc.

[0063] In a specific embodiment of the present invention, in step S3, the alkaline reagent includes one or more combinations of sodium hydroxide, urea and ammonia water; the pH of the solution is adjusted to 8-11 using the alkaline reagent, specifically 8, 9, 10 or 11.

[0064] In a specific embodiment of the present invention, in step S3, after adjusting the pH and completing the stirring reaction, the solid product is centrifuged, washed, and dried.

[0065] The number of centrifugal washing cycles is 3-10 times, specifically 3, 4, 5, 6, 7, 8, 9, or 10 times. The solutions used for centrifugal washing are aqueous solutions and ethanol solutions.

[0066] The drying temperature is 50-80℃, specifically 50℃, 55℃, 60℃, 65℃, 68℃, 73℃, 78℃, or 80℃. The drying time is 6-12 hours, specifically 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0067] In one specific embodiment of the present invention, in step S4, the flow rate of the protective gas is 50-300 mL / min, specifically 50 mL / min, 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, or 300 mL / min, etc. The protective gas includes, but is not limited to, nitrogen, argon, or helium. Water vapor originates from a steam generator or is carried over with the protective gas. The flow rate of the water vapor is 2-50 mL / min, specifically 2 mL / min, 5 mL / min, 10 mL / min, 15 mL / min, 20 mL / min, 25 mL / min, 30 mL / min, 40 mL / min, or 50 mL / min, etc.

[0068] In a specific embodiment of the present invention, in step S4, the high-temperature heat treatment is carried out at a temperature of 600-900℃, specifically 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 880℃, or 900℃, etc.; and the treatment time is 2-5 hours, specifically 2 hours, 3 hours, 4 hours, or 5 hours, etc.

[0069] Another typical embodiment of the present invention provides a catalytic wet hydrogen peroxide reaction catalyst based on electromagnetic induction heating, which is prepared by the above preparation method.

[0070] Specifically, the CWPO reaction catalyst based on electromagnetic induction heating consists of an induction-generating component, an active component CoFe2O4, and a high specific surface area component C coated on its surface. Furthermore, the CWPO reaction catalyst has a core-shell structure, with CoFe2O4 as the core and C as the shell. The high specific surface area C shell provides a large number of tetracycline hydrochloride adsorption sites. CoFe2O4 can effectively respond to the heat generated by the alternating electromagnetic field and efficiently catalyze the formation of OH· from H2O2. In antibiotic-related CWPO reactions, it exhibits highly efficient catalytic activity, selectivity, and stability.

[0071] Another typical embodiment of the present invention provides the application of the above-mentioned catalyst for catalytic wet hydrogen peroxide reaction based on electromagnetic induction heating in an electromagnetic induction heating driven catalytic wet hydrogen peroxide reaction.

[0072] The catalytic wet hydrogen peroxide oxidation reaction is a degradation reaction of antibiotic pollutants in wastewater. More preferably, the antibiotic pollutant is tetracycline hydrochloride. The catalyst provided by this invention exhibits stable and efficient catalytic activity, selectivity, and stability, achieving a 100% removal rate of tetracycline hydrochloride and remaining stable for 100 hours without deactivation.

[0073] Another typical embodiment of the present invention provides a method for degrading tetracycline hydrochloride, comprising the following steps:

[0074] The above-mentioned catalyst for catalytic wet hydrogen peroxide oxidation based on electromagnetic induction heating was added to a solution containing tetracycline hydrochloride, stirred, and hydrogen peroxide was added. The reaction system was then heated by electromagnetic induction using an electromagnetic induction device to drive the reaction. Once the reaction was complete, the degradation of tetracycline hydrochloride was finished.

[0075] In one specific embodiment of the present invention, an electromagnetic induction heating reactor can be used to carry out the CWPO reaction. Before the reaction, the catalytic wet hydrogen peroxide reaction catalyst based on electromagnetic induction heating is placed in a beaker containing the target pollutant. The beaker is placed in an electromagnetic induction coil and stirred at room temperature. Then, hydrogen peroxide solution is added, and the electromagnetic induction device is turned on to drive the reaction through electromagnetic induction heating.

[0076] The stirring time at room temperature is 0.5-1.5 hours, specifically 0.5 hours, 1 hour, or 1.5 hours.

[0077] The electromagnetic induction heating reactor uses an electromagnetic heating frequency of 235 kHz and a current of 200 A. In the method of this invention, tetracycline hydrochloride can be completely removed from the target pollutant in 10-20 minutes, achieving a removal rate of up to 100%, demonstrating very high removal efficiency.

[0078] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0079] Example 1

[0080] This embodiment provides a CWPO reaction catalyst based on electromagnetic induction heating, the preparation method of which includes the following steps:

[0081] S1. Dissolve 67 mmol of cobalt chloride hexahydrate (II) and 134 mmol of ferric chloride hexahydrate (III) in 100 mL of distilled water, then transfer to a 250 mL round-bottom flask, place in an oil bath, and reflux to 75 °C. Add 80 mL of 1 mol / L ammonium hydroxide solution dropwise using a peristaltic pump while continuously and vigorously stirring. When the solution turns dark brown, continue vigorous stirring for 30 min to ensure complete ferrite crystal formation. Wash three times each with deionized water and anhydrous ethanol by centrifugation, and dry the sample at 60 °C for 12 h.

[0082] S2. Grind the solid sample obtained in S1 into powder and perform high-temperature heat treatment at 500℃ in air atmosphere at 100mL / min for 2h to ensure full crystallization, thereby obtaining the nanomagnetic material CoFe2O4.

[0083] S3. Dissolve 5g of the copolymer pluronic F127 in 50mL of H2O, place the solution in a 500mL round-bottom flask, and add 5mL of a suspension of the nano-magnetic material CoFe2O4 (concentration 17mg / mL). -1 The mixture was stirred at 70°C for 2 hours, then 2 g of resorcinol and 3 mL of 37 wt.% formaldehyde solution were added, followed by 50.0 mL of 0.1 mol / L sodium hydroxide solution. The mixture was stirred at 70°C for 24 hours, then centrifuged and washed three times each with ethanol and deionized water, and dried in an oven at 60°C for 12 hours.

[0084] S4. Grind the solid sample obtained in S3 into powder and perform high-temperature heat treatment at 750℃, 100mL / min N2, and 4mL / min water vapor atmosphere for 2 hours to obtain a specific surface area of ​​1135m². 2 / g of CoFe2O4@C material.

[0085] Example 2

[0086] This embodiment provides a CWPO reaction catalyst based on electromagnetic induction heating, the preparation method of which includes the following steps:

[0087] S1. Dissolve 67 mmol of cobalt chloride hexahydrate (II) and 198 mmol of ferric chloride hexahydrate (III) in 100 mL of distilled water, then transfer to a 250 mL round-bottom flask, place in an oil bath, and reflux to 90 °C. Add 80 mL of 1 mol / L ammonium hydroxide solution dropwise using a peristaltic pump while continuously and vigorously stirring. When the solution turns dark brown, continue vigorous stirring for 30 min to ensure complete ferrite crystal formation. Wash three times each with deionized water and anhydrous ethanol, and dry the sample at 60 °C for 12 h.

[0088] S2. Grind the solid sample obtained in S1 into powder and perform high-temperature heat treatment at 600℃ in air atmosphere at 100mL / min for 2h to ensure full crystallization, thereby obtaining the nanomagnetic material CoFe2O4.

[0089] S3. Dissolve 5g of the copolymer pluronic F127 in 50mL of H2O, place the solution in a 500mL round-bottom flask, and add 5mL of a suspension of the nano-magnetic material CoFe2O4 (concentration 17mg / mL). -1 The mixture was stirred at 70°C for 2 hours, then 2 g of resorcinol and 3 mL of 37 wt.% formaldehyde solution were added, followed by 50.0 mL of 0.1 mol / L sodium hydroxide solution. The mixture was stirred at 70°C for 24 hours, then centrifuged and washed three times each with ethanol and deionized water, and dried in an oven at 60°C for 12 hours.

[0090] S4. Grind the solid sample obtained in S3 into powder and perform high-temperature heat treatment for 2 hours at 750℃, 100mL / min N2 and 4mL / min water vapor atmosphere to obtain high specific surface area CoFe2O4@C material.

[0091] Example 3

[0092] This embodiment provides a CWPO reaction catalyst based on electromagnetic induction heating, the preparation method of which includes the following steps:

[0093] S1. Dissolve 67 mmol of cobalt chloride hexahydrate (II) and 134 mmol of ferric chloride hexahydrate (III) in 100 mL of distilled water, then transfer to a 250 mL round-bottom flask, place in an oil bath, and reflux to 75 °C. Add 80 mL of 1 mol / L ammonium hydroxide solution dropwise using a peristaltic pump while continuously and vigorously stirring. When the solution turns dark brown, continue vigorous stirring for 30 min to ensure complete ferrite crystal formation. Wash three times each with deionized water and anhydrous ethanol by centrifugation, and dry the sample at 60 °C for 12 h.

[0094] S2. Grind the solid sample obtained in S1 into powder and perform high-temperature heat treatment at 500℃ in air atmosphere at 100mL / min for 2h to ensure full crystallization, thereby obtaining the nanomagnetic material CoFe2O4.

[0095] S3. Dissolve 5g of the copolymer pluronic F127 in 50mL of H2O, place the solution in a 500mL round-bottom flask, and add 5mL of a suspension of the nano-magnetic material CoFe2O4 (concentration 17mg / mL). -1The mixture was stirred at 70°C for 2 hours, then 2 g of resorcinol and 3 mL of 37 wt.% formaldehyde solution were added, followed by 50.0 mL of 0.1 mol / L sodium hydroxide solution. The mixture was stirred at 70°C for 24 hours, washed three times each with ethanol and deionized water, and dried in an oven at 60°C for 12 hours.

[0096] S4. Grind the solid sample obtained in S3 into powder and perform high-temperature heat treatment for 2 hours at 900℃, 100mL / min N2, and 10mL / min water vapor atmosphere to obtain a specific surface area of ​​1057m². 2 / g of CoFe2O4@C material.

[0097] Comparative Example 1

[0098] This comparative example provides a conventional heating method for preparing a CWPO reaction catalyst, which is the same as that in Example 1 and will not be described again here.

[0099] Comparative Example 2

[0100] This comparative example provides a C-shell-free CWPO reaction catalyst based on electromagnetic induction heating, the preparation method of which includes the following steps:

[0101] S1. Dissolve 67 mmol of cobalt chloride hexahydrate (II) and 134 mmol of ferric chloride hexahydrate (III) in 100 mL of distilled water, then transfer to a 250 mL round-bottom flask, place in an oil bath, and reflux to 75 °C. Add 80 mL of 1 mol / L ammonium hydroxide solution dropwise using a peristaltic pump while continuously and vigorously stirring. When the solution turns dark brown, continue vigorous stirring for 30 min to ensure complete ferrite crystal formation. Wash three times each with deionized water and anhydrous ethanol by centrifugation, and dry the sample at 60 °C for 12 h.

[0102] S2. Grind the solid sample obtained in S1 into powder and perform high-temperature heat treatment at 500℃ in air atmosphere at 100mL / min for 2h to ensure full crystallization, thereby obtaining the nanomagnetic material CoFe2O4.

[0103] Performance verification

[0104] 1. To verify the activity and stability of the catalysts in the examples and comparative examples, the catalysts in the examples and comparative examples were used for CWPO catalytic reaction driven by electromagnetic induction heating. Specifically, before the reaction, 10 mg of CWPO catalyst was placed in a beaker containing 50 mL of tetracycline hydrochloride solution (concentration of 60 mg / L), the beaker was placed in an electromagnetic induction coil, and stirred at room temperature for 1 h. Then, 3 mL of 30 wt.% H2O2 solution was added, the electromagnetic induction device was turned on, the electromagnetic heating frequency was 235 kHz, and the current was 200 A.

[0105] Tests showed that the CWPO reaction catalyst prepared in Example 1 exhibited good catalytic activity under electromagnetic induction heating conditions, and tetracycline hydrochloride was completely degraded within 10 minutes. Figure 1 , Figure 2 The images show high-resolution transmission electron microscopy (TEM) images of the CWPO reaction catalyst prepared in Example 1 based on electromagnetic induction heating. As can be seen from the images, C in the CWPO reaction catalyst prepared in this example is covered on the surface of CoFe2O4, forming a core-shell structure. Figure 3 The curve showing the trend of tetracycline hydrochloride concentration over degradation time is obtained by... Figure 3 It can be seen that tetracycline hydrochloride is completely degraded in 10 minutes.

[0106] Tests showed that the CWPO reaction catalyst prepared in Example 2 also exhibited good catalytic activity under electromagnetic induction heating conditions, and tetracycline hydrochloride was completely degraded after 20 minutes.

[0107] Tests showed that the CWPO reaction catalyst prepared in Example 3 also exhibited good catalytic activity under electromagnetic induction heating conditions, and tetracycline hydrochloride was completely degraded within 15 minutes.

[0108] Testing showed that the C-shell-free CWPO catalyst prepared in Comparative Example 2, when applied to an electromagnetic induction heating-driven CWPO catalytic reaction, required 25 minutes to completely degrade tetracycline hydrochloride. This indicates that the adsorption of tetracycline hydrochloride by the C-shell is beneficial for its further degradation.

[0109] 2. Using a conventional heating method, the CWPO catalytic reaction was catalyzed using the conventionally heated CWPO catalyst provided in Comparative Example 1. Specifically, 10 mg of CWPO catalyst (Comparative Example 1) was placed in a beaker containing 50 mL of tetracycline hydrochloride solution (concentration 60 mg / L), stirred at room temperature for 1 hour, and then heated to 35°C using a water bath (this temperature is consistent with the solution temperature heated by electromagnetic induction heating when the catalyst in Example 1 catalyzes the CWPO catalytic reaction). 3 mL of 30 wt.% H2O2 solution was added to initiate the reaction.

[0110] Tests showed that in Comparative Example 1, the conventionally heated CWPO reaction catalyst required 40 minutes to completely degrade tetracycline hydrochloride. Figure 4 The CWPO reaction activity was worse than that of the electromagnetic induction heating driven in Example 1, indicating that the electromagnetic induction driven CWPO reaction exhibited higher activity.

[0111] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for a wet hydrogen peroxide oxidation reaction based on electromagnetic induction heating, characterized in that, The preparation method includes the following steps: S1. Dissolve soluble cobalt salt and soluble iron salt in water, heat, adjust the pH of the solution to alkaline with an alkaline reagent, stir, and obtain cobalt ferrite crystals. S2. Grind the cobalt ferrite crystals obtained in S1 into powder, and perform high-temperature heat treatment in air atmosphere to obtain cobalt ferrite nanomagnetic material. S3. Dissolve the copolymer pluronic F127 in water, add a suspension of cobalt ferrite nanomaterial, heat and stir, add carbon precursor material, adjust the pH of the solution to alkaline with an alkaline reagent, stir the reaction, and obtain a solid sample; the carbon precursor material is a mixture of resorcinol and formaldehyde. S4. Grind the solid sample obtained in S3 into powder and perform high-temperature heat treatment under a protective gas and a small amount of water vapor to obtain a catalyst for the catalytic wet hydrogen peroxide reaction based on electromagnetic induction heating.

2. The preparation method according to claim 1, characterized in that, In step S1, the soluble cobalt salt includes at least one of cobalt nitrate, cobalt chloride, cobalt sulfate, and cobalt acetate; The soluble iron salt includes at least one of ferric nitrate, ferric chloride, ferric sulfate, and ferric acetate; The molar ratio between the soluble cobalt salt and the soluble iron salt is 1:1 to 1:

3.

3. The preparation method according to claim 1, characterized in that, In step S1, the heating is a condensation reflux heating to 60-90°C; In step S1, the alkaline reagent includes one or more combinations of sodium hydroxide, urea, and ammonia water; the pH of the solution is adjusted to a pH of 9-11 using the alkaline reagent.

4. The preparation method according to claim 1, characterized in that, In step S2, the high-temperature heat treatment is carried out at a temperature of 400-600℃ for a duration of 2-5 hours.

5. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the copolymer pluronic F127 to the nanomagnetic material cobalt ferrite is 20:1-60:1, and the concentration of the nanomagnetic material cobalt ferrite in the entire reaction system is 0.5-5 g / L.

6. The preparation method according to claim 1, characterized in that, In step S3, the heating is a condensation reflux temperature rise to 50-80℃; In step S3, the stirring time for the first stirring is 1-3 hours, and the stirring time for the second stirring is 12-36 hours. In step S3, the carbon precursor material is a mixture of resorcinol and formaldehyde; the concentration of resorcinol in the entire reaction system is 10-30 g / L. In step S3, the alkaline reagent includes one or more combinations of sodium hydroxide, urea, and ammonia water; the pH of the solution is adjusted to 8-11 using the alkaline reagent.

7. The preparation method according to claim 6, characterized in that, In step S3, the formaldehyde is a 37 wt.% formaldehyde solution, and the mass ratio of resorcinol to the 37 wt.% formaldehyde solution is 1:1 to 1:

5.

8. The preparation method according to claim 1, characterized in that, In step S4, the flow rate of the protective gas is 50-300 mL / min, and the flow rate of the water vapor is 2-50 mL / min; In step S4, the high-temperature heat treatment is carried out at a temperature of 600-900℃ for a duration of 2-5 hours.

9. A catalyst for catalytic wet hydrogen peroxide oxidation reaction based on electromagnetic induction heating, characterized in that, It is prepared by any one of the preparation methods described in claims 1-8.

10. The application of the catalytic wet hydrogen peroxide reaction catalyst based on electromagnetic induction heating as described in claim 9 in the electromagnetic induction heating driven catalytic wet hydrogen peroxide reaction.

11. The application as described in claim 10, characterized in that, The catalytic wet hydrogen peroxide oxidation reaction is a degradation reaction of antibiotic pollutants in wastewater.

12. The application as described in claim 11, characterized in that, The antibiotic contaminant is tetracycline hydrochloride.

13. A method for degrading tetracycline hydrochloride, characterized in that, Includes the following steps: The catalytic wet hydrogen peroxide reaction catalyst based on electromagnetic induction heating as described in claim 9 is added to a solution containing tetracycline hydrochloride, stirred, hydrogen peroxide is added, and the reaction system is electromagnetically heated by an electromagnetic induction device to drive the reaction. Once the reaction is complete, the degradation of tetracycline hydrochloride is finished.

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