Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment and preparation method of Janus structure nanosheet array ozone catalyst

Abstract

The invention relates to a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater and a preparation method thereof.The catalyst is characterized in that Ti3AlC2, HF, tannic acid and polyethyleneimine are used for preparing a hydrophilic layer substrate with positive charges, a large number of metal ion coordination active sites are formed, then Mn < 2 + > and Fe < 3 + > are loaded, a functional layer is constructed in a gradient magnetic field, and the functional layer is formed; according to different response characteristics of Mn < 2 + > / Fe < 3 + > ions in a magnetic field, gradient distribution of inner-layer Mn enrichment and outer-layer Fe enrichment is achieved, then a hydrophobic layer precursor solution is dispensed, and finally the catalyst is soaked in a calcium chloride solution to obtain the Janus structure nanosheet array ozone catalyst. Through double-metal site loading and gradient structure design, the reaction activation energy is reduced, the hydroxyl free radical generation efficiency is improved, the ozone decomposition efficiency and the pollutant degradation rate are improved, and the prepared catalyst is stable in structure, high in anti-pollution capacity, excellent in polyphenol wastewater treatment effect and wide in market prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of catalytic materials in the field of polyphenol wastewater treatment, and particularly relates to a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment and a preparation method thereof. BACKGROUND

[0002] In the process of producing a series of chemical products from coal, including coal vaporization, liquefaction, coking, etc., each process will produce corresponding wastewater. These wastewaters are collectively referred to as coal chemical industry wastewater. The composition of such wastewater is complex, and in particular, the concentration of phenolic substances is high, and the toxicity of harmful substances is high. With the rapid development of the coal chemical industry, a large amount of difficult-to-degrade polyphenol wastewater is generated every year, which poses a serious threat to the aquatic environment and human health. The high concentration of organic matter and toxic substances in the wastewater can disrupt the stability of the ecological system and affect the growth and reproduction of aquatic organisms. For humans, the long-term existence of difficult-to-degrade polyphenol wastewater can cause harm to human health through the food chain and trigger related diseases.

[0003] Among the existing technologies for degrading polyphenol wastewater, a Chinese patent with the publication number CN201310085997.0 discloses a method of impregnating active metal on an activated carbon carrier, which solves the technical problems of poor ozone solubility and low degradation rate in the ozone oxidation method. However, the degradation efficiency of phenolic substances is relatively low, and it takes longer to achieve the desired effect compared to general catalyst treatment. A Chinese patent with the publication number CN201911181406.3 discloses a preparation method of a calcined ozone catalyst, which is impregnated in a non-polar reagent for 12-24 hours, then filtered; the filtered ozone catalyst is dried and calcined to obtain a modified ozone catalyst. However, due to the use of spherical catalyst carriers, the spherical catalysts may collide during application, causing catalyst dusting and poor stability, which further affects the efficiency of the catalyst. A Chinese patent with the publication number CN202211542161.4 discloses a preparation method of a multi-channel regular shaped ozone catalytic oxidation catalyst. This method prepares a multi-channel regular shaped ozone catalytic oxidation catalyst through ball milling, mixing, and extrusion technology. The preparation process is simple and easy to operate, the catalyst can be placed in order in the reactor, and water and ozone are mixed to enter the reactor with fixed flow channels. However, the long processing time can cause channel blockage, affecting the mass transfer process of the catalyst during processing, and the catalyst has weak anti-pollution ability.

[0004] The above-mentioned catalysts still have problems such as poor treatment effect, long processing time, unstable catalyst itself, and weak anti-pollution ability during processing of polyphenol wastewater. Therefore, it is still a problem to be solved to invent an ozone catalyst with excellent treatment effect, stable catalyst, and strong anti-pollution ability during processing of polyphenol wastewater. Summary of the Invention

[0005] In response to the deficiencies in the prior art, the present application provides a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment and a preparation method thereof. First, a hydrophilic layer substrate is prepared using Ti3AlC2 as a raw material, and tannic acid and polyethyleneimine are added for synergistic modification, which not only gives the substrate hydrophilicity and positive charge, but also forms a large number of active sites for metal ion coordination, and preloads metal ions on its surface. Then, a functional layer is constructed in a gradient magnetic field, and the gradient magnetic field is used to act secondary on the preloaded metal ions. Through the dual metal site loading and gradient structure design, the reaction activation energy is reduced, the hydroxyl radical generation efficiency is improved, and a dual improvement in the ozone decomposition efficiency and the pollutant mineralization rate is achieved. The hydrophobic layer precursor solution is then drop-coated on its surface to form a hydrophobic layer, and finally immersed in a CaCl2 solution to form an ordered three-dimensional array structure, and freeze-dried to obtain a Janus structure nanosheet array ozone catalyst.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] In the first aspect, the present invention provides a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater, comprising a metal oxide loaded substrate, a hydrophobic layer and calcium ions; the metal oxide loaded substrate comprises a hydrophilic modified substrate and a functional layer, the surface of the hydrophilic modified substrate is loaded with the functional layer, the functional layer is a metal oxide, and the metal oxide is obtained by calcining a metal precursor; the metal precursor comprises a manganese salt and an iron salt; the hydrophilic modified substrate is obtained by modifying a two-dimensional transition metal carbide colloidal substrate with tannic acid and polyethyleneimine, and the two-dimensional transition metal carbide colloidal substrate is obtained by Ti3AlC2 and HF; the hydrophobic layer is made of polytetrafluoroethylene, carbon nanotubes and fluorosilane, and is coated on the surface of the metal oxide loaded substrate.

[0008] In a second aspect, the present application provides a method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater, comprising the following steps:

[0009] S1. Add Ti3AlC2 to HF, stir, centrifuge, and wash the precipitate to obtain a two-dimensional transition metal carbide colloidal substrate. Add tannic acid and polyethyleneimine to the two-dimensional transition metal carbide colloidal substrate, perform a first water bath, and obtain a hydrophilic modified substrate. Add the hydrophilic modified substrate to a metal precursor solution, perform sonication, and obtain a metal precursor-loaded substrate.

[0010] S2. Applying a magnetic field to the metal precursor-loaded substrate, performing a second water bath, adjusting the pH to 10 with sodium hydroxide, and then calcining in air in a muffle furnace to obtain a metal oxide-loaded substrate; dispersing polytetrafluoroethylene and carbon nanotubes in DMF, adding 5% fluorosilane to prepare a hydrophobic layer solution, and drop-coating the solution on the surface of the metal oxide-loaded substrate to form a hydrophobic layer;

[0011] S3. The metal oxide loaded substrate coated with a hydrophobic layer is immersed in a CaCl2 solution for bridging, and then the solvent is removed by freeze-drying to obtain a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater.

[0012] In a feasible implementation scenario, the usage ratio of Ti3AlC2, HF, tannic acid and polyethyleneimine in S1 is (1.8-2) g:50 mL:(0.3-0.7):1; the concentration of HF is 40 wt%-45 wt%.

[0013] In a feasible implementation scenario, the molar ratio of manganese nitrate to iron nitrate in the metal precursor solution of S1 is (2-3): (1-2)

[0014] In a feasible implementation, the centrifugal speed in S1 is 3000-4000 r / min, and the centrifugal time is 5-10 min; the water bath temperature of the first water bath is 50-60° C., and the time is 5-6 h.

[0015] In a feasible implementation scenario, the magnetic field strength in S2 is 0.4-0.6T.

[0016] In a feasible implementation scenario, the temperature of the second water bath in S2 is 55-65°C, and the stirring time is 10-12h; the heating rate of the muffle furnace calcination is 5°C / min, the calcination temperature is 300-360°C, and the calcination time is 2-3h.

[0017] In a feasible implementation scenario, the mass ratio of polytetrafluoroethylene and carbon nanotubes in S2 is (2-4):1.

[0018] In a feasible implementation, the CaCl2 solution in S3 is 0.4-0.6 mol / L, and the soaking time is 20-30 min.

[0019] In a feasible implementation scenario, the freeze-drying temperature in S3 is -50°C and the time is 20 to 24 hours.

[0020] Beneficial technical effects:

[0021] This application constructs a gradient functional layer during the preparation process of the catalyst, with the base being a hydrophilic layer, the middle being a metal oxide loading layer, and the outer layer being a hydrophobic layer, to resolve the conflicting issues between mass transfer and anti-fouling of traditional ozone catalysts. The Mn / Fe bimetallic sites form electronic coupling with the hydrophilic conductive substrate, reducing the reaction activation energy, increasing the efficiency of hydroxyl radical generation, and enhancing the degradation of polyphenol wastewater. Calcium ion crosslinking and freeze-drying realize the transformation of the catalyst from "two-dimensional disordered stacking" to "three-dimensional ordered array". The two synergistically improve the mechanical strength, mass transfer efficiency, and salt resistance stability of the catalyst through structural fixation and pore protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The COD degradation efficiency of the catalysts in Examples 1 to 3 and Comparative Examples 1 to 3 in polyphenol wastewater;

[0023] Figure 2 The phenol reduction efficiency of the catalysts in Examples 1 to 3 and Comparative Examples 1 to 3 in polyphenol wastewater is shown. DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions, and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below with reference to the following examples. However, this should not be construed as limiting the scope of this application to the following examples. Without departing from the above-mentioned method concepts of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0025] In this application, the terms used in this application are for the purpose of describing specific embodiments only and are not intended to be limiting of the application.

[0026] As used in this application, the singular forms "for," "or," "an," "any," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0027] In addition, the terms “first” and “second”, if used, are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

[0028] In the first aspect, the present invention provides a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater, comprising a metal oxide loaded substrate, a hydrophobic layer and calcium ions; the metal oxide loaded substrate comprises a hydrophilic modified substrate and a functional layer, the surface of the hydrophilic modified substrate is loaded with the functional layer, the functional layer is a metal oxide, and the metal oxide is obtained by calcining a metal precursor; the metal precursor comprises a manganese salt and an iron salt; the hydrophilic modified substrate is obtained by modifying a two-dimensional transition metal carbide colloidal substrate with tannic acid and polyethyleneimine, and the two-dimensional transition metal carbide colloidal substrate is obtained by Ti3AlC2 and HF; the hydrophobic layer is made of polytetrafluoroethylene, carbon nanotubes and fluorosilane, and is coated on the surface of the metal oxide loaded substrate.

[0029] In a second aspect, the present application provides a method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater, comprising the following steps:

[0030] S1. Add Ti3AlC2 to HF, stir, centrifuge, and wash the precipitate to obtain a two-dimensional transition metal carbide colloidal substrate. Add tannic acid and polyethyleneimine to the two-dimensional transition metal carbide colloidal substrate, perform a first water bath, and obtain a hydrophilic modified substrate. Add the hydrophilic modified substrate to a metal precursor solution, perform sonication, and obtain a metal precursor-loaded substrate.

[0031] S2. Applying a magnetic field to the metal precursor-loaded substrate, performing a second water bath, adjusting the pH to 10 with sodium hydroxide, and then calcining in air in a muffle furnace to obtain a metal oxide-loaded substrate; dispersing polytetrafluoroethylene and carbon nanotubes in DMF, adding 5% fluorosilane to prepare a hydrophobic layer solution, and drop-coating the solution on the surface of the metal oxide-loaded substrate to form a hydrophobic layer;

[0032] S3. The metal oxide loaded substrate coated with a hydrophobic layer is immersed in a CaCl2 solution for bridging, and then the solvent is removed by freeze-drying to obtain a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater.

[0033] The following will describe in detail a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater and its preparation method provided by the present application in combination with different embodiments.

[0034] Example 1

[0035] A method for preparing a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment comprises the following steps:

[0036] S1. Add 2 g of Ti3AlC2 to 50 mL of 40 wt% HF and stir for 24 h. Centrifuge at 4000 r / min for 5 min. Wash the precipitate to obtain a two-dimensional transition metal carbide colloidal substrate. Add 0.3 g of tannic acid and 1 g of polyethyleneimine to the two-dimensional transition metal carbide colloidal substrate, and stir in a 50°C water bath for 6 h to obtain a hydrophilic modified substrate. Take 1.255 g of manganese nitrate and 1.010 g of ferric nitrate in 50 ml of deionized water to prepare a metal precursor solution, add the hydrophilic modified substrate, and ultrasonicate for 30 min to obtain a metal precursor-loaded substrate.

[0037] S2. Apply a 0.5T magnetic field to the metal precursor-loaded substrate, stir in a 60°C water bath for 12 hours, adjust the pH to 10 with sodium hydroxide, and then calcine in a muffle furnace with air at a heating rate of 5°C / min, a calcination temperature of 300°C, and a calcination time of 2 hours to obtain a metal oxide-loaded substrate; disperse 0.2g of polytetrafluoroethylene and 0.1g of carbon nanotubes in 20mL of DMF, add 0.015g of fluorosilane to prepare a hydrophobic layer solution, and drop-coat the solution on the surface of the metal oxide-loaded substrate to form a hydrophobic layer;

[0038] S3. The metal oxide-supported substrate coated with a hydrophobic layer was immersed in 100 mL of a 0.4 mol / L CaCl2 solution for 30 min for bridging, and then freeze-dried at -50°C for 24 h to remove the solvent to obtain a Janus structure nanosheet array ozone catalyst.

[0039] Example 2

[0040] A method for preparing a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment comprises the following steps:

[0041] S1. Add 1.9 g of Ti3AlC2 to 50 mL of 45 wt% HF and stir for 24 h. Centrifuge at 3000 r / min for 5 min. Wash the precipitate to obtain a two-dimensional transition metal carbide colloidal substrate. Add 0.5 g of tannic acid and 1 g of polyethyleneimine to the two-dimensional transition metal carbide colloidal substrate. Stir in a 55°C water bath for 5.5 h to obtain a hydrophilic modified substrate. Take 1.4354 g of manganese nitrate and 1.2122 g of ferric nitrate in 50 ml of deionized water to prepare a metal precursor solution. Add the hydrophilic modified substrate and sonicate for 30 min to obtain a metal precursor-loaded substrate.

[0042] S2. Apply a 0.4T magnetic field to the metal precursor-loaded substrate, stir in a 65°C water bath for 10 hours, adjust the pH to 10 with sodium hydroxide, and then calcine in air in a muffle furnace at a heating rate of 5°C / min, a calcination temperature of 360°C, and a calcination time of 2 hours to obtain a metal oxide-loaded substrate; disperse 0.3g of polytetrafluoroethylene and 0.1g of carbon nanotubes in 20mL of DMF, add 0.020g of fluorosilane to prepare a hydrophobic layer solution, and drop-coat the solution on the surface of the metal oxide-loaded substrate to form a hydrophobic layer;

[0043] S3. The metal oxide-supported substrate coated with a hydrophobic layer was immersed in 100 mL of a 0.5 mol / L CaCl2 solution for 25 min for bridging, and then freeze-dried at -50°C for 20 h to remove the solvent to obtain a Janus structure nanosheet array ozone catalyst.

[0044] Example 3

[0045] A method for preparing a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment comprises the following steps:

[0046] S1. Add 1.8 g of Ti3AlC2 to 50 mL of 40 wt% HF and stir for 24 h. Centrifuge at 3500 r / min for 10 min. Wash the precipitate to obtain a two-dimensional transition metal carbide colloidal substrate. Add 0.7 g of tannic acid and 1 g of polyethyleneimine to the two-dimensional transition metal carbide colloidal substrate, and stir in a 60°C water bath for 5 h to obtain a hydrophilic modified substrate. Take 1.7224 g of manganese nitrate and 1.6162 g of ferric nitrate in 50 ml of deionized water to prepare a metal precursor solution, add the hydrophilic modified substrate, and ultrasonicate for 30 min to obtain a metal precursor-loaded substrate.

[0047] S2. Apply a 0.6T magnetic field to the metal precursor-loaded substrate, stir in a 55°C water bath for 10 hours, adjust the pH to 10 with sodium hydroxide, and then calcine in air in a muffle furnace at a heating rate of 5°C / min, a calcination temperature of 330°C, and a calcination time of 3 hours to obtain a metal oxide-loaded substrate; disperse 0.4g of polytetrafluoroethylene and 0.1g of carbon nanotubes in 20mL of DMF, add 0.025g of fluorosilane to prepare a hydrophobic layer solution, and drop-coat the solution on the surface of the metal oxide-loaded substrate to form a hydrophobic layer;

[0048] S3. The metal oxide-supported substrate coated with a hydrophobic layer was immersed in 100 mL of a 0.6 mol / L CaCl2 solution for 20 min for bridging, and then freeze-dried at -50°C for 24 h to remove the solvent to obtain a Janus structure nanosheet array ozone catalyst.

[0049] Comparative Example 1

[0050] A method for preparing a Janus structured nanosheet array ozone catalyst for treating polyphenol wastewater, wherein the implementation steps and parameters are the same as those of Example 1, except that only tannic acid is added, and polyethyleneimine is not added.

[0051] Comparative Example 2

[0052] A method for preparing a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment, wherein the implementation steps and parameters are the same as those in Example 1, except that only manganese element is loaded and no iron element is added.

[0053] Comparative Example 3

[0054] A method for preparing a Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment, wherein the implementation steps and parameters are the same as those in Example 1, except that traditional heating drying is used instead of freeze drying.

[0055] Catalyst activity test:

[0056] Weigh 3g of the Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment prepared by Example 1-Example 3 and Comparative Example 1-Comparative Example 3, and load it into a performance evaluation reaction device. The test apparatus is mainly composed of an oxygen tube, an ozone generator, a reaction glass column, and a tail gas recycle device, wherein the middle part of the glass column is provided with a sampling port. 500ml of polyphenol coal chemical industry simulated wastewater is loaded into the glass column, and the total COD is 3010mg / L, and the phenol concentration is 38mg / L, while the ozone generator flow rate is 0.5L / min. Samples are taken at intervals of 1 hour, and the COD concentration at each time point is analyzed by a water quality analyzer, and the phenol concentration is measured by a high performance liquid chromatograph. Record the test results, and after reacting for 4h, wastewater COD, COD removal rate, wastewater phenol concentration, and phenol removal rate are shown in Table 1.

[0057] Table 1 Catalyst activity test results of Examples 1-3 and Comparative Examples 1-3

[0058]

[0059] From Table 1 and Figure 1 、 Figure 2 It can be seen that the Janus structure nanosheet array ozone catalyst for polyphenol wastewater treatment prepared in Examples 1 to 3 of the present invention has a COD removal rate of 85.38% to 90.97% in polyphenol coal chemical simulated wastewater within 4 hours, which is much higher than 46.05% to 57.17% of Comparative Examples 1 to 3, and a phenol removal rate of 84.76% to 98.08%, which is also significantly better than 49.89% to 54.89% of the Comparative Examples. This shows that the catalyst of the present invention has strong anti-fouling ability and excellent effect in polyphenol wastewater treatment.

[0060] Compared with Example 1, in Comparative Example 1, only tannic acid was added without polyethyleneimine, the surface charge density of the substrate was reduced, the synergistic ability of the hydrophilic layer was weakened, the metal particle loading was reduced or unevenly dispersed, resulting in a weakened catalytic effect of the catalyst.

[0061] Compared with Example 1, Comparative Example 2 only loaded manganese element, and the single active component had no synergistic ability, the hydroxyl radical generation efficiency was reduced, and the decomposition rate of organic matter and phenol was reduced, resulting in a weakened catalytic effect of the catalyst.

[0062] Compared with Example 1, in Comparative Example 3, conventional heating and drying was performed, and the nanosheets could not be stacked or arranged in a disordered manner, the array porosity was reduced, the mass transfer resistance was increased, and the ozone utilization rate was reduced, which limited the catalytic performance during the treatment process and led to a weakening of the catalytic effect of the catalyst.

[0063] The above results show and describe the basic principles and main features of this application as well as the advantages of this application.

[0064] Those skilled in the art should understand that the present application is not limited to the above-described embodiments. The above-described embodiments and descriptions are merely illustrative of the principles of the present application. Various changes and improvements may be made to the present application without departing from the spirit and scope of the present application. Such changes and improvements are intended to fall within the scope of the present application. The scope of protection claimed in the present application is defined by the equivalents of the appended claims.

Claims

1. A Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater, characterized in that: It includes a metal oxide-loaded substrate, a hydrophobic layer and calcium ions; the metal oxide-loaded substrate includes a hydrophilic modified substrate and a functional layer; the surface of the hydrophilic modified substrate is loaded with the functional layer, the functional layer is a metal oxide, and the metal oxide is obtained by calcining a metal precursor; the metal precursor includes a manganese salt and an iron salt; the hydrophilic modified substrate is obtained by modifying a two-dimensional transition metal carbide colloid substrate with tannic acid and polyethyleneimine, and the two-dimensional transition metal carbide colloid substrate is obtained by Ti3AlC2 and HF; the hydrophobic layer is made of polytetrafluoroethylene, carbon nanotubes and fluorosilane, and is coated on the surface of the metal oxide-loaded substrate.

2. A method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater as claimed in claim 1, characterized in that: The following steps are involved: S1. Add Ti3AlC2 to HF, stir, centrifuge, and wash the precipitate to obtain a two-dimensional transition metal carbide colloidal substrate. Add tannic acid and polyethyleneimine to the two-dimensional transition metal carbide colloidal substrate, perform a first water bath, and obtain a hydrophilic modified substrate. adding the hydrophilic modified substrate to a metal precursor solution and sonicating to obtain a metal precursor loaded substrate; S2, applying a magnetic field to the metal precursor-supported substrate, placing it in a second water bath, adjusting the pH to 10 with sodium hydroxide, and then calcining it in air in a muffle furnace to obtain a metal oxide-supported substrate; Dispersing polytetrafluoroethylene and carbon nanotubes in DMF, adding 5% fluorosilane to prepare a hydrophobic layer solution, and drop-coating the solution on the surface of the metal oxide-supported substrate to form a hydrophobic layer; S3. Immersing the metal oxide-supported substrate coated with a hydrophobic layer in a CaCl2 solution for bridging, and then removing the solvent through freeze-drying to obtain the Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater.

3. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, wherein: The amount ratio of Ti3AlC2, HF, tannic acid and polyethyleneimine in S1 is (1.8-2) g:50 mL:(0.3-0.7):1; the concentration of HF is 40wt%-45wt%.

4. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, wherein: The molar ratio of manganese nitrate to iron nitrate in the metal precursor solution S1 is (2-3):(1-2).

5. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, characterized in that: The centrifugal speed in S1 is 3000-4000 r / min, and the centrifugal time is 5-10 min; the water bath temperature of the first water bath is 50-60° C., and the time is 5-6 h.

6. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, characterized in that: The magnetic field strength of S2 is 0.4-0.6T.

7. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, characterized in that: S2 The temperature of the second water bath is 55-65°C, and the stirring time is 10-12h; the heating rate of the muffle furnace calcination is 5°C / min, the calcination temperature is 300-360°C, and the calcination time is 2-3h.

8. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, characterized in that: The mass ratio of polytetrafluoroethylene and carbon nanotubes in S2 is (2-4):

1.

9. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, characterized in that: The CaCl2 solution in S3 is 0.4-0.6 mol / L, and the soaking time is 20-30 min.

10. The method for preparing a Janus structure nanosheet array ozone catalyst for treating polyphenol wastewater according to claim 2, characterized in that: The freeze drying temperature in S3 is -50°C and the time is 20 to 24 hours.

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