Thiophanate-methyl wastewater treatment process

Abstract

The invention discloses a thiophanate-methyl wastewater treatment process, and belongs to the technical field of pesticide wastewater treatment. The thiophanate-methyl wastewater treatment process comprises the following steps: S1, carrying out catalytic wet oxidation reaction on thiophanate-methyl production wastewater to obtain a treatment solution I; s2, a modified catalyst is added into the treatment liquid I for photocatalytic treatment, and treatment liquid II is obtained; and S3, performing membrane distillation treatment on the treatment liquid II to obtain a treatment liquid III, thereby completing the treatment. N, S and F atoms on a carbon substrate of the modified catalyst are directly connected with Ti atoms, and compared with a common porous material, the modified catalyst has higher photoreaction efficiency. Besides, N, S and F atoms on the carbon material can serve as active sites, the carbon skeleton is stable in chemical property and large in specific surface area and has more active sites, the catalytic efficiency of the modified catalyst is improved, and the COD removal rate reaches 97.6% or above.

Description

Technical Field

[0001] The present invention relates to the field of pesticide wastewater treatment, in particular to a thiophanate-methyl wastewater treatment process. Background Art

[0002] Thiophanate-methyl, also known as thiophanate-methyl, is chemically known as 1,2-bis(3-methoxycarbonyl-2-thioureido)benzene. It is a highly effective, low-toxic, systemic, broad-spectrum fungicide. It is widely used for disease control in crops such as vegetables, fruits, cotton, sugar beets, wheat, and rice. It can also be used to prevent mildew and decay in textiles, paper, and leather, and preserve fruit, and has promising market prospects.

[0003] The synthesis route for thiophanate-methyl primarily uses methyl chloroformate and sodium thiocyanate as raw materials, using N,N-dimethylaniline as a catalyst. Methyl isothiocyanate is first synthesized, and then condensed with o-phenylenediamine. Production wastewater primarily originates from the synthesis of methyl isothiocyanate, product washing, and solvent recovery processes. This wastewater is light green in color, and its primary organic compounds are o-phenylenediamine, ethanol, acetic acid, ethyl acetate, and thiophanate-methyl. It exhibits high COD, high salinity, and significant toxicity, making it highly contaminated, hazardous, and difficult to biodegrade.

[0004] Currently, little research has been conducted on methods for treating thiophanate-methyl production wastewater. Generally speaking, incineration is a more suitable method for treating this high-concentration, high-salinity, and highly toxic organic pesticide wastewater. However, incineration methods require complex equipment, require significant investment, and, in most cases, consume significant energy. Patent CN118255487A provides a photocatalytic treatment method for thiophanate-methyl production wastewater. This patent pre-treats thiophanate-methyl production wastewater with titanium dioxide and ultraviolet light, improving its biodegradability and facilitating subsequent degradation of organic pollutants in the wastewater. Following the pre-treatment, the wastewater is precipitated three times and then post-treated with a combination of carbon powder and iron powder, allowing for the presence of microelectrolysis in the system to degrade organic matter. However, titanium dioxide suffers from the disadvantages of easy electron-hole recombination and low quantum efficiency, which severely impacts its effectiveness, limiting its photocatalytic performance and resulting in poor COD removal. Summary of the Invention

[0005] The invention provides a thiophanate-methyl wastewater treatment process, which can solve the problems in the prior art of easy electron-hole recombination and low quantum efficiency of titanium dioxide and poor COD removal rate.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A thiophanate-methyl wastewater treatment process comprises the following steps:

[0008] S1: catalytic wet oxidation reaction of thiophanate-methyl production wastewater to obtain treated liquid I;

[0009] S2: adding a modified catalyst to the treatment liquid I for photocatalytic treatment to obtain a treatment liquid II, wherein the modified catalyst is obtained by composite hydrolysis of a nitrogen-sulfur-fluorine co-doped porous carbon material and a titanium source, the nitrogen-sulfur-fluorine co-doped porous carbon material is obtained by carbonization of a nitrogen-sulfur-fluorine doped metal organic framework, and the ligands of the nitrogen-sulfur-fluorine doped metal organic framework include 2-methylimidazole and 2-mercapto-5-fluorobenzimidazole;

[0010] S3: The treated liquid II is treated by membrane distillation to obtain treated liquid III, thus completing the treatment.

[0011] Furthermore, in step S1, the oxidant of the catalytic wet oxidation reaction is oxygen, the flow rate of oxygen is 40-45 L / h; the temperature is 200-250°C, the pressure is 2-4 MPa, and the time is 2-3 hours.

[0012] Furthermore, in step S1, the catalyst for the catalytic wet oxidation reaction is CuSO4·5H2O, and the usage ratio of CuSO4·5H2O to methyl thiophanate production wastewater is 2-4g:1L.

[0013] Furthermore, in step S2, the ratio of the mass of the treatment liquid I to the power of the ultraviolet lamp is 1000g:100W; the mass of the modified catalyst is 0.3-0.5% of the mass of the treatment liquid I.

[0014] Furthermore, in step S2, the photocatalytic time is 1-2 hours, and the photocatalytic wavelength is 300 nm.

[0015] Furthermore, in step S3, the membrane is a hydrophobic membrane, and the hydrophobic membrane material is any one of polytetrafluoroethylene, polyvinylidene fluoride and polypropylene.

[0016] Furthermore, in step S3, the porosity of the membrane is 60-95%, the pore size is 1-10 μm, and the membrane thickness is 0.05-0.25 mm.

[0017] Furthermore, the preparation method of the modified catalyst is:

[0018] A1: Add zinc salt, 2-methylimidazole, and 2-mercapto-5-fluorobenzimidazole to methanol to obtain a mixed solution, stir at room temperature for 20-24 hours, and then centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-fluorine-doped metal-organic framework.

[0019] In the above steps, zinc salt is used as metal salt, 2-methylimidazole is used as organic ligand, and 2-mercapto-5-fluorobenzimidazole is used as doping ligand to prepare a nitrogen-sulfur-fluorine doped metal organic framework.

[0020] A2: Add the nitrogen, sulfur and fluorine co-doped metal organic framework into a crucible, place it in a tube furnace, and calcine it for 2-4 hours under an inert atmosphere. After cooling to room temperature, collect it to obtain a nitrogen, sulfur and fluorine co-doped porous carbon material;

[0021] In the above steps, nitrogen, sulfur and fluorine doped metal organic frameworks are carbonized to obtain nitrogen, sulfur and fluorine co-doped porous carbon materials containing a mesoporous structure.

[0022] A3: Add nitrogen, sulfur and fluorine co-doped porous carbon material to anhydrous ethanol, mix ultrasonically, and stir at room temperature for 20-30 minutes to obtain solution A. Then add ammonia water, and then add isopropyl titanate to solution A, and stir at room temperature for 30-60 minutes to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, and hydrothermally react at 120°C for 9-13 hours. Then, centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcine for 2-4 hours under an inert atmosphere to obtain a modified catalyst.

[0023] In the above steps, the nitrogen, sulfur and fluorine co-doped porous carbon material is hydrolyzed and dried with the titanium source and then calcined to form a modified catalyst. In this process, N, S and F can directly connect with Ti, thereby quickly transferring photogenerated electrons and inhibiting electron-hole recombination. The carbon substrate containing nitrogen, sulfur and fluorine can quickly transfer photogenerated electrons, and the nitrogen, sulfur and fluorine atoms on the carbon can also act as electron acceptors to react with O2 adsorbed on the surface to form O2 - , which can make full use of photogenerated electrons, avoid their recombination on the carbon substrate, and improve the efficiency of photocatalysis.

[0024] Furthermore, in step A1, the zinc salt is any one of zinc nitrate hexahydrate, zinc acetate or zinc sulfate; the molar ratio of the zinc salt, 2-methylimidazole and 2-mercapto-5-fluorobenzimidazole is 1:1:(1-3); and the concentration of the zinc salt in the mixed solution is 4 g / L.

[0025] Furthermore, in step A2, the temperature of the tubular furnace calcination is 900-1000° C., and the heating rate is 2-4° C. / min.

[0026] Furthermore, in step A3, the temperature of the tubular furnace calcination is 450-500° C., and the heating rate is 2-4° C. / min.

[0027] Furthermore, in step A2 and step A3, the inert atmosphere is any one of nitrogen, argon and helium.

[0028] Furthermore, in step A3, the usage ratio of nitrogen, sulfur and fluorine co-doped porous carbon material, anhydrous ethanol, ammonia water and isopropyl titanate is 0.1-0.2 g: 200-400 mL: 20-50 mL: 5-10 mL.

[0029] Beneficial effects of the present invention:

[0030] The present invention adds a modified catalyst during the process of treating thiophanate-methyl wastewater. The modified catalyst is obtained by calcining a nitrogen, sulfur, and fluorine co-doped porous carbon material and a titanium source after composite hydrolysis, drying, and subsequent calcination. The N, S, and F atoms on the carbon substrate are directly connected to the Ti atoms, and have a higher photoreaction efficiency than ordinary porous materials. In addition, the N, S, and F atoms on the carbon material can serve as active sites, and the carbon skeleton has stable chemical properties and a large specific surface area with more active sites. Combining the above features, the photocatalytic efficiency of the modified catalyst is improved, so that it can also achieve a higher COD removal rate in a shorter time. DETAILED DESCRIPTION

[0031] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0032] The wastewater generated in the thiophanate-methyl process of the present invention is light green in color, and the main organic matter is o-phenylenediamine, ethanol, acetic acid, ethyl acetate and thiophanate-methyl, etc. According to the measurement, the pH of the wastewater is 2-3, and the COD is 19000 mg / L.

[0033] Example 1

[0034] A thiophanate-methyl wastewater treatment process comprises the following steps:

[0035] S1: 1L of thiophanate-methyl production wastewater and 2g of CuSO4·5H2O were added to a catalytic wet oxidation reactor, heated to 200°C and pressured to 2 MPa. Oxygen was introduced and then cooled for 2 hours at an oxygen flow rate of 40 L / h to obtain treated solution I.

[0036] S2: adding the modified catalyst to the treatment solution I for photocatalytic treatment at a wavelength of 300 nm for 1 hour to obtain treatment solution II, wherein the ratio of the mass of treatment solution I to the power of the UV lamp is 1000 g:100 W; the mass of the modified catalyst is 0.3% of the mass of treatment solution I;

[0037] S3: The treated liquid II is treated by three-stage membrane distillation to obtain treated liquid III, thus completing the treatment. The membrane distillation system uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.4 μm, a porosity of more than 80%, and a membrane thickness of 0.1 mm.

[0038] The preparation method of the modified catalyst is:

[0039] A1: Add 1.8 g of zinc acetate, 0.82 g of 2-methylimidazole, and 1.7 g of 2-mercapto-5-fluorobenzimidazole to 450 mL of methanol to obtain a mixed solution. Stir the solution at room temperature for 20 h. Centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-fluorine-doped metal-organic framework.

[0040] A2: Add the nitrogen-sulfur-fluorine co-doped metal organic framework into a crucible, place it in a tube furnace, and calcine it at 900°C for 2 hours under a nitrogen atmosphere at a heating rate of 2°C / min. After cooling to room temperature, collect it to obtain a nitrogen-sulfur-fluorine co-doped porous carbon material;

[0041] A3: Add 0.1 g of nitrogen, sulfur and fluorine co-doped porous carbon material to 200 mL of anhydrous ethanol, mix ultrasonically, and stir at room temperature for 20 min to obtain solution A. Then add 20 mL of ammonia water, and then add 5 mL of isopropyl titanate to solution A, and stir at room temperature for 30 min to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, and hydrothermally react at 120°C for 9 h. Then, centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcine at 450°C for 2 h in a nitrogen atmosphere with a heating rate of 2°C / min to obtain a modified catalyst.

[0042] The COD removal rate of this embodiment was measured to be 97.6%.

[0043] Example 2

[0044] A thiophanate-methyl wastewater treatment process comprises the following steps:

[0045] S1: 1L of thiophanate-methyl production wastewater and 3g of CuSO4·5H2O were added to a catalytic wet oxidation reactor, heated to 250°C and pressure of 4 MPa, and then cooled after 3 hours after oxygen was introduced at an oxygen flow rate of 45 L / h to obtain treated solution I;

[0046] S2: Add the modified catalyst to the treatment liquid I for photocatalytic treatment at a wavelength of 300nm for 2h to obtain treatment liquid II. The ratio of the mass of treatment liquid I to the power of the ultraviolet lamp is 1000g:100W; the mass of the modified catalyst is 0.35% of the mass of treatment liquid I.

[0047] S3: The treated liquid II is treated by three-stage membrane distillation to obtain treated liquid III, thus completing the treatment. The membrane distillation system uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.4 μm, a porosity of more than 80%, and a membrane thickness of 0.1 mm.

[0048] The preparation method of the modified catalyst is:

[0049] A1: Add 1.8 g of zinc acetate, 0.82 g of 2-methylimidazole, and 2.5 g of 2-mercapto-5-fluorobenzimidazole to 450 mL of methanol to obtain a mixed solution. Stir the solution at room temperature for 24 h, then centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-fluorine-doped metal-organic framework.

[0050] A2: Add the nitrogen-sulfur-fluorine co-doped metal-organic framework into a crucible, place it in a tube furnace, and calcine it at 1000°C for 4 hours under a nitrogen atmosphere at a heating rate of 4°C / min. After cooling to room temperature, collect it to obtain a nitrogen-sulfur-fluorine co-doped porous carbon material;

[0051] A3: Add 0.15 g of nitrogen, sulfur and fluorine co-doped porous carbon material to 300 mL of anhydrous ethanol, mix ultrasonically, and stir at room temperature for 30 min to obtain solution A. Then add 35 mL of ammonia water, and then add 7 mL of isopropyl titanate to solution A, and stir at room temperature for 60 min to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, hydrothermally react at 120°C for 13 h, and then centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcine at 500°C for 4 h in a nitrogen atmosphere with a heating rate of 4°C / min to obtain a modified catalyst.

[0052] The COD removal rate of this embodiment was measured to be 97.8%.

[0053] Example 3

[0054] A thiophanate-methyl wastewater treatment process comprises the following steps:

[0055] S1: 1L of thiophanate-methyl production wastewater and 4g of CuSO4·5H2O were added to a catalytic wet oxidation reactor, heated to 250°C and pressure of 4 MPa, and then cooled after 3 hours after oxygen was introduced at an oxygen flow rate of 45L / h to obtain treated solution I;

[0056] S2: Add the modified catalyst to the treatment liquid I for photocatalytic treatment at a wavelength of 300nm for 1-2h to obtain treatment liquid II. The ratio of the mass of treatment liquid I to the power of the ultraviolet lamp is 1000g:100W; the mass of the modified catalyst is 0.4% of the mass of treatment liquid I.

[0057] S3: The treated liquid II is treated by three-stage membrane distillation to obtain treated liquid III, thus completing the treatment. The membrane distillation system uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.4 μm, a porosity of more than 80%, and a membrane thickness of 0.1 mm.

[0058] The preparation method of the modified catalyst is:

[0059] A1: Add 1.8 g of zinc acetate, 0.82 g of 2-methylimidazole, and 5 g of 2-mercapto-5-fluorobenzimidazole to 450 mL of methanol to obtain a mixed solution. Stir the solution at room temperature for 24 h, then centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-fluorine-doped metal-organic framework.

[0060] A2: Add the nitrogen-sulfur-fluorine co-doped metal-organic framework into a crucible, place it in a tube furnace, and calcine it at 1000°C for 4 hours under a nitrogen atmosphere at a heating rate of 4°C / min. After cooling to room temperature, collect it to obtain a nitrogen-sulfur-fluorine co-doped porous carbon material;

[0061] A3: Add 0.2 g of nitrogen, sulfur and fluorine co-doped porous carbon material to 400 mL of anhydrous ethanol, mix ultrasonically, and stir at room temperature for 30 min to obtain solution A. Then add 50 mL of ammonia water, and then add 10 mL of isopropyl titanate to solution A, and stir at room temperature for 60 min to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, and hydrothermally react at 120°C for 13 h. Then, centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcined at 500°C in a nitrogen atmosphere for 4 h with a heating rate of 4°C / min to obtain a modified catalyst.

[0062] The COD removal rate of this embodiment was measured to be 98.1%.

[0063] Example 4

[0064] Compared with Example 3, this embodiment is different in that:

[0065] The mass of the modified catalyst is 0.45% of the mass of the treatment liquid I. The remaining raw materials and steps are the same as those in Example 3.

[0066] The COD removal rate of this embodiment was measured to be 98.3%.

[0067] Example 5

[0068] Compared with Example 3, this embodiment is different in that:

[0069] The mass of the modified catalyst is 0.5% of the mass of the treatment liquid I. The remaining raw materials and steps are the same as those in Example 3.

[0070] The COD removal rate of this embodiment was measured to be 98.7%.

[0071] Comparative Example 1

[0072] This comparative example is different from Example 1 in that 2-mercapto-5-fluorobenzimidazole is replaced by 2-mercaptoimidazole. The specific steps are as follows:

[0073] The preparation method of the modified catalyst is:

[0074] A1: Add 1.8 g of zinc acetate, 0.82 g of 2-methylimidazole, and 1 g of 2-mercaptoimidazole to 450 mL of methanol to obtain a mixed solution. Stir the solution at room temperature for 20 h. Centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-doped metal-organic framework.

[0075] A2: Add the nitrogen-sulfur co-doped metal organic framework into a crucible, place it in a tube furnace, and calcine it at 900°C for 2 hours under a nitrogen atmosphere at a heating rate of 2°C / min. After cooling to room temperature, collect it to obtain nitrogen-sulfur-fluorine co-doped porous carbon material;

[0076] A3: Add 0.1 g of nitrogen-sulfur co-doped porous carbon material to 200 mL of anhydrous ethanol, mix ultrasonically, and stir at room temperature for 20 min to obtain solution A. Then add 20 mL of ammonia water, and then add 5 mL of isopropyl titanate to solution A, and stir at room temperature for 30 min to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, hydrothermally react at 120°C for 9 h, and then centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcine at 450°C under a nitrogen atmosphere for 2 h with a heating rate of 2°C / min to obtain a modified catalyst.

[0077] The remaining materials and steps are the same as in Example 1.

[0078] The COD removal rate of this embodiment was measured to be 97.3%.

[0079] Comparative Example 2

[0080] Compared with Example 1, this comparative example is different in that 2-mercapto-5-fluorobenzimidazole is removed, and the specific steps are as follows:

[0081] The preparation method of the modified catalyst is:

[0082] A1: Add 1.8 g of zinc acetate and 0.82 g of 2-methylimidazole to 450 mL of methanol to obtain a mixed solution. Stir the solution at room temperature for 20 h. Centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-fluorine-doped metal-organic framework.

[0083] A2: Add the nitrogen-sulfur-fluorine co-doped metal organic framework into a crucible, place it in a tube furnace, and calcine it at 900°C for 2 hours under a nitrogen atmosphere at a heating rate of 2°C / min. After cooling to room temperature, collect it to obtain a nitrogen-sulfur-fluorine co-doped porous carbon material;

[0084] A3: Add 0.1 g of nitrogen, sulfur and fluorine co-doped porous carbon material to 200 mL of anhydrous ethanol, mix ultrasonically, and stir at room temperature for 20 min to obtain solution A. Then add 20 mL of ammonia water, and then add 5 mL of isopropyl titanate to solution A, and stir at room temperature for 30 min to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, and hydrothermally react at 120°C for 9 h. Then, centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcine at 450°C for 2 h in a nitrogen atmosphere with a heating rate of 2°C / min to obtain a modified catalyst.

[0085] The COD removal rate of this embodiment was measured to be 96.8%.

[0086] Comparative Example 3

[0087] Compared with Example 1, this comparative example is different in that:

[0088] The modified catalyst was replaced with titanium dioxide, and the remaining raw materials and steps were the same as in Example 1.

[0089] After measurement, the COD removal rate of this embodiment is 94.1%.

[0090] Comparative Example 4

[0091] Compared with Example 1, this comparative example is different in that:

[0092] The mass of the modified catalyst is 0.25% of the mass of the treatment liquid I. The remaining raw materials and steps are the same as those in Example 1.

[0093] The COD removal rate of this embodiment was measured to be 97.2%.

[0094] Comparative Example 5

[0095] Compared with Example 3, this comparative example is different in that:

[0096] The mass of the modified catalyst is 0.55% of the mass of the treatment liquid I. The remaining raw materials and steps are the same as those in Example 3.

[0097] The COD removal rate of this embodiment was measured to be 98.2%.

[0098] By comparing the test results of Examples 1 to 5 with Comparative Examples 1 to 5, it can be seen that the COD removal rates of the examples are higher than those of the comparative examples. Comparative Example 1 does not contain fluorine elements, and its removal rate is lower than that of Example 1, indicating that F atoms can act as active sites and improve catalytic efficiency; Comparative Example 2 does not contain sulfur elements and fluorine elements, and its removal rate is lower than that of Example 1, indicating that sulfur atoms can also act as active sites and improve catalytic efficiency; in Comparative Example 3, titanium dioxide is directly used as a catalyst, and its stability is reduced, the active sites are reduced, and the catalytic efficiency is reduced; the amount of catalyst used in Comparative Example 4 is too little, and the COD removal rate is lower than that of Example 1; the amount of catalyst used in Comparative Example 5 is too much, and the COD removal rate is lower than that of Example 3, indicating that too much or too little catalyst is not conducive to improving catalytic performance. The amount of the catalyst of the present invention is the optimal amount. Excessive catalyst may cause blocking and overlapping between particles, reduce the effective surface area of ​​the catalyst, and affect light penetration and the absorption of light by the catalyst.

[0099] The above disclosures are only a few specific embodiments of the present invention. However, the embodiments of the present invention are not limited thereto. Any changes that can be conceived by those skilled in the art should fall within the scope of protection of the present invention.

Claims

1. A thiophanate-methyl wastewater treatment process, characterized in that, The following steps are involved: S1: catalytic wet oxidation reaction of thiophanate-methyl production wastewater to obtain treated liquid I; S2: adding a modified catalyst to the treatment liquid I for photocatalytic treatment to obtain a treatment liquid II, wherein the modified catalyst is obtained by composite hydrolysis of a nitrogen-sulfur-fluorine co-doped porous carbon material and a titanium source, the nitrogen-sulfur-fluorine co-doped porous carbon material is obtained by carbonization of a nitrogen-sulfur-fluorine doped metal organic framework, and the ligands of the nitrogen-sulfur-fluorine doped metal organic framework include 2-methylimidazole and 2-mercapto-5-fluorobenzimidazole; S3: The treated liquid II is treated by membrane distillation to obtain treated liquid III, thus completing the treatment.

2. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step S1, the oxidant of the catalytic wet oxidation reaction is oxygen, the flow rate of oxygen is 40-45 L / h; the temperature is 200-250° C., the pressure is 2-4 MPa, and the time is 2-3 h.

3. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step S1, the catalyst for the catalytic wet oxidation reaction is CuSO4·5H2O, and the usage ratio of CuSO4·5H2O to methyl thiophanate production wastewater is 2-4g:1L.

4. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step S2, the ratio of the mass of the treatment liquid I to the power of the ultraviolet lamp is 1000g:100W; the mass of the modified catalyst is 0.3-0.5% of the mass of the treatment liquid I.

5. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step S2, the photocatalytic time is 1-2 hours, and the photocatalytic wavelength is 300 nm.

6. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step S3, the membrane is a hydrophobic membrane, and the hydrophobic membrane material is any one of polytetrafluoroethylene, polyvinylidene fluoride and polypropylene; the porosity of the membrane is 60-95%, the pore size is 1-10 μm, and the membrane thickness is 0.05-0.25 mm.

7. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, The preparation method of the modified catalyst is: A1: Add zinc salt, 2-methylimidazole, and 2-mercapto-5-fluorobenzimidazole to methanol to obtain a mixed solution, stir at room temperature for 20-24 hours, and then centrifuge, wash, and dry the solution to obtain a nitrogen-sulfur-fluorine-doped metal-organic framework. A2: Add the nitrogen, sulfur and fluorine co-doped metal organic framework into a crucible, place it in a tube furnace, and calcine it for 2-4 hours under an inert atmosphere. After cooling to room temperature, collect it to obtain a nitrogen, sulfur and fluorine co-doped porous carbon material; A3: Add nitrogen, sulfur and fluorine co-doped porous carbon material to anhydrous ethanol, mix ultrasonically, and stir at room temperature for 20-30 minutes to obtain solution A. Then add ammonia water, and then add isopropyl titanate to solution A, and stir at room temperature for 30-60 minutes to obtain solution B. Transfer the mixed solution B to a polytetrafluoroethylene reactor liner, and then place the polytetrafluoroethylene reactor liner into a high-pressure reactor, and hydrothermally react at 120°C for 9-13 hours. Then, centrifuge, wash, and dry the solution to obtain powder C. Transfer the powder C to a crucible and place it in a tubular furnace. Calcine for 2-4 hours under an inert atmosphere to obtain a modified catalyst.

8. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step A1, the zinc salt is any one of zinc nitrate hexahydrate, zinc acetate or zinc sulfate; the molar ratio of the zinc salt, 2-methylimidazole and 2-mercapto-5-fluorobenzimidazole is 1:1:(1-3); and the concentration of the zinc salt in the mixed solution is 4 g / L.

9. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that, In step A2, the temperature of the tubular furnace calcination is 900-1000° C., and the heating rate is 2-4° C. / min; in step A3, the temperature of the tubular furnace calcination is 450-500° C., and the heating rate is 2-4° C. / min.

10. A thiophanate-methyl wastewater treatment process according to claim 1, characterized in that: In step A2 and step A3, the inert atmosphere is any one of nitrogen, argon and helium; in step A3, the amount ratio of nitrogen, sulfur and fluorine co-doped porous carbon material, anhydrous ethanol, ammonia water and isopropyl titanate is 0.1-0.2g:200-400mL:20-50mL:5-10mL.