Thiophanate-methyl production wastewater treatment method

Abstract

The invention discloses a thiophanate-methyl production wastewater treatment method, and belongs to the technical field of pesticide wastewater treatment.The thiophanate-methyl production wastewater treatment method comprises the following steps that S1, copper sulfate pentahydrate is added into thiophanate-methyl production wastewater, then the mixture is introduced into a catalytic wet oxidation kettle for a reaction, and treatment liquid I is obtained; s2, adding a modified catalyst into the treating fluid I, and performing photocatalysis to obtain treating fluid II; and S3, carrying out three-stage membrane distillation treatment on the treatment liquid II to obtain a treatment liquid III, thereby completing the treatment. According to the method, the COD and ammonia nitrogen concentration in the production wastewater is remarkably reduced, and the COD and ammonia nitrogen removal rate is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of pesticide wastewater treatment, and specifically relates to a method for treating thiophanate-methyl production wastewater. Background Art

[0002] Methyl thiophanate, also known as thiophanate-methyl (abbreviated as thiophanate-methyl), is a broad-spectrum systemic low-toxic fungicide with systemic, preventive and therapeutic effects. Methyl thiophanate has therapeutic and preventive effects on a variety of diseases, so it is widely used in the prevention and control of diseases of fruit trees, vegetables, flowers, wheat and other crops.

[0003] At present, the synthesis route of methyl thiophanate mainly uses methyl chloroformate and sodium thiocyanide as raw materials, N,N-dimethylaniline as catalyst, first synthesizes methyl isothiocyanate, and then condenses with o-phenylenediamine. Its production wastewater mainly comes from the synthesis of methyl isothiocyanate, product washing and solvent recovery. The wastewater mainly contains organic compounds such as N,N-dimethylaniline, thiocarbamate, methyl thiophanate and its isomers. The pH value of the wastewater is about 3-5, the COD concentration is as high as 20000-40000 mg / L, and the sodium chloride content is about 20% (based on the mass of the wastewater). The wastewater has the characteristics of strong odor, high COD, high salinity, high toxicity, etc., and belongs to high-concentration difficult-to-degrade pesticide wastewater.

[0004] Nowadays, methyl thiophanate wastewater is generally treated by incineration, but the equipment used in the incineration method is complex and expensive. The patent with patent announcement number CN105906100B discloses a method for treating methyl thiophanate production wastewater, including the following steps: macroporous resin adsorption treatment, catalytic wet oxidation, photocatalysis and membrane distillation, etc., wherein the catalytic wet oxidation uses a supported catalyst or a soluble transition metal salt, the carrier of the supported catalyst is titanium dioxide, the active ingredient is at least one of ruthenium, rhodium and palladium, and the soluble transition metal salt is at least one of iron, copper, cobalt, nickel and manganese salt; when performing photocatalysis, the catalyst used is at least one of titanium dioxide, zinc oxide, tin oxide, zirconium dioxide and cadmium sulfide, but the removal rate of COD and ammonia nitrogen in methyl thiophanate wastewater treated by this treatment method is still low. Summary of the invention

[0005] In order to solve the problem that the removal rates of COD and ammonia nitrogen in methyl thiophanate wastewater after treatment by the prior art are still low, the object of the present invention is to provide a method for treating methyl thiophanate production wastewater.

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

[0007] A method for treating thiophanate-methyl production wastewater comprises the following steps:

[0008] Step S1: adding copper sulfate pentahydrate to methyl thiophanate production wastewater, and then passing it into a catalytic wet oxidation kettle for reaction to obtain a treated solution I;

[0009] Among them, the dosage ratio of methyl thiophanate production wastewater to copper sulfate pentahydrate is 1L:2-5g.

[0010] In this step, the copper ions in copper sulfate pentahydrate can undergo a complex reaction or a redox reaction with the organic matter in the wastewater, thereby changing the structure and properties of the organic matter and making it easier to be oxidized and degraded.

[0011] Step S2: adding a modified catalyst to the treatment liquid I to perform photocatalysis to obtain a treatment liquid II;

[0012] The dosage ratio of the treatment liquid I to the modified catalyst is 1L:1-2g.

[0013] Step S3: The treated liquid II is treated by three-stage membrane distillation to obtain the treated liquid III, thus completing the treatment.

[0014] Furthermore, before step S1, 30 wt % sodium hydroxide aqueous solution is added to the wastewater to adjust the pH of the wastewater to 7-8.

[0015] Furthermore, in step S1, the oxidant for the catalytic wet oxidation reaction is air or oxygen, and the flow rate of the air or oxygen is 40 L / h.

[0016] Furthermore, in step S1, the temperature of the catalytic wet oxidation reaction is 210-260°C; the reaction pressure is 2-6MPa; and the reaction time is 2-2.5h.

[0017] Further, in step S2, the preparation steps of the modified catalyst are:

[0018] Step A1: Add activated carbon to 1 g / L nanosilver-surfactant complex solution, stir at 160-200 r / min for 3-4 hours, then wash with water and dry to obtain modified activated carbon.

[0019] The dosage ratio of 1g / L nanosilver-surfactant complex solution to activated carbon is 100-140mL:10g.

[0020] Step A2: Anhydrous ethanol, tetrabutyl titanate and glacial acetic acid are mixed to obtain a mixed solution A; modified activated carbon is added to the mixed solution A, and then an ethanol aqueous solution with a volume fraction of 80% is added to obtain a gel; the gel is placed in a reactor for aging for 8 hours, and then hydrothermally reacted at 120-130° C. for 12 hours. After cooling to room temperature, the gel is taken out and washed with deionized water for 3 times, filtered, dried at 90° C. for 12 hours, and ground to obtain a modified catalyst.

[0021] The volume ratio of anhydrous ethanol, tetrabutyl titanate and glacial acetic acid in the mixed liquid A is 2-2.5:1-2:0.15-0.25; the dosage ratio of the mixed liquid A, modified activated carbon and ethanol aqueous solution is 30-35mL:2.5-3g:13-18mL.

[0022] Furthermore, the preparation method of the nanosilver-surfactant complex solution is:

[0023] 0.06 mol / L (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide aqueous solution, 0.01 mol / L silver nitrate aqueous solution, and 0.5 mol / L sodium borohydride aqueous solution were stirred evenly and reacted at room temperature for 8 hours to obtain a nanosilver-surfactant complex solution.

[0024] The volume ratio of the (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide aqueous solution, the silver nitrate aqueous solution and the sodium borohydride aqueous solution is 5:5:1.

[0025] In the above steps, silver nitrate is ionized into silver ions in water, and sodium borohydride, as a strong reducing agent, can reduce the silver ions to silver atoms, thereby forming nano silver particles. The mercapto group in (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide has a strong interaction with silver, thereby stabilizing the nano silver particles and preventing them from agglomerating, which helps to form a uniformly dispersed nano silver-surfactant complex solution.

[0026] Furthermore, in step S2, the photocatalytic time is 0.5-1h; the wavelength of the photocatalytic is 400nm.

[0027] Furthermore, in step S3, the three-stage membrane distillation system uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.1-1 μm, a porosity of 70-90%, and a membrane thickness of 0.1-0.25 mm.

[0028] Beneficial effects of the present invention:

[0029] 1. The present invention forms a modified catalyst by compounding modified activated carbon and nano titanium dioxide, and the modified activated carbon contains nano silver-surfactant complex. The nano titanium dioxide is compounded with the adsorptive carrier modified activated carbon, which not only greatly improves the dispersibility of nano particles, increases the contact area with the target pollutant, but also realizes the immobilization of nano particles, improves the photocatalytic efficiency, and reduces the COD value and ammonia nitrogen concentration in the methyl-thiophanate production wastewater. In addition, the silver nano particles in the nano silver-surfactant complex have a plasma resonance effect under visible light irradiation, and the photocatalytic activity of the modified catalyst can be improved along with the transfer of "hot" electrons when the silver nano particles and nano titanium dioxide are compounded, which improves the catalytic efficiency, and further reduces the COD value and ammonia nitrogen concentration in the methyl-thiophanate production wastewater.

[0030] 2. The nanosilver-surfactant complex contains quaternary ammonium groups, which will make the modified catalyst carry a positive charge. - , the modified catalyst with positive charge can efficiently adsorb SCN under electrostatic action - , thereby reducing the organic matter in the wastewater and reducing the COD value and ammonia nitrogen concentration in the methyl thiophanate production wastewater. DETAILED DESCRIPTION

[0031] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] The wastewater of methyl thiophanate of the present invention mainly contains organic compounds such as N, N-dimethylaniline, thioisoester, methyl thiocyanoformate, sulfide, etc. After measurement, the production wastewater has a pH of 2-3, a COD of 19000-20000 mg / L, and an ammonia nitrogen content of 125-136 mg / L.

[0033] Preparation Example 1

[0034] The preparation method of the nanosilver-surfactant complex solution in this preparation example is:

[0035] 5 mL of 0.06 mol / L (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide aqueous solution, 5 mL of 0.01 mol / L silver nitrate aqueous solution, and 1 mL of 0.5 mol / L sodium borohydride aqueous solution were stirred evenly and reacted at room temperature for 8 hours to obtain a nanosilver-surfactant complex solution.

[0036] Preparation Example 2

[0037] The preparation method of the nanosilver-surfactant complex solution in this preparation example is:

[0038] 5 mL of 0.06 mol / L dodecyltrimethylammonium bromide aqueous solution, 5 mL of 0.01 mol / L silver nitrate aqueous solution, and 1 mL of 0.5 mol / L sodium borohydride aqueous solution were stirred evenly and reacted at room temperature for 8 hours to obtain a nanosilver-surfactant complex solution.

[0039] Preparation Example 3

[0040] The preparation method of the modified catalyst in this preparation example is:

[0041] Step A1: Add 10 g of activated carbon to 100 mL of 1 g / L nanosilver-surfactant complex solution, stir at 160 r / min for 3 h, then wash with water and dry to obtain modified activated carbon.

[0042] Step A2: 20 mL of anhydrous ethanol, 10 mL of tetrabutyl titanate, and 1.5 mL of glacial acetic acid are mixed to obtain a mixed solution A; 2.5 g of modified activated carbon is added to 30 mL of the mixed solution A, and then 13 mL of an ethanol aqueous solution with a volume fraction of 80% is added to obtain a gel; the gel is placed in a reactor for aging for 8 hours, and then hydrothermally reacted at 120° C. for 12 hours. After cooling to room temperature, it is taken out and washed with deionized water three times, filtered, and dried at 90° C. for 12 hours, and ground to obtain a modified catalyst.

[0043] The preparation method of the nanosilver-surfactant complex solution is the same as that in Preparation Example 1.

[0044] Preparation Example 4

[0045] The preparation method of the modified catalyst in this preparation example is:

[0046] Step A1: Add 10 g of activated carbon to 120 mL of 1 g / L nanosilver-surfactant complex solution, stir at 180 r / min for 3.5 h, then wash with water and dry to obtain modified activated carbon.

[0047] Step A2: 23 mL of anhydrous ethanol, 15 mL of tetrabutyl titanate, and 2 mL of glacial acetic acid are mixed to obtain a mixed solution A; 2.75 g of modified activated carbon is added to 32 mL of the mixed solution A, and then 16 mL of an ethanol aqueous solution with a volume fraction of 80% is added to obtain a gel; the gel is placed in a reactor for aging for 8 hours, and then hydrothermally reacted at 125° C. for 12 hours. After cooling to room temperature, it is taken out and washed with deionized water three times, filtered, and dried at 90° C. for 12 hours, and ground to obtain a modified catalyst.

[0048] The preparation method of the nanosilver-surfactant complex solution is the same as that in Preparation Example 1.

[0049] Preparation Example 5

[0050] The preparation method of the modified catalyst in this preparation example is:

[0051] Step A1: Add 10 g of activated carbon to 140 mL of 1 g / L nanosilver-surfactant complex solution, stir at 200 r / min for 4 h, then wash with water and dry to obtain modified activated carbon.

[0052] Step A2: 25 mL of anhydrous ethanol, 20 mL of tetrabutyl titanate, and 2.5 mL of glacial acetic acid are mixed to obtain a mixed solution A; 3 g of modified activated carbon is added to 35 mL of the mixed solution A, and then 18 mL of an ethanol aqueous solution with a volume fraction of 80% is added to obtain a gel; the gel is placed in a reactor for aging for 8 hours, and then hydrothermally reacted at 130° C. for 12 hours. After cooling to room temperature, it is taken out and washed with deionized water three times, filtered, and dried at 90° C. for 12 hours, and ground to obtain a modified catalyst.

[0053] The preparation method of the nanosilver-surfactant complex solution is the same as that in Preparation Example 1.

[0054] Preparation Example 6

[0055] The preparation method of the modified catalyst in this preparation example is different from that in Preparation Example 3, in that the "1 g / L nanosilver-surfactant complex solution" in Preparation Example 3 is replaced by "the product prepared in Preparation Example 2", and the remaining raw materials, processes and parameters are the same as those in Preparation Example 3.

[0056] Preparation Example 7

[0057] The preparation method of the modified catalyst in this preparation example is different from that in Preparation Example 3, the "1 g / L nanosilver-surfactant complex solution" in Preparation Example 3 is replaced by "1 g / L (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide aqueous solution", and the remaining raw materials, processes and parameters are the same as those in Preparation Example 3.

[0058] Preparation Example 8

[0059] The preparation method of the modified catalyst in this preparation example is:

[0060] 20 mL of anhydrous ethanol, 10 mL of tetrabutyl titanate, and 1.5 mL of glacial acetic acid were mixed to obtain a mixed solution A; 2.5 g of activated carbon was added to 30 mL of the mixed solution A, and then 13 mL of an ethanol aqueous solution with a volume fraction of 80% was added to obtain a gel; the gel was placed in a reactor for aging for 8 hours, and then hydrothermally reacted at 120° C. for 12 hours. After cooling to room temperature, it was taken out and washed with deionized water for 3 times, filtered, and dried at 90° C. for 12 hours, and ground to obtain a modified catalyst.

[0061] Example 1

[0062] This embodiment provides a method for treating thiophanate-methyl production wastewater, comprising the following steps:

[0063] Step S1: Add 30wt% sodium hydroxide aqueous solution to the wastewater to adjust the pH of the wastewater to 7-8. Add 2g of copper sulfate pentahydrate to 1L of methyl thiophanate production wastewater, and then pass it into a catalytic wet oxidation kettle for reaction to obtain a treated liquid I. The oxidant of the catalytic wet oxidation reaction is air or oxygen, and the flow rate of the air or oxygen is 40L / h; the temperature of the catalytic wet oxidation reaction is 210°C; the reaction pressure is 2MPa; and the reaction time is 2h.

[0064] Step S2: adding 1 g of the modified catalyst to 1 L of the treatment solution I, performing photocatalysis, the catalytic time is 0.5 h, the wavelength is 400 nm, and obtaining the treatment solution II;

[0065] Step S3: The treated liquid II is treated by distillation through a polytetrafluoroethylene hollow fiber membrane (the pore size of the membrane is 0.1 μm, the porosity is 70-90%, and the membrane thickness is 0.1 mm) to obtain the treated liquid III, thus completing the treatment.

[0066] The preparation steps of the modified catalyst are the same as those in Preparation Example 3.

[0067] According to the measurement, the COD removal rate of this embodiment is 96.3%, and the ammonia nitrogen removal rate is 87.5%.

[0068] Example 2

[0069] This embodiment provides a method for treating thiophanate-methyl production wastewater, comprising the following steps:

[0070] Step S1: Add 30wt% sodium hydroxide aqueous solution to the wastewater to adjust the pH of the wastewater to 7-8. Add 3g of copper sulfate pentahydrate to 1L of methyl thiophanate production wastewater, and then pass it into a catalytic wet oxidation kettle for reaction to obtain a treated liquid I. The oxidant of the catalytic wet oxidation reaction is air or oxygen, and the flow rate of the air or oxygen is 40L / h; the temperature of the catalytic wet oxidation reaction is 240°C; the reaction pressure is 4MPa; and the reaction time is 2.4h.

[0071] Step S2: adding 1.5 g of modified catalyst to 1 L of treatment solution I, performing photocatalysis, the catalytic time is 0.8 h, the wavelength is 400 nm, and obtaining treatment solution II;

[0072] Step S3: The treated liquid II is treated by distillation through a polytetrafluoroethylene hollow fiber membrane (the pore size of the membrane is 0.4 μm, the porosity is 70-90%, and the membrane thickness is 0.2 mm) to obtain the treated liquid III, thus completing the treatment.

[0073] The preparation steps of the modified catalyst are the same as those in Preparation Example 4.

[0074] According to the measurement, the COD removal rate of this embodiment is 97.6%, and the ammonia nitrogen removal rate is 89.2%.

[0075] Example 3

[0076] This embodiment provides a method for treating thiophanate-methyl production wastewater, comprising the following steps:

[0077] Step S1: Add 30wt% sodium hydroxide aqueous solution to the wastewater to adjust the pH of the wastewater to 7-8. Add 5g of copper sulfate pentahydrate to 1L of methyl thiophanate production wastewater, and then pass it into a catalytic wet oxidation kettle for reaction to obtain a treated liquid I. The oxidant of the catalytic wet oxidation reaction is air or oxygen, and the flow rate of the air or oxygen is 40L / h; the temperature of the catalytic wet oxidation reaction is 260°C; the reaction pressure is 6MPa; and the reaction time is 2.5h.

[0078] Step S2: adding 2 g of modified catalyst to 1 L of treatment solution I, performing photocatalysis, the catalytic time is 1 h, the wavelength is 400 nm, and obtaining treatment solution II;

[0079] Step S3: The treated liquid II is treated by distillation through a polytetrafluoroethylene hollow fiber membrane (the pore size of the membrane is 1 μm, the porosity is 70-90%, and the membrane thickness is 0.25 mm) to obtain the treated liquid III, thus completing the treatment.

[0080] The preparation steps of the modified catalyst are the same as those in Preparation Example 5.

[0081] According to the measurement, the COD removal rate of this embodiment is 98.6%, and the ammonia nitrogen removal rate is 92.1%.

[0082] Comparative Example 1

[0083] A method for treating wastewater produced by methyl thiophanate is disclosed. Compared with Example 1, the difference is that the modified catalyst in Example 1 is replaced by the product prepared in Preparation Example 6, and the remaining raw materials, processes and parameters are the same as Example 1.

[0084] According to the measurement, the COD removal rate of this embodiment is 85.5%, and the ammonia nitrogen removal rate is 81.1%.

[0085] Comparative Example 2

[0086] A method for treating wastewater produced by methyl thiophanate is disclosed. Compared with Example 1, the difference is that the modified catalyst in Example 1 is replaced by the product prepared in Preparation Example 7, and the remaining raw materials, processes and parameters are the same as Example 1.

[0087] According to the measurement, the COD removal rate of this embodiment is 80.5%, and the ammonia nitrogen removal rate is 79.3%.

[0088] Comparative Example 3

[0089] A method for treating wastewater produced by methyl thiophanate is disclosed. Compared with Example 1, the difference is that the modified catalyst in Example 1 is replaced by the product prepared in Preparation Example 8, and the remaining raw materials, processes and parameters are the same as Example 1.

[0090] According to the measurement, the COD removal rate of this embodiment is 74.8%, and the ammonia nitrogen removal rate is 72.4%.

[0091] By comparing Examples 1 to 3 with Comparative Examples 1 and 2, it can be seen that the effects of Examples 1 to 3 in treating wastewater are better than those of Comparative Examples 1 to 3. Comparative Example 1 replaces the surfactant containing a thiol group with a surfactant that does not contain a thiol group, which indicates that the thiol group has a strong interaction with silver, thereby stabilizing the nanosilver particles and preventing them from agglomerating, and helping to form a uniformly dispersed nanosilver-surfactant complex solution, which can improve the COD and ammonia nitrogen removal rates. The modified catalyst in Comparative Example 2 does not contain nanosilver, which indicates that nanosilver is beneficial to improving the catalytic efficiency, thereby reducing the COD value and ammonia nitrogen concentration of the wastewater. The modified catalyst in Comparative Example 3 does not contain nanosilver-surfactant, which indicates that the quaternary ammonium salt group can efficiently adsorb SCN under the action of electrostatics. - , thereby reducing the organic matter in the wastewater and reducing the COD value and ammonia nitrogen concentration in the methyl thiophanate production wastewater.

[0092] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0093] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for treating thiophanate-methyl production wastewater, characterized in that: The following steps are involved: Step S1: adding copper sulfate pentahydrate to the wastewater produced by thiophanate-methyl, and then passing it into a catalytic wet oxidation kettle for reaction to obtain a treated solution I; Step S2: adding a modified catalyst to the treatment liquid I to perform photocatalysis to obtain a treatment liquid II; Step S3: The treated liquid II is treated by three-stage membrane distillation to obtain the treated liquid III, thus completing the treatment.

2. A method for treating thiophanate-methyl production wastewater according to claim 1, characterized in that: Before step S1, 30 wt % sodium hydroxide aqueous solution is added to the wastewater to adjust the pH of the wastewater to 7-8.

3. A method for treating thiophanate-methyl production wastewater according to claim 1, characterized in that: In step S1, the oxidant for the catalytic wet oxidation reaction is air or oxygen, and the flow rate of air or oxygen is 40 L / h; the temperature of the catalytic wet oxidation reaction is 210-260°C; the reaction pressure is 2-6 MPa; and the reaction time is 2-2.5 h.

4. A method for treating thiophanate-methyl production wastewater according to claim 1, characterized in that: In step S1, the usage ratio of methyl thiophanate production wastewater to copper sulfate pentahydrate is 1L:2-5g.

5. A method for treating thiophanate-methyl production wastewater according to claim 1, characterized in that: In step S2, the dosage ratio of the treatment liquid I to the modified catalyst is 1L:1-2g; the photocatalytic time is 0.5-1h; and the wavelength of the photocatalytic is 400nm.

6. A method for treating thiophanate-methyl production wastewater according to claim 1, characterized in that: In step S2, the preparation steps of the modified catalyst are: Step A1: adding activated carbon to a 1 g / L nanosilver-surfactant complex solution, stirring at 160-200 r / min for 3-4 hours, washing with water, and drying to obtain modified activated carbon; Step A2: Anhydrous ethanol, tetrabutyl titanate and glacial acetic acid are mixed to obtain a mixed solution A; modified activated carbon is added to the mixed solution A, and then an ethanol aqueous solution with a volume fraction of 80% is added to obtain a gel; the gel is aged for 8 hours, reacted at 120-130° C. for 12 hours, cooled to room temperature, taken out, washed with water, filtered, dried, and ground to obtain a modified catalyst.

7. A method for treating thiophanate-methyl production wastewater according to claim 6, characterized in that: In step A1, the dosage ratio of 1g / L nanosilver-surfactant complex solution and activated carbon is 100-140mL:10g; in step A2, the volume ratio of anhydrous ethanol, tetrabutyl titanate and glacial acetic acid in the mixed solution A is 2-2.5:1-2:0.15-0.25; the dosage ratio of the mixed solution A, modified activated carbon and ethanol aqueous solution is 30-35mL:2.5-3g:13-18mL.

8. A method for treating thiophanate-methyl production wastewater according to claim 6, characterized in that: The preparation method of the nano silver-surfactant complex solution is as follows: A 0.06 mol / L aqueous solution of (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide, a 0.01 mol / L aqueous solution of silver nitrate, and a 0.5 mol / L aqueous solution of sodium borohydride were stirred evenly and reacted at room temperature for 8 hours to obtain a nanosilver-surfactant complex solution.

9. A method for treating thiophanate-methyl production wastewater according to claim 8, characterized in that: The volume ratio of the (11-mercaptoundecyl)-N,N,N-trimethylammonium bromide aqueous solution, the silver nitrate aqueous solution, and the sodium borohydride aqueous solution is 5:5:

1.

10. A method for treating thiophanate-methyl production wastewater according to claim 1, characterized in that: In step S3, the three-stage membrane distillation system uses a polytetrafluoroethylene hollow fiber membrane with a pore size of 0.1-1 μm, a porosity of 70-90%, and a membrane thickness of 0.1-0.25 mm.