A kind of phenylenediamine production wastewater treatment system and method

Abstract

The present invention discloses a phenylenediamine production wastewater treatment system and method, comprising the following steps: S1 micro-electrolysis reaction; S2 Fenton reaction; S3 ultrafiltration system; S4 triple-effect evaporation system; S5 biochemical treatment system. The present invention can effectively improve the removal rate of difficult-to-biodegrade organic matter by using microbial enhancement technology and bacterial agents suitable for wastewater treatment containing difficult-to-biodegrade organic matter, as the phenylenediamine wastewater contains a relatively high concentration of difficult-to-biodegrade organic matter.

Description

Technical Field

[0001] The invention relates to the technical field of phenylenediamine production, and in particular to a phenylenediamine production wastewater treatment system and method. Background Art

[0002] As an important organic chemical raw material, phenylenediamine is widely used in many fields such as dyes, rubber additives, pesticides, and medicines. With the continuous expansion of the production scale of phenylenediamine, the large amount of wastewater generated in its production process has become a serious environmental problem.

[0003] Wastewater from the production of phenylenediamine has the remarkable characteristics of complex composition, high concentration of pollutants, high toxicity and poor biodegradability. It contains a variety of organic pollutants such as unreacted phenylenediamine raw materials, reaction intermediates and by-products. These substances often have a benzene ring structure and high chemical stability, making it difficult to effectively degrade them through conventional biological treatment methods. For example, residual phenylenediamine substances in wastewater have a significant inhibitory effect on microorganisms, which will lead to reduced activity or even death of microorganisms in the biological treatment system, thus making it impossible for the biological treatment process to operate normally.

[0004] Traditional physical and chemical treatment methods, such as coagulation, sedimentation, and adsorption, can remove some pollutants in wastewater to a certain extent, but they are limited in their effect on the removal of refractory organic matter in phenylenediamine production wastewater, and there are problems such as high treatment costs and a large amount of secondary pollution. For example, when using activated carbon adsorption treatment, the regeneration of activated carbon is difficult and costly, and if the activated carbon is not properly handled after adsorption saturation, it will become a new source of pollution.

[0005] Chemical oxidation methods, such as ozone oxidation and Fenton oxidation, have strong oxidation ability and can destroy the benzene ring structure of phenylenediamine and its derivatives and improve the biodegradability of wastewater. However, when used alone, they often have defects such as low oxidation efficiency, large consumption of reagents, and difficulty in stabilizing the effluent after treatment. For example, a large amount of hydrogen peroxide and ferrous salts are consumed in the Fenton oxidation process, and the iron sludge produced by the reaction also needs to be properly handled later, which increases the treatment cost and operation difficulty.

[0006] In addition, although some existing combined treatment processes have integrated the advantages of multiple treatment methods to a certain extent, they still have problems such as complex process flows, large equipment investments, and high operation and management requirements, making them difficult to promote and apply on a large scale in actual industrial production.

[0007] In summary, the current treatment technology for phenylenediamine production wastewater is difficult to meet the increasingly stringent environmental protection requirements and the actual needs of enterprises. It is urgent to develop a new method for treating phenylenediamine production wastewater that is efficient, economical, environmentally friendly and easy to industrialize, so as to achieve the sustainable development of the phenylenediamine production industry and reduce harm to the environment. Summary of the invention

[0008] In order to solve the problems mentioned in the above background technology, the present invention provides a phenylenediamine production wastewater treatment system and method.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A method for treating wastewater from the production of phenylenediamine comprises the following steps:

[0011] S1 micro-electrolysis reaction:

[0012] The phenylenediamine wastewater enters a comprehensive wastewater regulating tank equipped with a stirring device, which is used to store and mix the phenylenediamine wastewater; then it enters a micro-electrolysis reactor for micro-electrolysis reduction reaction, and the conditions are controlled to be neutral;

[0013] Micro-electrolysis reactor: The basic principle is to use iron and other conductors to form countless tiny primary cells. Under pH neutral conditions, the nitro groups on the benzene rings of organic pollutants in wastewater can be reduced to amine groups and other groups, thereby significantly reducing the safety hazards of subsequent evaporation and concentration processes. The use of special iron-copper internal electrolysis materials and multi-stage internal electrolysis equipment can perform electrolytic reduction reactions under neutral conditions, and can greatly improve the reduction efficiency of nitro compounds in wastewater.

[0014] S2 Fenton reaction:

[0015] The wastewater after micro-electrolysis treatment enters the Fenton reaction sedimentation tank. The wastewater contains a large amount of Fe 2+ The addition of hydrogen peroxide will cause a Fenton reaction, producing ·OH with strong oxidizing properties, which can significantly reduce the amount of organic pollutants in the wastewater through oxidation reactions and destroy the ring structure of benzene series.

[0016] S3 Ultrafiltration System:

[0017] The wastewater after the Fenton reaction enters the ultrafiltration membrane pool. The ultrafiltration system in the ultrafiltration membrane pool is used to remove fine suspended matter in the wastewater, creating good conditions for subsequent triple-effect evaporation.

[0018] The ultrafiltration system includes an ultrafiltration membrane, and the preparation method of the ultrafiltration membrane includes the following steps:

[0019] Step S3-1, adding N-methylpyrrolidone to ethylene-tetrafluoroethylene copolymer and carboxymethyl cellulose, stirring at a constant temperature of 45-55° C.; then standing and degassing at room temperature to obtain an ultrafiltration base membrane casting solution;

[0020] Preferably, the mass ratio of N-methylpyrrolidone, ethylene-tetrafluoroethylene copolymer and carboxymethyl cellulose is (5-8): (10-13): 2.3.

[0021] Step S3-2, the ultrafiltration base membrane casting liquid obtained in step S3-1 is evenly coated on the non-woven fabric substrate, and then enters the pure water gel bath, the gel bath temperature is 35-45°C, and the solvent exchange in the membrane is ensured to be complete in the coagulation bath. The ambient temperature during the coating process is 30-40°C, and the ambient humidity is 45-50%; the drying process is 10-12cm; the film scraping rate is 2-3.5m / min to obtain a base membrane containing a non-woven fabric substrate;

[0022] Step S3-3, treating the base film containing the non-woven fabric substrate prepared in step S3-2 with alkali to introduce double bonds;

[0023] Preferably, the alkali treatment is to immerse the base film containing the non-woven fabric substrate obtained in step S2 in an alcohol solution of an alkali metal hydroxide having a mass concentration of 1 to 3%.

[0024] Preferably, the alcoholic solution of alkali metal hydroxide is an ethanolic potassium hydroxide solution and / or an ethanolic sodium hydroxide solution.

[0025] Step S3-4, immersing the membrane treated with alkali in step S3-3 in a composite micro-nanotube dispersion, and adding ethylenediaminetetraacetic acid to obtain an ultrafiltration membrane.

[0026] The alkali-treated membrane is immersed in a composite micro-nanotube dispersion and ethylenediaminetetraacetic acid is added to chemically modify the membrane surface of the base membrane so that the composite micro-nanotube dispersion is better adsorbed on the membrane surface.

[0027] Since the composite micro-nanotubes may be difficult to disperse evenly in the solution due to their own agglomeration and other reasons, ethylenediaminetetraacetic acid (EDTA) can chelate with metal ions that may exist on the surface of the composite micro-nanotubes to change the surface charge or chemical environment of the composite micro-nanotubes, thereby reducing their agglomeration phenomenon, allowing the composite micro-nanotubes to be more evenly dispersed in the solution and then more evenly adsorbed on the surface of the membrane.

[0028] At the same time, EDTA acts as a "bridge" to enhance the interaction between the composite micro-nanotubes and the membrane. For example, it may chemically react or physically adsorb with certain functional groups (such as hydroxyl, carboxyl, etc.) on the membrane surface and active sites on the surface of the composite micro-nanotubes to form a stronger connection. This allows the composite micro-nanotubes to be more stably attached to the membrane and not easily fall off in subsequent processes such as ultrafiltration, thereby better exerting the performance of the composite micro-nanotubes, such as improving the mechanical strength of the membrane and improving the filtration performance of the membrane.

[0029] Furthermore, the preparation method of the composite micro-nanotube dispersion is as follows:

[0030] Polydibenzothiophene and polydopamine are dissolved in NMP, and then carbon nanotubes are added and dispersed by ultrasonic oscillation to obtain a composite micro-nanotube dispersion.

[0031] Preferably, the carbon nanotubes have a particle size of 5-8 μm and a specific surface area of ​​1600-2000 m 2 / g, pore volume is 0.8-1.0cm 3 / g.

[0032] Preferably, the mass ratio of the polydibenzothiophene, polydopamine, NMP and carbon nanotubes is (1-3): (1-5): 11: (1.3-2.1).

[0033] The combination of polydibenzothiophene and polydopamine will enhance the stability of the entire system. Polydopamine can protect polydibenzothiophene from external environmental factors (such as oxidation, hydrolysis, etc.) to a certain extent, prolong its effective use time in the dispersion, and after combining with the membrane, it can enable the composite micro-nanotubes to better resist the erosion of the membrane by chemicals.

[0034] S4 triple effect evaporation system:

[0035] The wastewater after the ultrafiltration membrane pool is initially precipitated in the intermediate water pool, and then enters the three-effect evaporation system for evaporation and concentration of high-salt wastewater. The generated condensed water enters the subsequent wastewater treatment system, and the concentrated liquid enters the crystallizer for crystallization treatment. The generated waste salt is safely disposed of.

[0036] S5 Biochemical Treatment System:

[0037] The high-salt wastewater is evaporated and concentrated by the three-effect evaporation system and then enters the intermediate water tank 2 for re-precipitation, and then enters the comprehensive biochemical pool. The biochemical treatment system in the comprehensive biochemical pool removes organic pollutants in the wastewater through the life activities of various microorganisms under different dissolved oxygen conditions.

[0038] A phenylenediamine production wastewater treatment system comprises a comprehensive wastewater regulating tank, a micro-electrolysis reactor, a Fenton reaction sedimentation tank, an ultrafiltration membrane tank, an intermediate water tank 1, a triple-effect evaporation system, an intermediate water tank 2 and a comprehensive biochemical tank which are connected in sequence.

[0039] In view of the fact that diphenylenediamine wastewater contains relatively high concentrations of biodegradable organic matter, microbial enhancement technology and bacterial agents suitable for wastewater treatment containing biodegradable organic matter are used to improve the removal rate of biodegradable organic matter.

[0040] The sludge in the biochemical treatment system is refluxed to the front end of the corresponding system through the sludge pump, and the residual sludge generated by the system is transported to the sludge thickening tank through the sludge pump bypass pipeline. In addition, the physical and chemical sludge generated by the integrated Fenton treatment device is transported to the sludge thickening tank through the sludge pump for further concentration and discharge of the supernatant. The supernatant flows to the ditch to the regulating tank, and the bottom sludge enters the dewatering machine for dehydration. It is turned on when the sludge volume in the sludge thickening tank exceeds 1 / 2 of the volume, and a single operation ends when the sludge volume in the sludge thickening tank is dehydrated to less than 1 / 5 of the volume.

[0041] (1) Preparation of flocculant: Fill the PAM dissolving device with clean water, turn on the dissolving device agitator, slowly add 1 kg of PAM, and continue stirring for more than 2 hours for use.

[0042] (2) Sludge thickening: The liquid level in the sludge thickening tank should be more than 1 / 2. Open the bypass pipeline valve of the sludge pump in the secondary sedimentation tank, and the biochemical system starts to discharge sludge; open the sludge discharge pump of the integrated Fenton treatment device, and the integrated Fenton treatment device starts to discharge sludge into the sludge thickening tank. After the sludge starts to enter the sludge thickening tank, start the thickener.

[0043] (3) Sludge filter press:

[0044] ①Open the inlet and outlet valves of the dehydrator mud pump and start the mud pump;

[0045] ② Adjust the sludge pump outlet valve and reflux valve to adjust the sludge flow rate of the screw filter press;

[0046] ③ Start the PAM dosing pump, observe the flow meter value of the dosing pipe, and adjust the stroke by rotating the dosing pump stroke knob to adjust the flow;

[0047] ④Start the Deluo dehydrator;

[0048] ⑤ Adjust the dosage / mud input and stacking operation frequency according to the mud discharge status.

[0049] Biochemical treatment part:

[0050] (1) Treatment objects: triple-effect evaporation condensate, part of dinitrosulfuric acid concentrated wastewater, diamine wastewater and flushing wastewater

[0051] (2) Processing capacity: 200m³ / d, 8m³ / h.

[0052] (3) Water inlet index:

[0053] (4) COD: ≤5000mg / l, TDS: ≤4000mg / l, TN ≤300mg / l; pH: neutral;

[0054] (5) Water output index:

[0055] COD: ≤500mg / l, TDS: ≤4000mg / l, TN ≤70mg / l, pH: neutral.

[0056] The technical indicators of microbial carrier agents are shown in Table 1:

[0057] Table 1 Technical indicators of microbial carrier agents

[0058]

[0059] Compared with the prior art, the present invention has the following beneficial effects:

[0060] 1. The present invention can effectively improve the removal rate of difficult-to-biodegrade organic matter by using microbial enhancement technology and bacterial agents suitable for treating wastewater containing difficult-to-biodegrade organic matter in the p-phenylenediamine wastewater containing relatively high concentrations of difficult-to-biodegrade organic matter.

[0061] 2. The present invention can effectively intercept macromolecular impurities such as proteins, colloids, bacteria, viruses, etc. in wastewater through a self-made ultrafiltration membrane. During the preparation process of the ultrafiltration membrane, the membrane after alkali treatment is immersed in a composite micro-nanotube dispersion, and ethylenediaminetetraacetic acid is added to chemically modify the membrane surface of the base membrane, so that the composite micro-nanotube dispersion is better adsorbed on the membrane surface. The composite micro-nanotube dispersion overcomes the problems of uneven dispersion of traditional carbon nanomaterials and poor strength after grafting functional groups, thereby improving the flux, BSA retention rate and mechanical strength of the ultrafiltration membrane. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0063] Figure 1 Schematic diagram of the process of the system of the present invention. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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.

[0065] Preparation Example 1

[0066] The preparation method of the composite micro-nanotube dispersion is as follows:

[0067] 10g of polydibenzothiophene and 15g of polydopamine were dissolved in 110g of NMP, and 13g of polydibenzothiophene with a particle size of 5 μm and a specific surface area of ​​2000 m 2 / g, pore volume 1.0cm 3 / g carbon nanotubes are added and dispersed by ultrasonic oscillation to obtain a composite micro-nanotube dispersion.

[0068] Preparation Example 2

[0069] The preparation method of the composite micro-nanotube dispersion is as follows:

[0070] 20g of polydibenzothiophene and 30g of polydopamine were dissolved in 110g of NMP, and 18g of 6μm particle size and 1800m 2 / g, pore volume 0.9cm 3 / g carbon nanotubes are added and dispersed by ultrasonic oscillation to obtain a composite micro-nanotube dispersion.

[0071] Preparation Example 3

[0072] The preparation method of the composite micro-nanotube dispersion is as follows:

[0073] 30g of polydibenzothiophene and 35g of polydopamine were dissolved in 110g of NMP, and 21g of polydibenzothiophene with a particle size of 7μm and a specific surface area of ​​1650m 2 / g, pore volume 0.8cm 3 / g carbon nanotubes are added and dispersed by ultrasonic oscillation to obtain a composite micro-nanotube dispersion.

[0074] Preparation Example 4

[0075] The preparation method of the ultrafiltration membrane comprises the following steps:

[0076] Step S3-1, adding 50 g of N-methylpyrrolidone to 110 g of ethylene-tetrafluoroethylene copolymer and 23 g of carboxymethyl cellulose, stirring at a constant temperature of 45° C., and then standing at room temperature for degassing to obtain an ultrafiltration base membrane casting solution;

[0077] Step S3-2, the ultrafiltration base membrane casting liquid obtained in step S3-1 is uniformly coated on the non-woven fabric substrate, and then enters the pure water gel bath, the gel bath temperature is 35°C, and the solvent exchange in the membrane is ensured to be complete in the coagulation bath. The ambient temperature during the coating process is 35°C and the ambient humidity is 45%; the drying distance is 10 cm; the scraping rate is 2.5 m / min to obtain a base membrane containing a non-woven fabric substrate;

[0078] Step S3-3, soaking the base film containing the non-woven fabric substrate prepared in step S3-2 in a potassium hydroxide ethanol solution with a mass concentration of 2%;

[0079] Step S3-4, immersing the membrane after the alkali treatment in step S3 in 500 mL of the composite micro-nanotube dispersion prepared in Preparation Example 1, and adding ethylenediaminetetraacetic acid to obtain an ultrafiltration membrane.

[0080] Preparation Example 5

[0081] The preparation method of the ultrafiltration membrane comprises the following steps:

[0082] Step S3-1, adding 70 g of N-methylpyrrolidone to 100 g of ethylene-tetrafluoroethylene copolymer and 23 g of carboxymethyl cellulose, stirring at a constant temperature of 45° C.; then standing at room temperature for degassing to obtain an ultrafiltration base membrane casting solution;

[0083] Step S3-2, the ultrafiltration base membrane casting liquid obtained in step S3-1 is uniformly coated on the non-woven fabric substrate, and then enters the pure water gel bath, the gel bath temperature is 35°C, and the solvent exchange in the membrane is ensured to be complete in the coagulation bath. The ambient temperature during the coating process is 35°C and the ambient humidity is 45%; the drying distance is 10 cm; the scraping rate is 2.5 m / min to obtain a base membrane containing a non-woven fabric substrate;

[0084] Step S3-3, soaking the base film containing the non-woven fabric substrate prepared in step S3-2 in a potassium hydroxide ethanol solution with a mass concentration of 3%;

[0085] Step S3-4, immersing the membrane after the alkali treatment in step S3 in 500 mL of the composite micro-nanotube dispersion prepared in Preparation Example 2, and adding ethylenediaminetetraacetic acid to obtain an ultrafiltration membrane.

[0086] Preparation Example 6

[0087] The preparation method of the ultrafiltration membrane comprises the following steps:

[0088] Step S3-1, adding 80 g of N-methylpyrrolidone to 130 g of ethylene-tetrafluoroethylene copolymer and 23 g of carboxymethyl cellulose, stirring at a constant temperature of 45° C.; then standing and degassing at room temperature to obtain an ultrafiltration base membrane casting solution;

[0089] Step S3-2, the ultrafiltration base membrane casting liquid obtained in step S3-1 is uniformly coated on the non-woven fabric substrate, and then enters the pure water gel bath, the gel bath temperature is 35°C, and the solvent exchange in the membrane is ensured to be complete in the coagulation bath. The ambient temperature during the coating process is 35°C and the ambient humidity is 45%; the drying distance is 10 cm; the scraping rate is 2.5 m / min to obtain a base membrane containing a non-woven fabric substrate;

[0090] Step S3-3, soaking the base film containing the non-woven fabric substrate prepared in step S3-2 in a potassium hydroxide ethanol solution with a mass concentration of 2%;

[0091] Step S3-4, immersing the membrane after the alkali treatment in step S3 in 500 mL of the composite micro-nanotube dispersion prepared in Preparation Example 3, and adding ethylenediaminetetraacetic acid to obtain an ultrafiltration membrane.

[0092] Example 1

[0093] A method for treating wastewater from the production of phenylenediamine comprises the following steps:

[0094] S1 micro-electrolysis reaction:

[0095] The phenylenediamine wastewater enters a comprehensive wastewater regulating tank equipped with a stirring device, which is used to store and mix the phenylenediamine wastewater; then it enters a micro-electrolysis reactor for micro-electrolysis reduction reaction, and the conditions are controlled to be neutral;

[0096] S2 Fenton reaction:

[0097] The wastewater after micro-electrolysis treatment enters the Fenton reaction sedimentation tank. The wastewater contains a large amount of Fe 2+ , adding hydrogen peroxide will cause Fenton reaction;

[0098] S3 Ultrafiltration System:

[0099] The wastewater after the Fenton reaction enters the ultrafiltration membrane pool, and the ultrafiltration system in the ultrafiltration membrane pool is used to remove fine suspended matter in the wastewater, and the ultrafiltration system includes the ultrafiltration membrane prepared in Preparation Example 4;

[0100] S4 triple effect evaporation system:

[0101] The wastewater after the ultrafiltration membrane pool is put into the intermediate water pool for preliminary precipitation, and then enters the three-effect evaporation system for evaporation and concentration of high-salt wastewater. The generated condensed water enters the subsequent wastewater treatment system, and the concentrated liquid enters the crystallizer for crystallization treatment. The generated waste salt is safely disposed of;

[0102] S5 Biochemical Treatment System:

[0103] The high-salt wastewater is evaporated and concentrated by the three-effect evaporation system and then enters the intermediate water tank 2 for re-precipitation, and then enters the comprehensive biochemical pool. The biochemical treatment system in the comprehensive biochemical pool removes organic pollutants in the wastewater through the life activities of various microorganisms under different dissolved oxygen conditions.

[0104] Example 2

[0105] The difference between this embodiment and Example 1 is that the ultrafiltration system includes the ultrafiltration membrane prepared in Preparation Example 5.

[0106] Example 3

[0107] The difference between this embodiment and embodiment 1 is that the ultrafiltration system includes the ultrafiltration membrane prepared in Preparation Example 6.

[0108] Comparative Example 1

[0109] The difference between this comparative example and Example 1 is that the ultrafiltration membrane prepared in Preparation Example 4 is replaced by a common commercially available ultrafiltration membrane purchased from Tianjin Hanqing Environmental Protection Technology Co., Ltd., model CC-UF8060.

[0110] Comparative Example 2

[0111] The difference between this embodiment and embodiment 1 is that in the preparation process of preparation example 4, no composite micro-nanotube dispersion liquid is added.

[0112] The ultrafiltration membranes prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to membrane performance testing and characterization in accordance with GB / T32360-2015 and GB / T30693-2014. The results are shown in Table 2:

[0113] Table 2 Performance test results of Examples 1-3 and Comparative Examples 1-2

[0114]

[0115] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for treating wastewater from the production of phenylenediamine, characterized in that: The following steps are involved: S1 micro-electrolysis reaction: The phenylenediamine wastewater enters a comprehensive wastewater regulating tank equipped with a stirring device, which is used to store and mix the phenylenediamine wastewater; then it enters a micro-electrolysis reactor for micro-electrolysis reduction reaction, and the conditions are controlled to be neutral; S2 Fenton reaction: The wastewater after micro-electrolysis treatment enters the Fenton reaction sedimentation tank. The wastewater contains a large amount of Fe 2+ , adding hydrogen peroxide will cause Fenton reaction; S3 Ultrafiltration System: The wastewater after Fenton reaction enters the ultrafiltration membrane pool, and the ultrafiltration system in the ultrafiltration membrane pool is used to remove fine suspended matter in the wastewater; S4 triple effect evaporation system: The wastewater after the ultrafiltration membrane pool is put into the intermediate water pool for preliminary precipitation, and then enters the three-effect evaporation system for evaporation and concentration of high-salt wastewater. The generated condensed water enters the subsequent wastewater treatment system, and the concentrated liquid enters the crystallizer for crystallization treatment. The generated waste salt is safely disposed of; S5 Biochemical Treatment System: After being evaporated and concentrated by the three-effect evaporation system, the high-salinity wastewater enters the intermediate water tank 2 for re-precipitation, and then enters the comprehensive biochemical pool. The biochemical treatment system in the comprehensive biochemical pool removes organic pollutants in the wastewater through the life activities of various microorganisms under different dissolved oxygen conditions; The ultrafiltration system comprises an ultrafiltration membrane, and the preparation method of the ultrafiltration membrane comprises the following steps: Step S3-1, adding N-methylpyrrolidone to ethylene-tetrafluoroethylene copolymer and carboxymethyl cellulose, stirring at a constant temperature of 45-55° C.; then standing and degassing at room temperature to obtain an ultrafiltration base membrane casting solution; Step S3-2, uniformly coating the ultrafiltration base membrane casting liquid obtained in step S3-1 on the non-woven fabric substrate, and then entering the pure water gel bath; the dry distance is 10-12 cm; the scraping rate is 2-3.5 m / min to obtain the base membrane containing the non-woven fabric substrate; Step S3-3, treating the base film containing the non-woven fabric substrate prepared in step S3-2 with alkali to introduce double bonds; Step S3-4, immersing the membrane after the alkali treatment in step S3 in a composite micro-nanotube dispersion, and adding ethylenediaminetetraacetic acid to obtain an ultrafiltration membrane; The preparation method of the composite micro-nanotube dispersion is as follows: Polydibenzothiophene and polydopamine are dissolved in NMP, and then carbon nanotubes are added and dispersed by ultrasonic oscillation to obtain a composite micro-nanotube dispersion.

2. A method for treating phenylenediamine production wastewater according to claim 1, characterized in that: The mass ratio of the N-methylpyrrolidone, ethylene-tetrafluoroethylene copolymer and carboxymethyl cellulose is (5-8): (10-13): 2.

3.

3. A method for treating phenylenediamine production wastewater according to claim 1, characterized in that: The control conditions of the pure water gel bath are as follows: the gel bath temperature is 35-45° C., the solvent exchange in the film is ensured to be complete in the coagulation bath, the ambient temperature during the coating process is 30-40° C., and the ambient humidity is 45-50%.

4. A method for treating phenylenediamine production wastewater according to claim 1, characterized in that: The alkali treatment is to immerse the base film containing the non-woven fabric substrate in an alcohol solution of an alkali metal hydroxide with a mass concentration of 1 to 3%.

5. A method for treating phenylenediamine production wastewater according to claim 4, characterized in that: The alcohol solution of alkali metal hydroxide is potassium hydroxide ethanol solution and / or sodium hydroxide ethanol solution.

6. A method for treating phenylenediamine production wastewater according to claim 1, characterized in that: The carbon nanotubes have a particle size of 5-8 μm and a specific surface area of ​​1600-2000 m 2 / g, pore volume is 0.8-1.0cm 3 / g.

7. A method for treating phenylenediamine production wastewater according to claim 1, characterized in that: The mass ratio of the polydibenzothiophene, polydopamine, NMP and carbon nanotubes is (1-3): (1-5): 11: (1.3-2.1).

8. A phenylenediamine production wastewater treatment system, using the phenylenediamine production wastewater treatment method according to any one of claims 1 to 7, characterized in that: It includes a comprehensive wastewater regulating tank, a micro-electrolysis reactor, a Fenton reaction sedimentation tank, an ultrafiltration membrane tank, an intermediate water tank 1, a three-effect evaporation system, an intermediate water tank 2 and a comprehensive biochemical tank which are connected in sequence.

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