A method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp

Abstract

The present invention discloses a method for treating organic wastewater by using a graphene aerogel microchannel reactor and an ultraviolet lamp, comprising a microchannel reactor module including a microchannel reaction tube and an ultraviolet lamp; each microchannel reactor module is provided with a plurality of microchannel reaction tubes, and the microchannel reaction tubes are cylindrical tubular structures. The method for treating organic wastewater by using a microchannel reactor of the present invention has the characteristics of small footprint, large treatment capacity, quick effect, low energy consumption, easy maintenance, etc. The present invention utilizes the photocatalytic technology in the chemical conversion method to rapidly oxidize and completely degrade organic pollutants in water. The charge generated by light energy drive can be transferred to the surface of the photocatalytic material and mineralize the macromolecular organic matter near the active center into harmless substances.

Description

Technical Field

[0001] The invention relates to the field of organic wastewater treatment, and in particular to a method for treating organic wastewater by using a graphene aerogel microchannel reactor and an ultraviolet lamp. Background Art

[0002] With the rapid development of modern industrialization, organic wastewater composed of industrial dyes and cleaning wastewater generated by the chemical, pharmaceutical and other industries has greatly aggravated the pollution of global water resources and soil. The negative impact on the ecosystem and the potential harm to public health make it urgent to solve this problem. At present, the methods for purifying organic wastewater generated by industry are mainly divided into adsorption removal, chemical conversion and biodegradation.

[0003] The method of treating organic wastewater by adsorption removal, for example, in the prior art, the application number is: CN201510954497.5 discloses a method for treating high-concentration organic wastewater, which specifically includes the following steps: 1. Preparation of modified zeolite: After roasting magnesium oxide solid for a certain period of time, cooling, and microwave loading with zeolite in a certain ratio, after cooling, the modified zeolite loaded with magnesium oxide is obtained. 2. Treatment of organic wastewater: Adding modified zeolite in a certain ratio to organic wastewater, after a certain reaction time, a good adsorption and removal effect of ammonia nitrogen, phosphorus, etc. in the organic wastewater can be achieved.

[0004] Another example is the method of using biodegradation to treat organic wastewater. For example, application number: CN201310190619.9 discloses a method for biodegrading organic wastewater using microorganisms, which is characterized in that the method includes the following processes: 1) using dry reeds as fillers and biological carriers, 2) using a biological fluidized bed or fixed bed to treat the organic wastewater; the dry reeds are reeds picked after maturity, the reeds are hollow columns, cut into a length of 1cm-3cm according to specifications; soaked in clean water; the biological fluidized bed or fixed bed is used to treat the organic wastewater , including 1) placing soaked reeds in a fluidized bed or fixed bed reactor as biological fillers; 2) introducing organic wastewater with a pH of 6-9, aerating it, with a gas-water weight ratio of 4-20:1, and forming biofilms in a continuous water inlet manner, with the bioload on the filler reaching 9-45g / L, which is considered successful; 3) the organic wastewater added has a fill rate of 20-50% for the fluidized bed filler and a fill rate of 100% for the fixed bed filler, and aeration biochemical treatment is performed, with a COD volume load of 0.6-2.7kgCOD / (m3·d), and a hydraulic retention time of 1-6h;

[0005] However, neither physical nor biological methods can completely remove toxic pollutants in organic wastewater, and require high investment and operating costs. In view of the above, it is necessary to propose a method for treating organic wastewater using a graphene aerogel microchannel reactor and ultraviolet lamp to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to solve the above technical problems and to provide a method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme: a method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp, comprising the following steps:

[0008] Step 1: connecting the wastewater regulating tank to the hydrolysis acidification tank via a lifting pump, and providing a first submersible mixer in the hydrolysis acidification tank;

[0009] Step 2: Allow the water flowing out of the hydrolysis acidification tank to flow into the primary aerobic tank by itself, and an aeration system is provided in the primary aerobic tank;

[0010] Step 3: Allow the water flowing out of the primary aerobic pool to flow into the anoxic pool by itself, and a second submersible mixer is provided in the anoxic pool;

[0011] Step 4: The water flowing out of the anoxic tank flows into the secondary aerobic tank by itself, and an aeration system is arranged in the secondary aerobic tank; the water flowing out of the secondary aerobic tank flows into the MBR (membrane-bioreactor) membrane tank by itself, and an MBR membrane assembly is arranged in the MBR membrane tank, and the water is pumped into the microchannel reactor treatment tank through the outlet of the MBR membrane assembly by a membrane suction pump;

[0012] Step 5: A sludge return pump is installed at the bottom of the MBR membrane tank, and the sludge is returned to the primary aerobic tank through the pipeline. Some of the remaining sludge is discharged through the sludge discharge pipeline. A nitrification liquid return pump is installed at the bottom of the anoxic tank, and the nitrification liquid is returned to the hydrolysis acidification tank through the pipeline.

[0013] The MBR membrane assembly in the membrane pool pumps water to the microchannel reactor treatment pool through a membrane suction pump; the microchannel reactor treatment pool is provided with a number of microchannel reactor modules, and the sewage flows through the microchannel reactor modules to photocatalytically degrade the organic sewage;; the microchannel reactor treatment pool is provided with a number of microchannel reactor modules, and the sewage flows through the microchannel reactor modules to photocatalytically degrade the organic sewage;

[0014] The microchannel reactor module comprises a microchannel reaction tube and an ultraviolet lamp; each of the microchannel reactor modules is arranged in a matrix and has a plurality of microchannel reaction tubes arranged in parallel, the microchannel reaction tube is a cylindrical tubular structure, and its lower end is a closed mouth, the microchannel reactor tube of the cylindrical tubular structure comprises an outer tube and an inner tube arranged coaxially, at least the inner tube is made of a transparent material, an annular closed ring cavity is formed between the outer tube and the inner tube, a light introduction cavity is formed inside the inner tube, an aerogel porous material modified with graphene is arranged in the closed ring cavity, and the aerogel porous material is modified with PDA (polydopamine) / TiO2 / AgCl / Ag to form a photocatalytic material; the closed ring cavity is filled with photocatalytic material, the outer wall of the lower end of the outer tube is provided with a water inlet hole connected to the closed ring cavity, and the upper end of the microchannel reaction tube is provided with a water outlet hole; the water outlet holes of several microchannel reaction tubes converge into an intermediate water pool.

[0015] Furthermore, the graphene-modified aerogel porous material is prepared by an acid-base two-step sol-gel method;

[0016] In the first step, EtOH (ethanol), TEOS (ethyl silicate) and an appropriate amount of hydrochloric acid in a volume ratio of 30:1 were mixed to form a precursor solution (so that the pH value of the mixed solution was 3-4), and then stirred at room temperature for 90 minutes; in the second step, graphene oxide powder was dissolved in ethanol; then the dispersed GO sheets were ultrasonically peeled for 1 hour to obtain a GO aqueous dispersion; different masses of GO solution were added to the precursor solution to obtain GO-doped sol;

[0017] After magnetic stirring for 12 h, 1 mol / L ammonia water was added to the pure SiO2 sol and GO / SiO2 sol until the pH value reached 6-7 while being fully hydrolyzed and evenly dispersed. The sol was poured into a mold and aged at room temperature. The wet gel was placed in an ethanol bath at room temperature to remove any residual impurities or moisture. GO / SiO2 aerogel was obtained by supercritical CO2 drying.

[0018] Furthermore, the photocatalytic material is prepared in the following manner:

[0019] Modification of aerogel porous materials by polydopamine (PDA)

[0020] The aerogel porous material was ultrasonically washed in anhydrous ethanol; the washed aerogel porous material was immersed in an aqueous solution of dopamine hydrochloride, and then an aqueous solution of tris(hydroxymethyl)aminomethane was added to the reaction system to make the pH of the aqueous solution equal to 8.5, and stirred for 24 hours; finally, the obtained modified material was rinsed with other substances on the surface under deionized water, and dried at 60°C, which was recorded as aerogel / PDA;

[0021] Preparation of TiO2 modified aerogel porous materials

[0022] Ammonium fluorotitanate and boric acid were dissolved in deionized water with a mass ratio of ammonium fluorotitanate: boric acid: deionized water = 1:1:100; then, the aerogel / PDA was immersed in the mixed solution and continuously oscillated for 4 hours at 40°C; finally, the prepared TiO2-modified aerogel porous material was washed with deionized water for several times and dried at 80°C for subsequent experiments, which was recorded as aerogel / PDA / TiO2;

[0023] Preparation of TiO2 / AgCl / Ag modified aerogel porous materials

[0024] In order to prepare the PDA / TiO2 / AgCl / Ag modified aerogel porous material, the prepared aerogel / PDA / TiO2 aerogel porous material was soaked in a 0.9wt% silver nitrate aqueous solution for 30min, and then zinc chloride was added to the solution, the mass ratio of zinc chloride to silver nitrate was 0.3-0.4:1, and gently stirred for 30min. Then, the sample was reduced with a xenon lamp for 30min to form Ag / AgCl in situ on the surface of aerogel / PDA / TiO2: the prepared PDA / TiO2 / AgCl / Ag modified aerogel porous material was rinsed with deionized water and dried overnight in a vacuum, which was recorded as aerogel / PDA / TiO2 / AgCl / Ag.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: the method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp has the characteristics of small footprint, large treatment capacity, quick effect, low energy consumption, easy maintenance, etc. The present invention can quickly oxidize and completely degrade organic pollutants in water by using the photocatalytic technology in the chemical conversion method. After the photocatalyst absorbs ultraviolet light, the charge generated by light energy can be transferred to the surface of the photocatalytic material and mineralize the macromolecular organic matter near the active center into harmless substances, or they can recombine and dissipate energy. The present invention combines a microreactor with a high specific surface area and a small characteristic length with a photocatalyst. The photocatalytic microreactor thus developed not only has a large specific surface area, fully optimizes the distribution of light inside the microreactor, but also strengthens the mass transfer between phases. The removal capacity of total nitrogen and total phosphorus can be improved, and the effluent water quality is better than the Class A standard of the "Comprehensive Sewage Discharge Standard (GB8978-1996)". BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a process for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp according to the present invention;

[0027] Figure 2 It is a structural schematic diagram of the microchannel reaction tube in the present invention;

[0028] Figure 3The morphology of graphene-modified aerogel porous material observed by scanning electron microscope;

[0029] Figure 4 This is a scanning electron microscope observation of the surface of the aerogel porous material skeleton coated with polydopamine;

[0030] In the figure: 1. Wastewater regulating tank; 2. Lifting pump; 3. Hydrolysis acidification tank; 4. First submersible mixer; 5. Primary aerobic tank; 6. Aeration system; 7. Anoxic tank; 8. Second submersible mixer; 9. Secondary aerobic tank; 10. MBR membrane tank; 11. MBR membrane assembly; 12. Membrane suction pump; 13. Sludge return pump; 14. Nitration liquid return pump; 15. Microchannel reactor treatment tank; 16. Microchannel reactor module; 17. Microchannel reaction tube; 18. Ultraviolet lamp; 19. Closed mouth; 20. Outer tube; 21. Inner tube; 22. Closed ring cavity; 23. Light introduction cavity; 24. Aerogel porous material; 25. Water inlet hole; 26. Water outlet hole. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0032] A method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp comprises the following steps:

[0033] Step 1: connecting the wastewater regulating tank 1 to the hydrolysis acidification tank 3 via a lifting pump 2, and a first submersible mixer 4 is arranged in the hydrolysis acidification tank 3;

[0034] Step 2: Allow the water flowing out of the hydrolysis acidification tank 3 to flow into the primary aerobic tank 5 by itself, and an aeration system 6 is provided in the primary aerobic tank 5;

[0035] Step 3: Allow the water flowing out of the primary aerobic pool 5 to flow into the anoxic pool 7 by itself, and a second submersible mixer 8 is provided in the anoxic pool 7;

[0036] Step 4: The water flowing out of the anoxic tank 7 flows into the secondary aerobic tank 9 by itself, and the aeration system 6 is arranged in the secondary aerobic tank 9; the water flowing out of the secondary aerobic tank 9 flows into the MBR membrane tank 10 by itself, and the MBR membrane assembly 11 is arranged in the MBR membrane tank 10, and is pumped through the outlet of the MBR membrane assembly 11 by the membrane suction pump 12 to the microchannel reactor treatment tank 15;

[0037] Step 5: A sludge return pump 13 is provided at the lower part of the MBR membrane tank 10, and the sludge is returned to the primary aerobic tank 5 through a pipeline, and part of the remaining sludge is discharged through a sludge discharge pipeline. A nitrification liquid return pump 14 is provided at the lower part of the anoxic tank 7, and the nitrification liquid is returned to the hydrolysis acidification tank through a pipeline.

[0038] A plurality of microchannel reactor modules 16 are provided in the microchannel reactor treatment tank 15, and the sewage flows through the microchannel reactor modules 16 to photocatalytically degrade the organic sewage; after passing through the aforementioned hydrolysis acidification tank 3, primary aerobic tank 5, anoxic tank 7, secondary aerobic tank 9 and MBR membrane tank 10, most of the organic matter in the wastewater is separated and purified; however, the wastewater still contains some untreated organic matter. In this embodiment, the microchannel reactor module 16 is provided to improve the long-term operation stability of the system and to improve the performance of photocatalytic degradation of organic wastewater at a higher wastewater flow rate.

[0039] The microchannel reactor module 16 includes a microchannel reaction tube 17 and an ultraviolet lamp 18. Figure 1 As shown, the number of microchannel reactor modules 16 can be increased or decreased in the microchannel reactor treatment tank 15 according to the required treatment amount, so the device has flexible assembly, and the number of modules can be increased or decreased according to the amount of wastewater to be treated, and the modules are arranged in parallel; specifically, each of the microchannel reactor modules 16 is arranged in a matrix and has a plurality of microchannel reaction tubes 17 arranged in parallel, such as Figure 2 Shown is a schematic diagram of a microchannel reactor module 16, Figure 2Only two adjacent microchannel reaction tubes 17 are shown schematically. The microchannel reaction tube 17 is a cylindrical tubular structure with a closed opening 19 at the lower end. In actual use, the lower part of the module is completely immersed in the microchannel reactor treatment tank 15, and the closed opening 19 at the lower end blocks the wastewater from entering the light introduction cavity 23. The microchannel reactor tube with a cylindrical tubular structure includes a coaxially arranged outer tube 20 and an inner tube 21, and an annular closed ring cavity 22 is formed between the outer tube 20 and the inner tube 21. The inner tube 21 forms a light introduction cavity 23. The closed ring cavity 22 is provided with an aerogel porous material 24 modified with graphene, and the aerogel porous material 24 is modified with PDA / TiO2 / AgCl / Ag to form a photocatalytic material; the photocatalytic material is filled in the closed ring cavity 22 until The inner tube 21 is made of transparent material. In actual use, the upper mouth of the microchannel reaction tube 17 can be made of light-transmitting material, so that natural light can be irradiated into the light introduction cavity 23. In actual use, it is not easy to directly irradiate sunlight into the light introduction cavity 23 under natural conditions, and the irradiation time is short. In order to solve this problem, an artificial light source or a natural light source can be introduced into the light introduction cavity 23 by using an ultraviolet lamp 18. The interior of the light introduction cavity 23 is connected to the outside atmosphere. The outer wall of the lower end of the outer tube 20 is provided with a water inlet hole 25 connected to the closed ring cavity 22, and the upper end of the microchannel reaction tube 17 is provided with a water outlet hole 26; therefore, the water inlet hole 25 can press the wastewater into the water inlet hole 25 by using the pressure generated by the liquid level height of the wastewater in the microchannel reactor treatment tank 15, such as Figure 2 As shown, the upper ends of the various microchannel reaction tubes 17 are connected in parallel, and negative pressure is generated in the main pipe. In actual use, a water pump can be used to generate negative pressure to provide a driving force for liquid flow in the microchannel reaction tubes 17, so that wastewater is sucked in from the water inlet 25 and catalytically degraded by the photocatalytic material on organic matter, and finally flows out through the water outlet 26. The water outlets 26 of several microchannel reaction tubes 17 converge into the middle water pool; as another embodiment, the negative pressure can also be formed by a vacuum pump, and the wastewater flows through the microchannel reaction tubes 17 in the same way.

[0040] In this step, the graphene-modified aerogel porous material 24 is prepared by an acid-base two-step sol-gel method; silica aerogel is an amorphous solid material with a porous three-dimensional network structure, and has excellent physical properties, such as large specific surface area, low density, high porosity and low thermal conductivity. The fragility of the aerogel framework originates from the fragility of the inter-particle connection region, which is formed by the condensation and reprecipitation of silica particles during gelation and aging; in order to improve the mechanical properties of the aerogel and avoid network shrinkage; it is modified by graphene oxide.

[0041] Graphene oxide (GO) is an ideal nanofiller due to its unique two-dimensional structure and excellent properties.

[0042] Compared with graphene, GO contains a large number of oxygen-containing groups on its surface, which is easy to disperse evenly in common solvents. In addition, the thermal conductivity of GO is relatively low and will not adversely affect the thermal conductivity of silica aerogel. Adding GO can reduce the shrinkage of silica wet gel and enhance the mechanical strength. There is good compatibility between the two elements.

[0043] Specifically: In the first step, EtOH (ethanol), TEOS (ethyl silicate) and an appropriate amount of hydrochloric acid in a volume ratio of 30:1 are mixed to form a precursor solution, and the pH value of the mixed solution is 3-4, and then stirred at room temperature for 90 minutes; in the second step, a certain amount of graphene oxide powder, with a mass fraction of GO of 1%, is dissolved in ethanol; then the dispersed GO sheets are ultrasonically peeled for 1 hour to obtain a GO aqueous dispersion; different masses of GO solution are added to the precursor solution to obtain a doped sol with a GO content ranging from a mass fraction of 1%.

[0044] After magnetic stirring for 12 hours, 1 mol / L ammonia water was added to the pure SiO2 sol and GO / SiO2 sol until the pH value reached 6-7 while being fully hydrolyzed and evenly dispersed. To avoid precipitation of GO powder, the amount of ammonia was controlled to keep the gel time within 10 minutes. The sol was poured into a mold and, after aging at room temperature, the wet gel was placed in an ethanol bath at room temperature to remove residual impurities or moisture. Finally, GO / SiO2 aerogel was obtained by supercritical CO2 drying. Specifically, when the volume ratio of EtOH / TEOS in the precursor solution was 30:1, the GO mass fractions of the prepared aerogels were 1%.

[0045] Furthermore, the photocatalytic material is prepared in the following manner:

[0046] Modification of aerogel porous materials 24 by polydopamine (PDA)

[0047] The morphology of the graphene-modified aerogel porous material 24 was observed by scanning electron microscopy. Figure 3 As shown, it can be found that the surface of its skeleton is relatively smooth. The porous material is improved by polydopamine. PDA can be used as an adhesive coating to make the surface of the porous material rough, which is convenient for the subsequent coating of the material when the aerogel surface is modified. The adhesion and reducing properties of PDA can be used to firmly load the photocatalytic material onto the porous material carrier.

[0048] The aerogel porous material 24 was ultrasonically treated in anhydrous ethanol for 20 minutes, and then the sponge was washed with deionized water for multiple times for subsequent surface modification; the washed aerogel porous material 24 was immersed in 8L of dopamine hydrochloride aqueous solution (2.0 mg / mL), and then 2L of tris(hydroxymethyl)aminomethane aqueous solution (3.0 mg / mL) was added to the reaction system to make the pH of the aqueous solution = 8.5, and stirred for 24 hours; finally, the obtained modified material was rinsed with other substances on the surface under deionized water, and dried at 60°C, which was recorded as aerogel / PDA; Figure 4 As shown, the surface of the porous skeleton was coated with polydopamine, and it can be easily observed that the surface of the porous skeleton became rough, indicating that the polydopamine film was successfully formed on the surface of the skeleton.

[0049] The surface plasmon resonance (SPR) effect of Ag enables them to fully absorb visible light and ultraviolet light in sunlight. However, when Ag / AgCl is used alone as a catalyst, its adsorption capacity is poor. Ag / AgCl can promote the transfer of photogenerated carriers with the assistance of TiO2, which enables it to maintain its stability and photocatalytic properties. This greatly promotes the separation of electron holes in semiconductors and provides more electrons for photocatalytic reactions.

[0050] The photocatalytic microreactor exhibits a relatively high surface area to volume ratio due to its small reaction channel, reduces the molecular transmission distance, and enhances mass transfer, thereby having a better effect in purifying organic wastewater. The reaction rate of the microreactor in this embodiment is more than 100 times faster than that of an ordinary large reactor. The microchannel reaction tube 17 in this embodiment has the advantages of large surface area, simple manufacturing process, and good mass transfer effect.

[0051] Specifically, after the porous material is modified by using PDA, TiO2, AgCl, and Ag are coated on the porous material to form a porous material coated with a photocatalyst.

[0052] Preparation of TiO2 modified aerogel porous material 24

[0053] Ammonium fluorotitanate and boric acid were dissolved in deionized water, and the mass ratio of ammonium fluorotitanate: boric acid: deionized water was 1:1:100. Specifically, 100 g of ammonium fluorotitanate and 100 g of boric acid were dissolved in 10 L of deionized water. Then, the aerogel / PDA was immersed in the mixed solution and continuously oscillated at 40°C for 4 hours. Finally, the prepared TiO2-modified aerogel porous material 24 was washed with deionized water for several times and dried at 80°C for subsequent experiments, which was recorded as aerogel / PDA / TiO2.

[0054] Preparation of TiO2 / AgCl / Ag modified aerogel porous material 24

[0055] In order to prepare the PDA / TiO2 / AgCl / Ag modified aerogel porous material 24, the prepared aerogel / PDA / TiO2 aerogel porous material 24 was soaked in a 0.9wt% silver nitrate aqueous solution for 30 minutes, and then zinc chloride was added to the solution, the mass ratio of zinc chloride to silver nitrate was 0.3-0.4:1, and gently stirred for 30 minutes. Then, the sample was reduced with a xenon lamp for 30 minutes to form Ag / AgCl in situ on the surface of aerogel / PDA / TiO2: the prepared PDA / TiO2 / AgCl / Ag modified aerogel porous material 24 was rinsed with deionized water and dried overnight in a vacuum, and recorded as aerogel / PDA / TiO2 / AgCl / Ag.

[0056] The microchannel reaction tube 17 can be made of inorganic transparent materials such as silicate glass, or organic transparent materials such as acrylic, PET, PP, PVC, etc., which can transmit light well. The overall structure is as follows: Figure 2 As shown, a cylindrical structure made of transparent material introduces a light source into the internal light introduction cavity 23, and an aerogel porous material 24 coated with a photocatalyst is arranged in the closed ring cavity 22, so that a microchannel is formed in the closed ring cavity 22. Wastewater passes through the aerogel porous material 24 coated with a photocatalyst, and under the irradiation of the light source, the wastewater flows evenly through the photocatalyst, so that the organic matter in the wastewater is degraded.

[0057] According to the test, the wastewater treatment capacity of a single microchannel reaction tube 17 in this embodiment can reach 312.5 L / h•m 2 The reaction tube can be used stably for a long time and is easy to assemble. The modular design allows for flexible addition and subtraction of modules according to the required processing flow.

[0058] 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 organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp, characterized in that: include: The MBR membrane components in the membrane pool pump water to the microchannel reactor treatment pool through a membrane suction pump; the microchannel reactor treatment pool is equipped with a number of microchannel reactor modules, and the sewage flows through the microchannel reactor modules to photocatalytically degrade the organic sewage; The microchannel reactor module comprises a microchannel reaction tube and an ultraviolet lamp; each of the microchannel reactor modules is arranged in a matrix and has a plurality of microchannel reaction tubes arranged in parallel, the microchannel reaction tube is a cylindrical tubular structure, and its lower end is a closed mouth, the microchannel reactor tube of the cylindrical tubular structure comprises a coaxially arranged outer tube and an inner tube, at least the inner tube is made of a transparent material, an annular closed ring cavity is formed between the outer tube and the inner tube, a light introduction cavity is formed inside the inner tube, an aerogel porous material modified with graphene is arranged in the closed ring cavity, and the aerogel porous material is modified with PDA / TiO2 / AgCl / Ag to form a photocatalytic material; the closed ring cavity is filled with photocatalytic material, the outer wall of the lower end of the outer tube is provided with a water inlet hole connected to the closed ring cavity, and the upper end of the microchannel reaction tube is provided with a water outlet hole.

2. The method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp according to claim 1, characterized in that: The graphene-modified aerogel porous material is prepared by an acid-base two-step sol-gel method; In the first step, EtOH, TEOS and an appropriate amount of hydrochloric acid in a volume ratio of 30:1 are mixed to form a precursor solution, the pH value of the mixed solution is 3-4, and then stirred at room temperature for 90 minutes; in the second step, graphene oxide powder is dissolved in ethanol; then the dispersed GO sheets are ultrasonically peeled for 1 hour to obtain a GO aqueous dispersion; GO solution is added to the precursor solution to obtain a GO-doped sol; After magnetic stirring for 12 h, 1 mol / L ammonia water was added to the pure SiO2 sol and GO / SiO2 sol until the pH value reached 6-7 while being fully hydrolyzed and evenly dispersed. The sol was poured into a mold and aged at room temperature. The wet gel was placed in an ethanol bath at room temperature to remove any residual impurities or moisture. GO / SiO2 aerogel was obtained by supercritical CO2 drying.

3. A method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp according to claim 1 or 2, characterized in that: The photocatalytic material is prepared in the following manner: Modification of aerogel porous materials by polydopamine (PDA): The aerogel porous material was ultrasonically washed in anhydrous ethanol; the washed aerogel porous material was immersed in an aqueous solution of dopamine hydrochloride, and then an aqueous solution of tris(hydroxymethyl)aminomethane was added to the reaction system to make the pH of the aqueous solution equal to 8.5, and stirred for 24 hours; finally, the obtained modified material was rinsed with other substances on the surface under deionized water, and dried at 60°C, which was recorded as aerogel / PDA; Preparation of TiO2 modified aerogel porous materials: Ammonium fluorotitanate and boric acid were dissolved in deionized water with a mass ratio of ammonium fluorotitanate: boric acid: deionized water = 1:1:100; then the aerogel / PDA was immersed in the mixed solution and continuously oscillated at 40°C for 4 hours; finally, the prepared TiO2-modified aerogel porous material was washed with deionized water for several times and dried at 80°C for subsequent experiments, which was recorded as aerogel / PDA / TiO2; Preparation of TiO2 / AgCl / Ag modified aerogel porous materials: In order to prepare PDA / TiO2 / AgCl / Ag modified aerogel porous material, the prepared aerogel / PDA / TiO2 aerogel porous material was soaked in a 0.9wt% silver nitrate aqueous solution for 30 minutes, and then zinc chloride was added to the solution, the mass ratio of zinc chloride to silver nitrate was 0.3-0.4:1, and gently stirred for 30 minutes. Then, the sample was reduced with a xenon lamp for 30 minutes to in situ form Ag / AgCl on the surface of aerogel / PDA / TiO2: the prepared PDA / TiO2 / AgCl / Ag modified aerogel porous material was rinsed with deionized water and dried in vacuum overnight, and was recorded as aerogel / PDA / TiO2 / AgCl / Ag.

4. The method for treating organic wastewater using a graphene aerogel microchannel reactor and an ultraviolet lamp according to claim 3, characterized in that: Before the step of allowing the supernatant to flow to the microchannel reactor treatment tank by gravity, the following steps are also included: Step 1: connecting the wastewater regulating tank to the hydrolysis acidification tank via a lifting pump, and providing a first submersible mixer in the hydrolysis acidification tank; Step 2: Allow the water flowing out of the hydrolysis acidification tank to flow into the primary aerobic tank by itself, and an aeration system is provided in the primary aerobic tank; Step 3: Allow the water flowing out of the primary aerobic pool to flow into the anoxic pool by itself, and a second submersible mixer is provided in the anoxic pool; Step 4: the water flowing out of the anoxic tank flows into the secondary aerobic tank by itself, and the secondary aerobic tank is provided with an aeration system; the water flowing out of the secondary aerobic tank flows into the MBR membrane tank by itself, and the MBR membrane assembly is provided in the MBR membrane tank, and the water is pumped into the microchannel reactor treatment tank through the outlet of the MBR membrane assembly by a membrane suction pump; Step 5: A sludge return pump is installed at the bottom of the MBR membrane tank, and the sludge is returned to the primary aerobic tank through the pipeline. Some of the remaining sludge is discharged through the sludge discharge pipeline. A nitrification liquid return pump is installed at the bottom of the anoxic tank, and the nitrification liquid is returned to the hydrolysis acidification tank through the pipeline.

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