A tertiary sewage treatment device and an environment-friendly and efficient sewage treatment method for treating sewage containing multiple complex pollutants

Abstract

A kind of tertiary sewage treatment device for treating sewage containing multiple complex pollutants and an efficient sewage treatment method, which belongs to the technical field of sewage treatment.The present application aims to solve the problem that the existing water treatment device cannot flexibly treat wastewater containing multiple complex pollutants, is not resistant to high-viscosity oil pollution, cannot be sterilized, and has low pollutant recovery rate and is difficult to recycle as resources.A kind of tertiary sewage treatment device for treating sewage containing multiple complex pollutants, comprising an oil-water separation part, a disinfection and sterilization part and an ultrafiltration part.Method: I, sewage is filtered through the oil-water separation part using a primary modified microfiltration membrane;the sewage from which large oil particles are removed is allowed to stand in the disinfection and sterilization part and sterilized using a secondary modified zinc foil;III, the sterilized sewage is filtered through the ultrafiltration part using a tertiary modified filtration ultrafiltration membrane.The present application is suitable for treating sewage containing multiple complex pollutants.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to a three-stage sewage treatment device for treating sewage containing multiple complex pollutants and an environment-friendly and efficient sewage treatment method. BACKGROUND

[0002] With the progress of society and the advancement of industrialization, environmental pollution problems are increasingly serious and threaten the living environment of human beings, among which water pollution problems are particularly prominent. Domestic wastewater and industrial wastewater are important sources of water pollution. These wastewaters often contain a large amount of oil, protein, bacteria and other substances. Direct discharge of these wastewaters containing multiple complex pollutants will cause serious water pollution and exacerbate the water resource crisis. Therefore, efficient treatment of these wastewaters containing a large amount of oil, protein, bacteria and other pollutants has attracted more and more attention from researchers and has gradually become an important research field involving environmental, economic and social issues. However, due to the complexity of such sewage, the existing sewage treatment technology has problems such as unsatisfactory separation performance in the water treatment process, intolerance to high-viscosity oil pollution, inability to sterilize, low pollutant recovery rate and difficulty in resource recycling, so it cannot flexibly treat sewage containing multiple complex pollutants. SUMMARY

[0003] The present application aims to solve the problems of the existing water treatment device, such as inability to flexibly treat wastewater containing complex and multiple pollutants, intolerance to high-viscosity oil pollution, inability to sterilize, low pollutant recovery rate and difficulty in resource recycling, and to provide a three-stage sewage treatment device for treating wastewater containing multiple complex pollutants and an environment-friendly and efficient sewage treatment method.

[0004] A three-stage sewage treatment device for treating wastewater containing multiple complex pollutants, comprising an oil-water separation part, a disinfection and sterilization part and an ultrafiltration part.

[0005] The water outlet of the oil-water separation part is connected to the water inlet of the disinfection and sterilization part through a first water outlet pipe, the water outlet of the disinfection and sterilization part is connected to the water inlet of the ultrafiltration part through a second water outlet pipe, and the water outlet of the ultrafiltration part is connected to a water tank 4 through a third water outlet pipe.

[0006] The oil-water separation part is a filter device, and a primary modified microfiltration membrane 1 is arranged in the filter device.

[0007] The disinfection and sterilization part is a barrel-shaped rotary sterilization device, and a secondary modified zinc foil 2 is arranged in the barrel-shaped rotary sterilization device.

[0008] The ultrafiltration part is a driven cup-shaped filter device, and a tertiary modified filtration ultrafiltration membrane 3 is arranged in the driven cup-shaped filter device.

[0009] The application discloses a method for treating sewage containing multiple complex pollutants by using a three-stage sewage treatment device.

[0010] I. The sewage is filtered by a first modified microfiltration membrane 1 in an oil-water separation part to obtain sewage from which large-particle oil is removed;

[0011] The filtration flow of the first modified microfiltration membrane 1 in step one is 500 L / h to 1000 L / h;

[0012] II. The sewage from which large-particle oil is removed is placed in a disinfection part for 0.5 h to 1 h and then sterilized by a second modified zinc foil 2 to obtain sterilized sewage;

[0013] III. The sterilized sewage is filtered by a third modified filtration ultrafiltration membrane 3 in an ultrafiltration part to obtain treated sewage meeting discharge standards and stored in a water tank 4;

[0014] The filtration flow of the third modified filtration ultrafiltration membrane 3 in step III is 300 L / h to 500 L / h.

[0015] Principle of the application:

[0016] 1. Firstly, a large number of phenolic hydroxyl groups in caffeic acid are oxidized into quinone groups in a weak alkaline Tris-HCl solution, and meanwhile, gamma-aminopropyl triethoxysilane molecules are hydrolyzed and condensed into a structure containing silicon hydroxyl groups in the Tris-HCl solution; at this time, Michael addition reaction and Schiff base reaction occur between the caffeic acid and the gamma-aminopropyl triethoxysilane, a cross-linked network structure is formed, and hybrid nanoparticles with uniform sizes are coated on the surface of a polyvinylidene fluoride membrane;

[0017] 2. Zinc nitrate and potassium hydroxide generate a nitric acid reaction, and the formula is as follows: 2K(NO3) + Zn(OH)2 is generated;

[0018] Zn(NO3)2 + 2KOH -> 2K(NO3) + Zn(OH)2;

[0019] 3. Polyvinylidene fluoride is used as a film-forming base material, and silica microspheres are used for increasing the hydrophilicity of the membrane surface; the size of the membrane pores can be accurately controlled by adjusting the content of a pore-forming agent; the blended solution of the three is scraped into a 200 mu m-thick flat plate membrane according to a non-solvent induced phase separation method; there is no chemical reaction between them, and the three are blended into a membrane;

[0020] 4、The present application provides a kind of tertiary sewage treatment device containing multiple complex pollutants, and utilize its hierarchical purification wastewater;The present application solves the bottleneck that the existing sewage treatment process can only treat the sewage containing specific one kind of pollutants, and the present application can be different according to the type of pollutants in wastewater and grade sewage treatment, guarantee the flexibility of sewage treatment process, and the primary filtration modified microfiltration membrane 1 in the present application has ultra-high permeation flux in retaining crude oil and tertiary modified filtration ultrafiltration membrane 3 retains protein and other substances, fine separation efficiency, strong anti-pollution, low energy consumption, can greatly extend the service life of membrane, reduce use cost;Secondary modified zinc foil 2 can kill bacteria in a short time, with short-time high-efficiency bactericidal property.

[0021] The beneficial effects of the present application are as follows:

[0022] The tertiary sewage treatment device containing multiple complex pollutants in the present application can grade different pollutants to achieve the purpose of purifying wastewater, compared with the general wastewater separation device process, the tertiary environmental protection efficient sewage treatment device of the present application can grade different pollutants and can be built according to the composition of wastewater containing different pollutants The appropriate tertiary environmental protection efficient sewage treatment station device is flexible and suitable for wastewater treatment to achieve the most economical and best treatment effect.

[0023] The present application is suitable for treating sewage containing multiple pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The structure diagram of the tertiary sewage treatment device containing multiple complex pollutants described in embodiment 1 is shown in the figure.

[0025] Figure 2 The C1s XPS spectrum of the surface of the primary filtration modified microfiltration membrane prepared in embodiment 1 is shown in the figure.

[0026] Figure 3 The electron microscope photo of the surface of the unmodified polyvinylidene fluoride microporous filter membrane is shown in the figure.

[0027] Figure 4 The electron microscope photo of the surface of the polyvinylidene fluoride microporous filter membrane coated with coffee acid in control example 1 is shown in the figure.

[0028] Figure 5 The surface electron microscope photo of the primary filtration modified microfiltration membrane obtained by co-coating polyvinylidene fluoride with coffee acid and gamma-aminopropyl triethoxysilane in embodiment 1 is shown in the figure.

[0029] Figure 6 The filtration performance test results of the primary filtration modified microfiltration membrane obtained by co-coating polyvinylidene fluoride with coffee acid and gamma-aminopropyl triethoxysilane in embodiment 1 are shown in the figure.

[0030] Figure 7 SEM photos of the primary filtration modified microfiltration membrane obtained from polyvinylidene fluoride co-coated with caffeic acid and γ-aminopropyl triethoxysilane in Example 2;

[0031] Figure 8 Filtering performance test results of the primary filtration modified microfiltration membrane obtained from polyvinylidene fluoride co-coated with caffeic acid and γ-aminopropyl triethoxysilane in Example 2;

[0032] Figure 9 SEM photos of the unmodified zinc foil substrate in Example 1;

[0033] Figure 10 Bactericidal effect of the secondary modified zinc foil in Example 1;

[0034] Figure 11 SEM photos of the polyvinylidene fluoride ultrafiltration base membrane in Example 1;

[0035] Figure 12 SEM photos of the tertiary modified filtration ultrafiltration membrane in Example 1;

[0036] Figure 13 Filtering performance of the tertiary modified filtration ultrafiltration membrane in Example 1. DETAILED DESCRIPTION

[0037] Specific embodiment one: a tertiary sewage treatment device for treating sewage containing multiple complex pollutants, comprising an oil-water separation part, a disinfection and sterilization part, and an ultrafiltration part;

[0038] The water outlet of the oil-water separation part is connected to the water inlet of the disinfection and sterilization part through a first water outlet pipe, the water outlet of the disinfection and sterilization part is connected to the water inlet of the ultrafiltration part through a second water outlet pipe, and the water outlet of the ultrafiltration part is connected to the water tank 4 through a third water outlet pipe;

[0039] The oil-water separation part is a filtration device, and a primary filtration modified microfiltration membrane 1 is arranged in the filtration device;

[0040] The disinfection and sterilization part is a cylindrical rotary sterilization device, and a secondary modified zinc foil 2 is arranged in the cylindrical rotary sterilization device;

[0041] The ultrafiltration part is a driven cup-shaped filtration device, and a tertiary modified filtration ultrafiltration membrane 3 is arranged in the driven cup-shaped filtration device.

[0042] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the preparation method of the primary filtration modified microfiltration membrane 1 is as follows:

[0043] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for a period of time, and after being taken out, dried to obtain a primary filtration modified microfiltration membrane 1;

[0044] The concentration of caffeic acid in the Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane is 2 g / L, and the concentration of γ-aminopropyl triethoxysilane is 1 g / L to 4 g / L. The other steps are the same as in the first embodiment.

[0045] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for a period of time, and after being taken out, dried to obtain a primary filtration modified microfiltration membrane 1;

[0046] The concentration of caffeic acid in the Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane is 2 g / L, and the concentration of γ-aminopropyl triethoxysilane is 1 g / L to 4 g / L. The other steps are the same as in the first embodiment.

[0047] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for a period of time, and after being taken out, dried to obtain a primary filtration modified microfiltration membrane 1;

[0048] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for a period of time, and after being taken out, dried to obtain a primary filtration modified microfiltration membrane 1;

[0049] The concentration of caffeic acid in the Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane is 2 g / L, and the concentration of γ-aminopropyl triethoxysilane is 1 g / L to 4 g / L. The other steps are the same as in the first embodiment.

[0050] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for a period of time, and after being taken out, dried to obtain a primary filtration modified microfiltration membrane 1;

[0051] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for a period of time, and after being taken out, dried to obtain a primary filtration modified microfiltration membrane 1;

[0052] Specific embodiment eight: the difference between this embodiment and one of the specific embodiments one to seven is that the preparation method of the tertiary modified filtration ultrafiltration membrane 3 is completed according to the following steps:

[0053] (1) Disperse the pore-forming agent, monodisperse silica microspheres and polyvinylidene fluoride powder into N,N-dimethylformamide, then heat the mixed solution to 70-75°C and continuously stir for 8-10h to form a uniform casting solution;

[0054] The mass fraction of monodisperse silica microspheres in the casting solution in step (1) is 0.2%-0.5%, the mass fraction of polyvinylidene fluoride is 16%-20%, and the mass fraction of the pore-forming agent is 0.5%-2%;

[0055] The pore-forming agent in step (1) is polypyrrolidone;

[0056] The monodisperse silica microspheres in step (1) are prepared by sol-gel method and have a diameter of 200-500μm;

[0057] (2) Cool the casting solution to room temperature and let it stand for deaeration to obtain a deaerated casting solution;

[0058] The deaeration time in step (2) is 8-10h;

[0059] (3) Use a doctor blade to coat the deaerated casting solution on a clean glass plate to a thickness of 200μm, pre-convert in air for 30-35s, then place the glass plate in a room temperature coagulation bath for phase inversion;

[0060] The coagulation bath in step (3) is water; the phase inversion time is 20-24h;

[0061] (4) After the membrane is separated from the glass plate, obtain the tertiary modified filtration ultrafiltration membrane 3, which is continuously stored in the coagulation bath for 24h before use;

[0062] The coagulation bath in step (4) is water. The other steps are the same as in specific embodiments one to seven.

[0063] Specific embodiment nine: this embodiment uses a method for treating tertiary sewage containing various complex pollutants using an environmentally friendly and efficient sewage treatment device, which is completed according to the following steps:

[0064] I. The sewage is subjected to an oil-water separation part and filtered by a primary filtration modified microfiltration membrane 1 to obtain sewage with large particle oil removed;

[0065] ​The filtration flow of the primary modified microfiltration membrane 1 in step one is 500L / h-1000L / h;

[0066] II. The sewage with removed large particle oil is placed in the disinfection and sterilization part for 0.5-1h, and sterilized by the secondary modified zinc foil 2 to obtain sterilized sewage;

[0067] III. The sterilized sewage is filtered by the tertiary modified filtration ultrafiltration membrane 3 in the ultrafiltration part to obtain treated water meeting the discharge standard, which is stored in the water tank 4;

[0068] The filtration flow of the tertiary modified filtration ultrafiltration membrane 3 in step three is 300L / h-500L / h.

[0069] Specific implementation ten: the difference between this embodiment and one of the specific implementations one to nine is that the concentration of crude oil in the sewage in step one is 10g / L-50g / L, the concentration of bovine serum albumin is 1g / L-3g / L, and the concentration of bacteria is 10 4 CFU / mL -1 -3x10 4 CFU / mL -1 ; the concentration of crude oil in the treated water meeting the discharge standard in step three is 50mg / L-100mg / L, the concentration of bovine serum albumin is 0g / L-3mg / L, and the concentration of bacteria is 10 -1 CFU / mL -1 -100CFU / mL ; the size of the crude oil is 100nm-10μm, the size of the bovine serum albumin is 67KDa, and the size of the bacteria is 0.5μm-5μm. The other steps are the same as those in the specific implementations one to nine.

[0070] The beneficial effects of the present application are verified by the following examples:

[0071] Example 1: a tertiary sewage treatment device for treating sewage containing various complex pollutants, comprising an oil-water separation part, a disinfection and sterilization part, and an ultrafiltration part;

[0072] The water outlet of the oil-water separation part is connected to the water inlet of the disinfection and sterilization part through a first water outlet pipe, the water outlet of the disinfection and sterilization part is connected to the water inlet of the ultrafiltration part through a second water outlet pipe, and the water outlet of the ultrafiltration part is connected to the water tank 4 through a third water outlet pipe;

[0073] The oil-water separation part is a filtration device, and a primary modified microfiltration membrane 1 is arranged in the filtration device;

[0074] The disinfection and sterilization part is a cylindrical rotary sterilization device, and a secondary modified zinc foil 2 is arranged in the cylindrical rotary sterilization device;

[0075] The ultrafiltration part is a driving cup-shaped filter device, and the driving cup-shaped filter device is provided with a three-stage modified filter ultrafiltration membrane 3.

[0076] The preparation method of the first-stage filter modified microfiltration membrane 1 is specifically completed by the following steps:

[0077] The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane for 12 h, and after being taken out, it is dried at 60 ℃ for 3 h to obtain the first-stage filter modified microfiltration membrane 1;

[0078] The concentration of caffeic acid in the Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane is 2 g / L, and the concentration of γ-aminopropyl triethoxysilane is 4 g / L;

[0079] The pH value of the Tris buffer solution in the Tris-HCl buffer solution of caffeic acid and γ-aminopropyl triethoxysilane is 8.4, and the concentration is 0.1 mol / L;

[0080] The preparation method of the second-stage modified zinc foil 2 is specifically completed by the following steps:

[0081] The zinc foil is inverted and suspended in a mixed solution of zinc nitrate and potassium hydroxide at room temperature for 20 min, then washed with deionized water for 3 times, washed with anhydrous ethanol for 3 times, and finally dried with flowing nitrogen to obtain the second-stage modified zinc foil 2;

[0082] The concentration of zinc nitrate in the mixed solution of zinc nitrate and potassium hydroxide is 0.5 mol / L, and the concentration of potassium hydroxide is 4 mol / L;

[0083] The preparation method of the third-stage modified filter ultrafiltration membrane 3 is specifically completed by the following steps:

[0084] (1) Disperse the pore-forming agent, monodisperse silica microspheres and polyvinylidene fluoride powder into N,N-dimethylformamide, then heat the mixed solution to 75 ℃ and continuously stir for 10 h to form a uniform casting solution;

[0085] The mass fraction of the monodisperse silica microspheres in the casting solution in step (1) is 0.2%, the mass fraction of the polyvinylidene fluoride is 20%, and the mass fraction of the pore-forming agent is 0.5%;

[0086] The pore-forming agent in step (1) is polypyrrolidone;

[0087] The monodisperse silica microspheres in step (1) are prepared by Stǒber sol-gel method, and the diameter is 400 μm;

[0088] (2) cooling the casting solution to room temperature and standing for defoaming to obtain a defoamed casting solution;

[0089] The defoaming time in step (2) is 10 h;

[0090] (3) using a doctor blade to coat the defoamed casting solution on a clean glass plate to a thickness of 200 μm, pre-conversion in air for 30 s, and then placing the glass plate in a room temperature coagulation bath for phase inversion;

[0091] The coagulation bath in step (3) is water; and the phase inversion time is 24 h;

[0092] (4) after the membrane is separated from the glass plate, obtaining a tertiary modified filtration ultrafiltration membrane 3, which is continuously stored in the coagulation bath for 24 h before use;

[0093] The coagulation bath in step (4) is water.

[0094] Example 2: using the method for treating sewage containing multiple complex pollutants described in Example 1, which is specifically completed according to the following steps:

[0095] I. The sewage is filtered by using a primary filtration modified microfiltration membrane 1 after oil-water separation, to obtain sewage with large particle oil removed;

[0096] The concentration of crude oil in the sewage in step I is 10 g / L, the concentration of bovine serum albumin is 1 g / L, and the concentration of bacteria is 10 4 CFU mL -1 ; the size of the crude oil is 100 nm-10 μm, the size of the bovine serum albumin is 67 KDa, and the size of the bacteria is 0.5 μm-5 μm;

[0097] The filtration flow rate of the primary filtration modified microfiltration membrane 1 in step I is 500 L / h;

[0098] II. The sewage with large particle oil removed is placed in a disinfection and sterilization section for 0.5 h, and then sterilized by using a secondary modified zinc foil 2 to obtain sterilized sewage;

[0099] III. The sterilized sewage is filtered by using a tertiary modified filtration ultrafiltration membrane 3 in an ultrafiltration section to obtain treated water meeting the discharge standard, which is stored in a water tank 4;

[0100] The filtration flow rate of the tertiary modified filtration ultrafiltration membrane 3 in step III is 200 L / h.

[0101] The concentration of crude oil in the water reaching the discharge standard after the treatment described in step three of Example 2 is 50 mg / L, the concentration of bovine serum albumin is 1 mg / L, and the concentration of bacteria is 100 CFU / mL -1 .

[0102] Figure 2 C1s XPS spectrum of the surface of the primary filtration modified microfiltration membrane prepared in Example 1;

[0103] It can be seen that the C=N and C-N characteristic peaks at 286.4 and 285 eV indicate that the phenolic hydroxyl group of the caffeic acid and the amino group of the γ-aminopropyl triethoxysilane molecule undergo Michael addition and Schiff base reaction in a weak alkaline environment to generate hybrid smooth nanoparticles deposited on the surface of the microfiltration membrane, forming a preliminary rough structure to improve the hydrophilicity of the membrane surface. Figure 2 Comparative Example 1: Method for coating polyvinylidene fluoride microporous filtration membrane with caffeic acid, which is completed according to the following steps:

[0104] The polyvinylidene fluoride microporous filtration membrane is placed in a caffeic acid Tris-HCl buffer solution for 12 h, and after being taken out, it is dried at 60°C for 3 h to obtain a polyvinylidene fluoride microporous filtration membrane coated with caffeic acid;

[0105] The concentration of caffeic acid in the caffeic acid Tris-HCl buffer solution is 2 g / L;

[0106] The pH value of the Tris buffer solution in the caffeic acid Tris-HCl buffer solution is 8.4, and the concentration is 0.1 mol / L.

[0107]

[0108] The electron microscope photograph of the surface of the unmodified polyvinylidene fluoride microporous filtration membrane; Figure 3

[0109] The electron microscope photograph of the surface of the polyvinylidene fluoride microporous filtration membrane coated with caffeic acid in Comparative Example 1; Figure 4

[0110] The electron microscope photograph of the surface of the primary filtration modified microfiltration membrane obtained by coating polyvinylidene fluoride with caffeic acid and γ-aminopropyl triethoxysilane in Example 1; Figure 5 It can be seen that the unmodified membrane surface presents a smooth fiber skeleton structure, and

[0111] It is shown that although modified by caffeic acid, the morphology of the membrane surface does not change significantly, and still presents a smooth fiber skeleton structure, and Figure 3 Figure 4 It is shown that although modified by caffeic acid, the morphology of the membrane surface does not change significantly, and still presents a smooth fiber skeleton structure, and Figure 5 ​This indicates that the polyvinylidene fluoride microporous filter membrane modified by co-coating with caffeic acid and γ-aminopropyltriethoxysilane has a layered structure of nanospheres that are uniformly attached to the membrane surface without any pore blockage.

[0112] Figure 6 The results show the filtration performance of the primary filtration modified microfiltration membrane obtained by co-coating polyvinylidene fluoride with caffeic acid and γ-aminopropyltriethoxysilane in Example 1.

[0113] from Figure 6 It can be seen that this invention utilizes caffeic acid and γ-aminopropyltriethoxysilane to coat a polyvinylidene fluoride microporous filter membrane, achieving an upgrade from a highly hydrophobic microfiltration membrane to a superhydrophilic / underwater oleophobic microfiltration membrane. The prepared superhydrophilic / underwater oleophobic microfiltration membrane exhibits a rejection rate of >99% for crude oil with an average size of 1 μm, and a water permeation flux of approximately 6500 Lm. -2 h -1 bar -1 However, under pressure, some small crude oil particles enter the filtrate with the water flow in the unmodified virgin polyvinylidene fluoride microporous membrane, while some crude oil adheres to the membrane surface and blocks the membrane pores. When the crude oil blocks both the surface and the inside of the membrane pores, water cannot pass through. Therefore, the unmodified virgin membrane cannot retain crude oil with an average size of 1 μm.

[0114] In summary, compared with the unmodified polyvinylidene fluoride (PVDF) microporous filter membrane, the modification of the PVDF microporous filter membrane by caffeic acid and γ-aminopropyltriethoxysilane in this invention clearly shows the formation of a uniform selective coating layer on the surface of the PVDF microporous filter membrane. In addition, according to the long-term separation performance test results, the superhydrophilic / submarine oleophobic microfiltration membrane obtained by this invention achieves high efficiency in retaining crude oil during the test time, and the flux remains at a high level with only a slight decrease.

[0115] Example 2: The difference between this example and Example 1 is that the concentration of caffeic acid in the Tris-HCl buffer solution of caffeic acid and γ-aminopropyltriethoxysilane is 2 g / L, and the concentration of γ-aminopropyltriethoxysilane is 1 g / L. All other steps and parameters are the same as in Example 1.

[0116] Figure 7 This is a surface electron microscope image of the primary filtration modified microfiltration membrane obtained by co-coating polyvinylidene fluoride with caffeic acid and γ-aminopropyltriethoxysilane in Example 2.

[0117] from Figure 7 It can be seen that, compared with Example 1, the surface coating of the superhydrophilic / underwater oleophobic microfiltration membrane prepared in Example 2 using γ-aminopropyltriethoxysilane at 1 g / L has poor uniformity and is inconsistent, and does not completely cover the fiber skeleton on the membrane surface.

[0118] Figure 8 The results show the filtration performance of the primary filtration modified microfiltration membrane obtained by co-coating polyvinylidene fluoride with caffeic acid and γ-aminopropyltriethoxysilane in Example 2.

[0119] from Figure 8 It can be seen that, compared with Example 1, the surface coating of the superhydrophilic / underwater oleophobic microfiltration membrane prepared by using γ-aminopropyltriethoxysilane as 1 g / L in Example 2 has poor uniformity and inconsistent coating, and does not completely cover the fiber skeleton on the membrane surface. Therefore, the rejection rate of crude oil with a size of 1 μm is low, the initial flux is low and the flux decreases rapidly.

[0120] Figure 9 The image shows an electron microscope (EM) image of the unmodified zinc foil substrate from Example 1.

[0121] from Figure 9 It can be seen that the surface of the unmodified zinc foil substrate in Example 1 is rough and uneven.

[0122] Figure 10 This demonstrates the bactericidal effect of the secondary modified zinc foil in Example 1.

[0123] from Figure 10 It can be seen that: with Figure 7 In contrast, the zinc foil surface exhibits a crystalline structure of clustered, scattering nanowires.

[0124] Figure 11 The image shown is an electron microscope image of the polyvinylidene fluoride ultrafiltration membrane in Example 1.

[0125] from Figure 11 It can be seen that the surface of the polyvinylidene fluoride ultrafiltration membrane remains smooth and non-porous under a 5Kx lens.

[0126] Figure 12 The image shown is an electron microscope image of the three-stage modified ultrafiltration membrane in Example 1.

[0127] from Figure 12 It can be seen that after modification with silica nanoparticles and the addition of pore-forming agents, the chamber outlines on the membrane surface are clear, and the size of each chamber is about 1 μm. At the same time, monodisperse silica nanoparticles are distributed in each chamber, covering part of the membrane pores, which reduces the size, increases the separation performance and enhances the hydrophilicity. The average size is 0.02 μm.

[0128] Figure 13 The filtration performance of the three-stage modified ultrafiltration membrane in Example 1;

[0129] from Figure 13 It can be seen that the flux of the modified ultrafiltration filter remained at 500 μL / m³ within 120 hours of operation for separating BSA solution. -2 h-1 bar -1 The above and without substantially reducing the separation flux, the retention rate is maintained at more than 95%, indicating that the membrane has excellent ultrafiltration separation performance.

Claims

1. A method for treating sewage water containing a plurality of complex pollutants by using a tertiary sewage treatment device, characterized in that The concentration of crude oil in the sewage is 10 g / L, the concentration of bovine serum albumin is 1 g / L, and the concentration of bacteria is 10 4 CFU / mL -1 ; the size of the crude oil is 100 nm to 10 pm, the size of the bovine serum albumin is 67 KDa, and the size of the bacteria is 0.5 pm to 5 pm, and after the method is processed, the concentration of crude oil in the water is 50 mg / L, the concentration of bovine serum albumin is 1 mg / L, and the concentration of bacteria is 100 CFU / mL -1 ; The method is specifically completed by the following steps: I. The sewage is filtered by a primary filtering modified microfiltration membrane in an oil-water separation part to obtain sewage with large oil particles removed; The filtering flow rate of the primary filtering modified microfiltration membrane in step I is 500 L / h; II. The sewage with large oil particles removed is sterilized by a secondary modified zinc foil in a sterilization part for 0.5 h to obtain sterilized sewage; III. The sterilized sewage is filtered by a tertiary modified filtering ultrafiltration membrane in an ultrafiltration part to obtain treated sewage meeting the discharge standard and stored in a water tank; The filtering flow rate of the tertiary modified filtering ultrafiltration membrane in step III is 200 L / h; The tertiary sewage treatment device for treating sewage containing multiple complex pollutants comprises an oil-water separation part, a sterilization part and an ultrafiltration part; The outlet of the oil-water separation part is connected to the inlet of the sterilization part through a first outlet pipe, the outlet of the sterilization part is connected to the inlet of the ultrafiltration part through a second outlet pipe, and the outlet of the ultrafiltration part is connected to the water tank through a third outlet pipe; The oil-water separation part is a filtering device, and a primary filtering modified microfiltration membrane is arranged in the filtering device; The sterilization part is a cylindrical rotary sterilization device, and a secondary modified zinc foil is arranged in the cylindrical rotary sterilization device; The ultrafiltration part is a driving cup-shaped filtering device, and a tertiary modified filtering ultrafiltration membrane is arranged in the driving cup-shaped filtering device; The preparation method of the primary filtering modified microfiltration membrane is specifically completed by the following steps: The polyvinylidene fluoride microporous filter membrane is placed in a Tris-HCl buffer solution containing coffee acid and γ-aminopropyl triethoxysilane for 12 h, and then taken out and dried at 60°C for 3 h to obtain the primary filtering modified microfiltration membrane; The concentration of coffee acid in the Tris-HCl buffer solution containing coffee acid and γ-aminopropyl triethoxysilane is 2 g / L, and the concentration of γ-aminopropyl triethoxysilane is 4 g / L; The pH value of the Tris buffer solution in the Tris-HCl buffer solution containing coffee acid and γ-aminopropyl triethoxysilane is 8.4, and the concentration is 0.1 mol / L; The preparation method of the secondary modified zinc foil is specifically completed by the following steps: The zinc foil is inverted and suspended in a mixed solution of zinc nitrate and potassium hydroxide at room temperature for 20 min, then washed with deionized water for 3 times, washed with anhydrous ethanol for 3 times, and finally dried with flowing nitrogen to obtain the secondary modified zinc foil; The concentration of zinc nitrate in the mixed solution of zinc nitrate and potassium hydroxide is 0.5 mol / L, and the concentration of potassium hydroxide is 4 mol / L; The preparation method of the tertiary modified filtering ultrafiltration membrane is specifically completed by the following steps: (1) The pore-forming agent, monodisperse silica microspheres and polyvinylidene fluoride powder are dispersed in N,N-dimethylformamide, and then the mixed solution is heated to 75°C and continuously stirred for 10 h to form a uniform casting solution; In step (1), the mass fraction of monodisperse silica microspheres in the casting solution is 0.2%, the mass fraction of polyvinylidene fluoride is 20%, and the mass fraction of the pore-forming agent is 0.5%. The porogen in step (1) is polyparalene; The monodisperse silica microspheres in step (1) are prepared by Stober sol-gel method, and the diameter is 400 μm; (2) The casting solution is cooled to room temperature and left to stand for defoaming to obtain the defoamed casting solution; The defoaming time in step (2) is 10 h; (3) The defoamed casting solution is scraped on a clean glass plate by using a doctor blade, the thickness is controlled to be 200 μm, and the glass plate is put into a room temperature coagulation bath after pre-conversion in air for 30 s to perform phase inversion; The coagulation bath in step (3) is water; and the phase inversion time is 24 h; (4) After the membrane is separated from the glass plate, a tertiary modified filtration ultrafiltration membrane is obtained, which is continuously stored in the coagulation bath for 24 h before use; The coagulation bath in step (4) is water.

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