PTFE (Polytetrafluoroethylene) modified membrane, modification method thereof, wastewater treatment system and wastewater treatment method

Abstract

The invention provides a PTFE modified membrane, a modification method thereof, a wastewater treatment system and a wastewater treatment method, the PTFE modified membrane is obtained by adding metal oxide catalyst particles into a PTFE polymer for modification, and the weight of the metal oxide catalyst particles accounts for 5-20% of the weight of the PTFE polymer; the diameter of the metal oxide catalyst particles is 10-100 nm; the pore-forming rate of the PTFE modified membrane is 53-62%, and the pore diameter range is 0.1-1 [mu] m. The metal oxide catalyst particles are added into the PTFE polymer of the hollow fiber membrane for modification to form the PTFE modified membrane, so that the gasification catalytic effect of ozone on the surface of the membrane material of the hollow fiber membrane module is improved, and full contact, mixing and net-effect removal of pollutants and ozone are realized; therefore, the pollutant removal rate and the quality of a product produced by wastewater treatment are improved; the technological process is simple, field application is convenient, and product performance is stable.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a PTFE modified membrane and a modification method thereof, a wastewater treatment system and a treatment method. Background Art

[0002] With the rapid development of industry, the types of pollutants in wastewater are becoming increasingly complex, and the harm they cause to the environment is also increasing.

[0003] Ozone catalytic oxidation has attracted widespread attention as an effective wastewater treatment method. However, in traditional ozone catalytic oxidation processes, the contact efficiency between ozone and pollutants is low, resulting in low pollutant removal rates.

[0004] PTFE hollow fiber membranes have good chemical stability and hydrophobicity, making them suitable for wastewater treatment. However, existing hydrophobic PTFE membrane materials have limited catalytic effects and cannot meet the demand for efficient degradation of pollutants in wastewater. Summary of the Invention

[0005] In view of this, the first purpose of the present invention is to provide a PTFE modified membrane and a modification method thereof, by modifying the PTFE polymer of the hollow fiber membrane by adding metal oxide catalyst particles to form a PTFE modified membrane (strong catalytic membrane), thereby improving the catalytic effect of the hollow fiber membrane assembly, achieving sufficient contact, mixing and net removal of pollutants and ozone, and realizing efficient gasification catalysis of ozone on the surface of the membrane material, thereby improving the pollutant removal rate and the quality of wastewater treatment output products.

[0006] The second object of the present invention is to provide a wastewater treatment system and treatment method using the above-mentioned PTFE modified membrane, which has a simple process flow and is easy to apply on site.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted: The present invention provides a PTFE modified membrane. The PTFE modified membrane is obtained by adding metal oxide catalyst particles to a PTFE polymer. The weight of the metal oxide catalyst particles accounts for 5%-20% of the weight of the PTFE polymer. The diameter of the metal oxide catalyst particles is 10-100 nm (nanometers). The porosity of the PTFE modified membrane is 53-62%, and the pore size range is 0.1-1 μm (micrometers).

[0008] The present application adds nanoscale metal oxide catalyst particles (such as titanium dioxide, manganese dioxide, etc.) in PTFE polymer, which can provide greater specific surface area and improve catalytic efficiency. The metal oxide particles are uniformly dispersed in the PTFE polymer by blending method, avoiding agglomeration affecting the structure of PTFE membrane, and a PTFE modified membrane is prepared. The pore formation rate and homogeneity of the modified membrane material are studied, so that the membrane material has a suitable pore size and uniform structure, which is beneficial to the catalytic gasification of ozone on the surface of the PTFE membrane material and the sufficient contact between pollutants and ozone.

[0009] Preferably, the pore size of the PTFE modified membrane (modified high-efficiency catalytic membrane) is 0.2-0.5 μm (adapted to the diameter of ozone bubbles and the size of pollutant molecules, taking into account catalytic contact and membrane separation function).

[0010] Further, the metal oxide catalyst particles are any one of titanium dioxide catalyst particles and manganese dioxide catalyst particles. When the metal oxide catalyst particles are titanium dioxide catalyst particles, the weight of the titanium dioxide catalyst particles accounts for 5%-15% of the weight of the PTFE polymer; the diameter of the titanium dioxide catalyst particles is 10-50 nm, and the pore formation rate of the PTFE modified membrane is 58-62%.

[0011] Further, the weight of the titanium dioxide catalyst particles accounts for 10% of the weight of the PTFE polymer; the diameter of the titanium dioxide catalyst particles is 20-30 nm, and the pore formation rate of the PTFE modified membrane is 60%.

[0012] In one embodiment of the present application, by adding titanium dioxide catalyst particles in PTFE polymer, a membrane material with a pore formation rate of 60% and uniform pore size distribution is prepared, and the membrane material is processed into a hollow fiber membrane module.

[0013] Further, when the metal oxide catalyst particles are manganese dioxide catalyst particles, the weight of the manganese dioxide catalyst particles accounts for 8%-20% of the weight of the PTFE polymer; the diameter of the manganese dioxide catalyst particles is 20-100 nm, and the pore formation rate of the PTFE modified membrane is 53-57%.

[0014] Further, the weight of the manganese dioxide catalyst particles accounts for 14% of the weight of the PTFE polymer; the diameter of the manganese dioxide catalyst particles is 30-50 nm, and the pore formation rate of the PTFE modified membrane is 55%.

[0015] In another embodiment of the present invention, manganese dioxide catalyst particles are added to PTFE polymer to obtain a PTFE modified membrane having a porosity of 55% and a uniform pore size distribution. The membrane material is processed into a hollow fiber membrane module.

[0016] The present invention also provides a method for modifying a PTFE modified membrane, which is used to produce the PTFE modified membrane as described above, using a blending-phase conversion method, comprising the following steps: Mix PTFE polymer powder with a particle size of 50-100 μm with titanium dioxide or manganese dioxide catalyst particles (nanoparticles) in proportion, add organic solvent N-methylpyrrolidone or NMP, and stir at 60-80°C for 2-4 hours to form a uniform sol; The modification process first pre-treats the raw materials to form a uniform solvent to facilitate the subsequent film-forming process.

[0017] The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water phase separate to form a porous structure. The coagulation bath temperature is controlled at 0-5°C and the coagulation time is 10-20 minutes to adjust the pore size and porosity of the membrane. The present invention extrude the sol into a film through an extruder, and forms holes on the formed film by using an immersion precipitation phase conversion method; The formed membrane is heat treated at 120-150°C for 1-2 hours to eliminate the stress in the membrane and improve the mechanical strength of the membrane; then it is rinsed with deionized water 3-5 times to remove the residual solvent.

[0018] The present invention also provides a wastewater treatment system, which uses the PTFE modified membrane as described above, including: a wastewater treatment device and an ozone supply device, wherein the wastewater treatment device includes a membrane reactor, and the ozone supply device is connected to the membrane reactor; the interior of the membrane reactor is provided with a hollow fiber membrane component processed from the PTFE modified membrane and a stirring device for stirring the wastewater.

[0019] The ozone supply device is used to transport ozone into the membrane reactor. The membrane material of the PTFE modified membrane has a suitable pore size and uniform structure, which is conducive to the gasification catalysis of ozone on the surface of the membrane material and the full contact between pollutants and ozone.

[0020] Furthermore, the stirring device adopts a mechanical stirrer, and the mechanical stirrer includes a stirring shaft passing through the top of the membrane reactor and a stirring blade fixedly connected to the lower part of the stirring shaft.

[0021] Preferably, the stirring blade is a three-layer paddle blade.

[0022] The wastewater is stirred by the stirring shaft and stirring blades, and the wastewater is fully mixed with the hollow fiber membrane module and ozone through the stirring device.

[0023] The membrane reactor is provided with a water inlet for introducing wastewater into the membrane reactor and a water outlet for discharging treated wastewater from the membrane reactor. The water inlet and the water outlet are respectively provided with valves for controlling the inflow and outflow of wastewater.

[0024] Preferably, the water inlet is located at the bottom of the membrane reactor, and the wastewater enters from the bottom of the membrane reactor and passes upward through the hollow fiber membrane assembly, which helps the wastewater to fully contact with the PTFE modified membrane and improve the treatment effect; the water outlet is located at the top of the membrane reactor, and after the solid-liquid separation of the treated wastewater, the supernatant is discharged from the upper water outlet.

[0025] The present invention also provides a wastewater treatment method, which is applied to the wastewater treatment system as described above, comprising the following steps (eg Figure 1 shown): A. Introduce wastewater until the liquid level reaches the set height; Preferably, the liquid level of the wastewater is 80% of the height of the membrane reactor.

[0026] In one embodiment of the present invention, the wastewater treated is organic wastewater from a chemical plant, and the main pollutants are benzene series with a concentration of 500 mg / L.

[0027] In one embodiment of the present invention, the wastewater treated is wastewater from a printing and dyeing factory, and the main pollutant is dye with a concentration of 800 mg / L.

[0028] B. Adjust the ozone generation rate. When the metal oxide catalyst particles of the PTFE modified membrane are titanium dioxide catalyst particles, the ozone generation rate is 100 g / h. When the metal oxide catalyst particles of the PTFE modified membrane are manganese dioxide catalyst particles, the ozone generation rate is 150 g / h. Transport the ozone to contact and react with the PTFE modified membrane. A gasification catalytic reaction occurs on the surface of the PTFE modified membrane, generating free radicals with strong oxidizing properties (such as hydroxyl radicals, etc.); C. Stirring the wastewater at a stirring speed of 190-210 r / min when the metal oxide catalyst particles of the PTFE modified membrane are titanium dioxide catalyst particles, and at a stirring speed of 240-260 r / min when the metal oxide catalyst particles of the PTFE modified membrane are manganese dioxide catalyst particles; thoroughly mixing the wastewater with the PTFE modified membrane and ozone; Stirring promotes the contact and reaction between pollutants and ozone; pollutants in wastewater undergo degradation reactions under the action of ozone and free radicals, generating harmless substances or substances that are easy to handle; D. After the reaction is completed, the treated wastewater is discharged.

[0029] Preferably, during the above process, the reaction conditions in the membrane reactor, such as reaction temperature, pH value, etc., can also be controlled to optimize the effect of the ozone catalytic oxidation reaction.

[0030] For example, the temperature in the membrane reactor can be adjusted by a heating device or a cooling device, and the pH value of the wastewater can be adjusted by adding an acid-base regulator.

[0031] In an embodiment of the present invention for treating chemical plant wastewater, the chemical plant wastewater was tested before and after treatment, and the results showed that the concentration of benzene series was reduced to 50 mg / L, and the removal rate reached 90%.

[0032] In an embodiment of the present invention for treating printing and dyeing wastewater, the printing and dyeing wastewater before and after treatment was tested, and the results showed that the concentration of the dye was reduced to 80 mg / L, and the removal rate reached more than 90%.

[0033] Furthermore, when the metal oxide catalyst particles of the PTFE modified membrane are titanium dioxide catalyst particles, the reaction temperature of step B and step C is controlled at 23-27° C., the pH value is adjusted to 7.3-7.7, and the reaction time is 55-65 min; When the metal oxide catalyst particles of the PTFE modified membrane are manganese dioxide catalyst particles, the reaction temperature of step B and step C is controlled at 28-32° C., the pH value is adjusted to 7.8-8.2, and the reaction time is 85-95 min.

[0034] Compared with the prior art, the present invention has the following beneficial effects: The PTFE modified membrane and its modification method, wastewater treatment system and treatment method provided by the present invention modify the PTFE polymer of the hollow fiber membrane by adding metal oxide catalyst particles to form a PTFE modified membrane (modified strong catalytic membrane), thereby improving the gasification catalytic effect of ozone on the membrane material surface of the hollow fiber membrane assembly, achieving full contact, mixing and net removal of pollutants and ozone, thereby improving the pollutant removal rate and the quality of the wastewater treatment output product. At the same time, the provision of a stirring device can further promote the mixing of wastewater, membrane material and ozone, and improve the reaction efficiency. Controlling the reaction conditions can enable the ozone catalytic oxidation reaction to proceed under optimal conditions, further improving the treatment effect, and the process flow is simple, easy to apply on site, stable product performance, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Various other advantages and benefits will become apparent to those skilled in the art by reading the following detailed description of the preferred embodiment.The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0036] In the attached figure: Figure 1 It is a schematic flow chart of the wastewater treatment method of the present invention. DETAILED DESCRIPTION

[0037] The embodiments of the present invention will be described in detail below with reference to the examples, but those skilled in the art will appreciate that the following examples are intended only to illustrate the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0038] Example 1 1. Preparation of PTFE modified membrane: Titanium dioxide catalyst particles and PTFE polymer powder with a particle size of 50 μm were mixed at a mass ratio of 10%:1, and an organic solvent, N-methylpyrrolidone, was added and stirred at 80°C for 4 hours to form a uniform sol; The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water undergo phase separation to form a porous structure. The coagulation bath temperature is controlled at 0°C and the coagulation time is 20 minutes to adjust the pore size and porosity of the membrane. The formed membrane was heat treated at 150° C. for 2 hours to eliminate the internal stress of the membrane and improve the mechanical strength of the membrane; it was then rinsed with deionized water 5 times to remove the residual solvent.

[0039] 2. Build a wastewater treatment system: 1) A stainless steel membrane reactor with a diameter of 1m and a height of 2m was used. A PTFE-modified membrane (modified high-efficiency catalytic membrane) with a porosity of 60% and uniform pore size distribution was processed into a hollow fiber membrane module and installed in the membrane reactor.

[0040] 2) Ozone delivery pipes are evenly distributed at the bottom of the membrane reactor. Ozone generated by the ozone generator is transported to the membrane reactor through the ozone delivery pipes. Multiple ozone release holes are set on the ozone delivery pipes to evenly release ozone into the wastewater.

[0041] 3) A mechanical agitator is installed on the top of the membrane reactor, and the stirring blades are three-layer paddle blades, which are used to stir the wastewater.

[0042] 4) The bottom and top of the membrane reactor are respectively provided with an inlet and an outlet. A valve is arranged at the inlet to control the inflow of wastewater, and a valve is arranged at the outlet to control the outflow of treated wastewater.

[0043] 3. Wastewater treatment: 1) The wastewater to be treated is organic wastewater from a chemical plant, and the main pollutant is benzene series with a concentration of 500 mg / L.

[0044] 2) Open the inlet valve to introduce wastewater into the membrane reactor until the liquid level reaches 80% of the height of the membrane reactor.

[0045] 3) Start the ozone generator and adjust the ozone production to 100 g / h. The ozone is transported into the membrane reactor through the ozone delivery pipeline.

[0046] 4) Start the stirring device and set the stirring speed to 200 r / min to ensure that the wastewater is fully mixed with the modified high-efficiency catalytic membrane and ozone.

[0047] 5) The reaction temperature is controlled at 25°C, the pH value is adjusted to 7.5, and the reaction time is 60 min.

[0048] 6) After the reaction is completed, turn off the ozone generator and stirring device, and open the outlet valve to discharge the treated wastewater from the membrane reactor.

[0049] Example 2 The specific operation steps for constructing the wastewater treatment system are consistent with those of Example 1, except that the process for preparing the PTFE modified membrane is different from that of Example 1.

[0050] Mix titanium dioxide catalyst particles with PTFE polymer powder with a particle size of 50 μm at a mass ratio of 5:1, add organic solvent N-methyl pyrrolidone, stir at 60°C for 2 hours to form a uniform sol; Process the sol into a membrane sheet through an extrusion process, immerse the membrane sheet in an ice water coagulation bath, and the coagulation bath solvent and water undergo phase separation to form a porous structure; control the coagulation bath temperature at 0°C, the coagulation time at 10 minutes, and adjust the pore size and porosity of the membrane sheet; Heat treat the formed membrane sheet at 120°C for 1 hour to eliminate internal stress and improve the mechanical strength of the membrane sheet; then rinse it with deionized water for 3 times to remove residual solvents.

[0051] Example 3 The specific operation steps for constructing the wastewater treatment system are consistent with those of Example 1, except that the process for preparing the PTFE modified membrane is different from that of Example 1.

[0052] Titanium dioxide catalyst particles and PTFE polymer powder with a particle size of 50 μm were mixed at a mass ratio of 15%:1, and an organic solvent, N-methylpyrrolidone, was added and stirred at 70°C for 3 hours to form a uniform sol; The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water phase separate to form a porous structure. The coagulation bath temperature is controlled at 2.5°C and the coagulation time is 15 minutes to adjust the pore size and porosity of the membrane. The formed membrane was heat treated at 135° C. for 1.5 hours to eliminate the internal stress of the membrane and improve the mechanical strength of the membrane; it was then rinsed with deionized water four times to remove the residual solvent.

[0053] Example 4 The specific operating steps for constructing the wastewater treatment system are the same as those in Example 1, except that the metal oxide catalyst particles added to the modified strong catalytic membrane are manganese dioxide catalyst particles, the porosity is 55%, and the wastewater treatment process parameters are different.

[0054] 1. Preparation of PTFE modified membrane: Manganese dioxide catalyst particles and PTFE polymer powder with a particle size of 50 μm were mixed at a mass ratio of 20%:1, and an organic solvent, N-methylpyrrolidone, was added and stirred at 80°C for 4 hours to form a uniform sol; The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water undergo phase separation to form a porous structure. The coagulation bath temperature is controlled at 0°C and the coagulation time is 20 minutes to adjust the pore size and porosity of the membrane. The formed membrane was heat treated at 150° C. for 2 hours to eliminate the internal stress of the membrane and improve the mechanical strength of the membrane; it was then rinsed with deionized water 5 times to remove the residual solvent.

[0055] 2. Wastewater treatment: The wastewater to be treated was from a printing and dyeing plant. The main pollutant was dye, with a concentration of 800 mg / L. The reaction temperature was controlled at 30°C, the pH was adjusted to 8.0, the reaction time was 90 minutes, the ozone production was 150 g / h, and the stirring speed was 250 r / min.

[0056] Example 5 The specific operating steps for constructing the wastewater treatment system are the same as those in Example 4, except that the process for preparing the PTFE modified membrane and the process parameters for wastewater treatment are different from those in Example 4.

[0057] 1. Preparation of PTFE modified membrane: Manganese dioxide catalyst particles and PTFE polymer powder with a particle size of 50 μm were mixed at a mass ratio of 8%:1, and an organic solvent, N-methylpyrrolidone, was added and stirred at 60°C for 2 hours to form a uniform sol; The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water undergo phase separation to form a porous structure. The coagulation bath temperature is controlled at 5°C and the coagulation time is controlled at 10 minutes to adjust the pore size and porosity of the membrane. The formed membrane was heat treated at 120° C. for 1 hour to eliminate the internal stress of the membrane and improve the mechanical strength of the membrane; it was then rinsed with deionized water three times to remove the residual solvent.

[0058] 2. Wastewater treatment: The wastewater treated was from a printing and dyeing plant. The main pollutant was dye, with a concentration of 800 mg / L. The reaction temperature was controlled at 28°C, the pH was adjusted to 7.8, the reaction time was 85 minutes, the ozone production was 150 g / h, and the stirring speed was 240 r / min.

[0059] Example 6 The specific operating steps for constructing the wastewater treatment system are the same as those in Example 4, except that the process for preparing the PTFE modified membrane and the process parameters for wastewater treatment are different from those in Example 4.

[0060] 1. Preparation of PTFE modified membrane: Manganese dioxide catalyst particles and PTFE polymer powder with a particle size of 50 μm were mixed at a mass ratio of 14%:1, and an organic solvent, N-methylpyrrolidone, was added and stirred at 70°C for 3 hours to form a uniform sol; The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water phase separate to form a porous structure. The coagulation bath temperature is controlled at 2.5°C and the coagulation time is 15 minutes to adjust the pore size and porosity of the membrane. The formed membrane was heat treated at 135° C. for 1.5 hours to eliminate the internal stress of the membrane and improve the mechanical strength of the membrane; it was then rinsed with deionized water four times to remove the residual solvent.

[0061] 2. Wastewater treatment: The wastewater treated was from a printing and dyeing plant. The main pollutant was dye, with a concentration of 800 mg / L. The reaction temperature was controlled at 32°C, the pH was adjusted to 8.2, the reaction time was 95 minutes, the ozone production was 150 g / h, and the stirring speed was 260 r / min.

[0062] Example 7 The steps of preparing the PTFE modified membrane and the process and constructing the wastewater treatment system are consistent with those in Example 1, except that the specific operation steps of the wastewater treatment are different from those in Example 1.

[0063] 1) The treated wastewater is organic wastewater from a chemical plant. The main pollutants are benzene series with a concentration of 500 mg / L.

[0064] 2) Open the water inlet valve and introduce wastewater into the membrane reactor until the liquid level reaches 80% of the height of the membrane reactor.

[0065] 3) Start the ozone generator, adjust the ozone production to 100g / h, and transport the ozone to the membrane reactor through the ozone delivery pipe.

[0066] 4) Start the stirring device at a stirring speed of 190 r / min to fully mix the wastewater with the modified strong catalytic membrane and ozone.

[0067] 5) The reaction temperature was controlled at 23°C, the pH value was adjusted to 7.3, and the reaction time was 55 min.

[0068] 6) After the reaction is completed, turn off the ozone generator and stirring device, open the outlet valve, and discharge the treated wastewater out of the membrane reactor.

[0069] Example 8 The steps of preparing the PTFE modified membrane and the process and constructing the wastewater treatment system are consistent with those in Example 1, except that the specific operation steps of the wastewater treatment are different from those in Example 1.

[0070] 1) The treated wastewater is organic wastewater from a chemical plant. The main pollutants are benzene series with a concentration of 500 mg / L.

[0071] 2) Open the water inlet valve and introduce wastewater into the membrane reactor until the liquid level reaches 80% of the height of the membrane reactor.

[0072] 3) Start the ozone generator, adjust the ozone production to 100g / h, and transport the ozone to the membrane reactor through the ozone delivery pipe.

[0073] 4) Start the stirring device at a speed of 210 r / min to fully mix the wastewater with the modified strong catalytic membrane and ozone.

[0074] 5) The reaction temperature was controlled at 27°C, the pH was adjusted to 7.7, and the reaction time was 65 min.

[0075] 6) After the reaction is completed, turn off the ozone generator and stirring device, open the outlet valve, and discharge the treated wastewater out of the membrane reactor.

[0076] Comparative Example 1 The process steps for preparing the PTFE modified membrane, the steps for constructing the wastewater treatment system, and the wastewater treatment process were the same as in Example 1, except that the mass ratio of the titanium dioxide catalyst particles to the 50 μm PTFE polymer powder in the raw materials was 3:1.

[0077] Comparative Example 2 The process steps for preparing the PTFE modified membrane, the steps for constructing the wastewater treatment system, and the wastewater treatment process were the same as in Example 1, except that the mass ratio of the titanium dioxide catalyst particles to the 50 μm PTFE polymer powder in the raw materials was 17:1.

[0078] Comparative Example 3 The process steps for preparing the PTFE modified membrane and the steps for constructing the wastewater treatment system were the same as in Example 1, except that the stirring speed in the wastewater treatment process was 180 r / min, the reaction temperature was controlled at 21°C, the pH value was adjusted to 7.0, and the reaction time was 50 min.

[0079] Comparative Example 4 The process steps for preparing the PTFE modified membrane and the steps for constructing the wastewater treatment system were the same as in Example 1, except that the stirring speed in the wastewater treatment process was 220 r / min, the reaction temperature was controlled at 29°C, the pH value was adjusted to 7.9, and the reaction time was 70 min.

[0080] Comparative Example 5 The process steps for preparing the PTFE modified membrane, the steps for constructing the wastewater treatment system, and the wastewater treatment process were the same as in Example 4, except that the mass ratio of the manganese dioxide catalyst particles to the 50 μm PTFE polymer powder in the raw materials was 4:1.

[0081] Comparative Example 6 The process steps for preparing the PTFE modified membrane, the steps for constructing the wastewater treatment system, and the wastewater treatment process were the same as in Example 4, except that the mass ratio of the manganese dioxide catalyst particles to the 50 μm PTFE polymer powder in the raw materials was 24:1.

[0082] Comparative Example 7 The process steps for preparing the PTFE modified membrane and the steps for constructing the wastewater treatment system were the same as in Example 4, except that the stirring speed in the wastewater treatment process was 220 r / min, the reaction temperature was controlled at 26°C, the pH value was adjusted to 7.6, and the reaction time was 80 min.

[0083] Comparative Example 8 The process steps for preparing the PTFE modified membrane and constructing the wastewater treatment system were the same as those in Example 4, except that the stirring speed of the wastewater treatment process was 280 r / min, the reaction temperature was controlled at 39° C., the pH value was adjusted to 10, and the reaction time was 100 min.

[0084] Test results Performance tests were conducted to examine the treatment effects of the above-mentioned examples and comparative examples. The test results were as follows: The concentration of BTEX in the chemical plant wastewater after purification in Example 1 was 48.3 mg / L, with a removal rate of 90.2%. The concentration of BTEX in the chemical plant wastewater after purification in Example 2 was 50.1 mg / L, with a removal rate of 88.4%. The concentration of BTEX in the chemical plant wastewater after purification in Example 3 was 49.6 mg / L, with a removal rate of 87.9%. The concentration of dye in the printing and dyeing wastewater after purification in Example 4 was 78.9 mg / L, with a removal rate of 90.1%. The concentration of dye in the printing and dyeing wastewater after purification in Example 5 was 80.2 mg / L, with a removal rate of 89.2%. The concentration of dye in the printing and dyeing wastewater after purification in Example 6 was 79.8 mg / L, with a removal rate of 88.9%. The concentration of BTEX in the chemical plant wastewater after purification in Comparative Example 1 was 51.7 mg / L, with a removal rate of 87.2%. After purification in Comparative Example 2, the concentration of benzene series in the chemical plant wastewater was 50.3 mg / L, with a removal rate of 89.4%. After purification in Comparative Example 3, the concentration of benzene series in the chemical plant wastewater was 52.5 mg / L, with a removal rate of 88.3%. After purification in Comparative Example 4, the concentration of benzene series in the chemical plant wastewater was 53.7 mg / L, with a removal rate of 89.5%. After purification in Comparative Example 5, the concentration of dye in the printing and dyeing wastewater was 82.9 mg / L, with a removal rate of 88.1%. After purification in Comparative Example 6, the concentration of dye in the printing and dyeing wastewater was 81.2 mg / L, with a removal rate of 89.6%. After purification in Comparative Example 7, the concentration of dye in the printing and dyeing wastewater was 81.6 mg / L, with a removal rate of 86.8%. After purification in Comparative Example 8, the concentration of dye in the printing and dyeing wastewater was 82.3 mg / L, with a removal rate of 88.9%.

[0085] The measurement results are shown in Table 1: Table 1

[0086] The measurement results in Table 1 show that, with a reasonable mass ratio of metal oxide catalyst particles to PTFE polymer, the water treatment effects of Examples 1-8 are all superior to those of Comparative Examples 1 and 5. This is because there is an optimal dosage range for titanium dioxide catalyst particles, and the TiO2 dosage must be controlled within an appropriate range. When the dosage is too low, the catalyst active sites are insufficient, resulting in low organic matter degradation efficiency; when the dosage is too high, the particles agglomerate and shield the active sites, potentially hindering light transmission or increasing solution turbidity, thereby reducing catalytic efficiency. The reason for the negative effects of excessive use is that excessive TiO2 reduces the contact of effective reaction sites due to the "concentration dilution effect." Studies on dye wastewater degradation have also confirmed that when the TiO2 dosage exceeds the reasonable dosage range, the degradation rate actually decreases. The function of PTFE polymer as a catalyst carrier requires a controlled mass ratio with the metal oxide catalyst particles to balance catalyst dispersibility, carrier stability, and mass transfer efficiency.

[0087] The ratio of the metal oxide catalyst particles to the PTFE polymer of the present invention is scientific and reasonable. In addition, for Examples 1-8, the metal oxide catalyst particles of Examples 1 and 4 produce the best effect when added in an amount in the middle of the mass ratio range.

[0088] As for the comparison results of Comparative Example 1 and Example 1, when the mass ratio of titanium dioxide catalyst particles in the raw material is too low, the catalyst active sites are insufficient, resulting in low efficiency in organic matter degradation, which has a great impact on the concentration of benzene series, thereby reducing the chemical wastewater treatment effect.

[0089] As for the comparison results of Comparative Example 2 and Example 1, when the mass ratio of titanium dioxide catalyst particles in the raw material is too high, the particles agglomerate to shield the active sites and may hinder light transmission or increase solution turbidity, thereby reducing the catalytic efficiency and thus reducing the chemical wastewater treatment effect.

[0090] As for the comparison results of Comparative Example 3 and Example 1, when the stirring speed in the wastewater treatment process is too low, the reaction temperature is too low, the pH value is small, and the reaction time is too short, then the temperature reduction will lead to a decrease in the average kinetic energy of the molecules, a decrease in the effective collision frequency, and a decrease in the reaction rate. In the catalytic reaction, the low temperature leads to insufficient reaction depth, incomplete reaction, and a decrease in the yield of the target product, which has a great impact on the concentration and removal rate of benzene series, thereby reducing the effect of chemical wastewater treatment.

[0091] As for the comparison results of Comparative Example 4 and Example 1, when the reaction temperature in the wastewater treatment process is too high, the pH value is large, and the reaction time is too long, then the reaction temperature is too high, the activity of the catalyst is greatly reduced, the reaction efficiency is reduced, and the reaction time is too long, which will lead to excessive reaction of the components and excessive conversion of the intermediate products into by-products, resulting in negative effects, thereby reducing the treatment effect of chemical wastewater.

[0092] Comparing the results of Comparative Example 5 with Example 4, when the mass ratio of the manganese dioxide catalyst particles in the raw material is too low, the catalyst active sites are insufficient, resulting in low efficiency in organic matter degradation, which has a great impact on the concentration of the dye, thereby reducing the treatment effect of printing and dyeing wastewater.

[0093] For the comparison results of Comparative Example 6 and Example 4, when the mass ratio of manganese dioxide catalyst particles in the raw material is too high, the particles agglomerate to shield the active sites and may hinder light transmission or increase solution turbidity, thereby reducing the catalytic efficiency and thus reducing the treatment effect of printing and dyeing wastewater.

[0094] For the comparison results of Comparative Example 7 and Example 4, when the stirring speed in the wastewater treatment process is too low, the reaction temperature is too low, the pH value is small, and the reaction time is too short, then the temperature reduction will lead to a decrease in the average kinetic energy of the molecules, a decrease in the effective collision frequency, and a decrease in the reaction rate. In the catalytic reaction, the low temperature leads to insufficient reaction depth, incomplete reaction, and a decrease in the yield of the target product, which has a great impact on the concentration and removal rate of benzene series, thereby reducing the treatment effect of printing and dyeing wastewater.

[0095] For the comparison results of Comparative Example 8 and Example 4, when the reaction temperature in the wastewater treatment process is too high, the pH value is large, and the reaction time is too long, then the reaction temperature is too high, the activity of the catalyst is greatly reduced, the reaction efficiency is reduced, and the reaction time is too long, which will lead to excessive reaction of the components and excessive conversion of the intermediate products into by-products, resulting in negative effects, thereby reducing the treatment effect of printing and dyeing wastewater.

[0096] In summary, the PTFE-modified membrane prepared by the modification method of the present invention has the ability to treat chemical wastewater and printing and dyeing wastewater, improves the ozone gasification catalytic effect on the membrane material surface of the hollow fiber membrane module, achieves sufficient contact, mixing, and net removal of pollutants and ozone, and improves the pollutant removal rate and the quality of the wastewater treatment output product. By controlling the reaction conditions in this embodiment, the ozone catalytic oxidation reaction can be carried out under optimal conditions, further improving the treatment effect; the process flow is simple, on-site application is convenient, and the product performance is stable.

[0097] Although the present invention has been illustrated and described with specific embodiments, it will be appreciated that many other changes and modifications may be made without departing from the spirit and scope of the present invention. It is therefore intended that the appended claims include all such changes and modifications that fall within the scope of the present invention.

Claims

1. PTFE modified membrane, characterized in that, The PTFE modified membrane is obtained by adding metal oxide catalyst particles to the PTFE polymer. The weight of the metal oxide catalyst particles accounts for 5%-20% of the weight of the PTFE polymer. The diameter of the metal oxide catalyst particles is 10-100nm. The porosity of the PTFE modified membrane is 53-62%, and the pore size range is 0.1-1μm.

2. The PTFE modified membrane according to claim 1, wherein The metal oxide catalyst particles are any one of titanium dioxide catalyst particles and manganese dioxide catalyst particles; When the metal oxide catalyst particles are titanium dioxide catalyst particles, the weight of the titanium dioxide catalyst particles accounts for 5%-15% of the weight of the PTFE polymer; the diameter of the titanium dioxide catalyst particles is 10-50 nm, and the porosity of the PTFE modified membrane is 58-62%.

3. The PTFE modified membrane according to claim 2, wherein The weight of the titanium dioxide catalyst particles accounts for 10% of the weight of the PTFE polymer; the diameter of the titanium dioxide catalyst particles is 20-30 nm, and the porosity of the PTFE modified membrane is 60%.

4. The PTFE modified membrane according to claim 2, characterized in that When the metal oxide catalyst particles are manganese dioxide catalyst particles, the weight of the manganese dioxide catalyst particles accounts for 8%-20% of the weight of the PTFE polymer; the diameter of the manganese dioxide catalyst particles is 20-100 nm, and the porosity of the PTFE modified membrane is 53-57%.

5. The PTFE modified membrane according to claim 4, characterized in that The weight of the manganese dioxide catalyst particles accounts for 14% of the weight of the PTFE polymer; the diameter of the manganese dioxide catalyst particles is 30-50 nm, and the porosity of the PTFE modified membrane is 55%.

6. A method for modifying a PTFE modified membrane, for producing a PTFE modified membrane as claimed in any one of claims 1 to 5, characterized in that: The blending-phase inversion method is adopted, comprising the following steps: Mix PTFE polymer powder with a particle size of 50-100 μm with titanium dioxide or manganese dioxide catalyst particles in proportion, add organic solvent N-methylpyrrolidone or NMP, and stir at 60-80°C for 2-4 hours to form a uniform sol; The sol is processed into a membrane through an extrusion process, and the membrane is immersed in an ice-water coagulation bath. The coagulation bath solvent and water phase separate to form a porous structure. The coagulation bath temperature is controlled at 0-5°C and the coagulation time is 10-20 minutes to adjust the pore size and porosity of the membrane. The formed membrane is heat treated at 120-150°C for 1-2 hours to eliminate the stress in the membrane and improve the mechanical strength of the membrane; then it is rinsed with deionized water 3-5 times to remove the residual solvent.

7. A wastewater treatment system using the PTFE modified membrane according to any one of claims 1 to 5, characterized in that: include: A wastewater treatment device and an ozone supply device, wherein the wastewater treatment device includes a membrane reactor, and the ozone supply device is connected to the membrane reactor; a hollow fiber membrane component processed from the PTFE modified membrane and a stirring device for stirring wastewater are arranged inside the membrane reactor.

8. The wastewater treatment system according to claim 7, characterized in that: The stirring device adopts a mechanical stirrer, and the mechanical stirrer comprises a stirring shaft passing through the top of the membrane reactor and a stirring blade fixedly connected to the lower part of the stirring shaft.

9. A wastewater treatment method, applied to the wastewater treatment system according to claim 7 or 8, characterized in that: The steps include: A. Introduce wastewater until the liquid level reaches the set height; B. Adjust the ozone generation rate. When the metal oxide catalyst particles of the PTFE modified membrane are titanium dioxide catalyst particles, the ozone generation rate is 100 g / h. When the metal oxide catalyst particles of the PTFE modified membrane are manganese dioxide catalyst particles, the ozone generation rate is 150 g / h. Transport the ozone to contact and react with the PTFE modified membrane. C. Stirring the wastewater, when the metal oxide catalyst particles of the PTFE modified membrane are titanium dioxide catalyst particles, the stirring speed is 190-210 r / min, when the metal oxide catalyst particles of the PTFE modified membrane are manganese dioxide catalyst particles, the stirring speed is 240-260 r / min; fully mixing the wastewater with the PTFE modified membrane and ozone; D. After the reaction is completed, the treated wastewater is discharged.

10. The wastewater treatment method according to claim 9, characterized in that: When the metal oxide catalyst particles of the PTFE modified membrane are titanium dioxide catalyst particles, the reaction temperature of step B and step C is controlled at 23-27° C., the pH value is adjusted to 7.3-7.7, and the reaction time is 55-65 min; When the metal oxide catalyst particles of the PTFE modified membrane are manganese dioxide catalyst particles, the reaction temperature of step B and step C is controlled at 28-32° C., the pH value is adjusted to 7.8-8.2, and the reaction time is 85-95 min.

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