Integrated electrolysis ozone catalytic oxidation pressure type ceramic membrane water purification system

Abstract

The application discloses a pressure type ceramic membrane water purification system integrated with electrolysis and ozone catalytic oxidation, and belongs to the technical field of water treatment. The pressure type ceramic membrane water purification system integrated with electrolysis and ozone catalytic oxidation has high water purification efficiency, long service life of the ceramic membrane, and can effectively remove small molecule pollutants. The pressure type ceramic membrane water purification system integrated with electrolysis and ozone catalytic oxidation comprises a water inlet valve, an ozone preparation unit, an ozone mixing unit, a pressure type ceramic membrane unit, a water production valve, a backwashing pump, a chemical feeding pump, a cleaning valve, a blowdown valve and a clean water tank. The low-voltage direct-current electrolysis technology is adopted to prepare ozone, high-quality and high-concentration ozone is generated at an anode, and the by-products are oxygen and hydrogen, which are clean and pollution-free. The application adopts a catalytic pressure type ceramic membrane water purification process, has small land occupation, and greatly improves membrane flux. In addition, the system cooperates with the ozone catalytic oxidation technology, and can efficiently remove water pollution, especially organic matters in water.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to a pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation. Background Technology

[0002] With the gradual improvement of drinking water quality standards, there is an urgent need for further upgrading and transformation of conventional water treatment processes. In recent years, the application of ultrafiltration (UF) technology in drinking water treatment has gradually increased. This advanced water treatment technology has the potential to replace traditional treatment units such as coagulation, sedimentation, and sand filtration, promoting water quality improvement while also providing new possibilities for streamlining water plant processes. Ultrafiltration (UF), as a membrane separation technology, is considered a very promising drinking water production process due to its compact size, ease of automation, and high removal rates of turbidity, organic matter, Giardia lamblia, and viruses. Microfiltration and ultrafiltration membranes have larger pore sizes, higher water flux, and lower transmembrane pressure. Microfiltration membranes are used to remove suspended particles and various microorganisms, while ultrafiltration membranes, typically with pore sizes between 10-100 nm, can remove colloids, viruses, and high molecular weight components of natural organic matter. Compared to nanofiltration and reverse osmosis, ultrafiltration has lower operating costs.

[0003] Currently, organic membranes are widely used in water and wastewater treatment. However, due to their hydrophobicity, poor stability to chemicals, and high tendency to foul, their performance is affected, as is their long-term sustainability. In this context, the application of ceramic membranes in water and wastewater treatment has attracted widespread attention.

[0004] The thermal / chemical stability, low fouling tendency, and long lifespan of ceramic membranes make them highly attractive, and their application in water and wastewater treatment is rapidly increasing. Ceramic membranes can be combined with oxidation treatments, while in-situ ozonation and other oxidation methods cannot be used with organic membranes due to the potential degradation of the membrane during long-term exposure. Furthermore, ceramic membranes offer higher flux, higher pollutant removal rates, lower fouling rates, and higher cleaning efficiency, outperforming traditional organic membranes.

[0005] Depending on the source water quality and the required drinking water quality, multiple treatment processes are typically required, including pre-oxidation, coagulation, sedimentation, filtration, and disinfection. Ceramic membranes, as a new option, hold promise for replacing traditional pretreatment processes and shortening the process flow. However, after long-term operation, the membrane surface is susceptible to fouling by organic matter, microorganisms, colloids, and other substances, leading to decreased membrane flux, increased membrane resistance, reduced membrane performance and lifespan. Furthermore, they are ineffective at removing small-molecule pollutants and have high production costs. To extend the operating time of ceramic membranes, they can be combined with pretreatment processes such as oxidation and activated carbon adsorption to reduce membrane fouling and improve the removal rate of pollutants in the water. However, despite the large specific surface area and high porosity of activated carbon, a single adsorbent often struggles to meet the removal requirements of different organic compounds.

[0006] Membrane water treatment technology has shown outstanding performance in water treatment. Through the retention and adsorption of membranes, it can greatly reduce suspended pollutants in water and significantly reduce water turbidity. However, it is often accompanied by serious membrane fouling problems during the treatment process, which affects the membrane's lifespan. At the same time, it cannot effectively remove small molecule pollutants in water, and the production cost is high. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation. This ceramic membrane water purification system has high water purification efficiency, a long service life of the ceramic membrane, and can effectively remove small molecule pollutants.

[0008] An integrated electrolytic ozone catalytic oxidation pressure ceramic membrane water purification system includes an inlet valve 1, an ozone preparation unit 2, an ozone mixing unit 3, a pressure ceramic membrane unit 4, a product water valve 5, a backwash pump 6, a dosing pump 7, a cleaning valve 8, a drain valve 9, and a clean water tank 10.

[0009] The inlet valve 1 and ozone preparation unit 2 are respectively connected to the two inlets of ozone mixing unit 3; the outlet of ozone mixing unit 3 is connected to the inlet at the top of pressure ceramic membrane unit 4; the drain outlet at the bottom of pressure ceramic membrane unit 4 is connected to drain valve 9; the outlet of pressure ceramic membrane unit 4 is connected to one end of product water valve 5, and the other end of product water valve 5 is connected to the inlet of clean water tank 10.

[0010] The outlet of the clean water tank 10 is connected to the drain outlet of the product water tank and the pressure ceramic membrane unit 4 respectively; a backwash pump 6 and a cleaning valve 8 are provided on the pipeline connecting the clean water tank 10 and the drain outlet of the pressure ceramic membrane unit 4.

[0011] The pipeline connecting the clean water tank 10 and the drain port of the pressure ceramic membrane unit 4 is also connected to the chemical washing unit via the dosing pump 7.

[0012] Compared with the prior art, the present invention has the following advantages:

[0013] I. This invention uses low-voltage direct current electrolysis technology to prepare ozone, producing high-quality concentration ozone at the anode, with oxygen and hydrogen as byproducts, which is clean and pollution-free;

[0014] Second, this invention adopts a catalytic pressure ceramic membrane water purification process, which has a small footprint and significantly improved membrane flux; in addition, the system is combined with ozone catalytic oxidation technology, which can efficiently remove water pollution, especially organic matter in water.

[0015] Third, this invention uses physical cleaning with mechanical cleaning brushes, ozone water backwashing, and online chemical cleaning to clean pressure ceramic membranes, which can effectively prevent ceramic membrane clogging and extend the service life of ceramic membranes.

[0016] IV. The core of the ozone catalyst prepared by this invention is a ternary dopant of boron, copper and potassium. Boron, copper and potassium have a synergistic effect. The ternary dopant of boron, copper and potassium can change the surface chemical shape of the catalyst, generate new active sites, and generate nitrogen defects, thereby enhancing the adsorption and activation of ozone.

[0017] V. The ozone catalyst prepared by this invention has a core-shell structure, high catalytic activity, long lifespan, and excellent catalytic ozone decomposition performance.

[0018] VI. The catalytic ozone functional ceramic membrane prepared by this invention has excellent water permeability and can degrade various organic pollutants. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an integrated electrolytic ozone catalytic oxidation pressure ceramic membrane water purification system according to the present invention. In the figure, 1 is the inlet valve, 2 is the ozone preparation unit, 3 is the ozone mixing unit, 4 is the pressure ceramic membrane unit, 5 is the product water valve, 6 is the backwash pump, 7 is the dosing pump, 8 is the cleaning valve, 9 is the drain valve, and 10 is the clean water tank. Detailed Implementation

[0020] Detailed implementation method one: Please refer to Figure 1 This embodiment describes an integrated electrolytic ozone catalytic oxidation pressure ceramic membrane water purification system, including an inlet valve 1, an ozone preparation unit 2, an ozone mixing unit 3, a pressure ceramic membrane unit 4, a product water valve 5, a backwash pump 6, a dosing pump 7, a cleaning valve 8, a drain valve 9, and a clean water tank 10.

[0021] The inlet valve 1 and ozone preparation unit 2 are respectively connected to the two inlets of ozone mixing unit 3; the outlet of ozone mixing unit 3 is connected to the inlet at the top of pressure ceramic membrane unit 4; the drain outlet at the bottom of pressure ceramic membrane unit 4 is connected to drain valve 9; the outlet of pressure ceramic membrane unit 4 is connected to one end of product water valve 5, and the other end of product water valve 5 is connected to the inlet of clean water tank 10.

[0022] The outlet of the clean water tank 10 is connected to the drain outlet of the product water tank and the pressure ceramic membrane unit 4 respectively; a backwash pump 6 and a cleaning valve 8 are provided on the pipeline connecting the clean water tank 10 and the drain outlet of the pressure ceramic membrane unit 4.

[0023] The pipeline connecting the clean water tank 10 and the drain port of the pressure ceramic membrane unit 4 is also connected to the chemical washing unit via the dosing pump 7.

[0024] For a specific implementation of an integrated electrolytic ozone catalytic oxidation pressure-type ceramic membrane water purification system, please refer to [link / reference]. Figure 1 During water production, the inlet valve 1 is opened, and the ozone-filled raw water enters the pressure ceramic membrane unit 4. The ozone reacts with the organic matter adhering to the membrane surface, improving membrane surface fouling, reducing membrane fouling, and extending the membrane service life. After water production is completed, the cleaning valve 8 is opened, and the backwash pump 6 is turned on. The water filtered through the membrane is filled with ozone, and the ozone water is used to perform online backwashing on the pressure ceramic membrane to remove pollutants adhering to the inside of the ceramic membrane, thereby realizing online ozone cleaning of the pressure ceramic membrane unit 4 both outside and inside the membrane.

[0025] In this specific embodiment, the backwashing time can be set according to the membrane fouling situation and the raw water quality. For example, if the raw water quality is poor and the membrane fouling is not severe, the backwashing cycle can be set to 1-3 days, and the backwashing time can be set to 5-60 seconds. If the raw water quality is poor and the membrane fouling is severe, the backwashing cycle can be set to 2-4 hours, and the backwashing time can be set to 1-5 minutes.

[0026] As a specific embodiment of the integrated electrolytic ozone catalytic oxidation pressure-type ceramic membrane water purification system provided by the present invention, please refer to [link / reference]. Figure 1 During the chemical washing process, after the cleaning valve 8 is opened, the dosing pump 7 is opened simultaneously when the backwash pump 6 is turned on, so as to realize the chemical washing process of the pressure ceramic membrane unit 4.

[0027] In this specific embodiment, depending on the type of pollutants in the water, agents such as sodium hypochlorite, sodium hydroxide, citric acid, hydrogen peroxide, and hydrochloric acid can be selected to clean the ceramic membrane. The specific cleaning mode is determined according to the actual fouling situation of the ceramic membrane.

[0028] In this specific embodiment, a mechanical cleaning brush can also be used to physically clean the inside of the pressure ceramic membrane unit 4 to prevent the ceramic membrane from becoming clogged and extend its service life.

[0029] In this specific embodiment, the external air washing time can be set according to the actual raw water quality and membrane fouling performance.

[0030] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the ozone preparation unit 2 uses low-pressure water electrolysis technology to prepare high-concentration ozone, with an ozone concentration greater than 20%. Other steps are the same as in Specific Implementation Method One.

[0031] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the water electrolyzed in the ozone preparation unit 2 contains dilute sulfuric acid or hydrochloric acid to increase conductivity; aluminum is used as the cathode, and Pt, SbO2, glassy carbon, or diamond is used as the anode; a perfluorosulfonic acid ion exchange membrane is employed. Other steps are the same as in Specific Implementation Method 1 or 2.

[0032] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the ozone generated by the electrolysis in the ozone preparation unit 2 is added using micro-nano bubble technology and enters the ozone mixing unit 3, allowing the water to be treated to fully mix and react with the ozone. Other steps are the same as in Specific Implementation Methods One to Three.

[0033] Specific Implementation Method Five: The difference between this implementation method and Specific Implementation Methods One to Four is that the pressure-type ceramic membrane unit 4 uses a catalytic ceramic membrane. The other steps are the same as in Specific Implementation Methods One to Four.

[0034] Specific Implementation Method Six: The difference between this implementation method and Specific Implementation Methods One to Five is that the catalytic ceramic membrane is a functional ceramic membrane for catalytic ozone removal, and the preparation method is specifically completed according to the following steps:

[0035] I. Preparation of ozone catalysts:

[0036] ① Disperse the nitrogen source, boron source, copper source and potassium source in the solvent, then heat and stir for a period of time; then evaporate the solvent, grind, and obtain the precursor powder;

[0037] ② Place the precursor powder in a muffle furnace, heat it to the calcination temperature, and calcine it at the calcination temperature for a period of time to obtain boron-copper-potassium ternary doped carbon nitride.

[0038] ③ Aluminum sol is sprayed onto the outer surface of boron-copper-potassium ternary doped carbon nitride, and then dried and calcined to obtain a core-shell catalyst;

[0039] ④ Dissolve lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in water to obtain a metal salt solution;

[0040] ⑤ Immerse the core-shell catalyst in a metal salt solution, then add a complexing agent solution, stir for a period of time, take it out and dry it, then calcine it at 150℃~250℃ for 1h~2h, and finally calcine it at 900℃~950℃ for 2h~3h to obtain an ozone catalyst.

[0041] II. Preparation of functional ceramic membranes for catalytic ozone formation:

[0042] ① Add ceramic membrane aggregate, sintering aid, pore-forming agent and binder into a ball mill jar and ball mill to mix them evenly. Then add ozone catalyst and continue ball milling to mix them evenly to obtain a mixed powder. Add water to the mixed powder and blend to obtain ceramic membrane blend material.

[0043] ② The ceramic membrane blend is allowed to stand and age, and then kneaded in a vacuum kneading machine to obtain a mixed clay material. The mixed clay material is extruded to form a ceramic membrane preform. After drying the preform in an oven, it is calcined using a gradient temperature program to obtain a catalytic ozone functional ceramic membrane. Other steps are the same as in specific implementation methods one to five.

[0044] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in the following ways: the nitrogen source in step 1① is urea or melamine; the boron source in step 1① is sodium metaborate, sodium tetraborate, or boric acid; the copper source in step 1① is copper nitrate, copper sulfate, or copper acetate; the potassium source in step 1① is potassium chloride, potassium carbonate, or potassium sulfate; the solvent in step 1① is water or anhydrous ethanol; the heating and stirring temperature in step 1① is 60℃~90℃, and the heating and stirring time is 5h~7h; the molar ratio of the nitrogen source, boron source, copper source, and potassium source in step 1① is (300~500):(10~30):(1~10):(1~10). Other steps are the same as in Specific Implementation Methods One to Six.

[0045] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in the following ways: the heating rate in step 1② is 5℃ / min to 10℃ / min; the calcination temperature is 500℃ to 600℃, and the calcination time is 3h to 5h; the solid content of the aluminum sol in step 1③ is 20%; the drying temperature in step 1③ is 100℃ to 110℃, and the drying time is 2h to 5h; the roasting temperature in step 1③ is 600℃ to 700℃, and the roasting time is 5h to 7h.

[0046] In step 1③, the mass fraction of the outer shell in the core-shell catalyst is 5% to 10%. The other steps are the same as in specific embodiments one to seven.

[0047] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in the following ways: the molar ratio of lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in step one (④) is (8-10):(2-4):(1-3):(1-3); the complexing agent solution in step one (⑤) is a citric acid solution with a concentration of 2 mol / L to 4 mol / L; the volume ratio of the metal salt solution to the complexing agent solution in step one (⑤) is 1:1; and the stirring time in step one (⑤) is 2-4 hours. Other steps are the same as in Specific Implementation Methods One to Eight.

[0048] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods One to Nine in that: In step two①, one or more of the following are selected: alumina, zirconium oxide, titanium dioxide, and silicon carbide; the sintering aid in step two① is one or more of the following: clay, kaolin, potassium feldspar, sodium feldspar, calcium carbonate, and magnesium carbonate; the pore-forming agent in step two① is one or more of the following: dextrin, soluble starch, glucose, and sodium chloride; the binder in step two① is polyvinyl alcohol, methylcellulose, or polyacrylamide; and the mass ratio of the ceramic membrane aggregate, sintering aid, pore-forming agent, binder, and water in step two① is (8...). The mass ratio of ozone catalyst to ceramic membrane aggregate in step 2① is (10~15):(80~90); the calcination in step 2② is as follows: first, the temperature is raised to 600℃~800℃ at a heating rate of 5℃ / min~10℃ / min, and sintered at 600℃~800℃ for 3h~6h; then, the temperature is raised to 1200℃~1500℃ at a heating rate of 5℃ / min~10℃ / min, and sintered at 1200℃~1500℃ for 8h~12h to obtain the catalytic ozone functional ceramic membrane. Other steps are the same as in specific embodiments one to nine.

[0049] The beneficial effects of the present invention are verified using the following embodiments:

[0050] Example 1: As Figure 1 As shown, this embodiment is an integrated electrolytic ozone catalytic oxidation pressure ceramic membrane water purification system, including an inlet valve 1, an ozone preparation unit 2, an ozone mixing unit 3, a pressure ceramic membrane unit 4, a product water valve 5, a backwash pump 6, a dosing pump 7, a cleaning valve 8, a drain valve 9, and a clean water tank 10.

[0051] The inlet valve 1 and ozone preparation unit 2 are respectively connected to the two inlets of ozone mixing unit 3; the outlet of ozone mixing unit 3 is connected to the inlet at the top of pressure ceramic membrane unit 4; the drain outlet at the bottom of pressure ceramic membrane unit 4 is connected to drain valve 9; the outlet of pressure ceramic membrane unit 4 is connected to one end of product water valve 5, and the other end of product water valve 5 is connected to the inlet of clean water tank 10.

[0052] The outlet of the clean water tank 10 is connected to the drain outlet of the product water tank and the pressure ceramic membrane unit 4 respectively; a backwash pump 6 and a cleaning valve 8 are provided on the pipeline connecting the clean water tank 10 and the drain outlet of the pressure ceramic membrane unit 4.

[0053] The pipeline connecting the clean water tank 10 and the drain port of the pressure ceramic membrane unit 4 is also connected to the chemical washing unit via the dosing pump 7.

[0054] In ozone preparation unit 2, ozone is prepared using low-pressure water electrolysis technology with an ozone concentration greater than 20%. The high-concentration ozone generated is injected into the inlet water using micro-nano bubble technology for mixing. The inlet water with fully mixed ozone is filtered by a pressure ceramic membrane unit to complete the water purification process.

[0055] In this embodiment, high-concentration ozone is generated using ozone preparation unit 2. Inlet valve 1 is opened, and ozone is introduced into ozone mixing unit 3 using micro-nano bubble technology for thorough mixing. The water flows through pressure-type ceramic membrane unit 4 for membrane filtration. The ozone reacts with the ozone catalyst on the membrane to produce ozone catalytic oxidation, removing organic matter and other pollutants from the water. After membrane filtration, the turbidity of the effluent is significantly reduced, and the water quality is improved. Product water valve 5 is opened to complete the water production process. Drain valve 9 is opened to complete the ozone water rinsing and drainage process.

[0056] In this embodiment, the ozone concentration generated by the ozone preparation unit 2 is greater than 20%; the electrolyzed water contains dilute sulfuric acid to increase conductivity; aluminum is used as the cathode and Pt is used as the anode.

[0057] In this embodiment, the ozone preparation unit 2 uses a perfluorosulfonic acid ion exchange membrane, which has stable electrochemical properties, excellent mechanical properties, high conductivity, good selective permeability, and no selective separation or pressure drop phenomenon.

[0058] In this embodiment, the ozone generated by the electrolysis of the ozone preparation unit 2 is added using micro-nano bubble technology and enters the ozone mixing unit 3, so that water and ozone are fully mixed and reacted.

[0059] In this embodiment, the pressure-type ceramic membrane water purification system uses a catalytic ceramic membrane, which can achieve efficient purification of water bodies with high organic matter content and improve the organic matter removal efficiency.

[0060] The catalytic ceramic membrane described in this embodiment is a functional ceramic membrane for catalytic ozone removal, and its preparation method is specifically carried out according to the following steps:

[0061] I. Preparation of ozone catalysts:

[0062] ① Disperse urea, sodium metaborate, copper nitrate and potassium chloride in water, then heat and stir at 70°C for 6 hours; then evaporate the solvent, grind and obtain precursor powder;

[0063] The molar ratio of urea, sodium metaborate, copper nitrate and potassium chloride mentioned in step 1① is 300:15:5:3;

[0064] ② Place the precursor powder in a muffle furnace, heat it to the calcination temperature, and calcine it at the calcination temperature for a period of time to obtain boron-copper-potassium ternary doped carbon nitride.

[0065] The heating rate described in step 1② is 10℃ / min; the calcination temperature is 550℃, and the calcination time is 4h;

[0066] ③ Aluminum sol is sprayed onto the outer surface of boron-copper-potassium ternary doped carbon nitride, and then dried and calcined to obtain a core-shell catalyst;

[0067] The solid content of the aluminum sol mentioned in step 1③ is 20%;

[0068] The drying temperature in step 1③ is 100℃, and the drying time is 3 hours;

[0069] The roasting temperature in step 1③ is 650℃, and the roasting time is 6 hours;

[0070] The mass fraction of the outer shell in the core-shell catalyst described in step 1③ is 5%;

[0071] ④ Dissolve lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in water to obtain a metal salt solution;

[0072] The molar ratio of lanthanum nitrate, cerium nitrate, cadmium nitrate and cuprous chloride mentioned in step 1④ is 8:3:2:1;

[0073] ⑤ Immerse the core-shell catalyst in a metal salt solution, then add a complexing agent solution, stir for 2 hours, remove and dry, then calcine at 250℃ for 2 hours, and finally calcine at 900℃ for 2 hours to obtain an ozone catalyst.

[0074] The complexing agent solution mentioned in step 1⑤ is a citric acid solution with a concentration of 3 mol / L;

[0075] The volume ratio of the metal salt solution to the complexing agent solution mentioned in step 1⑤ is 1:1;

[0076] II. Preparation of functional ceramic membranes for catalytic ozone formation:

[0077] ① Add ceramic membrane aggregate, sintering aid, pore-forming agent and binder into a ball mill jar and ball mill to mix them evenly. Then add ozone catalyst and continue ball milling to mix them evenly to obtain a mixed powder. Add water to the mixed powder and blend to obtain ceramic membrane blend material.

[0078] The aluminum oxide mentioned in step 2①;

[0079] The sintering aid mentioned in step 2① is a mixture of clay and kaolin, wherein the mass ratio of clay to kaolin is 1:1;

[0080] The pore-forming agent mentioned in step 2① is a mixture of dextrin and sodium chloride, wherein the mass ratio of dextrin to sodium chloride is 1:1;

[0081] The adhesive mentioned in step 2① is polyvinyl alcohol;

[0082] The mass ratio of ceramic membrane aggregate, sintering aid, pore-forming agent, binder and water mentioned in step 2① is 85:15:15:10:20;

[0083] The mass ratio of ozone catalyst to ceramic membrane aggregate mentioned in step 2① is 10:85;

[0084] ② The ceramic membrane blend is left to stand and age, and then processed by a vacuum plow to obtain a mixed plow; the mixed plow is extruded to form a ceramic membrane green body, which is then dried in an oven and calcined using a gradient heating program to obtain a catalytic ozone functional ceramic membrane.

[0085] The calcination described in step 2② is as follows: first, the temperature is raised to 700℃ at a heating rate of 5℃ / min, and sintered at 700℃ for 5 hours; then, the temperature is raised to 1300℃ at a heating rate of 5℃ / min, and sintered at 1300℃ for 10 hours to obtain a functional ceramic membrane for catalytic ozone generation.

[0086] Tests showed that the pure water flux can reach 3215 Lm. -2 h -1 bar -1 The turbidity removal rate reached 100%, and at an ozone concentration of 2 mg / L, the removal rate of dissolved organic carbon (DOC) was 91.7%, the total organic carbon removal rate was 85.6%, the catalytic ozone decomposition rate was 99.8%, the flux recovery rate was 98.5%, and no heavy metal leaching was detected after soaking in pure water for 30 days (1 mg / L). 2 Membrane / 10L water, flat sheet products are calculated based on the area of ​​one side, and tubular products are calculated based on the area of ​​the outer wall of the tube.

[0087] Example 2: The difference between this example and Example 1 is that the molar ratio of urea, sodium metaborate, copper nitrate, and potassium chloride in step 1① is 400:20:3:5; and the molar ratio of lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in step 1④ is 10:2:1:3. All other steps and parameters are the same as in Example 1.

[0088] Comparative Example 1: The difference between this example and Example 1 is that the preparation of boron-copper-potassium ternary doped carbon nitride is omitted. That is, the method for preparing the ozone catalyst in step one is as follows:

[0089] ① The aluminum sol is dried and calcined to obtain the catalyst;

[0090] The solid content of the aluminum sol mentioned in step 1① is 20%;

[0091] The drying temperature in step 1① is 100℃, and the drying time is 3 hours;

[0092] The roasting temperature in step 1① is 650℃, and the roasting time is 6 hours;

[0093] ② Dissolve lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in water to obtain a metal salt solution;

[0094] The molar ratio of lanthanum nitrate, cerium nitrate, cadmium nitrate and cuprous chloride mentioned in step 1② is 8:3:2:1;

[0095] ③ The catalyst is immersed in a metal salt solution, then a complexing agent solution is added, and the mixture is stirred for 2 hours. After being removed and dried, it is calcined at 250°C for 2 hours, and finally calcined at 900°C for 2 hours to obtain an ozone catalyst.

[0096] The complexing agent solution mentioned in step 1③ is a citric acid solution with a concentration of 3 mol / L;

[0097] The volume ratio of the metal salt solution to the complexing agent solution in step 1, ③ is 1:1. All other steps and parameters are the same as in Example 1.

[0098] Comparative Example 2: No ozone catalyst was prepared; the ozone catalyst mentioned in step two was a commercially available ozone catalyst. All other steps and parameters were the same as in Example 1.

[0099] Comparative Example 3: No ozone catalyst added. All other steps and parameters were the same as in Example 1.

[0100] The performance of the functional ceramic membranes for catalytic ozone preparation in each embodiment and comparative example is listed in Table 1;

[0101] Table 1

[0102]

[0103] As shown in Table 1, the ceramic membranes prepared in each embodiment have excellent water permeability, high catalytic ozone decomposition rate, and significantly improved catalytic efficiency compared with the comparative example. They can effectively alleviate membrane fouling and extend the service life of the membrane.

[0104] In summary, this invention employs low-voltage DC electrolysis technology to generate ozone, resulting in a clean and pollution-free process. By combining ozone oxidation technology with pressure-type ceramic membrane filtration technology, ozone reacts with the catalyst on the membrane surface to catalytically oxidize and remove pollutants from the water. Simultaneously, the ozone reacts with pollutants on the membrane surface, improving membrane fouling, inhibiting ceramic membrane clogging, and extending the lifespan of the ceramic membrane. Furthermore, this invention integrates physical cleaning with a mechanical cleaning brush, ozone water cleaning, and online chemical cleaning to clean the pressure-type ceramic membrane, effectively preventing clogging and extending its lifespan. This water purification system is a technology capable of efficiently removing various pollutants from water, including suspended solids, organic matter, bacteria, pesticides, and viruses, while simultaneously ensuring the long-term stable operation of the ceramic membrane.

Claims

1. A pressure-type ceramic membrane water purification system integrating electrolytic ozone catalytic oxidation, characterized in that... The integrated electrolytic ozone catalytic oxidation pressure ceramic membrane water purification system includes an inlet valve (1), an ozone preparation unit (2), an ozone mixing unit (3), a pressure ceramic membrane unit (4), a product water valve (5), a backwash pump (6), a dosing pump (7), a cleaning valve (8), a drain valve (9), and a clean water tank (10). The inlet valve (1) and ozone preparation unit (2) are respectively connected to the two inlets of ozone mixing unit (3); the outlet of ozone mixing unit (3) is connected to the inlet at the top of pressure ceramic membrane unit (4); the drain outlet at the bottom of pressure ceramic membrane unit (4) is connected to drain valve (9); the outlet of pressure ceramic membrane unit (4) is connected to one end of product water valve (5), and the other end of product water valve (5) is connected to the inlet of clear water tank (10); The outlet of the clean water tank (10) is connected to the drain outlet of the product water tank and the pressure ceramic membrane unit (4) respectively; a backwash pump (6) and a cleaning valve (8) are provided on the pipeline connecting the clean water tank (10) and the drain outlet of the pressure ceramic membrane unit (4). The pipeline connecting the clean water tank (10) and the drain of the pressure ceramic membrane unit (4) is also connected to the chemical washing unit via the dosing pump (7); The pressure-type ceramic membrane unit (4) uses a catalytic ceramic membrane; The catalytic ceramic membrane is a functional ceramic membrane for catalytic ozone generation, and its preparation method is specifically carried out according to the following steps: I. Preparation of ozone catalysts: ① Disperse the nitrogen source, boron source, copper source and potassium source in the solvent, then heat and stir for a period of time; then evaporate the solvent, grind, and obtain the precursor powder; The nitrogen source mentioned in step 1① is urea or melamine; The boron source mentioned in step 1① is sodium metaborate, sodium tetraborate, or boric acid; The copper source mentioned in step 1① is copper nitrate, copper sulfate, or copper acetate; The potassium source mentioned in step 1① is potassium chloride, potassium carbonate, or potassium sulfate; ② Place the precursor powder in a muffle furnace, heat it to the calcination temperature, and calcine it at the calcination temperature for a period of time to obtain boron-copper-potassium ternary doped carbon nitride. ③ Aluminum sol is sprayed onto the outer surface of boron-copper-potassium ternary doped carbon nitride, and then dried and calcined to obtain a core-shell catalyst; ④ Dissolve lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in water to obtain a metal salt solution; ⑤ Immerse the core-shell catalyst in a metal salt solution, then add a complexing agent solution, stir for a period of time, take it out and dry it, then calcine it at 150℃~250℃ for 1h~2h, and finally calcine it at 900℃~950℃ for 2h~3h to obtain an ozone catalyst. II. Preparation of functional ceramic membranes for catalytic ozone formation: ① Add ceramic membrane aggregate, sintering aid, pore-forming agent and binder into a ball mill jar and ball mill to mix them evenly. Then add ozone catalyst and continue ball milling to mix them evenly to obtain a mixed powder. Add water to the mixed powder and blend to obtain ceramic membrane blend material. The ceramic membrane aggregate mentioned in step 2① is one or a mixture of several of alumina, zirconium oxide, titanium dioxide, and silicon carbide; The sintering aid mentioned in step 2① is one or more of clay, kaolin, potassium feldspar, sodium feldspar, calcium carbonate, and magnesium carbonate; The pore-forming agent mentioned in step 2① is one or more of dextrin, soluble starch, glucose, and sodium chloride; the binder mentioned in step 2① is polyvinyl alcohol, methylcellulose, or polyacrylamide. ② The ceramic membrane blend is left to stand and aged, and then processed by a vacuum plow to obtain a mixed plow material. The mixed plow material is extruded to form a ceramic membrane green body. After drying the green body in an oven, it is calcined using a gradient heating program to obtain a catalytic ozone functional ceramic membrane.

2. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation according to claim 1, characterized in that... The ozone preparation unit (2) uses low-pressure water electrolysis technology to prepare high-concentration ozone with an ozone concentration greater than 20%.

3. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation as described in claim 1, characterized in that... The ozone preparation unit (2) electrolyzes water containing dilute sulfuric acid or hydrochloric acid to increase conductivity; aluminum is used as the cathode, and Pt, SbO2, glassy carbon or diamond is used as the anode; a perfluorosulfonic acid ion exchange membrane is used.

4. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation according to claim 1, characterized in that... The ozone generated by the electrolysis of the ozone preparation unit (2) is added using micro-nano bubble technology and enters the ozone mixing unit (3) to fully mix and react with the water to be treated.

5. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation according to claim 1, characterized in that... The solvent mentioned in step 1① is water or anhydrous ethanol; the heating and stirring temperature mentioned in step 1① is 60℃~90℃, and the heating and stirring time is 5h~7h; the molar ratio of nitrogen source, boron source, copper source and potassium source mentioned in step 1① is (300~500):(10~30):(1~10):(1~10).

6. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation according to claim 1, characterized in that... The heating rate in step 1② is 5℃ / min~10℃ / min; the calcination temperature is 500℃~600℃, and the calcination time is 3h~5h; the solid content of the aluminum sol in step 1③ is 20%; the drying temperature in step 1③ is 100℃~110℃, and the drying time is 2h~5h; the roasting temperature in step 1③ is 600℃~700℃, and the roasting time is 5h~7h; the mass fraction of the outer shell in the core-shell catalyst in step 1③ is 5%~10%.

7. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation according to claim 1, characterized in that... The molar ratio of lanthanum nitrate, cerium nitrate, cadmium nitrate, and cuprous chloride in step 1, ④ is (8~10):(2~4):(1~3):(1~3); the complexing agent solution in step 1, ⑤ is a citric acid solution with a concentration of 2 mol / L~4 mol / L; the volume ratio of the metal salt solution to the complexing agent solution in step 1, ⑤ is 1:1; and the stirring time in step 1, ⑤ is 2 h~4 h.

8. The pressure-type ceramic membrane water purification system with integrated electrolytic ozone catalytic oxidation according to claim 1, characterized in that... The mass ratio of ceramic membrane aggregate, sintering aid, pore-forming agent, binder and water in step 2① is (80~90):(10~15):(10~15):10:(15~25); the mass ratio of ozone catalyst to ceramic membrane aggregate in step 2① is (10~15):(80~90); the calcination in step 2② is as follows: first, the temperature is raised to 600℃~800℃ at a heating rate of 5℃ / min~10℃ / min, and sintered at 600℃~800℃ for 3h~6h, then the temperature is raised to 1200℃~1500℃ at a heating rate of 5℃ / min~10℃ / min, and sintered at 1200℃~1500℃ for 8h~12h to obtain the catalytic ozone functional ceramic membrane.

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