A method for treating wastewater by high-efficiency ozone oxidation based on ceramic membrane

Abstract

The application discloses a kind of based on ceramic membrane high-efficiency ozone oxidation wastewater treatment method, comprising the following steps: S1, in reactor, where the reactor includes reactor body and modified ceramic membrane, the modified ceramic membrane is placed in reactor body as aeration head, for with external ozone generator connection, to carry out aeration to ozone micron gas bubble;The modified ceramic membrane includes flat ceramic membrane and MnCoSi catalyst, the MnCoSi catalyst is fixedly loaded on the surface and membrane hole of the flat ceramic membrane, and in the MnCoSi catalyst, the molar ratio of Mn and Co is in the range of (1~3): (1~2);S2, ozone is aerated to micron gas bubble by the modified ceramic membrane, and the new pollutants in the wastewater are removed.The present application has the advantages of high ozone utilization rate, good catalyst stability, low energy consumption, etc., and can be widely used in wastewater advanced treatment.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and specifically to a method for treating wastewater using high-efficiency ozone oxidation based on ceramic membranes. Background Technology

[0002] Ozone oxidation technology, with its strong oxidizing properties (ozone molecule oxidation potential 2.07 V, hydroxyl radical ·OH up to 2.8 V) and cost advantages, has become an effective means of degrading toxic and harmful pollutants. Its mechanisms include: direct oxidation, where ozone selectively attacks electron-rich groups, efficiently removing easily degradable pollutants; and indirect oxidation, where ozone decomposes to produce ·OH, indiscriminately degrading various organic compounds. However, this technology still has some problems: low mass transfer efficiency, the millimeter-sized bubbles generated by traditional aeration result in a small gas-liquid contact area and low ozone solubility (utilization rate <30%); low oxidation activity, with selective reactions; insufficient oxidation efficiency for recalcitrant pollutants; and the need for homogeneous catalysts (such as Fe). 2+ Ozone is difficult to recover, and heterogeneous catalysts (such as MnO2) cannot simultaneously address issues like low ozone mass transfer efficiency. Therefore, improving both ozone mass transfer efficiency and ozone oxidation activity during wastewater treatment is crucial for enhancing ozone oxidation.

[0003] It should be noted that the information disclosed in the background section above is only for understanding the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] To address the problems of low mass transfer efficiency, low oxidation activity, and low degradation efficiency of difficult-to-treat new pollutants in ozone oxidation, this invention provides a high-efficiency ozone oxidation wastewater treatment method based on ceramic membranes.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for treating wastewater using high-efficiency ozone oxidation based on ceramic membranes includes the following steps:

[0007] S1. Wastewater is added to the reactor, wherein the reactor includes a reactor body and a modified ceramic membrane. The modified ceramic membrane is placed in the reactor body as an aeration head for connection with an external ozone generator to aerate ozone and generate micron-sized bubbles. The modified ceramic membrane includes a flat ceramic membrane and a MnCoSi catalyst. The MnCoSi catalyst is fixedly loaded on the surface of the flat ceramic membrane and in the membrane pores. In the MnCoSi catalyst, the molar ratio of Mn to Co is in the range of (1~3):(1~2).

[0008] S2. Ozone is aerated through the modified ceramic membrane to generate micron-sized bubbles, which remove new pollutants from the wastewater.

[0009] This invention offers the following advantages: By immobilizing a MnCoSi catalyst on a flat ceramic membrane, this invention integrates catalyst loading and ozone microbubble generation into a single flat ceramic membrane, constructing a microbubble ozone mass transfer system. This forms a synergistic mechanism of "microbubble mass transfer enhancement - catalyst interface enhancement," significantly improving ozone mass transfer efficiency, ozone oxidation activity, ozone utilization rate, and degradation efficiency of new pollutants, making it particularly suitable for the deep treatment of new pollutants. More specifically, this invention has the following advantages:

[0010] 1. The efficiency of pollutant removal is significantly improved.

[0011] Highly efficient mineralization of degraded organic matter: The removal rate of ozone-repellent pollutants such as DEET (N,N-diethyl-3-methylbenzamide) exceeds 99%.

[0012] 2. A breakthrough improvement in ozone utilization efficiency.

[0013] 3. Enhanced catalytic activity: The MnCoSi catalyst first generates ·O2 through the redox cycle of surface metal sites. - This leads to a chain reaction that is initiated through gas-phase or surface reactions, generating highly reactive free radical species such as ·OH. Therefore, MnCoSi catalysts can promote ozone chain reactions and increase the ·OH yield by about 3 times.

[0014] 4. Reduced energy consumption: Micron bubbles can be generated simply by physical compression, without the need for high pressure and a high proportion of gas-liquid circulating water.

[0015] 5. Possesses catalyst stability and environmental friendliness, with no secondary pollution: low metal leaching, avoiding Fe... 2+ Sludge problems with homogeneous catalysts.

[0016] This invention achieves a leap in the efficiency of ozone oxidation technology through triple innovation in materials, mass transfer, and process, combining environmental and economic benefits, and is suitable for the deep treatment of industrial wastewater, municipal reclaimed water, and other scenarios. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the reactor for the high-efficiency ozone oxidation wastewater treatment method based on ceramic membrane in an embodiment of the present invention.

[0018] Figure 2 This is a graph showing the ratio of the concentration Ct of the new pollutant (DEET) at sampling to the initial concentration C0 during the ozone oxidation wastewater treatment process, compared with a comparative example, when using the modified ceramic membrane in each embodiment of the present invention.

[0019] Figure 3This graph shows the change in liquid ozone concentration with aeration time during the mass transfer process of ozone microbubbles and millimeter bubbles under different pH conditions.

[0020] Figure 4 This is a graph showing the change of liquid-phase ozone equilibrium concentration with pH during the mass transfer process of ozone micron and millimeter bubbles under different pH conditions.

[0021] Figure 5 This is a comparison of the apparent reaction rates of ozone micron-bubble aeration and millimeter-bubble aeration under different pH conditions. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0023] This invention provides a method for treating wastewater using high-efficiency ozone oxidation based on ceramic membranes, comprising the following steps:

[0024] S1. Wastewater is added to the reactor, wherein the reactor includes a reactor body and a modified ceramic membrane. The modified ceramic membrane is placed in the reactor body as an aeration head for connection with an external ozone generator to aerate ozone and generate micron-sized bubbles. The modified ceramic membrane includes a flat ceramic membrane and a MnCoSi catalyst. The MnCoSi catalyst (MnCoSi catalyst is a Mn-enhanced cobalt silicate bimetallic material formed by introducing manganese (Mn) into cobalt-based silicate material (CoSi)) is fixedly loaded on the surface of the flat ceramic membrane and inside the membrane pores (mainly fixedly loaded on the surface of the flat ceramic membrane, and some catalyst particles can adhere to the inner wall of the membrane pores without causing blockage). In the MnCoSi catalyst, the molar ratio of Mn to Co is in the range of (1~3):(1~2).

[0025] S2. Ozone is aerated through the modified ceramic membrane to generate micron-sized bubbles, which remove new pollutants from the wastewater.

[0026] In some embodiments, the material of the flat ceramic membrane is α-Al2O3, and the pore size of the membrane is 0.1-0.9 μm.

[0027] In some embodiments, the molar ratio of Mn to Co in the MnCoSi catalyst is one of 1:1, 2:1, 3:1, or 1:2.

[0028] In some embodiments, the preparation of the modified ceramic membrane includes the following steps:

[0029] (1) 1.2-3.2 mmol of CoCl2 and 1.6-3.6 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28 wt% ammonia water to obtain a suspension;

[0030] (2) Add 0.28 g of nano-silica to the suspension obtained in step (1) and stir at room temperature for a predetermined time;

[0031] (3) Add 16 mL of ethanol to the mixed solution in step (2) and continue stirring for a predetermined time;

[0032] (4) Transfer the mixed solution from step (3) to a reaction vessel for hydrothermal reaction;

[0033] (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, while retaining the wet nanospheres to obtain the MnCoSi catalyst;

[0034] (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension.

[0035] (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% amino coupling agent;

[0036] (8) The flat ceramic membrane obtained in step (7) is refluxed at the reflux temperature of ethanol for a predetermined time to graft amino groups onto the surface of the flat ceramic membrane;

[0037] (9) The flat ceramic membrane obtained in step (8) is rinsed with ethanol to remove the physically adsorbed amino coupling agent;

[0038] (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion suspension obtained in step (6) and place it in a vacuum impregnation device, apply a predetermined vacuum pressure and process for a predetermined time.

[0039] (11) The pores of the flat ceramic membrane obtained in step (10) are purged with an inert atmosphere;

[0040] (12) Dry the flat ceramic film obtained in step (11) under vacuum;

[0041] (13) The flat ceramic membrane obtained in step (12) is annealed at 250-300°C in an inert gas atmosphere for 1-2 hours to fix the MnCoSi catalyst on the flat ceramic membrane to obtain the modified ceramic membrane.

[0042] In some implementations, the predetermined time in steps (2) and (3) is 30 minutes each.

[0043] In some implementations, the hydrothermal reaction in step (4) is carried out at a temperature of 180°C for 24 hours.

[0044] In some embodiments, the amino coupling agent in step (7) is 3-aminopropyltriethoxysilane.

[0045] In some implementations, the reflux temperature in step (8) is 80°C and the time is 2 hours.

[0046] In some implementations, the vacuum pressure in step (10) is -0.3 MPa and the processing time is 2 hours.

[0047] In some embodiments, in step (12), the product is dried in a vacuum drying oven at 60°C for 12 h.

[0048] In some implementations, in step (13), the furnace is annealed at 250°C for 1 hour in a tube furnace.

[0049] In some embodiments, the method for preparing modified ceramic membranes includes the following steps:

[0050] (1) 1.2-3.2 mmol of CoCl2 and 1.6-3.6 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28% ammonia water to obtain a suspension;

[0051] (2) Add 0.28 g of nano silica to the suspension obtained in step (1) and stir at room temperature for 30 minutes;

[0052] (3) Add 16 mL of ethanol to the mixture obtained in step (2) and continue stirring for 30 minutes;

[0053] (4) The mixed solution obtained in step (3) is transferred to a 50 mL polytetrafluoroethylene high-pressure reactor and heated at 180°C for 24 hours for hydrothermal reaction;

[0054] (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, while retaining the wet nanospheres to obtain the MnCoSi catalyst;

[0055] (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension.

[0056] (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% 3-aminopropyltriethoxysilane (APTES);

[0057] (8) The flat ceramic membrane obtained in step (7) is refluxed at 80°C for 2 h to graft amino groups onto the surface of the flat ceramic membrane;

[0058] (9) The flat ceramic membrane obtained in step (8) is rinsed three times with ethanol to remove the physically adsorbed 3-aminopropyltriethoxysilane (APTES).

[0059] (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion suspension obtained in step (6) and place it in a vacuum impregnation device, applying a vacuum pressure of -0.3 MPa for 2 h;

[0060] (11) The flat ceramic membrane obtained in step (10) is purged with nitrogen to remove unfixed or weakly bonded catalyst particles.

[0061] (12) Place the flat ceramic membrane obtained in step (11) in a vacuum drying oven at 60°C and dry for 12 h;

[0062] (13) Place the flat ceramic membrane obtained in step (12) in a tube furnace and anneal it for 1-2 hours in an inert gas atmosphere (such as nitrogen atmosphere) at 250-300℃ (heating rate 2℃ / min). Through annealing, the coupling agent (APTES) and the MnCoSi catalyst are combined, thereby fixing the MnCoSi catalyst on the flat ceramic membrane.

[0063] The MnCoSi catalyst was prepared by the above method. It is a Mn-enhanced cobalt silicate bimetallic material formed by introducing manganese (Mn) into cobalt silicate material (CoSi). The introduction of manganese (Mn) increases the oxygen vacancies in the material, thereby enhancing the catalytic performance.

[0064] In some implementations, the ozone intake flow rate is 100 ml / min.

[0065] In some implementations, the ozone inlet pressure is 0.16 MPa.

[0066] In some implementations, the ozone intake concentration is 15 mg / L.

[0067] In some embodiments, the new contaminant in the wastewater is DEET; the initial concentration of the new contaminant in the wastewater is 15 mg / L.

[0068] In some embodiments, the size of the microbubbles is 10-60 μm.

[0069] The embodiments of the present invention are further described below. The flat ceramic membrane used in the following embodiments was purchased from Shenzhen Zhongqing Environmental Technology Co., Ltd., and its material is α-Al₂O₃ with a pore size of 0.1-0.9 μm and a pure water flux of 300-500 L / (m²). 2 *h), applicable pH value is 1-14, applicable temperature range is -20~60℃, and operating pressure is -0.1~0.3MPa.

[0070] Example 1

[0071] Preparation of modified ceramic membranes:

[0072] (1) 2.4 mmol of CoCl2 and 2.4 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28% ammonia water to obtain a suspension;

[0073] (2) Add 0.28 g of nano silica to the suspension obtained in step (1) and stir at room temperature for 30 minutes;

[0074] (3) Add 16 mL of ethanol to the mixture obtained in step (2) and continue stirring for 30 minutes;

[0075] (4) The mixed solution obtained in step (3) is transferred to a 50 mL polytetrafluoroethylene high-pressure reactor and heated at 180°C for 24 hours for hydrothermal reaction;

[0076] (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, and retain the wet nanospheres (solid content 12±0.5 wt%) to obtain the MnCoSi catalyst with a molar ratio of Mn to Co of 1:1.

[0077] (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension.

[0078] (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% 3-aminopropyltriethoxysilane (APTES);

[0079] (8) The flat ceramic membrane obtained in step (7) is refluxed at 80°C for 2 h to graft amino groups onto the surface of the flat ceramic membrane.

[0080] (9) The flat ceramic membrane obtained in step (8) is rinsed three times with ethanol to remove the physical adsorption coupling agent 3-aminopropyltriethoxysilane (APTES).

[0081] (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion obtained in step (6) and place it in a vacuum impregnation device, and apply a vacuum pressure of -0.3 MPa for 2 h;

[0082] (11) The flat ceramic membrane obtained in step (10) is purged with nitrogen gas through the membrane pores;

[0083] (12) Place the flat ceramic membrane obtained in step (11) in a vacuum drying oven at 60°C and dry for 12 hours;

[0084] (13) The flat ceramic film obtained in step (12) is placed in a tube furnace and annealed at 250°C in a nitrogen atmosphere for 1 h (heating rate 2°C / min) to fix MnCoSi onto the flat ceramic film.

[0085] like Figure 1 As shown, a reactor for a high-efficiency ozone oxidation wastewater treatment method based on a ceramic membrane includes a reactor body 6 and a modified ceramic membrane 7 prepared above. The modified ceramic membrane 7 is placed inside the reactor body 6 as an aeration head, used to connect to an external ozone generator 3 to aerate ozone and generate micron-sized bubbles. Figure 1 In the example, the reactor also includes an oxygen cylinder 1, a pressure gauge and regulator 2, an ozone generator 3, an inlet ozone gas concentration detector 4, a mass flow meter 5, and an outlet ozone gas concentration detector 8. The oxygen cylinder 1 is connected to the ozone generator 3 via the pressure gauge and regulator 2 to supply oxygen to the ozone generator 3 to generate ozone. The ozone generator 3 is connected to the modified ceramic membrane 7 inside the reactor body 6 via the mass flow meter 5 to supply a predetermined flow rate of ozone to the modified ceramic membrane 7 for ozone aeration. The inlet ozone gas concentration detector 4 is connected between the ozone generator 3 and the mass flow meter 5 to detect the inlet ozone gas concentration. The outlet ozone gas concentration detector 8 is connected to the outlet of the reactor body 6 to detect the outlet ozone gas concentration.

[0086] Using this reactor, the high-efficiency ozone oxidation wastewater treatment method based on ceramic membrane includes: S1, adding wastewater into the reactor; S2, ozone aeration through the modified ceramic membrane to generate micron-sized bubbles, thereby removing new pollutants from the wastewater.

[0087] The degradation performance evaluation is as follows, where "modified ceramic membrane aeration reactor" refers to... Figure 1 The reactor shown uses the modified ceramic membrane 7 from Example 1 as the aeration head, producing ozone bubbles that are micron-sized, approximately 50 μm in size; "unmodified ceramic membrane aeration reactor" refers to the reactor with... Figure 1 In contrast, a reactor that replaces the modified ceramic membrane 7 with the same flat-plate ceramic membrane without any catalyst produces ozone bubbles at the micrometer level; "ordinary aeration reactor" refers to... Figure 1 In contrast, the reactor that removes the modified ceramic membrane 7 and uses a non-flat ceramic membrane aerator produces ozone bubbles in the millimeter range.

[0088] 500 mL of wastewater was added to a modified ceramic membrane aeration reactor (Example 1), an unmodified ceramic membrane aeration reactor (Comparative Example 1), and a conventional aeration reactor (Comparative Example 2) for continuous ozone aeration. The ozone inlet flow rate was adjusted to 100 mL / min, the ozone inlet pressure to 0.16 MPa, and the ozone inlet concentration to 15 mg / L. The initial concentration C0 of the new pollutant (DEET) in the wastewater was 15 mg / L. The curve showing the change in the ratio of the concentration Ct of the new pollutant (DEET) at sampling to the initial concentration C0 over time is shown below. Figure 2 As shown, after 10 minutes of aeration, the concentration of new pollutant (DEET) in the wastewater was measured to be reduced to 0 mg / L, the concentration of new pollutant (DEET) in the wastewater of the unmodified ceramic membrane aeration reactor was reduced to 6.8 mg / L, and the concentration of new pollutant (DEET) in the wastewater of the ordinary aeration reactor was reduced to 12 mg / L.

[0089] Compared to conventional aeration, ozone microbubble aeration increased the equilibrium concentration of ozone in the liquid phase by 1.53 to 3.25 times, thus increasing the apparent mass transfer rate by approximately 3 times. The ozone mass transfer experiment is as follows:

[0090] Indigo stock solution: Weigh 0.6216 g of potassium indigo trisulfonate and dissolve it in 1 L of ultrapure water. After complete dissolution, prepare an indigo solution of 1 mmol / L.

[0091] Phosphoric acid stock solution: Add a certain amount of concentrated phosphoric acid (mass fraction >85%) to ultrapure water to make the phosphoric acid concentration in the solution 0.5 mol / L and the pH of the phosphoric acid stock solution 2.

[0092] The specific procedure for the ozone mass transfer experiment was as follows: A certain volume of phosphate buffer was taken, and ultrapure water was added to bring the volume to 500 mL. After stirring evenly, the mixture was added to the ozone micron bubble aeration reactor of Example 1 or the ordinary aeration (i.e., ozone millimeter bubble aeration) reactor of Comparative Example 2 for continuous ozone aeration. Reaction solutions with pH values ​​of 5, 6, 7, and 8 were prepared respectively, and the phosphate buffer concentration was 10 mmol / L to maintain pH stability during the experiment. A 2 mL sample was taken at specific aeration times to determine the liquid-phase ozone concentration in the solution, thereby obtaining the apparent ozone mass transfer rate. Figure 3 As shown, under the same aeration conditions, compared to millimeter bubble aeration, ozone microbubble aeration exhibits superior ozone mass transfer performance under the same aeration time conditions. Figure 4As shown, at pH values ​​of 5, 6, 7, and 8, the liquid-phase equilibrium concentrations of ozone aerated by microbubble aeration reached 1.80, 1.15, 0.70, and 0.46 mg / L, respectively, which are 1.53–3.25 times that of millimeter bubble aeration. This indicates that ozone microbubble aeration based on ceramic membranes can significantly improve the ozone liquid-phase equilibrium concentration and enhance ozone utilization efficiency. Figure 5 As shown, at pH values ​​of 5, 6, 7, and 8, the apparent reaction rate of ozone microbubble aeration was 3.12, 3.35, 3.31, and 3.26 times that of millimeter bubble aeration, respectively. This indicates that microbubble aeration can accelerate the ozone gas-liquid mass transfer process. Combining the results of liquid-phase ozone equilibrium concentration and ozone mass transfer rate, it is evident that the ozone microbubbles generated by the modified ceramic membrane aeration based on this invention can significantly improve the ozone mass transfer effect, including the amount and efficiency of ozone gas-liquid transfer. This fully demonstrates the superiority of ozone microbubble aeration in gas-liquid mass transfer, which will help improve ozone utilization efficiency and enhance the ozone oxidation effect.

[0093] Example 2

[0094] Preparation of modified ceramic membranes:

[0095] (1) 3.2 mmol of CoCl2 and 1.6 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28% ammonia water to obtain a suspension;

[0096] (2) Add 0.28 g of nano silica to the suspension obtained in step (1) and stir at room temperature for 30 minutes;

[0097] (3) Add 16 mL of ethanol to the mixture obtained in step (2) and continue stirring for 30 minutes;

[0098] (4) The mixed solution obtained in step (3) is transferred to a 50 mL polytetrafluoroethylene high-pressure reactor and heated at 180°C for 24 hours for hydrothermal reaction;

[0099] (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, and retain the wet nanospheres (solid content 12±0.5 wt%) to obtain the MnCoSi catalyst with a molar ratio of Mn to Co of 1:2.

[0100] (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension.

[0101] (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% 3-aminopropyltriethoxysilane (APTES);

[0102] (8) The flat ceramic membrane obtained in step (7) is refluxed at 80°C for 2 h to graft amino groups onto the surface of the flat ceramic membrane.

[0103] (9) The flat ceramic membrane obtained in step (8) is rinsed three times with ethanol to remove the physical adsorption coupling agent 3-aminopropyltriethoxysilane (APTES).

[0104] (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion obtained in step (6) and place it in a vacuum impregnation device, and apply a vacuum pressure of -0.3 MPa for 2 h;

[0105] (11) The flat ceramic membrane obtained in step (10) is purged with nitrogen gas through the membrane pores;

[0106] (12) Place the flat ceramic membrane obtained in step (11) in a vacuum drying oven at 60°C and dry for 12 hours;

[0107] (13) The flat ceramic film obtained in step (12) is placed in a tube furnace and annealed at 250°C in a nitrogen atmosphere for 1 h (heating rate 2°C / min) to fix MnCoSi onto the flat ceramic film.

[0108] The reactor used for wastewater treatment in this example differs from that in Example 1 in that the modified ceramic membrane 7 used is the one prepared in Example 2. The degradation performance is evaluated as follows:

[0109] 500 mL of wastewater was added to a modified ceramic membrane aeration reactor (Example 2), an unmodified ceramic membrane aeration reactor (Comparative Example 1), and a conventional aeration reactor (Comparative Example 2) for continuous ozone aeration. The ozone inlet flow rate was adjusted to 100 mL / min, the ozone inlet pressure to 0.16 MPa, and the ozone inlet concentration to 15 mg / L. The initial concentration of the new pollutant (DEET) in the wastewater was 15 mg / L. The curve showing the change in the ratio of the concentration Ct of the new pollutant (DEET) at sampling to the initial concentration C0 over time is shown below. Figure 2 As shown; after 10 minutes of aeration, samples were taken and the concentration of new pollutant (DEET) in the wastewater was measured to be reduced to 0 mg / L, but the degradation rate was slightly lower than in Example 1. The concentration of new pollutant (DEET) in the wastewater of the unmodified ceramic membrane aeration reactor was reduced to 6.8 mg / L, and the concentration of new pollutant (DEET) in the wastewater of the ordinary aeration reactor was reduced to 12 mg / L.

[0110] Example 3

[0111] Preparation of modified ceramic membranes:

[0112] (1) 1.6 mmol of CoCl2 and 3.2 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28% ammonia water to obtain a suspension;

[0113] (2) Add 0.28 g of nano silica to the suspension obtained in step (1) and stir at room temperature for 30 minutes;

[0114] (3) Add 16 mL of ethanol to the mixture obtained in step (2) and continue stirring for 30 minutes;

[0115] (4) The mixed solution obtained in step (3) is transferred to a 50 mL polytetrafluoroethylene high-pressure reactor and heated at 180°C for 24 hours for hydrothermal reaction;

[0116] (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, and retain the wet nanospheres (solid content 12±0.5 wt%) to obtain the MnCoSi catalyst with a molar ratio of Mn to Co of 2:1.

[0117] (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension.

[0118] (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% 3-aminopropyltriethoxysilane (APTES);

[0119] (8) The flat ceramic membrane obtained in step (7) is refluxed at 80°C for 2 h to graft amino groups onto the surface of the flat ceramic membrane.

[0120] (9) The flat ceramic membrane obtained in step (8) is rinsed three times with ethanol to remove the physical adsorption coupling agent 3-aminopropyltriethoxysilane (APTES).

[0121] (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion obtained in step (6) and place it in a vacuum impregnation device, and apply a vacuum pressure of -0.3 MPa for 2 h;

[0122] (11) The flat ceramic membrane obtained in step (10) is purged with nitrogen gas through the membrane pores;

[0123] (12) Place the flat ceramic membrane obtained in step (11) in a vacuum drying oven at 60°C and dry for 12 hours.

[0124] (13) The flat ceramic film obtained in step (12) is placed in a tube furnace and annealed at 250°C in a nitrogen atmosphere for 1 h (heating rate 2°C / min) to fix MnCoSi onto the flat ceramic film.

[0125] The reactor used for wastewater treatment in this example differs from that in Example 1 in that the modified ceramic membrane 7 used is the one prepared in Example 3. The degradation performance is evaluated as follows:

[0126] 500 mL of wastewater was added to a modified ceramic membrane aeration reactor (Example 3), an unmodified ceramic membrane aeration reactor (Comparative Example 1), and a conventional aeration reactor (Comparative Example 2) for continuous ozone aeration. The ozone inlet flow rate was adjusted to 100 mL / min, the ozone inlet pressure to 0.16 MPa, and the ozone inlet concentration to 15 mg / L. The initial concentration of the new pollutant (DEET) in the wastewater was 15 mg / L. The curve showing the change in the ratio of the concentration Ct of the new pollutant (DEET) at sampling to the initial concentration C0 over time is shown below. Figure 2 As shown, after 10 minutes of aeration, samples were taken and the concentration of new pollutant (DEET) in the wastewater was measured to be reduced to 1.5 mg / L, the concentration of new pollutant (DEET) in the wastewater of the unmodified ceramic membrane aeration reactor was reduced to 6.8 mg / L, and the concentration of new pollutant (DEET) in the wastewater of the ordinary aeration reactor was reduced to 12 mg / L.

[0127] Example 4

[0128] Preparation of modified ceramic membranes:

[0129] (1) 1.2 mmol of CoCl2 and 3.6 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28% ammonia water to obtain a suspension;

[0130] (2) Add 0.28 g of nano silica to the suspension obtained in step (1) and stir at room temperature for 30 minutes;

[0131] (3) Add 16 mL of ethanol to the mixture obtained in step (2) and continue stirring for 30 minutes;

[0132] (4) Transfer the mixed solution obtained in step (3) to a 50 mL polytetrafluoroethylene high-pressure reactor and heat it at 180°C for 24 hours;

[0133] (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, and retain the wet nanospheres (solid content 12±0.5 wt%) to obtain the MnCoSi catalyst with a molar ratio of Mn to Co of 3:1.

[0134] (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension.

[0135] (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% 3-aminopropyltriethoxysilane (APTES);

[0136] (8) The flat ceramic membrane obtained in step (7) is refluxed at 80°C for 2 h to graft amino groups onto the surface of the flat ceramic membrane.

[0137] (9) The flat ceramic membrane obtained in step (8) is rinsed three times with ethanol to remove the physical adsorption coupling agent 3-aminopropyltriethoxysilane (APTES).

[0138] (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion obtained in step (6) and place it in a vacuum impregnation device, and apply a vacuum pressure of -0.3 MPa for 2 h;

[0139] (11) The flat ceramic membrane obtained in step (10) is purged with nitrogen gas through the membrane pores;

[0140] (12) Place the flat ceramic membrane obtained in step (11) in a vacuum drying oven at 60°C and dry for 12 hours;

[0141] (13) The flat ceramic membrane obtained in step (12) is placed in a tube furnace and annealed at 250°C in a nitrogen atmosphere for 1 h (heating rate 2°C / min) to fix the MnCoSi catalyst on the flat ceramic membrane.

[0142] The reactor used for wastewater treatment in this example differs from that in Example 1 in that the modified ceramic membrane 7 used is the one prepared in Example 4. The degradation performance is evaluated as follows:

[0143] 500 mL of wastewater was added to a modified ceramic membrane aeration reactor (Example 4), an unmodified ceramic membrane aeration reactor (Comparative Example 1), and a conventional aeration reactor (Comparative Example 2) for continuous ozone aeration. The ozone inlet flow rate was adjusted to 100 mL / min, the ozone inlet pressure to 0.16 MPa, and the ozone inlet concentration to 15 mg / L. The initial concentration of the new pollutant (DEET) in the wastewater was 15 mg / L. The curve showing the change in the ratio of the concentration Ct of the new pollutant (DEET) at sampling to the initial concentration C0 over time is shown below. Figure 2 As shown, after 10 minutes of aeration, the concentration of new pollutant (DEET) in the wastewater decreased to 4.5 mg / L, the concentration of new pollutant (DEET) in the wastewater of the unmodified ceramic membrane aeration reactor decreased to 6.8 mg / L, and the concentration of new pollutant (DEET) in the wastewater of the ordinary aeration reactor decreased to 12 mg / L.

[0144] This invention synthesizes a MnCoSi catalyst via a solvothermal method, and then modifies and vacuum impregnates it onto the surface and pores of a flat ceramic membrane. The catalyst loading and microbubble generation function are integrated into a single flat ceramic membrane, forming a synergistic mechanism of "microbubble mass transfer enhancement - catalyst interface enhancement". Using this modified ceramic membrane as a microbubble aerator, ozone gas is efficiently broken into microbubbles of 1-60 μm, significantly improving gas-liquid mass transfer efficiency. At the same time, the MnCoSi catalyst promotes ozone decomposition to generate highly active free radicals, achieving efficient removal of recalcitrant organic pollutants. For the removal of DEET in wastewater, the removal effect is better when the molar ratio of Mn to Co is 1:1 > 1:2 > 2:1 > 3:1.

[0145] The above description provides a further detailed explanation of the present invention in conjunction with specific / preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the concept of the present invention, and all such substitutions or modifications should be considered within the scope of protection of the present invention. In the description of this specification, the reference to terms such as "an embodiment," "some embodiments," "preferred embodiment," "example," "specific example," or "some examples," etc., indicates that the specific features, structures, materials, or characteristics described in connection with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples. Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for treating wastewater using high-efficiency ozone oxidation based on ceramic membranes, characterized in that, Includes the following steps: S1. Wastewater is added to the reactor, wherein the reactor includes a reactor body and a modified ceramic membrane. The modified ceramic membrane is placed in the reactor body as an aeration head for connection with an external ozone generator to aerate ozone and generate micron-sized bubbles. The modified ceramic membrane includes a flat ceramic membrane and a MnCoSi catalyst. The MnCoSi catalyst is fixedly loaded on the surface of the flat ceramic membrane and in the membrane pores. In the MnCoSi catalyst, the molar ratio of Mn to Co is in the range of (1~3):(1~2). S2. Ozone is aerated through the modified ceramic membrane to generate micron-sized bubbles, which remove new pollutants from the wastewater. The preparation of the modified ceramic membrane includes the following steps: (1) 1.2-3.2 mmol of CoCl2 and 1.6-3.6 mmol of MnCl2 were ultrasonically dispersed in a mixed solution consisting of 1.6 mL of deionized water and 8 mL of 28 wt% ammonia water to obtain a suspension; (2) Add 0.28 g of nano-silica to the suspension obtained in step (1) and stir at room temperature for a predetermined time; (3) Add 16 mL of ethanol to the mixed solution in step (2) and continue stirring for a predetermined time; (4) Transfer the mixed solution from step (3) to a reaction vessel for hydrothermal reaction; (5) Cool the mixed solution obtained in step (4) and wash it repeatedly with deionized water and ethanol to remove impurities, while retaining the wet nanospheres to obtain the MnCoSi catalyst; (6) The MnCoSi catalyst obtained in step (5) is dispersed in ethanol to prepare a 1 mg / mL dispersion suspension. (7) Immerse the flat ceramic membrane in an ethanol solution containing 5 wt% amino coupling agent; (8) The flat ceramic membrane obtained in step (7) is refluxed at the reflux temperature of ethanol for a predetermined time to graft amino groups onto the surface of the flat ceramic membrane; (9) The flat ceramic membrane obtained in step (8) is rinsed with ethanol to remove the physically adsorbed amino coupling agent; (10) Immerse the flat ceramic membrane obtained in step (9) in the dispersion suspension obtained in step (6) and place it in a vacuum impregnation device, apply a predetermined vacuum pressure and process for a predetermined time. (11) The pores of the flat ceramic membrane obtained in step (10) are purged with an inert atmosphere; (12) Dry the flat ceramic film obtained in step (11) under vacuum; (13) The flat ceramic membrane obtained in step (12) is annealed at 250-300°C in an inert gas atmosphere for 1-2 hours to fix the MnCoSi catalyst on the flat ceramic membrane to obtain the modified ceramic membrane.

2. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that, The material of the flat ceramic membrane is α-Al2O3, and the pore size of the membrane is 0.1-0.9 μm.

3. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that, In the MnCoSi catalyst, the molar ratio of Mn to Co is one of 1:1, 2:1, 3:1, or 1:

2.

4. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that: The predetermined time in steps (2) and (3) is 30 minutes each; The hydrothermal reaction in step (4) is carried out at a temperature of 180°C for 24 hours. The amino coupling agent in step (7) is 3-aminopropyltriethoxysilane; The reflux temperature in step (8) is 80℃, and the time is 2h; The vacuum pressure in step (10) is -0.3 MPa, and the processing time is 2 hours. In step (12), the product is dried in a vacuum drying oven at 60°C for 12 hours. In step (13), the tube furnace is annealed at 250°C for 1 hour.

5. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that: The ozone intake flow rate is 100 ml / min.

6. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that: The ozone intake pressure is 0.16 MPa.

7. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that: The ozone concentration in the air was 15 mg / L.

8. The wastewater treatment method based on ceramic membrane high-efficiency ozone oxidation as described in claim 1, characterized in that: The new pollutant in the wastewater is DEET; the initial concentration of the new pollutant in the wastewater is 15 mg / L.

9. The wastewater treatment method based on high-efficiency ozone oxidation using ceramic membranes as described in claim 1, characterized in that: The size of the microbubbles is 10-60 μm.

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