A porous metal oxide aeration plate for nano-ozone bubble generation and a method of manufacturing the same

Abstract

The present application relates to a kind of porous metal oxide aeration plate for nano ozone bubble generation and its preparation method, the porous metal oxide aeration plate is two-layer structure, lower layer is porous titanium plate support layer, aperture is 0.5~1.5 μm;Upper layer is uniform porous metal oxide layer, thickness is 0.5~1.5 μm, aperture is 50~500nm;The aeration plate generates nano bubble by direct aeration, improves mass transfer efficiency in the process of ozone absorption, improves ozone utilization in ozone oxidation or catalytic ozone oxidation process, reduces power consumption and operating cost.

Description

Technical Field

[0001] This invention relates to the field of nanobubble ozone oxidation water treatment technology, which can prepare nanobubble ozone bubbles, improve ozone mass transfer efficiency and organic matter removal efficiency in wastewater, and belongs to the field of new environmental functional materials. Specifically, it relates to a porous metal oxide aeration plate for generating nanobubble ozone bubbles and its preparation method. Background Technology

[0002] Nanobubble ozone oxidation technology is a promising technology for advanced wastewater treatment. It mainly addresses the problems of low mass transfer efficiency, low ozone utilization, and large dosage of ozone oxidation technology. By preparing nanobubbles, it improves ozone mass transfer efficiency and organic matter removal efficiency in wastewater, and reduces the cost of ozone oxidation technology in wastewater treatment.

[0003] Nanobubbles in water can be prepared using various methods; however, only the dispersed air method and the dissolved air release method are suitable for widespread application in practical water treatment engineering. Nanobubble devices prepared using these two methods require a low gas-liquid mixing ratio (not exceeding 10%). Generally, ozone accounts for only 10% of the gas exiting an ozone generator. Therefore, when the gas-liquid mixing ratio is low, a large amount of water and gas needs to be introduced into the nanobubble generator to obtain a sufficient ozone dosage. When wastewater is introduced into the nanobubble device, the fine particulate matter in the wastewater hinders the formation of nanobubbles. Directly introducing tap water into the nanobubble device is too costly. Therefore, using these two technologies to prepare ozone nanobubbles has very limited improvement on ozone oxidation efficiency and high power consumption. Furthermore, the bubbles produced by these two methods are mostly in the micrometer range in diameter. Additionally, these two technologies are prone to the problem of ozone decomposing into oxygen upon heating, thus losing its strong oxidizing properties.

[0004] Preparing nano-ozone bubbles through direct aeration using uniform nanoporous plates may overcome the aforementioned shortcomings. However, the mechanism for preparing nanobubbles through direct aeration using uniform nanoporous plates is complex, making the preparation of uniform nanoporous materials very challenging. Furthermore, the prepared materials need to possess excellent resistance to acids, alkalis, corrosion, and ozone oxidation; otherwise, they will be difficult to promote in practical engineering applications. Summary of the Invention

[0005] This invention provides a porous metal oxide aeration plate for generating nano-ozone bubbles, which can be applied to nano-bubble ozone oxidation technology, significantly improving ozone mass transfer efficiency and ozone oxidation utilization, enhancing organic matter removal, and reducing the operating cost of ozone oxidation technology.

[0006] In a first aspect, the present invention provides a porous metal oxide aeration plate for generating nano-ozone bubbles. The porous metal oxide aeration plate has a two-layer structure, the lower layer being a porous titanium plate support layer with a pore size of 0.5–1.5 μm; and the upper layer being a uniform porous metal oxide layer with a thickness of 0.5–1.5 μm and a pore size of 50–500 nm.

[0007] The porous titanium plate support layer has excellent mechanical properties, which can provide effective support for the porous nano metal oxide layer and improve the service life of the nano bubble porous metal oxide aeration plate.

[0008] The aeration plate generates nanobubbles through direct aeration.

[0009] The porous titanium plate support layer is filled with titanium dioxide.

[0010] The titanium dioxide is introduced into the porous titanium plate through vacuum induction and high-temperature calcination.

[0011] The vacuum degree of the vacuum induction method is 1×10⁻⁶. -4 Pa~4×10 -4 Pa, the high-temperature calcination temperature is 400-700℃. The processing time is 1-3 hours.

[0012] Traditional porous titanium plate substrates suffer from low mechanical strength due to their porous structure, which can affect the lifespan of aeration plates over long periods. This invention utilizes a vacuum-induced method to reduce the size of titanium dioxide sol to 0.5–1.5 μm and introduce it into a porous titanium plate. Simultaneously, after high-temperature calcination, the remaining titanium dioxide further contributes to pore size reduction, generating nanoscale bubbles during aeration. This effectively encapsulates the porous titanium plate, improving the strength of the porous metal oxide layer and preventing structural damage from direct airflow if the metal oxide layer is not strong enough. This enhances the mechanical properties of the porous metal oxide aeration plate, facilitating industrial application and extending its service life.

[0013] This invention uses a combination of template method and electrodeposition method to prepare uniform nanoporous metal oxides on porous titanium plate support layer.

[0014] The metal oxide is selected from one or more of copper oxide, lead oxide, and zinc oxide.

[0015] The template method refers to the process of self-assembling a polystyrene particle coating on a porous titanium plate support layer using a coating method with the help of solvent evaporation. Then, the porous titanium plate containing the polystyrene particle coating is used as the anode and immersed in the electrodeposition solution using an electrodeposition method. At this time, the electrodeposition solution can fully contact the inside and outside (surface and interior) of the polystyrene porous particles. After high-temperature calcination, the template agent polystyrene porous particles are removed, and a regular three-dimensional network pore structure is formed on the porous titanium plate support layer. During the interaction with metal oxides, a dense metal oxide layer is formed, and the metal oxide pore size is uniform, the structure is regular, and the metal oxide loading efficiency is high.

[0016] The electrodeposition solution includes metal nitrates, potassium fluoride, and nitric acid.

[0017] The metal nitrate is selected from one or more of Cu(NO3)2, Pb(NO3)2 and Zn(NO3)2.

[0018] The concentration of the metal nitrate is 0.1–1.0 mol / L, the concentration of the nitric acid is 0.1–1.0 mol / L, and the concentration of the potassium fluoride is 0.01–0.1 mol / L.

[0019] Potassium fluoride and nitric acid in the electrodeposition solution can increase the solubility of metal nitrates, allowing metal oxides to be deposited more uniformly on the porous titanium plate. Simultaneously, the addition of potassium fluoride facilitates the establishment of a potential gradient within the system, resulting in denser and more uniform metal oxide deposition.

[0020] Secondly, the present invention provides a method for preparing a porous metal oxide aeration plate with nano-ozone bubbles. First, a porous titanium plate support layer filled with titanium dioxide is prepared by vacuum induction and high-temperature calcination. Then, polystyrene is used as a template agent to coat the surface of the porous titanium plate support layer. Finally, a uniform nanoporous metal oxide aeration plate is prepared by electrodeposition.

[0021] Specifically, the steps include the following:

[0022] (1) Using vacuum induction and high-temperature calcination, titanium dioxide sol is pore-shrinked and filled into a porous titanium plate to obtain a porous titanium plate support layer.

[0023] The titanium dioxide sol is prepared by mixing tetrabutyl titanate and anhydrous ethanol in a volume ratio of 1:3 to 1:5, adding the mixture dropwise to a mixed solution of anhydrous ethanol and nitric acid with a pH of 3 to 4, and stirring vigorously for 2 to 5 hours to form a pale yellow transparent sol.

[0024] The size of the titanium dioxide sol was reduced to 0.5–1.5 μm.

[0025] The vacuum degree of the vacuum induction method is 1×10⁻⁶. -4Pa~4×10 -4 Pa, wherein the high-temperature calcination temperature is 400-700℃ and the processing time is 1-3h.

[0026] (2) Coating a polystyrene coating onto a porous titanium plate support layer;

[0027] Porous polystyrene particles were ground, sieved, and ultrasonically dispersed in an ethanol solution to obtain a polystyrene dispersion. The polystyrene dispersion was uniformly coated onto the surface of the porous titanium plate support layer obtained in step (1), and allowed to stand and dry to obtain a porous titanium plate with a polystyrene coating.

[0028] The polystyrene dispersion has a mass fraction of 1-5%; the standing time is 24-48 hours, the drying temperature is 50-100℃, and the drying time is 12-24 hours.

[0029] Preferably, the polystyrene dispersion is coated 2 to 5 times.

[0030] Using porous polystyrene particles as a template agent increases the contact area between the metal salt solution and the polystyrene particles in the electrodeposition solution, allowing metal oxides to be densely deposited on the interior and outer surface of the porous particles, thereby improving the deposition efficiency of metal oxides.

[0031] Furthermore, the concentration of the polystyrene dispersion can be the same or different in each coating process; more preferably, the concentration of polystyrene used in each coating is different and gradually increases.

[0032] In one embodiment of the present invention, the PS concentration is 2% in the first coating process, 3% in the second coating process, 4% in the third coating process, and 5% in the fourth coating process.

[0033] Through multiple coating processes, a large-area, high-quality polystyrene microsphere particle coating can be obtained. This invention achieves gradient coating by adjusting the polystyrene concentration during the multiple coating processes, which facilitates the control of the dynamic balance of the interface during the self-assembly process, prevents particle deposition, and ultimately forms a regular, three-dimensional network pore structure after high-temperature calcination to remove the template, which is beneficial for the loading and deposition of metal oxides.

[0034] (3) Using the electrodeposition method, porous metal oxides are deposited on the porous titanium plate with polystyrene coating obtained in step (2) to obtain nano ozone bubble porous metal oxide aeration plate.

[0035] The electrodeposition method uses a porous titanium plate with a polystyrene coating obtained in step (2) as the anode, and deposits metal oxides onto the porous titanium plate under the action of a constant current in the electrodeposition solution. The cathode is a Ti plate.

[0036] The electrodeposition temperature is 60–80℃, the electrodeposition time is 40–60 min, and the current condition is 20–40 mA·cm. -2 .

[0037] The electrodeposition solution includes metal nitrates, nitric acid, and potassium fluoride.

[0038] The electrodeposition solution contains metal nitrates with a concentration of 0.1–1.0 mol / L, selected from one or more of Cu(NO3)2, Pb(NO3)2, and Zn(NO3)2.

[0039] The concentration of nitric acid is 0.1–1.0 mol / L, and the concentration of potassium fluoride is 0.01–0.10 mol / L.

[0040] In one embodiment of the present invention, the preparation method is as follows:

[0041] (1) Select a porous titanium plate with a pore size of 0.5–1.5 μm and a thickness of 1–5 mm. Place the cleaned porous titanium plate in a sealed vacuum-induced reactor (or vacuum furnace) at a vacuum degree of 2 × 10⁻⁶. -4 Under the conditions of Pa, temperature of 400-700℃, and treatment time of 1-3h, titanium dioxide sol is introduced into the fine channels of porous titanium plate by vacuum induction, and then dried at 80-120℃ to obtain a porous titanium plate support layer filled with titanium dioxide gel.

[0042] (2) Disperse porous polystyrene particles in an ethanol solution to obtain a polystyrene dispersion, uniformly coat the surface of the porous titanium plate support layer obtained in step (1), let stand for 24 to 48 hours, put it in a vacuum oven, and dry it at 50 to 100°C to obtain a porous titanium plate with a polystyrene coating.

[0043] (3) Using the porous titanium plate with polystyrene coating obtained in step (2) as the anode and the Ti plate as the cathode, at 20–40 mA·cm -2 Under constant current, the electrodeposition solution was electrodeposited in a water bath at 60–80°C for 40–60 min. After the electrodeposition was completed, it was removed and soaked in tetrahydrofuran solvent for 12–48 h, dried, and calcined at 300–500°C for 4–8 h to finally obtain a nano-ozone bubble porous metal oxide aeration plate.

[0044] A third aspect of the present invention provides an application of a porous metal oxide aeration plate generated by nano ozone bubbles in water treatment.

[0045] The beneficial effects of this invention are:

[0046] 1. The aeration material plate provided by this invention uses a porous titanium plate as the substrate. First, titanium dioxide gel is pore-filled into the porous titanium plate to obtain a support layer. Then, a PS template layer is coated on the surface, and an electrodeposition method is used to obtain a porous metal oxide aeration plate with more uniform and dense deposition by means of porous PS particle template agent. The preparation process is advanced and feasible. The aeration plate can construct a direct aeration technology to generate ozone nanobubbles, thereby improving the mass transfer efficiency in the ozone absorption process, increasing the ozone utilization rate in ozone oxidation or catalytic ozone oxidation processes, and reducing power consumption and operating costs.

[0047] 2. This invention utilizes a vacuum induction method to reduce the size of titanium dioxide sol to 0.5–1.5 μm by generating negative pressure in a vacuum and introduce it into a porous titanium plate. Simultaneously, after high-temperature calcination, the titanium dioxide sol further reduces the pore size, facilitating the generation of nanoscale bubbles during aeration. This also improves the mechanical strength of the porous metal oxide aeration plate, preventing direct air intake from impacting the metal oxide layer and damaging its structure, thereby extending the service life of the porous metal oxide aeration plate and facilitating industrial application.

[0048] 3. This invention optimizes the coating process of the template method. Through multiple coatings, a large-area, high-quality polystyrene microsphere particle coating can be obtained. At the same time, by utilizing the change in polystyrene concentration during the multiple coating processes, a gradient coating is formed to prevent PS particle deposition. After high-temperature calcination to remove the template, a regular three-dimensional network pore structure is finally formed, which is conducive to the loading and deposition of metal oxides. Meanwhile, the resulting porous oxides have uniform pore size and a more regular structure.

[0049] 4. In the electrodeposition process of this invention, potassium fluoride and nitric acid in the electrodeposition solution can increase the solubility of metal nitrates, so that metal oxides can be deposited more uniformly on the porous titanium plate; at the same time, the addition of potassium fluoride is conducive to establishing a potential gradient in the system, making the metal oxide deposition more dense and uniform.

[0050] 5. The nano-ozone bubble porous metal oxide aeration plate of the present invention has the advantages of uniform nanoporous structure, high porosity, acid and alkali resistance, corrosion resistance, ozone oxidation resistance, and high strength.

[0051] 6. The porous metal oxide aeration plate for nano-ozone bubbles of the present invention can be placed in an ozone oxidation or catalytic ozone oxidation reactor, and connected to the outlet of an ozone generator to directly generate ozone nanobubbles, controlling the bubble diameter to the nanometer level. This can significantly improve the gas-liquid mass transfer efficiency of ozone, and does not have the problem of low water-to-gas ratio, nor does it cause problems such as ozone decomposition into oxygen upon heating or decreased ozone solubility upon temperature increase, thus having very broad application prospects. Attached Figure Description

[0052] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is a schematic diagram of the preparation process of the porous metal oxide aeration plate for directly generating ozone nanobubbles in Embodiment 2 of the present invention.

[0054] Figure 2 This is a schematic diagram of the porous metal oxide aeration plate structure for directly generating ozone nanobubbles according to the present invention.

[0055] Figure 3 A product image of a commercially available microporous ceramic aerator for Comparative Example 1;

[0056] Figure 4 Scanning electron microscope image of the nano-ozone bubble porous metal oxide aeration plate of Example 1;

[0057] Figure 5 The image shows a scanning electron microscope (SEM) image of a 2-nanometer ozone bubble porous metal oxide aeration plate for comparison. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0059] Example 1

[0060] A porous metal oxide aeration plate for nano-ozone bubbles includes the following steps:

[0061] (1) Tetrabutyl titanate and anhydrous ethanol were mixed in a volume ratio of 1:3 and added dropwise to a mixed solution of anhydrous ethanol and nitric acid with pH 3-4. The mixture was stirred vigorously for 3 hours to prepare a light yellow transparent titanium dioxide sol.

[0062] A porous titanium plate with a pore size of 1.0 μm and a thickness of 5 mm was selected. The cleaned porous titanium plate was placed in a sealed vacuum tube furnace and heated to a vacuum degree of 2 × 10⁻⁶. -4Pa, treated at 500℃ for 2 hours (firstly, the titanium dioxide sol is introduced into the fine pores of the porous titanium plate using vacuum induction, and then titanium oxide is obtained by high-temperature calcination), and dried at 80℃ to obtain a porous titanium plate support layer filled with titanium dioxide.

[0063] (2) The porous polystyrene particles were ground and sieved to obtain particles with a diameter of about 1.0 μm. They were ultrasonically dispersed in an ethanol solution to prepare a polystyrene dispersion with a mass fraction of 2%. The polystyrene dispersion was uniformly coated on the surface of the porous titanium plate support layer in step (1) and coated three times. After the first coating, the plate was left to stand for 2 hours. After the second coating, the plate was left to stand for 2 hours. After the third coating, the plate was left to stand for 24 hours. The plate was then placed in a vacuum oven and dried at 50°C to obtain a porous titanium plate with a polystyrene coating.

[0064] (3) Prepare a solution containing 0.5 mol / L copper nitrate, 0.5 mol / L nitric acid, and 0.02 mol / L potassium fluoride. Using the porous titanium plate with a polystyrene coating obtained in step (2) as the anode and the Ti plate as the cathode, an experiment was conducted at 30 mA·cm⁻¹. -2 Under constant current conditions, the electrodeposition solution was electrodeposited in a 60°C water bath for 60 min, then soaked in the organic solvent tetrahydrofuran for 24 h, dried, and calcined at 300°C for 4 h to remove the template agent polystyrene, finally obtaining a porous metal oxide CuO aeration plate for generating nano ozone bubbles.

[0065] Example 2

[0066] A porous metal oxide aeration plate for nano-ozone bubbles includes the following steps:

[0067] (1) Tetrabutyl titanate and anhydrous ethanol were mixed in a volume ratio of 1:4 and added dropwise to a mixed solution of anhydrous ethanol and nitric acid with pH 3-4. The mixture was stirred vigorously for 4 hours to prepare a light yellow transparent titanium dioxide sol.

[0068] A porous titanium plate with a pore size of 1.0 μm and a thickness of 5 mm was selected. The cleaned porous titanium plate was placed in a sealed vacuum tube furnace and heated to a vacuum degree of 2 × 10⁻⁶. -4 Pa, treated at 600℃ for 1h (firstly, the titanium dioxide sol is induced to shrink and enter the small channels of the porous titanium plate using vacuum induction, and then titanium oxide is obtained by high-temperature calcination), and dried at 100℃ to obtain a porous titanium plate support layer filled with titanium dioxide.

[0069] (2) The porous polystyrene particles were ground and sieved to obtain particles with a diameter of about 1.0 μm. They were ultrasonically dispersed in an ethanol solution to prepare a polystyrene dispersion with a mass fraction of 2%. The polystyrene dispersion was uniformly coated on the surface of the porous titanium plate support layer in step (1) and coated three times. After the first coating, the plate was left to stand for 2 hours. After the second coating, the plate was left to stand for 2 hours. After the third coating, the plate was left to stand for 24 hours. The plate was then placed in a vacuum oven and dried at 80°C to obtain a porous titanium plate with a polystyrene coating.

[0070] (3) Prepare an electrodeposition solution containing 0.5 mol / L lead nitrate, 0.5 mol / L nitric acid, and 0.02 mol / L potassium fluoride.

[0071] Using the porous titanium plate with polystyrene coating obtained in step (2) as the anode and the Ti plate as the cathode, at 30 mA·cm -2 The electrodeposition solution was subjected to constant current and electrodeposited in a 60°C water bath for 60 min. Then, it was soaked in the organic solvent tetrahydrofuran for 24 h, dried, and calcined at 400°C for 6 h to remove the template agent polystyrene, finally obtaining the nano-ozone bubble porous metal oxide PbO2 aeration plate.

[0072] Example 3

[0073] A porous metal oxide aeration plate for nano-ozone bubbles includes the following steps:

[0074] (1) Mix tetrabutyl titanate and anhydrous ethanol at a volume ratio of 1:5, and add dropwise to a mixed solution of anhydrous ethanol and nitric acid with pH 3-4. Stir vigorously for 4 hours to prepare a light yellow transparent titanium dioxide sol.

[0075] A porous titanium plate with a pore size of 1.5 μm and a thickness of 4 mm was selected. The cleaned porous titanium plate was placed in a sealed vacuum tube furnace and treated at a vacuum degree of 2 × 10-4 Pa and a temperature of 500 °C for 3 h. (First, the titanium dioxide sol was induced to shrink pores and enter the small channels of the porous titanium plate using vacuum induction, and then titanium dioxide was obtained by calcination.) The plate was dried at 120 °C to obtain a porous titanium plate support layer filled with titanium dioxide gel.

[0076] (2) The porous polystyrene particles were ground and sieved to obtain particles with a diameter of about 1.0 μm. They were ultrasonically dispersed in an ethanol solution to prepare a polystyrene dispersion with a mass fraction of 4%. The polystyrene dispersion was uniformly coated on the surface of the porous titanium plate support layer in step (1) twice. After the first coating, the plate was left to stand for 2 hours. After the second coating, the plate was left to stand for 24 hours. The plate was then placed in a vacuum oven and dried at 60°C to obtain a porous titanium plate with a polystyrene coating.

[0077] (3) Prepare an electrodeposition solution containing 0.4 mol / L zinc nitrate, 0.6 mol / L nitric acid, and 0.06 mol / L potassium fluoride.

[0078] Using the porous titanium plate with polystyrene coating obtained in step (2) as the anode and the Ti plate as the cathode, at 30 mA·cm -2 The electrodeposition solution was subjected to constant current and electrodeposited in a 60°C water bath for 60 min. Then, it was soaked in the organic solvent tetrahydrofuran for 36 h, dried, and calcined at 500°C for 5 h to finally obtain the nano-ozone bubble porous metal oxide ZnO aeration plate.

[0079] Example 4

[0080] The other steps are the same as in Example 1, except that potassium fluoride is not used in the electrodeposition solution in step (3):

[0081] Prepare a solution containing 0.5 mol / L copper nitrate and 0.5 mol / L nitric acid.

[0082] Using the porous titanium plate with polystyrene coating obtained in step (2) as the anode and the Ti plate as the cathode, at 30 mA·cm -2 Under constant current conditions, the electrodeposition solution was electrodeposited in a 60°C water bath for 60 min, then soaked in the organic solvent tetrahydrofuran for 24 h, dried, and calcined at 300°C for 4 h to remove the template agent polystyrene, finally obtaining a nano-ozone bubble porous metal oxide CuO aeration plate.

[0083] Example 5

[0084] The other steps are the same as in Example 1, except for the change in PS coating concentration in step (2):

[0085] (2) The porous polystyrene particles were ground and sieved to obtain particles with a diameter of approximately 1.0 μm. They were then ultrasonically dispersed in an ethanol solution to prepare polystyrene dispersions with mass fractions of 2%, 3%, and 4%, respectively. First, the 2% polystyrene dispersion was uniformly coated onto the surface of the porous titanium plate support layer from step (1) and allowed to stand for 2 hours. Then, the 3% polystyrene dispersion was coated onto the surface and allowed to stand for 2 hours. Next, the 4% polystyrene dispersion was coated onto the surface. After coating, the surface was allowed to stand for 24 hours and then placed in a vacuum oven to dry at 50°C to obtain a porous titanium plate with a polystyrene coating.

[0086] Example 6

[0087] The other steps are the same as in Example 2, except for the change in PS coating concentration in step (2):

[0088] (2) The porous polystyrene particles were ground and sieved to obtain particles with a diameter of approximately 1.0 μm. They were then ultrasonically dispersed in an ethanol solution to prepare polystyrene dispersions with mass fractions of 2%, 3.5%, and 5%, respectively. First, the 2% polystyrene dispersion was uniformly coated onto the surface of the porous titanium plate support layer from step (1) and allowed to stand for 2 hours. Then, the 3.5% polystyrene dispersion was coated onto the surface and allowed to stand for 2 hours. Finally, the 5% polystyrene dispersion was coated onto the surface and allowed to stand for 24 hours. The plate was then placed in a vacuum oven and dried at 50°C to obtain a porous titanium plate with a polystyrene coating.

[0089] Comparative Example 1

[0090] Commercially available microporous ceramic aerators: Flat titanium alloy aerators consist of titanium filter plates, stainless steel shells, stainless steel flanges, and aeration head rubber rings. The titanium filter plates are sintered from high-purity powder. The microporous pure titanium aeration heads are made primarily from industrial pure titanium powder, sintered at high temperature and under high vacuum. They have a uniform structure, micropore diameters of 0.22-100 μm, and porosity of 35%-50%. Product images are shown below. Figure 3 As shown.

[0091] Comparative Example 2

[0092] The other steps are the same as in Example 1, except that the PS coating step is omitted:

[0093] (1) Tetrabutyl titanate and anhydrous ethanol were mixed in a volume ratio of 1:3 and added dropwise to a mixed solution of anhydrous ethanol and nitric acid with pH 3-4. The mixture was stirred vigorously for 3 hours to prepare a light yellow transparent titanium dioxide sol.

[0094] A porous titanium plate with a pore size of 1.5 μm and a thickness of 5 mm was selected. The cleaned porous titanium plate was placed in a sealed vacuum tube furnace and heated to a vacuum degree of 2 × 10⁻⁶. -4 Pa was treated at 500℃ for 2 hours and then dried at 80℃ to obtain a porous titanium plate support layer filled with titanium dioxide gel.

[0095] (2) Prepare a solution containing 0.5 mol / L copper nitrate, 0.5 mol / L nitric acid, and 0.02 mol / L potassium fluoride. Using the porous titanium plate support layer obtained in step (1) as the anode and the Ti plate as the cathode, at 30 mA·cm -2 Under constant current conditions, the electrodeposition solution was electrodeposited in a 60°C water bath for 60 minutes to finally obtain an ozone bubble metal oxide CuO aeration plate.

[0096] Wastewater treatment performance testing:

[0097] Before treatment, the coking wastewater had the following characteristics: TOC (Total Organic Carbon) = 70 mg / L, COD (Chemical Oxygen Demand) = 250 mg / L, UV254 (macromolecular organic matter in water) = 0.13 L / mol·cm, and chlorine content = 100 mg / L. The nano-ozone bubble porous metal oxide aeration plate prepared in Examples 1-6, the commercially available microporous ceramic aerator of Comparative Example 1, and the ozone bubble metal oxide CuO aeration plate prepared in Comparative Example 2 were used. Under normal temperature and pressure, the ozone dosage was controlled at 80 mg·L. -1 ·h -1 After wastewater treatment for 1 hour, the removal rates of TOC, COD, UV254, and residual chlorine were tested, and the ozone utilization rate was calculated based on the concentrations at the ozone inlet and outlet. The average bubble size was determined using a zeta potential analyzer and a nanoparticle size analyzer. The test data are shown in Table 1.

[0098] Table 1 Wastewater Treatment Effectiveness Data

[0099]

[0100] As shown in Table 1, the nano-ozone bubble aeration plate prepared in this invention uses a porous titanium plate as a support layer and uniform porous polystyrene particles as a template agent. A uniform nano-metal oxide porous titanium plate is prepared by electrodeposition, generating nano-bubbles through direct aeration. The wastewater treatment effect is significant, with TOC removal rates exceeding 60%, COD removal rates exceeding 70%, UV254 removal rates reaching 99%, and residual chlorine removal rates reaching 99%, significantly better than the wastewater treatment effect of the existing commercial titanium aerator in Comparative Example 1. Furthermore, the average bubble particle size measurement shows that the bubbles generated by the nano-aeration plates in Examples 1-6 are all around 800 nm, and the pore size of the metal oxide in the nano-porous metal oxide aeration plate is approximately 300-500 nm.

[0101] As can be seen from Examples 1 and 4, the electrodeposition solution in Example 1 contains a mixed solution of metal salt, potassium fluoride and nitric acid, which is conducive to more dense and uniform metal oxide deposition. Therefore, the removal rates of TOC, COD, UV254 and residual chlorine are improved when the nano ozone bubble porous metal oxide aeration plate is used to treat sewage.

[0102] Data from Examples 1 and 5, and Examples 2 and 6, show that the polystyrene concentration changes during the coating process, creating a gradient coating that ultimately forms a more regular three-dimensional network pore structure. This enhances the interaction with the metal oxide, leading to denser deposition of the metal oxide. Therefore, the nano-ozone bubble porous metal oxide aeration plate is more effective in treating wastewater, while also achieving higher ozone utilization.

[0103] As can be seen from Example 1 and Comparative Example 2, Comparative Example 2 did not undergo a PS coating step; the porous titanium plate was directly electrodeposited, and the resulting porous metal oxide scanning electron microscope image is shown below. Figure 4 As shown, metal oxides cannot form regular pore structures, and the pore sizes are non-uniform (the circular regions are not uniform in size); while Figure 5 The scanning electron microscope images clearly show that the porous metal oxide formed in Example 1 has more uniform pore size (uniform size of circular regions) and more regular structure. Moreover, the metal oxide has higher deposition efficiency and denser deposition, resulting in higher ozone utilization and better wastewater treatment effect.

[0104] The above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and are not intended to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the scope of the technology disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. A porous metal oxide aeration plate for nano-ozone bubble generation, characterized by, The porous metal oxide aeration plate is a two-layer structure, the lower layer is a porous titanium plate support layer with a pore size of 0.5-1.5 μm, and the upper layer is a uniform porous metal oxide layer with a thickness of 0.5-1.5 μm and a pore size of 50-500 nm; the aeration plate generates nanobubbles through direct aeration; the porous titanium plate support layer is filled with titanium dioxide, and the titanium dioxide is introduced into the porous titanium plate by a vacuum induction method and a high-temperature calcination method.

2. The porous metal oxide aerator plate of claim 1, wherein, The metal oxide is selected from one or more of copper oxide, lead oxide and zinc oxide.

3. A method for the preparation of a porous metal oxide aeration plate for nano- ozone bubble generation, characterized by, First, a porous titanium plate support layer filled with titanium dioxide is prepared by a vacuum induction method and a high-temperature calcination method, then polystyrene is used as a template agent to coat the surface of the porous titanium plate support layer, and finally a uniform nanoporous metal oxide aeration plate is prepared by electrodeposition.

4. The production method according to claim 3, wherein Specifically, the method comprises the following steps: (1) The titanium dioxide sol is shrunk and filled into the porous titanium plate by a vacuum induction method and a high-temperature calcination method to obtain the porous titanium plate support layer; (2) The porous polystyrene particles are ground, sieved and ultrasonically dispersed in an ethanol solution to obtain a polystyrene dispersion liquid; the polystyrene dispersion liquid is uniformly coated on the surface of the porous titanium plate support layer obtained in step (1), and then left to stand and dried to obtain a porous titanium plate containing a polystyrene coating layer; (3) A porous metal oxide is deposited on the porous titanium plate containing a polystyrene coating layer obtained in step (2) by electrodeposition to obtain a porous metal oxide aeration plate for nanometer ozone bubble generation.

5. The production method according to claim 4, wherein In step (1), the titanium dioxide sol is prepared by mixing tetrabutyl titanate and anhydrous ethanol at a volume ratio of 1:3-1:5, adding a mixed solution of anhydrous ethanol and nitric acid with a pH of 3-4 drop by drop, and stirring vigorously for 2-5 hours to obtain a light yellow transparent sol; The size of the titanium dioxide sol is reduced to 0.5-1.5 μm; The vacuum degree of the vacuum induction method is 1x10 -4 Pa~4x10 -4 Pa, the processing time is 1~3h, and the high-temperature calcination temperature is 400~700℃.

6. The production method according to claim 4, wherein In step (2), the mass fraction of the polystyrene dispersion liquid is 1-5%, the standing time is 24-48 hours, the drying temperature is 50-100 ℃, and the drying time is 12-24 hours.

7. The production method according to claim 6, wherein In step (2), the polystyrene dispersion liquid is coated 2-5 times, and the concentration of polystyrene used in each coating is different and gradually increases.

8. The production method according to claim 4, wherein In step (3), the porous titanium plate containing a polystyrene coating layer obtained in step (2) is used as an anode, and a metal oxide is deposited on the porous titanium plate under the action of a constant current in an electrodeposition solution; The electrodeposition temperature is 60-80℃, the electrodeposition time is 40-60 min, and the current condition is 20-40 mA·cm -2 ; The electrodeposition solution comprises a metal nitrate, potassium fluoride and nitric acid; The concentration of the metal nitrate is 0.1-1.0 mol / L, the concentration of the nitric acid is 0.1-1.0 mol / L, and the concentration of the potassium fluoride is 0.01-0.1 mol / L; The metal nitrate is selected from one or more of Cu(NO3)2, Pb(NO3)2 and Zn(NO3)2.

9. Use of the porous metal oxide aeration plate for nanometer ozone bubble generation according to any one of claims 1-2 or prepared by the method according to any one of claims 3-8 in water treatment.

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