A photocured alumina-based ceramic slurry and alumina-based ceramic

Abstract

The application discloses a photocured alumina-based ceramic slurry and an alumina-based ceramic. Al2O3, La2O3 and ammonium metatungstate are mixed, ball-milled, dried and sieved to obtain ceramic powder; the ceramic powder is mixed with photosensitive resin, photoinitiator and dispersant to prepare a ceramic slurry; the ceramic slurry is formed into a green body with a honeycomb structure through photocuring 3D printing; and the green body is subjected to debinding and sintering treatment, WO3 is generated in situ on the surface and grain boundary of the green body in the sintering and cooling process, and La2O3 is used as a grain boundary pinning agent to inhibit abnormal grain growth, so that an alumina-based ceramic containing WO3 is finally obtained. 6+ The characteristic of the solid solubility decrease in Al2O3 makes W 6+ diffuse to the grain boundary and surface and generate WO3 in situ, and La2O3 is used as a grain boundary pinning agent to inhibit abnormal grain growth, so that an alumina-based ceramic containing WO3 is finally obtained. The alumina-based ceramic containing WO3 prepared by the application can realize efficient degradation of tetracycline, sulfamethoxazole and ofloxacin under visible light irradiation.

Description

Technical Field

[0001] This invention belongs to the field of ceramic preparation technology, and relates to a photocurable alumina-based ceramic slurry and alumina-based ceramic. Background Technology

[0002] In the field of catalysis, alumina ceramics are often used as catalyst dispersion supports due to their high mechanical strength, good thermal stability, high porosity, and large specific surface area. In practical applications, researchers use methods such as spraying, impregnation, or precipitation to load the active components of the catalyst onto the pores or surface of the alumina ceramic support, thereby constructing reaction systems with high catalytic activity. This structured catalyst can significantly increase the reaction contact area and improve the reaction rate.

[0003] However, the traditional alumina ceramic support preparation process (such as dry pressing and slip casting) heavily relies on the use of molds, which limits the shape and makes it difficult to manufacture structures with complex geometries. This restricts the design space of catalyst supports in terms of micro-hydrodynamic behavior regulation and mass transfer efficiency optimization.

[0004] Digital light processing (DLP) technology, based on the principle of surface projection photopolymerization, uses a dynamic mask to project two-dimensional images layer by layer onto the surface of a photosensitive resin, achieving precise molding of three-dimensional structures. This technology boasts significant advantages such as high molding speed, high printing accuracy, and the ability to manufacture arbitrarily complex structures, and has shown enormous application potential in the field of ceramic material molding in recent years. The preparation of alumina ceramic supports using DLP technology holds promise for overcoming the limitations of traditional molds and achieving synergistic optimization of the macroscopic structure and microscopic properties of catalysts.

[0005] In addition, although the method of uniformly spraying or depositing the active component of the catalyst onto the pores or surface of the alumina ceramic support is simple to operate, the loading of the active component is limited and it is difficult to meet the high activity requirements. Furthermore, the bonding force between the active component and the alumina matrix is ​​weak. During long-term use, it is easy to fall off due to the scouring of the reaction liquid flow, bubble disturbance or mechanical collision, which leads to a significant decrease in catalytic activity and affects the service life of the catalyst and the stability of the reaction system. Summary of the Invention

[0006] To address the problems and defects in the existing technology, a photocurable alumina-based ceramic slurry and alumina-based ceramic are proposed.

[0007] In a first aspect, the present invention provides a photocurable alumina-based ceramic slurry, wherein, by mass percentage, the ceramic slurry comprises: 17%~25% photosensitive resin, 2%~4% photoinitiator, 2%~4% dispersant, and the balance being ceramic powder;

[0008] The photosensitive resin is prepared by mixing hydroxyethyl methacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate and N-vinylpyrrolidone in a mass ratio of 9:6:10:2.

[0009] The photoinitiator is 2,4,6-trimethylbenzoyldiphenylphosphine oxide;

[0010] The dispersant is TEGO-685;

[0011] The ceramic slurry comprises, by mass percentage: 7%~8.9% La2O3, 1%~2.1% ammonium metatungstate, and the balance being Al2O3.

[0012] In a second aspect, the present invention provides an alumina-based ceramic prepared from the above-mentioned photocurable alumina-based ceramic slurry, wherein the alumina-based ceramic has a honeycomb structure;

[0013] The honeycomb structure is composed of hexagonal unit channels of the same size;

[0014] The alumina-based ceramic matrix contains WO3 generated in situ by ammonium metatungstate during sintering.

[0015] Furthermore, in the alumina-based ceramic provided by the present invention, the side length of the hexagonal unit channel is 900 μm and the thickness in the vertical direction is 1 mm.

[0016] Thirdly, the present invention provides a method for preparing the alumina-based ceramic, comprising: dispersing La2O3, ammonium metatungstate and Al2O3 sequentially in anhydrous ethanol, mixing by ball milling, drying, grinding and sieving to obtain ceramic powder; premixing photosensitive resin and dispersant, then adding ceramic powder and photoinitiator, mixing by intermittent ball milling to obtain ceramic slurry; printing the ceramic slurry into a green body using digital light processing technology; and degreasing and sintering the green body to obtain alumina-based ceramic.

[0017] Furthermore, in the method for preparing alumina-based ceramics provided by the present invention, the ball milling mixing speed for preparing the ceramic powder is 200~300 rpm and the time is 4h;

[0018] The drying temperature is 60~80℃, and the time is 10~12h.

[0019] Furthermore, in the method for preparing alumina-based ceramics provided by the present invention, the intermittent ball milling process includes: ball milling at a speed of 200-300 rpm for 1.5-2 hours and then stopping, and restarting the ball milling after the slurry has cooled to room temperature, repeating the operation to achieve a cumulative ball milling time of 6-8 hours.

[0020] Furthermore, in the preparation method of alumina-based ceramics provided by the present invention, the printing molding adopts a top-down photocuring layer-by-layer molding process;

[0021] The light source for photopolymerization is 385nm ultraviolet light, the thickness of a single printed layer is 10μm, and the exposure time of a single layer is 1s.

[0022] Furthermore, in the method for preparing alumina-based ceramics provided by the present invention, the degreasing includes: first heating to 350°C at a rate of 1°C / min and holding for 2 hours in an air atmosphere; then heating to 600°C at a rate of 1°C / min and holding for 2 hours.

[0023] Furthermore, in the preparation method of alumina-based ceramics provided by the present invention, the sintering includes: first heating to 900°C at a rate of 1.5°C / min and holding for 1 hour in an air atmosphere; then heating to 1350°C at a rate of 2°C / min and holding for 3 hours; and finally cooling to room temperature at a rate of 5°C / min.

[0024] Fourthly, the present invention provides the application of the alumina-based ceramic in the photocatalytic degradation of antibiotics in water, wherein the antibiotics are tetracycline and / or sulfamethoxazole and / or ofloxacin.

[0025] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages:

[0026] (1) In this invention, La2O3 is introduced into ceramic powder as a grain boundary pinning agent, which effectively inhibits excessive grain boundary migration and abnormal grain growth, so that the alumina-based ceramics containing WO3 prepared in Examples 4-6 maintain a high bulk density (1.42~1.49 g / cm³). 3 While maintaining a porosity of over 21%, the ceramic still retains channels for the diffusion of reactant molecules, allowing contaminants to enter the ceramic interior. The pinning effect of La2O3 further promotes the uniform distribution of WO3 on the channel surface, enabling more complete degradation of contaminants after they enter.

[0027] (2) In this invention, ammonium metatungstate is introduced into ceramic powder, utilizing W during the cooling process. 6+ The characteristic of decreasing solid solubility in Al2O3 makes W 6+ Gradually, it diffuses towards the grain boundaries and surface, thus generating WO3 in situ. This in-situ generation method results in a more uniform distribution and stronger binding of WO3, thus exhibiting superior performance in the photocatalytic degradation of antibiotics, and its catalytic performance decays more slowly during recycling.

[0028] (3) The present invention uses 3D printing technology to construct a ceramic skeleton with a planar honeycomb structure, and the regularly arranged hexagonal channels provide efficient mass transfer channels for the reactants.

[0029] (4) The WO3-containing alumina-based ceramics prepared by this invention possess excellent physical properties, dimensional accuracy, catalytic activity, and cycle stability. They exhibit significant technical advantages in environmental remediation fields such as antibiotic-contaminated water treatment, providing an effective technical path to solve the problem of balancing activity and stability in practical applications of photocatalytic materials. Detailed Implementation

[0030] The technical solution of the present invention will be described below with reference to embodiments. However, the present invention is not limited to the following embodiments. Unless otherwise specified, the experimental methods and detection methods described in each embodiment are conventional methods; unless otherwise specified, the reagents and materials can be purchased commercially.

[0031] Examples 1-3

[0032] Examples 1-3 provide alumina-based ceramic slurries.

[0033] The alumina-based ceramic slurry is composed of ceramic powder, photosensitive resin, photoinitiator, and dispersant according to the mass percentages shown in Table 2. The ceramic powder is composed of the matrix material Al2O3, the sintering aid La2O3, and the photocatalytically active precursor ammonium metatungstate according to the mass percentages shown in Table 1. The photosensitive resin is prepared by mixing hydroxyethyl methacrylate (HEMA), polyethylene glycol diacrylate (PEG(200)DA), trimethylolpropane triacrylate (TMPTA), and N-vinylpyrrolidone (NVP) in a mass ratio of 9:6:10:2. The photoinitiator is 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), and the dispersant is polyether siloxane copolymer (TEGO-685).

[0034] Table 1 Composition of ceramic powder

[0035]

[0036] Table 2 Composition of alumina-based ceramic slurry

[0037]

[0038] The preparation method of the alumina-based ceramic slurry is as follows:

[0039] La₂O₃ was pre-calcined at 800℃ for 2 hours to remove water of crystallization and hydroxides. La₂O₃ and ammonium metatungstate were weighed and dispersed in 8-10 mL of anhydrous ethanol to obtain a mixture. Al₂O₃ was then dispersed in the mixture and transferred to a planetary ball mill. The mixture was ball-milled at 300 rpm for 4 hours to obtain a final mixture. Zirconia balls (3-5 mm) were used as the milling media, with a ball-to-material ratio of 3:1. After milling, the mixture was placed in a drying oven and dried at 80℃ for 12 hours. After grinding, the powder was passed through a 200-mesh sieve to obtain ceramic powder.

[0040] HEMA, PEG(200)DA, TMPTA, and NVP were mixed in a mass ratio of 9:6:10:2 to obtain a photosensitive resin. The photosensitive resin was pre-mixed with a dispersant to obtain a mixed resin. Ceramic powder was gradually added to the mixed resin in 5-6 portions, stirring thoroughly after each addition to ensure uniform dispersion. Then, a photoinitiator was added to obtain a mixed slurry. The mixed slurry was transferred to a planetary ball mill and ball-milled using an intermittent process. Specifically, the milling was performed at 300 rpm for 2 hours, then stopped. After the slurry cooled to room temperature, it was ball-milled again. This process was repeated 4 times, accumulating a total milling time of 8 hours, to obtain an alumina-based ceramic slurry.

[0041] Comparative Example 1

[0042] This comparative example is the same as Example 1, except that, by mass percentage, the ceramic powder in this comparative example consists of 97.9% Al2O3 powder and 2.1% ammonium metatungstate.

[0043] Examples 4-6

[0044] Examples 4-6 provide methods for preparing alumina-based ceramics with photocatalytic activity (WO3).

[0045] The alumina-based ceramic slurry described in Examples 4-6 was formed into an alumina-based ceramic green body with a planar honeycomb structure using a 3D printer (PC5003A-50, Xi'an Dianyun Biotechnology Co., Ltd.) employing digital light processing (DLP) technology. The honeycomb structure is composed of hexagonal unit channels of the same size, with each hexagon having a side length of 900 μm and a vertical thickness of 1 mm. The dimensions of the honeycomb structure are 21.6 mm × 20.9 mm × 3.5 mm. The printing process uses a photopolymerization layer-by-layer process, employing 385 nm ultraviolet light for curing. Each layer is 10 μm thick, with an exposure time of 1 second per layer, and layers are accumulated from top to bottom to obtain the final green body. After printing, the surface of the green body is cleaned with alcohol to remove residual slurry and then allowed to air dry. The degreasing process includes: transferring the green body to a tube furnace, heating it to 350°C at a rate of 1°C / min and holding it for 2 hours in air, then heating it to 600°C at a rate of 1°C / min and holding it for 2 hours. The sintering process includes: heating it to 900°C at a rate of 1.5°C / min and holding it for 1 hour in air, then heating it to 1350°C at a rate of 2°C / min and holding it for 3 hours, then cooling it to room temperature at a rate of 5°C / min to obtain alumina-based ceramics containing WO3.

[0046] Comparative Example 2

[0047] This comparative example is the same as Example 4, except that the alumina-based ceramic containing WO3 in this comparative example is prepared from the ceramic slurry provided in Comparative Example 1.

[0048] Comparative Example 3

[0049] This comparative example is the same as Example 4, except that the green blanks in this comparative example were naturally cooled to room temperature after sintering.

[0050] Comparative Example 4

[0051] This comparative example is the same as Example 4, except that the green blank in this comparative example is a cube with dimensions of 21.6 × 20.9 × 3.5 mm.

[0052] Comparative Example 5

[0053] In this comparative example, the ceramic slurry contained 91.1% Al₂O₃ powder and 8.9% La₂O₃ powder, with the remaining composition the same as in Example 1. The obtained ceramic slurry was used to prepare alumina-based ceramics according to the method described in Example 4. 0.5 g of ammonium metatungstate was dissolved in 1 mL of deionized water to obtain an ammonium metatungstate solution. The alumina-based ceramics were immersed in the ammonium metatungstate solution using a vacuum impregnation method at 5 × 10⁻⁶ °C. 3 ~2×10 3The alumina-based ceramic was kept under negative pressure for 1 hour at an absolute pressure of Pa to allow the ammonium metatungstate solution to fully enter the open pores of the alumina-based ceramic. After removal, the surface moisture was wiped off, and the ceramic was dried at 120℃ for 8 hours to obtain alumina-based ceramic loaded with ammonium metatungstate. The alumina-based ceramic loaded with ammonium metatungstate was placed in a tube furnace and heated to 500℃ at a rate of 2℃ / min under air atmosphere, held at that temperature for 5 hours, and then allowed to cool naturally to obtain alumina-based ceramic containing WO3.

[0054] The WO3-containing alumina-based ceramics of Examples 4-6 and Comparative Examples 2-5 were placed in beakers and dried in an oven at 100°C. The dry weight M1 of the WO3-containing alumina-based ceramics was measured three times for each group, and the average value was taken. The WO3-containing alumina-based ceramics were labeled and placed in glass bottles, and deionized water was added until the WO3-containing alumina-based ceramics were completely submerged. After sealing the bottle, the glass bottle was connected to a vacuum pump, and a vacuum was drawn until no air bubbles were generated, then the vacuuming was stopped. The WO3-containing alumina-based ceramics were removed, and the buoyant weight M3 was measured, and the average value of the three measurements was taken. The WO3-containing alumina-based ceramics were removed, and the surface moisture was wiped off with filter paper. The wet weight M2 was measured, and the average value of the three measurements was taken. The formulas for calculating the open porosity (B) and bulk density (d) of the WO3-containing alumina-based ceramics are as follows:

[0055]

[0056]

[0057] In the formula, d 水 The density of water (g / cm³) 3 ).

[0058] Firing shrinkage rate refers to the percentage change in size of the green body before and after sintering. The measurement standard is HB5353.2-2004. The dimensions of each WO3-containing alumina-based ceramic green body and the sintered WO3-containing alumina-based ceramic were measured using a vernier caliper with an accuracy of 0.02 mm. The average of three measurements at different locations was taken for each direction. Three samples were randomly selected from each experiment for measurement. The formula for calculating the firing shrinkage rate (δ) is as follows:

[0059]

[0060] In the formula, L is the length (mm) of the alumina-based ceramic green body, and L1 is the length (mm) of the sintered alumina-based ceramic.

[0061] As shown in Table 3, the open porosity of the alumina-based ceramics containing WO3 in Examples 4-6 was 21.3%-22.9%, and the bulk density was 1.42-1.49 g / cm³. 3 Comparative Example 2 had an open porosity of 25.9% and a bulk density of 1.58 g / cm³.3 Examples 4-6 and Comparative Examples 2-5 all retained an open porosity of over 20%, demonstrating that the alumina-based ceramics possess channels for reactant molecules to diffuse into. Furthermore, the small differences in open porosity and bulk density among the samples indicate good consistency in the sintering process conditions. Meanwhile, Examples 4-6 exhibited superior photocatalytic degradation performance (Table 5). This is because La2O3, acting as a grain boundary pinning agent, segregated at the Al2O3 grain boundaries during high-temperature sintering, inhibiting excessive grain boundary migration and abnormal grain growth. This ensured that ammonium metatungstate was fully converted into WO3 during sintering and uniformly distributed on the channel surface, allowing for more complete degradation of contaminants upon entry. Comparative Example 2, lacking the pinning effect of La2O3, showed insufficient uniformity in the distribution of WO3 within the channels, resulting in relatively lower degradation performance.

[0062] Table 3. Open porosity and bulk density of alumina-based ceramics containing WO3

[0063]

[0064] As shown in Table 4, the alumina-based ceramics containing WO3 in Examples 4-6 showed little difference in firing shrinkage rates in the X, Y, and Z directions. For example, the firing shrinkage rates of the alumina-based ceramic containing WO3 in Example 4 were 1.32% (X), 2.17% (Y), and 1.17% (Z), respectively. The firing shrinkage rates of the alumina-based ceramic containing WO3 in Comparative Example 2 were higher in all directions than those in Examples 4-6, and fluctuated more significantly. Firing shrinkage rate is an intrinsic manifestation of the degree of densification during ceramic sintering. The above data indicate that the pinning effect of La2O3 effectively suppressed local overfiring and uneven shrinkage, ensuring the dimensional stability and structural integrity of the green body after sintering. Comparative Example 2, lacking the pinning effect of La2O3, had a higher shrinkage rate and significant anisotropy, easily leading to defects such as warping and cracking. This result further verifies the crucial role of La2O3 pinning agent in the ceramic firing process.

[0065] Table 4. Firing shrinkage rate of alumina-based ceramics containing WO3

[0066]

[0067] Three different standards—tetracycline (TC), sulfamethoxazole (SMZ), and ofloxacin (OLF)—were weighed into 10 mL volumetric flasks, dissolved in methanol, and diluted to a concentration of 500 mg / L. The solution was then stored at 4°C. The standard mixture was diluted to a concentration of 10 mg / L to form a mixed antibiotic solution. A 300 W xenon lamp equipped with a 420 nm cutoff filter was selected as the visible light source, with a distance of 11 cm between the reaction solution interface and the visible light source. The mixed antibiotic solution was placed in a reactor, and the WO3-containing alumina-based ceramic (21.6 mm × 20.9 mm × 3.5 mm) prepared in Examples 4 and Comparative Examples 2-5 was added. The mixture was stirred in the dark for 30 min to reach adsorption-desorption equilibrium, and then the light source was turned on to initiate the reaction. 1 mL of sample was taken every 10 min for a total of 60 min. The sample was filtered through a 0.22 μm nylon organic filter membrane, and the concentration intensity signal was obtained using the ion detection scanning mode of a high performance liquid chromatography-mass spectrometry instrument. The concentration change of antibiotic before and after light exposure was determined, and the peak area was used for quantification. The relative intensity (A / A0) was used to calculate (C / C0) as the degradation rate of antibiotics catalyzed by visible light.

[0068] Table 5. Degradation rate of antibiotics by alumina-based ceramics containing WO3

[0069]

[0070] As shown in Table 5, the alumina-based ceramic containing WO3 in Example 4 exhibited degradation rates of 98.31%, 87.75%, and 94.48% for TC, SMZ, and OLF, respectively, all significantly superior to the alumina-based ceramics containing WO3 in Comparative Examples 2-5. These results demonstrate that the present invention, by introducing ammonium metatungstate into the ceramic powder and utilizing the WO3 degradation rate during cooling... 6+ The characteristic of decreasing solid solubility in Al2O3 makes W 6+ Gradually diffusing towards grain boundaries and the surface, WO3 is generated in situ. This in-situ WO3 generation method, combined with the honeycomb structure of alumina-based ceramics, effectively improves the exposure of photocatalytic active sites and mass transfer efficiency. In Comparative Example 3, the alumina-based ceramic containing WO3, due to natural cooling after sintering, resulted in WO3... 6+ Due to insufficient time for diffusion to the surface and grain boundaries, WO3 formation was incomplete. In Comparative Example 4, the alumina-based ceramic containing WO3 lacked a honeycomb structure, limiting the contact between reactant molecules and active sites, resulting in low mass transfer efficiency. Although Comparative Example 5 also introduced WO3, its loading was limited, and the distribution of active components was not uniform, leading to degradation rates of 86.11%, 78.61%, and 87.91% for TC, SMZ, and OLF, respectively.

[0071] Taking SMZ as an example, the cyclic stability of the WO3-containing alumina-based ceramics prepared in Example 4 and Comparative Examples 2-5 was tested under five-cycle experiments.

[0072] Table 6 Cyclic stability of alumina-based ceramics containing WO3

[0073]

[0074] As shown in Table 6, after five cycles of repeated use, the degradation rate of SMZ in Example 4 only decreased slightly from 87.75% to 82.56%, demonstrating excellent photocatalytic degradation stability. In contrast, the degradation rate of Comparative Example 5 decreased sharply from 78.61% to 55.16%, with a decrease of 29.8%, indicating that the WO3 introduced by the vacuum impregnation method is very prone to detachment or deactivation during repeated use.

[0075] The embodiments described above are some, but not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art through related deductions and substitutions based on the inventive concept, without inventive effort, are within the scope of protection of the present invention.

Claims

1. An alumina-based ceramic, characterized in that, The alumina-based ceramic has a honeycomb structure; The honeycomb structure is composed of hexagonal unit channels of the same size; The alumina-based ceramic matrix contains WO3 generated in situ by ammonium metatungstate during sintering. The alumina-based ceramic is made of ceramic powder; by mass percentage, the ceramic powder comprises: 7%~8.9% La2O3, 1%~2.1% ammonium metatungstate, and the balance being Al2O3.

2. The alumina-based ceramic according to claim 1, characterized in that, The hexagonal unit channel has a side length of 900 μm and a thickness of 1 mm in the vertical direction.

3. The method for preparing alumina-based ceramics according to any one of claims 1 to 2, characterized in that, include: La2O3, ammonium metatungstate, and Al2O3 were sequentially dispersed in anhydrous ethanol, and after ball milling, drying, grinding, and sieving, ceramic powder was obtained. Photosensitive resin and dispersant were premixed, and then ceramic powder and photoinitiator were added. The mixture was then mixed using an intermittent ball milling process to obtain ceramic slurry. Digital light processing technology was used to print the ceramic slurry into a green body. After degreasing and sintering the green body, alumina-based ceramics are obtained; The ceramic slurry comprises, by weight percentage: 17%~25% photosensitive resin, 2%~4% photoinitiator, 2%~4% dispersant, and the balance being ceramic powder; The photosensitive resin is prepared by mixing hydroxyethyl methacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate and N-vinylpyrrolidone in a mass ratio of 9:6:10:

2. The photoinitiator is 2,4,6-trimethylbenzoyldiphenylphosphine oxide; The dispersant is TEGO-685.

4. The method for preparing alumina-based ceramics according to claim 3, characterized in that, The ball milling mixing speed for preparing the ceramic powder is 200~300 rpm, and the time is 4 hours. The drying temperature is 60~80℃, and the time is 10~12h.

5. The method for preparing alumina-based ceramics according to claim 3, characterized in that, The intermittent ball milling process includes: ball milling at a speed of 200-300 rpm for 1.5-2 hours, then stopping, and restarting the ball milling after the slurry has cooled to room temperature. This process is repeated until the cumulative ball milling time reaches 6-8 hours.

6. The method for preparing alumina-based ceramics according to claim 3, characterized in that, The printing process employs a top-down photocuring layer-by-layer molding process. The light source for photopolymerization is 385nm ultraviolet light, the thickness of a single printed layer is 10μm, and the exposure time of a single layer is 1s.

7. The method for preparing alumina-based ceramics according to claim 3, characterized in that, The degreasing process includes: heating to 350°C at a rate of 1°C / min and holding for 2 hours in an air atmosphere; then heating to 600°C at a rate of 1°C / min and holding for 2 hours.

8. The method for preparing alumina-based ceramics according to claim 3, characterized in that, The sintering process includes: heating to 900°C at a rate of 1.5°C / min and holding for 1 hour in an air atmosphere; then heating to 1350°C at a rate of 2°C / min and holding for 3 hours; and finally cooling to room temperature at a rate of 5°C / min.

9. The application of the alumina-based ceramic according to any one of claims 1 to 2 in the photocatalytic degradation of antibiotics in water, characterized in that, The antibiotics are tetracycline and / or sulfamethoxazole and / or ofloxacin.

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