Fe-MOFs / carrier type composite catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a Fe-MOFs / carrier type composite catalyst as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing acid-activated spherical gamma-Al2O3 with a terephthalic acid solution, and carrying out a first solvothermal reaction so that terephthalic acid is chemically anchored on the surface of gamma-Al2O3 to obtain gamma-Al2O3 loaded with H2BDC; and dissolving soluble ferric salt and gamma-Al2O3 loaded with H2BDC in a solvent, carrying out a second solvothermal reaction to coordinate Fe < 3 + > and H2BDC, and epitaxially growing MIL-101 (Fe) crystals on the surface of gamma-Al2O3 to obtain the Fe-MOFs / carrier type composite catalyst. The Fe-MOFs / carrier type composite catalyst is obtained by adopting a two-step solvothermal method, so that not only can the problem of recovery of the Fe-MOFs material be effectively solved, but also the catalytic performance can be improved through the synergistic effect between the carrier and MOFs.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water treatment, and particularly relates to a Fe-MOFs / support type composite catalyst, a preparation method and application thereof. BACKGROUND

[0002] Water pollution refers to that a certain amount of pollutants such as sewage and waste in a water body have exceeded the purification capacity of the water body, thereby changing the physicochemical properties and biological population structure of the water environment, destroying the original ecological environment and reducing the utilization value of the water. Among them, the pollution of antibiotic drugs in the water environment has become a major problem in the field of environmental protection. At present, the advanced oxidation method has good treatment effect on various pollutants in the treatment method of antibiotic wastewater, and has been widely applied in the field of water treatment,

[0003] The advanced oxidation method includes photocatalytic oxidation, ozone oxidation and Fenton oxidation and the like, and is suitable for antibiotic wastewater which is difficult to be treated by traditional methods, and the ozone oxidation method is a common degradation means in industry.

[0004] A catalyst is often introduced during ozone oxidation degradation, which improves the utilization efficiency and reaction rate of ozone. The catalyst can catalyze ozone cracking to generate active species with oxidation properties, so as to realize rapid degradation of pollutants. In recent years, MOFs-based catalysts have shown special advantages in catalyzing ozone, because their ordered pore structure and adjustable coordination environment provide an ideal place for ozone activation. Through the catalytic action of the metal center, MOFs can efficiently catalyze ozone decomposition to generate active oxygen species, and MOFs materials exhibit unique advantages in the field of catalytic ozone oxidation. MOFs contain precisely controlled metal types and ligand structures, which can be used to design the electronic structure and acid sites of the catalyst, so as to realize precise control of the reaction path. These characteristics promote MOFs to become an ideal catalyst for a new generation of efficient catalytic ozone.

[0005] Iron-based MOFs (Fe-based MOFs) are a type of MOFs material that has attracted special attention, and its performance in catalytic reactions is particularly outstanding. Iron, as a transition metal, has good catalytic activity, can promote the decomposition of ozone, and generate strong oxidizing •OH. Fe-MOFs not only have a high specific surface area and abundant active sites, but also become a research hotspot because of its low cost and environmental friendliness. However, the active components of Fe-MOFs are prone to agglomeration and have poor stability during preparation. SUMMARY

[0006] In order to solve the above problems, the application provides a Fe-MOFs / support type composite catalyst, a preparation method and application thereof. A two-step solvothermal method is adopted, spherical γ-Al2O3 is used as a carrier, an organic ligand is chemically anchored, and then Fe3+ The Fe-MOFs / Support type composite catalyst is obtained by loading MIL-101(Fe) on the spherical gamma-Al2O3, the uniform distribution of Fe elements on the surface of the support can effectively avoid the agglomeration of the active components, ensure the full exposure of the active sites in the composite catalyst, and the stability of the Fe-MOFs can be enhanced by the support, and the catalytic performance can be increased by the synergistic effect between the support and the MOFs.

[0007] The present application solves the above technical problems by the following technical scheme.

[0008] The first object of the present application is to provide a preparation method of Fe-MOFs / Support type composite catalyst, comprising the following steps: S1, mixing the acid-activated spherical gamma-Al2O3 and terephthalic acid solution to perform the first solvothermal reaction, so that the terephthalic acid is chemically anchored on the surface of the spherical gamma-Al2O3 to obtain the gamma-Al2O3 loaded with H2BDC.

[0009] S2, dissolving the soluble iron salt and the gamma-Al2O3 loaded with H2BDC in a solvent to perform the second solvothermal reaction, so that the Fe 3+ and H2BDC are coordinated, and the MIL-101(Fe) crystals are grown on the surface of the gamma-Al2O3 by epitaxy to obtain the Fe-MOFs / Support type composite catalyst.

[0010] Further, the molar mass ratio of terephthalic acid to acid-activated spherical gamma-Al2O3 in the terephthalic acid solution is 2mmol-8mmol:5g-30g, and the terephthalic acid solution is N,N-dimethylformamide solution of terephthalic acid.

[0011] Further, the molar ratio of terephthalic acid to Fe 3+ in the soluble iron salt in the terephthalic acid solution is 1-4:2-8, and the solvent is N,N-dimethylformamide.

[0012] Further, the temperature of the first solvothermal reaction is 100℃-120℃, and the time is 18h-22h.

[0013] Further, the temperature of the second solvothermal reaction is 100℃-120℃, and the time is 18h-22h.

[0014] Further, the specific method for acid activation of the spherical gamma-Al2O3 is: soaking the spherical gamma-Al2O3 in a hydrochloric acid solution, and performing acid activation at 65℃-75℃ for 2h-4h, and the mass concentration of the hydrochloric acid solution is 36%-38%.

[0015] The second objective of this invention is to provide a Fe-MOFs / supported composite catalyst, which is prepared using the above-described preparation method.

[0016] A third objective of this invention is to provide the application of the above-mentioned Fe-MOFs / supported composite catalyst in the catalytic ozone degradation of wastewater containing antibiotic drugs.

[0017] Further steps include: adding Fe-MOFs / supported composite catalyst into wastewater containing tetracycline antibiotics; using microbubble technology to introduce ozone into the wastewater in the form of microbubbles; and degrading the wastewater by the Fe-MOFs / supported composite catalyst catalyzing the microbubble ozone system at room temperature.

[0018] Compared with the prior art, the present invention has the following advantages: (2) The preparation method of the Fe-MOFs / supported composite catalyst provided by the present invention uses acid-activated spherical γ-Al2O3 as a support. During the first solvothermal reaction, the surface hydroxyl groups of acid-activated spherical γ-Al2O3 and the carboxyl groups of terephthalic acid undergo a dehydration condensation reaction to form stable covalent bonds, realizing the chemical anchoring of organic ligands on the support surface; during the second solvothermal reaction, Fe 3+ By coordinating with anchored H2BDC, MIL-101(Fe) crystals are epitaxially grown along the surface of the support to obtain a Fe-MOFs / support composite catalyst. The uniform distribution of Fe on the support surface effectively avoids the aggregation of active components, ensuring the full exposure of active sites in the composite catalyst. Furthermore, the support enhances the stability of Fe-MOFs, and the synergistic effect between the support and MOFs increases the catalytic performance. This plays an important role in improving the mass transfer efficiency and active site utilization of the material in the catalytic ozone oxidation process.

[0019] (3) This invention is based on Fe-MOFs materials. Fe-MOFs materials are loaded onto spherical γ-Al2O3 using chemical methods, effectively improving their physical properties and facilitating operation and application. γ-Al2O3, as a common catalyst support, possesses high specific surface area, good mechanical strength, and chemical stability. Furthermore, the spherical morphology of γ-Al2O3 facilitates filling and packing, making it suitable for large-scale operations in industrial applications, and thus it is widely used in the catalysis field. Loading Fe-MOFs onto γ-Al2O3 can solve the problem of difficult recovery of MOFs materials due to poor stability, and also enhance catalytic performance through the synergistic effect between the support and MOFs. Attached Figure Description

[0020] Figure 1 The reaction mechanism diagram for preparing the Fe-MOFs / supported composite catalyst of this invention is shown.

[0021] Figure 2 This is a diagram illustrating the ozone catalytic mechanism of the Fe-MOFs / supported composite catalyst of this invention.

[0022] Figure 3 The X-ray diffraction patterns are those of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 of this invention.

[0023] Figure 4 These are morphological images of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 of the present invention. Figure 4 In the figure, (a) is the blank carrier γ-Al2O3, (b) is MIL-101(Fe), (c) is Example 1, (d) is a partial enlarged view of (c), (e) is Example 2, (f) is Example 3, and (g) is Example 4.

[0024] Figure 5 The image shows the elemental composition and distribution characteristics of the MIL-101(Fe) / γ-Al2O3 composite catalyst prepared in Example 1 of this invention. Figure 5 In the figure, (a) shows the elemental surface scan morphology of Example 1, (b) shows the distribution of O element, (c) shows the distribution of Al element, (d) shows the distribution of Fe element, and (e) shows the content of each element.

[0025] Figure 6 The images show X-ray photoelectron spectroscopy (XPS) analysis of the catalysts prepared in Examples 1 to 4 of this invention. Figure 6 In the image, (a) is the full spectrum, (b) is the C1s spectrum, (c) is the Fe2P spectrum, and (d) is the O1s spectrum.

[0026] Figure 7 Specific surface area performance diagrams of the catalysts prepared in Examples 1 to 4 of this invention. Figure 7 In the figure, (a) shows the adsorption-desorption isotherms of MIL-101(Fe) / γ-Al2O3 under different carrier dosages during secondary hydrothermal treatment, and (b) shows the pore size distribution.

[0027] Figure 8 The images show the infrared spectra of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 of this invention.

[0028] Figure 9 The graph shows the degradation of TC by catalysts prepared with different carrier dosages at MIL-101(Fe) precursor liquid concentrations of 1 mmol, 2 mmol, 3 mmol and 4 mmol. Figure 9 (a) is 1 mmol, (b) is 2 mmol, (c) is 3 mmol, and (d) is 4 mmol.

[0029] Figure 10The degradation diagrams of TC by the catalysts prepared in Examples 1 and 6-8 of this invention are shown.

[0030] Figure 11 The graph shows the effect of different dosages of the catalyst prepared in Example 1 of this invention on TC degradation. Figure 11 In the figure, (a) shows the effect of catalyst dosage on TC degradation, and (b) shows the pseudo-first-order kinetic diagram.

[0031] Figure 12 The graph shows the effect of the catalyst prepared in Example 1 of this invention on the degradation of TC at different pH values ​​in wastewater. Figure 12 In the figure, (a) is the effect of pH on TC degradation, and (b) is the pseudo-first-order kinetic diagram.

[0032] Figure 13 The diagram shows the effect of the catalyst prepared in Example 1 of this invention on the degradation of TC under different coexisting anions.

[0033] Figure 14 This is a stability diagram of the catalyst prepared in Example 1 of the present invention.

[0034] Figure 15 The diagram shows the effect of the catalyst prepared in Example 1 of this invention on TC degradation in the presence of phosphate.

[0035] Figure 16 The graph shows the effect of the catalyst prepared in Example 1 of this invention on TC degradation under different free radical scavengers.

[0036] Figure 17 This diagram illustrates the effect of different dosages of ozone on TC degradation in the microbubble ozone system according to the present invention. Figure 17 In the figure, (a) is the degradation diagram of TC by catalyst dosage, and (b) is the pseudo-first-order kinetic diagram.

[0037] Figure 18 This diagram illustrates the effect of ozone concentration on TC degradation in a microbubble ozone system, as presented in this invention. Figure 18 In the figure, (a) is the graph of ozone concentration on TC degradation, and (b) is the pseudo-first-order kinetic graph.

[0038] Figure 19 This is a graph showing the degradation efficiency of the present invention in a microbubble ozone system at different initial TC concentrations. Figure 19 In the figure, (a) is the degradation diagram of the initial concentration of TC, and (b) is the pseudo-first-order kinetic diagram.

[0039] Figure 20 This is a graph showing the degradation efficiency of the present invention in a microbubble ozone system at different pH values. Figure 20 In the figure, (a) shows the effect of pH on TC degradation, and (b) shows the pseudo-first-order kinetic diagram.

[0040] Figure 21This is a stability diagram of the present invention in a microbubble ozone system.

[0041] Figure 22 This diagram illustrates the degradation of different tetracycline antibiotics in a microbubble ozone system according to the present invention. Figure 22 In the diagram, (a) is the degradation diagram of chlortetracycline, (b) is the pseudo-first-order kinetic diagram of chlortetracycline degradation, (c) is the degradation diagram of oxytetracycline, (d) is the pseudo-first-order kinetic diagram of oxytetracycline degradation, (e) is the degradation diagram of doxycycline, and (f) is the pseudo-first-order kinetic diagram of doxycycline degradation.

[0042] Figure 23 This diagram illustrates the degradation of mixed antibiotics in a microbubble ozone system according to the present invention. Figure 23 In the figure, (a) represents the COD removal rate and (b) represents the TOC removal rate. Detailed Implementation

[0043] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0045] On one hand, the present invention provides a method for preparing a Fe-MOFs / supported composite catalyst, comprising the following steps: S1. Mix acid-activated spherical γ-Al2O3 with terephthalic acid solution and carry out the first solvothermal reaction at 100℃~120℃ for 18h~22h to chemically anchor terephthalic acid on the surface of spherical γ-Al2O3, and obtain γ-Al2O3 loaded with H2BDC.

[0046] S2. Dissolve soluble iron salts and γ-Al2O3 loaded with H2BDC in a solvent, and carry out a second solvothermal reaction at 100℃~120℃ for 18h~22h, so that Fe 3+ By coordinating with H2BDC, MIL-101(Fe) crystals were epitaxially grown on the surface of γ-Al2O3 to obtain Fe-MOFs / supported composite catalysts.

[0047] This invention uses acid-activated spherical γ-Al₂O₃ as a support. During the first solvothermal reaction, the surface hydroxyl groups of the acid-activated spherical γ-Al₂O₃ and the carboxyl groups of terephthalic acid undergo a dehydration condensation reaction to form stable covalent bonds, thus achieving the chemical anchoring of organic ligands on the support surface. During the second solvothermal reaction, Fe… 3+ By coordinating with anchored H2BDC, MIL-101 (Fe) crystals are epitaxially grown along the support surface, ensuring a uniform distribution of Fe on the support surface. This effectively prevents the aggregation of active components and ensures sufficient exposure of active sites in the composite catalyst. This plays a crucial role in improving the mass transfer efficiency and active site utilization during the catalytic ozone oxidation process. The reaction mechanism diagram is shown below. Figure 1 As shown.

[0048] This invention is based on Fe-MOFs materials. Through a chemical method, Fe-MOFs are loaded onto spherical γ-Al₂O₃, effectively improving their physical properties and facilitating handling and application. γ-Al₂O₃, as a common catalyst support, possesses high specific surface area, good mechanical strength, and chemical stability. Furthermore, the spherical morphology of γ-Al₂O₃ facilitates filling and packing, making it suitable for large-scale industrial applications and thus widely used in catalysis. Loading Fe-MOFs onto γ-Al₂O₃ not only effectively solves the difficult recovery problem caused by the poor stability of Fe-MOFs materials but also enhances catalytic performance through the synergistic effect between the support and Fe-MOFs.

[0049] In some embodiments, the molar ratio of terephthalic acid to acid-activated spherical γ-Al₂O₃ in the terephthalic acid solution is 2 mmol–8 mmol: 5 g–30 g, and the terephthalic acid solution is an N,N-dimethylformamide solution of terephthalic acid. In this invention, terephthalic acid is dissolved in N,N-dimethylformamide and ultrasonically dispersed to complete solvent to obtain a terephthalic acid solution, with a molar volume ratio of terephthalic acid to N,N-dimethylformamide of 2 mmol–8 mmol: 30 mL. After the first hydrothermal reaction, after natural cooling, the solution is filtered, washed multiple times with DMF and ethanol, and dried at 70 °C for 24 h to obtain γ-Al₂O₃ loaded with H₂BDC.

[0050] In some embodiments, terephthalic acid in a terephthalic acid solution and Fe in a soluble iron salt 3+The molar ratio of the two components is 1–4:2–8, and the solvent is N,N-dimethylformamide. In this invention, the soluble iron salt is FeCl3·6H2O. The soluble iron salt and γ-Al2O3 supported on H2BDC are dissolved in N,N-dimethylformamide and magnetically stirred for 3 hours to ensure thorough mixing. Then, a second solvothermal reaction is carried out. After the reaction is completed, the components are centrifuged sequentially, washed multiple times with DMF and ethanol, and dried at 70°C for 24 hours to obtain the Fe-MOFs / supported composite catalyst.

[0051] In some embodiments, the acid activation of spherical γ-Al₂O₃ is specifically performed as follows: spherical γ-Al₂O₃ is immersed in a hydrochloric acid solution and activated at 70°C for 3 hours. The mass concentration of the hydrochloric acid solution is 36%–38%. The particle size of the spherical γ-Al₂O₃ is 2 mm–3 mm. Acid activation is performed using a water bath. After activation, the spherical γ-Al₂O₃ is filtered, washed repeatedly with distilled water, and dried in an oven at 70°C for 24 hours to obtain acid-activated spherical γ-Al₂O₃. This invention, through acid activation of spherical γ-Al₂O₃, significantly alters the coordination environment of aluminum ions on its surface, exposing more unsaturated coordination sites that combine with water molecules to form abundant surface hydroxyl groups.

[0052] The second objective of this invention is to provide a Fe-MOFs / supported composite catalyst, which is prepared using the above-described preparation method.

[0053] In addition, the present invention also provides the application of the above-mentioned Fe-MOFs / supported composite catalyst in the catalytic ozone degradation of wastewater containing antibiotic drugs.

[0054] In this invention, the catalytic performance of the MIL-101(Fe) / γ-Al2O3 composite material is attributed to its high Lewis acid sites and porosity. The γ-Al2O3 support provides a stable supporting framework and abundant surface hydroxyl groups. MIL-101(Fe) / γ-Al2O3 enhances the ozone adsorption and activation process through Lewis acid sites, while the mesoporous structure of the material creates a microenvironment conducive to pollutant enrichment and free radical transport, achieving synergistic degradation through adsorption and catalysis.

[0055] like Figure 2 As shown, when MIL-101(Fe) / γ-Al2O3 comes into contact with ozone, the active sites on the catalyst surface adsorb ozone molecules, and the Fe in MIL-101(Fe) 2+ The ozone layer provides Lewis acid sites, which have the ability to accept electrons. When an ozone molecule approaches these sites, it interacts with the iron ions at the center of the Lewis acid site, accepting electrons from the ozone molecule and causing it to decompose, generating •OH and •O. - Highly reactive species. The reaction continues in dependence on Fe. 2+and Fe 3+ The redox cycle, under the action of ozone gas, Fe 2+ Oxidized to Fe 3+ Fe 3+ It is then reduced back to Fe through various pathways. 2+ It continues to participate in the catalytic reaction, forming a cycle reaction, so that the reaction continues.

[0056] In some embodiments, the Fe-MOFs / supported composite catalyst, when catalyzing the ozone degradation of wastewater containing antibiotics, includes the following steps: adding the Fe-MOFs / supported composite catalyst to the wastewater containing tetracycline antibiotics, using microbubble technology to introduce ozone into the wastewater in the form of microbubbles, and degrading the wastewater by the Fe-MOFs / supported composite catalyst catalyzing the microbubble ozone system at room temperature.

[0057] In this invention, wastewater containing antibiotics, specifically tetracycline (TC), is injected into a reaction vessel at a concentration of 40 mg / L. A Fe-MOFs / carrier composite catalyst is added, and ozone is generated using an ozone generator. The ozone gas then enters a gas-liquid mixing pump, where it is efficiently dissolved with the circulating liquid in a mixing tank at a working pressure of 2.5 MPa. The thoroughly mixed ozone-saturated solution is released through a microporous aeration head, generating a uniform cluster of microbubbles, significantly increasing the gas-liquid contact surface area. The circulating liquid, containing tetracycline-containing antibiotic wastewater, is connected to the mixing tank via a return pipeline, forming a closed-loop circulation system for degradation.

[0058] The following specific examples will provide further explanation.

[0059] Example 1 A method for preparing an Fe-MOFs / supported composite catalyst includes the following steps: S1. Spherical γ-Al2O3 particles with a particle size of 2mm to 3mm were immersed in a 38% hydrochloric acid solution and acid-activated in a 70℃ water bath for 3 hours. After activation, the particles were filtered out, washed three times with distilled water, and then dried in a 70℃ oven for 24 hours to obtain acid-activated spherical γ-Al2O3.

[0060] S2. Weigh 4 mmol of terephthalic acid and dissolve it in 30 mL of N,N-dimethylformamide. Stir the solution with sonication until dissolved to obtain a terephthalic acid solution. Mix 20 g of acid-activated spherical γ-Al2O3 with the above terephthalic acid solution and place it in a high-pressure vessel in a Teflon reactor. Perform a solvothermal reaction at 110 °C for 20 h. After the reaction is completed, allow it to cool naturally, filter it, and wash it three times with DMF and ethanol in sequence. Then dry it in an oven at 70 °C for 24 h to obtain γ-Al2O3 loaded with H2BDC.

[0061] S3. Dissolve 1 mmol of FeCl3·6H2O and the γ-Al2O3 of H2BDC obtained in S2 in 80 mL of N,N-dimethylformamide. Stir magnetically for 3 h to ensure thorough mixing. Then place the mixture in a high-pressure vessel in a Teflon reactor and carry out a solvothermal reaction at 110 °C for 20 h. After the reaction is completed, allow it to cool naturally, filter, and wash three times with DMF and ethanol in sequence. Then dry it in an oven at 70 °C for 24 h to obtain the Fe-MOFs / supported composite catalyst.

[0062] Example 2 A method for preparing a Fe-MOFs / supported composite catalyst differs from the method in Example 1 in that the amount of acid-activated spherical γ-Al2O3 used in S2 is 5g.

[0063] Example 3 A method for preparing a Fe-MOFs / supported composite catalyst differs from the method in Example 1 in that the amount of acid-activated spherical γ-Al2O3 used in S2 is 10g.

[0064] Example 4 A method for preparing a Fe-MOFs / supported composite catalyst differs from the preparation method in Example 1 in that the amount of acid-activated spherical γ-Al2O3 used in S2 is 30g.

[0065] Example 5 A method for preparing a Fe-MOFs / supported composite catalyst differs from the preparation method in Example 1 in that the amount of acid-activated spherical γ-Al2O3 used in S2 is 30g.

[0066] Example 6 A method for preparing a Fe-MOFs / supported composite catalyst differs from the preparation method in Example 1 in that the amount of terephthalic acid used in S2 is 2 mmol.

[0067] Example 7 A method for preparing a Fe-MOFs / supported composite catalyst differs from the preparation method in Example 1 in that the amount of terephthalic acid used in S2 is 6 mmol.

[0068] Example 8 A method for preparing a Fe-MOFs / supported composite catalyst differs from the preparation method in Example 1 in that the amount of terephthalic acid used in S2 is 8 mmol.

[0069] Comparative Example 1 A method for preparing an Fe-MOF catalyst includes the following steps: S3. Dissolve 4 mmol of FeCl3·6H2O and 4 mmol of terephthalic acid in 80 mL of N,N-dimethylformamide and stir magnetically for 3 h to ensure thorough mixing. Then place the mixture in an autoclave in a Teflon reactor and carry out a solvothermal reaction at 110 °C for 20 h. After the reaction is completed, allow it to cool naturally, filter it, and wash it three times with DMF and ethanol in sequence. Then dry it in an oven at 70 °C for 24 h to obtain the MIL-101(Fe) catalyst.

[0070] The structure and properties of the Fe-MOFs / supported composite catalysts prepared in Examples 1 to 11 and the MIL-101(Fe) catalyst prepared in Comparative Example 1 were analyzed, and the results are as follows: Figure 3 The images show the X-ray diffraction patterns of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 of this invention. Figure 3 As shown, the XRD pattern of MIL-101(Fe) exhibits obvious characteristic diffraction peaks at 2θ = 9°, 10.2°, 16.6°, and 18.1°, which perfectly match the reported positions of MIL-101(Fe) in the literature, confirming the successful synthesis of the material. The blank support γ-Al₂O₃ shows typical characteristic peaks at 2θ = 14.3°, 27.4°, 39.6°, 50.8°, and 67.2°. With increasing support amount, the number of MIL-101(Fe) crystals per unit area gradually decreases. When 5g and 10g of support are added, no characteristic peaks of γ-Al₂O₃ appear, indicating that MIL-101(Fe) crystals have grown to the support surface and are present in a high concentration, completely covering the γ-Al₂O₃ surface. When the support amount increases to 20g and 30g, characteristic peaks of γ-Al₂O₃ gradually appear, indicating that the number of MIL-101(Fe) crystals per unit area is also gradually decreasing. The XRD patterns of the MIL-101(Fe) / γ-Al2O3 composites obtained with different amounts of support did not show obvious characteristic peaks of MIL-101(Fe). This may be because the content of MIL-101(Fe) in the composite system is very small. At the same time, most of the iron ions are adsorbed inside the support during the synthesis process, so that MIL-101(Fe) is formed inside the γ-Al2O3 support. The surface loading is extremely low, and its diffraction peaks are masked by γ-Al2O3, so they cannot be observed at the corresponding positions in the spectrum.

[0071] Figure 4 These are morphological images of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 of the present invention. Figure 4 In the figures, (a) shows the blank carrier γ-Al2O3, (b) shows MIL-101(Fe), (c) shows Example 1, (d) is a partial enlarged view of (c), (e) shows Example 2, (f) shows Example 3, and (g) shows Example 4.Figure 4 As shown in Figure (a), the surface morphology of the blank γ-Al₂O₃ support is relatively smooth with obvious porosity, which is beneficial for the growth of the supported catalyst and the adsorption of pollutants. Figure 4 As shown in (b), the crystal structure of pure MIL-101(Fe) is a concave regular octahedral structure. Figure 4 As shown in (c) and (d), the SEM morphology of MIL-101(Fe) / γ-Al2O3 in Example 1 is clearly visible. It is evident that the support surface becomes rough, and crystals form. The magnified images show that the particles exhibit a concave octahedral morphology, aggregated and distributed on the support surface, further demonstrating the successful growth of MIL-101(Fe) on the γ-Al2O3 surface. Figure 4 (e) to (g) show the SEM morphology of samples with carrier dosages of 5g, 10g and 30g, respectively. As the carrier dosage gradually increases, the MIL-101(Fe) crystals on the surface gradually become sparse. At 30g, no obvious MIL-101(Fe) crystals are visible on the surface, which is consistent with the XRD results.

[0072] Figure 5 The image shows the elemental composition and distribution characteristics of the MIL-101(Fe) / γ-Al2O3 composite catalyst prepared in Example 1 of this invention. Figure 5 In the diagram, (a) shows the elemental surface scan morphology of Example 1, (b) shows the distribution of O element, (c) shows the distribution of Al element, (d) shows the distribution of Fe element, and (e) shows the content of each element. Figure 5 As shown in (a), the material exhibits a uniform porous structure. This can be seen through the corresponding elemental surface scan. Figure 5 As shown in (b) to (e), the uniform distribution of O, Al, and Fe on the support surface can be clearly observed. The widespread presence of Al mainly originates from the γ-Al₂O₃ support itself, while the uniform distribution of Fe is of significant indicative importance: firstly, it confirms the successful loading of MIL-101(Fe) onto the γ-Al₂O₃ support; secondly, it indicates that Fe was present during the synthesis process. 3+ The coordination reaction with the organic ligand terephthalic acid proceeded effectively, forming MIL-101(Fe) crystals with a regular structure. Of particular note is the uniform distribution of Fe on the support surface, indicating that this preparation method effectively avoids the aggregation of active components, ensuring sufficient exposure of active sites in the composite material. This uniform component distribution plays a crucial role in improving the mass transfer efficiency and active site utilization during catalytic ozone oxidation, providing a structural basis for subsequent catalytic degradation experiments.

[0073] Figure 6The images show X-ray photoelectron spectroscopy (XPS) analysis of the catalysts prepared in Examples 1 to 4 of this invention. Figure 6 In the image, (a) is the full spectrum, (b) is the C 1s spectrum, (c) is the Fe 2P spectrum, and (d) is the O 1s spectrum. Figure 6 As shown in (a), Fe, C, O, and Al elements are present under different conditions; Figure 6 As shown in (b), two distinct anti-valence peaks are observed at 284.8 eV and 289.0 eV. These two peaks represent the C=C / CC and C=O valences of terephthalic acid during the synthesis of MIL-101(Fe), respectively. Figure 6 As shown in (c), the peaks at 725.8 eV and 711.9 eV are attributed to Fe2p 1 / 2 and Fe2p 3 / 2, respectively. Meanwhile, a peak for Fe(III) at 718.0 eV is readily observed. Figure 6 As shown in (d), two peaks at 531.9 eV and 530.3 eV were obtained, corresponding to the O=C in terephthalic acid and the O-Fe bond in the Fe-oxo cluster, respectively. These results demonstrate the successful fabrication of MIL-101(Fe) and further verify the successful loading of MIL-101(Fe) onto the γ-Al2O3 support.

[0074] Figure 7 Specific surface area performance diagrams of the catalysts prepared in Examples 1 to 4 of this invention. Figure 7 In the figure, (a) shows the adsorption-desorption isotherms of MIL-101(Fe) / γ-Al2O3 under different carrier dosages during secondary hydrothermal treatment, and (b) shows the pore size distribution. Figure 7 As shown in (a), the sample exhibits a Type IV isotherm in the IUPAC classification, indicating that the MIL-101(Fe) / γ-Al2O3 composite material is a mesoporous material. The specific surface area of ​​the blank γ-Al2O3 is 164.28 cm². 3 / g. The specific surface area of ​​samples prepared under different carrier dosages is shown in Table 1. (Combined with Table 1 and...) Figure 7 In Figure (b), as the carrier dosage increases, the specific surface area of ​​the sample first increases and then decreases slightly. Specifically, when the loading increases from 5g to 20g, the specific surface area increases from 171.57cm². 3 / g significantly increased to 210.05cm 3The specific surface area was 206.69 cm³ / g, indicating that increasing the carrier content may have promoted the expansion of the material's surface area. MIL-101(Fe) has a highly ordered porous structure, and γ-Al₂O₃ itself also has a certain porosity. During the composite process, the pore structures of MIL-101(Fe) and γ-Al₂O₃ interact, which may form new pores or expand existing pores, thereby increasing the specific surface area. However, when the carrier content was further increased to 30 g, the specific surface area decreased slightly to 206.69 cm³ / g. 3 The / g ratio may be due to the increased number of carriers and the larger unit area, preventing the quantitative amount of MIL-101(Fe) crystals from completely covering the surface. Incompletely reacted substances lead to partial blockage or accumulation of the material's surface structure. A larger specific surface area allows for the full exposure of surface active sites, increasing the opportunity for contact with ozone, accelerating the catalytic ozone reaction efficiency, and facilitating the catalytic degradation of pollutants by ozone.

[0075] Table 1 BET specific surface area and porosity Figure 8 The images show the infrared spectra of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 of this invention. Figure 8 As shown, MIL-101(Fe) at 552 cm⁻¹ -1 710cm -1 1386cm -1 1581cm -1 and 1689cm -1 A distinct characteristic peak is observed at nearby wavelengths. 710cm -1 The characteristic peak at 1386 cm⁻¹ mainly originates from the vibration of the CH bond in benzene; while the peak at 1386 cm⁻¹... -1 and 1581cm -1 The characteristic peak at 1689 cm⁻¹ can be attributed to the symmetric and asymmetric vibrations of the carboxyl group, respectively. -1 The characteristic peak at 552 cm⁻¹ is related to the C=O bond present in the terephthalic acid ligand, indicating the presence of continuous dicarboxyl group linkages. The terephthalic acid ligand was successfully introduced into MIL-101(Fe); -1 The characteristic peak at this location belongs to Fe-O in MIL-101(Fe), further confirming the interaction between the ligand and Fe. 3+The coordination structure between them. In the infrared spectrum of the MIL-101(Fe) / γ-Al2O3 composite material, characteristic peaks of MIL-101(Fe) were observed on the surface of the γ-Al2O3 support, indicating that the chemical structure of MIL-101(Fe) was successfully preserved in the composite material. Compared with pure MIL-101(Fe), the infrared absorption spectrum of the composite material showed no significant difference or shift. The decrease in MIL-101(Fe) content per unit area leads to the weakening of the peak value, which is the reason why the peak value decreases as the support increases.

[0076] The catalysts prepared in Examples 1 to 8 were used to catalyze the ozone degradation of wastewater containing tetracycline (TC). The ozone concentration was 1.2 mg / min, the TC concentration was 40 mg / L, the wastewater volume was 500 mL, the pH was 6, and the TC was catalyzed for ozone degradation at room temperature.

[0077] Figure 9 The graph shows the degradation of TC by catalysts prepared with different carrier dosages at MIL-101(Fe) precursor liquid concentrations of 1 mmol, 2 mmol, 3 mmol and 4 mmol. Figure 9 In the equation (a), the value is 1 mmol; in (b), it is 2 mmol; in (c), it is 3 mmol; and in (d), it is 4 mmol. Figure 9 As shown, the degradation effect of 20g carrier at four different precursor liquid concentrations was generally good, at 67.93%, 65.62%, 64.26%, and 64.06%, respectively. Meanwhile, comparing different precursor liquid concentrations with 20g carrier, it was found that 1mmol precursor liquid concentration showed the best degradation effect on TC. As the precursor liquid concentration gradually increased, the degradation efficiency decreased slightly before stabilizing with minimal difference. It can be considered that 1mmol precursor liquid is sufficient for 20g carrier. The degradation effect decreased after increasing the carrier to 30g, possibly because the increased carrier quantity meant that the surface could not be completely covered by MIL-101(Fe) crystals, leading to a decrease in degradation efficiency.

[0078] Figure 10 The graphs show the degradation of TC by the catalysts prepared in Examples 1 and 6-8 of this invention. Figure 10 As shown, the degradation efficiencies were 48.01%, 67.93%, 57.98%, and 54.99%, respectively. It can be considered that when the ligand concentration is low, the ligand modification is incomplete, hindering the subsequent growth of MIL-101(Fe) crystals, resulting in fewer crystal structures on the support surface and thus a lower degradation efficiency. Excessive ligand, on the other hand, inhibits the chemical bond connection between H2BDC and γ-Al2O3, leading to incomplete or no MOF growth on the support during secondary hydrothermal treatment. The optimal concentration of H2BDC for primary hydrothermal treatment can be determined to be 4 mmol.

[0079] The effect of the catalyst prepared in Example 1 on TC degradation was determined by adjusting the amount of catalyst prepared in Example 1. Figure 11 The graph shows the effect of different dosages of the catalyst prepared in Example 1 of this invention on TC degradation. Figure 11 In the diagram, (a) shows the effect of catalyst dosage on TC degradation, and (b) is a pseudo-first-order kinetic diagram. Figure 11 As shown in (a), the removal rate of TC did not fluctuate significantly with increasing catalyst dosage. The TC removal rates were 64.75%, 65.58%, 67.93%, and 68.28% when catalyst dosage was increased to 3g, 4g, 5g, and 6g, respectively. Higher catalyst content increased reaction porosity, leading to increased adsorption efficiency. Adding 3g, 4g, and 5g of catalyst slightly increased the degradation rate, while adding 6g of catalyst resulted in almost no increase. This indicates that the ozone concentration in the reaction system is fixed, and the metal ions on the catalyst surface reacting with it are within a certain range. Excessive catalyst dosage cannot further improve the degradation efficiency; 5g is the optimal catalyst dosage. Further analysis using pseudo-first-order kinetics... Figure 11 As shown in (b), the corresponding kinetic constants for catalyst dosages of 3g, 4g, 5g, and 6g are 0.05594 min. -1 0.05594min -1 0.05969min -1 0.06086min -1 In summary, the optimal dosage of MIL-101(Fe) / γ-Al2O3 catalyst for catalytic degradation of TC by ozone is 5g.

[0080] In Example 1, when the catalyst dosage was 5g, the pH of the wastewater was adjusted to 2, 4, 6, 8, 10, 12, and 14, and the catalytic performance of MIL-101(Fe) / γ-Al2O3 prepared in Example 1 for catalytic ozone degradation of TC was tested. Figure 12 The graph shows the effect of the catalyst prepared in Example 1 of this invention on the degradation of TC at different pH values ​​in wastewater. Figure 12 In the diagram, (a) shows the effect of pH on TC degradation, and (b) shows the pseudo-first-order kinetics. Figure 12As shown in (a), the higher the pH value, the higher the degradation efficiency of TC by MIL-101(Fe) / γ-Al2O3, indicating that the degradation effect of the entire reaction system is better under alkaline conditions. The degradation effect is poor at pH 2 and 4, with only 21.35% and 26.86% degradation within 50 min, respectively. With increasing pH, the degradation efficiency of TC increases under neutral and alkaline conditions, which is beneficial to the degradation of TC by MIL-101(Fe) / γ-Al2O3. At pH=6, the initial pH value for TC, the degradation rate reaches 67.93%. Increasing the pH value to pH=8, 10, 12, and 14 further increases the degradation efficiency, to 65.64%, 68.25%, 70.74%, and 72.78%, respectively, showing a slight increase. Further analysis using pseudo-first-order kinetics... Figure 12 As shown in (b), the kinetic constants are 0.01048 min at pH = 2, 4, 6, 8, 10, 12 and 14. -1 0.01435min -1 0.05544min -1 0.05403min -1 0.05403min -1 0.05839min -1 and 0.0604min -1 In summary, MIL-101(Fe) / γ-Al2O3 is suitable for neutral and alkaline environments.

[0081] Figure 13 This diagram illustrates the effect of the catalyst prepared in Example 1 of this invention on TC degradation under different coexisting anions. Figure 13 As shown, SO4 2- When added to the reaction solution, TC only degraded by 40.91% under the same conditions. This may be because SO4... 2- It reacts with ozone to generate sulfate radicals (•SO4), which have certain oxidizing properties. - However, its oxidizing power is much lower than that of •OH, due to •SO4 - The reaction with •OH consumes some free radicals, thus reducing the TC degradation rate. The presence of nitrate ions in the reaction solution also leads to a decrease in TC degradation efficiency, with a degradation efficiency of 48.34%. This may be due to NO3-. - The presence of ions alters the original reaction pathway of •OH, thus affecting TC degradation. The TC degradation efficiency is 54.06% in the presence of carbonate ions. 2- It reacts with •OH, rapidly consuming •OH and causing the free radical chain reaction to be interrupted, generating carbonate free radicals (•CO3). - •CO3 -Its oxidizing power is also far less than that of •OH, failing to maximally oxidize TC molecules, resulting in a reduced degradation rate. Furthermore, CO3... 2- It may also alter the pH of the solution through buffering, further affecting the ozone decomposition pathway and reaction efficiency. When an equal amount of chloride ions is added to the solution, the degradation efficiency of TC decreases to 55.58%, due to the reduction in chloride ions. - The reaction with •OH consumes some free radicals, generates chlorinated byproducts, and increases the complexity of the reaction system. - It may also bind to the catalyst surface through complexation, affecting the activity of MIL-101(Fe) / γ-Al2O3.

[0082] Figure 14 This is a stability graph of the catalyst prepared in Example 1 of the present invention. Figure 14 As shown, after five consecutive cycles, the catalyst activity level decreased by only about 7.38%, demonstrating that the MIL-101(Fe) / γ-Al2O3 composite material has extremely high stability and reusability.

[0083] Figure 15 This is a graph showing the effect of the catalyst prepared in Example 1 of this invention on TC degradation in the presence of phosphate. Figure 15 As shown, the presence of phosphate significantly hinders the catalytic degradation of TC by ozone. Firstly, the adsorption of MIL-101(Fe) / γ-Al2O3 in the adsorption reaction decreases, indicating that the addition of phosphate inhibits the mass transfer characteristics of the catalyst. This is because phosphate may alter the catalyst's porosity and planarity. The interaction between metal ions and Lewis base sites leads to a reduction in •OH, inhibiting catalytic activity and resulting in a decrease in TC degradation efficiency. The TC degradation efficiency at 50 min was 43.58%, a decrease of 23.53%, meaning that phosphate occupies the surface Lewis acid sites on the catalyst, rendering them almost inactive and thus resulting in poor TC removal efficiency. Furthermore, since Na3PO4 is a strong phosphate, the removal of •OH through surface adsorption may also contribute to the decrease in TC degradation rate. Na2HPO4 and NaH2PO4 were also used as methods for further evaluating catalytic performance. At the same dosage (5 mg), Na2HPO4 and NaH2PO4 contained more free phosphate. In the same catalytic system, with the addition of Na2HPO4 and NaH2PO4 respectively, the degradation rates of TC in the catalytic system after 50 min were 53.9% and 40.9%, respectively. In conclusion, the Lewis acid sites on MIL-101(Fe) / γ-Al2O3 are the reason for the degradation of TC, which can decompose ozone into active substances to degrade TC.

[0084] Figure 16This diagram illustrates the effect of the catalyst prepared in Example 1 of this invention on TC degradation under different free radical scavengers. Conventional free radical quenching experiments were performed using tert-butanol (TBA) and p-benzoquinone (BQ). 5 mmol of each quencher was added during the reaction. Figure 16 As shown, tert-butanol is a strong quencher of •OH in the reaction solution. The addition of tert-butanol captures •OH adsorbed on the surface of MIL-101(Fe) / γ-Al2O3. The addition of tert-butanol reduced TC degradation to 46.02%. The aggregation of tert-butanol molecules on the catalyst surface reduces the opportunity for the catalyst to contact free •OH, leading to a weakened interaction between the catalyst and •OH, which is one of the reasons for the reduced catalytic activity. p-Benzoquinone is a typical superoxide radical (•O2). - The scavenger is capable of capturing •O2 in the reaction solution. - After adding p-benzoquinone to the solution, the degradation efficiency of TC by MIL-101(Fe) / γ-Al2O3 was only 14.49%, and ozone decomposition would produce •O2. - When a free radical is captured by p-benzoquinone, the free radical reaction chain is interrupted, and the captured •O2 - Unable to be converted into other active substances, the degradation reaction cannot proceed, hindering the degradation of the target pollutant. Therefore, in the MIL-101(Fe) / γ-Al2O3 catalytic ozone degradation TC reaction system, hydroxyl radicals and superoxide radicals are the key active substances in the catalyst's ozone generation and play a crucial role in the TC degradation reaction.

[0085] Fe-MOFs / supported composite catalysts were added to wastewater containing tetracycline antibiotics. Ozone was introduced into the wastewater in the form of microbubbles using microbubble technology. The Fe-MOFs / supported composite catalysts catalyzed the degradation of the tetracycline antibiotics in the microbubble ozone system at room temperature. Specifically, wastewater containing antibiotics (tetracycline, TC) is injected into a 12L reaction vessel at a concentration of 40 mg / L. Fe-MOFs / carrier composite catalysts are added at dosages of 80 g, 90 g, 100 g, and 110 g, respectively. Ozone is generated using an ozone generator and then enters a gas-liquid mixing pump at an inlet concentration of 6 mg / L. Under a working pressure of 2.5 MPa, the ozone and circulating liquid are efficiently dissolved in a mixing tank. The thoroughly mixed ozone-saturated solution is released through a microporous aeration head, generating a uniform microbubble cluster, significantly increasing the gas-liquid contact surface area. The circulating liquid, containing tetracycline-containing antibiotic wastewater, is connected to the mixing tank via a return pipeline, forming a closed-loop circulation system for degradation.

[0086] This invention utilizes a dissolved-gas-release microbubble generator to dissolve ozone in water under a certain pressure, forming a supersaturated solution. The pressure is then reduced, causing the gas to be released in the form of microbubbles. After introducing microbubble technology into the MIL-101(Fe) / γ-Al2O3 composite material catalytic ozone oxidation system, the TC degradation efficiency increased, proving that microbubbles can enhance ozone production. The principle of TC degradation by the MIL-101(Fe) / γ-Al2O3 catalytic microbubble ozone system is as follows: In the dissolved-gas stage, a high-pressure environment forces a large amount of ozone molecules to dissolve in the water, forming a supersaturated solution; during the release process, the sudden pressure drop causes the supersaturated ozone to be released uniformly in the form of micron-sized bubbles. Its high specific surface area effectively reduces gas-liquid mass transfer resistance, accelerates ozone diffusion into the liquid phase, and ensures uniform concentration distribution within the reaction system. The local high temperature and high pressure environment generated when microbubbles burst further activates the active sites on the surface of MIL-101(Fe) / γ-Al2O3, enhancing its ability to catalyze the decomposition of ozone. At the same time, the local flow field changes induced by microbubbles accelerate the renewal of the liquid film on the catalyst surface, reduce mass transfer resistance, and significantly improve the mass transfer efficiency between pollutants, ozone and catalyst, thereby achieving efficient degradation of pollutants.

[0087] Figure 17 This diagram illustrates the effect of different dosages of ozone on TC degradation in the microbubble ozone system according to the present invention. Figure 17 In the diagram, (a) shows the effect of catalyst dosage on TC degradation, and (b) shows the pseudo-first-order kinetics. Figure 17 As shown in (a), the removal rate of TC increases with increasing catalyst dosage. The degradation efficiencies of TC at catalyst dosages of 80g, 90g, 100g, and 110g are 74.37%, 82.93%, 93.73%, and 94.58%, respectively. The degradation efficiency increased by 19.41% within 50 min. Between 80g and 100g, the adsorption efficiency also increases with increasing catalyst dosage, possibly due to increased porosity enhancing adsorption. With increased catalyst, microbubble ozone can react with the active sites on the catalyst surface. Because the microbubble ozone is uniformly and densely distributed in the liquid, it can increase the reaction with the catalyst to generate more free radicals, which is beneficial for pollutant degradation. Figure 17 As shown in (b), the kinetic constants for the four catalyst dosages are 0.06759 min. -1 0.08251min -1 0.01391min -1 and 0.014715min -1 It can be seen that when the catalyst is added to 110g, the degradation efficiency is not much different from that when it is added to 100g, and the corresponding kinetic constant increases by only 0.0008 min. -1When the TC concentration is 40 mg / L, 100 g of catalyst has reached saturation for the degradation of pollutants. The amount of ozone in the reaction system is limited, and too much catalyst will reduce the catalytic efficiency of ozone. Therefore, 100 g of catalyst is the optimal dosage for the MIL-101(Fe) / γ-Al2O3 composite material catalytic microbubble ozone reaction system.

[0088] Figure 18 This diagram illustrates the effect of ozone concentration on TC degradation in a microbubble ozone system, as presented in this invention. Figure 18 In the diagram, (a) shows the effect of ozone concentration on TC degradation, and (b) shows a pseudo-first-order kinetic diagram. Figure 18 As shown in Figure (a), when the ozone concentration was adjusted to 4 mg / min, 6 mg / min, and 8 mg / min, the degradation efficiencies for TC were 86.38%, 93.73%, and 93.94%, respectively; Figure 18 As shown in (b), the kinetic constant for the reaction at the three ozone concentrations is 0.09536 min. -1 0.1391min -1 and 0.13174min -1 At an ozone concentration of 4 mg / min, the contact between ozone molecules and pollutants in the microbubble ozone reaction is limited, resulting in a slow reaction rate and low degradation efficiency. Furthermore, the amount of reactive oxygen species generated by the MIL-101(Fe) / γ-Al2O3 catalytic microbubble ozone decomposition is limited, making complete degradation of pollutants difficult. However, the improvement at ozone concentrations of 6 mg / min and 8 mg / min is not significant; excessive ozone does not further enhance catalytic efficiency but instead causes some ozone to escape from the system without participating in the reaction, resulting in resource waste. Therefore, an ozone concentration of 6 mg / min was determined to achieve a balance between ozone utilization efficiency and degradation effect, ensuring a high reaction rate while avoiding excessive ozone consumption.

[0089] Figure 19 This is a graph showing the degradation efficiency of the present invention in a microbubble ozone system at different initial TC concentrations. Figure 19 In the diagram, (a) shows the degradation of TC at its initial concentration, and (b) shows the pseudo-first-order kinetics. Figure 19 As shown in Figure (a), the degradation efficiencies were 91.9%, 95.2%, 93.74%, and 83.63% when the initial TC concentration increased from 10 mg / L to 60 mg / L, respectively; Figure 19 As shown in (b), the corresponding reaction kinetic constant is 0.12883 min. -1 0.17096min -1 0.1391min -1 and 0.09526min -1It can be seen that the degradation efficiency decreases with increasing initial TC concentration. When the initial TC concentration is 10 mg / L, 20 mg / L, and 40 mg / L, complete degradation can be achieved within 20 minutes. This is because microbubble ozone molecules have more opportunities to contact pollutants, resulting in a faster reaction rate and higher degradation efficiency. At lower pollutant concentrations, the reactive oxygen species generated from ozone decomposition can fully react with TC molecules, and the degradation process can usually be completed in a very short time. Degradation is almost complete within 10 minutes after introducing ozone microbubbles, but sampling and measurement are difficult during the experiment. Increasing the initial TC concentration to 60 mg / L allows more TC molecules to contact ozone. However, the limited ozone concentration during the reaction reduces the contact probability between ozone molecules and pollutants, slowing the reaction rate and decreasing the degradation efficiency. The reactive oxygen species generated from ozone decomposition may not be sufficient to completely degrade all TC molecules, leading to incomplete degradation. High TC concentrations may compete for ozone and reactive oxygen species, further reducing reaction efficiency. Complete degradation requires increasing the ozone dosage or extending the reaction time to improve the degradation effect.

[0090] Figure 20 This is a graph showing the degradation efficiency of the present invention in a microbubble ozone system at different pH values. Figure 20 In the diagram, (a) shows the effect of pH on TC degradation, and (b) is a pseudo-first-order kinetic diagram. Figure 20 As shown in (a), the higher the pH value, the higher the degradation efficiency of TC by MIL-101(Fe) / γ-Al2O3 catalyzed microbubble ozone. The degradation effect is poor at pH=3, with only 46.85% degradation within 50 minutes. With increasing pH, the TC degradation efficiency increases under neutral and alkaline conditions, which is beneficial for the degradation of TC by MIL-101(Fe) / γ-Al2O3. At pH=6, the TC degradation reaches 93.74%. The adsorption efficiency increases at pH=9 and 12, reaching 94.21% and 94.57% respectively, showing a slight increase in degradation efficiency. Figure 20 As shown in (b), the kinetic constants at pH = 3, 6, 9 and 12 are 0.03015 min. -1 0.1391min -1 0.14512min -1 and 0.14123min -1 In summary, the MIL-101(Fe) / γ-Al2O3 catalytic microbubble ozone degradation TC reaction system is suitable for neutral and alkaline environments.

[0091] Figure 21 This is a stability diagram of the present invention in a microbubble ozone system. (See diagram for example.) Figure 21As shown, during the cycling period, the catalyst activity fluctuated slightly in the initial stage, gradually stabilizing with increasing cycle count. After five cycles, the degradation efficiency of TC by the MIL-101(Fe) / γ-Al2O3 composite material decreased from 93.72% to 85.73%. This slight decrease in TC degradation efficiency may be due to partial wear or blockage of the active sites on the catalyst surface caused by repeated reactions, leading to a reduction in its original catalytic capacity. Overall, the catalyst exhibits good stability within a certain number of cycles, but further optimization is needed to improve its resistance to deactivation during long-term cycling.

[0092] Figure 22 This diagram illustrates the degradation of different tetracycline antibiotics in a microbubble ozone system according to the present invention. Figure 22 In the diagram, (a) is the degradation diagram of chlortetracycline, (b) is the pseudo-first-order kinetic diagram of chlortetracycline degradation, (c) is the degradation diagram of oxytetracycline, (d) is the pseudo-first-order kinetic diagram of oxytetracycline degradation, (e) is the degradation diagram of doxycycline, and (f) is the pseudo-first-order kinetic diagram of doxycycline degradation. Figure 22 The figures show the degradation efficiencies of chlortetracycline, oxytetracycline, and doxycycline under different reaction systems. It can be seen that the MIL-101(Fe) / γ-Al₂O₃ catalyzed microbubble ozone degradation is the most effective reaction system. Furthermore, it demonstrates that microbubble-enhanced ozone technology improves the catalytic reaction and accelerates pollutant degradation. The degradation rates of the three pollutants in the microbubble ozone system were 95.45%, 87.35%, and 85.76%, respectively. Figure 22 As shown in (b), (d), and (e), the first-order kinetic constant is 0.15226 cm⁻¹. -1 0.1030cm -1 and 0.09717cm -1 Degradation experiments on three other tetracycline pollutants showed that MIL-101(Fe) / γ-Al2O3 catalyzed microbubble ozone also has a degradation effect on other pollutants.

[0093] Figure 23 This diagram illustrates the degradation of mixed antibiotics in a microbubble ozone system according to the present invention. Figure 23 In the table, (a) represents the COD removal rate, and (b) represents the TOC removal rate. Figure 23As shown, under conditions where only microbubble ozone is introduced, the catalytic degradation of mixed antibiotic wastewater resulted in a COD (chemical oxygen demand) removal rate of only 52.17% and a TOC (total organic carbon) removal rate of 47.13%. However, with the addition of the MIL-101(Fe) / γ-Al2O3 composite material, under the same conditions, the catalyst-catalyzed microbubble ozone degradation of mixed antibiotic wastewater achieved a COD removal rate of 81.63% and a TOC removal rate of 70.68%. In conclusion, the MIL-101(Fe) / γ-Al2O3 catalytic microbubble ozone system also demonstrates good removal efficiency for mixed antibiotic wastewater, and is of significant importance from the perspective of practical catalyst applications.

[0094] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0095] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a Fe-MOFs / supported composite catalyst, characterized in that, Includes the following steps: Acid-activated spherical γ-Al2O3 and terephthalic acid solution were mixed and subjected to a first solvothermal reaction to chemically anchor terephthalic acid on the surface of spherical γ-Al2O3, resulting in γ-Al2O3 loaded with H2BDC. Soluble iron salts and γ-Al₂O₃ loaded with H₂BDC are dissolved in a solvent, and a second solvothermal reaction is carried out to allow Fe to undergo a reaction. 3+ By coordinating with H2BDC, MIL-101(Fe) crystals were epitaxially grown on the surface of γ-Al2O3 to obtain Fe-MOFs / supported composite catalysts.

2. The method for preparing the Fe-MOFs / supported composite catalyst according to claim 1, characterized in that, The molar ratio of terephthalic acid to acid-activated spherical γ-Al2O3 in the terephthalic acid solution is 2 mmol to 8 mmol: 5 g to 30 g. The terephthalic acid solution is an N,N-dimethylformamide solution of terephthalic acid.

3. The method for preparing the Fe-MOFs / supported composite catalyst according to claim 1, characterized in that, Terephthalic acid solution contains terephthalic acid and Fe in soluble iron salts. 3+ The molar ratio is 1-4:2-8, and the solvent is N,N-dimethylformamide.

4. The method for preparing the Fe-MOFs / supported composite catalyst according to claim 1, characterized in that, The temperature of the first solvothermal reaction is 100℃~120℃, and the time is 18h~22h.

5. The method for preparing the Fe-MOFs / supported composite catalyst according to claim 1, characterized in that, The temperature of the second solvothermal reaction was 100℃~120℃, and the time was 18h~22h.

6. The method for preparing the Fe-MOFs / supported composite catalyst according to claim 1, characterized in that, The specific method for acid activation of spherical γ-Al2O3 is as follows: spherical γ-Al2O3 is immersed in hydrochloric acid solution and acid activated at 65℃~75℃ for 2h~4h, with the mass concentration of hydrochloric acid solution being 36%~38%.

7. A Fe-MOFs / supported composite catalyst, characterized in that, It is prepared using the preparation method according to any one of claims 1 to 6.

8. The application of the Fe-MOFs / supported composite catalyst of claim 7 in the catalytic ozone degradation of antibiotic-containing wastewater.

9. The application according to claim 8, characterized in that, The process includes the following steps: adding Fe-MOFs / supported composite catalyst into wastewater containing tetracycline antibiotics; using microbubble technology to introduce ozone into the wastewater in the form of microbubbles; and degrading the wastewater by the microbubble ozone system catalyzed by the Fe-MOFs / supported composite catalyst at room temperature.

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