Ozone oxidation catalyst for wastewater treatment and preparation and use methods thereof

Abstract

The invention discloses an ozone oxidation catalyst for wastewater treatment as well as a preparation method and a use method thereof, and belongs to the technical field of environmental functional materials and water pollution control. The catalyst comprises a carrier with a three-dimensional ordered mesoporous structure and an active component loaded on the carrier, the active component comprises an atomically dispersed main active metal and a spinel-type auxiliary active metal oxide in the form of nanoclusters, which are spatially adjacently distributed to synergistically catalyze ozone to generate free radicals to degrade pollutants. The preparation method mainly comprises the following steps: preparing the carrier by a template method, anchoring and loading the main active metal in a dual-solvent dipping combined atmosphere, performing in-situ hydrothermal synthesis on the nano-cluster, depositing the heteroatom-doped carbon protective layer and the like. The catalyst has the advantages of high activity, high stability, excellent mass transfer performance, wide pH adaptability, easiness in magnetic separation and recovery and the like, and is suitable for treating industrial wastewater containing refractory organic matters.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials and water pollution control technology, specifically relating to an ozone oxidation catalyst for wastewater treatment and its preparation and application methods. Background Technology

[0002] With rapid industrial development, large quantities of industrial wastewater containing high concentrations of highly toxic and recalcitrant organic pollutants (such as antibiotics, endocrine disruptors, and dyes) are discharged, posing a serious threat to water environment safety and human health. Ozone advanced oxidation technology, due to its strong oxidizing power and lack of secondary pollution, has shown great potential in the deep treatment of recalcitrant wastewater. However, direct oxidation of pollutants by ozone molecules has inherent drawbacks such as high selectivity, low utilization rate, and high operating costs. To overcome these limitations, catalysts are typically used to activate ozone, decomposing it to generate more potent and non-selective hydroxyl radicals (·OH), thereby achieving efficient degradation of pollutants.

[0003] Currently, materials used for ozone catalysis mainly include homogeneous catalysts and heterogeneous catalysts. Homogeneous catalysts (such as Fe) 2+ Co 2+ While some catalysts (such as [specific catalysts]) exhibit high activity, their large-scale application is limited by problems such as difficulty in recovery, potential for secondary pollution, and the need for operation under acidic conditions. Therefore, researching and developing efficient and stable heterogeneous ozone oxidation catalysts has become the current mainstream research direction.

[0004] Existing heterogeneous ozone oxidation catalysts mainly include metal oxides (such as MnO2, CeO2, Fe3O4), supported metal catalysts, and carbon-based materials. Despite some progress, these catalysts still face the following key technological bottlenecks: Balancing catalytic activity and stability is challenging: Traditional supported catalysts often contain active components in the form of nanoparticles or aggregates, resulting in low utilization of active sites. In complex wastewater systems, active components are prone to leaching or surface blockage by intermediate products, leading to a rapid decline in catalytic performance and a short lifespan.

[0005] Mass transfer efficiency limitations: Catalytic reactions involve the contact between ozone, pollutants, and catalyst active sites. Many catalysts, despite having high specific surface areas, have disordered or blocked pore structures, which restricts the diffusion and mass transfer of reactants and products, resulting in the ineffective utilization of internal active sites and limiting the overall reaction rate.

[0006] Single reaction pathway and poor pH adaptability: Most catalysts rely on a single active site or free radical generation pathway, resulting in significant differences in degradation effects on pollutants with different properties. Especially under neutral or alkaline conditions, catalytic activity usually decreases significantly, making it difficult to adapt to the fluctuating pH environment of actual wastewater.

[0007] Catalyst separation and recovery are challenging: Although powdered catalysts have a large specific surface area, solid-liquid separation is difficult in water treatment applications. They are easily lost with the water flow, increasing operating costs and potentially posing environmental risks. While magnetic separation is an effective solution, introducing magnetic components without sacrificing or even enhancing catalytic activity presents a design challenge.

[0008] To address these challenges, researchers have attempted to combine multiple metals or design porous materials, but these efforts often remain at the level of simple physical mixing. They have failed to achieve precise design of active sites at the atomic scale and structural optimization at the mesoscale, resulting in limited synergistic effects and bottlenecks in performance improvement. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an ozone oxidation catalyst for wastewater treatment with high activity, high stability, excellent mass transfer performance and wide pH adaptability, as well as its preparation and use method.

[0010] The technical solution adopted by the present invention to solve its technical problem is: an ozone oxidation catalyst for wastewater treatment, characterized in that it includes a support having a three-dimensional ordered mesoporous structure and an active component loaded on the support; the active component includes an atomically dispersed main active metal and an auxiliary active metal oxide in the form of nanoclusters; the atomically dispersed main active metal and the nanoclusters are spatially adjacent to each other to synergistically catalyze the generation of free radicals from ozone to degrade organic pollutants in water.

[0011] This invention creatively integrates atomically dispersed primary active metals and auxiliary active metal oxides in the form of nanoclusters within a three-dimensional ordered mesoporous carrier. This structure achieves efficient ozone activation through atomically dispersed sites, generating primary superoxide radicals (·O2). - The nanoclusters rapidly convert ozone into more potent hydroxyl radicals (·OH) using adjacent nanocluster sites, forming a highly efficient "radical cascade" reaction pathway. This synergistic design with multiple spatially adjacent active sites significantly improves ozone utilization efficiency and pollutant degradation rates, overcoming the bottleneck of single-active-site catalysts' limited reaction pathways and low efficiency. Simultaneously, atomic-level dispersion greatly enhances the atomic utilization of precious or rare metals, reducing costs.

[0012] Preferably, the carrier of the three-dimensional ordered mesoporous structure is an inorganic oxide carrier, a carbon material carrier, or a composite material of both; the inorganic oxide carrier is alumina, silicon oxide, titanium oxide, or molecular sieve; the carbon material carrier is activated carbon, graphene, carbon nanotubes, or biochar.

[0013] Employing a three-dimensional ordered mesoporous structure as a support, its interconnected and regular channels provide high-speed pathways for the diffusion of reactants (ozone, pollutants) and products, significantly reducing mass transfer resistance and ensuring full utilization of internal active sites. The diverse selection of inorganic oxide and carbon material supports provides optimization space for catalysts in different application scenarios. Inorganic oxide supports such as alumina and molecular sieves possess excellent mechanical strength, thermal stability, and abundant surface hydroxyl groups, facilitating the firm anchoring of active components; titanium oxide also exhibits potential photocatalytic synergistic effects. Carbon material supports such as graphene and carbon nanotubes possess excellent conductivity, accelerating electron transfer in the reaction; activated carbon and biochar are inexpensive and have strong adsorption properties. This composite support allows the catalyst to utilize both the stability of the inorganic phase and the conductivity and adsorption characteristics of carbon materials.

[0014] More preferably, the support is an alumina / nitrogen-doped carbon composite material. Choosing an alumina / nitrogen-doped carbon composite material has two advantages: firstly, the high stability and abundant surface hydroxyl groups of alumina facilitate the anchoring of active components; secondly, the nitrogen-doped carbon layer enhances the electronic conductivity of the support, promoting rapid interfacial electron transfer during catalysis, thereby further improving catalytic efficiency. This composite support combines structural stability and functional synergy.

[0015] Preferably, the pore size range of the three-dimensional ordered mesoporous structure is 2nm~50nm, more preferably 10~30nm, and even more preferably 15±2nm; the specific surface area of ​​the carrier is greater than 300m². 2 / g, preferably greater than 400m 2 / g. The pore size of the three-dimensionally ordered mesoporous structure is precisely controlled, resulting in a specific surface area greater than 300 m² / g. The suitable pore size provides a "highway" for the rapid diffusion of large molecular organic pollutants (such as antibiotics and dyes) in wastewater, greatly reducing mass transfer limitations. Simultaneously, the ultra-high specific surface area ensures that the support can load a sufficiently high density of atomically dispersed active sites, providing abundant reaction interfaces for the catalytic reaction. This combination of "high-flux" pores and "high-density" active surfaces optimizes both mass transfer and reaction kinetics, resulting in a significant improvement in the catalyst's volumetric reaction efficiency.

[0016] Preferably, the atomically dispersed main active metal is selected from one or more of platinum, palladium, gold, iron, cobalt, nickel, copper, manganese, and cerium. Depending on the target pollutants with different characteristics (such as recalcitrant halogenated compounds or common aromatic hydrocarbons) and cost control requirements, efficient but expensive precious metals or economical and practical combinations of non-precious metals can be flexibly selected. This broad range of element selection ensures that the catalyst can achieve an optimal balance between catalytic activity, stability, and manufacturing cost while maintaining high atom utilization.

[0017] Platinum, palladium, and gold are noble metals, while iron, cobalt, nickel, copper, manganese, and cerium are non-noble metals. More preferably, the atomically dispersed main active metal is a combination of copper and cerium. Cerium, with its unique Ce... 3+ / Ce 4+ The redox cycle efficiently activates ozone molecules to generate primary reactive oxygen species; while copper (Cu) + / Cu 2+ The variable valence property exhibits excellent adsorption and activation capabilities for organic pollutants. The two components work closely together at the atomic scale to construct a highly efficient electron transfer channel, significantly enhancing the generation rate and total amount of free radicals. This makes its catalytic activity comparable to some noble metal catalysts, while substantially reducing raw material costs, demonstrating extremely high cost-effectiveness and industrial application value.

[0018] Preferably, the auxiliary active metal oxide in the form of the nanocluster is a spinel-type metal oxide with the general formula AB₂O₄, wherein the A-site and B-site metals are independently selected from one or more of iron, cobalt, nickel, manganese, copper, zinc, and magnesium. The spinel structure itself possesses excellent crystal stability and abundant oxygen vacancy defects, making it a highly efficient surface reaction platform. Its A and B sites can be flexibly occupied by various metal elements such as iron, cobalt, and nickel. Through precise control of the metal ions at the A and B sites, its electronic structure can be optimized, thereby significantly enhancing its resistance to superoxide radicals (·O₂). - The catalytic efficiency of the conversion to hydroxyl radicals (·OH) is enhanced, and a strong synergy is formed with the main active site, which together broadens the applicable pH range of the reaction and improves the overall stability of the catalyst.

[0019] The auxiliary active metal oxide in the form of nanoclusters is preferably cobalt ferrite, nickel ferrite, manganese ferrite, or iron(III) oxide. These spinel compounds each have their own advantages and exhibit significant synergistic effects with the main active site. Cobalt ferrite and nickel ferrite are known for their excellent peroxidase-like activity, efficiently promoting the generation of hydroxyl radicals; manganese ferrite is structurally stable over a wide pH range; while iron(III) oxide possesses both excellent catalytic activity and inherent strong magnetism, providing convenient magnetic separation and recovery capabilities for the catalyst.

[0020] Preferably, the catalyst further comprises a magnetic component for magnetic separation and recovery of the catalyst; the magnetic component is selected from iron(III) oxide, cobalt ferrite, nickel ferrite, or a composite thereof. Introducing a magnetic component into the catalyst successfully endows the material with convenient magnetic separation and recovery characteristics. This design makes the separation of the powdered catalyst after the reaction extremely simple and efficient; rapid solid-liquid separation can be achieved within tens of seconds simply by applying an external magnetic field, completely solving the industry problems of difficult filtration and easy loss of traditional powdered catalysts. This significantly reduces the cost of catalyst use and operating energy consumption, and effectively prevents the environmental risks that may be caused by the loss of nanomaterials.

[0021] Preferably, the magnetic component exists within the carrier in a core-shell structure, where the core is a magnetic particle and the shell is a silica or carbon layer. This core-shell structure effectively prevents the magnetic core from corroding and dissolving in an acidic aqueous environment, avoids contamination of the active component, and improves catalyst stability. The shell also facilitates subsequent loading of active sites. Its preparation can employ the classic sol-gel method or hydrothermal encapsulation method. Specifically, firstly, superparamagnetic iron oxide nanoparticles are prepared via co-precipitation. Subsequently, in an ethanol-water mixture containing ammonia, tetraethyl orthosilicate is used as the silicon source. Utilizing its slow hydrolysis and condensation properties in the aqueous phase, and by controlling the reaction temperature, stirring rate, and dropping rate, the generated silica is uniformly deposited on the surface of the magnetic particles, forming a dense amorphous silica shell. Finally, after centrifugation, washing, and drying, a core-shell structured magnetic component with a regular structure and controllable shell thickness is obtained. If a carbon shell is to be prepared, it can be achieved by chemical vapor deposition of carbon sources such as acetonitrile and carbonization, or by directly using sugars such as glucose for hydrothermal carbonization, based on the above SiO2 coating.

[0022] Preferably, the catalyst surface is coated with a carbon protective layer doped with one or more heteroatoms selected from nitrogen, sulfur, boron, and phosphorus. The heteroatom-doped carbon layer coating the catalyst surface acts like a multifunctional armor. On the one hand, it serves as a physical barrier, effectively preventing the loss and poisoning of active components during use; on the other hand, the introduction of heteroatoms (such as nitrogen) regulates the electron distribution of the carbon layer, enhances interfacial electron conductivity, and promotes the catalytic reaction rate. During preparation, the aforementioned catalyst precursor is placed in a tube furnace and heated to 600℃~800℃ under an inert atmosphere. Then, a mixed gas containing carbon sources (such as methane and ethylene) and heteroatom sources (such as ammonia, thiophene, trimethylboron, and triphenylphosphine) is introduced, causing it to decompose and deposit on the catalyst surface, forming a uniform doped carbon layer.

[0023] A method for preparing the above-mentioned ozone oxidation catalyst for wastewater treatment, characterized by comprising the following steps: (1) A carrier precursor with a three-dimensional ordered mesoporous structure was prepared by template method; (2) The precursor of the main active metal is loaded onto the carrier precursor by impregnation and anchoring process, and then heat-treated to form an atomically dispersed main active metal; (3) Auxiliary active metal oxide nanoclusters are generated on a support loaded with the atomically dispersed main active metal through an in-situ synthesis process; (4) The obtained material is further processed to obtain the final catalyst.

[0024] This preparation method achieves precise customization of the catalyst's microstructure and functional integration through a sequential process of "template-based structure construction → precise anchoring of single atoms → in-situ growth of nanoclusters → functionalization post-processing." The template method ensures the high regularity of the three-dimensional ordered mesoporous structure of the support, laying the foundation for efficient mass transfer; the unique impregnation-anchoring-heat treatment process is key to achieving atomic-level dispersion of metals, effectively preventing agglomeration; and in-situ hydrothermal synthesis ensures uniform nucleation of nanoclusters within confined pores, forming a close spatial synergy with single-atom sites.

[0025] Preferably, in step (1), the template used in the template method is a soft template or a hard template; the soft template is a block copolymer, and the hard template is a monodisperse silica microsphere, polystyrene microsphere, or their self-assembled array; the preparation process includes injecting the carrier precursor solution into the template pores, gelling, drying, and calcining to remove the template. The soft template method is simple, while the hard template method has extremely high structural regularity. This preferred scheme gives the preparation process a high degree of flexibility and controllability, and can select the most suitable template strategy according to the target pore size and specific surface area requirements.

[0026] Taking the hard template method as an example, the specific steps are as follows: First, monodisperse polystyrene microspheres are self-assembled by centrifugation to form a three-dimensional ordered template. Then, boehmite and block copolymer F127 are dissolved in ethanol to prepare a precursor sol, which is then injected into the gaps of the PS template using vacuum assistance. Next, gelation is carried out at 60℃ for 12 hours, followed by drying at 80℃. Finally, the temperature is programmed to reach 550℃ in a tube furnace at a heating rate of 1℃ / min, and calcined for 4 hours to completely remove the PS and F127 templates, thus obtaining an alumina carrier precursor with a three-dimensional ordered macroporous-mesoporous structure.

[0027] Preferably, the impregnation and anchoring process in step (2) is a dual-solvent impregnation method, and the anchoring process is carried out in an atmosphere of ammonia, hydrogen sulfide, or organic amines; the heat treatment temperature is 200℃~600℃, and the atmosphere is an inert gas, hydrogen, or a mixture thereof. The dual-solvent impregnation method combined with the atmosphere anchoring process is the key to achieving atomic-level dispersion of metals. This method utilizes the capillary action between the hydrophilic pores of the carrier and the aqueous solution of the metal precursor, as well as the confinement of the precursor solution by the volatile solvent, to ensure a highly uniform distribution of the active components on the carrier. Subsequent heat treatment in a specific atmosphere firmly anchors the metal atoms by forming strong chemical bonds, effectively suppressing migration and aggregation during the high-temperature treatment process, and providing a reliable guarantee for obtaining high-density, highly stable single-atom sites.

[0028] The specific steps of the dual-solvent impregnation method are as follows: First, the three-dimensional ordered mesoporous support precursor obtained in step (1) is vacuum dehydrated and activated at 250°C for 2 hours. Then, a measured amount of deionized water slightly less than or equal to its total pore volume is used to dissolve a quantified amount of metal nitrate precursor (such as Cu(NO3)2, Ce(NO3)3) to form an aqueous solution. This aqueous solution is slowly added to the support dispersed in n-hexane under stirring, and the aqueous phase is selectively absorbed into the hydrophilic pores of the support by capillary force. After standing and drying, the sample is placed in a tube furnace and treated with ammonia gas at 200°C for 1 hour for anchoring. More preferably, the heat treatment is: reduction at 450°C for 2 hours in a 5% H2 / Ar atmosphere.

[0029] Preferably, the in-situ synthesis process in step (3) is a hydrothermal or solvothermal method. By controlling the pH, temperature and metal ion concentration of the reaction solution, the auxiliary active metal oxide is crystallized in-situ into nanoclusters within the pores of the support.

[0030] Preferably, the subsequent processing in step (4) includes a chemical vapor deposition process for depositing a heteroatom-doped carbon protective layer on the catalyst surface; and / or includes processes such as mixing with a binder, extrusion, or granulation.

[0031] A method for treating wastewater using the above-mentioned ozone oxidation catalyst involves placing the catalyst in a reactor and contacting it with ozone-containing wastewater to carry out a catalytic oxidation reaction.

[0032] Preferably, the reactor is a fixed-bed reactor, a fluidized-bed reactor, or a suspended stirred reactor; when a suspended stirred reactor is used, the catalyst is rapidly separated and recovered by applying an external magnetic field after the reaction is completed.

[0033] Preferably, the catalytic oxidation reaction can be combined with one or more of the following techniques: ultraviolet light irradiation, ultrasonic irradiation, and hydrogen peroxide addition.

[0034] Preferably, when the catalyst activity decreases, the catalyst is regenerated by electrochemical regeneration, thermal regeneration, or chemical cleaning and regeneration methods.

[0035] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention successfully constructs a highly efficient "radical cascade" reaction pathway by synergistically designing atomically dispersed main active metals and spinel-type nanoclusters as auxiliary active centers in a three-dimensional ordered mesoporous support with spatial proximity, achieving a significant improvement in ozone utilization and pollutant degradation rate. The unique high specific surface area and interconnected pore structure of the support ensure excellent mass transfer efficiency and high-density exposure of active sites. The introduction of magnetic core-shell components and surface heteroatom-doped carbon layers solves the industry problems of difficult catalyst recovery and insufficient stability, respectively, achieving convenient magnetic separation and long-term stable operation. Furthermore, the preparation method, through the organic combination of template method, dual-solvent impregnation anchoring, and in-situ synthesis, achieves precise and controllable construction of the catalyst's microstructure. Ultimately, this invention provides a highly efficient catalyst integrating high catalytic activity, excellent stability, wide pH adaptability, and easy recovery and regeneration, along with its reliable preparation and application methods, with comprehensive performance significantly superior to existing technologies. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments. Embodiment 1 is the basic embodiment, and the conditions in each embodiment that are not explicitly described are the same as those in Embodiment 1. Example 1

[0037] 1. Preparation of carrier precursor A suspension of monodisperse polystyrene microspheres with an average diameter of 200 nm (solid content 10 wt%) was centrifuged (3000 rpm, 10 min) to self-assemble into a three-dimensional ordered template at the bottom of a beaker. 10 g of pseudoboehmite powder and 1.0 g of block copolymer F127 were weighed and dissolved together in 100 mL of anhydrous ethanol, and magnetically stirred for 6 h to form a homogeneous alumina sol. This sol was slowly injected into the gaps of the PS template under a vacuum of -0.09 MPa, ensuring complete filling. The mixture was then placed in a 60 °C oven and allowed to stand for 12 h to complete gelation. The gel product was dried at 80 °C for 24 h. It was then transferred to a tube furnace and calcined at a programmed heating rate of 1 °C / min to 550 °C under air atmosphere for 4 h to completely remove the PS template and F127. After natural cooling, the mixture was ground to obtain a white alumina carrier powder (denoted as 3DOM-Al2O3) with a three-dimensional ordered macroporous-mesoporous structure. According to BET testing, its specific surface area is 420 m². 2 / g, with a most probable pore size of 15nm.

[0038] 2. Introduction of magnetic core-shell components 5.56 g FeCl2·4H2O and 13.52 g FeCl3·6H2O were dissolved in 200 mL of deoxygenated water and stirred vigorously under nitrogen protection in an 80 °C water bath. 20 mL of ammonia water (28 wt%) was quickly added, and after reacting for 1 h, the resulting black Fe3O4 particles were separated by a magnet and washed with deionized water until neutral.

[0039] The above 1.0 g Fe3O4 particles were dispersed in a mixed solution consisting of 160 mL ethanol, 40 mL water, and 4 mL ammonia. After uniform ultrasonic dispersion, 2 mL tetraethyl orthosilicate (TEOS) was slowly added dropwise, and the mixture was stirred at room temperature for 6 h. After the reaction was completed, the particles were magnetically separated, washed, and dried to obtain core-shell structured Fe3O4-SiO2 powder.

[0040] 1.0g of 3DOM-Al2O3 carrier powder and 0.2g of Fe3O4-SiO2 powder were thoroughly ground and mixed in an agate mortar for 30 minutes to obtain a preliminary composite powder.

[0041] 3. Atomic-scale dispersion of Cu and Ce loading The composite powder was vacuum treated at 250°C for 2 hours to obtain activated carrier powder and simultaneously remove surface physically adsorbed water.

[0042] Take 0.8 mL of deionized water, dissolve 0.024 g Cu(NO3)2·3H2O and 0.043 g Ce(NO3)3·6H2O in it to obtain an aqueous solution.

[0043] 1.0 g of activated carrier powder was dispersed in 50 mL of n-hexane to obtain an aqueous suspension.

[0044] Under magnetic stirring, the aqueous solution was added dropwise to the oil suspension, and stirring continued for 2 hours after the addition was complete. After standing for 12 hours, the solution was filtered and dried at 60°C.

[0045] The dried material was placed in a tube furnace, and ammonia gas was first introduced at a rate of 50 mL / min and treated at 200 °C for 1 h. Then, the flow rate was switched to a 5% H2 / Ar mixed gas of 100 mL / min, and the temperature was increased to 450 °C at a rate of 5 °C / min for reduction for 2 h. After furnace cooling, a magnetic support loaded with atomically dispersed Cu and Ce was obtained.

[0046] 4. In-situ synthesis of cobalt ferrite nanoclusters Weigh 0.728g Co(NO3)2·6H2O and 1.616g Fe(NO3)3·9H2O (Co:Fe molar ratio = 1:2), and dissolve them in 40mL of deionized water to prepare a precursor solution.

[0047] The magnetic support loaded with atomically dispersed Cu and Ce obtained in step 3 of 1.0 was added to the above precursor solution and ultrasonically dispersed for 15 min. Then it was transferred to a 100 mL polytetrafluoroethylene-lined high-pressure reactor and subjected to hydrothermal reaction at 120 °C for 6 h.

[0048] After the reaction was completed, the mixture was allowed to cool naturally, and the product was separated using a magnet. It was then washed several times alternately with deionized water and ethanol, and dried at 80°C. This yielded a powder in which cobalt ferrite nanoclusters were formed in situ within the pores of the support.

[0049] 5. Deposition and Formation of Nitrogen-Doped Carbon Protective Layer Chemical vapor deposition: The powder obtained in step 4 was placed in a quartz boat and then placed in a tube furnace. The temperature was increased to 700°C at 5°C / min under an Ar2 atmosphere. Acetonitrile vapor carried by Ar2 bubbles was then introduced at a total flow rate of 100 mL / min, and deposition was carried out at 700°C for 30 min. The acetonitrile vapor was then stopped, and the mixture was cooled to room temperature under Ar protection to obtain the final catalyst powder with a nitrogen-doped carbon layer coated on its surface.

[0050] Molding: The final catalyst powder is mixed with 3wt% boehmite binder, and an appropriate amount of deionized water is added to knead it. The mixture is then extruded into short columnar particles with a diameter of 3mm and a length of 3mm~5mm using an extruder. The particles are dried at 100℃ and then activated in air at 400℃ for 2 hours to obtain the finished catalyst.

[0051] The catalyst particles prepared in this embodiment were loaded into a fixed-bed ozone catalytic reactor to treat simulated pharmaceutical wastewater (containing 20 mg / L ceftriaxone sodium) with an initial COD of 500 mg / L. The reactor was operated continuously under the conditions of ambient temperature, pH=7, ozone dosage of 30 mg / L, and hydraulic retention time of 30 min. The catalyst consistently maintained a degradation rate of ceftriaxone sodium above 99%, and a COD removal rate consistently above 85%. When the catalyst activity slightly decreased after long-term operation, it was regenerated by soaking in 0.05M dilute nitric acid for 2 hours, after which the activity recovered to over 95% of the initial activity. Example 2

[0052] First, using a hard template method, monodisperse silica microspheres (50 nm in diameter) were self-assembled to form a template. An aqueous solution of graphene oxide was injected into the template pores. After freeze-drying, the template was removed by calcination at 800°C for 2 hours under an argon atmosphere, yielding a three-dimensional ordered mesoporous graphene support with a pore size of 50 nm and a specific surface area of ​​520 m². 2 / g.

[0053] Subsequently, a dual-solvent impregnation method was used: the support was dispersed in n-hexane, and an aqueous solution containing chloroplatinic acid (H2PtCl6) (platinum loading of 1.0 wt%) was added. After drying, it was reduced at 600 °C for 2 h under a 5% H2 / Ar atmosphere to form atomically dispersed platinum.

[0054] Next, a hydrothermal method was used: the platinum-supported support was reacted with a solution of nickel nitrate and ferric nitrate (Ni:Fe molar ratio = 1:2) at 150 °C for 12 h to generate nickel ferrite nanoclusters.

[0055] Finally, a sulfur-doped carbon protective layer was deposited by chemical vapor deposition at 650°C with methane and thiophene vapor for 30 minutes, and then extruded with a binder.

[0056] The catalyst achieved a 99% degradation rate of p-chlorophenol in acidic wastewater with pH=4 within 20 minutes, an ozone utilization rate of up to 90%, and a platinum leaching amount of less than 0.01 ppm. Example 3

[0057] Using silica as a carrier, the pore size was designed to be 2 nm. A soft template method was employed: block copolymer P123 was used as a template and gelled with tetraethyl orthosilicate under acidic conditions. After drying at 60 °C and calcining at 550 °C, a pore size of 2 nm and a specific surface area of ​​320 m² were obtained. 2 / g of three-dimensional ordered mesoporous silica.

[0058] Then, using a dual-solvent impregnation method, an aqueous solution of ferric nitrate and cobalt nitrate (Fe:Co molar ratio = 1:1) was injected into the support, anchored at 200℃ for 1 hour under an ammonia atmosphere, and then heat-treated at 400℃ in argon to form atomically dispersed iron-cobalt sites. Since iron(III) oxide possesses both auxiliary activity and magnetism, it was directly converted into iron(III) oxide nanoclusters via an in-situ hydrothermal method at 100℃ through partial oxidation of the iron salt, eliminating the need for the introduction of additional magnetic components.

[0059] In subsequent processing, the carbon protective layer is omitted, and the powder is simply granulated with silica sol binder.

[0060] When treating dye-containing wastewater, the catalyst maintains an 85% COD removal rate under alkaline conditions at pH=10, and the recovery rate exceeds 99% through magnetic separation. Example 4

[0061] An alumina / nitrogen-doped carbon composite material was used as the support. First, three-dimensional ordered mesoporous alumina (pore size 15 nm) was prepared using a hard template method. Then, a nitrogen-doped carbon layer was formed on its surface by chemical vapor deposition at 500 °C with acetonitrile, resulting in a composite support with a specific surface area of ​​480 m². 2 / g.

[0062] Manganese and cerium were loaded using a dual-solvent impregnation method: an aqueous solution of manganese nitrate and cerium nitrate (Mn:Ce molar ratio = 2:1) was impregnated, anchored at 250°C under a triethylamine atmosphere, and then reduced at 450°C in 5% H2 / Ar to form atomically dispersed manganese-cerium sites.

[0063] Subsequently, manganese ferrite nanoclusters were generated via a hydrothermal method at pH 8 and 120℃. Magnetic components were introduced into cobalt ferrite (CoFe2O4): a CoFe2O4-C core-shell structure was prepared by co-precipitation (the carbon shell was formed by hydrothermal carbonization of glucose), and then composited with a support. Finally, a nitrogen-doped carbon protective layer was deposited and extruded.

[0064] The catalyst exhibits a degradation rate of over 95% for bisphenol A across a wide pH range (4-10), with an activity decrease of less than 5% after 50 cycles. Example 5

[0065] Using Y-type molecular sieves as a support, its mesoporous structure was controlled by soft template (CTAB) to obtain a pore size of 30 nm and a specific surface area of ​​410 m². 2 / g of three-dimensional ordered mesoporous molecular sieves.

[0066] Gold is used as the primary active metal: chloroauric acid (HAuCl4) solution is loaded onto a support via a dual-solvent impregnation method, anchored at 300°C under a hydrogen sulfide atmosphere, and then reduced in hydrogen at 400°C to form atomically dispersed gold. Cobalt ferrite is used as the auxiliary metal oxide: nanoclusters are generated by reacting in ethylene glycol solvent at 180°C for 8 hours via a solvothermal method. No additional magnetic components are introduced; separation is achieved using the inherent magnetism of cobalt ferrite.

[0067] In subsequent processing, a boron-doped carbon protective layer was deposited by chemical vapor deposition at 600°C by introducing ethylene and trimethylboron vapor.

[0068] The catalyst achieved a 98% degradation rate of tetracycline-containing wastewater within 30 minutes, with extremely low gold leaching (<0.005ppm). Example 6

[0069] Biochar was used as a carrier. After carbonizing rice husks, pores were created using a rigid template (PS microsphere) method to obtain pores with a diameter of 10 nm and a specific surface area of ​​380 m². 2 / g of three-dimensional ordered mesoporous biochar.

[0070] The main active metals are nickel and copper: nickel nitrate and copper nitrate (Ni:Cu molar ratio = 1:1) are loaded via a dual-solvent impregnation method and directly pyrolyzed and anchored at 600℃ under an ammonia atmosphere to form atomically dispersed sites. The auxiliary metal oxide is zinc ferrite (ZnFe2O4): generated via a hydrothermal method at 100℃ for 6 hours. Magnetic components are omitted.

[0071] In subsequent processing, a phosphorus-doped carbon protective layer (using triphenylphosphine as the phosphorus source) is deposited and granulated.

[0072] When treating dyeing and printing wastewater, the catalyst achieves a stable COD removal rate of over 80%, and the cost is reduced by 30% compared to Example 1. Example 7

[0073] First, a hard template method was used: 200 nm monodisperse polystyrene microspheres were centrifuged and self-assembled into a template. An ethanol sol of boehmite and F127 was then vacuum-infused, followed by gelation at 60 °C and drying at 80 °C. The mixture was then calcined at 550 °C for 4 hours with a temperature program of 1 °C / min, yielding a pore size of 15 ± 2 nm and a specific surface area of ​​420 m². 2 / g of three-dimensional ordered mesoporous alumina support.

[0074] Subsequently, a dual-solvent impregnation process was performed: the support activated under vacuum at 250°C was dispersed in n-hexane, injected into a pore volume aqueous solution containing copper nitrate and cerium nitrate (Cu:Ce molar ratio 1:1), dried, anchored at 200°C for 1 h in an ammonia atmosphere, and then reduced at 450°C for 2 h in 5% H2 / Ar atmosphere, successfully obtaining atomically dispersed Cu-Ce active sites.

[0075] Next, cobalt nitrate and ferric nitrate (Co:Fe=1:2) were crystallized in situ within the pores of the carrier by a hydrothermal method at pH=7 and 120℃ for 6 hours to generate cobalt ferrite nanoclusters.

[0076] Then, a nitrogen-doped carbon protective layer is formed by chemical vapor deposition at 700°C with acetonitrile vapor for 30 minutes.

[0077] Finally, it was mixed with 3 wt% boehmite binder, extruded, and activated at 400°C.

[0078] When treating wastewater containing 20 mg / L norfloxacin (pH=7, ozone 30 mg / L), the catalyst showed a degradation rate of >99.5% in 30 minutes, and its activity decreased by <3% after 10 cycles. Example 8

[0079] A soft template method was used: using block copolymer P123 as a template, and tetraethyl orthosilicate and sucrose as precursors, evaporation-induced self-assembly and carbonization at 850℃ in an inert atmosphere were employed to prepare a silica / carbon composite carrier with a specific surface area as high as 650 m². 2 / g, with pore size distribution ranging from 5 to 10 nm.

[0080] Subsequently, non-precious metal manganese-cerium was loaded using a dual-solvent impregnation method: anchoring was performed in a triethylamine atmosphere at 250°C, followed by heat treatment in argon at 500°C to form atomically dispersed sites. The auxiliary component, manganese ferrite nanoclusters, was synthesized via a hydrothermal method (140°C, 8 h) to enhance stability under acidic conditions (pH=3).

[0081] A sulfur-doped carbon layer (using thiophene as the sulfur source) is deposited on the catalyst surface via CVD.

[0082] When treating acidic dye wastewater (pH=3), the decolorization rate of azo dyes reached 99% within 15 minutes with ozone addition. Example 9

[0083] Titanium oxide (P25) was selected as the carrier, and its three-dimensional ordered mesoporous structure with a pore size of about 8 nm was replicated by the nano-casting hard template method (using SBA-15 as the template).

[0084] The atomically dispersed main active metal is cerium, supported by a dual-solvent impregnation combined with ammonia anchoring (300℃) process. The auxiliary active component is in-situ hydrothermally generated copper ferrite nanoclusters. The titanium oxide support generates photogenerated electrons under ultraviolet irradiation, producing a synergistic effect with the ozone catalysis process. The catalyst is used in conjunction with ultraviolet irradiation (wavelength 254 nm).

[0085] When treating phenol wastewater over a wide pH range from 5 to 9, the catalyst-UV-ozone triple system maintained a TOC removal rate of over 85%, which is significantly higher than ozone catalysis or photocatalysis alone. Example 10

[0086] First, the core-shell structured magnetic components were prepared: Fe3O4-SiO2 nanospheres were prepared using a co-precipitation method, and then precisely coated with a 30 nm thick silica shell using the Stöber method. These magnetic microspheres were then mixed with alumina sol and, using the template method described above, fabricated a composite support in which the magnetic components were uniformly distributed within the support. The atomically dispersed active metal was nickel, and the auxiliary component was nickel-ferrite nanoclusters. The catalyst was ultimately shaped into spherical particles with a diameter of 2–3 mm for use in fixed-bed reactors.

[0087] In an accelerated life test lasting 100 hours, the catalyst bed pressure drop remained stable while treating simulated petrochemical wastewater, and the COD removal rate was maintained above 75%. After the reaction, the catalyst was removed from the reactor, and complete solid-liquid separation was achieved within 30 seconds under a magnetic field strength of 0.5T.

[0088] Comparative Example 1 The same three-dimensional ordered mesoporous alumina support as in Example 1 was used, but the active components were loaded using the traditional impregnation method. Copper nitrate, cerium nitrate, cobalt nitrate, and iron nitrate (the total molar amount of metals was the same as in Example 1, and the Cu:Ce:Co:Fe molar ratio was the same as in Example 1) were dissolved together in deionized water and loaded onto the support using an equal-volume impregnation method. The mixture was then directly calcined in air at the same temperature (450°C) for 3 hours.

[0089] This method results in the active components existing on the carrier surface in the form of larger-sized mixed metal oxide nanoparticles or aggregates, rather than atomically dispersed and well-ordered nanoclusters.

[0090] The comparative catalyst initially achieved a degradation rate of approximately 85% for ceftriaxone sodium, but after 10 consecutive cycles, the degradation rate rapidly decreased to approximately 60%. Significant aggregation and leaching of the active component occurred, and its catalytic activity and stability were far lower than those of the present invention.

[0091] Comparative Example 2 This comparative example uses mesoporous alumina (with a wide pore size distribution of 2-50 nm and disordered pore channels) as a carrier, with a specific surface area of ​​approximately 300 m². 2 / g. The types, loading order, and processes of the active components are exactly the same as in Example 1, that is, atomically dispersed Cu-Ce is loaded first, and then cobalt ferrite nanoclusters are generated in situ.

[0092] Performance tests were conducted in the same fixed-bed reactor as in Example 1. The results showed that, under the same operating conditions, the comparative catalyst could only achieve a maximum degradation rate of 70% for ceftriaxone sodium, and required a longer hydraulic retention time (50 min) to achieve a similar effect to Example 1.

[0093] The catalysts prepared in all examples and comparative examples were tested for performance under the same conditions. The test method is as follows: 1.0 g of catalyst (comparative examples are powder, and all examples in this invention are shaped granules unless otherwise specified) was weighed and used to treat 500 mL of simulated wastewater with an initial COD of 500 mg / L and containing 20 mg / L ceftriaxone sodium. Catalytic ozone oxidation experiments were conducted at room temperature, initial pH=7, ozone dosage of 30 mg / L, and reaction time of 30 min. Catalyst recovery was achieved by applying an external magnetic field of 0.3 T (centrifugation was used for non-magnetic samples), and stability was evaluated through repeated use tests. Specific performance comparison data are shown in Table 1 below.

[0094] Table 1. Catalyst performance parameters of the examples and comparative examples Ceftriaxone sodium degradation rate (%) COD removal rate (%) Activity retention rate after 10 cycles, % Magnetic separation efficiency (%) Example 1 99.5 85 97.8 >99.5 Example 2 99.8 88 98.3 >99.5 Example 3 98.5 83 95.2 >99 Example 4 99.2 86 96.1 >99.5 Example 5 99.7 87 96.7 >98 Example 6 96.0 78 90.4 not applicable Example 7 99.5 86 97.2 >99.5 Example 8 99.3 87 94.3 >99 Example 9 99.1 (no UV) 99.5 (with UV) 85 (initial) 89 (after 10 times) 92.8 >98 Example 10 99.0 (initial) > 75 (after 100 hours) 82 (initial) 75 (after 100 hours) 94.4 >99.5 Comparative Example 1 85 (initial) 60 (after 10 times) 70 (initial) 45 (after 10 times) 60 >99 (centrifuged) Comparative Example 2 70 60 85 >99 (centrifuged) The embodiments of this invention exhibit significantly superior performance: all embodiments (1-10) show a degradation rate of ceftriaxone sodium exceeding 96%, a COD removal rate exceeding 78%, and an activity retention rate exceeding 90% after 10 cycles, far superior to the comparative example. Compared to comparative example 1, the atomically dispersed and nanocluster-synergistic structure of this invention demonstrates an overwhelming advantage in initial activity and stability. Compared to comparative example 2, the excellent mass transfer efficiency resulting from the three-dimensional ordered mesoporous structure of this invention is the foundation for achieving high degradation rates.

[0095] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An ozone oxidation catalyst for wastewater treatment, characterized in that, The invention includes a carrier having a three-dimensional ordered mesoporous structure and an active component loaded on the carrier; the active component includes an atomically dispersed main active metal and an auxiliary active metal oxide in the form of nanoclusters; the atomically dispersed main active metal and the nanoclusters are spatially adjacent to each other.

2. The ozone oxidation catalyst for wastewater treatment according to claim 1, characterized in that: The carrier of the three-dimensional ordered mesoporous structure is an inorganic oxide carrier, a carbon material carrier, or a composite material of both; the inorganic oxide carrier is alumina, silicon oxide, titanium oxide, or molecular sieve; the carbon material carrier is activated carbon, graphene, carbon nanotubes, or biochar.

3. The ozone oxidation catalyst for wastewater treatment according to claim 1 or 2, characterized in that: The pore size range of the three-dimensional ordered mesoporous structure is 2nm~50nm; the specific surface area of ​​the carrier is greater than 300m². 2 / g.

4. The ozone oxidation catalyst for wastewater treatment according to claim 1, characterized in that: The atomically dispersed main active metal is selected from one or more of platinum, palladium, gold, iron, cobalt, nickel, copper, manganese, and cerium.

5. The ozone oxidation catalyst for wastewater treatment according to claim 1, characterized in that: The auxiliary active metal oxide in the form of nanoclusters is a spinel-type metal oxide with the general formula AB2O4, wherein the metals at the A-site and B-site are independently selected from one or more of iron, cobalt, nickel, manganese, copper, zinc, and magnesium.

6. The ozone oxidation catalyst for wastewater treatment according to claim 1, characterized in that: The catalyst further comprises a magnetic component; the magnetic component is selected from iron oxide, cobalt ferrite, nickel ferrite or their complexes; the magnetic component exists in the support in the form of a core-shell structure, wherein the core is a magnetic particle and the shell is silicon dioxide or a carbon layer.

7. The ozone oxidation catalyst for wastewater treatment according to claim 1, characterized in that: The catalyst surface is coated with a carbon protective layer doped with one or more heteroatoms from nitrogen, sulfur, boron, and phosphorus.

8. A method for preparing an ozone oxidation catalyst for wastewater treatment as described in any one of claims 1 to 7, characterized in that, Includes the following steps: (1) A carrier precursor with a three-dimensional ordered mesoporous structure was prepared by template method; (2) The precursor of the main active metal is loaded onto the carrier precursor by impregnation and anchoring process, and then heat-treated to form an atomically dispersed main active metal; (3) Auxiliary active metal oxide nanoclusters are generated on a support loaded with the atomically dispersed main active metal through an in-situ synthesis process; (4) The obtained material is further processed to obtain the final catalyst.

9. The method for preparing an ozone oxidation catalyst for wastewater treatment according to claim 8, characterized in that, In step (1), the template used in the template method is a soft template or a hard template; the soft template is a block copolymer, and the hard template is a monodisperse silica microsphere, polystyrene microsphere or their self-assembled array; the preparation process includes injecting the carrier precursor solution into the template pores, gelling, drying and calcining to remove the template.

10. The method for preparing an ozone oxidation catalyst for wastewater treatment according to claim 8, characterized in that, The impregnation and anchoring process in step (2) is a dual-solvent impregnation method, and the anchoring process is carried out in an atmosphere of ammonia, hydrogen sulfide or organic amine; the temperature of the heat treatment is 200℃~600℃, and the atmosphere is an inert gas, hydrogen or a mixture thereof.