Nanocluster, monatomic self-driving Fenton-like system composite catalyst and application

Abstract

The invention discloses a nanocluster, a monatomic self-driving Fenton-like system composite catalyst and application, and particularly relates to the technical field of wastewater treatment. According to the system, platinum group metal nanoclusters and transition metal monatomic active centers are synchronously constructed on a porous carbon-based carrier, the nanoclusters are used for efficiently catalyzing reduction of dissolved oxygen two electrons to generate hydrogen peroxide in situ, and hydrogen peroxide is rapidly activated by means of adjacent monatomic sites to generate hydroxyl radicals, so that complete self-driven catalytic circulation is formed. The catalyst realizes accurate regulation and stable anchoring of active sites through carrier heteroatom modification, ligand complexation and programmed gradient pyrolysis processes, shows broad-spectrum degradation capacity on organic pollutants such as antibiotics, dyes and phenols under a near-neutral condition, has the advantages of wide pH application range, low metal dissolution amount and good stability, and can be widely applied to the field of biodegradation of organic pollutants such as antibiotics, dyes, phenols and the like. And an efficient and green technical scheme is provided for organic wastewater degradation treatment.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and to a nano-cluster, single-atom self-driven Fenton-like composite catalyst and its application. Background Technology

[0002] Traditional Fenton reaction system ( It can generate strong oxidizing hydroxyl radicals ( This system effectively degrades difficult-to-treat organic wastewater and is therefore widely used in wastewater treatment. However, this system has several inherent drawbacks: the reaction system has a narrow pH range (usually needs to be maintained at 3-4), a large amount of iron-containing sludge is generated during the reaction, which can easily cause secondary pollution, and continuous addition of hydrogen peroxide is required. Oxidants such as oxidants lead to high operating costs and pose safety hazards during storage and transportation, thus limiting their large-scale promotion in practical engineering.

[0003] To overcome the limitations of the traditional Fenton system, Fenton-like technologies have emerged. These technologies utilize other transition metal ions for homogeneous catalysis or employ transition metal oxides to construct heterogeneous catalytic systems, thus replacing homogeneous catalysis. This type of technology broadens the applicable pH range of the reaction to some extent and reduces sludge production. Nevertheless, existing Fenton-like catalysts still face the following key bottlenecks in practical applications: First, the reaction driving force is highly dependent on external energy input or the continuous addition of large amounts of chemical oxidants, resulting in high equipment investment and operating energy consumption, and potential risks associated with the transportation and storage of oxidants; Second, the transition metal-based active components in the catalyst are prone to aggregation, leading to a decrease in the active surface area, prolonged electron transport paths between active sites, and reduced efficiency; Third, metal ion dissolution is significant, with iron ion dissolution concentrations often exceeding 1 mg / L in traditional homogeneous Fenton-like systems. While heterogeneous catalysts inhibit dissolution to some extent, they still cannot fully meet stringent emission standards, posing secondary water pollution and ecological risks; Fourth, the reaction system suffers from insufficient mass transfer efficiency, inadequate contact between the catalyst and pollutant molecules, and high interfacial mass transfer resistance, resulting in limited degradation rates and prolonged treatment cycles.

[0004] To address the aforementioned technical shortcomings, existing research has disclosed several improvement schemes. For example, one involves loading pollen onto a carbon support... and Fenton-like catalysts activate oxidants via photocatalysis to produce This process degrades organic pollutants in water. Another report describes a transition metal-doped ferrous disulfide catalyst supported on sulfur-doped carbon nanotubes, which enhances structural stability by controlling the size distribution of active particles inside and outside the nanotubes; however, this system still requires continuous addition. As an oxidant, it has not fundamentally escaped its dependence on external chemical reagents. China University of Mining and Technology has developed a self-driven catalyst for the photocatalytic degradation of tetracycline, through... Platinum is introduced onto the surface of the composite material using physical vapor deposition to decompose the added oxidant under photocatalytic conditions and generate bubbles to enhance mass transfer. However, this technology does not involve the in-situ generation process of the oxidant. In summary, existing Fenton-like technologies largely rely on external energy inputs such as light and electricity to improve reaction performance, but have not yet effectively solved the fundamental problems of low catalytic efficiency, complex reaction pathways, and high energy requirements.

[0005] Therefore, it is necessary to develop a self-driven Fenton-like system capable of in-situ generation of oxidants, utilizing inherent pollutants, dissolved oxygen, and even water molecules themselves in water bodies to generate oxidants in situ. The presence of reactive species such as superoxide radicals significantly reduces dependence on external oxidants, demonstrating significant scientific research value and application prospects. The realization of such systems requires catalysts possessing both highly uniform active sites and multi-site synergistic catalytic capabilities. Single-atom catalysts exhibit the highest atom utilization efficiency and well-defined, uniform coordination structures, which are beneficial for the activation of small-molecule reactants. However, their single coordination environment often struggles to complete complex multi-step catalytic processes, and metal loading is generally limited. Nanocluster catalysts, composed of several to dozens of atoms, possess unique electronic structures and a richer array of active sites, enabling efficient promotion of catalytic reactions requiring multi-site synergy. Therefore, this invention aims to comprehensively utilize the synergistic effects of single-atom and nanocluster catalysts to construct a self-driven Fenton-like reaction system capable of efficiently and stably generating oxidants in situ. Summary of the Invention

[0006] To overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a nano-cluster, single-atom self-driven Fenton-like composite catalyst and its application, which solves the problems of narrow pH range of traditional Fenton reactions, secondary pollution caused by the generation of large amounts of iron sludge hazardous waste, and the need for continuous addition of oxidants.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A nanocluster, single-atom self-driven Fenton-like composite catalyst specifically includes the following steps:

[0009] S1: The porous carbon-based support was immersed in sulfuric acid, phosphoric acid and nitric acid solutions and ultrasonically treated. The ultrasonic power was set to 100-500W and the ultrasonic time was 1-2h. Then it was filtered and separated, and washed with deionized water until the filtrate was neutral. Finally, it was dried at 120℃ until the mass was constant to obtain the N, S and P modified carbon-based support.

[0010] S2: Dissolve the transition metal salt and organic ligand in a solvent, then stir until homogeneous to obtain the composite metal precursor impregnation solution;

[0011] S3: The pretreated carrier obtained in S1 is added to the metal precursor solution prepared in S2 to impregnate the load. Then, it is placed at 40-80℃ and heated and stirred for 4-12 hours. After that, it is filtered and separated. Finally, it is dried at 120℃ to constant weight to obtain the pre-impregnated carrier solid.

[0012] S4: Prepare an aqueous solution of platinum group metal salts, and then spray it onto the surface of the pre-impregnated carrier in a double cone rotary impregnator;

[0013] S5: The catalyst precursor obtained in S4 is transferred into a rotary kiln and subjected to high-temperature segmented calcination through a one-pot gradient pyrolysis method under a certain atmosphere protection. Then, the simultaneous construction of single-atom sites and nanoclusters is achieved by controlling the calcination atmosphere, heating program and holding time.

[0014] S6: The catalyst solid obtained in S5 is crushed to above 300 mesh by horizontal ball milling, and then the particles below 300 mesh are separated by high frequency vibrating screen as the finished catalyst. The particles above 300 mesh are crushed by secondary ball milling to the particle size of less than 300 mesh.

[0015] Preferably, the porous carbon-based support in S1 is a carbon-based material with high specific surface area and abundant defects. At the same time, the support is rich in N, S and P, which can serve as anchoring sites for heteroatoms and stabilize single atoms and nanoclusters.

[0016] Preferably, the acid solution in S1 includes one or more of nitric acid, sulfuric acid, and hydrochloric acid, with a concentration of 0.5 to 2 mol / L.

[0017] Preferably, the transition metal in S2 is one or more of the nitrates of Fe, Co, Ni, Cu, Mn, and Ce; the organic ligand is a nitrogen-containing ligand including urea, thiourea, ethylenediaminetetraacetic acid, ethylenediamine, and o-phenanthroline; the sulfur ligand includes thiourea, and the phosphorus-containing ligand includes trimethylphosphine and tricyclohexylphosphine.

[0018] Preferably, the concentration of the transition metal salt in S2 is 0.01–0.1 mol / L; and the molar ratio of the three transition metal salts is 1.5–3:1:1; the molar ratio of the three organic ligands is 1:1:1; the total molar ratio of the transition metal salt to the organic ligands is 1.2:1; and the solvent is deionized water, ethanol, and tert-butanol.

[0019] Preferably, the total mass of transition metal salts in the impregnation solution in S3 accounts for 5 to 12 wt% of the mass of the dry carrier.

[0020] Preferably, the platinum group metal salt in S4 is one of chloroplatinic acid and ruthenium trichloride, wherein the molar ratio of the platinum group metal salt to the transition metal salt in S2 is 1:15-25; the double cone rotary impregnator has a drying function, and a dry catalyst precursor can be directly obtained after spray impregnation.

[0021] Preferably, in S5, the gradient pyrolysis calcination is divided into air atmosphere, nitrogen atmosphere, and hydrogen-nitrogen mixed atmosphere; the air atmosphere is heated to 150-200℃ at a heating rate of 2-5℃ / min and held for 1-2 hours; the nitrogen atmosphere is heated to 400-600℃ at a heating rate of 3-8℃ / min and held for 2-4 hours; the hydrogen-nitrogen mixed atmosphere is heated to 700-900℃ at a heating rate of 2-5℃ / min and held for 1-3 hours.

[0022] Preferably, the air atmosphere, nitrogen atmosphere, and hydrogen-nitrogen atmosphere described in S5 all have a flow rate of 80-200 mL / min.

[0023] Application of a nanocluster, single-atom self-driven Fenton-like composite catalyst

[0024] Preferably, the synergistic effect of nanoclusters and single atoms achieves arrive arrive It has a high efficiency and rapid conversion, and then effectively degrades organic pollutants such as antibiotics and phenols.

[0025] The technical effects and advantages of this invention, which describes a nanocluster, single-atom self-driven Fenton-like composite catalyst and its application, are as follows:

[0026] 1. This invention uses a low amount of oxidant, compared to traditional methods. and The Fenton system reduces hydrogen peroxide usage by 15-36%, significantly lowering operating costs and eliminating safety hazards associated with storing high-concentration hydrogen peroxide.

[0027] 2. This invention is highly efficient and broad-spectrum; the synergistic effect of its nanoclusters and single atoms achieves... arrive Then Its efficient and rapid conversion exhibits excellent degradation capabilities for a variety of organic pollutants, such as antibiotics, dyes, and phenols.

[0028] 3. This invention has a wide pH adaptability. Due to the use of a stable carbon-based supported catalyst, the system can maintain high activity in a near-neutral or even wider pH range, thus solving the acidic bottleneck of traditional Fenton technology.

[0029] 4. This invention is a green and sustainable method. The hydrogen peroxide oxidant produced in situ uses oxygen and water as reactants. The reaction process is clean and has no secondary pollution, which is in line with the principles of green chemistry.

[0030] 5. The catalyst of this invention has good stability. The strong anchoring effect of the support on single atoms and nanoclusters prevents their leaching and aggregation during the reaction process. The catalyst can be recycled multiple times without significant decrease in activity.

[0031] 6. This invention, in situ The formation of [something] is based on the principle of [something] in water bodies. It is efficiently and continuously reduced to form on the electron-rich center of nanoclusters via a two-electron reduction pathway. This nanocluster possesses a unique geometric and electronic structure, thus exhibiting high selectivity and activity for the reaction. The equation for this reaction is as follows: .

[0032] 7. This invention generates It will rapidly diffuse to neighboring single-atom sites, and these single-atom sites, especially those with unsaturated coordination environments, serve as another electron-rich center, enabling efficient and rapid activation. And decompose it into highly reactive hydroxyl radicals. Or other high-valence metal-oxygen species, the reaction equation is as follows M is a metal.

[0033] 8. This invention, electron cycling and "self-driving": single-atom sites in activation It is then oxidized (such as from) Become The catalyst nanoclusters can capture electrons from organic pollutants or water, rapidly reducing high-valence single atoms back to their initial low-valence states, thus completing the catalytic cycle; this nanocluster produces... Single-atom activation The closed-loop electron regeneration system can effectively reduce the amount of oxidant required to maintain the catalytic oxidation reaction rate. The synergistic effect of single-atom sites and nanoclusters constitutes a microreactor for a self-driven Fenton-like reaction. Attached Figure Description

[0034] Figure 1 This is a flowchart of a nanocluster, single-atom self-driven Fenton-like composite catalyst and its application proposed in this invention. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0037] Example 1

[0038] This embodiment provides a composite catalyst based on a nanocluster, single-atom self-driven Fenton system, and the specific implementation steps include:

[0039] Experimental materials:

[0040] Coconut shell activated carbon, nitric acid, phosphoric acid, ferric nitrate, copper nitrate, urea, trimethylphosphine, ruthenium trichloride, ethanol, and deionized water.

[0041] Experimental objective:

[0042] A Ru-supported Fe, Cu, Ce ternary single-atom and nanocluster synergistic catalyst was constructed to achieve a low-oxidant self-driven Fenton-like reaction under visible light and visible light-assisted conditions, and its degradation performance on antibiotics, dyes and phenolic pollutants was evaluated.

[0043] Experimental steps:

[0044] S1: Coconut shell activated carbon was immersed in an acid solution with a molar ratio of nitric acid, phosphoric acid and sulfuric acid of 1:1:1 and a total molar concentration of 1 mol / L. It was then placed in a 200W ultrasonic machine for ultrasonic treatment for 1 hour. After that, it was filtered to separate the solid and liquid. Finally, it was washed and dried to obtain N, S and P modified carbon-based support (NP-C).

[0045] S2: The transition metal salts ferric nitrate, copper nitrate and cerium nitrate are mixed in a molar ratio of 1.5:1:1. Then, thiourea, urea and trimethylphosphine are mixed in a molar ratio of 1:1:1 to form an organic ligand. The mixed metal salt and organic ligand are then mixed in a molar ratio of 1.2:1. Deionized water and ethanol are prepared in a volume ratio of 4:1 as solvents. Finally, the above mixture is dissolved in the solvent.

[0046] S3: The solution is transferred to a pressure reactor and hydrothermally reacted at 120°C for 6 hours to obtain the precursor impregnation solution;

[0047] S4: The obtained NSP-C support is added to the impregnation solution, and the mass ratio of its transition metal salt to the support is 6wt%. Then, it is stirred and impregnated at 50℃ for 6h. After filtration, separation and drying, the pre-impregnated solid is obtained.

[0048] S5: Ruthenium trichloride and platinum group metals are mixed at a total molar ratio of 1:20. Then, a platinum group metal spray solution is prepared at a total mass of 10 wt% of the pre-impregnated solids. Finally, the solution is sprayed onto the surface of the pre-impregnated carrier.

[0049] S6: Place the pre-impregnated carrier in a tube furnace, and set the heating rate of the tube furnace to 3℃ / min until it reaches 200℃, and hold it at that temperature for 2 hours. Then, introduce nitrogen and raise the temperature to 500℃ at a rate of 3℃ / min, and hold it at that temperature for 2 hours. Finally, introduce a mixed atmosphere of 20% hydrogen and 80% nitrogen, raise the temperature to 800℃ at a rate of 5℃ / min, and hold it at that temperature for 1 hour. Then, immediately force-cool the catalyst to obtain solid catalyst, and crush it to a mesh size of 300 or larger by ball milling to obtain catalyst particles.

[0050] Experimental results:

[0051] This embodiment prepared , Catalyst, in catalytic oxidation test, when When the ratio is 1:1, the hydrogen peroxide residue is 4.8%, and the COD removal rate reaches 54%; when When the ratio was increased to 1:2, the residual hydrogen peroxide content rose to 15.6%, but the COD removal rate significantly increased to 91%. The results indicate that this catalyst can achieve efficient degradation under appropriate oxidant conditions and possesses good performance characteristics. Utilize potential.

[0052] Example 2

[0053] This embodiment provides a composite catalyst based on a nanocluster and single-atom self-driven Fenton system, employing a Pt-supported Co single atom and nanocluster synergistic catalyst. Specific implementation steps include:

[0054] Experimental materials:

[0055] Coconut shell activated carbon, nitric acid, sulfuric acid, cobalt nitrate, thiourea, ethylenediaminetetraacetic acid, and chloroplatinic acid.

[0056] Experimental objective:

[0057] A synergistic catalyst of Co single atoms and nanoclusters supported on Pt was developed.

[0058] Experimental steps:

[0059] S1: Coconut shell activated carbon was immersed in an acid solution with a molar ratio of nitric acid and sulfuric acid of 1:1 and a total molar concentration of 1 mol / L. It was then placed in a 300W ultrasonic machine for ultrasonic treatment for 1 hour. After that, it was filtered to separate the solid and liquid. Finally, it was washed and dried to obtain N,S modified carbon-based support (NS-C).

[0060] S2: The transition metal salt cobalt nitrate was dissolved in an organic ligand composed of ethylenediaminetetraacetic acid and thiourea in a molar ratio of 1.3:1. The mixture was then dissolved in a mixed solvent with a volume ratio of deionized water: tert-butanol = 5:1. Finally, the solution was transferred to a pressure reactor and hydrothermally reacted at 140°C for 4 hours to obtain the precursor impregnation solution.

[0061] S3: Add the NS-C support to the impregnation solution, with the transition metal salt accounting for 8wt% of the support by mass. Then, stir and impregnate at 60℃ for 5h. Finally, filter, separate, and dry the solution to obtain the pre-impregnated solid.

[0062] S4: Prepare an 8wt% platinum group metal leaching solution by mixing chloroplatinic acid and transition metals in a total molar ratio of 1:25.

[0063] S5: The pre-impregnated carrier is placed in a tube furnace, and the heating rate of the tube furnace is set to 3℃ / min until it reaches 200℃, and then held at that temperature for 2 hours. Nitrogen is then introduced, and the temperature is raised to 550℃ at a rate of 5℃ / min, and held at that temperature for 4 hours. Finally, a mixed atmosphere of 20% hydrogen and 80% nitrogen is introduced, and the temperature is raised to 850℃ at a rate of 5℃ / min, and held at that temperature for 2 hours. After immediate forced cooling, the catalyst solid is obtained, and then crushed to a mesh size of 300 or larger by ball milling to obtain catalyst particles.

[0064] Experimental results:

[0065] This embodiment prepared Catalyst, test results show that, Under a 1:1 ratio, the hydrogen peroxide residue is as low as 2.7%, and the COD removal rate is 61%; when When the ratio is 1:2, with a hydrogen peroxide residue of 10.3%, the COD removal rate is further improved to 95%, demonstrating the excellent performance of this catalyst. Activation efficiency and high degradation activity.

[0066] Example 3

[0067] This embodiment provides a composite catalyst based on a nanocluster and single-atom self-driven Fenton system, employing Ru-supported Cu and Co single-atom and nanocluster synergistic catalysts. Specific implementation steps include:

[0068] Experimental materials:

[0069] Graphene oxide, sulfuric acid, phosphoric acid, copper nitrate, cobalt nitrate, thiourea, trimethylphosphine, ruthenium trichloride, ethanol, and deionized water.

[0070] Experimental objective:

[0071] A Ru-supported Cu and Co single-atom and nano-cluster synergistic catalyst was developed.

[0072] Experimental steps:

[0073] S1: Graphene oxide was immersed in an acid solution with a molar ratio of nitric acid and phosphoric acid of 1:1 and a total molar concentration of 1 mol / L. It was then placed in a 200W ultrasonic machine for ultrasonic treatment for 1 hour. After that, it was filtered to separate the solid and liquid. Finally, it was washed and dried to obtain S,P modified carbon-based support (SP-C).

[0074] S2: Mix the transition metal salts copper nitrate and cobalt nitrate in a molar ratio of 1.5:1, then combine thiourea and trimethylphosphine in a molar ratio of 1:1 to form an organic ligand, then mix the mixed metal salt and organic ligand in a molar ratio of 1.5:1, then prepare deionized water and ethanol as solvents in a volume ratio of 3:1, and finally dissolve the above mixture in the solvent.

[0075] S3: The solution is transferred to a pressure reactor and hydrothermally reacted at 180°C for 6 hours to obtain the precursor impregnation solution;

[0076] S4: Add the NS-C support to the impregnation solution, the transition metal salt of which accounts for 11 wt% of the support by mass. Then stir and impregnate at 60°C for 5 h. After filtration, separation and drying, the pre-impregnated solid is obtained.

[0077] S5: Ruthenium trichloride and platinum group metals are mixed at a total molar ratio of 1:20. Then, a platinum group metal spray solution is prepared with the total mass of the solution accounting for 8 wt% of the pre-impregnated solids. Finally, the solution is sprayed onto the surface of the pre-impregnated carrier.

[0078] S6: Place the pre-impregnated carrier in a tube furnace, and set the heating rate of the tube furnace to 3℃ / min until it reaches 200℃, and hold it at that temperature for 2 hours. Then, introduce nitrogen and raise the temperature to 500℃ at a rate of 5℃ / min, and hold it at that temperature for 2 hours. Finally, introduce a mixed atmosphere of 20% hydrogen and 80% nitrogen, raise the temperature to 900℃ at a rate of 5℃ / min, and hold it at that temperature for 3 hours. Then, immediately force-cool the catalyst to obtain solid catalyst, and crush it to a mesh size of 300 or larger by ball milling to obtain catalyst particles.

[0079] Experimental results:

[0080] This embodiment prepared Catalyst, performance tests show that, When the ratio is 1:1, the hydrogen peroxide residue is 3.4%, and the COD removal rate is 68%; At a ratio of 1:2, with a hydrogen peroxide balance of 9.8%, the COD removal rate reached as high as 98%. This catalyst exhibited the highest catalytic degradation efficiency among all comparative examples.

[0081] Example 4

[0082] This embodiment provides a catalyst oxidation performance test, and the specific implementation steps include:

[0083] Experimental materials:

[0084] Bisphenol A aqueous solution, NaOH, potassium permanganate, manganese dioxide, hydrogen peroxide.

[0085] Experimental objective:

[0086] Test the oxidation performance of the catalyst.

[0087] Experimental steps:

[0088] S1: Prepare a 60 mg / L bisphenol A aqueous solution as a simulated wastewater. ≈150 mg / L, then the original water was adjusted to pH=6 with 20wt% NaOH solution;

[0089] S2: Add catalyst, with a catalyst dosage of 0.5 g / L;

[0090] S3: Let the aeration intensity of the fluidized catalyst be... The reactor has a height-to-diameter ratio (H / D) of 3-8:1 and a residence time of 1 hour.

[0091] S4: The concentration of hydrogen peroxide in water was determined by potassium permanganate titration. The hydrogen peroxide residue was calculated as (1 - (concentration after reaction / initial concentration after reaction)) × 100%.

[0092] S5: The removal rate of bisphenol A was determined by the dichromate method, and the results were compared before and after the reaction. The concentration of hydrogen peroxide was determined, and the water sample after the reaction was subjected to manganese dioxide reaction to fully decompose the residual hydrogen peroxide in the water, so as to eliminate the impact of residual hydrogen peroxide on COD.

[0093] S6: Prepare its =1:1 and 1:2.

[0094] Experimental results: See Table 1 for details.

[0095] Table 1: Test Results of Example 4

[0096]

[0097] This embodiment demonstrates a unified methodology for testing catalyst performance. The results are summarized in Table 1. A comprehensive comparison shows that the COD removal rates of the various nanoclusters and single-atom composite catalysts prepared in this invention are significantly higher than those of the traditional Fenton process and Comparative Example 1, which has structural defects, under different hydrogen peroxide dosages. This fully demonstrates the significant advantages and universality of the catalyst system of this invention in reducing oxidant consumption and improving pollutant degradation efficiency.

[0098] Example 5

[0099] This embodiment provides a photo-assisted ternary metal catalyst and its high-efficiency degradation performance. The specific implementation steps include:

[0100] Experimental materials:

[0101] Coconut shell activated carbon, nitric acid, phosphoric acid, ferric nitrate, copper nitrate, cerium nitrate, urea, trimethylphosphine, ruthenium trichloride, ethanol, and deionized water.

[0102] Experimental objective:

[0103] By utilizing Ru-supported ternary single-atom and nano-cluster catalysts, and under visible light assistance, a highly efficient Fenton-like reaction with near-zero oxidant addition was achieved.

[0104] Experimental steps:

[0105] S1: Coconut shell activated carbon was immersed in an acid solution with a molar ratio of nitric acid and phosphoric acid of 1:1 and a total molar concentration of 1 mol / L. It was ultrasonically treated at 250W for 1.5 hours, filtered, washed with deionized water until neutral, and dried at 120℃ to constant weight to obtain N and P co-modified carbon-based support (NP-C).

[0106] S2: Mix the transition metal salts ferric nitrate, copper nitrate and cerium nitrate in a molar ratio of 1.5:1:0.5, and combine urea and trimethylphosphine in a molar ratio of 1:1 to form an organic ligand. Then, mix the mixed metal salt and the organic ligand in a total molar ratio of 1.2:1 and dissolve them in a mixed solvent of deionized water and ethanol in a volume ratio of 4:1.

[0107] S3: Transfer the above solution into a pressure reactor and hydrothermally react at 150°C for 8 hours to obtain a ternary metal precursor impregnation solution.

[0108] S4: The NP-C carrier obtained in S1 was added to the impregnation solution and impregnated at 60°C with stirring for 8 hours. Then, it was filtered, separated, and dried at 120°C to obtain the pre-impregnated solid.

[0109] S5: Prepare a ruthenium trichloride aqueous solution and spray it onto the surface of the preimpregnated carrier using a double-cone rotary impregnator. The mass of the spray solution accounts for 9 wt% of the preimpregnated solid. After spraying, a dry precursor is obtained directly.

[0110] S6: The obtained precursor was placed in a tube furnace for gradient pyrolysis. The temperature was increased to 180°C at 3°C / min in air and held for 1.5 hours. Then, the temperature was increased to 550°C at 5°C / min and held for 3 hours in a nitrogen atmosphere. Next, the temperature was switched to a 10% hydrogen / 90% nitrogen mixed atmosphere, and the temperature was increased to 850°C at 5°C / min and held for 2 hours. After the reaction was completed, the mixture was forcibly cooled, and the resulting solid catalyst was ball-milled to a fineness of over 300 mesh. Catalyst finished product.

[0111] Experimental results: See Table 2 for details.

[0112] Table 2: Test Results of Example 5

[0113]

[0114] A visible light-assisted ternary metal catalyst was prepared. Subsequently, a synergistic system of Fe, Cu, and Ce single atoms and nanoclusters was constructed on a carbon support co-modified with N and P, and visible light irradiation was introduced to achieve a Fenton-like reaction under near-neutral conditions without the need for additional hydrogen peroxide. After treating bisphenol A simulated wastewater with an initial COD of 150 mg / L for 60 minutes, the COD removal rate reached as high as 70%, and no hydrogen peroxide residue was detected in the post-reaction water sample. The catalyst maintained an activity of over 89% after five consecutive uses.

[0115] Comparative Example 1

[0116] This embodiment provides a Ru-supported Fe and Cu synergistic catalyst preparation method, the specific implementation steps of which include:

[0117] Experimental materials:

[0118] Coconut shell activated carbon, ferric nitrate, copper nitrate, ruthenium trichloride, and platinum group metals.

[0119] Experimental objective:

[0120] The carbon-based support is not pretreated, the precursor impregnation solution does not contain organic ligands, and the pre-impregnated solid is calcined at a constant heating rate to the maximum pyrolysis temperature, without staged gradient calcination.

[0121] Experimental steps:

[0122] S1: The coconut shell activated carbon carrier is obtained by washing with deionized water and drying without acid solution pretreatment;

[0123] S2: Mix transition metal salts ferric nitrate and copper nitrate in a molar ratio of 1.5:1, and then heat and stir until completely dissolved to obtain a precursor impregnation solution;

[0124] S3: Add coconut shell carbon carrier to 50℃ impregnation solution and stir continuously for 6h. The mass ratio of transition metal salt to carrier is 6wt%. After filtration and drying, pre-impregnated solid is obtained.

[0125] S4: Ruthenium trichloride and platinum group metals are mixed at a total molar ratio of 1:20. Then, a platinum group metal spray solution is prepared with the total mass of the solution accounting for 10 wt% of the pre-impregnated solids. Finally, the solution is sprayed onto the surface of the pre-impregnated carrier.

[0126] S5: Place the pre-impregnated carrier in a tube furnace and set the heating curve of the tube furnace to 5℃ / min until it reaches 800℃, and keep it at that temperature for 1 hour. Then immediately force-cool it to obtain solid catalyst, and crush it to more than 300 mesh by ball milling to finally obtain catalyst particles.

[0127] Experimental results: See Table 6 for details.

[0128] Table 6: Test Results of Comparative Example 1

[0129]

[0130] Comparative Example 1, lacking key steps such as carrier pretreatment, organic ligands, and gradient pyrolysis, has obvious defects in its catalyst structure, resulting in low hydrogen peroxide utilization and a COD removal rate of only 38%-65%, which is significantly lower than all other examples.

[0131] Example 1 utilizes the synergistic structure and effect of Ru and Fe / Cu bimetallic single atoms and nanoclusters to achieve highly efficient catalytic oxidation performance on N and P co-modified coconut shell activated carbon support. It maintains a COD removal rate of 54% even with a low hydrogen peroxide dosage, demonstrating good basic catalytic activity and stability.

[0132] Example 2 utilizes precise coordination of Pt and Co single-metal sites with nanoclusters, relying on a support modified with N and S dual heteroatoms, to significantly improve... The activation efficiency is high; at a 1:1 addition ratio, the hydrogen peroxide residue is only 2.7%, demonstrating excellent oxidant utilization.

[0133] Example 3 employs a synergistic strategy of Ru, Cu, and Co multi-metals combined with an SP-type support to achieve the best performance among current traditional Fenton-like systems on a graphene oxide-based support. When the ratio is 1:2, the removal rate reaches as high as 98%, highlighting the synergistic effect of metal combination and carrier regulation.

[0134] Example 4 employs a systematic and standardized performance evaluation method, constructs a unified testing platform, and powerfully demonstrates the universal advantages and engineering applicability potential of the catalyst system of the present invention under wide pH range and low oxidant dependence conditions through multiple sets of comparative data.

[0135] Comparative Example 1 uses a simplified preparation process, resulting in a catalyst with a coarse structure and missing active sites, leading to a hydrogen peroxide residue of 22.5%-35.2% and a COD removal rate of only 38%-65%. This, in turn, confirms the key roles of support modification, ligand complexation, and programmed pyrolysis in the system of this invention.

[0136] Comparing the examples and comparative examples, Example 1 achieved the optimal balance between catalytic activity and preparation cost, cleverly improving the overall performance and economy of the catalyst through bimetallic loading and heteroatom anchoring, making it suitable for medium-intensity treatment of conventional industrial wastewater; although Example 2... The activation efficiency is extremely high, but it relies on the precious metal Pt, resulting in high costs. Example 3 uses a graphene support and a ternary metal design, achieving excellent performance, but the raw material and process costs are correspondingly increased. Example 4 employs a standardized evaluation system, providing a reliable basis for catalyst selection in different scenarios. The comparative examples highlight the functional limitations of traditional unstructured catalysts. Therefore, this invention, through a three-in-one structured design of "support modification-ligand complexation-gradient pyrolysis," successfully constructs a high-performance, low-reagent-consumption, and widely adaptable self-driven Fenton-like catalytic system, possessing significant industrial application and promotion value.

[0137] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.

[0138] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nanocluster, single-atom self-driven Fenton-like system composite catalyst, characterized in that, Specifically comprising the following steps: S1: the porous carbon-based carrier is immersed in a sulfuric acid, phosphoric acid, nitric acid solution for ultrasonic treatment, the ultrasonic power is set to 100-500 W, the ultrasonic time is 1-2 h, then it is subjected to suction filtration, separation, and then washed with deionized water until the suction filtrate is neutral, and finally it is dried at 120 DEG C until the mass is constant, to obtain an N, S, P modified carbon-based carrier; S2: the transition metal salt and the organic ligand are dissolved in a solvent, then they are stirred uniformly, and finally a composite metal precursor impregnation solution is obtained; S3: the pretreated carrier obtained in S1 is added to the metal precursor solution prepared in S2 for impregnation, then it is placed in a 40-80 DEG C heating and stirring impregnation for 4-12 hours, then it is subjected to suction filtration, separation, and finally it is placed in a 120 DEG C oven to dry until the weight is constant, and then a pre-impregnated carrier solid is obtained; S4: the platinum group metal salt is prepared into an aqueous solution, then it is placed in a double-cone rotary impregnator for spraying impregnation on the surface of the pre-impregnated carrier; S5: the catalyst precursor obtained in S4 is transferred into a rotary furnace, and a one-pot gradient pyrolysis method is used for high-temperature staged calcination treatment under the protection of a certain atmosphere, and the single-atom site and nanocluster are simultaneously constructed by controlling the calcination atmosphere, the temperature rising program, and the holding time; S6: the catalyst solid obtained in S5 is broken by horizontal ball milling to more than 300 mesh, and then the particles below 300 mesh are separated by a high-frequency vibration screen as a catalyst product, and the particles above 300 mesh are subjected to secondary ball milling to a particle size of less than 300 mesh.

2. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The porous carbon-based carrier in S1 is a carbon-based material with high specific surface area and rich defects, and the carrier is rich in N, S, and P as anchor sites of heteroatoms, which can stabilize single atoms and nanoclusters.

3. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The acid solution in S1 includes one or more of nitric acid, sulfuric acid, and hydrochloric acid, and the concentration is 0.5-2 mol / L.

4. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The transition metal in S2 is one or more of nitrate salts of Fe, Co, Ni, Cu, Mn, and Ce; the organic ligand is a nitrogen-containing ligand including urea, thiourea, ethylenediaminetetraacetic acid, ethylenediamine, and o-phenanthroline; the sulfur ligand includes thiourea, and the phosphorus ligand includes trimethylphosphine and tricyclohexylphosphine.

5. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The concentration of the transition metal salt in S2 is 0.01-0.1 mol / L; and the molar ratio of the three transition metal salts is 1.5-3:1:1; the molar ratio of the three organic ligands is 1:1:1; the total molar ratio of the transition metal salt and the organic ligand is 1.2:1; and the solvent is deionized water, ethanol, and tert-butanol.

6. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The total mass of the transition metal salt in the impregnation solution in S3 accounts for 5-12 wt% of the mass of the dry carrier.

7. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The platinum group metal salt in S4 is one of chloroplatinic acid and ruthenium trichloride, and the molar ratio of the platinum group metal salt to the transition metal salt in S2 is 1:15-25; the double-cone rotary impregnator has a drying function, and the dried catalyst precursor can be directly obtained after spraying impregnation.

8. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The gradient pyrolysis calcination in S5 is divided into air atmosphere, nitrogen atmosphere and hydrogen-nitrogen mixed atmosphere; the air atmosphere is heated to 150-200 DEG C at a heating rate of 2-5 DEG C / min, and then kept for 1-2 h; the nitrogen atmosphere is heated to 400-600 DEG C at a heating rate of 3-8 DEG C / min, and then kept for 2-4 h; the hydrogen-nitrogen mixed atmosphere is heated to 700-900 DEG C at a heating rate of 2-5 DEG C / min, and then kept for 1-3 h.

9. The nanocluster, single-atom self-driven Fenton-like system composite catalyst according to claim 1, characterized in that, The air atmosphere, nitrogen atmosphere and hydrogen-nitrogen atmosphere in S5 all have a gas flow rate of 80-200 mL / min.

10. The use of the nanocluster, single-atom self-driven Fenton system composite catalyst according to claim 1, characterized in that, The synergistic effect of nanoclusters and single atoms has achieved arrive arrive It has a high efficiency and rapid conversion rate, and then effectively degrades organic pollutants such as antibiotics and phenols.

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