Spin synergy MnN3 / CoN4 double-monatomic ozone catalytic microsphere as well as preparation method and application thereof

Abstract

The invention provides spin synergistic MnN3 / CoN4 double-monatomic ozone catalytic microspheres as well as a preparation method and application thereof. The spin synergistic MnN3 / CoN4 double-monatomic ozone catalytic microsphere solves the problems that a traditional water treatment process is poor in removal effect on micropollutants which are difficult to degrade and are complex in chemical structure, high in degradation resistance and outstanding in environmental durability, and an existing ozone catalyst is insufficient in active site exposure, low in ozone and active site mass transfer efficiency, weak in double-atom synergistic effect, low in cost and the like. The technical problems of limited ozone catalytic efficiency, insufficient pollutant removal capacity, long reaction retention time and difficulty in meeting the requirements of high-efficiency water purification in the scenes of drinking water deep treatment, reclaimed water reuse, industrial wastewater recycling and the like in the prior art are solved. The invention further provides a preparation method and application of the spin synergistic MnN3 / CoN4 double-monatomic ozone catalytic microspheres.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically relating to spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres, their preparation methods, and applications. Background Technology

[0002] Water scarcity, escalating water pollution, and deteriorating aquatic ecosystems have become key challenges hindering sustainable social development. The widespread presence of persistent micropollutants poses a serious threat to water safety and human health. These pollutants originate from various sectors of production and daily life, are frequently detected in global water environments, and are characterized by complex chemical structures, strong resistance to degradation, and significant environmental persistence. Long-term exposure may lead to a series of adverse effects, including endocrine disruption, genotoxicity, and even teratogenicity, carcinogenicity, and mutation, making them a key challenge in the current water treatment field.

[0003] Traditional water treatment processes generally have limitations in dealing with recalcitrant micropollutants: physical processes such as coagulation, sedimentation, and filtration can only remove some suspended pollutants, with minimal effect on dissolved micropollutants; chlorination disinfection processes have limited oxidation capacity and easily generate more toxic chlorinated byproducts, exacerbating water quality safety risks; activated carbon adsorption processes are limited by adsorption capacity and require frequent regeneration, leading to increased operating costs; biological treatment processes can only degrade some biodegradable pollutants and are ineffective against recalcitrant micropollutants. These inherent defects in these processes have prevented an effective solution to the purification problem of recalcitrant micropollutants in the aquatic environment, necessitating the development of new and efficient water treatment technologies.

[0004] Ozone catalytic oxidation has become a preferred technology for purifying recalcitrant micropollutants due to its advantages such as simple operation, strong environmental adaptability, high treatment efficiency, and no secondary pollution. The core of this process lies in the performance of the catalyst; a highly efficient catalyst can accelerate ozone decomposition and rapidly generate highly reactive secondary free radicals, thereby achieving deep oxidation and mineralization of recalcitrant pollutants. However, existing ozone catalysts generally suffer from insufficient exposure of active sites, low mass transfer efficiency between ozone and active sites, and weak biatomic synergistic effects, which limit ozone catalytic efficiency and make it difficult to achieve efficient pollutant removal within a short residence time. Therefore, developing a novel ozone catalyst with high catalytic efficiency, strong pollutant removal capacity, and short residence time, along with related water treatment technologies, has become a key requirement for overcoming the current bottlenecks in the treatment of recalcitrant micropollutants. Summary of the Invention

[0005] This invention aims to at least solve one of the aforementioned technical problems existing in the prior art. To this end, this invention provides a spin-synergistic MnN3 / CoN4 dual-monoatom ozone catalytic microsphere, which solves the technical problems of poor removal efficiency of recalcitrant micropollutants with complex chemical structures, strong degradation resistance, and significant environmental persistence in traditional water treatment processes. Existing ozone catalysts suffer from insufficient exposure of active sites, low mass transfer efficiency between ozone and active sites, and weak dual-atom synergistic effects, resulting in limited ozone catalytic efficiency, insufficient pollutant removal capacity, and long reaction residence time, making it difficult to meet the high-efficiency water purification requirements in scenarios such as advanced drinking water treatment, reclaimed water reuse, and industrial wastewater resource utilization.

[0006] This invention also provides a method for preparing spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres.

[0007] This invention also provides the application of spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres in wastewater treatment.

[0008] The first aspect of the present invention provides spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres, comprising a silicate-based spherical support and a spin-coordinated MnN3 / CoN4 dual single-atom catalyst supported on the surface of the silicate-based spherical support, wherein the loading amount of the spin-coordinated MnN3 / CoN4 dual single atoms is 0.1 mg / g to 5.0 mg / g.

[0009] The spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres of the present invention have at least the following beneficial effects: The spin-coordinated MnN3 / CoN4 dual-single-atom ozone catalytic microspheres of this invention have a core active site that is a spin-coordinated MnN3 / CoN4 dual-single-atom catalyst. Utilizing the spin-coordinated Mn-Co bimetallic single-atom site within the spin-coordinated MnN3 / CoN4 dual-single-atom, rapid adsorption and efficient catalytic decomposition of ozone molecules are achieved. The generated secondary free radicals exhibit higher degradation and mineralization capabilities for harmful pollutants compared to ozone molecules. Furthermore, ozone also possesses multiple functions such as sterilization, algae removal, and disinfection, effectively ensuring water quality safety.

[0010] The silicate-based spherical support achieves uniform loading of MnN3 / CoN4 dual single-atom catalysts by utilizing hydration-induced solidification and gelation properties. The support structure is stable, providing solid support for the catalytic reaction and preventing catalyst loss during water treatment stirring and aeration, thus ensuring the stability of catalytic efficiency.

[0011] The core active site is a spin-coordinated MnN3 / CoN4 dual single atom. The synergistic effect between the two atoms can promote the co-adsorption and synergistic catalytic decomposition of ozone molecules. Combined with the regulation of electronic structure by defect sites, it can enhance the electronic interaction with ozone molecules, so that ozone is almost 100% converted into highly active secondary free radicals, which can significantly improve the degradation and mineralization of recalcitrant micropollutants.

[0012] With a loading range of 0.1 mg / g to 5.0 mg / g, it ensures sufficient active site density to efficiently handle organic micropollutants with concentrations of 0.1 mg C / L to 5 mg C / L, while avoiding resource waste caused by excessive catalyst. At the same time, the porous characteristics of the silicate support and the catalyst's own ultra-large specific surface area provide a sufficient contact platform for the reaction, shortening the reaction residence time (efficient removal can be achieved in 300s to 600s).

[0013] The composite catalytic microspheres of this invention are suitable for various scenarios such as advanced drinking water treatment, reclaimed water reuse, and industrial wastewater (pharmaceutical, printing and dyeing, etc.) treatment. They can efficiently remove recalcitrant pollutants such as nitrobenzene and benzotriazole, and ensure water quality safety by leveraging the bactericidal, algae-removing, and disinfecting effects of ozone. In industrial wastewater treatment, they can also improve the biodegradability of effluent and contribute to the resource-based regeneration of water resources.

[0014] According to some embodiments of the present invention, the specific surface area of ​​the spin-coordinated MnN3 / CoN4 dual single-atom catalyst is 1250 m². 2 / g~1600m 2 / g.

[0015] According to some embodiments of the present invention, the specific surface area of ​​the spin-coordinated MnN3 / CoN4 dual single-atom catalyst is 1250 m². 2 / g、1300m 2 / g, 1350m 2 / g, 1400m 2 / g, 1450m 2 / g, 1500m 2 / g, 1550m 2 / g, 1600m 2 Any value in / g, such as 1400m 2 / g, or any range of values ​​formed by both, such as 1350m 2 / g~1500m 2 / g.

[0016] According to some embodiments of the present invention, the diameter of the silicate-based spherical carrier is 0.1 cm to 5.0 cm.

[0017] According to some embodiments of the present invention, the diameter of the silicate-based spherical carrier is any value among 0.1cm, 0.5cm, 1.0cm, 1.5cm, 2.0cm, 2.5cm, 3.0cm, 3.5cm, 4.0cm, 4.5cm, and 5.0cm, such as 1.0cm, or any range formed by both, such as 2.0cm to 3.5cm.

[0018] A second aspect of the present invention provides a method for preparing spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres of the present invention, comprising the following steps: S1: Prepare an N,N-dimethylformamide solution containing zinc nitrate hexahydrate, dimethylimidazole and manganese acetate dihydrate, allow it to stand for reaction, and then recover the generated crystalline substance. S2: The crystalline material is subjected to a first calcination treatment under a protective gas atmosphere to obtain a powder sample, the powder sample is acid etched, and then the powder sample is recovered. S3: The obtained solid powder is subjected to a second calcination treatment under a protective gas atmosphere. The calcined sample is dispersed in a mixed solution containing cyanamide, cobalt chloride and isopropanol. The powder sample is then recovered and subjected to a third calcination under a protective gas atmosphere to obtain the spin-coordinated MnN3 / CoN4 dual single-atom catalyst. S4: Silicate powder is mixed with water to form a slurry, which is then granulated to obtain a spherical support. Utilizing the gelation properties of silicate, the spin-coordinated MnN3 / CoN4 dual single-atom catalyst is loaded onto the surface of the spherical support. After curing, the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres are obtained.

[0019] According to some embodiments of the present invention, the concentration of zinc nitrate hexahydrate in the solution of step S1 is 80 mmol / L to 160 mmol / L.

[0020] According to some embodiments of the present invention, in the solution of step S1, the concentration of zinc nitrate hexahydrate is any value among 80 mmol / L, 90 mmol / L, 100 mmol / L, 110 mmol / L, 120 mmol / L, 130 mmol / L, 140 mmol / L, 150 mmol / L, and 160 mmol / L, such as 120 mmol / L, or any range formed by both, such as 100 mmol / L to 140 mmol / L.

[0021] According to some embodiments of the present invention, the concentration of dimethylimidazole in the solution of step S1 is 40 mmol / L to 80 mmol / L.

[0022] According to some embodiments of the present invention, in the solution of step S1, the concentration of dimethylimidazole is any value among 40 mmol / L, 45 mmol / L, 50 mmol / L, 55 mmol / L, 60 mmol / L, 65 mmol / L, 70 mmol / L, 75 mmol / L, and 80 mmol / L, such as 60 mmol / L, or any range formed by both, such as 50 mmol / L to 70 mmol / L.

[0023] According to some embodiments of the present invention, the concentration of manganese acetate dihydrate in the solution of step S1 is 4 mmol / L to 10 mmol / L.

[0024] According to some embodiments of the present invention, the concentration of manganese acetate dihydrate in the solution of step S1 is any value among 4 mmol / L, 5 mmol / L, 6 mmol / L, 7 mmol / L, 8 mmol / L, 9 mmol / L, and 10 mmol / L, such as 7 mmol / L, or any range formed by both, such as 5 mmol / L to 9 mmol / L.

[0025] According to some embodiments of the present invention, in step S1, the time for the static reaction is 8 to 24 hours.

[0026] According to some embodiments of the present invention, in step S1, the settling reaction time is any value among 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, and 24h, such as 12h, or any range formed by both, such as 10h to 18h.

[0027] According to some embodiments of the present invention, in step S1, the temperature of the static reaction is 25~120°C.

[0028] According to some embodiments of the present invention, in step S1, the temperature of the static reaction is any value among 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, and 120°C, such as 60°C, or any range formed by both, such as 40°C to 90°C.

[0029] According to some embodiments of the present invention, in step S1, the generated crystalline material is recovered, washed with ethanol, and dried.

[0030] According to some embodiments of the present invention, in step S2, the temperature of the first calcination treatment is 1000~1200℃.

[0031] According to some embodiments of the present invention, in step S2, the temperature of the first calcination treatment is any value among 1000℃, 1050℃, 1100℃, 1150℃, and 1200℃, such as 1100℃, or any range formed by both, such as 1050℃~1150℃.

[0032] According to some embodiments of the present invention, in step S2, the time for the first calcination treatment is 30~90 min.

[0033] According to some embodiments of the present invention, in step S2, the time for the first calcination treatment is any value among 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, and 90 min, such as 60 min, or any range formed by both, such as 40 min to 70 min.

[0034] According to some embodiments of the present invention, in step S2, the acid etching process takes 2 to 5 hours.

[0035] According to some embodiments of the present invention, in step S2, the acid etching time is any value of 2h, 3h, 4h, 5h, such as 3h, or any range of two, such as 2.5h to 4.5h.

[0036] According to some embodiments of the present invention, in step S2, the temperature of the acid etching process is 50~80°C.

[0037] According to some embodiments of the present invention, in step S2, the temperature of the acid etching process is any value among 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, and 80°C, such as 65°C, or any range formed by both, such as 55°C to 75°C.

[0038] According to some embodiments of the present invention, in step S2, the reagent for acid etching is sulfuric acid.

[0039] According to some embodiments of the present invention, in step S2, the acid concentration of the acid etching treatment is 0.05~1.0 mol / L.

[0040] According to some embodiments of the present invention, in step S2, the acid concentration for acid etching is any value among 0.05 mol / L, 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, and 1.0 mol / L, such as 0.5 mol / L, or any range formed by both, such as 0.2 mol / L to 0.8 mol / L.

[0041] According to some embodiments of the present invention, in step S2, after acid etching, the powder sample is recovered, washed with deionized water, and dried.

[0042] According to some embodiments of the present invention, in step S3, the temperature of the second calcination treatment is 900~1100℃.

[0043] According to some embodiments of the present invention, in step S3, the temperature of the second calcination treatment is any value among 900°C, 950°C, 1000°C, 1050°C, and 1100°C, such as 1000°C, or any range formed by both, such as 950°C to 1050°C.

[0044] According to some embodiments of the present invention, in step S3, the second calcination treatment time is 90~180 min.

[0045] According to some embodiments of the present invention, in step S3, the time for the second calcination treatment is any value among 90 min, 100 min, 120 min, 140 min, 150 min, 160 min, and 180 min, such as 120 min, or any range formed by both, such as 100 min to 160 min.

[0046] According to some embodiments of the present invention, in step S3, the temperature of the third calcination treatment is 1000~1200℃.

[0047] According to some embodiments of the present invention, in step S3, the temperature of the third calcination treatment is any value among 1000℃, 1050℃, 1100℃, 1150℃, and 1200℃, such as 1100℃, or any range formed by both, such as 1050℃~1150℃.

[0048] According to some embodiments of the present invention, in step S3, the time for the third calcination treatment is 30~90 min.

[0049] According to some embodiments of the present invention, in step S3, the time for the third calcination treatment is any value among 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, and 90 min, such as 60 min, or any range formed by both, such as 40 min to 70 min.

[0050] According to some embodiments of the present invention, in step S3, the concentration of cyanamide in the mixed solution is 20 mmol / L to 40 mmol / L.

[0051] According to some embodiments of the present invention, in step S3, the concentration of cyanamide in the mixed solution is any value among 20 mmol / L, 25 mmol / L, 30 mmol / L, 35 mmol / L, and 40 mmol / L, such as 30 mmol / L, or any range formed by both, such as 25 mmol / L to 35 mmol / L.

[0052] According to some embodiments of the present invention, in step S3, the concentration of cobalt chloride in the mixed solution is 0.2 mmol / L to 1.0 mmol / L.

[0053] According to some embodiments of the present invention, in step S3, the concentration of cobalt chloride in the mixed solution is any value among 0.2 mmol / L, 0.3 mmol / L, 0.4 mmol / L, 0.5 mmol / L, 0.6 mmol / L, 0.7 mmol / L, 0.8 mmol / L, 0.9 mmol / L, and 1.0 mmol / L, such as 0.5 mmol / L, or any range formed by both, such as 0.3 mmol / L to 0.8 mmol / L.

[0054] According to some embodiments of the present invention, in step S3, the concentration of isopropanol in the mixed solution is 25-75% (referring to volume concentration, the volume ratio of isopropanol to water). According to some embodiments of the present invention, in step S3, the concentration of isopropanol in the mixed solution is any value among 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, and 75%, such as 50%, or any range formed by both, such as 35% to 65%.

[0055] According to some embodiments of the present invention, in step S4, the mass ratio of silicate powder to water is (5~20):1.

[0056] The main components are silicates such as dicalcium silicate and tricalcium silicate. Silica such as aluminum silicate and ferric silicate can also be used.

[0057] According to some embodiments of the present invention, in step S4, the curing temperature is 20~60°C.

[0058] According to some embodiments of the present invention, in step S4, the curing temperature is any value among 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, and 60°C, such as 40°C, or any range formed by both, such as 30°C to 50°C.

[0059] According to some embodiments of the present invention, the curing time is 6 to 24 hours.

[0060] According to some embodiments of the present invention, the curing time is any value among 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, and 24h, such as 12h, or any range formed by both, such as 8h to 18h.

[0061] The preparation method of the present invention does not require expensive equipment and complex process control, the reaction conditions are not harsh, the raw materials are readily available, the production cost is low, and it is easy to industrialize.

[0062] A third aspect of the present invention provides a wastewater treatment method, the steps of which include adding the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres of the present invention and the wastewater to be treated into an ozone contact reactor for reaction, and after the reaction, recovering the catalyst from the water by filtration.

[0063] According to some embodiments of the present invention, the pollutants in the wastewater to be treated are nitrobenzene, benzotriazole, p-hydroxybenzoic acid or 4-nitrophenol.

[0064] The wastewater treatment method of this invention utilizes a diatomic catalyst with a high level of active site exposure as an ozone catalyst. This high site exposure significantly circumvents the mass transfer process between ozone molecules and active sites, enhancing the ozone catalytic process. Furthermore, the effective synergistic effect between the diatomic sites enables co-adsorption and synergistic catalytic decomposition of ozone molecules. Simultaneously, numerous defect sites are constructed near the Mn-Co diatomic sites. These defect sites effectively modulate the electronic structure of the Mn-Co diatomic sites, significantly enhancing the electronic interaction between the diatomic sites and ozone molecules, thus strengthening the ozone catalytic process. In addition, this catalyst possesses a large specific surface area, providing a sufficient reaction platform for the ozone catalytic reaction. Using this method, highly efficient removal of recalcitrant micropollutants with different structural properties, such as nitrobenzene, benzotriazole, p-hydroxybenzoic acid, and 4-nitrophenol, can be achieved within a very short residence time. Therefore, this invention represents an advanced water treatment technology for recalcitrant micropollutants in water, which can be widely applied to drinking water treatment, municipal wastewater reuse, and industrial wastewater resource recovery.

[0065] The wastewater treatment method of this invention can be applied to advanced drinking water treatment. It can be applied after the filtration process in drinking water plants, utilizing a spin-coordinated MnN3 / CoN4 dual-monatomic catalytic ozonation process to effectively remove recalcitrant organic micropollutants from the water. Simultaneously, ozone has bactericidal, disinfectant, and algae-removing effects, ensuring the safety of drinking water supply.

[0066] The wastewater treatment method of this invention can be applied to the advanced treatment and reuse of reclaimed water. It can be applied after the secondary sedimentation process in municipal wastewater treatment, utilizing a spin-coordinated MnN3 / CoN4 dual single-atom catalytic ozonation process to effectively remove recalcitrant organic micropollutants from the water, ensuring the quality of reclaimed water reuse.

[0067] The wastewater treatment method of this invention can be applied to the efficient treatment and reuse of industrial wastewater, such as high-concentration industrial wastewater from pharmaceutical manufacturing, dyeing and printing, aquaculture, and electroplating, which is difficult to treat effectively using biochemical processes. It can be applied after conventional physical pretreatment processes (such as coagulation-sedimentation) to achieve effective removal of recalcitrant organic pollutants in water through a spin-synergistic MnN3 / CoN4 dual-monoatom catalytic ozonation process. This reduces the concentration of organic matter in the effluent while improving its biodegradability, thus realizing the resource-based regeneration of industrial wastewater.

[0068] During the reaction, ozone aeration is carried out using a porous aeration device, and the reaction process is thoroughly stirred.

[0069] According to some embodiments of the present invention, aeration is performed during the reaction process using an ejector, an aeration plate, or an aeration head.

[0070] According to some embodiments of the present invention, the concentration of gaseous ozone during the reaction process is 0.01~15 mg / L.

[0071] According to some embodiments of the present invention, during the reaction process, the concentration of gaseous ozone is any value among 0.01 mg / L, 2 mg / L, 4 mg / L, 6 mg / L, 8 mg / L, 10 mg / L, 12 mg / L, 14 mg / L, and 15 mg / L, such as 8 mg / L, or any range formed by both, such as 4 mg / L to 12 mg / L.

[0072] According to some embodiments of the present invention, the flow rate of ozone gas is 100 mL / min to 400 mL / min.

[0073] According to some embodiments of the present invention, the flow rate of ozone gas is any value among 100 mL / min, 150 mL / min, 200 mL / min, 250 mL / min, 300 mL / min, 350 mL / min, and 400 mL / min, such as 250 mL / min, or any range formed by both, such as 150 mL / min to 350 mL / min.

[0074] According to some embodiments of the present invention, the residence time during the reaction is 300s to 600s.

[0075] According to some embodiments of the present invention, during the reaction process, the residence time is any value among 300s, 350s, 400s, 450s, 500s, 550s, and 600s, such as 450s, or any range of two, such as 350s to 550s.

[0076] According to some embodiments of the present invention, the dosage of spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres during the reaction process is 10 mg / L to 50 mg / L.

[0077] According to some embodiments of the present invention, during the reaction process, the dosage of spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres is any value among 10 mg / L, 15 mg / L, 20 mg / L, 25 mg / L, 30 mg / L, 35 mg / L, 40 mg / L, 45 mg / L, and 50 mg / L, such as 30 mg / L, or any range formed by both, such as 15 mg / L to 45 mg / L.

[0078] According to some embodiments of the present invention, the concentration of the organic micropollutants to be treated during the reaction process is 0.1 mgC / L to 5 mgC / L.

[0079] According to some embodiments of the present invention, during the reaction process, the concentration of the organic micropollutant to be treated is any value among 0.1 mg C / L, 1 mg C / L, 2 mg C / L, 3 mg C / L, 4 mg C / L, and 5 mg C / L, such as 3 mg C / L, or any range formed by both, such as 1 mg C / L to 4 mg C / L. Attached Figure Description

[0080] Figure 1 The XRD characterization results are those of the spin-coordinated MnN3 / CoN4 dual single-atom catalyst prepared in step S3.

[0081] Figure 2 The nitrogen adsorption-desorption curves are those of the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1.

[0082] Figure 3 This is a microscopic morphology image of the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1.

[0083] Figure 4 This is the degradation curve of benzotriazole.

[0084] Figure 5 This is the degradation curve of 4-nitrophenol.

[0085] Figure 6 This is the degradation curve of p-hydroxybenzoic acid.

[0086] Figure 7 It is the effect of nitrobenzene degradation.

[0087] Figure 8 This is the degradation curve of aquaculture wastewater in industrial wastewater. Detailed Implementation

[0088] This invention provides a spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microsphere, comprising a silicate-based spherical support and a spin-coordinated MnN3 / CoN4 dual single-atom catalyst supported on the surface of the silicate-based spherical support, wherein the loading amount of the spin-coordinated MnN3 / CoN4 dual single atoms is 0.1 mg / g to 5.0 mg / g.

[0089] This invention aims to address the increasingly severe problem of recalcitrant micropollutants in conventional water treatment processes. It designs a spin-coordinated MnN3 / CoN4 dual-single-atom ozone catalytic microsphere and applies it to the field of ozone catalytic oxidation, achieving rapid removal of recalcitrant micropollutants in a short time. This spin-coordinated MnN3 / CoN4 dual-single-atom ozone catalytic microsphere features a large number of spin-coordinated MnN3 / CoN4 dual-single-atom sites anchored on the surface of a carrier with a huge specific surface area. These active sites enable rapid ozone catalysis, generating highly oxidizing active species such as surface atomic oxygen. The Mn-Co dual-atom sites can effectively bond and interact electronically with the active terminal oxygen atoms in the ozone molecule. Furthermore, the spin-coordinated electronic regulation of the catalytic interface further enhances the electronic interaction between the Mn-Co dual atoms and ozone, enabling ozone to be converted into active species with almost 100% catalytic decomposition efficiency. The generated active species, due to their extremely high oxidizing activity, rapidly degrade recalcitrant micropollutants in the water, ensuring the quality of the effluent.

[0090] This invention reveals that when treating water rich in recalcitrant micropollutants such as 4-nitrophenol and p-hydroxybenzoic acid (5 mg C / L), 100% removal of these pollutants can be achieved in just 300 seconds. For the extremely recalcitrant UV absorber benzotriazole (5 mg C / L) and the chemical intermediate nitrobenzene (5 mg C / L), this technology can achieve nearly 80% removal in just 300 seconds. Compared to traditional ozone oxidation processes, this process improves the removal capacity of benzotriazole, 4-nitrophenol, p-hydroxybenzoic acid, and nitrobenzene by 13.5, 5.6, 5.3, and 5.1 times, respectively. The shorter residence time and high efficiency in pollutant purification give this technology enormous application potential and technological advantages. This invention is applicable to the advanced treatment of drinking water. This invention can be applied after the filtration process in drinking water plants, utilizing a spin-synergistic MnN3 / CoN4 dual-single-atom catalytic ozonation process to effectively remove recalcitrant organic micropollutants from water. Simultaneously, ozone has bactericidal, disinfectant, and algae-removing effects, ensuring the safety of drinking water supply. This invention can also be applied to the advanced treatment and reuse of reclaimed water. It can be applied after the secondary sedimentation process in municipal wastewater treatment, utilizing a spin-synergistic MnN3 / CoN4 dual-single-atom catalytic ozonation process to effectively remove recalcitrant organic micropollutants from water, ensuring the quality of reclaimed water. This invention can also be applied to the efficient treatment and reuse of industrial wastewater, such as high-concentration industrial wastewater from pharmaceuticals, dyeing and printing, aquaculture, and electroplating, which is difficult to treat effectively using biochemical processes. It can be applied after conventional physical pretreatment processes (such as coagulation-sedimentation), using a spin-synergistic MnN3 / CoN4 dual-single-atom catalytic ozonation process to effectively remove recalcitrant organic pollutants from water, reducing the concentration of organic matter in the effluent while improving its biodegradability, achieving the resource-based regeneration of industrial wastewater.

[0091] Regarding the synergistic mechanism of this invention, it should be noted that the two single-atom sites of MnN3 and CoN4 can synergistically co-adsorb with the two terminal oxygen groups of ozone molecules, jointly providing more electrons to ozone molecules, thus promoting the decomposition of 1 mol of ozone into 2 mol of surface oxygen species. The dual surface oxygen species can achieve more efficient oxidative degradation of pollutants.

[0092] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0093] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0094] Unless otherwise specified, "room temperature" in this invention means 25℃±5℃.

[0095] Unless otherwise specified, "about" in this invention means that the allowable error is within ±2%.

[0096] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0097] Example 1 A spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microsphere was prepared, and the specific process is as follows: S1: Prepare a solution of N,N-dimethylformamide containing 160 mM zinc nitrate hexahydrate, 80 mM dimethylimidazole, and 10 mM manganese acetate dihydrate. Allow the solution to react at 25°C for 8 hours. The resulting crystalline substance is then recovered, washed with ethanol, and dried. S2: The obtained solid powder was calcined at 1000℃ for 30 min under an inert gas atmosphere. The powder sample was then etched with sulfuric acid for 2 h at 50℃. Afterwards, it was recovered, washed with deionized water, and dried. S3: The obtained solid powder is subjected to high-temperature calcination in an inert gas atmosphere at a temperature of 900℃ for 90 minutes.

[0098] The calcined sample was uniformly dispersed in a mixed solution containing 20 mM cyanamide and 0.2 mM cobalt chloride, with isopropanol solution (75%) as the solute. It was then recovered, washed with deionized water, and dried. The obtained solid powder was then subjected to high-temperature calcination under an inert gas atmosphere at 1000℃ for 30 min. S4: Silicate powder is mixed with water to form a slurry, which is then granulated to obtain a spherical support. Utilizing the gelation properties of silicate, the spin-coordinated MnN3 / CoN4 dual single-atom catalyst prepared in step S3 is loaded onto the surface of the spherical support. After curing at 40°C for 12 hours, spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres are obtained.

[0099] Figure 1 The XRD characterization results are for the spin-coordinated MnN3 / CoN4 dual single-atom catalyst prepared in step S3. Characteristic diffraction peaks of the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalyst can be observed, directly confirming the successful synthesis of the catalyst and that its crystal structure is consistent with the design expectations.

[0100] Figure 2 This is the nitrogen adsorption-desorption curve of the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1. The curves exhibit typical adsorption characteristics of porous materials. Combined with BET calculations, this confirms that the catalyst possesses a huge specific surface area (up to 1250~1600 m²). 2 / g), which can provide a sufficient reaction platform for ozone catalytic reaction.

[0101] Figure 3 This is a microscopic morphology image of the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1. The microstructure (such as size and dispersion state) of the spin-coordinated MnN3 / CoN4 dual single-atom catalytic microspheres can be clearly observed, intuitively presenting the physical morphological characteristics of the catalyst and providing structural support for its catalytic performance.

[0102] Example 2 Wastewater was treated using the spin-coordinated MnN3 / CoN4 dual-monoatom ozone catalytic microspheres prepared in Example 1. The process was as follows: The spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1 and the micro-pollutants to be treated were added to the ozone contact reactor in sequence. When using a porous aeration device for ozone aeration, thorough stirring is required during the reaction process. After the reaction is complete, the catalyst is recovered from the water by filtration.

[0103] Ozone gas was generated using an ozone generator and aerated using jet aerator heads. The gaseous ozone concentration was 15 mg / L, the ozone gas flow rate was 100 mL / min, the residence time was 300 s, and the catalyst dosage was 50 mg / L.

[0104] The added organic micropollutants to be treated were nitrobenzene, p-hydroxybenzoic acid, 4-nitrophenol, and benzotriazole, all at a concentration of 5 mg C / L.

[0105] Figure 4 This is the degradation curve of benzotriazole. Comparing the degradation rates of ozone oxidation alone and ozone catalytic oxidation, the catalytic group showed a significantly higher degradation efficiency, confirming that this technology has a highly efficient removal capability for benzotriazole, an extremely difficult-to-degrade UV absorber.

[0106] Figure 5 This is the degradation curve of 4-nitrophenol. The degradation rate of 4-nitrophenol in the catalytic oxidation group is much better than that in the ozone oxidation group alone, verifying that the catalyst can enhance ozone decomposition and rapidly degrade this type of recalcitrant organic micropollutant.

[0107] Figure 6 This is the degradation curve of p-hydroxybenzoic acid. The ozone catalytic oxidation system shows a significantly higher removal efficiency for p-hydroxybenzoic acid than ozone oxidation alone, further demonstrating the universal and efficient removal capability of this catalytic process for recalcitrant pollutants with different structures.

[0108] Figure 7 This study investigated the effects of different anions on the degradation of nitrobenzene. The curves showed that even with the interference of multiple anions, the catalytic system maintained a stable and efficient degradation effect on nitrobenzene, confirming that the technology has strong anti-interference capabilities and is suitable for complex water quality scenarios.

[0109] Furthermore, the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1 can also be used for the efficient treatment and reuse of industrial wastewater, such as high-concentration industrial wastewater that is difficult to treat effectively by biochemical processes, including pharmaceutical wastewater, dyeing and printing wastewater, aquaculture wastewater, and electroplating wastewater. Figure 8 As shown, Figure 8 This study targets aquaculture wastewater within industrial wastewater. Compared to ozone oxidation alone, the catalytic oxidation group can reduce the COD concentration of actual wastewater more rapidly, demonstrating that this technology has a truly effective treatment capability for practical, recalcitrant, high-COD industrial wastewater.

[0110] The spin-synergistic MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1 can also be used for advanced treatment and reuse of reclaimed water. They can be applied after the secondary sedimentation process in municipal wastewater treatment processes to effectively remove recalcitrant organic micropollutants in water using the spin-synergistic MnN3 / CoN4 dual single-atom catalytic ozonation process, thus ensuring the quality of reclaimed water reuse.

[0111] Furthermore, the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1 can also be used for the efficient treatment and reuse of industrial wastewater, such as high-concentration industrial wastewater that is difficult to treat effectively by biochemical processes, such as pharmaceutical wastewater, dyeing and printing wastewater, aquaculture wastewater, and electroplating wastewater.

[0112] Furthermore, the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres prepared in Example 1 can be used in conventional physical pretreatment processes (such as coagulation-sedimentation). The spin-coordinated MnN3 / CoN4 dual single-atom catalytic ozonation process can effectively remove recalcitrant organic pollutants from water, reduce the concentration of organic matter in the effluent while improving its biodegradability, and realize the resource-based regeneration of industrial wastewater.

[0113] The present invention has been described in detail above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. Spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres, characterized in that, The catalyst includes a silicate-based spherical support and a spin-coordinated MnN3 / CoN4 dual single-atom catalyst supported on the surface of the silicate-based spherical support, wherein the loading of the spin-coordinated MnN3 / CoN4 dual single atoms is 0.1 mg / g to 5.0 mg / g.

2. The spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres according to claim 1, characterized in that, The specific surface area of ​​the spin-coordinated MnN3 / CoN4 dual single-atom catalyst is 1250 m². 2 / g~1600m 2 / g; and / or, the diameter of the silicate-based spherical carrier is 0.1cm to 5.0cm.

3. A method for preparing spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres as described in claim 1 or 2, characterized in that, Includes the following steps: S1: Prepare an N,N-dimethylformamide solution containing zinc nitrate hexahydrate, dimethylimidazole and manganese acetate dihydrate, allow it to stand for reaction, and then recover the generated crystalline substance. S2: The crystalline material is subjected to a first calcination treatment under a protective gas atmosphere to obtain a powder sample, the powder sample is acid etched, and then the powder sample is recovered. S3: The obtained solid powder is subjected to a second calcination treatment under a protective gas atmosphere. The calcined sample is dispersed in a mixed solution containing cyanamide, cobalt chloride and isopropanol. The powder sample is then recovered and subjected to a third calcination under a protective gas atmosphere to obtain the spin-coordinated MnN3 / CoN4 dual single-atom catalyst. S4: Silicate powder is mixed with water to form a slurry, which is then granulated to obtain a spherical support. Utilizing the gelation properties of silicate, the spin-coordinated MnN3 / CoN4 dual single-atom catalyst is self-assembled onto the surface of the spherical support. After curing, the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres are obtained.

4. The method according to claim 3, characterized in that, In step S1, the concentration of zinc nitrate hexahydrate is 80 mmol / L to 160 mmol / L; and / or, the concentration of dimethylimidazole in step S1 is 40 mmol / L to 80 mmol / L; and / or, the concentration of manganese acetate dihydrate in step S1 is 4 mmol / L to 10 mmol / L; and / or, in step S1, the reaction time is 8 to 24 h; and / or, in step S1, the reaction temperature is 25 to 120 °C.

5. The method according to claim 3, characterized in that, In step S2, the temperature of the first calcination treatment is 1000~1200℃; and / or, the time of the first calcination treatment in step S2 is 30~90min; and / or, the time of the acid etching treatment in step S2 is 2~5h; and / or, the temperature of the acid etching treatment in step S2 is 50~80℃.

6. The method according to claim 3, characterized in that, In step S3, the temperature of the second calcination treatment is 900~1200℃; and / or, the time of the second calcination treatment in step S3 is 90~180min; the temperature of the third calcination treatment in step S3 is 1000~1200℃; and / or, the time of the third calcination treatment in step S3 is 30~90min.

7. The method according to claim 3, characterized in that, In step S3, the concentration of cyanamide in the mixed solution is 20 mmol / L to 40 mmol / L; and / or, in step S3, the concentration of cobalt chloride in the mixed solution is 0.2 mmol / L to 1.0 mmol / L; and / or, in step S3, the concentration of isopropanol in the mixed solution is 25% to 75%.

8. The method according to claim 3, characterized in that, In step S4, the curing temperature is 20~60℃; and / or the curing time is 6~24h.

9. A wastewater treatment method, characterized in that, The wastewater treatment method includes adding the spin-coordinated MnN3 / CoN4 dual single-atom ozone catalytic microspheres as described in claim 1 or 2 and the wastewater to be treated into an ozone contact reactor for reaction, and then recovering the catalyst from the water by filtration after the reaction.

10. The wastewater treatment method according to claim 9, characterized in that, During the reaction, aeration is performed using jet injectors, aeration plates, or aeration heads; and / or, during the reaction, the gas phase ozone concentration is 0.01~15 mg / L, and the ozone gas flow rate is 100 mL / min~400 mL / min; and / or, during the reaction, the residence time is 300 s~600 s; and / or, during the reaction, the dosage of spin-coordinated MnN3 / CoN4 dual monoatomic ozone catalytic microspheres is 10 mg / L~50 mg / L; and / or, during the reaction, the concentration of organic micropollutants to be treated is 0.1 mgC / L~5 mgC / L.

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