Thermal confinement hollow porous carbon nanosphere for removing organic matters in water as well as preparation method and application of thermal confinement hollow porous carbon nanosphere

Abstract

The invention discloses a thermal confinement hollow porous carbon nanosphere for removing organic matters in water as well as a preparation method and application of the thermal confinement hollow porous carbon nanosphere, and belongs to the technical field of environmental science and engineering. The preparation method comprises the following steps: mixing a fluorine source and an organic solvent in ultrapure water, stirring to form a mixed solution, and mixing and stirring the mixed solution, a silicon source and dopamine hydrochloride to obtain a turbid liquid; sequentially centrifuging, washing and freeze-drying the turbid liquid to obtain SiO2 (at) PDA powder; and sequentially carrying out high-temperature pyrolysis and acid pickling on the SiO2 (at) PDA powder to obtain the thermal confinement hollow porous carbon nanospheres. Tetraethoxysilane with good hydrolyzability is used as a silicon source, ammonium fluoride is used as a fluorine source to etch the tetraethoxysilane to obtain a silicon oxide structure, then the silicon oxide structure is crosslinked with dopamine hydrochloride to form SiO2 (at) PDA with a core-shell structure, and finally high-temperature pyrolysis and acid pickling are performed to obtain the thermal confinement hollow porous carbon nanospheres.

Description

Technical Field

[0001] The present invention belongs to the field of environmental science and engineering technology, and relates to water treatment technology and catalyst development, and specifically relates to a thermally confined hollow porous carbon nanosphere for removing organic matter from water, and a preparation method and application thereof. Background Art

[0002] With the acceleration of the global industrialization process, water pollution has become increasingly serious and has become an important issue affecting human health and the ecological environment. There are many types of pollutants in water bodies, including heavy metal ions, pesticides, drug residues, dyes and organic matter. These pollutants not only threaten aquatic organisms, but also pose challenges to drinking water safety and sustainable use of water resources. Therefore, it is particularly important to develop efficient and economical water treatment technologies. Among many water treatment materials, porous carbon nanospheres have gradually become a research hotspot due to their excellent physical and chemical properties and broad application prospects.

[0003] Porous carbon nanospheres (PCS) refer to carbon materials with porous structures and spherical morphology synthesized by specific methods. Their main characteristics include: (1) High specific surface area: Porous carbon nanospheres usually have a large specific surface area, which makes them exhibit excellent performance in adsorption and catalytic reactions. The increase in specific surface area can provide more reaction sites and increase the probability of contact with pollutants. (2) Good pore structure: The pore size distribution of porous carbon nanospheres can be adjusted to meet the removal needs of different types of pollutants. Its pore structure is usually composed of micropores, mesopores and macropores, which can effectively capture various pollutants. (3) Chemical stability: Porous carbon nanospheres show good stability in various chemical environments, are not easily degraded or corroded, and are suitable for long-term use. (4) Adjustability and functionalization: By changing the synthesis conditions and methods, the structure and surface properties of porous carbon nanospheres can be adjusted to further enhance their removal ability for specific pollutants. There are many methods for preparing porous carbon nanospheres, mainly including the following: (1) Template method: Use template materials such as silica and polystyrene to first prepare carbon-based composites, and then remove the template through heat treatment to obtain porous carbon nanospheres. (2) Self-assembly method: Use the self-assembly properties of polymers, surfactants and other substances to synthesize carbon materials with porous structures. (3) Sol-gel method: Form gel through chemical reaction, then dry and heat treat to obtain porous carbon nanospheres. (4) Hydrothermal method: Under high temperature and high pressure conditions, organic precursors are converted into porous carbon materials, which has high reaction efficiency and good material uniformity.

[0004] Patent CN105498821A discloses a composite material for catalytic degradation of nitrogen oxides, its preparation method and use. The invention improves the photocatalytic performance by regulating the microstructure of g-C3N4 and heterogeneously connecting with other materials. The hollow spherical morphology of g-C3N4 can optimize the absorption and distribution of visible light, thereby improving the photocatalytic efficiency. In addition, graphene-like planar two-dimensional materials have good electrical conductivity, and compounding them with g-C3N4 can promote the transfer and separation of charges during the photocatalytic process. In practical applications, photocatalysts usually require a suitable carrier. Polymer nanofibers prepared by electrospinning can effectively fix nanoparticles, thereby preparing a composite material for catalytic degradation of nitrogen oxides (especially nitric oxide).

[0005] Patent CN111410287A discloses a treatment method for organic pollutants and hexavalent chromium by using nano-carbon materials for synergistic oxidation. The invention uses the conditions under which organic pollutants and hexavalent chromium exist simultaneously, adds nano-carbon materials, and adjusts the pH value to 1-2. Organic pollutants and hexavalent chromium undergo redox reactions, and after the reaction is completed, organic pollutants and hexavalent chromium are removed simultaneously. The method of the present invention uses cheap and environmentally friendly nano-carbon materials as catalysts to induce synergistic oxidation and reduction of organic pollutants and hexavalent chromium in water, and can achieve the final removal of toxic organic pollutants and highly toxic hexavalent chromium in water.

[0006] Patent CN115677014A discloses a method for degrading emerging pollutants in water by activating isocyanurate with nanocarbon materials. The invention first provides a composition, which is composed of isocyanurate and nanocarbon materials stored separately, and then provides a method for degrading emerging pollutants in water with the composition: adding isocyanurate and nanocarbon materials to a water body containing pollutants, the isocyanurate is activated by the nanocarbon material, singlet oxygen is generated, and the pollutants are degraded. Although the above carbon nanomaterials used in water treatment have good water treatment performance, they do not have wide adaptability.

[0007] In the current water treatment technology field, there are many products and methods on the market for the removal of organic pollutants. However, due to some significant deficiencies and disadvantages, their application effect and wide range are limited: (1) Low catalytic efficiency: Traditional catalysts are often inefficient in activating peroxides (such as peracetic acid, hydrogen peroxide, etc.). Most catalytic reactions need to be carried out at higher temperatures, which not only prolongs the reaction time but also reduces the treatment efficiency. For example, some common catalysts usually take several hours to achieve an acceptable removal rate when removing organic matter such as antibiotics, which cannot meet the rapid reaction requirements in industrial applications. The root cause of this low efficiency is the insufficient thermal conductivity and reaction activity of existing catalysts. (2) High energy consumption: Existing catalytic systems usually consume a lot of thermal energy. Since the heat in the reaction is mainly used to heat the solution rather than activate the reactants, the overall energy consumption increases. For example, when using traditional thermal catalysts, energy waste is very serious, which not only increases operating costs but also has adverse effects on the environment. The lack of an effective energy utilization mechanism makes the existing water treatment technologies on the market inadequate in terms of economy and sustainability. (3) Defects dominated by free radical reactions: Many catalytic systems rely mainly on free radical reaction pathways. Although this reaction pathway is effective in removing organic matter, it has poor selectivity and may lead to the generation of secondary pollutants or harmful byproducts. In addition, the generation and consumption of free radicals are often unstable, which may cause unpredictable environmental impacts during water treatment. For example, when using traditional hydrogen peroxide treatment, although it can effectively degrade organic pollutants, it may introduce new harmful substances, thereby affecting water quality safety. (3) Poor catalyst stability: Many existing catalysts are prone to lose activity during the reaction process or suffer poisoning due to interference from reactants. For example, some metal catalysts may be covered by pollutants during long-term reactions, resulting in a significant decrease in catalytic activity. Such defects increase the frequency of catalyst replacement and maintenance costs, reducing their practical application value. (4) Insufficient environmental adaptability: Existing catalysts have poor adaptability under different water quality conditions (such as pH value, ionic strength, temperature, etc.), which limits their application. Many catalysts perform well under specific conditions, but may fail in actual sewage treatment due to changes in water quality. This lack of adaptability requires customers to take additional water quality factors into consideration when using these products, increasing the complexity of operations.

[0008] Therefore, it is of great significance to design a thermally confined hollow porous carbon nanosphere (HPCS) that can improve degradation efficiency, reduce energy consumption, improve reaction selectivity and enhance stability. Summary of the invention

[0009] In view of the shortcomings of the prior art, the present invention uses tetraethoxysilane with good hydrolysis as a silicon source, and uses ammonium fluoride as a fluorine source to etch tetraethoxysilane to obtain a silicon oxide structure, which is then cross-linked with dopamine hydrochloride to form SiO2@PDA with a core-shell structure, and then subjected to high-temperature pyrolysis to obtain thermally confined hollow porous carbon nanospheres. Specifically, the technical solution of the present invention includes the following contents: One of the purposes of the present invention is to provide a method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, the preparation method comprising the following steps: The fluorine source and the organic solvent are mixed in ultrapure water and stirred to form a mixed solution, and the mixed solution is mixed with a silicon source and dopamine hydrochloride and stirred to obtain a suspension; The suspension is centrifuged, washed and freeze-dried in sequence to obtain SiO2@PDA powder; The SiO2@PDA powder is successively subjected to high-temperature pyrolysis and acid washing to obtain the thermally confined hollow porous carbon nanospheres.

[0010] Furthermore, the fluorine source is ammonium fluoride, and the fluorine source is used to promote the formation of a thermally confined hollow porous carbon nanosphere structure.

[0011] Furthermore, the silicon source is tetraethoxysilane, and the silicon source serves as a hard template for the thermally confined hollow porous carbon nanospheres.

[0012] Furthermore, the organic solvent is anhydrous ethanol.

[0013] Furthermore, the volume ratio of the fluorine source: the organic solvent: the silicon source is 1:19:1.5.

[0014] Furthermore, the amount of dopamine hydrochloride added is 0.4 g of dopamine hydrochloride per milliliter of fluorine source, and the dopamine hydrochloride is used to improve the stability and activity of the thermally confined hollow porous carbon nanospheres.

[0015] Furthermore, the high temperature pyrolysis conditions include a pyrolysis temperature of 600° C. to 1100° C. and a pyrolysis time of 1 hour.

[0016] Preferably, the high temperature pyrolysis conditions are pyrolysis temperature 1000°C and pyrolysis time 1h Furthermore, the acid reagent for pickling is a hydrofluoric acid solution with a mass concentration of 10%.

[0017] The second purpose of the present invention is to provide a thermally confined hollow porous carbon nanosphere for removing organic matter from water.

[0018] The third purpose of the present invention is to provide an application of thermally confined hollow porous carbon nanospheres for removing organic matter from water in the field of catalytic removal of organic matter from water, wherein the reaction system for catalytic removal of organic matter is composed of thermally confined hollow porous carbon nanospheres, peroxides and organic pollutants.

[0019] Furthermore, the peroxide is peracetic acid.

[0020] Furthermore, the usage amount of the thermally confined hollow porous carbon nanospheres is 6 mg of thermally confined hollow porous carbon nanospheres per milliliter of organic pollutants.

[0021] Furthermore, the usage amount of the peroxide is 226.32 μmol of peroxide per liter of organic pollutant.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The thermally confined hollow porous carbon nanospheres (HPCS) obtained by the present invention can generate local high temperatures in their internal space through the thermal sealing effect, significantly improving the activation efficiency of peracetic acid (PAA). Experimental results show that in the dual catalytic reaction system of HPCS combined with peracetic acid, the degradation efficiency of sulfadiazine (SDZ) exceeds 99%, which is significantly improved compared with the treatment efficiency of other catalysts. This improvement makes it possible to achieve efficient removal of organic pollutants in a shorter time.

[0023] (2) Since the thermally confined hollow porous carbon nanospheres (HPCS) obtained by the present invention can effectively utilize the photothermal effect, reduce the waste of heat energy, and make the use of energy in the catalytic process more efficient. Compared with the high energy consumption mode commonly seen in the prior art, the present invention effectively reduces the overall energy consumption through the generation and utilization of local heat, thereby improving economy and sustainability.

[0024] (3) The thermally confined hollow porous carbon nanospheres (HPCS) obtained by the present invention introduce a non-radical reaction pathway in the catalytic reaction process of removing organic pollutants from water, reducing the possibility of generating harmful byproducts. This improvement in reaction selectivity enhances the safety of water treatment and reduces potential risks to the ecological environment.

[0025] (4) The thermally confined hollow porous carbon nanospheres (HPCS) obtained by the present invention maintain good catalytic activity in long-term use, reducing the risk of catalyst deactivation. Compared with existing catalysts, HPCS has higher regeneration and better pollution resistance, extending the service life of the catalyst and reducing maintenance and replacement costs.

[0026] (5) The thermally confined hollow porous carbon nanospheres (HPCS) obtained by the present invention exhibit good catalytic performance under different water quality conditions, demonstrating its adaptability in various practical application scenarios. This feature enables HPCS to be widely used in different types of sewage treatment to meet diverse market needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the TEM image of HPCS-1000℃ prepared in Example 5 of the present invention.

[0028] Figure 2 This is the TEM image of PCS-1000℃ prepared in Comparative Example 1.

[0029] Figure 3 HAADF images and selected area electron diffraction (SAED) patterns of HPCS-1000°C obtained in Example 5 of the present invention and PCS-1000°C obtained in Comparative Example 1.

[0030] Figure 4 This is the element mapping diagram of HPCS-1000℃ obtained in Example 5 of the present invention.

[0031] Figure 5 This is the EDS energy spectrum of HPCS-1000°C obtained in Example 5 of the present invention.

[0032] Figure 6 This is the element mapping diagram of PCS-1000℃ obtained in Comparative Example 1.

[0033] Figure 7 This is the EDS spectrum of PCS-1000℃ obtained in Comparative Example 1.

[0034] Figure 8 It is a line graph of the thermal confinement distribution of the thermally confined hollow porous carbon nanospheres (HPCS) obtained in Examples 1 to 6.

[0035] Fig. 9 This is a graph showing the degradation performance of HPCS-1000°C for different types of antibiotics obtained in Example 5 of the present invention.

[0036] Fig.10 This is a graph showing the degradation performance of sulfadiazine by HPCS-1000°C obtained in Example 5 of the present invention after being used continuously for 3 times.

[0037] Fig.11 This is the degradation performance diagram of sulfadiazine under different catalytic reaction systems.

[0038] Fig.12 This is the kinetic rate diagram of sulfadiazine degradation under different catalytic reaction systems. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below through the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0040] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0041] Example 1: A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 min to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 min. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 h to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 h to obtain dry SiO2@PDA powder. The SiO2@PDA powder was placed in a reactor in a nitrogen atmosphere and heated to 600°C at a heating rate of 5°C / min for pyrolysis treatment for 1 h. After the pyrolysis, the mixture was naturally cooled to room temperature, and the pyrolyzed SiO2@PDA powder was washed with a 10% hydrofluoric acid solution (prepared by mixing 1 mL hydrofluoric acid + 9 mL deionized water), then washed with deionized water until neutral and freeze-dried to obtain thermally confined hollow porous carbon nanospheres, which were recorded as HPCS-600℃.

[0042] Example 2: A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 min to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 min. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 h to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 h to obtain dry SiO2@PDA powder. The SiO2@PDA powder was placed in a reactor in a nitrogen atmosphere and heated to 700 °C at a heating rate of 5 °C / min for pyrolysis treatment for 1 h. After the pyrolysis, the mixture was naturally cooled to room temperature, and the pyrolyzed SiO2@PDA powder was washed with a 10% hydrofluoric acid solution (prepared by mixing 1 mL hydrofluoric acid + 9 mL deionized water), then washed with deionized water until neutral and freeze-dried to obtain thermally confined hollow porous carbon nanospheres, which were recorded as HPCS-700℃.

[0043] Example 3: A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 min to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 min. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 h to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 h to obtain dry SiO2@PDA powder. The SiO2@PDA powder was placed in a reactor in a nitrogen atmosphere and heated to 800°C at a heating rate of 5°C / min for pyrolysis treatment for 1 h. After the pyrolysis was completed, the mixture was naturally cooled to room temperature, and the pyrolyzed SiO2@PDA powder was washed with a 10% hydrofluoric acid solution (prepared by mixing 1 mL hydrofluoric acid + 9 mL deionized water), then washed with deionized water until neutral and freeze-dried to obtain thermally confined hollow porous carbon nanospheres, which were recorded as HPCS-800℃.

[0044] Example 4: A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 min to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 min. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 h to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 h to obtain a dry precursor powder. The precursor powder was placed in a reactor in a nitrogen atmosphere and heated to 900 °C at a heating rate of 5 °C / min for pyrolysis treatment for 1 h. After the pyrolysis, the mixture was naturally cooled to room temperature, and the pyrolyzed SiO2@PDA powder was washed with a 10% hydrofluoric acid solution (prepared by mixing 1 mL hydrofluoric acid + 9 mL deionized water), then washed with deionized water until neutral and freeze-dried to obtain thermally confined hollow porous carbon nanospheres, which were recorded as HPCS-900℃.

[0045] Example 5: A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 min to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 min. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 h to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 h to obtain a dry precursor powder. The precursor powder was placed in a reactor in a nitrogen atmosphere and heated to 1000 ° C at a heating rate of 5 ° C / min for pyrolysis treatment for 1 h. After the pyrolysis, the mixture was naturally cooled to room temperature, and the pyrolyzed SiO2@PDA powder was washed with a 10% hydrofluoric acid solution (prepared by mixing 1 mL hydrofluoric acid + 9 mL deionized water), then washed with deionized water until neutral and freeze-dried to obtain thermally confined hollow porous carbon nanospheres, which were recorded as HPCS-1000℃.

[0046] Example 6: A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was measured and placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 minutes to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 minutes. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 hours to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 hours to obtain a dry precursor powder. The precursor powder was placed in a reactor in a nitrogen atmosphere and heated to 1100°C at a heating rate of 5°C / min for pyrolysis treatment for 1 hour. After the pyrolysis, the mixture was naturally cooled to room temperature, and the pyrolyzed SiO2@PDA powder was washed with a 10% hydrofluoric acid solution (prepared by mixing 1 mL hydrofluoric acid + 9 mL deionized water), then washed with deionized water until neutral and freeze-dried to obtain thermally confined hollow porous carbon nanospheres, which were recorded as HPCS-1100℃.

[0047] Comparative Example 1: A method for preparing non-thermally confined hollow porous carbon nanospheres for removing organic matter from water, specifically comprising the following steps: 80 mL of ultrapure water was measured and placed in a container, and then 1.0 mL of ammonium fluoride solution and 19 mL of anhydrous ethanol were added and stirred for 30 min to obtain a mixed solution. 1.5 mL of tetraethoxysilane was added dropwise to the mixed solution and stirred continuously for 15 min. After the stirring was completed, 0.4 g of dopamine hydrochloride was added and stirred at room temperature for 24 h to obtain a suspension containing the black precursor SiO2@PDA. The suspension was centrifuged at a speed of 10000 r / min to obtain the black precursor SiO2@PDA, and then washed with deionized water, and then placed in a freeze dryer for freeze drying for 48 h to obtain a dry precursor powder. The precursor powder was placed in a reactor in a nitrogen atmosphere, heated to 1000 ° C at a heating rate of 5 ° C / min, and pyrolyzed for 1 h, recorded as PCS-1000 ° C.

[0048] The TEM images of HPCS-1000℃ obtained in Example 5 and PCS-1000℃ obtained in Comparative Example 1 were measured. Figure 1 and Figure 2 ,from Figure 1 and Figure 2 It can be seen that both HPCS-1000℃ and PCS-1000℃ have spherical structures with an average diameter of about 300nm. Scanning electron microscopy shows that there are more mesoporous structures in HPCS-1000℃ than in PCS-1000℃. More mesoporous structures are conducive to the entry and exit of reactants and products into the material.

[0049] The HAADF images and selected area electron diffraction (SAED) patterns of the HPCS-1000°C obtained in Example 5 and the PCS-1000°C obtained in Comparative Example 1 are shown in Table 1. Figure 3 ,from Figure 3 It can be seen that both have an amorphous structure.

[0050] The elemental mapping and EDS spectrum of HPCS-1000°C obtained in Example 5 are shown in Figure 4 and Figure 5 , the PCS-1000℃ elemental mapping and EDS spectrum obtained in Comparative Example 1 were measured, and the results are shown in Figure 6 and Figure 7 ,Depend on Figure 4 and Figure 6 It can be seen that C, O, N and Si elements are evenly distributed in HPCS-1000℃ and PCS-1000℃; Figure 5 and Figure 7 It can be seen that compared with PCS-1000℃, the Si element in HPCS-1000℃ is significantly reduced, indicating that Si is effectively removed.

[0051] The specific surface area of ​​HPCS-1000℃ after removing Si element was measured by BET method (gas adsorption method) to be 683.3m 2 / g, much higher than 125.0 m / g of PCS-1000℃ 2 / g. The higher specific surface area exposes more active sites, which is beneficial to the activation of PAA.

[0052] The thermal confinement of the thermally confined hollow porous carbon nanospheres (HPCS) obtained in Examples 1 to 6 was measured, and the results are shown in Figure 8 ,From the results in the figure, it can be seen that by heating the solution, the heating temperature is locked in the thermally confined hollow porous carbon nanosphere (HPCS) material, achieving a better activation effect.

[0053] Application Example 1: The application of thermally confined hollow porous carbon nanospheres in the field of catalytic removal of organic matter in water specifically includes the following processes: 300 mg of the thermally confined hollow porous carbon nanospheres (HPCS) prepared in Example 5 were mixed with 50 mL of sulfadiazine (SDZ) solution (mass concentration of 1 mg / L) and stirred for 10 min to reach adsorption equilibrium.

[0054] Then, peracetic acid (PAA) was slowly added to the mixed system in adsorption equilibrium. The amount of peracetic acid added was controlled to be 226.32 μmol per liter of sulfadiazine. A 500W xenon lamp was used for illumination to make the internal temperature of the thermally confined hollow porous carbon nanospheres (HPCS) significantly higher than the surrounding solution temperature.

[0055] Application Example 2: The application of thermally confined hollow porous carbon nanospheres in the field of catalytic removal of organic matter in water specifically includes the following processes: Sulfadiazine (SDZ) in Application Example 1 was replaced by chlortetracycline (CTC), and the other conditions remained the same as those in Application Example 1.

[0056] Application Example 3: The application of thermally confined hollow porous carbon nanospheres in the field of catalytic removal of organic matter in water specifically includes the following processes: Sulfadiazine (SDZ) in Application Example 1 was replaced by doxorubicin (DOX), and the other conditions remained the same as those in Application Example 1.

[0057] Application example 4: The application of thermally confined hollow porous carbon nanospheres in the field of catalytic removal of organic matter in water specifically includes the following processes: Sulfadiazine (SDZ) in Application Example 1 was replaced by imipenem (IPM), and the other conditions remained the same as those in Application Example 1.

[0058] Determination of the degradation performance of different types of antibiotics in application examples 1 to 4. The results are shown in Fig. 9 ,pass Fig. 9 It can be found that the thermally confined hollow porous carbon nanospheres (HPCS) prepared by the present invention have good applicability to different organic pollutants.

[0059] The thermally confined hollow porous carbon nanospheres (HPCS) obtained by filtration in Application Example 1 were filtered and recovered, and recycled twice according to the reaction system of Application Example 1, for a total of three times. The HPCS recovered by the last filtration was calcined at 1000°C for 1 hour, and then the degradation performance of sulfadiazine (SDZ) was determined according to the reaction system of Application Example 1. The results are shown in Fig.10 ,pass Fig.10 It can be found that the thermally confined hollow porous carbon nanospheres (HPCS) prepared at a pyrolysis temperature of 1000°C in the present invention, after being recycled 3 times and calcined at a high temperature of 1000°C, the performance of degrading sulfadiazine is restored, and it still has good degradation performance for organic matter, indicating that the thermally confined hollow porous carbon nanospheres (HPCS) of the present invention have good recycling performance, save the production cost of materials, and have economic benefits.

[0060] Comparison of reaction systems with different catalysis: The thermally confined hollow porous carbon nanospheres (HPCS-1000℃) + peracetic acid (PAA) system in Application Example 1 was replaced with PCS-1000℃ single catalytic system, HPCS-1000℃ single catalytic system, peracetic acid (PAA) single catalytic system, PCS-1000℃ + peracetic acid (PAA) dual catalytic system, PCS-1000℃ + peracetic acid (PAA) dual catalytic system in dark environment and HPCS-1000℃ + peracetic acid (PAA) dual catalytic system in dark environment, and then the degradation performance and kinetic rate constant of sulfadiazine (SDZ) were determined. The results are shown in Table 1. Fig.11 and Fig.12 .

[0061] pass Fig.11 You can get: (1) The single catalytic system of peracetic acid (PAA) can be directly activated under xenon lamp irradiation, and 32.6% of SDZ is degraded after 90 minutes.

[0062] (2) After 90 minutes, the removal rate of SDZ by the HPCS-1000℃ single catalytic system under xenon lamp irradiation was 25.7%.

[0063] (3) The removal rate of SDZ by PCS-1000℃ single catalytic system under xenon lamp irradiation was 19.6%.

[0064] (4) The dual catalytic system of HPCS-1000℃+peracetic acid (PAA) in dark environment can also activate PAA in the dark, and 34.4% of SDZ is degraded after 90 minutes.

[0065] (5) PCS-1000℃+PAA dual catalytic system, the removal rate of SDZ under xenon lamp irradiation reached about 98%.

[0066] (6) Under xenon lamp irradiation, the degradation and removal rate of SDZ by the HPCS-1000℃+PAA dual catalytic system reached over 99% after 90 minutes.

[0067] pass Fig.12 You can get: The kinetic rate constant of the HPCS-1000℃+PAA dual catalytic system (4.8×10 -2 / min) is 1.5 times that of the PCS+PAA system.

[0068] The above results further prove that thermally driven nanoconfinement accelerates the degradation of SDZ. 2 The more structures and π bands, the more favorable it is for photothermal conversion. Therefore, HPCS-1000℃ with a highly graphitized structure improves the photothermal conversion performance and promotes the activation of PAA and the degradation of SDZ.

[0069] The above-described embodiments provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected.

Claims

1. A method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water, characterized in that: The preparation method comprises the following steps: The fluorine source and anhydrous ethanol are mixed in ultrapure water and stirred to form a mixed solution, and the mixed solution is mixed with a silicon source and dopamine hydrochloride and stirred to obtain a suspension; The suspension is centrifuged, washed and freeze-dried in sequence to obtain SiO2@PDA powder; The SiO2@PDA powder is successively subjected to high-temperature pyrolysis and acid washing to obtain the thermally confined hollow porous carbon nanospheres.

2. The method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to claim 1, characterized in that: The fluorine source is ammonium fluoride.

3. The method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to claim 1, characterized in that: The silicon source is tetraethoxysilane.

4. The method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to claim 1, characterized in that: The volume ratio of the fluorine source: anhydrous ethanol: silicon source is 1:19:1.

5.

5. The method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to claim 1, characterized in that: The amount of dopamine hydrochloride added is 0.4 g of dopamine hydrochloride per milliliter of fluoride source.

6. The method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to claim 1, characterized in that: The high temperature pyrolysis conditions include a pyrolysis temperature of 600° C. to 1100° C. and a pyrolysis time of 1 hour.

7. The method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to claim 1, characterized in that: The acid reagent for pickling is a hydrofluoric acid solution with a mass concentration of 10%.

8. Thermally confined hollow porous carbon nanospheres prepared by the method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water according to any one of claims 1 to 7.

9. An application of the thermally confined hollow porous carbon nanospheres prepared by the method for preparing thermally confined hollow porous carbon nanospheres for removing organic matter from water as claimed in any one of claims 1 to 7 or the thermally confined hollow porous carbon nanospheres as claimed in claim 8 in the field of catalytic removal of organic matter from water, characterized in that: The reaction system for catalytic removal of organic matter is composed of thermally confined hollow porous carbon nanospheres, peroxides and organic pollutants.

10. The use according to claim 9, characterized in that: The peroxide is peracetic acid.

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