Preparation method and application of oxygen-vacancy-enriched ferrocobalt spinel and carbon core-shell microreactor

Abstract

The invention belongs to the technical field of environmental functional materials, and discloses a preparation method and application of an oxygen-vacancy-enriched ferrocobalt spinel and carbon core-shell microreactor. According to the method, a cobalt-iron spinel and carbon core-shell catalyst with rich oxygen vacancies is constructed through a defect engineering and morphology engineering synergistic strategy, and peroxymonosulfate (PMS) is efficiently activated to degrade antibiotics in water. The method specifically comprises the following steps: synthesizing a ferrocobalt spinel-carbon core-shell structure by adopting hydrothermal, metal ion adsorption and pyrolysis processes, and introducing oxygen vacancies through KBH4 reduction to optimize electron transfer and catalytic activity of the ferrocobalt spinel-carbon core-shell structure. The carbon nucleus in the obtained catalyst effectively enriches pollutants and PMS, and the confinement effect shortens the migration path of active oxygen species; and the PMS activation efficiency is obviously improved by the introduced oxygen vacancies. The catalyst is efficient when used for degrading antibiotics such as ciprofloxacin, has the advantages of high reaction rate constant, high removal rate, wide pH adaptability, strong anti-interference capability, low metal leaching and the like, and has a wide application prospect in the field of environmental governance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of environmental functional materials, and particularly relates to a preparation method of a spinel transition metal oxide catalyst (O V -CFO@C) with an oxygen vacancy-rich core-shell structure, and application of the material in activated degradation of antibiotic pollutants by persulfate. BACKGROUND

[0002] Antibiotics such as CIP in water bodies are difficult to degrade due to chemical inertness, and traditional catalytic technologies have problems such as low active site density, poor mass transfer efficiency, and metal leaching. Although the persulfate (PMS) advanced oxidation process can effectively degrade, existing catalysts (such as metal oxides) have limitations in kinetic performance and other aspects.

[0003] The spinel transition metal oxide (such as CoFe2O4) is inefficient due to mass transfer limitations (Example 3 shows that the degradation rate of CoFe2O4 alone is only 52.71%). The oxygen vacancy (O V ) engineering can enhance catalytic activity, but traditional powder catalysts are prone to agglomeration, and existing research has not revealed the synergistic mechanism of the carbon carrier and O V (Comparative data show that the degradation rate of CFO@C-500 without O V is 80.04%, and the degradation rate is improved to 97.65% after the introduction of O V ). SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to solve the problems of traditional spinel catalysts such as insufficient exposure of active sites, low mass transfer efficiency, poor cycle stability, and risk of metal ion leaching. The present application provides a preparation method of an oxygen vacancy-rich cobalt-iron spinel@carbon core-shell microreactor.

[0005] Another purpose of the present application is to provide the application of the above-mentioned oxygen vacancy-rich cobalt-iron spinel@carbon core-shell microreactor in activating PMS to degrade antibiotics in water.

[0006] The technical solution adopted by the present application is as follows:

[0007] A preparation method of an oxygen vacancy-rich cobalt-iron spinel@carbon core-shell microreactor, the method comprising the following steps:

[0008] I. Preparation of hydrothermal carbon spheres:

[0009] The glucose aqueous solution is transferred to a polytetrafluoroethylene high-pressure reaction kettle, and placed in an oven for hydrothermal reaction. Then the obtained hydrothermal carbon spheres are washed with ethanol-ultra-pure water, separated by suction filtration, and dried in an oven for standby use.

[0010] The concentration of the aqueous glucose solution in step one is 0.04-0.2 g / mL;

[0011] The pyrolysis temperature in step one is 180-220 ℃;

[0012] The pyrolysis time in step one is 4-8 h.

[0013] II. Preparation of cobalt-iron spinel@carbon core-shell microreactor

[0014] The hydrothermal carbon spheres are dispersed in 50 mL of water containing 0.5 M Co(NO3)2·6H2O and 1 M Fe(NO3)3·9H2O (Fe 3+ / Co 2+ Molar ratio = 2:1), and magnetic stirring is performed for a period of time to achieve metal ion adsorption. Subsequently, the metal ion-loaded hydrothermal carbon spheres are separated by vacuum filtration and freeze-dried. The freeze-dried metal ion-loaded hydrothermal carbon spheres are placed in a tube furnace, and pyrolysis calcination is performed under N2 protection by heating to a preset pyrolysis temperature to obtain CFO@C-x (x represents the pyrolysis temperature).

[0015] The mass of the hydrothermal carbon spheres in step two is 0.5-2 g;

[0016] The magnetic stirring time in step two is 4-8 h;

[0017] The heating rate in step two is 5-10 ℃ / min;

[0018] The pyrolysis temperature in step two is 300-700 ℃;

[0019] The pyrolysis time in step two is 2-5 h.

[0020] III. Preparation of cobalt-iron spinel@carbon core-shell microreactor with oxygen vacancy enrichment

[0021] A certain mass of CFO@C-x is immersed in 50 mL of 1 M KBH4 solution, stirred at 500 r / min for a certain period of time, and then thoroughly washed with ultrapure water. The O V product (O V -CFO@C-x) is collected by suction filtration and freeze-dried for later use.

[0022] The mass of CFO@C-x in step three is 0.2-2 g;

[0023] The stirring time in step three is 0.5-2 h.

[0024] The present invention also provides an application in which the oxygen-enriched vacancy cobalt-iron spinel@carbon core-shell microreactor prepared by the above method is used for the degradation of antibiotics in water.

[0025] The beneficial effects of this invention are as follows:

[0026] This invention utilizes a dual synergistic strategy of defect engineering and morphology engineering to construct an oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor (O). V -CFO@C) can efficiently activate PMS to degrade various antibiotics in water. It has a high reaction rate constant, high antibiotic degradation rate, wide pH range, strong anti-interference ability, and low metal ion concentration.

[0027] Compared with the prior art, the structural features and technical advantages of the present invention include:

[0028] I. Core-shell structure design: CoFe2O4 nanoparticles are uniformly loaded on the surface of micron-sized carbon spheres (3–7 μm) to form a heterogeneous interface of "carbon core-spinel shell". The carbon core adsorbs and enriches pollutants and PMS, and the confinement effect shortens the ROS diffusion distance (examples show that the reaction rate is increased by 29.25 times compared with traditional catalysts).

[0029] II. Oxygen Vacancy Engineering: Introducing oxygen vacancies through in-situ reduction with KBH4. V The content increased from 25.05% to 46.06%.

[0030] Key Innovations:

[0031] A "defect-morphology dual engineering synergy" strategy was proposed to break through the technical bottleneck of single-factor control;

[0032] The construction of oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactors exhibits strong catalytic activity (experimentally confirmed). obs =0.2984min -1 );

[0033] Develop a stepwise preparation process of solvothermal-pyrolysis-KBH4 reduction. Attached Figure Description

[0034] Figure 1 Scanning electron microscope image of the hydrothermal carbon spheres prepared in Example 1;

[0035] Figure 2 Scanning electron microscope image of the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor prepared in Example 1;

[0036] Figure 3 Scanning electron microscope image of the cobalt-iron spinel@carbon core-shell microreactor prepared for Comparative Example 1;

[0037] Figure 4 Energy dispersive spectroscopy (EDS) image of the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor prepared in Example 1;

[0038] Figure 5 High-resolution transmission electron microscope image of the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor prepared in Example 1;

[0039] Figure 6 The XRD patterns are those of Examples 1, 2 and Comparative Examples 1, 2, and 3.

[0040] Figure 7 The Raman spectra of Example 1 and Comparative Example 1 are shown below.

[0041] Figure 8 The electron paramagnetic resonance test results are for Example 1 and Comparative Example 1;

[0042] Figure 9 XPS results for O1s of Example 1 and Comparative Example 1;

[0043] Figure 10 The degradation kinetics curves of ciprofloxacin by activated PMS in Examples 1, 2 and Comparative Examples 1, 2 are shown.

[0044] Figure 11 The degradation kinetics curves of ciprofloxacin under activated PMS under different pH conditions in Example 1 are shown.

[0045] Figure 12 The kinetic curves of PMS activation and degradation of ciprofloxacin in river water, lake water and tap water in Example 1 are shown.

[0046] Figure 13 The kinetic curve of ciprofloxacin degradation by activated PMS in Example 1 after 5 cycles;

[0047] Figure 14 The amount of metal ion leaching during the activation of PMS in Example 1 and Comparative Example 3 is denoted as 1. Detailed Implementation

[0048] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0049] The raw materials and instruments used in the following embodiments are all commercially available. Unless otherwise specified, the processes and equipment used in these embodiments are conventional, and the data obtained are the average values ​​of three repeated experiments.

[0050] Degradation efficiency (removal rate) = 1 - (test concentration C / initial concentration C0), where the test concentration is the pollutant concentration in the test solution at the t-th minute of the reaction. In the examples below, t = -30, 0, 2, 4, 6, 8, 10, and 12 minutes. -30 minutes to 0 minutes represents the adsorption equilibrium stage, with PMS added at 0 minutes to initiate the reaction.

[0051] Specific Implementation Method 1: This implementation method is a method for preparing a cobalt-iron spinel microreactor with oxygen-vacancy-rich sites, which is completed according to the following steps:

[0052] I. Preparation of hydrothermal carbon balls:

[0053] The glucose aqueous solution was transferred to a polytetrafluoroethylene high-pressure reactor and placed in an oven for hydrothermal reaction for a certain period of time. The resulting hydrothermal carbon balls were then washed multiple times with ethanol and ultrapure water, the product was separated by filtration, and then dried under vacuum in an oven for later use.

[0054] The concentration of the glucose aqueous solution mentioned in step one is 0.04–0.2 g / mL;

[0055] The pyrolysis temperature mentioned in step one is 180–220°C;

[0056] The hydrothermal time mentioned in step one is 4 to 8 hours.

[0057] II. Preparation of Cobalt-Iron Spinel@Carbon Core-Shell Microreactor

[0058] Disperse the hydrothermal carbon balls in 50 mL of water containing 0.5 M Co(NO3)2·6H2O and 1 M Fe(NO3)3·9H2O (Fe 3+ / Co 2+ The mixture was magnetically stirred for a period of time (molar ratio = 2:1) to achieve metal ion adsorption. Subsequently, the hydrothermal carbon spheres loaded with metal ions were separated by vacuum filtration and then freeze-dried. The freeze-dried hydrothermal carbon spheres loaded with metal ions were placed in a tube furnace and pyrolyzed under N2 protection to a preset pyrolysis temperature to obtain CFO@Cx (x represents the pyrolysis temperature). After natural cooling, the mixture was thoroughly washed with ethanol-ultrapure water and freeze-dried to obtain the product.

[0059] The mass of the hydrothermal charcoal balls mentioned in step two is 0.5–2 g;

[0060] The magnetic stirring time mentioned in step two is 4 to 8 hours;

[0061] The heating rate mentioned in step two is 5-10℃ / min;

[0062] The pyrolysis temperature mentioned in step two is 300℃~700℃;

[0063] The pyrolysis time mentioned in step two is 2 to 5 hours.

[0064] III. Preparation of oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor

[0065] A certain mass of CFO@Cx was immersed in 50 mL of 1 M KBH4 solution, stirred at 500 r / min for a certain period of time, and then thoroughly rinsed with ultrapure water. The O-rich sample was collected by filtration. V Product (O) V -CFO@Cx), then freeze-dry for later use.

[0066] The mass of CFO@Cx mentioned in step three is 0.2–2 g;

[0067] The stirring time mentioned in step three is 0.5 to 2 hours.

[0068] The principle and advantages of this implementation method:

[0069] The principle of this implementation method:

[0070] I. Defect-morphology dual collaborative mechanism

[0071] Defect engineering control: Introducing oxygen vacancies (O2) through reduction treatment V This process reconstructs the local coordination environment of the metal sites (Co / Fe) on the surface of spinel CoFe2O4, enhancing its electron transfer capability. V As an electron capture and storage center, the redox properties of the metal active sites are optimized to improve the activation efficiency for persulfate (PMS). Morphology engineering optimization: A core-shell structure (CFO@C) is constructed using carbon spheres as a carrier to form a confined microreactor. The carbon-based core disperses and anchors CoFe2O4 nanoparticles, preventing aggregation and exposing more active sites; the core-shell interface promotes the enrichment of pollutants and PMS, shortens the reactant diffusion path, and improves mass transfer efficiency.

[0072] II. Synergistic Effect of Electron and Mass Transfer

[0073] The conductivity of the carbon shell accelerates electron transfer between the metal oxide and PMS, and synergistically promotes Co... 2+ / Fe 2+ The redox cycle with PMS continuously generates reactive oxygen species (SO4·) - ·OH 1 O2). The confined microspace extends the half-life of reactive oxygen species, achieving dynamic coupling of "adsorption-activation-degradation" and improving the degradation efficiency of pollutants and the utilization rate of oxidants.

[0074] Advantages of this implementation method

[0075] I. Highly efficient catalytic performance: The catalyst (O) operates at a pyrolysis temperature of 500℃ and with the synergistic effect of oxygen vacancies.V -CFO@C-500) exhibited optimal activity, with a significantly higher degradation rate of ciprofloxacin (CIP) than the control group and superior to existing similar catalysts.

[0076] II. Stability and Environmental Friendliness: The core-shell structure and carbon substrate effectively inhibit metal leaching, maintaining high catalytic activity even after recycling. Pollutants are deeply mineralized, eliminating the risk of secondary pollution and meeting environmental emission standards.

[0077] III. Industrial Application Potential: It exhibits strong resistance to water quality disturbances and maintains high degradation efficiency in a wide pH range (3-9) and complex aquatic environments (Taozi Lake water, Xiangjiang River water, tap water). The process utilizes inexpensive metal salts and biological carbon sources, resulting in a simple and energy-efficient production process.

[0078] The oxygen-vacancy cobalt-iron spinel@carbon core-shell microreactor prepared in this embodiment has the ability to efficiently activate PMS to degrade antibiotics in water.

[0079] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the concentration of the glucose aqueous solution in step one is 0.2 g / mL. All other steps are the same as in Specific Implementation Method One.

[0080] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the temperature of the hydrothermal reaction in step one is 200℃. The other steps are the same as in Specific Implementation Method One or Two.

[0081] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the pyrolysis temperature in step two is 300℃. The other steps are the same as in Specific Implementation Methods One to Three.

[0082] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the metal nitrates mentioned in step two are one or a mixture of several of the following: Co(NO3)2·6H2O, Ni(NO3)2·6H2O, Zn(NO3)2·6H2O, Mg(NO3)2·6H2O, and Fe(NO3)3·9H2O. The other steps are the same as in Specific Implementation Methods One to Four.

[0083] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the pyrolysis time in step two is 3 hours. The other steps are the same as in Specific Implementation Methods One to Five.

[0084] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that the concentration of the KBH4 aqueous solution mentioned in step three is 2M. The other steps are the same as in Specific Implementation Methods One through Six.

[0085] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that the stirring time in step three is 1 hour. The other steps are the same as in Specific Implementation Methods One to Seven.

[0086] The beneficial effects of the present invention are verified using the following embodiments:

[0087] Example 1:

[0088] A method for preparing an oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor is carried out according to the following steps:

[0089] I. Preparation of hydrothermal carbon balls:

[0090] 50 mL of 0.1 g / mL glucose aqueous solution was transferred to a 100 mL polytetrafluoroethylene high-pressure reactor and placed in an oven for hydrothermal reaction for 6 h. The resulting hydrothermal carbon balls were then washed multiple times with ethanol-ultrapure water and dried under vacuum.

[0091] II. Preparation of Cobalt-Iron Spinel@Carbon Core-Shell Microreactor

[0092] Disperse 1g of hydrothermal carbon balls in 50mL of water containing 0.5M Co(NO3)2·6H2O and 1M Fe(NO3)3·9H2O (Fe 3+ / Co 2+ Metal ion adsorption was achieved by magnetic stirring for 6 hours (molar ratio = 2:1). Subsequently, the hydrothermal carbon spheres loaded with metal ions were separated by vacuum filtration and then freeze-dried. The freeze-dried carbon spheres were placed in a tube furnace and pyrolyzed at a programmed temperature of 5℃ / min to 500℃ for 2 hours under N2 protection to obtain CFO@C-500. After natural cooling, the spheres were thoroughly washed with ethanol-ultrapure water and then freeze-dried to obtain the final product.

[0093] III. Preparation of oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor

[0094] Immerse 0.5g of CFO@C-500 in 50mL of 1M KBH4 solution, stir for 2 hours, and then centrifuge to collect the O. V -CFO@C-500, after being thoroughly rinsed with ultrapure water, is freeze-dried for later use.

[0095] To verify the performance of the obtained oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell catalyst in activating PMS to degrade antibiotics, its enrofloxacin degradation performance was tested, including the following steps:

[0096] Example 2:

[0097] The preparation method of an oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor is basically the same as the preparation method of "an oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor" in Example 1, the only difference being that the pyrolysis temperature in step two is 300℃.

[0098] Comparative Example 1:

[0099] The preparation method of a cobalt-iron spinel@carbon core-shell microreactor is basically the same as the preparation method of "a cobalt-iron spinel@carbon core-shell microreactor with oxygen vacancies" in Example 1, except that step three, which uses KBH4 to generate oxygen vacancies, is not performed.

[0100] Comparative Example 2:

[0101] The preparation method of a cobalt-iron spinel@carbon core-shell microreactor is basically the same as the preparation method of "a cobalt-iron spinel@carbon core-shell microreactor" in Comparative Example 2, except that the pyrolysis temperature in step two is 300℃.

[0102] Comparative Example 3:

[0103] A method for preparing cobalt-iron spinel hollow spheres is basically the same as the method for preparing a cobalt-iron spinel@carbon core-shell microreactor in Comparative Example 1. The only difference is that in step two, the freeze-dried carbon spheres are placed in a muffle furnace and heated to 500℃ in air at a programmed temperature of 5℃ / min and pyrolyzed for 2 hours to remove the carbon core, thus obtaining CFO-500. After natural cooling, the spheres are thoroughly washed with ethanol-ultrapure water and then vacuum dried to obtain the final product.

[0104] Figure 1 Scanning electron microscope image of the hydrothermal carbon spheres prepared in Example 1;

[0105] Figure 2 Scanning electron microscope image of the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor prepared in Example 1;

[0106] Figure 3 Scanning electron microscope image of the cobalt-iron spinel@carbon core-shell microreactor prepared for Comparative Example 1;

[0107] from Figures 1 to 3 It can be seen that uniform dispersion of CoFe2O4 nanoparticles on the surface of spherical carbon supports (3–7 μm in diameter) effectively inhibits particle aggregation. The introduction of O... V Then, Example 1 (O) V The CFO@C-500 retains its complete core-shell structure.

[0108] Figure 4 Energy dispersive spectroscopy (EDS) image of the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor prepared in Example 1;

[0109] Figure 5 High-resolution transmission electron microscope image of the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor prepared in Example 1;

[0110] from Figures 4 to 5 As can be seen, energy-dispersive spectroscopy (EDS) analysis shows that Example 1 (O V The uniform distribution of Co, Fe, and O elements in the -CFO@C-500 sample verified the successful synthesis of the target product. High-resolution transmission electron microscopy (HRTEM) images show that Example 1 (O...) V -CFO@C-500) surface has sharp lattice stripes, its and The interplanar spacings correspond to the (440), (311), (220) and (400) crystal planes of CoFe2O4, respectively, confirming that the catalyst has a typical spinel structure.

[0111] Figure 6 The XRD patterns are those of Examples 1, 2 and Comparative Examples 1, 2, and 3.

[0112] from Figure 7 It can be seen that Examples 1 and 2 and Comparative Examples 1, 2 and 3 all have clear characteristic diffraction peaks of the CoFe2O4 spinel phase. The diffraction peaks at 2θ = 18.3°, 30.1°, 35.6°, 37.1°, 43.1°, 53.5°, 57.2° and 62.7° correspond to the (111), (220), (311), (222), (400), (422), (511) and (440) crystal planes of CoFe2O4 (JCPDS#22-1086), respectively.

[0113] Figure 7 The Raman spectra of Example 1 and Comparative Example 1 are shown below.

[0114] Depend on Figure 7 It can be seen that at 689.4cm -1 (A1g), 477.1cm -1 (T2g 2 ) and 304.9cm -1 Characteristic peaks are observed at (E8), corresponding to (1) the symmetric stretching vibration of the M–O (M=Fe / Co) bond at the tetrahedral site, (2) the antisymmetric stretching / bending vibration of the M–O bond at the octahedral site, and (3) the bending vibration of the oxygen sublattice in the AO4 unit. Compared with Comparative Example 1 (CFO@C-500), Example 1 (O V -CFO@C-500) A1g, T2g 2 The E8 peak showed a slight redshift and a decrease in intensity, indicating that OV The introduction of this material leads to distortion of the local coordination environment, triggering structural rearrangement.

[0115] Figure 8 Electron paramagnetic resonance test results of Example 1 and Comparative Example 1;

[0116] Example 1 showed a significant signal at g = 2.003, while Comparative Example 1 showed only a weak response. This demonstrates that KBH4 reduction effectively introduces oxygen vacancies onto the surface of the spinel microreactor.

[0117] Figure 9 XPS results for O1s of Example 1 and Comparative Example 1;

[0118] from Figure 9 It can be seen that KBH4 reduction effectively introduces oxygen vacancies on the surface of the cobalt-iron spinel@carbon core-shell microreactor. Compared with Comparative Example 1 (CFO@C-500), Example 1 (O V The oxygen vacancy content in -CFO@C-500 was significantly increased.

[0119] The specific degradation method for ciprofloxacin using activated PMS was as follows: 10 mg of catalyst was dispersed in 100 mL of a 40 mg / L ciprofloxacin solution. After reaching adsorption equilibrium by magnetic stirring at 500 rpm for 30 min, 1 mL of a 100 mM PMS solution was added to begin the oxidative degradation experiment. The reaction temperature was 25 °C, and the initial pH was not adjusted. 1 mL samples were taken at 2, 4, 6, 8, 10, and 12 min. The reaction solution was filtered through a 0.22 μm filter and added to a liquid chromatography vial containing 0.2 mL of methanol to quench ROS. Subsequently, the concentration of enrofloxacin was determined by liquid chromatography, and the degradation rate was calculated.

[0120] Figure 10 The degradation kinetics curves of ciprofloxacin by activated PMS in Examples 1, 2 and Comparative Examples 1, 2 are shown.

[0121] After testing, the oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor activated PMS prepared in Example 1 showed a degradation rate of 97.64% for ciprofloxacin within 12 min. The oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor activated PMS prepared in Example 2 showed a degradation rate of 92.22% for ciprofloxacin within 12 min. The cobalt-iron spinel@carbon core-shell microreactor activated PMS prepared in Comparative Example 1 showed a degradation rate of 80.04% for ciprofloxacin within 12 min. The cobalt-iron core-shell spinel microreactor activated PMS prepared in Comparative Example 2 showed a degradation rate of 53.53% for ciprofloxacin within 12 min. When PMS was used alone, the degradation rate of ciprofloxacin was 12.05%. The cobalt-iron spinel hollow sphere activated PMS in Comparative Example 3 showed a degradation rate of 52.71% for ciprofloxacin within 12 min.

[0122] Figure 11 The degradation kinetics curves of ciprofloxacin under activated PMS under different pH conditions in Example 1 are shown.

[0123] Depend on Figure 11 It can be seen that at pH = 3, 5, 7, and 9, the degradation rates of ciprofloxacin by activated PMS in Example 1 were 95.73%, 99.87%, 97.65%, and 89.24%, respectively. This demonstrates that Example 1 has a wide pH adaptability.

[0124] Figure 12 The kinetic curves of PMS activation and degradation of ciprofloxacin in river water, lake water and tap water in Example 1 are shown.

[0125] In river water, lake water, and tap water, the degradation rates of CIP by activated PMS in Example 1 were 74.51%, 76.65%, and 84.78%, respectively, indicating that the system in Example 1 has practical application potential.

[0126] Figure 13 The kinetic curve of ciprofloxacin degradation by activated PMS in Example 1 after 5 cycles;

[0127] Depend on Figure 13 It can be seen that after five cycles, the removal rate of ciprofloxacin remained at 88.91%. This demonstrates that the oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor has good recycling performance and practical application potential.

[0128] Figure 14 The amount of metal ion leaching during the activation of PMS in Example 1 and Comparative Example 3 is denoted as 1.

[0129] Example 1 (O) V The Co / Fe leaching amount in the (CFO@C-500) / PMS system was significantly lower than that in Comparative Example 3 (CFO-500) / PMS system, and met the national standard (GB 25467-2010, <1 mg / L). This is attributed to the synergistic effect of the core-shell confinement structure and low metal loading. By constructing a spinel core-shell microreactor, the metal ion leaching amount was significantly reduced. This demonstrates that the oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor possesses strong stability.

[0130] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing an oxygen-vacancy cobalt-iron spinel@carbon core-shell microreactor, characterized in that, The preparation method includes the following steps: (1) Preparation of hydrothermal carbon balls: Transfer glucose aqueous solution to polytetrafluoroethylene high-pressure reactor and place it in an oven for hydrothermal reaction; then the product is thoroughly washed with ethanol-ultrapure water, filtered and separated, and dried in an oven to obtain hydrothermal carbon balls; (2) Preparation of cobalt-iron spinel@carbon core-shell microreactor: Hydrothermal carbon balls were dispersed in 50 mL of an aqueous solution containing 0.5 MCo(NO3)2·6H2O and 1 M Fe(NO3)3·9H2O (Fe 3+ / Co 2+ The metal ions were adsorbed by magnetic stirring for a period of time (molar ratio = 2:1). Subsequently, the hydrothermal carbon balls loaded with metal ions were separated by vacuum filtration and then freeze-dried. The freeze-dried hydrothermal carbon balls loaded with metal ions were placed in a tube furnace and heated to the preset pyrolysis temperature under N2 protection to obtain cobalt-iron spinel@carbon core-shell microreactor CFO@Cx (x represents the pyrolysis temperature). After natural cooling, the product was thoroughly washed with ethanol-ultrapure water and then freeze-dried to obtain the final product. (3) Preparation of oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor: A certain mass of CFO@Cx was immersed in 50 mL of KBH4 solution, stirred for a certain time, and then thoroughly rinsed with ethanol and ultrapure water. The oxygen-rich material was collected by vacuum filtration. V Product (O) V -CFO@Cx), then freeze-dry for later use.

2. The preparation method according to claim 1, characterized in that: In step one, the concentration of the glucose aqueous solution is 0.04–0.2 g / mL; the pyrolysis temperature is 180–220 °C; and the pyrolysis time is 4–8 h.

3. The preparation method according to claim 1, characterized in that: In step two, the mass of the hydrothermal carbon ball is 0.5–2 g; the magnetic stirring time is 4–8 h; the heating rate is 5–10 °C / min; the pyrolysis temperature is 300 °C–700 °C; and the pyrolysis time is 2–5 h.

4. The preparation method according to claim 1, characterized in that: In step three, the mass of CFO@Cx is 0.2–2 g; the stirring rate is 500 r / min; the stirring time is 0.5–2 h; and the concentration of the KBH4 solution is 1 M.

5. The oxygen-vacancy cobalt-iron spinel@carbon core-shell microreactor prepared by the method according to any one of claims 1–4, characterized in that: It has a core-shell structure, with the carbon sphere core having a diameter of 3–7 μm, and CoFe2O4 nanoparticles uniformly loaded on the surface of the carbon core.

6. The application of the oxygen-enriched vacancy cobalt-iron spinel@carbon core-shell microreactor prepared by the preparation method according to any one of claims 1–4 in the degradation of antibiotics in activated persulfate water.

7. The application according to claim 6, characterized in that: The antibiotics include, but are not limited to, ciprofloxacin, and may also be one or more of norfloxacin, carbamazepine, tetracycline, and sulfamethoxazole.

8. The application according to claim 6, characterized in that: The oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor maintains high degradation performance over a wide pH range (3-9) and in complex aquatic environments.

9. The application according to claim 6, characterized in that: The oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor exhibits good recycling performance and practical application potential, maintaining high catalytic activity even after recycling.

10. The application according to claim 6, characterized in that: The oxygen-vacancy-rich cobalt-iron spinel@carbon core-shell microreactor, during the activation of persulfate degradation of antibiotics, Co 2+ Fe 3+ The metal ion leaching amount is low (≤1mg / L), which meets the national standard (GB 25467-2010); Claim Design Notes: In the above example claims, claim 1 is the independent claim, which provides general protection for the preparation method of the oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor; claims 2-5 are dependent claims, which further define the specific parameters and materials in the preparation method; claims 6-10 protect the application and related characteristics of the oxygen-vacancy-enriched cobalt-iron spinel@carbon core-shell microreactor.

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