A microwave-assisted preparation of NiFe2O4@C for selective degradation of antibiotics x catalyst

Abstract

This invention uses waste tires as a carbon source and Ni(NO3)2·6H2O and Fe(NO3)3·9H2O metal precursors to prepare NiFe2O4@C x (x=0.5, 1, 2, 4) porous and fluffy carbon materials were synthesized using a simple and ultrafast microwave-mediated solid-state synthesis of biochar materials derived from waste tires. Rapid microwave treatment not only facilitates the construction of porous and fluffy structures and the formation and exposure of more active sites, but also accelerates mass transfer during the catalytic process. The NiFe2O4 in NiFe2O4@C1 and its large specific surface area can promote the activation of non-free radicals by peroxymonosulfate (PMS). 1 NiFe2O4@C1 system exhibited excellent catalytic performance in the selective degradation of antibiotics with low vertical ionization potential (VIP) using O2. It completely removed oxytetracycline hydrochloride (OTC) within 10 minutes during the catalytic activation of PMS. Furthermore, the NiFe2O4@C1 / PMS system demonstrated highly efficient selective degradation in degradation tests of other antibiotics with low vertical ionization potentials.

Description

Technical Field

[0001] A microwave-assisted preparation of NiFe2O4@C for selective degradation of antibiotics x catalyst Background Technology

[0002] To overcome the limitations of traditional advanced oxidation technologies, selective degradation of organic pollutants has become a research hotspot. Researchers are working to achieve targeted degradation of pollutants by controlling reactive species, based on the differences in molecular structure, atomic composition, and electronic configuration. For example, some researchers have successfully selectively generated singlet oxygen by controlling the second coordination environment of single-atom iron in a carbon-based cathode through boron doping. 1 This method utilizes O2 to suppress non-targeted free radical pathways, thereby achieving selective degradation of electron-rich pollutants. The selective degradation of specific antibiotics in the environment, with its precise and low-interference characteristics, holds promise for solving the key challenge of effectively remediating pollution or ecological damage using traditional technologies. This approach not only helps alleviate the limitations of rational antibiotic use but also reduces the health and ecological risks posed by antibiotic residues in the environment, ultimately achieving a balance between human health, ecological stability, antibiotic pollutant degradation, and industrial development. To date, the selective degradation of structurally complex antibiotics remains extremely challenging.

[0003] Carbon materials have attracted widespread attention due to their unique atomic structure and diverse microstructures, exhibiting significant advantages in areas such as ultra-large specific surface area, strong adsorption capacity, excellent electrical and thermal conductivity, chemical stability under extreme conditions, and high tunability. Meanwhile, waste tires, as a massive type of industrial solid waste with extremely high recycling difficulty, are generated globally over 1.5 billion tires annually, with China alone producing over 300 million waste tires each year. Their characteristics of being "difficult to degrade, highly polluting, and highly risky" pose a serious threat to soil, water bodies, the atmosphere, and ecosystems. Currently, traditional landfilling and open incineration not only fail to fully realize their resource value but also further exacerbate the environmental burden. Therefore, there is an urgent need to develop efficient and clean resource conversion technologies. Against this backdrop, converting waste tires into high-value-added derived carbon has become an important research direction. Summary of the Invention

[0004] A microwave-assisted preparation of NiFe2O4@C for selective degradation of antibiotics x The catalyst is characterized by the successful rapid preparation of porous and fluffy catalytic materials from waste tires, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O through a simple and ultrafast microwave-assisted one-pot solid-phase synthesis method. During the microwave reaction, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O are efficiently converted into NiFe2O4 active species. During the rapid heating process, abundant defects are successfully introduced into the catalytic material.

[0005] NiFe2O4@C x The preparation steps of the catalytic material are as follows: Weigh 1g of waste tire, 2 mmol Ni(NO3)2·6H2O and 4 mmol Fe(NO3)3·9H2O, and mix them thoroughly in a ceramic mortar. Then, place the mixture in a 25mL crucible and pyrolyze it in a 500W commercial microwave oven for 1 minute. After cooling, wash the carbon catalytic material NiFe2O4@C1 with water / ethanol and vacuum dry it; when Ni(NO3)2·6H2O is used, the catalytic material is prepared as follows: Weigh 1g of waste tire, 2 mmol Ni(NO3)2·6H2O and 4 mmol Fe(NO3)3·9H2O, and mix them thoroughly in a ceramic mortar. Then, place the mixture in a 25mL crucible and pyrolyze it in a 500W commercial microwave oven for 1 minute. After cooling, wash the carbon catalytic material NiFe2O 3)2 When the fixed molar masses of ·6H2O and Fe(NO3)3·9H2O are 2 mmol and 4 mmol respectively, the catalyst prepared by adjusting the mass of waste tires is labeled as NiFe2O4@C. x , where x = 0.5, 1, 2 and 4, corresponding to the masses of the discarded tires of 0.5g, 1g, 2g and 4g respectively.

[0006] Catalyst-activated peroxymonosulfate (PMS) degradation of antibiotics: At room temperature, 0.10 g / L of catalyst was added to a 100 mL round-bottom flask containing 50 mL of an aqueous solution of 10 mg / L antibiotic at pH 6.6. PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set 1-minute intervals, 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a specific wavelength. With NiFe₂O₄@Cl as the catalyst, oxytetracycline hydrochloride achieved 100% removal efficiency within 10 min, with a rate constant of 0.384 min. −1 .

[0007] The above describes a microwave-assisted preparation of NiFe2O4@C for selectively degrading antibiotics. x The catalyst is characterized in that, when NiFe2O4@C1 is used as the catalyst, it achieves removal efficiencies of 100.0%, 100.0%, 100.0%, and 87.6% for tetracycline hydrochloride, chlortetracycline, doxycycline, and p-aminobenzenesulfonamide with low vertical ionization potentials within 10 min, respectively. However, for carbamazepine, sulfamethoxazole, norfloxacin, ofloxacin, and ciprofloxacin with high vertical ionization potentials, the removal efficiencies within 10 min are only 3.7%, 8.9%, 4.3%, 6.4%, and 0%, respectively, and these removal efficiencies are comparable to the efficiency of the catalytic material in adsorbing and removing antibiotics with high vertical ionization potentials. In contrast, pure-phase NiFe2O4 spinel shows no significant selectivity for antibiotics with different ionization potentials. Instruction manual illustrations

[0008] Figure 1(a) is a SEM image of NiFe2O4@C1; (b) is a TEM and particle size distribution image of NiFe2O4@C1; (c) is a HRTEM image of NiFe2O4@C1.

[0009] Figure 2 In the middle (a), NiFe2O4 and NiFe2O4@C are catalysts. 0.5 (a) XRD patterns of NiFe2O4@C1, NiFe2O4@C2 and NiFe2O4@C4; (b) N2 adsorption-desorption isotherms of catalysts NiFe2O4 and NiFe2O4@C1; (c) EPR patterns of NiFe2O4 and NiFe2O4@C1.

[0010] Figure 3 (a) and (b) are the XPS full spectra of the catalysts NiFe2O4 and NiFe2O4@C1. (c) is the Ni 2p spectrum, (d) is the Fe 2p spectrum, (e) is the O 1s spectrum, and (f) is the C 1s spectrum. Detailed Implementation The invention will now be described in detail with reference to specific implementation examples.

[0011] Implementation Case 1: NiFe2O4@C x Specific preparation steps of catalytic materials: NiFe2O4@C x Synthesis: 1 g of waste tire, 2 mmol Ni(NO3)2·6H2O, and 4 mmol Fe(NO3)3·9H2O were weighed out in a convenient and rapid manner and thoroughly mixed in a ceramic mortar. The mixture was then placed in a 25 mL crucible and pyrolyzed in a 500 W commercial microwave oven for 1 minute. After cooling, the carbon catalyst NiFe2O4@C1 was washed with water / ethanol and vacuum dried. The catalyst prepared by varying the mass of waste tire when the fixed molar masses of Ni(NO3)2·6H2O and Fe(NO3)3·9H2O were 2 mmol and 4 mmol, respectively, was labeled as NiFe2O4@C1. x , where x = 0.5, 1, 2 and 4, corresponding to the masses of the discarded tires of 0.5g, 1g, 2g and 4g respectively.

[0012] The structure and morphology of the obtained NiFe2O4@C1 sample were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Figure 1 (a) is a SEM image of NiFe2O4@C1. Figure 1 (b) is a TEM image of NiFe2O4@C1 and its particle size distribution. Figure 1(c) is a high-resolution transmission electron microscopy (HRTEM) image of NiFe2O4@C1. The NiFe2O4@C1 composite catalytic material exhibits a porous and fluffy structure. The HRTEM image of the NiFe2O4@C1 sample also shows its porous and fluffy structure, with NiFe2O4 spinel particles uniformly dispersed on the carbon material. A 0.205 nm lattice stripe appears in the HRTEM image, which corresponds to the NiFe2O4 (400) crystal plane.

[0013] The crystal properties of the prepared catalyst were characterized using X-ray diffraction (XRD), and the results are as follows: Figure 2 As shown in Figure a, the XRD pattern of pure spinel-type nickel ferrite (NiFe2O4) shows characteristic diffraction peaks at 2θ of 30.2°, 35.6°, 43.3°, 53.6°, 57.3°, and 62.9°, corresponding to the (220), (311), (400), (422), (511), and (440) crystal planes of NiFe2O4, respectively. This crystal plane indexing result is consistent with the standard XRD card (PDF#44-1485), confirming the successful synthesis of spinel-type NiFe2O4. For NiFe2O4@C prepared using waste tires as a carbon source... x For the composite materials (x=0.5, 1, 2, 4), all characteristic peaks in their XRD patterns can be indexed as diffraction peaks corresponding to those on the standard XRD card (PDF#44-1485). These results indicate that carbon loading did not alter the phase structure of NiFe2O4; the main phase of the composite material remains spinel-type NiFe2O4. The characteristic peaks of pure-phase NiFe2O4 are sharp and have high intensity, indicating good crystallinity. Conversely, with increasing amounts of waste tires added, the NiFe2O4@C... x The intensity of the (002) diffraction peak corresponding to graphitic carbon gradually increases, and the peak shape shows a broadening trend, indicating that NiFe2O4 has been successfully loaded onto waste tire-derived carbon materials. NiFe2O4@C 0.5 The characteristic peaks of the (311) and (400) crystal planes in NiFe2O4@C1 gradually broadened and shifted to higher angles, indicating that the degree of lattice distortion of the spinel phase in the composite material continuously intensified with the increase of waste tire usage; when the amount of waste tire added was further increased, the diffraction peaks did not show additional broadening or shift. Nitrogen adsorption-desorption isotherms were used (… Figure 2 b) The specific surface area (SSA) of NiFe2O4@ and NiFe2O4@C1 was characterized. The results showed that both samples exhibited a type IV isotherm, indicating that the catalyst possesses a mesoporous structure. Compared to pure NiFe2O4, the specific surface area of ​​the NiFe2O4@C1 composite material supported on waste tire-derived carbon was significantly increased: the specific surface area of ​​NiFe2O4 was only 12.873 m² / g, while that of NiFe2O4@C1 reached 74.442 m² / g.2 / g. The significant increase in specific surface area stems from the multiple structural optimizations brought about by the introduction of waste tire-derived carbon carriers. Firstly, the porous framework of waste tire-derived carbon itself provides a large number of intrinsic channels for the composite material, directly constituting the main contributor to the specific surface area. Secondly, the steric hindrance effect of the carbon carrier can effectively inhibit the agglomeration of NiFe2O4 particles at high temperatures, making them highly dispersed and anchored on the carbon surface and inside the channels. In addition, new interfacial gap pores are formed between NiFe2O4 and carbon during the composite process, further increasing the mesopore volume and effective adsorption area of ​​the material, ultimately leading to a significant increase in the specific surface area of ​​the composite material. Figure 2 c shows the electron paramagnetic resonance (EPR) spectra of NiFe2O4 and NiFe2O4@C1. A characteristic resonance signal appears at g=2.003 in both samples, originating from localized electrons at oxygen vacancy sites. The signal intensity of NiFe2O4@C1 is significantly higher than that of pure NiFe2O4, indicating a higher relative concentration of oxygen vacancies in the carbon-modified catalyst.

[0014] The surface composition and elemental valence state characteristics of NiFe2O4 and NiFe2O4@C1 were characterized using X-ray photoelectron spectroscopy (XPS). The full XPS spectrum of NiFe2O4@C1 is shown below. Figure 3 As shown in a and 3b, the results indicate that Ni, Fe, C, and O are the four main elements detected on its surface. The Ni 2p spectrum of pure NiFe2O4 contains two sets of spin-orbit splitting peaks: the peaks at 855.5 eV and 873.3 eV are attributed to Ni, respectively. 3+ 2p 3 / 2 with Ni 3+ 2p 1 / 2 The peaks at 854.3 eV and 871.8 eV correspond to Ni 2+ 2p 3 / 2 with Ni 2+ 2p 1 / 2 The satellite peaks are located at 861.3 eV and 879.8 eV, respectively. In contrast, Ni in NiFe2O4@C1... 3+ The orbital peaks shifted to 856.1 eV and 873.8 eV, Ni 2+ The orbital peaks correspond to 855.8 eV and 872.3 eV, while the satellite peaks are located at 861.8 eV and 880.6 eV. Figure 3 c). Fe 2p spectrum as shown Figure 3 As shown in d: In pure NiFe2O4, Fe 2+ 2p 3 / 2 with Fe 2+ 2p 1 / 2 The peaks are located at 710.1 eV and 723.9 eV, respectively, for Fe. 3+ 2p3 / 2 with Fe 3+ 2p 1 / 2 The peaks are located at 712.7 eV and 725.6 eV, and the satellite peak is located at 718.2 eV; while in NiFe2O4@C1, Fe 2+ The orbital peaks are 710.6 eV and 724.3 eV, Fe 3+ The orbital peaks are 713.2 eV and 726.0 eV, and the satellite peak is 718.6 eV. In NiFe₂O₄@C₁, the binding energies of Ni and Fe shift towards higher binding energies, and the satellite peak intensity decreases. These changes indicate a decrease in the electron cloud density of Ni and Fe, a reduction in unpaired electrons, and a weakening of spin-orbit coupling, thus causing the metal spin state to change from the high spin in pure NiFe₂O₄ to the low spin in NiFe₂O₄@C₁. Furthermore, compared to pure NiFe₂O₄, the Ni in NiFe₂O₄@C₁... 2+ with Fe 2+ The significantly increased intensity of characteristic peaks indicates that the loading of waste tire-derived biochar is conducive to the formation of low-valence metal species. These species can optimize electron transfer efficiency in catalytic reactions and have a positive effect on improving catalytic performance. (O 1s spectrum) Figure 3 e) Peak fitting can be analyzed into three characteristic peaks: surface lattice oxygen (O) lat 530.0–530.3 eV), oxygen vacancies (O V (531.1–531.3 eV) and adsorbed oxygen (O ads (532.3–532.6 eV). After introducing waste tire-derived carbon to prepare NiFe2O4@C1, the oxygen vacancy ratio was significantly increased compared to pure NiFe2O4. This change not only reflects the increase in potential active sites of the catalyst, but also, to some extent, corroborates the lattice distortion phenomenon of NiFe2O4@C1 observed in XRD characterization. Figure 3 C1s spectrum analysis of f shows that the surface carbon species mainly include graphitic carbon (C–C bond, 284.8 eV) and ether-bonded carbon (C–O–C bond, 286.2 eV), with graphitic carbon being the predominant form. Its excellent conductivity is crucial for enhancing electron transfer during the catalytic process, providing structural support for improving catalytic performance.

[0015] Implementation Case 2 (See Table 1, Item 1 for responses) At room temperature, 0.3 g / L PMS was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6) to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at 357 nm. At a reaction time of 10 minutes, the degradation rate of TCH by pure PMS was only 4.3%, indicating that the rate constant of PMS for OTC degradation (0.0038 min) is limited. −1 It is very small.

[0016] Implementation Case 3 (See Table 1, Item 2 for responses) At room temperature, 0.10 g / L of catalyst C was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the degradation rate of OTC by catalyst C was found to be 25.9%, with a rate constant of 0.0061 min⁻¹. −1 .

[0017] Implementation Case 4 (See Table 1, Item 3 for the response) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a wavelength of 357 nm. At a reaction time of 10 minutes, the NiFe₂O₄ catalyst showed a degradation rate of 76.3% for OTC, with a rate constant of 0.144 min⁻¹. −1 .

[0018] Implementation Case 5 (See Table 1, Item 4 for responses) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed a 100.0% degradation rate for OTC, with a rate constant as high as 0.381 min⁻¹. −1 .

[0019]

[0020] Implementation Case 6 (See Table 2, Item 1 for the response) At room temperature, 0.10 g / L of NiFe2O4@C was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). 0.5 Catalyst. PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a wavelength of 357 nm. At a reaction time of 10 minutes, NiFe₂O₄@C was observed to... 0.5 The catalyst achieved a degradation rate of 81.9% for OTC, with a rate constant of 0.245 min. −1 .

[0021] Implementation Case 7 (See Table 2, Item 2 for responses) At room temperature, 0.10 g / L of NiFe₂O₄@C₂ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₂ catalyst showed a degradation rate of 95.4% for OTC, with a rate constant of 0.271 min⁻¹. −1 .

[0022] Implementation Case 8 (See Table 2, Item 3 for responses) At room temperature, 0.10 g / L of NiFe₂O₄@C₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₄ catalyst showed a degradation rate of 78.9% for OTC, with a rate constant of 0.182 min⁻¹. −1 .

[0023]

[0024] Implementation Case 9 (Degradation of OTC by 0.06 g / L NiFe2O4@C1) At room temperature, 0.06 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed a degradation rate of 83.6% for OTC.

[0025] Implementation Case 10 (Degradation of OTC by 0.08 g / L NiFe2O4@C1) At room temperature, 0.06 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed a degradation rate of 83.6% for OTC.

[0026] Implementation Case 11 (Degradation of OTC by 0.10 g / L NiFe2O4@C1) At room temperature, 0.06 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed a degradation rate of 83.6% for OTC.

[0027] Implementation Case 12 (Degradation of OTC by 0.12 g / L NiFe2O4@C1) At room temperature, 0.06 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed a degradation rate of 83.6% for OTC.

[0028] Implementation Case 13 (See Table 3, Items 1-5 for responses) At room temperature, 0.15 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of OTC aqueous solution (10 mg / L, pH=6.6). The required amount of PMS at a concentration of 0.3 g / L was then added to the reactor to initiate degradation. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of the antibiotic was then detected at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the degradation rate of TCH by the NiFe₂O₄@C₁ catalyst was 100%. The OTC degradation rate was 96.3% after the second centrifugation, 93.2% after the third centrifugation, 91.6% after the fourth centrifugation, and 89.4% after the fifth centrifugation.

[0029]

[0030] Implementation Case 14 (Reaction details are in Table 4, Degradation of Tetracycline Hydrochloride (TCH, Vertical Ionization Potential (VIP) = 6.223) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of tetracycline hydrochloride (TCH) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of the antibiotic was then determined using a UV-Vis spectrophotometer at a wavelength of 357 nm. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed an adsorption rate of 24.7% for tetracycline hydrochloride (TCH) and a removal rate of 100.0%.

[0031] Implementation Case 15 (Reaction shown in Table 4, Degradation of Chlortetracycline Hydrochloride (CTC, VIP=6.233) by NiFe2O4@C1 Catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of chlortetracycline hydrochloride (CTC) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 355 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed an adsorption rate of 22.1% for CTC and a removal rate of 100.0%.

[0032] Implementation Case 16 (Reaction details are in Table 4, Degradation of Doxycycline (DOX, VIP=6.428) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of doxycycline (DOX) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 350 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄@C₁ catalyst showed an adsorption rate of 18.7% for DOX and a removal rate of 100.0%.

[0033] Implementation Case 17 (Reaction details are in Table 4, Degradation of p-aminobenzenesulfonamide (SA, VIP = 6.440) using NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of an aqueous solution of p-aminobenzenesulfonamide (SA) (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of the antibiotic was then determined using a UV-Vis spectrophotometer at a wavelength of 260 nm. At a reaction time of 10 minutes, the adsorption rate of SA by the NiFe₂O₄@C₁ catalyst was found to be 20.3%, and the removal rate was 87.6%.

[0034] Implementation Case 18 (Reaction details are in Table 4, Degradation of Carbamazepine (CBZ, VIP=6.529) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of carbamazepine (CBZ) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 285 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the adsorption rate of CBZ by the NiFe₂O₄@C₁ catalyst was found to be 15.6%, while the removal rate was 3.7%. Since the removal rate was lower than the adsorption rate, it was concluded that the NiFe₂O₄@C₁ catalyst could not degrade carbamazepine.

[0035] Implementation Case 19 (Reaction details are shown in Table 4, Degradation of sulfamethoxazole (SMX, VIP=6.533) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of sulfamethoxazole (SMX) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 257 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the adsorption rate of SMX by the NiFe₂O₄@C₁ catalyst was found to be 13.8%, while the removal rate was 8.9%. Since the removal rate was lower than the adsorption rate, it was concluded that the NiFe₂O₄@C₁ catalyst could not degrade sulfamethoxazole.

[0036] Implementation Case 20 (Reaction details are shown in Table 4, Degradation of Norfloxacin (NFL, VIP=6.701) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of norfloxacin (NFL) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 273 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the adsorption rate of NFL by the NiFe₂O₄@C₁ catalyst was 14.6%, and the removal rate was 4.3%. Since the removal rate was lower than the adsorption rate, it was concluded that the NiFe₂O₄@C₁ catalyst could not degrade norfloxacin.

[0037] Implementation Case 21 (Reaction details are shown in Table 4, Degradation of ofloxacin (OFL, VIP=6.784) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of ofloxacin (OFL) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of the antibiotic was then determined using a UV-Vis spectrophotometer at a wavelength of 290 nm. At a reaction time of 10 minutes, the adsorption rate of OFL by the NiFe₂O₄@C₁ catalyst was found to be 18.2%, while the removal rate was 6.4%. Since the removal rate was lower than the adsorption rate, it was concluded that the NiFe₂O₄@C₁ catalyst could not degrade ofloxacin.

[0038] Implementation Case 22 (Reaction details are shown in Table 4, Degradation of Ciprofloxacin (CIP, VIP=6.826) by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L of NiFe₂O₄@C₁ catalyst was added to a 100 mL round-bottom flask containing 50 mL of ciprofloxacin (CIP) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 277 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the adsorption rate of CIP by the NiFe₂O₄@C₁ catalyst was 13.4%, with a removal rate of 0%. Since the removal rate was lower than the adsorption rate, it was concluded that the NiFe₂O₄@C₁ catalyst could not degrade ciprofloxacin.

[0039]

[0040] Implementation Case 23 (Reaction details are in Table 5, Degradation of Tetracycline Hydrochloride (TCH, VIP=6.223) by NiFe2O4 Catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of tetracycline hydrochloride (TCH) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of the antibiotic was then determined using a UV-Vis spectrophotometer at a wavelength of 357 nm. At a reaction time of 10 minutes, the adsorption rate of tetracycline hydrochloride (TCH) by the NiFe₂O₄ catalyst was found to be 6.8%, and the removal rate was 65.8%.

[0041] Implementation Case 24 (Reaction details are shown in Table 5, Degradation of Chlortetracycline Hydrochloride (CTC, VIP=6.233) by NiFe2O4 Catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of chlortetracycline hydrochloride (CTC) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 355 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄ catalyst showed an adsorption rate of 7.2% and a removal rate of 40.9% for CTC.

[0042] Implementation Case 25 (Reaction details are in Table 5, Degradation of Doxycycline (DOX, VIP=6.428) by NiFe2O4 catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of doxycycline (DOX) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a wavelength of 350 nm. At a reaction time of 10 minutes, the NiFe₂O₄ catalyst showed an adsorption rate of 7.4% and a removal rate of 64.4% for DOX.

[0043] Implementation Case 26 (Reaction details are in Table 5, Degradation of p-aminobenzenesulfonamide (SA, VIP = 6.440) by NiFe2O4 catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of an aqueous solution of p-aminobenzenesulfonamide (SA) (10 mg / L, pH=6.6). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of the antibiotic was then determined using a UV-Vis spectrophotometer at a wavelength of 260 nm. At a reaction time of 10 minutes, the adsorption rate of SA by the NiFe₂O₄ catalyst was found to be 6.5%, and the removal rate was 36.9%.

[0044] Implementation Case 27 (Reaction details are in Table 5, Degradation of Carbamazepine (CBZ, VIP=6.529) by NiFe2O4 Catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of carbamazepine (CBZ) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a wavelength of 285 nm. At a reaction time of 10 minutes, the adsorption rate of CBZ by the NiFe₂O₄ catalyst was found to be 9.3%, and the removal rate was 28.4%.

[0045] Implementation Case 28 (Reaction details are in Table 5, Degradation of sulfamethoxazole (SMX, VIP=6.533) by NiFe2O4 catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of sulfamethoxazole (SMX) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a wavelength of 257 nm. At a reaction time of 10 minutes, the adsorption rate of SMX by the NiFe₂O₄ catalyst was found to be 8.2%, and the removal rate was 32.8%.

[0046] Implementation Case 29 (Reaction details are shown in Table 5, Degradation of Norfloxacin (NFL, VIP=6.701) by NiFe2O4 catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of norfloxacin (NFL) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 273 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄ catalyst showed an adsorption rate of 6.6% and a removal rate of 17.7% for NFL.

[0047] Implementation Case 30 (Reaction details are in Table 5, Degradation of ofloxacin (OFL, VIP=6.784) by NiFe2O4 catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of ofloxacin (OFL) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then measured at 290 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the NiFe₂O₄ catalyst showed an adsorption rate of 9.4% and a removal rate of 13.3% for OFL.

[0048] Implementation Case 31 (See Table 5 for reaction details, degradation of ciprofloxacin (CIP, VIP=6.826) by NiFe2O4 catalyst) At room temperature, 0.10 g / L NiFe₂O₄ catalyst was added to a 100 mL round-bottom flask containing 50 mL of ciprofloxacin (CIP) aqueous solution (10 mg / L, pH=6.6). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then determined using a UV-Vis spectrophotometer at a wavelength of 277 nm. At a reaction time of 10 minutes, the adsorption rate of CIP by the NiFe₂O₄ catalyst was found to be 8.8%, and the removal rate was 19.2%.

[0049]

[0050] Implementation Case 32 (The effect of tert-butanol (TBA) quencher on the degradation of OTC by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L NiFe2O4@C1 catalyst and 200 mM TBA were added to a reactor containing 50 mL of OTC aqueous solution (10 mg / L). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then detected at 357 nm using a UV-Vis spectrophotometer. After 10 minutes of reaction, the TCH removal efficiency decreased to 96.3% after the addition of TBA, indicating that ·OH contributed almost nothing to the degradation of OTC.

[0051] Implementation Case 33 (The effect of methanol quencher on the degradation of OTC by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L NiFe2O4@C1 catalyst and 200 mM methanol were added to a reactor containing 50 mL of OTC aqueous solution (10 mg / L). PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then detected at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the OTC removal efficiency decreased to 95.2% with the addition of methanol. Quenching results with methanol and tert-butanol showed that ·OH and SO42- ·- None of them participated in the degradation of OTC.

[0052] Implementation Case 34 (The effect of curcumin (Cur) quencher on the degradation of OTC by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L NiFe2O4@C1 catalyst and 20 mM curcumin (Cur) were added to a reactor containing 50 mL of OTC aqueous solution (10 mg / L). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then detected at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, it was found that the OTC removal efficiency decreased to 34.3% with the addition of Cur, indicating that… 1 O2 makes a significant contribution to the removal of OTC.

[0053] Implementation Case 35 (The effect of chloroform (CHCl3) quencher on the degradation of OTC by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L NiFe2O4@C1 catalyst and 20 mM chloroform (CHCl3) were added to a reactor containing 50 mL of OTC aqueous solution (10 mg / L). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then detected at 357 nm using a UV-Vis spectrophotometer. At a reaction time of 10 minutes, the OTC removal efficiency decreased to 95.2% with the addition of CHCl3. Chloroform quenching results indicated that O2 in the NiFe2O4@C1 system... ·- It makes no contribution to the TCH removal process.

[0054] Implementation Case 36 (The effect of methyl benzene sulfoxide (PMSO) quencher on the degradation of OTC by NiFe2O4@C1 catalyst) At room temperature, 0.10 g / L NiFe₂O₄@C₁ catalyst and 10 mM methylphenyl sulfoxide (PMSO) were added to a reactor containing 50 mL of OTC aqueous solution (10 mg / L). PMS at a predetermined concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At predetermined time intervals (reaction solution was sampled every 1 minute), 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The antibiotic concentration was then detected at 357 nm using a UV-Vis spectrophotometer. After 10 minutes of reaction, the OTC removal efficiency decreased to 96.7% with the addition of PMSO. The PMSO quenching results indicate that high-valence metals contribute very little to OTC degradation in the NiFe₂O₄@C₁ system.

Claims

1. A microwave-assisted preparation method for selectively degrading antibiotics using NiFe2O4@C x Catalyst, characterized in that, A simple and ultrafast microwave-assisted one-pot solid-state synthesis method was successfully used to rapidly prepare porous and fluffy catalytic materials from waste tires, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O. During the microwave reaction, Ni(NO3)2·6H2O and Fe(NO3)3·9H2O were efficiently converted into NiFe2O4 active species. During the rapid heating process, abundant defects were successfully introduced into the catalytic material. NiFe2O4@C x The preparation steps of the catalyst material are as follows: 1 g of waste tire, 2 mmol Ni(NO3)2·6H2O and 4 mmol Fe(NO3)3·9H2O were weighed and thoroughly mixed in a ceramic mortar. The mixture was then placed in a 25 mL crucible and pyrolyzed in a 500W commercial microwave oven for 1 minute. After cooling, the carbon catalyst NiFe2O4@C1 was washed with water / ethanol and vacuum dried. When the fixed molar masses of Ni(NO3)2·6H2O and Fe(NO3)3·9H2O were 2 mmol and 4 mmol respectively, the catalyst prepared by adjusting the mass of the waste tire was labeled as NiFe2O4@C1. x , where x = 0.5, 1, 2 and 4, corresponding to the masses of the discarded tires of 0.5 g, 1 g, 2 g and 4 g respectively; Catalyst-activated peroxymonosulfate (PMS) degradation of antibiotics: At room temperature, 0.10 g / L of catalyst was added to a 100 mL round-bottom flask containing 50 mL of an aqueous solution of 10 mg / L antibiotic at pH 6.

6. PMS at a set concentration of 0.3 g / L was added to the reactor to initiate the degradation process. At set 1-minute intervals, 1 mL of the reaction solution was drawn, filtered through a 0.22 µm microporous membrane, and squeezed into a centrifuge tube containing 2 mL of methanol. The concentration of antibiotics was then determined using a UV-Vis spectrophotometer at a specific wavelength. With NiFe₂O₄@Cl as the catalyst, oxytetracycline hydrochloride achieved 100% removal efficiency within 10 min, with a rate constant of 0.384 min. −1 .

2. The microwave-assisted preparation of NiFe2O4@C for selective degradation of antibiotics according to claim 1. x The catalyst is characterized by: When NiFe2O4@C1 is used as a catalyst, it achieves removal efficiencies of 100.0%, 100.0%, 100.0%, and 87.6% for tetracycline hydrochloride, chlortetracycline, doxycycline, and p-aminobenzenesulfonamide with low vertical ionization potentials, respectively, within 10 min. However, for carbamazepine, sulfamethoxazole, norfloxacin, ofloxacin, and ciprofloxacin with high vertical ionization potentials, the removal efficiencies within 10 min are only 3.7%, 8.9%, 4.3%, 6.4%, and 0%, respectively, and these efficiencies are comparable to those of the catalytic material adsorbing and removing antibiotics with high vertical ionization potentials. In contrast, pure-phase NiFe2O4 spinel shows no significant selectivity for antibiotics with different ionization potentials.

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