A hollow tubular ZnCo-X spinel catalyst for efficient degradation of antibiotics in water

Abstract

The present invention uses oxalic acid, Co(NO3)2·6H2O, and Zn(NO3)·6H2O as raw materials to prepare a hollow tubular ZnCo-X composite oxide catalytic material through grinding. The preparation process is simple, rapid, low in energy consumption, and less polluting to the environment. The hollow tubular structure of ZnCo-X can expose more active sites, accelerating the mass transfer process of reactants on the surface. The composite components of the ZnCo-X spinel can activate peroxymonosulfate (PMS) to generate a large number of non-free radicals ( 1 O2) and free radicals (·OH, SO4 ·‑ , ·O2 ‑ ) to remove antibiotics in water. The ZnCo-1 catalytic material exhibits excellent catalytic performance in the reaction of activating peroxymonosulfate (PMS) to degrade tetracycline. After 5 minutes of reaction, it can completely degrade tetracycline in water. In addition, the ZnCo-1 catalyst also shows wide applicability in the degradation of other antibiotic pollutants in water.

Description

Technical Field

[0001] A hollow tubular ZnCo-X spinel catalyst for efficiently degrading antibiotics in water bodies. Background Art

[0002] New pollutants mainly include persistent organic pollutants, endocrine disruptors, antibiotics, microplastics, etc. Antibiotics in water bodies are hydrophilic, highly accumulative and stable, making antibiotics easy to accumulate in organisms, which can cause serious environmental pollution and pose a threat to human health. In view of the antibiotic pollution in environmental water bodies, it is urgent to find safe, effective and economical remediation technologies.

[0003] At present, for the antibiotic remediation technology in water bodies, advanced oxidation processes (AOPs) based on the free radical catalytic oxidation mechanism have received extensive attention. Among them, the advanced oxidation technology of sulfate radical (SO4 •- ) has many advantages: the redox potential of reactive oxygen species (ROS) is higher, the applicable pH range is wider, the selectivity and effectiveness are better, and it can completely oxidize and degrade antibiotics. In the heterogeneous catalytic activation PMS oxidation reaction system, more studied are catalysts containing Co, Fe, Cu, Mn, etc., all of which have the ability to activate PMS. As a transition metal oxide, Co3O4 has a unique crystal structure and electronic properties and has been widely used as a catalyst for PMS activation. However, the catalytic performance of Co3O4 still needs to be improved, especially for the degradation of antibiotics in water bodies. Modifying Co3O4 to improve its catalytic performance has become a research hotspot. To solve such problems, the catalytic performance of Co3O4 is mainly optimized by methods such as doping, morphology control and specific surface area regulation. However, the modification methods for Co3O4 usually have expensive raw material costs, complex synthesis processes, high energy consumption and generate a large amount of sewage, and are not suitable for large-scale industrial production.

[0004] In this work, we prepared hollow tubular ZnCo-X spinel by a grinding method that is simple, fast, low in energy consumption and less polluting to the environment. The obtained ZnCo-X catalyst has high antibiotic degradation efficiency and can completely degrade antibiotic pollutants in water bodies in a short time. Summary of the Invention

[0005] The present invention uses oxalic acid, Co(NO3)2·6H2O and Zn(NO3)·6H2O (Zn(NO3)·6H2O:Co(NO3)2·6H2O = X:1, X = 0.5, 1, 2, 4) as raw materials. After grinding evenly, it is calcined in a muffle furnace at 400 °C for 3 h to prepare ZnCo-X (X = 0.5, 1, 2, 4) catalytic materials. The preparation method provided by the invention is simple, the preparation process is fast, the energy consumption is low, and the environmental pollution is less. The prepared hollow tubular ZnCo-X (X = 0.5, 1, 2, 4) has a large specific surface area. It can be used to activate PMS to degrade antibiotics in water, and the catalyst is easy to recycle and reuse.

[0006] The present invention discloses an efficient method for synthesizing ZnCo-X composite oxides by grinding from oxalic acid, Co(NO3)2·6H2O and Zn(NO3)·6H2O (Co(NO3)2·6H2O:Zn(NO3)·6H2O = 1:X, X = 0.5, 1, 2, 4), and good results have been achieved in activating PMS to degrade antibiotics represented by tetracycline. The technical scheme adopted is: through a simple, fast, low-energy-consuming and less environmentally polluting grinding method, oxalic acid, Co(NO3)2·6H2O and Zn(NO3)·6H2O are put into a mortar and ground, and then calcined in a muffle furnace at 400 °C for 3 h to prepare ZnCo-X (X = 0.5, 1, 2, 4) catalytic materials. The ZnCo-X (X = 0.5, 1, 2, 4) prepared by the grinding method has a hollow tubular structure, which can not only expose more active sites, but also accelerate the mass transfer process of reactants on the surface. The composite components of the ZnCo-X (X = 0.5, 1, 2, 4) catalytic material can promote peroxymonosulfate (PMS) to generate a large number of non-free radicals ( 1 O2) and free radicals (·OH, SO4 ·- , ·O2 - ) to remove antibiotics in water.

[0007] The synthesis steps of the above ZnCo-X (X = 0.5, 1, 2, 4) catalytic material are as follows: In a typical synthesis process, 36 mmol of oxalic acid, 8 mmol of Co(NO3)2·6H2O and Zn(NO3)·6H2O, Co(NO3)2·6H2O:Zn(NO3)·6H2O = 1:X, X = 0.5, 1, 2, 4, are put into a mortar, and the mixture is ground into a paste by a mortar rod. Then, the paste-like mixture is transferred to a crucible and heated in a muffle furnace from room temperature to 400 °C at a rate of 10 °C / min and kept for 3 h. After cooling, the catalytic material ZnCo-X (X = 0.5, 1, 2, 4) with a hollow tubular structure is obtained.

[0008] Catalyst activated PMS to degrade antibiotics in water: Under the reaction temperature of 25 °C, 0.1 g / L of catalyst was added to a 250 mL beaker containing 100 mL of antibiotic aqueous solution (20 mg / L, pH=6.5). After stirring for 30 min to reach adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to start the degradation reaction. 2 mL of the reaction solution was drawn out with a syringe at 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min, respectively. The solution was filtered using a 0.22 µm microporous membrane and injected into a test tube containing 2 mL of methanol. After shaking, the concentration of antibiotics in the water was determined using a UV-visible spectrophotometer under specific wavelength conditions. When the reaction time was 5 min, 100% degradation of tetracycline in water could be achieved using ZnCo-1 as the catalyst, and the rate constant was as high as 1.217 min -1 .

[0009] The hollow tubular ZnCo-X spinel catalyst for efficiently degrading antibiotics in water is characterized in that: when ZnCo-1 is used as a catalyst, after 5 minutes of reaction, antibiotics such as sulfamethazine, sulfamethoxazole, ciprofloxacin, oxytetracycline hydrochloride and florfenicol in water can be degraded by 100%, 100%, 100%, 100% and 98.6%, respectively, and the rate constants are as high as 1.158 min -1 , 1.136 min -1 , 1.048 min -1 , 1.029 min -1 and 0.954 min -1 , which has broad application prospects in the field of water pollution control.

[0010] The above-mentioned hollow tubular ZnCo-X spinel catalyst for efficiently degrading antibiotics in water bodies is characterized by: compared with the traditional technology for preparing ZnCo-X spinel, the preparation method of the present invention is simple, fast, low in energy consumption and less in environmental pollution, and the obtained ZnCo-X spinel catalyst has a higher catalytic efficiency and has prospects for industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 (a) is the SEM image of ZnCo-1 catalyst. Figure 1 (b) is the TEM image of ZnCo-1. Figure 1 (c) HRTEM image of ZnCo-1. Figure 1 (d) is a high-angle annular dark field scanning transmission image (HAADF-STEM). Figure 1 (e) EDS element mapping of ZnCo-1.

[0012] Figure 2 N₂ adsorption - desorption isotherm of ZnCo - 1 catalyst (inset: pore size distribution).

[0013] Figure 3 XRD patterns of ZnO, Co₃O₄, ZnCo - 0.5, ZnCo - 1, ZnCo - 2, and ZnCo - 4 catalysts.

[0014] Figure 4 FT - IR spectra of ZnO, Co₃O₄, ZnCo - 0.5, ZnCo - 1, ZnCo - 2, and ZnCo - 4 catalysts. Detailed implementation mode

[0015] The present invention will be described in detail below in combination with specific implementation cases.

[0016] Implementation case 1:

[0017] Specific preparation steps of ZnCo - X, ZnO, and Co₃O₄ catalytic materials

[0018] Synthesis of ZnCo - X: In a typical synthesis process, 36 mmol of oxalic acid, 8 mmol of Co(NO₃)₂·6H₂O and Zn(NO₃)·6H₂O, with Co(NO₃)₂·6H₂O : Zn(NO₃)·6H₂O = 1 : X, X = 0.5, 1, 2, 4, were put into a mortar and ground into a paste by a mortar rod. Then, the paste - like mixture was transferred to a crucible and heated in a muffle furnace from room temperature to 400 °C at a rate of 10 °C / min and held for 3 h. After cooling, the catalytic material ZnCo - X (X = 0.5, 1, 2, 4) with a hollow tubular structure was obtained.

[0019] Synthesis of ZnO: 36 mmol of oxalic acid and 12 mmol of Zn(NO₃)·6H₂O were put into a mortar and ground into a paste by a mortar rod. Then, the paste - like mixture was transferred to a crucible and heated in a muffle furnace from room temperature to 400 °C at a rate of 10 °C / min and held for 3 h. After cooling, the obtained catalytic material was named ZnO.

[0020] Synthesis of Co₃O₄: 12 mmol of Co(NO₃)₂·6H₂O and 36 mmol of oxalic acid were put into a mortar and ground into a paste by a mortar rod. Then, the paste - like mixture was transferred to a crucible and heated in a muffle furnace from room temperature to 400 °C at a rate of 10 °C / min and held for 3 h. After cooling, the catalytic material Co₃O₄ with a hollow tubular structure was obtained.

[0021] After obtaining ZnCo-X (X = 0.5, 1, 2, 4) samples, the structure and morphology of the obtained catalytic materials were characterized by scanning electron microscopy and transmission electron microscopy: Figure 1 (a) is the SEM image of ZnCo-1. Figure 1 (b) is the TEM image of ZnCo-1. The ZnCo-1 composite oxide material has the basic characteristics of a hollow tubular structure. This indicates that grinding is beneficial to the formation of a tubular structure. As a pore-forming agent and fuel, the gas products (CO2, water vapor, etc.) generated by the combustion decomposition of oxalic acid are released, thus forming a hollow pore structure. Figure 1 (c) is the HRTEM image of ZnCo-1. It can be seen from the figure that lattice fringes with lattice spacings of 0.242 nm and 0.260 nm appear in the ZnCo-1 image, which belong to the (311) crystal plane of ZnCo2O4 / Co3O4 and the (002) crystal plane of ZnO, respectively. Figure 1 (d) is the high-angle annular dark-field scanning transmission image (HAADF-STEM) of ZnCo-1. Figure 1 (e) is the EDS elemental mapping image of ZnCo-1. As can be seen from Figure 1 e, the Co, Zn, and O elements are evenly distributed, which may be attributed to the complexing effect of oxalic acid.

[0022] Figure 2 The specific surface area (S BET ) and pore size distribution of the ZnCo-1 catalytic material were detected by the N2 adsorption-desorption method. Figure 2 It shows that the N2 adsorption-desorption isotherm of the ZnCo-1 catalytic material is a type-IV isotherm, indicating that there are a large number of mesoporous structures on the ZnCo-1 catalytic material. The specific surface area of the ZnCo-1 catalytic material is 47.4 m 2 / g, the average pore size is 20.2 nm, and the pore volume is 0.24 cm 3 / g. The relatively large specific surface area and multi-level mesoporous structure of the ZnCo-1 catalytic material are beneficial to the exposure of active sites, accelerating mass transfer, the adsorption and activation of reactants, and thus improving the degradation effect of antibiotics.

[0023] Figure 3 are the XRD patterns of Co3O4, ZnO, ZnCo-0.5, ZnCo-1, ZnCo-2, and ZnCo-4 catalytic materials. As can be seen from Figure 3It can be seen that diffraction peaks of Co3O4 were observed at 2θ = 31.3°, 37.0°, 38.7°, 44.9°, 55.7°, 59.5° and 65.5°, which are respectively attributed to the (220), (311), (222), (400), (422), (511) and (440) crystal planes of Co3O4 (JCPDS #42-1467). Diffraction peaks of ZnO were observed at 2θ = 31.8°, 34.4°, 36.3°, 47.6°, 56.6° and 62.9°, which are respectively attributed to the (100), (002), (101), (102), (110) and (103) crystal planes of ZnO (JCPDS #36-1451). Diffraction peaks of Co3O4 and ZnO were observed in the XRD pattern of ZnCo-X. Compared with the XRD diffraction peaks of ZnO, the peak intensities of the diffraction peaks attributed to ZnO in ZnCo-X were significantly reduced, which may be due to the incorporation of some Zn species into the Co3O4 lattice to replace Co 2+ sites, forming a ZnCo2O4 spinel structure.

[0024] Figure 4 Figure 6 is the Fourier transform infrared (FTIR) spectra of Co3O4, ZnO, ZnCo-0.5, ZnCo-1, ZnCo-2 and ZnCo-4 catalytic materials. In the Co3O4 catalyst, the peaks at 675 cm -1 and 579 cm -1 are respectively attributed to the stretching vibration peaks of Co 2+ -O and Co 3+ -O in the spinel structure. At the same time, the peaks at 675 cm -1 and 579 cm -1 were also observed in ZnCo-X, which can be attributed to the stretching vibration peaks of Zn 2+ -O / Co 2+ -O and Co 3+ -O, indicating that the ZnCo-X catalyst has a ZnCo2O4 spinel structure.

[0025] Example 2 (The reaction is shown in Table 1, entry 1)

[0026] Under the reaction temperature condition of 25 °C, PMS with a set concentration of 0.2 g / L was added to a 250 mL beaker reactor containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5) to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by PMS alone was only 3.3%, indicating that the rate constant of PMS for tetracycline degradation ( k = 0.0237 min -1 ) is very small.

[0027] Example 3 (The reaction is shown in Table 1, entry 2)

[0028] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnO catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by the ZnO catalyst was 47.4%, and the rate constant of the ZnO catalytic material for tetracycline degradation was k = 0.387 min -1 .

[0029] Example 4 (The reaction is shown in Table 1, entry 3)

[0030] Under the reaction temperature condition of 25 °C, 0.1 g / L of Co3O4 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by Co3O4 was 23.9%, and the rate constant of the Co3O4 catalytic material for the degradation of tetracycline was k = 0.107 min -1 .

[0031] Example 5 (see Table 1, entry 4 for the reaction)

[0032] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 100%, and the rate constant of the ZnCo-1 catalytic material for the degradation of tetracycline was k = 1.217min -1 .

[0033]

[0034] Example 6 (see Table 2, entry 1 for the reaction)

[0035] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-0.5 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 84.3%, and the rate constant of the ZnCo-0.5 catalytic material for the degradation of tetracycline was k = 0.719 min -1 。

[0036] Example 7 (The reaction is shown in Table 2, entry 2)

[0037] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-2 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-2 was 100%, and the rate constant of the ZnCo-2 catalytic material for the degradation of tetracycline was k = 1.018 min -1 。

[0038] Example 8 (The reaction is shown in Table 2, entry 3)

[0039] Under the reaction temperature condition of 25 °C, 0.1 g / L of the ZnCo-4 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-4 was 100%, and the rate constant of the ZnCo-4 catalyst for the degradation of tetracycline was k = 0.369 min -1 。

[0040]

[0041] Example 9 (0.025 g / L of ZnCo-1 catalyst)

[0042] Under the reaction temperature condition of 25 °C, 0.025 g / L of the ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 50.6%.

[0043] Example 10 (0.05 g / L of ZnCo-1 catalyst)

[0044] Under the reaction temperature condition of 25 °C, 0.05 g / L of the ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 79.2%.

[0045] Example 11 (0.075 g / L of the ZnCo-1 catalyst)

[0046] Under the reaction temperature condition of 25 °C, 0.075 g / L of the ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 95.7%.

[0047] Example 12 (0.125 g / L of the ZnCo-1 catalyst)

[0048] Under the reaction temperature condition of 25 °C, 0.125 g / L of the ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 100%.

[0049] Implementation Case 13 (Reaction see Table 3, Items 1 - 5)

[0050] Under the reaction temperature condition of 25 °C, add 2 mg of tetracycline and 100 mL of deionized water to the reactor, then add the ZnCo-1 catalyst at a concentration of 0.1 g / L. After stirring for 30 min to reach the adsorption equilibrium, add PMS with a required concentration of 0.2 g / L to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, draw 2 mL of the reaction solution with a syringe, filter it using a 0.22 µm microporous membrane, and inject it into a test tube containing 2 mL of methanol. After shaking well, measure the concentration of tetracycline at a wavelength of 358 nm using a UV-visible spectrophotometer. When the reaction time is 5 min, it is found that the degradation rate of tetracycline by ZnCo-1 is 100%, and the leaching concentration of Co 2+ is 0.11 mg / L. When the catalyst is centrifuged and reused for the second time, the degradation rate of tetracycline is 100%, and the leaching concentration of Co 2+ is 0.09 mg / L. When the catalyst is centrifuged and reused for the third time, the degradation rate of tetracycline is 98.7%, and the leaching concentration of Co 2+ is 0.12 mg / L. When the catalyst is centrifuged and reused for the fourth time, the degradation rate of tetracycline is 97.6%, and the leaching concentration of Co 2+ is 0.08 mg / L. When the catalyst is centrifuged and reused for the fifth time, the degradation rate of tetracycline is 95.3%, and the leaching concentration of Co 2+ is 0.06 mg / L.

[0051]

[0052] Implementation Case 14 (Reaction see Table 4, Item 1, Degradation performance of sulfamethazine by ZnCo-1 catalyst)

[0053] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of sulfamethazine aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of sulfamethazine was measured using a UV-visible spectrophotometer at a wavelength of 265 nm. When the reaction time was 5 min, it was found that the degradation rate of sulfamethazine by ZnCo-1 was 100%, and the rate constant of the ZnCo-1 catalytic material for the degradation of sulfamethazine was k = 1.158 min -1 .

[0054] Example 15 (For the degradation performance of sulfamerazine by ZnCo-1 catalyst, see Table 4, entry 2)

[0055] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of sulfamerazine aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of sulfamerazine was measured using a UV-visible spectrophotometer at a wavelength of 267 nm. When the reaction time was 5 min, it was found that the degradation rate of sulfamerazine by ZnCo-1 was 100%, and the rate constant of the ZnCo-1 catalytic material for the degradation of sulfamerazine was k = 1.136 min -1 .

[0056] Example 16 (For the degradation performance of ciprofloxacin by ZnCo-1 catalyst, see Table 4, entry 3)

[0057] Under the reaction temperature of 25 °C, 0.1 g / L of ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of ciprofloxacin aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered through a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of ciprofloxacin was measured using a UV-visible spectrophotometer at a wavelength of 278 nm. When the reaction time was 5 min, it was found that the degradation rate of ciprofloxacin by ZnCo-1 was 100%, and the rate constant of the ZnCo-1 catalytic material for the degradation of ciprofloxacin was k = 1.048 min -1 .

[0058] Example 17 (For the degradation performance of oxytetracycline hydrochloride by ZnCo-1 catalyst, see Table 4, entry 4)

[0059] Under the reaction temperature of 25 °C, 0.1 g / L of ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of oxytetracycline hydrochloride aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered through a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of oxytetracycline hydrochloride was measured using a UV-visible spectrophotometer at a wavelength of 353 nm. When the reaction time was 5 min, it was found that the degradation rate of oxytetracycline hydrochloride by ZnCo-1 was 100%, and the rate constant of the ZnCo-1 catalytic material for the degradation of oxytetracycline hydrochloride was k = 1.029 min -1 .

[0060] Example 18 (For the degradation performance of florfenicol by ZnCo-1 catalyst, see Table 4, entry 5)

[0061] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-1 catalyst was added to a 250 mL beaker containing 100 mL of florfenicol aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of florfenicol was measured using a UV-visible spectrophotometer at a wavelength of 266 nm. When the reaction time was 5 min, it was found that the degradation rate of florfenicol by ZnCo-1 was 98.6%, and the rate constant of the ZnCo-1 catalytic material for the degradation of florfenicol was k = 0.954 min -1 .

[0062]

[0063] Example 19 (Effect of tert-butanol quencher on the degradation performance of ZnCo-1 catalyst for tetracycline)

[0064] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-1 catalyst and 4 mL of methanol were added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered using a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that with the addition of tert-butanol, the degradation rate of tetracycline by ZnCo-1 decreased to 45.2%, indicating that hydroxyl radicals (·OH) made a significant contribution to the degradation of tetracycline by ZnCo-1-activated PMS.

[0065] Example 20 (Effect of methanol quencher on the degradation performance of ZnCo-1 catalyst for tetracycline)

[0066] Under the reaction temperature of 25 °C, 0.1 g / L of ZnCo-1 catalyst and 4 mL of methanol were added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered through a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the degradation rate of tetracycline by ZnCo-1 was 40.8%. The results of the tert-butanol and methanol quenching experiments showed that both ·OH and SO4 ·- generated in the activation of PMS by ZnCo-1 contributed to the degradation of tetracycline. Compared with SO4 ·- , ·OH made a significant contribution to the degradation of tetracycline in the process of activating PMS by ZnCo-1.

[0067] Example 21 (Effect of L-histidine quencher on the degradation performance of ZnCo-1 catalyst for tetracycline)

[0068] Under the reaction temperature of 25 °C, 0.1 g / L of ZnCo-1 catalyst and 5 mg of L-histidine were added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered through a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that with the addition of L-histidine, the degradation rate of tetracycline by ZnCo-1 decreased to 36.1%, indicating that singlet oxygen ( 1 1O2) made a significant contribution to the degradation of tetracycline in the process of activating PMS by ZnCo-1.

[0069] Example 22 (Effect of p-benzoquinone quencher on the degradation performance of ZnCo-1 catalyst for tetracycline)

[0070] Under the reaction temperature condition of 25 °C, 0.1 g / L of ZnCo-1 catalyst and 5 mg of p-benzoquinone were added to a 250 mL beaker containing 100 mL of tetracycline aqueous solution (20 mg / L, pH = 6.5). After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered through a 0.22 µm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of tetracycline was measured using a UV-visible spectrophotometer at a wavelength of 358 nm. When the reaction time was 5 min, it was found that the addition of p-benzoquinone decreased the degradation rate of tetracycline by ZnCo-1 to 89.5%. The quenching experiment results of L-histidine and p-benzoquinone showed that during the process of ZnCo-1 activating PMS to degrade tetracycline 1 O2 and ·O2 - coexisted. Compared with ·O2 - , the generated 1 O2 in the reaction contributed more significantly to the degradation of tetracycline.

Claims

1. Application of a hollow tubular ZnCo-X spinel catalyst in degrading antibiotics, characterized in that, The ZnCo-X spinel catalyst with a hollow tubular structure was prepared for the first time by a grinding method with simple, rapid preparation steps, low energy consumption and less environmental pollution. For the preparation of ZnCo-X, where X = 1, the steps are as follows: Put 36 mmol of oxalic acid, 8 mmol of Co(NO3)2·6H2O and Zn(NO3)2·6H2O, with the molar ratio of Co(NO3)2·6H2O:Zn(NO3)2·6H2O = 1:X (X = 1), into a mortar. Grind the mixture with a pestle until it becomes a paste. Then transfer the paste-like mixture to a crucible and heat it in a muffle furnace from room temperature to 400 °C at a rate of 10 °C / min and hold for 3 h. After cooling, the catalytic material ZnCo-1 with a hollow tubular structure is obtained. Steps for the catalyst to activate PMS for the degradation of antibiotics in water: Under the reaction temperature condition of 25 °C, 0.1 g / L of the catalyst was added to a 250 mL beaker containing 100 mL of an aqueous solution of 20 mg / L antibiotic with a pH of 6.

5. After stirring for 30 min to reach the adsorption equilibrium, 0.2 g / L of PMS was added to the beaker to initiate the degradation reaction. At 10 s, 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min respectively, 2 mL of the reaction solution was extracted with a syringe, filtered through a 0.22 μm microporous membrane, and injected into a test tube containing 2 mL of methanol. After shaking well, the concentration of antibiotics in the water was measured using a UV-visible spectrophotometer under specific wavelength conditions. When ZnCo-1 was used as the catalyst, after 5 min of reaction, the degradation rates of sulfamethazine, sulfamethoxazole, ciprofloxacin, oxytetracycline hydrochloride, and florfenicol antibiotics in the water could reach 100%, 100%, 100%, 100%, and 98.6% respectively, and the rate constants were 1.158 min -1 , 1.136 min -1 , 1.048 min -1 , 1.029 min -1 , and 0.954 min -1 .

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