Catalyst for efficiently degrading fluoroquinolone antibiotics as well as preparation method and application of catalyst

Abstract

The invention relates to a catalyst for efficiently degrading fluoroquinolone antibiotics as well as a preparation method and application of the catalyst. The preparation method comprises the following steps: mixing ferrite and polyol in an organic solvent to react; and adding an aromatic compound containing at least two carboxyl groups, stirring, mixing, reacting, and filtering to obtain the catalyst. The catalyst obtained through the preparation method has the advantages of being excellent in catalytic performance, low in cost and environmentally friendly, and the preparation method is mild in reaction condition, simple in operation process, environmentally friendly and capable of being used for preparing the catalyst on a large scale.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic material preparation, and particularly relates to a catalyst for efficiently degrading fluoroquinolone antibiotics, a preparation method thereof, and an application thereof. Background Art

[0002] The Fenton reaction (Fe 2+ / Fe 3+ +H2O2) has become an advanced oxidation technology that has received attention because of its simple operation and mild reaction conditions. However, in practical applications, the Fenton method has disadvantages such as a narrow pH value range, easy generation of iron sludge leading to secondary pollution, and the inability to regenerate the used catalyst.

[0003] Metal-organic frameworks (MOFs) are crystalline porous materials with a periodic network structure formed by the self-assembly of metal ions or metal clusters and organic ligands, and have ultra-high and adjustable pore sizes and a large specific surface area. Among various reported MOFs, Fe-MOFs have extensive applications in catalysis. The Fe-O clusters in Fe-MOFs have strong absorption of visible light and are prone to generating photo-generated electrons and holes. The strong reducing ability of these photo-generated electrons can promote the valence state conversion of Fe, thereby enhancing the catalytic performance of the Fenton reaction for degrading pollutants.

[0004] CN115888843A discloses a preparation method of a photo-Fenton catalyst containing a two-component mixed metal, including: placing ScCl3·6H2O, FeCl3·6H2O, and H3BTC in a reaction vessel, then adding DMF, and ultrasonically stirring until the solution is clear to obtain a mixed solution; heating and reacting the mixed solution, naturally cooling after the reaction ends, and centrifuging to separate to obtain an orange deposit; washing the obtained orange powder with deionized water and ethanol, and drying the washed product; subjecting the dried product to vacuum activation to obtain the final product MIL-100(Sc, Fe) photo-Fenton catalyst. The prepared catalyst is a mesoporous material with 3D pores, has a very low impurity content, and has good crystallization performance, but the prepared catalyst highly depends on the pH value of the reaction solution.

[0005] CN116212953A discloses a preparation method of an iron-based metal-organic framework material photocatalyst, including: preparing a crystalline flexible porous pristine MIL-53 material, then preparing an acetic acid solution, and storing the acetic acid solution to be used at room temperature, and then slowly adding the acetic acid solution into the crystalline flexible porous pristine MIL-53 material using a metering device to prepare and synthesize D-2C-X and standard MIL-53(Fe), but the prepared catalyst still has the problem of highly depending on the pH value of the reaction solution.

[0006] In the above preparation method, the photocatalytic Fenton-like catalytic effect of the prepared Fe-MOFs highly depends on the pH value of the reaction solution. In traditional photocatalytic Fenton-like reactions, acids need to be added additionally to maintain the pH value of the reaction solution. Therefore, how to effectively improve the ability of photocatalytic Fenton-like degradation of organic pollutants under neutral pH conditions is a thorny problem in current scientific research. Obtaining a photocatalytic Fenton-like composite material with excellent catalytic performance, high stability, low cost, and environmental friendliness is of great significance for expanding the application scope of Fenton technology. Summary of the Invention

[0007] To solve the above technical problems, the present invention provides a catalyst for efficiently degrading fluoroquinolone antibiotics, its preparation method and application, which are used to solve the problem of low catalytic efficiency of iron-based metal-organic framework materials in photocatalytic Fenton-like reactions in the prior art. The catalyst of the present invention has the advantages of excellent catalytic performance, wide pH range, low cost, and environmental friendliness.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a preparation method of a catalyst for efficiently degrading fluoroquinolone antibiotics, and the preparation method includes: mixing and reacting a ferrous salt and a polyol in an organic solvent;

[0010] adding an aromatic compound containing at least two carboxyl groups, stirring and mixing for reaction, and then filtering to obtain the catalyst.

[0011] In the present invention, ferrous ions, as Lewis acids, can induce the esterification reaction between polyols and aromatic compounds containing at least two carboxyl groups, thereby occupying the positions where the carboxyl groups were originally complexed with ferrous ions, forming defects. The present invention prepares an amorphous metal-organic framework photocatalytic Fenton composite catalyst with a large specific surface area, many active sites, and strong photocatalytic Fenton catalytic ability by creating defects in the metal-organic framework. Compared with the conventional method, the preparation method of the present invention adopts a simple room-temperature mechanical stirring method to obtain an amorphous metal-organic framework photocatalytic Fenton composite catalyst, which improves the preparation efficiency and has the advantages of simple preparation conditions, easy control, readily available raw materials, low cost, etc., and is suitable for large-scale industrial preparation and application.

[0012] As a preferred technical solution of the present invention, the ferrous salt includes any one or at least two combinations of ferrous sulfate heptahydrate, ferrous chloride, ferrous acetate, or ferrous bromide. Typical but non-limiting examples of the combination are: the combination of ferrous sulfate heptahydrate and ferrous chloride, the combination of ferrous chloride and ferrous acetate, the combination of ferrous acetate and ferrous bromide, etc.

[0013] Preferably, the polyol includes any one or a combination of at least two of glycerol, xylitol, sorbitol, or mannitol. Typical but non-limiting examples of the combination are: the combination of glycerol and xylitol, the combination of xylitol and sorbitol, the combination of sorbitol and mannitol, etc.

[0014] Preferably, the organic solvent includes methanol.

[0015] Preferably, the aromatic compound containing at least two carboxyl groups includes any one of 1,3,5-benzenetricarboxylic acid, 5-hydroxyisophthalic acid, 5-aminoisophthalic acid, terephthalic acid, or 1,3,5-tris(4-carboxyphenyl)benzene.

[0016] As a preferred technical solution of the present invention, the volume ratio of the polyol to the organic solvent is 1:(0.5 - 20), such as 1:0.5, 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, 1:12, 1:15, 1:18, 1:20, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0017] Preferably, the molar ratio of the ferrous salt to the aromatic compound containing at least two carboxyl groups is (2 - 5):(1 - 2), such as 2:1, 2:1.5, 2:2, 3:1, 3:2, 4:1, 4:2, 5:1, 5:2, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0018] As a preferred technical solution of the present invention, the temperature of the mixed reaction is 30 - 80 °C, such as 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0019] Preferably, the temperature of the stirring and mixing reaction is 30 - 50 °C, such as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0020] The stirring rate of the stirring and mixing reaction is 200 - 400 r / min, such as 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, etc., but is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0021] The time of the stirring and mixing reaction is 6 to 24 h, such as 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0022] As a preferred technical solution of the present invention, after filtering the stirring and mixing reaction, it further includes vacuum drying treatment of the obtained solid.

[0023] Preferably, the temperature of the vacuum drying is 50 to 80 °C, such as 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0024] The time of the vacuum drying is 10 to 15 h, such as 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0025] As a preferred technical solution of the present invention, the preparation method includes: mixing and reacting ferrous sulfate heptahydrate and glycerol in methanol at 30 to 80 °C; adding 1,3,5-benzenetricarboxylic acid, and carrying out a stirring and mixing reaction at 30 to 50 °C for 6 to 24 h, the stirring speed is 200 to 400 r / min, after filtering, carrying out vacuum drying treatment at 50 to 80 °C for 10 to 15 h to obtain the catalyst;

[0026] Among them, the volume ratio of the glycerol to the methanol is 1:(0.5 to 20); the molar ratio of the ferrous sulfate heptahydrate to the 1,3,5-benzenetricarboxylic acid is (2 to 5):(1 to 2).

[0027] In the second aspect, the present invention provides a catalyst for efficiently degrading fluoroquinolone antibiotics, and the catalyst is prepared by using the preparation method described in the first aspect.

[0028] In the third aspect, the present invention provides a method for degrading fluoroquinolone antibiotics in a photo-Fenton system, and the method is carried out by using the catalyst described in the second aspect, and the method includes:

[0029] (1) Adding the catalyst into an aqueous solution containing fluoroquinolone antibiotics for dark adsorption-desorption equilibrium to obtain a reaction solution;

[0030] (2) Transferring the reaction solution to a photoreaction device, adding an oxidant, and carrying out a photo-Fenton reaction under visible light with a wavelength greater than 420 nm.

[0031] As a preferred technical solution of the present invention, the fluoroquinolone antibiotics include any one or a combination of at least two of orbifloxacin, danofloxacin, enrofloxacin, fleroxacin, gatifloxacin, lomefloxacin, marbofloxacin, moxifloxacin, norfloxacin, pefloxacin, prulifloxacin, sparfloxacin, ofloxacin or levofloxacin. Typical but non-limiting examples of the combination are: the combination of orbifloxacin and danofloxacin, the combination of enrofloxacin and fleroxacin, the combination of gatifloxacin and lomefloxacin, the combination of marbofloxacin and moxifloxacin, the combination of norfloxacin and pefloxacin, the combination of prulifloxacin and sparfloxacin, the combination of ofloxacin and levofloxacin, etc.

[0032] As a preferred technical solution of the present invention, the time for the light absorption-desorption equilibrium in step (1) is at least 1 h, such as 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0033] Preferably, the concentration of the catalyst is 0.05 - 0.5 g / L, such as 0.05 g / L, 0.1 g / L, 0.2 g / L, 0.3 g / L, 0.4 g / L, 0.5 g / L, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0034] Preferably, the pH of the reaction solution is 3 - 11, such as 3, 4, 5, 6, 7, 8, 9, 10, 11, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0035] Preferably, the concentration of the oxidant in step (2) is 1.0 - 3.0 g / L, such as 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0036] The oxidant includes any one or a combination of at least two of hydrogen peroxide, sodium persulfate, potassium persulfate, calcium oxide or magnesium oxide. Typical but non-limiting examples of the combination are: the combination of hydrogen peroxide and sodium persulfate, the combination of sodium persulfate and potassium persulfate, the combination of potassium persulfate and calcium oxide, the combination of calcium oxide and magnesium oxide, etc.

[0037] Preferably, the time for the photo-Fenton reaction is at least 90 min, such as 90 min, 100 min, 110 min, 120 min, 130 min, 140 min, 150 min, etc., but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0038] Compared with the prior art, the present invention has at least the following beneficial effects:

[0039] (1) By creating defects on the metal-organic framework, the present invention increases the specific surface area of the material and provides more catalytic sites. At the same time, the prepared material can weaken the dependence of traditional Fenton catalysts on pH, enabling the reaction to occur under milder acidity conditions, and effectively increasing the active sites in the pores, thereby enhancing its catalytic performance.

[0040] (2) Compared with conventional methods, the preparation method of the present invention uses a simple mechanical stirring method to prepare an amorphous metal-organic framework photocatalytic Fenton composite catalyst, improving the preparation efficiency. It has the advantages of short preparation cycle, low energy consumption, simple process, convenient operation, and low cost, is suitable for large-scale preparation, and is conducive to industrial application.

[0041] (3) The catalyst preparation process of the present invention has the advantages of simple preparation process, easy operation, readily available raw materials, and low cost. Description of the Drawings

[0042] Figure 1 is the scanning electron microscope (SEM) image of the catalyst prepared in Example 1.

[0043] Figure 2 is the transmission electron microscope (TEM) image of the catalyst prepared in Example 1.

[0044] Figure 3 is the MAPPING spectrum of the catalyst prepared in Example 1.

[0045] Figure 4 is the X-ray photoelectron spectroscopy (XPS) spectrum of the catalyst prepared in Example 1.

[0046] Figure 5 is the X-ray diffraction (XRD) spectrum of the catalyst prepared in Example 1.

[0047] Figure 6 is the Fourier transform infrared (FTIR) spectrum of the catalyst prepared in Example 1.

[0048] Figure 7 is the electron spin resonance (ESR) spectrum of the catalyst prepared in Example 1.

[0049] Figure 8 is the graph of the removal rate of moxifloxacin with different catalyst dosages in Application Example 1 of the present invention.

[0050] Figure 9 is the graph of the removal rate of moxifloxacin with different oxidant dosages in Application Example 2 of the present invention.

[0051] Figure 10It is the graph of the removal rate of moxifloxacin at different initial pH values in Application Example 3 of the present invention.

[0052] Figure 11 It is the graph of the removal rate of moxifloxacin with different quenchers in Application Example 4 of the present invention.

[0053] Figure 12 It is the graph of the removal rate of moxifloxacin in different natural waters by the catalyst in Application Example 5 of the present invention.

[0054] Figure 13 It is the graph of the removal rate of 14 fluoroquinolone antibiotics by the catalyst in Application Example 6 of the present invention.

[0055] Figure 14 It is the graph of the removal rate of moxifloxacin by the catalyst in Application Example 7 and Comparative Application Example 1 of the present invention compared with the traditional catalyst. Detailed implementation manners

[0056] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation manners. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the protection of the rights of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0057] Example 1

[0058] This example provides a preparation method of a catalyst for efficiently degrading fluoroquinolone antibiotics, and the preparation method includes:

[0059] Mix 0.556 g of FeSO4·7H2O with 10 mL of glycerol in 70 mL of methanol at 30 °C for reaction; add 0.282 g of 1,3,5-benzenetricarboxylic acid, stir and mix for reaction at 30 °C for 10 h, the stirring speed is 200 r / min, after filtration, carry out vacuum drying treatment at 60 °C for 12 h to obtain the catalyst.

[0060] The scanning electron microscope (SEM), transmission electron microscope (TEM), MAPPING spectrum, X-ray photoelectron spectroscopy (XPS) spectrum, X-ray diffraction (XRD) spectrum, Fourier transform infrared (FTIR) spectrum, and electron spin resonance (ESR) spectrum of the prepared catalyst were tested, as shown respectively in Figure 1 - 7 as follows.

[0061] Example 2

[0062] This example provides a preparation method of a catalyst for efficiently degrading fluoroquinolone antibiotics, and the preparation method includes:

[0063] Mix 0.440 g of FeBr₂ with 30 mL of glycerol in 60 mL of methanol at 50 °C for reaction; add 0.249 g of 5-hydroxyisophthalic acid, stir and mix for reaction at 40 °C for 6 h, with the stirring speed being 300 r / min. After filtration, conduct vacuum drying treatment at 50 °C for 10 h to obtain the catalyst.

[0064] Example 3

[0065] This example provides a preparation method of a catalyst for efficiently degrading fluoroquinolone antibiotics, and the preparation method includes:

[0066] Mix 0.366 g of Fe(CH₃COO)₂ with 4 mL of glycerol in 80 mL of methanol at 80 °C for reaction; add 0.282 g of 1,3,5-benzenetricarboxylic acid, stir and mix for reaction at 50 °C for 24 h, with the stirring speed being 400 r / min. After filtration, conduct vacuum drying treatment at 80 °C for 15 h to obtain the catalyst.

[0067] Comparative Example 1

[0068] This comparative example provides a traditional photocatalyst MIL-100(Fe).

[0069] Application Example 1

[0070] This application example provides a method for degrading fluoroquinolone antibiotics in a photo-Fenton system. The method is carried out using the catalyst prepared in Example 1, and the method includes:

[0071] (1) Add the catalysts with different concentrations in Example 1 to 30 mL of moxifloxacin aqueous solution (pH = 7, moxifloxacin content is 200 mg·L -1 ) for dark adsorption-desorption equilibrium for 1 h to obtain the reaction solution;

[0072] (2) Transfer the reaction solution to a photoreaction device, add 55.5 mg of H₂O₂ solution, and carry out photo-Fenton reaction under visible light with a wavelength greater than 420 nm for 90 min.

[0073] The degradation effect of the catalyst is tested using an ultraviolet-visible spectrophotometer, and the test results are as Figure 8 shown. The different catalyst concentrations and the moxifloxacin removal rates are shown in Table 1.

[0074] Table 1

[0075] <![CDATA[Catalyst concentration (g·L -1 )]]> 0.083 0.167 0.333 0.667 1.00 Removal Rate (%) 85.92 96.51 96.52 95.09 94.66

[0076] Application Example 2

[0077] This application example provides a method for degrading fluoroquinolone antibiotics in a photo-Fenton system. The method is carried out using the catalyst prepared in Example 2, and the method includes:

[0078] (1) Add 5 mg of the catalyst in Example 2 to 30 mL of moxifloxacin aqueous solution (pH = 7, moxifloxacin content is 200 mg·L -1 ) and carry out dark adsorption-desorption equilibrium for 1 h to obtain a reaction solution;

[0079] (2) Transfer the reaction solution to a photoreaction device, add different masses of H2O2 to make the reaction system have different concentrations of H2O2 solution, and carry out photo-Fenton reaction for 90 min under visible light with a wavelength greater than 420 nm.

[0080] The degradation effect of the catalyst is tested using an ultraviolet-visible spectrophotometer, and the test results are as Figure 9 shown. The different H2O2 concentrations and moxifloxacin removal rates are shown in Table 2.

[0081] Table 2

[0082] <![CDATA[H2O2 concentration (g·L -1 )]]> 1.11 1.48 1.85 2.22 2.59 Removal Rate (%) 93.31 95.45 96.51 95.40 94.86

[0083] Application Example 3

[0084] This application example provides a method for degrading fluoroquinolone antibiotics in a photo-Fenton system. The method is carried out using the catalyst prepared in Example 3, and the method includes:

[0085] (1) Add 5 mg of the catalyst in Example 3 to 30 mL of moxifloxacin aqueous solution (moxifloxacin content is 200 mg·L -1 ) and carry out dark adsorption-desorption equilibrium for 1 h, and adjust the pH of the reaction solution to 3, 5, 7, 9, and 11 respectively to obtain a reaction solution;

[0086] (2) Transfer the reaction solution to a photoreaction device, add 55.5 mg of H2O2, and carry out photo-Fenton reaction for 90 min under visible light with a wavelength greater than 420 nm.

[0087] The degradation effect of the catalyst is tested using an ultraviolet-visible spectrophotometer, and the test results are as Figure 10 shown. The different pH values and moxifloxacin removal rates are shown in Table 3.

[0088] Table 3

[0089] pH 3 5 7 9 11 Removal Rate (%) 97.35 97.43 96.51 93.46 65.04

[0090] Application Example 4

[0091] This application example provides a method for degrading fluoroquinolone antibiotics in a photo-Fenton system. The method is carried out using the catalyst prepared in Example 1, and the method includes:

[0092] (1) Add 5 mg of the catalyst from Example 1 to 30 mL of moxifloxacin aqueous solution (pH = 7, moxifloxacin content is 200 mg·L -1 ), and then add different quenchers, namely: ammonium oxalate (AO) to quench holes (h + ), silver nitrate (AgNO3) to quench electrons (e - ), tert-butanol (TBA) to quench hydroxyl radicals (·OH), p-benzoquinone (BQ) to quench superoxide radicals (·O2 - ), L-histidine (L-His) to quench singlet oxygen (1O 2 ), and carry out light-shielded adsorption-desorption equilibrium for 1 h to obtain a reaction solution;

[0093] (2) Transfer the reaction solution to a photoreaction device, add 55.5 mg of H2O2, and carry out a photo-Fenton reaction under visible light with a wavelength greater than 420 nm for 90 min.

[0094] The degradation effect of the catalyst is tested using an ultraviolet-visible spectrophotometer, and the test results are as Figure 11 shown, and the removal rates of moxifloxacin with different quenchers are shown in Table 4.

[0095] Table 4

[0096] Quencher Ammonium Oxalate Silver Nitrate tert - Butyl Alcohol p - Benzoquinone L - Histidine Removal Rate (%) 65.25 60.53 53.33 71.93 76.75

[0097] Application Example 5

[0098] This application example provides a method for degrading fluoroquinolone antibiotics in a photo-Fenton system. The method is carried out using the catalyst prepared in Example 1, and the method includes:

[0099] (1) Add 5 mg of the catalyst from Example 1 to 30 mL of moxifloxacin solutions in different water bodies (pH = 7, moxifloxacin content is 200 mg·L -1 ) and carry out light-shielded adsorption-desorption equilibrium for 1 h to obtain a reaction solution;

[0100] (2) Transfer the reaction solution to a photoreaction device, add 55.5 mg of H2O2, and carry out a photo-Fenton reaction under visible light with a wavelength greater than 420 nm for 90 min.

[0101] The degradation effect of the catalyst is tested using an ultraviolet-visible spectrophotometer, and the test results are as Figure 12 shown, and the removal rates of moxifloxacin in different water bodies are shown in Table 5.

[0102] Table 5

[0103] Water Body Seawater Rainwater Reservoir Water Ultra - Pure Water Removal Rate ((%)) 28.71 96.28 62.10 96.51

[0104] Among them, seawater is taken from Rizhao, Shandong; rainwater is taken from Shangzhuang Town, Haidian District, Beijing on September 8, 2024; and reservoir water is taken from Shangzhuang Reservoir in Haidian District, Beijing.

[0105] Application Example 6

[0106] This application example provides a method for degrading fluoroquinolone antibiotics using a photo-Fenton system, the method being carried out using the catalyst prepared in Example 1, and the method comprising:

[0107] (1) 5 mg of the catalyst of Example 1 was added to 30 mL of an aqueous solution containing fluoroquinolone antibiotics (pH = 7, fluoroquinolone antibiotic content of 200 mg / L -1 ) was subjected to light-proof adsorption-desorption equilibrium for 1 h to obtain a reaction solution; wherein the fluoroquinolone antibiotics were orbifloxacin (ORB), danofloxacin (DLX), enrofloxacin (ENR), fleroxacin (FLE), gatifloxacin (GAT), lomefloxacin (LOM), marbofloxacin (MAR), moxifloxacin (MOX), norfloxacin (NOR), pefloxacin (PEF), prulifloxacin (PUR), sparfloxacin (SPX), ofloxacin (OFX), and levofloxacin (LVX);

[0108] (2) The reaction solution was transferred to a photoreaction apparatus, 55.5 mg of H2O2 was added, and the photo-Fenton reaction was carried out under visible light with a wavelength greater than 420 nm for 90 min.

[0109] The degradation effect of the catalyst was tested using a UV-visible spectrophotometer. Figure 13 The removal rates of different fluoroquinolone antibiotics by the catalysts are shown in Table 6.

[0110] Table 6

[0111] Antibiotic ORB DLX ENR FLE GAT LOM MAR Removal Rate (%) 87.81 93.81 81.38 85.69 89.88 85.41 96.69 Antibiotic MOX NOR PEF PUR SPX OFL LVX Removal Rate (%) 96.51 91.53 89.17 92.20 90.24 93.57 93.17

[0112] Application Example 7 and Comparative Application Example 1

[0113] This application example provides a method for degrading fluoroquinolone antibiotics using a photo-Fenton system, wherein the method is performed using the catalyst prepared in Example 1 (Application Example 7) and the catalyst prepared in Comparative Example 1 (Comparative Application Example 1), respectively, and the method comprises:

[0114] (1) 5 mg of the catalyst of Example 1 and 5 mg of the catalyst of Comparative Example 1 were added to 30 mL of a moxifloxacin aqueous solution (pH = 7, moxifloxacin content of 200 mg / L) respectively. -1)Perform light-avoiding adsorption-desorption equilibrium for 1 h to obtain a reaction solution;

[0115] (2) Transfer the reaction solution to a photoreaction device, add 55.5 mg of H2O2, and carry out a photo-Fenton reaction for 90 min under visible light with a wavelength greater than 420 nm.

[0116] The degradation effect of the catalyst was tested using a UV-visible spectrophotometer, and the test results are as Figure 14 shown. The removal rates of moxifloxacin by the catalyst of Example 1 and the catalyst of Comparative Example 1 are shown in Table 7.

[0117] Table 7

[0118] Catalyst Example 1 Comparative Example 1 Removal Rate (%) 96.51 13.77

[0119] Test results

[0120] (1) Through Figure 1 It can be seen that the catalyst (GM-100) prepared in Example 1 presents an amorphous coral-like structure with a rough surface, which is beneficial to increasing the reaction active sites.

[0121] Through Figure 2 It can be known that the overall surface of GM-100 is rough and the edges are uneven, showing an amorphous structure.

[0122] Through Figure 3 It can be seen that the three elements of carbon, oxygen, and iron in GM-100 are evenly distributed.

[0123] Through Figure 4 It can be known that from the O1s spectrum, compared with the traditional photocatalyst MIL-100(Fe), GM-100 has an obvious absorption peak at 286.3 eV, indicating that there is a certain C-O-C structure in the material structure.

[0124] Through Figure 5 It can be seen that compared with the traditional photocatalyst MIL-100(Fe), GM-100 has no obvious characteristic peaks, only a relatively wide peak, which is a characteristic of amorphous materials.

[0125] Through Figure 6 It can be seen that compared with the traditional photocatalyst MIL-100(Fe), GM-100 has an obvious strong absorption peak at 1200-1000 nm, which belongs to the typical vibration of ester single bonds, indicating that the material contains a certain C-O-C structure, which is also consistent with the results of XPS.

[0126] Figure 7The electron spin resonance (ESR) spectrum of GM-100 was shown, which elaborated the basic mechanism of the degradation of moxifloxacin by GM-100. The results showed that three free radicals could be generated by GM-100 in water: 1O 2 , ·O2 - and ·OH. When irradiated by light, GM-100 was excited by natural light to generate photo-generated e - and h + . e - reacted with dissolved oxygen in water to produce 1O 2 , ·O2 - and ·OH. These active free radicals had strong oxidation ability and could degrade fluoroquinolone antibiotics.

[0127] (2) Application Example 1 tested the degradation ability of different catalyst concentrations on moxifloxacin antibiotics, and the results are shown in Figure 8 and Table 1. It can be seen from the test results that at the same time, when the catalyst dosage increased from 0.083 g·L -1 to 0.167 g·L -1 , the removal rate of moxifloxacin increased from 85.92% to 96.51%; when the catalyst dosage increased to 0.333 g·L -1 , the removal rate was almost the same. When the catalyst dosage was further increased to 1.00 g·L -1 , the removal rate of moxifloxacin decreased slightly. Therefore, the catalyst prepared in the present invention could achieve a removal rate of more than 90% in the range of 0.167 g·L -1 to 1.00 g·L -1 .

[0128] (3) Application Example 2 tested the influence of different oxidant concentrations on the removal rate of moxifloxacin antibiotics, and the results are shown in Figure 9 and Table 2. It can be seen from the test results that when the concentration of H2O2 increased from 1.11 g·L -1 to 1.85 g·L -1 , the removal rate of moxifloxacin increased from 93.31% to 96.51% within 90 min; when the concentration of H2O2 continued to increase to 2.22 g·L -1 , the removal rate of moxifloxacin decreased slightly within 90 min. When the concentration of H2O2 was further increased to 2.59 g·L -1 , the removal rate of moxifloxacin continued to decrease within 90 min. Therefore, the oxidant in the present invention could achieve a removal rate of more than 90% in the range of 1.11 g·L -1 to 2.59 g·L -1 .

[0129] (4) Application Example 3 tested the effect of different pH values in the water sample on the removal rate of moxifloxacin antibiotic, and the results are as Figure 10 shown in Table 3. It can be seen from the test results that when pH ≤ 7, the removal rate of moxifloxacin by the catalyst can reach more than 96%. Among them, when pH = 5, the removal rate of moxifloxacin by the catalyst reached 97.43%. Compared with the neutral condition, when pH = 9, the removal effect of the catalyst on moxifloxacin decreased slightly, but still remained above 93%. When the pH value further increased to 11, the removal effect of the catalyst on moxifloxacin decreased significantly. Therefore, the catalyst of the present invention has a good removal rate for moxifloxacin within the common wastewater pH range (pH 6-9).

[0130] (5) Application Example 4 tested the effect of the catalyst prepared by the present invention on the removal rate of moxifloxacin antibiotic after using different quenchers, and the results are as Figure 11 shown in Table 4. It can be seen from the test results that holes (h + ), electrons (e - ), hydroxyl radicals (·OH), superoxide radicals (·O2 - ), and singlet oxygen (1O 2 ) all participated in the degradation process of moxifloxacin. Among them, the effect of the degradation reaction was the most affected after the hydroxyl radicals (·OH) were quenched, and the final removal rate was only 53.33%, indicating that the hydroxyl radicals played a dominant role in the degradation reaction. Therefore, the catalyst of the present invention can generate five kinds of free radicals during the reaction process, and through the combined action of the five kinds of free radicals, moxifloxacin can be rapidly degraded.

[0131] (6) Application Example 5 tested the effect of the catalyst prepared by the present invention on the removal rate of moxifloxacin antibiotic in different water bodies, and the results are as Figure 12 shown in Table 5. It can be seen from the test results that the removal rate of moxifloxacin in seawater and reservoir water decreased compared with that in ultrapure water. This is because various organic and inorganic components in real water bodies occupy the active sites on the catalyst surface, not only acting as scavengers of hydroxyl radicals, but also competing with reactive species, thus reducing the efficiency of photocatalytic Fenton degradation of moxifloxacin in natural wastewater; while in rainwater, the degradation effect was hardly affected. Generally speaking, the catalyst prepared by the present invention can effectively remove moxifloxacin in environmental water bodies by the photocatalytic Fenton method.

[0132] (7) Application Example 6 tested the effect of the catalyst prepared by the present invention on the removal rate of different fluoroquinolone antibiotics, and the results are as Figure 13As shown in Table 6. It can be seen from the test results that the catalyst prepared by the present invention can achieve a removal rate of more than 80% for most fluoroquinolone antibiotics under the preferred conditions, and some can reach more than 90%. Among them, the removal rate of enrofloxacin is the lowest, at 81.38%; the removal rate of marbofloxacin is the highest, at 96.69%. Thus, it can be seen that the catalyst prepared by the present invention has a good removal rate for the vast majority of fluoroquinolone antibiotics.

[0133] (8) Application Example 7 and Comparative Application Example 1 tested the influence of the catalyst prepared in Example 1 of the present invention and the catalyst of Comparative Example 1 on the removal rate of moxifloxacin antibiotic, and the results are as Figure 14 shown in Table 7. It can be seen from the test results that the catalyst prepared in Example 1 can achieve a removal rate of more than 96% for moxifloxacin under the preferred conditions, while the traditional catalyst MIL-100(Fe) of Comparative Example 1 has almost no removal effect on moxifloxacin under the same conditions. Thus, it can be seen that the catalyst prepared by the present invention has the advantage of being able to react under neutral conditions compared with the traditional photo-Fenton catalyst.

[0134] In summary, the present invention provides a catalyst for efficiently degrading fluoroquinolone antibiotics, its preparation method and application. By creating defects on the metal-organic framework, a modified metal-organic framework photo-Fenton composite material with a large specific surface area, many active sites and strong photo-Fenton catalytic ability is prepared. At the same time, the formed material can weaken the dependence of the traditional Fenton catalyst on pH, can react under milder acidity conditions, and can effectively increase the active sites in the pores, thereby enhancing its catalytic performance. In addition, the preparation method of the present invention has the advantages of short preparation period, low energy consumption, simple process, convenient operation, low cost, etc., is suitable for large-scale preparation, and is conducive to industrial application.

[0135] The applicant declares that the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A preparation method of a catalyst for efficiently degrading fluoroquinolone antibiotics, characterized in that, The preparation method includes: After mixing and reacting ferrous salt and polyol in an organic solvent; Adding an aromatic compound containing at least two carboxyl groups, stirring and mixing, reacting, and then filtering to obtain the catalyst.

2. The preparation method according to claim 1, characterized in that, The ferrous salt includes any one or a combination of at least two of ferrous sulfate heptahydrate, ferrous chloride, ferrous acetate, or ferrous bromide; The polyol includes any one or a combination of at least two of glycerol, xylitol, sorbitol, or mannitol; the organic solvent includes methanol; The aromatic compound containing at least two carboxyl groups includes any one of 1,3,5-benzenetricarboxylic acid, 5-hydroxyisophthalic acid, 5-aminoisophthalic acid, terephthalic acid, or 1,3,5-tris(4-carboxyphenyl)benzene.

3. The preparation method according to claim 1, characterized in that, The volume ratio of the polyol to the organic solvent is 1:(0.5 - 20); the molar ratio of the ferrous salt to the aromatic compound containing at least two carboxyl groups is (2 - 5):(1 - 2).

4. The preparation method according to claim 1, wherein The temperature of the mixing reaction is 30 - 80 °C; The temperature of the stirring and mixing reaction is 30 - 50 °C; the stirring rate of the stirring and mixing reaction is 200 - 400 r / min; the time of the stirring and mixing reaction is 6 - 24 h.

5. The preparation method according to claim 1, wherein Filtering after the stirring and mixing reaction further includes performing vacuum drying treatment on the obtained solid; the temperature of the vacuum drying is 50 - 80 °C; the time of the vacuum drying is 10 - 15 h.

6. The preparation method according to claim 1, characterized in that, The preparation method includes: Mixing and reacting ferrous sulfate heptahydrate and glycerol in methanol at 30 - 80 °C; adding 1,3,5-benzenetricarboxylic acid, stirring and mixing at 30 - 50 °C for 6 - 24 h, with the stirring speed of 200 - 400 r / min, and after filtering, performing vacuum drying treatment at 50 - 80 °C for 10 - 15 h to obtain the catalyst; Wherein, the volume ratio of the glycerol to the methanol is 1:(0.5 - 20); the molar ratio of the ferrous sulfate heptahydrate to the 1,3,5-benzenetricarboxylic acid is (2 - 5):(1 - 2).

7. A catalyst for efficiently degrading fluoroquinolone antibiotics, characterized in that, The catalyst is prepared by the preparation method described in any one of claims 1 - 6.

8. A method for degrading fluoroquinolone antibiotics by a photo-Fenton system, characterized in that, The method is carried out using the catalyst described in claim 7, and the method includes: (1) Adding the catalyst to an aqueous solution of a fluoroquinolone antibiotic for light-shielded adsorption-desorption equilibrium to obtain a reaction solution; (2) Transferring the reaction solution to a photoreaction device, adding an oxidant, and carrying out a photo-Fenton reaction under visible light with a wavelength greater than 420 nm.

9. The method according to claim 8, wherein The fluoroquinolone antibiotics include any one or a combination of at least two of orbifloxacin, danofloxacin, enrofloxacin, fleroxacin, gatifloxacin, lomefloxacin, marbofloxacin, moxifloxacin, norfloxacin, pefloxacin, prulifloxacin, sparfloxacin, ofloxacin, or levofloxacin.

10. The method according to claim 8, wherein The time of the light-shielded adsorption-desorption equilibrium in step (1) is at least 1 h; the concentration of the catalyst is 0.05 - 0.5 g / L; the pH of the reaction solution is 3 - 11; The concentration of the oxidant described in step (2) is 1.0 to 3.0 g / L; the oxidant includes any one or a combination of at least two of hydrogen peroxide, sodium persulfate, potassium persulfate, calcium oxide, or magnesium oxide; the time of the photo-Fenton reaction is at least 90 min.

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