Method for degrading antibiotics in water body by using iron-doped zsm5 zeolite to activate hydrogen peroxide

Abstract

The application discloses a method for degrading antibiotics in water by using iron-doped ZSM5 zeolite to activate hydrogen peroxide, wherein the iron-doped zeolite is prepared by sequentially mixing sodium metaaluminate, tetrapropylammonium hydroxide, water, tetraethoxysilane and an iron source, and then performing hydrothermal reaction and calcination. The iron-doped ZSM5 zeolite has the advantages of high catalytic activity and good stability, and can generate a large amount of active oxygen species when used to activate hydrogen peroxide, so that the active oxygen species can be used to efficiently degrade antibiotics in wastewater. In particular, the Fe species is hardly leached during use, and the method has the advantages of good degradation effect, green environmental protection, wide pH application range, magnetic recovery, good reusability, low cost and the like, and can be widely used for treating different types of antibiotic wastewater, and has high use value and good application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of water treatment and relates to a method for degrading antibiotics in water by utilizing iron-doped ZSM5 zeolite to activate hydrogen peroxide. Background Art

[0002] Over 70% of the Earth's surface is covered by water, yet the water resources available for human use are relatively scarce. This situation is partly due to the continuous discharge of pollutants into water bodies that exceed the environment's self-purification capacity, including a considerable proportion of antibiotics. Antibiotics are widely used in the fields of human animal husbandry, health care, agriculture, and other fields. In particular, high concentrations of tetracycline pollutants discharged from veterinary sources may cause high levels of related antibiotic resistance genes (ARGs) to spread in the environment, posing a risk to human health. Therefore, the serious excess of antibiotics in the water environment, especially antibiotics represented by tetracycline, urgently requires efficient and convenient treatment processes to reduce the risk of related ARG transmission.

[0003] Advanced oxidation processes (AOPs) are chemical treatment technologies characterized by high catalytic efficiency and environmental friendliness. Among AOPs, the Fenton reaction is a representative technology, characterized by its strong oxidative capacity and simple operating conditions, making it an excellent choice for treating refractory pollutants, particularly antibiotics. However, the classic homogeneous Fenton reaction has several limitations, such as a narrow reaction pH range and difficulty in catalyst separation and recovery, which can lead to secondary pollution. Heterogeneous Fenton reactions can effectively address these issues, making the selection of an appropriate catalyst crucial for achieving efficient antibiotic degradation. Existing heterogeneous catalysts reported for Fenton-based removal of antibiotic contaminants from water can be primarily categorized as metal oxides, nano-zero-valent metal-based catalysts, and supported catalysts. Supported catalysts are relatively inexpensive and more readily applicable for large-scale wastewater treatment. Zeolites, as support materials with high cation exchange capacity, ease of availability, and environmental friendliness, are widely used in advanced oxidation processes. Crucially, zeolites remain stable even in the presence of highly oxidizing reactive oxygen species such as hydroxyl radicals (·OH). However, the zeolite-based catalysts currently prepared either have the problem of reduced catalytic activity due to the agglomeration of metal species or the problem of secondary pollution caused by the leaching of metal species. It can be seen that when designing widely used zeolite-based catalysts, it is necessary to maximize the activity of metal sites and minimize the leakage of metal ions to achieve easy recycling and maintain the stability of catalytic activity. This is very important and also has important significance for promoting the practical application of zeolite-based catalysts. In addition, the use of zeolites for the efficient degradation of antibiotic pollution is still in the exploratory stage and its application potential needs further research and exploration. Therefore, the development of a new zeolite-based catalyst with high catalytic activity, low metal ion leaching rate, good stability and easy recovery is of great significance for the efficient activation of hydrogen peroxide and the efficient degradation of antibiotic pollutants in water bodies. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies of the existing technology and provide a method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite, which has high degradation efficiency, less metal leaching, good recycling effect and is green and environmentally friendly.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite, wherein the iron-doped ZSM5 zeolite is used as a catalyst to activate hydrogen peroxide to degrade antibiotic wastewater; the iron-doped ZSM5 zeolite is prepared by sequentially mixing sodium metaaluminate, tetrapropylammonium hydroxide, water, tetraethoxysilane, and an iron source, subjecting the mixture to a hydrothermal reaction and calcination, wherein the iron source is at least one of ferrous acetylacetonate, ferric acetylacetonate, or ferric nitrate.

[0007] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, and the preparation steps of the iron-doped ZSM5 zeolite include:

[0008] S1. Mix sodium metaaluminate, tetrapropylammonium hydroxide and water, and stir to obtain a mixed solution A;

[0009] S2, adding tetraethoxysilane to the mixed solution A, stirring to obtain a mixed solution B;

[0010] S3, adding an iron source to the mixed solution B and stirring to obtain a mixed solution C;

[0011] S4, performing a hydrothermal reaction on the mixed solution C to obtain a hydrothermal reaction product;

[0012] S5. calcining the hydrothermal reaction product to obtain iron-doped ZSM5 zeolite.

[0013] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, wherein the mass ratio of tetraethoxysilane, sodium metaaluminate, tetrapropylammonium hydroxide, iron source and water is 8.32:0.07286:13.01:0.5:15.45.

[0014] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved. In step S4, the reaction temperature of the hydrothermal reaction is 140° C. to 190° C., and the reaction time of the hydrothermal reaction is 60 h to 108 h.

[0015] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved. In step S5, the calcination temperature is 500°C to 650°C, the calcination heating rate is 1°C / min to 6°C / min, and the calcination time is 2h to 7h.

[0016] The above method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite is further improved in that, in step S1, the stirring time is 1 hour to 4 hours.

[0017] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved in that, in step S2, the stirring time is 4 hours to 7 hours.

[0018] The above method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite is further improved in that, in step S3, the stirring time is 1 hour to 4 hours.

[0019] The above-mentioned method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, and the following treatment is included after the hydrothermal reaction: washing and drying the reaction product; the washing is performed with water 4 to 9 times, the drying temperature is 60°C to 110°C, and the drying time is 8h to 16h.

[0020] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, wherein the degradation treatment is: mixing the iron-doped ZSM5 zeolite with antibiotic wastewater, adding hydrogen peroxide solution, and performing a catalytic degradation reaction.

[0021] The above-mentioned method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, wherein the concentration of hydrogen peroxide in the antibiotic wastewater is 5 mmol / L to 40 mmol / L, the concentration of iron-doped ZSM5 zeolite in the antibiotic wastewater is 0.1 g / L to 0.4 g / L; the initial concentration of antibiotics in the antibiotic wastewater is ≤10 mg / L; and the initial concentration of the hydrogen peroxide solution is 1 mol / L.

[0022] The above method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, wherein the antibiotic in the antibiotic wastewater is at least one of tetracycline hydrochloride, norfloxacin, and sulfamethoxazole.

[0023] The above-mentioned method of using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water is further improved, wherein the mixing process of the iron-doped ZSM5 zeolite and antibiotic wastewater is carried out under stirring conditions, the stirring speed is 250r / min~500r / min, the stirring time is 25min~60min, the catalytic degradation reaction time is 30min~60min, and the catalytic degradation reaction temperature is 288.15K~313.15K.

[0024] Compared with the prior art, the advantages of the present invention are:

[0025] (1) The present invention provides a method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite, wherein the antibiotic pollutants in the water are treated by activating hydrogen peroxide using the iron-doped ZSM5 zeolite as a catalyst, wherein the iron-doped ZSM5 zeolite is prepared by sequentially mixing sodium metaaluminate, tetrapropylammonium hydroxide, water, urea, tetraethoxysilane, and an iron source, and undergoing hydrothermal reaction and calcination, wherein the iron source is at least one of ferrous acetylacetonate, ferric acetylacetonate, or ferric nitrate. In the present invention, sodium metaaluminate, tetrapropylammonium hydroxide, water, urea, tetraethoxysilane, and an iron source are used as raw materials, wherein the iron source is at least one of ferrous acetylacetonate, ferric acetylacetonate, or ferric nitrate. Fe species are first doped into a ZSM5 zeolite framework by a hydrothermal synthesis method, and then during the calcination process, the Fe species are uniformly dispersed and stably fixed in the zeolite framework. On the one hand, the prepared iron-doped ZSM5 zeolite has a composite morphology of nanoparticles and nanosheets, has advantages such as a large specific surface area and a strong adsorption capacity, which is conducive to the rapid adsorption of antibiotics in wastewater by the iron-doped ZSM5 zeolite. On the other hand, the Fe species are uniformly dispersed in the zeolite framework, which can not only increase the number of catalytic active sites, but also increase the contact probability of the active sites with pollutants, thereby exhibiting very excellent catalytic activity, thereby achieving efficient activation of hydrogen peroxide (H2O2) to produce ·OH and superoxide free radicals ·O2 - and singlet oxygen 1O2 and other active oxygen species, and then use these active oxygen species to efficiently degrade antibiotics in water. More importantly, by stably fixing the Fe species in the zeolite framework, the stability of the Fe species can be significantly improved, making it difficult to leach. Not only can it be reused to treat antibiotic wastewater, but it can also achieve a Fe ion leaching amount of 0 mg / L during the entire degradation process, without causing secondary pollution to the environment. Taking tetracycline hydrochloride (TC) as an example, the iron-doped ZSM5 zeolite prepared by the hydrothermal method adopted in the inventive method can completely remove tetracycline hydrochloride from the wastewater within 40 minutes, with a removal rate of 100%. Under the same conditions, the iron-doped ZSM5 zeolite prepared by the conventional impregnation method and ion exchange method has a removal rate of 29.6% and 17.3% higher for tetracycline hydrochloride, respectively. At the same time, in the cycle test, the iron-doped ZSM5 zeolite did not show obvious deactivation and still maintained a high catalytic activity. After five cycle experiments, the removal rate of TC was still 100.0%. In addition, it exhibits significant magnetism before and after use, indicating that it can be easily recovered using a magnetic field, thereby preventing the secondary pollution that may be caused by the long-term presence of the catalyst in the water environment. Furthermore, the method of the present invention expands the applicable pH range for the treatment of antibiotic pollutants in water bodies with iron-doped ZSM5 zeolite. The process has a good oxidative removal effect on antibiotics in water bodies within the initial pH range of 3.0 to 9.0. Even at a pH of 8.99, a nearly 80% removal of tetracycline was achieved within 60 minutes of the experiment, overcoming the drawback of some Fenton reactions that require an acidic pH system. Furthermore, the method of the present invention exhibits good adsorption and oxidative degradation capabilities for different types of antibiotics, demonstrating high practicality. Therefore, in the present invention, the iron-doped ZSM5 zeolite used has the advantages of uniformly dispersed active sites, high catalytic activity, good stability, strong magnetism, and easy recovery. When used to activate hydrogen peroxide, it can generate a large number of active oxygen species, and then these active oxygen species can be used to achieve efficient degradation of antibiotics in wastewater. In particular, during use, Fe species are almost not leached, and it has the advantages of good degradation effect, green and environmental protection, wide pH application range, magnetic recovery, good reusability, convenient operation, low cost, etc., and can achieve efficient degradation of different types of antibiotic wastewater, with high use value and good application prospects.

[0026] (2) The method of the present invention can perform well in degrading antibiotic pollution, is simple and easy to operate, and has the characteristics of low cost, environmental friendliness, and easy catalyst recovery. It is suitable for promotion and can efficiently remove antibiotic pollutants in water bodies. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0028] Figure 1 These are the XRD patterns of the iron-doped ZSM5 zeolites (Fe(II)@ZSM5, Fe(III)@ZSM5) prepared in Examples 1 and 2 of the present invention, the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IM) prepared by the wet impregnation method in Comparative Example 1, and the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IE) prepared by the ion exchange method in Comparative Example 2.

[0029] Figure 2 This is a SEM image of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1 of the present invention.

[0030] Figure 3 This is a TEM image of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1 of the present invention.

[0031] Figure 4 This is a comparison chart of the degradation effects of iron-doped ZSM5 zeolites (Fe(II)@ZSM5, Fe(III)@ZSM5) prepared in Examples 1 and 2 of the present invention, the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IM) prepared by the wet impregnation method in Comparative Example 1, and the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IE) prepared by the ion exchange method in Comparative Example 2 on tetracycline hydrochloride in water.

[0032] Figure 5 Graph showing the degradation effects of different antibiotics on hydrogen peroxide activated by iron-doped ZSM5 zeolite (Fe(II)@ZSM5, Fe-N@ZSM5) in Examples 3 and 4 of the present invention.

[0033] Figure 6 This is a diagram showing the degradation effect of tetracycline hydrochloride on iron-doped ZSM5 zeolite (Fe(II)@ZSM5) activated by hydrogen peroxide under different pH conditions in Example 5 of the present invention.

[0034] Figure 7 This is a diagram showing the degradation effect of tetracycline hydrochloride in water by the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) of Example 7 of the present invention in a recycling experiment.

[0035] Figure 8 This is a hysteresis loop diagram of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) before and after use in Example 7 of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby.

[0037] In the following examples of the present invention, unless otherwise specified, the materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0038] Example 1

[0039] A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite, specifically using iron-doped ZSM5 zeolite and hydrogen peroxide to degrade tetracycline hydrochloride wastewater, comprising the following steps:

[0040] 15 mg of iron-doped ZSM5 zeolite (Fe(II)@ZSM5) was weighed and added to 50 mL of a 10 mg / L, pH 4.4 tetracycline hydrochloride solution. The solution was magnetically stirred at 450 r / min for 30 min to reach adsorption equilibrium. A 1 mol / L hydrogen peroxide solution was added to a hydrogen peroxide concentration of 20 mM. The catalytic degradation reaction was carried out at 298.15 K for 60 min to complete the degradation of tetracycline hydrochloride in the water.

[0041] In this embodiment, the preparation method of iron-doped ZSM5 zeolite (Fe(II)@ZSM5) includes the following steps:

[0042] (1) Add 0.07286 g of sodium aluminate, 13.01 g of tetrapropylammonium hydroxide, and 15.45 g of water into a beaker and stir for 2 h to obtain a mixed solution A.

[0043] (2) 8.32 g of tetraethoxysilane was gradually added to the mixed solution A obtained in step (1) within 30 s, stirred for 6 h, and mixed evenly to obtain a mixed solution B.

[0044] (3) Add 0.5 g of ferrous acetylacetonate to the mixed solution B obtained in step (2), stir for 2 h, and mix evenly to obtain a mixed solution C.

[0045] (4) The mixed solution C obtained in step (3) was subjected to a hydrothermal reaction. The hydrothermal reaction was carried out in a high-pressure reactor at a temperature of 170° C. for 70 h. After completion, the mixture was taken out and cooled. The reaction product was washed 7 times with ultrapure water and then dried in an electric blast drying oven at 105° C. for 10 h.

[0046] (5) The dried product in step (4) was placed in a muffle furnace for calcination at a temperature of 550° C., a heating rate of 2° C. / min, and a calcination time of 6 h to obtain an iron-doped ZSM5 zeolite, which was designated as Fe(II)@ZSM5.

[0047] Example 2:

[0048] A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite is basically the same as the method in Example 1, except that the catalyst used is iron-doped ZSM5 zeolite (Fe(III)@ZSM5) prepared using ferric acetylacetonate as the iron source.

[0049] In this embodiment, the preparation method of iron-doped ZSM5 zeolite (Fe(III)@ZSM5) includes the following steps:

[0050] (1) Add 0.07286 g of sodium aluminate, 13.01 g of tetrapropylammonium hydroxide, and 15.45 g of water into a beaker and stir for 2 h to obtain a mixed solution A.

[0051] (2) 8.32 g of tetraethoxysilane was gradually added to the mixed solution A obtained in step (1) within 30 s, stirred for 6 h, and mixed evenly to obtain a mixed solution B.

[0052] (3) Add 0.5 g of ferric acetylacetonate to the mixed solution B obtained in step (2), stir for 2 h, and mix evenly to obtain a mixed solution C.

[0053] (4) The mixed solution C obtained in step (3) was subjected to a hydrothermal reaction. The hydrothermal reaction was carried out in a high-pressure reactor at a temperature of 170° C. for 70 h. After completion, the mixture was taken out and cooled. The reaction product was washed 7 times with ultrapure water and then dried in an electric blast drying oven at 105° C. for 10 h.

[0054] (5) The dried product in step (4) was placed in a muffle furnace for calcination at a temperature of 550° C., a heating rate of 2° C. / min, and a calcination time of 6 h to obtain an iron-doped ZSM5 zeolite, which was designated as Fe(III)@ZSM5.

[0055] Comparative Example 1:

[0056] A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite is basically the same as the method in Example 1, except that the catalyst used is iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IM) prepared by a wet impregnation method.

[0057] In this embodiment, the method for preparing iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IM) by wet impregnation method includes the following steps:

[0058] (1) First, 0.07 g of ferric acetylacetonate and 2 g of ZSM5 zeolite (commercially available) were suspended in 120 mL of ultrapure water and mechanically stirred at 40° C. until the water evaporated to obtain a solid.

[0059] (2) The solid obtained in step (1) was dried in an electric blast drying oven at 105° C. for 10 h.

[0060] (3) The dried product in step (2) was placed in a muffle furnace for calcination at a temperature of 550°C, a heating rate of 2°C / min, and a calcination time of 6 hours to obtain an iron-doped ZSM5 zeolite prepared by a wet impregnation method, which was recorded as Fe(III) / ZSM5-IM.

[0061] Comparative Example 2:

[0062] A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite is basically the same as the method in Example 1, except that the catalyst used is iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IE) prepared by ion exchange.

[0063] In this embodiment, the preparation method of iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IE) prepared by ion exchange method includes the following steps:

[0064] (1) First, 0.07 g of iron acetylacetonate and 2 g of ZSM5 zeolite (commercially available) were suspended in 120 mL of ultrapure water and mechanically stirred at room temperature for 1 day.

[0065] (2) The solid obtained in step (1) was centrifugally washed with ultrapure water for more than 2 times to remove excess iron species that did not participate in ion exchange, and then dried in an electric blast drying oven at 105° C. for 10 h.

[0066] (3) The dried product in step (2) was placed in a muffle furnace for calcination at a temperature of 550°C, a heating rate of 2°C / min, and a calcination time of 6 hours to obtain an iron-doped ZSM5 zeolite prepared by an ion exchange method, which was recorded as Fe(III) / ZSM5-IE.

[0067] Figure 1The XRD patterns of the iron-doped ZSM5 zeolites (Fe(II)@ZSM5, Fe(III)@ZSM5) prepared in Examples 1 and 2 of the present invention, the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IM) prepared by the wet impregnation method in Comparative Example 1, and the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IE) prepared by the ion exchange method in Comparative Example 2 are shown. Figure 1 It can be seen that the four zeolite-based catalysts, Fe(II)@ZSM5, Fe(III)@ZSM5, Fe(III) / ZSM5-IM and Fe(III) / ZSM5-IE, all conform to the characteristic peaks of typical ZSM5 zeolite after comparison with the PDF standard card of ZSM5 zeolite, which is consistent with the crystal structure of zeolite.

[0068] Figure 2 This is a SEM image of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1 of the present invention. Figure 2 In the figure, (a) is a 100nm scale and (b) is a 200nm scale. Figure 2 It can be seen that Fe(II)@ZSM5 presents a uniform composite structure of nanoparticles and nanosheets with a large specific surface area, indicating that it has good adsorption capacity. At the same time, there are no obvious iron oxide particles, indicating that the Fe species are uniformly dispersed and the catalyst has good catalytic activity.

[0069] Figure 3 This is a TEM image of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1 of the present invention. Figure 3 In the figure, (a) is a 20nm scale and (b) is a 200nm scale. Figure 3 It can be seen that under the condition that the scale bar in (a) is 20nm, there are obvious lattice fringes, and the lattice spacing is 0.98nm, which is basically consistent with the (0 20) crystal plane in the standard card PDF#44-0003 of ZSM5, which once again confirms that it maintains the crystal structure of ZSM5. Figure 3 It can be seen that the uniform distribution of Fe element is directly confirmed under the scale of 200 nm in (b) and the corresponding X-ray energy spectrum element analysis technology image (EDS mapping).

[0070] During the magnetic stirring and degradation process of Example 1-2 and Comparative Example 1-2, 1 mL of sample was taken every 10 min, and the sample was filtered with a 0.22 μm filter head. The filtrate was measured by liquid chromatography to determine the concentration of pollutants after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of different types of iron-doped ZSM5 zeolites on antibiotics. The results are shown in FIG. Figure 4 shown.

[0071] Figure 4The figure shows the comparison of the degradation effects of the iron-doped ZSM5 zeolites (Fe(II)@ZSM5, Fe(III)@ZSM5) prepared in Examples 1 and 2 of the present invention, the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IM) prepared by the wet impregnation method in Comparative Example 1, and the iron-doped ZSM5 zeolite (Fe(III) / ZSM5-IE) prepared by the ion exchange method in Comparative Example 2 on tetracycline hydrochloride in water. Figure 4 It can be seen that after 30 minutes of adsorption and 40 minutes of oxidative degradation, the removal rates of tetracycline hydrochloride by Fe(II)@ZSM5, Fe(III)@ZSM5, Fe(III) / ZSM5-IM, and Fe(III) / ZSM5-IE through activation of hydrogen peroxide H2O2 were 100%, 99.9%, 70.4%, and 82.7%, respectively. This is because the Fe(II)@ZSM5 prepared with ferrous acetylacetonate as the iron source has higher catalytic activity and is more likely to undergo Fenton reaction with H2O2. At the same time, it can be seen that the catalytic performance of the iron-doped ZSM5 zeolite prepared by the hydrothermal synthesis method is significantly better than that of the zeolite-based catalyst prepared by the wet impregnation method or ion exchange method. This indicates that due to the excellent stability of the organic iron precursor under alkaline conditions, the Fe species may be doped into the zeolite framework in the form of a complex during the hydrothermal synthesis process, thereby obtaining a more uniform morphology and higher activity, which is conducive to the activation of hydrogen peroxide to produce ·OH, ·O2 - and 1 O2 and other reactive oxygen species, thereby efficiently degrading antibiotics.

[0072] Example 3:

[0073] A method for degrading antibiotics in water using iron-doped ZSM5 zeolite activated hydrogen peroxide, specifically using iron-doped ZSM5 zeolite activated hydrogen peroxide to degrade tetracycline hydrochloride, sulfamethoxazole, and norfloxacin wastewater, respectively, comprising the following steps:

[0074] Weigh 3 parts of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1, 15 mg each, and add them to a tetracycline hydrochloride (TC) solution, a sulfamethoxazole (SMX) solution, and a norfloxacin (NOR) solution, respectively. The volume of each solution is 50 mL and the concentration is 10 mg / L. The mixture is magnetically stirred at a speed of 450 r / min for 30 min to reach adsorption equilibrium. A hydrogen peroxide solution with a concentration of 1 mol / L is added to make the hydrogen peroxide concentration in the system 20 mM. The degradation reaction is carried out at a temperature of 298.15 K for 60 min to complete the degradation of various antibiotics in the water.

[0075] During the magnetic stirring and degradation process, 1 mL of sample was taken every 10 minutes and filtered with a 0.22 μm filter head. The filtrate was measured by liquid chromatography to determine the pollutant concentrations after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of the iron-doped ZSM5 zeolite of the present invention on various antibiotics.

[0076] Example 4:

[0077] A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite, specifically using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade tetracycline hydrochloride, sulfamethoxazole, and norfloxacin wastewater, respectively. The method is basically the same as the method in Example 3, except that the catalyst used is iron-doped ZSM5 zeolite (Fe-N@ZSM5) prepared by using ferric nitrate nonahydrate as the iron source.

[0078] In this embodiment, the preparation method of iron-doped ZSM5 zeolite (Fe-N@ZSM5) includes the following steps:

[0079] (1) Add 0.07286 g of sodium aluminate, 13.01 g of tetrapropylammonium hydroxide, and 15.45 g of water into a beaker and stir for 2 h to obtain a mixed solution A.

[0080] (2) 8.32 g of tetraethoxysilane was gradually added to the mixed solution A obtained in step (1) within 30 s, stirred for 6 h, and mixed evenly to obtain a mixed solution B.

[0081] (3) Add 0.5 g of ferric nitrate nonahydrate to the mixed solution B obtained in step (2), stir for 2 h, and mix evenly to obtain a mixed solution C;

[0082] (4) The mixed solution C obtained in step (3) was subjected to a hydrothermal reaction. The hydrothermal reaction was carried out in a high-pressure reactor at a temperature of 170° C. for 70 h. After completion, the mixture was taken out and cooled. The reaction product was washed 7 times with ultrapure water and then dried in an electric blast drying oven at 105° C. for 10 h.

[0083] (5) The dried product in step (4) was placed in a muffle furnace for calcination at a temperature of 550° C., a heating rate of 2° C. / min, and a calcination time of 6 h to obtain an iron-doped ZSM5 zeolite, which was designated as Fe-N@ZSM5.

[0084] During the magnetic stirring and degradation process, 1 mL of sample was taken every 10 minutes and filtered with a 0.22 μm filter head. The filtrate was measured by liquid chromatography to determine the pollutant concentrations after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of the iron-doped ZSM5 zeolite of the present invention on various antibiotics.

[0085] Figure 5 The figure shows the degradation effect of different antibiotics by hydrogen peroxide activated by iron-doped ZSM5 zeolite (Fe(II)@ZSM5, Fe-N@ZSM5) in Examples 3 and 4 of the present invention. Figure 5 It can be seen that after 60 minutes of degradation reaction, the removal rates of Fe(II)@ZSM5 for tetracycline hydrochloride (TC) solution, sulfamethoxazole (SMX) solution, and norfloxacin (NOR) solution reached 100%, 89.5%, and 100%, respectively. The removal rates of Fe-N@ZSM5 for tetracycline hydrochloride (TC) solution, sulfamethoxazole (SMX) solution, and norfloxacin (NOR) solution all reached 100%. It can be seen that the iron-doped ZSM5 zeolites (Fe(II)@ZSM5 and Fe-N@ZSM5) prepared by the present invention using ferric acetylacetonate and ferric nitrate nonahydrate as the iron source exhibit excellent degradation effects against various antibiotics by hydrogen peroxide activation.

[0086] Example 5:

[0087] A method for degrading antibiotics in water using iron-doped ZSM5 zeolite activated hydrogen peroxide, specifically using iron-doped ZSM5 zeolite activated hydrogen peroxide to degrade tetracycline hydrochloride wastewater with different pH values, comprising the following steps:

[0088] Weigh 4 parts of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1, 15 mg each, and add them to tetracycline hydrochloride solutions with pH values ​​of 3.02, 4.99, 7.07, and 8.99, respectively. The volume of each solution is 50 mL, the concentration is 10 mg / L, and magnetic stirring is carried out at a speed of 450 r / min for 30 min to reach adsorption equilibrium. Then, a hydrogen peroxide solution with a concentration of 1 mol / L is added to make the hydrogen peroxide concentration in the system 20 mM. The degradation reaction is carried out at a temperature of 298.15 K for 60 min to complete the degradation of tetracycline hydrochloride in the water.

[0089] During the magnetic stirring and degradation process, 1 mL of sample was taken every 10 minutes and filtered with a 0.22 μm filter head. The filtrate was measured by liquid chromatography to determine the pollutant concentration after adsorption and degradation, thereby obtaining the adsorption effect and catalytic degradation effect of iron-doped ZSM5 zeolite on tetracycline hydrochloride under different pH conditions.

[0090] Figure 6 The figure shows the degradation effect of tetracycline hydrochloride on the activation of hydrogen peroxide by iron-doped ZSM5 zeolite (Fe(II)@ZSM5) under different pH conditions in Example 5 of the present invention. Figure 6It can be seen that the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) of the present invention has a 100% removal rate for tetracycline hydrochloride under acidic and neutral pH conditions, and also achieves a removal effect of over 80% under alkaline pH conditions, indicating that the method of the present invention has a wide pH applicability range and can overcome the disadvantage that some Fenton reactions require an acidic pH for the system.

[0091] Example 6:

[0092] The Fe leaching of iron-doped ZSM5 zeolite during the degradation of TC and SMX was investigated.

[0093] The iron-doped ZSM5 zeolites (Fe(II)@ZSM5 and Fe-N@ZSM5) prepared in Examples 1 and 4, respectively, were used to activate hydrogen peroxide to degrade TC and SMX in water. The process was essentially the same as in Example 1, except that the TC and SMX solutions were subjected to magnetic stirring and degradation. After a total reaction time of 90 minutes, a 2 mL sample was taken and filtered through a 0.22 μm filter. Then, 1 mL of the filtrate was taken into a 10 mL centrifuge tube, and 4 mL of ultrapure water was added. After mixing, the concentration of Fe ions leached during the reaction was determined by inductively coupled plasma mass spectrometry. The results are shown in Table 1.

[0094] Table 1 Comparison of Fe leaching concentrations of iron-doped ZSM5 zeolites (Fe(II)@ZSM5, Fe-N@ZSM5) prepared in Example 1 and Example 4 during activation of hydrogen peroxide to degrade antibiotic wastewater

[0095] Catalyst type Types of antibiotics Reaction time (min) Fe ion leaching concentration (mg / L) Fe(II)@ZSM5 Tetracycline hydrochloride (TC) 90 0 Fe(II)@ZSM5 Sulfamethoxazole (SMX) 90 0 Fe-N@ZSM5 Tetracycline hydrochloride (TC) 90 0 Fe-N@ZSM5 Sulfamethoxazole (SMX) 90 0

[0096] As shown in Table 1, the iron-doped ZSM5 zeolites (Fe(II)@ZSM5 and Fe-N@ZSM5) of the present invention leached 0 mg / L of Fe during the degradation of antibiotics with activated hydrogen peroxide. This indicates that the preparation method of the present invention enables the Fe species to be very stably doped into the zeolite framework, resulting in almost no Fe leaching during the degradation process, thereby effectively avoiding secondary contamination.

[0097] Example 7:

[0098] The repeated degradation effect of the iron-doped ZSM5 zeolite was investigated. Specifically, the iron-doped ZSM5 zeolite prepared in Example 1 was used to activate hydrogen peroxide to degrade tetracycline hydrochloride wastewater, and the catalyst was recovered and used to degrade new tetracycline hydrochloride wastewater, comprising the following steps:

[0099] (1) 15 mg of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) prepared in Example 1 was weighed and added to a 50 mL tetracycline hydrochloride solution having a concentration of 10 mg / L and a pH of 4.4. The solution was magnetically stirred at a speed of 450 r / min for 30 min to reach adsorption equilibrium. A hydrogen peroxide solution having a concentration of 1 mol / L was added to make the hydrogen peroxide concentration in the system 20 mM. The degradation reaction was carried out at a temperature of 298.15 K for 60 min to complete the degradation of tetracycline hydrochloride in the water.

[0100] (2) After degradation, the catalyst was washed with water three times, washed with ethanol three times, and dried in an electric blast drying oven at 105°C for 10 h to complete the catalyst recovery operation.

[0101] (3) Repeat the operations in steps (1) and (2) to adsorb and degrade the new tetracycline hydrochloride solution for a total of 5 times.

[0102] During the magnetic stirring and degradation process, 1 mL of sample was taken every 10 minutes and filtered through a 0.22 μm filter head. The filtrate was measured by liquid chromatography to determine the pollutant concentrations after adsorption and after degradation, thereby obtaining the adsorption effect and catalytic degradation effect of the iron-doped ZSM5 zeolite of the present invention on tetracycline hydrochloride in water in a recycling recovery experiment.

[0103] Figure 7 This is a graph showing the degradation effect of tetracycline hydrochloride in water by iron-doped ZSM5 zeolite (Fe(II)@ZSM5) in a recycling experiment in Example 7 of the present invention. Figure 7 It can be seen that in the 5-cycle experiment, the catalytic activity of Fe(II)@ZSM5 did not decrease significantly, and the removal rate of tetracycline hydrochloride still reached 100%, showing good stability.

[0104] Figure 8 : This is the hysteresis loop diagram of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) before and after use in Example 7 of the present invention. Figure 8 It can be seen that the hysteresis loops of the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) before use and the iron-doped ZSM5 zeolite (Fe(II)@ZSM5) recovered after five cycles both exhibit ferromagnetism / ferrimagnetism, with saturation magnetization intensities of 0.653emu / g and 0.632emu / g, respectively, confirming that the materials are strong magnetic materials and can be effortlessly recovered through a magnetic field after use, thereby preventing secondary pollution that may be caused by the long-term presence of the catalyst in the water environment.

[0105] From the above results, it can be seen that the iron-doped ZSM5 zeolite used in the present invention has the advantages of uniformly dispersed active sites, high catalytic activity, good stability, strong magnetism and easy recovery. When used to activate hydrogen peroxide, it can generate a large number of reactive oxygen species, and then these reactive oxygen species can be used to achieve efficient degradation of antibiotics in wastewater. In particular, Fe species are almost not leached during use. Therefore, the method of the present invention using iron-doped ZSM5 zeolite to activate hydrogen peroxide to degrade antibiotics in water can achieve efficient degradation of different types of antibiotic wastewater, and has the advantages of good degradation effect, green environmental protection, wide pH application range, magnetic recovery, good reusability, easy operation, low cost, etc. It is a new method suitable for promotion and application and can efficiently and thoroughly remove antibiotic pollution in water, with high use value and good application prospects.

[0106] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of protection of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that can be made by a person skilled in the art without departing from the principles of the present invention are also considered to be within the scope of protection of the present invention.

Claims

1. A method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite, characterized in that: Antibiotic wastewater is degraded by using iron-doped ZSM5 zeolite as a catalyst to activate hydrogen peroxide; the iron-doped ZSM5 zeolite is prepared by sequentially mixing sodium metaaluminate, tetrapropylammonium hydroxide, water, tetraethoxysilane, and an iron source, undergoing a hydrothermal reaction, and calcining; the iron source is at least one of ferrous acetylacetonate, ferric acetylacetonate, or ferric nitrate.

2. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 1, characterized in that: The preparation steps of the iron-doped ZSM5 zeolite include: S1. Mix sodium metaaluminate, tetrapropylammonium hydroxide and water, and stir to obtain a mixed solution A; S2, adding tetraethoxysilane to the mixed solution A, stirring to obtain a mixed solution B; S3, adding an iron source to the mixed solution B and stirring to obtain a mixed solution C; S4, performing a hydrothermal reaction on the mixed solution C to obtain a hydrothermal reaction product; S5. calcining the hydrothermal reaction product to obtain iron-doped ZSM5 zeolite.

3. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 2, characterized in that: The mass ratio of the tetraethoxysilane, sodium aluminate, tetrapropylammonium hydroxide, iron source and water is 8.32:0.07286:13.01:0.5:15.

45.

4. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 2, characterized in that: In step S4, the reaction temperature of the hydrothermal reaction is 140° C. to 190° C., and the reaction time of the hydrothermal reaction is 60 h to 108 h; In step S5, the calcination temperature is 500° C. to 650° C., the calcination temperature rise rate is 1° C. / min to 6° C. / min, and the calcination time is 2 h to 7 h.

5. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 2, characterized in that: In step S1, the stirring time is 1 h to 4 h; In step S2, the stirring time is 4h to 7h; In step S3, the stirring time is 1 h to 4 h.

6. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 2, characterized in that: The hydrothermal reaction is followed by the following treatments: washing and drying the reaction product; the washing is performed with water 4 to 9 times, the drying temperature is 60° C. to 110° C., and the drying time is 8 to 16 hours.

7. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to any one of claims 1 to 6, characterized in that: The degradation treatment comprises: mixing iron-doped ZSM5 zeolite with antibiotic wastewater, adding hydrogen peroxide solution, and performing a catalytic degradation reaction.

8. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 7, characterized in that: The concentration of hydrogen peroxide in the antibiotic wastewater is 5 mmol / L to 40 mmol / L, the concentration of iron-doped ZSM5 zeolite in the antibiotic wastewater is 0.1 g / L to 0.4 g / L; the initial concentration of antibiotics in the antibiotic wastewater is ≤10 mg / L; and the initial concentration of the hydrogen peroxide solution is 1 mol / L.

9. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 8, characterized in that: The antibiotic in the antibiotic wastewater is at least one of tetracycline hydrochloride, norfloxacin, and sulfamethoxazole.

10. The method for degrading antibiotics in water by activating hydrogen peroxide using iron-doped ZSM5 zeolite according to claim 9, characterized in that: The mixing process of the iron-doped ZSM5 zeolite and antibiotic wastewater is carried out under stirring conditions, the stirring speed is 250r / min to 500r / min, the stirring time is 25min to 60min, the catalytic degradation reaction time is 30min to 60min, and the catalytic degradation reaction temperature is 288.15K to 313.15K.

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