A method for degrading tetracycline antibiotics in water

Abstract

The application provides a degradation method of tetracycline antibiotics in water. The degradation method comprises the following steps: preparing AgCl / MIL-100 (Fe) MOF material, mixing the MOF material, TiO2 and ZnO with water containing tetracycline antibiotics in dark conditions, controlling the mass ratio of the MOF material, TiO2 and ZnO to be 1: (0.1-0.5): (1.2-2.5), and then starting a light source to carry out photocatalysis reaction to degrade the tetracycline antibiotics in the water. In the degradation method, the MOF material with excellent performance is obtained through a specific method, and the MOF material is mixed with TiO2 and ZnO, so that the degradation rate of the tetracycline antibiotics in the water can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water pollution treatment, in particular to a method for degrading tetracycline antibiotics in water. BACKGROUND

[0002] With the rapid development of medicine and animal husbandry, tetracycline antibiotics are widely used in clinical treatment and livestock breeding due to their broad-spectrum antibacterial properties. However, as they are difficult to be completely metabolized by organisms, a large amount of unused tetracycline antibiotics are discharged into water environment with wastewater. Tetracycline antibiotics in water not only disrupt the balance of aquatic ecosystems and affect the growth and reproduction of aquatic organisms, but also may be transmitted through the food chain, posing a potential threat to human health. In addition, tetracycline antibiotics persisting in water for a long time can induce bacterial resistance, further exacerbating public health problems.

[0003] Currently, the main methods for treating tetracycline antibiotics in water include physical methods, chemical methods and biological methods. Physical methods such as adsorption method, although simple to operate, only transfer antibiotics from water to adsorbents, do not fundamentally eliminate pollution, and adsorbents have saturation problems, making subsequent treatment difficult. Although advanced oxidation technology in chemical methods can effectively degrade antibiotics, it often requires the use of a large amount of chemical reagents, which is costly and may cause secondary pollution. Biological methods have relatively low treatment efficiency, long treatment period, and strict requirements for environmental conditions, making it difficult to deal with high-concentration, complex-component antibiotic-polluted water bodies. Therefore, it is of great practical significance to develop an efficient, environmentally friendly and economical method for degrading tetracycline antibiotics in water. SUMMARY

[0004] Based on the above problems, the present application provides a method for degrading tetracycline antibiotics in water, which prepares a specific AgCl / MIL-100(Fe) MOF material, and reasonably matches it with TiO2 and ZnO to build an efficient composite photocatalytic system, realizing rapid and efficient degradation of tetracycline antibiotics in water, overcoming the deficiencies in the prior art.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A method for degrading tetracycline antibiotics in water, comprising the following steps:

[0007] S101: preparing AgCl / MIL-100(Fe) MOF material:

[0008] Dissolve the iron ion source and trimesic acid in water, and adjust the pH value to 4.5-5.5 to obtain a reaction solution;

[0009] The reaction solution is stirred at 20-30℃ for 20-30h, and then washed and dried to obtain MIL-100(Fe);

[0010] The MIL-100(Fe) is mixed with a silver ion solution, stirred for 2-5h, and then a chloride ion solution is added dropwise and stirred for 5-10h under natural light irradiation, and then washed and dried to obtain an AgCl / MIL-100(Fe) MOF material;

[0011] S102: photocatalytic degradation:

[0012] The AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO are mixed with a water body containing tetracycline antibiotics under dark conditions, and the mass ratio of the AgCl / MIL-100(Fe) MOF material, the TiO2 and the ZnO is controlled to be 1:(0.1-0.5):(1.2-2.5), and the mixed system is stirred in the dark for 0.5-1h, and then a light source is turned on for photocatalytic reaction, the light source is a visible light source, and the light intensity of the light source is 50-200mW / cm².

[0013] Optionally, the reaction temperature of the photocatalytic reaction is 20-30℃, and the reaction time is 1-3h.

[0014] Optionally, the visible light source is a tungsten lamp light source with a 400nm cut-off filter.

[0015] Optionally, the mass ratio of the AgCl / MIL-100(Fe) MOF material, the TiO2 and the ZnO is 1:0.3:2.

[0016] Optionally, the molar ratio of iron ions in the iron ion source to the trimesic acid is (1.1-1.5):1.

[0017] Optionally, the iron ion source includes at least one of FeCl3 4H2O and Fe(NO3)3 9H2O.

[0018] Optionally, the molar concentration of silver ions in the silver ion solution is 50-60mmol / L.

[0019] Optionally, the molar concentration of chloride ions in the chloride ion solution is 10-15mmol / L.

[0020] Optionally, the volume ratio of the silver ion solution to the chloride ion solution is 1:(3-5).

[0021] Optionally, the mass ratio of the MIL-100(Fe) to the silver ions in the silver ion solution is (1.1-1.3):1.

[0022] Advantages

[0023] The AgCl / MIL-100(Fe) MOF material obtained by the specific preparation method has a high specific surface area and abundant active sites, and can effectively adsorb tetracycline antibiotics. Meanwhile, the composite photocatalytic system constructed by mixing the AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO according to a specific mass ratio can significantly improve the separation efficiency of photo-generated carriers and broaden the light response range, so as to realize efficient degradation of tetracycline antibiotics in water. In some embodiments, the degradation rate of tetracycline antibiotics in the degradation method of the present application can reach 95% or more.

[0024] In addition, the degradation method of the present application mainly utilizes photocatalytic reaction, does not need to use a large amount of chemical reagents, has mild reaction conditions, and will not produce secondary pollution. At the same time, the raw materials used in the degradation method have low cost, and have good economic benefits and environmental benefits.

[0025] Further, the entire degradation process of the present application is simple to operate, has low requirements for reaction equipment, and is easy to realize industrial application. By controlling the parameters such as the ratio of materials and reaction conditions, the degradation efficiency can be flexibly adjusted to meet the treatment needs of tetracycline antibiotic pollution in different water bodies. DETAILED DESCRIPTION

[0026] One embodiment of the present application provides a degradation method of tetracycline antibiotics in water. The degradation method of tetracycline antibiotics in water comprises the following steps:

[0027] S101: preparing an AgCl / MIL-100(Fe) MOF material: dissolving an iron ion source and trimesic acid in water, and adjusting the pH value to 4.5-5.5 to obtain a reaction solution. After stirring the reaction solution at 20-30℃ for 20-30h, washing and drying, MIL-100(Fe) is obtained. The MIL-100(Fe) is mixed with a silver ion solution, stirred for 2-5h, then a chloride ion solution is added dropwise, and stirred for 5-10h under natural light irradiation, washed and dried to obtain the AgCl / MIL-100(Fe) MOF material.

[0028] S102: photocatalytic degradation: the AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO are mixed with the water body containing tetracycline antibiotics in the dark condition, the mass ratio of the AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO is controlled to be 1:(0.1-0.5):(1.2-2.5), the mixed system is stirred in the dark for 0.5h-1h, and then the light source is turned on to carry out photocatalytic reaction, the light source is a visible light source, and the light intensity of the light source is 50mW / cm2-200mW / cm2.

[0029] In the above degradation method, the AgCl / MIL-100(Fe) MOF material obtained by the specific preparation method has a high specific surface area and rich active sites, and can effectively adsorb tetracycline antibiotics. Meanwhile, the composite photocatalytic system constructed by mixing the AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO according to a specific mass ratio can significantly improve the separation efficiency of photo-generated carriers and broaden the light response range, so as to realize efficient degradation of tetracycline antibiotics in water.

[0030] In addition, the degradation method of the present application mainly utilizes photocatalytic reaction, does not need to use a large amount of chemical reagents, has mild reaction conditions, and will not produce secondary pollution. At the same time, the raw materials used in the degradation method have low cost, good economic benefit and environmental benefit.

[0031] Further, the entire degradation process of the present application is simple in operation, has low requirements for reaction equipment, and is easy to realize industrial application. By controlling the material ratio, reaction conditions and other parameters, the degradation efficiency can be flexibly adjusted to meet the treatment needs of tetracycline antibiotic pollution in different water bodies.

[0032] Alternatively, the molar ratio of iron ions in the iron ion source to the trimesic acid is (1.1-1.5):1. The molar ratio of iron ions in the iron ion source to the trimesic acid in this range can make the crystal structure of MIL-100(Fe) have fewer defects, and can make MIL-100(Fe) have larger porosity.

[0033] Alternatively, in S101, the stirring speed during the stirring reaction of the reaction solution at 20-30℃ for 20-30h can be 300-500rpm. For example, the stirring speed can be 300rpm, 350rpm, 400rpm, 450rpm, 500rpm, etc. It can be understood that the stirring speed can also be other appropriate choices within the range of 300-500rpm.

[0034] Optionally, in S101, the reaction liquid can be stirred at 20-30℃ for 20-30h. The reaction temperature can be 20℃, 22℃, 25℃, 28℃, 30℃, etc. It can be understood that the reaction temperature can also be selected as other appropriate values within the range of 20-30℃. The reaction time can be 20h, 22h, 25h, 28h, 30h, etc. It can be understood that the reaction time can also be selected as other appropriate values within the range of 20-30h.

[0035] It can be understood that after the reaction liquid is stirred at 20-30℃ for 20-30h, MIL-100(Fe) can be obtained by filtration, washing, and drying. The washing can be water washing.

[0036] Optionally, during the mixing of MIL-100(Fe) and the silver ion solution and stirring for 2-5h, the stirring speed can be high, for example, the stirring speed can be 1000-1500rpm. Further optionally, the stirring speed of the mixing of MIL-100(Fe) and the silver ion solution can be 1000rpm, 1100rpm, 1200rpm, 1300rpm, 1400rpm, 1500rpm, etc. The stirring time can be 2h, 3h, 4h, 5h, etc.

[0037] Optionally, after the mixing reaction of MIL-100(Fe) and the silver ion solution, the chloride ion solution is added dropwise, and during the stirring under natural light irradiation for 5-10h, the stirring speed can be 200-300rpm. For example, the stirring speed can be 200rpm, 220rpm, 250rpm, 280rpm, 300rpm, etc. The stirring time can be 5h, 6h, 7h, 8h, 9h, 10h, etc.

[0038] It can be understood that after the mixing of MIL-100(Fe) and the silver ion solution, stirring for 2-5h, and then adding the chloride ion solution dropwise and stirring under natural light irradiation for 5-10h, AgCl / MIL-100(Fe) MOF material can be obtained by filtration, washing, and drying. The washing can be water washing.

[0039] In S102 of the above embodiment, when the proportion of TiO2 is less than 0.1, its ability to capture and transfer photo-generated electrons is limited, and the photocatalytic efficiency of the composite system is not obviously improved; as the proportion of TiO2 increases to 0.5, the separation efficiency of photo-generated carriers is significantly improved, but too much TiO2 can block the absorption of light by AgCl / MIL-100(Fe) MOF material. Therefore, the mass ratio of AgCl / MIL-100(Fe) MOF material to TiO2 is 1:(0.1-0.5).

[0040] When the mass ratio of the AgCl / MIL-100(Fe) MOF material to ZnO is 1:(1.2-2.5), the AgCl / MIL-100(Fe) MOF material and TiO2 can form a good energy band matching, and the light response range is widened from the ultraviolet light region to the visible light region.

[0041] Optionally, the mass ratio of the AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO is 1:0.3:2.

[0042] The mixed system is stirred in the dark for 0.5-1 h to make the material fully contact and adsorb the water body. After 1 h of dark adsorption, the adsorption amount of the tetracycline antibiotic on the material surface can reach 70%-80% of the equilibrium adsorption amount. Then, the light source is turned on for photocatalytic reaction. The light source is a visible light source, and the light intensity is 50-200 mW / cm2. At a lower light intensity (such as 50 mW / cm2), the amount of photo-generated carriers is limited, and the degradation rate is slow. When the light intensity increases to 200 mW / cm2, the recombination probability of photo-generated carriers also increases.

[0043] Optionally, the stirring speed in the dark is 150-250 rpm. For example, the stirring speed in the dark can be 150 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm, etc.

[0044] Optionally, the reaction temperature of the photocatalytic reaction is 20-30℃, and the reaction time is 1-3 h. The reaction temperature is controlled at 20-30℃. The effect of temperature on the photocatalytic reaction mainly reflects on the reaction rate and the stability of the material. At 20℃, the reaction rate is relatively slow, but the stability of the material is good. As the temperature increases to 30℃, the reaction rate increases, but too high temperature may cause changes in the structure of the material, affecting its reuse performance. The reaction time is 1-3 h. Under the preferred conditions, the degradation rate of the tetracycline antibiotic can be more than 95%.

[0045] Optionally, the visible light source is a tungsten lamp light source with a 400 nm cut-off filter.

[0046] Optionally, the molar concentration of silver ions in the silver ion solution is 50-60 mmol / L. For example, the molar concentration of silver ions in the silver ion solution can be 50 mmol / L, 52 mmol / L, 55 mmol / L, 58 mmol / L, 60 mmol / L, etc. Optionally, the silver ion solution is a silver nitrate solution.

[0047] Optionally, the molar concentration of the chloride ions in the chloride ion solution is 10-15 mmol / L. For example, the molar concentration of the chloride ions in the chloride ion solution can be 10 mmol / L, 12 mmol / L, 15 mmol / L, etc. Optionally, the chloride ion solution is a sodium chloride solution.

[0048] Optionally, the volume ratio of the silver ion solution to the chloride ion solution is 1: (3-5). For example, the volume ratio of the silver ion solution to the chloride ion solution can be 1:3, 1:4, 1:5, etc.

[0049] Optionally, the mass ratio of MIL-100 (Fe) to silver ions in the silver ion solution is (1.1-1.3):1.

[0050] Example 1

[0051] The method for degrading tetracycline antibiotics in the water body in this embodiment is as follows:

[0052] S101: Preparation of AgCl / MIL-100 (Fe) MOF material: 2.26 g of FeCl3 4H2O and 1.676 g of trimesic acid were dissolved in 120 mL of deionized water, and the pH value was adjusted to 5 by using a 1 mol / L sodium hydroxide solution, and stirred at 25°C for 24 h, washed and dried to obtain MIL-100 (Fe). 0.2 g of MIL-100 (Fe) was added to 28 mL of silver nitrate solution (the molar concentration of silver nitrate was 53.7 mmol / L), and stirred at a speed of 1500 rpm for 3 h. Then, 98 mL of NaCl solution (the molar concentration of sodium chloride solution was 10.48 mmol / L) was added dropwise (the addition rate was about 10 mL / min), and fully stirred under natural light irradiation for 8 h. After repeated washing and overnight drying, the AgCl / MIL-100 (Fe) MOF material was obtained.

[0053] S102: Photocatalytic degradation: AgCl / MIL-100 (Fe) MOF material, TiO2 and ZnO were mixed with the water body containing tetracycline antibiotics under dark conditions, and the mass ratio of AgCl / MIL-100 (Fe) MOF material, TiO2 and ZnO was controlled to be 1:0.3:2. The mixed system was stirred in the dark for 0.8 h, and then the light source was turned on for photocatalytic reaction. A tungsten lamp light source with a 400 nm cutoff filter was used as a visible light source, and the light intensity of the light source was 100 mW / cm². After the reaction, the concentration of tetracycline antibiotics in the water body was determined by high performance liquid chromatography, and the degradation rate was calculated to be 96%.

[0054] Example 2

[0055] Compared with Example 1, the difference of Example 2 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0.1:1.2.

[0056] After the reaction, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 88%.

[0057] Example 3

[0058] Compared with Example 1, the difference of Example 3 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0.5:2.5.

[0059] After the reaction, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 87%.

[0060] Example 4

[0061] Compared with Example 1, the difference of Example 4 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0.1:2.5.

[0062] After the reaction, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 91%.

[0063] Example 5

[0064] Compared with Example 1, the difference of Example 5 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0.5:1.2.

[0065] After the reaction, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 92%.

[0066] Comparative Example 1

[0067] The degradation method of tetracycline antibiotics in the water body in this comparative example comprises:

[0068] S101: Preparation of MIL-100(Fe) MOF material: 2.26g FeCl3 4H2O and 1.676g of trimesic acid are dissolved in 120mL of deionized water, and the pH value is adjusted to 5 by using 1mol / L sodium hydroxide solution, stirred at 25℃ for 24h, washed and dried to obtain MIL-100(Fe) MOF material.

[0069] S102: photocatalytic degradation: the MIL-100(Fe) MOF material, TiO2 and ZnO are mixed with the water body containing tetracycline antibiotics under dark conditions, the mass ratio of the MIL-100(Fe) MOF material, TiO2 and ZnO is controlled to be 1:0.3:2, the mixed system is stirred in the dark for 0.8h, then the light source is turned on to carry out photocatalytic reaction, a tungsten lamp light source with a 400nm cut-off filter is used as a visible light source, the illumination intensity of the light source is 100mW / cm2. After the reaction is completed, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 61%.

[0070] Comparative Example 2

[0071] Compared with Example 1, the difference of Comparative Example 2 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0:0.

[0072] After the reaction is completed, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 69%.

[0073] Comparative Example 3

[0074] Compared with Example 1, the difference of Comparative Example 3 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0.05:1.

[0075] After the reaction is completed, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 74%.

[0076] Comparative Example 4

[0077] Compared with Example 1, the difference of Comparative Example 4 is that the mass ratio of AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in S102 is 1:0.8:3.

[0078] After the reaction is completed, the concentration of tetracycline antibiotics in the water body is determined by high performance liquid chromatography, and the degradation rate is calculated to be 71%.

[0079] From the examples and comparative examples, it can be seen that the AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO in the application can effectively improve the degradation rate of tetracycline antibiotics in water in the synergistic cooperation of a suitable mass ratio.

[0080] The above merely describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

[0081] For those skilled in the art, according to the idea of the present application, there will be changes in specific embodiments and application scope, and the content of the specification should not be understood as a limitation of the present application.

Claims

1. A method for degrading tetracycline antibiotics in an aqueous body, characterized by, The method comprises the following steps: S101: preparing AgCl / MIL-100(Fe) MOF material: Dissolving an iron ion source and trimesic acid in water, and adjusting pH value to 4.5-5.5 to obtain a reaction solution; the molar ratio of iron ion in the iron ion source to the trimesic acid is (1.1-1.5):1; the iron ion source comprises FeCl3 4H2O and Fe(NO3)3 9H2O After the reaction liquid is stirred at 20-30 DEG C for 20-30 h, the MIL-100(Fe) is obtained after washing and drying; The MIL-100(Fe) is mixed with a silver ion solution, stirred for 2-5 h, then a chloride ion solution is added dropwise, and stirred for 5-10 h under natural light irradiation, and then washed and dried to obtain AgCl / MIL-100(Fe) MOF material; S102: photocatalytic degradation: The AgCl / MIL-100(Fe) MOF material, TiO2 and ZnO are mixed with a water body containing tetracycline antibiotics under dark conditions, the mass ratio of the AgCl / MIL-100(Fe) MOF material, the TiO2 and the ZnO is controlled to be 1:(0.1-0.5):(1.2-2.5), the mixed system is stirred in the dark for 0.5-1 h, then a light source is turned on for photocatalytic reaction, the light source is a visible light source, and the light intensity of the light source is 50-200 mW / cm2.

2. The method of degrading tetracycline antibiotics in an aqueous body as claimed in claim 1, wherein, The reaction temperature of the photocatalytic reaction is 20-30 DEG C, and the reaction time is 1-3 h.

3. The method for degrading tetracycline antibiotics in water as described in claim 1, characterized in that, The visible light source is a tungsten lamp light source with a 400 nm cut-off filter.

4. The method for degrading tetracycline antibiotics in water bodies according to any one of claims 1-3, wherein, The mass ratio of the AgCl / MIL-100(Fe) MOF material, the TiO2 and the ZnO is 1:0.3:

2.

5. The method for degrading tetracycline antibiotics in water bodies according to any one of claims 1-3, wherein, The molar concentration of silver ions in the silver ion solution is 50-60 mmol / L.

6. The method for degrading tetracycline antibiotics in water bodies according to any one of claims 1 to 3, wherein, The molar concentration of chloride ions in the chloride ion solution is 10-15 mmol / L.

7. The method of degrading tetracycline antibiotics in an aqueous body as claimed in any one of claims 1 to 3 wherein, The volume ratio of the silver ion solution to the chloride ion solution is 1:(3-5).

8. The method for degrading tetracycline antibiotics in water as described in any one of claims 1-3, characterized in that, The mass ratio of the MIL-100(Fe) to silver ions in the silver ion solution is (1.1-1.3):1.