Method for efficiently degrading antibiotics in water based on vacuum ultraviolet rays under preset reaction conditions

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a method for efficiently degrading antibiotics in water based on vacuum ultraviolet under a preset reaction condition, which comprises the following steps: adding a sample water body containing the antibiotics into a sample container of a photoreaction device, opening a magnetic stirrer, and carrying out photoreaction; the liquid in the sample container is uniformly mixed under the action of rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water body is 3.0-5.0; hydrogen peroxide and a FeCl3 stock solution are added into the sample container, so that the sample water body reaches preset reaction conditions; opening the peristaltic pump, pumping the reaction liquid in the sample container into the annular reaction layer under the action of the peristaltic pump, and reacting under the irradiation of the vacuum ultraviolet lamp or the ultraviolet lamp to degrade the antibiotics in the sample water body.

Description

Technical Field

[0001] The present application belongs to the field of water treatment technology, and specifically relates to a method for efficiently degrading antibiotics in water based on vacuum ultraviolet rays under preset reaction conditions. Background Art

[0002] Since most antibiotics are highly water-soluble and chemically stable, it is difficult to effectively remove them using traditional water treatment technologies.

[0003] The development of efficient treatment technology is particularly important for achieving effective removal of antibiotics in aquatic environments and thus reducing their harm to the aquatic environment and human health. Advanced oxidation technology (AOPs) is a highly efficient water treatment technology that can generate hydroxyl radicals (HO ● ), thereby removing refractory organic pollutants from water. VUV / UV can be used as an efficient light source for UV-based AOPs.

[0004] At present, there is relatively little research on vacuum ultraviolet (VUV) technology for degrading antibiotics in water in the field of water treatment, and the impact of different influencing factors on pollutant removal has not yet been clearly determined, which limits the promotion and application of related technologies. Summary of the invention

[0005] The present application provides a method for efficiently degrading antibiotics in water based on vacuum ultraviolet rays under preset reaction conditions, which can solve the problem that in the prior art, there is relatively little research on VUV degradation of antibiotics in water in the field of water treatment, which limits the promotion and application of related technologies.

[0006] The present application provides a method for efficiently degrading antibiotics in water based on vacuum ultraviolet light under preset reaction conditions, comprising:

[0007] Add the sample water containing antibiotics into the sample container of the photoreaction device, turn on the magnetic stirrer, and mix the liquid in the sample container evenly under the action of the rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water is 3.0-5.0;

[0008] Add hydrogen peroxide and FeCl3 stock solution into the sample container so that the sample water reaches the preset reaction conditions;

[0009] Turn on the peristaltic pump, and the reaction liquid in the sample container is pumped into the annular reaction layer under the action of the peristaltic pump, and reacts under the irradiation of VUV or ultraviolet (UV) lamp to degrade the antibiotics in the sample water;

[0010] The photoreaction device comprises: a photoreactor, a liquid circulation system and a constant temperature water bath layer; the photoreactor comprises: a detachable light source, a high-purity quartz annular reaction layer, a top cover body and a bottom cover body; the top and bottom of the photoreactor are respectively provided with a top cover body and a bottom cover body, and a detachable light source is vertically arranged in the photoreactor; the detachable light source and the top cover body are detachably fixed; a constant temperature water bath layer is sleeved on the outer side of the photoreactor; the liquid circulation system comprises: a magnetic stirrer, a liquid outlet pipe, a liquid return pipe and a sample container, one end of the liquid outlet pipe is connected to the sample container, the other end of the liquid outlet pipe is detachably connected to the high-purity quartz annular reaction layer, one end of the liquid return pipe is connected to the sample container, and the other end of the liquid return pipe is detachably connected to the high-purity quartz annular reaction layer; the magnetic stirrer is used to place the sample container, a magnetic stirring rotor is placed in the sample container, and a peristaltic pump is connected to the middle part of the liquid outlet pipe.

[0011] Optionally, the antibiotic in the sample water is sulfamethoxazole (SMN) with a concentration of 0.5 mg / L.

[0012] Optionally, the initial pH value of the sample water body is 4.0.

[0013] Optionally, the concentration of hydrogen peroxide in the sample water is 2.5 mg / L.

[0014] Optionally, Fe in the sample water 3+ The concentration is 1.4 mg / L.

[0015] Optionally, after the reaction is completed, the solution in the annular reaction layer is drained, and ultrapure water is injected to thoroughly clean the inlet and outlet connecting hoses and the inner wall of the annular reaction layer. After cleaning, the water in the connecting hose and the annular reaction layer is drained and the peristaltic pump is stopped.

[0016] Optionally, a sample is taken from the sample container by a disposable sampler at intervals of 120 seconds, and the concentration of SMN in the sample solution is measured and analyzed to obtain a degradation curve for removing SMN.

[0017] Optionally, before adding the sample water containing the antibiotic into the sample container of the photoreaction device, the method further comprises:

[0018] Installing a VUV or UV lamp to the photoreaction device; the detachable light source is a VUV or UV lamp;

[0019] Turn on the cooling circulator, pump ultrapure water into the constant temperature water bath through the cooling water inlet and discharge it back through the cooling water outlet;

[0020] Turn on the VUV or UV lamp of the photoreaction device to preheat the irradiation chamber;

[0021] Open the high-purity N2 gas cylinder, and continuously pass high-purity N2 into the irradiation chamber through the high-purity N2 inlet and discharge it from the high-purity N2 exhaust port, so that the irradiation chamber is filled with high-purity N2.

[0022] Optionally, the water temperature of the thermostatic water bath is kept constant at 25°C.

[0023] Optionally, the preheating time is more than 30 minutes.

[0024] In the embodiment of the present application, a sample water body containing antibiotics is added to the sample container of the photoreaction device, and the magnetic stirrer is turned on so that the liquid in the sample container is evenly mixed under the action of the rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water body is 3.0-5.0; hydrogen peroxide and FeCl3 stock solution are added to the sample container so that the sample water body reaches the preset reaction conditions; the peristaltic pump is turned on, and the reaction liquid in the sample container is pumped into the annular reaction layer under the action of the peristaltic pump, and reacts under the irradiation of a VUV lamp or a UV lamp to degrade the antibiotics in the sample water body. Based on the preset reaction conditions of the embodiment of the present application, the method of degrading antibiotics can be maximized to achieve cost reduction and efficiency improvement, and promote the popularization and application of related technologies. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic structural diagram of a photoreaction device provided in an embodiment of the present application;

[0026] Figure 2 is a SMN morphology distribution diagram provided in an embodiment of the present application;

[0027] Figure 3 This is a schematic diagram of the effect of the initial pH value of a sample water body on the degradation of antibiotics in water provided in an embodiment of the present application;

[0028] Figure 4 This is a schematic diagram of the effect of the antibiotic concentration in a sample water body on the degradation of antibiotics in the water provided in an embodiment of the present application;

[0029] Figure 5 The H2O2 and Fe content in a sample water provided in the embodiment of the present application is 3+ Schematic diagram of the effect of initial concentration on the degradation of antibiotics in water. DETAILED DESCRIPTION

[0030] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0031] The embodiments of the present application can be applied to at least the following scenarios, which are described in detail below:

[0032] In the past few decades, antibiotics frequently detected in the environment have attracted widespread attention as a serious threat to the ecological safety of water bodies. At present, antibiotics are mainly discharged into the water environment through multiple sources such as municipal sewage treatment plants, centralized livestock farms, hospitals, pharmaceutical factories and chemical plants. Since most antibiotics (such as sulfonamides and fluoroquinolone antibiotics) are highly water-soluble and chemically stable, it is difficult to effectively remove them using traditional water treatment technologies (such as coagulation-flocculation, adsorption and precipitation).

[0033] As a typical sulfonamide antibiotic, SMN has the advantages of a wide antibacterial spectrum, strong bactericidal power, and low price. Since SMN is widely used to treat human and animal diseases, it can be detected in many water environments around the world, with concentrations reaching ng / L-μg / L. So far, although no research has reported that SMN will have obvious toxic side effects on human health, some scholars have found that its long-term use will lead to high bacterial resistance and potential bioaccumulation and persistence. Therefore, the development of efficient treatment technology is particularly important to achieve the effective removal of antibiotics in the water environment, thereby reducing its harm to the water environment and human health.

[0034] AOPs is a highly efficient water treatment technology that can generate high redox potential and strong oxidizing HO in situ. ● As a widely used AOP, photo-Fenton technology (λ<400nm) can reduce Fe 3+ The complex is Fe 2+ , thereby promoting the generation of reactive oxygen species (ROSs) and inhibiting the precipitation of iron. The main chemical reactions involved in the photo-Fenton technology are shown in equations 1-6:

[0035] Fe 2+ +H2O2→Fe 3+ +HO · +OH - (1)

[0036] Fe 3+ +H2O2→Fe 2+ +HO2 · +H + (2)

[0037] HO2 · +Fe 3+ →Fe 2+ +O2+H + (3)

[0038] HO · +Fe 2+ →Fe3+ +OH - (4)

[0039] HO · +H2O2→HO2 · +H2O (5)

[0040] [Fe(OH)] 2+ +hv <400 →Fe 2+ +HO · (6)

[0041] Since H2O can be photolyzed by VUV to generate HO ● , hydrogen radical (H ● ) and hydrated electrons As shown in equations (7) to (8), VUV is also considered to be an AOP that can remove organic pollutants in water.

[0042] H2O+hv 185 →HO · +H · (7)

[0043]

[0044] As the most common UV light source, low-pressure mercury lamps can simultaneously emit 185nm and 254nm photons (i.e., VUV / UV), thereby directly photolyzing and indirectly oxidizing organic pollutants in water. When VUV or UV lamps replace traditional UV mercury lamps as light sources, VUV / UV / chlorine has a higher efficiency in removing organic pollutants than UV / chlorine technology, which is mainly due to the additional HO ● The generation and synergistic effects are jointly led to.

[0045] Therefore, VUV / UV can be used as an efficient light source for UV-based AOPs (UV-AOPs). At present, there are relatively few studies on VUV / UV / Fenton (VPF) technology in the field of water treatment, so it is very meaningful to explore its removal of organic pollutants in water.

[0046] In order to facilitate the explanation of the method provided by the present application for efficiently degrading antibiotics in water based on vacuum ultraviolet rays under preset reaction conditions, the photoreaction device used in the method of the present application is described below:

[0047] like Figure 1 As shown, this embodiment provides a light reaction device, including:

[0048] Photoreactor 10, liquid circulation system 20 and constant temperature water bath layer 30;

[0049] The photoreactor 10 includes: a detachable light source 11, a high-purity quartz annular reaction layer 12, a top cover 13, and a bottom cover 14;

[0050] A top cover 13 and a bottom cover 14 are respectively disposed at the top and bottom of the photoreactor 10, and a detachable light source 11 is vertically disposed inside the photoreactor; the detachable light source 11 is detachably fixed to the top cover 13;

[0051] The outer side of the photoreactor is provided with a constant temperature water bath layer 30;

[0052] The liquid circulation system 20 includes: a liquid outlet pipe 21, a liquid return pipe 22 and a sample container 23. One end of the liquid outlet pipe 21 is connected to the sample container 23, and the other end of the liquid outlet pipe 21 is detachably connected to the high-purity quartz annular reaction layer 12. One end of the liquid return pipe 22 is connected to the sample container 23, and the other end of the liquid return pipe 22 is detachably connected to the high-purity quartz annular reaction layer 12.

[0053] The detachable light source 11 refers to a light source inside the photoreactor that can be easily disassembled and replaced, such as a UV lamp or a light-emitting diode lamp, etc., which is convenient for maintenance and optimization of the light source and improves the flexibility and adaptability of the system.

[0054] The high-purity quartz annular reaction layer 12 is the main reaction area for placing photocatalysts or samples inside the photoreactor 10. The light emitted by the detachable light source 11 irradiates the high-purity quartz annular reaction layer 12 to stimulate the photocatalytic reaction or directly act on the sample.

[0055] In the embodiment of the present application, on the one hand, the high-purity quartz annular reaction layer 12 can make the structure of the entire photoreaction device more compact and stable, which can not only reduce the volume of the photoreaction device, but also facilitate the transportation of the device and extend the service life of the photoreaction device.

[0056] On the other hand, compared with traditional high-purity quartz capillary tubes, the volume of the high-purity quartz annular reaction layer is significantly larger, which can increase the irradiation area of ​​the light source and the utilization efficiency of photons, reduce the cost of sewage treatment, and improve the efficiency of sewage treatment.

[0057] In addition, the high-purity quartz annular reaction layer can increase the amount of wastewater treated in a single test, so that each sampling in the detection process has little or even negligible impact on the total volume of the reaction solution, ensuring the scientificity and accuracy of the experimental results.

[0058] Furthermore, the high-purity quartz annular reaction layer can significantly increase the amount of wastewater treated per unit time, laying a good foundation for the practical promotion and application of related water treatment technologies in the future.

[0059] The top cover and bottom cover refer to the closed covers at the upper and lower ends of the photoreactor, which play the role of sealing the internal environment of the reactor and controlling the temperature and other conditions.

[0060] The detachable light source and the top cover body are detachably fixed, which means that the light source, reaction layer and other components are detachably connected to the cover body, so that it is easy to open the photoreactor to perform operations such as light source maintenance.

[0061] In the embodiments of the present application, the annular reaction interlayer structure is stable, and the switching and updating of different detachable light sources can be easily achieved. By comparing the treatment effects of pollutants under different light sources, the mechanism can be explored.

[0062] The constant temperature water bath layer is a temperature-controlled water bath system arranged outside the photoreactor. Through the constant temperature water bath layer, the temperature conditions inside the reactor can be accurately controlled.

[0063] The liquid circulation system is a circulating flow system composed of a liquid outlet pipe, a liquid return pipe and a sample container, which can realize the continuous circulation of the reaction liquid between the reaction layer and the collection container, thereby improving the throughput of sample processing.

[0064] A high-purity nitrogen inlet pipe 15 and a high-purity nitrogen exhaust pipe 16 are respectively arranged on the photoreactor. The high-purity nitrogen inlet pipe 15 is connected to a high-purity nitrogen bottle, and the high-purity nitrogen exhaust pipe 16 is connected to the outside air.

[0065] The high-purity nitrogen gas inlet pipe 15 is connected to the high-purity nitrogen gas bottle, and high-purity nitrogen gas can be introduced into the interior of the photoreactor through the high-purity nitrogen gas inlet pipe 15.

[0066] The high-purity nitrogen exhaust pipe 16 is connected to the outside air. Through the high-purity nitrogen exhaust pipe 16, the gas inside the photoreactor can be discharged into the outside air.

[0067] By continuously supplying high-purity nitrogen into the reactor, active gases such as oxygen in the air can be removed, providing a reaction environment and supporting the reaction process.

[0068] The middle part of the liquid outlet pipe is connected with a peristaltic pump 24, and the flow rate of the peristaltic pump is 600-1200mL / min.

[0069] The peristaltic pump 24 can accurately control the flow rate of the liquid outlet to meet the liquid delivery requirements during the reaction process. The working principle of the peristaltic pump 24 is to produce a continuous, pulsation-free delivery effect by squeezing the hose through the roller, which can maintain the stable flow of the liquid in the liquid outlet pipe and avoid fluctuations in the flow rate, which is conducive to the smooth progress of the reaction process.

[0070] When the pressure in the reactor changes, the peristaltic pump 24 can prevent the liquid from flowing back into the reactor, thereby ensuring the stability of the reaction process. As an intermediate component of the liquid outlet pipe 21, the peristaltic pump 24 can be easily maintained and replaced, thereby improving the reliability of the entire system.

[0071] Wherein, the liquid circulation system 20 further includes:

[0072] The magnetic stirrer 25 is used to place the sample container 23 , and a magnetic stirring rotor is placed in the sample container 23 .

[0073] The magnetic stirrer 25 generates a controllable magnetic field to drive the magnetic stirring rotor inside the container to rotate, thereby achieving continuous stirring of the substances inside the sample container and increasing the contact and mixing between the reactants.

[0074] The sample container 23 is used to hold the raw materials or reactants that need to undergo photoreaction, and a magnetic stirring rotor is placed inside the container 23. When the magnetic stirring rotor is placed inside the sample container, it will rotate under the action of the external magnetic stirrer, thereby driving the reactants inside the container to mix.

[0075] Among them, a water outlet and a water inlet are respectively arranged at the top and bottom of the constant temperature water bath layer. The water outlet of the constant temperature water bath layer is connected to the water inlet of the cooling circulator through an outlet pipe, and the water outlet of the cooling circulator is connected to the water inlet of the constant temperature water bath layer through an inlet pipe.

[0076] The constant temperature water bath layer can maintain a constant temperature inside the water bath layer through continuous water inlet and outlet, providing a stable temperature environment for the photoreaction process. The outlet pipe and the inlet pipe form a closed circulating water circuit, connecting the constant temperature water bath layer with the cooling circulator. The cooling circulator can control the temperature of the circulating water and feed it back to the constant temperature water bath layer to maintain a constant temperature condition inside the photoreactor.

[0077] The coordinated work of the constant temperature water bath layer, circulation pipeline and cooling circulator provides precise temperature control for the photoreaction process, ensuring that the reaction can proceed at the optimal temperature.

[0078] The following is a description of a method for efficiently degrading antibiotics in water based on vacuum ultraviolet rays under preset reaction conditions provided in this application:

[0079] First, prepare the experimental materials:

[0080] All chemicals were of reagent grade or above and were not further purified before use. All solutions were prepared with ultrapure water (resistivity > 18.2 MΩcm).

[0081] The chemical structure of SMN is: The chemical formula is C 12 H14 N4O2S, molecular weight is 278.33, morphological distribution is as follows Figure 2 As shown, the octanol-water partition coefficient is 0.19. FeCl3·6H2O and H2O2 (30%, w / w) are Fenton's reagents.

[0082] The initial pH of the solution was adjusted with 0.1 M NaOH and HCl. Sodium salts (NaNO3, NaHCO3 and NaCl) and humic acid were used as donors of inorganic anions and natural organic matter, respectively. Chromatographically pure acetonitrile, methanol and formic acid were used as mobile phases for ultra-high performance liquid chromatography-tandem mass spectrometry analysis.

[0083] Experimental preparation stage:

[0084] Step 110, before adding the sample water containing the antibiotic into the sample container of the photoreaction device, the method further includes:

[0085] Step 120, installing a VUV or UV lamp to the photoreaction device; the detachable light source is a VUV or UV lamp;

[0086] Step 130, turn on the cooling circulator, pump ultrapure water into the constant temperature water bath layer through the cooling water inlet and discharge it from the cooling water outlet for reflux;

[0087] Step 140, turning on the VUV or UV lamp of the photoreaction device to preheat the irradiation chamber;

[0088] Step 150, open the high-purity N2 gas cylinder, continuously pass the high-purity N2 into the irradiation chamber through the high-purity N2 gas inlet and discharge it from the high-purity N2 exhaust port, so that the irradiation chamber is filled with high-purity N2.

[0089] Optionally, the water temperature of the thermostatic water bath is kept constant at 25°C.

[0090] Optionally, the preheating time is more than 30 minutes.

[0091] Involving the formal experimental stage:

[0092] Step 210, adding the sample water containing antibiotics into the sample container of the photoreaction device, turning on the magnetic stirrer, so that the liquid in the sample container is mixed evenly under the action of the rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water is 3.0-5.0;

[0093] Step 220, adding hydrogen peroxide and FeCl3 stock solution into the sample container so that the sample water body reaches the preset reaction conditions;

[0094] Step 230, turning on the peristaltic pump, the reaction liquid in the sample container is pumped into the annular reaction layer under the action of the peristaltic pump, and reacts under the irradiation of the VUV or UV lamp to degrade the antibiotics in the sample water;

[0095] The photoreaction device comprises: a photoreactor, a liquid circulation system and a constant temperature water bath layer; the photoreactor comprises: a detachable light source, a high-purity quartz annular reaction layer, a top cover body and a bottom cover body; the top and bottom of the photoreactor are respectively provided with a top cover body and a bottom cover body, and a detachable light source is vertically arranged in the photoreactor; the detachable light source and the top cover body are detachably fixed; a constant temperature water bath layer is sleeved on the outer side of the photoreactor; the liquid circulation system comprises: a magnetic stirrer, a liquid outlet pipe, a liquid return pipe and a sample container, one end of the liquid outlet pipe is connected to the sample container, the other end of the liquid outlet pipe is detachably connected to the high-purity quartz annular reaction layer, one end of the liquid return pipe is connected to the sample container, and the other end of the liquid return pipe is detachably connected to the high-purity quartz annular reaction layer; the magnetic stirrer is used to place the sample container, a magnetic stirring rotor is placed in the sample container, and a peristaltic pump is connected to the middle part of the liquid outlet pipe.

[0096] In the embodiment of the present application, a sample water body containing antibiotics is added to the sample container of the photoreaction device, and the magnetic stirrer is turned on so that the liquid in the sample container is evenly mixed under the action of the rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water body is 3.0-5.0; hydrogen peroxide and FeCl3 stock solution are added to the sample container so that the sample water body reaches the preset reaction conditions; the peristaltic pump is turned on, and the reaction liquid in the sample container is pumped into the annular reaction layer under the action of the peristaltic pump, and reacts under the irradiation of VUV or UV lamp to degrade the antibiotics in the sample water body. Based on the preset reaction conditions of the embodiment of the present application, the method of degrading antibiotics can be maximized to achieve cost reduction and efficiency improvement.

[0097] Embodiment 1:

[0098] Step 210, adding the sample water containing antibiotics into the sample container of the photoreaction device, turning on the magnetic stirrer, so that the liquid in the sample container is mixed evenly under the action of the rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water is 4.0;

[0099] Step 220, adding hydrogen peroxide and FeCl3 stock solution into the sample container so that the sample water body reaches the preset reaction conditions;

[0100] Step 230, turning on the peristaltic pump, the reaction liquid in the sample container is pumped into the annular reaction layer under the action of the peristaltic pump, and reacts under the irradiation of the VUV or UV lamp to degrade the antibiotics in the sample water.

[0101] Optionally, a sample is taken from the sample container by a disposable sampler at intervals of 120 seconds, and the concentration of SMN in the sample solution is measured and analyzed to obtain a degradation curve for removing SMN.

[0102] The experimental operation procedures for studying the degradation of SMN by VPF technology at other initial pH values ​​are basically the same as those described above. It is only necessary to adjust the initial pH to a preset value (such as 3.0, 4.0, 5.0, and 6.0) using 0.1 M NaOH and HCl. Specifically:

[0103] Embodiment 2:

[0104] The initial pH value of the sample water body is 3.0; the remaining steps are the same as those in Example 1.

[0105] Embodiment three:

[0106] The initial pH value of the sample water body is 5.0; the remaining steps are the same as those in Example 1.

[0107] Embodiment 4:

[0108] The initial pH value of the sample water body is 6.0; the remaining steps are the same as those in Example 1.

[0109] The analysis method used for the results of Example 1 to Example 4 may specifically include the following steps:

[0110] In the samples collected at set time intervals, excessive NaHSO3 is quickly added to eliminate the residual oxidant after the reaction, thereby ensuring the accuracy of the test data after the experiment. The pH of the solution is measured using a pH meter.

[0111] The H2O2 concentration was determined by titanyl sulfate spectrophotometry with a detection wavelength of 410 nm and a detection limit of 2.9×10 -4 mM.Fe 2+ The concentration was determined by o-phenanthroline spectrophotometry with a detection wavelength of 510 nm. The SMN concentration was determined by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS / MS).

[0112] The mobile phase was a mixture of 0.2% (w / w) formic acid solution (65%) and acetonitrile (35%) at a flow rate of 0.3 mL / min. The column oven was set at 30°C and the injection volume was 5.0 μL. The main operating conditions of the mass spectrometer were as follows: positive ion electrospray ionization mode, capillary voltage of 4.0 kV, drying gas temperature of 300°C, drying gas flow rate of 12 L / min, and spray pressure of 40 psi.

[0113] The parent ion (m / z) was 279.3; the two daughter ions (m / z) were 92.0 and 186.0, respectively, with corresponding collision energies of 35 and 10 eV, respectively; the fragmentation voltage was 115 V. The retention time of SMN was 1.32 min, and the limit of quantification was 1.80 nM.

[0114] Experimental results of Example 1-Example 4:

[0115] In order to understand the effect of the initial pH of the solution on the degradation of SMN, considering that the buffer reagent will quench ROSs or react with Fe 3+ / Fe 2 + The reaction generates a complex, so the examples of the present application only use NaOH and HCl solutions to adjust the pH of the reaction system.

[0116] Effect of initial solution pH on SMN degradation by VPS technology Figure 3 As shown in Figure 2, where k represents the degradation rate constant. Under acidic conditions, Fe 3+ The main soluble form is [Fe(OH)(H2O)5] 2+ Although [Fe(OH)(H2O)5] 2+ The photoreactivity is highest at pH 3.0, but the k VPF The maximum is reached at pH 4.0, which is mainly due to the following two reasons:

[0117] First, as pH decreases, H+ reacts with HO ● The quenching effect of SMN is increased; on the other hand, 0 and anionic SMN (SMN - ) is more difficult to be HO ● The proportion of cationic SMN (SMN+) subjected to electrophilic attack increases;

[0118] Second, as pH increases, on the one hand On the other hand, it is smaller than Fe 3+ and Fe 2+ The generation of iron hydroxides with lower catalytic activity (such as Fe(OH)3 and Fe(OH)2) is accelerated and their proportion increases. Based on the above results, 4.0 is the optimal pH for VPF technology to degrade SMN.

[0119] Optionally, based on Figure 3 In the experimental results shown, the initial pH value of the sample water was 4.0.

[0120] When the initial solution pH was 4.0, the SMN, H2O2 or Fe 3+The experimental operation process of the effect of initial concentration on SMN degradation is basically the same as above. It is only necessary to control the initial value of the dependent variable to the preset value through the control variable method. Specifically:

[0121] Embodiment five:

[0122] The SMN concentration in the sample water is adjusted to a preset SMN concentration value; the remaining steps are the same as those in Example 1.

[0123] Effect of initial SMN concentration on degradation of SMN by VPF technology Figure 4 The results show that k VPF As the SMN concentration increases, k VPF Reduced from 3897 to 1325m 2 einstein -1 This is because higher concentrations of SMN absorb more UV and VUV photons, which in turn causes other solution components (such as [Fe(OH)] 2+ , H2O and H2O2 absorb photons in a decreasing proportion.

[0124] In short, changes in the initial SMN concentration will affect the UV and VUV photon absorption distribution in the reaction solution and ultimately lead to different degradation mechanisms, that is, the contribution of direct photolysis and indirect oxidation to SMN degradation varies with the change of the initial SMN concentration.

[0125] Optionally, based on Figure 4 According to the experimental results shown, the concentration of SMN in the sample water is 0.5 mg / L.

[0126] Embodiment six:

[0127] The H2O2 concentration in the sample water is adjusted to a preset H2O2 concentration value; the remaining steps are the same as those in Example 1.

[0128] A Deeper Understanding of H2O2 and Fe 3+ The role played by H2O2 and Fe in the degradation of SMN by VPF technology helps to optimize the dosage of Fenton reagent. 3+ Effect of initial concentration on SMN degradation by VPF technology Figure 5 As shown in Figure 2, when the H2O2 concentration increases from 2.9μM to 2.9mM, k VPF It first increased and then decreased and reached the maximum value when the H2O2 concentration was 0.29 mM.

[0129] This is because as the concentration of H2O2 increases, it can promote the ● On the other hand, H2O2 itself acts as a quencher to accelerate the generation of HO ●consumption.

[0130] Optionally, based on Figure 5 The experimental results shown show that the concentration of H2O2 in the sample water is 2.5 mg / L.

[0131] Embodiment seven:

[0132] Adjust Fe in sample water 3+ The concentration is preset Fe 3+ The remaining steps are the same as those in Example 1.

[0133] In contrast, when Fe 3+ When the concentration increases from 1.0 μM to 0.5 mM, k VPF Gradually increased from 2056 to 6643m 2 einstein -1 This is due to the increase in Fe 3+ The concentration accelerated the Fe 3+ / Fe 2+ Redox cycling and generation of ROSs.

[0134] Optionally, based on Figure 5 The experimental results shown in the figure show that Fe in the sample water 3+ The concentration is 1.4 mg / L.

[0135] Optionally, after the reaction is completed, the solution in the annular reaction layer is drained, and ultrapure water is injected to thoroughly clean the inlet and outlet connecting hoses and the inner wall of the annular reaction layer. After cleaning, the water in the connecting hose and the annular reaction layer is drained and the peristaltic pump is stopped.

Claims

1. A method for efficiently degrading antibiotics in water based on vacuum ultraviolet light under preset reaction conditions, characterized in that: include: Add the sample water containing antibiotics into the sample container of the photoreaction device, turn on the magnetic stirrer, and mix the liquid in the sample container evenly under the action of the rapid rotation of the magnetic stirring rotor; the initial pH value of the sample water is 3.0-5.0; Add hydrogen peroxide and FeCl3 stock solution into the sample container so that the sample water reaches the preset reaction conditions; Turn on the peristaltic pump, and the reaction liquid in the sample container is pumped into the annular reaction layer under the action of the peristaltic pump, and reacts under the irradiation of vacuum ultraviolet light VUV or ultraviolet light UV to degrade the antibiotics in the sample water; The photoreaction device comprises: a photoreactor, a liquid circulation system and a constant temperature water bath layer; the photoreactor comprises: a detachable light source, a high-purity quartz annular reaction layer, a top cover body and a bottom cover body; the top and bottom of the photoreactor are respectively provided with a top cover body and a bottom cover body, and a detachable light source is vertically arranged in the photoreactor; the detachable light source and the top cover body are detachably fixed; a constant temperature water bath layer is sleeved on the outer side of the photoreactor; the liquid circulation system comprises: a magnetic stirrer, a liquid outlet pipe, a liquid return pipe and a sample container, one end of the liquid outlet pipe is connected to the sample container, the other end of the liquid outlet pipe is detachably connected to the high-purity quartz annular reaction layer, one end of the liquid return pipe is connected to the sample container, and the other end of the liquid return pipe is detachably connected to the high-purity quartz annular reaction layer; the magnetic stirrer is used to place the sample container, a magnetic stirring rotor is placed in the sample container, and a peristaltic pump is connected to the middle part of the liquid outlet pipe.

2. The method according to claim 1, characterized in that The antibiotic in the sample water is sulfamethoxazole SMN, with a concentration of 0.5 mg / L.

3. The method according to claim 1, characterized in that The initial pH value of the sample water was 4.

0.

4. The method according to claim 1, characterized in that: The concentration of hydrogen peroxide in the sample water is 2.5 mg / L.

5. The method according to claim 1, characterized in that Fe in sample water 3+ The concentration is 1.4 mg / L.

6. The method according to claim 1, characterized in that The method further comprises: After the reaction is completed, the solution in the annular reaction layer is drained, and ultrapure water is injected to thoroughly clean the inlet and outlet connecting hoses and the inner wall of the annular reaction layer. After cleaning, the water in the connecting hose and the annular reaction layer is drained and the peristaltic pump is stopped.

7. The method according to claim 2, characterized in that The method further comprises: Every 120 seconds, a disposable sampler was used to take samples from the sample container, and the concentration of SMN in the sample solution was determined and analyzed to obtain a degradation curve for removing SMN.

8. The method according to claim 1, characterized in that Before adding the sample water containing the antibiotics into the sample container of the photoreaction device, the method further comprises: Installing a VUV or UV lamp to the photoreaction device; the detachable light source is a VUV or UV lamp; Turn on the cooling circulator, pump ultrapure water into the constant temperature water bath through the cooling water inlet and discharge it back through the cooling water outlet; Turn on the VUV or UV lamp of the photoreaction device to preheat the irradiation chamber; Open the high-purity N2 gas cylinder, and continuously pass high-purity N2 into the irradiation chamber through the high-purity N2 inlet and discharge it from the high-purity N2 exhaust port, so that the irradiation chamber is filled with high-purity N2.

9. The method according to claim 8, characterized in that The water temperature of the thermostatic water bath was kept constant at 25°C.

10. The method according to claim 8, characterized in that The preheating time is more than 30 minutes.

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