Method and reactor for treating tetracycline wastewater

Abstract

The invention discloses a method and a reactor for treating tetracycline wastewater. The method comprises the following steps: preparing an iron-nitrogen doped porous carbon material catalyst, adding the catalyst and operating the reactor. The efficient denitrification reaction is completed through three processes, namely a water inlet reaction process, a stirring degradation process and a static settling drainage process. The reactor structurally comprises a reaction cavity, a bacterial biological aggregation membrane, a dosing system, a stirring system and the like. The iron-nitrogen-doped porous carbon material catalyst is adopted, PMS is activated under the action of the catalyst to remove tetracycline, and the method has the advantages that secondary pollution is avoided, the catalyst is not prone to loss, the degradation efficiency is high, the cost is low, and operation and management are easy.

Description

Technical Field

[0001] The invention belongs to the field of water pollution treatment in environmental engineering, and in particular relates to a method for treating tetracycline wastewater and a reactor. Background Art

[0002] Studies have shown that TC remaining in the water environment can affect the production pathway of steroids, leading to endocrine disorders and chronic toxicity in aquatic organisms, thereby endangering the lives of aquatic species and ultimately harming human health through the food chain. Therefore, it is of great significance to develop a purification technology that can efficiently remove TC pollutants from wastewater.

[0003] The widespread presence of TC pollutants in water bodies has attracted widespread attention. In order to achieve the removal of TC pollutants, a variety of treatment technologies and methods have been developed. Among them, persulfate-based AOPs can produce active oxygen free radicals with strong oxidizing ability under reaction conditions such as high temperature and high pressure, light irradiation, ultrasound, electrocatalysis and catalysts, oxidizing difficult-to-degrade macromolecular organic matter into low-toxic or non-toxic small molecules. Compared with other oxidants, persulfate-based AOPs are inexpensive, require lower dissociation activation energy, and have higher solubility and stability in water, making them the first choice for treating tetracycline contamination in water.

[0004] According to previous studies, the activation methods of persulfate include homogeneous activation and heterogeneous activation. Among them, the materials used for heterogeneous activation mainly include transition metal oxides and carbon-based materials (activated carbon, graphene, carbon nanotubes and biochar, etc.). At present, the traditional persulfate system advanced oxidation degradation technology has the following pain points: First, some metal catalysts (such as Co, Mn and Cu, etc.) have the risk of ion leakage, which may cause secondary pollution of water bodies. Second, the existing treatment structures cannot be well adapted to tetracycline wastewater, and traditional advanced oxidation structures need to add a mixed liquor reflux system. Third, the cost is high and the operation is complex. The requirements are relatively stringent, and there are disadvantages of high cost and complex operation. Summary of the invention

[0005] In view of the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide a method and reactor for treating tetracycline wastewater, taking TC as the target pollutant, designing a stable and efficient new Fe-NC heterogeneous catalytic material as the core, constructing an efficient PMS catalytic system, realizing the rapid removal of TC pollutants in the environment, and undergoing the water inlet reaction process, stirring process and drainage and bacteria addition process to carry out efficient tetracycline degradation reaction. This technology is a treatment method that can achieve efficient treatment of tetracycline, no secondary pollution, and the catalyst is immobilized and not easy to lose.

[0006] To achieve the above-mentioned object of the invention, the present invention provides a method for treating tetracycline wastewater and a reactor, which comprises the following steps:

[0007] Step 1, catalyst preparation,

[0008] Take a certain mass (M = 0.01-0.1g) of FeCl2·4H2O and dissolve it in 1-100mL deionized water, then add 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 and stir continuously at room temperature for 30 minutes, then evenly disperse 0.1-1g CS powder in the above solution and add 2% volume ratio of acidic solution to fully dissolve it to form a uniform viscous solution. Under continuous stirring, slowly add 1M NaOH solution to the above viscous solution until the hydrogel is completely formed. After the gelation process is completed, rinse the hydrogel repeatedly with deionized water until a neutral pH value is reached. Subsequently, place the gel in a -80℃ refrigerator and freeze overnight, and then use a vacuum freeze dryer to remove all moisture. Finally, place the above sample in a tubular furnace and condense it at 5℃min in an Ar atmosphere. -1 The temperature was raised to a specified temperature (500-1000°C) at a rate and maintained for calcination for 2h to obtain an iron-nitrogen doped porous carbon material.

[0009] Step 2: Addition of catalyst:

[0010] The degradation experiment was carried out in the reactor. First, the catalyst medicine can on the stirring paddle was moved out of the reaction chamber by the stirring device. Then 0.5-1g of the material prepared in step 1 was transferred into the catalyst medicine can on the stirring paddle. Then, the catalyst medicine can was installed on the stirring paddle, and finally, the catalyst medicine can was pulled into the reaction chamber by the motor system.

[0011] Step 3: Reactor operation.

[0012] Add the filter tank to the wastewater, turn on the agitator, and stir the filter tank in the reaction chamber driven by the power system, and react for 15 minutes with stirring. After the reaction, open the drain to complete the tetracycline degradation treatment of the wastewater. By adopting this technical solution, the iron metal is fully loaded in the reduced graphene oxide material, and the obtained substance has a high catalytic efficiency for persulfate. The catalyst has the advantages of simple preparation process, low cost, and short degradation cycle.

[0013] For the above technical solution, the present invention has a further preferred solution:

[0014] Preferably, in step 1, the mass of FeCl2·4H2O is 0-0.5g, the mass of 1,10-phenanthroline is 0-1g, the mass of chitosan (CS) is 0-0.5g, the volume fraction of the acidic solution is 0-10%, the concentration of the sodium hydroxide solution is 0-2M, and the capacity is 1-1000ml.

[0015] Preferably, the freeze drying in step 1 includes freezing in a -80°C refrigerator for 1-24 hours and drying in a vacuum freeze dryer at -40°C for 1-24 hours.

[0016] Preferably, the catalyst calcination temperature in step 1 is 500-1000°C, and the temperature is maintained for 1-3 hours after reaching the highest calcination temperature. The heating rate is set at 5-15°C·min -1 , the inert gas is argon or nitrogen.

[0017] Preferably, in step 2, the operation of the reactor includes:

[0018] Water inlet reaction: transfer persulfate into the reaction chamber through the dosing device, put the catalyst into the catalyst tank, and then let the water to be treated enter the reaction chamber;

[0019] Turn on the agitator at a speed of 200-600rpm. After 15 minutes of reaction, turn on the water inlet and outlet systems at the same time, the treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated;

[0020] Stop the water supply, take out the catalyst medicine tank on the stirring device, replace the catalyst, and then reload it into the reaction chamber, repeat the experiment, and further treat the tetracycline wastewater.

[0021] The present invention further provides a reactor used in the above method, comprising a cylindrical reaction chamber, a water inlet system, a water outlet system, a catalyst medicine tank, a stirring device, a motor system and a dosing device are sequentially arranged on the water inlet connecting pipeline of the reaction chamber, and a water outlet is arranged on the middle side wall of the reaction tank. It is used to activate persulfate to degrade tetracycline and tetracycline residues in sewage and wastewater, and preferably, the persulfate includes one or a mixture of two of potassium persulfate, ammonium persulfate and potassium hydrogen persulfate composite salt.

[0022] The present invention also discloses a method for degrading tetracycline antibiotics by using activated persulfate advanced oxidation technology, wherein a solution containing tetracycline antibiotics is mixed with persulfate, and then the Fe2+Phen coordinated iron-nitrogen doped porous carbon catalyst is added to perform full degradation.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] First, by adopting the technical solution of the present invention, iron metal is fully loaded in chitosan material, and the obtained material has high catalytic efficiency for persulfate. The catalyst has the advantages of simple preparation process, low cost, short degradation cycle, etc., and the catalyst has strong anti-interference ability to multiple ions, strong cycle durability, and broad application prospects.

[0025] Second, compared with the traditional tetracycline degradation method, the present invention further adds PMS and iron-nitrogen doped porous carbon catalyst into the tetracycline wastewater in the reaction chamber to construct an efficient PMS catalytic system to achieve rapid removal of TC pollutants in the environment; since PS-AOPs can activate PMS to produce a variety of strong oxidizing active groups, induce the breaking of chemical bonds of organic matter, and degrade it into small molecules or even completely mineralize it into inorganic molecules, it has significant advantages in the degradation of TC in wastewater.

[0026] Third, the iron-nitrogen doped porous carbon catalyst has a good effect on activating peroxymonosulfate to degrade tetracycline wastewater. -1 , Tetracycline solution = 20 mg·L -1 Under the conditions of temperature = 25℃, tetracycline can be efficiently degraded within 15 minutes.

[0027] Fourth, the present invention draws on the normal temperature and pressure processing mode of advanced oxidation technology, which has the characteristics of small footprint, simple equipment, strong stability, high activity, long service life, and low energy consumption, and bids farewell to traditional processing devices with large footprint and high energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the structure of the reactor of the present invention.

[0029] Figure 2 Schematic diagram of TC degradation effect of the reactor of Example 1 and Example 2 of the present invention;

[0030] Figure 3 Schematic diagram of TC degradation effect of the reactor of Example 1 and Example 3 of the present invention;

[0031] Figure 4 Schematic diagram of TC degradation effect of the reactor of Example 1 and Example 4 of the present invention;

[0032] Figure 5 Schematic diagram of TC degradation effect of the reactors of Example 1, Example 5 and Example 6 of the present invention;

[0033] Figure 6 The reusability (A) and leaching of iron ions (B) of Example 1 of the present invention are tested

[0034] Numbers in the figure: 1-grid, 2-water inlet pump, 3-static mixer, 4-water inlet gate valve, 5-catalyst tank, 6-stirring device, 7-motor system, 8-water outlet gate valve. DETAILED DESCRIPTION

[0035] Below in conjunction with the drawings and Examples, the specific embodiments of the present invention are described in further detail. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Any parameters and data shown in the present invention are not limited to accurate ranges or values, but should be understood to include parameters and data close to these ranges or values.

[0036] like Figure 1 As shown, the present invention adopts a method for treating tetracycline wastewater and a reactor for tetracycline degradation treatment. The reactor includes a cylindrical reaction chamber, and a grid 1, a water inlet pump 2, a static mixer 3 and a water inlet gate valve 4 are arranged in sequence on the water inlet connecting pipeline of the reaction chamber. A stirring device 6 is installed above the reaction chamber, and is connected to a motor system 7. A catalyst medicine tank 5 with a 0.22μm polytetrafluoroethylene filter membrane is installed on the stirring paddle. A water outlet gate valve 8 is installed on the other side of the reaction chamber.

[0037] The method for treating tetracycline wastewater using the reactor of the present invention is provided below, comprising the following steps:

[0038] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0039] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0040] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to a specified temperature (500-1000°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0041] Step 2: Addition of catalyst:

[0042] The degradation experiment was carried out in the reactor. First, the catalyst medicine can on the stirring paddle was moved out of the reaction chamber by the stirring device. Then 0.5-1g of the material prepared in step 1 was transferred into the catalyst medicine can on the stirring paddle. Then, the catalyst medicine can was installed on the stirring paddle, and finally, the catalyst medicine can was pulled into the reaction chamber by the motor system.

[0043] Step 3: Run the reactor:

[0044] Transfer 0.1 g L into the catalyst tank -1 After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the water to be treated enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the water to be treated flows through the static reactor, 0.1-1mM PMS mixes with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. Stir and react for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0045] The operating mechanism is: the present invention is based on FeN x Catalyst activated PMS is an advanced oxidation technology used to degrade tetracycline wastewater. Persulfate and catalyst are added to the reaction chamber to perform efficient degradation reactions in tetracycline wastewater. In tetracycline wastewater, iron-nitrogen doped porous carbon catalyzes persulfate to produce highly oxidizing sulfate radicals (SO4 ·- )and · OH can attack the reaction sites of TC through a series of free radical chain reactions, causing it to undergo hydroxylation, bond breaking, and ring opening reactions and decompose into intermediate metabolites, which are finally mineralized into carbon dioxide and water, thereby performing an efficient tetracycline degradation reaction. Since the metal-carbon-based composite material has high activation efficiency and high stability as a catalyst, and can use its own structural characteristics to perform adsorption to remove pollutants in the water, it can then perform an efficient degradation reaction. At the same time, since transition metal activation of PS can be carried out under normal temperature and pressure conditions and does not require the input of additional energy, it is considered to be the most energy-saving and environmentally friendly activation method. Drawing on traditional advanced oxidation technology, the reaction process of the reactor of the present invention continuously performs the water inlet reaction process, the stirring process, and the drainage and dosing process. A stirring device is used to control the stirring rate and time so that the iron-nitrogen doped porous carbon particles can move up and down in the water body so as to fully contact and react with the water body. A static mixer and a grid are set at the water inlet. The grid is used to remove impurities in the inlet water to prevent damage to the stirring catalyst medicine tank. The static mixer is used to mix the PMS solution and the inlet water. The detachable medicine tank catalyst on the stirring device is used to replace the catalyst and recycle the used catalyst for regeneration to maintain a sufficient amount of catalyst in the reaction chamber.

[0046] FeN x The activation process related reactions are as follows

[0047] M + +HSO5 - →M (n+1)+ +SO4 ·- +OH -

[0048] M + +S2O8 2- →M (n+1)+ +SO4 ·- +SO4 2-

[0049] Under the action of iron-nitrogen doped porous carbon, HSO5 - is reduced to (SO4 ·- ) and ·OH to achieve efficient activation of persulfate.

[0050] The present invention is further illustrated by means of specific examples below.

[0051] Example 1

[0052] This example describes the effect of activating peroxymonosulfate with an iron-nitrogen doped porous carbon catalyst to degrade tetracycline wastewater. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operating steps of the reactor are as follows:

[0053] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0054] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0055] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to a specified temperature (500-1000°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0056] Step 2: Addition of catalyst:

[0057] The degradation experiment was carried out in the reactor. First, the catalyst pot on the stirring paddle was moved out of the reaction chamber through the stirring device. Then 0.1 g L -1 Materials prepared in step 1. Then the catalyst can is mounted on the stirring paddle, and finally the catalyst can is pulled into the reaction chamber by the motor system.

[0058] Step 3: Run the reactor:

[0059] Transfer 0.1 g L into the catalyst tank -1 After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the treated water enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the treated water flows through the static reactor, 0.5mM PMS is mixed with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. Stir and react for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0060] Example 2

[0061] This example describes the effect of activating peroxymonosulfate with an iron-nitrogen doped porous carbon catalyst to degrade tetracycline wastewater. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operating steps of the reactor are as follows:

[0062] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0063] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0064] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to a specified temperature (500-1000°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0065] Step 2: Addition of catalyst:

[0066] The degradation experiment was carried out in the reactor. First, the catalyst pot on the stirring paddle was moved out of the reaction chamber through the stirring device. Then 0.05 g L -1 , 0.2 g L -1 Materials prepared in step 1. Then the catalyst can is mounted on the stirring paddle, and finally the catalyst can is pulled into the reaction chamber by the motor system.

[0067] Step 3: Run the reactor:

[0068] Transfer 0.05 g L into the catalyst tank -1 , 0.2 g L -1After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the treated water enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the treated water flows through the static reactor, 0.5mM PMS is mixed with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. Stir and react for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0069] like Figure 2 It can be seen that as the PMS concentration increases from 0.25mM to 0.5mM, the TC removal rate increases from 75.4% to 90.7%, and the reaction rate increases from 0.115min -1 Increased to 0.184min -1 This may be due to the fact that PMS activation produces more ROS, which in turn leads to the rapid degradation of TC. When the PMS dose was further increased to 1 mM, the degradation rate of TC was further increased (0.204 min -1 ) but the removal rate remained basically unchanged, so a PMS dose of 0.5 mM was selected for subsequent studies.

[0070] Example 3

[0071] This example describes the effect of activating peroxymonosulfate with an iron-nitrogen doped porous carbon catalyst to degrade tetracycline wastewater. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operating steps of the reactor are as follows:

[0072] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0073] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0074] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to the specified temperature (600-900°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0075] Step 2: Addition of catalyst:

[0076] The degradation experiment was carried out in the reactor. First, the catalyst pot on the stirring paddle was moved out of the reaction chamber through the stirring device. Then 0.1 g L -1 Materials prepared in step 1. Then the catalyst can is mounted on the stirring paddle, and finally the catalyst can is pulled into the reaction chamber by the motor system.

[0077] Step 3: Run the reactor:

[0078] Transfer 0.1 g L into the catalyst tank -1After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the treated water enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the treated water flows through the static reactor, 0.25mM and 1mM PMS are mixed with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. The reaction lasts for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0079] like Figure 3 As shown, when 0.05 g L -1 When FeN doped porous carbon, the degradation efficiency and reaction rate of TC were 71.0% and 0.128 min, respectively. -1 When the catalyst addition amount was increased to 0.1 g L -1 When the catalyst dosage was increased to 0.2 g L -1 The above results show that 0.1gL -1 The amount of catalyst used can provide a sufficient number of active sites.

[0080] Example 4

[0081] The wastewater to be treated in this example comes from a -1 and 20 mg L -1 The tetracycline wastewater of HA is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operation steps of the reactor are as follows:

[0082] This example describes the effect of activating peroxymonosulfate with an iron-nitrogen doped porous carbon catalyst to degrade tetracycline wastewater. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operating steps of the reactor are as follows:

[0083] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0084] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0085] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to a specified temperature (500-1000°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0086] Step 2: Addition of catalyst:

[0087] The degradation experiment was carried out in the reactor. First, the catalyst pot on the stirring paddle was moved out of the reaction chamber through the stirring device. Then 0.1 g L -1 Materials prepared in step 1. Then the catalyst can is mounted on the stirring paddle, and finally the catalyst can is pulled into the reaction chamber by the motor system.

[0088] Step 3: Run the reactor:

[0089] Transfer 0.1 g L into the catalyst tank -1After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the treated water enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the treated water flows through the static reactor, 0.5mM PMS is mixed with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. Stir and react for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0090] like Figure 4 The effect of natural organic matter (NOM) represented by HA on TC degradation was investigated. -1 and 20 mg L -1 After HA, the removal rate of TC decreased to 74.7% (0.133min -1 ) and 61.3% (0.105min -1 ). NOM is considered to be a scavenger of free radicals, which easily competes with TC for oxidation, leading to a decrease in degradation efficiency. However, considering that the actual concentration of HA in nature is much lower than the experimental concentration, its inhibitory effect on the Fe-N-doped porous carbon / PMS system is relatively limited.

[0091] Example 5

[0092] The wastewater to be treated in this embodiment comes from tap water in a certain district of Tianjin. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operation steps of the reactor are as follows:

[0093] This example describes the effect of activating peroxymonosulfate with an iron-nitrogen doped porous carbon catalyst to degrade tetracycline wastewater. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operating steps of the reactor are as follows:

[0094] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0095] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0096] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to the specified temperature (600-900°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0097] Step 2: Addition of catalyst:

[0098] The degradation experiment was carried out in the reactor. First, the catalyst pot on the stirring paddle was moved out of the reaction chamber through the stirring device. Then 0.1 g L -1 Materials prepared in step 1. Then the catalyst can is mounted on the stirring paddle, and finally the catalyst can is pulled into the reaction chamber by the motor system.

[0099] Step 3: Run the reactor:

[0100] Transfer 0.1 g L into the catalyst tank -1 After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the treated water enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the treated water flows through the static reactor, 0.5mM PMS is mixed with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. Stir and react for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0101] Example 6

[0102] The wastewater to be treated in this embodiment comes from a lake in a certain district of Tianjin. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the operation steps of the reaction method and the reactor are as follows:

[0103] This example describes the effect of activating peroxymonosulfate with an iron-nitrogen doped porous carbon catalyst to degrade tetracycline wastewater. The water body is treated according to the technical scheme of the present invention. To ensure a good treatment effect, the reaction method and the operating steps of the reactor are as follows:

[0104] Step 1: Preparation of iron-nitrogen doped porous carbon:

[0105] First, a certain mass (M = 0.01, 0.02, 0.06 and 0.1g) of FeCl2·4H2O was dissolved in 1-100mL deionized water, and then 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 was added and stirred continuously at room temperature for 30min. Then 0.2g of CS powder was evenly dispersed in the above solution and 2% volume ratio of acetic acid was added to fully dissolve it to form a uniform viscous solution. Under continuous stirring, 1M NaOH solution was slowly added dropwise to the above viscous solution until a hydrogel was completely formed. After the gelation process was completed, the hydrogel was repeatedly rinsed with deionized water until a neutral pH value was reached. Subsequently, the gel was placed in a -80℃ refrigerator and frozen overnight, and then a vacuum freeze dryer was used to remove all moisture.

[0106] Finally, the samples were placed in a tube furnace and heated at 5 °C min -1 The temperature was raised to the specified temperature (600-900°C) at a rate and maintained for calcination for 2h to obtain iron-nitrogen doped porous carbons.

[0107] Step 2: Addition of catalyst:

[0108] The degradation experiment was carried out in the reactor. First, the catalyst pot on the stirring paddle was moved out of the reaction chamber through the stirring device. Then 0.1 g L -1 Materials prepared in step 1. Then the catalyst can is mounted on the stirring paddle, and finally the catalyst can is pulled into the reaction chamber by the motor system.

[0109] Step 3: Run the reactor:

[0110] Transfer 0.1 g L into the catalyst tank -1After the materials are prepared in step 1, open the water inlet valve, close the water outlet valve, and the treated water enters the reaction chamber after passing through the grid 1, the water inlet pump 2 and the static mixer 3; when the treated water flows through the static reactor, 0.5mM PMS is mixed with the wastewater to be treated, and the water intake accounts for 70%-75% of the volume of the reaction chamber. At the same time, start the stirring device 6, control the stirring rate to 200-500rpm, the working time of the motor system is 3-5min, and the closing time is 5-7min, which are carried out alternately. The reaction time of this step is 0-20min. After the reaction chamber step 1 is completed, close all the gate valves and blowers on the reaction chamber water inlet system, and then start. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. Stir and react for 0-15min. The treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; the water inlet is stopped, the catalyst canister on the stirring device is taken out, the catalyst is replaced, and then it is reloaded into the reaction chamber, and the experiment is repeated to further treat tetracycline wastewater.

[0111] Figure 5 To further evaluate the application potential of Fe-N-doped porous carbon in actual water environments, the effects of different water qualities on TC degradation were investigated. The reaction rate of TC in lake water and tap water decreased slightly to 0.167 min. -1 and 0.157min -1 , proving that the iron-nitrogen doped porous carbon / PMS system has strong anti-interference ability in actual water environment.

[0112] like Figure 6 As shown in (A), three consecutive cyclic degradation experiments investigated the recycling performance of the iron-nitrogen doped porous carbon catalyst. The TC removal rate of the three cyclic tests gradually decreased to 90.7%, 81.5% and 71.2%, respectively. This may be caused by the coverage of the active sites on the surface of the material by pollutants during the catalytic process. Through pyrolysis regeneration at 800°C, the TC removal rate in the iron-nitrogen doped porous carbon / PMS system was increased to 85.8%, proving that the iron-nitrogen doped porous carbon has good cyclic stability. In addition, the leaching amount of Fe ions in the degradation system was determined by ICP-MS, as shown in Figure 5. Figure 6 (B) The Fe ion concentrations of Fe-N-doped porous carbon leached in the system after three cycles and pyrolysis were 0.049, 0.038, 0.034, and 0.022 mg L-1, respectively. -1 , which is significantly lower than the total iron concentration (10 mg L -1 ), further proving that the material has excellent stability.

[0113] The present invention is described in detail above. Those skilled in the art can implement the present invention by appropriately changing the conditions and routes without departing from the scope of the present invention. Although the embodiments of the present invention have been described in detail, the embodiments of the present invention are not limited to the embodiments given, and all similar changes, substitutions and modifications are considered to be within the scope of the technical protection of the present invention.

Claims

1. A method for treating tetracycline wastewater and a reactor, comprising the following steps: Step 1, catalyst preparation, Take a certain mass (M = 0.01-0.1g) of FeCl2·4H2O and dissolve it in 1-100mL deionized water, then add 1,10-phenanthroline with a mass ratio (Fe:Phen) of 1:2 and stir continuously at room temperature for 30 minutes, then evenly disperse 0.1-1g CS powder in the above solution and add 2% volume ratio of acidic solution to fully dissolve it to form a uniform viscous solution. Under continuous stirring, slowly add 1M NaOH solution to the above viscous solution until the hydrogel is completely formed. After the gelation process is completed, rinse the hydrogel repeatedly with deionized water until a neutral pH value is reached. Subsequently, place the gel in a -80℃ refrigerator and freeze overnight, and then use a vacuum freeze dryer to remove all moisture. Finally, place the above sample in a tubular furnace and condense it at 5℃min in an Ar atmosphere. -1 The temperature was raised to a specified temperature (500-1000°C) at a rate and maintained for calcination for 2h to obtain an iron-nitrogen doped porous carbon material. Step 2: Addition of catalyst: The degradation experiment was carried out in the reactor. First, the catalyst medicine can on the stirring paddle was moved out of the reaction chamber by the stirring device. Then 0.5-1g of the material prepared in step 1 was transferred into the catalyst medicine can on the stirring paddle. Then, the catalyst medicine can was installed on the stirring paddle, and finally, the catalyst medicine can was pulled into the reaction chamber by the motor system. Step 3: Reactor operation. Add the filter tank to the wastewater, turn on the agitator, and drive the filter tank in the reaction chamber driven by the power system. The reaction lasts for 15 minutes. After the reaction, open the drain to complete the tetracycline degradation treatment of the wastewater.

2. A method and reactor for treating tetracycline wastewater according to claim 1, characterized in that: In step 1, the mass of FeCl2·4H2O is 0-0.5g, the mass of 1,10-phenanthroline is 0-1g, the mass of chitosan (CS) is 0-0.5g, the volume fraction of acetic acid solution is 0-10%, the concentration of sodium hydroxide solution is 0-2M, and the capacity is 1-1000ml.

3. A method and reactor for treating tetracycline wastewater according to claim 1, characterized in that: The freeze drying in step 1 includes freezing in a -80°C refrigerator for 1-24 hours and drying in a vacuum freeze dryer at -40°C for 1-24 hours.

4. A method and reactor for treating tetracycline wastewater according to claim 1, characterized in that: The catalyst calcination temperature in step 1 is 500-1000℃, and the highest calcination temperature is maintained for 1-3h. The heating rate is set at 5-15℃·min. -1 , the inert gas is argon or nitrogen.

5. A method and reactor for treating tetracycline wastewater according to claim 1, characterized in that: The second step of water inlet reaction: transferring persulfate into the reaction chamber through the dosing device, placing the catalyst into the catalyst medicine tank, and then letting the water to be treated enter the reaction chamber; Turn on the agitator at a speed of 200-600rpm. After 15 minutes of reaction, turn on the water inlet and outlet systems at the same time, the treated water is discharged through the outlet, and the wastewater to be treated enters the reaction chamber through the inlet, and the operation is repeated; Stop the water supply, take out the catalyst medicine tank on the stirring device, replace the catalyst, and then reload it into the reaction chamber, repeat the experiment, and further treat the tetracycline wastewater.

6. A reactor used in the method according to any one of claims 1 to 9, characterized in that: The invention comprises a cylindrical reaction chamber, wherein a water inlet system (1), a water outlet system (2), a catalyst medicine tank (3), a stirring device (4), a motor system (5) and a medicine adding device (6) are sequentially arranged on a water inlet connecting pipeline of the reaction chamber, and a water outlet is arranged on a middle side wall of the reaction tank.

7. A method and reactor for treating tetracycline wastewater according to claim 1, characterized in that: Used to activate persulfate to degrade antibiotics and antibiotic residues in wastewater.

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