A method for treating ciprofloxacin sewage

Abstract

The application provides a ciprofloxacin sewage treatment method, comprising the following steps: providing compound sewage containing ciprofloxacin and cadmium, adjusting the pH value of the compound sewage to 2-7, then adding Fe@C composite material, after a period of adsorption reaction, adding potassium persulfate, and continuing to react to remove ciprofloxacin and cadmium in the compound sewage. The method is simple in operation and mild in application conditions, can obviously improve the removal effect of ciprofloxacin in sewage, can simultaneously achieve good treatment effect on cadmium and ciprofloxacin compound pollution, can fill the blank in the related field, can solve the existing actual water body problem, and has practical application significance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment, and particularly relates to a ciprofloxacin sewage treatment method. BACKGROUND

[0002] For real water body environment, the combined pollution of antibiotics and heavy metals has attracted more and more attention in recent years due to its great threat to human health and ecological environment and environmental reality. The combined pollution of antibiotics and heavy metals has a wide range of sources, including livestock farming, chemical enterprises and pharmaceutical production enterprises. When wastewater containing pollutants is mixed together, various interactions occur. The mutual complexation between antibiotics and heavy metals not only makes the removal of the two more complex, but also produces stronger toxicity. In addition, due to the complexity of combined pollution, the toxicology caused by pollutants is difficult to determine, and research is less, further increasing the environmental risk.

[0003] Common pollutant removal methods mainly include adsorption, chemical precipitation and advanced oxidation. Among them, the advanced oxidation technology based on persulfate has been widely used for water pollution removal in recent years, but due to the stability of persulfate itself, a catalytically active substance needs to be provided to activate it. The commonly used catalysts include metal elements such as cobalt and copper and their series of compounds, but these catalysts will inevitably cause the dissolution of heavy metal ions, causing secondary pollution to the water body, and due to the agglomeration of metal particles and the ease of oxidation, the catalytic effect is reduced, limiting its application.

[0004] Biochar is a carbon-rich material produced by the thermal combustion of organic raw materials under limited oxygen. It has a wide range of sources, mostly agricultural and forestry industrial waste, and has rich carbon content, high cation exchange capacity, large specific surface area and stable structure, so it has a wide application in environmental fields such as water treatment. Studies have shown that the application of biochar as a carrier in the preparation of advanced oxidation catalysts can further reduce production costs and improve catalytic performance. As agricultural residues, the production of plant materials, lignin from pulp and paper industry and other industrial waste is large, only a small part is fully utilized, and because it has rich oxygen and adsorption functional groups, it is considered as an ideal biomass material for removing heavy metal pollution in water bodies. However, traditional biochar preparation usually uses equipment such as muffle furnaces for conventional pyrolysis, and this pyrolysis technology has high energy consumption and long preparation time, increasing production costs.

[0005] In addition to the shortcomings in material preparation, the existing research materials are mostly limited to adsorbing only heavy metals and organic matter, or only degrading organic matter in specific applications, and the treatment effect needs to be strengthened. There are few studies on the simultaneous adsorption of heavy metals and degradation of organic matter, and the related mechanism is not clear. SUMMARY

[0006] In view of the above technical problems, the present application provides a novel ciprofloxacin wastewater treatment method.

[0007] The present applicant has found through a large number of studies that when Fe@C composite material is used to treat ciprofloxacin wastewater, the treatment effect on ciprofloxacin can be significantly improved by adding cadmium-containing wastewater to the ciprofloxacin wastewater.

[0008] To achieve the above-mentioned purpose, the present application proposes the following solutions:

[0009] A ciprofloxacin wastewater treatment method, comprising:

[0010] A composite wastewater containing ciprofloxacin and cadmium is provided, the pH value of the composite wastewater is adjusted to 2-7, then Fe@C composite material is added, after a period of adsorption, potassium persulfate is added for a high-level oxidation process, and the reaction is continued to remove ciprofloxacin and cadmium in the composite wastewater.

[0011] As a preferred, the way of providing the composite wastewater containing ciprofloxacin and cadmium includes: mixing ciprofloxacin-containing wastewater and cadmium-containing wastewater; or providing wastewater containing both ciprofloxacin and cadmium.

[0012] As a preferred, the concentration of cadmium ions in the composite wastewater is 30-270 mg / L, and further preferably 50-250 mg / L, for example, it can be 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240 mg / L, etc., and the concentration of ciprofloxacin is 10-90 mg / L, and further preferably 30-90 mg / L, for example, it can be 40, 50, 60, 70, 80 mg / L, etc.

[0013] As a preferred, the dosage of the Fe@C composite material is 0.1-1 g / L, for example, it can be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 g / L.

[0014] As a preferred, the dosage of the potassium persulfate is 1-20 mmol / L, for example, it can be 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 mmol / L.

[0015] As a preferred, after the Fe@C composite material is added, the reaction time is 0.5-2 h; the reaction is performed with shaking or stirring; and the reaction temperature is 20-40℃.

[0016] As a preferred, after the potassium persulfate is added, the reaction time is 2-8 h, and the reaction is performed with shaking or stirring.

[0017] As preferred, the preparation method of the Fe@C composite material comprises:

[0018] (1) pyrolyzing alkali lignin to obtain biochar;

[0019] (2) first ball milling the reduced iron powder under a protective atmosphere, then adding the biochar and continuing to ball mill under the protective atmosphere, to obtain the Fe@C composite material.

[0020] As preferred, the pyrolysis temperature is 300-600℃, the pyrolysis is carried out under a non-oxidizing atmosphere (such as nitrogen, inert gas such as argon, etc.), the pyrolysis is microwave pyrolysis, and the time of the microwave pyrolysis is 15-120 min.

[0021] As preferred, in step (2), the mass ratio of the reduced iron powder to the biochar is 1:6-1:1, for example, it can be 1:5, 1:4, 1:3, 1:2, etc.

[0022] As preferred, the time of the first ball milling is 6-18 h, and the time of the second ball milling is 6-18 h.

[0023] The first ball milling and the second ball milling are carried out by a swing ball mill, the rotation speed of the ball milling is 1000-1500 r / min, the ball-to-material mass ratio is 30:1-50:1, and the diameter of the ball milling beads is 3-10 mm.

[0024] Optionally, the protective atmosphere is a nitrogen atmosphere or an inert atmosphere, for example, an argon atmosphere.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] 1. The treatment method of the present application is simple in operation and mild in application conditions, can not only significantly improve the removal effect of ciprofloxacin in wastewater, but also can simultaneously achieve good treatment effect on cadmium and ciprofloxacin composite pollution, can fill the gap in the related field, can solve the existing actual water body problem, and has practical application significance.

[0027] 2. The present application uses alkali lignin as raw material to prepare the adsorption material Fe@C composite material, realizes resource utilization of waste, has low raw material cost, is widely available, and the prepared composite material can improve the removal effect of cadmium.

[0028] 3. The present application clarifies the mechanism of the Fe@C composite material for simultaneously removing cadmium and ciprofloxacin, and provides ideas for subsequent research in the related field. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0030] Figure 1 is an X-ray diffraction pattern of the reduced iron powder in Example 1, wherein, Figure 1 (a) is an X-ray diffraction pattern of the reduced iron powder in Example 1; Figure 1 (b) is an X-ray diffraction pattern of the Fe@C composite material obtained in Example 1; Figure 1 (c) is an X-ray diffraction pattern of the ball-milled biochar BC obtained in Comparative Example 1.

[0031] Figure 2 is a scanning electron microscope image, wherein, Figure 2 (a) is a scanning electron microscope image of the reduced iron powder in Example 1; Figure 2 (b) is a scanning electron microscope image of the ball-milled biochar BC obtained in Comparative Example 1; Figure 2 (c) is a scanning electron microscope image of the Fe@C composite material obtained in Example 1.

[0032] Figure 3 is a removal rate of cadmium and ciprofloxacin by the Fe@C composite material obtained in Example 1 and the ball-milled biochar BC obtained in Comparative Example 1 in single cadmium pollution, single ciprofloxacin pollution and cadmium and ciprofloxacin composite pollution.

[0033] Figure 4 is a comparison chart of removal rates of cadmium and ciprofloxacin by the Fe@C composite material obtained in Example 1 in cadmium and ciprofloxacin composite pollution at different pH values, wherein, Figure 4 (a) is a comparison chart of removal rates of cadmium; Figure 4 (b) is a comparison chart of removal rates of ciprofloxacin.

[0034] Figure 5 is an X-ray diffraction pattern of the Fe@C composite material after completion of the experiment in Example 2.

[0035] Figure 6 is a scanning electron microscope image of the Fe@C composite material after completion of the experiment in Example 2.

[0036] Figure 7 is a comparison chart of removal rates of cadmium and ciprofloxacin by the Fe@C composite material obtained in Example 1 in cadmium and ciprofloxacin composite pollution at different cadmium concentrations, wherein, Figure 7 (a) is a comparison chart of removal rates of cadmium; Figure 7 (b) is a comparison chart of removal rates of ciprofloxacin.

[0037] Figure 8 UV absorption spectrum of cadmium and ciprofloxacin compound pollution with different cadmium concentrations in Example 1.

[0038] Figure 9 Ciprofloxacin removal rate after using a quencher in Example 5.

[0039] Figure 10 Electron paramagnetic resonance spectrum in Example 6. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present application is not limited to the following specific embodiments.

[0041] Example 1

[0042] The preparation method of the Fe@C composite material comprises the following steps:

[0043] 1) Pyrolyze the alkali lignin under an argon atmosphere at 400℃ for 30 minutes to obtain biochar;

[0044] 2) Put 1 g of reduced iron powder and 150 g of stainless steel beads (ball milling beads) into a stainless steel ball milling tank under an argon environment, then place the ball milling tank in a swing ball mill with a rotation speed of 1200 r / min, ball mill for 6 hours, then put 4 g of the biochar obtained in step 1) into the ball milling tank under an argon environment, continue to ball mill for 6 hours to obtain the Fe@C composite material, wherein the ball milling needs to be stopped for 30 minutes every 30 minutes of ball milling, and the ball milling beads in the ball milling tank are a mixture of ball milling beads with diameters of 3, 5, 7 and 10 mm, wherein the mass ratio of the ball milling beads with diameters of 3, 5, 7 and 10 mm is 2:6:4:3.

[0045] Comparative Example 1

[0046] The preparation method of the ball milled biochar comprises the following steps:

[0047] Put 5 g of the biochar obtained in step 1) of Example 1 and 150 g of stainless steel beads (ball milling beads) into a stainless steel ball milling tank under an argon environment, then place the ball milling tank in a swing ball mill with a rotation speed of 1200 r / min, ball mill for 6 hours to obtain the ball milled biochar BC, wherein the ball milling needs to be stopped for 30 minutes every 30 minutes of ball milling, and the ball milling beads in the ball milling tank are a mixture of ball milling beads with diameters of 3, 5, 7 and 10 mm, wherein the mass ratio of the ball milling beads with diameters of 3, 5, 7 and 10 mm is 2:6:4:3.

[0048] Figure 1X-ray diffraction patterns of the materials used in Example 1 and Comparative Example 1. Figure 1 (a) is the X-ray diffraction pattern of the reduced iron powder, the characteristic peaks of zero-valent iron can be observed at 2Θ = 44.7° and 65.0°, corresponding to the (1 1 0) and (2 0 0) crystal planes of zero-valent iron, respectively. Figure 1 (b) is the X-ray diffraction pattern of the ball-milled biochar BC, the main characteristic peaks at 2Θ = 30.1°, 34.2°, 35.2°, 38.0°, 41.5°, 44.5° and 46.5° indicate the existence of sodium carbonate in the ball-milled biochar, which can react with cadmium ions and thus help to remove cadmium in the complex pollution. Figure 1 (c) is the X-ray diffraction pattern of the Fe@C composite material, the characteristic peaks of zero-valent iron can be observed, in addition, weak characteristic peaks of sodium carbonate can also be observed, which is due to the fact that the characteristic peaks of zero-valent iron are too strong to obscure the characteristic peaks of sodium carbonate, indicating that the Fe@C composite material contains both zero-valent iron and sodium carbonate. It is worth noting that compared with the X-ray diffraction pattern of the iron powder, the characteristic peaks of zero-valent iron in the Fe@C composite material shift to the direction of decreasing angle, and the diffraction peaks become wider, indicating that heteroatoms are inserted into the crystal during ball milling, and also indicating that the zero-valent iron and the biochar are successfully compounded.

[0049] Figure 2 Scanning electron microscope images of the materials used in Example 1 and Comparative Example 1. Among them, Figure 2 (a) is the scanning electron microscope image of the iron powder, which shows that the iron powder is decomposed into micron-sized particles after ball milling, and particle agglomeration occurs due to the interaction between the particles. Figure 2 (b) is the scanning electron microscope image of the ball-milled biochar BC, which shows that the ball-milled biochar BC is broken into many irregular spherical materials of different sizes during ball milling, indicating that the original structure of the biochar is destroyed during ball milling, and the bright spots in the image may be due to the existence of sodium carbonate on the surface of the ball-milled biochar BC, which causes the accumulation of too many electrons on the surface without a sinking path, resulting in a local discharge effect; Figure 2 (c) is the scanning electron microscope image of the Fe@C composite material, it can be seen that the iron powder particles are covered by biochar, which slows down the oxidation rate of zero-valent iron to a certain extent, promotes the transfer of electrons in the reaction process, and improves the catalytic activity.

[0050] Example 2

[0051] Take 25 mg of Fe@C composite material prepared in Example 1, add it to 50 mL of a composite contaminated (BS) aqueous solution containing 150 mg / L of cadmium and 50 mg / L of ciprofloxacin, and place it in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Then, 5 mmol / L of potassium persulfate is added to the solution, and the same experimental conditions are continued to shake for 4 hours to perform an advanced oxidation degradation experiment. Among them, the content of cadmium in the solution is detected by inductively coupled plasma emission spectrometer, and the content of ciprofloxacin in the solution is detected by ultraviolet visible spectrophotometer, the initial pH of the solution is 4, and the temperature is 25°C.

[0052] Comparative Example 2

[0053] Take 25 mg of Fe@C composite material prepared in Example 1, add it to 50 mL of a single contaminated (SS) aqueous solution containing 150 mg / L of cadmium, and place it in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Then, 5 mmol / L of potassium persulfate is added to the solution, and the same experimental conditions are continued to shake for 4 hours to perform an advanced oxidation degradation experiment. Among them, the content of cadmium in the solution is detected by inductively coupled plasma emission spectrometer, and the initial pH of the solution is 4, and the temperature is 25°C.

[0054] Comparative Example 3

[0055] Take 25 mg of Fe@C composite material prepared in Example 1, add it to 50 mL of a single contaminated (SS) aqueous solution containing 50 mg / L of ciprofloxacin, and place it in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Then, 5 mmol / L of potassium persulfate is added to the solution, and the same experimental conditions are continued to shake for 4 hours to perform an advanced oxidation degradation experiment. Among them, the content of ciprofloxacin in the solution is detected by ultraviolet visible spectrophotometer, and the initial pH of the solution is 4, and the temperature is 25°C.

[0056] Comparative Example 4

[0057] Take 25 mg of ball-milled biochar BC prepared in Comparative Example 1, add it to 50 mL of a composite contaminated (BS) aqueous solution containing 150 mg / L of cadmium and 50 mg / L of ciprofloxacin, and place it in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Then, 5 mmol / L of potassium persulfate is added to the solution, and the same experimental conditions are continued to shake for 4 hours to perform an advanced oxidation degradation experiment. Among them, the content of cadmium in the solution is detected by inductively coupled plasma emission spectrometer, and the content of ciprofloxacin in the solution is detected by ultraviolet visible spectrophotometer, and the initial pH of the solution is 4, and the temperature is 25°C.

[0058] Comparative Example 5

[0059] 25 mg of the ball-milled biochar BC prepared in Comparative Example 1 was weighed and added to 50 mL of a single pollution (SS) aqueous solution containing 150 mg / L of cadmium, and placed in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Subsequently, 5 mmol / L of potassium persulfate was added to the solution to continue shaking under the same experimental conditions for 4 hours to perform an advanced oxidation degradation experiment. Among them, the content of cadmium in the solution was detected by an inductively coupled plasma emission spectrometer, the initial pH of the solution was 4, and the temperature was 25°C.

[0060] Comparative Example 6

[0061] 25 mg of the ball-milled biochar BC prepared in Comparative Example 1 was weighed and added to 50 mL of a single pollution (SS) aqueous solution containing 50 mg / L of ciprofloxacin, and placed in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Subsequently, 5 mmol / L of potassium persulfate was added to the solution to continue shaking under the same experimental conditions for 4 hours to perform an advanced oxidation degradation experiment. Among them, the content of ciprofloxacin in the solution was detected by an ultraviolet-visible spectrophotometer, the initial pH of the solution was 4, and the temperature was 25°C.

[0062] Figure 3 The removal rates of cadmium and ciprofloxacin in single cadmium pollution, single ciprofloxacin pollution and cadmium and ciprofloxacin composite pollution by the Fe@C composite material obtained in Example 1 and the ball-milled biochar BC obtained in Comparative Example 1 in the operations of Example 2 and Comparative Examples 2-6. As can be seen from the figure, for single pollution (SS), the removal rates of cadmium and ciprofloxacin by the Fe@C composite material were 98.78% and 40.77% respectively, and the removal rates of cadmium and ciprofloxacin by the ball-milled biochar BC were 99.52% and 42.17% respectively. For composite pollution (BS), the removal rates of cadmium and ciprofloxacin by the Fe@C composite material were 96.00% and 76.52% respectively, and the removal rates of cadmium and ciprofloxacin by the ball-milled biochar BC were 98.00% and 54.50% respectively. The results show that the removal effect of ciprofloxacin by the Fe@C composite material and the ball-milled biochar BC in composite pollution is better than that in single pollution, and the removal rates are increased by 31.88% and 12.33% respectively, and at the same time of improving the removal effect of ciprofloxacin, the removal of cadmium is hardly affected. In addition, the removal effect of ciprofloxacin by the Fe@C composite material in composite pollution is 18.15% higher than that by the ball-milled biochar BC, indicating that the Fe@C composite material has excellent removal performance for composite pollution.

[0063] Example 3

[0064] Take 25 mg of Fe@C composite material prepared in Example 1, add it to a 50 mL composite contaminated (BS) aqueous solution containing 150 mg / L cadmium and 50 mg / L ciprofloxacin at the same time, and place it in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform a static adsorption experiment. Then add 5 mmol / L potassium persulfate to the solution and continue to shake under the same experimental conditions for 4 hours to perform a advanced oxidation degradation experiment. Among them, the content of cadmium in the solution is detected by inductively coupled plasma emission spectrometer, and the content of ciprofloxacin in the solution is detected by ultraviolet visible spectrophotometer, the initial pH of the solution is set to 2, 3, 4, 5, 6, 7, and the temperature is 25°C.

[0065] Figure 4 The removal rates of cadmium and ciprofloxacin by the Fe@C composite material obtained in Example 1 under the operation of Example 3 under the combined pollution of cadmium and ciprofloxacin, wherein, Figure 4 (a) is the removal rate of cadmium; Figure 4 (b) is the removal rate of ciprofloxacin. As can be seen from the figure, as the initial pH of the solution increases, the removal rate of cadmium rises rapidly and then stabilizes, while the removal rate of ciprofloxacin first increases and then decreases, indicating that the removal rates of the two pollutants in the combined pollution are different due to the change of pH. When the initial pH of the solution is 4, the removal rate of ciprofloxacin is the highest, which is 76.52%, and at the same time, the removal rate of cadmium is 96.00%.

[0066] Figure 5 The X-ray diffraction pattern of the Fe@C composite material after the completion of Example 2 experiment. The main characteristic peaks are at 2θ = 23.5°, 30.3°, 36.4°, 43.8° and 49.9°, indicating that cadmium carbonate is produced in the Fe@C composite material after the experiment, which is due to the reaction of sodium carbonate contained in the Fe@C composite material with cadmium in the solution, and the precipitation adsorption occurs, thereby achieving the purpose of efficient removal of cadmium. Figure 6 The scanning electron microscope image of the Fe@C composite material after the completion of Example 2 experiment. As can be seen from the figure, the surface of the Fe@C composite material after the experiment is surrounded by a large number of cubic particles, and these particles are not only on the surface of the Fe@C composite material, but also scattered in other places, further indicating that the precipitation adsorption is the main mechanism for the removal of cadmium in the solution.

[0067] Example 4

[0068] Five 25 mg of Fe@C composite prepared in Example 1 were weighed and added into 50 mL of the composite polluted (BS) aqueous solution containing cadmium and 50 mg / L of ciprofloxacin at different concentrations of cadmium (50, 100, 150, 200 mg / L and 250 mg / L), respectively, and placed in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to conduct a static adsorption experiment. Subsequently, 5 mmol / L of potassium persulfate was added into the solution to continue to shake under the same experimental conditions for 4 hours to conduct a high-level oxidation degradation experiment. Among them, the content of cadmium in the solution was detected by an inductively coupled plasma emission spectrometer, and the ultraviolet absorption spectrum of the cadmium and ciprofloxacin composite polluted liquid at different concentrations of cadmium and the content of ciprofloxacin in the solution were detected by a ultraviolet visible spectrophotometer.

[0069] Figure 7 The removal rates of cadmium and ciprofloxacin by the Fe@C composite obtained in Example 1 in the cadmium and ciprofloxacin composite pollution at different concentrations of cadmium. Among them, Figure 7 (a) is the removal rate of cadmium. From Figure 7 It can be seen from (a) that when the concentration of cadmium is higher than 150 mg / L, the removal efficiency of cadmium is reduced due to the limited adsorption capacity of Fe@C, but it can still reach 329.57 mg / L. Figure 7 (b) is the removal rate of ciprofloxacin by the Fe@C composite obtained in Example 1 in the cadmium and ciprofloxacin composite pollution at different concentrations of cadmium. It can be found that when the concentration of cadmium is 150 mg / L, the removal rate of ciprofloxacin is the highest, which may be due to the formation of a complex between cadmium and ciprofloxacin.

[0070] In order to study the complexing effect between cadmium and ciprofloxacin, the ultraviolet spectrum scanning of the cadmium and ciprofloxacin composite polluted liquid at different concentrations of cadmium was conducted, and the results are shown in Figure 8 In the figure, there is an obvious charge transfer transition absorption peak near 215 nm. This result confirms the existence of the cadmium and ciprofloxacin complex, and combined with the foregoing data, it can be comprehensively analyzed that the formation of this complex leads to ciprofloxacin being more easily attacked by the active species generated by the Fe@C composite catalyzing potassium persulfate, thereby promoting the removal of ciprofloxacin.

[0071] Example 5

[0072] Take three times 25 mg of Fe@C composite material prepared in Example 1, and add them to three groups of 50 mL of composite contaminated (BS) aqueous solution containing 150 mg / L of cadmium and 50 mg / L of ciprofloxacin, respectively, and place them in a constant temperature shaking box to shake at a speed of 200 r / min for 1 hour to perform static adsorption experiments. Then, 1 mol / L of ethanol (EtOH), 1 mol / L of tert-butyl alcohol (IPA), and 5 mmol / L of p-benzoquinone (p-BQ) are added as quenching agents to the above three groups of solutions, and after being mixed uniformly, 5 mmol / L of potassium persulfate is added to each of the three groups of solutions to continue shaking under the same experimental conditions for 4 hours to perform advanced oxidation degradation experiments. Among them, the content of cadmium in the solution is detected by an inductively coupled plasma emission spectrometer, and the content of ciprofloxacin in the solution is detected by a UV-visible spectrophotometer, the initial pH of the solution is 4, and the temperature is 25°C.

[0073] Figure 9 The ciprofloxacin removal rate after using the quenching agent in Example 5. As can be seen from the figure, compared with the other several groups of experiments, after adding p-benzoquinone, the removal rate of ciprofloxacin has decreased significantly, from 72.65% to 58.26%, indicating that under the action of the Fe@C composite material, the main active free radicals generated are superoxide free radicals (O2 ·- ).

[0074] Example 6

[0075] Take the solutions added with potassium persulfate at the 2nd, 5th, and 20th minutes in Example 5, respectively, and add them to a methanol solution with a 2,6-dimethylpyridine N-oxide (DMPO) concentration of 100 mmol / L to perform electron paramagnetic resonance spectrum tests.

[0076] Figure 10 The electron paramagnetic resonance spectrum in Example 6. As can be seen from the figure, no superoxide free radicals are generated in the solutions added with potassium persulfate at the 2nd and 5th minutes, but obvious superoxide free radical signals are detected at the 20th minute, further indicating that superoxide free radicals play a major role in the degradation of ciprofloxacin.

[0077] The upper and lower limits and interval values of the process parameters listed in the present application can all achieve the present application, and examples are not listed here.

[0078] The above only describes preferred embodiments of the present application and is not used to limit the scope of the rights of the present application. It should be noted that any simple modification, modification, or equivalent replacement that does not deviate from the core of the present application and can be achieved by a person skilled in the art without creative labor falls within the protection scope of the present application.

Claims

1. A method for treating ciprofloxacin wastewater, characterized by, The application relates to a method for removing ciprofloxacin and cadmium from composite sewage. The method comprises the following steps: providing composite sewage containing ciprofloxacin and cadmium, adjusting the pH value of the composite sewage to 2-7, adding Fe@C composite material, adding potassium persulfate after a period of adsorption reaction, and continuing to react to remove ciprofloxacin and cadmium in the composite sewage; the concentration of cadmium ions in the composite sewage is 30-270 mg / L, and the concentration of ciprofloxacin is 10-90 mg / L.

2. The method for treating ciprofloxacin sewage according to claim 1, wherein The method for providing the composite sewage containing ciprofloxacin and cadmium comprises the following steps: mixing sewage containing ciprofloxacin and sewage containing cadmium; or providing sewage containing both ciprofloxacin and cadmium.

3. The method for treating ciprofloxacin sewage according to claim 1, wherein The adding amount of the Fe@C composite material is 0.1-1 g / L. The adding amount of the potassium persulfate is 1-20 mmol / L.

4. The method for treating ciprofloxacin sewage according to claim 1, wherein After the Fe@C composite material is added, the adsorption reaction time is 0.5-2 h, and the adsorption reaction is carried out by oscillation or stirring; the adsorption reaction temperature is 20-40 DEG C.

5. The method for treating ciprofloxacin wastewater according to any one of claims 1 to 4, characterized by, After the potassium persulfate is added, the reaction time is 2-8 h; and the reaction is carried out by oscillation or stirring.

6. The method for treating ciprofloxacin sewage according to claim 1, wherein The preparation method of the Fe@C composite material comprises the following steps: (1) pyrolyzing alkali lignin to obtain biochar; (2) first ball milling of reduced iron powder under a protective atmosphere, then adding the biochar, and continuing to carry out second ball milling under the protective atmosphere to obtain the Fe@C composite material.

7. The method for treating ciprofloxacin sewage according to claim 6, wherein The pyrolysis temperature is 300-600 DEG C, and the pyrolysis is carried out under a non-oxidizing atmosphere; the pyrolysis is microwave pyrolysis, and the microwave pyrolysis time is 15-120 min.

8. The method for treating ciprofloxacin sewage according to claim 6, wherein In step (2), the mass ratio of the reduced iron powder to the biochar is 1:6-1:

1.

9. The method for treating ciprofloxacin sewage according to claim 6, wherein The first ball milling time is 6-18 h, and the second ball milling time is 6-18 h. The first ball milling and the second ball milling are carried out by a swing ball mill; the ball milling speed is 1000-1500 r / min; the ball-to-material mass ratio is 30:1-50:1; and the diameter of ball milling beads is 3-10 mm.

Images