Antibiotic-polluted underground water remediation method based on Fe / Nv-PCN piezoelectric material

Abstract

The invention is applicable to the technical field of pollution abatement, and particularly relates to a Fe / Nv-PCN piezoelectric material-based antibiotic-polluted underground water remediation method, which comprises the following steps: putting a Fe / Nv-PCN piezoelectric material into antibiotic-polluted underground water, exciting the piezoelectric effect of the Fe / Nv-PCN piezoelectric material through ultrasonic activation and driving to generate free radicals, and activating the free radicals to generate free radicals; the antibiotic pollutants are degraded. The excellent piezoelectric property and catalytic activity of the Fe / Nv-PCN piezoelectric material are utilized, ultrasonic excitation is applied in the underground water environment, the piezoelectric effect of the excitation material drives in-situ degradation, dependence of chemical agents is reduced, the long-term effect is improved, free radicals are generated, and antibiotic pollutants are efficiently degraded; the remediation method provided by the invention has the advantages of high efficiency, long effectiveness, environmental friendliness, wide applicability, economical efficiency and the like, is suitable for remediation of underground water polluted by various antibiotics, and provides a green, economical and sustainable new path for underground water remediation.

Description

Technical Field

[0001] The present invention belongs to the technical field of pollution control, and particularly relates to a method for repairing antibiotic-polluted groundwater based on Fe / Nv-PCN piezoelectric material. Background Art

[0002] Antibiotic pollution is an important global environmental problem faced by the current groundwater environment, mainly originating from the production of the pharmaceutical industry and the use and discharge of antibiotic drugs. Antibiotics (such as sulfonamides and tetracyclines) enter groundwater through infiltration and surface runoff. Antibiotics have the characteristics of being difficult to degrade, bioaccumulative, and ecotoxic, which not only affect the quality of groundwater but also may pose a serious threat to human health through the food chain.

[0003] Currently, the methods for repairing antibiotic-polluted groundwater mainly include physical adsorption, chemical oxidation, and biodegradation, etc. However, the physical adsorption method has problems such as limited adsorption capacity, difficult regeneration of the adsorbent, and inability to completely remove pollutants; the chemical oxidation method usually requires the addition of a large amount of chemical reagents, with high costs and easy to cause secondary pollution; the biodegradation method has specific requirements for the properties of pollutants, that is, the pollutants can be biodegraded, and antibiotics have a sterilizing effect, making it difficult to degrade by the microbial method. CN116282481A provides a method for enhancing the degradation of sulfonamide antibiotics by periodate, and CN114084936B discloses a preparation method of a carbon material for degrading sulfonamide antibiotics based on the electro-Fenton reaction and its application in degrading sulfonamide antibiotics.

[0004] Although the existing methods for treating antibiotic pollution provided by the prior art have a high degradation efficiency, problems such as the complexity of their treatment processes and material preparation and secondary pollution make it difficult to apply them to in-situ groundwater remediation. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for repairing antibiotic-polluted groundwater based on Fe / Nv-PCN piezoelectric material, aiming to solve the problem that although the existing methods for treating antibiotic pollution provided by the prior art have a high degradation efficiency, problems such as the complexity of their treatment processes and material preparation and secondary pollution make it difficult to apply them to in-situ groundwater remediation.

[0006] The present invention is implemented as follows. A method for repairing antibiotic-polluted groundwater based on Fe / Nv-PCN piezoelectric material, the method comprising: Put the Fe / Nv-PCN piezoelectric material into the antibiotic-polluted groundwater, and activate and drive the piezoelectric effect of the Fe / Nv-PCN piezoelectric material through ultrasonic excitation to generate free radicals for degrading antibiotic pollutants.

[0007] Preferably, the Fe / Nv-PCN piezoelectric material is composed of nitrogen vacancy-doped polymer carbon nitride Nv-PCN and iron element Fe, where the mass fraction of the iron element is 10% to 30%.

[0008] Preferably, in the step of activating and driving the piezoelectric effect of the Fe / Nv-PCN piezoelectric material by ultrasonic excitation, the frequency of the ultrasonic wave is 10 Hz to 100 Hz.

[0009] Preferably, in the step of putting the Fe / Nv-PCN piezoelectric material into the groundwater polluted by antibiotics, the dosage of the Fe / Nv-PCN piezoelectric material is 0.1 g / L to 2 g / L.

[0010] Preferably, in the groundwater polluted by antibiotics, the content of antibiotics is 1 mg / L to 100 mg / L.

[0011] Preferably, the reaction time of the Fe / Nv-PCN piezoelectric material and the groundwater polluted by antibiotics is 5 min to 60 min.

[0012] Preferably, the types of antibiotics in the groundwater polluted by antibiotics include at least one of tetracycline, sulfonamides, quinolones, and β-lactam antibiotics.

[0013] The method for repairing groundwater polluted by antibiotics based on the Fe / Nv-PCN piezoelectric material provided by the present invention utilizes the excellent piezoelectric properties and catalytic activity of the Fe / Nv-PCN piezoelectric material. By applying ultrasonic excitation in the groundwater environment, the piezoelectric effect of the material is excited to drive in-situ degradation, reducing the dependence on chemical agents and enhancing the long-term effectiveness, generating free radicals and efficiently degrading antibiotic pollutants. Moreover, the repair method provided by the present invention has the advantages of high efficiency, long-term effectiveness, environmental friendliness, wide applicability, and economy, and is suitable for the repair of groundwater polluted by various antibiotics, providing a new green, economic, and sustainable path for groundwater repair; From the perspective of the process technology, the Fe / Nv-PCN piezoelectric material has good stability. During the long-term groundwater repair process, it can continuously and stably exert piezoelectric catalytic effects, without the need to frequently replace the material, realizing the long-term repair of groundwater and being suitable for large-scale applications. This method does not require the addition of extra chemical reagents, conforming to the concept of green environmental protection. Compared with traditional repair technologies, this method does not require external energy (such as light, electricity). The method proposed in this application is simple to operate, and only relies on external forces (such as ultrasonic waves, mechanical vibrations, etc.) to activate the piezoelectric effect of the material, avoiding secondary pollution and solving the problem that the materials or microorganisms in traditional technologies are easily affected by the environment, resulting in unstable repair effects; In terms of operation effect and cost: Traditional technologies have deficiencies such as low repair efficiency, high cost, and easy secondary pollution. The method of this application has a high degradation rate. This method is applicable to the removal of various antibiotics in the groundwater environment. For example, the degradation rate of common tetracycline-polluted groundwater can reach over 97%. Moreover, no additional chemical reagents need to be added. The raw materials are inexpensive, the preparation method is simple, the equipment structures such as ultrasonic excitation are simple, and the operation cost is low, meeting the invention purpose in terms of high efficiency, environmental friendliness, and low cost. It can be applied to fields such as groundwater remediation projects and contaminated site treatment; In terms of the action mechanism: When the Fe / Nv-PCN piezoelectric material is put into the groundwater containing antibiotic pollution, the material is stimulated by ultrasonic waves to generate the piezoelectric effect, and a piezoelectric field is generated on the surface. Under the action of the piezoelectric field, the separation of electrons and holes is driven, and electrons reduce O2 to generate superoxide radicals (·O2 - ), and holes oxidize H2O to generate hydroxyl radicals (·OH). The reactive oxygen species on the material surface synergistically degrade antibiotics. These reactive oxygen species can undergo oxidation-reduction reactions with the antibiotics in the groundwater, gradually degrading the antibiotic molecules into harmless small molecule substances. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is the degradation curve graph of tetracycline pollutants using no catalyst, using PCN, using Nv-PCN, using Fe / PCN, and using Fe / Nv-PCN piezoelectric catalysts; Figure 2 It is the degradation curve graph of the cyclic experiment of degrading tetracycline pollutants using the Fe / Nv-PCN piezoelectric material as a catalyst; Figure 3 It is the degradation curve graph of degrading tetracycline pollutants with different pH values using the Fe / Nv-PCN piezoelectric material as a catalyst; Figure 4 It is the schematic diagram of the results of the influence of common groundwater ions in groundwater on the degradation of antibiotics by the Fe / Nv-PCN piezoelectric material; Figure 5 It is the schematic diagram of the results of exploring the reactive species that affect the degradation of antibiotics by the Fe / Nv-PCN piezoelectric material; Figure 6 It is the schematic diagram of the results of exploring the influence of pH value on the degradation effect of the Fe / Nv-PCN piezoelectric material; Figure 7 It is the schematic diagram of the results of exploring the influence of pollutant concentration on the degradation effect of the Fe / Nv-PCN piezoelectric material. DETAILED DESCRIPTION OF THE INVENTION

[0015] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] Example 1

[0017] An embodiment of the present invention provides a method for repairing groundwater contaminated with antibiotics based on Fe / Nv-PCN piezoelectric material, and the method includes: Put the Fe / Nv-PCN piezoelectric material into the groundwater contaminated with antibiotics, and activate and drive the piezoelectric effect of the Fe / Nv-PCN piezoelectric material through ultrasonic excitation to generate free radicals and degrade the antibiotic pollutants.

[0018] In the embodiment of the present invention, iron and nitrogen vacancy co-doped polymer carbon nitride (Fe / Nv-PCN) is used as the piezoelectric catalytic material. The piezoelectric effect is triggered by ultrasonic mechanical vibration to generate a piezoelectric field to drive the generation of reactive oxygen species (ROS), and long-term degradation of antibiotic pollutants in groundwater is achieved without adding external chemical reagents. The method includes the following steps: putting the Fe / Nv-PCN piezoelectric material into the groundwater contaminated with antibiotics; activating and driving the piezoelectric effect of the Fe / Nv-PCN piezoelectric material through ultrasonic excitation to generate free radicals and degrade the antibiotic pollutants.

[0019] In an embodiment of the present invention, the Fe / Nv-PCN piezoelectric material is composed of nitrogen vacancy-doped polymer carbon nitride (Nv-PCN) and iron element (Fe), where the mass fraction of the iron element is 10% to 30%; the frequency of the ultrasonic wave is 10 Hz to 100 Hz; the dosage of the Fe / Nv-PCN piezoelectric material is 0.1 g / L to 2 g / L; the content of antibiotics in the groundwater is 1 mg / L to 100 mg / L; the reaction time is 5 min to 60 min. Antibiotics include but are not limited to tetracyclines, sulfonamides, quinolones and β-lactam antibiotics.

[0020] In the embodiment of the present invention, the steps for preparing the Fe / Nv-PCN piezoelectric material include: preparing nitrogen vacancy-doped polymer carbon nitride (Nv-PCN) by high-temperature calcination method, then introducing iron element into Nv-PCN by in-situ co-precipitation loading method, and finally making the iron element evenly distributed in the material by heat treatment.

[0021] During use, the Fe / Nv-PCN piezoelectric material is put into the groundwater aquifer contaminated with antibiotics at a dosage of 0.1 g / L to 2 g / L for degradation treatment. 2-3 mL of solution can be taken every 30 s to 1 min, and its absorbance can be measured with an ultraviolet-visible absorption spectrometer to detect the treatment effect.

[0022] The Fe / Nv-PCN piezoelectric material prepared by the present invention using the high-temperature calcination method and the in-situ coprecipitation loading method, combined with the ultrasonic excitation method, thus prepares a porous composite piezoelectric catalytic system with excellent piezoelectric properties. The improvement lies in loading iron on C3N4 containing nitrogen vacancies, and at the same time creating a piezoelectric degradation antibiotic system driven by ultrasound through ultrasonic excitation under specific conditions.

[0023] To verify the degradation effect of the present invention, it is illustrated by multiple groups of experiments: To verify the degradation rate, the following steps are carried out in this example: Example 2

[0024] Step 1): In a certain tetracycline-polluted site, a groundwater sampling well is built to collect polluted groundwater, and the tetracycline concentration is measured to be 10.6 mg / L. Step 2): Add 20 mg of catalyst to a 100 mL reactor, which contains 30 mL of tetracycline aqueous solution (10 ppm). Step 3): Before ultrasonic irradiation, the solution is placed in a static environment for 30 min to achieve adsorption-desorption equilibrium. Step 4): Then turn on the ultrasound, use circulating water to ensure that the temperature in the ultrasonic machine is constant at room temperature, start the reaction, and the ultrasonic time is 60 minutes.

[0025] Step 5): Take 1 mL of solution as a sample at regular intervals, and separate the catalyst from the solution with a 0.22 μm microporous filter membrane. Step 6): Use an ultraviolet spectrophotometer to measure the absorbance at 356 nm, and then convert the corresponding tetracycline concentration and degradation rate to detect the change of ciprofloxacin concentration with time. Each group of experiments is set with 3 parallel samples.

[0026] The whole experiment is carried out at room temperature (26 °C), and the room temperature is represented by 26 °C in the attached drawings.

[0027] Example 3

[0028] On the basis of Example 2, according to the experimental process of piezoelectric catalytic activity test, before the dark adsorption starts, different catalysts are used for comparison: no catalyst, PCN, Nv-PCN, Fe / PCN, Fe / Nv-PCN piezoelectric materials are used, that is, in Example 2, the catalyst in Step 2) is replaced with PCN, Nv-PCN, Fe / PCN, Fe / Nv-PCN piezoelectric materials and no catalyst is added; other steps remain unchanged, and the best catalyst is selected according to the experimental results. Samples are taken at regular intervals for ultraviolet spectrophotometer analysis, and the experimental results are as Figure 1As shown, it can be seen that the Fe / Nv-PCN piezoelectric material adopted in the present invention has higher catalytic efficiency and higher degradation rate. Dark adsorption refers to placing the reaction solution and the catalyst in a dark and quiet place before the ultrasonic piezoelectric reaction and allowing them to stand still to achieve adsorption equilibrium.

[0029] Example 4

[0030] To verify the stability of the Fe / Nv-PCN piezoelectric material, a cyclic experiment was carried out for verification: On the basis of Example 2, according to the process of the piezoelectric catalytic activity test experiment, five groups of experiments were carried out in parallel. One group of experimental samples was taken for liquid-phase testing to obtain the first set of performance experimental data. The catalysts of the above five groups of experiments were recovered, and four groups of experiments were carried out in parallel again at the same time. One group of experimental samples was taken for liquid-phase testing to obtain the second set of performance experimental data. And so on, five cyclic experiments were completed. That is, according to Example 2, the Fe / Nv-PCN piezoelectric material was used as the catalyst, and other steps remained unchanged for the experiment. After the experiment was completed, the Fe / Nv-PCN piezoelectric material was recovered, and the recovered Fe / Nv-PCN piezoelectric material was used to repeat the experiment 4 times, and a total of five experimental results were obtained. During this period, the structure and performance changes of the Fe / Nv-PCN piezoelectric material were regularly detected. The experimental results are as Figure 2 shown. At the same time, the concentration of antibiotics in the groundwater after treatment was continuously monitored. The results showed that during the entire operation period, the crystal structure and piezoelectric properties of the Fe / Nv-PCN piezoelectric material remained stable, and the degradation rate of antibiotics in the groundwater always maintained at about 85+%, fully verifying the long-term stability of the present invention.

[0031] Example 5

[0032] To further explore the influencing factors of the catalytic process, further experiments were carried out for exploration.

[0033] On the basis of Example 2, according to the process of the piezoelectric catalytic activity test experiment, with the Fe / Nv-PCN piezoelectric material as the catalyst, before the start of dark adsorption, the pH values were respectively adjusted to 1, 3, 5, 7, 9, and 11 to study the effect of the Fe / Nv-PCN piezoelectric material on the degradation of antibiotics, that is, before step 3) in Example 2, the pH values of the solution were respectively adjusted to 1, 3, 5, 7, 9, and 11, and 6 experiments were carried out, and other steps remained unchanged; during the experiment, samples were taken at regular intervals for ultraviolet spectrophotometer analysis. The experimental results are as Figure 3 shown; according to Figure 3 it can be seen that from the experiment of adjusting the pH, the pH range of use of this piezoelectric material is relatively wide.

[0034] Example 6

[0035] On the basis of Example 2, according to the experimental process of piezoelectric catalytic activity test, using the Fe / Nv-PCN piezoelectric material as the catalyst, before the dark adsorption starts, the concentrations of tetracycline are adjusted to 1 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm and 100 ppm respectively, that is, in step 2) of Example 2, the concentrations of the tetracycline aqueous solution are adjusted to 1 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm and 100 ppm respectively, and other steps remain unchanged, to study the effect of the Fe / Nv-PCN piezoelectric material on the degradation of antibiotics. Samples are taken at regular intervals for ultraviolet spectrophotometer analysis. The experimental results are as Figure 6 shown. It can be seen from Figure 6 that the degradation reaction is affected by the concentration of tetracycline, and the higher the concentration, the greater the impact.

[0036] Example 7

[0037] On the basis of Example 2, according to the experimental process of piezoelectric catalytic activity test, using the Fe / Nv-PCN piezoelectric material as the catalyst, before the dark adsorption starts, the dosages of the Fe / Nv-PCN piezoelectric material are adjusted to 5 mg, 10 mg, 20 mg and 30 mg respectively, that is, in step 2) of Example 2, the dosages of the catalyst are adjusted to 5 mg, 10 mg, 20 mg and 30 mg respectively, and the experiment is carried out with other steps remaining unchanged; samples are taken at regular intervals for ultraviolet spectrophotometer analysis. The experimental results are as Figure 7 shown. It can be seen from Figure 7 that the more the dosage of the Fe / Nv-PCN piezoelectric material, the better the degradation effect.

[0038] Example 8

[0039] On the basis of Example 2, according to the experimental process of piezoelectric catalytic activity test, using the Fe / Nv-PCN piezoelectric material as the catalyst, before the dark adsorption starts, in each experiment, before step 3), common groundwater ions (ion concentration is 10 mmol L -1 ) are added to the solution, including Na + , K + , Ca + , Mg + , Cl + , NO3 - , CO3 2- , HCO3 - and SO4 2- . One common groundwater ion is added each time, and multiple experiments are carried out to explore the effect on the degradation of antibiotics by the Fe / Nv-PCN piezoelectric material. Samples are taken at regular intervals for ultraviolet spectrophotometer analysis. The experimental results are as Figure 4 shown. It can be seen from Figure 4 that the above-mentioned ions have little effect on the degradation effect.

[0040] Example 9

[0041] On the basis of Example 2, according to the process of the piezoelectric catalysis activity test experiment, using the Fe / Nv-PCN piezoelectric material as the catalyst, before the dark adsorption starts, explore the active species that affect the degradation of antibiotics by the Fe / Nv-PCN piezoelectric material (the concentration of the radical scavenger is 2 mmol L -1 ), that is, before step 3) of Example 2, add different scavengers isopropanol (IPA), ascorbic acid (AA), furfuryl alcohol (FA), disodium ethylenediaminetetraacetate (EDTA-2Na) and potassium persulfate (K2S2O8) each time, and conduct the radical scavenging experiment in the piezoelectric catalysis reaction. Samples are taken at regular intervals for ultraviolet spectrophotometer analysis. The experimental results are as Figure 5 shown. It can be seen from Figure 5 that, compared with other scavengers, the addition of disodium ethylenediaminetetraacetate (EDTA-2Na), ascorbic acid (AA), and isopropanol (IPA) has a greater inhibitory effect on the degradation effect, indicating that holes, hydroxyl radicals and superoxide radicals are the main reactive species in the degradation process.

[0042] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for repairing antibiotic-polluted groundwater based on Fe / Nv-PCN piezoelectric material, characterized in that, The method includes: Put the Fe / Nv-PCN piezoelectric material into the groundwater polluted by antibiotics, and activate and drive the piezoelectric effect of the Fe / Nv-PCN piezoelectric material through ultrasonic excitation to generate free radicals for degrading antibiotic pollutants.

2. The method for repairing antibiotic-polluted groundwater based on the Fe / Nv-PCN piezoelectric material according to claim 1, wherein The Fe / Nv-PCN piezoelectric material is composed of nitrogen vacancy-doped polymeric carbon nitride Nv-PCN and iron element Fe, where the mass fraction of the iron element is 10% to 30%.

3. The method for repairing groundwater contaminated by antibiotics based on Fe / Nv-PCN piezoelectric material according to claim 1, characterized in that, In the step of activating and driving the piezoelectric effect of the Fe / Nv-PCN piezoelectric material through ultrasonic excitation, the frequency of the ultrasonic wave is 10 Hz to 100 Hz.

4. The method for repairing groundwater contaminated by antibiotics based on the Fe / Nv-PCN piezoelectric material according to claim 1, wherein In the step of putting the Fe / Nv-PCN piezoelectric material into the groundwater polluted by antibiotics, the dosage of the Fe / Nv-PCN piezoelectric material is 0.1 g / L to 2 g / L.

5. The method for repairing groundwater contaminated by antibiotics based on Fe / Nv-PCN piezoelectric material according to claim 1, characterized in that In the groundwater polluted by antibiotics, the content of antibiotics is 1 mg / L to 100 mg / L.

6. The method for repairing antibiotic-polluted groundwater based on Fe / Nv-PCN piezoelectric material according to claim 1, wherein The reaction time of the Fe / Nv-PCN piezoelectric material and the groundwater polluted by antibiotics is 5 min to 60 min.

7. The method for repairing antibiotic-polluted groundwater based on the Fe / Nv-PCN piezoelectric material according to claim 1, wherein The types of antibiotics in the groundwater polluted by antibiotics include at least one of tetracycline, sulfonamides, quinolones, and β-lactam antibiotics.

8. The method for repairing groundwater contaminated by antibiotics based on the Fe / Nv-PCN piezoelectric material according to claim 1, characterized in that In the step of putting the Fe / Nv-PCN piezoelectric material into the groundwater polluted by antibiotics, adjust the pH of the solution to 11.

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