Preparation method and application of composite piezoelectric catalytic material NaNbO3-BiFeO3 for rapidly degrading antibiotics

Abstract

The invention relates to a preparation method and application of a composite piezoelectric catalytic material NaNbO3-coated BiFeO3 for rapidly degrading antibiotics, NaNbO3 is flaky crystal grains with [001] crystallographic orientation prepared by a two-step molten salt method, and BiFeO3 is micro-nano particles prepared by a coprecipitation method. Composite micro-nano BiFeO3 powder and [001] oriented NaNbO3 flaky grains form a heterojunction, conversion of mechanical energy and electric energy of the material is achieved under the ultrasonic vibration condition, inductive charges are generated on the surface of the material, and photon-generated carriers move reversely under driving of a built-in electric field. According to the invention, the piezoelectric catalytic degradation capability of the BiFeO3 and NaNbO3 composite piezoelectric catalytic materials with different proportions on four antibiotics, namely oxytetracycline, levofloxacin, carbamazepine and paracetamol in different time periods is researched. When the mass ratio of the BiFeO3 to the NaNbO3 composite material is 1: 3, the oxytetracycline degradation rate within 30 min can reach 78.2%, the oxytetracycline degradation rate within 120 min can reach 91.8%, and the piezoelectric electro-catalysis characteristic is rapid and efficient. The method disclosed by the invention has important significance in developing a high-efficiency piezoelectric catalyst for degrading antibiotics.

Description

Technical Field

[0001] The present invention belongs to the field of piezoelectric catalysis and its application, relates to the technical field of a composite piezoelectric catalytic material, and more specifically to the technical field of a composite piezoelectric catalytic material for rapidly degrading antibiotics. Background Art

[0002] Since the beginning of the 21st century, energy scarcity and environmental pollution have become increasingly severe, forcing people to urgently seek innovative technologies to address these two major challenges. In recent years, the widespread use of drugs in the diagnosis and treatment of human diseases, as well as the popularity of personal care products, has led to serious drug contamination in the aquatic environment. Faced with the escalating water crisis, the scientific, rational, and efficient treatment of wastewater and its potential for resource utilization has become a key research topic in the fields of environmental pollution control and comprehensive energy utilization.

[0003] Piezocatalysis is an emerging research field that has attracted widespread interest in recent years. It involves directly converting mechanical energy into chemical energy through the piezoelectric effect of piezoelectric materials, enabling catalytic reactions such as water splitting and organic pollutant degradation. Piezocatalysis has the remarkable ability to improve the separation and migration of photoelectrons and holes without relying on external electrical or light energy input, thus showing great potential in areas such as environmental remediation and energy conversion.

[0004] NaNbO3, a typical perovskite piezoelectric material, has a valence band top and conduction band bottom composed of the 2p orbitals of O and the 3d orbitals of Nb, respectively, corresponding to a band gap of 3.4 eV. BiFeO3 is a multiferroic perovskite piezoelectric material with a corresponding band gap of approximately 2.2 eV. Current research on BiFeO3 and NaNbO3 heterojunction composite piezoelectric catalytic materials focuses on preparing micro- and nanostructured powders of varying morphologies using solid-state reaction, sol-gel, and hydrothermal methods. By manipulating the composition ratio of BiFeO3 and NaNbO3, preparation conditions, and doping elements, the piezoelectric properties of the composites, including piezoelectric constant, electromechanical coupling coefficient, and dielectric loss, are optimized. Charge separation, migration, and reaction processes under mechanical stress are studied to enhance piezoelectric catalytic efficiency. Although powders prepared using these methods exhibit acceptable degradation efficiency, their isotropic properties prevent them from fully exploiting the potential for surface induced charge generation, resulting in suboptimal piezoelectric catalytic degradation efficiency. Research on the application of piezoelectric catalysis has mostly focused on the piezoelectric photodegradation of organic dyes such as rhodamine B, methylene blue, and methyl orange. However, relatively few studies have examined the degradation of antibiotics, which are commonly found in wastewater, and this has certain limitations.

[0005] The preparation of oriented lamellar grains is an effective means to effectively improve the polarity of materials and increase the generation of induced charges on the surface of the materials. This method has been widely used to prepare textured ceramics to significantly improve the piezoelectric properties of ceramics, but has been less reported in the field of piezoelectric catalysis. Crystallographically oriented powder particles generally have better polarization properties, and ordered grain orientation can enhance the dipole arrangement inside the material, thereby improving the polarization efficiency. Crystallographically oriented powder particles have specific crystal planes exposed, and these crystal planes are more sensitive to external stress or strain, making it easier to generate surface induced charges. Ordered grain orientation can reduce the obstacles to charge migration within the crystal, thereby improving the charge migration efficiency. Ordered grain orientation helps to improve the response speed and sensitivity of piezoelectric materials, thereby improving the efficiency of piezoelectric catalysis. Summary of the Invention

[0006] The existing research on the application of piezoelectric catalysis in the existing technology has mostly focused on the piezoelectric photodegradation of organic dyes such as rhodamine B, methylene blue, and methyl orange. There is relatively little research on the degradation of antibiotics, which are detected in large quantities in wastewater. This has led to certain technical limitations. The present invention aims to provide a preparation method and application of a composite piezoelectric catalytic material NaNbO3@BiFeO3 for the rapid degradation of antibiotics. By forming a heterojunction between composite micro-nano BiFeO3 powder and

[001] -oriented NaNbO3 flake grains, the material achieves mechanical energy and electrical energy conversion under ultrasonic vibration conditions, generates induced charges on the material surface, and photogenerated carriers move in the opposite direction under the drive of the built-in electric field. The present invention studies the piezoelectric catalytic degradation ability of composite piezoelectric catalytic materials of BiFeO3 and NaNbO3 with different ratios over different time periods for four antibiotics: oxytetracycline, levofloxacin, carbamazepine, and paracetamol. The present invention is of great significance for the development of efficient piezoelectric catalysts for the degradation of antibiotics.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] The purpose of the present invention is to provide a composite piezoelectric catalytic material for rapid degradation of antibiotics. The composite piezoelectric catalytic material is prepared from NaNbO3 and BiFeO3. The NaNbO3 is a

[001] crystallographically oriented flaky grain prepared by a two-step molten salt method, and the BiFeO3 is a micro-nano particle prepared by a co-precipitation method.

[0009] Furthermore, the present application also provides a method for preparing a composite piezoelectric catalytic material for rapid degradation of antibiotics, which is prepared by the following steps:

[0010] (1) Select Bi(NO3)3.5H2O and Fe(NO3)3.9H2O with a purity greater than 99% as raw materials for micro-nano BiFeO3 powder; weigh the materials according to the stoichiometric ratio and stir them in a beaker for more than 5 hours; slowly add 1 mol / L NaOH solution to the above solution to precipitate a solid precipitate under alkaline conditions; let the above mixture stand for 24-48 hours, wash with distilled water, filter it until it is neutral, and dry it; place the dried sample in a high-temperature furnace for heat treatment at a temperature set at 500-550°C to obtain BiFeO3 micro-nano particles.

[0011] (2) Select Bi2O3, Na2CO3, Nb2O5, and NaCl with a purity greater than 99% as raw materials for

[001] crystallographically oriented NaNbO3 flake grains; weigh Bi2O3, Na2CO3, and Nb2O5 according to the stoichiometric ratio, add NaCl of the same mass as the mixture, use anhydrous ethanol as the ball milling medium, ball mill for 12 hours and dry, then place the mixture in a high-temperature furnace for insulation; after the reaction is complete, wash with deionized water to remove the sodium salt, and obtain Bi 2.5 Na 3.5 Nb5O 18 (BNN) precursor; the BNN precursor and Na2CO3 powder were mixed in a mass ratio of 6:1, and an equal mass of NaCl was added. Anhydrous ethanol was used as the ball milling medium. After ball milling for 12 hours and drying, the mixture was placed in a high-temperature furnace at 1100°C and kept warm for 3 hours. The sintered product was washed with nitric acid and deionized water, respectively, to obtain

[001] -oriented NaNbO3 flake grains.

[0012] (3) BiFeO3 micro-nanoparticles and

[001] -oriented NaNbO3 flake grains were weighed in proportion, 20-100 mL of anhydrous ethanol was added, and after ultrasonication for 1 h, the mixture was stirred on a magnetic stirrer for 12-48 h. After drying, the NaNbO3@BiFeO3 composite piezoelectric catalytic material was obtained.

[0013] Preferably, in step (1), the BiFeO3 micro-nanoparticles are prepared by chemical co-precipitation, and the pH value required for the co-precipitation is 9-13.

[0014] Preferably, the

[001] -oriented NaNbO3 flake grains in step (2) are prepared by a two-step molten salt method, the molten salt is NaCl with the same mass as the mixture powder, the precursor is BNN, the preparation temperature is 1100°C and the temperature is maintained for 3 hours, and the product needs to be acid-washed and water-washed.

[0015] Preferably, in the step (3), the BiFeO3 micro-nano particles and

[001] -oriented NaNbO3 flake grains are added with anhydrous ethanol and ultrasonically treated for 1 hour and then stirred for 12-48 hours.

[0016] The mass ratio of the BiFeO3 micro-nano powder to the

[001] oriented NaNbO3 flake grains in step (3) is (0.25-3):3.

[0017] Furthermore, the present application provides the use of the above-mentioned composite piezoelectric catalytic material in the efficient and rapid degradation of antibiotics in wastewater.

[0018] Preferably, the antibiotics include any one or more of oxytetracycline, levofloxacin, carbamazepine, and paracetamol.

[0019] Through the above technical solutions, this application achieves the following technical effects:

[0020] (1) The composite piezoelectric catalytic material prepared by the present invention has a rapid and efficient catalytic activity for antibiotics. Under ultrasonic vibration conditions, oxytetracycline can be degraded by 78.2% in 30 minutes and by 91.8% in 120 minutes.

[0021] (2) The composite piezoelectric catalytic material prepared by the present invention utilizes

[001] -oriented NaNbO3 flake grains as a substrate, utilizing their anisotropy to enhance the dipole arrangement within the material.

[001] -oriented NaNbO3 flake grains are more likely to generate surface induced charges, reducing obstacles to charge migration within the crystal, thereby improving charge migration efficiency. The ordered grain orientation helps to increase the response speed and sensitivity of the piezoelectric material, thereby improving the piezoelectric catalytic efficiency.

[0022] (3) The composite piezoelectric catalytic material prepared by the present invention is non-toxic and harmless, easy to prepare, has high visible light utilization efficiency and good stability, and can be recycled and reused. It not only avoids secondary pollution in the environment but also helps reduce the overall cost of treating antibiotics, and has broad application prospects in the field of antibiotic treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Shown are SEM images of BiFeO3 micro-nano powders,

[001] -oriented NaNbO3 flake grains, and NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Examples 1, 2, and 3;

[0024] Figure 2 Shown are the XRD spectra of BiFeO3 micro-nano powder,

[001] oriented NaNbO3 flake grains, and NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Example 1, Example 2, and Example 3.

[0025] Figure 3The figure shows the degradation efficiency of the antibiotic oxytetracycline by the NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Examples 1, 2, 3, and 4. The horizontal axis represents the piezoelectric photocatalytic time, and the vertical axis represents the degradation efficiency, the same below.

[0026] Figure a shows the change in absorbance at different wavelengths, and Figure b shows the change in concentration at different treatment times. The following figures are the same.

[0027] Figure 4 Shown are the degradation efficiencies of the NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Examples 1, 2, 3, and 5 for the antibiotic carbamazepine.

[0028] Figure 5 Shown are the degradation efficiencies of the NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Examples 1, 2, 3, and 6 for the antibiotic levofloxacin.

[0029] Figure 6 Shown are the degradation efficiencies of the NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Examples 1, 2, 3, and 7 for the antibiotic paracetamol.

[0030] Figure 7 Shown are the degradation efficiencies of the NaNbO3@BiFeO3 piezoelectric catalytic materials prepared in Examples 4, 5, 6, and 7 for the antibiotics oxytetracycline, levofloxacin, carbamazepine, and paracetamol. DETAILED DESCRIPTION

[0031] The technical solutions of the present invention are described clearly and completely below with reference to the embodiments. It is obvious that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0032] Unless otherwise specified in the following embodiments, the technical means used are conventional means well known to those skilled in the art.

[0033] Example 1: Preparation method of NaNbO3 flake grains

[0034] The present application provides a method for preparing NaNbO3 flake grains, namely a method for preparing

[001] -oriented NaNbO3 flake grains, the specific steps of which are as follows:

[0035] (1) Bi2O3, Na2CO3, Nb2O5, and NaCl with a purity greater than 99% are selected as raw materials for

[001] crystallographically oriented NaNbO3 flake grains;

[0036] (2) Bi2O3, Na2CO3, and Nb2O5 were weighed according to the stoichiometric ratio, and NaCl of the same mass as the mixture was added. Anhydrous ethanol was used as the ball milling medium. After ball milling for 12 h and drying, the mixture was placed in a high-temperature furnace at 1100°C for 3 h.

[0037] (3) After the reaction is complete, the sodium salt is removed by washing with deionized water to obtain Bi 2.5 Na 3.5 Nb5O 18 (BNN) precursor;

[0038] (4) BNN precursor and Na2CO3 powder were mixed in a mass ratio of 6:1, and an equal mass of NaCl was added. Anhydrous ethanol was used as the ball milling medium. After ball milling for 12 h and drying, the mixture was placed in a high-temperature furnace at 1100 °C for 3 h.

[0039] (5) The sintered product was washed with nitric acid and deionized water respectively to obtain

[001] oriented NaNbO3 flake grains.

[0040] In this embodiment, the morphology of

[001] oriented NaNbO3 flake grains was measured, as shown in FIG. Figure 1 As shown in the figure, it can be clearly observed that NaNbO3 has a relatively uniform and well-dispersed flake morphology, and the flake grain size is about 17.23μm in width, about 19.12μm in length, and about 1.47μm in thickness. Figure 2 This is the XRD spectrum of

[001] oriented NaNbO3 flake grains. The sample has a single perovskite phase structure.

[0041] Example 2: Preparation method of BiFeO3 micro-nano powder

[0042] The present invention provides a method for preparing BiFeO3 micro-nano powder, the specific steps of which are as follows:

[0043] (1) Selecting Bi(NO3)3.5H2O and Fe(NO3)3.9H2O with a purity greater than 99% as raw materials for micro-nano BiFeO3 powder;

[0044] (2) Weigh the materials according to the stoichiometric ratio and stir them in a beaker for more than 5 hours; slowly add 1 mol / L NaOH solution to the above solution to control the pH value of the mixture between 9-13;

[0045] (3) Precipitate a solid precipitate; let the mixture stand for 24-48 hours, wash with distilled water, filter until neutral, and dry;

[0046] (4) The dried sample is placed in a high temperature furnace for heat treatment at a temperature of 500-550°C to obtain BiFeO3 micro-nano powder particles.

[0047] In this embodiment, the morphology of BiFeO3 micro-nano powder particles under different pH conditions was measured, such as Figure 1 As shown in the figure, it can be clearly observed that with the gradual increase of pH value, the overall morphology of BiFeO3 micro-nano powder particles shows a transformation from flake to block, from agglomeration to dispersion and then to re-agglomeration, the pore size gradually decreases, and the particle size gradually decreases from 8μm to 2-3μm. When pH = 13, these fine particles will agglomerate again and accumulate into a nearly spherical body with a diameter of about 10μm. Figure 2 The XRD spectrum of BiFeO3 micro-nano powder particles shown in the figure shows that the sample has a single perovskite phase structure.

[0048] Example 3: Preparation method of composite piezoelectric catalytic material NaNbO3@BiFeO3 for rapid degradation of antibiotics

[0049] A preparation method of a composite piezoelectric catalytic material NaNbO3@BiFeO3 for rapid degradation of antibiotics, comprising the following steps:

[0050] (1) Weigh BiFeO3 micro-nanoparticles and

[001] -oriented NaNbO3 flakes in proportion and add 20-100 mL of anhydrous ethanol;

[0051] (2) ultrasonicating the mixture for 1 hour and then stirring on a magnetic stirrer for 12-48 hours;

[0052] (3) The mixture is dried to obtain a NaNbO3@BiFeO3 composite piezoelectric catalytic material;

[0053] In this embodiment, the morphology of the NaNbO3@BiFeO3 composite piezoelectric catalytic material was measured, such as Figure 1 As shown in the figure, it can be clearly observed that BiFeO3 is relatively evenly coated on the surface of NaNbO3 flake grains. Figure 2 The XRD spectrum of the NaNbO3@BiFeO3 composite piezoelectric catalytic material shown in the figure shows that the sample has a single perovskite phase structure.

[0054] Example 4: Application of a composite piezoelectric catalytic material NaNbO3@BiFeO3 for rapid degradation of antibiotics in the degradation of antibiotics.

[0055] Based on the descriptions in the above-mentioned embodiments 1 to 3, the application of the composite piezoelectric catalytic material NaNbO3@BiFeO3 for rapid degradation of antibiotics in the degradation of antibiotics is provided.

[0056] (1) Effect of NaNbO3@BiFeO3 composite piezoelectric catalytic material on the degradation rate of oxytetracycline under different illumination times

[0057] Degradation experiments were conducted using oxytetracycline as the target pollutant. 5 mg of oxytetracycline was weighed and mixed with deionized water to prepare an oxytetracycline solution with an initial concentration of 25.0 mg / L. Example 3 was then placed in the oxytetracycline solution and magnetically stirred in the dark for 30 minutes to achieve adsorption-desorption equilibrium. This suspension was then transferred to a reaction apparatus and activated by vibration under visible light irradiation at an ultrasonic frequency of 40 kHz and a power of 200-300 W to perform a piezoelectric photocatalytic reaction.

[0058] Figure 3 Table 1 shows the degradation rates of oxytetracycline by the NaNbO3@BiFeO3 composite piezoelectric catalytic material under different illumination times. The degradation of oxytetracycline by the single

[001] -oriented NaNbO3 flakes was not significant, with a degradation rate of only 14.7% after 120 minutes. The BiFeO3-modified NaNbO3@BiFeO3 composite piezoelectric catalytic material significantly improved the degradation rate, reaching 78.2% in just 30 minutes and 91.8% after 120 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0059] Table 1: Degradation rate of oxytetracycline by NaNbO3@BiFeO3 composite piezoelectric catalytic material under different illumination times

[0060] Photocatalytic piezoelectric time <![CDATA[NaNbO3]]> <![CDATA[BiFeO3@NaNbO3]]> 30min 0.63％ 78.20％ 60min 2.83％ 83.60％ 90 minutes 5.66％ 88.40％ 120 minutes 14.47％ 91.80％

[0061] (2) Effects of different ratios of BiFeO3 and NaNbO3 composite piezoelectric catalytic materials on the degradation rate of oxytetracycline

[0062] 0.005g, 0.075g, 0.010g, 1.1025g, 0.015g, and 0.020g of BiFeO3 micro-nano powder and 0.015mg of

[001] -oriented NaNbO3 flake crystals were weighed and dissolved in 50mL of anhydrous ethanol. After ultrasonic treatment for 1h, the mixture was magnetically stirred for 24h and then dried in an 85°C oven for 10h. The suspension was then magnetically stirred in the dark for 30min to allow the oxytetracycline solution and the powder particles to reach adsorption-desorption equilibrium. The suspension was then transferred to a reaction apparatus and vibrated under visible light irradiation at an ultrasonic frequency of 40kHz and a power of 200-300W to perform a piezoelectric photocatalytic reaction.

[0063] Figure 3Table 2 shows the degradation rates of oxytetracycline by composite piezoelectric catalytic materials with different BiFeO3 and NaNbO3 ratios. When the BiFeO3 micro-nano powder content is low, the degradation of oxytetracycline is poor, with a degradation rate of 1.5% after 30 minutes. As the BiFeO3 content increases, the degradation rate gradually exhibits a parabolic trend. When the BiFeO3 to NaNbO3 mass ratio is 2:3, the material achieves the best oxytetracycline degradation, reaching 91.8%. Furthermore, when the BiFeO3 to NaNbO3 mass ratio is 2:3, the degradation rate reaches 78.2% in just 30 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0064] Table 2: Degradation rate of oxytetracycline by composite piezoelectric catalytic materials with different ratios of NaNbO3@BiFeO3

[0065]

[0066] (3) Degradation rate of carbamazepine by NaNbO3@BiFeO3 composite piezoelectric catalytic material under different illumination times

[0067] Degradation experiments were conducted using carbamazepine as the target pollutant. 5 mg of carbamazepine was weighed and mixed with deionized water to prepare a carbamazepine solution with an initial concentration of 25.0 mg / L. Example 3 was then placed in the carbamazepine solution and magnetically stirred in the dark for 30 minutes to achieve adsorption-desorption equilibrium. This suspension was then transferred to a reaction apparatus and activated by vibration under visible light irradiation at an ultrasonic frequency of 40 kHz and a power of 200-300 W to perform a piezoelectric photocatalytic reaction.

[0068] Figure 4 Table 3 shows the degradation rates of carbamazepine (CBZ) by the NaNbO3@BiFeO3 composite piezoelectric catalytic material under different illumination times. The degradation of oxytetracycline by the single

[001] -oriented NaNbO3 flakes was poor, with a degradation rate of only 24.52% after 120 minutes. The BiFeO3-modified NaNbO3@BiFeO3 composite piezoelectric catalytic material significantly improved the degradation rate, reaching 68.64% in just 30 minutes and 77.04% after 120 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0069] Table 3: Degradation rate of carbamazepine by NaNbO3@BiFeO3 composite piezoelectric catalytic material under different light irradiation times

[0070] Photocatalytic piezoelectric time <![CDATA[NaNbO3]]> <![CDATA[NaNbO3@BiFeO3]]> 30min 0.04％ 68.64％ 60min 0.26％ 72.68％ 90 minutes 1.32％ 74.74％ 120 minutes 24.52％ 77.04％

[0071] (4) Effects of different ratios of BiFeO3 and NaNbO3 composite piezoelectric catalytic materials on the degradation rate of carbamazepine

[0072] 0.005g, 0.075g, 0.010g, 1.1025g, 0.015g, and 0.020g of BiFeO3 micro-nano powder and 0.015mg of

[001] -oriented NaNbO3 flakes were weighed, added to 50mL of anhydrous ethanol, and ultrasonically treated for 1 hour. The mixture was then magnetically stirred for 24 hours and dried in an 85°C oven for 10 hours. The suspension was then magnetically stirred for 30 minutes in the dark to allow the carbamazepine solution and powder particles to reach adsorption-desorption equilibrium. The suspension was then transferred to a reaction apparatus and activated by vibration under visible light irradiation at an ultrasonic frequency of 40kHz and a power of 200-300W to perform a piezoelectric photocatalytic reaction.

[0073] Figure 4 Table 4 shows the degradation rates of carbamazepine by the composite piezoelectric catalytic materials with different BiFeO3 and NaNbO3 ratios. When the BiFeO3 micro-nano powder content is low, the degradation of carbamazepine is poor, with a degradation rate of 1.5% after 30 minutes. With increasing BiFeO3 content, the degradation rate increases and then decreases. When the BiFeO3 to NaNbO3 mass ratio is 1:3, the material achieves the best degradation of carbamazepine, reaching 77.04%. Furthermore, when the BiFeO3 to NaNbO3 mass ratio is 1:3, the degradation rate reaches 68.64% in just 30 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0074] Table 4: Effects of different ratios of BiFeO3 and NaNbO3 composite piezoelectric catalytic materials on the degradation rate of carbamazepine

[0075]

[0076] (5) Degradation rate of levofloxacin by NaNbO3@BiFeO3 composite piezoelectric catalytic material

[0077] A degradation experiment was conducted using levofloxacin as the target pollutant. A levofloxacin solution with an initial concentration of 25.0 mg / L was prepared by weighing 5 mg of levofloxacin and adding it to deionized water. Example 3 was then placed in the levofloxacin solution and magnetically stirred for 30 minutes in the dark, allowing the levofloxacin solution and the powder particles to reach adsorption-desorption equilibrium. This suspension was then transferred to a reaction apparatus and activated by vibration under visible light irradiation at an ultrasonic frequency of 40 kHz and a power of 200-300 W to perform a piezoelectric photocatalytic reaction.

[0078] Figure 5Table 5 shows the degradation rates of levofloxacin by the NaNbO3@BiFeO3 composite piezoelectric catalytic material under different illumination times. Single

[001] -oriented NaNbO3 flakes showed poor levofloxacin degradation, with a degradation rate of only 18.64% after 120 minutes. The BiFeO3-modified NaNbO3@BiFeO3 composite piezoelectric catalytic material significantly improved the degradation rate, reaching 41.41% in just 60 minutes and 84.78% after 120 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0079] Table 5: Degradation rate of levofloxacin by NaNbO3@BiFeO3 composite piezoelectric catalytic material

[0080] Photocatalytic piezoelectric time <![CDATA[NaNbO3]]> <![CDATA[NaNbO3@BiFeO3]]> 30min 8.95％ 16.49％ 60min 11.32％ 41.41％ 90 minutes 15.98％ 67.24％ 120 minutes 18.60％ 84.78％

[0081] (6) Effect of different ratios of NaNbO3@BiFeO3 composite piezoelectric catalytic materials on the degradation rate of levofloxacin

[0082] 0.005g, 0.075g, 0.010g, 1.1025g, 0.015g, and 0.020g of BiFeO3 micro-nano powder and

[001] -oriented NaNbO3 flakes were weighed, added to 50mL of anhydrous ethanol, and sonicated for 1 hour. The mixture was then placed in a magnetic stirrer for 24 hours, dried in an 85°C oven for 10 hours, and then magnetically stirred for 30 minutes in the dark to allow the levofloxacin solution and powder particles to reach adsorption-desorption equilibrium. The suspension was then transferred to a reaction apparatus and activated by vibration under visible light irradiation at an ultrasonic frequency of 40kHz and a power of 200-300W to perform a piezoelectric photocatalytic reaction.

[0083] Figure 5 Table 6 shows the degradation rates of levofloxacin using NaNbO3@BiFeO3 composite piezoelectric catalytic materials with different ratios. When the BiFeO3 micro-nano powder content is low, the degradation of levofloxacin is poor, with a degradation rate of 84.78% after 30 minutes. With increasing BiFeO3 content, the degradation rate increases and then decreases. When the BiFeO3:NaNbO3 mass ratio is 2:3, the material achieves the best levofloxacin degradation, reaching 41.41% in just 60 minutes. This demonstrates efficient and rapid piezoelectric catalytic properties.

[0084] Table 6: Degradation rate of levofloxacin by composite piezoelectric catalytic materials with different ratios of BiFeO3 and NaNbO3

[0085]

[0086] (7) Effect of NaNbO3@BiFeO3 composite piezoelectric catalytic material on the degradation rate of paracetamol

[0087] Paracetamol was used as the target pollutant for degradation experiments. 5 mg of paracetamol was weighed and mixed with deionized water to prepare a paracetamol solution with an initial concentration of 25.0 mg / L. Example 3 was then added to a levofloxacin solution and magnetically stirred in the dark for 30 minutes to allow the paracetamol solution and powder particles to reach adsorption-desorption equilibrium. This suspension was then transferred to a reaction apparatus and activated by vibration under visible light irradiation at an ultrasonic frequency of 40 kHz and a power of 200-300 W to perform a piezoelectric photocatalytic reaction.

[0088] Figure 6 Table 7 shows the degradation rates of paracetamol by the NaNbO3@BiFeO3 composite piezoelectric catalytic material under different illumination times. Single

[001] -oriented NaNbO3 flakes showed poor paracetamol degradation, with a degradation rate of only 1.09% after 120 minutes. The BiFeO3-modified BiFeO3@NaNbO3 composite piezoelectric catalytic material significantly improved the degradation rate, reaching 14.18% in just 30 minutes and 59.09% after 120 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0089] Table 7 Degradation rate of paracetamol by NaNbO3@BiFeO3 composite piezoelectric catalytic material

[0090]

[0091]

[0092] (8) Effect of different ratios of NaNbO3@BiFeO3 composite piezoelectric catalytic materials on the degradation rate of paracetamol

[0093] 0.005g, 0.075g, 0.010g, 1.1025g, 0.015g, and 0.020g of BiFeO3 micro-nano powder and 0.015mg of

[001] -oriented NaNbO3 flakes were weighed, added to 50mL of anhydrous ethanol, and sonicated for 1 hour. The suspension was then placed in a magnetic stirrer for 24 hours and then dried in an 85°C oven for 10 hours. The suspension was then magnetically stirred in the dark for 30 minutes to allow the paracetamol solution to reach adsorption-desorption equilibrium with the powder particles. The suspension was then transferred to a reactor and activated by vibration under visible light irradiation at an ultrasonic frequency of 40kHz and a power of 200-300W to perform the piezoelectric photocatalytic reaction.

[0094] Figure 6 Table 8 shows the degradation rates of paracetamol using NaNbO3@BiFeO3 composite piezoelectric catalytic materials with different ratios. When the BiFeO3 micro-nano powder content is low, paracetamol degradation is poor, with a degradation rate of 1.0% after 30 minutes. With increasing BiFeO3 content, degradation increases initially and then decreases. When the BiFeO3:NaNbO3 mass ratio is 2.5:3, the material achieves the best paracetamol degradation, achieving a rate of 59.09%. Furthermore, when the BiFeO3:NaNbO3 mass ratio is 2.5:3, the degradation rate reaches 14.18% in just 30 minutes, demonstrating efficient and rapid piezoelectric catalytic properties.

[0095] Table 8: Degradation rate of paracetamol by different ratios of NaNbO3@BiFeO3 composite piezoelectric catalytic materials

[0096]

[0097]

[0098] (9) Effect of NaNbO3@BiFeO3 composite piezoelectric catalytic materials on the degradation rate of different antibiotics

[0099] Figure 7 Table 9 summarizes the degradation rates of oxytetracycline, carbamazepine, levofloxacin, and paracetamol using the BiFeO3 / NaNO3 composite piezoelectric catalytic material under 120 minutes of illumination. Due to differences in molecular structure and chemical properties, the degradation order of the four antibiotics was oxytetracycline > levofloxacin > carbamazepine > paracetamol. For the degradation of oxytetracycline, carbamazepine, levofloxacin, and paracetamol, the optimal mass ratios of BiFeO3 to NaNbO3 were 2:3, 1:3, 2:3, and 2.5:3, respectively, yielding degradation rates of 91.8%, 77.04%, 84.78%, and 59.09%, respectively. These results demonstrate that the NaNbO3@BiFeO3 composite piezoelectric catalytic material can degrade structurally diverse antibiotics with significant efficiency, laying a theoretical foundation for the practical application of NaNbO3@BiFeO3 composite piezoelectric catalytic materials.

[0100] Table 9: Degradation rate of different antibiotics by NaNbO3@BiFeO3 composite piezoelectric catalytic material under the same illumination time

[0101] antibiotic name <![CDATA[NaNbO3@BiFeO3]]> Degradation rate Oxytetracycline 2：3 91.80％ Carbamazepine 1：3 77.04％ Levofloxacin 2：3 84.78％ paracetamol 2.5：3 59.09％

[0102] The above embodiments are only for illustrating the technical concept and features of the present invention in a specific scenario. Its purpose is to enable people who need this technology to understand the content of the present invention and implement it. It does not limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite piezoelectric catalytic material for rapid degradation of antibiotics, characterized in that: The composite piezoelectric catalytic material is prepared from NaNbO3 and BiFeO3. The NaNbO3 is a [001] crystallographically oriented flaky grain prepared by a two-step molten salt method, and the BiFeO3 is a micro-nano particle prepared by a co-precipitation method.

2. The method for preparing a composite piezoelectric catalytic material NaNbO3@BiFeO3 for rapid degradation of antibiotics according to claim 1, characterized in that: The preparation method adopts the following steps: (1) Select Bi(NO3)3 with a purity greater than 99% . 5H2O, Fe(NO3)3 . 9H2O is used as the raw material for micro-nano BiFeO3 powder; the materials are weighed according to the stoichiometric ratio and stirred in a beaker for more than 5 hours; 1 mol / L NaOH solution is slowly added to the above solution to precipitate a solid precipitate under alkaline conditions; the above mixture is allowed to stand for 24-48 hours, washed with distilled water, filtered until neutral, and dried; the dried sample is placed in a high-temperature furnace for heat treatment at a temperature set at 500-550°C to obtain BiFeO3 micro-nano particles; (2) Select Bi2O3, Na2CO3, Nb2O5, and NaCl with a purity greater than 99% as raw materials for [001] crystallographically oriented NaNbO3 flake grains; weigh Bi2O3, Na2CO3, and Nb2O5 according to the stoichiometric ratio, add NaCl of the same mass as the mixture, use anhydrous ethanol as the ball milling medium, ball mill for 12 hours and dry, then place the mixture in a high-temperature furnace at 1100°C for 3 hours; after the reaction is complete, wash with deionized water to remove the sodium salt, and obtain Bi 2.5 Na 3.5 Nb5O 18 (BNN) precursor; the BNN precursor and Na2CO3 powder were mixed in a mass ratio of 6:1, and an equal mass of NaCl was added. After ball milling for 12 hours with anhydrous ethanol as the ball milling medium, the mixture was placed in a high-temperature furnace for insulation; the sintered product was washed with nitric acid and deionized water, respectively, to obtain [001]-oriented NaNbO3 flake grains; (3) BiFeO3 micro-nano particles and [001] oriented NaNbO3 flake grains were weighed in proportion, 20-100 mL of anhydrous ethanol was added, and the mixture was stirred on a magnetic stirrer after ultrasonication. NaNbO3 was obtained after drying. 33 @BiFeO composite piezoelectric catalytic material.

3. The method for preparing a composite piezoelectric catalytic material for rapid degradation of antibiotics according to claim 2, characterized in that: In the step (1), the BiFeO3 micro-nano particles are prepared by chemical co-precipitation, and the pH value required for the co-precipitation is 9-13.

4. The method for preparing a composite piezoelectric catalytic material for rapid degradation of antibiotics according to claim 2, characterized in that: In the step (2), the [001]-oriented NaNbO3 flake grains are prepared by a two-step molten salt method, the molten salt is NaCl with the same mass as the mixture powder, the precursor is BNN, the preparation temperature is 1100°C and the temperature is kept for 3 hours, and the product needs to be acid-washed and water-washed.

5. The method for preparing a composite piezoelectric catalytic material for rapid degradation of antibiotics according to claim 2, characterized in that: In the step (3), the BiFeO3 micro-nano particles and [001] oriented NaNbO3 flake grains need to be added with anhydrous ethanol and ultrasonically treated for 1 hour and then stirred for 12-48 hours.

6. The method for preparing a composite piezoelectric catalytic material for rapid degradation of antibiotics according to claim 2, characterized in that: The mass ratio of the BiFeO3 micro-nano powder to the [001] oriented NaNbO3 flake grains in step (3) is (0.25-3):

3.

7. Use of a composite piezoelectric catalytic material according to any one of claims 1 to 5 in the efficient and rapid degradation of antibiotics in wastewater.

8. Use of a composite piezoelectric catalytic material according to claim 6 for the efficient and rapid degradation of antibiotics in wastewater, characterized in that: The antibiotics include any one or more of oxytetracycline, levofloxacin, carbamazepine and paracetamol.

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