Synthesis method of lanthanide metal dominated high-entropy alloy and application thereof in electrochemical induction polymerization of tetracycline pollutants

Abstract

This invention discloses a method for synthesizing lanthanide-dominated high-entropy alloys and their application in the electrochemically induced polymerization of tetracycline-based pollutants, belonging to the fields of environmental functional materials and advanced wastewater treatment technology. Using lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and manganese nitrate as metal sources, and citric acid as a complexing and reducing agent, a high-entropy alloy powder with a single solid solution phase of La-Co-Ni-Cu-Mn is prepared through a sol-gel combined with inert atmosphere high-temperature calcination. The working electrode, prepared by coating this powder onto a conductive substrate, can be used for the electrochemically induced polymerization and transformation of tetracycline-based pollutants (such as chlortetracycline, tetracycline, and doxycycline). At low current densities, this electrode can rapidly convert tetracycline-based pollutants in water into insoluble polymers, achieving efficient and thorough removal of pollutants through simple filtration, effectively avoiding the drawbacks of traditional mineralization technologies such as high energy consumption, easy generation of toxic intermediate products, and CO2 emissions. This invention provides a green, efficient, and universally applicable new material and method for the advanced treatment of antibiotic-containing wastewater.

Description

Technical Field

[0001] This invention belongs to the field of environmental functional materials and advanced wastewater treatment technology, specifically relating to a method for synthesizing lanthanide-dominated high-entropy alloys and their application in electrochemically induced polymerization of tetracycline pollutants. Background Technology

[0002] Tetracycline antibiotics (TCs), as broad-spectrum antibacterial drugs, are widely used in the treatment of human diseases and in livestock and poultry farming. Due to their extensive use and the limitations of traditional biochemical treatment processes, they are frequently detected in pharmaceutical wastewater, livestock wastewater, and surface water, posing a potential threat to ecosystems and human health. Therefore, developing efficient and thorough TC pollution control technologies is of great significance.

[0003] Currently, the main technologies for treating total chemical substances (TCs) in wastewater include adsorption and advanced oxidation methods. Adsorption only achieves phase transfer of pollutants, and subsequent treatment with saturated adsorbents is costly and poses a risk of secondary pollution. Traditional advanced oxidation technologies, such as Fenton oxidation, photocatalysis, and electrocatalytic oxidation, rely on the core mechanism of using highly oxidizing free radicals generated during the reaction to non-selectively attack TC molecules, gradually oxidizing and decomposing (mineralizing) them into CO2 and H2O.

[0004] However, this type of mineralization technology has the following inherent drawbacks in practical applications: First, the mineralization process is energy-intensive and has a long reaction cycle, resulting in high treatment costs; second, TCs have complex molecular structures, and during oxidation, they easily generate a series of intermediate products with unknown structures, potentially higher toxicity than the parent compound, or still retaining biological activity, leading to an increase in effluent toxicity rather than a decrease, posing significant environmental safety risks; third, the final product after mineralization releases CO2, which is detrimental to carbon fixation. In recent years, electrochemically induced polymerization has attracted attention as an emerging pollutant removal strategy. This method induces coupling reactions between pollutant molecules through electrode reactions, generating water-insoluble macromolecular polymers, thereby achieving complete removal of pollutants through simple solid-liquid separation. This pathway avoids the generation of toxic intermediate products at the source and has the potential to be highly efficient, thorough, and environmentally friendly.

[0005] However, the core bottleneck of electrochemical polymerization technology lies in the lack of electrocatalytic electrode materials capable of specifically and efficiently inducing rapid polymerization reactions of tetracycline-based pollutants. Traditional electrode materials (such as Pt, BDD, and IrO2 / RuO2 coated electrodes) are mainly designed to enhance oxidation capabilities, resulting in low efficiency in inducing polymerization. High-entropy alloys, as a novel class of alloy materials composed of five or more principal metals in near equimolar ratios, exhibit excellent activity and stability in the catalytic field due to their unique "cocktail effect," severe lattice distortion, and tunable electronic structure. However, research on their application as functional electrode materials in the non-mineralization pathway of electrochemically induced pollutant polymerization transformation is currently lacking. Summary of the Invention

[0006] In view of this, the present invention aims to provide a method for synthesizing lanthanide-dominated high-entropy alloys and its application in electrochemically induced polymerization of tetracycline-based pollutants.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for synthesizing lanthanide-dominated high-entropy alloys, comprising the following steps: S1. Lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, manganese nitrate, citric acid, and solvent are mixed evenly to obtain a sol; S2. The sol was ultrasonically treated and vacuum dried to obtain a porous gel precursor; S3. The porous gel precursor was crushed and ground, and then calcined under an inert atmosphere to obtain high-entropy alloy powder.

[0009] Preferably, the molar ratio of lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, manganese nitrate, and citric acid in S1 is (0.6-1.4):(0.6-1.4):(0.6-1.4):(0.6-1.4):(3-7); more preferably, it is 1:1:1:1:1:5. In this invention, lanthanides (La) are the dominant elements, and their large atomic radii can cause significant lattice distortion, providing unique active sites for subsequent catalytic reactions. Co, Ni, Cu, and Mn are transition metals with good catalytic activity and conductivity. Their combination aims to produce a cocktail effect, meaning the overall performance of the alloy is far superior to the simple sum of the properties of the individual metals.

[0010] Citric acid molecules contain multiple carboxyl and hydroxyl groups, which can undergo complexation reactions with five metal ions in solution to form stable metal-citric acid complexes. This prevents metal ions from segregating or selectively precipitating in subsequent steps due to differences in their properties, ensuring that all metal ions are uniformly distributed at the molecular level. This is a prerequisite for synthesizing homogeneous high-entropy alloys.

[0011] Preferably, the solvent in S1 is a mixture of deionized water and anhydrous ethanol in a volume ratio of 20:4.

[0012] Preferably, the sol-liquid ratio in S1 is 3.4g:24mL.

[0013] Preferably, the ultrasonic treatment in S2 has a power of 600W and a duration of 10-15min.

[0014] Preferably, the vacuum drying temperature in step S2 is 85-95℃ and the time is 40-50h.

[0015] Preferably, the particle size in S3 is 220 mesh.

[0016] Preferably, the calcination temperature in S3 is 900-1100℃, the heating rate is 5℃ / min, and the calcination time is 55-65min.

[0017] At high temperatures, organic compounds such as citric acid undergo carbonization and vaporization. Metal nitrates also decompose, generating nitrogen oxide gases. The escape of these gases further creates pores and carries away non-metallic components. Under the influence of high temperature and the reduction effect of carbon, metal oxides are gradually reduced to elemental metals. Because the five metal atoms have achieved a homogeneous mixture at the molecular level in the previous steps, they gain sufficient energy for diffusion at high temperatures and tend to form a single solid solution phase with the lowest energy (high-entropy alloy), rather than splitting into multiple intermetallic compounds. This is the key thermodynamic and kinetic process in the formation of high-entropy alloys.

[0018] At temperatures around 1000℃, the alloy grains formed will gradually grow larger, and the crystallinity will increase.

[0019] Preferably, the inert atmosphere in S3 is a nitrogen atmosphere.

[0020] This invention also provides the application of high-entropy alloys obtained by the high-entropy alloy synthesis method in the electrochemically induced polymerization of tetracycline-based pollutants.

[0021] As a preferred option, high-entropy alloys are prepared as electrodes for electrochemical induction; The electrode is prepared by mixing high-entropy alloy powder with a binder to form a slurry, which is then coated onto a conductive substrate to form a working electrode.

[0022] It contains at least the following beneficial technical effects: This invention is the first to apply high-entropy alloy materials to the field of electrochemically induced polymerization, overturning the traditional "oxidation-mineralization" approach to pollutant removal and pioneering a new "electrode catalysis-polymerization-separation" model. This method directly converts dissolved tetracycline pollutants into insoluble polymers, which can then be separated from water through simple filtration. This completely avoids the generation and residue risks of toxic / reactive intermediates in traditional advanced oxidation processes, achieving true harmlessness and complete removal of pollutants.

[0023] The lanthanide-dominated pentagonal high-entropy alloy (La-Co-Ni-Cu-Mn) electrode synthesized in this invention exhibits extremely high electrochemical polymerization catalytic activity for tetracycline pollutants due to its unique electronic structure and multi-metal synergistic catalytic effect. Experimental results show that, at low current densities, for various tetracycline pollutants (such as chlortetracycline, tetracycline, and doxycycline) at concentrations of 10 mg / L, the removal rate can exceed 80% within 1 minute, and the removal is essentially complete (>99%) within 10 minutes. The treatment speed far exceeds that of traditional mineralization technologies that require tens of minutes or even hours, significantly improving wastewater treatment efficiency.

[0024] A La-based pentagonal high-entropy alloy solid solution phase with uniform composition and simple structure was successfully prepared using the sol-gel combined high-temperature calcination method described in this invention. This material exhibits low charge transfer resistance (EIS characterization) and abundant catalytic active sites, demonstrating not only high catalytic activity but also excellent electrochemical stability under high current density or long-term operating conditions, showing promising prospects for industrial applications.

[0025] The method of this invention can efficiently drive the polymerization reaction at a low current density (e.g., 5 mA), with energy consumption far lower than that of traditional electrochemical oxidation mineralization processes. After the reaction, the pollutants precipitate in the form of solid polymers, and solid-liquid separation can be achieved through simple settling, filtration, or centrifugation. The process is simple and inexpensive.

[0026] The electrode material developed in this invention exhibits highly efficient polymerization removal capabilities for various structurally similar tetracycline antibiotics (chlortetracycline, tetracycline, doxycycline, oxytetracycline, etc.), demonstrating broad applicability. It can be widely applied to the advanced treatment of pharmaceutical wastewater, aquaculture wastewater, and polluted surface water, opening up new directions for the application of high-entropy alloys in environmental catalysis. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the high-entropy alloy synthesis steps; Figure 2 Scanning electron microscope image of a high-entropy alloy; Figure 3 XRD pattern of LaCoNiCuMn high-entropy alloy; Figure 4Raman plot of LaCoNiCuMn high-entropy alloy; Figure 5 Image showing the effect of using electrodes to remove various tetracycline contaminants; Figure 6 Electrochemical impedance spectroscopy (EIS) for LaCoNiCuMn high-entropy alloy. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0034] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0035] The raw materials used in this invention are as follows: lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and manganese nitrate, all of which are analytical grade (Aladdin reagent, >99.5%), and ethanol (Maclean's, >99.8%).

[0036] Example 1 S1. Preparation of Sol Accurately weigh 2 mmol each of lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and manganese nitrate into a 100 mL beaker. Weigh 10 mmol of citric acid and add it to the beaker. Measure 20 mL of deionized water and 4 mL of anhydrous ethanol and add them to the beaker as a mixed solvent. Place the beaker on a magnetic stirrer and stir continuously at 200 rpm for 12 hours at room temperature to allow all components to fully dissolve and undergo a complexation reaction, forming a uniform, transparent, purple-red sol.

[0037] S2. Preparation of porous gel precursors The sol obtained in step S1 was transferred to a petri dish and ultrasonically treated for 12 minutes in an ultrasonic cleaner to remove any microbubbles that might be present in the solution and to further homogenize it. Subsequently, the petri dish was quickly placed in a vacuum drying oven and vacuum dried at 90°C for 48 hours. As the solvent slowly evaporated, the sol gradually transformed into a gel, eventually yielding a fluffy, porous dry gel block, which is the porous gel precursor.

[0038] S3. Preparation of high-entropy alloy powder The porous gel precursor block obtained in step S2 was transferred to an agate mortar and ground thoroughly into a fine powder (220 mesh). The ground precursor powder was evenly spread in a quartz boat, which was then pushed into the center of the quartz tube of a tube furnace. Under an inert atmosphere of continuously purging high-purity nitrogen (flow rate of 100 mL / min), the temperature was programmed to rise to 1000℃ at a rate of 5℃ / min and held at this temperature for 60 minutes for calcination alloying. After calcination, the temperature was programmed to cool to room temperature at a rate of 5℃ / min. The quartz boat was removed, and the resulting dark gray powder was collected; this is the La-Co-Ni-Cu-Mn pentagonal high-entropy alloy.

[0039] Example 1 shows the synthesis of a La-Co-Ni-Cu-Mn pentagonal high-entropy alloy. Figure 2 The synthesis of high-entropy alloy solid particles was shown. Figure 3 XRD showed that a single solid solution phase was successfully formed. Figure 4 Raman spectroscopy characterizes its structure, revealing abundant active sites and an optimized electronic structure. Figure 6 EIS showed that it has low charge transfer resistance, high catalytic activity, and good stability.

[0040] Example 2 S1. Preparation of Sol Accurately weigh 2 mmol each of lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and manganese nitrate into a 100 mL beaker. Weigh 10 mmol of citric acid and add it to the beaker. Measure 20 mL of deionized water and 4 mL of anhydrous ethanol and add them to the beaker as a mixed solvent. Place the beaker on a magnetic stirrer and stir continuously at 200 rpm for 12 hours at room temperature to allow all components to fully dissolve and undergo a complexation reaction to form a homogeneous sol.

[0041] S2. Preparation of porous gel precursors The sol obtained in step S1 was transferred to a petri dish and ultrasonically treated for 10 minutes in an ultrasonic cleaner to remove any microbubbles that may be present in the solution and to further homogenize it. Subsequently, the petri dish was quickly placed in a vacuum drying oven and vacuum dried at 85°C for 40 hours. As the solvent slowly evaporated, the sol gradually transformed into a gel, eventually yielding a fluffy, porous dry gel block, which is the porous gel precursor.

[0042] S3. Preparation of high-entropy alloy powder The porous gel precursor block obtained in step S2 was transferred to an agate mortar and ground thoroughly into a fine powder (220 mesh). The ground precursor powder was evenly spread in a quartz boat, which was then pushed into the center of the quartz tube of a tube furnace. Under an inert atmosphere of continuously purging high-purity nitrogen (flow rate of 100 mL / min), the temperature was programmed to rise to 900°C at a rate of 5°C / min, and held at this temperature for 55 minutes for calcination alloying. After calcination, the temperature was programmed to cool to room temperature at a rate of 5°C / min. The quartz boat was removed, and the resulting dark gray powder was collected; this is the La-Co-Ni-Cu-Mn pentagonal high-entropy alloy.

[0043] Example 3: S1. Preparation of Sol Accurately weigh 2 mmol each of lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, and manganese nitrate into a 100 mL beaker. Weigh 10 mmol of citric acid and add it to the beaker. Measure 20 mL of deionized water and 4 mL of anhydrous ethanol and add them to the beaker as a mixed solvent. Place the beaker on a magnetic stirrer and stir continuously at 200 rpm for 12 hours at room temperature to allow all components to fully dissolve and undergo a complexation reaction to form a homogeneous sol.

[0044] S2. Preparation of porous gel precursors The sol obtained in step S1 was transferred to a petri dish and ultrasonically treated for 15 minutes in an ultrasonic cleaner to remove any microbubbles that might be present in the solution and to further homogenize it. Subsequently, the petri dish was quickly placed in a vacuum drying oven and vacuum dried at 95°C for 50 hours. As the solvent slowly evaporated, the sol gradually transformed into a gel, eventually yielding a fluffy, porous dry gel block, which is the porous gel precursor.

[0045] S3. Preparation of high-entropy alloy powder The porous gel precursor block obtained in step S2 was transferred to an agate mortar and ground thoroughly into a fine powder (220 mesh). The ground precursor powder was evenly spread in a quartz boat, which was then pushed into the center of the quartz tube of a tube furnace. Under an inert atmosphere of continuously purging high-purity nitrogen (flow rate of 100 mL / min), the temperature was programmed to rise to 1100℃ at a rate of 5℃ / min and held at this temperature for 65 minutes for calcination alloying. After calcination, the temperature was programmed to cool to room temperature at a rate of 5℃ / min. The quartz boat was removed, and the resulting dark gray powder was collected, which is the La-Co-Ni-Cu-Mn pentagonal high-entropy alloy.

[0046] Example 4 The preparation method in this embodiment is the same as that in the previous embodiment, except that the calcination temperature of S3 is 900℃.

[0047] Electrochemical analysis (EIS) showed that its charge transfer resistance was slightly higher than that of the sample in Example 1. In the same degradation experiment, the removal rate of tetracycline was approximately 75% after 1 minute and approximately 95% after 10 minutes. This indicates that calcination at 1000℃ is more conducive to the formation of a uniform high-entropy alloy phase, thereby obtaining better catalytic performance.

[0048] Example 5 The preparation method in this embodiment is the same as that in the previous embodiment, except that the amount of lanthanum nitrate is 2.4 mmol, the amount of cobalt nitrate is 1.6 mmol, and the amounts of nickel nitrate, copper nitrate, and manganese nitrate are 2 mmol each.

[0049] Degradation experiments showed that its polymerization removal efficiency for doxycycline was comparable to that of Example 1, but its removal rate for oxytetracycline was slightly improved. This indicates that, in the presence of the dominant element La, fine-tuning the proportion of transition metals can optimize the catalytic performance of specific pollutants, demonstrating the flexibility advantage of adjustable high-entropy alloy composition.

[0050] Experimental Example 1 X-ray diffraction analysis and laser Raman spectroscopy analysis were performed on the La-Co-Ni-Cu-Mn pentagonal high-entropy alloy obtained in Example 1. like Figure 3The La-Co-Ni-Cu-Mn pentagonal high-entropy alloy obtained in Example 1 shown successfully formed a single solid solution phase. Figure 4 Raman spectroscopy characterizes its structure, revealing abundant active sites and an optimized electronic structure.

[0051] Experimental Example 2 Tetracycline pollutant removal efficiency test Experimental methods: Electrode preparation: The high-entropy alloy powder of Example 1 was mixed with a binder to form a slurry, which was then coated onto a conductive substrate to form a working electrode.

[0052] I. Substrate Pretreatment (Carbon Paper) 1. Solvent ultrasonic cleaning: Immerse the carbon paper substrate, cut to 1×21×2 cm, in anhydrous ethanol and ultrasonically treat for 10 minutes. This step aims to remove organic contaminants adhering to the substrate surface.

[0053] 2. First cleaning: Rinse the carbon paper thoroughly with deionized water to remove any residual ethanol.

[0054] 3. Secondary ultrasonic cleaning: Immerse the rinsed carbon paper in deionized water and ultrasonically treat it again for 10 minutes. This step aims to remove residual inorganic impurities and activate the carbon paper surface to enhance the adhesion of subsequent pastes.

[0055] 4. Drying: Place the cleaned carbon paper in a 60℃ oven to dry for later use.

[0056] II. Catalyst Slurry Preparation 1. Material mixing: Accurately weigh 10 mg of the high-entropy alloy powder described in Example 1 as the active material.

[0057] 2. Binder and solvent preparation: Accurately measure Nafion perfluorosulfonic acid resin solution and anhydrous ethanol at a volume ratio of 50:950 and premix them as a dilution and dispersion medium. This ratio is intended to control the solid content and rheological properties of the final slurry.

[0058] 3. Ultrasonic dispersion: The weighed high-entropy alloy powder is added to the above mixed solvent and ultrasonically dispersed for 10 minutes at an ultrasonic power of 500 W. This operation aims to utilize the cavitation effect of ultrasound to uniformly and stably disperse the catalyst particles in the binder solution, forming a homogeneous suspension (catalyst slurry).

[0059] III. Drop casting and thermosetting 1. Preheating the substrate: Place the carbon paper substrate, which has been pretreated and dried in step 1, on a constant temperature heating table and preheat it at 100°C. Preheating helps the solvent evaporate quickly and prevents the slurry from excessively penetrating into the substrate.

[0060] 2. Quantitative Drop Coating: Using a dropper, slowly and evenly drop the catalyst slurry prepared in step 2 onto the preheated carbon paper surface in multiple applications. During the operation, the drop rate must be controlled to ensure the slurry spreads evenly on the substrate surface, forming a complete film and avoiding the "coffee ring" effect.

[0061] 3. Gradual drying and curing: a. First stage drying: After drop coating, transfer the electrode to a 60°C oven and dry for 1 hour. This low-temperature, slow drying stage aims to slowly remove most of the solvent, preventing cracks in the film due to rapid solvent evaporation.

[0062] b. Second-stage thermosetting: The oven temperature is then raised to 120°C, and drying continues for 2 hours. This high-temperature curing stage aims to promote complete film formation of the Nafion binder, creating a stable three-phase reaction interface and ensuring excellent adhesion between the catalyst layer and the substrate.

[0063] 4. Experimental Procedure a. Material preparation Weigh an appropriate amount of tetracycline-related pollutants (such as tetracycline, oxytetracycline, chlortetracycline, etc.) and dissolve them in deionized water to prepare a simulated wastewater solution with a concentration of 20 mg / L. Anhydrous sodium sulfate (Na₂SO₄, analytical grade) is used as the electrolyte, and an electrolyte solution with a concentration of 0.1 mol / L is prepared. The anode material is a high-entropy alloy material supported on carbon paper, with dimensions of 1 cm × 2 cm; the cathode is a stainless steel electrode sheet with dimensions of 2 cm × 4 cm. Before use, the electrodes are ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water to remove surface impurities, and then dried before use.

[0064] b. Reactor Construction A single-chamber reactor with an effective volume of 150 mL was used. The pretreated anode and cathode were fixed parallel to each other in the reactor, with an electrode spacing of 1.5 cm. An electrolyte solution containing tetracycline contaminants was added to the reactor, ensuring the electrodes were completely submerged.

[0065] c. Electrochemical treatment Connect the anode and cathode to a DC power supply via wires, set the output current to 10 mA, and start the reaction. During the reaction, use a magnetic stirrer to continuously stir at an appropriate speed to ensure the solution is thoroughly mixed. The reaction time is 10 minutes; observe and record the changes in the appearance of the reaction system during this period.

[0066] d. Post-reaction treatment and observation of phenomena After the reaction is complete, turn off the power and transfer the post-reaction solution to a glass container to stand. Observe and record the formation, color change, and sedimentation behavior of the polymer in the system. Filter the post-reaction mixture using ordinary filter paper or a microporous membrane to examine the polymer separation characteristics.

[0067] 5. Results Analysis a. Polymer formation and separation characteristics like Figure 5 As shown, experimental results indicate that after reacting for 10 minutes at a current density of 10 mA, all tetracycline pollutants in the system rapidly transformed into a yellow polymer precipitate. This polymer remained suspended in solution and could be efficiently separated by simple filtration, resulting in clear, transparent water with no visible residue. Further observation during settling revealed that the polymer spontaneously and significantly settled within one hour after the reaction, producing a clear supernatant that significantly reduced the difficulty of subsequent treatment.

[0068] b. Removal effect analysis The above phenomena indicate that, under the electrocatalysis of a high-entropy alloy anode, tetracycline pollutants undergo efficient polymerization in a short time, rather than the mineralization decomposition common in traditional electrochemical oxidation pathways. This polymerization pathway significantly reduces the water solubility of pollutants, transforming them into easily separable solid products. Compared to traditional advanced oxidation methods, this method requires no additional oxidant, consumes less energy, operates under milder reaction conditions, and avoids secondary pollution.

[0069] c. Deduction of polymerization reaction mechanism High-entropy alloy materials exhibit a synergistic effect of multiple active sites, enabling the efficient generation of highly oxidizing reactive species (such as hydroxyl radicals and sulfate radicals) on the anode surface, which initiates the free radical polymerization of tetracycline molecules. Tetracycline molecules contain multiple active functional groups (such as phenolic hydroxyl groups and enol hydroxyl groups), which undergo cross-linking polymerization under the action of electrochemically induced free radicals, forming large polymer molecules with significantly increased molecular weights, which ultimately precipitate from the aqueous phase.

[0070] d. Summary of technical advantages This method utilizes a simple single-chamber reactor structure, eliminating the need for ion exchange membranes and reducing system internal resistance and operating costs. The anode is made of a high-entropy alloy material, exhibiting excellent electrocatalytic activity and stability, enabling efficient polymerization removal of tetracycline pollutants at low current densities. This method combines high treatment efficiency, ease of operation, convenient separation, and no secondary pollution, making it particularly suitable for the rapid treatment of antibiotic-containing organic wastewater and demonstrating promising application prospects.

[0071] Experimental Example 3 The test was conducted at room temperature, using a 0.1 M Na₂SO₄ aqueous solution as the electrolyte. High-purity nitrogen was purged for 15 minutes before the test to remove oxygen. A three-electrode system was used: a saturated calomel electrode (SCE) as the reference electrode, a platinum electrode as the counter electrode, and a high-entropy alloy electrode as the working electrode. Before electrochemical impedance spectroscopy (EIS), the open-circuit potential (OCP) was measured for 1800 seconds until the potential change was less than 1 mV / min. The stabilized open-circuit potential was recorded as the test baseline.

[0072] The EIS test uses a constant potential mode, with the DC bias potential set to the measured open-circuit potential, and the AC excitation signal amplitude at 10 mV rms. The sweep frequency range is from high frequency 100,000 Hz (10 5 From 10 mHz (10 MHz) to 10 mHz (0.01 Hz), 10 frequency points were collected every ten octaves, with the frequency sweep direction from high to low. During the test, a 5-second wait time was set before each frequency point to stabilize the response, and three single-frequency averages were used to reduce noise.

[0073] After the test is completed, an equivalent circuit fitting analysis is performed on the EIS data.

[0074] like Figure 6 As shown, the Nyquist plots of the electrochemical impedance spectroscopy of three high-entropy alloy samples are presented, with the horizontal axis representing the real impedance Z′ and the vertical axis representing the imaginary impedance. Z′′. The three samples are LaCoNiCuMn (pentagonal marking), LaCoNi (dot marking), and CoNiCuMn (triangular marking). From the spectral characteristics, all three curves show a typical combination of a semicircle in the high-frequency region and a sloping straight line in the low-frequency region. The diameter of the high-frequency semicircle approximately reflects the magnitude of the charge transfer resistance Rct, while the low-frequency sloping line corresponds to the ion diffusion process and is related to the Warburg impedance.

[0075] A comparison of the curve positions and semicircle sizes of the three samples reveals significant differences. The CoNiCuMn curve is located almost entirely on the right, with the largest radius of the high-frequency semicircle, indicating the highest charge transfer resistance and the slowest interfacial reaction kinetics. The LaCoNi curve is in the middle, with a semicircle diameter between the two, indicating a moderate charge transfer impedance. The LaCoNiCuMn curve is furthest to the left, with the smallest initial real part impedance and the smallest high-frequency semicircle diameter, indicating the lowest charge transfer resistance, the fastest electron and charge transport rate, and the optimal interfacial reaction kinetics.

[0076] Based on the dimensions of the semicircles in the figure, the order of charge transfer resistance can be summarized as: CoNiCuMn > LaCoNi > LaCoNiCuMn. This result indicates that LaCoNiCuMn performs best in terms of electrochemical reaction kinetics, followed by LaCoNi, while CoNiCuMn performs worst.

[0077] In the low-frequency region, all three curves exhibit sloping straight-line tails, indicating the presence of ion diffusion-controlled processes in the system. The degree of sloping of the low-frequency lines is closely related to diffusion behavior; a curve closer to the vertical direction suggests more ideal capacitive behavior and smoother ion transport. Based on the trends in the figures, LaCoNiCuMn not only performs well in the low-frequency region but also exhibits the lowest overall impedance, suggesting it may possess a faster charge transfer rate, lower interfacial impedance, and superior ion diffusion capability.

[0078] Based on the above EIS analysis results, if this material is used for electrode performance evaluation, it can be determined that LaCoNiCuMn has the smallest interfacial impedance and the fastest charge transfer kinetics, indicating its superior rate performance and electrochemical activity; LaCoNi performs in the middle; while CoNiCuMn has the largest impedance and the worst reaction kinetics.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for synthesizing high-entropy alloys dominated by lanthanides, characterized in that, Includes the following steps: S1. Lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, manganese nitrate, citric acid, and solvent are mixed evenly to obtain a sol; S2. The sol was ultrasonically treated and vacuum dried to obtain a porous gel precursor; S3. The porous gel precursor was crushed and ground, and then calcined under an inert atmosphere to obtain high-entropy alloy powder.

2. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The molar ratio of lanthanum nitrate, cobalt nitrate, nickel nitrate, copper nitrate, manganese nitrate, and citric acid in S1 is (0.6-1.4):(0.6-1.4):(0.6-1.4):(0.6-1.4):(0.6-1.4):(3-7).

3. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The solvent in S1 is a mixture of deionized water and anhydrous ethanol in a volume ratio of 20:

4.

4. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The solid-liquid ratio of the sol in S1 is 3.4g:24mL.

5. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The ultrasonic treatment in S2 has a power of 500-800W and a duration of 10-15min.

6. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The vacuum drying in S2 is performed at a temperature of 65-95℃ for 40-50 hours.

7. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The particle size of the powder in S3 is 150-280 mesh.

8. The method for synthesizing high-entropy alloys according to claim 1, characterized in that, The calcination temperature in S3 is 900-1100℃, the heating rate is 5℃ / min, and the calcination time is 55-65min.

9. The application of the high-entropy alloy obtained by the high-entropy alloy synthesis method according to any one of claims 1-8 in the electrochemically induced polymerization of tetracycline-based pollutants.

10. The application according to claim 9, characterized in that, High-entropy alloys were used as electrodes for electrochemical induction. The electrode is prepared by mixing high-entropy alloy powder with a binder to form a slurry, which is then coated onto a conductive substrate to form a working electrode.

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