Preparation of nitrogen-rich carbide piezoelectric composite material and application thereof in water purification and bacterium inhibition

Abstract

The present application relates to the sewage treatment technical field, specifically relates to a kind of preparation and application in water purification bacteriostasis of nitrogen-rich carbide piezoelectric composite material.The present application is coupled by high molecular piezoelectric polymer and nitrogen-rich carbide, and modified piezoelectric composite material with high piezoelectric catalytic activity is formed, and the efficient degradation of various organic pollutants in water is realized by driving force induction piezoelectric effect, and has excellent bacteriostatic performance.The preparation process in the present application is simple, green, low cost, material mechanical strength is high, degradation process is free of secondary pollution, easy to mass production, the method can effectively solve water pollution problem, help ecological environment protection, and escort for human health.

Description

[Technical Field]

[0001] This invention relates to the preparation of a nitrogen-rich carbide piezoelectric composite material and its application in water purification and antibacterial treatment, belonging to the field of wastewater treatment technology. [Background Technology]

[0002] Environmental pollution and energy shortage are two major challenges facing our time. With continuous economic development, large amounts of harmful chemicals are released into the natural environment, leading to increasingly severe water pollution problems and posing a serious threat to ecosystems and human health. Therefore, how to efficiently remove micropollutants from water bodies has become an urgent problem to be solved. To date, various physical and chemical technologies, such as adsorption, photocatalytic oxidation, electrocatalysis, and membrane separation, have been explored for the degradation of organic pollutants. However, these technologies inevitably suffer from high energy consumption, harsh reaction conditions, susceptibility to secondary pollution, and difficulty in large-scale application, limiting their development and application. Therefore, finding an effective and sustainable method to remove micropollutants from water is crucial for protecting the environment and human health.

[0003] In recent years, piezoelectric catalysis has emerged as a novel wastewater treatment technology, boasting advantages such as no chemical additives, low energy consumption, and high efficiency in degrading organic pollutants. This technology can widely harvest environmental energy, such as muscle energy, wind energy, solar energy, water flow energy, and noise, converting this ubiquitous mechanical energy into electrochemical energy through strain or stress-induced piezoelectric effects. This enables the efficient degradation of micro-pollutants in water, demonstrating enormous application potential and becoming a focus of widespread research attention. Consequently, a series of piezoelectric catalytic materials with excellent activity have been developed, including semiconductor materials such as ZnO, BiTiO3, MoS2, WS2, and CdS. However, these semiconductor piezoelectric materials suffer from drawbacks such as insufficient piezoelectric polarization, scarce active sites, and difficulties in powder recovery, limiting their practical applications. Therefore, researchers have begun to focus on the research of modified composite piezoelectric catalytic materials.

[0004] In recent years, graphitic carbon nitride (CN) materials have attracted widespread attention from researchers due to their excellent chemical stability, controllable band gap, and non-toxicity, showing broad application prospects in energy storage, photocatalysis, and piezoelectric catalysis. Compared with traditional inorganic piezoelectrics, graphitic carbon nitride (CN) exhibits stronger piezoelectric polarization and rich structural tunability. However, the severe charge recombination, low electronic conductivity, and scarce active sites in bulk CN hinder further improvement of its piezoelectric catalytic performance. Therefore, studying and optimizing the piezoelectric catalytic performance of carbon nitride materials to achieve efficient degradation of micropollutants in water is of great significance.

[0005] Polyvinylidene fluoride (PVDF) and its copolymers are common high-molecular-weight piezoelectric polymers with wide applications in water treatment. Their excellent flexibility, good processability, and chemical stability make them ideal substrates for combining with semiconductor nanomaterials to produce composite piezoelectric catalytic materials. By combining piezoelectric PVDF with graphitic carbon nitride materials, a composite material with dual piezoelectric properties is obtained. Utilizing the band gap difference and dual piezoelectric effect of the two materials, electron / hole separation is promoted, thereby enhancing the piezoelectric catalytic performance of the material.

[0006] In summary, this invention aims to provide an application of a nitrogen-rich carbide piezoelectric composite material. The main difference between this invention and other technologies lies in the design of a nitrogen-rich carbide piezoelectric composite material. A high-molecular-weight piezoelectric polymer is coupled with a nitrogen-rich carbide C3N5 to form a modified composite piezoelectric material with high-voltage electrocatalytic activity. This material achieves efficient degradation of organic pollutants in water through a piezoelectric effect induced by a driving force. Compared with other technologies, this method has the following advantages: First, the material synthesis process is simple, green, non-toxic, and low-cost; second, it has low energy consumption during water purification, helping to save energy and reduce costs; third, the prepared modified piezoelectric composite material has good stability and high mechanical strength, making it easier to achieve industrial applications. In conclusion, this invention provides a promising material and method for achieving efficient degradation of organic pollutants in the field of wastewater treatment, with great application potential. [Summary of the Invention]

[0007] [Technical problem to be solved]

[0008] This invention aims to address the problems of low catalytic activity, high energy consumption, harsh reaction conditions, and easy secondary pollution associated with existing piezoelectric catalytic materials for water treatment. To this end, a method for efficiently degrading micropollutants in water is proposed. This method significantly enhances the piezoelectric catalytic performance of the material by coupling a simple, green, and non-toxic nitrogen-rich carbide, C3N5, with a high-molecular-weight piezoelectric polymer with excellent piezoelectric properties, resulting in good stability and high mechanical strength.

[0009] [Technical Solution]

[0010] The preparation of a nitrogen-rich carbide piezoelectric composite material and its application in water purification and antibacterial treatment include the following steps:

[0011] (1) 3-amino-1,2,4-triazole is placed in a covered crucible and transferred to a muffle furnace. It is calcined at 500-550℃ for 3-5 hours in an air atmosphere with a heating rate of 5-10℃ / min. After holding at the temperature for 2-5 hours, it is cooled and ground for later use.

[0012] (2) Dissolve 2-10g of the powder sample obtained in step (1) in 0.1-1mol / L alkaline salt solution and stir continuously until dissolved to obtain a suspension; transfer the suspension to a reaction vessel and react at 120-150℃ for 12-24 hours; after the reaction is completed, wash with deionized water and ethanol until the filtrate is transparent and colorless, and dry in an oven at 60-80℃ for 12-24 hours to obtain nitrogen-rich carbide C3N5;

[0013] (3) Weigh 1-5g of piezoelectric polymer powder and 0.1-1g of C3N5 powder at a mass ratio of 1:10-50, dissolve them in 10-50ml of organic solvent, place them in a water bath, stir at 60-70℃ for 1-3h until completely dissolved, and disperse under ultrasonic conditions for 30-60min to obtain a uniform piezoelectric polymer base liquid;

[0014] (4) Take 10-100 ml of the above piezoelectric polymer base liquid and mix it evenly with deionized water. The liquid is solidified by phase inversion method to obtain different forms of nitrogen-rich carbide piezoelectric composite materials.

[0015] (5) Take an appropriate amount of the above piezoelectric composite material and place it in the piezoelectric catalytic system to determine its piezoelectric catalytic performance: The specific operation is as follows: add the piezoelectric composite material to a pollutant aqueous solution with a volume of 20-200 ml, induce the piezoelectric effect through different driving forces, react for 0.25-1 h, take the supernatant and filter it through a filter membrane to determine the concentration of the target pollutant;

[0016] (6) Gram-negative *Escherichia coli* was selected as the test bacteria, and the antibacterial properties of the nitrogen-rich carbide piezoelectric composite material were evaluated using a co-culture method. Before sterilization, all test materials were sterilized at high temperature in an autoclave. The prepared piezoelectric composite material was placed in 10-100 ml of bacterial suspension, and a certain amount of the bacterial solution was evenly spread onto trypsin agar. The mixture was incubated at 37°C for 16-48 h, and quantitative bacterial counting was performed to calculate the bacterial density.

[0017] 2. The alkaline salt solution in step (2) can be one of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution or ammonia solution.

[0018] 3. The organic solvent in step (3) can be any one of N,N-dimethylformamide, N-methylpyrrolidone, and dimethylthionite.

[0019] 4. The piezoelectric polymer in step (3) can be any one of polyvinylidene fluoride (PVDF) and its copolymers (vinylidene fluoride-trifluoroethylene)(P(VDF-TrFE)) and poly(vinylidene fluoride-hexafluoropropylene)(P(VDF-HFP)).

[0020] 5. In step (4), the mixing method of piezoelectric polymer base liquid and deionized water can be uniform spraying or uniform rotation propulsion in the pipeline. The resulting piezoelectric composite material can be in the form of a thin film, microspheres, or attached to the inner wall of the pipeline to form a piezoelectric composite pipeline.

[0021] 6. The organic pollutants in step (5) include antibiotics such as ciprofloxacin hydrochloride, oxytetracycline, ofloxacin, chlortetracycline, and tetracycline, as well as organic dyes such as methylene blue and rhodamine B.

[0022] 7. The driving method in step (5) is one of the following: water flow, ultrasound, stirring, ball milling, etc.

[0023] [Beneficial Effects]

[0024] Compared with the prior art, the present invention has the following main advantages:

[0025] (1) The preparation method of the nitrogen-rich carbide piezoelectric composite material provided by the present invention is simple, green and non-toxic, and low in cost. The composite material has good stability and high mechanical strength.

[0026] (2) The nitrogen-rich carbide piezoelectric composite material provided by the present invention has excellent piezoelectric properties and is universal. It can efficiently degrade a variety of micro pollutants in water. The degradation process has no secondary pollution, high reusability, and is easier to realize industrial application.

[0027] (3) The nitrogen-rich carbide piezoelectric composite material provided by the present invention has excellent antibacterial properties, can achieve water purification effect, and meets environmental protection requirements. [Attached Image Description]

[0028] Figure 1 SEM image of the C3N5 / PVDF piezoelectric composite material prepared in this invention

[0029] Figure 2 The effect curve of the C3N5 / PVDF piezoelectric composite material prepared in this invention on the catalytic degradation of micropollutants in water.

[0030] Figure 3 The catalytic degradation effect curves of C3N5 / PVDF-TrFE and C3N5 / PVDF-HFP piezoelectric composite materials prepared in this invention on micropollutants in water.

[0031] Figure 4 Antibacterial properties of the C3N5 / PVDF-HFP piezoelectric composite material prepared in this invention (image)

Detailed Implementation Methods

[0032] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the present invention will be further described in detail below through specific embodiments. It should be noted that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0033] Example 1:

[0034] The preparation and application of a nitrogen-rich carbide piezoelectric composite material in water purification and antibacterial treatment are described below.

[0035] (1) Weigh 20g of the precursor 3-amino1,2,4-triazole and place it in a covered crucible. Transfer it to a muffle furnace and calcine it at 500℃ for 4 hours in an air atmosphere. The heating rate is 5℃ / min. After holding at the temperature for 3 hours, cool and grind it for later use.

[0036] (2) Weigh 5g of the powder sample obtained in step (1), dissolve 1.8g of NaOH in 200mL of deionized water, and stir continuously until dissolved to obtain a suspension; transfer the suspension to a 250ml polytetrafluoroethylene reactor and react at 120℃ for 12 hours; after the reaction is completed, wash with deionized water and ethanol until the filtrate is transparent and colorless, and dry in an oven at 60℃ for 12 hours to obtain nitrogen-rich carbide C3N5;

[0037] (3) Weigh 2g of polyvinylidene fluoride (PVDF) powder and 0.2g of C3N5 powder prepared in step (2), dissolve them in 20mL of N,N-dimethylformamide solvent, place them in a water bath, stir at 60℃ for 1h until completely dissolved, disperse under ultrasonic conditions for 30min to obtain a uniform piezoelectric polymer base liquid.

[0038] (4) Take 20 ml of the above piezoelectric polymer base liquid and inject it into a 1 m long pipe by rotating and pushing. Repeat the rotation 20 times and push deionized water in the same way. The liquid solidifies through phase conversion, so that the piezoelectric composite material is uniformly attached to the inner wall of the pipe to form a C3N5 / PVDF piezoelectric composite pipe.

[0039] (5) At room temperature, take 200 mL of a 5 mg / L pollutant aqueous solution and let it flow through a 1 m long C3N5 / PVDF piezoelectric composite pipe driven by a peristaltic pump. The pollutant degradation is driven by the water flow. Every 5 minutes, use a syringe to measure 3 mL of the reaction solution, filter it through a filter membrane, and measure the concentration of organic pollutants. The removal effect is shown in [see figure]. Figure 2 The results show that the C3N5 / PVDF flexible piezoelectric pipe can achieve efficient degradation of various pollutants under water flow drive, and can be used for the deep treatment of organic wastewater. It is evident that this invention has wide applications in the field of water purification.

[0040] (6) Gram-negative Escherichia coli was selected as the test bacteria. Before sterilization, all test materials were sterilized at high temperature in an autoclave. The prepared piezoelectric composite material was placed in 50 ml of bacterial suspension. A certain amount of bacterial solution was evenly spread on trypsin agar and cultured at 37°C for 16 h. Quantitative bacterial counting was performed and bacterial density was calculated. The bacterial survival rate was much lower than 0.002‰, indicating that the C3N5 / PVDF piezoelectric composite material has excellent antibacterial properties.

[0041] Example 2:

[0042] The preparation and application of a nitrogen-rich carbide piezoelectric composite material in water purification and antibacterial treatment are described below.

[0043] (1) Weigh 10g of the precursor 3-amino1,2,4-triazole and place it in a covered crucible. Transfer it to a muffle furnace and calcine it at 550℃ for 2 hours in an air atmosphere. The heating rate is 5℃ / min. After holding at the temperature for 4 hours, cool and grind it for later use.

[0044] (2) Weigh 2g of the powder sample obtained in step (1), dissolve 0.36g of NaOH in 80mL of deionized water, and stir continuously until dissolved to obtain a suspension; transfer the suspension to a 100ml polytetrafluoroethylene reactor and react at 120℃ for 18 hours; after the reaction is completed, wash with deionized water and ethanol until the filtrate is transparent and colorless, and dry in an oven at 70℃ for 12 hours to obtain nitrogen-rich carbide C3N5;

[0045] (3) Weigh 3g of polyvinylidene fluoride (PVDF) powder and 0.15g of C3N5 powder prepared in step (2), dissolve them in 30mL of N,N-dimethylformamide solvent, place them in a water bath, stir at 70℃ for 2h until completely dissolved, disperse under ultrasonic conditions for 45min to obtain a uniform piezoelectric polymer base liquid.

[0046] (4) Take 5 ml of the above piezoelectric polymer base liquid and apply it evenly on a clean glass slide. Use a spray bottle containing deionized water to spray deionized water evenly. The liquid solidifies by phase inversion to obtain C3N5 / PVDF-TrFE piezoelectric composite film. Soak the obtained film in water for later use.

[0047] (5) At room temperature, 50 mL of an aqueous solution containing 10 mg / L of organic pollutants was taken, and a C3N5 / PVDF-TrFE piezoelectric composite film was added. The mixture was sonicated at 30 kHz for 40 min. 3 mL of the reaction solution was taken with a syringe every 5 minutes, filtered through a filter membrane, and the concentration of methylene blue was measured. The removal effect is shown in [see figure]. Figure 3 The results show that the C3N5 / PVDF-TrFE piezoelectric composite film can achieve efficient degradation of lomefloxacin, oxytetracycline, and metronidazole under ultrasonic driving.

[0048] (6) Gram-negative Escherichia coli was selected as the test bacteria. Before sterilization, all test materials were sterilized at high temperature in an autoclave. The prepared piezoelectric composite material was placed in 20 ml of bacterial suspension. A certain amount of bacterial solution was evenly spread on trypsin agar and cultured at 37°C for 24 h. Quantitative bacterial counting was performed and bacterial density was calculated. The bacterial survival rate was much lower than 0.015‰, indicating that the C3N5 / PVDF-TrFE piezoelectric composite film has excellent antibacterial properties.

[0049] Example 3:

[0050] The preparation and application of a nitrogen-rich carbide piezoelectric composite material in water purification and antibacterial treatment are described below.

[0051] (1) Weigh 15g of the precursor 3-amino1,2,4-triazole and place it in a covered crucible. Transfer it to a muffle furnace and calcine it at 550℃ for 3 hours in an air atmosphere. The heating rate is 10℃ / min. After holding the temperature for 2 hours, cool and grind it for later use.

[0052] (2) Weigh 8g of the powder sample obtained in step (1), dissolve 3.6g of NaOH in 400mL of deionized water, and stir continuously until dissolved to obtain a suspension; transfer the suspension to a 500ml polytetrafluoroethylene reactor and react at 150℃ for 24 hours; after the reaction is completed, wash with deionized water and ethanol until the filtrate is transparent and colorless, and dry in an oven at 70℃ for 24 hours to obtain nitrogen-rich carbide C3N5;

[0053] (3) Weigh 5g of polyvinylidene fluoride (PVDF) powder and 0.75g of C3N5 powder prepared in step (2), dissolve them in 50mL of N,N-dimethylformamide solvent, place them in a water bath, stir at 70℃ for 3h until completely dissolved, disperse under ultrasonic conditions for 60min, and obtain a uniform piezoelectric polymer base liquid.

[0054] (4) Take 15 ml of the above piezoelectric polymer base liquid, pour it into a small beaker, and use a peristaltic pump to drip deionized water to obtain C3N5 / PVDF-HFP piezoelectric composite microspheres. Wash the obtained microspheres with deionized water and soak them in water for later use.

[0055] (5) At room temperature, place the prepared microspheres into a solution containing 20 mg / L tetracycline contaminants, turn on the stirrer to make the microspheres roll evenly, and measure 3 ml of the reaction solution with a syringe every 5 minutes. After filtration through a filter membrane, determine the concentration of chlortetracycline. The removal effect is shown in [see figure]. Figure 3 The results show that the C3N5 / PVDF-HFP piezoelectric composite microspheres exhibit efficient degradation of norfloxacin and rhodamine B under stirring.

[0056] (6) Gram-negative *Escherichia coli* was selected as the test bacteria. Before sterilization, all test materials were sterilized at high temperature in an autoclave. The prepared piezoelectric composite microspheres were placed in 20 ml of bacterial suspension. A certain amount of bacterial suspension was evenly spread on trypsin agar and incubated at 37°C for 18 h. Quantitative bacterial counting was performed, and bacterial density was calculated. The calculation showed that the bacterial survival rate was far below 0.001‰. (See...) Figure 4 This indicates that the C3N5 / PVDF-HFP piezoelectric composite microspheres have excellent antibacterial properties.

Claims

1. A method for preparing a nitrogen-rich carbide piezoelectric composite material, characterized in that, The specific steps are as follows: (1) 3-amino-1,2,4-triazole is placed in a covered crucible and transferred to a muffle furnace. It is calcined at 500-550℃ for 2-4 hours in an air atmosphere with a heating rate of 5-10℃ / min. After holding at the temperature for 2-5 hours, it is cooled and ground for later use. (2) Dissolve 2-10 g of the powder sample obtained in step (1) in 0.1-1 mol / L NaOH aqueous solution, KOH aqueous solution or ammonia water, and stir continuously until dissolved to obtain a suspension; transfer the suspension to a reaction vessel and react at 120-150 ℃ for 12-24 hours; after the reaction is completed, wash with deionized water and ethanol until the filtrate is transparent and colorless, and dry in an oven at 60-80 ℃ for 12-24 hours to obtain nitrogen-rich carbide C3N5; (3) Weigh 1-5 g of piezoelectric polymer powder and 0.1-1 g of nitrogen-rich carbide C3N5 powder obtained in step (2) at a mass ratio of 10-50:1, dissolve them in 10-50 mL of organic solvent, place them in a water bath, stir at 60-70 °C for 1-3 h until completely dissolved, and disperse under ultrasonic conditions for 30-60 min to obtain a uniform piezoelectric polymer base liquid; (4) Take 10-100 mL of the above piezoelectric polymer base liquid and mix it evenly with deionized water. The liquid is solidified by phase inversion method to obtain different forms of nitrogen-rich carbide piezoelectric composite materials. The mixing method of piezoelectric polymer base liquid and deionized water can be uniform spraying or uniform rotation propulsion in the pipeline. The piezoelectric composite material formed can be thin film, microsphere, or attached to the inner wall of the pipeline to form a piezoelectric composite pipeline.

2. The method for preparing the nitrogen-rich carbide piezoelectric composite material according to claim 1, characterized in that, In step (3), the organic solvent can be any one of N,N-dimethylformamide, N-methylpyrrolidone, or dimethylthionite.

3. The method for preparing the nitrogen-rich carbide piezoelectric composite material according to claim 1, characterized in that, The piezoelectric polymer can be any one of polyvinylidene fluoride, poly(vinylidene fluoride-trifluoroethylene), or poly(vinylidene fluoride-hexafluoropropylene).

4. The application of a nitrogen-rich carbide piezoelectric composite material in the degradation of pollutants, characterized in that, The nitrogen-rich carbide piezoelectric composite material is prepared according to any one of the preparation methods described in claims 1-3. The prepared piezoelectric composite material is added to a pollutant aqueous solution with a volume of 20-200 mL, and the piezoelectric effect is induced by different driving forces. The reaction is carried out for 0.25-1 h. The supernatant is taken, filtered through a filter membrane, and the concentration of the target pollutant is measured. The pollutants include ciprofloxacin hydrochloride, oxytetracycline, ofloxacin, chlortetracycline, tetracycline, methylene blue, and rhodamine B. The driving method is one of water flow, ultrasound, stirring, or ball milling.

5. The application of a nitrogen-rich carbide piezoelectric composite material in antibacterial activity, characterized in that, The nitrogen-rich carbide piezoelectric composite material was prepared according to any one of claims 1-3. The bacterial strain was Gram-negative Escherichia coli. All test materials were sterilized at high temperature in an autoclave. The prepared piezoelectric composite material was placed in 10-100 mL of bacterial suspension. A certain amount of bacterial suspension was evenly spread on trypsin agar and cultured at 37 °C for 16-48 h. Quantitative bacterial counting was performed, and the bacterial density was calculated.

Images