2D / 2D black phosphorus / carbon nitride coated PVDF-HFP and preparation method and application thereof

Abstract

The invention discloses 2D / 2D black phosphorus / carbon nitride-coated PVDF-HFP and a preparation method and application thereof, and belongs to the technical field of water body micropollutant treatment.The preparation method comprises the steps that black phosphorus and carbon nitride are evenly dispersed in an organic solvent A according to the preset adding amount, and centrifugal treatment is conducted to obtain 2D / 2D black phosphorus / carbon nitride; pVDF-HFP powder is uniformly dispersed in an organic solvent B, and a first mixed solution is obtained; uniformly dispersing 2D / 2D black phosphorus / carbon nitride in the first mixed solution to obtain a second mixed solution; coating the second mixed solution on a flat substrate for heat treatment to obtain 2D / 2D black phosphorus / carbon nitride coated PVDF-HFP; the black phosphorus, the carbon nitride and the PVDF-HFP are utilized, and the pollutant treating agent which is good in effect, environmentally friendly and high in efficiency is provided.

Description

Technical Field

[0001] The invention relates to 2D / 2D black phosphorus / carbon nitride@PVDF-HFP and a preparation method and application thereof, belonging to the technical field of water micro-pollutant treatment. Background Art

[0002] Against the backdrop of increasingly severe global environmental problems, water pollution has become a major obstacle to sustainable social development. Persistent organic pollutants, due to their wide variety, strong toxicity and difficulty in degradation, pose a serious threat to the safety of ecosystems and human health. With the acceleration of industrialization and population growth, the discharge of various industrial wastewaters and domestic sewage has increased dramatically, resulting in a significant increase in the concentration of persistent organic pollutants in natural water bodies such as rivers. Therefore, there is an urgent need to develop more efficient and environmentally friendly water environment management technologies.

[0003] Traditional methods for treating micropollutants in water bodies mainly include physical treatment, chemical treatment and biological treatment. Physical treatment such as filtration and sedimentation mainly removes suspended matter and impurities in water bodies, but has limited effect on micropollutants dissolved in water. Chemical treatment can remove some organic micropollutants through oxidation reactions, but may produce new pollutants, easily cause secondary pollution, and require continuous addition of chemical agents. Biological treatment relies on the green metabolic degradation of microorganisms, but the treatment time for persistent organic pollutants that are difficult to degrade is long and the effect is not ideal. Summary of the invention

[0004] The purpose of the present invention is to provide a 2D / 2D black phosphorus / carbon nitride @PVDF-HFP and a preparation method and application thereof, so as to solve the problems of secondary pollution, low efficiency and poor effect existing in the prior art.

[0005] To achieve the above objectives, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP, comprising: Black phosphorus and carbon nitride are uniformly dispersed in an organic solvent A according to a preset addition amount, and subjected to centrifugal treatment to obtain 2D / 2D black phosphorus / carbon nitride; The PVDF-HFP powder is uniformly dispersed in the organic solvent B to obtain a first mixed solution; uniformly dispersing 2D / 2D black phosphorus / carbon nitride in the first mixed solution to obtain a second mixed solution; The second mixed solution is coated on a flat substrate and heat treated to obtain 2D / 2D black phosphorus / carbon nitride@PVDF-HFP.

[0006] Furthermore, the mass ratio of the added amount of the black phosphorus and the carbon nitride is (0.05~0.5):1.

[0007] Furthermore, the step of uniformly dispersing black phosphorus and carbon nitride in a preset amount in an organic solvent A comprises: Black phosphorus and carbon nitride are added into organic solvent A according to a preset amount, and are uniformly dispersed by ultrasonic treatment through liquid phase exfoliation method.

[0008] Furthermore, the organic solvent A is N-methyl-2-pyrrolidone, and the purity of the organic solvent A is 98-99.5%; The organic solvent B is a mixed solvent of N,N-dimethylformamide and acetone, wherein the molar ratio of N,N-dimethylformamide to acetone to acetone is (7-5):4, and the purity of the organic solvent B is 98-99.5%.

[0009] Furthermore, the rotation speed of the centrifugal treatment is 3000-4000 r / min, and the time is 10-20 minutes.

[0010] Further, the PVDF-HFP powder is uniformly dispersed in the organic solvent B by ultrasonic treatment, and the 2D / 2D black phosphorus / carbon nitride is uniformly dispersed in the first mixed solution by ultrasonic treatment; The temperature of the ultrasonic treatment process is 60-80°C and the time is 20-40 minutes.

[0011] Furthermore, the flat substrate is a 1~2 m×1~2 m nickel foam fiber pad; The coating is accomplished by casting / spin coating.

[0012] Further, the heat treatment includes: In an inert gas or reducing gas atmosphere, treat at 150~180 ℃ for 1~2 h.

[0013] In a second aspect, the present invention provides a 2D / 2D black phosphorus / carbon nitride@PVDF-HFP prepared by any method described in the first aspect.

[0014] In the third aspect, the present invention provides an application of 2D / 2D black phosphorus / carbon nitride @PVDF-HFP, in which the 2D / 2D black phosphorus / carbon nitride @PVDF-HFP prepared by any method described in the first aspect is used to degrade persistent organic pollutants in water under the dual effects of solar energy and water flow energy.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: The present invention provides a 2D / 2D black phosphorus / carbon nitride@PVDF-HFP and a preparation method and application thereof. Black phosphorus, carbon nitride and PVDF-HFP are used as main raw materials to prepare a new type of non-metallic composite material, and the unique two-dimensional structure and excellent electrical and optical properties of black phosphorus are utilized. The advantages of carbon nitride, such as simple synthesis, low cost, high stability, non-toxicity, narrow band gap and high light response under visible light, are utilized. The advantages of PVDF-HFP, such as good mechanical strength, chemical stability, electrochemical stability and piezoelectric properties, which can generate a piezoelectric field under the action of water flow (further enhancing the photocatalytic efficiency of the system and extending the service life), are utilized. By combining black phosphorus, carbon nitride and PVDF-HFP, the 2D / 2D heterostructure not only expands the light absorption range, but also provides abundant charge transfer channels, and at the same time enhances the interface contact between materials to promote charge transfer, thereby greatly improving the degradation efficiency of persistent organic pollutants, and the materials used have no secondary pollution risk.

[0016] In addition, on the basis of photocatalytic technology, piezoelectric catalytic technology is combined to utilize solar energy and water flow energy to further promote the separation and transmission of photogenerated carriers, improve the efficiency of photocatalytic reaction, extend the service life of the system, and facilitate its laying in river environment to degrade persistent organic pollutants.

[0017] This photocatalytic-piezoelectric system (utilizing solar energy and water kinetic energy) is simple in material preparation, cost-effective and environmentally friendly. It is suitable for the efficient, green and sustainable removal of difficult-to-degrade persistent organic pollution in natural water bodies such as rivers. There is no risk of metal ion leakage in the water environment, and it makes full use of renewable energy to reduce the pollution of nanoparticles in the water environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of a method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a 2D / 2D black phosphorus / carbon nitride@PVDF-HFP applied to river management provided by an embodiment of the present invention; Figure 3 It is a schematic diagram of monitoring the concentration of persistent organic pollutants (PCBs) before and after 24 hours using black phosphorus / carbon nitride, 2D / 2D black phosphorus / carbon nitride and 2D / 2D black phosphorus / carbon nitride@PVDF-HFP in a simulated river environment provided by an embodiment of the present invention; Figure 4 It is a schematic diagram of concentration monitoring after the degradation of persistent organic pollutants (DDT) by using 2D / 2D black phosphorus / carbon nitride@PVDF-HFP provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0020] In recent years, photocatalytic technology has attracted widespread attention as a green and sustainable means of water environment restoration. However, it still faces some challenges in practical application, such as the need to improve the efficiency of photocatalysts for refractory organic pollutants in water and the difficulty in recycling powdered photocatalysts from water bodies. Therefore, it is necessary to develop new types of efficient photocatalysts that are easy to recycle in order to cope with the increasingly complex pollution of natural water bodies such as rivers.

[0021] Photocatalytic technology uses light energy to excite catalysts to produce free radicals, thereby degrading organic pollutants, while the piezoelectric effect generates electrical signals by applying mechanical stress to promote the reaction of the active sites of the catalyst. The combination of the two can not only enhance the light absorption capacity of the catalyst, but also improve its photocatalytic performance, and is expected to achieve sustainable and efficient removal of persistent organic pollutants in natural water bodies such as rivers.

[0022] Therefore, the present invention specifically solves the problems of the prior art described in the content of the invention through the following embodiments 1 and 2, and verifies the effects of the present invention through specific experiments.

[0023] Example 1.

[0024] like Figure 1 As shown, the present invention provides a method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP, comprising the following steps: Black phosphorus and carbon nitride were uniformly dispersed in N-methyl-2-pyrrolidone (purity 99%) by liquid phase exfoliation ultrasonic treatment (temperature 70 ℃, time 30 minutes) in a certain ratio (mass ratio of 0.05:1), and centrifuged (speed 3500 r / min, time 15 minutes) to obtain 2D / 2D black phosphorus / carbon nitride; PVDF-HFP (vinylidene fluoride-hexafluoropropylene copolymer) powder was uniformly dispersed in N,N-dimethylformamide and acetone (the molar ratio of N,N-dimethylformamide and acetone was 6:4, and the purity of the solvent after mixing was 99%) by ultrasonic treatment (temperature 70 ℃, time 35 minutes), and then 2D / 2D black phosphorus / carbon nitride was added, and ultrasonic treatment was performed again (temperature 70 ℃, time 30 minutes). The obtained uniform mixed solution was coated on a 1.5 m×1.5 m nickel foam fiber pad by a casting method and heat treated (inert gas, temperature 160 ℃, time 1.5 h), and 2D / 2D black phosphorus / carbon nitride@PVDF-HFP was obtained.

[0025] Example 2.

[0026] like Figure 1As shown, the present invention provides a method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP, comprising the following steps: Black phosphorus and carbon nitride were uniformly dispersed in N-methyl-2-pyrrolidone (purity 99%) by liquid phase exfoliation ultrasonic treatment (temperature 70 ℃, time 30 minutes) in a certain ratio (mass ratio of 0.1:1), and centrifuged (speed 3500 r / min, time 15 minutes) to obtain 2D / 2D black phosphorus / carbon nitride; PVDF-HFP powder was uniformly dispersed in N,N-dimethylformamide and acetone (the molar ratio of N,N-dimethylformamide and acetone was 6:4, and the purity of the mixed solvent was 99%) by ultrasonic treatment (temperature 70 ℃, time 35 minutes), and then 2D / 2D black phosphorus / carbon nitride was added, and ultrasonic treatment was performed again (temperature 70 ℃, time 30 minutes). The obtained uniform mixed solution was coated on a 2 m×2 m nickel foam fiber pad by a casting method and heat treated (inert gas, temperature 160 ℃, time 1.5 h), and 2D / 2D black phosphorus / carbon nitride@PVDF-HFP was obtained.

[0027] like Figure 2 As shown, the prepared 2D / 2D black phosphorus / carbon nitride@PVDF-HFP was applied to river management, and the following simulation tests were carried out: The 2D / 2D black phosphorus / carbon nitride@PVDF-HFP and black phosphorus / carbon nitride and 2D / 2D black phosphorus / carbon nitride prepared in Example 1 were applied to the treatment of persistent organic pollutants polychlorinated biphenyls in a simulated river environment. Figure 3 As shown in the figure, the concentration changes of polychlorinated biphenyls under the action of different materials were monitored within 24 hours. The results showed that the degradation rate of 2D / 2D black phosphorus / carbon nitride@PVDF-HFP was increased by 47% compared with black phosphorus / carbon nitride materials, and increased by 26% compared with 2D / 2D black phosphorus / carbon nitride, indicating that the 2D / 2D black phosphorus / carbon nitride@PVDF-HFP composite material has a significant degradation effect on polychlorinated biphenyls, a persistent organic pollutant in rivers.

[0028] The 2D / 2D black phosphorus / carbon nitride @PVDF-HFP prepared in Example 2 was applied to the treatment of the persistent organic pollutant DDT in a simulated river environment. Figure 4 As shown in the figure, the concentration changes of DDT under the action of different materials were monitored within 24 hours. The results showed that the degradation rate of DDT by 2D / 2D black phosphorus / carbon nitride@PVDF-HFP reached 77% within 16 hours, and the degradation rate within 24 hours could be as high as 85%.

[0029] In summary, 2D / 2D black phosphorus / carbon nitride@PVDF-HFP exhibits high degradation efficiency and good stability in the degradation of persistent organic pollutants.

[0030] In the chemical formula: @ means load, the content after @ is the carrier, and / means compound.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing 2D / 2D black phosphorus / carbon nitride @PVDF-HFP, characterized in that: include: Black phosphorus and carbon nitride are uniformly dispersed in an organic solvent A according to a preset addition amount, and subjected to centrifugal treatment to obtain 2D / 2D black phosphorus / carbon nitride; Evenly dispersing PVDF-HFP powder in organic solvent B to obtain a first mixed solution; uniformly dispersing 2D / 2D black phosphorus / carbon nitride in the first mixed solution to obtain a second mixed solution; The second mixed solution is coated on a flat substrate and heat treated to obtain 2D / 2D black phosphorus / carbon nitride@PVDF-HFP.

2. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The mass ratio of the added amount of the black phosphorus and the carbon nitride is (0.05~0.5):

1.

3. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The method of uniformly dispersing black phosphorus and carbon nitride in an organic solvent A according to a preset addition amount comprises: Black phosphorus and carbon nitride are added into organic solvent A according to a preset amount, and are uniformly dispersed by ultrasonic treatment through liquid phase exfoliation method.

4. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The organic solvent A is N-methyl-2-pyrrolidone, and the purity of the organic solvent A is 98-99.5%; The organic solvent B is a mixed solvent of N,N-dimethylformamide and acetone, wherein the molar ratio of N,N-dimethylformamide to acetone to acetone is (7-5):4, and the purity of the organic solvent B is 98-99.5%.

5. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The rotation speed of the centrifugal treatment is 3000-4000 r / min, and the time is 10-20 minutes.

6. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The PVDF-HFP powder is uniformly dispersed in the organic solvent B by ultrasonic treatment, and the 2D / 2D black phosphorus / carbon nitride is uniformly dispersed in the first mixed solution by ultrasonic treatment; The temperature of the ultrasonic treatment process is 60-80°C and the time is 20-40 minutes.

7. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The flat base is a 1~2 m×1~2 m nickel foam fiber pad; The coating is accomplished by casting / spin coating.

8. The method for preparing 2D / 2D black phosphorus / carbon nitride@PVDF-HFP according to claim 1, characterized in that: The heat treatment comprises: In an inert gas or reducing gas atmosphere, treat at 150~180 ℃ for 1~2 h.

9. A 2D / 2D black phosphorus / carbon nitride@PVDF-HFP, characterized in that: Prepared by the method according to any one of claims 1 to 8.

10. An application of 2D / 2D black phosphorus / carbon nitride @PVDF-HFP, characterized in that: The 2D / 2D black phosphorus / carbon nitride@PVDF-HFP prepared by the method described in any one of claims 1 to 8 is used to degrade persistent organic pollutants in water under the dual effects of solar energy and water flow energy.

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