Piezoelectric effect excitation method and application thereof

Abstract

The invention discloses a piezoelectric effect excitation method and application thereof. The piezoelectric effect of piezoelectric catalytic material particles is excited by applying mechanical stress to the piezoelectric catalytic material particles through rotational flow oscillation. According to the piezoelectric effect excitation method provided by the invention, the piezoelectric effect of the piezoelectric catalytic material is excited by adopting rotational flow oscillation, the excitation effect on the piezoelectric effect of the piezoelectric catalytic material particles in the rotational flow field can be realized through relatively low energy input, and no matter how large the reactor exists, the piezoelectric effect can be excited. All the piezoelectric catalytic particles in the rotational flow field can be subjected to large rotational flow oscillation mechanical stress, so that the piezoelectric effect of the piezoelectric catalytic material particles in the rotational flow field in the reactor can be effectively excited, the catalytic efficiency of the piezoelectric catalytic material particles is improved, and a foundation is laid for large-scale application of piezoelectric catalytic materials.

Description

Technical Field

[0001] The invention belongs to the field of piezoelectric technology, and in particular relates to a piezoelectric effect excitation method and application thereof. Background Art

[0002] The piezoelectric effect is a phenomenon widely used in sensors, energy harvesters, and acoustic equipment. It is mainly manifested in that piezoelectric materials generate electric charges when subjected to external mechanical stress (positive piezoelectric effect), or undergo mechanical deformation when an electric field is applied (inverse piezoelectric effect). With the advancement of science and technology, the application field of the piezoelectric effect has been further expanded, and it has unique advantages in the fields of wastewater degradation treatment and water decomposition to produce hydrogen. Piezoelectric catalytic technology can realize the conversion of mechanical energy into electrical energy or chemical energy to drive chemical reactions during the reaction process. For example, under the tensile and compressive effects of periodic mechanical stress, the positive and negative polarized charges generated on the surface of the piezoelectric material can effectively enhance the activity of the catalyst in pollutant degradation and improve the degradation efficiency of pollutants. In addition, in the process of water decomposition to produce hydrogen, the charge generated by the piezoelectric effect can also increase the yield of hydrogen and realize the conversion of mechanical energy into clean energy such as hydrogen. In general, piezoelectric catalytic technology is considered to be a new technology that can solve energy problems and the environment.

[0003] The deformation of piezoelectric materials to generate polarization electric fields and then the piezoelectric catalytic process always requires external mechanical stress. At present, the different stress sources for inducing piezoelectric catalysis mainly include: ultrasound, stirring, ball milling and pressure cantilever devices. Among them, ultrasonic vibration is one of the most common and widely used methods of inducing piezoelectric effect in the laboratory. Although ultrasonic excitation of piezoelectric effect has a good effect, from the perspective of energy consumption, ultrasonic equipment requires a higher energy input to generate sufficient mechanical stress. In particular, the range of ultrasonic action is limited and is not suitable for large-scale reactions or occasions that require uniform stress distribution. Therefore, the development of a new method for exciting piezoelectric effect with the potential for large-scale implementation to replace ultrasonic oscillation excitation of piezoelectricity is of great significance for the large-scale promotion of piezoelectric materials in industrial applications. Summary of the invention

[0004] In order to solve the problem that piezoelectric materials are difficult to promote on a large scale in industrial applications, the present invention provides a piezoelectric effect excitation method and application thereof.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A first aspect of the present invention is to provide a method for stimulating the piezoelectric effect by applying mechanical stress to piezoelectric catalytic material particles through swirl oscillation.

[0007] Furthermore, the swirl oscillation is generated by a strong spiral flow reactor.

[0008] Furthermore, the piezoelectric effect excitation method specifically includes the following steps:

[0009] S1. Dispersing the piezoelectric catalytic material particles in a first solution to form a mixed system of the piezoelectric catalytic material particles and the first solution;

[0010] S2. Controlling the first solution in which the piezoelectric catalytic material particles are dispersed to enter a strong helical flow reactor at a high first tangential velocity, so that a strong three-dimensional rotational flow field is formed in the strong helical flow reactor. The piezoelectric catalytic material particles perform a following rotational motion along with the rotation of the three-dimensional rotational flow field. During the motion, the piezoelectric catalytic material particles are deformed under the action of the swirling oscillation mechanical stress, generating surface charges;

[0011] S3. Under the action of the continuous mechanical stress, the charges inside the piezoelectric catalytic material particles accumulate on the surface area of the piezoelectric catalytic material particles;

[0012] S4. The charges accumulated on the surface area of the piezoelectric catalytic material particles are transferred in the first solution, generating a catalytically active substance, which further participates in a chemical reaction.

[0013] Dispersing piezoelectric catalytic material particles in a liquid phase provides an environment conducive to charge separation, migration, and reaction, enabling effective utilization of the piezoelectric effect of piezoelectric catalytic particles for catalytic reactions. The first solution containing dispersed piezoelectric catalytic material particles is introduced into a strong helical flow reactor at a high speed in a tangential direction, generating a strong three-dimensional rotating flow field within the reactor. Under the action of this flow field, the piezoelectric catalytic materials entering the reactor are first evenly dispersed, reducing the aggregation of piezoelectric catalytic material particles during the reaction process. Due to the good followability of piezoelectric catalytic material particles in the liquid phase, they can follow the rotation of the three-dimensional swirling flow field within the strong helical flow reactor. Therefore, the piezoelectric catalytic material particles in the strong helical flow reactor are subjected to the combined action of forces such as gravity, fluid drag force, buoyancy force, and centrifugal force, resulting in deformation of the piezoelectric catalytic material particles and thus generating surface charges. In particular, during the process of the piezoelectric catalytic material particles following the rotational motion, they are subjected to an unbalanced shear stress on the surface, causing the piezoelectric catalytic material particles to rotate at a high speed around their own axes and revolve around the center of the reactor within the strong helical flow reactor. Under the coupled centrifugal action of this high-speed rotation around the axis and revolution, periodic swirling oscillations are generated, further enhancing the deformation of the piezoelectric catalytic material particles and thus generating more surface charges. The piezoelectric catalytic material particles follow the rotation of the three-dimensional rotating flow field in a helical following motion, and during the entire motion process, they are subjected to the action of swirling oscillations, that is, the piezoelectric catalytic material particles are continuously subjected to swirling oscillation mechanical stress, resulting in deformation. This deformation causes the electric dipoles inside the piezoelectric catalytic material particles to rearrange, resulting in the generation of charges at both ends of the material. Under the action of the continuous mechanical stress, the charges inside the piezoelectric catalytic material particles accumulate on their surface, forming a potential difference. Under the action of the potential difference, the charges on the surface of the piezoelectric catalytic material particles interact with water and other reactants in the liquid phase, generating active substances such as hydroxyl radicals and superoxide radicals, which further participate in chemical reactions.

[0014] Further, in the step S2, the first tangential velocity is 1 - 8 m / s.

[0015] When the tangential flow velocity of the first solution entering the strong helical flow reactor is lower than 1 m / s, the three-dimensional rotating flow field formed within the strong helical flow reactor cannot provide sufficient swirling oscillation mechanical stress for the piezoelectric catalytic material particles in the flow field, and thus cannot effectively stimulate the piezoelectric effect of the piezoelectric catalytic material particles. When the tangential flow velocity of the first solution entering the strong helical flow reactor is higher than 8 m / s, it will result in an excessive swirling oscillation mechanical stress applied to the surface of the piezoelectric catalytic particle material, causing mechanical fatigue due to overexcitation, damaging the integrity of its structure, and reducing the catalytic activity.

[0016] Further, the strong helical flow reactor is a cylindrical reactor, and the top of the cylindrical reactor is provided with a first tangential inlet, and the bottom is provided with a first outlet.

[0017] Furthermore, the cylindrical reactor is configured with a power device for controlling the tangential velocity of the first solution at the first tangential inlet to be at a first tangential velocity.

[0018] A power device for controlling the fluid velocity at the inlet of the strong spiral flow reactor is added. When the tangential velocity of the fluid at the first tangential inlet is low and the three-dimensional rotating flow field formed in the strong spiral flow reactor is not sufficient to excite the piezoelectric effect of the piezoelectric catalytic material particles or when the three-dimensional rotating flow field in the strong spiral flow reactor needs to be regulated, the tangential velocity of the fluid at the first tangential inlet can be regulated by the power device to achieve the adjustment of the frequency and intensity of the swirl oscillation, thereby realizing the control and optimization of the piezoelectric effect.

[0019] Furthermore, the first outlet is a tangential outlet.

[0020] Furthermore, the piezoelectric catalytic material is one or more of barium titanate, zinc oxide, zinc sulfide, titanium oxide, lithium tantalate, strontium titanate, bismuth ferrite, molybdenum sulfide, lead zirconate titanate, C3N4.

[0021] Furthermore, when the piezoelectric catalytic material is molybdenum sulfide, the first tangential velocity is 6.6 m / s; when the piezoelectric catalytic material is zinc oxide, the first tangential velocity is 5.5 m / s.

[0022] For a piezoelectric catalytic material, when the resonant frequency of the piezoelectric catalytic material matches the driving frequency provided by the swirl oscillation, the material will produce a resonance effect. The mechanical stress on the surface of the piezoelectric catalytic material particles can be transmitted to its interior with the highest efficiency and excite the strongest piezoelectric effect. This resonance effect not only enhances the catalytic activity of the material but also improves the selectivity and rate of the catalytic reaction. When the piezoelectric catalytic material particles are molybdenum sulfide particles, when the tangential velocity of the first solution at the first tangential inlet is 6.6 m / s, the frequency of the swirl oscillation received by the surface of the molybdenum sulfide particles matches the resonant frequency of the material, and the strongest piezoelectric effect can be excited; similarly, when the piezoelectric catalytic material particles are zinc oxide particles, when the tangential velocity of the first solution at the first tangential inlet is 5.5 m / s, the frequency of the swirl oscillation received by the surface of the zinc oxide particles matches the resonant frequency of the material, and the strongest piezoelectric effect can be excited.

[0023] The second aspect of the present invention lies in providing an application of the above piezoelectric effect excitation method in the field of wastewater treatment.

[0024] Compared with the prior art, the present invention has at least the following beneficial effects:

[0025] 1. In the existing field of piezoelectric catalysis technology, the piezoelectric effect of piezoelectric catalytic materials is excited by ultrasonic oscillation. Ultrasonic devices often require a high energy input to generate sufficient mechanical stress to excite the piezoelectric effect of piezoelectric catalytic materials. Moreover, the range of ultrasonic wave action is limited and is not suitable for large-scale reactions or occasions that require a uniform stress distribution. When the reactor is large, due to the attenuation of ultrasonic waves during the reaction process, it is impossible to continuously provide sufficient mechanical stress to all piezoelectric catalytic material particles inside the reactor at a high intensity, and thus it is impossible to effectively excite the piezoelectric effect of all piezoelectric catalytic material particles inside the reactor, resulting in a low catalytic efficiency inside the reactor and indirectly making it difficult for piezoelectric catalytic materials to achieve large-scale industrial applications. The piezoelectric effect excitation method provided by the present invention uses swirl oscillation to excite the piezoelectric effect of piezoelectric catalytic materials. Through a low energy input, the excitation effect on the piezoelectric effect of piezoelectric catalytic material particles in the swirl field can be achieved. Moreover, regardless of the size of the reactor, all piezoelectric catalytic particles located in the swirl flow field can be subjected to a large swirl oscillation mechanical stress, so that the piezoelectric effect of the piezoelectric catalytic material particles located in the swirl field inside the reactor can be effectively excited, improving its catalytic efficiency and laying a foundation for the large-scale application of piezoelectric catalytic materials.

[0026] 2. The piezoelectric effect excitation method of the present invention uses swirl oscillation to replace ultrasonic oscillation to excite the piezoelectric effect, solves the challenge that it is difficult to achieve large-scale industrial applications by traditional ultrasonic oscillation to excite the piezoelectric effect, and overcomes the disadvantages of low energy transfer efficiency and uneven mechanical stress distribution of ultrasonic oscillation.

[0027] 3. The piezoelectric effect excitation method of the present invention uses swirl oscillation to replace ultrasonic oscillation to excite the piezoelectric effect, avoiding the high energy consumption requirements of maintaining high power and high frequency of ultrasonic waves throughout the reaction process when using ultrasonic oscillation to excite the piezoelectric effect, and providing a guarantee for the low energy consumption and high efficiency requirements in the large-scale industrial application of the piezoelectric effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the strong spiral flow reactor in Embodiment 1 of the present invention.

[0029] Figure 2 It is a schematic diagram of the swirl piezoelectric reaction device in Embodiment 1 of the present invention.

[0030] Figure 3 It is a comparison diagram of the effects of swirl oscillation excitation of nanosheet flower MoS2 for degradation of phenol wastewater and static state nanosheet flower MoS2 for degradation of phenol wastewater in Embodiment 1 of the present invention and Comparative Example 1.

[0031] Figure 4This is a comparison diagram of the effect of the cyclone oscillation-excited nanorod ZnO in Example 10 of the present invention on the degradation of Acid Orange 7 in dye wastewater and the static-state nanorod ZnO in Comparative Example 2 on the degradation of Acid Orange 7 in dye wastewater.

[0032] Figure 5 This is the degradation effect diagram of phenol in the degradation of phenol wastewater by the cyclone oscillation-excited nanosheet flower MoS2 of the present invention at different flow field velocities.

[0033] Figure 6 This is the degradation effect diagram of Acid Orange 7 in the degradation of Acid Orange 7 in dye wastewater by the cyclone oscillation-excited nanorod ZnO of the present invention at different flow field velocities.

[0034] In the figure: 10 - liquid storage tank; 11 - first reflux port; 12 - first liquid outlet;

[0035] 20 - centrifugal pump;

[0036] 30 - strong spiral flow reactor; 31 - first tangential inlet; 32 - first tangential outlet;

[0037] 41 - first pipeline; 42 - second pipeline. Detailed implementation manners

[0038] The present invention will be further described below in conjunction with specific embodiments. However, it should be understood that these embodiments are only used to illustrate the present invention and do not constitute a limitation to the scope of the present invention.

[0039] The test methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by the manufacturer. Unless otherwise specified, all percentages and parts are by weight.

[0040] I. Regarding the advantages of cyclone oscillation compared with ultrasonic oscillation

[0041] The advantage of cyclone oscillation compared with ultrasonic oscillation is that it is difficult to scale up the industrial process with ultrasonic oscillation. By using cyclone oscillation to excite the piezoelectric effect of piezoelectric catalytic materials, the piezoelectric effect of piezoelectric catalytic material particles in the cyclone field can be excited with a lower energy input. And no matter how large the reactor is, all piezoelectric catalytic particles located in the cyclone flow field can be subjected to a large mechanical stress of cyclone oscillation, so that the piezoelectric effect of the piezoelectric catalytic material particles located in the cyclone field in the reactor can be effectively excited, improving its catalytic efficiency, which lays a foundation for the large-scale application of piezoelectric catalytic materials.

[0042] The inventor first conducted a 50-ml laboratory-scale experiment, and then, based on this system, scaled up the ultrasonic piezoelectric system and the cyclone piezoelectric system to 10 L, 20 L, 50 L, and 100 L respectively. The piezoelectric catalytic material particles used in the experiment were nanosheet flower MoS2 with a concentration of 1.5 g / L; the pollutant was phenol wastewater with a concentration of 20 ppm.

[0043] a. Laboratory-scale experiment: 50-ml ultrasonic piezoelectric reactor

[0044] Frequency: 40 kHz; Power: 300 W;

[0045] Using this system to stimulate nanosheet flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0046] After 2 hours of reaction, in the 50-ml ultrasonic piezoelectric reactor, the degradation rate of 20-ppm phenol wastewater as the pollutant was 33%, and the energy consumption was 0.30 kwh; see Table 1.

[0047] Table 1. Ultrasonic excitation of piezoelectric degradation of pollutants in the laboratory-scale experiment system

[0048]

[0049]

[0050] b. Scaling up of the ultrasonic piezoelectric system:

[0051] 10-L ultrasonic piezoelectric reactor

[0052] Frequency: 40 kHz; Power: 360 W;

[0053] Using this system to stimulate nanosheet flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0054] After 2 hours of reaction, in the 10-L ultrasonic piezoelectric reactor, the degradation rate of 20-ppm phenol wastewater as the pollutant was 4%, and the energy consumption was 0.36 kwh; see Table 2.

[0055] 20-L ultrasonic piezoelectric reactor

[0056] Frequency: 40 kHz; Power: 360 W;

[0057] Using this system to stimulate nanosheet flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0058] After 2 hours of reaction, in the 20-L ultrasonic piezoelectric reactor, the degradation rate of 20-ppm phenol wastewater as the pollutant was 3%, and the energy consumption was 0.36 kwh; see Table 2.

[0059] 50-L ultrasonic piezoelectric reactor

[0060] Frequency: 40 kHz; Power: 360 W;

[0061] Using this system to stimulate nanoflake flower MoS₂ to degrade phenol wastewater with a concentration of 20 ppm;

[0062] After 2 h of reaction, in a 50 L ultrasonic piezoelectric reactor, the degradation rate of 20 ppm phenol wastewater as the pollutant is 1%, and the energy consumption is 0.36 kwh; see Table 2.

[0063] 100 L ultrasonic piezoelectric reactor

[0064] Frequency: 40 kHz; Power: 360 W;

[0065] Using this system to stimulate nanoflake flower MoS₂ to degrade phenol wastewater with a concentration of 20 ppm;

[0066] After 2 h of reaction, in a 100 L ultrasonic piezoelectric reactor, the degradation rate of 20 ppm phenol wastewater as the pollutant is 0.5%, and the energy consumption is 0.36 kwh; see Table 2.

[0067] Table 2. Degradation of pollutants by piezoelectricity stimulated by different ultrasonic amplification systems

[0068]

[0069] c. Amplification of the swirling piezoelectric reaction system

[0070] The swirling piezoelectric reaction device used is as Figure 2 shown. The swirling piezoelectric reaction device includes a liquid storage tank 10, a centrifugal pump 20, and a strong spiral flow reactor 30;

[0071] The top of the strong spiral flow reactor is provided with a first tangential inlet 31, and the bottom is provided with a first tangential outlet 32;

[0072] The top of the liquid storage tank 10 is provided with a first reflux port 11, and the bottom is provided with a first liquid outlet 12;

[0073] The first liquid outlet 12 is connected to the first tangential inlet 31 through a first pipeline 41, the first tangential outlet 32 is connected to the first reflux port 11 through a second pipeline 42, and the centrifugal pump 20 is arranged on the first pipeline 41 to provide power for the fluid entering the strong spiral flow reactor 30 and control the tangential velocity when it enters the strong spiral flow reactor 30.

[0074] Figure 1 is a schematic diagram of the strong spiral flow reactor, and the dotted line in the figure is the strong spiral flow.

[0075] Different swirling piezoelectric systems correspond to strong spiral flow reactors 30 with different volumes. For example, the 10 L swirling piezoelectric reaction system corresponds to a 10 L strong spiral flow reactor; the energy consumption of each swirling piezoelectric system is controlled to be 0.32 kwh for 2 h;

[0076] 10L Swirling Piezoelectric Reaction Device

[0077] Using this system to stimulate nanoflake flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0078] After 2 hours of reaction, in a 10L ultrasonic piezoelectric reactor, the degradation rate of 20 ppm phenol wastewater as the pollutant is 34%; see Table 3.

[0079] 20L Swirling Piezoelectric Reaction Device

[0080] Using this system to stimulate nanoflake flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0081] After 2 hours of reaction, in a 20L ultrasonic piezoelectric reactor, the degradation rate of 20 ppm phenol wastewater as the pollutant is 35%; see Table 3.

[0082] 50L Swirling Piezoelectric Reaction Device

[0083] Using this system to stimulate nanoflake flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0084] After 2 hours of reaction, in a 50L ultrasonic piezoelectric reactor, the degradation rate of 20 ppm phenol wastewater as the pollutant is 26%; see Table 3.

[0085] 100L Swirling Piezoelectric Reaction Device

[0086] Using this system to stimulate nanoflake flower MoS2 to degrade phenol wastewater with a concentration of 20 ppm;

[0087] After 2 hours of reaction, in a 100L ultrasonic piezoelectric reactor, the degradation rate of 20 ppm phenol wastewater as the pollutant is 20%; see Table 3.

[0088] Table 3. Degradation of Pollutants by Piezoelectricity Stimulated by Different Swirling Amplification Systems

[0089]

[0090]

[0091] Comparing the data in Tables 1 - 3, compared with the ultrasonic amplification system, the swirling amplification system has lower energy consumption and higher degradation efficiency. This result fully shows that swirling oscillation can replace ultrasonic oscillation and has the potential to widely stimulate the piezoelectric effect in industrial applications; compared with ultrasonic amplification, swirling oscillation can achieve the degradation of phenol wastewater with low energy consumption and high efficiency.

[0092] II. Degradation of Common Organic Compounds (Phenol, Acid Orange 7) in Wastewater by Piezoelectric Effect Stimulated by Swirling Oscillation

[0093] In the following examples, by controlling the tangential flow velocity (hereinafter referred to as the flow field velocity) of the first solution in which piezoelectric catalytic material particles are dispersed at the inlet of the strong helical flow reactor, the Figure 2 shown swirling piezoelectric reaction device is used to degrade common organic substances (phenol, acid orange 7) in wastewater, and the relationship between the flow field velocity and the piezoelectric effect is studied.

[0094] Example 1

[0095] S11. Dispersed piezoelectric catalytic material particles (nano-sheet flower MoS2, size: 200*300*20 nm, dosage: 72 g) in 20 L of phenol solution (concentration: 20 ppm) to form a mixed system of nano-sheet flower MoS2 and phenol solution;

[0096] S12. Through the centrifugal pump 20, the phenol solution dispersed with nano-sheet flower MoS2 is controlled to enter the strong helical flow reactor 30 at a flow velocity of 6.6 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so that a strong three-dimensional rotating flow field is formed in the strong helical flow reactor 30. The nano-sheet flower MoS2 follows the rotational movement with the rotation of the three-dimensional rotating flow field. During the movement, the nano-sheet flower MoS2 is deformed under the action of the swirling oscillating mechanical stress, generating surface charges;

[0097] S13. Under the action of the continuous swirling oscillating mechanical stress, the charges inside the nano-sheet flower MoS2 accumulate on the surface area of the nano-sheet flower MoS2;

[0098] S14. The charges accumulated on the surface of the nano-sheet flower MoS2 are transferred in the phenol solution, generating active oxidation substances: hydroxyl radicals (·OH) and superoxide radicals (·O2 - ), which react with the phenol in the phenol solution to destroy its molecular structure and degrade the phenol;

[0099] S15. Under the action of the centrifugal pump 20, the phenol solution after the swirling ends immediately returns to the storage tank 10 through the first tangential outlet 31, the second pipeline 42, and the first reflux port 11;

[0100] S16. Repeat the above steps SA2 to SA5 until the whole reaction ends;

[0101] After reacting for 2 h, the degradation efficiency of phenol reaches 30%. The degradation effect of nano-sheet flower MoS2 on phenol within 2 h of reaction is shown in Figure 5 .

[0102] Example 2

[0103] The difference between this example and Example 1 lies in the different flow field velocities, specifically:

[0104] The phenol solution dispersed with nanoflake flower MoS2 is controlled by a centrifugal pump 20 to enter the high-strength helical flow reactor 30 at a flow rate of 1.1 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the high-strength helical flow reactor 30;

[0105] After reacting for 2 h, the degradation efficiency of phenol reaches 12%. During the 2 h of reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown in Figure 5 .

[0106] Example 3

[0107] The difference between this example and Example 1 lies in the different flow field velocities, specifically:

[0108] The phenol solution dispersed with nanoflake flower MoS2 is controlled by a centrifugal pump 20 to enter the high-strength helical flow reactor 30 at a flow rate of 2.2 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the high-strength helical flow reactor 30;

[0109] After reacting for 2 h, the degradation efficiency of phenol reaches 18%. During the 2 h of reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown in Figure 5 .

[0110] Example 4

[0111] The difference between this example and Example 1 lies in the different flow field velocities, specifically:

[0112] The phenol solution dispersed with nanoflake flower MoS2 is controlled by a centrifugal pump 20 to enter the high-strength helical flow reactor 30 at a flow rate of 3.3 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the high-strength helical flow reactor 30;

[0113] After reacting for 2 h, the degradation efficiency of phenol reaches 21%. During the 2 h of reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown in Figure 5 .

[0114] Example 5

[0115] The difference between this example and Example 1 lies in the different flow field velocities, specifically:

[0116] The phenol solution dispersed with nanoflake flower MoS2 is controlled by a centrifugal pump 20 to enter the high-strength helical flow reactor 30 at a flow rate of 4.4 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the high-strength helical flow reactor 30;

[0117] After reacting for 2 h, the degradation efficiency of phenol reaches 22%. During the 2 h of reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown inFigure 5 。

[0118] Example 6

[0119] The difference between this example and Example 1 lies in the flow field velocity, specifically:

[0120] The phenol solution dispersed with nanoflake flower MoS2 is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow rate of 5.5 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0121] React for 2 h, and the degradation efficiency of phenol reaches 26%. Within 2 h of the reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown in Figure 5 。

[0122] Example 7

[0123] The difference between this example and Example 1 lies in the flow field velocity, specifically:

[0124] The phenol solution dispersed with nanoflake flower MoS2 is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow rate of 7.7 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0125] React for 2 h, and the degradation efficiency of phenol reaches 28%. Within 2 h of the reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown in Figure 5 。

[0126] Example 8

[0127] The difference between this example and Example 1 lies in the flow field velocity, specifically:

[0128] The phenol solution dispersed with nanoflake flower MoS2 is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow rate of 8.8 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0129] React for 2 h, and the degradation efficiency of phenol reaches 27%. Within 2 h of the reaction, the degradation effect of nanoflake flower MoS2 on phenol is shown in Figure 5 。

[0130] Example 9

[0131] The difference between this example and Example 1 lies in the flow field velocity, specifically:

[0132] The phenol solution dispersed with nanosheet flower MoS2 is controlled by a centrifugal pump 20 to enter the high-strength helical flow reactor 30 at a flow rate of 9.9 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the high-strength helical flow reactor 30;

[0133] After reacting for 2 h, the degradation efficiency of phenol reaches 27%. Within 2 h of the reaction, the degradation effect of nanosheet flower MoS2 on phenol is shown in Figure 5 .

[0134] Example 10, Degradation of Acid Orange 7 by Swirling Oscillation Exciting Nanorod ZnO

[0135] S101: Dispersed piezoelectric catalytic material particles (nanorod ZnO, average length 4 μm, dosage: 50 g) in 30 L of dye wastewater (concentration of Acid Orange 7: 20 mg / L) to form a mixed system of nanorod ZnO and dye wastewater;

[0136] S102: The dye wastewater dispersed with nanorod ZnO is controlled by a centrifugal pump 20 to enter the high-strength helical flow reactor 30 at a flow rate of 5.5 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the high-strength helical flow reactor 30. The nanorod ZnO follows the rotating motion with the rotation of the three-dimensional rotating flow field. During the motion, the nanorod ZnO is deformed under the action of the swirling oscillation mechanical stress to generate surface charges;

[0137] S103: Under the action of the continuous swirling oscillation mechanical stress, the charges inside the nanorod ZnO accumulate on the surface area of the nanorod ZnO;

[0138] S104: The charges accumulated on the surface area of the nanorod ZnO are transferred in the dye wastewater to generate active oxidation substances: hydroxyl radicals (·OH) and superoxide radicals (·O2 - ), which react with Acid Orange 7 in the dye wastewater to destroy its molecular structure and degrade Acid Orange 7;

[0139] S105: Under the action of the centrifugal pump 20, the dye wastewater after the swirling ends immediately returns to the storage tank 10 through the first tangential outlet 31, the second pipeline 42, and the first return port 11;

[0140] S106: Repeat the above steps S102 - S105 until the whole reaction ends;

[0141] After reacting for 2 h, the degradation efficiency of Acid Orange 7 reaches 28%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0142] Example 11

[0143] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0144] The dye wastewater dispersed with nanorod ZnO is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 1.1 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0145] React for 2 h, and the degradation efficiency of Acid Orange 7 reaches 11%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0146] Example 12

[0147] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0148] The dye wastewater dispersed with nanorod ZnO is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 2.2 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0149] React for 2 h, and the degradation efficiency of Acid Orange 7 reaches 16%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0150] Example 13

[0151] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0152] The dye wastewater dispersed with nanorod ZnO is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 3.3 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0153] React for 2 h, and the degradation efficiency of Acid Orange 7 reaches 20%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0154] Example 14

[0155] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0156] The dye wastewater dispersed with nanorod ZnO is controlled by the centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 4.4 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0157] After reacting for 2 h, the degradation efficiency of Acid Orange 7 reached 24%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0158] Example 15

[0159] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0160] The dye wastewater dispersed with nanorod ZnO is controlled by a centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 6.6 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0161] After reacting for 2 h, the degradation efficiency of Acid Orange 7 reached 26%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0162] Example 16

[0163] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0164] The dye wastewater dispersed with nanorod ZnO is controlled by a centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 7.7 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0165] After reacting for 2 h, the degradation efficiency of Acid Orange 7 reached 26%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0166] Example 17

[0167] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0168] The dye wastewater dispersed with nanorod ZnO is controlled by a centrifugal pump 20 to enter the strong spiral flow reactor 30 at a flow velocity of 8.8 m / s in the tangential direction through the first tangential inlet 31 at a high speed, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0169] After reacting for 2 h, the degradation efficiency of Acid Orange 7 reached 26%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0170] Example 18

[0171] The difference between this example and Example 10 lies in the flow field velocity, specifically:

[0172] The dye wastewater dispersed with nanorod ZnO is controlled by a centrifugal pump 20 to enter the strong spiral flow reactor 30 at a high speed of 9.9 m / s in the tangential direction along the first tangential inlet 31, so as to form a strong three-dimensional rotating flow field in the strong spiral flow reactor 30;

[0173] After reacting for 2 h, the degradation efficiency of Acid Orange 7 reaches 25%. Within 2 h of the reaction, the degradation effect of nanorod ZnO on Acid Orange 7 is shown in Figure 6 .

[0174] Comparative Example 1: Degradation of phenol by nanosheet flower MoS2 under static state

[0175] Piezoelectric catalytic material particles (nanosheet flower MoS2, size: 200*300*20 nm, dosage: 72 g) are dispersed in 20 L of phenol solution (concentration: 20 ppm) to form a mixed system of nanosheet flower MoS2 and phenol solution. After standing for 2 h, the degradation efficiency of phenol is 0.

[0176] Comparative Example 2: Degradation of Acid Orange 7 by nanorod ZnO under static state

[0177] Piezoelectric catalytic material particles (nanorod ZnO, average length 4 μm, dosage: 50 g) are dispersed in 30 L of dye wastewater (concentration of Acid Orange 7: 20 mg / L) to form a mixed system of nanorod ZnO and dye wastewater. After standing for 2 h, the degradation efficiency of Acid Orange 7 is 0.

[0178] Figure 3 This is a comparison diagram of the effect of vortex oscillation excitation of nanosheet flower MoS2 on the degradation of phenol wastewater in Example 1 of the present invention and the degradation of phenol wastewater by nanosheet flower MoS2 under static state in Comparative Example 1. From Figure 3 it can be seen that under the static state, nanosheet flower MoS2 has no degradation effect on phenol; the phenol solution dispersed with nanosheet flower MoS2 is introduced tangentially into the strong spiral flow reactor to form a three-dimensional rotating flow field, and the piezoelectric effect of nanosheet flower MoS2 is excited by vortex oscillation to degrade phenol. When the inlet flow rate is 6.6 m / s, the vortex oscillation can well excite the piezoelectric effect of nanosheet flower MoS2 to degrade phenol.

[0179] Figure 4 This is a comparison diagram of the effect of vortex oscillation excitation of nanorod ZnO on the degradation of Acid Orange 7 in dye wastewater in Example 10 of the present invention and the degradation of Acid Orange 7 in dye wastewater by nanorod ZnO under static state in Comparative Example 2. From Figure 4It can be seen that under the static state, nanorod ZnO has no degradation effect on Acid Orange 7; the dye wastewater dispersed with nanorod ZnO is tangentially introduced into a strong helical flow reactor to form a three-dimensional rotating flow field, and the piezoelectric effect of nanorod ZnO is excited by swirl oscillation to degrade Acid Orange 7 in the dye wastewater. When the inlet flow rate is 5.5 m / s, the swirl oscillation can well excite the piezoelectric effect of nanorod ZnO to degrade Acid Orange 7 in the dye wastewater.

[0180] Figure 5 This is the degradation effect diagram of phenol in the degradation of phenol wastewater by swirl oscillation excited nanosheet flower MoS2 of the present invention at different flow field flow rates. From Figure 5 It can be seen that through flow field regulation (regulating the flow field velocity), the regulation of the swirl oscillation frequency and intensity can be realized, and then the control and optimization of the piezoelectric effect of nanosheet flower MoS2 can be achieved; by comparing the effects of nanosheet flower MoS2 degrading phenol when the flow field velocity of Examples 1-9 increases from 1.1 m / s to 9.9 m / s, it can be seen that the degradation ability of nanosheet flower MoS2 to phenol first increases and then decreases with the increase of the flow field velocity. When the flow field velocity is 6.6 m / s, the degradation ability of nanosheet flower MoS2 to phenol is the strongest, that is, when the flow field velocity is 6.6 m / s, the frequency of the swirl oscillation on the surface of nanosheet flower MoS2 matches the resonance frequency of this nanosheet flower MoS2, and the strongest piezoelectric effect can be excited.

[0181] Figure 6 This is the degradation effect diagram of Acid Orange 7 in the degradation of Acid Orange 7 in dye wastewater by swirl oscillation excited nanorod ZnO of the present invention at different flow field flow rates. From Figure 6 It can be seen that through flow field regulation (regulating the flow field velocity), the regulation of the swirl oscillation frequency and intensity can be realized, and then the control and optimization of the piezoelectric effect of nanorod ZnO can be achieved; by comparing the effects of nanorod ZnO degrading Acid Orange 7 in dye wastewater when the flow field velocity of Examples 10-18 increases from 1.1 m / s to 9.9 m / s, it can be seen that the degradation ability of nanorod ZnO to Acid Orange 7 in dye wastewater first increases and then decreases with the increase of the flow field velocity. When the flow field velocity is 5.5 m / s, the degradation ability of nanorod ZnO to Acid Orange 7 in dye wastewater is the strongest, that is, when the flow field velocity is 5.5 m / s, the frequency of the swirl oscillation on the surface of nanorod ZnO matches the resonance frequency of this nanorod ZnO, and the strongest piezoelectric effect can be excited.

[0182] The above embodiments are only used to illustrate the technical concept and characteristics of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot be used to limit the protection scope of the present invention. All equivalent transformations or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A piezoelectric effect excitation method, characterized in that, Apply mechanical stress to the piezoelectric catalytic material particles through swirl oscillation.

2. The piezoelectric effect excitation method according to claim 1, characterized in that, The swirl oscillation is generated by a strong helical flow reactor.

3. The piezoelectric effect excitation method according to claim 2, characterized in that, The piezoelectric effect excitation method specifically includes the following steps: S1. Disperse the piezoelectric catalytic material particles in a first solution to form a mixed system of piezoelectric catalytic material particles and the first solution. S2. Control the first solution dispersed with piezoelectric catalytic material particles to enter the strong helical flow reactor at a high first tangential velocity, so that a strong three-dimensional rotating flow field is formed in the strong helical flow reactor. The piezoelectric catalytic material particles follow the rotation with the rotation of the three-dimensional rotating flow field. During the movement, the piezoelectric catalytic material particles are deformed under the action of the swirl oscillation mechanical stress and generate surface charges. S3. Under the action of the continuous mechanical stress, the charges inside the piezoelectric catalytic material particles accumulate on the surface area of the piezoelectric catalytic material particles. S4. The charges accumulated on the surface area of the piezoelectric catalytic material particles are transferred in the first solution to generate catalytically active substances, which further participate in chemical reactions.

4. The piezoelectric effect excitation method according to claim 3, characterized in that In the step S2, the first tangential velocity is 1-8 m / s.

5. The piezoelectric effect excitation method according to claim 3, characterized in that, The strong helical flow reactor is a cylindrical reactor. The top of the cylindrical reactor is provided with a first tangential inlet, and the bottom is provided with a first outlet.

6. The piezoelectric effect excitation method according to claim 5, wherein, The cylindrical reactor is equipped with a power device for controlling the tangential velocity of the first solution at the first tangential inlet to be the first tangential velocity.

7. The piezoelectric effect excitation method according to claim 6, characterized in that The first outlet is a tangential outlet.

8. The piezoelectric effect excitation method according to claim 1, characterized in that, The piezoelectric catalytic material is one or more of barium titanate, zinc oxide, zinc sulfide, titanium oxide, lithium tantalate, strontium titanate, bismuth ferrite, molybdenum sulfide, lead zirconate titanate, C3N4.

9. The piezoelectric effect excitation method according to claim 8, characterized in that, When the piezoelectric catalytic material is molybdenum sulfide, the first tangential velocity is 6.6 m / s; when the piezoelectric catalytic material is zinc oxide, the first tangential velocity is 5.5 m / s.

10. Application of the piezoelectric effect excitation method according to any one of claims 1-9 in the field of wastewater treatment.

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