Friction nano-generator for collecting fluid energy, preparation method of friction nano-generator and application of friction nano-generator in heavy metal ion removal

Abstract

The invention discloses a friction nano-generator capable of collecting fluid energy, a preparation method of the friction nano-generator and application of the friction nano-generator in heavy metal ion removal, and belongs to the technical field of nano-generators. The invention discloses a fluid energy collection friction nano-generator. The fluid energy collection friction nano-generator comprises a base, a plurality of supporting plates, stress turbine blades, a rotating shaft, a contact separation assembly and a sliding friction assembly. Through structural innovation and optimization, high voltage is realized by using a contact separation mode, and meanwhile, high current output is realized by considering an independent layer mode. The composite structure design improves the adaptability of the system, so that the system can keep efficient energy conversion in various working environments, and the limitation of unbalanced voltage and current output in the traditional design is overcome. The composite design not only breaks through the power bottleneck of the traditional TENG, but also provides a new idea for efficient energy capture in a more complex mechanical environment. Compared with the prior art, the electric output performance and the device operation are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nanogenerators, and more particularly to a triboelectric nanogenerator for fluid energy harvesting, its preparation method, and its application in heavy metal ion removal. Background Art

[0002] As an emerging energy harvesting technology, TENG (triboelectric nanogenerator) has received extensive attention due to its high efficiency and environmental adaptability in low-frequency mechanical energy conversion. The structural design of traditional TENGs is often based on a single working mode, such as only using contact separation or sliding friction. However, although the traditional single mode can achieve effective energy conversion to a certain extent, it is often difficult to balance high voltage output and continuous current stability, and the limitations of material selection and structural design restrict its performance breakthrough.

[0003] With the development of social economy, the pollution problem of heavy metal ions has become increasingly serious. Heavy metal ions mainly come from various industries such as printing, chemical engineering, and electroplating. Heavy metal ions such as lead ions, cadmium ions, and copper ions exist in water resources and soil due to their strong toxicity and difficult degradation, causing great impacts on the ecological environment and human health. Traditional methods for removing heavy metal ions include chemical precipitation, membrane separation, and adsorption. Although these methods can effectively remove heavy metal ions, they often have problems such as high energy consumption, high cost, secondary pollution, and complex operation.

[0004] Therefore, how to develop a triboelectric nanogenerator for fluid energy harvesting that can overcome the limitations of unbalanced voltage and current output in traditional designs, improve electrical output performance, and its preparation method and application in heavy metal ion removal are technical problems that need to be urgently solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a triboelectric nanogenerator for fluid energy harvesting, its preparation method, and its application in heavy metal ion removal.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A triboelectric nanogenerator for fluid energy harvesting, comprising: a base, a plurality of support plates, a force-receiving turbine fan blade, a rotating shaft, a contact separation assembly, and a sliding friction assembly;

[0008] The support plates are fixedly installed on both sides of the base. Bearings are respectively inlaid at the tops of the support plates. The rotating shaft is rotatably connected to the support plates through the bearings. The force-receiving turbine fan blade includes a mounting portion and a plurality of blades. The plurality of blades are fixedly connected to the outer periphery of the mounting portion. The force-receiving turbine fan blade is fixedly installed at one end of the rotating shaft through the mounting portion. The contact separation assembly and the sliding friction assembly are respectively installed on the rotating shaft;

[0009] The contact separation assembly includes a first rotor inlaid with a plurality of universal balls, a balloon film, a fixed disc provided with a plurality of inlaid holes, a plurality of copper electrodes coated with an Ecoflex / ZnS film, a plurality of copper electrodes covered with a sponge film, a gasket, a first stator, and a first bracket and a second bracket. The gasket and the copper electrode covered with the sponge film are respectively fixedly connected to the first stator. The thickness of the gasket is greater than the thickness of the copper electrode covered with the sponge film. The copper electrode coated with the Ecoflex / ZnS film is inlaid in the inlaid hole of the fixed disc. The Ecoflex / ZnS film is close to the sponge film. The balloon film covers the surface of the fixed disc. The universal balls are in close contact with the balloon film;

[0010] A through hole is provided at the centers of the first rotor, the balloon film, the fixed disc, and the first stator. The rotating shaft passes through the through hole at the center of the first rotor and is fixedly connected to the first rotor. The rotating shaft sequentially passes through the through holes of the balloon film, the fixed disc, and the first stator. The diameters of the through holes of the balloon film, the fixed disc, and the first stator are greater than the diameter of the rotating shaft. The first stator is fixedly installed on the first bracket. The fixed disc is fixedly installed on the second bracket. The first bracket and the second bracket are respectively fixedly installed on the base;

[0011] The sliding friction assembly includes a second rotor, a second stator, and a third bracket. The main bodies of the second rotor and the second stator are PCBs. Grid-shaped copper electrodes are uniformly provided on the second rotor and the second stator. A PTFE layer is pasted on the copper electrode of the second rotor. A GF film is pasted on the copper electrode of the second stator. The PTFE layer and the GF film are in close contact;

[0012] A through hole is provided at the centers of the second rotor and the second stator. The rotating shaft passes through the through hole of the second rotor and is fixedly connected to the second rotor. The rotating shaft passes through the through hole of the second stator. The diameter of the through hole of the second stator is greater than the diameter of the rotating shaft. The second stator is fixedly installed on the third bracket. The third bracket is fixedly installed on the base.

[0013] Furthermore, the shape of Rotor 1 is a circle with a diameter of 200 mm, with a 6-mm through-hole in the center. The material is acrylic and the thickness is 12 mm. The diameter of the universal ball is 18 mm, the material is bearing steel, and the height that the universal ball protrudes from Rotor 1 is 5 mm. The shape of the balloon film is a circle with a diameter of 200 mm, with an 8-mm through-hole in the center. The material is latex and the thickness is 0.04 mm. The shape of the fixed disc is a circle with a diameter of 200 mm, with an 8-mm through-hole in the center. The material is acrylic and the thickness is 4 mm. The shape of the inlay holes is multiple squares with a side length of 5 cm. The shape of the copper electrodes coated with Ecoflex / ZnS film is multiple squares with a side length of 5 cm. Among them, the thickness of the copper electrode layer is 0.065 mm, and the thickness of the Ecoflex / ZnS film is 0.1 mm. The shape of the copper electrodes covered with sponge film is multiple squares with a side length of 5 cm. Among them, the thickness of the copper electrode layer is 0.065 mm, and the thickness of the sponge film is 0.5 mm. The shape of the gasket is strip-shaped, the material is acrylic, and the thickness is 5 mm. The shape of Stator 1 is a circle with a diameter of 200 mm, with an 8-mm through-hole in the center. The material is acrylic and the thickness is 5 mm. When the universal ball does not rotate into the inlay holes, the distance between the sponge film and the Ecoflex / ZnS film is 5 mm. The positions of multiple copper electrodes coated with Ecoflex / ZnS film and multiple copper electrodes covered with sponge film correspond one by one. When the universal ball rotates into the inlay holes, the positions of multiple universal balls and multiple inlay holes correspond one by one.

[0014] Furthermore, the shape of Rotor 2 is a circle with a diameter of 200 mm, with a 6-mm through-hole in the center. The copper electrodes on Rotor 2 are arranged in an annular shape with an outer diameter of 200 mm and an inner diameter of 70 mm centered on the center of Rotor 2. The number of grids is 30 and they are evenly distributed. The shape of Stator 2 is a square with a side length of 200 mm, with an 8-mm through-hole in the center. The copper electrodes on the stator are arranged in an annular shape with an outer diameter of 200 mm and an inner diameter of 70 mm centered on the center of Stator 2. The number of grid pairs is 30 and they are evenly distributed. One grid is selected and extended on each side of the copper electrodes on the stator as the wiring terminal.

[0015] Furthermore, the thickness of the PTFE layer is 0.01 mm. The PTFE layer has the same shape as Rotor 2 and completely covers Rotor 2 when pasted. The thickness of the GF film is 0.15 mm. The GF film has the same shape as Stator 2 and completely covers Stator 2 when pasted.

[0016] Further, the base, the support plate, the first bracket, the second bracket and the third bracket are all made of wood. The base has a size of 35 cm in length and 20 cm in width. The support plate is trapezoidal, with its lower base length of 14 cm, upper base length of 5 cm, and height of 14 cm. The first stator is embedded on the first bracket, the fixed disc is embedded on the second bracket. The first bracket and the second bracket have a height of 140 mm and a width of 200 mm. The second stator is embedded on the third bracket, and the third bracket has a height of 140 mm and a width of 220 mm. The rotating shaft has a length of 305 mm and a diameter of 5 mm, and is made of carbon steel.

[0017] The present invention also provides a preparation method of a triboelectric nanogenerator for fluid energy harvesting, comprising the following steps:

[0018] (1) Fabricating a copper electrode coated with an Ecoflex / ZnS thin film: adding ZnS powder into Ecoflex silica gel and stirring to obtain a uniform mixture, uniformly coating the obtained mixture on the surface of a wooden board on which a copper electrode has been pre-laid, transferring the coated sample to a vacuum drying oven for curing treatment to obtain a copper electrode coated with an Ecoflex / ZnS thin film;

[0019] (2) Installing according to the structure of the triboelectric nanogenerator for fluid energy harvesting to obtain the product of the present invention.

[0020] Further, in step (1), the ZnS powder accounts for 0 - 13 wt% of the total mass of the ZnS powder and Ecoflex silica gel, the coating thickness is 0.1 mm, the curing treatment temperature is 60 °C, and the curing treatment time is 4 h.

[0021] Preferably, in step (1), the ZnS powder accounts for 9 wt% of the total mass of the ZnS powder and Ecoflex silica gel.

[0022] Further, in step (1), the obtained mixture is uniformly coated on the surface of the wooden board on which the copper electrode has been pre-laid by spin coating at a rotation speed of 1000 r / min.

[0023] The present invention also provides an application of the triboelectric nanogenerator for fluid energy harvesting in the removal of heavy metal ions.

[0024] Further, a triboelectric nanogenerator for fluid energy harvesting is used to construct an electrodeposition system to remove Cu 2+ 、Pb 2+ and Cd 2 + .

[0025] Advantages of the present invention: The present invention proposes a composite triboelectric nanogenerator (RCS-TENG) that combines contact-separation mode and rotation-independent layer mode to work together. Through structural innovation and optimization, high voltage is achieved using the contact-separation mode, while high current output is achieved considering the independent layer mode at the same time. This composite structure design improves the adaptability of the system, enabling it to maintain high-efficiency energy conversion in various working environments and overcoming the limitations of unbalanced voltage and current output in traditional designs. As a wide-bandgap semiconductor material, ZnS has a high electronegativity and a good electronic structure, effectively improving the surface charge transfer efficiency of the material and thus enhancing the triboelectric effect. Therefore, Ecoflex elastomer doped with ZnS is used as the triboelectric layer, paired with a porous sponge structure, to construct this contact-separation mode triboelectric nanogenerator (EZ-TENG). We use PTFE (polytetrafluoroethylene) and (GF) glass fiber as two triboelectric layers to construct a rotation-independent layer triboelectric nanogenerator (PG-TENG). Due to its extremely low surface energy and excellent wear resistance, PTFE can significantly reduce energy loss and increase the output current. The introduction of glass fiber further enhances the mechanical strength and durability of the structure, making it suitable for high-frequency and long-time frictional movements. This composite design not only breaks through the power bottleneck of traditional TENGs but also provides new ideas for efficient energy capture in complex mechanical environments.

[0026] The driving part is composed of a turbine blade structure. This structure has the following main advantages compared with the former water scoops. Since the blades are evenly distributed, the blades are more evenly stressed when the water flow acts, and the rotation process is stable. At the same time, the blades can guide the water flow direction when rotating, enabling the kinetic energy of the water to be more effectively utilized while reducing the energy loss caused by the dispersion of the water flow. Brief Description of the Drawings

[0027] Figure 1 Schematic diagram for the preparation of the triboelectric layer of EZ-TENG.

[0028] Figure 2 XRD characterization diagrams of ZnS and Ecoflex / ZnS.

[0029] Figure 3 COMSOL simulation diagrams of EZ-TENG, where i is the simulation diagram when the two triboelectric layers are in contact; ii is the simulation diagram when the two triboelectric layers are separated by 0.5 cm; iii is the simulation diagram when the two triboelectric layers are separated by 3.5 cm; iv is the simulation diagram when the two triboelectric layers are slowly approaching to 0.5 cm.

[0030] Figure 4Schematic diagram of the working principle of EZ-TENG, where i is the schematic diagram of the initial state; ii is the schematic diagram when the two friction layers are in contact; iii is the schematic diagram when the two friction layers start to separate; iv is the schematic diagram when the separation of the two friction layers is maximum; v is the schematic diagram when the two friction layers slowly approach each other.

[0031] Figure 5 Test result diagram of the electrical output performance of EZ-TENG under different mass ratios of ZnS, where (a) is the test result diagram of the output voltage of different mass ratios of ZnS; (b) is the test result diagram of the output current of different mass ratios of ZnS.

[0032] Figure 6 Test result diagram of the electrical output performance of EZ-TENG at different frequencies; where (a) is the test result diagram of the output voltage of EZ-TENG at different frequencies; (b) is the test result diagram of the output current of EZ-TENG at different frequencies.

[0033] Figure 7 Test result diagram of the electrical output performance of EZ-TENG, where (a) is the test result diagram of the long-term stability of EZ-TENG; (b) is the charging time curve diagram of different capacitors; (c) is the test result diagram of the voltage and current output under different loads; (d) is the peak power density diagram.

[0034] Figure 8 CAD diagram and physical diagram of the rotor and stator, where (a) is the CAD diagram of the rotor; (b) is the CAD diagram of the stator; (c) is the physical diagram of the rotor; (d) is the physical diagram of the stator.

[0035] Figure 9 Physical diagram of the rotor with attached PTFE and physical diagram of the stator with attached GF, where (a) is the physical diagram of the rotor with attached PTFE; (b) is the physical diagram of the stator with attached GF.

[0036] Figure 10 COMSOL simulation diagram of PG-TENG, where i is the simulation diagram when PTFE is on the left electrode; ii is the simulation diagram during the process when PTFE starts to slide from the left electrode to the right electrode; iii is the simulation diagram when PTFE is about to move onto the right electrode; iv is the simulation diagram when PTFE moves to the right electrode.

[0037] Figure 11 Working principle diagram of PG-TENG.

[0038] Figure 12 Test result diagram of the electrical output of PG-TENG at different stator-rotor spacings, where (a) is the test result diagram of the open-circuit voltage of PG-TENG at different stator-rotor spacings; (b) is the test result diagram of the short-circuit current of PG-TENG at different stator-rotor spacings.

[0039] Figure 13 It is a test result graph of the electrical output of the PG-TENG at different rotational speeds. Among them, (a) is the test result graph of the open-circuit voltage of the PG-TENG at different rotational speeds; (b) is the test result graph of the short-circuit current of the PG-TENG at different rotational speeds.

[0040] Figure 14 It is a test result graph of the electrical output performance of the PG-TENG. Among them, (a) is the test result graph of the long-term stability of the output voltage of the PG-TENG; (b) is the test result graph of the long-term stability of the output current of the PG-TENG; (c) is the test result graph of the voltage and current output under different loads; (d) is the peak power density graph of the PG-TENG.

[0041] Figure 15 It is the charging time curve graph of the PG-TENG for different capacitors.

[0042] Figure 16 It is the structural design graph of the RCS-TENG. Among them, (a) is the right view of the RCS-TENG; (b) is the top view of the RCS-TENG; (c) is the front view of the RCS-TENG; (d) is the rear view of the RCS-TENG.

[0043] Figure 17 It is the output test result graph of the RCS-TENG. Among them, (a) is the test result graph of the output voltage of the RCS-TENG at different water flow velocities; (b) is the test result graph of the output current of the RCS-TENG at different water flow velocities; (c) is the graph of the RCS-TENG lighting up the "TENG" pattern small lamp in an environment with a flow velocity of 0.7 m / s.

[0044] Figure 18 It is the schematic diagram of heavy metal ion electrodeposition.

[0045] Figure 19 It is the circuit diagram of the rectifier and voltage regulator module.

[0046] Figure 20 It is the circuit diagram of the maximum power tracking module.

[0047] Figure 21 It is the U0-t curve graph measured under the conditions of R = 100 kΩ, C = 10 μF, and L = 100 μH. The response approaches the steady state within 7 seconds. The inset shows that the DC component is 9.12 V and the ripple is 0.01 V.

[0048] Figure 22The U0-t curve diagram measured at different resistance values ​​and the DC component and ripple diagram of the output voltage at different resistance values, where (a) is the U0-t curve diagram measured at different resistance values; (b) is the DC component and ripple diagram of the output voltage at different resistance values.

[0049] Figure 23 The U0-t curve and the DC component and ripple diagram of the output voltage are measured at different capacitance values ​​and different inductance values, where (a) is the U0-t curve measured at different capacitance values; (b) is the DC component and ripple diagram of the output voltage at different capacitance values; (c) is the U0-t curve measured at different inductance values; (d) is the DC component and ripple diagram of the output voltage at different inductance values.

[0050] Figure 24 Comparison chart of direct charging and charging of a 1 mF capacitor via a PMM circuit.

[0051] Figure 25 Diagram of the heavy metal ion removal platform driven by RCS-TENG.

[0052] Figure 26 The results of the copper ion removal experiment are shown in Figure 1, where (a) is a physical picture of the anode graphite and cathode titanium plate; (b) is a physical picture of Cu deposited on the cathode titanium plate at different times and a color change picture of the solution; (c) is an EDS characterization picture of Cu attached to the titanium plate electrode.

[0053] Figure 27 Figure 3 is the relationship between the removal rate of Cu and time at different concentrations, different pH values ​​and different distances between the anode and cathode of the electrode plate, where (a) is the relationship between the removal rate of Cu and time at different concentrations; (b) is the relationship between the removal rate of Cu and time at different pH values; (c) is the relationship between the removal rate of Cu and time at different distances between the anode and cathode of the electrode plate.

[0054] Figure 28 The figures are the experimental results of lead ion removal, where (a) is the relationship between the removal rate of Pb and time at different concentrations; (b) is the actual picture of Pb deposited on the cathode titanium plate at different times; and (c) is the EDS characterization of Pb attached to the titanium plate electrode.

[0055] Figure 29 Figure 1 is a graph showing the relationship between the removal rate of Pb and time at different pH values ​​and at different distances between the anode and cathode of the electrode plate, where (a) is a graph showing the relationship between the removal rate of Pb and time at different pH values; (b) is a graph showing the relationship between the removal rate of Pb and time at different distances between the anode and cathode of the electrode plate.

[0056] Figure 30The figures are the experimental results of cadmium ion removal, where (a) is the actual picture of the anode ruthenium iridium titanium electrode and the cathode titanium plate; (b) is the actual picture of Cd deposited on the cathode titanium plate at different times; (c) is the EDS characterization picture of Cd attached to the titanium plate electrode.

[0057] Figure 31 The figure is a relationship between the removal rate of Cd and time at different concentrations, different pH values ​​and different distances between the anode and cathode of the electrode plate, wherein (a) is a relationship between the removal rate of Cd and time at different concentrations; (b) is a relationship between the removal rate of Cd and time at different pH values; (c) is a relationship between the removal rate of Cd and time at different distances between the anode and cathode of the electrode plate.

[0058] Figure 32 It is a structural schematic diagram of stator 1, fixed disc and stator 2 being installed with bracket 1, bracket 2 and bracket 3 respectively.

[0059] Figure 33 Schematic diagram of the installation sequence of various structures of the contact separation component.

[0060] Figure 34 Schematic diagram of the structural breakdown of the contact separation component. DETAILED DESCRIPTION

[0061] Materials used in the embodiments of the present invention:

[0062] 1. Zinc sulfide (ZnS, 99.99%) was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.

[0063] 2. Ecoflex silicone (total net weight 0.90 kg) was purchased from Smooth-On, USA. How to use Ecoflex silicone: Mix Ecoflex silicone A and B in a 1:1 mass ratio to ensure uniform mixing.

[0064] 3. PTFE (thickness: 0.01 mm) was purchased from Shenzhen Le Shangjia Technology Co., Ltd., and GF (thickness: 0.15 mm) was purchased from Xiongxian Yujin Building Materials Co., Ltd.

[0065] Example 1

[0066] like Figure 1As shown in the figure, a copper electrode coated with an Ecoflex / ZnS thin film was fabricated: ZnS powder was added to Ecoflex silica gel and stirred. The ZnS powder accounted for 9 wt% of the total mass of the ZnS powder and Ecoflex silica gel to obtain a uniform mixture. The obtained mixture was uniformly coated on the surface of a wooden board with a pre-laid copper electrode by spin coating at a speed of 1000 r / min, and the coating thickness was 0.1 mm. The spin-coated sample was transferred to a vacuum drying oven for curing treatment. The curing treatment temperature was 60 °C, and the curing treatment time was 4 h to obtain a copper electrode coated with an Ecoflex / ZnS thin film.

[0067] Example 2

[0068] A copper electrode coated with an Ecoflex / ZnS thin film was fabricated: Compared with Example 1, except that the ZnS powder accounted for 0 wt% of the total mass of the ZnS powder and Ecoflex silica gel, the other steps and process parameters were the same.

[0069] Example 3

[0070] A copper electrode coated with an Ecoflex / ZnS thin film was fabricated: Compared with Example 1, except that the ZnS powder accounted for 3 wt% of the total mass of the ZnS powder and Ecoflex silica gel, the other steps and process parameters were the same.

[0071] Example 4

[0072] A copper electrode coated with an Ecoflex / ZnS thin film was fabricated: Compared with Example 1, except that the ZnS powder accounted for 6 wt% of the total mass of the ZnS powder and Ecoflex silica gel, the other steps and process parameters were the same.

[0073] Example 5

[0074] A copper electrode coated with an Ecoflex / ZnS thin film was fabricated: Compared with Example 1, except that the ZnS powder accounted for 11 wt% of the total mass of the ZnS powder and Ecoflex silica gel, the other steps and process parameters were the same.

[0075] Example 6

[0076] A copper electrode coated with an Ecoflex / ZnS thin film was fabricated: Compared with Example 1, except that the ZnS powder accounted for 13 wt% of the total mass of the ZnS powder and Ecoflex silica gel, the other steps and process parameters were the same.

[0077] 1. Performance test of silica / sulfide zinc-based contact-separation triboelectric nanogenerator (EZ-TENG)

[0078] 1.1 Characterization of the composite thin film of the tribo-layer material

[0079] The characterization of the Ecoflex / ZnS friction layer film in this invention is mainly carried out by X-ray diffraction (XRD). The XRD diffraction patterns of ZnS and Ecoflex / ZnS are as Figure 2 shown. A Rigaku D / Max 2500PC diffractometer (Cu Kα, λ = 1.5418 Å) was used to analyze the ZnS powder in the diffraction angle range of 10 - 60 o . The diffraction peaks of the ZnS powder are located at 2θ = 26.67 o , 28.43 o , 30.46 o , 47.34 o and 56.21 o , corresponding to the (010), (002), (011), (110) and (112) crystal planes, and all the diffraction peaks are consistent with those reported in the literature. It can be seen from the figure that ZnS is well composite on Ecoflex without the presence of other miscellaneous peaks, indicating that the Ecoflex / ZnS friction layer is successfully prepared.

[0080] 1.2 Simulation of the Performance of the Friction Layer Material and the Working Principle

[0081] The positive friction layer of the EZ-TENG is the Ecoflex / ZnS film, and the negative friction layer is the sponge. As Figure 3 shown, in this invention, the COMSOL Multiphysics software was used to simulate the change process of the potential distribution of the EZ-TENG in one working cycle. From the initial fully contact state to separation, complete separation and the start of contact, the potential difference is gradually formed and reaches the maximum, and finally decreases as the contact starts slowly. This change in potential difference is the basis for the TENG to convert mechanical energy into electrical energy. Through the COMSOL simulation, the change in potential distribution can be visually seen, which helps to understand and optimize the design of the EZ-TENG.

[0082] Figure 4Shows the working principle of the Ecoflex / ZnS-based triboelectric nanogenerator EZ-TENG. In the initial state, the Ecoflex / ZnS positive triboelectric layer and the sponge negative triboelectric layer are separated, EZ-TENG has not started to move, and no charge is accumulated. When the two triboelectric layer materials of EZ-TENG come into contact with each other, due to the different triboelectric series of the two triboelectric layers, the electrons on the surface of the triboelectric layers are transferred due to the contact of the triboelectric layers, and the sponge layer will obtain electrons from the Ecoflex / ZnS layer. At this time, the Ecoflex / ZnS layer is positively charged and the sponge layer is negatively charged. Since the charge distribution on the two triboelectric layers is symmetric at this time, no current is generated in the circuit. When the Ecoflex / ZnS layer and the sponge layer are gradually separated, due to electrostatic induction, the charge is redistributed and the electric field also begins to change, so the potential difference between the upper and lower layers increases. Due to the change in the potential difference, electrons start to flow along the external circuit to form a current at this time. When the two triboelectric layers are separated to the maximum distance, the potential difference is the largest at this time. Subsequently, when the two triboelectric layers slowly come into contact, a current in the opposite direction is formed in the external circuit at this time. After that, this process repeats, and EZ-TENG generates alternating current.

[0083] 1.3 Output performance test of the contact-separation type triboelectric nanogenerator

[0084] In order to enable EZ-TENG to have the best electrical output performance, the present invention regulates the mass ratio of the Ecoflex / ZnS triboelectric layer materials. First, in Examples 1-6, triboelectric layer films with different mass fractions (0 wt%, 3 wt%, 6 wt%, 9 wt%, 11 wt% and 13 wt%) of Ecoflex / ZnS were respectively prepared for electrical output tests, and the thicknesses of these films were kept almost the same. When the movement frequency of contact separation is 5 Hz, its electrical output signal is tested. From Figure 5As can be seen from Figures (a) and (b), when the mass fraction of ZnS in the Ecoflex / ZnS thin film is 9 wt%, the output values of the open-circuit voltage and short-circuit current of its TENG are the highest, with an open-circuit voltage of 743 V and a short-circuit current of 113 μA. When the mass ratio of ZnS in the Ecoflex / ZnS thin film ranges from 0 wt% to 9 wt%, both its open-circuit voltage and short-circuit current show an upward trend. This is because appropriate doping of ZnS can enhance the dielectric constant and surface charge density of Ecoflex. Its doping can introduce local energy levels and enhance the charge capture ability, thereby improving the charge transfer efficiency during the friction process. The high dielectric constant of ZnS helps reduce charge recombination and promotes the separation and accumulation of charges at the interface, thus improving the output performance. When the mass fraction of ZnS in the Ecoflex / ZnS thin film continues to increase, its open-circuit voltage and short-circuit current show a downward trend. When the doping concentration is too high, ZnS particles may aggregate in the Ecoflex matrix, resulting in uneven charge distribution on the surface of the friction layer, causing rapid reduction and leakage of charges. At the same time, the doping of excessive ZnS increases its interfacial resistance, reducing the electron transport efficiency. Therefore, 9% mass fraction of ZnS was selected for subsequent experiments in this invention.

[0085] To enable the EZ-TENG to still have efficient and stable output at low frequencies, its electrical output was tested under the conditions of 1 Hz to 5 Hz. As can be seen from Figure 6 Figures (a) and (b), as the frequency increases, its voltage has a slight upward trend. The current increases rapidly with the increase of frequency. As can be seen from the figure, under the low-frequency condition of 1 Hz, the EZ-TENG still maintains excellent voltage and current output, with an open-circuit voltage that can reach 512 V and a short-circuit current that can reach 57 μA.

[0086] To verify the long-term stability of the EZ-TENG, as shown in Figure 7 Figure (a), the long-term stability of the EZ-TENG was tested for 2000 s. As can be seen from the test figure, its output voltage hardly changes during the 2000 s test process, proving its excellent output stability. By connecting different capacitors (10 μF, 22 μF, 47 μF, 100 μF, 220 μF, and 470 μF) to the bridge rectifier circuit and charging them with the EZ-TENG. As can be seen from Figure 7 Figure (b), the 10 μF capacitor can reach 20 V in about 50 s. Its charging time is shortened by 11 times compared with the EPT-TENG, indicating that the EZ-TENG has a huge improvement in electrical output compared with previous work. Figure 7 Figure (c) shows the voltage and current conditions under different loads. According to Figure 7Figure (c) shows the voltage-current conditions under different loads. The peak power density of the EZ-TENG is as shown in Figure 7 Figure (d). When the load resistance is 5 MΩ, its power density reaches the maximum, and the peak power density is 2.56 W / m 2 . Its peak power density is 1.7 times higher than that of the EPT-TENG. This also fully confirms the excellent output performance of the EZ-TENG.

[0087] Example 7

[0088] The sliding friction assembly includes Rotor II, Stator II, and Bracket III. The main bodies of Rotor II and Stator II are PCBs. Grid-shaped copper electrodes are evenly arranged on Rotor II and Stator II. A PTFE layer is pasted on the copper electrodes of Rotor II, and a GF film is pasted on the copper electrodes of Stator II. The PTFE layer and the GF film are in close contact.

[0089] Through holes are provided at the centers of Rotor II and Stator II. The rotating shaft passes through the through hole of Rotor II and is fixedly connected to Rotor II. The rotating shaft passes through the through hole of Stator II. The diameter of the through hole of Stator II is larger than the diameter of the rotating shaft. Stator II is fixedly installed on Bracket III, and Bracket III is fixedly installed on the base.

[0090] Rotor II is in the shape of a circle with a diameter of 200 mm and a 6-mm through hole at the center. The copper electrodes on Rotor II are arranged in an annular shape with an outer diameter of 200 mm and an inner diameter of 70 mm centered on the center of Rotor II. The number of grids is 30 and they are evenly distributed (the annular shape is equally divided into 60 grids, and a grid copper electrode is set every other grid); Stator II is in the shape of a square with a side length of 200 mm and an 8-mm through hole at the center. The copper electrodes on the stator are arranged in an annular shape with an outer diameter of 200 mm and an inner diameter of 70 mm centered on the center of Stator II. The number of grids is 30 pairs and they are evenly distributed (the annular shape is equally divided into 60 grids, and a grid copper electrode is set for each grid). One grid is selected and extended on each side of the copper electrodes on the stator as the wiring terminal.

[0091] The thickness of the PTFE layer is 0.01 mm. The PTFE layer has the same shape as Rotor II and completely covers Rotor II when pasted; the thickness of the GF film is 0.15 mm. The GF film has the same shape as Stator II and completely covers Stator II when pasted.

[0092] The CAD drawings of Rotor II without the PTFE layer pasted and Stator II without the GF film pasted are as shown in Figure 8 Figures (a) and (b). The physical drawings of Rotor II without the PTFE layer pasted and Stator II without the GF film pasted are as shown in Figure 8 Figures (c) and (d). The physical drawings of Rotor II and Stator II are as shown in Figure 9 Figures (a) and (b).

[0093] 2. Performance test of glass fiber-PTFE based rotary friction nanogenerator

[0094] 2.1 Performance simulation and working principle of rotary friction nanogenerator

[0095] In order to verify and explain the working mechanism of PG-TENG, the present invention uses COMSOL Multiphysics finite element simulation software to simulate and analyze the potential distribution of PG-TENG in different states. Figure 10 As shown in the figure, the electrostatic balance is broken during the sliding process. As the PTFE material moves, the potential difference between the two copper electrodes changes, and the voltage generated ranges from -400 V to 400 V. When sliding from the left electrode to the right electrode, the electrode voltage increases to the left as the PTFE film slides, and vice versa.

[0096] The working principle diagram of PG-TENG is shown in the figure Figure 11 As shown in the figure, during the friction process, since PTFE is easier to obtain electrons than GF material, the surface of PTFE carries negative charge and the surface of GF carries positive charge. The charge carried by the copper electrode changes with the sliding of the PTFE material, and the two electrodes of the grid generate equal and opposite charges under the action of electrostatic induction. When the slider starts to slide, the slider slides from the left electrode to the right electrode. As the overlapping area of ​​the PTFE material and the left electrode gradually decreases, the overlapping area with the right electrode gradually increases. At this time, electrons will flow from the left electrode to the right electrode through the external load circuit, thereby generating current. When the PTFE moves to the right electrode, an equal amount of positive charge is generated on the right electrode. When the PTFE moves to the left, the charge is continuously transferred in the external circuit. At this time, the current flows from the right electrode to the left electrode through the external load. The PTFE film moves back and forth between adjacent electrodes according to this law, and the PG-TENG generates alternating current.

[0097] 2.2 Output performance test of rotary friction nanogenerator (PG-TENG)

[0098] In order to explore the optimal operating state of PG-TENG, the electrical output performance of different spacings between its rotor and stator was investigated. Figure 12Figures (a) and (b) show the open-circuit voltage and short-circuit current at different stator-rotor spacings. It can be seen from the figures that as the spacing increases, the open-circuit voltage and short-circuit current show a downward trend. This is because when the stator and rotor are in contact with each other, the contact area between PTFE and GF is large, and the triboelectric effect causes the charge transfer to be maximized, and the surface charge density reaches a peak. At this time, the contact area between PTFE and GF is the largest, the charge transfer between the positive and negative friction layers is the most sufficient, the separation of positive and negative charges is significant, and the voltage reaches the maximum value. As the spacing increases, the actual contact area decreases, the charge transfer efficiency decreases, the surface charge density decreases, and thus the output voltage decreases. Although PTFE and GF are not in direct contact, they still have relatively high open-circuit voltage and short-circuit current outputs. This is because as long as the vertical spacing is much smaller than the relative displacement of the two electrodes, the sliding of the charges on the PTFE film will still cause a large part of the charges to flow.

[0099] In addition, external factors have a great impact on the electrical output performance of the PG-TENG. For the rotational-mode triboelectric nanogenerator, its electrical output performance is related to the rotational speed. As shown in Figure 13 Figures (a) and 4-13-b, when the rotational speed increases from 150 r / min to 350 r / min, both the open-circuit voltage and short-circuit current of the PG-TENG show a linear growth trend. The main reason for this phenomenon is that when the rotational speed increases, the charge transfer rate will increase accordingly. Generally speaking, the output voltage of the TENG is independent of the rotational speed and usually remains constant. However, during the rotation of the PG-TENG, due to the slight instability during the operation of the motor, the rotor of the PG-TENG can obtain a larger rotational torque. When the rotational speed and torque increase, the contact between PTFE and GF becomes closer. Since GF has a fluffy and porous structure, when the contact becomes closer, GF will be further compressed, and the contact area increases, thereby increasing the surface charge density. This process further enhances the output performance of the PG-TENG. When the rotational speed is 350 r / min, the open-circuit voltage reaches 693 V and the current reaches 225 μA.

[0100] To ensure the stable operation of the PG-TENG during operation, the output voltage of the PG-TENG was tested continuously for 700 s, and the experimental results are shown in Figure 14 Figure (a). It can be seen from the experimental results that during the continuous 700-s test, its output voltage remains stable. The output current of the PG-TENG was tested continuously for 800 s, and the experimental results are shown in Figure 14 Figure (b). It can be seen from the test results that during the entire 800-s continuous operation, its output current always remains stable. As shown in Figure 14As shown in Figure (c), when the rotation speed is fixed at 300 r / min, as the external load resistance increases, the output current of the PG-TENG gradually decreases, while the peak value of the output voltage continuously rises. Finally, when the load resistance is set to 3 MΩ, the maximum peak power density of the PG-TENG reaches 11.69 W / m 2 , as Figure 14 shown in Figure (d). Compared with the EZ-TENG, its maximum peak power is increased by about 4.6 times, which demonstrates its excellent electrical output performance.

[0101] Due to the uncertainty of the TENG output, energy storage devices such as capacitors are often required. Therefore, the overall electrical energy output ability of the PG-TENG to different capacitors (22 μF, 33 μF, 47 μF, 110 μF, 220 μF, and 470 μF) was studied when the rotation speed was 300 r / min. The experimental results are as Figure 15 shown. The PG-TENG can quickly charge a 22 μF capacitor to 34 V within 25 s. The PG-TENG can quickly charge a 470 μF capacitor to 3.7 V within 50 s. The experiment shows that whether it is a capacitor with a large capacitance value or a small capacitance value, the PG-TENG can charge and store it in a short time. In subsequent experiments, selecting a suitable capacitor can effectively improve the efficiency of the entire system to meet different requirements.

[0102] Example 8

[0103] A triboelectric nanogenerator (RCS-TENG) for fluid energy harvesting was prepared using the copper electrode coated with Ecoflex / ZnS film prepared in Example 1 and the sliding friction assembly prepared in Example 7;

[0104] As Figures 32 - 34 shown, the triboelectric nanogenerator for fluid energy harvesting includes: a base, two support plates, a force-receiving turbine fan blade, a rotating shaft, a contact-separation assembly, and a sliding friction assembly;

[0105] The support plates are fixedly installed on both sides of the base. Bearings are respectively embedded at the top ends of the support plates. The rotating shaft is rotatably connected to the support plates through the bearings. The force-receiving turbine fan blade includes an installation part and a plurality of blades. The plurality of blades are fixedly connected to the outer periphery of the installation part. The force-receiving turbine fan blade is fixedly installed at one end of the rotating shaft through the installation part. The contact-separation assembly and the sliding friction assembly are respectively installed on the rotating shaft;

[0106] The contact separation component includes Rotor 1 inlaid with 4 universal balls, a balloon film, a fixed disk provided with inlaid holes, a copper electrode coated with an Ecoflex / ZnS film, a copper electrode covered with a sponge film, a gasket, Stator 1, and Bracket 1 and Bracket 2. The gasket and the copper electrode covered with the sponge film are respectively fixedly connected to Stator 1. The thickness of the gasket is greater than that of the copper electrode covered with the sponge film. The copper electrode coated with the Ecoflex / ZnS film is inlaid in the inlaid hole of the fixed disk. The Ecoflex / ZnS film is close to the sponge film. The balloon film covers the surface of the fixed disk. The universal balls are in close contact with the balloon film;

[0107] There is a through hole at the center of Rotor 1, the balloon film, the fixed disk, and Stator 1. The rotating shaft passes through the through hole at the center of Rotor 1 and is fixedly connected to Rotor 1. The rotating shaft sequentially passes through the through holes at the centers of the balloon film, the fixed disk, and Stator 1. The diameters of the through holes of the balloon film, the fixed disk, and Stator 1 are greater than the diameter of the rotating shaft. Stator 1 is fixedly installed on Bracket 1, the fixed disk is fixedly installed on Bracket 2, and Bracket 1 and Bracket 2 are respectively fixedly installed on the base;

[0108] Rotor 1 is circular with a diameter of 200 mm, has a through hole of 6 mm at the center, is made of acrylic, and has a thickness of 12 mm; the universal balls have a diameter of 18 mm, are made of bearing steel, and the height by which the universal balls protrude from Rotor 1 is 5 mm; the balloon film is circular with a diameter of 200 mm, has a through hole of 8 mm at the center, is made of latex, and has a thickness of 0.04 mm; the fixed disk is circular with a diameter of 200 mm, has a through hole of 8 mm at the center, is made of acrylic, and has a thickness of 4 mm. The inlaid holes are in the shape of multiple squares with a side length of 5 cm; the copper electrode coated with the Ecoflex / ZnS film is in the shape of multiple squares with a side length of 5 cm. Among them, the thickness of the copper electrode layer is 0.065 mm, and the thickness of the Ecoflex / ZnS film is 0.1 mm; the copper electrode covered with the sponge film is in the shape of 4 squares with a side length of 5 cm. Among them, the thickness of the copper electrode layer is 0.065 mm, and the thickness of the sponge film is 0.5 mm; the gasket is in the shape of a strip, is made of acrylic, and has a thickness of 5 mm; Stator 1 is circular with a diameter of 200 mm, has a through hole of 8 mm at the center, is made of acrylic, and has a thickness of 5 mm; when the universal balls do not rotate into the inlaid holes, the distance between the sponge film and the Ecoflex / ZnS film is 5 mm. The positions of the 4 copper electrodes coated with the Ecoflex / ZnS film and the 4 copper electrodes covered with the sponge film correspond one by one. When the universal balls rotate into the inlaid holes, the positions of the 4 universal balls and the 4 inlaid holes correspond one by one.

[0109] The base, support plate, bracket 1, bracket 2, and bracket 3 are all made of wood. The base has dimensions of 35 cm in length and 20 cm in width. The support plate is trapezoidal, with a lower base length of 14 cm, an upper base length of 5 cm, and a height of 14 cm. Stator 1 is embedded in bracket 1, and the fixed disk is embedded in bracket 2. Bracket 1 and bracket 2 have a height of 140 mm and a width of 200 mm. Stator 2 is embedded in bracket 3, and bracket 3 has a height of 140 mm and a width of 220 mm. The length of the rotating shaft is 305 mm, the diameter is 5 mm, and the material is carbon steel.

[0110] The overall structural design diagram of the RCS-TENG is as Figure 16 shown. The right view of the RCS-TENG is as Figure 16 shown in Figure (a) of Figure 16 and the views from all directions of the RCS-TENG are shown in Figures (b) and (c) of

[0111] 3. Performance Test of Rotating-Contact-Separation Triboelectric Nanogenerator

[0112] 3.1 Output Performance Test of Rotating-Contact-Separation Triboelectric Nanogenerator

[0113] The operation process of the RCS-TENG is as follows: When the water flow impacts the turbine fan blades of the device, the turbine fan blades generate a rotational motion under the action of the water flow, and further drive the connected rotating shaft to rotate synchronously. The rotation of the rotating shaft drives the movement of the rotor connected to it. The rotor mainly includes two parts: contact separation and rotational friction. Universal balls are embedded in the rotor of the contact separation part. During the rotation of the rotor, the universal balls slide along the balloon film on the surface of the stator, and when rotating to the hollow area of the contact separation part, due to the force, they press down on the Ecoflex / ZnS friction layer, making it closely contact with the sponge friction layer below. At this time, electron transfer occurs at the friction interface, realizing charge separation. When the rotor rotates further and the universal balls leave the hollow area, due to the disappearance of the external force, the Ecoflex / ZnS friction layer returns to its original state by its own elasticity and separates from the sponge friction layer, completing a complete contact-separation cycle process. In this system, four EZ-TENG units are connected in series. As the rotor continues to rotate, the contact-separation cycle process is continuously repeated, continuously outputting electrical energy. The rotor of the rotational friction part rotates with the shaft, and the PTFE material continuously slides and rubs against the GF material, generating alternating current. The contact separation part is connected in parallel with the rotational friction part to enhance its current output.

[0114] Next, the electrical output performance of the RCS-TENG under different flow velocity conditions is tested. Figure 17 in Figure (a) of Figure 17Figures (b) show the variations of the output voltage and output current when the water flow velocity gradually increases from 0.5 m / s to 1.3 m / s. The experimental results show that with the increase in flow velocity, both the open-circuit voltage and short-circuit current of the RCS-TENG show an upward trend. This phenomenon is mainly attributed to the enhanced impact force of the water flow on the stressed water scoop, which increases the rotation speed of the stressed water scoop, thereby driving the synchronous increase in the rotation speed of the rotating shaft. Since the rotating shaft is connected to the rotor, the rotation speed of the rotor also increases, further affecting the force exerted by the universal ball embedded in the rotor on the Ecoflex / ZnS friction layer. When the rotor rotates faster, the periodic contact pressure of the universal ball on the friction layer increases, and the rotation speed of the rotational friction part increases, thereby enhancing the triboelectric charging effect and improving the overall output voltage and current. In addition, a higher flow velocity not only speeds up the movement rhythm of the entire system but also reduces the energy loss that may be caused by low-speed operation, enabling the RCS-TENG to perform energy conversion more efficiently at higher flow velocities. Therefore, within the test range, both the open-circuit voltage and short-circuit current of the RCS-TENG increase steadily with the increase in water flow velocity, verifying the response characteristics of the system to flow velocity changes. At a flow velocity of 1.3 m / s, its voltage can reach 702 V and its current can reach 255 μA. The RCS-TENG lights up the small "TENG" pattern lamp in the environment of a 0.7 m / s flow velocity as Figure 17 shown in Figure (c).

[0115] Conclusion: The present invention constructs a hybrid triboelectric nanogenerator (RCS-TENG) that combines the contact-separation mode and the independent-layer mode, taking into account its electrical output performance of high voltage and high current. The contact-separation mode material is prepared by spin-coating the Ecoflex / ZnS thin film. When the load resistance is 5 MΩ, its power density reaches the maximum, and the peak power density is 2.56 W / m 2 which is 1.7 times higher than that of the EPT-TENG. Under the low-frequency condition of 1 Hz, the open-circuit voltage of the EZ-TENG can reach 512 V, and the short-circuit current can reach 57 μA. When the rotation speed of the PG-TENG is 350 r / min, its open-circuit voltage can reach 693 V, and the current can reach 225 μA. The two-mode TENGs complement each other and work synergistically under low-frequency and high-frequency conditions. This composite design not only breaks through the power limitation of traditional TENGs but also provides a new idea for achieving efficient energy capture in complex mechanical environments. Compared with previous studies, the present invention has achieved a significant improvement in electrical output performance.

[0116] 4. Application of triboelectric nanogenerators for fluid energy harvesting in heavy metal ion removal.

[0117] The present invention develops an electroplating heavy metal ion system by combining a triboelectric nanogenerator with a power management circuit (PMM). Since the RCS-TENG has the best electrical output performance, the RCS-TENG is selected and combined with the PMM circuit. By designing the power management circuit, the output voltage ripple of the TENG is reduced, the stability during the electroplating process is improved, and the heat loss during the driving process is reduced. The stable output voltage ensures the uniformity and controllability of the electroplating reaction.

[0118] 4.1 Heavy metal ion removal platform based on triboelectric nanogenerator

[0119] 4.1.1 Principle of heavy metal ion removal by electroplating

[0120] The principle of removing heavy metal ions by electroplating is as Figure 18 shown.

[0121] 4.1.2 Power management circuit design and optimization

[0122] The circuit diagram of the power management circuit is as Figure 19 shown. The entire power management circuit mainly consists of a voltage and current stabilization module and a maximum power tracking module. The maximum power tracking module is as Figure 20 shown. The capacitors, inductors, and resistors of the power management module were tested in detail to determine their optimal output, ensuring that the power management module can provide efficient and stable electrical energy output under various different working environments. This power management module is based on the maximum energy transfer strategy, DC buck conversion, and self-management mechanism. As Figure 21 shown, the U0-t curve measured under the conditions of R = 100 kΩ, C = 10 μF, and L = 100 μH. The output voltage continuously rises from the initial state and reaches a steady state within 7 s. The enlarged view in the inset shows that the DC component at steady state is 9.12 V and the ripple is 0.01 V. This is consistent with the theoretical research in the power management circuit part of the literature and is very close to the voltage of traditional electronic devices and the electrical output requirements of the electrolytic cell.

[0123] When different resistance values are used in the circuit, under the conditions of capacitance C = 5 μF and inductance L = 100 μH, the output voltage at steady state is as Figure 22 shown in Figure (a), and the DC component and ripple values of the output voltage at different resistance values are summarized in Figure 22 Figure (b). It can be clearly seen that as the resistance increases, the DC component increases and the ripple generally shows a decreasing trend. At the same time, as the resistance value increases, its output voltage also increases. In order to better conduct the electroplating experiment and meet the driving voltage of heavy metal ions, R = 100 kΩ is selected.

[0124] In the PMM circuit, capacitance and inductance are important parameters. The present invention has conducted a detailed exploration of these parameters. Figure 23 Figures (a) and (b) show the output voltage characteristics at steady state with varying capacitance values under the conditions of resistance R = 100 kΩ and inductance L = 100 μH; while Figure 23 Figures (c) and (d) show the output voltage characteristic curves at steady state with varying inductance values under the conditions of resistance R = 100 kΩ and capacitance C = 10 μF. It can be clearly seen from the experimental result figures that changes in capacitance and inductance have little effect on their DC components because they do not consume energy. However, the ripple decreases significantly with the increase in capacitance and inductance, which is attributed to their energy storage and filtering characteristics.

[0125] Figure 24 The charging curves of directly charging a 1 mF capacitor by the RCS-TENG and charging a 1 mF capacitor through the PMM circuit at a flow rate of 0.7 m / s were compared. The experimental results show that within the same time, the RCS-TENG managed by the PMM circuit can charge the capacitor to a higher voltage during the charging process, which also confirms the advantages of the PMM power management circuit.

[0126] 4.1.3 Construction of the heavy metal ion removal platform

[0127] The heavy metal ion removal platform is as shown in Figure 25 and mainly consists of three parts: the RCS-TENG, the power management circuit, and the electrodeposition reaction cell. This platform combines the self-powered characteristic of converting mechanical energy into electrical energy with the application of electrochemical reactions, forming an innovative water treatment technology. Frictional electricity is generated by the RCS-TENG and its electrical output performance is enhanced through the PMM power management circuit. At the same time, its electrical output is rectified, stored, and regulated to ensure a smooth and stable electrical output for driving the electrochemical reactions in the electrodeposition reaction cell. Driven by the power management circuit, the electrodes in the electrodeposition cell start to function. Heavy metal ions in the solution undergo a reduction reaction at the cathode to form metals and deposit on the surface of the cathode electrode plate, thereby achieving the effect of removing heavy metal ions.

[0128] 4.2 Research on the removal of heavy metal ions by electrodeposition based on the rotary-contact separation triboelectric nanogenerator

[0129] 4.2.1 Copper ion removal experiment

[0130] First, when the initial pH value of the solution was 4, the voltage input was 9.12 V, and the distance between the anode and cathode plates was controlled at 20 mm, a series of CuSO4 solutions with different concentrations (1.5 g / L, 2 g / L, 2.5 g / L, and 3 g / L) were prepared under this condition. The electrode material selected was graphite as the anode and titanium plate as the cathode. The actual picture is as follows Figure 26 As shown in Figure (a). Figure 26 Figure (b) shows the actual picture of Cu deposited on the cathode titanium plate at different times in 2.5 g / L CuSO4 solution and the color change of the solution. EDS characterization of the deposited adhering substances on the electrode, such as Figure 26 As shown in Figure (c), it can be clearly seen from the characterization analysis that the deposit is Cu.

[0131] Figure 27 Figure (a) shows the relationship between the removal rate of copper and time at different concentrations. The experimental results show that the higher the copper ion concentration, the higher the copper removal efficiency. When the copper ion concentration is 1.5 g / L, the electrodeposition effect is poor, and the copper removal rate is 62%; when the copper concentration is 2 g / L, the electrodeposition effect is the best, and the removal rate can reach 80%; but when the copper ion concentration increases to 3 g / L, the copper removal rate decreases. The main reason is that when the copper ion concentration in the solution is 2+ When the concentration is low, as the reaction proceeds, Cu 2+ The concentration gradually decreases, resulting in a decrease in the diffusion rate and concentration polarization, so the removal rate of Cu is low. At higher concentrations, the total resistance of the electrochemical system decreases and the conductivity of the solution increases, which promotes the electrochemical reaction. However, if the concentration is too high, the distance between ions is shortened, resulting in an increase in the interaction force between ions, increasing the resistance between ions, slowing down the movement of ions, and thus affecting the removal of copper. During the removal process, as the reaction time increases, the removal rate of Cu gradually increases, and the initial removal rate is faster, and then tends to be stable. This is because during the electrodeposition process, the conductivity of the solution is related to the metal ion concentration, and Cu 2+ As the concentration increases, the conductivity increases, which helps Cu 2+ Migrate to the cathode, thereby accelerating the reaction and reducing energy consumption. As the reaction continues, the metal ions in the solution gradually precipitate on the cathode surface, causing the copper ion concentration in the solution to decrease continuously. 2+ When the concentration decreases, the number of metal ions available on the cathode surface decreases, making the electrolysis reaction more difficult. + and Cu 2+ A competitive reaction begins on the cathode surface, H + is preferentially reduced to generate H2, while Cu 2+ The reduction efficiency of Cu is reduced, resulting in a large amount of H2 precipitation from the electrode surface. The precipitation of H2 not only affects the2+ The removal efficiency is further exacerbated by the energy consumption of the system. Since the H2 evolution process consumes electrical energy, the system energy efficiency decreases, leading to an increase in the overall energy consumption during the electrolysis process, thereby reducing the copper removal effect and the overall electrolysis efficiency.

[0132] The acidity and alkalinity of the solution are very important for the removal process. Different acidity and alkalinity will result in different hydrogen ion concentrations in the solution, thereby having different effects on the reaction process. Figure 27 Figure (b) shows the relationship between the removal rate of Cu and the reaction time at different pH values. Since Cu 2+ produces Cu(OH)2 precipitation in alkaline solution, experiments were conducted at pH values of 3, 4, and 5. At this time, the solution concentration was configured to be 2.5 g / L, the voltage was 9.12 V, and the distance between the plates was 20 mm. When the pH value of the solution was 3, the removal rate of copper was the lowest. As the pH value increased, its removal rate continuously increased. When the pH value was too low, the H + content was high, and a large amount of hydrogen gas was generated at the cathode during the reaction process, inhibiting the deposition of copper. As the pH value continued to increase, the concentration of H + in the solution decreased, the hydrogen evolution reaction weakened, and at this time, the reduction reaction of Cu 2+ in the solution was the dominant reaction, so the removal efficiency of Cu would increase.

[0133] The distance between the anode and cathode electrode plates has a certain influence on the removal rate of Cu. Figure 27 Figure (c) explores the relationship between the removal rate of Cu and time at different distances between the graphite anode and the titanium plate cathode. At this time, the experimental conditions were maintained as a solution concentration of 2.5 g / L and a pH value of 5. Comparing the experimental results, it can be found that when the distance between the two electrode plates was 20 mm, the removal rate was the best. As the distance between the electrode plates increased, the removal rate showed a downward trend. This is because when the distance between the electrode plates increases, the flow rate of the electrolyte will increase accordingly. At this time, it will promote the convection and diffusion of ions in the solution, strengthen the mass transfer between heavy metal ions, and the electro-deposition efficiency will increase. When the distance is too small, it will lead to insufficient reaction of Cu 2+ , thus reducing the electro-deposition efficiency. When the distance is too large, Cu 2+ needs to migrate a longer path to reach the cathode. At the same time, when the plate distance is too large, the electric field strength decreases, so the electro-deposition efficiency decreases.

[0134] 4.2.2 Lead ion removal experiment

[0135] In order to explore the removal effect of lead ions at different concentrations, a series of Pb(CH3COO)2 solutions with different concentrations (1.5 g / L, 2 g / L, 2.5 g / L, 3 g / L) were prepared under the conditions of an initial solution pH of 4, a voltage input of 9.12 V, and a distance between the anode and cathode plates of 20 mm. Graphite was selected as the anode and titanium plate as the cathode. Figure 28 Figure (a) shows the relationship between lead removal rate and time. Figure 28 Figure (b) shows the actual picture of Pb deposited on the cathode titanium plate at different times and the color change of the solution in a 2.5 g / L Pb(CH3COO)2 solution. The experimental results show that when the solution concentration is 2 g / L, the Pb removal rate is as high as 82.7%. At this time, the concentration is moderate, which not only provides sufficient driving force for ion migration, but also avoids the concentration polarization phenomenon caused by excessive concentration. When the concentration is 1.5 g / L, the Pb removal rate is the lowest. This is because at low concentrations, as the reaction proceeds, Pb 2+ The concentration gradually decreases, resulting in a decrease in diffusion rate and concentration polarization, which ultimately reduces the removal efficiency of Pb. 2+ When the concentration is too high, the distance between ions is shortened, and the interaction force between ions increases. Therefore, the resistance to the mutual movement of ions increases, and the movement speed slows down, making the removal effect of Pb worse. At the same time, side reactions may be enhanced at high concentrations, further affecting the removal rate. EDS characterization of the deposits on the electrode, such as Figure 28 As shown in Figure (c), it can be clearly seen from the characterization analysis that the sediment is Pb.

[0136] The reaction conditions are that the concentration of Pb(CH3COO)2 solution is 2 g / L, the distance between the electrode plates is 20 mm, and the input voltage is 9.12 V. Under these conditions, the relationship between the removal rate of Pb and time at different pH values ​​was investigated. The experimental results are as follows: Figure 29 The experimental results show that the removal efficiency decreases with the increase of pH value. This is because when the acidity of the solution is strong, the H + The content is high, the mass transfer rate of hydrogen is high, the overpotential of H2 precipitation caused by concentration polarization phenomenon is low, the reaction rate of hydrogen precipitation is fast, and the hydrogen precipitation ability is strong at this time. 2+ Therefore, the lower the pH value, the lower the removal rate of Pb. When the pH value is 5, Pb 2+ The main reaction is the precipitation of Pb, and the hydrogen evolution reaction has little effect on it. At this time, the removal rate of Pb is the highest, which can reach 86.9%.

[0137] Figure 29Figure (b) explores the relationship between the removal rate of Pb and time at different distances between the graphite anode and the titanium plate cathode under the experimental conditions of a solution concentration of 2 g / L and a pH value of 5. The experimental results show that the removal rate is optimal when the distance between the two electrode plates is 20 mm. As the distance between the electrode plates increases, the removal rate shows a downward trend. This is because when the distance between the electrode plates increases, the flow rate of the electrolyte will increase, which will promote the convection and diffusion of ions in the solution, enhance the mass transfer between heavy metal ions, and improve the efficiency of electrodeposition. When the distance is too small, it will cause Pb 2+ The reaction is insufficient, thus reducing the electrodeposition efficiency. When the distance is too large, Pb 2+ It needs to migrate a longer path to reach the cathode. At the same time, the distance between the plates is too large, the electric field strength is reduced, and the electrodeposition efficiency is reduced.

[0138] 4.2.3 Cadmium ion removal experiment

[0139] The removal system was used to explore the removal effect of cadmium ions at different concentrations, different pH values, and different spacings between electrode plates. Ruthenium-iridium-titanium electrode is an inert metal oxide electrode with extremely high corrosion resistance in acidic solutions containing Cl⁻, and can maintain the activity of the electrode surface for a long time. Titanium electrode can form a dense TiO2 passivation film in a solution containing Cl⁻, which does not affect the reduction reaction of cadmium and the conductivity of titanium electrode is moderate. Therefore, ruthenium-iridium-titanium electrode was selected as the anode and titanium as the cathode. Figure 33 Figure (a) is a physical picture of the electrode. Figure 33 Figure (b) shows the actual images of Cd deposited on the cathode titanium plate at different times. Figure 33 Figure (c) shows the EDS characterization of the deposited material on the electrode. It can be clearly seen from the characterization analysis that the deposited material is Cd.

[0140] In order to explore the different concentrations of Cd 2+ To investigate the removal effect of CdCl2, a series of CdCl2 solutions with different concentrations (1.5 g / L, 2 g / L, 2.5 g / L, and 3 g / L) were prepared under the conditions of an initial solution pH of 5, a voltage input of 9.12 V, and a distance between the anode and cathode plates of 20 mm. The experimental results are shown in Figure 2. Figure 31 The experimental results show that with the increase of concentration, the removal rate of Cd continues to increase. When the solution concentration is 3 g / L, the removal rate of Cd is as high as 74.7%.

[0141] The reaction conditions were CdCl2 solution concentration of 3 g / L, electrode plate spacing of 20 mm, and input voltage of 9.12 V. Under these conditions, the relationship between cadmium removal rate and time at different pH values ​​was investigated. The experimental results are shown in Figure 31as shown in Figure (b). The experimental results show that the removal efficiency is the highest when the pH value is 4. This is because when the acidity of the solution is strong, the content of H + in the solution is high, the overpotential of hydrogen evolution caused by concentration polarization is low, and the ability of hydrogen evolution is strong, which forms a competitive effect with the precipitation of Cd 2+ . Therefore, the lower the pH value, the lower the removal rate of Cd. When the pH value is 5, although the competition between hydrogen evolution and Cd 2+ precipitation weakens, the hydrolysis degree of cadmium increases, so the removal efficiency of cadmium decreases.

[0142] Figure 31 Figure (c) explored the relationship between the removal rate of Cd and time at different spacings between the anode ruthenium-iridium-titanium electrode and the titanium plate cathode under the experimental conditions of a solution concentration of 3 g / L and a pH value of 4. Through the experimental results, it can be found that when the distance between the two electrode plates is 20 mm, the best removal rate can reach 77.2%. At this time, because the distance between the electrode plates is appropriate at 20 mm, the electric field is uniform and the ion migration efficiency is high.

[0143] The comparison of the removal performances of other lead ions, copper ions and cadmium ions with the present invention is shown in Table 1. It can be seen that the electro-deposition driven by the triboelectric nanogenerator for removing lead ions in the present invention can be comparable to the existing traditional lead ion removal methods, such as chemical precipitation, adsorption and bio-adsorption. From this comparison table, it can be proved that it is feasible to use the triboelectric nanogenerator as a power source for removing lead ions and it has application value in removing heavy metal ions. As a power source, the triboelectric nanogenerator has the advantages of energy conservation, environmental protection, high energy efficiency and low cost, and electro-deposits and removes heavy metal ions while collecting environmental energy. This method has broad application prospects and provides new ideas and methods for removing heavy metal ions.

[0144] Table 1 Comparison of the removal performances of other ions with the present invention

[0145]

[0146] Conclusion: The present invention mainly starts from the PMM circuit and builds a heavy metal ion removal platform based on the triboelectric nanogenerator. The PMM circuit combines the switching circuit and the maximum power tracking module to control the output circuit ripple within 0.01 V and the output voltage is 9.12 V. This voltage is sufficient to drive the removal of heavy metal ions. At the same time, a heavy metal ion removal platform is built, and further research is carried out on Cu 2+ , Pb 2+ and Cd 2+A detailed discussion was carried out in terms of different concentrations, different pH values, and different electrode plate spacings. The experiment shows that as the reaction time increases, the removal effects of the three ions show an increasing trend. The experiment comprehensively considered the effects of the initial concentration, pH value, and electrode spacing of the solution on the experiment. The results show that under the optimal conditions, the removal rate of Cu 2+ can reach up to 80%, and the removal rate of Pb 2 + can reach 86.90%, and the removal rate of Cd 2+ can reach 77.20%. This fully demonstrates the feasibility of the triboelectric nanogenerator in the field of electrodeposition and provides new research ideas for future development.

Claims

1. A triboelectric nanogenerator for fluid energy harvesting, characterized in that, Comprising: A base, a plurality of support plates, a force-receiving turbine blade, a rotating shaft, a contact separation assembly, and a sliding friction assembly; The support plates are fixedly installed on both sides of the base. Bearings are respectively embedded at the tops of the support plates. The rotating shaft is rotatably connected to the support plates through the bearings. The force-receiving turbine blade includes a mounting portion and a plurality of blades. The plurality of blades are fixedly connected to the outer periphery of the mounting portion. The force-receiving turbine blade is fixedly installed at one end of the rotating shaft through the mounting portion. The contact separation assembly and the sliding friction assembly are respectively installed on the rotating shaft; The contact separation assembly includes a first rotor embedded with a plurality of universal balls, a balloon film, a fixed disk provided with a plurality of embedding holes, a plurality of copper electrodes coated with an Ecoflex / ZnS film, a plurality of copper electrodes covered with a sponge film, a gasket, a first stator, and a first bracket and a second bracket. The gasket and the copper electrode covered with the sponge film are respectively fixedly connected to the first stator. The thickness of the gasket is greater than the thickness of the copper electrode covered with the sponge film. The copper electrode coated with the Ecoflex / ZnS film is embedded in the embedding hole of the fixed disk. The Ecoflex / ZnS film is close to the sponge film. The balloon film covers the surface of the fixed disk. The universal balls are in close contact with the balloon film; A through hole is provided at the centers of the first rotor, the balloon film, the fixed disk, and the first stator. The rotating shaft passes through the through hole at the center of the first rotor and is fixedly connected to the first rotor. The rotating shaft sequentially passes through the through holes of the balloon film, the fixed disk, and the first stator. The diameters of the through holes of the balloon film, the fixed disk, and the first stator are greater than the diameter of the rotating shaft. The first stator is fixedly installed on the first bracket. The fixed disk is fixedly installed on the second bracket. The first bracket and the second bracket are respectively fixedly installed on the base; The sliding friction assembly includes a second rotor, a second stator, and a third bracket. The main bodies of the second rotor and the second stator are PCBs. Grid-shaped copper electrodes are uniformly provided on the second rotor and the second stator. A PTFE layer is pasted on the copper electrode of the second rotor. A GF film is pasted on the copper electrode of the second stator. The PTFE layer and the GF film are in close contact; A through hole is provided at the center of the second rotor and the center of the second stator. The rotating shaft passes through the through hole of the second rotor and is fixedly connected to the second rotor. The rotating shaft passes through the through hole of the second stator. The diameter of the through hole of the second stator is greater than the diameter of the rotating shaft. The second stator is fixedly installed on the third bracket. The third bracket is fixedly installed on the base.

2. The triboelectric nanogenerator for fluid energy harvesting according to claim 1, wherein The shape of Rotor 1 is a circle with a diameter of 200 mm, a through-hole with a diameter of 6 mm is provided at the center, the material is acrylic, and the thickness is 12 mm; the diameter of the universal ball is 18 mm, the material is bearing steel, and the height of the universal ball protruding from Rotor 1 is 5 mm; the shape of the balloon film is a circle with a diameter of 200 mm, a through-hole with a diameter of 8 mm is provided at the center, the material is latex, and the thickness is 0.04 mm; the shape of the fixed disk is a circle with a diameter of 200 mm, a through-hole with a diameter of 8 mm is provided at the center, the material is acrylic, and the thickness is 4 mm. The shape of the embedding holes is multiple squares with a side length of 5 cm; the shape of the copper electrodes coated with Ecoflex / ZnS film is multiple squares with a side length of 5 cm. Among them, the thickness of the copper electrode layer is 0.065 mm, and the thickness of the Ecoflex / ZnS film is 0.1 mm; the shape of the copper electrodes covered with sponge film is multiple squares with a side length of 5 cm. Among them, the thickness of the copper electrode layer is 0.065 mm, and the thickness of the sponge film is 0.5 mm; the shape of the gasket is a strip, the material is acrylic, and the thickness is 5 mm; the shape of Stator 1 is a circle with a diameter of 200 mm, a through-hole with a diameter of 8 mm is provided at the center, the material is acrylic, and the thickness is 5 mm; when the universal ball does not rotate into the embedding hole, the distance between the sponge film and the Ecoflex / ZnS film is 5 mm, and the positions of multiple copper electrodes coated with Ecoflex / ZnS film and multiple copper electrodes covered with sponge film correspond one by one. When the universal ball rotates into the embedding hole, the positions of multiple universal balls and multiple embedding holes correspond one by one.

3. The triboelectric nanogenerator for fluid energy harvesting according to claim 1, wherein The shape of Rotor 2 is a circle with a diameter of 200 mm, a through-hole with a diameter of 6 mm is provided at the center. The copper electrodes on Rotor 2 are arranged in a ring with an outer diameter of 200 mm and an inner diameter of 70 mm centered on the center of Rotor 2, and the number of grids is 30 and they are evenly distributed; the shape of Stator 2 is a square with a side length of 200 mm, a through-hole with a diameter of 8 mm is provided at the center. The copper electrodes on the stator are arranged in a ring with an outer diameter of 200 mm and an inner diameter of 70 mm centered on the center of Stator 2, and the number of grid pairs is 30 and they are evenly distributed. One grid is extended on each side of the copper electrodes on the stator as a terminal.

4. The triboelectric nanogenerator for fluid energy harvesting according to claim 1, wherein The thickness of the PTFE layer is 0.01 mm, the shape of the PTFE layer is the same as that of Rotor 2, and it completely covers Rotor 2 when pasted; the thickness of the GF film is 0.15 mm, the shape of the GF film is the same as that of Stator 2, and it completely covers Stator 2 when pasted.

5. The triboelectric nanogenerator for fluid energy harvesting according to claim 1, wherein The base, support plate, Bracket 1, Bracket 2 and Bracket 3 are all made of wood. The size of the base is 35 cm in length and 20 cm in width. The support plate is trapezoidal, with a lower base length of 14 cm, an upper base length of 5 cm, and a height of 14 cm. Stator 1 is embedded on Bracket 1, the fixed disk is embedded on Bracket 2. The height of Bracket 1 and Bracket 2 is 140 mm, and the width is 200 mm. Stator 2 is embedded on Bracket 3, and the height of Bracket 3 is 140 mm, and the width is 220 mm. The length of the rotating shaft is 305 mm, the diameter is 5 mm, and the material is carbon steel.

6. A preparation method of a triboelectric nanogenerator for fluid energy harvesting, characterized in that, Including the following steps: (1)Fabricate a copper electrode coated with an Ecoflex / ZnS thin film: Add ZnS powder to Ecoflex silicone and stir to obtain a homogeneous mixture. Uniformly coat the obtained mixture on the surface of a wooden board on which a copper electrode has been pre-laid. Transfer the coated sample to a vacuum drying oven for curing treatment to obtain a copper electrode coated with an Ecoflex / ZnS thin film; (2)Install according to the structure of the triboelectric nanogenerator for fluid energy harvesting described in any one of claims 1-5 to obtain the present product.

7. The preparation method of a triboelectric nanogenerator for fluid energy harvesting according to claim 6, wherein, In step (1), the ZnS powder accounts for 0-13 wt% of the total mass of the ZnS powder and Ecoflex silicone, the coating thickness is 0.1 mm, the curing treatment temperature is 60 °C, and the curing treatment time is 4 h.

8. The preparation method of a triboelectric nanogenerator for fluid energy harvesting according to claim 6, characterized in that, In step (1), the obtained mixture is uniformly coated on the surface of a wooden board on which a copper electrode has been pre-laid by spin coating at a rotation speed of 1000 r / min.

9. Application of the triboelectric nanogenerator for fluid energy harvesting described in any one of claims 1-5 in the removal of heavy metal ions.

10. Application of the triboelectric nanogenerator for fluid energy harvesting in heavy metal ion removal according to claim 9, characterized in that, Constructing an Electroplating System for Removing Cu by a Triboelectric Nanogenerator with Fluid Energy Harvesting 2+ , Pb 2+ and Cd 2+ .

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