Self-powered heavy metal sensing device

Abstract

A self-powered heavy metal sensing device comprises: a friction material electrode layer, a friction material dielectric layer, and an external circuit, wherein the friction material electrode layer comprises a first substrate, a first electrode layer, and a heavy metal sensing layer, the friction material dielectric layer comprises a second substrate, a second electrode layer, and a dielectric response layer, and the friction material electrode layer and the friction material dielectric layer are spaced apart from each other with the heavy metal sensing layer oriented towards the dielectric response layer. The external circuit is connected to the first electrode layer and the second electrode layer, wherein the heavy metal sensing layer is a deprotonated polydiaminonaphthalene layer formed by mixing diaminonaphthalene and an ammonium sulfate solution, and a power generation current is generated in the external circuit by means of the contact initiation and the static sensing between the friction material electrode layer and the friction material dielectric layer, thereby sensing the heavy metal ions by means of the heavy metal sensing layer.

Description

Technical Field

[0001] This invention relates to a heavy metal sensing device, and more particularly to a self-powered heavy metal sensing device. Prior Technology

[0002] With the rapid development of modern industry and the continuous improvement of living standards and technological conditions, many industrial sectors, such as metal electroplating, mineral mining, fertilizer manufacturing, battery production, papermaking, and pesticides, discharge large amounts of wastewater containing various heavy metal ions. The presence of these heavy metal ions causes serious pollution to the surrounding ecological environment. Compared to organic pollutants, heavy metal ions degrade more slowly in organisms and tend to accumulate, entering the human body through the food chain. Many heavy metals are toxic or carcinogenic, posing a significant threat to human health. Therefore, monitoring the content of heavy metal ions in industrial wastewater has become crucial.

[0003] Currently, heavy metal ion analysis techniques mainly include inductively coupled plasma atomic emission spectrometry (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), X-ray fluorescence spectrometry (XRF), chemical precipitation, reverse osmosis, ion exchange, and membrane filtration. However, these techniques suffer from drawbacks such as complex and expensive equipment, cumbersome and time-consuming operating procedures, high energy consumption, unsuitability for on-site analysis, the need for specially trained personnel, and dependence on external power sources.

[0004] To address the aforementioned issues, researchers have focused on developing self-powered devices utilizing energy sources such as mechanical energy, wind energy, wave energy, solar energy, and thermal energy. Among these, triboelectric nanogenerator (TENG) technology, based on the triboelectric effect and electrostatic induction, has attracted significant attention. TENGs can convert mechanical energy into electrical energy, offering advantages such as high power generation, diverse material selection, simple structure, and low manufacturing cost. However, in heavy metal sensing applications, this technology still faces challenges including time-consuming and complex component material manufacturing processes, low component output performance, no significant improvement in output performance after sensing, and the use of molecules that could pollute the environment. Summary of the Invention

[0005] Therefore, the object of the present invention is to provide a self-powered heavy metal sensing device to solve the problems of the prior art.

[0006] The present invention provides a self-powered heavy metal sensing device to solve the problems of prior art. The device includes: a triboelectric material electrode layer comprising a first substrate, a first electrode layer formed on the first substrate, and a heavy metal sensing layer formed on the first electrode layer; a triboelectric material dielectric layer comprising a second substrate, a second electrode layer formed on the second substrate, and a dielectric reaction layer formed on the second electrode layer, wherein the triboelectric material electrode layer and the triboelectric material dielectric layer are disposed facing each other at intervals with the heavy metal sensing layer facing the dielectric reaction layer; and an external circuit connected between the first electrode layer and the second electrode layer. The heavy metal sensing layer is a deprotonated poly(1,5-diaminonaphthalene), PDAN layer, which is composed of diaminonaphthalene (DAN) and ammonium persulfate. The friction material is generated by mixing APS solution, and the contact between the electrode layer and the dielectric layer of the friction material generates electricity and electrostatic induction, which generates current in the external circuit. The heavy metal sensing layer reacts with heavy metal ions, including lead ions, to sense heavy metal ions.

[0007] In one embodiment of the present invention, a self-powered heavy metal sensing device is provided, wherein the polydiaminonaphthalene layer is prepared by mixing a 0.1 M diaminonaphthalene and acetonitrile (ACN) mixed solution and an ammonium sulfate aqueous solution in equal proportions, coating the mixture, annealing it at 140 °C for 10 minutes, then allowing the reaction to continue at 25 °C for 50 minutes, followed by rinsing with deionized water and acetonitrile at 3000 rpm / 60 s, then deprotonating it with 1 M NH4OH solution at 3000 rpm / 60 s, and finally rinsing the polydiaminonaphthalene layer with deionized water at 3000 rpm / 60 s.

[0008] In one embodiment of the present invention, a self-powered heavy metal sensing device is provided, wherein the first substrate and the second substrate are glass substrates.

[0009] In one embodiment of the present invention, a self-powered heavy metal sensing device is provided, wherein the dielectric reaction layer is a polydimethylsiloxane (PDMS) layer.

[0010] In one embodiment of the present invention, a self-powered heavy metal sensing device is provided, wherein the first electrode layer, the second electrode layer and the dielectric reaction layer are poly(1,5-diaminonaphthalene), PDAN layers.

[0011] In one embodiment of the present invention, a self-powered heavy metal sensing device is provided, wherein the first electrode layer and the second electrode layer are indium tin oxide (ITO) electrode layers.

[0012] In the self-powered heavy metal sensing device of the present invention, a polydiaminonaphthalene conductive polymer with properties such as non-volatileness, water resistance, acid resistance, alkali resistance and environmental harmlessness is used as a heavy metal sensing layer to sense heavy metal ions in wastewater. Furthermore, the polydiaminonaphthalene layer can be easily and quickly generated by a solution-state process of mixing diaminonaphthalene and ammonium sulfate solution, and the conductivity of the polydiaminonaphthalene layer can be improved. This provides a self-powered heavy metal sensing device with simple and fast manufacturing process, high component output performance and no environmental pollution. Simple Explanation of the Diagram

[0013] Figure 1 is a schematic diagram illustrating a self-powered heavy metal sensing device according to an embodiment of the present invention; Figure 2 is a schematic diagram illustrating the interaction between Pb²⁺ heavy metal ions and polydiaminonaphthalene; Figure 3 illustrates the open-circuit voltage (VOC) of Pb²⁺ sensed by the self-powered heavy metal sensing device according to the present invention. Figure 4 illustrates the VOC of Pb²⁺ sensed by the self-powered heavy metal sensing device according to the present invention. Figure 5 illustrates the VOC of Pb²⁺ sensed by the self-powered heavy metal sensing device according to the present invention. Figure 6 shows the response of the self-powered heavy metal sensing device according to the present invention to sense Pb²⁺; Figure 7 shows the results of KPFM analysis of the self-powered heavy metal sensing device according to the present invention; Figure 8 shows the surface morphology analysis results of the heavy metal sensing layer of the self-powered heavy metal sensing device according to the present invention. Implementation

[0014] The embodiments of the present invention will be described below with reference to Figures 1 to 8. This description is not intended to limit the embodiments of the present invention, but rather to illustrate one example of the present invention.

[0015] As shown in Figure 1, a self-powered heavy metal sensing device 100 according to an embodiment of the present invention includes: a friction material electrode layer 10, including a first substrate 11, a first electrode layer 12 formed on the first substrate 11, and a heavy metal sensing layer 13 formed on the first electrode layer 12; a friction material dielectric layer 20, including a second substrate 21, a second electrode layer 22 formed on the second substrate 21, and a dielectric reaction layer 23 formed on the second electrode layer 22, wherein the friction material electrode layer 10 and the friction material dielectric layer 20 are disposed facing each other at intervals with the heavy metal sensing layer 13 facing the dielectric reaction layer 23; and an external circuit 30, the circuit being connected between the first electrode layer 12 and the second electrode layer 22, wherein the heavy metal sensing layer 13 is a deprotonated poly(1,5-diaminonaphthalene), PDAN layer, and the poly(1,5-diaminonaphthalene), PDAN layer is composed of diaminonaphthalene (DAN) and ammonium persulfate. The friction material is generated by mixing APS solution. Through the contact electrification and electrostatic induction between the friction material electrode layer 10 and the friction material dielectric layer 20, a power generation current is generated in the external circuit 30. The heavy metal sensing layer 13 reacts with heavy metal ions, including lead ions, to sense heavy metal ions.

[0016] In detail, this invention applies a triboelectric nanogenerator (TENG) to the field of heavy metal ion (including lead ion) sensing devices. The TENG works by combining contact electrification and electrostatic induction to convert mechanical energy into electrical energy. When two friction materials come into contact, electron transfer occurs at the interface due to differences in electron affinity (EA). The induced electrostatic charge varies depending on the distance between the two friction materials, and the electrons flow through the external circuit to generate a current output.

[0017] Polydiaminonaphthalene possesses properties such as non-volatileness, water resistance, acid and alkali resistance, and environmental friendliness. Furthermore, as shown in Figure 2, the electron-donating groups (amino groups, C-NH₂) and imine groups (C-NH-C and CN=C) on the polydiaminonaphthalene chain enable heavy metal ions to interact with the lone pair electrons of the nitrogen atoms between the amino and imine groups in the polydiaminonaphthalene molecule, forming a six-membered ring chelate structure. This allows heavy metal ions to remain stably within the polydiaminonaphthalene molecules, resulting in a mechanism that gives polydiaminonaphthalene excellent adsorption performance for heavy metal ions.

[0018] In detail, in this invention, the polydiaminonaphthalene layer is prepared by mixing 0.1 M diaminonaphthalene with acetonitrile (ACN) and an aqueous solution of ammonium sulfate in equal proportions, coating the mixture, annealing at 140 °C for 10 minutes, then allowing the reaction to continue at 25 °C for 50 minutes, followed by rinsing with deionized water and acetonitrile at 3000 rpm / 60 s, then deprotonating with 1 M NH4OH solution at 3000 rpm / 60 s, and finally rinsing with deionized water at 3000 rpm / 60 s. This method is also referred to below as solution-state polymerization film formation.

[0019] In the self-powered heavy metal sensing device 100 according to the present invention, the polydiaminonaphthalene layer is formed by solution polymerization, which has the advantages of simple and fast production, low cost and applicability to large-area processes.

[0020] Specifically, in the self-powered heavy metal sensing device 100 according to an embodiment of the present invention, the first substrate 11 and the second substrate 21 are glass substrates.

[0021] In the self-powered heavy metal sensing device 100 according to the present invention, the polydiaminonaphthalene layer is formed by solution polymerization, unlike metal materials which require high-temperature vapor deposition to make thin films, and therefore can be applied to various substrates such as flexible plastic sheets.

[0022] Furthermore, in the self-powered heavy metal sensing device 100 according to an embodiment of the present invention, the dielectric reaction layer 23 is a polydimethylsiloxane (PDMS) layer. Furthermore, the first electrode layer 12 and the second electrode layer 22 are indium tin oxide (ITO) electrode layers.

[0023] Generally, the dielectric reactive layer is made of a material with high electron affinity to receive the negative charge generated by electrode friction. The conductive electrodes generate positive charge through induction and act as channels for charge transfer. The external circuit acts as a bridge for charge transfer, drawing electrons from the electrodes to generate a reverse current.

[0024] In one embodiment, the dielectric reactive layer 23 is prepared by mixing a PDMS precursor and a curing agent in a weight percentage ratio of 13:1, dissolving them in chlorobenzene, and stirring for one hour to obtain a PDMS solution. Next, the PDMS solution is spin-coated onto an ITO electrode substrate at 1800 rpm / 90 s and annealed at 100 °C for 60 minutes to obtain the PDMS dielectric layer.

[0025] Of course, the present invention is not limited thereto. In the self-powered heavy metal sensing device 100 according to an embodiment of the present invention, the first electrode layer 12, the second electrode layer 22 and the dielectric reaction layer 23 are poly(1,5-diaminonaphthalene), PDAN layers. In this way, the self-powered heavy metal sensing device 100 according to the present invention becomes a heavy metal sensor of all poly(1,5-diaminonaphthalene).

[0026] The following describes the experiment on the sensing of heavy metal ions by polydiaminonaphthalene.

[0027] First, a protonated polydiaminonaphthalene layer was fabricated as the heavy metal sensing layer in a self-powered heavy metal sensing device. Specifically, a 0.1 M DAN / ACN mixed solution and an APS aqueous solution were prepared, mixed in equal proportions, and spin-coated onto an ITO glass substrate. The mixture was then annealed at 140 °C for 10 minutes, followed by a reaction at 25 °C for 50 minutes. Subsequently, the substrate was rinsed with DI water and ACN at 3000 rpm for 60 s to remove excess unreacted material. This completed the protonated polydiaminonaphthalene heavy metal sensing layer.

[0028] The heavy metal ion sensing experiment was conducted by using 800 μl of Pb(NO3)2 aqueous solution on the polydiaminonaphthalene heavy metal sensing layer and reacting it at 25 °C for 1 hour. Subsequently, the solution was removed at 3000 rpm / 60 s, and the layer was rinsed with DI water at 3000 rpm / 60 s to remove Pb2+ ions that were not chelated in the polydiaminonaphthalene structure.

[0029] As shown in Figure 3, the self-powered heavy metal sensing device with a protonated polydiaminonaphthalene layer showed no significant difference in open-circuit voltage (VOC) before and after Pb²⁺ heavy metal ion sensing. It is noteworthy that this was achieved by increasing the Pb²⁺ aqueous solution to 1 M, a concentration more than 1000 times higher than the detection limit of most conventional self-powered heavy metal sensors. This demonstrates that elements using polydiaminonaphthalene cannot sense heavy metal ions as self-powered devices without deprotonation.

[0030] Therefore, the inventors used the deprotonated polydiaminonaphthalene layer as the heavy metal sensing layer in the self-powered heavy metal sensing device, and conducted heavy metal ion sensing experiments in the same manner.

[0031] As shown in Figure 4, the open-circuit voltage (VOC) of sensing 1000 μM Pb 2+ increases from 252 V to 432 V.

[0032] Table 1 below summarizes the open-circuit voltage and responsivity of a self-powered heavy metal sensing device 100 according to an embodiment of the present invention for sensing lead ions by means of a deprotonated polydiaminonaphthalene layer.

[0033] Table 1. Lead ion concentration [μM] Open circuit voltage (Volt) responsiveness 0 250 ± 2 (252) 0 ± 0.008 25 274 ± 2 (276) 0.096 ± 0.008 50 290 ± 2 (292) 0.160 ± 0.008 100 338 ± 6 (344) 0.352 ± 0.024 150 386 ± 6 (392) 0.544 ± 0.020 200 416 ± 4 (420) 0.664 ± 0.016

[0034] As shown in Figure 5 and Table 1, the output of the self-powered heavy metal sensing device 100 increases significantly with the increase of Pb2+ concentration, and can reach a maximum open-circuit voltage of 420 V at 200 μM with an initial open-circuit voltage of 252 V.

Mathematical Formula 1

[0035] Formula 1 is the formula for responsivity, where V0 is the initial VOC of the element, and V' is the VOC after sensing by the element. After calculation, the responsivity in Table 1 can be obtained, and plotting the responsivity against the Pb2+ ion concentration yields Figure 6. From Figure 6, the effectiveness of the self-powered heavy metal sensing device of the present invention in sensing Pb2+ can be seen. The linear range of the self-powered heavy metal sensing device of the present invention is 25-200 μM, and the sensitivity is 0.0033 μM-1.

[0036] Furthermore, since the greater the difference in surface work function (WF) between the electrode layer and the dielectric layer, the higher the TENG output will be, KPFM analysis was performed on the self-powered heavy metal sensing device of the present invention before and after sensing Pb 2+.

[0037] Table 2 below summarizes the conductivity measurement results of the self-powered heavy metal sensing device 100 after sensing Pb 2+ according to an embodiment of the present invention, wherein the values ​​in parentheses are the highest values.

[0038] Table 2. Lead ion concentration [μM] Open circuit voltage (Volt) Thickness (nm) Conductivity (S / cm) 0 250 ± 2 (252) 278.5 ± 22.5 (301.5) 1858.242 ± 120 (1978.424) 50 290 ± 2 (292) 2477.663 ± 211 (2677.663) 100 338 ± 6 (344) 2697.639 ± 165 (2862.639) 200 416 ± 4 (420) 2880.773 ± 137 (3017.773)

[0039] Figure 7 shows the KPFM analysis of the self-powered heavy metal sensing device according to the present invention, wherein (a) shows the results of the PDMS dielectric reaction layer, (b) shows the results of the PDAN heavy metal sensing layer, (c) shows the results of the deprotonated PDAN heavy metal sensing layer, and (d) shows the results of the deprotonated PDAN heavy metal sensing layer sensing 1000 μM Pb 2+.

[0040] As shown in Figure 7, the WF of the PDMS dielectric reactive layer is 5.40 eV. The WF of the PDAN heavy metal sensing layer is 3.85 eV, while the WF of the heavy metal sensing layer after deprotonation treatment increases to 4.01 eV, thus causing the output of triboelectric nano-generation to decrease from VOC of 360 V to 250 V. As can be seen from Figure 7(d), after sensing 1000 μM Pb 2+, the WF decreases to 3.97 eV.

[0041] Furthermore, the conductivity tests in Table 2 show that conductivity increases with increasing Pb²⁺ concentration. Based on these results, it can be inferred that when Pb²⁺ chelates into the PDAN structure, it not only reduces the WF of the PDAN film but also increases the WF difference with the PDMS dielectric reactive layer. In addition, the increased conductivity also reduces the internal resistance of the device, thus reducing performance loss. Therefore, sensing Pb²⁺ improves the triboelectric nano-power generation efficiency.

[0042] Figure 8 is a SEM image showing the surface morphology analysis of the heavy metal sensing layer of the self-powered heavy metal sensing device according to the present invention, wherein (a) shows the SEM image before sensing Pb 2+, and (b) shows the SEM image after sensing Pb 2+.

[0043] As shown in the SEM measurement results of Figure 8(a) and (b), it can be observed that the heavy metal sensing layer of the self-powered heavy metal sensing device according to the present invention has a plurality of circular pore structures. The inventors believe that this structure is advantageous for the PDAN to capture Pb2+ into the structure. Furthermore, a comparison of Figure 8(a) and (b) also reveals that there is no significant difference in the configuration of the thin film before and after sensing.

[0044] By means of the technical means adopted in this invention, the self-powered heavy metal sensing device 100 of this invention utilizes polydiaminonaphthalene conductive polymer, which has properties such as non-volatileness, water resistance, acid resistance, alkali resistance and environmental harmlessness, as the heavy metal sensing layer 13 to sense heavy metal ions in wastewater. In the self-powered heavy metal sensing device 100 of this invention, the polydiaminonaphthalene layer can be easily and quickly generated by a solution process of mixing diaminonaphthalene and ammonium sulfate solution, and the conductivity of the polydiaminonaphthalene layer can be improved. Thus, a self-powered heavy metal sensing device 100 with simple and fast process, high component output performance and no environmental pollution is provided.

[0045] The above description and explanation are merely illustrative of preferred embodiments of the present invention. Those skilled in the art may make other modifications based on the following defined scope of the patent application and the above description, but such modifications should still be within the spirit of the invention and the scope of the invention.

[0046] 100: Self-powered heavy metal sensing device 10: Friction material electrode layer 11: First substrate 12: First electrode layer 13: Heavy metal sensing layer 20: Dielectric layer of triboelectric material 21: Second substrate 22: Second electrode layer 23: Dielectric reactive layer 30: External Circuit

Claims

1. A self-powered heavy metal sensing device, comprising: a tribological electrode layer including a first substrate, a first electrode layer formed on the first substrate, and a heavy metal sensing layer formed on the first electrode layer; a tribological dielectric layer including a second substrate, a second electrode layer formed on the second substrate, and a dielectric reactive layer formed on the second electrode layer, wherein the tribological electrode layer and the tribological dielectric layer are disposed facing each other at intervals with the heavy metal sensing layer facing the dielectric reactive layer; and an external circuit connected between the first electrode layer and the second electrode layer, wherein... The heavy metal sensing layer is a deprotonated poly(1,5-diaminonaphthalene), PDAN layer, which is formed by mixing diaminonaphthalene (DAN) and ammonium persulfate (APS) solution. Through the contact electrification and electrostatic induction between the friction material electrode layer and the friction material dielectric layer, a power generation current is generated in the external circuit. The heavy metal sensing layer reacts with heavy metal ions, including lead ions, to sense heavy metal ions.

2. The self-powered heavy metal sensing device as described in claim 1, wherein the polydiaminonaphthalene layer is prepared by mixing a 0.1 M diaminonaphthalene and acetonitrile (ACN) mixed solution and an ammonium sulfate aqueous solution in equal proportions, coating the mixture, annealing it at 140 °C for 10 minutes, then allowing the reaction to continue at 25 °C for 50 minutes, followed by rinsing with deionized water and acetonitrile at 3000 rpm / 60 s, then deprotonating it with 1 M NH4OH solution at 3000 rpm / 60 s, and finally rinsing the polydiaminonaphthalene layer with deionized water at 3000 rpm / 60 s.

3. The self-powered heavy metal sensing device as described in claim 1, wherein the first substrate and the second substrate are glass substrates.

4. The self-powered heavy metal sensing device as described in any one of claims 1 to 3, wherein the dielectric reactive layer is a polydimethylsiloxane (PDMS) layer.

5. The self-powered heavy metal sensing device as described in any one of claims 1 to 3, wherein the first electrode layer, the second electrode layer and the dielectric reactive layer are poly(1,5-diaminonaphthalene), PDAN layers.

6. The self-powered heavy metal sensing device as described in any one of claims 1 to 3, wherein the first electrode layer and the second electrode layer are indium tin oxide (ITO) electrode layers.

7. The self-powered heavy metal sensing device as described in claim 4, wherein the first electrode layer and the second electrode layer are indium tin oxide (ITO) electrode layers.

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