Method for removing pollutants by means of a body effect solid-liquid contact electrocatalysis

Abstract

The present application belongs to the technical field of pollutant treatment, and particularly relates to a method for removing pollutants by body effect solid-liquid contact electrocatalysis. The present application couples friction catalysis with contact electrocatalysis (CEC), constructs a friction contact electrocatalysis (TCE) device, and introduces an excitation charge to optimize a high-performance excitation condition to obtain a friction contact electrocatalysis (E-TCE) device under the condition, so as to realize self-powered efficient degradation of CV dyes. The E-TCE device takes polytetrafluoroethylene (PTFE) as a friction medium layer, relies on the body effect to expand the charge transmission from the film surface to the film interior, and then regulates and controls the charge storage and output through a rectification energy storage module, so as to solve the problems of disordered charge direction and easy loss without excitation.

Description

Technical Field

[0001] This invention belongs to the field of pollutant treatment technology, specifically relating to a method for bulk effect solid-liquid contact electrocatalytic removal of pollutants. Background Technology

[0002] Dyeing and printing wastewater, due to its complex composition, high organic matter concentration, deep color, and poor biodegradability, has become a key target in the field of industrial wastewater treatment. Dye molecules, in particular, can significantly alter water color even at extremely low concentrations of 0.1–10 mg / L, damaging the light transmittance of aquatic ecosystems, inhibiting photosynthesis in aquatic plants, and posing a potential threat to aquatic organisms and human health (such as liver and kidney damage) through the food chain. Among commonly used dyes in textile dyeing and printing, crystal violet (CV), as a typical aniline-derived triphenylmethane cationic dye, is widely used in the dyeing processes of wool, silk, and other fabrics due to its excellent dyeing effect and low cost. However, CV has significant biotoxicity, causing skin and eye irritation, and long-term exposure may lead to kidney failure. It also has significant toxic effects on mammalian cells, making it a persistent and difficult-to-degrade pollutant in dyeing and printing wastewater that urgently needs removal. Therefore, developing efficient remediation technologies for CV and other dyes in wastewater is of great practical significance for purifying the water environment and protecting the ecosystem and human health.

[0003] Currently, the main technologies for treating dye pollutants in dyeing and printing wastewater include physical, chemical, and biological methods: Physical methods (such as adsorption and membrane separation) can quickly achieve solid-liquid separation of dyes, but they only complete the phase transfer of pollutants, requiring further treatment and easily causing secondary pollution, and it is difficult to achieve complete mineralization of dye molecules; Biological methods (such as activated sludge process and microbial degradation) rely on the metabolic decomposition of dyes by microorganisms. Although the cost is low, the degradation efficiency for recalcitrant dyes such as CV with stable structures and conjugated benzene rings is less than 15%, and the reaction cycle is as long as 24-72 hours. At the same time, the activity of microorganisms is easily inhibited by environmental factors such as wastewater pH and salinity, limiting their applicability; Chemical oxidation methods (such as Fenton oxidation and ozone oxidation) can destroy the structure of dye molecules by generating highly oxidizing active species, but they have problems such as high cost and the generation of toxic intermediates in some processes. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments.

[0005] As one aspect of the present invention, the present invention provides a method for bulk effect solid-liquid contact electrocatalytic removal of pollutants, which includes the following steps: (1) Constructing a triboelectric contact electrocatalytic component with a bulk effect structure: Using an insulating substrate (1) as a support, a bottom electrode (2) is set on the substrate, a dielectric layer (3) is fixed on the bottom electrode (2), and a top electrode (4) is set on the top of the dielectric layer (3); the bottom electrode (2) and the top electrode (4) are connected by conductive wires to form a closed loop, thereby obtaining a triboelectric contact electrocatalytic component; (2) Constructing a charge excitation and regulation module: A bridge rectifier circuit is built using diodes as the rectifier unit. The rectifier unit and the energy storage unit are connected in series and then connected to the closed loop to obtain a bulk effect solid-liquid contact electrocatalytic system. (3) Bulk effect solid-liquid catalysis: The droplets containing pollutants are driven by gravity to flow along the surface of the dielectric layer. Active species are generated by the interfacial charge transfer that occurs when the droplets come into contact with the dielectric layer. At the same time, the triboelectric signal generated by the triboelectric contact electrocatalytic component is rectified and stored by the charge excitation and regulation module to form a directional and stable current output. This current extends the charge transfer from the surface of the dielectric layer to the interior of the dielectric layer, further promoting the interfacial charge transfer and the generation of active species, thereby achieving the removal of pollutants in the water.

[0006] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants method of the present invention: the dielectric layer in step (1) is a polymer film, and the polymer film is one of polytetrafluoroethylene, polyimide, polyethylene terephthalate, polypropylene or polyethylene.

[0007] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants method of the present invention: the dielectric layer in step (1) includes a polytetrafluoroethylene film.

[0008] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants method of the present invention: the insulating substrate in step (1) is a PMMA organic glass plate, the bottom electrode is a double-sided copper tape, and the top electrode is a single-sided copper tape.

[0009] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants method of the present invention: the energy storage unit in step (2) is a capacitor.

[0010] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants method described in this invention: the bridge rectifier circuit in step (2) is built on a breadboard, and the diode model includes 1N4007.

[0011] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants method of the present invention: the active species in step (3) include hydroxyl radicals and superoxide anion radicals.

[0012] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal method for pollutants described in this invention: the frictional contact between the droplet and the dielectric layer in step (3) controls the pollutant removal efficiency by adjusting the droplet's falling height, the tilt angle of the dielectric layer, the thickness of the dielectric layer, the capacity of the energy storage unit, and / or the initial concentration of the pollutants.

[0013] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal method for pollutants according to the present invention: the droplet falling height is 10~25 cm, the tilt angle of the dielectric layer is 30°~75°, the thickness of the dielectric layer is 0.05~0.5 mm, the capacity of the energy storage unit is 15~68 nF, and the initial concentration of the pollutant is 5~20 mg / L.

[0014] As a preferred embodiment of the bulk effect solid-liquid contact electrocatalytic removal of pollutants according to the present invention: the pollutant in step (3) is an organic dye in the dyeing and printing wastewater, and the organic dye includes crystal violet, rhodamine B, methylene blue or tetracycline.

[0015] The beneficial effects of this invention are as follows: Addressing the problems of high energy consumption and low degradation efficiency in existing methods for treating recalcitrant dyes such as crystal violet (CV) in dyeing and printing wastewater, this invention couples tribocatalysis with contact electrocatalysis (CEC) to construct a triboelectric contact electrocatalysis (TCE) device. Furthermore, by introducing excitation charge optimization, a high-performance excitation-condition triboelectric contact electrocatalysis (E-TCE) device is obtained, achieving self-powered and efficient degradation of CV dyes. The E-TCE device uses polytetrafluoroethylene (PTFE) as the triboelectric medium layer, relying on the bulk effect to extend charge transfer from the membrane surface to the membrane interior. Charge storage and output are then regulated by a rectifier energy storage module, solving the problem of disordered charge direction and easy loss without excitation. With a CV drop height of 20 cm, a PTFE membrane tilt angle of 60°, a membrane thickness of 0.1 mm, an initial CV concentration of 10 mg / L, and a capacitance of 47 nF, the E-TCE device achieves a CV degradation rate of 92.3%, which is 17% higher than the TCE device and 26% higher than the electrodeless device. The peak electrical output current reaches 8 nA, which is 140% of that of the TCE device. To clarify the degradation mechanism, quenching experiments and EPR tests confirmed that the frictional contact between the droplet and the PTFE film induced electron transfer, generating •OH and •O2. - These are the main active species in CV degradation; moreover, the device requires no external power source, and the degradation rate remains above 88% after five cycles, demonstrating excellent stability. This research highlights that the E-TCE device provides a new low-cost and green approach for the treatment of recalcitrant dyes in dyeing and printing wastewater, and has significant application value in environmental remediation and self-powered catalysis. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, wherein: Figure 1 The diagram shows the assembly of the E-TCE device, including (a) the E-TCE device diagram and a simplified schematic diagram of charge transfer at the solid-liquid interface during degradation, (b) the solid-liquid interface structure, and (c) the contact angle of the PTFE membrane.

[0017] Figure 2 This is a schematic diagram of the structure and principle of E-TCE. Among them, (a) is the circuit schematic diagram of the rectifier module, (b) is the device interface structure, and (c) is the working principle of the dual-electrode mode.

[0018] Figure 3 The study of the degradation performance of E-TCE includes: (a) a schematic diagram of the TCE device; the effects of different factors on the catalytic efficiency of the E-TCE device: (b) the distance between the separatory funnel and the membrane, (c) the tilt angle of the membrane, (d) the thickness of the membrane, (e) different capacitances, (f) different electrodes, (g) different initial CV concentrations, (h) different quenchers; and (i) repeated stability tests.

[0019] Figure 4 The current output characteristics of the E-TCE device under different factors, including (a) different capacitances, (b) distance between the separatory funnel and the membrane, (c) different angles, (d) different membrane thicknesses, (e) different initial CV concentrations, and (f) charge transfer under optimal conditions.

[0020] Figure 5 This is a schematic diagram of the degradation mechanism. Among them, (a) DMPO-•O2-, (b) DMPO•OH; (c) the process of free radical generation in the droplet and the degradation process of CV.

[0021] Figure 6 This represents a possible degradation pathway for CV in an E-TCE device.

[0022] Figure 7 For biotoxicity analysis, (a) developmental toxicity of CV and its transformation products, and (b) heatmap of acute and chronic toxicity.

[0023] Figure 8 This is a structural diagram of a TCE device.

[0024] Figure 9 The effects of different factors on catalytic efficiency are as follows: (a) the degradation effect of different types of pollutants; (b) the effect of different droplet drop frequencies on CV degradation; and (c) the effect of different polymer materials as triboelectric materials on CV degradation. Detailed Implementation

[0025] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0026] PTFE (industrial membrane, purchased from Shanghai Luyin Membrane Structure Co., Ltd.), ethanol (C2H6O, Sinopharm Group), p-benzoquinone (p-BQ, Aladdin), isopropanol (IPA, Aladdin), crystal violet (CV, Shanghai Jingkang), furfuryl alcohol (FFA, Sinopharm Group).

[0027] Assembly of the E-TCE device: The E-TCE device, based on dual-electrode tribocatalysis and contact electrocatalysis, combined with an excitation circuit, achieves efficient collection, storage, and directional transport of contact charges generated during the catalytic process. The overall structure of the device is as follows: Figure 1 As shown in a, Figure 1 The left side of diagram a is a schematic diagram of the experimental setup. Figure 1 The right side of 'a' shows the interfacial charge transfer that occurs when a droplet falls onto a PTFE membrane and comes into contact with and rubs against the membrane. Figure 1 b represents the solid-liquid interface structure. The substrate of this device is a 3×3 cm PMMA acrylic plate, and the bottom electrode uses 4×6 cm double-sided copper tape. A conductive wire connects the bottom electrode to the PMMA substrate. Industrial-grade PTFE films of different thicknesses (0.05 mm, 0.1 mm, 0.3 mm, 0.5 mm) are adhered to the surface of the bottom electrode, completely covering the copper electrode area to form a triboelectric dielectric layer. Figure 1 The hydrophobicity of the 0.1mm membrane was tested, and its contact angle was 136.5°, demonstrating excellent hydrophobicity. The top layer of the membrane, bonded with a single-sided copper tape, serves as the top electrode. A conductive wire connects the top electrode to the PTFE membrane, and the two conductive wires are connected in series with the rectifier energy storage module to form a closed loop. The charge excitation module consists of a copper electrode and a conductive wire. As the liquid droplets fall, a voltage is formed in the loop, enabling continuous charge injection and accumulation. The rectifier energy storage module consists of capacitors of different values ​​(15nF, 22nF, 47nF, 68nF) and 1N4007 diodes. The circuit is built using a 400-hole breadboard. The bridge rectifier circuit composed of multiple diodes allows current to flow in only one direction, thus converting the triboelectric signal into a unidirectional DC current. The capacitors further smooth and stabilize the current. The TCE device prepared in this invention is connected in series in this module as a switching element, which can precisely control the circuit switching between the capacitor and the diode, achieving timing regulation of energy harvesting and release. In addition, the vertical distance between the PTFE membrane and the separatory funnel was set to 10-25 cm in the experiment, and the angle between the membrane plane and the ground was 30-75°.

[0028] Characterization and electrical measurements: Measurement and acquisition of electrical signals (including current and charge) were performed using an electrometer (6451) and a data acquisition card (DAARM1651), respectively; the types of free radicals in the system were detected by paramagnetic resonance spectroscopy (EPR, EMXmicro); and the intermediate products in the CV degradation process were qualitatively and quantitatively analyzed using liquid chromatography-mass spectrometry (LC-MS, 6550 iFunnel Q-TOF).

[0029] Catalytic Activity Study: The degradation performance and catalytic activity of E-TCE for organic pollutant CV under the bulk effect were investigated by utilizing electron transfer induced by the friction of droplets falling onto the membrane surface. 10 mL of a 10 mg / L CV solution was placed in a separatory funnel and dropped dropwise onto the PTFE membrane surface at a rate of 2 drops per second from a fixed height. Electron transfer was initiated by the friction between the droplets and the membrane, thus starting the catalytic reaction. Approximately 3 mL of CV solution was collected every 10 minutes and analyzed using a UV spectrophotometer at λ... max The concentration of residual CV in the solution was determined at 578 nm. The degradation rate (%) was calculated using the following formula (Formula 1). η(%) = (1-Ct) / C0 × 100% (1) Where η represents the degradation rate of CV, C0 represents the concentration of CV before the reaction, and C t This represents the remaining CV concentration at reaction t min.

[0030] Based on the above catalytic activity tests, 1 mM IPA and BQ were added as ·OH and ·O2- scavengers, respectively, to conduct active free radical capture experiments. The presence of ROS was then tested using EPR, and ·OH and ·O2- in the reaction system were captured using DMPO.

[0031] Experimental results: The structure and principle of E-TCE: like Figure 8 As shown, the TCE device of the present invention uses a 3×3 cm PMMA organic glass plate (1) as a base, the bottom electrode (2) is made of 4×6 cm double-sided copper tape, and a conductive wire is connected to the bottom electrode. The PTFE film (3) is adhered to the surface of the bottom electrode and completely covers the copper electrode area to form a triboelectric layer. The upper layer of the PTFE film is made of copper tape as the top electrode (4), and a conductive wire is connected to the top electrode (4). The two conductive wires of the device are connected to the oscilloscope (5) and the breadboard (9) respectively to form a series circuit, wherein the first capacitor (6), the diode (7) and the second capacitor (8) on the breadboard are in series.

[0032] During the mechanically induced contact charging process at the solid-liquid interface, a large number of strong oxidizing free radicals can be generated. This provides a new technical approach for the low-cost and rapid degradation of recalcitrant pollutants in wastewater, and has significant potential for industrial application. This invention employs a charge excitation strategy, combining a rectifier energy storage module with a TCE device as a switching element. Figure 2 Figure 'a' shows the circuit diagram of the rectifier-energy storage module. The diodes utilize unidirectional conductivity to achieve rectification, guiding the pulse current generated by the TCE device unidirectionally towards the capacitor, preventing reverse charge loss. The capacitor stores the rectified charge, achieving temporary energy storage and stable output through energy accumulation. The membrane device interface structure is shown below. Figure 2 As shown in b, it consists of three parts: the bottom is a PMMA substrate; the bottom electrode is a double-sided copper electrode used for electrostatic induction, the copper electrode is connected to the industrial-grade PTFE film and the PMMA substrate; the top is a single-sided copper electrode used to collect triboelectric charge.

[0033] Figure 2 c represents the charge transfer path under the dual-electrode mode operating principle. The TCE device works in conjunction with the rectifier energy storage module. When the droplet lands on the surface of the PTFE dielectric layer, the device is in a closed state, with the top and bottom electrodes forming a closed loop through an external circuit. At this time, the contact between the PTFE dielectric layer and the droplet generates an interface charge. This charge induces equal amounts of opposite charges on the bottom and top electrodes through electrostatic induction. The induced charges move directionally along the circuit and are output to a capacitor or electrometer in the form of current or an electrical signal, achieving effective output and utilization of the electrical signal. When the droplet detaches from the dielectric layer, the device switches to an open state, forming a current-disconnected circuit. Simultaneously, the charge transfer between the droplet and the PTFE film is accompanied by a chemical reaction, with electrons transferring from the water molecules in the droplet to the PTFE surface, causing the water molecules to generate H2O. + H2O + Rapid proton transfer to H3O + And ·OH. Simultaneously, electrons accumulated on the PTFE surface react with dissolved O2 to generate ·O2. - The PTFE then returns to its uncharged state. The droplet continues to rub against the membrane, and the cycle of charge transfer and chemical reaction described above repeats continuously.

[0034] Degradation performance study of E-TCE: To investigate the mechanism of action of E-TCE and the influence of multiple factors on CV catalytic degradation, a simple catalytic reaction device was constructed. The specific interface distribution is shown in the figure. Figure 3As shown in Figure a, the degradation rate under no-stimulation conditions is lower than that under stimulated conditions, indicating that external stimulation promotes the catalytic degradation process. Under no-stimulation conditions, the current in the circuit formed by the electrodes at both ends of the PTFE membrane originates from the triboelectric effect between the droplet and the membrane interface and the natural diffusion of ions in the solution. This current is characterized by weak intensity and disordered direction, making it difficult to drive a highly efficient catalytic reaction.

[0035] Figure 3 b illustrates the effect of different distances between the separatory funnel and the PTFE membrane on the CV degradation effect. As the height increases from 10 to 20 cm, the degradation rate increases from 50.6% to 92.3%. The increased impact velocity of the droplets upon reaching the membrane increases the contact area between the droplets and the membrane, increasing the interaction opportunities between CV molecules and active sites and species on the membrane surface. Therefore, the degradation efficiency gradually improves with increasing height. At a height of 20 cm, the contact area between the droplets and the membrane reaches an optimal state, and the active sites on the membrane surface fully participate in the reaction. However, when the height increases to 25 cm, the droplets splash due to excessive impact velocity, which reduces the effective contact area and ultimately lowers the degradation rate.

[0036] Figure 3 c. The effect of PTFE membrane tilt angle (30°, 45°, 60° and 75°) on CV degradation efficiency was investigated. When the tilt angle is small (30° and 45°), the component of gravity acting on the droplet along the inclined plane is small, while the surface tension has a relatively significant effect. This results in slow droplet flow and easy local accumulation, leading to uneven contact between CV molecules and membrane active sites, and a prolonged dissolved oxygen diffusion path. The diffusion flux of dissolved oxygen to the membrane surface active sites decreases with increasing path length, inhibiting the formation of active species and ultimately resulting in a slow degradation rate. When the tilt angle increases to 60°, the component of gravity and surface tension tend to be in dynamic equilibrium, allowing the liquid to flow uniformly and maximizing the contact area between CV and active sites. This accelerates dissolved oxygen mass transfer and improves the formation efficiency of active species, with the degradation rate reaching a maximum of 92.3% at 60 min. When the tilt angle is 75°, the component of gravity dominates the liquid flow. The excessively fast flow drastically reduces the contact time with the membrane, making it difficult for the CV molecule "adsorption-activation-degradation" cycle to complete. Furthermore, the charge distribution on the membrane surface becomes mismatched, causing the formation efficiency of active species to decline, and the final degradation efficiency is about 26% lower than at 60°.

[0037] To investigate the effect of dielectric layer thickness on CV degradation, this invention conducted experiments by varying the PTFE membrane thickness, and the results are as follows: Figure 3As shown in d, when the thickness of the PTFE medium layer increased from 0.05 mm to 0.1 mm, the CV degradation rate increased from 65.7% to 92.3%. At a thickness of 0.05 mm, due to poor charge storage and conduction stability, rapid dissipation easily occurred, and the weak solid-liquid interface interaction hindered the effective transfer of charge to dye molecules, resulting in limited degradation efficiency. When the thickness continued to increase to 0.3 mm, the degradation rate gradually decreased. When the thickness reached 0.5 mm, the degradation rate dropped to 49.7%. This is because an excessively thick medium layer would hinder the rapid transfer of friction-generated charges, causing uneven charge distribution, thereby weakening the catalytic degradation performance of the system.

[0038] Figure 3 e represents the effect of different capacitance values ​​on the CV degradation rate. When the capacitance is 10 nF and 22 nF, the CV degradation rate is relatively low. This is because low-capacitance capacitors have a limited charge storage threshold, failing to provide sufficient charge reserve for the E-TCE device, thus limiting the interface charge transfer efficiency and affecting ·OH and ·O2. - Insufficient generation of active substances makes it difficult to meet the requirements for efficient degradation of CV molecules, resulting in a low degradation rate. When the capacitance increases to 47 nF, the CV degradation rate reaches its optimal value of 92.3%. At this point, sufficient charge storage can drive efficient interfacial charge transfer, providing a stable driving force for the large-scale generation of active substances, enabling the conversion of ·OH and ·O2. - It can fully contact and react with CV molecules to maximize degradation efficiency. When the capacitance value is further increased to 68 nF, the CV degradation rate drops to 87.6%. This is because high capacitance values ​​tend to store excessive charge, leading to charge accumulation in the system. The accumulated charge increases migration resistance, reduces the effective utilization efficiency of charge, and thus inhibits the generation and action of active substances, ultimately causing the degradation rate to decrease instead of increase.

[0039] Figure 3The influence of the bulk effect on CV degradation efficiency was investigated. Results showed that in the electrodeless system, the CV degradation efficiency was at its lowest level of 71.3%. Due to the complete lack of directional charge injection channels and electric field driving conditions, it was almost impossible to generate active substances through triboelectric electrocatalysis within the system. Only a very small amount of active species could be generated through weak spontaneous reactions such as tribothermally induced thermal decomposition of CV molecules. Furthermore, the lack of an electrode to guide the efficient collision between active species and CV molecules resulted in insufficient degradation kinetics, ultimately leading to low degradation efficiency. The core of the bulk effect is to extend charge transport from the surface of the medium to the interior, achieving more efficient charge utilization. While the CV degradation rate improved somewhat in the single-electrode mode, it remained at a low level of 75.9%. This is because the single-electrode mode cannot achieve bulk effect regulation; charge transfer is confined to the surface of the medium layer, resulting in a significant charge transport bottleneck. Unidirectional charge injection easily leads to charge accumulation within the system, causing uneven distribution of active substances. Simultaneously, the single electrode can only construct a weak electric field, making it difficult to continuously provide kinetic drive for the reaction between active substances and CV molecules. These two factors limited the degradation efficiency. In contrast, the dual-electrode mode achieved optimal CV degradation performance based on the bulk effect, with a degradation rate as high as 92.3%. In this mode, the charge transport path extends from the surface of the dielectric layer to its interior, not only overcoming the surface charge transport bottleneck and avoiding charge accumulation, but also constructing a stable directional electric field. This electric field provides continuous power for the efficient collisions between active materials and CV molecules, ultimately ensuring the efficient degradation of CV. By adding excitation to the dual-electrode mode, the device regulates the current direction through rectification and energy storage mechanisms, stabilizing energy output and significantly enhancing the directionality and stability of the current. This regulated current can more efficiently activate active sites on the membrane surface, promoting the generation of active species and accelerating the catalytic degradation process of CV molecules.

[0040] Figure 3 The figure shows the effect of different initial concentrations of CV dyes on the degradation rate. The degradation efficiency of CV dyes exhibits a "first increase, then decrease" pattern with increasing initial concentration. When the CV concentration is 5 mg / L, the degradation rate of the E-TCE device is only 49.3%, which is relatively low. This is because at this concentration, the total number of CV molecules is relatively small, and the catalytic system has not yet reached the saturation threshold for producing active substances, resulting in a low probability of collision between CV molecules and active substances. A large amount of active substances fail to participate in the reaction, ultimately limiting the degradation efficiency. When the concentration is increased to 10 mg / L, the degradation rate reaches a peak of 92.3%. When the concentration continues to rise above 10 mg / L, the degradation rate gradually decreases, dropping to 64.0% at 20 mg / L. This is because the number of CV molecules far exceeds that of active substances, intensifying the competition between molecules for active substances. This leads to a large number of CV molecules remaining because they cannot react in time. At the same time, the remaining CV molecules undergo "accumulation and adsorption" on the surface of the PTFE medium layer, occupying both catalytic active sites and hindering charge transfer channels, doubly weakening the system's ability to produce active substances, ultimately reducing the catalytic efficiency.

[0041] Figure 3 h illustrates the effects of BQ and IPA on CV inhibition. The results show that after introducing BQ, the CV degradation rate decreased from 92.9% to 34.7%, indicating that ·O2- plays a major role in the catalytic degradation of CV. With the introduction of IPA, the degradation rate was 58.35%. This invention also simultaneously conducted CV quenching experiments with FFA; however, after adding FFA to the system, the CV degradation rate was 91.3%, which was not significantly different from the degradation rate without the scavenger. This phenomenon proves that 1O2 did not play an effective role in the CV degradation process of this system. The above results indicate that ·OH participates in the degradation process and promotes it, but its contribution to the reaction is weaker than that of ·O2-, while 1O2 has no significant contribution to the degradation process. This is consistent with… Figure 2 This aligns with the E-TCE degradation principle in c.

[0042] Figure 3 i) For the cycle performance test, the TCE membrane was subjected to five cycles of degradation experiment under the same conditions, and the membrane surface was cleaned with ethanol after each cycle. The test results showed that the catalytic efficiency remained above 88% after five cycles, which fully demonstrates that the PTEF membrane in the E-TCE device has good cycle stability.

[0043] To verify the universality of the E-TCE device in degrading pollutants, different pollutants (RhB, Mo, TC) were selected for degradation experiments. This invention demonstrated highly efficient degradation capabilities for various pollutants, with degradation rates all exceeding 80%, confirming its universality and providing a basis for its application in practical water treatment scenarios. The effect of droplet frequency on CV degradation was investigated. When the droplet frequency was 1 drop per second, the CV degradation rate was 78.5%; increasing it to 2 drops per second, the degradation rate reached 92.9%; further increasing it to 3 drops per second, the degradation rate decreased to 84.9%. This is because excessively slow droplet droplets lead to severe loss of interfacial charge and insufficient generation of active species, thus reducing the degradation rate; while excessively fast droplet droplets easily merge with old droplets that have not completely rolled off the membrane surface, not only shortening the contact reaction time between the interfacial charge and the pollutant but also reducing charge separation efficiency, ultimately causing a decrease in the degradation rate. A comparative experiment on the CV degradation performance of different polymer materials as triboelectric dielectrics showed that PTFE achieved a CV degradation rate of 92.9% under the E-TCE device, significantly higher than PI (84.2%), PET (79.8%), PP (76.5%), and PE (73.1%). This is because PTFE has the strongest electronegativity in the triboelectric sequence and possesses excellent hydrophobicity, enabling more efficient charge transfer at the solid-liquid interface, thereby improving the degradation rate.

[0044] Output Performance Study: To investigate the effects of different factors on the electrical signal output during the catalytic process, the influence of varying capacitance, height, concentration, film thickness, and contaminant concentration on the current output was studied under both excited and unexcited conditions. The results are as follows: Figure 4 As shown in the figure, the overall current output value under no-excitation conditions is smaller than that under excitation conditions. Figure 4 ).

[0045] Based on the principle of charge excitation, the current output of an E-TCE relies on an external capacitor to complete charge transfer, and the capacitance value directly affects the charge transfer efficiency. For example... Figure 4 As shown in Figure a, when the capacitor value is 15 nF, the current output is 4.5 nA; when the capacitance value increases to 22 nF, the current increases to 6 nA; and when the capacitance value further increases to 47 nF, the current reaches 8 nA. It can be seen that within the range of 15 nF to 47 nF, the current increases positively with the increase of the capacitor value, conforming to the formula I=C· (I is the current, C is the capacitance) (Rate of voltage change), when the experiment is stable The capacitance is basically constant. The larger the capacitance value, the stronger the capacitor's ability to store and transfer charge, and the higher the current. However, when the capacitance increases to 68 nF, the current decreases to 6 nA. This is because the capacitance value exceeds the adaptation threshold of TCE charge transfer. An excessively large capacitance value prolongs the capacitor's charging and discharging time, which is mismatched with the charge generation rate of E-TCE, resulting in a decrease in the actual charge transferred per unit time. Figure 4 b represents the effect of the CV falling from different heights on the current. It can be seen that at a distance of 20 cm, the current is 6 nA without excitation, and increases to 8 nA after excitation, which is 117% higher than without excitation. This is attributed to the injection of additional charge into the excitation circuit, significantly increasing the interfacial charge density and thus enhancing the electrical output. As the vertical distance between the PTFE membrane and the CV increases, the current first increases and then decreases. When the distance increases from 10 to 20 cm, the current increases from 3 nA to 8 nA. This is due to the increased kinetic energy of the CV, leading to improved effective contact area and charge efficiency with the membrane, resulting in a corresponding increase in current. However, when the height increases to 25 cm, the current decreases to 5 nA. This is because when the CV impacts the membrane surface, the droplets splash due to the impact force exceeding surface tension, reducing the effective contact area between the droplets and the membrane. Simultaneously, the violent impact disrupts the originally stable charge distribution on the membrane surface, increasing the interfacial charge transfer resistance, ultimately causing a decrease in the system current. Figure 4c represents the effect of the PTFE membrane tilt angle on the current output. When the tilt angle increases from 30° to 60°, the current increases from 3 nA to 8 nA. This is mainly because a larger tilt angle helps the droplets form a stable and continuous flow along the slope after impacting the membrane surface, thus prolonging the solid-liquid contact time and increasing the effective contact area. Simultaneously, the tilt angle guides the droplet flow direction to better align with the electrode layout, reducing charge loss during conduction and allowing the generated charge to be transferred to the electrodes more efficiently to form a current, ultimately driving the current to continuously increase with the tilt angle. However, when the tilt angle further increases to 75°, the current output decreases to 4 nA. This is because an excessively large tilt angle leads to an excessively fast droplet flow velocity, significantly shortening its spreading and contact time on the membrane surface, reducing the effective contact area, and ultimately lowering the interfacial charge density and current output. Figure 4 As can be seen, the film thickness has a significant regulatory effect on the current output. When the film thickness is 0.05 mm, the current is relatively low at 1.4 nA. This is because the 0.05 mm film is thin, resulting in poor charge storage and conduction stability and easy charge dissipation. As the thickness increases to 0.1 mm, the current reaches a maximum of 8 nA. However, as the thickness continues to increase to 0.3 mm and 0.5 mm, the current gradually decreases. When the thickness is 0.5 mm, the current drops to 3 nA. This is because an excessively thick film layer will hinder the rapid transfer of charges generated by friction, causing uneven charge distribution and increasing the resistance to charge migration, resulting in a decrease in current as the thickness increases. Figure 4 The effect of different CV concentrations on current output was investigated. The current reached a peak of 8 nA when the concentration was 10 mg / L. At lower concentrations (5 mg / L), the number of CV molecules was small, resulting in a low probability of collision with active sites and active species on the membrane surface, leading to insufficient charge generation motive force. When the concentration exceeded 10 mg / L, excessive CV molecules competed for active sites, hindering effective charge transfer, and causing the current to decrease with increasing concentration.

[0046] Figure 4 f represents the charge change trend over time. Within the reaction time of 0 to 60 min, the accumulated charge increased from 1 nC to 4.3 nC, indicating that the system's charge transfer capability continuously enhances as the reaction progresses. This trend demonstrates that charge effectively accumulates during continuous triboelectric electrocatalysis, reflecting the stable operation and efficient charge management capability of the E-TCE device. The lack of further charge accumulation from 0 to 60 min is because the system reached charge saturation. As degradation progresses, the charge generation rate at the PTFE membrane-droplet interface gradually stabilizes, and the energy storage module's capacitance approaches its upper limit. Therefore, charge accumulation reaches its maximum value around 50 min and remains stable.

[0047] The charge output characteristics of the TCE device and E-TCE under different factors were screened. The optimal reaction conditions obtained were completely consistent with the optimal parameters determined by CV degradation rate and current output characteristics. Moreover, the charge output was significantly enhanced under the excitation conditions.

[0048] Degradation mechanism: Figure 5 ESR spectra in a and 5b confirmed the presence of ·O2- and ·OH radicals. In the figures, almost no signal was observed at the initial reaction stage (0 min), indicating that almost no ·O2- and ·OH were generated without a bulk effect. After 3 min of reaction under unstimulated conditions, characteristic ESR signals became clearly visible, indicating that the system already possessed some radical generation capacity under unstimulated conditions, but the yield of active species was limited. Under stimulated conditions, the ESR signal intensity of ·O2- and ·OH was significantly enhanced. This is because the stimulation mechanism, by optimizing the system's charge storage capacity and directional transport efficiency, provided additional impetus for electron accumulation on the PTFE membrane surface, promoting dissolved oxygen reduction to ·O2-, and accelerated the oxidation reaction of water molecules at active sites, increasing the amount of ·OH generated. These results indicate that ·O2- and ·OH radicals are generated during the reaction, and that stimulated conditions promote the production of these active species, consistent with the above description of the promotion of catalytic degradation reactions under stimulated conditions.

[0049] Figure 5 c describes the working principle of TCE (Contact Electrocatalysis). In the initial stage, the CV dye comes into contact with the uncharged PTFE membrane. Due to electron transfer from water molecules, the PTFE membrane becomes negatively charged, while the membrane itself becomes positively charged. A water molecule loses an electron to become H₂O⁺, which can rapidly generate H₃O⁺ and ·OH through a proton transfer reaction. The generated ·OH, as a strong oxidizing species, participates in the catalytic degradation of the CV dye. When the PTFE membrane surface is negatively charged, surface electrons combine with O₂ in the droplet to generate ·O₂⁻, which also participates in the catalytic degradation of the CV. The uncharged PTFE can continue to contact with water, achieving electron transfer and thus creating a virtuous cycle.

[0050] Furthermore, when the CV solution interacts with the PTFE membrane through friction, e-generators are induced on the membrane surface. - With hole h + e - It can react with water molecules to produce OH. - And ·H, or combine with O2 to form ·O2 - ;and h + It continues to react with OH in the system - The reaction generates ·OH. When free radicals react with CV, these strong oxidizing free radicals attack the unsaturated groups and conjugated systems in CV, causing the large π-conjugated color system in the CV molecule to be gradually degraded and destroyed, turning it into a colorless compound, or even forming harmless products such as water and CO2.

[0051] Based on LC-MS analysis results ( Figure 6 The possible degradation pathways of CV in an E-TCE device were deduced. The degradation process begins with the removal of chloride ions from the fragmented cation (mz=372): hydroxyl radicals attack conjugated olefins, forming an external salt (mz=270) through dehydrogenation and hydrolysis, followed by hydrolysis into a ketone intermediate (m / z=269); simultaneously, hydroxyl radicals attack the benzene ring to form a complex (m / z285), which, due to the π-π conjugation between the π-benzene ring and the carbon group, combined with the electron-donating effect of the hydroxyl group on the electron cloud density of the benzene ring, is further cleaved into 4-dimethylaminocarboxaldehyde (m / z=149), and finally oxidized to a carboxylic acid (m / z=169); in addition, hydroxyl radicals can also directly attack the central carbon atom, causing CV to degrade into ketones (m / z=269) and 4-dimethylaminocarboxaldehyde (m / z=137), the latter of which, after demethylation and stepwise oxidation, is converted into aniline and para-aminobenzoic acid (m / z=137) and further decomposed into smaller molecular compounds.

[0052] The CV degradation pathway is a complete chain of “macromolecule fragmentation → functional group transformation (ketone, aldehyde, acid) → small molecule mineralization” linked by mass-to-charge ratio. There are three possible competing pathways: (1) N-demethylation; (2) chromophore ring structure breakage; (3) benzene ring cleavage and carboxylic acid oxidation.

[0053] Biotoxicity analysis: The developmental toxicity of CV and its degradation intermediates was assessed using the toxicity estimation software tool (TEST). Results are as follows: Figure 7 As shown, the vertical axis represents the developmental toxicity intensity, with higher values ​​indicating stronger toxicity. The assessment results show that the initial target pollutant C25H30N3Cl (CV) exhibited strong developmental toxicity, with a predicted value close to 1.0. After degradation treatment in the E-TCE device, the predicted toxicity value of the intermediate products in the solution showed a significant decreasing trend with the passage of reaction time, eventually maintaining a low level of around 0.4. This indicates that the structure of CV molecules was effectively destroyed during the catalytic degradation process in the E-TCE device, transforming into less toxic intermediate products, thus achieving a significant reduction in developmental toxicity.

[0054] The developmental toxicity of CV and its degradation intermediates, as well as their acute and chronic toxicity to fish, daphnia, and green algae, were assessed using TEST and ECOSAR models. The results are as follows: Figure 7 As shown. Figure 7 The vertical axis of 'a' represents the developmental toxicity intensity. The higher the value, the greater the toxicity. From CV to subsequent small molecule products, developmental toxicity decreases from 1.0 to about 0.4, showing an overall downward trend. Figure 7In diagram b, the dark blue CV at the bottom represents the initial pollutant, corresponding to higher values ​​and lower toxicity. CV1-CV11 are degradation intermediates, with some products (CV-3, CV-6, CV-10) appearing brick red, corresponding to lower values ​​and higher toxicity. Scatter plots of acute and chronic toxicity for fish, water fleas, and green algae more intuitively reflect the differences in toxicity. These two seemingly contradictory predictions indicate that although the conjugated structure of the original CV molecule has relatively low toxicity to aquatic organisms, its planar conjugated structure interferes with the normal development of the embryo, thus exhibiting strong developmental toxicity. While some small molecule intermediates produced during degradation have reduced developmental toxicity, they exhibit stronger toxicity to specific aquatic organisms. Therefore, a single toxicity assessment cannot comprehensively reflect the environmental risk of this degradation system; a comprehensive judgment based on multiple prediction results is necessary.

[0055] In summary, this invention designs a highly efficient TCE device based on solid-liquid triboelectric contact and further constructs a high-performance E-TCE device by coupling an excitation circuit. The excellent catalytic degradation performance and electro-output characteristics of this system for CV were systematically studied and confirmed, clarifying the key role of the excitation mechanism in improving system performance. Experimental results show that the E-TCE device significantly improves the electron transfer efficiency at the solid-liquid interface by optimizing charge storage and transport direction through the excitation circuit, and also provides a key driving force for the generation of active free radicals. ESR testing confirms that ·OH and ·O2... - It is the main active species for degradation, and the increased charge transport efficiency under stimulated conditions can promote the reduction of dissolved oxygen to O2. - This invention accelerates the oxidation of water molecules at active sites to generate ·OH, thereby enhancing the catalytic degradation effect. The E-TCE device achieves a CV degradation rate of 117% compared to the TCE device, with a peak electrical output current increased to 140% of the TCE device and a charge capacity increased by 268%, achieving a simultaneous and efficient improvement in catalytic performance and electrical output characteristics. Compared to traditional pollutant catalytic degradation technologies, the E-TCE device constructed in this invention requires no external energy source, achieving self-powered operation and significantly reducing energy consumption. Cyclic stability tests show that after five cycles of reuse, the system's CV degradation rate remains above 88%, demonstrating excellent reusability and stability. This green, self-powered catalytic technology shows significant application value and broad prospects in the fields of environmental remediation and sustainable energy utilization.

[0056] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for bulk-effect solid-liquid contact electrocatalytic removal of pollutants, characterized in that: Includes the following steps: (1) Constructing a triboelectric contact electrocatalytic component with a bulk effect structure: Using an insulating substrate (1) as a support, a bottom electrode (2) is set on the substrate, a dielectric layer (3) is fixed on the bottom electrode (2), and a top electrode (4) is set on the top of the dielectric layer (3); the bottom electrode (2) and the top electrode (4) are connected by conductive wires to form a closed loop, thereby obtaining a triboelectric contact electrocatalytic component; (2) Constructing a charge excitation and regulation module: A bridge rectifier circuit is built using diodes as the rectifier unit. The rectifier unit and the energy storage unit are connected in series and then connected to the closed loop to obtain a bulk effect solid-liquid contact electrocatalytic system. (3) Bulk effect solid-liquid catalysis: The droplets containing pollutants are driven by gravity to flow along the surface of the dielectric layer. Active species are generated by the interfacial charge transfer that occurs when the droplets come into contact with the dielectric layer. At the same time, the triboelectric signal generated by the triboelectric contact electrocatalytic component is rectified and stored by the charge excitation and regulation module to form a directional and stable current output. This current extends the charge transfer from the surface of the dielectric layer to the interior of the dielectric layer, further promoting the interfacial charge transfer and the generation of active species, thereby achieving the removal of pollutants in the water.

2. The method for removing pollutants by bulk effect solid-liquid contact electrocatalysis according to claim 1, characterized in that: The dielectric layer in step (1) is a polymer film, which is one of polytetrafluoroethylene, polyimide, polyethylene terephthalate, polypropylene or polyethylene.

3. The method for removing pollutants by bulk effect solid-liquid contact electrocatalysis according to claim 2, characterized in that: The dielectric layer in step (1) includes a polytetrafluoroethylene film.

4. The method for bulk effect solid-liquid contact electrocatalytic removal of pollutants according to any one of claims 1-3, characterized in that: The insulating substrate in step (1) is a PMMA organic glass plate, the bottom electrode is a double-sided copper tape, and the top electrode is a single-sided copper tape.

5. The method for bulk effect solid-liquid contact electrocatalytic removal of pollutants according to any one of claims 1-3, characterized in that: The energy storage unit mentioned in step (2) is a capacitor.

6. The method for bulk effect solid-liquid contact electrocatalytic removal of pollutants according to any one of claims 1-3, characterized in that: The bridge rectifier circuit described in step (2) is built using a breadboard, and the diodes include 1N4007.

7. The method for bulk effect solid-liquid contact electrocatalytic removal of pollutants according to any one of claims 1-3, characterized in that: The active species mentioned in step (3) include hydroxyl radicals and superoxide anion radicals.

8. The method for bulk effect solid-liquid contact electrocatalytic removal of pollutants according to any one of claims 1-3, characterized in that: The frictional contact between the droplet and the dielectric layer in step (3) controls the removal efficiency of pollutants by adjusting the droplet's falling height, the tilt angle of the dielectric layer, the thickness of the dielectric layer, the capacity of the energy storage unit, and / or the initial concentration of the pollutants.

9. The method for removing pollutants by bulk effect solid-liquid contact electrocatalysis according to claim 8, characterized in that: The droplet falls at a height of 10-25 cm, the dielectric layer tilts at an angle of 30°-75°, the dielectric layer is 0.05-0.5 mm thick, the energy storage unit has a capacity of 15-68 nF, and the initial concentration of the pollutant is 5-20 mg / L.

10. The method for removing pollutants by bulk effect solid-liquid contact electrocatalysis according to claim 1, characterized in that: The pollutants mentioned in step (3) are organic dyes in dyeing and printing wastewater, including crystal violet, rhodamine B, methylene blue or tetracycline.

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