A PDMS bionic chip system integrated by using a 3D sacrifice mold and an assembling method and application thereof

Abstract

The application discloses a kind of PDMS bionic chip system and its assembling method and application integrated forming by 3D sacrifice mould, and the system includes following functional components: integrated PDMS bionic chip, sewage total water inlet, online COD sensor, MCU controller, long-range spiral TENG power generation section, micro electromagnetic valve group, zoned parallel bionic alveolar reaction array, liquid metal composite catalytic microsphere, magnetic capture recovery cavity, treated water total outlet, pulse energy storage circuit, parallel inductive electrode pair;Through online COD sensor, water quality parameters are monitored in real time, closed-loop feedback mechanism of water quality, energy, reaction is constructed, zoned parallel bionic alveolar reaction array opening proportion and pulse driving intensity are dynamically regulated, charge polarization between pulse electric field and liquid metal is used, surface tension gradient is induced to form non-contact dynamic stirring, and efficient deep degradation of organic pollutants and lossless closed-loop recovery of catalytic material are realized.

Description

Technical Field

[0001] This invention relates to the field of microfluidic chip technology, and more particularly to a PDMS biomimetic chip system integrally formed using a 3D sacrificial mold, its assembly method, and its application. Background Technology

[0002] Microfluidic wastewater treatment technology, with its laminar mass transfer effect, short diffusion path, and high specific surface area at the micrometer scale, exhibits superior mass transfer efficiency and reaction kinetics compared to traditional reactors in the treatment of recalcitrant organic pollutants. However, existing microfluidic technologies face significant technical bottlenecks in engineering applications, particularly the extreme difficulty in fabricating multi-level, three-dimensional interconnected structures. Traditional microfluidic chips often employ single-layer planar channels or stacked two-dimensional bonded structures, fabricated through photolithography, wet etching, and thermoforming. This makes it difficult to construct non-intersecting, disconnected, multi-layered staggered structures, failing to realistically simulate the hierarchical, three-dimensional interconnected morphology of biological tissues such as alveoli and capillaries. Such three-dimensional channels require repeated alignment and bonding of multiple layers of PDMS, which at the micrometer scale are prone to interlayer misalignment, interfacial stress concentration, and sealing failure, leading to leakage and channel collapse. Furthermore, planar channels have a low specific surface area, limiting the processing capacity per unit volume and failing to meet the throughput requirements of engineering-scale water treatment.

[0003] The contradiction between microscale actuation and energy supply is equally prominent. The fluid in microchannels has a low Reynolds number and is mainly laminar. Traditional mechanical stirring and magnetic stirring have extremely low energy conversion efficiency at the micrometer scale, and the stirring components are prone to damaging the integrity of the chip packaging. Although ultrasonic actuation can enhance mass transfer, it has drawbacks such as high energy consumption, local overheating, and catalyst agglomeration and deactivation. Triboelectric nanogenerators (TENGs), as a water-powered self-driven technology, can convert fluid kinetic energy into electrical energy. However, in microfluidic systems, due to the low flow rate and small contact area, the output current is mostly in the nanoampere range, and the voltage fluctuates greatly, making it difficult to maintain a continuous and stable chemical reaction. At the same time, a continuous low-intensity electric field can easily induce water electrolysis, generating bubbles that block the flow channel and causing system operation interruption.

[0004] The challenges of catalyst immobilization and recovery remain unresolved. Nanocatalysts in microfluidic systems face a dual contradiction between immobilization and suspension: immobilized catalysts have their active sites coated, significantly increasing mass transfer resistance; suspended catalysts have good dispersibility and fully exposed active sites, but micron-level channels are prone to particle agglomeration and pipeline blockage, resulting in low outlet interception efficiency, high catalyst loss rate, and easy secondary pollution and raw material waste.

[0005] Gallium-based low-melting-point liquid metals possess high conductivity, room-temperature fluidity, and controllable surface oxide films, offering new pathways for electrode integration, catalytic enhancement, and material recovery in microfluidic systems. However, they cannot independently address bottlenecks such as insufficient energy supply, limited driving methods, and lack of intelligent control. While TENGs can achieve fluid energy harvesting, they suffer from weak output, difficulty in continuous driving, and susceptibility to electrolytic bubbles in microfluidic scenarios.

[0006] Therefore, existing microfluidic wastewater treatment technologies suffer from problems such as complex three-dimensional structure processing, high driving energy consumption, low energy utilization efficiency, prominent solid-liquid contradictions in catalysts, lack of intelligent system control, and difficulty in recycling catalytic materials. There is an urgent need to develop an integrated, self-driven, feedback-controlled, and recyclable biomimetic 3D micro-reaction system to break through traditional technical bottlenecks and achieve efficient, intelligent, and green wastewater treatment. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a PDMS biomimetic chip system integrated with a 3D sacrificial mold. This system integrates liquid metal interface control, TENG self-driven energy supply, pulsed electric field non-contact actuation, and online water quality feedback into a multi-field coupling mechanism. It overcomes TENG output limitations through pulsed energy storage and voltage boosting, and avoids bubble and electrolysis interference through a non-contact induced electric field. Utilizing the charge polarization effect between the pulsed electric field and the liquid metal, it induces a surface tension gradient to form non-contact dynamic stirring. Furthermore, it achieves efficient catalyst anchoring and non-destructive recovery through an oxide film interface switch, collaboratively addressing the technical deficiencies across the entire chain, including 3D processing, energy supply, catalytic mass transfer, and recycling.

[0008] Another object of the present invention is to provide an assembly method for the above-mentioned PDMS bionic chip system.

[0009] Another object of the present invention is to provide a method for treating wastewater using the above-mentioned PDMS bionic chip system.

[0010] To achieve the above objectives, the present invention is accomplished through the following technical solutions.

[0011] A PDMS biomimetic chip system integrally formed using a 3D sacrificial mold includes the following functional components: an integrated PDMS biomimetic chip, a wastewater inlet, an online COD sensor, an MCU controller, a long-range spiral TENG power generation section, a micro electromagnetic valve group, a partitioned parallel biomimetic alveolar reaction array, liquid metal composite catalytic microspheres, a magnetic capture and recovery chamber, a treated water outlet, a pulse energy storage circuit, and a parallel induction electrode pair. The integrated PDMS bionic chip is equipped with a main sewage inlet and an online COD sensor at its input end. The integrated PDMS bionic chip has a total treated water outlet at its output end. Wastewater first enters the pipeline through the wastewater inlet, then flows through the online COD sensor to complete the influent water quality detection, and then flows into the various functional components in the microchannel network of the integrated PDMS bionic chip for purification treatment, and finally flows out through the total treated water outlet. The integrated PDMS bionic chip is a one-piece cast structure, which integrates a preset microchannel network and functional chambers containing various functional components; the microchannel network extends from the main inlet pipe to branch pipes in stages, and the output ends of each branch pipe are connected to the main outlet pipe, forming a complete closed-loop flow channel structure with front-end branching and rear-end convergence. The main inlet pipe is equipped with a long-range spiral TENG power generation section; the branch pipes are equipped with micro electromagnetic valve groups on the pipe section before the branch pipes at the end of the bifurcation, each micro electromagnetic valve independently controls a parallel branch, each parallel branch is equipped with a partitioned parallel bionic alveolar reaction array along the fluid, and a magnetic capture and recovery chamber is provided downstream of the partitioned parallel bionic alveolar reaction array; the functional components in each functional chamber are connected sequentially through a microfluidic network, and there is no interlayer bonding interface; The inner wall of the long-range spiral TENG power generation section is composite with a PTFE friction layer, and the outer wall is wrapped with copper foil electrodes. The copper foil electrodes connect the long-range spiral TENG power generation section to the pulse energy storage circuit. The pulse energy storage circuit is also electrically connected to the parallel induction electrode pair, which is integrated in the PDMS wall on both sides of the partitioned parallel bionic alveolar reaction array. The partitioned parallel biomimetic alveolar reaction array includes alveolar microchambers arranged in a honeycomb three-dimensional pattern. Blind slots are symmetrically arranged on both sides of the alveolar microchambers. Liquid metal gel electrodes are provided inside the blind slots. The liquid metal gel electrodes are composed of gallium-based liquid metal and hydroxyl-terminated polydimethylsiloxane. An insulating wall is provided between the blind slots and the flow channels. The liquid metal composite catalytic microspheres are placed inside the alveolar microchambers; the liquid metal composite catalytic microspheres are gallium-based liquid metal microsphere composites with magnetic semiconductor composite catalyst particles anchored on their surface; The magnetic capture and recovery chamber is equipped with a non-uniform magnetic field and has independent injection and drainage ports. The online COD sensor is located upstream of the fluid in the long-range spiral TENG power generation section. The online COD sensor is electrically connected to the MCU controller via an external thin wire. The MCU controller is connected to the micro electromagnetic valve group via a drive wire and is used to control the opening ratio of the partitioned parallel bionic alveolar reaction array.

[0012] In the above technical solution, the integrated PDMS bionic chip has a length of 20~200mm, a width of 10~150mm, and a thickness of 5~30mm.

[0013] In the above technical solution, the integrated PDMS bionic chip is made of a polymer material with dielectric insulating properties, preferably PDMS or PDMS derivatives.

[0014] In the above technical solution, the stepwise branching refers to the upstream pipe segment branching into at least two downstream pipe segments, and the downstream pipe segments can continue to branch into the next lower level of pipe segments, with the diameter of the branch pipes decreasing stepwise; the diameter of the main inlet pipe is 200~2000μm, the diameter of the branch pipes is 150~1500μm, and the total number of branch pipes is 10~1000.

[0015] In the above technical solution, the partitioned parallel biomimetic alveolar reaction array adopts a three-dimensional bifurcated flow channel.

[0016] In the above technical solution, the number of alveolar microchambers is 10 to 1000, the volume of a single alveolar microchamber is 0.1 to 100 μL, and the inner diameter is 100 to 2000 μm.

[0017] In the above technical solution, the thickness of the PTFE friction layer is 10~100μm.

[0018] In the above technical solution, the width of the blind groove is 100~300μm.

[0019] In the above technical solution, the thickness of the insulating wall between the blind groove and the flow channel is 0.01~0.5mm.

[0020] In the above technical solution, the content of gallium-based liquid metal in the liquid metal gel electrode is 50wt%~95wt%.

[0021] In the above technical solution, the mass ratio of gallium-based liquid metal microspheres to magnetic semiconductor composite catalyst particles in the liquid metal composite catalytic microspheres is (5~20):1, and the magnetic semiconductor composite catalyst particles are uniformly embedded on the surface of the liquid metal microspheres.

[0022] In the above technical solution, the gallium-based liquid metal is selected from one or more of EGaIn, Galinstan and their modified alloys; the magnetic semiconductor composite catalyst is selected from magnetic core-shell structure materials or semiconductor composite materials, and the magnetic core-shell structure material is preferably an iron-based oxide supported on carbon-based, metal oxide or sulfide semiconductors.

[0023] In the above technical solution, the online COD sensor includes a carbon-based working electrode, a noble metal counter electrode, and a silver-based reference electrode.

[0024] In the above technical solution, the online COD sensor is located upstream of the fluid in the long-range spiral TENG power generation section. Specifically, it can be installed at the front end of the main sewage inlet, or between the main sewage inlet and the integrated PDMS bionic chip, or on the main inlet pipe upstream of the long-range spiral TENG power generation section. Depending on the location of the online COD sensor, it can be installed externally or directly embedded in the inner wall or side wall of the main inlet pipe inside the chip to achieve real-time detection of the inlet water quality.

[0025] In the above technical solution, the pulse energy storage circuit includes a rectifier bridge and an energy storage capacitor. The rectifier bridge includes an MBR10100 Schottky voltage multiplier rectifier bridge. The energy storage capacitor is a 100nF high-voltage ceramic energy storage capacitor.

[0026] In the above technical solution, the magnetic capture and recovery chamber has two arrangement forms: Arrangement form one is that a magnetic capture and recovery chamber is set downstream of each of the partitioned parallel bionic alveolar reaction arrays; Arrangement form two is that the outflows of all partitioned parallel bionic alveolar reaction arrays are merged and connected to the same magnetic capture and recovery chamber.

[0027] The assembly method of the above-mentioned PDMS bionic chip system includes the following steps: S1. A water-soluble polyvinyl alcohol (PVA) sacrificial mold was prepared by stereolithography (SLA) 3D printing. The cavity of the mold defines the microchannel network and functional chambers of each functional component in the integrated PDMS bionic chip. The surface roughness of the channel is controlled at Ra < 0.8 μm. S2, polydimethylsiloxane (PDMS) is mixed with a curing agent and injected into the water-soluble polyvinyl alcohol sacrificial mold obtained in S1. The mixture is then degassed, cured, and hydrolyzed under vacuum to obtain an integrated PDMS bionic chip. S3, liquid metal gel is slowly injected into the blind grooves on both sides of the alveolar microchamber at a flow rate of 0.1~1.0μL / min to obtain a reaction chip with integrated liquid metal gel electrodes; S4, complete the assembly of the sensor and circuit module; S5. Under conditions of 20~50℃ and ultrasonic power of 100~500W, gallium-based liquid metal microspheres with magnetic semiconductor composite catalyst particles anchored on their surface are ultrasonically treated in a weakly acidic solution with pH=5.0~7.0. Acoustic cavitation breaks the gallium-based liquid metal into microspheres with uniform particle size. A Ga2O3 oxide film of a set thickness range is generated in situ on the surface of the microspheres. The magnetic semiconductor composite catalyst particles are anchored to the surface of the microspheres through physical embedding and chemical bonding. After ultrasonic preparation, the microspheres are washed with deionized water to remove free particles, and liquid metal composite catalyst microspheres are obtained. The liquid metal composite catalyst microspheres are placed inside the alveolar microchambers to complete the overall system assembly.

[0028] In S2, the mass ratio of polydimethylsiloxane to curing agent is (8~15):1.

[0029] In S2, the degassing time is 15-30 minutes.

[0030] In S2, the curing temperature is ≤40℃ and the curing time is 6~12 hours.

[0031] In S2, the hydrolysis operation is as follows: circulating and rinsing in a constant temperature deionized water bath at 60~95℃ for 8~24 hours.

[0032] In step S3, the liquid metal gel is obtained by stirring gallium-based liquid metal and hydroxyl-terminated polydimethylsiloxane for 10-30 minutes.

[0033] In S5, the weakly acidic solution includes an aqueous solution of acetic acid.

[0034] In step S5, the number of washing cycles is 3 to 5.

[0035] The above-mentioned PDMS bionic chip system for treating wastewater includes the following steps: Step 1: Start the influent micro-pump and set the flow rate to 0.5~5.0 mL / min. The MCU controller adjusts the opening ratio and pulse drive parameters of the zonal parallel bionic alveolar reaction array according to the concentration of the wastewater to be treated. The activation ratio and pulse drive parameters corresponding to the concentration of the wastewater to be treated are set as follows: When the influent COD concentration is ≥180mg / L, it is judged as a high pollution load. The activation ratio of the partitioned parallel bionic alveolar reaction array is 100%, the frequency is 100Hz, the pulse release threshold voltage is set to 100V, and the pulse width is 5ms. When the influent COD concentration is less than 180 mg / L, it is judged as a medium pollution load. The activation ratio of the zonal parallel bionic alveolar reaction array is 50%, the frequency is 50 Hz, the pulse release threshold voltage is set to 50 V, and the pulse width is 10 ms. When the influent COD concentration is ≤50mg / L, it is judged as a low pollution load. The activation ratio of the partitioned parallel bionic alveolar reaction array is 20%, the frequency is 20Hz, the pulse release threshold voltage is set to 20V, and the pulse width is 15ms.

[0036] Step 2: When the enriched volume of microspheres in the magnetic capture and recovery chamber reaches 60%~90% of the effective volume of the magnetic capture and recovery chamber, stop water intake and inject a complexing agent buffer solution through the injection port for static soaking; citric acid selectively dissolves the Ga2O3 oxide film on the surface of the microspheres, separating the magnetic semiconductor composite catalyst particles from the liquid metal matrix; graded recovery is achieved by utilizing density and magnetic differences, with the liquid metal microspheres settling at the bottom for collection and the magnetic semiconductor composite catalyst particles floating on the upper layer for magnetic collection; both materials are recycled after washing, drying or calcination activation; Step 3: Discharge the residual waste liquid in the magnetic capture and recovery chamber from the drain port, rinse the chamber with deionized water and restart the water inlet. The system resumes continuous operation, realizing the full-process recycling of the flow channel structure, liquid metal and magnetic semiconductor composite catalyst.

[0037] In step 2, the complexing agent buffer solution includes citrate buffer solution, the concentration of the complexing agent in the complexing agent buffer solution is 0.01~1.0 mol / L, and the pH value is 3.0~6.0.

[0038] In step 2, the static soaking time is 10-30 minutes.

[0039] In step 2, the recovered magnetic semiconductor composite catalyst is washed with deionized water and activated at 350~450℃ for 1~4h, then dried and recycled.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The PDMS bionic chip system of the present invention uses water-soluble PVA sacrificial mold to realize the integrated molding of the flow channel, without the need for multi-layer bonding and alignment packaging, which solves the problems of complex three-dimensional microfluidic processing, sealing failure, leakage and cracking, and has the advantages of stable structure, simple processing, low cost and long service life.

[0041] (2) The PDMS bionic chip system of the present invention adopts a non-contact liquid metal gel electrode, which is completely isolated from sewage. In principle, it avoids electrolysis, bubble blockage and electrode corrosion. The system is safer and more stable in operation, and its reliability is significantly better than that of traditional immersion electrode microreactors.

[0042] (3) The PDMS bionic chip system of the present invention adopts the TENG power generation-rectification energy storage-pulse drive mode to realize the system self-powered logic control supplemented by energy capture. It does not require an external power supply to drive the bionic system, which solves the bottleneck of weak output of traditional triboelectric generators and inability to drive micro-reactions. It has higher energy utilization and wider application scenarios.

[0043] (4) The PDMS biomimetic chip system of the present invention uses an oxide film to anchor the catalyst and induces Marangoni flow through a pulsed electric field to enhance mass transfer, which not only ensures high catalytic activity, but also solves the solid-liquid contradiction of the catalyst. It can deeply degrade pollutants under light-free conditions, and the treatment efficiency is much higher than that of traditional microreactors.

[0044] (5) The PDMS bionic chip system of the present invention can intelligently adjust the reaction unit and driving parameters according to the COD concentration of the influent, realize on-demand treatment and energy-saving operation, have strong resistance to water quality fluctuations, and the system operation is more economical and efficient.

[0045] (6) The PDMS bionic chip system of the present invention uses citric acid to gently peel off liquid metal and catalyst, and achieves non-destructive closed-loop recycling. It has low corrosion rate, high number of cycles, no secondary pollution, high overall integration, small size, mature process, and stronger engineering practicality and promotion value.

[0046] (7) This invention achieves a deep synergy of energy capture, field-effect mass transfer and efficient catalysis. By converting fluid mechanical energy into electrical energy through a long-range spiral TENG, and by using a pulsed electric field to couple liquid metal microspheres to induce Marangoni spin, the technical bottleneck of low Reynolds number and limited mass transfer in microfluidic systems is overcome without introducing an external power source and mechanical stirring equipment, thus achieving efficient pollutant degradation under self-driven conditions. Attached Figure Description

[0047] Figure 1 This is an overall structural diagram of the PDMS bionic chip system of Embodiment 1 of the present invention; Figure 2 This is a flowchart of the electrochemical sensor and MCU feedback control logic of the present invention; Figure 3 This is a diagram of the alveolar-electrode insulation structure of the present invention; Figure 4 Simulated diagram of the forces and spin streamlines of liquid metal composite catalytic microspheres under a pulsed electric field; Figure 5 This is the dissolution kinetics curve of the liquid metal oxide film in citric acid solution.

[0048] Among them, 1: integrated PDMS bionic chip, 2: sewage inlet, 3: online COD sensor, 4: MCU controller, 5: long-range spiral TENG power generation section, 6: micro electromagnetic valve group, 7: partitioned parallel bionic alveolar reaction array, 8: liquid metal composite catalytic microspheres, 9: magnetic capture and recovery chamber, 10: treated water outlet, 11: pulse energy storage circuit, 12: parallel induction electrode pair. Detailed Implementation

[0049] The following examples are intended to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0050] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained commercially or prepared according to conventional methods known to those skilled in the art.

[0051] Example 1 A PDMS biomimetic chip system integrally formed using 3D sacrificial molds, such as Figure 1 As shown, it includes the following functional components: 1. Integrated PDMS bionic chip; 2. Wastewater inlet; 3. Online COD sensor; 4. MCU controller; 5. Long-range spiral TENG power generation section; 6. Micro electromagnetic valve group; 7. Partitioned parallel bionic alveolar reaction array; 8. Liquid metal composite catalytic microspheres; 9. Magnetic capture and recovery chamber; 10. Treated water outlet; 11. Pulse energy storage circuit; 12. Parallel induction electrode pair. The integrated PDMS bionic chip 1 has a wastewater inlet 2 and an online COD sensor 3 at its input end; the wastewater inlet 2 is located upstream of the online COD sensor 3; the integrated PDMS bionic chip 1 has a treated water outlet 10 at its output end. Wastewater first enters the pipeline through the wastewater inlet 2, then flows through the online COD sensor 3 to complete the influent water quality detection, and then flows into the various functional components in the microchannel network of the integrated PDMS bionic chip 1 for purification treatment, and finally flows out through the treated water outlet 10. The integrated PDMS bionic chip 1 is a one-piece cast structure with a length × width × thickness of 100mm × 50mm × 10mm, and is made of polydimethylsiloxane (PDMS). It integrates a preset microfluidic network and functional chambers containing various functional components. The microfluidic network extends from the main inlet pipe with a diameter of 800μm in two stages to branch pipes. The main inlet pipe, as the 0th stage pipe segment, branches into 3 downstream pipe segments. The 3 downstream pipe segments continue to branch into the next stage pipe segments (i.e., the terminal branch pipes). The diameter of the branch pipes decreases step by step. The output ends of all terminal branch pipes (a total of 24) are connected to the main outlet pipe, forming a complete closed-loop flow channel structure with front-end branching and rear-end convergence. The fluid in the main inlet pipe enters the branch pipe after passing through the long-range spiral TENG power generation section 5 installed on the main inlet pipe. The branch pipe is equipped with a micro electromagnetic valve group 6 (located outside the chip) on the pipe section before the branch pipe at the end of the bifurcation. The micro electromagnetic valve group 6 includes 3 micro electromagnetic valves, each of which independently controls a parallel branch. Each parallel branch is equipped with a partitioned parallel bionic alveolar reaction array 7 along the fluid. The opening ratios of the micro electromagnetic valve group 6 for the three branches are 20% (corresponding to 64 alveolar microchambers), 30% (corresponding to 96 alveolar microchambers), and 50% (corresponding to 160 alveolar microchambers), respectively. A magnetic capture and recovery chamber 9 is set downstream of the partitioned parallel bionic alveolar reaction array 7. After the outflow of all partitioned parallel bionic alveolar reaction arrays 7 merges, they are connected to the same magnetic capture and recovery chamber 9. The functional components in each functional chamber are connected sequentially through a microfluidic network without interlayer bonding interfaces. The inner wall of the long-range spiral TENG power generation section 5 is composited with a 50μm thick PTFE friction layer, and the outer wall is wound with copper foil electrodes. The copper foil electrodes connect the long-range spiral TENG power generation section 5 to the pulse energy storage circuit 11. The pulse energy storage circuit 11 includes an MBR10100 Schottky voltage multiplier rectifier bridge and a 100nF high-voltage ceramic energy storage capacitor. The pulse energy storage circuit 11 is also electrically connected to the parallel induction electrode pair 12, which is integrated into the PDMS wall on both sides of the partitioned parallel bionic alveolar reaction array 7. The parallel biomimetic alveolar reaction array 7 comprises 320 alveolar microchambers arranged in a honeycomb pattern (each chamber has a volume of 0.5 μL and an inner diameter of 1000 μm). Symmetrical blind grooves with a width of 150 μm are arranged on both sides of each alveolar microchamber. Liquid metal gel electrodes are installed inside the blind grooves. These electrodes are composed of EGaIn liquid metal and hydroxyl-terminated polydimethylsiloxane, with EGaIn liquid metal comprising 75 wt% of the electrode. A 0.1 mm thick insulating wall is provided between the blind grooves and the flow channels. Liquid metal composite catalytic microspheres 8 are placed inside the alveolar microchambers; liquid metal composite catalytic microspheres 8 are a composite of Fe3O4@g-C3N4 composite catalyst particles and EGaIn liquid metal microspheres, magnetic semiconductor composite catalyst particles are uniformly embedded on the surface of liquid metal microspheres and are in direct contact with wastewater, and the interior of liquid metal microspheres is a pure liquid metal matrix.

[0052] The magnetic capture and recovery chamber 9 is equipped with a non-uniform magnetic field and has independent injection and drainage ports. The online COD sensor is located upstream of the fluid in the long-range spiral TENG power generation section, specifically externally and independently installed between the main sewage inlet 2 and the integrated PDMS bionic chip 1. The online COD sensor 3 includes a carbon-based working electrode, a noble metal counter electrode, and a silver-based reference electrode. The online COD sensor 3 is electrically connected to the MCU controller 4 via an external thin wire. The MCU controller 4 is connected to the micro solenoid valve group 6 via a drive wire to control the opening ratio of the partitioned parallel bionic alveolar reaction array 7.

[0053] Example 2 The assembly method of the above-mentioned PDMS bionic chip system includes the following steps: S1. Preparation of water-soluble polyvinyl alcohol (PVA) sacrificial mold by stereolithography (SLA): Using an SLA stereolithography 3D printer with an accuracy of ±5μm, water-soluble PVA with a molecular weight of 30,000 was used as raw material to print an integrated sacrificial mold according to the three-dimensional model. The cavity of the mold defines the microchannel network and functional chambers of each functional component in the integrated PDMS bionic chip 1 (multi-level bifurcated alveolar microchambers and electrode blind groove structure), and the surface roughness of the flow channels is controlled at Ra < 0.8μm. The prepared sacrificial mold is placed in a silanized polytetrafluoroethylene mold box.

[0054] S2, Polydimethylsiloxane (PDMS) Integrated Injection and Sacrificial Mold Dissolution: Mix PDMS prepolymer and platinum-catalyst-containing siloxane crosslinking curing agent at a mass ratio of 10:1, vacuum degas for 20 minutes, and slowly inject into the surface of the sacrificial mold to completely cover all structures; place the whole in a 35°C constant temperature oven for 8 hours to cure, and the temperature must be strictly controlled below 40°C to prevent early heat deformation of the PVA mold. After the PDMS is completely crosslinked and cured, transfer it to an 85°C constant temperature deionized water bath for 12 hours to circulate and rinse, so that the internal PVA sacrificial mold is completely dissolved, and an integrated PDMS bionic chip 1 with a through 3D flow channel and an independent electrode blind groove is obtained. The inside of the flow channel is dried with nitrogen.

[0055] S3, Micro-injection Integration of Liquid Metal Gel Electrodes: 75 wt% EGaIn and 25 wt% hydroxyl-terminated polydimethylsiloxane were stirred in a vacuum mixer for 20 minutes to obtain a liquid metal gel. This liquid metal gel was then slowly injected into the blind grooves on both sides of the alveolar microchambers at a flow rate of 0.2 μL / min through a pre-reserved injection port on the chip (micro-injection pump). Utilizing the capillary constraint of the blind grooves and the shear-thinning properties of the gel, bubble-free and leak-free filling was achieved. After static stabilization, the high viscosity of the gel allowed the electrodes to remain stably anchored within the 150 μm wide blind grooves, preventing displacement due to gravity and ensuring a constant electrode spacing of 0.1 mm. This yielded a reaction chip with integrated liquid metal gel electrodes.

[0056] S4, Sensor and circuit module assembly: Combine carbon-based working electrode, noble metal counter electrode and silver-based reference electrode to complete the assembly of online COD sensor 3; connect online COD sensor 3, MCU controller 4, micro solenoid valve group 6, pulse energy storage circuit 11 and parallel sensing electrode pair 12 accordingly.

[0057] S5, Preparation and Assembly of Liquid Metal Composite Catalytic Microspheres: 10g of EGaIn liquid metal and 1g of Fe3O4@g-C3N4 composite catalyst (molar ratio 1:1) were ultrasonically treated for 30min in an aqueous acetic acid solution (concentration 0.005mol / L, pH=5.5±0.1) under constant temperature water bath at 30℃ and power at 300W; ultrasonic cavitation broke the gallium-based liquid metal into uniform microspheres of 60μm; in an oxygen-containing environment, Ga2O3 was instantaneously generated in situ on the surface of the microspheres. An oxide film is formed by physically embedding and chemically bonding magnetic semiconductor composite catalyst particles onto the surface of microspheres, creating a "liquid metal marble" structure with high mechanical strength. Since the coordination ability of acetate ions is insufficient to overcome the lattice energy of the oxide film, the Ga2O3 oxide film stably grows to 3-5 nm. After preparation, the microfiltration washing with deionized water is performed three times to remove free particles, resulting in stable liquid metal composite catalytic microspheres 8. The liquid metal composite catalytic microspheres 8 are then placed inside the alveolar microchambers to complete the overall system assembly.

[0058] Example 3 With reference to the accompanying drawings, the working principle of the above-mentioned PDMS bionic chip system and the cooperation relationship of its components are explained as follows.

[0059] (a) such as Figure 2 The diagram shows the online COD sensor and MCU feedback control logic flow. The influent micro pump is started to pump the sewage into the pipeline from the sewage inlet 2, and then flows through the online COD sensor 3 to complete the influent water quality detection. The online COD sensor 3 collects the electrochemical signal of the sewage in real time. Then the MCU controller 4 converts the electrochemical signal into the corresponding chemical oxygen demand (COD) value, and performs algorithm analysis and COD concentration level determination. The MCU controller 4 matches the opening ratio of the corresponding micro solenoid valve group 6 and the pulse drive parameters of the pulse energy storage circuit 11 according to the determination result. The activation ratio and pulse drive parameters corresponding to the concentration of the wastewater to be treated are set as follows: When the influent COD concentration is ≥180mg / L, it is judged as a high pollution load. The activation ratio of the partitioned parallel bionic alveolar reaction array is 100%, the frequency is 100Hz, the pulse release threshold voltage is set to 100V, and the pulse width is 5ms. When the influent COD concentration is less than 180 mg / L, it is judged as a medium pollution load. The activation ratio of the zonal parallel bionic alveolar reaction array is 50%, the frequency is 50 Hz, the pulse release threshold voltage is set to 50 V, and the pulse width is 10 ms. When the influent COD concentration is ≤50mg / L, it is judged as a low pollution load. The activation ratio of the partitioned parallel bionic alveolar reaction array is 20%, the frequency is 20Hz, the pulse release threshold voltage is set to 20V, and the pulse width is 15ms.

[0060] (II) Pulsed electric field-induced catalytic degradation and the stress and spin streamline structure of liquid metal composite catalytic microspheres under pulsed electric field Wastewater flows through the long-range spiral TENG power generation section 5, where it undergoes liquid-solid friction electrification with the inner PTFE friction layer, and the copper foil electrodes on the outer wall induce alternating charges. The alternating charges are converted into direct current by the MBR10100 Schottky voltage multiplier rectifier bridge and stored in the high-voltage ceramic capacitor. When the voltage across the capacitor accumulates to the set value (i.e., the pulse drive parameters matched by the MCU controller 4), the MCU controller 4 controls the thyristor inside the pulse energy storage circuit 11 to conduct, instantly releasing the high-voltage pulse to the parallel induction electrode pair 12. like Figure 3 and Figure 4 As shown, the metal gel electrode and the reaction liquid inside the alveolar microchamber are physically isolated (electrically insulated) by a 0.1 mm PDMS insulating wall. No macroscopic current flows through the wastewater during system operation. The degradation reaction is entirely based on the heterogeneous catalytic mechanism of the microsphere surface, avoiding electrolytic side reactions and electrode corrosion, thus ensuring the safety and stability of the electrocatalytic process. A high-voltage pulsed electric field is applied to the liquid metal composite catalytic microsphere 8 inside the alveolar microchamber through the liquid metal gel electrode. The uneven charge distribution on the surface of the liquid metal composite catalytic microsphere 8 induces a surface tension difference, triggering Marangoni convection streamlines and driving the liquid metal composite catalytic microsphere 8 to form a high-frequency spin. The spin process creates local turbulence at the micrometer scale, significantly enhancing mass transfer efficiency and improving catalytic degradation performance. Simultaneously, the liquid metal acts as an electron shuttle to activate the added potassium peroxymonosulfate PMS, generating sulfate radicals and hydroxyl radicals (·OH), which deeply mineralize and decompose recalcitrant organic pollutants in the wastewater under light-free conditions.

[0061] Figure 4 The solid horizontal line in the middle is the central axis of symmetry of the micro-reaction channel and the liquid metal composite catalytic microsphere, used to help illustrate the spatial symmetrical distribution relationship between the high-voltage pulsed electric field lines and the Marangoni convection streamlines.

[0062] (III) Magnetic interception and solid-liquid separation: After degradation, the water flows to the magnetic capture and recovery chamber 9. The liquid metal composite catalytic microspheres 8 after reaction are completely adsorbed and intercepted on the chamber wall under the action of non-uniform magnetic field. After treatment, the water flows out smoothly and is collected, thus realizing solid-liquid separation.

[0063] like Figure 5 As shown, a dissolution kinetic curve of a liquid metal oxide film (Ga2O3 oxide film) in citric acid solution was constructed. The horizontal axis represents the immersion time (min), and the vertical axis represents the oxide film dissolution rate (%). Curve A represents the dissolution process of the Ga2O3 oxide film in a citric acid buffer solution at pH 4.5. Under this pH condition, the oxide layer on the liquid metal surface is in the chemically stable region, with a dissolution rate of <0.01 nm / min. The dissolution rate can reach over 98.5% within a set time (15 min). Curve B represents the dissolution in pure water at pH 7.0, with a substrate metal corrosion rate of <0.15%. This curve intuitively demonstrates the selective dissolution characteristics of citric acid on the oxide film on the liquid metal surface, enabling efficient separation and recovery of magnetic semiconductor composite catalyst particles from the liquid metal substrate, with minimal impact on the corrosion of the substrate material.

[0064] Example 4 The method for treating sulfonamide organic wastewater with an initial concentration of 200 mg / L using the above-mentioned PDMS biomimetic chip system includes the following steps: Step 1: Start the influent micro-pump, setting its flow rate to 1.0 mL / min to ensure sufficient hydraulic retention time for catalytic degradation of the wastewater within the partitioned parallel biomimetic alveolar reaction array. Wastewater (sulfamethoxazole aqueous solution) enters the pipeline through the main wastewater inlet 2, then flows through the online COD sensor 3 for influent water quality detection. If the influent COD concentration is detected to be >180 mg / L, it is determined to be a high pollution load. The MCU controller 4 controls the micro-solenoid valve group 6 to open all 320 alveolar microchambers, and the partitioned parallel biomimetic alveolar reaction array 7 is opened at 100%. Simultaneously, the pulse drive frequency is set to 100 Hz. The energy storage capacitor accumulates to 100 V and then discharges instantaneously with a pulse width of 5 ms. The induced electric field penetrates the PDMS wall and acts within the alveoli. Intense Marangoni spins (approximately 85 Hz) are observed in the composite microspheres, creating localized turbulence within the nanoliter space. 15 mmol / L of PMS is simultaneously added via the micro-pump. Under high-frequency stirring of liquid metal composite catalytic microspheres 8, PMS is converted into sulfate radicals (SO4). The reaction produced hydroxyl radicals (·OH) and hydroxyl radicals; after 180 s, the degradation rate of SMX reached 97.4%.

[0065] Step 2: After the reaction is complete, the liquid metal composite catalyst microspheres 8 are intercepted using a 0.5T non-uniform magnetic field. A 0.1 mol / L citrate buffer solution (prepared from deionized water and citric acid) with pH=4.5 is injected through the injection port and statically soaked for 15 min. The citric acid selectively dissolves the Ga2O3 oxide film on the surface of the microspheres, separating the magnetic semiconductor composite catalyst particles from the liquid metal matrix. The oxide film dissolution rate is >98%. The fractional recovery is achieved by utilizing density and magnetic differences. The magnetic semiconductor composite catalyst particles float on the upper layer and are collected by magnetic force, while the liquid metal microspheres settle at the bottom and are collected. The recovery rate is verified to be 98% by weighing, and the loss of the liquid metal matrix is ​​extremely low.

[0066] Example 5 The method for treating Rhodamine B dye wastewater with an initial concentration of 50 mg / L using the above-mentioned PDMS biomimetic chip system includes the following steps: Step 1: Start the influent micro-pump, setting its flow rate to 1.0 mL / min to ensure sufficient hydraulic retention time for catalytic degradation of the wastewater within the partitioned parallel biomimetic alveolar reaction array. Wastewater enters the pipeline through the main wastewater inlet 2 and then flows through the online COD sensor 3 for influent water quality detection. A COD concentration of 50 mg / L is detected, classifying it as a low pollution load. The MCU control module controls the micro-solenoid valves to open 64 alveolar microchambers, while the remaining 256 alveolar microchambers remain closed. The partitioned parallel biomimetic alveolar reaction array 7 is activated at 20% capacity, and the pulse drive frequency is set to 20 Hz. The energy storage capacitor discharges instantaneously after accumulating 20V, with a pulse width of 15 ms. The induced electric field penetrates the PDMS wall and acts within the alveoli. Intense Marangoni spins (approximately 18 Hz) are observed in the composite microspheres, creating localized turbulence within the nanoliter space. 15 mmol / L of PMS is simultaneously added via the micro-pump. Under low-frequency stirring of liquid metal composite catalytic microspheres 8, PMS is rapidly converted into sulfate radicals (SO42-). The reaction involves the reaction of hydroxyl radicals (·OH) with the dye molecules (such as Rhodamine B) and hydroxyl radicals (·OH). After 120 seconds of reaction, the degradation rate of dye molecules (such as Rhodamine B) reaches 99.2%.

[0067] In low-load mode, the system energy consumption is reduced by approximately 72% compared to high-load mode (100% activation rate). Because the liquid metal microspheres still maintain their basic inductive spin, the effluent decolorization rate remains above 99% at a low flow rate (1.0 mL / min), achieving optimal energy efficiency.

[0068] Step 2: After the reaction is complete, liquid metal composite catalytic microspheres 8 are intercepted using a 0.5T non-uniform magnetic field. A 0.1 mol / L citrate buffer solution (pH 4.5) is injected through the injection port, and the microspheres are statically soaked for 15 minutes. The citrate ions react with Ga... 3+It has strong coordination ability, which can promote the coordination dissolution of the Ga2O3 oxide film on the surface, so that the magnetic semiconductor composite catalyst particles are separated from the liquid metal matrix, and the oxide film dissolution rate is >98%. The fractional recovery is achieved by utilizing density difference and magnetic difference. The magnetic semiconductor composite catalyst particles float on the upper layer and are collected by magnetic force, while the liquid metal microspheres settle at the bottom and are collected. The recovery rate is verified to be 98.5% by weighing method, and the loss of liquid metal matrix is ​​extremely low.

[0069] Example 6 The regeneration process described below was repeated 10 times for the treatment of sulfamethoxazole aqueous solution with an initial concentration of 200 mg / L in Example 4. The regeneration process was as follows: the magnetic semiconductor composite catalyst particles (Fe3O4@g-C3N4 composite catalyst) recovered in Example 4 were washed with deionized water and activated at 350~450°C for 2 hours; after activation, they were remixed with EGaIn liquid metal recovered in Example 4 and liquid metal composite catalyst microspheres 8 were prepared according to S5 in Example 2; the residual waste liquid in the magnetic capture and recovery chamber 9 was discharged from the drain port, the chamber was rinsed with deionized water, the liquid metal composite catalyst microspheres 8 were assembled, the water inlet was restarted, and the system resumed continuous operation, realizing the full-process recycling of the flow channel structure, gallium-based liquid metal and magnetic semiconductor composite catalyst.

[0070] Its efficiency in degrading sulfamethoxazole (SMX) remained above 90% of the initial state even after 10 cycles, demonstrating the system's good closed-loop cycle stability.

[0071] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the implementation. The scope of protection of the present invention should be determined by the scope defined in the claims. Other variations or modifications can be made based on the above description. Obvious variations or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A PDMS biomimetic chip system integrally formed using a 3D sacrificial mold, characterized in that, It includes the following functional components: integrated PDMS bionic chip, wastewater inlet, online COD sensor, MCU controller, long-range spiral TENG power generation section, micro electromagnetic valve group, partitioned parallel bionic alveolar reaction array, liquid metal composite catalytic microspheres, magnetic capture and recovery chamber, treated water outlet, pulse energy storage circuit, and parallel induction electrode pair; The integrated PDMS bionic chip has a wastewater inlet and an online COD sensor at its input end; and a treated water outlet at its output end. The integrated PDMS bionic chip is a one-piece cast structure, which integrates a preset microchannel network and functional chambers containing various functional components; the microchannel network extends from the main inlet pipe to branch pipes in stages, and the output ends of each branch pipe are connected to the main outlet pipe. The main inlet pipe is equipped with a long-range spiral TENG power generation section; the branch pipe is equipped with a micro electromagnetic valve group on the pipe section before the branch pipe at the end of the bifurcation. Each micro electromagnetic valve independently controls a parallel branch. Each parallel branch is equipped with a partitioned parallel bionic alveolar reaction array. A magnetic capture and recovery chamber is provided downstream of the partitioned parallel bionic alveolar reaction array. The inner wall of the long-range spiral TENG power generation section is composite with a PTFE friction layer, and the outer wall is wrapped with copper foil electrodes. The copper foil electrodes connect the long-range spiral TENG power generation section to the pulse energy storage circuit. The pulse energy storage circuit is also electrically connected to the parallel induction electrode pair, which is integrated in the PDMS wall on both sides of the partitioned parallel bionic alveolar reaction array. The partitioned parallel biomimetic alveolar reaction array includes alveolar microchambers arranged in a honeycomb three-dimensional pattern. Blind slots are symmetrically arranged on both sides of the alveolar microchambers. Liquid metal gel electrodes are provided inside the blind slots. The liquid metal gel electrodes are composed of gallium-based liquid metal and hydroxyl-terminated polydimethylsiloxane. An insulating wall is provided between the blind slots and the flow channels. The liquid metal composite catalytic microspheres are placed inside the alveolar microchambers; the liquid metal composite catalytic microspheres are gallium-based liquid metal microsphere composites with magnetic semiconductor composite catalyst particles anchored on their surface; The magnetic capture and recovery chamber is equipped with a non-uniform magnetic field and has independent injection and drainage ports. The online COD sensor is located upstream of the fluid in the long-range spiral TENG power generation section. The online COD sensor is electrically connected to the MCU controller via an external thin wire. The MCU controller is connected to the micro electromagnetic valve group via a drive wire.

2. The PDMS bionic chip system according to claim 1, characterized in that, The integrated PDMS bionic chip has a length of 20-200mm, a width of 10-150mm, and a thickness of 5-30mm; it is made of a polymer material with dielectric insulating properties.

3. The PDMS bionic chip system according to claim 1, characterized in that, The diameter of the main inlet pipe is 200~2000μm, and the total number of branch pipes is 10~1000; The number of alveolar microchambers is 10 to 1000, the volume of a single alveolar microchamber is 0.1 to 100 μL, and the inner diameter is 100 to 2000 μm.

4. The PDMS bionic chip system according to claim 1, characterized in that, The thickness of the PTFE friction layer is 10~100μm; The width of the blind groove is 100~300μm; The thickness of the insulating wall between the blind groove and the flow channel is 0.01~0.5mm.

5. The PDMS bionic chip system according to claim 1, characterized in that, The gallium-based liquid metal in the liquid metal gel electrode is 50wt%~95wt%; The mass ratio of gallium-based liquid metal microspheres to magnetic semiconductor composite catalyst particles in the liquid metal composite catalytic microspheres is (5~20):1; the gallium-based liquid metal is selected from one or more of EGaIn, Galinstan and their modified alloys; the magnetic semiconductor composite catalyst is selected from magnetic core-shell structure materials or semiconductor composite materials.

6. The PDMS bionic chip system according to claim 1, characterized in that, The online COD sensor includes a carbon-based working electrode, a noble metal counter electrode, and a silver-based reference electrode. The pulse energy storage circuit includes a rectifier bridge and an energy storage capacitor.

7. The assembly method of the PDMS bionic chip system according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. A water-soluble polyvinyl alcohol sacrificial mold is prepared using stereolithography 3D printing technology. The cavity of the mold defines the microchannel network and functional chambers of each functional component in the integrated PDMS bionic chip. The surface roughness of the channel is controlled at Ra < 0.8 μm. S2, mix polydimethylsiloxane with a curing agent and inject it into the water-soluble polyvinyl alcohol sacrificial mold obtained in S1. Degas, cure and hydrolyze in a vacuum environment to obtain an integrated PDMS bionic chip. S3, liquid metal gel is injected into the blind grooves on both sides of the alveolar microchamber at a flow rate of 0.1~1.0μL / min to obtain a reaction chip with integrated liquid metal gel electrodes; S4, complete the assembly of the sensor and circuit module; S5. Under conditions of temperature of 20~50℃ and ultrasonic power of 100~500W, gallium-based liquid metal microspheres with magnetic semiconductor composite catalyst particles anchored on the surface are ultrasonically treated and washed in a weakly acidic solution of pH=5.0~7.0 to obtain liquid metal composite catalytic microspheres. The liquid metal composite catalytic microspheres are placed inside the alveolar microchambers to complete the overall system assembly.

8. The assembly method according to claim 7, characterized in that, The mass ratio of polydimethylsiloxane to curing agent is (8~15):

1.

9. The method for treating wastewater using the PDMS bionic chip system as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Start the influent micro-pump and set the flow rate to 0.5~5.0 mL / min. The MCU controller adjusts the opening ratio and pulse drive parameters of the zonal parallel bionic alveolar reaction array according to the concentration of the wastewater to be treated. The activation ratio and pulse drive parameters corresponding to the concentration of the wastewater to be treated are set as follows: When the influent COD concentration is ≥180mg / L, it is judged as a high pollution load. The activation ratio of the partitioned parallel bionic alveolar reaction array is 100%, the frequency is 100Hz, the pulse release threshold voltage is set to 100V, and the pulse width is 5ms. When the influent COD concentration is less than 180 mg / L, it is judged as a medium pollution load. The activation ratio of the zonal parallel bionic alveolar reaction array is 50%, the frequency is 50 Hz, the pulse release threshold voltage is set to 50 V, and the pulse width is 10 ms. When the influent COD concentration is ≤50mg / L, it is judged as a low pollution load. The activation ratio of the partitioned parallel bionic alveolar reaction array is 20%, the frequency is 20Hz, the pulse release threshold voltage is set to 20V, and the pulse width is 15ms. Step 2: When the enriched volume of microspheres in the magnetic capture and recovery chamber reaches 60%~90% of the effective volume of the magnetic capture and recovery chamber, stop the water intake and inject the complexing agent buffer solution through the injection port for static soaking; use density difference and magnetic difference to achieve graded recovery, liquid metal microspheres settle to the bottom for collection, and magnetic semiconductor composite catalyst particles float to the upper layer for magnetic collection. Step 3: Discharge the residual waste liquid in the magnetic capture and recovery chamber from the drain port, rinse the chamber with deionized water and restart the water inlet. The system resumes continuous operation, realizing the full-process recycling of the flow channel structure, liquid metal and magnetic semiconductor composite catalyst.

10. The method according to claim 9, characterized in that, The complexing agent buffer solution includes citrate buffer solution, wherein the concentration of the complexing agent in the complexing agent buffer solution is 0.01~1.0 mol / L, and the pH value is 3.0~6.0; The recovered magnetic semiconductor composite catalyst was washed with deionized water and activated at 350~450℃ for 1~4h, then dried and recycled.

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