Silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants, and its manufacturing and application methods.

Abstract

This invention relates to a silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants, and its manufacturing and usage methods. The chip includes a quartz glass layer, a conductive substrate, and a silicon carbide working layer. Unidirectional microchannels are disposed on the surface of the silicon carbide working layer. Encapsulation and current-guiding layers are disposed on the upper and lower sides and left and right ends of the silicon carbide working layer, in addition to the unidirectional microchannels and their inlets and outlets. The quartz glass layer is disposed on both sides of the silicon carbide working layer to clamp it. The conductive substrate is disposed between the silicon carbide working layer and the quartz glass layer to provide current to the silicon carbide working layer. The conductive substrate and the silicon carbide working layer are connected as a single unit along both sides of the silicon carbide working layer via wires. This invention also provides methods for preparing and using the above-mentioned chip. The chip of this invention can minimize system errors and human operational errors, making the screening and evaluation process of oxidants more objective.

Description

Technical Field

[0001] This invention relates to a silicon carbide microchannel array chip and its manufacturing and usage methods for rapidly selecting oxidant types and rapidly evaluating oxidant quality in advanced oxidation technology treatment processes for various types of industrial wastewater, belonging to the field of environmental protection rapid detection accessories. Background Technology

[0002] With the increasing national requirements for industrial wastewater treatment quality, various advanced oxidation processes (AOPs) are widely used to ensure that industrial wastewater meets discharge standards. AOPs target pollutants in wastewater and use ozone, chlorine oxides (such as hypochlorous acid, perchloric acid, and chlorine dioxide), and peroxides (such as hydrogen peroxide and persulfate) as oxidants. Under the influence of various energy factors (such as microwaves, UV light, heat, magnetic / electric fields, and fluid / mechanical stirring) or non-energy factors (such as catalysts, accelerators, and activators), the oxidants oxidize the pollutants, thereby achieving the goal of meeting industrial wastewater discharge standards. From the perspective of the chemical reaction mechanism of the AOP system, various pollutants in the wastewater act as electron donors, providing electrons in the AOP reaction system; various oxidants act as electron acceptors, acquiring electrons; various energy factors increase the proportion and concentration of activated particles in the AOP system; and various non-energy factors mainly reduce the activation energy of the AOP system reaction.

[0003] Oxidant is the primary influencing factor in pollutant removal in an AOP (Anaerobic Processing) system, and it directly determines the cost of wastewater degradation. Therefore, selecting the optimal oxidant while ensuring pollutant degradation is the primary task of AOP technology in achieving industrial wastewater quality standards. However, two challenges remain in screening and evaluating oxidants: ① Before actual engineering applications, AOP technology typically involves preliminary experiments in the laboratory to screen the required AOP oxidants. However, laboratory screening suffers from drawbacks such as high requirements for instrument conditions, relatively cumbersome measurement processes, and high testing intensity, making it difficult to achieve rapid screening; ② After actual engineering applications, differences in production standards, processes, and facilities implemented by manufacturers lead to variations in the quality of similar products. Furthermore, factors such as oxidant storage methods and storage time can cause significant differences in the operating performance and costs of AOP systems, even among the same batch of oxidants.

[0004] Therefore, it is crucial to develop technologies for rapid screening / evaluation of AOP oxidants, shorten the screening cycle for various oxidants in AOP technology by laboratory technicians before engineering use, and improve the quality control capabilities of engineering operators in engineering projects. Summary of the Invention

[0005] To address the lack of readily available testing accessories and the need for rapid screening and quality control of AOP (Anaerobic Optimization) oxidants, this invention proposes a silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants, along with its manufacturing and application methods. This invention provides laboratory analysts and engineering personnel with a novel silicon carbide microchannel array chip for screening and evaluating AOP oxidants. This not only shortens the screening cycle for various AOP oxidants before engineering applications but also effectively improves the quality control capabilities of engineering personnel during engineering processes, ultimately reducing the intensity of screening and testing, as well as the requirements for specific experimental equipment.

[0006] The chip of this invention is characterized by low cost, small size, simple operation, reliable effect, and fast screening and evaluation speed of oxidants. It is of great help to environmental technology practitioners such as industrial wastewater process designers, laboratory testers, and wastewater treatment engineering operation and maintenance personnel in carrying out various tasks such as AOP process technology selection, AOP oxidant screening, and AOP oxidant quality control.

[0007] The technical solution of the present invention is as follows:

[0008] A silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants includes a quartz glass layer, a conductive liner, and a silicon carbide working layer. The surface of the silicon carbide working layer has unidirectional microchannels. Encapsulation and current-guiding layers are provided on the top and bottom sides and left and right ends of the silicon carbide working layer, in addition to the unidirectional microchannels and their inlets and outlets. The quartz glass layer is disposed on both sides of the silicon carbide working layer to hold it in place. The conductive liner is disposed between the silicon carbide working layer and the quartz glass layer to provide current to the silicon carbide working layer. The conductive liner and the silicon carbide working layer are connected as a single unit along both sides of the silicon carbide working layer via wires. The silicon carbide working layer cannot be completely removed when the quartz glass layer or the encapsulation and current-guiding layers are undamaged.

[0009] According to the present invention, the silicon carbide working layer is the core site for screening and determining the quality of AOP oxidant; it is manufactured from micro-nano-scale silicon carbide powder modified with magnetic transition metal gel liquid as the main raw material, through primary pressing, thermosetting treatment, unidirectional microchannel array engraving, purging and other processes.

[0010] Preferably, the raw material for preparing the silicon carbide working layer is a mixture of micro / nano silicon carbide powder and magnetic transition metal gel, wherein the molar ratio of metal ions in the magnetic transition metal gel is Co(II) or Cu(II):Fe(II) or Mn(II):Co(III):Fe(III):Ce(III) of 1.5–2.2:1.5–2.2:0.30–0.33:0.30–0.33:0.30–0.33; more preferably, the concentration of metal cations in the magnetic transition metal gel is 0.4–0.8 mol / L.

[0011] According to the present invention, preferably, the particle size of the micro / nano silicon carbide powder is 10,000 mesh to 15,000 mesh.

[0012] According to the present invention, preferably, the thickness of the silicon carbide working layer is 800μm-1000μm.

[0013] According to the present invention, preferably, the unidirectional microchannel is a Tesla valve structure;

[0014] Preferably, the depth of the unidirectional microchannel is 100-200μm and the width is 200-300μm;

[0015] Preferably, there are four or more unidirectional microchannels, and the distance between the unidirectional microchannels is 3 to 5 mm; more preferably, each unidirectional microchannel is distributed in parallel in the same plane, so that it has the characteristics of a parallel array.

[0016] According to the present invention, preferably, the quartz glass layer is made of high-transmittance borosilicate glass, and is divided into a lower support layer and an upper cover layer;

[0017] More preferably, the thickness of the lower support layer is 3mm, which is used to support the silicon carbide working layer; the thickness of the upper cover layer is 1mm, which is used to cover the silicon carbide working layer; and the length and width dimensions of the quartz glass layer are consistent with the dimensions of the silicon carbide working layer.

[0018] According to the present invention, the conductive liner is located between the silicon carbide working layer and the quartz glass layer, and serves to provide current to the silicon carbide working layer.

[0019] Preferably, the thickness of the conductive liner is 100-150 μm;

[0020] Preferably, the conductive liner is a conductive adhesive formed by dispersing silver-coated copper powder with an average diameter of 12 μm in an ethylene glycol solution containing a silane coupling agent, and then curing it by heat. More preferably, the mass concentration of the silver-coated copper powder is 15-20%, and the concentration of the silane coupling agent is 30-40 g / L.

[0021] Most preferably, the conductive lining forming the conductive liner contains 10% silver in the silver-coated copper powder with an average particle size of 12 μm, and the silane coupling agent is 3-aminopropyltriethoxysilane coupling agent (KH550) with a concentration of 40 g / L.

[0022] According to the present invention, preferably, the encapsulation flow guiding layer is made of polydimethylsiloxane (PDMS) and is located on the upper and lower sides and the left and right ends of the silicon carbide working layer, which serves to protect the silicon carbide working layer and form the microflow inlet and microflow outlet of the unidirectional microchannel of the silicon carbide working layer.

[0023] According to the present invention, a method for preparing a silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants is also provided, comprising the following steps:

[0024] (1) Preparation of a quartz glass support layer with a spin-coated conductive liner

[0025] Using a spin coater, conductive adhesive is evenly spin-coated onto the quartz glass under-support layer in two or more coats and cured in air at 110-120℃. At this time, a conductive liner is formed on the surface of the quartz glass under-support layer. The thickness of the conductive liner formed by each spin coating and curing is 20-30μm. After 4-5 repetitions, a conductive liner with a thickness of 100-150μm can be formed.

[0026] The conductive lining is formed by dispersing silver-coated copper powder with an average diameter of 12 μm in an ethylene glycol solution containing a silane coupling agent.

[0027] (2) Preparation of silicon carbide working layer

[0028] ① In a polytetrafluoroethylene bottle at 80±5℃, using anhydrous ethanol with a DMF concentration of 5~10g / L as a solvent, a clear magnetic transition metal gel solution with a metal cation concentration of 0.4-0.8mol / L and a metal ion molar ratio of Co(II) or Cu(II):Fe(II) or Mn(II):Co(III):Fe(III):Ce(III) of 1.5~2.2:1.5~2.2:0.30~0.33:0.30~0.33:0.30~0.33 was further prepared.

[0029] ② Add 10,000 to 15,000 mesh micro-nano silicon carbide powder to the magnetic transition metal gel liquid at 80±5℃ in ① above in two or more portions, disperse it in an ultrasonic oscillator until the dynamic viscosity coefficient of the solution is 10,000 to 11,000 mPa·s, then stop adding micro-nano silicon carbide powder to obtain silicon carbide working layer precursor gel liquid.

[0030] ③ Keep the ultrasonic vibration and allow the dynamic viscosity coefficient of the silicon carbide working layer precursor solution to cool naturally to 20000~21000mPa·s, then stop cooling and maintain the temperature, and add 10-30g / L of silane coupling agent.

[0031] ④Then, the material in ③ is uniformly spin-coated onto the quartz glass support layer with conductive lining prepared in step (1) in two or more times using a spin coater; after each spin coating, it is dried at 110-120℃ to complete one spin coating-drying cycle; the thickness of the single-layer silicon carbide working layer obtained in each spin coating-drying cycle is 15-20μm, and after multiple repetitions, the final spin coating-drying thickness of the silicon carbide working layer is 800-1000μm;

[0032] ⑤ The silicon carbide working layer is heat-treated in air at 350-500℃ for 1 hour to perform lattice transformation; then cooled to room temperature in air.

[0033] ⑥ Using a laser engraving machine, a unidirectional microchannel array is engraved on the surface of the silicon carbide working layer without the quartz glass overlay. The unidirectional microchannels have a rectangular cross-section, a depth of 100-200μm, and a width of 200-300μm. The distance between the unidirectional microchannels is 3-5mm. The unidirectional microchannels adopt a Tesla valve structure, and the channel design of the Tesla valve structure ensures that it has the characteristic of unidirectional flow. The parallel distribution of multiple independent unidirectional microchannels on the same plane gives it the characteristic of a parallel array.

[0034] ⑦ Cut the silicon carbide working layer into individual wafers, ensuring that each silicon carbide working layer contains at least four unidirectional microchannels. Then, ultrasonically clean it with anhydrous ethanol and blow it with clean air to obtain the silicon carbide working layer.

[0035] (3) Apply conductive adhesive 4-5 times between the unidirectional microchannel arrays of the single silicon carbide working layer, with each application thickness of 20-30μm and the total application thickness of 100-150μm. Then cover it evenly with the quartz glass top cover layer and cure it in air at 110-120℃.

[0036] (4) On both sides of the silicon carbide working layer along the inlet and outlet directions of the unidirectional microchannel array, the wires, conductive substrate and silicon carbide working layer are connected into one piece by overlay welding; then liquid PDMS is used as the encapsulation guide layer to encapsulate the silicon carbide working layer around its perimeter; during the encapsulation process, the port of the unidirectional microchannel of the silicon carbide working layer is kept open to the outside, and the wires are kept open to the external DC power supply, thus completing the preparation of the silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidant.

[0037] According to the present invention, the preferred preparation parameters for the preparation of the silicon carbide working layer in step (2) are as follows:

[0038] ① In a polytetrafluoroethylene bottle at 82.5℃, using anhydrous ethanol with a DMF concentration of 8 g / L as the solvent, a clear magnetic transition metal gel solution with a metal cation concentration of 0.8 mol / L and a metal ion molar ratio of Co(II):Fe(II):Co(III):Fe(III):Ce(III) of 2.0:2.0:0.35:0.35:0.3 was prepared.

[0039] ② Add 13000 mesh micro-nano silicon carbide powder to an 82.5℃ organometallic solution in stages and multiple times, and disperse it in an ultrasonic oscillator until the dynamic viscosity coefficient of the solution is 10500 mPa·s, then stop adding micro-nano silicon carbide powder. At this time, the silicon carbide working layer precursor colloid is obtained.

[0040] ③ Keep the ultrasonic vibration and allow the dynamic viscosity coefficient of the silicon carbide working layer precursor solution to cool naturally to 20500 mPa·s. Stop cooling and maintain the temperature. Randomly add 15 g / L of 3-aminopropyltriethoxysilane coupling agent (KH550).

[0041] ④ Subsequently, the material from ③ was uniformly spin-coated onto the quartz glass support layer pre-coated with a conductive liner using a spin coater in multiple applications. After each spin coating of the silicon carbide working layer precursor adhesive, it was immediately dried at 115°C to complete one spin-coating-drying cycle. The thickness of the single-layer silicon carbide working layer obtained in each spin-coating-drying cycle was 20 μm. After repeating 40, 45, and 50 cycles, the spin coating thicknesses were 800, 900, and 1000 μm, respectively.

[0042] ⑤ Place the silicon carbide working layer in an air environment at 450℃ for 1 hour to perform lattice transformation, and then cool the air environment to room temperature;

[0043] ⑥ Using a laser engraving machine, a unidirectional microchannel array is engraved on the surface of the silicon carbide working layer without the quartz glass overlay. The microchannels have a rectangular cross-section, a depth of 150μm, and a width of 250μm. The channel spacing is not less than 3mm. The channel design has a Tesla valve structure.

[0044] ⑦ Use a wafer dicing machine to cut the silicon carbide working layer into single pieces with a width × length of 3cm × 6cm and a channel spacing of 4mm. Each piece of unidirectional microchannel array contains 7 unidirectional microchannels. Then, use anhydrous ethanol for ultrasonic cleaning and use clean air to blow away the silicon carbide working layer.

[0045] According to the present invention, a method for using the silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants is also provided. When used for screening AOP oxidants, the working steps are as follows:

[0046] ① Connect the external DC power supply (5V, 0~300mA) with adjustable current to the external copper wire to control the temperature of the silicon carbide microchannel array chip to 80±5℃;

[0047] ② Prepare pure water, pretreated industrial wastewater after removing suspended solids and impurities by filtering with glass fiber, oxidant solution A, and oxidant solution B. Select molar concentration or mass concentration index as needed to keep oxidant solution A and oxidant solution B at the same concentration.

[0048] ③ A 7-channel micro-syringe pump will be used, wherein: channel A is injected with pure water; channel B is injected with pretreated industrial wastewater; channel C is injected with the first oxidant solution; channel D is injected with the second oxidant; channel E is injected with a 1:1 volume ratio of oxidant A solution and pretreated industrial wastewater mixed solution; channel F is injected with a 1:1 volume ratio of oxidant B solution and pretreated industrial wastewater mixed solution; and channel G is injected with a 1:1:2 volume ratio of oxidant A solution, oxidant B solution and pretreated industrial wastewater mixed solution. The retention time of the fluid in the seven channels is 20 min.

[0049] ④ When UV light enhancement reaction is applied to the side of the silicon carbide microchannel array chip with a quartz glass capping layer, the fluid retention time can be appropriately shortened, but the overall time should not be less than 10 minutes.

[0050] ⑤ Collect the reacted liquid from 7 channels and simultaneously test the spectral absorption of the liquid under UV254nm and UV460nm ultraviolet light. Using channel A as a blank, channel B as a baseline, channels C and D as calibration, channels E and F as controls, and channel G as a reference, the individual effects of oxidant A and oxidant B, as well as the basis for whether synergistic selection exists, can be obtained.

[0051] According to the present invention, a method for using the silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants is also provided. When used for quality control of AOP oxidants, the working steps are the same as the screening steps of AOP oxidants, except that: oxidant A is selected to meet national standards or is an oxidant used for the first time, and oxidant B is selected to be the same type as oxidant A that will be subject to quality control.

[0052] The technical features and beneficial effects of this invention are as follows:

[0053] 1. Silicon carbide, as a third-generation semiconductor material, possesses high hardness and strength, and is resistant to corrosion, acids, alkalis, and oxidation. Furthermore, its high efficiency in converting electrical energy into heat makes it an ideal material for heating components. In addition, silicon carbide forms a Si-C sp3 hybrid lattice structure, where the π-π bonds formed by the PN junctions and lattice dislocations within the silicon carbide lattice create C-C bonds.※ The structure exhibits significant non-radical activation capabilities against commonly used oxidants in AOP. The M(II) / M(III) divalent groups in the magnetic medium of the silicon carbide working layer possess extremely strong electron-transfer capabilities due to their variable valence, resulting in strong free radical activation of common AOP oxidants such as PS, O3, hydrogen peroxide, and chlorine-containing oxidants. These two effects are the fundamental reason for the non-energy-based acceleration of oxidant activity.

[0054] 2. The engraving of unidirectional microchannels in silicon carbide results in a significantly higher resistance near the unidirectional microchannels compared to areas without channels. This leads to a noticeable local thermal effect, and the accumulation of heat further promotes the release of oxidant capacity, thus shortening the reaction time. When enhanced by external UV light, the photon energy of its specific frequency further excites and enhances the full release of oxidant capacity. The local thermal effect and UV-enhanced light radiation are the fundamental reasons why energy factors accelerate the manifestation of oxidant capacity.

[0055] 3. This invention uses UV 254nm and UV 460nm simultaneously to test samples, which can fully demonstrate the degradation effect of oxidants on pollutants in wastewater. Correspondingly, the unidirectional microchannel pipeline design strictly adopts a blank, benchmark, calibration, and control approach. That is, every additional 3 channels allows for the screening and evaluation of another oxidant. Therefore, using 4 or 7 channels can achieve the screening and evaluation of one or two oxidants. This approach can minimize systematic errors and human operational errors, making the oxidant screening and evaluation process more objective. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the main structure of the silicon carbide microchannel array chip used for rapid screening and evaluation of oxidants according to the present invention.

[0057] Figure 2 This is a schematic diagram of the explosive decomposition of the silicon carbide microchannel array chip used for rapid screening and evaluation of oxidants according to the present invention.

[0058] Figure 3 This is a schematic diagram of the Tesla valve structure of the silicon carbide microchannel array chip used for rapid screening and evaluation of oxidants according to the present invention.

[0059] Figure 4 The images show the XRD patterns of silicon carbide working layers of different thicknesses in the silicon carbide microchannel array chip prepared in Example 3 of Experiment 1 of this invention for rapid screening and evaluation of oxidants.

[0060] Figure 5These are SEM images and EDX-mapping images of silicon carbide working layers of different thicknesses in the silicon carbide microchannel array chip prepared in Example 3 of Experiment 1 of this invention for rapid screening and evaluation of oxidants.

[0061] Figure 6 The images show the Raman spectra of silicon carbide working layers of different thicknesses in the silicon carbide microchannel array chip prepared in Example 3 of Experiment 1 of this invention for rapid screening and evaluation of oxidants.

[0062] The structure includes: 1. Quartz glass layer; 2. Conductive liner; 3. Silicon carbide working layer; 4. Encapsulation and current guiding layer; 5. Unidirectional microchannel; 6. Conductor. Detailed Implementation

[0063] The present invention will be further described below with reference to specific embodiments and accompanying drawings, but is not limited thereto.

[0064] Example 1

[0065] like Figure 1-3 As shown, a silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants includes a quartz glass layer 1, a conductive liner 2, and a silicon carbide working layer 3. Unidirectional microchannels 5 are formed on the surface of the silicon carbide working layer 3. Encapsulation and current-guiding layers 4 are provided on the top and bottom sides and left and right ends of the silicon carbide working layer 3, in addition to the unidirectional microchannels 5 and their inlets and outlets. The quartz glass layer 1 is disposed on both sides of the silicon carbide working layer 3 to clamp it. The conductive liner 2 is disposed between the silicon carbide working layer 3 and the quartz glass layer 1 to provide current to the silicon carbide working layer 3. The conductive liner 2 and the silicon carbide working layer 3 are connected as a single unit along both sides of the silicon carbide working layer 3 via wires 6. The silicon carbide working layer 3 cannot be completely removed when the quartz glass layer 1 or the encapsulation and current-guiding layers 4 are undamaged.

[0066] Example 2

[0067] The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants as described in Example 1 differs in that:

[0068] The silicon carbide working layer 3 is prepared from a mixture of micro / nano silicon carbide powder and magnetic transition metal gel. The molar ratio of metal ions in the magnetic transition metal gel is Co(II) or Cu(II):Fe(II) or Mn(II):Co(III):Fe(III):Ce(III) = 1.5–2.2:1.5–2.2:0.30–0.33:0.30–0.33:0.30–0.33; the concentration of metal cations in the magnetic transition metal gel is 0.4–0.8 mol / L. The particle size of the micro / nano silicon carbide powder is 10,000 mesh to 15,000 mesh.

[0069] The thickness of the silicon carbide working layer 3 is 800μm-1000μm, and the unidirectional microchannel 5 is a Tesla valve structure; the depth of the unidirectional microchannel 5 is 100-200μm, and the width is 200-300μm; there are four or more unidirectional microchannels 5, and the distance between the unidirectional microchannels 5 is 3-5mm; each unidirectional microchannel 5 is distributed in parallel in the same plane, giving it the characteristics of a parallel array.

[0070] The quartz glass layer 1 is made of high-transmittance borosilicate glass and consists of a lower support layer and an upper cover layer.

[0071] The lower support layer is 3mm thick and is used to support the silicon carbide working layer 3; the upper cover layer is 1mm thick and is used to cover the silicon carbide working layer 3; the length and width dimensions of the quartz glass layer 1 are consistent with the dimensions of the silicon carbide working layer 3.

[0072] The conductive liner 2 is located between the silicon carbide working layer 3 and the quartz glass layer 1, and serves to provide current to the silicon carbide working layer 3. The thickness of the conductive liner 2 is 100-150 μm. The conductive liner 2 is a conductive adhesive formed by dispersing silver-coated copper powder with an average diameter of 12 μm in an ethylene glycol solution containing a silane coupling agent, and then curing it by thermosetting. More preferably, the mass concentration of the silver-coated copper powder is 15-20%, and the concentration of the silane coupling agent is 30-40 g / L. Most preferably, the silver content of the silver-coated copper powder with an average particle size of 12 μm in the conductive adhesive forming the conductive liner 2 is 10%, and the silane coupling agent is 3-aminopropyltriethoxysilane coupling agent (KH550) with a concentration of 40 g / L.

[0073] The encapsulation flow guiding layer 4 is made of polydimethylsiloxane (PDMS) and is located on the upper and lower sides and left and right ends of the silicon carbide working layer 3. It serves to protect the silicon carbide working layer 3 and form the microflow inlet and microflow outlet of the unidirectional microchannel of the silicon carbide working layer 3.

[0074] Example 3

[0075] The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants described in Example 1 or 2 comprises four parts: a silicon carbide working layer 3, a quartz glass layer 1, a conductive liner 2, and a packaging current-conducting layer 4. The corresponding exploded-out assembly diagram is shown below. Figure 2 As shown, the preparation method includes the following steps:

[0076] (1) Preparation of a quartz glass support layer with a spin-coated conductive liner

[0077] Using a spin coater, conductive adhesive is uniformly spin-coated onto the quartz glass under-support layer 1 in two or more coats and cured in air at 110-120℃. At this time, a conductive backing layer 2 is formed on the surface of the quartz glass under-support layer 1. The thickness of the conductive backing layer 2 formed by each spin coating and curing is 20-30μm. After 4-5 repetitions, a conductive backing layer 2 with a thickness of 100-150μm can be formed.

[0078] The conductive lining is formed by dispersing silver-coated copper powder with an average diameter of 12 μm in an ethylene glycol solution containing a silane coupling agent.

[0079] (2) Preparation of silicon carbide working layer

[0080] ① In a polytetrafluoroethylene bottle at 80±5℃, using anhydrous ethanol with a DMF concentration of 5~10g / L as a solvent, a clear magnetic transition metal gel solution with a metal cation concentration of 0.4-0.8mol / L and a metal ion molar ratio of Co(II) or Cu(II):Fe(II) or Mn(II):Co(III):Fe(III):Ce(III) of 1.5~2.2:1.5~2.2:0.30~0.33:0.30~0.33:0.30~0.33 was further prepared.

[0081] ② Add 10,000 to 15,000 mesh micro-nano silicon carbide powder to the magnetic transition metal gel liquid at 80±5℃ in ① above in two or more portions, disperse it in an ultrasonic oscillator until the dynamic viscosity coefficient of the solution is 10,000 to 11,000 mPa·s, then stop adding micro-nano silicon carbide powder to obtain silicon carbide working layer precursor gel liquid.

[0082] ③ Keep the ultrasonic vibration and allow the dynamic viscosity coefficient of the silicon carbide working layer precursor solution to cool naturally to 20000~21000mPa·s, then stop cooling and maintain the temperature, and add 10-30g / L of silane coupling agent.

[0083] ④Then, the material in ③ is uniformly spin-coated onto the quartz glass support layer with conductive lining prepared in step (1) in two or more times using a spin coater; after each spin coating, it is dried at 110-120℃ to complete one spin coating-drying cycle; the thickness of the single-layer silicon carbide working layer obtained in each spin coating-drying cycle is 15-20μm, and after multiple repetitions, the final spin coating-drying thickness of the silicon carbide working layer 3 is 800-1000μm;

[0084] ⑤ The silicon carbide working layer 3 was heat-treated in an air environment at 350-500℃ for 1 hour to perform lattice transformation; then cooled to room temperature in an air atmosphere.

[0085] ⑥ Using a laser engraving machine, an array of unidirectional microchannels 5 is engraved on the surface of the silicon carbide working layer 3, which is not covered by quartz glass and has a rectangular cross-section, a depth of 100-200μm, and a width of 200-300μm; the distance between the unidirectional microchannels 5 is 3-5mm; the unidirectional microchannels 5 adopt a Tesla valve structure, and the channel design of the Tesla valve structure ensures that it has the characteristic of unidirectional flow; the parallel distribution of multiple independent unidirectional microchannels 5 on the same plane gives it the characteristic of a parallel array;

[0086] ⑦ Cut the silicon carbide working layer 3 into individual pieces, ensuring that each silicon carbide working layer 3 contains at least four unidirectional microchannels 5. Then, ultrasonically wash with anhydrous ethanol and blow with clean air to obtain the silicon carbide working layer 3.

[0087] (3) Apply conductive adhesive 4-5 times between the unidirectional microchannels 5 array spacing of the single silicon carbide working layer 3, with each application thickness of 20-30μm and the total application thickness of 100-150μm. Then cover it evenly with the quartz glass cover layer 1 and cure it in an air atmosphere at 110-120℃.

[0088] (4) On both sides of the silicon carbide working layer 3 along the inlet and outlet directions of the unidirectional microchannel 5 array, the three parts of the wire 6, conductive liner 2 and silicon carbide working layer 3 are connected into one piece by overlay welding; then liquid PDMS is used as the encapsulation guide layer 4 to encapsulate the silicon carbide working layer 3 around its perimeter; during the encapsulation process, the port of the unidirectional microchannel 5 of the silicon carbide working layer 3 is kept open to the outside world, and the wire 6 is kept open to the external DC power supply, thus completing the preparation of the silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidant.

[0089] Example 4

[0090] The silicon carbide microchannel array chip prepared in Example 3 for rapid screening and evaluation of oxidants was used for screening AOP oxidants. Taking the silicon carbide microchannel array chip containing 7 unidirectional microchannels (named channels A, B, C, D, E, F, and G, respectively) prepared according to the method of Example 3 as an example, its working method when used for screening AOP oxidants is as follows:

[0091] ① Connect the external DC power supply (5V, 0~300mA) with adjustable current to the external copper wire to control the temperature of the silicon carbide microchannel array chip to 80±5℃;

[0092] ② Prepare pure water, pretreated industrial wastewater after removing suspended solids and impurities by filtering with glass fiber, oxidant solution A, and oxidant solution B. Select molar concentration or mass concentration index as needed to keep oxidant solution A and oxidant solution B at the same concentration.

[0093] ③ A 7-channel micro-syringe pump will be used, wherein: channel A is injected with pure water; channel B is injected with pretreated industrial wastewater; channel C is injected with the first oxidant solution; channel D is injected with the second oxidant; channel E is injected with a 1:1 volume ratio of oxidant A solution and pretreated industrial wastewater mixed solution; channel F is injected with a 1:1 volume ratio of oxidant B solution and pretreated industrial wastewater mixed solution; and channel G is injected with a 1:1:2 volume ratio of oxidant A solution, oxidant B solution and pretreated industrial wastewater mixed solution. The retention time of the fluid in the seven channels is 20 min.

[0094] ④ When UV light enhancement reaction is applied to the side of the silicon carbide microchannel array chip with a quartz glass capping layer, the fluid retention time can be appropriately shortened, but the overall time should not be less than 10 minutes.

[0095] ⑤ Collect the reacted liquid from all 7 channels and test its spectral absorption under 254nm and 460nm ultraviolet light. Use channel A as a blank, channel B as a baseline, channels C and D for calibration, channels E and F as controls, and channel G as a reference. This will provide evidence of the individual effectiveness of oxidants A and B, and whether synergistic selection exists.

[0096] Example 5

[0097] A silicon carbide microchannel array chip for rapid screening and evaluation of oxidants can be used for the evaluation of AOP oxidants. Again, taking the silicon carbide microchannel array chip containing seven unidirectional microchannels (named channels A, B, C, D, E, F, and G, respectively) prepared under preferred conditions in Example 3 as an example, the difference in its working method when used for the quality control of AOP oxidants is that oxidant A is selected as either conforming to national standards or being used for the first time, and oxidant B is selected as the same type of oxidant as A that will be subject to quality control. Other working steps are the same as the screening steps for AOP oxidants in Example 4.

[0098] Test case

[0099] The silicon carbide working layer prepared in Example 3 is rich in body-centered Co3O4 and Fe3O4 magnetic activation crystals. The silicon carbide working layers with spin coating thicknesses of 800, 900 and 1000 μm were obtained by spin coating 40, 45 and 50 times.

[0100] The XRD pattern of the silicon carbide working layer is as follows: Figure 4 As shown, from top to bottom, these correspond to 1000μm, 900μm, and 800μm respectively. (From...) Figure 4It can be seen that obvious Co3O4 and Fe3O4 layer magnetic active functional materials were formed in the three working layers of different thicknesses. Strong characteristic diffraction peaks appeared at diffraction angles of 2θ = 18.88° (111), 30.92° (220), 36.56° (311), 44.20° (400), 58.84° (511), and 64.62° (440), the positions of which perfectly match the standard cards for magnetic crystals Co3O4 and Fe3O4, further confirming that the main components of the synthesized Cu / Fe magnetic activated crystal are Co3O4 and Fe3O4. In addition, the sharpness of the main characteristic diffraction peaks indicates good crystallinity. Figure 4 It can also be seen that the spin-coating thickness of the Cu / Fe magnetically activated crystal does not affect the 2θ position of the XRD characteristic diffraction peaks, maintaining a good peak shape structure. With increasing spin-coating thickness, the XRD characteristic peaks of the Cu / Fe magnetically activated crystal become sharper, and its crystallinity increases with increasing spin-coating thickness. The working layer is rich in Co. 2+ / Co 3+ and Fe 2+ / Fe 3+ Two types of M 2+ / M 3+ The metal functional combination acts as an electronic conductor to activate the oxidant.

[0101] SEM images of the silicon carbide working layer, such as... Figure 5 As shown, a, b, and c correspond to thicknesses of 800 μm, 900 μm, and 1000 μm, respectively. With increasing coating thickness, the working layer becomes increasingly dense. The EDX-mapping image with d representing 800 μm shows this. Figure 4 The tested functional substances are uniformly distributed on the working layer.

[0102] Raman spectra of the metal functional groups in the silicon carbide working layer were tested, such as... Figure 6 As stated above. By Figure 6 It can be seen that at approximately 190cm -1 and 500cm -1 The peaks around the left and right can be attributed to Co-O deformation vibrations. (535-582 cm⁻¹) -1 Another peak at 680 cm⁻¹ belongs to a combination of Co-O and Fe-O deformation vibrations. -1 The strong peaks at these locations are related to the contraction of Fe-O bonds. This further confirms the presence of the active component in the working layer.

Claims

1. A silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants, characterized in that, The chip includes a quartz glass layer, a conductive liner, and a silicon carbide working layer. The surface of the silicon carbide working layer is provided with unidirectional microchannels. In addition to the unidirectional microchannels and their inlets and outlets, encapsulation current guiding layers are provided on the upper and lower sides and the left and right ends of the silicon carbide working layer. The quartz glass layer is disposed on both sides of the silicon carbide working layer to clamp the silicon carbide working layer. The conductive liner is disposed between the silicon carbide working layer and the quartz glass layer to provide current to the silicon carbide working layer. The conductive liner and the silicon carbide working layer are connected as a whole along both sides of the silicon carbide working layer by wires. The silicon carbide working layer is prepared from a mixture of micro / nano silicon carbide powder and magnetic transition metal gel, wherein the molar ratio of metal ions in the magnetic transition metal gel is Co( ) or Cu( ): Fe( ) or Mn( ): Co( ): Fe( ):Ce( The values ​​are 1.5~2.2:1.5~2.2:0.30~0.33:0.30~0.33:0.30~0.

33.

2. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The concentration of metal cations in the magnetic transition metal gel is 0.4-0.8 mol / L.

3. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The particle size of the micro / nano silicon carbide powder is 10,000 mesh to 15,000 mesh.

4. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The thickness of the silicon carbide working layer is 800μm-1000μm.

5. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The unidirectional microchannel described herein is a Tesla valve structure.

6. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The depth of the unidirectional microchannel is 100-200μm and the width is 200-300μm.

7. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, There are four or more unidirectional microchannels, with a distance of 3-5 mm between them, and each unidirectional microchannel is distributed in parallel in the same plane.

8. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The quartz glass layer is made of high-transmittance borosilicate glass and consists of a lower support layer and an upper cover layer.

9. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 8, characterized in that, The lower support layer is 3mm thick and is used to support the silicon carbide working layer; the upper cover layer is 1mm thick and is used to cover the silicon carbide working layer.

10. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The thickness of the conductive liner is 100-150 μm.

11. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 10, characterized in that, The conductive liner is a conductive adhesive formed by dispersing silver-coated copper powder with an average diameter of 12 μm in an ethylene glycol solution containing a silane coupling agent, and then curing it by heat.

12. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 11, characterized in that, The mass concentration of silver-coated copper powder is 15-20%, and the concentration of silane coupling agent is 30-40 g / L.

13. The silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to claim 1, characterized in that, The encapsulation and flow guiding layer is made of polydimethylsiloxane (PDMS) and is located on the upper and lower sides and the left and right ends of the silicon carbide working layer. It serves to protect the silicon carbide working layer and form the microflow inlet and microflow outlet of the unidirectional microchannel with the silicon carbide working layer.

14. The method for preparing a silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to any one of claims 1-13, comprising the following steps: (1) Preparation of a support layer for quartz glass with a conductive liner spin-coated Using a spin coater, conductive adhesive is evenly spin-coated onto the quartz glass under-support layer in two or more coats and cured in air at 110-120℃. At this time, a conductive liner is formed on the surface of the quartz glass under-support layer. The thickness of the conductive liner formed by each spin coating and curing is 20-30μm. After 4-5 repetitions, a conductive liner with a thickness of 100-150μm can be formed. The conductive lining is formed by dispersing silver-coated copper powder with an average diameter of 12 μm in an ethylene glycol solution containing a silane coupling agent. (2) Preparation of silicon carbide working layer ① In a polytetrafluoroethylene bottle at 80±5℃, using anhydrous ethanol with a DMF concentration of 5~10g / L as a solvent, further prepare... Prepare metal cations with a concentration of 0.4-0.8 mol / L and a metal ion molar ratio of Co( ) or Cu( ): Fe( ) or Mn( ): Co( ): Fe( Ce( A clear magnetic transition metal gel with a molecular weight ratio of 1.5 ~ 2.2: 1.5 ~ 2.2: 0.30 ~ 0.33: 0.30 ~ 0.33: 0.30 ~ 0.33; ② Add 10000~15000 mesh micro / nano silicon carbide powder to the above ① magnetic transition at 80±5℃ in two or more batches. The metal gel liquid is dispersed in an ultrasonic oscillator until the dynamic viscosity coefficient of the solution is 10000~11000 mPa·s, then the addition of micro-nano silicon carbide powder is stopped to obtain the silicon carbide working layer precursor liquid. ③ Maintain ultrasonic oscillation and allow the silicon carbide working layer precursor adhesive to cool naturally until the dynamic viscosity coefficient reaches [value missing]. 20000~21000 mPa·s, stop cooling and maintain temperature, add 10-30 g / L of silane coupling agent; ④Then, the material in ③ is uniformly spin-coated onto the quartz glass support layer with conductive lining prepared in step (1) in two or more times using a spin coater; after each spin coating, it is dried at 110-120℃ to complete one spin coating-drying cycle; the thickness of the single-layer silicon carbide working layer obtained in each spin coating-drying cycle is 15~20μm, and after multiple repetitions, the final spin coating-drying thickness of the silicon carbide working layer is 800-1000μm; ⑤ The silicon carbide working layer is heat-treated in air at 350-500℃ for 1 hour to perform lattice transformation; then cooled to room temperature in air. ⑥ Using a laser engraving machine, a unidirectional microchannel array is engraved on the surface of the silicon carbide working layer without the quartz glass overlay. The unidirectional microchannels have a rectangular cross-section, a depth of 100-200μm, and a width of 200-300μm. The distance between the unidirectional microchannels is 3-5mm. The unidirectional microchannels adopt a Tesla valve structure, and the channel design of the Tesla valve structure ensures that it has the characteristic of unidirectional flow. The parallel distribution of multiple independent unidirectional microchannels on the same plane gives it the characteristic of a parallel array. ⑦ Cut the silicon carbide working layer into individual wafers, ensuring that each silicon carbide working layer contains at least four unidirectional microchannels. Then, ultrasonically clean it with anhydrous ethanol and blow it with clean air to obtain the silicon carbide working layer. (3) Apply conductive adhesive 4-5 times between the unidirectional microchannel arrays of the single silicon carbide working layer, with each application having a thickness of 20-30 μm and a total application thickness of 100-150 μm. Then, cover the layer evenly with a quartz glass top cover and cure in an air atmosphere at 110-120℃. (4) On both sides of the silicon carbide working layer along the inlet and outlet directions of the unidirectional microchannel array, the wires, conductive substrate and silicon carbide working layer are connected as one piece by overlay welding; then liquid PDMS is used as the encapsulation guide layer to encapsulate the silicon carbide working layer around its perimeter; during the encapsulation process, the port of the unidirectional microchannel of the silicon carbide working layer is kept open to the outside, and the wires are kept open to be connected to an external DC power supply, thus completing the preparation of silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidant.

15. The method of using the silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidants according to any one of claims 1-13, when used for screening AOP oxidants, comprises the following steps: ① Connect the external DC power supply (5V, 0~300mA) with adjustable current to the external copper wire to control the temperature of the silicon carbide microchannel array chip to 80±5℃; ② Prepare pure water, pretreated industrial wastewater after removing suspended solids and impurities by filtering with glass fiber, oxidant solution A, and oxidant solution B. Select molar concentration or mass concentration index as needed to keep oxidant solution A and oxidant solution B at the same concentration. ③ A 7-channel micro-needle syringe pump will be used, wherein: Channel A is injected with pure water; Channel B is injected with pretreated industrial wastewater; Channel C is injected with the first type of oxidant solution; Channel D is injected with the second type of oxidant; Channel E is injected with a 1:1 volume ratio of oxidant solution A and pretreated industrial wastewater; Channel F is injected with a 1:1 volume ratio of oxidant solution B and pretreated industrial wastewater; Channel G is injected with a 1:1:2 volume ratio of oxidant solution A, oxidant solution B and pretreated industrial wastewater. The retention time of the fluids in the seven channels is 20 minutes. ④ When UV light enhancement reaction is applied to the side of the silicon carbide microchannel array chip with a quartz glass capping layer, the fluid retention time can be appropriately shortened, but the overall time should not be less than 10 minutes. ⑤ Collect the liquid after reaction in 7 channels and test the spectral absorption of the liquid under ultraviolet light at 254nm and 460nm; using the index of channel A as blank, channel B as reference, channels C and D as calibration, channels E and F as control, and channel G as reference, the individual effects of oxidant A and oxidant B and the basis for whether there is synergistic selection can be obtained.

16. The method of using silicon carbide microchannel array chip for rapid screening / evaluation of AOP oxidant as described in any one of claims 1-13, when used for quality control of AOP oxidant, the working steps are the same as the screening steps of AOP oxidant as described in claim 15, except that: oxidant A is selected to be an oxidant that meets national standards or is being used for the first time, and oxidant B is selected to be the same type of oxidant as A that will be subject to quality control.

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