A microfluidic device and method for real-time monitoring of organic pollutant degradation

Abstract

The present application belongs to the technical field of monitoring degradation of organic pollutants, and particularly relates to a microfluidic device and method for real-time monitoring of degradation of organic pollutants. The present application comprises a sample inlet unit for independently flowing organic pollutant solution and oxidant solution, the sample inlet unit being connected to a premixing flow channel; a catalytic reaction microfluidic channel unit comprising a catalytic reaction microfluidic channel reaction chamber, the catalytic reaction microfluidic channel reaction chamber being provided with a catalyst, the catalytic reaction microfluidic channel reaction chamber being in communication with the premixing flow channel; and a monitoring unit arranged on the catalytic reaction microfluidic channel reaction chamber, the reaction liquid being introduced into the monitoring unit after flowing through the catalytic reaction microfluidic channel reaction chamber. The present application is based on the mode of "catalytic reaction-real-time detection-dynamic mechanism analysis", and can realize real-time characterization of the degradation process of organic pollutants under the conditions of continuous flow, microscale and low sample consumption, and synchronously acquire time sequence change information of intermediate products, so as to reveal the catalytic degradation kinetics and reaction path of the target organic pollutants.

Description

Technical Field

[0001] This invention belongs to the field of organic pollutant degradation monitoring technology, specifically relating to a microfluidic device and method for real-time monitoring of organic pollutant degradation. Background Technology

[0002] Chlorinated hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) are typical recalcitrant organic pollutants in the environment. Trichloroethylene is volatile, mobile, and biotoxic, while PAHs such as BaP, BaA, DaA, and IcdP are highly hydrophobic, have strong mutagenic / carcinogenic risks, and high environmental persistence. For these pollutants, advanced oxidation technologies based on persulfate (PMS) activation have attracted widespread attention due to their ability to generate reactive species such as sulfate radicals, hydroxyl radicals, and singlet oxygen in situ.

[0003] For chlorinated hydrocarbons and polycyclic aromatic hydrocarbons, researchers often activate persulfates with transition metals or metal oxides to achieve organic matter degradation. The core of this approach lies in the catalytic material itself, such as heterogeneous catalytic persulfate Fenton oxidation for water treatment, and supported Co-based catalytic membranes or materials. However, real-time mechanistic analysis of the organic pollutant degradation process is lacking. For PMS activation systems, batch beaker or fixed-bed reactors are often used to evaluate catalyst performance. This usually only provides information on the removal rate or endpoint product at a specific time point, making it difficult to capture the continuous process of pollutant decay, intermediate product formation-conversion-disappearance, and catalytic interface state changes on the same spatiotemporal scale. For catalytic oxidation reactions involving short-lived active species and transient intermediates, the true reaction pathway is easily obscured by mixing lag, sampling delay, sample transfer loss, and insufficient temporal resolution. Summary of the Invention

[0004] The purpose of this invention is to provide a microfluidic device and method for real-time monitoring of organic pollutant degradation. This method achieves rapid contact between the PMS (particulate matter analyzer), pollutants, and catalytically active sites through short diffusion distances and high interfacial areas at the microfluidic scale. Simultaneously, by utilizing a continuous flow approach, the traditional discontinuous analysis of "sampling-transfer-offline detection" is transformed into a continuous "introduction-reaction-direct detection" chain. This enables real-time characterization of the degradation process of organic pollutants such as trichloroethylene, BaP, BaA, DaA, and IcdP under continuous flow, microscale, and low sample consumption conditions, while simultaneously acquiring temporal changes in intermediate products, thereby revealing the catalytic degradation kinetics and reaction pathways of the target organic pollutants.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] The first objective of this invention is to provide a microfluidic device for real-time monitoring of the degradation of organic pollutants, comprising: The injection unit is used for the independent flow of organic pollutant solution and oxidant solution. The injection unit is connected to the premixing channel, which is used to mix and contact the pollutant solution and oxidant solution.

[0007] The catalytic reaction microfluidic unit includes a catalytic reaction microfluidic reaction chamber, in which a catalyst is provided for catalytic degradation of organic pollutants to form a reaction solution. The catalytic reaction microfluidic reaction chamber is connected to a premixed channel.

[0008] The monitoring unit is located on the catalytic reaction microchannel reaction chamber. After the reaction liquid flows through the catalytic reaction microchannel reaction chamber, it is introduced into the monitoring unit in a staggered manner for real-time monitoring and characterization of the degradation of organic pollutants.

[0009] Furthermore, the catalyst is a Co-doped iron oxide, which is coated on the surface of a porous support to form an immobilized catalytic interface; or loaded on a micropillar array, microbead bed or three-dimensional porous framework; or formed into a detachable catalytic module.

[0010] Furthermore, the monitoring unit includes an infrared light-transmitting window, an infrared light source, and an infrared detector. Monitoring holes are symmetrically provided on the opposite two side walls of the catalytic reaction microchannel reaction chamber. The infrared light-transmitting window is located inside the monitoring hole. The infrared light source and the infrared detector are respectively located at the two ends of the axis of the monitoring hole. The detection beam emitted by the infrared light source passes through one monitoring window, the inside of the microchannel reaction chamber, and the other monitoring window in sequence, and is received by the infrared detector.

[0011] Furthermore, the injection unit includes a contaminant injection unit and an oxidant injection unit, both of which are connected to a flow control unit, used to control and adjust the flow rates of the contaminant solution and the oxidant solution, respectively.

[0012] Furthermore, the injection unit is connected to a flow control unit to control and regulate the flow rates of the contaminant solution and the oxidant solution.

[0013] Furthermore, the catalytic reaction microchannel reaction chamber is equipped with cover plates at both the top and bottom, forming a closed microchannel between the cover plates.

[0014] Furthermore, at least one monitoring unit is provided along the length of the catalytic reaction microchannel reaction chamber.

[0015] Furthermore, when multiple monitoring units are provided, they are arranged at intervals along the length of the catalytic reaction microchannel reaction chamber to sequentially detect the reaction liquid at different reaction time points.

[0016] Furthermore, the oxidant is persulfate or hydrogen peroxide, and the organic pollutant is chlorinated hydrocarbons and / or polycyclic aromatic hydrocarbons.

[0017] A second objective of this invention is to provide a method for real-time monitoring of the degradation of organic pollutants, utilizing the aforementioned microfluidic device, comprising the following steps: The pollutant solution and oxidant solution are introduced separately through the injection unit. The pollutant solution and oxidant solution are mixed and contacted through the premixing channel, and then flow into the catalytic reaction microchannel reaction chamber to catalytically degrade organic pollutants to form a reaction solution. The reaction solution is introduced into the monitoring unit in a staggered manner to monitor and characterize the degradation of organic pollutants in real time.

[0018] Compared with the prior art, the present invention has the following advantages: The microfluidic device provided by this invention is based on a "catalytic reaction—real-time detection—dynamic mechanism analysis" approach. It constructs a microfluidic device for real-time monitoring of organic pollutant degradation. The pollutant solution and persulfate (PMS) solution flow independently from the sample introduction unit to the premixing channel, where controlled contact is achieved. The reaction then takes place in the reaction chamber of the catalytic reaction microchannel. Utilizing the short diffusion distance and high interfacial area at the microchannel scale, rapid contact between persulfate, pollutants, and catalytically active sites is achieved. The catalytically active interface, persulfate adaptor material, and time-resolved analysis interface required for PMS catalytic degradation are integrated into a single platform, forming a dedicated device for advanced oxidation research of environmental organic pollutants. Simultaneously, by employing a continuous flow approach, the traditional discontinuous analysis of "sampling—transfer—offline detection" is transformed into a continuous "introduction—reaction—direct detection" chain. Since different flow rates and channel lengths correspond to different effective residence times, spatial location can be mapped to reaction time, thereby dynamically characterizing pollutant reduction and intermediate product formation-attenuation. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the microfluidic device of the present invention.

[0020] Figure 2 This is a schematic diagram of the microfluidic unit for catalytic reaction of the present invention.

[0021] Figure 3 A diagram illustrating the reaction mechanism of the microfluidic device constructed in this invention.

[0022] Figure 4 This is an in-situ characterization result of the Co-doped iron oxide-mediated PMS catalytic degradation of organic pollutants in Example 2 of the present invention. Figure 4 In the image, (a) is the infrared spectrum of pollutant degradation, (b) is the two-dimensional infrared spectrum of pollutant degradation, (c) is the synchronous spectrum of two-dimensional infrared correlation spectrum, and (d) is the asynchronous spectrum of two-dimensional infrared correlation spectrum.

[0023] Figure 5The XAFS energy dispersive spectroscopy characterization diagram of the PMS catalytic degradation of organic pollutants mediated by Co-doped iron oxide in Example 3 of the present invention is shown. Figure 5 In the figure, (a) is the Fe K-edge XAFS diagram of the catalyst, (b) is the Co K-edge XAFS diagram of the catalyst, (c) is the Fe absorption edge change diagram obtained from a, and (d) is the Co absorption edge change diagram calculated from b. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that the technical terms used in this invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0026] Current methods for degrading chlorinated hydrocarbons and polycyclic aromatic hydrocarbons often involve activating persulfates with transition metals or metal oxides. However, these approaches address "how degradation occurs," rather than "how to characterize degradation dynamics and intermediate product evolution in real-time under microscale continuous flow conditions," lacking real-time mechanistic analysis of the organic pollutant degradation process. For PMS-activated systems, batch beaker or fixed-bed reactors are commonly used to evaluate catalyst performance, employing a discontinuous "sampling-transfer-offline detection" analysis. This approach is prone to masking the true reaction pathway due to mixing hysteresis, sampling delays, sample transfer losses, and insufficient temporal resolution. Existing technologies also utilize online mass spectrometry for monitoring continuous flow catalytic reactions, but these primarily target organic synthesis or pharmaceutical intermediate conversion. They lack specific apparatus solutions for immobilizing heterogeneous catalysts in environmental catalytic systems, controlling PMS-pollutant contact at the microscale, and simultaneous temporal analysis of pollutants / intermediates.

[0027] Based on this, the present invention proposes a microfluidic device for real-time monitoring of the degradation of organic pollutants, such as... Figure 1 and Figure 2 As shown, it includes: The sample introduction unit 1 is used for the independent flow of pollutant solution and oxidant solution. The sample introduction unit is connected to a premixing channel 2, which is used to mix and contact the pollutant solution and catalyst solution. The catalytic reaction microfluidic unit 3 includes a catalytic reaction microfluidic chamber 5, which contains a catalyst for catalytic degradation of organic pollutants to form a reaction solution. The catalytic reaction microfluidic chamber 5 is connected to the premixing channel 2. A monitoring unit 4 is located on the catalytic reaction microfluidic chamber 5. After flowing through the catalytic reaction microfluidic chamber 5, the reaction solution is interleaved into the monitoring unit 4 for real-time monitoring and characterization of organic pollutant degradation.

[0028] This invention constructs a microfluidic device for real-time monitoring of organic pollutant degradation based on a "catalytic reaction-real-time detection-dynamic mechanism analysis" approach. In this device, pollutant solutions and persulfate (PMS) solutions flow independently from the sample introduction unit to a premixed channel, where controlled contact is achieved. The reaction then takes place within the catalytic reaction microchannel chamber. Utilizing the short diffusion distance and high interfacial area at the microchannel scale, rapid contact between persulfate, pollutants, and catalytically active sites is achieved. The catalytically active interface, persulfate adaptable materials, and time-resolved analysis interface required for PMS catalytic degradation are integrated into a single platform, forming a dedicated device for advanced oxidation research of environmental organic pollutants. Furthermore, by employing a continuous flow approach, the traditional discontinuous analysis of "sampling-transfer-offline detection" is transformed into a continuous "introduction-reaction-direct detection" chain. Since different flow rates and channel lengths correspond to different effective residence times, spatial location can be mapped to reaction time, thereby dynamically characterizing pollutant reduction and intermediate product formation-attenuation.

[0029] In this invention, the catalyst is loaded in the microfluidic reaction chamber 5 of the catalytic reaction by precipitation. The loading method and amount of catalyst can be adjusted according to the type and concentration of pollutants. By changing the flow rate, channel length, catalyst loading and persulfate / pollutant concentration, different reaction time windows can be constructed to achieve continuous monitoring of the evolution of parent pollutants and intermediate products.

[0030] Understandably, the catalytic reaction microfluidic reaction chamber is also equipped with a liquid outlet channel 6 for the flow of reaction liquid.

[0031] In some embodiments, the catalyst is a Co-doped iron oxide, wherein the Co doping amount is 12% to 18% of the iron oxide mass, and the Co-doped iron oxide is coated on the surface of a porous support; or loaded on a micropillar array, microbead bed, or three-dimensional porous framework; or formed into a detachable catalytic module. In this invention, the Co-doped iron oxide can be loaded in the microfluidic reaction chamber 5 of the catalytic reaction in various ways, such as coating the surface of a porous membrane / porous substrate to form an immobilized catalytic interface, or loading the Co-doped iron oxide on a micropillar array, microbead bed, or three-dimensional porous framework to form a high specific surface area reaction zone, or preparing a replaceable catalytic module to carry out parallel screening among different catalyst formulations.

[0032] In some embodiments, the monitoring unit 4 includes an infrared transparent window 4-1, an infrared light source 4-2, and an infrared detector 4-3. Monitoring holes are symmetrically arranged on opposite side walls of the catalytic reaction microchannel reaction chamber 5, and the infrared transparent window 4-1 is sealed and installed within the monitoring holes. The infrared light source 4-2 and the infrared detector 4-3 are respectively positioned at opposite ends of the axis of the monitoring holes, so that the detection beam emitted by the infrared light source 4-2 passes sequentially through one monitoring window, the interior of the microchannel reaction chamber 5, and the other monitoring window before being received by the infrared detector 4-3. In this invention, the infrared light source can employ SR-FTIR spectroscopy for real-time characterization of catalyst-mediated PMS activation degradation of organic pollutants. The material of the transparent monitoring window can be selected from calcium fluoride (CaF2), etc. Preferably, the monitoring unit can also employ a minimally sized capillary extraction structure, directly connected to a mass spectrometer, electrospray interface, micro-spectral cell, or chromatographic injection valve to improve intermediate product capture efficiency and time resolution.

[0033] In some embodiments, the sample introduction unit 1 includes a contaminant sample introduction unit 1-1 and an oxidant sample introduction unit 1-2. Both the contaminant sample introduction unit 1-1 and the oxidant sample introduction unit 1-2 are connected to a flow control unit, which is used to control and adjust the flow rates of the contaminant solution and the oxidant solution, respectively. In this invention, both the contaminant sample introduction unit and the oxidant sample introduction unit are equipped with a flow control unit. The flow control unit includes an injection pump and a controller. The controller controls the flow rate and flow of the injection pump, thereby controlling and adjusting the flow rates of the contaminant solution and the oxidant solution, and thus changing the residence time of the reaction liquid in the catalytic reaction microchannel. This allows the reaction liquid to be staggered and introduced into the monitoring unit 4 after flowing through the catalytic reaction microchannel reaction chamber 5.

[0034] In some embodiments, cover plates 5-1 are provided above and below the catalytic reaction microfluidic reaction chamber 5. In this invention, the cover plates 5-1 are fixed by screws, thereby forming a closed microfluidic channel in the catalytic reaction microfluidic reaction chamber 5. As a preferred embodiment of this invention, the material of the catalytic reaction microfluidic reaction chamber 5 can be selected from tetrafluoroethylene liner composite material to improve its tolerance to the PMS system.

[0035] In some embodiments, at least one monitoring unit 4 is provided along the length of the catalytic reaction microchannel reaction chamber 5. When multiple monitoring units 5 are provided, they are arranged at intervals along the length of the catalytic reaction microchannel reaction chamber 5 to sequentially detect the reaction liquid at different reaction time points.

[0036] In some embodiments, the oxidant is persulfate or hydrogen peroxide, and the organic pollutant is a chlorinated hydrocarbon and / or a polycyclic aromatic hydrocarbon. Preferably, the oxidant is persulfate, the chlorinated hydrocarbon can be trichloroethylene, and the polycyclic aromatic hydrocarbon can be organic pollutants such as BaP, BaA, DaA, and IcdP.

[0037] In summary, this invention provides a real-time monitoring microfluidic device suitable for the degradation of organic pollutants in iron oxide-activated PMS systems. The microscale flow channels shorten diffusion paths and improve interfacial contact efficiency, making it more suitable for rapid free radical oxidation reactions, thereby enhancing mass transfer and reaction efficiency. Coupled with an online detection interface, the microfluidic reactor can continuously track the PMS catalytic degradation process with low sample volumes, improving temporal resolution and integrating reaction and detection. This allows for real-time characterization of the degradation processes of organic pollutants such as trichloroethylene (TCE), BaP, BaA, DaA, and IcdP under continuous flow, microscale, and low sample consumption conditions, while simultaneously acquiring temporal changes in intermediate products. This reveals the catalytic degradation kinetics and reaction pathways of target organic pollutants. For pollutants such as TCE and highly toxic PAHs, micro-continuous flow operation reduces exposure risks and reagent consumption; immobilized catalysts also help reduce material loss and batch-to-batch variability. Compared to conventional beaker reactions, this invention significantly reduces mixing hysteresis and manual sampling bias, and is particularly suitable for capturing short-lived or low-steady-state intermediates.

[0038] The following specific examples will provide further explanation.

[0039] Example 1 The construction of a microfluidic device for real-time monitoring of organic pollutant degradation includes: The persulfate solution injection unit and the contaminant solution injection unit are connected to the premixing channel through injection tubes for mixing and contact. Both the persulfate solution injection unit and the contaminant solution injection unit are equipped with flow control units, which include an injection pump and a controller. The controller controls the flow rate and flow of the injection pump. The concentration of the persulfate solution is 1 mM, the concentration of the contaminant solution is 3 mg / L, and the contaminant is BaP.

[0040] A Co-doped iron oxide catalytic layer is added in situ to the inner wall of the catalytic reaction microchannel reaction chamber, wherein the Co doping amount is 15% of the mass of the iron oxide. The catalytic reaction microchannel reaction chamber is connected to a premixed channel, which flows the mixed solution into the catalytic reaction microchannel reaction chamber to catalytically degrade organic pollutants and form a reaction solution.

[0041] The catalytic reaction microchannel reaction chamber is equipped with a monitoring port and a synchrotron radiation micro-infrared (SR-FTIR) light source (wavelength range 650 cm⁻¹). -1 ~4000cm -1 The detector is located directly above the monitoring window, while the infrared detector (Mercury Cadmium Telluride detector) is located directly below the monitoring window. The reaction solution is introduced into the monitoring port in an alternating manner to monitor and characterize the degradation of organic pollutants in real time.

[0042] Figure 3 A diagram illustrating the reaction mechanism of the microfluidic device constructed for this invention. (See diagram for example.) Figure 3As shown, this method utilizes a synchrotron radiation source to construct a comprehensive system for in-situ chemical reaction mechanism research, integrating in-situ infrared detection and X-ray absorption fine structure characterization techniques. This system is used to track in real-time changes in component transformation, intermediate evolution, and catalyst active center structure during the catalytic degradation of organic pollutants. The sample introduction unit, constructed in this invention, is shown at the top, where two syringes pump in solution 1 (oxidant) and solution 2 (pollutant), respectively. The two solutions converge in a pre-mixed flow channel. This microfluidic design allows for precise control of the reaction initiation time, ensuring the accuracy of subsequent time-resolved detection. After mixing, the solutions can be introduced into either the in-situ infrared intermediate detection system on the left or the in-situ XAFS detection system on the right. Infrared spectroscopy is primarily used to detect molecular vibrations, thereby identifying chemical intermediates generated during the reaction. XAFS technology utilizes synchrotron X-rays to detect the valence state and coordination environment of specific elements (typically metal centers in catalysts). The main components of the infrared detection system include a synchrotron infrared beam, an infrared microfluidic device, and an infrared detector. The catalytic reaction microchannel reaction chamber is specifically divided into an upper frame, a lower frame, a liquid channel, an infrared window, a reaction chamber, and fixing screws. The infrared window and fixing screws are located on the upper frame, while the liquid channel and reaction chamber are located on the lower frame. The inlet and outlet channels penetrate the lower frame and connect to the reaction chamber. After the reaction liquid enters the reaction chamber through the mixing channel, it undergoes a redox reaction under the action of a catalyst, causing changes in the parent material and generating intermediates. A synchrotron infrared beam passes through the microchannel and is received by an infrared detector, revealing changes in chemical intermediates on a time-resolved scale. By observing the appearance and disappearance of absorption peaks, extremely short-lived intermediates A and B can be captured. The spectral data is converted into concentration-time curves to analyze the rate of intermediate formation and evolution. The main components of the in-situ XAFS detection system include a synchrotron X-ray beam, an in-situ reaction device, and an X-ray fluorescence detector. The catalytic reaction microchannel reaction chamber is a single unit made of polytetrafluoroethylene material. The reactant stream flows through a catalyst bed and is encapsulated using Kapton tape (polyimide, high temperature resistance and high X-ray transmittance). A synchrotron X-ray beam irradiates the catalyst, and a fluorescence detector collects the signal. By analyzing the XAFS spectra of the catalyst's metal elements, the changes in valence and coordination of the active sites during the reaction can be observed. The ultimate goal of this method is to combine two independent sets of data for analysis, constructing a pathway diagram of the pollutant reaction and the catalytic reaction through the intermediate evolution logic discovered by infrared spectroscopy. By combining the changes in the chemical state of the atomic active sites, the catalytic reaction mechanism can be inferred. Through the correspondence between the results of these two sets of data, the dynamic mechanism of the catalytic reaction can be clarified.

[0043] Example 2 Based on the microfluidic device constructed in Example 1, parallel microreaction channels were used to introduce TCE, BaP, BaA, DaA, and IcdP to study the mixed contamination system. The apparent reaction rates, key intermediate product spectra, and pathway differences of pollutants with different molecular structures under the same catalytic conditions were compared.

[0044] Figure 4 This is an in-situ characterization result of the Co-doped iron oxide-mediated PMS catalytic degradation of organic pollutants in Example 2 of the present invention. Figure 4 In the image, (a) is the infrared spectrum of pollutant degradation, (b) is the two-dimensional infrared spectrum of pollutant degradation, (c) is the synchronous spectrum of the two-dimensional infrared correlation spectrum, and (d) is the asynchronous spectrum of the two-dimensional infrared correlation spectrum. Figure 4 As shown in (a), time-resolved infrared spectroscopy was used to analyze the dynamic evolution of the BaP degradation process. As the reaction proceeded, the degradation process at 1235 cm⁻¹... -1 1368cm -1 and 1423cm -1 The characteristic peaks at 1029 cm⁻¹, attributed to the C−C (C=C) vibrations of the aromatic ring skeleton, gradually weaken, indicating that the aromatic ring structure in the BaP molecule is continuously oxidized and destroyed. Meanwhile, at 1029 cm⁻¹... -1 1094cm -1 1211cm -1 and 1644cm -1 New absorption peaks gradually appear at 1029 cm⁻¹, corresponding to oxygen-containing functional groups such as C−O, C=O, and C−OH, indicating that a significant oxidative functionalization process occurred during the reaction. Among them, 1029 cm⁻¹... -1 and 1211cm -1 The sustained increase in peak intensity further confirms the gradual formation of C−O groups, reflecting the continuous oxidative transformation of C−H sites in the BaP molecule. Figure 4 As shown in (b), the heatmap visually illustrates the changes in the weakening or strengthening of related functional groups. For example... Figure 4 As shown in (c) and (d), PMS (HSO5) was extracted from the infrared spectrum. − The groups Fe−O, Co−O, and −OH were identified and subjected to two-dimensional correlation spectral analysis. In the synchronous correlation spectrum, nine significant autocorrelation peaks appeared along the diagonal, corresponding to HSO5 groups. − Characteristic vibrational peaks such as Fe−O, Co−O, and interfacial water / hydroxyl groups were observed. The simultaneous presence of distinct positive and negative cross-peaks in the synchronous spectrum indicates a significant coupling and evolutionary behavior among PMS molecules, metal-oxygen coordination structures, and interfacial hydroxyl species during the reaction process. Among these, the peak at 1635 cm⁻¹... -1 With 3382cm -1 The water / hydroxyl peaks at the interface change synchronously, while at 1041 cm⁻¹... -1 1102cm-1 and 1122cm -1 (HSO5) − ), 1417cm -1 and 1435cm -1 (Fe−O) and 1533cm -1 and 1559cm -1 Characteristic peaks such as (Co−O) also showed a significant synergistic response. Further analysis using asynchronous spectroscopy revealed that, after introducing PMS into the 15% Co-Fe2O3 system, the response order of the characteristic peaks was 3382 cm⁻¹. -1 →1417cm -1 →1102cm -1 →1533cm -1 The corresponding interfacial group change path is −OH→Fe−O→HSO5 − →Co−O. This result indicates that interfacial water / hydroxyl groups initially respond and participate in the initial adsorption of PMS, followed by structural rearrangement of Fe sites to form Fe-PMS coordination intermediates, and subsequently HSO5. − S−O bond vibration changes occur, ultimately involving the Co site in the regulation of electronic structure and coordination environment. These results dynamically reveal the interfacial reaction mechanism between the catalyst active center and PMS in the catalytic reaction, providing valuable insights for a deeper understanding of PMS activation.

[0045] Example 3 Based on the microfluidic device constructed in Example 1, the degradation kinetics and intermediate distribution at different catalytic interfaces were compared by changing the Co doping ratio, iron oxide crystal phase, catalyst layer surface roughness, or loading method, establishing the correlation between "catalytic structure—ROS generation—intermediate evolution". Real-time reaction of iron oxide valence state changes in the catalyst was conducted using synchrotron XAFS.

[0046] Figure 5 The XAFS energy dispersive spectroscopy characterization diagram of the PMS catalytic degradation of organic pollutants mediated by Co-doped iron oxide in Example 3 of the present invention is shown. Figure 5 In the diagram, (a) is the Fe K-edge XAFS plot of the catalyst, (b) is the Co K-edge XAFS plot of the catalyst, (c) is the Fe absorption edge variation plot obtained from (a), and (d) is the Co absorption edge variation plot calculated from (b). Figure 5 As shown, the dynamic evolution of the chemical states of Fe and Co during the activation of 15% Co-Fe2O3 in PMS was monitored in situ using synchrotron XAFS. Analysis of Fe... K Edge and Co KThe absorption edge energy (E0) of the XANES spectrum was analyzed, and the change of ΔE0 with reaction time was compared to further reveal the dynamic transformation characteristics of the valence states of Fe and Co sites during the reaction. Compared with the unused catalyst, the E0 of Fe continuously shifted towards lower energies during the redox cycle, with ΔE0 eventually reaching approximately −0.15 eV, indicating that Fe sites continuously enriched electrons and exhibited an overall reduction trend. In contrast, the E0 of Co significantly shifted towards higher energies, with ΔE0 increasing to approximately +0.65 eV at its highest point, while the intensity of the white line peak gradually decreased, indicating a decrease in the electron density of Co sites and gradual oxidation during the reaction. These results suggest that Fe and Co play different roles in the catalyst, and this reverse cooperative valence state evolution behavior between Fe and Co indicates the existence of a directional electron transfer pathway within the system.

[0047] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0048] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A microfluidic device for real-time monitoring of the degradation of organic pollutants, characterized in that, include: The injection unit (1) is used for the independent flow of organic pollutant solution and oxidant solution. The injection unit (1) is connected to the premixing channel (2), which is used to mix and contact the pollutant solution and oxidant solution. The catalytic reaction microfluidic unit (3) includes a catalytic reaction microfluidic reaction chamber (5), which is equipped with a catalyst for catalytic degradation of organic pollutants to form a reaction solution. The catalytic reaction microfluidic reaction chamber (5) and the premixed channel (2) are connected. The monitoring unit (4) is located on the catalytic reaction microchannel reaction chamber (5). After the reaction liquid flows through the catalytic reaction microchannel reaction chamber (5), it is introduced into the monitoring unit (4) in an alternating manner to monitor and characterize the degradation of organic pollutants in real time.

2. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, The catalyst is a Co-doped iron oxide, which is coated on the surface of a porous support to form an immobilized catalytic interface; or loaded on a micropillar array, microbead bed or three-dimensional porous framework; or formed into a detachable catalytic module.

3. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, The monitoring unit (4) includes an infrared light-transmitting window (4-1), an infrared light source (4-2), and an infrared detector (4-3). Monitoring holes are symmetrically provided on the opposite side walls of the catalytic reaction microchannel reaction chamber (5). The infrared light-transmitting window (4-1) is located inside the monitoring hole. The infrared light source (4-2) and the infrared detector (4-3) are respectively located at both ends of the axis of the monitoring hole. The detection beam emitted by the infrared light source (4-2) passes through one monitoring window, the inside of the microchannel reaction chamber (5), and the other monitoring window in sequence, and is received by the infrared detector (4-3).

4. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, The injection unit (1) includes an organic pollutant injection unit (1-1) and an oxidant injection unit (1-2). Both the organic pollutant injection unit (1-1) and the oxidant injection unit (1-2) are connected to a flow control unit, which is used to control and adjust the flow rate of the pollutant solution and the oxidant solution, respectively.

5. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, The injection unit (1) is connected to a flow control unit, which is used to control and adjust the flow rate of the organic pollutant solution and the oxidant solution.

6. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, The catalytic reaction microfluidic reaction chamber (5) is equipped with cover plates (5-1) at both the top and bottom.

7. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, A monitoring unit (4) with at least one position is provided along the length direction of the catalytic reaction microchannel reaction chamber (5).

8. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 7, characterized in that, When multiple monitoring units (4) are provided, they are arranged at intervals along the length of the catalytic reaction microchannel reaction chamber (5) to sequentially detect the reaction liquid at different reaction time points.

9. The microfluidic device for real-time monitoring of organic pollutant degradation according to claim 1, characterized in that, The oxidant is persulfate or hydrogen peroxide, and the organic pollutants are chlorinated hydrocarbons and / or polycyclic aromatic hydrocarbons.

10. A method for real-time monitoring of the degradation of organic pollutants, characterized in that, Using the microfluidic device according to any one of claims 1 to 9, the process includes the following steps: The organic pollutant solution and the oxidant solution are introduced separately through the injection unit (1). The organic pollutant solution and the oxidant solution are mixed and contacted through the premixed channel (2), and then flow into the catalytic reaction microchannel reaction chamber (5) to catalytically degrade the organic pollutants and form a reaction solution. The reaction solution is introduced into the monitoring unit (4) in an alternating manner to monitor and characterize the degradation of organic pollutants in real time.

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