Microfluidic-EICP combined dynamic visual monitoring system and method for remediation process of heavy metal polluted soil

Abstract

The invention discloses a microfluidic-EICP combined dynamic visual monitoring system and method for a heavy metal polluted soil remediation process, and relates to the technical field of soil monitoring. The microfluidic-EICP combined heavy metal polluted soil remediation process dynamic visual monitoring system comprises a microfluidic reaction module, a multi-mode sensing module, a dynamic imaging module and a data analysis module, and the microfluidic reaction module comprises a heavy metal pollution simulation unit and an in-situ reaction control unit. The multi-mode sensing module comprises a substrate layer, a chemical sensing layer and a data interface layer, the dynamic imaging module comprises an optical imaging unit and a spectral analysis unit, and the data analysis module is electrically connected with the communication module. According to the technical scheme provided by the invention, multi-physical field cooperative monitoring of a chemical field, a mechanical field and a permeation field in the prior art is realized, and the cross-scale correlation analysis capability of a micro crystal growth mechanism and a macroscopic soil body modification effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of soil monitoring, and in particular to a microfluidics-EICP combined dynamic visualization monitoring system and method for the remediation process of heavy metal contaminated soil. Background Art

[0002] In recent years, the field of soil heavy metal pollution remediation technology has shown a transition trend from macro-engineering treatment to micro-mechanism regulation. Enzyme-induced carbonate precipitation (EICP) technology has become a research hotspot in this field due to its strong environmental compatibility and flexible operation. Microfluidics technology, as the core means of microscale fluid control, has demonstrated the advantages of high-precision dynamic observation in biomedical testing and environmental monitoring. However, the existing technology system still has significant bottlenecks: in the study of EICP remediation processes, conventional methods rely on endpoint sampling combined with offline analysis (such as scanning electron microscopy and X-ray diffraction), which makes it impossible for researchers to capture the transient dynamics of the coupling effect of heavy metal ion migration and carbonate precipitation; although traditional microfluidic devices can simulate microscopic flow field characteristics, their designs generally lack deep adaptability to soil remediation processes, and it is difficult to achieve multi-physics field coordinated monitoring of chemical fields, mechanical fields and infiltration fields. The ability to analyze the cross-scale correlation between microscopic crystal growth mechanisms and macroscopic soil modification effects is insufficient, resulting in technical barriers to the transformation of laboratory research results into engineering practice. Summary of the Invention

[0003] The main purpose of the present invention is to propose a dynamic visualization monitoring system and method for the remediation process of heavy metal contaminated soil combined with microfluidics and EICP, aiming to solve the problem of realizing multi-physical field coordinated monitoring of chemical field, mechanical field and infiltration field in the existing technology, and to enhance the cross-scale correlation analysis capability of the microscopic crystal growth mechanism and the macroscopic soil modification effect.

[0004] To achieve the above objectives, the present invention proposes a dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination, comprising:

[0005] The microfluidic reaction module includes a heavy metal pollution simulation unit and an in-situ reaction control unit. The heavy metal pollution simulation unit is provided with a multi-stage microchannel. The in-situ reaction control unit includes a micropump device and a temperature control device. The micropump device is used to control the flow rate of the reaction solution, and the temperature control device is used to control the reaction temperature.

[0006] A multimodal sensing module comprises a substrate layer, a chemical sensing layer, and a data interface layer. The substrate layer is integrated with spaced-apart fiber Bragg grating (FBG) sensors, which are used to monitor changes in temperature and stress fields during a reaction. The chemical sensing layer comprises an ion-selective electrode array, which is bonded to the top of the multi-stage microfluidic channel and is arranged as a whole to monitor chemical concentrations during the reaction. The data interface layer comprises a printed circuit and a communication module. The fiber Bragg grating sensors and the ion-selective electrode array are electrically connected to the communication module via the printed circuit.

[0007] A dynamic imaging module, comprising an optical imaging unit and a spectral analysis unit, wherein the optical imaging unit is used to observe the nucleation and growth process of the precipitation particles, and the spectral analysis unit is used to detect the spectral characteristics of the reaction liquid; and

[0008] The data analysis module is electrically connected to the communication module to receive and analyze real-time data and generate visual images.

[0009] In one embodiment, the multi-stage microchannel includes a main channel and a branch channel, the main channel has a width of 100 to 300 μm, and the branch channel has a width of 20 to 90 μm; and / or,

[0010] The porosity of the multi-stage microchannel is 38% to 42%; and / or,

[0011] The tortuosity of the multi-stage microchannel is 1.8 to 2.3; and / or,

[0012] The multi-stage micro-channels are distributed in a serpentine shape.

[0013] In one embodiment, the microfluidic reaction module further comprises:

[0014] The anti-clogging output unit includes a multi-stage filtering structure and a backwashing pipeline. The aperture of the multi-stage filtering structure decreases sequentially, and the backwashing pipeline is connected to the multi-stage microchannel.

[0015] In one embodiment, the anti-clogging unit is provided with a nitrogen backwashing device and a reversing valve. The nitrogen backwashing device is used to achieve backwashing by nitrogen injection. The backwashing pipeline is connected in parallel with the multi-stage microchannel through the reversing valve.

[0016] In one embodiment, the substrate layer comprises borosilicate glass with a thickness of 0.5 to 1.5 mm; and / or,

[0017] The ion selective electrode array includes Pb 2 + electrode, Cd 2 + electrode and combination pH electrode; and / or,

[0018] The multimodal sensing module further includes a fiber demodulator, which is used to analyze the signal of the fiber grating sensor and output it to the printed circuit; and / or,

[0019] The multimodal sensing module further includes a signal conditioning circuit, the ion selective electrode array is electrically connected to the printed circuit via the signal conditioning circuit, and the signal conditioning circuit is used to amplify electrode signals; and / or,

[0020] The printed circuit includes a flexible printed circuit.

[0021] In one embodiment, a flow channel observation window is further provided on the side of the microfluidic reaction module;

[0022] The optical imaging unit includes a microscope and a camera, wherein the microscope is arranged opposite to the flow channel observation window for high-magnification observation of microstructures, and the camera is arranged opposite to the microscope for capturing and recording images; and / or,

[0023] The spectrum analysis unit includes a fluorescence spectrometer and a Raman spectrometer, which are arranged on the side of the flow channel observation window. The fluorescence spectrometer is used to detect fluorescence signals, and the Raman spectrometer is used to detect molecular vibration information.

[0024] The present invention proposes a method for dynamic visualization monitoring of the remediation process of heavy metal contaminated soil using a microfluidic-EICP combination, including a dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidic-EICP combination. The dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidic-EICP combination includes:

[0025] The microfluidic reaction module includes a heavy metal pollution simulation unit and an in-situ reaction control unit. The heavy metal pollution simulation unit is provided with a multi-stage microchannel. The in-situ reaction control unit includes a micropump device and a temperature control device. The micropump device is used to control the flow rate of the reaction solution, and the temperature control device is used to control the reaction temperature.

[0026] A multimodal sensing module comprises a substrate layer, a chemical sensing layer, and a data interface layer. The substrate layer is integrated with spaced-apart fiber Bragg grating (FBG) sensors, which are used to monitor changes in temperature and stress fields during a reaction. The chemical sensing layer comprises an ion-selective electrode array, which is bonded to the top of the multi-stage microfluidic channel and is arranged as a whole to monitor chemical concentrations during the reaction. The data interface layer comprises a printed circuit and a communication module. The fiber Bragg grating sensors and the ion-selective electrode array are electrically connected to the communication module via the printed circuit.

[0027] A dynamic imaging module, comprising an optical imaging unit and a spectral analysis unit, wherein the optical imaging unit is used to observe the nucleation and growth process of the precipitation particles, and the spectral analysis unit is used to detect the spectral characteristics of the reaction liquid; and

[0028] a data analysis module, electrically connected to the communication module, to receive and analyze real-time data and generate visual images;

[0029] The dynamic visualization monitoring method for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination also includes at least the following steps:

[0030] The microfluidic reaction module is subjected to surface activation treatment to form a urease immobilization interface;

[0031] The heavy metal contaminated soil sample was mixed with the immobilized urease solution and then injected into the microfluidic reaction module;

[0032] The heavy metal contaminated solution, the background electrolyte solution and the urea-calcium source mixed solution are sequentially added;

[0033] Detecting physical and chemical properties through the multimodal sensing module and transmitting the signals to the data analysis module;

[0034] Output visualization images through the data analysis module.

[0035] In one embodiment, the step of performing surface activation treatment on the microfluidic reaction module to form a urease immobilization interface specifically includes:

[0036] Cleaning the channel surface of the multi-stage microfluidic channel using an oxygen plasma cleaning machine;

[0037] An aminosilanization reagent is used to modify the channel surface of the multi-stage microchannel to form a stable urease immobilization interface.

[0038] In one embodiment, the urea-calcium source mixed solution is pulsed perfused; and / or,

[0039] The background electrolyte solution includes Pb2 + solution, Cd2 + solution and NaCl solution, Pb2 + The concentration is 500~1500mg / L, Cd2 + The concentration is 100-300 mg / L, the NaCl solution is 0.05-0.15; and / or,

[0040] The urea-calcium source mixed solution includes a urea solution and a CaCl2 solution, wherein the urea concentration gradient is 0.8-1.5M, and the CaCl2 concentration is 0.5-1.2M.

[0041] In one embodiment, after the step of outputting the visual image through the data analysis module, the method further includes:

[0042] Reverse perfusion of deionized water to remove free precipitates;

[0043] Injecting chelating solution to chelate residual heavy metal ions;

[0044] Purge with nitrogen to dry the flow channel.

[0045] In the technical solution of the present invention, a multi-stage microfluidic channel is installed within the metal contamination simulation unit to simulate the complex flow paths of heavy metals in soil, providing conditions close to real-world conditions for subsequent remediation reactions. A micropump device precisely controls the flow rate of the reaction solution, thereby regulating the reaction rate. A temperature control device controls the reaction temperature. Because temperature has a significant impact on the rate and direction of chemical reactions, a suitable temperature helps improve remediation efficiency and effectiveness. By integrating fiber grating (FBG) sensors at intervals within the substrate layer and leveraging their sensitivity to temperature and stress, changes in the temperature and stress fields during the reaction are monitored in real time. These changes in physical fields can reflect the progress and status of the reaction. The ion-selective electrode array in the chemical sensing layer is bonded to the top of the multi-stage microfluidic channel to monitor the concentration of specific ions, such as heavy metal ions. By monitoring chemical concentration changes in real time, the transformation of substances during the remediation reaction can be understood. Data collected by the fiber grating sensors and ion-selective electrode array is transmitted via a printed circuit and communication module, ensuring accurate and stable data transmission to the data analysis module. The nucleation and growth process of the precipitated particles is observed through the optical equipment in the optical imaging unit. The formation and growth of the precipitated particles are closely related to the fixation and removal of heavy metals, and this observation allows for an intuitive understanding of the microscopic process of the reaction. The spectral analysis unit detects the spectral characteristics of the reaction solution. The spectral information can reflect information such as the molecular structure and chemical bonds of the substances in the reaction solution, which helps to deeply analyze the chemical mechanism of the reaction. The data analysis module receives real-time data from the communication module, processes and analyzes the data using data analysis algorithms, and ultimately generates visual images, allowing researchers to intuitively observe and interpret the dynamic changes in the remediation process. In this way, the system can obtain real-time data on temperature, stress, chemical concentration, precipitated particle growth, and reaction solution spectrum during the reaction process. This solves the existing problem of achieving multi-physics coordinated monitoring of chemical fields, mechanical fields, and infiltration fields, and enhances the cross-scale correlation and analysis capabilities of the microscopic crystal growth mechanism and the macroscopic soil modification effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0047] Figure 1 This is a graph showing the change in lead leaching concentration over time in Example 1;

[0048] Figure 2 This is a graph showing the growth of carbonate precipitation coverage in Example 1;

[0049] Figure 3 This is a comparison chart of the improvement of soil mechanical properties in Example 1;

[0050] Figure 4 This is the evolution diagram of the pore structure parameters of Example 1;

[0051] Figure 5 This is a graph showing the change in Cd removal rate at different temperatures in Example 2;

[0052] Figure 6 This is a graph showing the change in Cd removal rate at different flow rates in Example 2;

[0053] Figure 7A This is a graph of precipitation coverage at different temperatures in Example 3;

[0054] Figure 7B This is a graph of sedimentation coverage at different flow rates in Example 3.

[0055] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0057] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0058] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes, taking "A and / or B" as an example, but it must be based on the ability of ordinary technicians in this field to implement it, when the technical scheme includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical schemes between the various embodiments can be combined with each other. When the combination is contradictory or cannot be implemented, it should be deemed that such a combination of technical schemes does not exist and is not within the scope of protection required by the present invention.

[0059] In recent years, the field of soil heavy metal pollution remediation technology has shown a transition trend from macro-engineering treatment to micro-mechanism regulation. Enzyme-induced carbonate precipitation (EICP) technology has become a research hotspot in this field due to its strong environmental compatibility and flexible operation. Microfluidics technology, as the core means of microscale fluid control, has demonstrated the advantages of high-precision dynamic observation in biomedical testing and environmental monitoring. However, the existing technology system still has significant bottlenecks: in the study of EICP remediation processes, conventional methods rely on endpoint sampling combined with offline analysis (such as scanning electron microscopy and X-ray diffraction), which makes it impossible for researchers to capture the transient dynamics of the coupling effect of heavy metal ion migration and carbonate precipitation; although traditional microfluidic devices can simulate microscopic flow field characteristics, their designs generally lack deep adaptability to soil remediation processes, and it is difficult to achieve multi-physics field coordinated monitoring of chemical fields, mechanical fields and infiltration fields. The ability to analyze the cross-scale correlation between microscopic crystal growth mechanisms and macroscopic soil modification effects is insufficient, resulting in technical barriers to the transformation of laboratory research results into engineering practice.

[0060] In order to solve the above technical problems, the present invention proposes a dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination, comprising:

[0061] The microfluidic reaction module includes a heavy metal pollution simulation unit and an in-situ reaction control unit. The heavy metal pollution simulation unit is provided with a multi-stage microchannel. The in-situ reaction control unit includes a micropump device and a temperature control device. The micropump device is used to control the flow rate of the reaction solution, and the temperature control device is used to control the reaction temperature.

[0062] A multimodal sensing module comprises a substrate layer, a chemical sensing layer, and a data interface layer. The substrate layer is integrated with spaced-apart fiber Bragg grating (FBG) sensors, which are used to monitor changes in temperature and stress fields during a reaction. The chemical sensing layer comprises an ion-selective electrode array, which is bonded to the top of the multi-stage microfluidic channel and is arranged as a whole to monitor chemical concentrations during the reaction. The data interface layer comprises a printed circuit and a communication module. The fiber Bragg grating sensors and the ion-selective electrode array are electrically connected to the communication module via the printed circuit.

[0063] A dynamic imaging module, comprising an optical imaging unit and a spectral analysis unit, wherein the optical imaging unit is used to observe the nucleation and growth process of the precipitation particles, and the spectral analysis unit is used to detect the spectral characteristics of the reaction liquid; and

[0064] The data analysis module is electrically connected to the communication module to receive and analyze real-time data and generate visual images.

[0065] In the technical solution of the present invention, a multi-stage microfluidic channel is installed within the metal contamination simulation unit to simulate the complex flow paths of heavy metals in soil, providing conditions close to real-world conditions for subsequent remediation reactions. A micropump device precisely controls the flow rate of the reaction solution, thereby regulating the reaction rate. A temperature control device controls the reaction temperature. Because temperature has a significant impact on the rate and direction of chemical reactions, a suitable temperature helps improve remediation efficiency and effectiveness. By integrating fiber grating (FBG) sensors at intervals within the substrate layer and leveraging their sensitivity to temperature and stress, changes in the temperature and stress fields during the reaction are monitored in real time. These changes in physical fields can reflect the progress and status of the reaction. The ion-selective electrode array in the chemical sensing layer is bonded to the top of the multi-stage microfluidic channel to monitor the concentration of specific ions, such as heavy metal ions. By monitoring chemical concentration changes in real time, the transformation of substances during the remediation reaction can be understood. Data collected by the fiber grating sensors and ion-selective electrode array is transmitted via a printed circuit and communication module, ensuring accurate and stable data transmission to the data analysis module. The nucleation and growth process of the precipitated particles is observed through the optical equipment in the optical imaging unit. The formation and growth of the precipitated particles are closely related to the fixation and removal of heavy metals, and this observation allows for an intuitive understanding of the microscopic process of the reaction. The spectral analysis unit detects the spectral characteristics of the reaction solution. The spectral information can reflect information such as the molecular structure and chemical bonds of the substances in the reaction solution, which helps to deeply analyze the chemical mechanism of the reaction. The data analysis module receives real-time data from the communication module, processes and analyzes the data using data analysis algorithms, and ultimately generates visual images, allowing researchers to intuitively observe and interpret the dynamic changes in the remediation process. In this way, the system can obtain real-time data on temperature, stress, chemical concentration, precipitated particle growth, and reaction solution spectrum during the reaction process. This solves the existing problem of achieving multi-physics coordinated monitoring of chemical fields, mechanical fields, and infiltration fields, and enhances the cross-scale correlation and analysis capabilities of the microscopic crystal growth mechanism and the macroscopic soil modification effect.

[0066] In one embodiment, the multi-stage microfluidic channel includes a main channel and branch channels, with the main channel width ranging from 100 to 300 μm and the branch channel width ranging from 20 to 90 μm. This configuration, by providing main and branch channels of varying widths, can more accurately simulate the complex flow paths of heavy metals in soil, making the remediation reactions performed in the microfluidic reaction module more realistic, improving the authenticity and reliability of experimental results and providing more valuable data for subsequent research and applications.

[0067] In one embodiment, the porosity of the multi-stage microchannel is 38% to 42%. Setting this range ensures that the reaction liquid can penetrate smoothly through the multi-stage microchannel. When the porosity is between 38% and 42%, the reaction liquid can pass through the microchannel more smoothly, fully contacting the heavy metal-contaminated soil and promoting the remediation reaction. If the porosity is too low, the permeation resistance of the reaction liquid will increase, making it difficult for the reaction liquid to reach various parts of the microchannel, affecting the remediation effect; conversely, if the porosity is too high, the reaction liquid may flow too fast, resulting in insufficient reaction time, which is also not conducive to the full progress of the remediation reaction.

[0068] In one embodiment, the tortuosity of the multi-stage microfluidic channel is 1.8 to 2.3. This configuration extends the fluid residence time by maintaining a tortuosity within this range: the appropriate tortuosity can lengthen the flow path of the reaction liquid within the multi-stage microfluidic channel, thereby extending the contact time between the reaction liquid and the heavy metal-contaminated soil. This helps the remediation agent in the reaction liquid react more fully with the heavy metal ions, improving the removal efficiency of heavy metals. If the tortuosity is too small, the reaction liquid may pass through the microfluidic channel too quickly, resulting in an incomplete reaction; while if the tortuosity is too large, the fluid flow resistance may be too large, affecting the transport of the reaction liquid.

[0069] In one embodiment, the multi-stage microchannels are arranged in a serpentine pattern. This arrangement allows the microchannels to extend longer within a given plane space. This significantly increases the contact area between the reaction solution and the heavy metal-contaminated soil, allowing the remediation agent in the reaction solution more opportunities to react with the heavy metal ions, thereby improving the efficiency and effectiveness of the remediation reaction. Compared to linear or simple channel layouts, a serpentine pattern allows for a more complete and comprehensive reaction.

[0070] In one embodiment, the microfluidic reaction module further includes: a blockage output unit, the anti-blockage output unit includes a multi-stage filtration structure and a backwash pipeline, the pore size of the multi-stage filtration structure decreases successively, and the backwash pipeline is connected to the multi-stage microchannel. With such an arrangement, the impurities in the fluid can be gradually intercepted from large to small through the design of the multi-stage filtration structure with a decreasing pore size. Larger impurities will be intercepted by the filter layer with a larger pore size, and as the fluid continues to flow, smaller impurities will be blocked by the subsequent filter layer with a smaller pore size. This can prevent impurities from accumulating in the microchannel, reduce the risk of blockage, ensure that the reaction liquid can flow smoothly in the microchannel, and maintain the normal progress of the reaction.

[0071] In one embodiment, the anti-clogging unit is provided with a nitrogen back-flushing device and a reversing valve, wherein the nitrogen back-flushing device is used to achieve back-flushing by nitrogen injection, and the back-flushing pipe is connected in parallel with the multi-stage microchannel via the reversing valve. In this manner, the nitrogen back-flushing device is used to perform back-flushing by nitrogen injection, and nitrogen has the advantages of being chemically stable and not easily reacting with the reaction liquid and substances in the microchannel. During back-flushing, the high-speed flowing nitrogen can generate a strong impact force, effectively removing impurities, sediments and other blockages accumulated in the multi-stage microchannel. Compared with other flushing media, nitrogen does not introduce additional pollutants, thereby ensuring the cleanliness of the microchannel and the stability of the reaction environment. In addition, the back-flushing pipe is connected in parallel with the multi-stage microchannel through the setting of the reversing valve, which enables the flushing process to be flexibly controlled. Under normal operating conditions, the reversing valve allows the reaction solution to flow smoothly through the multi-stage microfluidic channel. If a blockage is detected or scheduled maintenance is required, the reversing valve can be operated to connect the nitrogen backflush device to the multi-stage microfluidic channel, enabling reverse flushing. This flexible control method allows for timely flushing operations based on actual conditions, preventing further clogging and ensuring the continuous and stable operation of the microfluidic reaction module.

[0072] In one embodiment, the substrate layer comprises borosilicate glass with a thickness of 0.5-1.5 mm. This configuration provides excellent optical transparency. The 0.5-1.5 mm thickness ensures light transmittance while reducing light scattering and absorption within the glass. This is crucial for microfluidic chips requiring optical detection (such as fluorescence and colorimetric detection), enabling accurate transmission and reception of detection signals, improving detection sensitivity and accuracy.

[0073] In one embodiment, the ion selective electrode array comprises Pb 2 + electrode, Cd 2 + electrode and composite pH electrode; compared with using individual electrodes for multiple measurements, integrating these electrodes into one array can significantly reduce testing time and workload. It can complete the detection of multiple parameters at one time.

[0074] In one embodiment, the multimodal sensing module further includes a fiber demodulator, which is used to analyze the signal of the fiber Bragg grating sensor and output it to the printed circuit. In this way, the fiber Bragg grating sensor is a sensing element based on fiber Bragg grating, which can change the characteristics of its reflected or transmitted light according to changes in external physical quantities (such as temperature, strain, etc.). However, these optical signals need to be professionally processed before they can be converted into electrical signals or digital signals that can be identified and analyzed. The fiber demodulator has the ability to accurately analyze these complex optical signals and can accurately extract information related to external physical quantities.

[0075] In one embodiment, the multimodal sensing module further includes a signal conditioning circuit, and the ion selective electrode array is electrically connected to the printed circuit via the signal conditioning circuit, and the signal conditioning circuit is used to amplify the electrode signal. With such a configuration, the signal output by the ion selective electrode array is usually relatively weak, and is easily interfered by external noise during transmission and processing, and may even be drowned by the noise and difficult to accurately detect. The signal conditioning circuit can amplify these weak electrode signals to a suitable intensity, so that the subsequent printed circuit can further process and analyze the signal. For example, when detecting trace heavy metal ions, the initial signal generated by the electrode is extremely weak. After amplification by the signal conditioning circuit, the amplitude of the signal is significantly improved, providing a basis for accurate measurement.

[0076] In one embodiment, the printed circuit comprises a flexible printed circuit, which has better durability and reliability in complex use environments because the flexible printed circuit can withstand a certain degree of bending, torsion and vibration.

[0077] In one embodiment, a flow channel observation window is further provided on the side of the microfluidic reaction module; the optical imaging unit includes a microscope and a camera, the microscope being positioned directly opposite the flow channel observation window for high-magnification observation of microstructures, and the camera being positioned directly opposite the microscope for capturing and recording images. This arrangement provides a direct window for observing the flow channel conditions within the microfluidic reaction module through the flow channel observation window. Through this window, combined with the high-magnification function of the microscope, microscopic details such as the flow state of the fluid in the microchannel, the motion trajectory of the particles, and the progress of the chemical reaction can be clearly seen.

[0078] In one embodiment, the spectral analysis unit includes a fluorescence spectrometer and a Raman spectrometer, which are arranged on the side of the flow channel observation window. The fluorescence spectrometer is used to detect fluorescence signals, and the Raman spectrometer is used to detect molecular vibration information. With this arrangement, the fluorescence spectrometer and the Raman spectrometer detect substances in the flow channel of the microfluidic reaction module from different angles. By detecting fluorescence signals, the fluorescence spectrometer can specifically detect substances with fluorescent properties. By obtaining molecular vibration information, the Raman spectrometer can provide detailed information on molecular structure and chemical bonds, and perform fingerprint identification on the substance. Different molecules have unique Raman spectral characteristics, which can be used to identify various chemical components.

[0079] The present invention proposes a method for dynamic visualization monitoring of the remediation process of heavy metal contaminated soil using a microfluidic-EICP combination, including a dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidic-EICP combination. The dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidic-EICP combination includes:

[0080] The microfluidic reaction module includes a heavy metal pollution simulation unit and an in-situ reaction control unit. The heavy metal pollution simulation unit is provided with a multi-stage microchannel. The in-situ reaction control unit includes a micropump device and a temperature control device. The micropump device is used to control the flow rate of the reaction solution, and the temperature control device is used to control the reaction temperature.

[0081] A multimodal sensing module comprises a substrate layer, a chemical sensing layer, and a data interface layer. The substrate layer is integrated with spaced-apart fiber Bragg grating (FBG) sensors, which are used to monitor changes in temperature and stress fields during a reaction. The chemical sensing layer comprises an ion-selective electrode array, which is bonded to the top of the multi-stage microfluidic channel and is arranged as a whole to monitor chemical concentrations during the reaction. The data interface layer comprises a printed circuit and a communication module. The fiber Bragg grating sensors and the ion-selective electrode array are electrically connected to the communication module via the printed circuit.

[0082] A dynamic imaging module, comprising an optical imaging unit and a spectral analysis unit, wherein the optical imaging unit is used to observe the nucleation and growth process of the precipitation particles, and the spectral analysis unit is used to detect the spectral characteristics of the reaction liquid; and

[0083] a data analysis module, electrically connected to the communication module, to receive and analyze real-time data and generate visual images;

[0084] The dynamic visualization monitoring method for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination also includes at least the following steps:

[0085] The microfluidic reaction module is subjected to surface activation treatment to form a urease immobilization interface;

[0086] The heavy metal contaminated soil sample was mixed with the immobilized urease solution and then injected into the microfluidic reaction module;

[0087] The heavy metal contaminated solution, the background electrolyte solution and the urea-calcium source mixed solution are sequentially added;

[0088] Detecting physical and chemical properties through the multimodal sensing module and transmitting the signals to the data analysis module;

[0089] Output visualization images through the data analysis module.

[0090] In the technical solution of the present invention, a microfluidic reaction module is surface activated to form a urease immobilization interface. The flow channel surface of the multi-stage microchannel can be cleaned using an oxygen plasma cleaner and then modified with an aminosilanization reagent to form a stable urease immobilization interface. This helps the urease better adhere to the module surface, maintain its activity and stability, and provide an efficient catalytic environment for subsequent heavy metal pollution remediation reactions. Mixing a heavy metal-contaminated soil sample with an immobilized urease solution and then injecting it into the microfluidic reaction module can make the reaction more realistic in soil pollution scenarios. The heavy metal contaminated solution, background electrolyte solution, and urea-calcium source mixed solution are then injected sequentially to gradually build a complete reaction system, providing a suitable material basis and chemical environment for subsequent remediation reactions. The multimodal sensing module integrates multiple sensors, such as fiber grating sensors to monitor temperature and stress field changes, and ion-selective electrode arrays to monitor chemical concentrations. These sensors can detect various physical and chemical properties during the reaction process in real time and comprehensively, providing rich data support for a deeper understanding of the progress and mechanism of the remediation reaction. The multimodal sensing module transmits detected signals to the data analysis module via the printed circuit and communication module of the data interface layer, ensuring accurate and stable data transmission and the reliability of subsequent data analysis. The data analysis module receives real-time data from the communication module, processes and analyzes the data using data analysis algorithms, and ultimately generates visual images. These visual images can intuitively demonstrate various dynamic changes during the repair process, such as temperature distribution, changes in ion concentration, and precipitation particle growth. This allows researchers to quickly and accurately observe and interpret the reaction process, identify problems promptly, and adjust experimental parameters, thereby improving research efficiency and accuracy.

[0091] It is understandable that the data analysis module builds an intelligent analysis platform based on a cloud-edge-end collaborative architecture, supporting three-dimensional data visualization. The data end uses a timestamp alignment algorithm to perform spatiotemporal registration of sensor data, microscopic images, and Raman spectra. Sensor data includes chemical concentration and temperature, microscopic images are used to analyze precipitation coverage, and Raman spectra are used to calculate the proportion of crystal forms, ultimately generating a five-dimensional feature matrix containing time, spatial coordinates, chemical parameters, physical parameters, and mineral phases. In terms of modeling, the U-Net deep learning model is used to achieve precipitation particle segmentation in scanning electron microscope (SEM) images. The model uses ResNet34 as the backbone network, and the Dice coefficient of the segmentation result is higher than 0.92. At the same time, the long short-term memory network (LSTM) is combined to predict the heavy metal fixation efficiency, with a mean absolute percentage error (MAPE) of less than 8%. The data visualization part reconstructs the pore network model based on high-resolution μ-CT scanning data, and uses the ParaView engine to render the correlation cloud map of permeability and porosity, supporting multi-dimensional interactive analysis.

[0092] In one embodiment, the step of surface activation of the microfluidic reaction module to form a urease immobilization interface specifically includes: cleaning the channel surface of the multi-stage microfluidic channel using an oxygen plasma cleaner; and modifying the channel surface of the multi-stage microfluidic channel using an aminosilanization reagent to form a stable urease immobilization interface. This configuration allows the oxygen plasma cleaner to generate high-energy plasma. The active particles in this plasma can react with organic pollutants and microparticles on the channel surface of the multi-stage microfluidic channel, decomposing them into gaseous substances and removing them. This process penetrates deeply into the microstructure of the channel, ensuring extremely high cleanliness of the channel surface, providing a pure foundation for subsequent modification and urease immobilization. The plasma also breaks molecular bonds on the channel surface, generating a large number of free radicals and unsaturated bonds, thereby significantly increasing the surface's chemical activity. This highly active surface is more susceptible to chemical reactions with the aminosilanization reagent, facilitating the smooth progress of subsequent modification steps. The silane groups in the aminosilanization reagent can react with groups such as hydroxyl groups on the surface of the cleaned and activated flow channel to form stable covalent bonds, thereby firmly adhering to the flow channel surface. At the same time, the amino groups in the reagent can react with specific groups (such as carboxyl groups) on the urease molecule, covalently linking the urease to the flow channel surface to form a stable urease fixed interface. Compared with physical adsorption and other methods, this covalent binding method can more effectively prevent the urease from falling off during the reaction process, ensuring that the urease continues to play a role throughout the repair process.

[0093] In one embodiment, the urea-calcium source mixed solution is pulsed. This arrangement allows for intermittent delivery of urea and the calcium source into the microchannels. During the intervals between perfusions, the previously injected solution has ample time to fully react with the heavy metal-contaminated soil, immobilized urease, and other components. This avoids the problem of incomplete reaction caused by the solution passing through the microchannel too quickly, which can occur with continuous perfusion. This allows for more complete reactions, including the hydrolysis of urea to produce carbonate ions and the combination of carbonate ions with heavy metal ions to form a precipitate. This improves the utilization efficiency of urea and the calcium source and enhances heavy metal removal.

[0094] In one embodiment, the background electrolyte solution comprises Pb2 + solution, Cd2 + solution and NaCl solution, Pb2 + The concentration is 500~1500mg / L, Cd2 + The concentration range is 100-300 mg / L, and the NaCl solution is 0.05-0.15. This setup can realistically simulate the presence and concentration range of heavy metals in a contaminated environment. This facilitates research on the remediation effects and reaction mechanisms of heavy metal-contaminated soil using microfluidics-EICP technology under conditions close to actual pollution.

[0095] In one embodiment, the urea-calcium source mixed solution includes a urea solution and a CaCl2 solution, the urea concentration gradient is 0.8 to 1.5 M, and the CaCl2 concentration is 0.5 to 1.2 M. In this way, in the microfluidics-EICP combined heavy metal contaminated soil remediation process, urea is the substrate for the urease-catalyzed reaction. Urease hydrolyzes urea into ammonia and carbon dioxide, and then generates carbonate ions. By setting a urea concentration gradient of 0.8-1.5 M, the effects of different substrate concentrations on the rate and efficiency of the urease-catalyzed reaction can be studied. A lower concentration of urea may result in a slower reaction rate, while an excessively high concentration of urea may inhibit urease. The most suitable urea concentration for the reaction can be found by setting the gradient.

[0096] In one embodiment, after outputting a visual image via the data analysis module, the process further includes: reverse perfusion of deionized water to remove free precipitates; injection of a chelating solution to chelate residual heavy metal ions; and nitrogen purging to dry the flow channel. With this arrangement, reverse perfusion of deionized water can utilize the flushing effect of the water flow to remove free precipitates from the flow channel, ensuring a clear and unobstructed flow channel.

[0097] Inject chelating solution to chelate residual heavy metal ions

[0098] Although the EICP process removes most heavy metal ions through coprecipitation, a small amount may still remain in the flow channel or adsorbed on the channel walls. The chelating solution contains a chelating agent, such as ethylenediaminetetraacetic acid (EDTA), that can form stable complexes with heavy metal ions. After the chelating solution is injected, the chelating agent reacts with the remaining heavy metal ions, desorbing them from the flow channel walls or other surfaces to form stable complexes, further reducing the heavy metal ion concentration in the flow channel and improving the repair effect. Nitrogen purging and drying the flow channel: After rinsing with deionized water and treating with the chelating solution, a certain amount of liquid will remain in the flow channel. If this liquid is not removed promptly, it may breed microorganisms, cause channel corrosion, and affect the accuracy of subsequent experiments. Nitrogen is an inert gas with stable chemical properties and is not prone to reacting with materials in the flow channel. Nitrogen purging can quickly dry out the liquid in the flow channel, restoring the channel to a dry state and preparing it for the next experiment or repair operation. This improves reuse efficiency.

[0099] The following is an example of a specific implementation method:

[0100] Example 1:

[0101] This example selects the contaminated soil around a lead-zinc mine in Jiaozuo, Henan Province as the research object, with a sampling depth of 0-20 cm. The soil was air-dried, crushed, and then sieved through a 2 mm sieve. Its basic physical and chemical properties are: total lead 850 mg / kg, TCLP leaching concentration 12.5 mg / L; total cadmium 65 mg / kg, TCLP leaching concentration 2.1 mg / L, pH 6.3, organic matter content 1.8%, clay content 28%, and porosity 42%. The experiment used urease extracted from sword beans, with an enzyme activity of 15 U / mg, and a loading capacity of 1.5 U / cm after immobilization treatment. 2 By setting different urea concentration gradients, the effect on the catalytic efficiency of urease was studied.

[0102] The microfluidic chip was fabricated using a PDMS-glass bonding process. The main channel width is 200 μm, the branch network pore diameter is 50-100 μm, and the tortuosity is 2.1, simulating the actual soil pore structure. The perfusion system is equipped with a dual-channel syringe pump (Harvard Apparatus PHD Ultra), with a flow rate accuracy of ±0.1 μL / min. The sensing module integrates a temperature sensor, a lead ion selective electrode, and a distributed fiber Bragg grating sensor. The imaging unit, consisting of a confocal microscope and a Raman spectrometer, supports dynamic observation and spectral analysis.

[0103] The experimental process begins with oxygen plasma cleaning of the PDMS chip. A 3% APTES ethanol solution is then injected and allowed to stand at 25°C for 12 hours to complete aminosilanization. The contaminated soil sample and immobilized urease solution are mixed at a mass ratio of 1:3 and injected into the chip reaction chamber at a flow rate of 2 μL / min. The mixture is then left to stand for 12 hours to complete enzyme immobilization.

[0104] The dynamic repair process is divided into two stages: pollutant migration simulation and EICP cementing fluid perfusion. The pollutant migration stage lasted for 6 hours, and a lead ion contaminated solution with a concentration of 1500 mg / L and pH = 6.0 and 0.1M background electrolyte NaCl was injected at a flow rate of 0.5μL / min. Monitoring showed that the lead ion concentration at the outlet of the flow channel reached an equilibrium value of 1250±35 mg / L, verifying the effectiveness of the diffusion simulation. It was then switched to a urea-CaCl2 mixture (concentration 1.2M urea / 0.8MCaCl2), using a pulsed perfusion mode with a pressurization cycle of 5s and a pressure of 18kPa; a pressure release cycle of 10s, which lasted for 48 hours. Multimodal data was collected synchronously: the chemical sensor recorded pH, conductivity and lead ion concentration every 10 minutes; the confocal microscope collected Z-axis stack images every 30 minutes; and the Raman spectrometer scanned 1080-1090cm every hour. -1 Characteristic peak area.

[0105] After the experiment, a three-stage cleaning procedure was performed: reverse perfusion with deionized water at 10 μL / min for 30 minutes to remove free precipitates; injection of 0.1 M EDTA solution (pH 8.0) for 60 minutes to complex adsorbed lead ions; and nitrogen purge at 50 kPa for 15 minutes to dry the flow channel. After five reuses, the chip retained 88% of its initial urease activity, verifying the system's stability and reproducibility.

[0106] Test conclusion: Figure 1 As shown in the data, the lead ion concentration in the TCLP leaching experiment dropped from 12.5 mg / L to 0.8 mg / L, which is lower than the 1.0 mg / L limit of the "Soil Environmental Quality Agricultural Land Soil Pollution Risk Control Standard" (GB15618-2018).

[0107] like Figure 2 As shown, the amount of calcium carbonate precipitation is 12.7wt%, and calcite accounts for 82%.

[0108] like Figure 3 As shown in the figure, in terms of mechanical properties, direct shear tests show that the cohesion of the soil increased from 15kPa to 48kPa after repair, the internal friction angle increased from 28° to 34°, and the unconfined compressive strength reached 650kPa, which was 3.25 times higher than before repair.

[0109] like Figure 4 As shown in Figure 3, μ-CT analysis showed that the porosity decreased from 42% to 31%, the average pore size shrank from 50 μm to 28 μm, and the precipitation coverage increased exponentially with time (R = 0.98), reaching 89 ± 3% at 48 h.

[0110] In summary, this example, through multimodal dynamic monitoring and quantitative analysis, confirms that the system can efficiently remediate lead-contaminated soil, with a lead fixation rate of 93.6%, significantly superior to the traditional stirring reaction method (approximately 75%). The monitoring data is highly accurate, with a precipitation coverage prediction error of less than 5% and a crystal form identification accuracy rate exceeding 90%. The chip has excellent anti-clogging performance and has been running continuously for 120 hours without flow channel occlusion, providing a replicable technical solution for the remediation of contaminated soil in mining areas.

[0111] Example 2:

[0112] This example aims to demonstrate the dynamic response and visual monitoring performance of the microfluidics-EICP hybrid system described herein during the remediation of cadmium (Cd)-contaminated soil. Natural air-dried medium sand was selected, sieved to a particle size of less than 2 mm, and then dried for later use. CdCl₂·2.5H₂O was dissolved in deionized water at a mass ratio of 0.2%, mixed evenly with the dry sand, and then loaded into the pre-treated microfluidic chip reaction chamber. The mixture was allowed to stand for 48 hours to achieve sufficient adsorption and stabilization.

[0113] The reaction solution was prepared as follows: urease concentration of 1.5 g / L, CaCl2 concentration of 0.5 mol / L, and pH controlled at 7.0 ± 0.2. The solution was continuously infused via a syringe pump at a constant flow rate of 1.0 μL / min for 72 hours. Fluorescent staining was used during the reaction, and the precipitation process was dynamically observed using an inverted fluorescence microscope (100× magnification) to monitor the precipitation starting location, nucleation rate, and coverage. After the experiment, soil samples were dissected from the chip, and CaCO2 content and Cd residual content were determined in different areas.

[0114] like Figure 5 As shown in the figure, the Cd removal rate reached 88% at 1.0 μL / min and 30°C, and the precipitation coverage reached Figure 7A As shown in Figure 1, the precipitation distribution gradually expanded from the inlet to the middle of the channel, with dense nucleation and uniform deposition. TCLP testing reduced the Cd leaching concentration from an initial 3.2 mg / L to 0.18 mg / L, achieving a removal efficiency of 94%. These results demonstrate that this system can achieve efficient CaCO2 precipitation induction under visual monitoring and complete pollutant stabilization under microscale conditions.

[0115] Example 3:

[0116] This example aims to explore the influence of temperature and flow rate on the repair performance of the microfluidic-EICP combined system of the present invention, and further evaluate its mechanism of action on the precipitation reaction process and heavy metal removal efficiency.

[0117] First, a temperature control experiment was conducted, maintaining constant reaction solution parameters (1.5 g / L urease, 0.5 mol / L CaCl2, pH 7.0) and setting the injection flow rate to 1.0 μL / min. The microfluidic chip was placed on a thermostat and set to seven temperature settings: 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C. The reaction time was 72 hours. Figure 5 As can be seen, the Cd removal rate gradually increased with the increase of temperature, from 52% at 10℃ to 91% at 35℃, and then slightly decreased to 89%; Figure 7A It shows that the precipitation coverage also increases from 45% to a peak of 86% at 35°C, demonstrating good temperature responsiveness.

[0118] Then, a flow rate variable test was carried out, with a fixed temperature of 30°C and an injection flow rate ranging from 0.5 μL / min to 2.1 μL / min, with an interval of 0.1 μL / min, and 17 sets of experiments were set. Figure 6 As shown, the Cd removal efficiency showed a downward trend with increasing flow rate, decreasing from a maximum of 93% at 0.5 μL / min to a minimum of 49% at 2.1 μL / min; Figure 7BThe results showed that the precipitation coverage rate also gradually decreased from a maximum of 90% to 49%. Too fast a flow rate shortened the reaction contact time, resulting in discontinuous precipitation and accumulation at the chip inlet area, affecting stability.

[0119] These results clearly demonstrate that suitable temperature and low flow rate are key to achieving uniform precipitation distribution and efficient heavy metal removal. The system of the present invention can precisely control precipitation behavior by controlling parameters, demonstrating excellent process adaptability and promising prospects for engineering expansion.

[0120] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformation made by utilizing the contents of the present invention's description and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination, characterized in that: include: The microfluidic reaction module includes a heavy metal pollution simulation unit and an in-situ reaction control unit. The heavy metal pollution simulation unit is provided with a multi-stage microchannel. The in-situ reaction control unit includes a micropump device and a temperature control device. The micropump device is used to control the flow rate of the reaction solution, and the temperature control device is used to control the reaction temperature. A multimodal sensing module comprises a substrate layer, a chemical sensing layer, and a data interface layer. The substrate layer is integrated with spaced-apart fiber Bragg grating (FBG) sensors, which are used to monitor changes in temperature and stress fields during a reaction. The chemical sensing layer comprises an ion-selective electrode array, which is bonded to the top of the multi-stage microfluidic channel and is arranged as a whole to monitor chemical concentrations during the reaction. The data interface layer comprises a printed circuit and a communication module. The fiber Bragg grating sensors and the ion-selective electrode array are electrically connected to the communication module via the printed circuit. A dynamic imaging module, comprising an optical imaging unit and a spectral analysis unit, wherein the optical imaging unit is used to observe the nucleation and growth process of the precipitation particles, and the spectral analysis unit is used to detect the spectral characteristics of the reaction liquid; and The data analysis module is electrically connected to the communication module to receive and analyze real-time data and generate visual images.

2. The microfluidics-EICP combined dynamic visualization monitoring system for heavy metal contaminated soil remediation process according to claim 1 is characterized in that: The multi-stage microchannel includes a main channel and a branch channel, the main channel has a width of 100 to 300 μm, and the branch channel has a width of 20 to 90 μm; and / or, The porosity of the multi-stage microchannel is 38% to 42%; and / or, The tortuosity of the multi-stage microchannel is 1.8 to 2.3; and / or, The multi-stage micro-channels are distributed in a serpentine shape.

3. The microfluidics-EICP combined dynamic visualization monitoring system for heavy metal contaminated soil remediation process according to claim 1 is characterized in that: The microfluidic reaction module also includes: The anti-clogging output unit includes a multi-stage filtering structure and a backwashing pipeline. The aperture of the multi-stage filtering structure decreases sequentially, and the backwashing pipeline is connected to the multi-stage microchannel.

4. The microfluidics-EICP combined dynamic visualization monitoring system for heavy metal contaminated soil remediation process according to claim 3 is characterized in that: The anti-clogging unit is provided with a nitrogen backwashing device and a reversing valve. The nitrogen backwashing device is used to achieve backwashing by nitrogen injection. The backwashing pipeline is connected in parallel with the multi-stage microchannel through the reversing valve.

5. The microfluidics-EICP combined dynamic visualization monitoring system for heavy metal contaminated soil remediation process according to claim 1 is characterized in that: The substrate layer comprises borosilicate glass with a thickness of 0.5 to 1.5 mm; and / or, The ion selective electrode array includes Pb 2 + electrode, Cd 2 + electrode and composite pH electrode; and / or, The multimodal sensing module further includes a fiber demodulator, which is used to analyze the signal of the fiber grating sensor and output it to the printed circuit; and / or, The multimodal sensing module further includes a signal conditioning circuit, the ion selective electrode array is electrically connected to the printed circuit via the signal conditioning circuit, and the signal conditioning circuit is used to amplify electrode signals; and / or, The printed circuit includes a flexible printed circuit.

6. The microfluidics-EICP combined dynamic visualization monitoring system for heavy metal contaminated soil remediation process according to claim 1 is characterized in that: A flow channel observation window is also provided on the side of the microfluidic reaction module; The optical imaging unit includes a microscope and a camera, wherein the microscope is arranged opposite to the flow channel observation window for high-magnification observation of microstructures, and the camera is arranged opposite to the microscope for capturing and recording images; and / or, The spectrum analysis unit includes a fluorescence spectrometer and a Raman spectrometer, which are arranged on the side of the flow channel observation window. The fluorescence spectrometer is used to detect fluorescence signals, and the Raman spectrometer is used to detect molecular vibration information.

7. A dynamic visualization monitoring method for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination, characterized in that: The system comprises a dynamic visualization monitoring system for the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination as claimed in any one of claims 1 to 6, and further comprises at least the following steps: The microfluidic reaction module is subjected to surface activation treatment to form a urease immobilization interface; The heavy metal contaminated soil sample was mixed with the immobilized urease solution and then injected into the microfluidic reaction module; The heavy metal contaminated solution, the background electrolyte solution and the urea-calcium source mixed solution are sequentially added; Detecting physical and chemical properties through the multimodal sensing module and transmitting the signals to the data analysis module; Output visualization images through the data analysis module.

8. The method for dynamic visualization monitoring of the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination as claimed in claim 7, characterized in that: The step of performing surface activation treatment on the microfluidic reaction module to form a urease immobilization interface specifically includes: Cleaning the channel surface of the multi-stage microfluidic channel using an oxygen plasma cleaning machine; An aminosilanization reagent is used to modify the channel surface of the multi-stage microchannel to form a stable urease immobilization interface.

9. The method for dynamic visualization monitoring of the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination according to claim 7, characterized in that: The urea-calcium source mixed solution is perfused in a pulsed manner; and / or, The background electrolyte solution includes Pb 2+ Solution, Cd 2+ solution and NaCl solution, Pb 2+ The concentration is 500~1500mg / L, Cd 2+ The concentration is 100-300 mg / L, the NaCl solution is 0.05-0.15; and / or, The urea-calcium source mixed solution includes a urea solution and a CaCl2 solution, wherein the urea concentration gradient is 0.8-1.5M, and the CaCl2 concentration is 0.5-1.2M.

10. The method for dynamic visualization monitoring of the remediation process of heavy metal contaminated soil using a microfluidics-EICP combination according to claim 7, characterized in that: After the step of outputting the visualization image through the data analysis module, the following steps are further included: Reverse perfusion of deionized water to remove free precipitates; Injecting chelating solution to chelate residual heavy metal ions; Purge with nitrogen to dry the flow channel.

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