Device for observing migration of micro-nano iron particles in porous medium

Abstract

The invention discloses a device for observing migration of micro-nano iron particles in a porous medium, and belongs to the field of groundwater pollution remediation. The device comprises a liquid storage tank, a microfluidic system, an optical monitoring system, a receiving tank and a detection system. The liquid storage tank is used for storing a to-be-detected micro-nano iron particle material and carrying out fluorescent dyeing. The micro-fluidic system comprises an injection pump, a flow meter and a micro-fluidic chip, the micro-fluidic chip is made of a polydimethylsiloxane (PDMS) material and comprises a plurality of direct flow channels with liquid inlets and liquid outlets, and bionic porous network structures are designed in the channels. The optical monitoring system integrates an inverted fluorescence microscope and an sCMOS camera and controls monitoring records through computer software, and the receiving pool is used for collecting the nano-iron particle material flowing out of the micro-fluidic chip. The detection system is used for quantitatively testing and analyzing the content of the micro-nano iron in the receiving tank. The device can simply, quickly and accurately monitor the migration process of the micro-nano iron particles under different pore conditions.

Description

Technical Field

[0001] This invention relates to groundwater pollution remediation, and more particularly to a device for observing the migration of micro- and nano-sized iron particles in porous media. Background Technology

[0002] Micro- and nano-iron particles, as revolutionary remediation materials in the field of groundwater pollution remediation, have gained widespread attention and application in recent years. Micro- and nano-iron materials (including iron particles ranging from nanometer to micrometer scales) can effectively degrade various chlorinated organic pollutants and reduce and fix various heavy metal pollutants due to their high specific surface area and strong reducing properties, making them a powerful alternative to traditional remediation materials. In particular, with the increasing severity of groundwater pollution, the demand for efficient, precise, and economical remediation technologies is becoming more urgent, and in-situ injection remediation technology using micro- and nano-iron has shown broad application prospects.

[0003] In in-situ groundwater remediation, the transport distance of micro / nano iron particles in porous media determines their ability to effectively reach the contaminated area and react with pollutants; their transport capacity directly determines the quality of the remediation. Therefore, accurately assessing and predicting the transport capacity of micro / nano iron particles in porous media is a key step in improving the efficiency of groundwater pollution remediation. Existing simulation devices mostly use simplified porous media models (such as glass columns filled with uniform glass beads or standard sand), which lack accurate simulation of the complex structure of porous media, especially microporous structures. They cannot reflect key characteristics such as pore size distribution, tortuosity, and heterogeneity in real porous media, and different device models vary greatly, lacking standardized and refined design, making it impossible to achieve standardized testing of different micro / nano iron materials. In recent years, microfluidic technology has provided a new approach for the research of micro / nano particles. Based on the design of microfluidic chips, precise separation of different particles can be achieved, with advantages such as high control precision and convenient operation. However, current microfluidic technology patents mainly focus on particle separation technology rather than simulation of porous media. There is no real-time dynamic simulation device for particle transport in porous media, making it difficult to directly apply to the assessment of the transport capacity of micro- and nano-iron particles in the field of groundwater remediation.

[0004] In summary, traditional devices struggle to accurately simulate the characteristics of real porous media with different pore structures, and they also fail to achieve real-time dynamic monitoring and tracking of micro- and nano-iron particles in the pores. Consequently, they cannot accurately monitor and simulate the migration process and distribution of micro- and nano-iron particles in porous media. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a device for observing the migration of micro- and nano-iron particles in porous media, aiming to solve the shortcomings of existing devices and technologies that cannot accurately and objectively evaluate the migration ability of micro- and nano-particles in porous media.

[0006] Technical solution: A device for observing the migration of micro- and nano-sized iron particles in a porous medium, comprising a liquid storage tank, a microfluidic system, an optical monitoring system, a receiving tank, and a detection system connected in sequence; The storage tank is used to store and pre-treat the suspension of micro- and nano-iron particles; the microfluidic system includes a sample injection drive component and a microfluidic chip, used to simulate the transport process of the micro- and nano-iron particle suspension within the microfluidic chip; the optical monitoring system is used to monitor and record the transport dynamics of the micro- and nano-iron particles within the microfluidic chip in real time; the receiving tank is used to collect the effluent after transport by the microfluidic chip; and the detection system is used to quantitatively detect and characterize the micro- and nano-iron particles in the effluent.

[0007] Among them, the microfluidic chip has a multi-channel structure, which is used to finely simulate the pore structure characteristics of different porous media. Then, through the adjustable driving components, the microscopic visualization simulation of the transport process of micro- and nano-iron particle suspensions in different porous media can be realized.

[0008] Furthermore, the storage tank is a sealed box made of stainless steel, and is equipped with an inlet and outlet controlled by airtight valves, as well as an electric stirrer; the storage tank is used for fluorescent staining of micro-nano iron particles.

[0009] Furthermore, the injection drive component includes an injection pump and a flow meter, which is used to monitor and provide feedback on the injection parameters of the injection pump to inject the micro / nano iron particle suspension into the microfluidic chip at a set flow rate and velocity.

[0010] Furthermore, the microfluidic chip is made of polydimethylsiloxane and contains at least 6 parallel DC channels, each with an independent inlet and outlet. X and Y scale lines are marked between the inlet and outlet of each channel of the microfluidic chip.

[0011] Furthermore, the internal structure of the channel is a biomimetic porous knot reconstructed from CT scan data of the actual stratum porous medium and manufactured by two-photon polymerization 3D printing technology; the microfluidic chip is 4cm long, 3cm wide, and 0.2cm thick; the width of a single channel is 80μm, the depth is 60μm, the channel wall thickness is 20μm, and the center-to-center distance between adjacent channels is 100μm.

[0012] Furthermore, the optical monitoring system includes an inverted fluorescence microscope, an sCMOS camera, and a computer; the sCMOS camera is connected to the inverted fluorescence microscope to acquire dynamic images; the computer has built-in image acquisition and analysis software to control shooting parameters, record the migration process, and automatically identify and track particles based on deep learning algorithms.

[0013] Furthermore, the detection system includes an inductively coupled plasma spectrometer, a transmission electron microscope, and an X-ray diffractometer, used to quantify the content and characterize the physicochemical properties of micro and nano iron particles in the receiving cell.

[0014] Beneficial Effects: This invention organically combines a microfluidic chip with a porous media model to design a microfluidic chip with a multi-channel structure, capable of precisely simulating the pore structure characteristics of different porous media. Utilizing a controllable driving system, it achieves microscopic visualization simulation of the transport process of micro / nano iron particle suspensions in different porous media, highly replicating the transport behavior of micro / nano iron particles in actual pores. This significantly improves the consistency between simulation results and actual site conditions, providing a standardized testing platform for comparing and evaluating the transport performance of different micro / nano iron materials. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the device structure; Figure 2 This is a schematic diagram of a microfluidic chip structure.

[0016] In the picture: 1. Storage tank; 11. Airtight valve; 12. Electric stirrer; 2. Injection pump; 3. Flow meter; 4. Inverted fluorescence microscope; 5. sCMOS camera; 6. Computer; 7. Microfluidic chip; 71. Inlet; 72. Outlet; 73. DC channel; 74. Scale line; 8. Receiver; 9. Detection instrument; 10. Conduit. Detailed Implementation

[0017] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Example like Figure 1 As shown, the simulation device mainly includes: Storage tank 1 is a sealed negative pressure chamber made of stainless steel, equipped with an inlet and outlet controlled by an airtight valve 11, and an electric stirrer 12. First, open the airtight valve 11 and add the suspension of micro / nano iron particles to be tested into storage tank 1 through the inlet. Then, add the fluorescent staining agent rhodamine to the storage tank, close the airtight valve 11, and turn on the electric stirrer 12 to stir the solution for more than 30 minutes to fully stain the micro / nano iron particles. At this time, the solution becomes a red suspension.

[0019] The microfluidic system includes a sample introduction drive component and a microfluidic chip 7. The drive component includes a syringe pump 2 and a flow meter 3. The syringe pump 2 is used to introduce the suspension of micro-nano iron particles in the reservoir 1 into the microfluidic chip 7, and the flow rate and flow volume are controlled by the flow meter 3.

[0020] Among them, the syringe pump 2 is a micro-volume multi-channel electric syringe pump with six channels, a linear velocity adjustment resolution of 1μm / min, an error ≤±0.5%, a linear thrust range of 12-45 kgf, and a maximum stroke of 140 mm. The microfluidic chip 7 is made of polydimethylsiloxane, with dimensions of 4cm in length, 3cm in width, and 0.2cm in height, and is designed and manufactured using an etching process. Figure 2 As shown, it includes six DC channels 73 of different lengths, each channel having an inlet 71 and an outlet 72, with a center-to-center distance of 100 μm between adjacent channels. Each individual channel has a width of 80 μm, a depth of 60 μm, and a wall thickness of 20 μm. The channels 73 are designed based on two-photon polymerization 3D printing biomimetic technology, and their interiors consist of different skeleton structures 731 and interconnected pores 732, allowing micro / nano iron particles 733 to move within the channels 73. The inlets of each channel are connected to an electric syringe pump 2 via conduits 10, and the outlets are connected to a receiving pool 8 via conduits 10.

[0021] The optical monitoring system includes an inverted fluorescence microscope 4, an sCMOS camera 5, and a computer 6 with image acquisition software. The inverted fluorescence microscope 4 is connected to the sCMOS camera 5 and the computer 6 respectively. Under the control of the computer image acquisition software, dynamic image acquisition is performed on the microfluidic chip 7 placed under the lens to obtain relevant data information on the movement of micro- and nano-iron particles in it. The movement distance and distribution of micro- and nano-iron particles in the channel are obtained through the scale line 74.

[0022] The detection system 9 includes a series of detection instruments, such as inductively coupled plasma and transmission electron microscope, X-ray diffractometer, etc. The micro-nano suspension flowing out of the microfluidic chip 7 is collected through the receiving cell 8. After digestion, the iron content in the solution is measured by inductively coupled plasma. The micro-nano iron concentration and morphology of the flowing out of the microcontroller chip are quantitatively evaluated by characterization and analysis using transmission electron microscope, X-ray diffractometer, etc., loaded on a copper grid.

[0023] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A device for observing the migration of micro / nano iron particles in a porous medium, characterized in that, It includes a storage tank, a microfluidic system, an optical monitoring system, a receiving tank, and a detection system connected in sequence; The storage tank is used to store and stain the pretreated micro-nano iron particle suspension; the microfluidic system includes a sample injection drive component and a microfluidic chip, used to simulate the transport process of the micro-nano iron particle suspension within the microfluidic chip; The optical monitoring system is used to monitor and record the movement of micro- and nano-iron particles in the microfluidic chip in real time; the receiving cell is used to collect the effluent after being transported by the microfluidic chip. The detection system is used to quantitatively detect and characterize the micro- and nano-sized iron particles in the effluent. Among them, the microfluidic chip has a multi-channel structure, which is used to finely simulate the pore structure characteristics of different porous media. Then, through the adjustable driving components, the microscopic visualization simulation of the transport process of micro- and nano-iron particle suspensions in different porous media can be realized.

2. The device for observing the migration of micro / nano iron particles in porous media according to claim 1, characterized in that, The storage tank is a sealed box made of stainless steel, equipped with an inlet and outlet controlled by airtight valves, as well as an electric stirrer; the storage tank is used for storing and fluorescently staining suspensions of micro-nano iron particles.

3. The device for observing the migration of micro / nano iron particles in porous media according to claim 1, characterized in that, The injection drive assembly includes an injection pump and a flow meter. The flow meter is used to monitor and provide feedback on the injection parameters of the injection pump to inject the micro / nano iron particle suspension into the microfluidic chip at a set flow rate and velocity.

4. The device for observing the migration of micro / nano iron particles in porous media according to claim 3, characterized in that, The microfluidic chip is made of polydimethylsiloxane (PDMS) and contains at least 6 parallel DC channels. Each channel has an independent inlet and outlet. X and Y scale lines are marked between the inlet and outlet of each channel of the microfluidic chip.

5. The apparatus for observing the migration of micro / nano iron particles in porous media according to claim 4, characterized in that, The internal structure of the channel is a biomimetic porous structure reconstructed from CT scan data of the actual stratum porous medium and manufactured by two-photon polymerization 3D printing technology; the microfluidic chip is 4cm long, 3cm wide, and 0.2cm thick; the width of a single channel is 80μm, the depth is 60μm, the channel wall thickness is 20μm, and the center-to-center distance between adjacent channels is 100μm.

6. The apparatus for observing the migration of micro / nano iron particles in porous media according to claim 1, characterized in that, The optical monitoring system includes an inverted fluorescence microscope, an sCMOS camera, and a computer; the sCMOS camera is connected to the inverted fluorescence microscope to acquire dynamic images; the computer has built-in image acquisition and analysis software to control shooting parameters, record the migration process, and automatically identify and track particles based on deep learning algorithms.

7. The apparatus for observing the migration of micro / nano iron particles in porous media according to claim 1, characterized in that, The detection system includes an inductively coupled plasma mass spectrometer, a transmission electron microscope, and an X-ray diffractometer, used to quantify the content and characterize the physicochemical properties of micro and nano iron particles in the receiving cell.

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