Soil testing sensor and soil layer pollution testing device

Abstract

The application provides a soil detection sensor with a measuring needle and a soil layer pollution detection device, and belongs to the technical field of sensors.The soil detection sensor with a measuring needle comprises a measuring needle assembly and a detection device.The measuring needle assembly has a shell, and an inner cavity and an intermediate insulating layer attached to the inner wall of the shell are arranged in the shell.The lower end of the inner cavity is a solution containing space, and the lower end of the shell is used for inserting into soil and is provided with a small pore to allow soil solution to enter the solution containing space.The detection device is arranged in the inner cavity to detect soil.The sensor is of an insertion type, is convenient to use, and has high detection efficiency.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, and more specifically, relates to a needle-type soil detection sensor and a soil pollution detection device. Background Technology

[0002] Soil pollution risk management and remediation are crucial aspects of soil pollution prevention and control. Pollution investigation and remediation management of soil and groundwater in operating enterprises are key and challenging areas in my country's current and future battle against soil pollution. Operating enterprises undertake both production and environmental protection tasks. Traditional soil pollution investigation techniques, primarily relying on mechanical drilling sampling and laboratory testing, often suffer from significant site disturbance, prominent safety hazards, long work cycles, and stringent construction requirements. Currently, traditional soil pollution detection devices generally fail to meet the needs of operating enterprises for safe production and "low-cost, long-term effective" green and low-carbon pollution investigations. Therefore, designing a soil pollution micro-disturbance detection sensor adapted to the "production-while-investigating" requirements of operating enterprises is urgently needed. Summary of the Invention

[0003] The purpose of this invention is to provide a needle-type soil detection sensor and a soil pollution detection device to solve the problem that existing soil detection devices cannot meet the needs of enterprises to conduct investigations while producing.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a probe-type soil detection sensor is provided, comprising a probe assembly and detection devices; the probe assembly has a shell, an inner cavity inside the shell and an intermediate insulating layer attached to the inner wall of the shell; the lower end of the inner cavity is a solution-containing space, the lower end of the shell is used for insertion into the soil, and is provided with micropores to allow soil solution to enter the solution-containing space; the detection devices are all disposed in the inner cavity for detecting the soil;

[0005] The detection device includes an electrochemical detection unit, a miniature light source, a photodetector, optical fibers, a miniature temperature sensor, and a miniature pressure sensor. The electrochemical detection unit is located at the end of the housing for insertion into the soil and is used to detect pollutants in the soil electrochemically. The miniature light source emits the light signal required for detection. The photodetector receives the light signal after it has passed through the soil solution and converts it into an electrical signal. The optical fibers include an emitting optical fiber and an receiving optical fiber. One end of the emitting optical fiber is connected to the miniature light source, and the other end extends into the solution-containing space. One end of the receiving optical fiber is connected to the photodetector, and the other end extends into the solution-containing space. There is a gap between the receiving optical fiber and the end of the emitting optical fiber located in the solution-containing space to detect the solution between them. The miniature temperature sensor is connected to the housing and is used to detect the soil temperature. The miniature pressure sensor is located at the lower end of the housing, with its detection end passing through the housing, to detect the resistance to insertion into the soil.

[0006] In one possible implementation, based on the above technical solutions, the electrochemical detection unit includes a nanomaterial-modified electrode for detecting heavy metals. The nanomaterial-modified electrode includes a working electrode, a reference electrode, and a counter electrode. The surface of the working electrode is modified with nanomaterials that have selective adsorption and reactivity capabilities for specific heavy metal ions.

[0007] In one possible implementation, based on the above technical solutions, the electrochemical detection unit includes an enzyme-modified electrode for detecting organic pollutants, wherein an enzyme that specifically reacts to the target organic pollutant is immobilized on the surface of the enzyme-modified electrode.

[0008] In one possible implementation, in conjunction with the above technical solutions, the stylus-type soil detection sensor also includes a communication module installed inside the stylus assembly, used to receive data collected by the sensor and send it to an external receiving device.

[0009] In one possible implementation, based on the above technical solutions, the intermediate insulating layer is a mesh structure made of insulating and elastic material, and its surface is hydrophobic through the material's own properties or a hydrophobic coating to reduce water retention and make it easier for remaining water to form droplets, thus preventing the remaining water from flowing in streams or adhering to form conductive paths; the intermediate insulating layer is glued and fixed to the inner wall of the outer shell by an adhesive.

[0010] In one possible implementation, in conjunction with the above technical solutions, the probe-type soil detection sensor also includes a fixed bracket. The edge of the fixed bracket is press-fitted with the middle insulating layer to be fixed inside the housing by the middle insulating layer. The electrochemical detection unit, the miniature light source, the photodetector, the optical fiber and the miniature temperature sensor are all mounted on the fixed bracket.

[0011] The lower end of the outer shell has a conical head with a tiny orifice on it. The top of the conical head has a through hole for the detection end of the micro pressure sensor to pass through. A spring and a sealing ring are provided between the micro pressure sensor and the conical head. The sealing ring is located on the micro pressure sensor or on the outer periphery of the through hole. The spring is connected to both the micro pressure sensor and the outer periphery of the through hole, so that it pushes the micro pressure sensor away from the through hole in its natural state. A pressure rod is provided on the fixed bracket, which extends to the micro pressure sensor. It is used to press the micro pressure sensor when the fixed bracket is installed in place, so as to compress the spring and seal the micro pressure sensor with the outer periphery of the through hole through the sealing ring. This prevents large particles of mud and sand from entering the solution-containing space when inserted into the soil, which would affect the detection accuracy. This allows the detection end of the micro pressure sensor to pass through the through hole.

[0012] In one possible implementation, based on the above technical solutions, the head of the probe assembly is conical, and the angle of the conical surface is between 30° and 45°.

[0013] In one possible implementation, combining the above technical solutions, the probe-type soil detection sensor also includes a universal power supply, which is electrically connected to the communication module, electrochemical detection unit, miniature light source, photodetector, miniature temperature sensor, and miniature pressure sensor.

[0014] To achieve the above objectives, the present invention provides a soil pollution detection device comprising a needle-type soil detection sensor and a processor.

[0015] The aforementioned needle-type soil detection sensor device has a processor configured to perform the following operations: receive electrochemical signals sent by the electrochemical detection unit, electrical signals transmitted by the photodetector, temperature data detected by the miniature temperature sensor, and pressure data detected by the miniature pressure sensor; call a pre-stored calibration algorithm library to match the calculation model of the target pollutant; and output a comprehensive report on the pollutant type, concentration, spatial distribution, and soil physicochemical parameters.

[0016] The beneficial effects of the probe-type soil detection sensor provided by this invention are as follows: Compared with traditional soil detection methods, firstly, by using materials sensitive to different pollutants as detection electrodes and combining them with optical detection principles, this invention can more accurately detect the content of heavy metals and organic pollutants in the soil, improving the accuracy and specificity of the detection. For example, the high sensitivity of nanomaterial-modified electrodes for the detection of specific heavy metal ions and the specific reaction detection of enzyme-modified electrodes for organic pollutants can more accurately determine the soil pollution status.

[0017] Second, this invention designs the soil detection sensor as an insertable type, allowing for direct on-site detection without the need for complex sampling and sample transportation. Simultaneously, the soil contamination detection device can process and display detection results in real time, greatly simplifying the detection process, enabling rapid on-site detection, and improving detection efficiency.

[0018] Third, previous detection technologies often only obtain data on a single or limited number of indicators, making it difficult to comprehensively assess soil environmental quality. The probe-type soil detection sensor provided by this invention can not only detect pollutants, but also obtain soil temperature and insertion resistance data through temperature and pressure sensors. Combining these data with pollutant detection data provides a more comprehensive understanding of the soil environmental condition, offering richer and more accurate data support for soil pollution control and ecological restoration. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of the probe-type soil detection sensor provided in an embodiment of the present invention;

[0021] Figure 2 Provided for embodiments of the present invention Figure 1 A schematic diagram of the structure of A described in the figure;

[0022] Figure 3 This is a schematic diagram showing the positional structure of the outer shell, intermediate insulating layer, and inner cavity of the probe assembly provided in an embodiment of the present invention;

[0023] Figure 4 A schematic diagram of the positional structure of the miniature light source, optical fiber, and photodetector provided in an embodiment of the present invention;

[0024] Figure 5 Provided for embodiments of the present invention Figure 4 A schematic diagram of the structure of B described in the figure;

[0025] Figure 6 This is a schematic diagram of the location and structure of the soil pollution detection device provided in another embodiment of the present invention;

[0026] The labels for the attached figures are as follows:

[0027] 10. Probe assembly; 101. Housing; 102. Intermediate insulating layer; 103. Inner cavity; 104. Sealing cap; 11. Electrochemical detection unit; 12. Miniature light source; 13. Photodetector; 14. Optical fiber; 15. Miniature temperature sensor; 16. Miniature pressure sensor; 17. Thermally conductive silicone; 18. Spring; 19. Sealing ring;

[0028] 20. Communication module;

[0029] 30. Fixed bracket; 31. Pressure bar;

[0030] 40. Universal power supply;

[0031] 50. Processor; Detailed Implementation

[0032] To make the technical problems, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the described embodiments are only a part of the embodiments of this application, not all of them. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] It should be further noted that the accompanying drawings and embodiments of the present invention mainly describe the concept of the present invention. Based on this concept, some specific forms and arrangements of connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, under the premise that those skilled in the art understand the concept of the present invention, they can implement the above-mentioned specific forms and arrangements in a well-known manner.

[0034] When a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0035] The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself. The terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0036] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, and "several" means one or more, unless otherwise explicitly specified.

[0037] The present invention will now describe the needle-type soil detection sensor and the soil pollution detection device provided by the present invention.

[0038] like Figure 1 and Figure 5As shown, the first embodiment of the present invention provides a probe-type soil detection sensor including a probe assembly and detection devices; the probe assembly has a housing 101, an inner cavity 103 and an intermediate insulating layer 102 attached to the inner wall of the housing 101; the lower end of the inner cavity 103 is a solution-containing space, and the lower end of the housing 101 is used for insertion into the soil and is provided with micropores to allow soil solution to enter the solution-containing space; the detection devices are all disposed in the inner cavity 103 for detecting the soil; wherein, the detection devices include an electrochemical detection unit 11, a miniature light source 12, a photodetector 13, an optical fiber 14, a miniature temperature sensor 15 and a miniature pressure sensor 16; the electrochemical detection unit 11 is disposed at the end of the housing 101 used for insertion into the soil, and is used for detection by electrochemical means. The device measures pollutants in the soil. A miniature light source 12 emits the light signal required for detection. A photodetector 13 receives the light signal after it has passed through the soil solution and converts it into an electrical signal. An optical fiber 14 includes an emitting optical fiber and an incoming optical fiber. One end of the emitting optical fiber is connected to the miniature light source 12, and the other end extends into the solution-containing space. One end of the incoming optical fiber is connected to the photodetector 13, and the other end extends into the solution-containing space. There is a gap between the incoming optical fiber and the end of the emitting optical fiber located in the solution-containing space to detect the solution between them. A miniature temperature sensor 15 is connected to the housing 101 to detect the soil temperature. A miniature pressure sensor 16 is located at the lower end of the housing 101, and its detection end passes through the housing 101 to detect the resistance to insertion into the soil. The head of the probe assembly is conical, and the angle of the conical surface is between 30° and 45°. The stylus-type soil detection sensor also includes a universal power supply 40, which is electrically connected to the communication module, electrochemical detection unit 11, miniature light source 12, photodetector 13, miniature temperature sensor 15, and miniature pressure sensor 16. The stylus-type soil detection sensor also includes a communication module, installed inside the stylus assembly, used to receive data collected by the sensor and transmit it to an external receiving device.

[0039] Before starting work, staff will select a series of testing points based on the actual situation. During work, staff will insert the head of the probe assembly 10 into the soil to a depth (10-50cm). After the head of the probe assembly 10 is inserted into the soil, it will be left to stand for a period of time (5-10 minutes) to allow sufficient time for the soil solution to enter the lower end of the inner cavity 103 of the probe assembly 10. The lower end of the inner cavity 103 is used to contain the soil solution. Specifically, the probe assembly 10 has a shell 101, inside which is provided the inner cavity 103 and an intermediate insulating layer 102 attached to the inner wall of the shell 101. The lower end of the shell 101 is used to insert into the soil and has micropores. These micropores allow the soil solution to enter the solution-containing space but prevent sand and gravel from entering, facilitating subsequent testing. The intermediate insulating layer 102 is used to prevent signal interference. The detection devices are all set in the inner cavity 103 for soil detection. The inner cavity 103 of the probe assembly 10 integrates... An electrochemical detection unit 11, a miniature light source 12, a photodetector 13, and an optical fiber 14 are installed. The electrochemical detection unit 11 is located at the end of the housing 101 that is inserted into the soil, and detects pollutants in the soil electrochemically. The miniature light source 12 is a miniature LED light source with a wavelength range of 300-800nm, used to emit the light signal required for detection. The photodetector 13 receives the light signal after it has passed through the soil solution and converts it into an electrical signal. The optical fiber 14 has a diameter range of 0.1-0.5mm and includes an output optical fiber and an input optical fiber. One end of the output optical fiber is connected to the miniature light source 12, and the other end extends into the solution-containing space. One end of the input optical fiber is connected to the photodetector 13, and the other end extends into the solution-containing space, with a gap between it and the end of the output optical fiber located in the solution-containing space, to detect the solution between them.

[0040] The probe assembly 10 has a sharp, conical head with an angle between 30° and 45° for easy insertion into the soil. A miniature pressure sensor 16 is located at the lower end of the housing 101, with its detection end passing through the housing 101 to detect the resistance to soil insertion. The miniature pressure sensor 16 is connected to the housing 101 to detect soil temperature. The miniature temperature sensor 15 and the miniature pressure sensor 16 can monitor the soil temperature and insertion resistance at the insertion depth in real time, providing data support for determining soil texture. Specifically, the miniature temperature sensor 15 is integrated into the side wall of the probe assembly 10 and contacts the soil via thermally conductive silicone 17 to monitor the temperature at the insertion depth in real time. The miniature pressure sensor 16 is embedded in the lower end of the probe assembly 10 and passes through the housing 101; its detection end directly interacts with the soil to measure the resistance to soil insertion.

[0041] When the probe assembly 10 is inserted into the soil, the soil solution enters the solution-containing space through the tiny pores at the lower end of the outer shell 101. For heavy metal detection, on the one hand, electrochemical stripping voltammetry is used, applying a specific potential to the working electrode modified with nanomaterials to cause the heavy metal ions adsorbed on the electrode surface to undergo a redox reaction, and the heavy metal content is determined by detecting the current signal; on the other hand, optical heavy metal ion fluorescent probe technology is used, in which fluorescent probes that selectively bind to specific heavy metal ions and can generate a fluorescent response are pre-loaded inside the probe. When the heavy metal ions in the soil solution bind to the fluorescent probes, they generate characteristic fluorescent signals under the excitation of specific wavelength light emitted by the micro light source 12. The photodetector 13 receives the fluorescent signal and converts it into an electrical signal. For the detection of organic pollutants, one approach is based on the specific reaction between enzymes and substrates. Enzymes on enzyme-modified electrodes react with target organic pollutants, generating changes in electrical signals. Another approach employs spectrophotometry. A miniature light source 12 emits composite light. After passing through the soil solution, organic pollutants in the soil absorb light of specific wavelengths. A photodetector 13 receives the transmitted light, and according to the Lambert-Beer law, the concentration of organic pollutants is determined by detecting changes in light absorbance. Data from temperature and pressure sensors, along with signals from the detection electrodes and optical detection signals, are transmitted via built-in circuitry to the processor 50 of the soil contamination detection device.

[0042] Specifically, taking the insertion direction of the probe assembly 10 as a reference, the head of the probe assembly 10 is the lower end, the tail of the probe assembly 10 is the upper end, the miniature light source 12 is on top, and the photodetector is on the bottom. The light emitted by the miniature light source 12 is transmitted downward to the solution-containing space through the light-emitting optical fiber in the optical fiber 14. When the light signal emitted by the miniature light source 12 interacts with the soil solution between the light-emitting optical fiber and the light-receiving optical fiber, the light signal is reflected or transmitted by the soil solution and received by the photodetector through the light-receiving optical fiber.

[0043] Furthermore, the stylus-type soil detection sensor also includes a general-purpose power supply 40 and a communication module 20. The general-purpose power supply 40 is electrically connected to the communication module 20, the electrochemical detection unit 11, the miniature light source 12, the photodetector 13, the miniature temperature sensor 15, and the miniature pressure sensor 16. The communication module 20 is installed inside the stylus assembly 10 and is used to receive data collected by the sensor and transmit it to an external receiving device.

[0044] The universal power supply 40 can use a lithium-ion battery and outputs a stable voltage through a DC-DC converter. Battery life is ≥100 hours and supports USB-C fast charging.

[0045] Compared with existing technologies, this invention, by employing materials sensitive to different pollutants as detection electrodes and combining them with optical detection principles, can more accurately detect the content of heavy metals and organic pollutants in soil, improving the accuracy and specificity of detection. For example, the high sensitivity of nanomaterial-modified electrodes for the detection of specific heavy metal ions and the specific reaction detection of organic pollutants by enzyme-modified electrodes can more accurately determine the soil pollution status.

[0046] Second, this invention designs the soil detection sensor as an insertable type, allowing for direct on-site detection without the need for complex sampling and sample transportation. Simultaneously, the main unit of the soil contamination detection device can process and display the detection results in real time, greatly simplifying the detection process, enabling rapid on-site detection, and improving detection efficiency.

[0047] Third, previous detection technologies often only obtain data on a single or limited number of indicators, making it difficult to comprehensively assess soil environmental quality. The probe-type soil detection sensor provided by this invention can not only detect pollutants, but also obtain soil temperature and insertion resistance data through temperature and pressure sensors. Combining these data with pollutant detection data provides a more comprehensive understanding of the soil environmental condition, offering richer and more accurate data support for soil pollution control and ecological restoration.

[0048] The present invention provides a further specific embodiment based on the first embodiment as follows: the electrochemical detection unit 11 includes a nanomaterial modified electrode for detecting heavy metals. The nanomaterial modified electrode includes a working electrode, a reference electrode and a counter electrode. The surface of the working electrode is modified with nanomaterials that have selective adsorption and reaction capabilities for specific heavy metal ions.

[0049] To detect heavy metals in soil pollutants, the electrochemical detection unit 11 includes a nanomaterial-modified electrode for detecting heavy metals. The nanomaterial-modified electrode includes a working electrode, a reference electrode, and a counter electrode. The surface of the working electrode is modified with nanomaterials that have selective adsorption and reactivity capabilities for specific heavy metal ions, such as graphene oxide nanomaterials. These graphene oxide nanomaterials can be used to selectively adsorb lead ions, chromium ions, or arsenic ions in the soil solution.

[0050] Based on the first embodiment, the present invention provides another specific embodiment as follows: the electrochemical detection unit 11 includes an enzyme-modified electrode for detecting organic pollutants, wherein an enzyme that specifically reacts to the target organic pollutant is immobilized on the surface of the enzyme-modified electrode.

[0051] Specifically, to detect organic pollutants in soil, the electrochemical detection unit 11 also includes an enzyme-modified electrode for detecting organic pollutants. The working electrode surface of the enzyme-modified electrode is immobilized with laccase or peroxidase, which generates a current or voltage signal by catalyzing the redox reaction of the target pollutant to detect the content of organic pollutants. The laccase-modified electrode can detect bisphenol A, phenol, or p-nitrophenol in wastewater; while the peroxidase electrode detects phenols and aromatic compounds (such as pentachlorophenol) and organophosphorus pesticide residues (such as parathion).

[0052] Furthermore, a paper titled "Electrochemical detection of organophosphorus pesticides based on amino acids conjugated nanoenzyme modified electrodes" (DOI: 10.1016 / i.snb.2019.02.007) published in the international academic journal *Sens. Actuators B: Chem.* discovered that nanozymes attached to amino acids (AAs) serine (S), histamine (H), and glutamate (E) facilitate the catalysis of organophosphorus pesticides (OPs) to form electroactive p-nitrophenol (PNP). This phenomenon follows the proton transfer relay mechanism found in biomimetic hydrolases. Therefore, an electrochemical method for detecting organophosphorus pesticides using S, H, and E conjugated TiO2NPS (NPs) modified electrodes is proposed. Using TiO2NPs as a carrier, the attached S, H, and E exhibit hydrolytic activity towards organophosphorus pesticides; therefore, the behavior of TiO2NPS-AAs is similar to that of hydrolyzed nanozymes. OPs (methyl parathion, methyl parathion, and ethyl parathion) can generate electrochemically active PNPs on the surface of this nanozyme-modified electrode, and OPs can be quantified through the electrochemical signal of the PNPs. This technique is selective for organophosphorus pesticides with p-nitrophenol groups. The detection limits for methyl parathion, methyl parathion, and ethyl parathion are approximately 0.2 mm, with a working range of two orders of magnitude. This detection technique can be applied to the detection of organophosphorus pesticides in soil pollution with high detection accuracy. Therefore, the working electrode surface of the enzyme-modified electrode can also be equipped with amino acid conjugated nanozymes to catalyze the hydrolysis of organic pollutants to generate electroactive substances, achieving electrochemical detection.

[0053] like Figure 3As shown, based on the first embodiment, the present invention provides a specific embodiment as follows: the intermediate insulating layer 102 is a mesh structure made of insulating and elastic material, and the surface is hydrophobic through the material's own properties or a hydrophobic coating to reduce water retention and make the remaining water more likely to form droplets, avoiding the remaining water from flowing in streams or adhering to form conductive paths; the intermediate insulating layer 102 is glued and fixed to the inner wall of the outer shell 101 by an adhesive.

[0054] The intermediate insulation layer 102 is made of elastic polytetrafluoroethylene (PTFE) material with a three-dimensional mesh structure, a mesh density of 20 meshes / inch, a wire diameter of 0.15 mm, and a porosity of 75%. This material itself has excellent chemical stability and hydrophobicity, with a surface contact angle greater than 110°, effectively reducing moisture retention without the need for additional coatings. To further enhance the hydrophobic properties, a 5-10 μm thick fluorocarbon coating is deposited on the mesh surface using a plasma polymerization process, increasing the contact angle to over 135°. This coating is firmly bonded to the PTFE matrix and showed no peeling after 500 bending tests.

[0055] The intermediate insulation layer 102 is bonded to the inner wall of the outer casing 101 using a two-component epoxy resin adhesive. Before construction, the inner wall of the outer casing 101 is roughened by sandblasting to Ra 3.2-6.3μm and then degreased with acetone. The adhesive is mixed in a 1:1 ratio and applied evenly to the inner wall of the outer casing 101 at 0.5mm intervals using an automatic dispensing device. The pre-fabricated insulation mesh structure is stretched by 5% along the axial direction of the outer casing 101 and then bonded together. A pressure of 0.08MPa is applied using a vacuum adsorption device and held for 30 minutes to ensure that the adhesive fully penetrates the mesh gaps. After curing, a uniformly thick adhesive layer is formed, meeting the requirements for long-term use.

[0056] The flexible design of the mesh structure allows it to adapt to the thermal expansion and contraction of the housing 101 within a temperature range of -20℃ to 60℃, with a maximum deformation of 2% without delamination. When moisture seeps in through the tiny pores of the housing 101, the hydrophobic mesh surface forces the moisture to quickly form droplets with a diameter ≥2mm, which then slide down along the mesh pores into the solution-containing space under gravity. Testing showed that after 24 hours in an environment with 95% relative humidity, the residual water content on the insulation layer surface was ≤0.1g / m², and no water streams or conductive pathways were observed. This design effectively avoids the risk of electrochemical corrosion and leakage caused by moisture accumulation, ensuring the long-term stable operation of the internal detection devices.

[0057] like Figure 1 and Figure 4As shown, based on the first embodiment, the present invention provides another specific embodiment as follows: the probe-type soil detection sensor further includes a fixed bracket 30, the edge of the fixed bracket 30 is press-fitted with the intermediate insulating layer 102 so as to be pressed and fixed in the outer shell 101 by the intermediate insulating layer 102. The electrochemical detection unit 11, the miniature light source 12, the photodetector 13, the optical fiber 14 and the miniature temperature sensor 15 are all mounted on the fixed bracket 30.

[0058] The lower end of the housing 101 has a conical head, a tiny hole is provided on the conical head, and the top of the conical head is provided with a through hole for the detection end of the micro pressure sensor 16 to pass through.

[0059] A spring 18 and a sealing ring 19 are provided between the miniature pressure sensor 16 and the conical head. The sealing ring 19 is provided on the miniature pressure sensor 16 or on the outer periphery of the through hole. The spring 18 is connected to the miniature pressure sensor 16 and the outer periphery of the through hole respectively, so as to push the miniature pressure sensor 16 away from the through hole in the natural state.

[0060] A pressure rod 31 is provided on the fixed bracket 30. The pressure rod 31 extends to the micro pressure sensor 16 and is used to press the micro pressure sensor 16 when the fixed bracket 30 is installed in place, so as to compress the spring 18 and seal the micro pressure sensor 16 with the outer periphery of the through hole through the sealing ring 19, so as to prevent large particles of mud and sand from entering the solution containing space when inserted into the soil, which would affect the detection accuracy, and allow the detection end of the micro pressure sensor 16 to pass through the through hole.

[0061] The fixing bracket 30 is injection molded from high-strength polycarbonate with an outer diameter of 18.5mm and an inner diameter of 18mm for the intermediate insulation layer 102. The fixing bracket 30 and the intermediate insulation layer 102 are interference-fitted. The edge of the fixing bracket 30 is machined with an annular groove 1.5mm wide and 0.8mm deep, with an embedded nitrile rubber O-ring. This effectively prevents soil solution from seeping into the upper part of the inner cavity 103 along the gap between the bracket and the insulation layer, avoiding corrosion of precision electronic components such as the miniature light source 12 and the photodetector 13. During assembly, an axial force is applied using a special tool to compress the outer diameter of the fixing bracket to 17.8mm and then push it into the outer shell 101. The radial clamping force is generated by the elastic deformation of the intermediate insulation layer 102 to ensure that it does not loosen under vibration.

[0062] Furthermore, a top cover 104 is provided at the upper end of the outer shell 101, and a vent hole is provided on the top cover 104 to facilitate the entry of soil solution into the solution-containing space at the lower end of the inner cavity 103; the top cover 104 is screwed to the upper end of the outer shell 101 by a threaded structure; after the top cover 104 is tightened, the inside of the top cover 104 abuts against the upper end of the fixing bracket 30, and the pressure rod 31 at the bottom of the fixing bracket 30 abuts against the miniature pressure sensor 16. At this time, the position of the miniature pressure sensor 16 is fixed, and its detection end extends out of the lower end of the outer shell 101; at the same time, the spring 18 between the miniature pressure sensor 16 and the through hole is in a compressed state. Under the force of the spring 18, the miniature pressure sensor 16 is further pressed out of the lower end of the housing 101. In addition, this design is mainly to allow the operator to unscrew the top cover 104 after a test to easily remove the fixing bracket 30. Then, under the action of the spring 18, the miniature pressure sensor 16 is pushed open, so that the inner cavity 103 is connected to the through hole. After that, the inner cavity 103, especially the solution containing space and the tiny pores on the conical head, can be directly rinsed with rinsing water or high-pressure rinsing water. The rinsing water can carry impurities directly out from the through hole and the tiny pores to avoid affecting the test results in the next use.

[0063] Meanwhile, the miniature pressure sensor 16 is provided with a waterproof structure to protect the detection device inside the probe assembly 10 from moisture intrusion. The waterproof structure can be made of resin sealant material, that is, resin sealant is applied to the place where the miniature pressure sensor 16 contacts the housing 101, or a waterproof sleeve can be provided on the outside of the miniature pressure sensor 16.

[0064] The electrochemical detection unit 11, the miniature light source 12, the photodetector 13 and other detection devices are mounted on the fixed bracket 30 through threaded holes. The optical fiber 14 is sealed to the fixed bracket 30 with a metal ferrule connector to ensure that the optical path collimation error is ≤0.05°.

[0065] The conical head of the outer shell 101 is integrally molded using a molding process, with the cone angle strictly controlled at 35°±1° to balance insertion resistance and structural strength. Multiple micro-pores are evenly distributed on the cone surface. A through-hole is provided at the top of the head, and a sealing groove is machined into the inner wall of the through-hole for installing a sealing ring 19. This sealing ring 19 has an inner diameter of 2.5mm, a wire diameter of 1.8mm, and a compression rate set at 25% to ensure reliable sealing.

[0066] The miniature pressure sensor 16 is a ceramic piezoresistive sensor. A cylindrical boss is designed at the tail of the sensor, which is clearance-fitted with the inner diameter of the spring 18.

[0067] A pressure rod 31 extends vertically from the bottom of the fixed bracket 30, with the end of the pressure rod 31 having a contact area ≥3mm² with the tail of the miniature pressure sensor 16. When the fixed bracket 30 is pressed into place, the pressure rod 31 displaces axially by 4mm, compressing the spring 18 to a working height of 12mm. At this point, the spring force is 14.4N, ensuring that the sensor detection end extends 1mm beyond the through hole and forms an effective seal. Testing shows that this sealing structure can withstand a water pressure of 0.3MPa, meeting the requirements for high-pressure flushing.

[0068] To achieve the above objectives, the present invention further adopts the following technical solution: providing a soil pollution detection device including a probe-type soil detection sensor and a processor 50; the processor 50 is configured to perform the following operations: receiving electrochemical signals sent by an electrochemical detection unit 11, electrical signals transmitted by a photodetector 13, temperature data detected by a miniature temperature sensor 15, and pressure data detected by a miniature pressure sensor 16; calling a pre-stored calibration algorithm library to match the calculation model of the target pollutant; and outputting a comprehensive report on the pollutant type, concentration, spatial distribution, and soil physicochemical parameters.

[0069] like Figure 6 As shown, the layer pollution detection device provided by the present invention mainly consists of a stylus-type soil detection sensor and a processor 50. The stylus-type soil detection sensor serves as a front-end detection device, responsible for collecting various types of data in the soil; the processor 50 serves as a core processing unit, analyzing and processing the data collected by the sensor, and finally outputting the detection results.

[0070] The detection principle of the soil pollution detection device in this invention is as follows: When the probe is inserted into the soil, the soil solution comes into contact with the electrochemical detection unit 11 and begins to operate. For heavy metal detection, the working electrode of the nanomaterial-modified electrode selectively adsorbs and reacts with specific heavy metal ions due to the surface-modified nanomaterials, generating an electrochemical signal. For organic pollutant detection, the enzyme fixed on the surface of the enzyme-modified electrode specifically reacts with the target organic pollutant, triggering a change in the electrochemical signal. Simultaneously, the miniature light source 12 emits the light signal required for detection, which is transmitted to the soil solution via the optical fiber 14. After interacting with the pollutant, the photodetector 13 receives the light signal and converts it into an electrical signal. The miniature temperature sensor 15 detects the soil temperature in real time, and the miniature pressure sensor 16 detects the soil insertion resistance. These data provide important information for subsequent analysis.

[0071] The processor 50 is connected to a probe-type soil detection sensor, receiving electrochemical signals from the electrochemical detection unit 11, electrical signals from the photodetector 13, temperature data from the miniature temperature sensor 15, and pressure data from the miniature pressure sensor 16. The processor 50 internally stores a calibration algorithm library. Upon receiving data, it calls relevant algorithms from the library based on data characteristics and preset rules to match the calculation model of the target pollutant. For example, for electrochemical and optical signals, it performs comprehensive analysis combined with temperature and pressure data to determine the type and concentration of pollutants. After determining the type and concentration of pollutants, the processor 50 uses a specific spatial distribution algorithm, combined with the location information of the detection points, to derive the spatial distribution of the pollutants. Simultaneously, using temperature and pressure data, and a preset soil physicochemical parameter calculation model, it calculates the soil's physicochemical parameters. Finally, the processor 50 integrates the pollutant type, concentration, spatial distribution, and soil physicochemical parameters, outputting a comprehensive report that presents the soil's pollution status and physicochemical properties in an intuitive manner.

[0072] This design enables the soil contamination detection device to achieve comprehensive and accurate detection of soil pollution. The stylus-type soil detection sensor is directly inserted into the soil for on-site testing, avoiding complex sampling and transportation processes and reducing errors. The powerful data processing capabilities of the processor and the pre-stored algorithm library ensure the accuracy and reliability of the detection results. The comprehensive output report provides comprehensive and accurate data support for soil pollution remediation, ecological restoration, and agricultural production, demonstrating high practical value.

[0073] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A probe-type soil testing sensor, characterized by, The utility model relates to a kind of soil detection sensors, including: Measuring needle assembly (10), with shell (101), the inner cavity (103) and the intermediate insulating layer (102) of being attached to the inner wall of the shell (101) are equipped in the shell (101);The lower end of the inner cavity (103) is solution containing space, the lower end of the shell (101) is used to be inserted into soil, and is equipped with small pore, to allow soil solution to enter solution containing space; Detection device, all be equipped in the inner cavity (103), to detect soil; Wherein, the detection device includes: Electrochemical detection unit (11), is equipped in the one end of the shell (101) for inserting soil, for detecting the pollutant in soil by electrochemical method; Miniature light source (12), for emitting the light signal required for detection; Light detector (13), for receiving the light signal after the action of soil solution, and it is converted into electric signal; Optical fiber (14), including light-out optical fiber and light-in optical fiber, the light-out optical fiber one end is connected with the miniature light source (12), and the other end extends to the solution containing space;The light-in optical fiber one end is connected with the light detector (13), and the other end extends to the solution containing space and has gap between the light-out optical fiber one end in the solution containing space, to detect the solution between them; Miniature temperature sensor (15), is connected with the shell (101), for detecting soil temperature;And Miniature pressure sensor (16), is arranged in the lower end of the shell (101), and detection end penetrates the shell (101), to detect the resistance of insertion soil.

2. The soil detection sensor according to claim 1, wherein: The electrochemical detection unit (11) comprises a nanomaterial modified electrode for detecting heavy metals, and the nanomaterial modified electrode comprises a working electrode, a reference electrode and a counter electrode, and the surface of the working electrode is modified with nanomaterials having selective adsorption and reaction capacity for specific heavy metal ions.

3. The soil detection sensor according to claim 1, wherein: The electrochemical detection unit (11) comprises an enzyme modified electrode for detecting organic pollutants, and the surface of the enzyme modified electrode is fixed with enzymes having specific reaction for target organic pollutants.

4. The soil detection sensor according to claim 1, further comprising a communication module (20) installed inside the measuring needle assembly (10) for receiving data collected by the sensor and sending the data to an external receiving device.

5. The soil detection sensor according to claim 1, wherein: The intermediate insulating layer (102) is a grid structure made of insulating and elastic material, and the surface thereof has hydrophobicity through material properties or hydrophobic coating, so as to reduce the residence of water and make the remaining water more likely to form droplets, avoiding the remaining water flowing in strands or adhering to form a conductive path; The intermediate insulating layer (102) is fixed on the inner wall of the shell (101) by adhesive. ​ 6. The soil testing sensor according to claim 1, wherein: the soil testing sensor further comprises a fixing support (30) with an edge in interference fit with the intermediate insulation layer (102) to be pressed and fixed in the shell (101) through the intermediate insulation layer (102), and the electrochemical detection unit (11), the micro light source (12), the light detector (13), the optical fiber (14) and the micro temperature sensor (15) are all mounted on the fixing support (30). The lower end of the shell (101) has a conical head, the micro aperture is arranged on the conical head, and the top end of the conical head is provided with a through hole for the detection end of the micro pressure sensor (16) to pass through. The micro pressure sensor (16) and the conical head are provided with a spring (18) and a sealing ring (19), the sealing ring (19) is arranged on the micro pressure sensor (16) or the outer periphery of the through hole, and the spring (18) is connected with the micro pressure sensor (16) and the outer periphery of the through hole respectively to push the micro pressure sensor away from the through hole in a natural state. The fixing support (30) is provided with a pressing rod (31) extending to the micro pressure sensor (16) to press the micro pressure sensor (16) when the fixing support (30) is installed in place, so that the spring (18) is compressed, the micro pressure sensor (16) is sealed with the outer periphery of the through hole through the sealing ring (19), and the detection end of the micro pressure sensor (16) passes through the through hole.

7. The soil testing sensor according to claim 6, wherein: the conical head is a conical structure, and the angle of the conical surface is between 30° and 45°.

8. The soil testing sensor according to claim 4, wherein: the soil testing sensor further comprises a general power supply (40) electrically connected with the communication module (20), the electrochemical detection unit (11), the micro light source (12), the light detector (13), the micro temperature sensor (15) and the micro pressure sensor (16). The soil testing sensor according to any one of claims 1-8; The processor (50) is configured to perform the following operations: receive the electrochemical signal sent by the electrochemical detection unit (11), the electrical signal transmitted by the light detector (13), the temperature data detected by the micro temperature sensor (15) and the pressure data detected by the micro pressure sensor (16); 9. A soil layer contamination detecting apparatus characterized by comprising: call the pre-stored calibration algorithm library and match the calculation model of the target pollutant; output the comprehensive report of the types, concentrations, spatial distributions of pollutants and soil physical and chemical parameters. ​ ​ ​ ​

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