An electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations

Abstract

The present invention discloses a soil heavy metal electrochemical detector integrating soil sample pretreatment operations. The housing assembly includes a bottom plate and a housing body assembly fixedly covered on the upper part of the bottom plate. A partition plate is fixedly arranged in the middle of the upper part of the bottom plate, and the bottom plate is separated into two parts, front and back, by the partition plate. A plurality of liquid storage bottle assemblies are arranged on the back of the housing assembly. A driving assembly is arranged in the front part of the bottom plate, and a control assembly is arranged above the driving assembly. In the back part of the bottom plate, a pretreatment I assembly, a pretreatment II assembly, and a pretreatment III assembly are successively arranged from bottom to top. A liquid transportation assembly is arranged on the right side of the pretreatment III assembly, and a detection assembly is arranged inside the liquid transportation assembly. The present invention integrates the soil sample pretreatment process, which can improve the accuracy of soil heavy metal electrochemical detection. The high integration and high automation of the detector enable the operation to only require adding the soil sample to be tested and setting parameters, and the remaining operations can be automatically performed by the detector, effectively improving the detection efficiency and greatly liberating human labor.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy metal detection, and particularly to a soil heavy metal electrochemical detector integrating soil sample pretreatment operations. Background Art

[0002] Soil heavy metal pollution poses a great threat to life safety as a large number of biologically non-degradable and toxic-accumulative heavy metals accumulate in the human body through the food chain. Therefore, detecting soil heavy metal pollution is of great significance.

[0003] Electrochemical detection is a detection technology capable of detecting trace heavy metals and can detect heavy metals in soil with relatively high precision. However, this detection method can only detect heavy metals in the free state, and a large amount of organic matter present in the soil will complex with the free heavy metals to form complexes that are difficult to detect by electrochemical methods, thereby reducing the detection accuracy of soil heavy metals. Therefore, before performing electrochemical detection of soil heavy metals, it is necessary to pretreat the soil to be tested to achieve the most accurate detection of soil heavy metal concentration. However, the operation of pretreating the soil is cumbersome and requires professional equipment in the laboratory, consuming a large amount of time and energy of experimental personnel. Therefore, a soil heavy metal electrochemical detector integrating soil sample pretreatment operations with high integration and automation is needed. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide a soil heavy metal electrochemical detector integrating soil sample pretreatment operations.

[0005] Technical Solution: The soil heavy metal electrochemical detector integrating soil sample pretreatment operations of the present invention includes a housing assembly. The housing assembly includes a bottom plate and a housing body assembly fixedly covered on the upper part of the bottom plate. A partition is fixedly provided in the middle of the upper part of the bottom plate, and the partition divides the bottom plate into two parts, front and back; a plurality of liquid storage bottle assemblies are provided on the back of the housing assembly. A driving assembly is provided in the front part of the bottom plate, and a control assembly is provided above the driving assembly. In the back part of the bottom plate, a pretreatment I assembly, a pretreatment II assembly, and a pretreatment III assembly are provided in sequence from bottom to top; a liquid transportation assembly is provided to the right of the pretreatment III assembly, and a detection assembly is provided inside the liquid transportation assembly.

[0006] Further, the housing body assembly includes a housing body and an upper cover. A screen is fixedly provided on the upper part of the upper cover. An indicator light is provided at the left front of the screen, and a key is connected to the right front of the screen. A flip cover assembly is provided at the back of the upper cover, and a socket is fixedly provided on the back of the housing body.

[0007] Further, the flip cover assembly includes a flip cover, a hinge is fixedly provided on the flip cover, the other half of the hinge is fixed to the upper cover, and a handle is fixedly provided on the flip cover.

[0008] By adopting the above technical solutions, the drive assembly, control assembly, liquid transportation assembly, pre-treatment I assembly, pre-treatment II assembly and pre-treatment III assembly inside the detector are separated by partitions, which can effectively reduce the impact of the solution inside the instrument on the circuit; the working states of the detector inside the "power supply normal", "pre-treatment in progress", "heavy metal detection in progress", "system cleaning in progress" can be directly displayed by the indicator lights; the functions of "water inlet", "water outlet" and "reset" of the internal water tank of the detector can be directly controlled by the buttons; the user can easily interact with the detector through the screen to set the "soil pre-treatment parameters", "soil detection parameters", "electrode cleaning parameters", "system cleaning parameters" and "prediction model parameters", query the previous detection data, and control the soil heavy metal detection process; the flip cover assembly can conveniently add the soil to be measured while ensuring the protection of the detector inside by the upper cover, making the use of the detector more convenient; the charging of the built-in power supply or the working power supply of the load in the detector can be directly connected to 220V AC power through the socket; the components inside the detector can be well protected by the housing.

[0009] Further, the liquid storage bottle assembly includes a bottle body, a bottle cap assembly is fixedly provided on the upper part of the bottle body, the bottle cap assembly includes a bottle cap, a first water pipe hole and an air hole are opened at the center position of the bottle cap, a water pipe passes through the first water pipe hole, and a water pipe joint is connected to the top of the water pipe.

[0010] By adopting the above technical solutions, the liquid storage bottle assembly can store a certain volume of liquid in the bottle body; the stored liquid in the liquid storage bottle assembly is greatly reduced in the risk of being polluted by the environment due to the protection of the bottle cap; the liquid storage bottle assembly transports the liquid in the bottle by inserting one end of the water pipe into the water pipe hole and connecting the other end to the corresponding water pump; the air hole on the bottle cap can well balance the internal and external atmospheric pressure when the water pump is working, facilitating the transportation of the liquid; the water pipe joint in the liquid storage bottle assembly can easily connect and disconnect the water pipe of the liquid storage bottle assembly and the water pipe extending from inside the detector, facilitating the replacement of the liquid storage bottle and the handling of the detector.

[0011] Further, the driving component includes a switching power supply. Hexagonal copper columns are fixedly arranged at four corners around the switching power supply. Three layers of fixed flat plates are fixedly arranged through the hexagonal copper columns. An internal power supply is fixedly arranged above the first layer of fixed flat plate. A step-down module is fixedly arranged at the upper right of the second layer of fixed flat plate. An ultraviolet lamp driving module is fixedly arranged directly above the second layer of fixed flat plate. An ultrasonic oscillator driving module is fixedly arranged at the upper left of the second layer of fixed flat plate. A control component is fixedly arranged at the upper part of the third layer of fixed flat plate.

[0012] Further, the control component includes a circuit board. A main control chip is arranged above the circuit board. Two ULN2003 driving enhancement chips are arranged beside the main control chip. A relay is arranged beside the ULN2003 driving enhancement chip.

[0013] By adopting the above technical solutions, the switching power supply can convert the 220V alternating current introduced by the socket into 12V direct current to supply power to the load in the detector or charge the internal power supply; the internal power supply can supply power to the device without external power supply, thereby realizing the detection of soil heavy metal concentration; the step-down module can convert the 12V DC power supply into 5V DC power supply to supply power to the main control chip, the screen and the ULN2003; through the ultraviolet lamp driving module, after inputting 12V direct current, the rated voltage required for the normal operation of the ultraviolet lamp can be output; through the ultrasonic oscillator driving module, after inputting 12V direct current, the rated voltage required for the normal operation of the ultrasonic oscillator can be output; through the cooperation of the three layers of fixed flat plates and the hexagonal copper columns, the space in the vertical direction of the device can be well utilized, and at the same time, it is convenient for device debugging and maintenance.

[0014] The main control chip, the ULN2003 driving enhancement chip and the relay are integrated on a circuit board, which greatly saves the internal space and circuit connection of the detector and is convenient for the debugging and maintenance of the detector; the main control chip can generate high and low levels, and cooperate with the ULN2003 driving enhancement chip that can enhance the driving ability of the IO port to drive the switch of the relay, thereby driving loads such as the first water pump and the first stirrer inside the soil heavy metal electrochemical detector to work regularly, can generate and measure voltage and current signals during the electrochemical detection process through AD / DA, and then process the data to obtain the soil heavy metal concentration, and can communicate with the screen through the serial port, receive instructions sent by the screen or send electrochemical data to the screen.

[0015] Further, the pre-treatment I component includes an ultrasonic oscillator. First bases are fixedly arranged on the left and rear of the ultrasonic oscillator. A first magnetic stirrer is fixedly arranged above the first base. A second support is fixedly arranged at the lower left rear of the ultrasonic oscillator.

[0016] Furthermore, the pre-treatment II component includes a water tank, a perforated plate is fixedly arranged at the bottom of the water tank, a second support component is arranged above the perforated plate, a second water pump is arranged behind the water tank, and an ultrasonic cell component is fixedly arranged above the perforated plate.

[0017] Furthermore, the second support component includes a third support column, a planar component is fixedly arranged at the upper part of the third support column, the planar component includes a first plane, and an ultrasonic cell hole and an ultraviolet photolysis cell hole are arranged on the first plane.

[0018] Furthermore, the ultrasonic cell component includes a first glass bottle, and a first magnetic stirrer is placed inside the first glass bottle.

[0019] By adopting the above technical solutions, the first magnetic stirrer can be placed on the base, and the distance from the first magnetic stirrer to the first magnetic stirrer can be well controlled, so as to achieve a good stirring effect; the ultrasonic oscillator can perform ultrasonic treatment on the soil sample to be tested in the ultrasonic cell component, which can release the heavy metals attached to the large particles in the soil and preliminarily pre-treat the soil, thereby improving the detection accuracy of the equipment; the second support column can cooperate with the ultrasonic oscillator to jointly support and fix the water tank.

[0020] Furthermore, the pre-treatment III component includes a second glass bottle, 4 ultraviolet lamps are arranged inside the second glass bottle; a second magnetic stirrer is placed inside the second glass bottle, and a third support component is fixedly arranged on the second glass bottle.

[0021] Furthermore, the third support component includes a second plane, 4 ultraviolet lamp holes are opened on the second plane, the ultraviolet lamps pass through the ultraviolet lamp holes and are fixed inside the second glass bottle, a second water pipe hole is arranged beside the ultraviolet lamp holes, a first wedge block is fixedly arranged below the second plane, and a first straight column is fixedly arranged below the second plane.

[0022] Furthermore, the liquid transportation component includes a first support component, the first support component includes 4 first support columns, and a support plane is fixedly arranged above the 4 first support columns; 7 first water pumps are fixedly arranged below the support plane.

[0023] Furthermore, the detection component includes a detection cell component, the detection cell component includes a second magnetic stirrer, a second base is arranged above the second magnetic stirrer, and a detection cell component is fixedly arranged at the upper part of the second base.

[0024] Furthermore, the detection cell component includes a third glass bottle, a working electrode, a reference electrode and a counter electrode are arranged inside the third glass bottle, a third magnetic stirrer is placed inside the third glass bottle, and a fourth support component is fixedly arranged above the third glass bottle.

[0025] Furthermore, the fourth support assembly includes a third plane, on which three electrode holes are provided. Next to the electrode holes, there are third water pipe holes. Below the third plane, a second wedge block is fixedly provided, and a second straight column is fixedly provided below the third plane; the working electrode, reference electrode, and counter electrode are fixed through the electrode holes.

[0026] By adopting the above technical solution, the second water pump can be controlled by a button to add water to the water tank (this ensures that when the ultrasonic oscillator is used to ultrasonically treat the soil in the ultrasonic cell, it will not burn out) or drain the water in the water tank (when the detector is not in use, drain the water from the water tank to avoid the influence of water leakage inside the water tank on the operation of the detector during the transportation of the detector); the orifice plate can prevent the first glass bottle in the ultrasonic cell assembly and the second glass bottle in the pretreatment III assembly from directly contacting the bottom of the water tank, thereby better realizing the ultrasonic process; the support assembly can fix and limit the ultrasonic cell assembly and the pretreatment III assembly, and thus better cooperate with the operation of the first magnetic stirrer and the ultrasonic oscillator.

[0027] Through the cooperation of the plane and the wedge block, the support assembly can be easily fixed on the second glass bottle. At the same time, the ultraviolet lamp hole on the plane can insert the ultraviolet lamp, ensuring the photolysis of organic matter in the soil solution by the ultraviolet lamp later, improving the detection accuracy of soil heavy metals. In addition, the water pipe hole on the plane can realize the addition and transfer of the solution in the ultraviolet photolysis pool. Finally, the straight column on the plane can bond the water pipe to ensure that the water pipe can extend to the bottom of the second glass bottle, ensuring the completeness of solution transfer.

[0028] By adopting the above technical solution, the second magnetic stirrer can be placed on the second base to well control the distance from the third stirrer in the detection cell assembly, thereby achieving a good stirring effect and improving the accuracy of detection data and the efficiency of electrode cleaning; the fourth support assembly in the detection cell assembly can be easily fixed on the third glass bottle through the cooperation of the third plane and the second wedge block. At the same time, the electrode holes on the third plane can insert the working electrode, reference electrode, and counter electrode to realize the electrochemical detection of heavy metals in the soil. In addition, the third water pipe hole on the plane can realize the addition and transfer of the solution in the third glass bottle. Finally, the second straight column on the third plane can bond the water pipe to ensure that the water pipe can extend to the bottom of the glass bottle, ensuring the completeness of solution transfer.

[0029] The present invention also includes a method for detecting soil using the soil heavy metal electrochemical detector integrating the soil sample pretreatment operation of the present invention, comprising the following steps:

[0030] (1) Add different types of reagents to the multiple bottle bodies of the liquid storage bottle assembly, leaving one bottle body for temporarily storing the waste liquid generated during the detection process;

[0031] (2) Connect the detector to the 220V AC power supply and turn on the switch;

[0032] (3) Open the flip cover, then add the soil to be tested into the first glass bottle inside the detector through this place, and close the flip cover;

[0033] (4) Set the relevant parameters during the electrochemical detection process by clicking on the screen, and click on the screen to start the detection;

[0034] (5) The detector detects the heavy metal concentration in the soil solution, and transmits the detection data to the screen for display and storage;

[0035] (6) After the soil heavy metal detection is completed, the detector performs automatic cleaning, and select whether to perform detection again;

[0036] (7) Query the historical detection data and analyze the data by touching the screen.

[0037] Further, in step (1), the different types of reagents include deionized water, tap water, hydrogen peroxide solution (concentration of 950 ppm), acetate buffer solution, and Bi ion solution.

[0038] Further, in step (3), the relevant parameters include deposition time, deposition potential, photolysis time, and ultrasonic time.

[0039] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0040] In the device based on the electrochemical detection technology of the present invention, the soil sample pretreatment process is integrated. By adding corresponding treatment reagents to the soil sample, driving the ultrasonic oscillator to ultrasonically treat the soil, and then driving the ultraviolet lamp to irradiate the soil solution with ultraviolet light to photolyze the organic matter in the soil and break the complexation between the organic matter and heavy metals, so that more heavy metals can be detected, effectively improving the detection degree of soil heavy metal electrochemical detection; at the same time, the high integration and high automation of the device enable the operator to only add the soil sample to be tested into the ultrasonic cell, and the remaining operations can be automatically performed by the device, effectively improving the detection efficiency of soil heavy metals and greatly liberating human resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is the front three-dimensional structural schematic diagram of the soil heavy metal electrochemical detector of the present invention after removing the housing components;

[0042] Figure 2 is the back three-dimensional structural schematic diagram of the soil heavy metal electrochemical detector of the present invention after removing the housing components;

[0043] Figure 3 is the top view of the soil heavy metal electrochemical detector of the present invention;

[0044] Figure 4 is the rear view of the soil heavy metal electrochemical detector of the present invention;

[0045] Figure 5 is the schematic cross-sectional structure diagram of the liquid storage bottle assembly of the soil heavy metal electrochemical detector of the present invention;

[0046] Figure 6 is the schematic front structure diagram of the soil heavy metal electrochemical detector after removing the housing assembly;

[0047] Figure 7 is the schematic structure diagram of the pretreatment assembly of the soil heavy metal electrochemical detector of the present invention;

[0048] Figure 8 is the schematic partial cross-sectional structure diagram of the pretreatment assembly of the soil heavy metal electrochemical detector of the present invention;

[0049] Figure 9 is the schematic structure diagram of the liquid transportation assembly of the soil heavy metal electrochemical detector of the present invention;

[0050] Figure 10 is the schematic structure diagram of the detection assembly of the soil heavy metal electrochemical detector of the present invention;

[0051] Figure 11 is the schematic partial cross-sectional structure diagram of the detection assembly of the soil heavy metal electrochemical detector of the present invention;

[0052] Figure 12 is the heavy metal peak signal diagram of the detector after using naphthol to modify the working electrode in Example 2;

[0053] Figure 13 is the heavy metal peak signal diagram of the detector under different pH acetate buffer solutions in Example 2;

[0054] Figure 14 is the heavy metal peak signal diagram of the detector under different Bi ion concentrations in Example 2;

[0055] Figure 15 is the heavy metal peak signal diagram of the detector under different stirring speeds of the second magnetic stirrer in Example 2;

[0056] Figure 16 is the heavy metal peak signal diagram of the detector under different deposition currents in Example 2;

[0057] Figure 17 is the heavy metal peak signal diagram of the detector under different deposition potentials in Example 2;

[0058] The labels in the figure are:

[0059] 1. Housing assembly;

[0060] 11. Bottom plate; 12. Partition board; 13. Housing body assembly;

[0061] 131. Indicator light; 132. Button; 133. Screen; 134. Flap assembly; 135. Socket; 136. Housing body;

[0062] 1341. Flap; 1342. Handle; 1343. Hinge;

[0063] 2. Liquid storage bottle assembly;

[0064] 21. Bottle body; 22. Bottle cap assembly; 23. Water pipe; 24. Water pipe joint;

[0065] 221. Bottle cap; 222. Air hole; 223. First water pipe hole;

[0066] 3. Driving assembly;

[0067] 31. Switching power supply; 32. Built-in power supply; 33. Step-down module; 34. UV lamp driving module; 35. Ultrasonic oscillator driving module; 36. Flat plate; 37. Hexagonal copper post;

[0068] 4. Control assembly;

[0069] 41. Main control chip; 42. ULN2003 driving enhancement chip; 43. Relay; 44. Circuit board;

[0070] 5. Liquid transportation assembly;

[0071] 51. First bracket assembly; 52. First water pump;

[0072] 511. Bracket plane; 512. First pillar;

[0073] 6. Pretreatment I assembly;

[0074] 61. Second pillar; 62. First base; 63. First magnetic stirrer; 64. Ultrasonic oscillator;

[0075] 7. Pretreatment II assembly;

[0076] 71. Water tank; 72. Orifice plate; 73. Second bracket assembly; 74. Second water pump; 75. Ultrasonic cell assembly;

[0077] 731. Third pillar; 732. Plane assembly; 751. First glass bottle; 752. First stirring bar;

[0078] 7321. Ultrasonic cell hole; 7322. UV photolysis cell hole; 7323. First plane;

[0079] 8. Pretreatment III Component;

[0080] 81. Second glass bottle; 82. Third support component; 83. Ultraviolet lamp; 84. Second magnetic stirrer;

[0081] 821. Second plane; 822. Ultraviolet lamp hole; 823. Second water pipe hole; 824. First wedge block; 825. First straight column;

[0082] 9. Detection Component;

[0083] 91. Second magnetic stirrer; 92. Second base; 93. Detection cell component;

[0084] 931. Working electrode; 932. Reference electrode; 933. Counter electrode; 934. Third glass bottle; 935. Fourth support component; 936. Third magnetic stirrer;

[0085] 9351. Third plane; 9352. Electrode hole; 9353. Third water pipe hole; 9354. Second wedge block; 9355. Second straight column. Detailed Embodiment

[0086] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0087] Embodiment 1

[0088] As Figure 1-3 shown, a soil heavy metal electrochemical detector integrating soil sample pretreatment operations according to the present invention includes a housing assembly 1, the housing assembly 1 includes a bottom plate 11 and a housing body assembly 13, the housing body assembly 13 is fixedly covered on the upper part of the bottom plate 11, a partition plate 12 is fixedly provided in the middle of the upper part of the bottom plate 11, and the partition plate 12 divides the bottom plate 11 into two parts, front and back; there are 6 liquid storage bottle assemblies 2 on the back of the housing assembly 13, a driving component 3 is provided in the front part of the bottom plate 11, a control component 4 is provided above the driving component 3, and a pretreatment I component 6, a pretreatment II component 7, and a pretreatment III component 8 are successively provided from bottom to top in the back part of the bottom plate 11. That is, the pretreatment II component 7 is provided above the pretreatment I component 6, the pretreatment III component 8 is provided above the pretreatment II component 7, and a liquid transportation component 5 is provided on the right side of the pretreatment III component 8, and a detection component 9 is provided inside the liquid transportation component 5.

[0089] Among them,

[0090] As Figure 1-4As shown in the figure, the partition 12 is fixedly connected to the bottom plate 11 by bolts, and the housing assembly 13 is fixedly connected to the bottom plate 11 by screws. The housing assembly 13 includes a housing 136 and an upper cover. A screen 133 is fixedly installed on the upper part of the upper cover by screws. An indicator light 131 is connected to the upper cover at the left front of the screen 133 by threads, and a button 132 is connected to the upper cover at the left front of the screen 133 by plastic buckles. A flip assembly 134 is provided at the rear of the upper cover, and a socket 135 is fixedly installed on the back of the housing 136 by bolts. The flip assembly 134 includes a flip 1341. A hinge 1343 is fixedly installed on the flip 1341 by screws. The other half of the hinge 1343 is connected to the upper cover of the housing 136 by screws. A handle 1342 is fixedly installed on the flip 1341 by screws.

[0091] As Figure 5 shown in the figure, the liquid storage bottle assembly 2 includes a bottle body 21. A bottle cap assembly 22 is fixedly installed on the upper part of the bottle body 21 by threads. The bottle cap assembly 22 includes a bottle cap 221. A first water pipe hole 223 is provided at the center of the bottle cap 221. An air hole 222 is provided beside the first water pipe hole 223. A water pipe 23 passes through the first water pipe hole 223. A water pipe joint 24 is connected to the top of the water pipe 23.

[0092] As Figure 6 shown in the figure, the drive assembly 3 includes a switching power supply 31 fixedly installed on the bottom plate 11 by bolts. Hexagonal copper columns 37 are fixedly installed at the four corners around the switching power supply 31 by bolts. A three-layer fixed flat plate 36 is fixedly installed through the hexagonal copper columns 37, that is, the first-layer fixed flat plate, the second-layer fixed flat plate, and the third-layer fixed flat plate from bottom to top. An internal power supply 32 is adhesively bonded above the first-layer fixed flat plate by glue. A step-down module 33 is fixedly installed at the upper right of the second-layer fixed flat plate by bolts. An ultraviolet lamp drive module 34 is fixedly installed directly above the second-layer fixed flat plate by bolts. An ultrasonic oscillator drive module 35 is fixedly installed at the upper left of the second-layer fixed flat plate by bolts. A control assembly 4 is fixedly installed on the upper part of the third-layer fixed flat plate.

[0093] The control assembly 4 includes a circuit board 44 fixedly installed on the third-layer fixed flat plate by bolts. A main control chip 41 is welded above the circuit board 44. Two ULN2003 drive enhancement chips 42 are welded beside the main control chip 41. A relay 43 is welded beside the ULN2003 drive enhancement chips 42.

[0094] As Figure 7 shown in the figure, the pre-treatment I assembly 6 includes an ultrasonic oscillator 64 installed on the bottom plate 11 by bolts. First bases 62 adhesively bonded to the bottom plate 11 by hot melt adhesive are installed on the left and rear of the ultrasonic oscillator 64. A first magnetic stirrer 63 is adhesively bonded above the first bases 62 by hot melt adhesive. A second support 61 adhesively bonded to the bottom plate 11 by hot melt adhesive is installed at the left rear of the ultrasonic oscillator 64.

[0095] As Figure 7-8 shown, the pre-treatment II component 7 includes a water tank 71 bolted above the ultrasonic oscillator 64. An ultrasonic cell assembly 75 is provided inside the water tank 71. The lower part of the water tank 71 is adhesively bonded to the second support column 61 with hot melt adhesive. A perforated plate 72 is adhesively bonded to the bottom of the water tank 71 with hot melt adhesive. Above the perforated plate 72, there is a second support assembly 73 adhesively bonded to the water tank 71 with hot melt adhesive. The second support assembly 73 includes a third support column 731. A planar assembly 732 is fixedly provided at the upper part of the third support column 731. The planar assembly 732 includes a first plane 7323. Ultrasonic cell holes 7321 and ultraviolet photolysis cell holes 7322 are provided on the first plane 7323. Behind the water tank 71, there is a second water pump 74 bolted to the housing body 136. The ultrasonic cell assembly 75 is adhesively bonded above the perforated plate 72 with hot melt adhesive. The ultrasonic cell assembly 75 includes a first glass bottle 751, and a first stirrer 752 is placed inside the first glass bottle 751. The pre-treatment III component 8 includes a second glass bottle 81 installed inside the water tank 71. Four ultraviolet lamps 83 are provided inside the second glass bottle 81. The second glass bottle 81 is limited by the ultraviolet photolysis cell holes 7322. A second stirrer 84 is placed inside the second glass bottle 81. A third support assembly 82 is adhesively bonded to the second glass bottle 81. The third support assembly 82 includes a second plane 821. Four ultraviolet lamp holes 822 are evenly formed on the second plane 821. The ultraviolet lamps 83 pass through the ultraviolet lamp holes 822 and are fixed inside the second glass bottle 81 with strong glue. A second water pipe hole 823 is provided beside the ultraviolet lamp holes 822. A first wedge-shaped block 824 is adhesively bonded to the outside of the second glass bottle 81 below the second plane 821 with strong glue. A first straight column 825 is adhesively bonded below the second plane 821 with strong glue.

[0096] As Figure 9 shown, the liquid transportation component 5 includes a first support assembly 51. The first support assembly 51 includes four first support columns 512 adhesively bonded to the bottom plate 11 with hot melt adhesive. Above the four first support columns 512, a support plane 511 is connected by screws. Three first water pumps 52 are fixedly provided below the support plane 511. By connecting the first water pumps 52 to the support plane 511, the vertical space inside the device can be well utilized.

[0097] As Figure 10-11As shown in the figure, the detection component 9 includes a detection cell component 93 installed on the bottom plate 11. The detection cell component 93 includes a second magnetic stirrer 91. Above the second magnetic stirrer 91, there is a second base 92. The upper part of the second base 92 is fixedly provided with the detection cell component 93. The detection cell component 93 includes a third glass bottle 934. Inside the third glass bottle 934, there are a working electrode 931, a reference electrode 932, and a counter electrode 933. Inside the third glass bottle 934, there is a third magnetic stir bar 936 placed. Above the third glass bottle 934, there is a fourth support component 935 adhesively bonded with hot melt adhesive. The fourth support component 935 includes a third plane 9351. On the third plane 9351, three electrode holes 9352 are evenly distributed. Next to the electrode holes 9352, there is a third water pipe hole 9353. Below the third plane 9351, there is a second wedge block 9354 adhesively bonded with strong glue. Below the third plane 9351, there is a second straight column 9355 adhesively bonded with strong glue. The working electrode 931, the reference electrode 932, and the counter electrode 933 are fixed through the electrode holes 9352.

[0098] The drive component 3, the control component 4, the liquid transportation component 5, the pretreatment I component 6, the pretreatment II component 7, and the pretreatment III component 8 inside the soil heavy metal electrochemistry detector are separated by a partition 12, which can effectively reduce the influence of the solution inside the detector on the circuit. The working states of the equipment inside the detector, such as "power supply normal", "pretreatment in progress", "heavy metal detection in progress", and "system cleaning in progress", can be directly displayed through the indicator light 131. The functions of "water inlet", "water outlet", and "reset" of the internal water tank 71 of the detector can be directly controlled through the button 132. The user can easily perform human-computer interaction with the soil heavy metal electrochemistry detector through the screen 133 to set "soil pretreatment parameters", "soil detection parameters", "electrode cleaning parameters", "system cleaning parameters", and "prediction model parameters", query the previous detection data, and control the soil heavy metal detection process. The flip cover 1341 component on the upper cover of the detector can, while ensuring the protection of the detector inside by the shell body 136, easily add the soil to be measured, making the use of the detector more convenient.

[0099] The charging or load working power supply of the built-in power supply 322 in the soil heavy metal electrochemistry detector can be directly connected to 220V alternating current through the socket 135. The components inside the detector can be well protected by the shell body 136.

[0100] The liquid storage bottle assembly 2 can store a certain volume of liquid in the bottle body 21; the liquid stored in the liquid storage bottle assembly 2 is greatly protected from environmental pollution due to the protection of the bottle cap 22; the liquid storage bottle assembly 2 realizes the transportation of the liquid in the bottle by inserting one end of a water pipe into the first water pipe hole 223 and connecting the other end to the corresponding water pump 42; the air hole 222 on the bottle cap can well balance the internal and external atmospheric pressures when the water pump 42 is working, facilitating the transportation of the liquid; the water pipe joint 24 in the liquid storage bottle assembly 2 can easily realize the connection and disconnection between the water pipe 23 of the liquid storage bottle assembly 2 and the water pipe 23 extending from the inside of the detector, facilitating the replacement of the liquid storage bottle and the handling of the detector.

[0101] The switching power supply 31 can convert the 220V alternating current introduced by the socket 135 into 12V direct current to supply power to the loads in the detector or charge the built-in power supply 32; through the built-in power supply 32, the detector can be powered without external power supply, and then the detection of soil heavy metal concentration can be realized; the buck module 33 can convert the 12V DC power supply into a 5V DC power supply to supply power to the main control chip 41, the screen 133 and the ULN2003 drive enhancement chip 42; through the ultraviolet lamp drive module 34, after inputting 12V DC power, the rated voltage required for the normal operation of the ultraviolet lamp 83 can be output; through the ultrasonic oscillator drive module 35, after inputting 12V DC power, the rated voltage required for the normal operation of the ultrasonic oscillator 64 can be output; through the cooperation of the three-layer fixed flat plate 36 and the hexagonal copper column 37, the space in the vertical direction of the detector can be well utilized, and at the same time, it is convenient for the debugging and maintenance of the detector.

[0102] The main control chip 41, the ULN2003 drive enhancement chip 42 and the relay 43 are integrated on a circuit board 44, greatly saving the space and circuit connection inside the detector and facilitating the debugging and maintenance of the detector; the main control chip 41 can drive the switch of the relay 43 by generating high and low levels and cooperating with the ULN2003 drive enhancement chip 42 that can enhance the driving ability of the IO port, and then drive the loads such as the first water pump 52 and the first stirrer 63 inside the soil heavy metal electrochemical detector to work regularly. It can generate and measure the voltage and current signals during the electrochemical detection process through AD / DA, and then process the data to obtain the soil heavy metal concentration. It can communicate with the screen 133 through the serial port, receive the instructions sent by the screen 133 or send the electrochemical data to the screen.

[0103] The first magnetic stirrer 63 can be placed on the first base 62 to well control the distance from the first stirring bar 752, thereby achieving a good stirring effect; the ultrasonic oscillator 64 can perform ultrasonic treatment on the soil sample to be tested in the ultrasonic cell assembly 75, which can release the heavy metals attached to the large particles in the soil and preliminarily pretreat the soil, thereby improving the detection accuracy of the detector; the second support column 61 can cooperate with the ultrasonic oscillator 64 to jointly support and fix the water tank 71.

[0104] The second water pump 74 can be controlled by the button 132 to add water to the water tank 71 (this ensures that the ultrasonic oscillator 64 will not burn out when performing ultrasonic treatment on the soil in the ultrasonic cell) or drain the water in the water tank 71 (when the detector is not in use, drain the water in the water tank to avoid the influence of water leakage inside the water tank on the detector during the transportation of the detector); the orifice plate 72 can prevent the first glass bottle 751 in the ultrasonic cell assembly 75 and the second glass bottle 81 in the pretreatment III assembly 8 from directly contacting the bottom of the water tank 71, thereby better realizing the ultrasonic process; the support assembly 82 can fix and limit the ultrasonic cell assembly 75 and the pretreatment III assembly 8, thereby better cooperating with the work of the first magnetic stirrer 63 and the ultrasonic oscillator 64.

[0105] Through the cooperation of the plane 821 and the wedge block 824, the support assembly 82 can be easily fixed on the second glass bottle 81. At the same time, the ultraviolet lamp hole 822 on the plane 821 can insert the ultraviolet lamp 83, ensuring the photolysis of organic matter in the soil solution by the ultraviolet lamp 83 later and improving the detection accuracy of soil heavy metals. In addition, the water pipe hole 823 on the plane 821 can realize the addition and transfer of the solution in the ultraviolet photolysis pool. Finally, the straight column 825 on the plane 821 can ensure that the water pipe 23 can extend to the bottom of the second glass bottle 81 by bonding the water pipe 23, ensuring the completeness of the solution transfer.

[0106] The second magnetic stirrer 91 can be placed on the second base 92 to well control the distance from the third magnetic stir bar 936 in the detection cell assembly 93, thereby achieving a good stirring effect, improving the accuracy of detection data and the efficiency of electrode cleaning; the fourth support assembly 935 in the detection cell assembly 93 can be easily fixed on the third glass bottle 934 through the cooperation of the third plane 9351 and the second wedge block 9354. At the same time, the electrode holes 9352 on the third plane 9351 can insert the working electrode 931, the reference electrode 932 and the counter electrode 933 to realize the electrochemical detection of heavy metals in the soil. In addition, the third water pipe hole 9353 on the plane can realize the addition and transfer of the solution in the third glass bottle 934. Finally, the second straight column 9355 on the third plane 9351 can ensure that the water pipe can extend to the bottom of the glass bottle by bonding the water pipe, ensuring the completeness of the solution transfer.

[0107] As Figure 6 , Figure 7 , Figure 10 shown, the working process of the detector includes: turning on the switch to start the detector, and the detector enters the initial interface. The user touches any position on the screen, and the detector enters the menu interface. The working process of the detector can be mainly divided into the following stages: parameter setting stage, water pipe 23 filling stage, data storage selection stage, soil pretreatment stage, electrode activation stage, detection stage, electrode cleaning stage, system cleaning stage and data query stage;

[0108] Parameter setting stage: In this stage, the user can set all types of parameters in the detector, such as the ultraviolet photolysis time, soil ultrasonic time, etc.;

[0109] Water pipe filling stage: In this stage, the detector will operate according to the specified parameters written in the pre-programmed program, turn on the first water pump 52 to make the reagent fill the water pipe 23, and discharge the reagent that overflows from the water pipe 23 and flows into the ultrasonic cell assembly 75 and the pretreatment III assembly 8 from the detector. The purpose of this stage is to make the addition of the reagent more accurate, thereby ensuring the accuracy of the final detection;

[0110] Data storage selection stage: In this stage, the user can pre-select the file name and file location for storing the detection data, which helps the user better manage the detection data;

[0111] Soil pretreatment stage: In this stage, the detector will turn on the first magnetic stirrer 63 according to the parameters set by the user, which is beneficial to the more thorough mixing of the soil with the reagent. The ultrasonic oscillator 64 is turned on to perform ultrasonic treatment on the soil to be tested, which is beneficial to the more thorough mixing of the soil with the reagent. At the same time, some heavy metals originally attached to the soil particles enter the reagent, improving the accuracy of the final soil heavy metal detection. The ultraviolet lamp 83 is turned on to perform ultraviolet photolysis on the soil to be tested, breaking the complexation between heavy metals and humus in the soil, making the organic heavy metals that could not be detected by the detector originally become free heavy metals and be able to be detected, further improving the detection accuracy of the detector;

[0112] Electrode activation stage: In this stage, the main control chip 41 will apply a deposition potential for a certain period of time and a cleaning potential for a certain period of time on the working electrode 931 in sequence according to the parameters set by the user. By this step, the polarization of the working electrode is achieved, which is beneficial to improving the detection accuracy and stability during the formal detection;

[0113] Detection stage: In this stage, the main control chip 41 will apply a deposition potential for a certain period of time on the working electrode 931 according to the parameters set by the user. At the same time, the second magnetic stirrer 91 is turned on to cooperate with the heavy metals in the solution to deposit on the working electrode. After the deposition process is completed, the second magnetic stirrer 91 is turned off. After the solution stands for 12 s, the main control chip 41 will apply a scanning potential on the working electrode 931 according to the parameters, and at the same time detect the oxidation current flowing through the working electrode 931. After all the detection data are obtained, the main control chip 41 will finally obtain the detection result of the soil heavy metal according to the peak recognition algorithm and the filtering algorithm, combined with the prediction model, and send the detection result and the detection data to the screen 133;

[0114] Electrode cleaning stage: In this stage, the main control chip 41 will apply a cleaning potential for a certain period of time on the working electrode 931 to completely oxidize the residual heavy metals on the working electrode into the solution, avoiding affecting the soil heavy metal detection result in the future;

[0115] System cleaning stage: In this stage, the first water pump 52 inside the detector will start to work, and the detector is cleaned with deionized water to prepare for the next measurement;

[0116] Data query stage: In this stage, the user can query the previous detection results and detection data, which is beneficial to the user's analysis of the detection results.

[0117] Working principle: In the detector based on electrochemical detection technology, the pre-treatment process of soil samples is integrated. By adding corresponding treatment reagents to the soil samples and driving the ultrasonic oscillator to perform ultrasonic treatment on the soil, then driving the ultraviolet lamp 83 to irradiate the soil solution with ultraviolet light to photolyze the organic matter in the soil and break the complexation between the organic matter and heavy metals, so that more heavy metals can be detected, effectively improving the detection degree of electrochemical detection of soil heavy metals. At the same time, the high integration and high automation of the detector enable the operator to only add the soil samples to be tested into the ultrasonic cell, and the remaining operations can be automatically carried out by the detector, effectively improving the detection efficiency of soil heavy metals and greatly liberating human resources.

[0118] Finally, it should be noted that: In the description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "vertical", "upper", "lower", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0119] In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0120] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0121] The above-mentioned electrochemical detector for soil heavy metals detects heavy metals in soil, and the specific detection process includes the following steps:

[0122] (1) Add different types of reagents to the 5 bottle bodies 21 from left to right of the liquid storage bottle assembly 2, which are deionized water, tap water, hydrogen peroxide solution (concentration of 950 ppm), acetate buffer solution, and Bi ion solution respectively. The rightmost bottle body 21 is used to temporarily store the waste liquid generated during the detection process.

[0123] (2) Insert the working electrode 931, reference electrode 932 and counter electrode 933 into the electrode holes 9352 on the third plane 9351.

[0124] (3) Connect the detector to a 220V AC power supply and turn on the switch.

[0125] (4) Open the flip cover 1341 on the upper part of the device through the handle 1342, and then add the soil to be detected into the first glass bottle 751 inside the detector through this place. After the addition is completed, the flip cover 1341 can be closed.

[0126] (5) Through the touch screen 133, relevant parameters in the electrochemical detection process can be set, including deposition time, deposition potential, photolysis time, and ultrasonic time. After the parameter setting is completed, the screen 133 can be clicked to officially start the detection.

[0127] (6) First, the detector will add 18 mL of acetate buffer solution in the bottle body 21 into the first glass bottle 751 through the first water pump 52. Then, the first magnetic stirrer 63 starts to stir. After sufficient stirring, the ultrasonic oscillator 64 starts to complete the ultrasonic treatment of the soil solution according to the set ultrasonic time.

[0128] (7) After the ultrasonic treatment of the soil is completed, the first water pump 52 will transfer all the soil solution in the first glass bottle 751 to the second glass bottle 81, and then add 1 mL of hydrogen peroxide solution in the bottle body 21 to it. At the same time, the first magnetic stirrer 63 starts to stir. After sufficient mixing, the ultraviolet lamp 83 starts to complete the photolysis of the soil solution according to the set photolysis time.

[0129] (8) After the photolysis of the soil is completed, the first water pump 52 will transfer all the soil solution in the second glass bottle 81 to the third glass bottle 934, and then add 1 mL of Bi ion solution in the bottle body 21 to it. At the same time, the second magnetic stirrer 91 stirs. After sufficient mixing, the main control chip 41 starts to detect the heavy metal concentration in the soil solution through the working electrode 931, reference electrode 932 and counter electrode 933, and transmits the detection data to the screen 133 for display and storage.

[0130] (9) After the heavy metal detection of the soil is completed, electrode cleaning starts. The main control chip 41 removes the heavy metals remaining on the working electrode 931 by applying a potential.

[0131] (10) After the cleaning is completed, you can choose whether to perform the detection again. If you choose to detect again, the detector will repeat the previous steps to detect the heavy metals in the soil; if you choose not to detect again, the detector will automatically clean the inside of the device. After the cleaning is completed, the detection process ends.

[0132] (11) By touching the screen 133, historical detection data can be queried and analyzed.

[0133] Example 2

[0134] Using the soil heavy metal electrochemical detector described in Example 1, i.e., the detection process, to detect heavy metals in the soil, and optimizing the relevant parameters in the detector. The parts that can be optimized in the detector include whether to modify the electrode with naphthol, pH value, Bi ion concentration, stirring rate, deposition time, and deposition potential. In this example, the simulated soil to be measured is 90 μL of 10 ppm Cd ion standard solution and 90 μL of 100 ppm Pb ion standard solution.

[0135] 1. Whether to modify the working electrode 931 with naphthol:

[0136] Before inserting the working electrode 931 into the detector, use 10 μL of 2.5% naphthol solution to evenly coat its surface, then use a red light to dry the working electrode 931. After the naphthol on the working electrode is completely dry, insert the working electrode 931 into the detector. Use acetate buffer solution with pH 4.5, Bi ion concentration of 7 ppm, the rotation speed of the second magnetic stirrer 91 is 1500 rpm, set the deposition time to 200 s, deposition potential to -1200 mV, photolysis time to 900 s, and ultrasonic time to 300 s. The rest of the detection process of the detector remains the same as in Example 1. Detect the parameters in the solution multiple times until the detection data is stable. Plot the graph with each detection value. The results Figure 12 are shown.

[0137] After analyzing the data, it is found that with the modification of the working electrode with naphthol, the detection data begins to gradually stabilize after 12 detections. The heavy metal peak signals of the detector are Cd at 0 μA, Pb at 11.59 μA; Cd at 0 μA, Pb at 21.43 μA; Cd at 1.5 μA, Pb at 31.01 μA; Cd at 5 μA, Pb at 34.5 μA; Cd at 7.25 μA, Pb at 37.48 μA; Cd at 10.47 μA, Pb at 38.07 μA; Cd at 13.79 μA, Pb at 39.83 μA; Cd at 15.14 μA, Pb at 40.61 μA; Cd at 17.70 μA, Pb at 40.16 μA; Cd at 20.08 μA, Pb at 41.62 μA; Cd at 20.65 μA, Pb at 41.70 μA; Cd at 22.14 μA, Pb at 42.03 μA. This is not conducive to the rapid detection of soil heavy metals and is contrary to the usage positioning of this equipment. Therefore, the working electrode 931 inside the detector does not use naphthol modification for auxiliary detection.

[0138] 2. pH value optimization:

[0139] Prepare acetate buffer solutions with pH values of 3.5, 4.0, 4.5, 5.0, and 5.5, and connect the acetate buffer solutions with different pH values to the detector respectively. The remaining detection processes of the detector are the same as those in Example 1 of this embodiment. Three groups of data are obtained corresponding to each acetate buffer solution with a different pH value, and the average values are plotted. The results Figure 13 are shown as follows.

[0140] It can be seen from the data analysis of Figure 13 that when using acetate buffer solutions with pH values ranging from 3.5 to 5.5, the heavy metal peak signals of the detector are: for Cd, they are 22.06 μA, 43.32 μA, 49.53 μA, 36.61 μA, and 24.40 μA respectively; for Pb, they are 24.09 μA, 54.11 μA, 63.54 μA, 41.60 μA, and 26.34 μA respectively. Among them, when the pH is 4.5, the heavy metal peak signal is the strongest. Therefore, the detector finally selects the acetate buffer solution with this pH value for detection.

[0141] 3. Concentration of Bi ions:

[0142] Prepare Bi ion solutions with concentrations of 4, 6, 8, 10, and 12 ppm, with the pH of the acetate buffer solution being 4.5. Connect the different Bi ion solutions to the detector respectively. The remaining detection processes of the detector are the same as those in Example 1 of this embodiment. Three groups of data are obtained corresponding to each Bi ion solution with a different concentration, and the average values are plotted. The results Figure 14 are shown as follows.

[0143] It can be seen from the data analysis of Figure 14 that when using Bi ion solutions with concentrations ranging from 4 to 12 ppm for detection, the heavy metal peak signals of the detector are: for Cd, they are 47.07 μA, 44.31 μA, 49.53 μA, 44.12 μA, 41.98 μA, and 38.77 μA respectively; for Pb, they are 58.97 μA, 63.66 μA, 63.54 μA, 60.37 μA, 62.56 μA, and 64.29 μA respectively. Among them, when the Bi ion concentration is 7 ppm, the heavy metal peak signal is the strongest. Therefore, the detector finally selects the Bi ion solution with this concentration for detection.

[0144] 4. Stirring rate:

[0145] Set the stirring rates of the second magnetic stirrer 91 to 1300, 1500, 1700, and 1900 rpm in sequence, the pH of the acetate buffer solution is 4.5, and the Bi ion concentration is 7 ppm. The remaining detection processes of the detector are the same as those in Example 1. Three groups of data are obtained for each stirring rate and plotted as an average value. The results are as Figure 15 shown.

[0146] From the Figure 15 data analysis, it can be seen that when the detector is tested at the rotational speeds of 1300 - 1900 rpm of the magnetic stirrer 91, the heavy metal peak signals of the detector are 39.57 μA for Cd and 58.23 μA for Pb; 33.14 μA for Cd and 62.01 μA for Pb; 36.47 μA for Cd and 66.64 μA for Pb; 34.09 μA for Cd and 64.15 μA for Pb. Among them, when the rotational speed of the second magnetic stirrer 91 is 1700 rpm, the heavy metal peak signal is the strongest. Therefore, the equipment finally selects to perform the detection at this rotational speed.

[0147] 5. Deposition time:

[0148] Set the deposition times to 180, 190, 200, 210, and 220 s in sequence. The pH of the acetate buffer solution is 4.5, the Bi ion concentration is 7 ppm, the rotational speed of the second magnetic stirrer 91 is 1700 rpm, and the remaining detection processes of the detector are the same as those in Example 1. Three groups of data are obtained for each deposition time and plotted as an average value. The results are as Figure 16 shown.

[0149] From the Figure 16 data analysis, it can be seen that when the deposition time is 180 - 220 s, the heavy metal peak signals of the detector are 31.59 μA for Cd and 64.92 μA for Pb; 31.74 μA for Cd and 63.30 μA for Pb; 36.47 μA for Cd and 66.64 μA for Pb; 33.45 μA for Cd and 62.76 μA for Pb; 33.75 μA for Cd and 62.02 μA for Pb. Among them, when the deposition time is 200 s, the heavy metal peak signal is the strongest. Therefore, the equipment finally selects to perform the detection through this deposition time.

[0150] 6. Deposition potential:

[0151] Set the deposition potentials to -1400, -1300, -1200, -1100, and -1000 mV in sequence. The pH of the acetate buffer solution is 4.5, the Bi ion concentration is 7 ppm, the rotational speed of the second magnetic stirrer 91 is 1700 rpm, the deposition time is 200 s, and the remaining detection processes of the detector are the same as those in Example 1. Three groups of data are obtained for each deposition potential and plotted as an average value. The results are asFigure 17 as shown

[0152] Through the analysis of Figure 17 data, it can be seen that when the deposition potential is -1400 to -1000 mV, the peak signals of heavy metals detected by the detector are 31.04 μA for Cd and 63.94 μA for Pb; 29.13 μA for Cd and 62.72 μA for Pb; 36.47 μA for Cd and 66.64 μA for Pb; 27.68 μA for Cd and 59.94 μA for Pb; 24.81 μA for Cd and 54.07 μA for Pb. Among them, when the deposition potential is -1200 mV, the peak signal of heavy metals is the strongest. Therefore, the device finally selects to perform detection through this deposition potential.

[0153] In summary, when the pH of the acetate buffer solution of the detector is 4.5, the concentration of Bi ions is 7 ppm, the rotation speed of the second magnetic stirrer 91 is 1700 rpm, the deposition time is 200 s, and the deposition potential is -1200 mV, the signal of heavy metal value is the strongest and the detection effect is the best.

[0154] Comparative experiment

[0155] The detection effect of the device was compared with that of manual detection (manual pretreatment of soil alone). The specific operations are as follows:

[0156] 1. Preparation of soil to be tested: Take 10 g of the soil sample to be tested, sieve the soil sample through a soil sieve with a pore size of 0.075 mm, then dry the sieved soil in an oven at 100 °C for 10 min, and then mix the obtained soil evenly.

[0157] 2. Detection by the device of the present invention:

[0158] Take two 1-g soil samples to be tested and add them to the first glass bottle 751 for detection respectively. The rest of the detection process of the detector adopts the optimal situation in Example 2 to obtain the detection results, and the average value is shown in Table 1.

[0159] 3. National standard detection:

[0160] Divide the remaining soil samples to be tested into two parts and detect them according to the national environmental protection standard HJ 781-2016 "Determination of 22 Metal Elements in Solid Wastes - Inductively Coupled Plasma Optical Emission Spectrometry". The detection instrument is ICP-OES / MS (model is Aglient 7800 (MS) of the United States), and the detection results are obtained. The average value is shown in Table 1.

[0161] Table 1 Comparison of detection effects between the present invention and national standard

[0162]

[0163] It can be seen from the analysis of the data in Table 1 that the detection results of heavy metals in soil by the detector of the present invention have a small error compared with the national standard detection results, which further indicates that the present invention has good detection accuracy. At the same time, the present invention realizes automatic detection and is suitable for large-scale rapid detection.

Claims

1. An electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations, comprising a housing assembly (1), characterized in that, The housing assembly (1) includes a bottom plate (11) and a housing body assembly (13) fixedly covering the upper part of the bottom plate (11). A partition plate (12) is fixedly provided in the middle of the upper part of the bottom plate (11), and the partition plate (12) divides the bottom plate (11) into front and rear parts; a plurality of liquid storage bottle assemblies (2) are provided on the back of the housing body assembly (13), a driving assembly (3) is provided in the front part of the bottom plate (11), a control assembly (4) is provided above the driving assembly (3), and a pre-treatment I assembly (6), a pre-treatment II assembly (7), and a pre-treatment III assembly (8) are successively provided from bottom to top in the rear part of the bottom plate (11); a liquid transportation assembly (5) is provided to the right of the pre-treatment III assembly (8), and a detection assembly (9) is provided inside the liquid transportation assembly (5). Among them, the pre-treatment I assembly (6) includes an ultrasonic oscillator (64). First bases (62) are fixedly provided on the left and rear sides of the ultrasonic oscillator (64), a first magnetic stirrer (63) is fixedly provided above the first bases (62), and a second support column (61) is fixedly provided at the left rear of the ultrasonic oscillator (64); the pre-treatment II assembly (7) includes a water tank (71). A perforated plate (72) is fixedly provided at the bottom of the water tank (71), a second support assembly (73) is provided above the perforated plate (72), a second water pump (74) is provided behind the water tank (71), and an ultrasonic bath assembly (75) is fixedly provided above the perforated plate (72); the pre-treatment III assembly (8) includes a second glass bottle (81). Four ultraviolet lamps (83) are provided inside the second glass bottle (81); a second magnetic stirrer (84) is placed inside the second glass bottle (81), and a third support assembly (82) is fixedly provided on the second glass bottle (81).

2. The electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations according to claim 1, characterized in that, The housing body assembly (13) includes a housing body (136) and an upper cover. A screen (133) is fixedly provided on the upper part of the upper cover. An indicator light (131) is provided at the left front of the screen (133), a key (132) is connected at the right front of the screen (133), a flip assembly is provided behind the upper cover, and a socket (135) is fixedly provided on the back of the housing body (136).

3. The electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations according to claim 1, characterized in that, The liquid storage bottle assembly (2) includes a bottle body (21). A bottle cap assembly (22) is fixedly provided on the upper part of the bottle body (21). The bottle cap assembly (22) includes a bottle cap (221). A first water pipe hole (223) and an air hole (222) are opened at the central position of the bottle cap (221). A water pipe (23) passes through the first water pipe hole (223), and a water pipe joint (24) is connected to the top of the water pipe (23).

4. The electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations according to claim 1, characterized in that, The driving component (3) includes a switching power supply (31). Four corners around the switching power supply (31) are fixedly provided with hexagonal copper columns (37). Through the hexagonal copper columns (37), three layers of fixed flat plates (36) are fixedly provided. An internal power supply (32) is fixedly provided above the first layer of fixed flat plate. A step-down module (33) is fixedly provided at the upper right of the second layer of fixed flat plate. An ultraviolet lamp driving module (34) is fixedly provided directly above the second layer of fixed flat plate. An ultrasonic oscillator driving module (35) is fixedly provided at the upper left of the second layer of fixed flat plate. A control component (4) is fixedly provided at the upper part of the third layer of fixed flat plate.

5. The electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations according to claim 1, characterized in that, The control component (4) includes a circuit board (44). Above the circuit board (44), there is a main control chip (41). Next to the main control chip (41), there are two ULN2003 driving enhancement chips (42). Next to the ULN2003 driving enhancement chips (42), there is a relay (43).

6. The electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations according to claim 1, characterized in that, The liquid transportation component (5) includes a first bracket component (51). The first bracket component (51) includes four first support columns (512). Above the four first support columns (512), there is a bracket plane (511) fixedly provided. Below the bracket plane (511), three first water pumps (52) are fixedly provided.

7. The electrochemical detector for heavy metals in soil integrating soil sample pretreatment operations according to any one of claims 1-6, characterized in that, The detection component (9) includes a second magnetic stirrer (91). Above the second magnetic stirrer (91), there is a second base (92). At the upper part of the second base (92), a detection cell component (93) is fixedly provided.

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