Device and method for treating heavy metal contaminated soil by adopting natural mineral modified biochar

Abstract

The invention discloses a device and method for treating heavy metal contaminated soil through natural mineral modified biochar, and belongs to the technical field of heavy metal contaminated soil remediation and treatment. The device comprises a treatment box, a pretreatment assembly, a separation assembly and an adsorption assembly, the pretreatment assembly comprises a crushing box, a crushing roller and a crushing motor; the separation assembly comprises a conical mesh screen, a rotating disc, a scraping plate and a separation motor; the adsorption assembly comprises an adsorption barrel, an isolation net barrel, an exhaust fan and an ultrasonic generator; the device is reasonable in structural design, the smashed heavy metal contaminated soil is heated, organic arsenic, organic cadmium and organic mercury in the heavy metal contaminated soil are converted into gaseous states, at the moment, the gaseous organic arsenic, organic cadmium and organic mercury in the heavy metal contaminated soil are extracted through the exhaust fan, and the heavy metal contaminated soil is purified. The soil is adsorbed when passing through the natural mineral modified charcoal, so that the treatment of the heavy metal contaminated soil is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of heavy metal contaminated soil remediation and treatment, and in particular to a device and method for treating heavy metal contaminated soil by using natural mineral modified biochar. Background Art

[0002] Wastewater containing heavy metals produced by industrial smelting, electroplating, fuel, etc. enters the soil through various pathways, causing soil heavy metal pollution, especially soil heavy metal pollution in agricultural land, resulting in excessive heavy metal content in agricultural products. Once heavy metals enter the food chain, they will accumulate in organisms, posing a potential threat to human health. Moreover, heavy metal enrichment will also lead to reduced yield and quality of crops. Therefore, the control of soil heavy metal pollution has become an issue that needs to be resolved.

[0003] Existing methods for remediating soil heavy metal pollution mainly include physical soil replacement, chemical passivation and plant absorption. The physical and chemical methods have complex operating techniques and high economic costs. The physical soil replacement method only solves short-term problems, and the heavy metals in the contaminated soil still need to be solved after soil replacement. The chemical passivation method only converts heavy metals into a state that is difficult for plants to use, but heavy metals still remain in the soil, and the problem of soil heavy metal pollution is not fundamentally solved. Although plant restoration is low-cost, the hyperaccumulator plants discovered so far are rarely used in the field, making it difficult to solve large-scale pollution restoration. In addition, due to the characteristics of low biomass and slow growth, the restoration efficiency is low. Summary of the invention

[0004] In view of the above-mentioned technical problems, the present invention provides a device and method for treating heavy metal contaminated soil by using natural mineral modified biochar.

[0005] The technical solution of the present invention is: a device for treating heavy metal contaminated soil by using natural mineral modified biochar, comprising a treatment box, a pretreatment component, a separation component and an adsorption component;

[0006] The pre-processing assembly includes a crushing box arranged at the top of the processing box, a crushing roller clamped inside the crushing box, and a crushing motor providing power to the crushing roller;

[0007] The separation assembly includes a conical mesh screen arranged inside the processing box, a rotating disk rotatably connected to the upper end surface of the conical mesh screen, a scraper plate arranged in the circumference of the rotating disk, and a separation motor providing power to the rotating disk;

[0008] The adsorption assembly includes an adsorption cylinder arranged at the bottom of the treatment box, an isolation net cylinder clamped inside the adsorption cylinder, an exhaust fan and an ultrasonic generator arranged at the bottom of the treatment box; a guide cone is arranged at the top of the adsorption cylinder, and an air intake pipe is arranged on the outer wall of the adsorption cylinder; natural mineral modified biochar particles are filled between the isolation net cylinder and the adsorption cylinder; an exhaust joint connected to the exhaust fan is arranged at the bottom of the treatment box; a magnetron connected to the ultrasonic generator is arranged on the inner wall of the treatment box.

[0009] Furthermore, the method for preparing natural mineral modified biochar particles comprises the following steps:

[0010] S1. In an anaerobic state, the agricultural straw is pyrolyzed and carbonized at a temperature of 400 to 600°C for 1 to 2 hours to obtain biochar;

[0011] S2, crushing the bentonite and sieving it through a 120-mesh sieve for standby use; mixing sodium sulfide and the sieved bentonite in a mass ratio of 1 to 10:100, and placing it at a temperature of 100 to 150° C. for 60 to 170 minutes for vulcanization modification to obtain vulcanized modified bentonite;

[0012] S3, the sulfide modified bentonite obtained in step S2 and the biochar obtained in step S1 are stirred and evenly mixed in a mass ratio of 1:3, and then placed in a hydrothermal carbonization furnace, and hydrothermally carbonized at a temperature of 300-650° C. for 1-3 hours; after the treatment is completed, it is naturally cooled to room temperature to obtain natural mineral modified biochar particles with a particle size of 3-7 mm;

[0013] Description: Biochar and natural minerals are both porous materials. After the two are combined, they can play their respective advantages, make up for their respective deficiencies, and promote each other. Biochar is stronger than natural minerals in degrading COD and phosphorus, but natural minerals are stronger than biochar in adsorbing heavy metals. The natural mineral modified biochar prepared by the present invention can adsorb and fix gaseous organic arsenic, organic cadmium, and organic mercury in the soil, and will not cause secondary pollution to the soil.

[0014] Furthermore, an integrated sleeve is provided inside the processing box and at the upper end where the conical mesh screen is connected to the processing box; one end of each scraper plate is respectively slidably engaged with the integrated sleeve, and the other end is respectively slidably engaged with the rotating disk, and both ends of the upper end surface of the scraper plate are provided with compression springs that abut against the integrated sleeve and the rotating disk respectively;

[0015] Description: By slidingly engaging the two ends of the scraper plate with the integrated sleeve and the rotating disk respectively, the scraper plate is always in close contact with the upper end surface of the conical mesh screen under the action of the compression spring, which can prevent soil particles from accumulating on the surface of the conical mesh screen and causing blockage.

[0016] Furthermore, an equipment box is arranged at the upper end of the adsorption cylinder, and the guide cone is connected to the equipment box; a sealing disk is sleeved on the outside of the equipment box, and a plurality of sector plates are rotatably clamped on the sealing disk; each sector plate is rotatably clamped with the sealing disk through a rotating shaft, each rotating shaft passes through the equipment box, and each rotating shaft is sleeved with a connecting gear; a push disk is arranged above the equipment box, and a rack that passes through the equipment box and is meshed with the connecting gear at the corresponding position is arranged on the lower bottom surface of the push disk and at positions corresponding to each connecting gear; a driving motor is arranged on the top of the equipment box, and a driving screw that passes through the equipment box and is threadedly connected to the pushing disk is arranged at the output end of the driving motor;

[0017] Description: The driving motor is used to drive the driving screw to rotate, so that the push plate drives each rack to move downward along the equipment box under the action of the driving screw. During the movement of the rack, the connecting gear and the fan plate are driven to rotate at the same time to seal the sealing plate, which is beneficial to reduce the heat loss when the heavy metal contaminated soil is heated, and has a promoting effect on reducing the energy consumption of the device.

[0018] Furthermore, a linkage ring is sleeved inside the equipment box, and connection blocks penetrating the equipment box and connected to the linkage ring are arranged at the circumference of the sealing disk and at positions corresponding to the rotating shaft; the connection blocks are slidably engaged with the equipment box, and the rotating shaft penetrates the connection blocks at corresponding positions; and limited seats are arranged on the bottom surface of the linkage ring and at positions corresponding to the positions of each rack;

[0019] Description: When the sealing disk is in a sealed state, each rack is respectively in contact with the limit seat at the corresponding position. At this time, the driving motor continues to drive the push disk to move downward. At this time, each rack squeezes the limit seat at the corresponding position, and the linkage ring drives the sealing disk to move downward along the adsorption cylinder through the connecting block, thereby compacting the heated heavy metal contaminated soil, which is beneficial to improve the adsorption and fixation efficiency of gaseous organic arsenic, organic cadmium and organic mercury in the soil.

[0020] Furthermore, a guide column movably plugged with the rack is provided on the bottom surface of the limit seat;

[0021] Note: By setting the guide column, the positioning reliability of the rack and the limit seat can be improved, and it is also beneficial to improve the meshing stability of the rack and the connecting gear.

[0022] Furthermore, a bracket is provided at the lower end of the treatment box; a plurality of filling net cylinders are equidistantly distributed between the isolation net cylinder and the adsorption cylinder; the lower end of each filling net cylinder penetrates the treatment box and is movably connected to the treatment box by bolts; each filling net cylinder is connected to each suction pipe one by one; a conversion disk is provided at the bottom of the bracket, and an electric push rod capable of being clamped with the bottom end of any filling net cylinder is provided on the upper end surface of the conversion disk;

[0023] Description: By loading natural mineral modified biochar particles into each filling net cylinder, and movably connecting each filling net cylinder with a processing box, each filling net cylinder can be easily taken out from the processing box by an electric push rod, thereby facilitating the replacement of the natural mineral modified biochar particles inside the filling net cylinder.

[0024] Furthermore, a closing plate is slidably engaged with the inner wall of the adsorption cylinder and corresponding to the position of each suction pipe; a plug-in rod slidably engaged with the adsorption cylinder is provided on the closing plate, and a return spring abutting against the adsorption cylinder is provided at the top of the plug-in rod; a shifting block capable of movably engaging with the closing plate is provided on the outer wall of the filling net cylinder;

[0025] Description: When the natural mineral modified biochar particles inside a filling net cylinder need to be replaced and the filling net cylinder is taken out, the corresponding shifting block is separated from the closing plate, and the closing plate seals the corresponding air intake pipe under the action of the reset spring; so that the present invention can still work normally when the filling net cylinder is replaced, which is beneficial to improve the working efficiency of the present invention.

[0026] The present invention also provides a method for treating heavy metal contaminated soil by using natural mineral modified biochar. Based on the above-mentioned device for treating heavy metal contaminated soil by using natural mineral modified biochar, the method comprises the following steps:

[0027] S1. Fill the space between the isolation net cylinder and the adsorption cylinder with natural mineral modified biochar particles; place the heavy metal contaminated soil to be treated into the crushing box, and use the crushing motor to drive the crushing roller to rotate to crush the heavy metal contaminated soil; wherein the particle size of the natural mineral modified biochar particles is 3 to 5 mm; the particle size of the crushed heavy metal contaminated soil is 5 to 9 mm;

[0028] S2. The crushed heavy metal contaminated soil falls onto the surface of the conical mesh screen, and the separation motor drives the scraper plate on the rotating disk to rotate simultaneously. The scraper plate continuously scrapes the crushed heavy metal contaminated soil, so that the heavy metal contaminated soil passes through the conical mesh screen and falls to the area between the adsorption cylinder and the treatment box; the debris in the heavy metal contaminated soil is screened and removed by the conical mesh screen;

[0029] S3. Use a magnetron to receive the ultrasonic wave generated by the ultrasonic generator, and convert the ultrasonic wave into heat energy to diffuse into the contaminated soil, heating the heavy metal contaminated soil to 500-750°C; then turn on the exhaust fan, and the organic arsenic, organic cadmium, and organic mercury in the heavy metal contaminated soil are converted into gas after heating, and enter the natural mineral modified biochar particles through the suction pipe under the action of the exhaust fan, and the gaseous organic arsenic, organic cadmium, and organic mercury are adsorbed and removed when passing through the natural mineral modified biochar particles; wherein the frequency of the ultrasonic wave is 30-50kHz.

[0030] Compared with the prior art, the beneficial effects of the present invention are embodied in the following aspects:

[0031] First, the device structure of the present invention is reasonably designed. By heating the crushed heavy metal contaminated soil, the organic arsenic, organic cadmium and organic mercury in the heavy metal contaminated soil are converted into gaseous state. At this time, the gaseous organic arsenic, organic cadmium and organic mercury are extracted by the exhaust fan and adsorbed by the natural mineral modified biochar, thereby achieving the treatment of heavy metal contaminated soil.

[0032] Second, the present invention uses agricultural straw and bentonite as raw materials for preparing natural mineral modified biochar. Both biochar and natural minerals are porous materials. After the two are combined, they can play their respective advantages, make up for their respective deficiencies, and promote each other. The natural mineral modified biochar prepared by the present invention can adsorb and fix gaseous organic arsenic, organic cadmium, and organic mercury in the soil, and will not cause secondary pollution to the soil;

[0033] Third, the present invention fills the natural mineral modified biochar inside the filling net cylinder, and at the same time movably connects the filling net cylinder with the processing box, and uses an electric push rod to facilitate the removal of each filling net cylinder from the processing box, thereby facilitating the replacement of the natural mineral modified biochar particles inside the filling net cylinder; at the same time, the device of the present invention can still work normally when replacing the filling net cylinder, which is beneficial to improving the working efficiency of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a longitudinal sectional view of the device of the present invention;

[0035] Figure 2 is a front view of the device of the present invention;

[0036] Figure 3 is a schematic structural diagram of a pretreatment component of the present invention;

[0037] Figure 4 It is a schematic diagram of the connection between the conical mesh screen and the processing box of the present invention;

[0038] Figure 5 It is a schematic diagram of the connection between the scraper plate and the conical mesh screen of the present invention;

[0039] Figure 6 It is a schematic diagram of the connection between the suction pipe and the adsorption cylinder of the present invention;

[0040] Figure 7 The present invention Figure 1 A local enlarged schematic diagram of the middle A;

[0041] Figure 8 It is a schematic diagram of the connection between the sealing disk and the equipment box of the present invention;

[0042] Fig. 9 The present invention Figure 1 A partial enlarged schematic diagram of point B in the middle;

[0043] Among them, 1-processing box, 10-cleaning cover, 11-bracket, 2-pretreatment component, 20-crushing box, 200-cleaning brush, 21-crushing roller, 210-connecting gear, 22-crushing motor, 3-separation component, 30-conical mesh screen, 31-rotating disk, 32-scraper plate, 320-compression spring, 33-separation motor, 34-integrated sleeve, 4-adsorption component, 40-adsorption cylinder, 400-guide cone cylinder, 401-closing plate, 4010-plug rod, 4011-reset spring, 4 1-isolation net cylinder, 42-exhaust fan, 43-ultrasonic generator, 430-magnetron, 44-intake pipe, 440-branch pipe, 45-filling net cylinder, 450-push block, 46-conversion disk, 47-electric push rod, 5-equipment box, 50-sealing disk, 500-connecting block, 51-fan plate, 510-rotating shaft, 511-connecting gear, 52-pushing disk, 520-rack, 53-driving motor, 530-driving screw, 54-linkage ring, 540-limiting seat, 541-guide column. DETAILED DESCRIPTION

[0044] Example 1

[0045] like Figure 1 The device for treating heavy metal contaminated soil by using natural mineral modified biochar shown in the figure comprises a treatment box 1, a pretreatment component 2 arranged on the top of the treatment box 1, a separation component 3 and an adsorption component 4 arranged inside the treatment box 1; the adsorption component 4 is located below the separation component 3;

[0046] like Figure 1 , 2 As shown in Figure 3, the pre-processing component 2 includes a crushing box 20 that is arranged through the top of the processing box 1, a crushing roller 21 that is rotatably connected to the inside of the crushing box 20, and a crushing motor 22 that is arranged on the outer wall of the crushing box 20 and provides power for the crushing roller 21; two crushing rollers 21 are provided, and the two crushing rollers 21 are arranged horizontally and side by side inside the crushing box 20, and the ends of the two crushing rollers 21 both pass through the crushing box 20 and are provided with mutually meshing connecting gears 210; the crushing motor 22 is arranged on the outer wall of the crushing box 20 through a motor bracket, and the output end of the crushing motor 22 is connected to one of the crushing rollers 21;

[0047] like Figure 1 , 24, the separation assembly 3 includes a conical mesh screen 30 fixedly arranged inside the processing box 1, a rotating disk 31 rotatably connected to the upper end surface of the conical mesh screen 30, 15 scraper plates 32 equidistantly distributed around the rotating disk 31 and abutting against the surface of the conical mesh screen 30, and a separation motor 33 arranged at the top of the conical mesh screen 30 and providing power for the rotating disk 31; a cleaning cover 10 is arranged on the outer wall of the processing box 1 and at a position corresponding to the position of the conical mesh screen 30;

[0048] like Figure 1 , 6 As shown, the adsorption assembly 4 includes an adsorption cylinder 40 arranged at the bottom of the processing box 1, an isolation mesh cylinder 41 clamped in the inside of the adsorption cylinder 40, an exhaust fan 42 and an ultrasonic generator 43 arranged at the bottom of the processing box 1; a guide cone 400 connected to the conical mesh screen 30 is arranged at the top of the adsorption cylinder 40, and 6 suction pipes 44 are evenly distributed on the outer wall of the adsorption cylinder 40; natural mineral modified biochar particles are filled between the isolation mesh cylinder 41 and the adsorption cylinder 40; an exhaust joint connected to the inside of the isolation mesh cylinder 41 is arranged at the bottom of the processing box 1, and the input end of the exhaust fan 42 is connected to the exhaust joint; 15 magnetrons 430 respectively connected to the ultrasonic generator 43 are evenly distributed on the inner wall of the processing box 1 and corresponding to the position of the adsorption cylinder 40; wherein, the natural mineral modified biochar particles adopt the existing technology.

[0049] Example 2

[0050] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. Based on the device for treating heavy metal contaminated soil by using natural mineral modified biochar in Example 1, the method comprises the following steps:

[0051] S1. Fill the space between the isolation net tube 41 and the adsorption tube 40 with natural mineral modified biochar particles; place the heavy metal contaminated soil to be treated into the crushing box 20, and use the crushing motor 22 to drive the crushing roller 21 to rotate, so as to crush the heavy metal contaminated soil; wherein the particle size of the natural mineral modified biochar particles is 3 to 4 mm; the particle size of the crushed heavy metal contaminated soil is 5 to 7 mm;

[0052] S2, the crushed heavy metal contaminated soil falls onto the surface of the conical mesh screen 30, and the separation motor 33 drives the scraper plate 32 on the rotating disk 31 to rotate simultaneously, and the scraper plate 32 continuously scrapes the crushed heavy metal contaminated soil, so that the heavy metal contaminated soil passes through the conical mesh screen 30 and falls to the area between the adsorption cylinder 40 and the treatment box 1; the debris in the heavy metal contaminated soil is screened and removed by the conical mesh screen 30;

[0053] S3. Utilize the magnetron 430 to receive the ultrasonic wave generated by the ultrasonic generator 43, and convert the ultrasonic wave into heat energy to diffuse into the contaminated soil, and heat the heavy metal contaminated soil to 500°C; then turn on the exhaust fan 42, and the organic arsenic, organic cadmium, and organic mercury in the heavy metal contaminated soil are converted into gas after heating, and enter the natural mineral modified biochar particles through the suction pipe 44 under the action of the exhaust fan 42, and the gaseous organic arsenic, organic cadmium, and organic mercury are adsorbed and removed when passing through the natural mineral modified biochar particles; wherein the frequency of the ultrasonic wave is 30kHz.

[0054] Example 3

[0055] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. The device for treating heavy metal contaminated soil by using natural mineral modified biochar based on Example 1 is different from Example 2 in that:

[0056] In step S1, the particle size of the natural mineral modified biochar particles is 4 to 5 mm; the particle size of the crushed heavy metal contaminated soil is 7 to 9 mm;

[0057] In step S3, the heavy metal contaminated soil is heated to 600° C.; the frequency of the ultrasonic wave is 40 kHz.

[0058] Example 4

[0059] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. The device for treating heavy metal contaminated soil by using natural mineral modified biochar based on Example 1 is different from Example 3 in that:

[0060] In step S3, the heavy metal contaminated soil is heated to 750° C.; the frequency of the ultrasonic wave is 50 kHz.

[0061] Example 5

[0062] The present embodiment is different from the first embodiment in that 20 scraper plates 32 are provided, 10 suction pipes 44 are provided, and 20 magnetrons 430 are provided.

[0063] Example 6

[0064] The difference between this embodiment and embodiment 1 is that:

[0065] The method for preparing natural mineral modified biochar particles comprises the following steps:

[0066] S1. In an anaerobic state, agricultural straw is pyrolyzed and carbonized at 400°C for 1 h to obtain biochar;

[0067] S2: crushing the bentonite and sieving it through a 120-mesh sieve for later use; mixing sodium sulfide and the sieved bentonite at a mass ratio of 1:100, and then placing it at a temperature of 100° C. for 60 minutes for sulfurization modification to obtain sulfurized modified bentonite;

[0068] S3, the sulfide modified bentonite obtained in step S2 and the biochar obtained in step S1 are stirred and evenly mixed in a mass ratio of 1:3, and then placed in a hydrothermal carbonization furnace, and hydrothermally carbonized at 300° C. for 1 hour; after the treatment is completed, naturally cool to room temperature to obtain natural mineral modified biochar particles with a particle size of 3 to 5 mm;

[0069] Biochar and natural minerals are both porous materials. After the two are combined, they can play their respective advantages, make up for their respective deficiencies, and promote each other. Biochar is stronger than natural minerals in degrading COD and phosphorus, but natural minerals are stronger than biochar in adsorbing heavy metals. The natural mineral modified biochar prepared by the present invention can absorb gaseous organic arsenic, organic cadmium, and organic mercury in the soil without causing secondary pollution to the soil.

[0070] Example 7

[0071] The difference between this embodiment and embodiment 6 is that:

[0072] In step S1, in an anaerobic state, agricultural straw is pyrolyzed and carbonized at 600° C. for 2 h to obtain biochar;

[0073] In step S2, sodium sulfide and the sieved bentonite are mixed in a mass ratio of 1:10 and placed at a temperature of 150° C. for 170 minutes for sulfurization modification to obtain sulfurized modified bentonite;

[0074] In step S3, the sulfide-modified bentonite obtained in step S2 and the biochar obtained in step S1 are stirred and mixed in a mass ratio of 1:3, placed in a hydrothermal carbonization furnace, and hydrothermally carbonized for 3 hours at 650°C; after the treatment is completed, the mixture is naturally cooled to room temperature to obtain natural mineral-modified biochar particles with a particle size of 5 to 7 mm.

[0075] Example 8

[0076] The difference between this embodiment and embodiment 6 is that:

[0077] like Figure 3 As shown, a cleaning brush 200 is provided inside the crushing box 20 to abut against the crushing roller 21;

[0078] The cleaning brush 200 can be used to clean the mud stuck on the crushing roller 21 to ensure the use effect of the crushing roller 21.

[0079] Example 9

[0080] The difference between this embodiment and embodiment 8 is that:

[0081] like Figure 5 As shown, an integrated sleeve 34 is provided inside the processing box 1 and at the upper end where the conical mesh screen 30 and the processing box 1 are connected; one end of each scraper plate 32 is respectively slidably engaged with the integrated sleeve 34, and the other end is respectively slidably engaged with the rotating disk 31, and both ends of the upper end surface of the scraper plate 32 are provided with compression springs 320 that abut against the integrated sleeve 34 and the rotating disk 31 respectively;

[0082] By slidingly engaging the two ends of the scraper plate 32 with the integrated sleeve 34 and the rotating disk 31 respectively, the scraper plate 32 is always in close contact with the upper end surface of the conical mesh screen 30 under the action of the compression spring 320, which can prevent soil particles from accumulating on the surface of the conical mesh screen 30 and causing blockage.

[0083] Example 10

[0084] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. The device for treating heavy metal contaminated soil by using natural mineral modified biochar based on Example 9 is different from Example 2 in that:

[0085] In step S2 , when the scraper plate 32 rotates with the rotating disk 31 , the scraper plate 32 is always in close contact with the upper end surface of the conical mesh screen 30 under the action of the compression spring 320 .

[0086] Embodiment 11

[0087] The difference between this embodiment and embodiment 9 is that:

[0088] like Figure 1 , 8 As shown in Figures 9 and 10, an equipment box 5 is provided at the upper end of the adsorption cylinder 40, and the guide cone 400 is connected to the equipment box 5; a sealing disk 50 is sleeved on the outside of the equipment box 5, and 8 sector plates 51 are rotatably clamped on the sealing disk 50; each sector plate 51 is rotatably clamped with the sealing disk 50 through a rotating shaft 510, each rotating shaft 510 passes through the equipment box 5, and each rotating shaft 510 is sleeved with a connecting gear 511; a pushing disk 52 is provided above the equipment box 5, and a rack 520 that passes through the equipment box 5 and is meshed with the connecting gear 511 at the corresponding position is provided on the lower bottom surface of the pushing disk 52 and at the corresponding position of each connecting gear 511; a driving motor 53 is provided at the top of the equipment box 5, and a driving screw 530 that passes through the equipment box 5 and is threadedly connected to the pushing disk 50 is provided at the output end of the driving motor 53;

[0089] The sealing disk 50 is provided to help reduce heat loss during heating of heavy metal contaminated soil, which helps reduce energy consumption of the device.

[0090] Example 12

[0091] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. The device for treating heavy metal contaminated soil by using natural mineral modified biochar based on Example 11 is different from Example 10 in that:

[0092] In step S3, the driving motor 53 is used to drive the driving screw 530 to rotate, so that the pushing plate 52 drives each rack 520 to move downward along the equipment box 5 under the action of the driving screw 530. During the movement of the rack 520, the connecting gear 511 and the fan plate 51 are driven to rotate at the same time to seal the sealing plate 50.

[0093] Example 13

[0094] The difference between this embodiment and embodiment 11 is that twelve sector plates 51 are rotatably clamped on the sealing disk 50 .

[0095] Embodiment 14

[0096] The difference between this embodiment and embodiment 11 is that:

[0097] like Figure 1 , 9 As shown, a linkage ring 54 is sleeved inside the equipment box 5, and connection blocks 500 penetrating the equipment box 5 and connected to the linkage ring 54 are arranged at the circumference of the sealing disk 50 and at positions corresponding to the rotating shaft 510; the connection blocks 500 are slidably engaged with the equipment box 5, and the rotating shaft 510 penetrates the connection blocks 500 at corresponding positions; limited seats 540 are arranged on the lower bottom surface of the linkage ring 54 and at positions corresponding to the positions of each rack 520; and guide columns 541 movably plugged with the rack 520 are arranged on the lower bottom surface of the limited seats 540;

[0098] When the sealing disk 50 is in a sealed state, each rack 520 is respectively abutted against the limit seat 540 at the corresponding position. At this time, the driving motor 53 is used to continue to drive the pushing disk 52 to move downward. At this time, each rack 520 squeezes the limit seat 540 at the corresponding position, and the linkage ring 54 drives the sealing disk 50 to move downward along the adsorption cylinder 40 through the connecting block 500. The driving motor 53 is used to continue to drive the pushing disk 52 to move downward, and the heated heavy metal contaminated soil is compacted, which is beneficial to improve the adsorption and fixation efficiency of gaseous organic arsenic, organic cadmium and organic mercury in the soil.

[0099] Embodiment 15

[0100] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. The device for treating heavy metal contaminated soil by using natural mineral modified biochar based on Example 14 is different from Example 12 in that:

[0101] In step S3, when the sealing disk 50 is in a sealed state, each rack 520 is respectively abutted against the limit seat 540 at the corresponding position. At this time, the driving motor 53 is used to continue to drive the push disk 52 to move downward. At this time, each rack 520 squeezes the limit seat 540 at the corresponding position, and the linkage ring 54 drives the sealing disk 50 to move downward along the adsorption cylinder 40 through the connecting block 500. The driving motor 53 is used to continue to drive the push disk 52 to move downward, so as to compact the heated heavy metal contaminated soil.

[0102] Example 16

[0103] The difference between this embodiment and embodiment 14 is that:

[0104] like Figure 1 , 6 As shown in Figures 7 and 8, a bracket 11 is provided at the lower end of the treatment box 1; six filling net cylinders 45 are evenly distributed between the isolation net cylinder 41 and the adsorption cylinder 40; the lower end of each filling net cylinder 45 penetrates the treatment box 1 and is movably connected to the treatment box 1 by bolts; each filling net cylinder 45 is connected to each suction pipe 44 one by one; a conversion disk 46 is provided at the bottom of the bracket 11, and an electric push rod 47 that can be clamped with the bottom end of any filling net cylinder 45 is provided on the upper end surface of the conversion disk 46; A closing plate 401 is slidably engaged with the inner wall at the position corresponding to each suction pipe 44; a plug-in rod 4010 is provided on the closing plate 401 to be slidably engaged with the adsorption cylinder 40, and a return spring 4011 is provided at the top of the plug-in rod 4010 to abut against the adsorption cylinder 40; a shifting block 450 capable of being movably engaged with the closing plate 401 is provided on the outer wall of the filling net cylinder 45; branch pipes 440 are provided at the upper and lower ends of each suction pipe 44, and suction micropores are penetrated on the side walls of each branch pipe 440;

[0105] By loading the natural mineral modified biochar particles into each filling net tube 45, and movably connecting each filling net tube 45 with the processing box 1, the electric push rod 47 is used to facilitate the removal of each filling net tube 45 from the processing box 1, thereby facilitating the replacement of the natural mineral modified biochar particles in the filling net tube 45; when it is necessary to replace the natural mineral modified biochar particles in a certain filling net tube 45 and take out the filling net tube 45, the corresponding shifting block 450 is separated from the closing plate 401, and the closing plate 401 seals the corresponding air intake pipe 44 under the action of the reset spring 4011; so that the present invention can still work normally when the filling net tube 45 is replaced, which is beneficial to improving the working efficiency of the present invention.

[0106] Embodiment 17

[0107] This embodiment describes a method for treating heavy metal contaminated soil by using natural mineral modified biochar. The device for treating heavy metal contaminated soil by using natural mineral modified biochar based on Example 16 is different from Example 15 in that it also includes step S4;

[0108] S4. When it is necessary to replace the natural mineral modified biochar inside a filling net tube 45, rotate the conversion disk 46, dock the electric push rod 47 with the corresponding filling net tube 45, and use the electric push rod 47 to take out the filling net tube 45 from the inside of the processing box 1; when the filling net tube 45 is taken out, the corresponding shift block 450 is separated from the closing plate 401, and the closing plate 401 seals the corresponding intake pipe 44 under the action of the reset spring 4011.

[0109] It should be noted that the crushing motor 22, separation motor 33, exhaust fan 42, ultrasonic generator 43, magnetron 430, electric push rod 47 and drive motor 53 used in the present invention all adopt existing technologies, and are not specifically limited here. The corresponding products can be selected according to actual needs.

[0110] Test example

[0111] The heavy metal contaminated soil of a certain electroplating plant was treated by using the devices of Examples 1, 4, 8, 9, 11, 14, and 16 of the present invention, respectively. After the treatment, the concentrations of organic arsenic, organic cadmium, and organic mercury discharged from the devices of each embodiment were detected, and the results are shown in Table 1:

[0112] Table 1 Concentrations of organic arsenic, organic cadmium and organic mercury in the discharge of the device after heavy metal contaminated soil treatment in each embodiment

[0113] Example Organic arsenic concentration mg / kg Organic cadmium concentration mg / kg Organic mercury concentration mg / kg 1 25 0.45 0.15 4 25 0.42 0.15 8 23 0.40 0.13 9 22 0.38 0.14 11 22 0.39 0.12 14 19 0.33 0.11 16 17 0.31 0.11

[0114] It can be seen from the data in Table 1 that the heavy metal contaminated soil of a certain electroplating plant was treated using the devices of Examples 1, 4, 8, 9, 11, 14, and 16 of the present invention, and the concentrations of organic arsenic, organic cadmium, and organic mercury discharged from the devices all met the requirements of the "Soil Environmental Quality Standard" (GB 15618-2018); among them, the heavy metal contaminated soil was treated using the device of Example 16, and the concentrations of organic arsenic, organic cadmium, and organic mercury discharged from the device were the lowest, and all the data were better than those of the devices of other embodiments, and the device of Example 16 was the optimal equipment.

Claims

1. A device for treating heavy metal contaminated soil using natural mineral modified biochar, characterized in that: It comprises a processing box (1), a pre-processing component (2), a separation component (3) and an adsorption component (4); The pre-processing assembly (2) comprises a crushing box (20) arranged at the top of the processing box (1), a crushing roller (21) clamped inside the crushing box (20), and a crushing motor (22) providing power to the crushing roller (21); The separation assembly (3) comprises a conical mesh screen (30) arranged inside the processing box (1), a rotating disk (31) rotatably clamped on the upper end surface of the conical mesh screen (30), a scraper plate (32) arranged in the circumference of the rotating disk (31), and a separation motor (33) providing power to the rotating disk (31); The adsorption assembly (4) comprises an adsorption cylinder (40) arranged at the bottom of the processing box (1), an isolation net cylinder (41) clamped inside the adsorption cylinder (40), an exhaust fan (42) and an ultrasonic generator (43) arranged at the bottom end of the processing box (1); a guide cone cylinder (400) is arranged at the top end of the adsorption cylinder (40), and an air intake pipe (44) is arranged on the outer wall of the adsorption cylinder (40); natural mineral modified biochar particles are filled between the isolation net cylinder (41) and the adsorption cylinder (40); an exhaust joint connected to the exhaust fan (42) is arranged at the bottom end of the processing box (1); and a magnetron (430) connected to the ultrasonic generator (43) is arranged on the inner wall of the processing box (1).

2. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 1, characterized in that: The method for preparing the natural mineral modified biochar particles comprises the following steps: S1. In an anaerobic state, the agricultural straw is pyrolyzed and carbonized at a temperature of 400 to 600°C for 1 to 2 hours to obtain biochar; S2, crushing the bentonite and sieving it through a 120-mesh sieve for standby use; mixing sodium sulfide and the sieved bentonite in a mass ratio of 1 to 10:100, and placing it at a temperature of 100 to 150° C. for 60 to 170 minutes for vulcanization modification to obtain vulcanized modified bentonite; S3. The sulfide-modified bentonite obtained in step S2 and the biochar obtained in step S1 are stirred and evenly mixed in a mass ratio of 1:3, and then placed in a hydrothermal carbonization furnace, and subjected to hydrothermal carbonization treatment at a temperature of 300-650° C. for 1-3 hours; after the treatment is completed, the mixture is naturally cooled to room temperature to obtain natural mineral-modified biochar particles with a particle size of 3-7 mm.

3. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 1, characterized in that: An integrated sleeve (34) is arranged inside the processing box (1) and at the upper end of the connection between the conical mesh screen (30) and the processing box (1); one end of each of the scraper plates (32) is respectively slidably engaged with the integrated sleeve (34), and the other end is respectively slidably engaged with the rotating disk (31); and both ends of the upper end surface of the scraper plate (32) are provided with compression springs (320) respectively abutting against the integrated sleeve (34) and the rotating disk (31).

4. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 1, characterized in that: An equipment box (5) is provided at the upper end of the adsorption cylinder (40), and the guide cone (400) is connected to the equipment box (5); a sealing disk (50) is sleeved on the outside of the equipment box (5), and a plurality of sector plates (51) are rotatably engaged with the sealing disk (50); each sector plate (51) is rotatably engaged with the sealing disk (50) via a rotating shaft (510), each rotating shaft (510) passes through the equipment box (5), and each rotating shaft (510) is sleeved with a connecting gear (510). 11); a driving plate (52) is arranged above the equipment box (5); a rack (520) is arranged on the bottom surface of the driving plate (52) and at positions corresponding to the positions of the connecting gears (511), penetrating the equipment box (5) and meshingly connected with the connecting gears (511) at corresponding positions; a driving motor (53) is arranged at the top of the equipment box (5); a driving screw (530) is arranged at the output end of the driving motor (53), penetrating the equipment box (5) and threadedly connected to the driving plate (50).

5. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 4, characterized in that: A linkage ring (54) is sleeved inside the equipment box (5); connection blocks (500) penetrating the equipment box (5) and connected to the linkage ring (54) are arranged circumferentially on the sealing disk (50) and at positions corresponding to the rotating shaft (510); the connection blocks (500) are slidably engaged with the equipment box (5), and the rotating shaft (510) penetrates the connection blocks (500) at corresponding positions; and limit seats (540) are arranged on the lower surface of the linkage ring (54) and at positions corresponding to the positions of the racks (520).

6. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 5, characterized in that: The lower bottom surface of the limiting seat (540) is provided with a guide column (541) movably plugged with the rack (520).

7. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 1, characterized in that: A bracket (11) is provided at the lower end of the processing box (1); a plurality of filling net cylinders (45) are equidistantly distributed between the isolation net cylinder (41) and the adsorption cylinder (40); the lower end of each of the filling net cylinders (45) penetrates the processing box (1) and is movably connected to the processing box (1) by bolts; each of the filling net cylinders (45) is connected to each of the suction pipes (44) in a one-to-one correspondence; a conversion disk (46) is provided at the bottom of the bracket (11), and an electric push rod (47) is provided on the upper end surface of the conversion disk (46) which can be clamped with the bottom end of any filling net cylinder (45).

8. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 7, characterized in that: A closing plate (401) is slidably engaged on the inner wall of the adsorption cylinder (40) and at positions corresponding to the positions of each suction pipe (44); a plug-in rod (4010) is provided on the closing plate (401) and is slidably engaged with the adsorption cylinder (40); a return spring (4011) is provided at the top of the plug-in rod (4010) and is in contact with the adsorption cylinder (40); and a shifting block (450) that can be movably engaged with the closing plate (401) is provided on the outer wall of the filling net cylinder (45).

9. A method for treating heavy metal contaminated soil by using natural mineral modified biochar, based on the device for treating heavy metal contaminated soil by using natural mineral modified biochar according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1, filling the space between the isolation net cylinder (41) and the adsorption cylinder (40) with natural mineral modified biochar particles; placing the heavy metal contaminated soil to be treated into the crushing box (20), using the crushing motor (22) to drive the crushing roller (21) to rotate, and crushing the heavy metal contaminated soil; wherein the particle size of the natural mineral modified biochar particles is 3 to 5 mm; and the particle size of the crushed heavy metal contaminated soil is 5 to 9 mm; S2, the crushed heavy metal contaminated soil falls onto the surface of the conical mesh screen (30), and the separation motor (33) drives the scraper plate (32) on the rotating disk (31) to rotate simultaneously, and the scraper plate (32) continuously scrapes the crushed heavy metal contaminated soil, so that the heavy metal contaminated soil passes through the conical mesh screen (30) and falls to the area between the adsorption cylinder (40) and the treatment box (1); the impurities in the heavy metal contaminated soil are sieved and removed by the conical mesh screen (30); S3, using a magnetron (430) to receive the ultrasonic wave generated by the ultrasonic generator (43), and converting the ultrasonic wave into heat energy to diffuse into the contaminated soil, heating the heavy metal contaminated soil to 500-750° C.; then turning on the exhaust fan (42), the organic arsenic, organic cadmium, and organic mercury in the heavy metal contaminated soil are converted into a gas state after heating, and enter the natural mineral modified biochar particles through the suction pipe (44) under the action of the exhaust fan (42), and the gaseous organic arsenic, organic cadmium, and organic mercury are adsorbed and removed when passing through the natural mineral modified biochar particles; wherein the frequency of the ultrasonic wave is 30-50 kHz.

10. The device for treating heavy metal contaminated soil by using natural mineral modified biochar according to claim 1, characterized in that: A guide column (541) is provided on the lower surface of the limiting seat (540), and the guide column (541) is movably plugged into the rack (520).

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