CN112605115B

CN112605115B - Heavy metal contaminated soil remediation device and method

Info

Publication number: CN112605115B
Application number: CN202011542616.3A
Authority: CN
Inventors: 黄文涛; 丁海涛; 陆宏宇; 邓呈逊; 俞志敏
Original assignee: Hefei University
Current assignee: Hefei University
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-08-03
Anticipated expiration: 2040-12-24
Also published as: CN112605115A

Abstract

The invention discloses a heavy metal contaminated soil remediation device, which comprises a coarse filtration device, a fine filtration device and an electric remediation device, wherein the coarse filtration device, the fine filtration device and the electric remediation device are sequentially connected; according to the invention, large stones in soil can be removed through the coarse filtering device, small sand grains can be removed through the fine filtering device, and finally the soil is subjected to electric restoration treatment, so that the soil can be comprehensively and efficiently restored.

Description

Heavy metal contaminated soil remediation device and method

Technical Field

The invention relates to the field of soil remediation, in particular to a device and a method for remediating heavy metal contaminated soil.

Background

In recent years, various activities of human beings have increasingly influenced the soil environment, and the heavy metal pollution of the soil is increasingly serious. The heavy metal pollution sources of soil are wide, mainly come from production and living activities of human beings, including mining, smelting, metal processing, chemical industry, waste battery treatment, electronic, tanning, dye and other industrial emission three wastes and automobile exhaust emission, pesticide and chemical fertilizer application and other great damages to the soil, so that the soil is polluted, food can be planted in the soil, the pollution caused by the human beings to the soil can finally return to the inside of the human body, various diseases occur to the human body, and the soil remediation is very important.

Disclosure of Invention

1. Technical problem to be solved

Aiming at the problem that the soil is polluted and needs to be repaired in the prior art, the invention aims to provide a device and a method for repairing the soil polluted by heavy metal, which can realize high-efficiency repair and purification of the heavy metal in the soil.

2. Technical scheme

In order to solve the above problems, the present invention adopts the following technical solutions.

The heavy metal contaminated soil remediation device comprises a coarse filtration device, a fine filtration device and an electric remediation device, wherein the coarse filtration device, the fine filtration device and the electric remediation device are sequentially connected;

the coarse filtering device comprises a round drum type stone remover and a coarse filtering tank, the round drum type stone remover is horizontally placed, the lower part of the round drum type stone remover is immersed in the coarse filtering tank, analytic liquid is mixed in the coarse filtering tank, a plurality of small holes are formed in the inner wall of the round drum type stone remover, and the bottom end of the coarse filtering tank is connected with the fine filtering device through a first pipeline;

the inner walls of the coarse filter tank at the two ends of the round drum type stone remover are provided with bearing tables with the same curvature radius as that of the round drum type stone remover, the bearing tables bear the two ends of the round drum type stone remover, the outer wall of the middle position of the round drum type stone remover is fixedly connected with a circle of driven gears, and the coarse filter tank is provided with a first motor which is connected with the driven gears through a driving gear;

the fine filtering device comprises a fine filtering tank, a gravel bin and a vibrating screen, wherein one side of the fine filtering tank is connected with the gravel bin, one side of the vibrating screen, which is close to the gravel bin, is rotatably connected with the top end of the fine filtering tank, one end of the fine filtering tank, which is far away from the gravel bin, is connected with a second motor, the second motor is connected with a triangular gear, and the vibrating screen is positioned above the triangular gear;

the first pipeline is positioned above the vibrating screen close to one side of the second motor, the fine filter tank is also provided with a complexing agent box, the bottom end of the fine filter tank is connected with the coarse filter tank through a circulating pipe, and the bottom end of the fine filter tank is connected with the electric repair device through a second pipeline;

the vibrations screen cloth top middle part be connected with the third motor, the third motor be connected with the pivot, the pivot run through inside the vibrations screen cloth extends to thin filtering ponds, the side of pivot is connected with a plurality of puddlers.

Preferably, the electric repairing device comprises an electric repairing pool, a first anode electrode is arranged at one end inside the electric repairing pool, a cathode electrode is arranged at the opposite end, a plurality of second anode electrodes are further arranged inside the electric repairing pool, permeation reaction walls are arranged on the sides, close to the first anode electrode, of the second anode electrodes and the cathode electrodes, the cathode electrodes are connected with a cathode of a power supply, and the first anode electrode and the second anode electrode are connected with an anode of the power supply through a switch;

and third pipelines are arranged at the bottom ends between the first anode electrode and the second anode electrode, between the second anode electrodes and between the second anode electrode and the cathode electrode, and are connected with a mud-water filter press.

Preferably, the repairing method comprises the following steps:

firstly, placing soil to be repaired in a coarse filtration device for coarse filtration to remove large stones;

secondly, the soil after coarse filtration enters a fine filtration device for fine filtration to remove small gravel;

and thirdly, the finely filtered soil enters an electric repairing device for electric repairing, and the purified soil is discharged.

3. Advantageous effects

Compared with the prior art, the invention has the advantages that: according to the invention, large stones in soil can be removed through the coarse filtering device, small sand grains can be removed through the fine filtering device, and finally the soil is subjected to electric restoration treatment, so that the soil can be comprehensively and efficiently restored.

Drawings

FIG. 1 is a schematic flow diagram of the present invention;

FIG. 2 is a schematic view of the structure of the coarse filter device of the present invention;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2 in accordance with the present invention;

FIG. 4 is a schematic view of the construction of a fine filtration apparatus of the present invention;

FIG. 5 is a schematic view of a triangular gear of the present invention;

fig. 6 is a schematic structural view of the electric prosthetic device of the present invention.

The reference numbers in the figures illustrate:

1. a coarse filtration device; 2. a fine filtration device; 3. an electrically powered prosthetic device;

101. a drum type stoner; 102. a coarse filtration tank; 103. a small hole; 104. a first conduit; 105. a bearing table; 106. a driven gear;

201. a fine filtration tank; 202. a gravel bin; 203. vibrating the screen; 204. a second motor; 205. a triangular gear; 206. a complexing agent box; 207. a circulation pipe; 208. a third motor; 209. a rotating shaft; 210. a stirring rod; 211. a second conduit;

301. an electric restoration pool; 302. a first anode electrode; 303. a cathode electrode; 304. a second anode electrode; 305. a permeable reactive barrier; 306. a power source; 307. a switch; 308. a third conduit.

Detailed Description

The drawings in the embodiments of the invention will be combined; the technical scheme in the embodiment of the invention is clearly and completely described; obviously; the described embodiments are only some of the embodiments of the invention; rather than all embodiments. Based on the embodiments of the invention; all other embodiments obtained by a person skilled in the art without making any inventive step; all fall within the scope of protection of the present invention.

Referring to fig. 1-6, a heavy metal contaminated soil remediation device comprises a coarse filtration device 1, a fine filtration device 2 and an electric remediation device 3, wherein the coarse filtration device 1, the fine filtration device 2 and the electric remediation device 3 are connected in sequence.

Coarse filtration device 1 includes cylinder formula stoner 101 and thick filtering ponds 102, and cylinder formula stoner 101 level is placed and lower part submergence in thick filtering ponds 102, mixes in thick filtering ponds 102 and has analyzed liquid, and a plurality of apertures 103 have been seted up to cylinder formula stoner 101 inner wall, and thin filter equipment 2 is connected through first pipeline 104 to the bottom of thick filtering ponds 102.

The inner walls of the rough filtering tank 102, which are positioned at the two ends of the circular drum type stone remover 101, are provided with bearing tables 105 which have the same curvature radius as that of the circular drum type stone remover 101, the bearing tables 105 bear the two ends of the circular drum type stone remover 101, the outer wall of the middle position of the circular drum type stone remover 101 is fixedly connected with a circle of driven gear 106, and the rough filtering tank 102 is provided with a first motor which is connected with the driven gear 106 through a driving gear.

The fine filtering device 2 comprises a fine filtering tank 201, a gravel bin 202 and a vibrating screen 203, wherein one side of the fine filtering tank 201 is connected with the gravel bin 202, one side of the vibrating screen 203, which is close to the gravel bin 202, is rotatably connected with the top end of the fine filtering tank 201, one end of the fine filtering tank 201, which is far away from the gravel bin 202, is connected with a second motor 204, the second motor 204 is connected with a triangular gear 205, and the vibrating screen 203 is positioned above the triangular gear 205;

the first pipeline 104 is positioned above one side of the vibrating screen 203 close to the second motor 204, the fine filter tank 201 is also provided with a complexing agent box 206, the bottom end of the fine filter tank 201 is connected with the coarse filter tank 102 through a circulating pipe 207, and the bottom end of the fine filter tank 201 is connected with the electric restoration device 3 through a second pipeline 211.

The middle part of the top of the vibration screen 203 is connected with a third motor 208, the third motor 208 is connected with a rotating shaft 209, the rotating shaft 209 penetrates through the vibration screen 203 and extends to the inside of the fine filter tank 201, and the side surface of the rotating shaft 209 is connected with a plurality of stirring rods 210.

The electric repairing device 3 comprises an electric repairing pool 301, wherein a first anode electrode 302 is arranged at one end inside the electric repairing pool 301, a cathode electrode 303 is arranged at the opposite end, a plurality of second anode electrodes 304 are further arranged inside the electric repairing pool 301, a permeable reaction wall 305 is arranged on one sides of the second anode electrodes 304 and the cathode electrodes 303 close to the first anode electrode 302, the cathode electrodes 303 are connected with the cathode of a power supply 306, and the first anode electrode 302 and the second anode electrode 304 are connected with the anode of the power supply 306 through a switch 307;

third pipelines 308 are arranged at the bottom ends between the first anode electrode 302 and the second anode electrode 304, between the second anode electrodes 304 and each other and between the second anode electrode 304 and the cathode electrode 303, and the third pipelines 308 are connected with a mud-water filter press.

A heavy metal contaminated soil restoration device comprises a restoration method:

firstly, placing soil to be repaired in a coarse filtration device 1 for coarse filtration to remove large stones;

secondly, the soil after coarse filtration enters a fine filtration device 2 for fine filtration to remove small gravel;

and thirdly, the finely filtered soil enters an electric restoration device 3 for electric restoration, and the purified soil is discharged.

The working principle is as follows:

firstly, placing soil to be repaired in a coarse filtration device 1 for coarse filtration to remove large stones; the half of the drum type stone remover is immersed in the resolving liquid, the contaminated soil is conveyed into the drum type stone remover, the drum is rotated, and the contaminated soil is dissolved under the action of the resolving liquid to form slurry which flows out of gaps of the drum; the large stone blocks in the soil are rotationally pushed to one side in the rotation process of the roller to be removed.

The function is as follows: on one hand, separating large stones from the soil, and on the other hand, preliminarily resolving heavy metals in the soil, so that the heavy metals adsorbed or fixed on the surface of soil particles are released into resolving liquid due to the dissolution of the soil particles;

secondly, the soil after coarse filtration enters a fine filtration device 2 for fine filtration to remove small gravel; and conveying the slurry obtained in the first step to a silt vibration screen through a first pipeline so as to remove small sand grains. And (3) the slurry with sand grains removed enters a fine filter tank, a complexing agent is added, the third motor is kept to drive the rotating shaft to be continuously stirred, so that the pollution components in the soil are fully and uniformly mixed with the complexing agent, the heavy metal components and the complexing agent are guaranteed to be fully reacted to generate a complex, and the heavy metal migration capacity is improved. Then the heavy metals enter corresponding soil remediation chambers through second pipelines respectively to remove the heavy metals in the soil;

the third motor is located vibrations screen cloth top can drive pivot and puddler up-and-down motion at the in-process that vibrations screen cloth shakes, thereby can be better faster realize the stirring, vibrations screen cloth can continuous up-and-down motion under the effect that the second motor drove triangular gear, thereby realize lasting vibrations, the in-process of vibrations, soil can enter into thin filtering ponds through vibrations screen cloth, and continuous downstream under the effect of vibrations is then followed to fritter gravel etc. finally falls into in the gravel storehouse.

Thirdly, the finely filtered soil enters an electric restoration device 3 for electric restoration, and the purified soil is discharged; as shown in fig. 6, when 2 second positive electrodes are arranged, the electric remediation pool is divided into a No. 1 soil remediation room, a No. 2 soil remediation room and a No. 3 soil remediation room from left to right, and the switches are a No. 1 switch, a No. 2 switch and a No. 3 switch from left to right;

the specific design content of the electric repairing device is as follows: an anode approach method is adopted, the permeation reaction wall device is used for adsorbing and fixing heavy metals, and an anion exchange membrane (not shown in the figure) is designed between the permeation reaction wall and the electrode chamber; a water inlet is further arranged on one side of the lower side port of the cathode chamber, the pH value of the cathode electric repairing chamber is adjusted through a buffer solution, and an overflow port is further arranged on the upper side port of the cathode chamber; the overflow port enters an anode electric repair chamber through a pipeline (not shown in the figure, and is not described again because of the prior art);

the direct current electric field is applied to the polluted soil in two sections, and under the action of the electric field force, the pollutants are directionally migrated in the soil interstitial fluid, so that the pollutants are enriched to one side of the soil or the electric repair fluid, the purpose of soil repair is achieved, and the specific operation is as follows:

the pretreated slurry enters all the soil remediation chambers through a pipeline, the heavy metal can migrate from the anode to the cathode under the action of an electric field force by turning on the No. 1 switch, and can be adsorbed and fixed when migrating to the permeable reactive wall device so as to transfer the heavy metal in the soil, because the electrifying process is also the process of electrically remedying water, at this time, a large amount of H + generated by the anode can enter the soil chamber, the heavy metal in the soil can be desorbed again, the soil heavy metal migration is promoted, but a large amount of OH is generated in the cathode electrically remediating chamber, if the OH-generated by the cathode electrically remediating chamber enters the soil chamber, the heavy metal in the soil can be precipitated, the pH of the soil can be regulated by an additional buffer solution, but because the buffer solution and the electroosmotic flow are added, the cathode electrically remediating liquid can overflow, the overflowing electrically remediating liquid enters the anode electrically remediating liquid through the pipeline, and the anode electrically remediating liquid can be regulated, and the pH value of the anode electrokinetic repair liquid is prevented from being too low, so that the electrode is prevented from being corroded.

The No. 1 soil remediation chamber can firstly complete remediation, and H + generated by the No. 1 electric remediation liquid enters the No. 1 electric remediation chamber, so that desorption of heavy metals in the soil is promoted, and the remediation process is accelerated; after the No. 1 soil is repaired, the anode is switched to a No. 2 soil repairing room; pumping the repaired No. 1 soil into a mud-water filter press through slurry for dehydration, introducing the dehydrated water into a pretreatment analysis liquid for reuse, and simultaneously re-injecting the slurry into the No. 1 soil chamber; and by analogy, the soil chamber 2 is repaired, the slurry is dehydrated and reinjected, the soil chamber 3 is repaired, the slurry is dehydrated and reinjected, and the operation is switched to the operation No. 1. And refilling the polluted site with the dehydrated mud cakes and the sand produced by the pretreatment.

The electrode chamber is arranged: the electrode is the titanium net, and the cylindric graphite electrode of granule is filled around to form the third electrode, but the electrochemical reaction takes place at the third pole surface to portable ion for reaction efficiency compares with traditional two-dimensional electrode, and it can effectively increase the specific surface area of electrode, accelerates the migration rate of material, promotes material mass transfer effect, strengthens current efficiency simultaneously.

The invention provides a heavy metal contaminated soil ex-situ remediation device and a remediation method; after being intensively excavated, the soil polluted by the heavy metal is temporarily stored, and is backfilled to the polluted area after being repaired by the repairing device and the repairing method; the repairing risk is reduced, the continuous operation of the repairing process is realized, and the repairing efficiency is improved.

The heavy metals in the polluted soil comprise Cu, Cd, Ni, Pb, Zn and the like; the applied electric field intensity is 1-3V/cm, the cathode and anode electric repair liquid is controlled to be at pH 3-5 because electroosmotic flow pH is larger than 3, the electroosmotic direction is ensured to flow from the anode to the cathode, and the heavy metal ion migration direction is also from the anode to the cathode, so that the heavy metal migration in the same direction is promoted, and the reason that the heavy metal migration is smaller than 5 is that the soil desorption effect is better under the acidic condition, the heavy metal is prevented from forming precipitates under the alkaline condition, and the heavy metal migration in the gap liquid is prevented.

In the pretreatment, the resolving solution in the first step is a citric acid solution with pH of 5-7, the pH is set to prevent that a large amount of Ca and Mg ions in the stone are dissolved out due to too low pH, and the electric repair effect is influenced, the complexing agent added in the second step is the citric acid solution with pH of 2-4, the pH is set to be H2L-formed due to the fact that the citric acid is H2L-formed at the pH, and can form (H2LA) + complex with bivalent heavy metal A2+, and the complex moves from the anode to the cathode, so that the heavy metal migration efficiency is improved;

in the electric repairing process, the pH buffer regulating solution is citric acid and sodium citrate with pH =3, and the electric repairing solution of the cathode and the anode is 0.1mol/L potassium nitrate.

The above; but are merely preferred embodiments of the invention; the scope of the invention is not limited thereto; any person skilled in the art is within the technical scope of the present disclosure; the technical scheme and the improved concept of the invention are equally replaced or changed; are intended to be covered by the scope of the present invention.

Claims

1. The utility model provides a prosthetic devices of heavy metal contaminated soil, includes coarse filtration device (1), its characterized in that: the device is characterized by also comprising a fine filtering device (2) and an electric repairing device (3), wherein the coarse filtering device (1), the fine filtering device (2) and the electric repairing device (3) are sequentially connected;

the coarse filtering device (1) comprises a round drum type stone remover (101) and a coarse filtering tank (102), the round drum type stone remover (101) is horizontally arranged, the lower part of the round drum type stone remover is immersed in the coarse filtering tank (102), analytic liquid is mixed in the coarse filtering tank (102), a plurality of small holes (103) are formed in the inner wall of the round drum type stone remover (101), and the bottom end of the coarse filtering tank (102) is connected with the fine filtering device (2) through a first pipeline (104);

the inner walls of the rough filter tank (102) at the two ends of the round drum type stoner (101) are provided with bearing tables (105) with the same curvature radius as that of the round drum type stoner (101), the bearing tables (105) bear the two ends of the round drum type stoner (101), the outer wall of the middle position of the round drum type stoner (101) is fixedly connected with a circle of driven gear (106), the rough filter tank (102) is provided with a first motor, and the first motor is connected with the driven gear (106) through a driving gear;

the fine filtering device (2) comprises a fine filtering tank (201), a gravel bin (202) and a vibrating screen (203), wherein the gravel bin (202) is connected to one side of the fine filtering tank (201), the vibrating screen (203) is rotatably connected with the top end of the fine filtering tank (201) on the side close to the gravel bin (202), a second motor (204) is connected to one end, far away from the gravel bin (202), of the fine filtering tank (201), the second motor (204) is connected with a triangular gear (205), and the vibrating screen (203) is located above the triangular gear (205);

the first pipeline (104) is positioned above one side of the vibrating screen (203) close to the second motor (204), the fine filter tank (201) is further provided with a complexing agent box (206), the bottom end of the fine filter tank (201) is connected with the coarse filter tank (102) through a circulating pipe (207), and the bottom end of the fine filter tank (201) is connected with the electric repair device (3) through a second pipeline (211).

2. The remediation device for heavy metal contaminated soil according to claim 1, wherein: vibrations screen cloth (203) top middle part be connected with third motor (208), third motor (208) be connected with pivot (209), pivot (209) run through vibrations screen cloth (203) and extend to inside thin filtering ponds (201), the side of pivot (209) is connected with a plurality of puddlers (210).

3. The remediation device for heavy metal contaminated soil according to claim 1, wherein: the electric repairing device (3) comprises an electric repairing pool (301), wherein a first anode electrode (302) is arranged at one end inside the electric repairing pool (301), a cathode electrode (303) is arranged at the opposite end, a plurality of second anode electrodes (304) are further arranged inside the electric repairing pool (301), a permeable reaction wall (305) is arranged on one side, close to the first anode electrode (302), of each of the second anode electrodes (304) and the cathode electrodes (303), the cathode electrode (303) is connected with a cathode of a power supply (306), and the first anode electrode (302) and the second anode electrode (304) are connected with an anode of the power supply (306) through a switch (307);

and third pipelines (308) are respectively arranged at the bottom ends between the first anode electrode (302) and the second anode electrode (304), between the second anode electrodes (304) and between the second anode electrode (304) and the cathode electrode (303), and the third pipelines (308) are respectively connected with a mud-water filter press.

4. The remediation device for heavy metal contaminated soil according to any one of claims 1 to 3, wherein the remediation method comprises:

firstly, placing soil to be repaired in a coarse filtration device (1) for coarse filtration to remove large stones;

secondly, the soil after coarse filtration enters a fine filtration device (2) for fine filtration to remove small gravel;

and thirdly, the finely filtered soil enters an electric restoration device (3) for electric restoration, and the purified soil is discharged.