Attapulgite-based permeable reactive barriers and methods for remediating sites contaminated with halohydrocarbons

Abstract

This invention provides an attapulgite-based permeable reactive barrier and method for remediating sites contaminated with halogenated hydrocarbons, belonging to the field of groundwater treatment technology. It includes a reactive barrier main body perpendicular to the water flow direction, a front guide wall located at the water inlet of the reactive barrier main body, a rear guide wall located at the water outlet of the reactive barrier main body and symmetrically distributed with the front guide wall, and several attapulgite filter media modules installed on the reactive barrier main body. A first and second mounting frame with a wave-shaped structure can extend the water flow path, increasing the contact time between pollutants and the attapulgite filter media modules. Simultaneously, a second mounting frame is provided on the outlet side of each first mounting frame, and the second mounting frame is equipped with a rotating mounting frame for installing the attapulgite filter media modules. This allows the water to flow through the reactive barrier main body more quickly by rotating the mounting frame, ensuring purification effect while improving the overall treatment efficiency of the permeable reactive barrier.

Description

Technical Field

[0001] This invention belongs to the field of groundwater treatment technology, specifically to the attapulgite-based permeable reactive barrier and method for remediating sites contaminated with halogenated hydrocarbons. Background Technology

[0002] Human society's survival and development are inseparable from water resources, among which groundwater is one of the most important resources currently available to humankind. Groundwater resources are characterized by excellent water quality and wide distribution, thus serving as a commonly used water source, with enormous demand for groundwater in agricultural irrigation and daily life. However, in modern times, due to the rapid development and disorderly expansion of petrochemical production and the excessive use of pesticides, more and more groundwater has become polluted, rendering it unusable.

[0003] Chlorinated hydrocarbons are widely used in the chemical industry and are currently the most polluting type of volatile organic pollutant to groundwater and soil. They are highly volatile, difficult to degrade under natural conditions, and produce a variety of products during degradation, most of which are also highly hazardous.

[0004] Traditional remediation techniques (such as extraction and chemical oxidation) suffer from drawbacks such as high cost and the potential for secondary pollution, while permeable reactive barrier technology has garnered widespread attention due to its passive remediation characteristics. However, existing permeable reactive barrier technologies still have the following problems:

[0005] First, fluctuations in groundwater flow velocity or sudden impacts can easily lead to deformation of the reactive barrier structure or loss of filler material, making it difficult to guarantee repair efficiency.

[0006] Second, traditional fixed filter media is difficult to replace, requiring frequent excavation and repair, which increases operation and maintenance costs.

[0007] Third, single packing materials (such as zero-valent iron) mainly rely on reduction dechlorination, and their ability to synergistically treat multi-component halogenated hydrocarbons and co-pollutants is insufficient. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides an attapulgite-based permeable reactive barrier and method for remediating sites contaminated with halogenated hydrocarbons.

[0009] The technical solution of the present invention is: an attapulgite-based permeable reactive wall for remediating sites contaminated with halogenated hydrocarbons, comprising a reactive wall body distributed perpendicular to the water flow direction, a front guide wall located at the water inlet of the reactive wall body, a rear guide wall located at the water outlet of the reactive wall body and symmetrically distributed with the front guide wall, and several attapulgite filter media modules installed on the reactive wall body.

[0010] The main body of the reactive wall includes horizontal mounting plates distributed parallel to the front and rear sides of the riverbank, several first mounting frames and several second mounting frames vertically installed between the two horizontal mounting plates and distributed parallel to each other, and the first mounting frames and the second mounting frames are staggered.

[0011] The first mounting frame is composed of several first mounting frames arranged in a staggered manner to form a wave-like structure, and the side wall of the first mounting frame is provided with a first snap-fit ​​notch. The second mounting frame is composed of several second mounting frames arranged in a staggered manner to form a wave-like structure, and the tilt angle of each second mounting frame on the same second mounting frame is symmetrically distributed with the tilt angle of each first mounting frame on the adjacent first mounting frame. A rotating mounting frame is connected to the second mounting frame through a rotating shaft, and the side wall of the rotating mounting frame is provided with a second snap-fit ​​notch.

[0012] Several of the aforementioned attapulgite filter media modules are respectively installed at each of the first snap-fit ​​notches and each of the second snap-fit ​​notches.

[0013] Furthermore, a sedimentation well is provided at the water inlet of the main body of the reaction wall and at the lower end of the front guide wall. The inner wall of the sedimentation well is provided with several vertically arranged aeration pipes, and each aeration pipe is provided with several microporous aeration heads.

[0014] Explanation: The purpose of the sedimentation well is to collect sediment from the bottom of the water body, preventing it from directly entering the main body of the reactive barrier and clogging the attapulgite filter media module, thus affecting permeability. At the same time, an aeration pipe with microporous aeration heads is installed on the inner wall of the sedimentation well. Compressed air is released from the bottom to generate rising air bubbles, driving the water in the sedimentation well to generate vertical convection circulation, thereby achieving effective mixing of sediment water and surface water. This can maintain the aerobic state of the water in the sedimentation well, inhibit the activity of anaerobic microorganisms, and reduce the generation of odors and the secondary release of pollutants.

[0015] Furthermore, the two horizontal mounting plates are respectively provided with buffer sliding openings on opposite sides, corresponding one-to-one with the first mounting frame and the second mounting frame. The two first mounting frames located at the ends of the first mounting frame are slidably connected to the corresponding buffer sliding openings, and the two second mounting frames located at the ends of the second mounting frame are slidably connected to the corresponding buffer sliding openings.

[0016] Explanation: When water flows into the main body of the reactive wall, under the impact of the water flow, each of the first and second mounting brackets can slide slightly in the corresponding buffer sliding openings on the horizontal mounting plate. This disperses and buffers the impact of the water flow, reducing the direct impact on the first and second mounting brackets, reducing the vibration and deformation of the structure caused by the water flow impact, improving the stability and safety of the first and second mounting brackets, enabling the main body of the reactive wall to work normally under different water flow conditions, and improving the project's adaptability to complex water flow environments.

[0017] Furthermore, each of the second mounting frames located on the same second mounting bracket and spaced apart is connected to the first mounting frames adjacent to it on the left and right sides by a buffer support rod.

[0018] Explanation: By slightly sliding and dispersing the impact of water flow within the corresponding buffer sliding openings on the horizontal mounting plate through the first and second mounting brackets, and by providing elastic support between the first and second mounting frames through the buffer support rods, part of the impact force of water flow can be absorbed and dissipated, thereby improving the seismic resistance of the permeable reactive wall under the impact of water flow.

[0019] Furthermore, the attapulgite filter media module includes two snap-fit ​​frames that are relatively distributed and hinged at their bottom ends, an elastic metal mesh installed on the side wall of the snap-fit ​​frames, and an attapulgite filter media bag placed between the two snap-fit ​​frames, with the upper ends of the two snap-fit ​​frames snapped together.

[0020] Description: Two interlocking frames, hinged at the bottom and fastened at the top, serve as external support components. Elastic metal mesh is installed on the side walls of each frame. The attapulgite filter media pack is placed within the space between the two frames. When water flows through the attapulgite filter media pack, the two frames protect it, effectively preventing the filter media from being washed away by the water flow. Simultaneously, the elastic metal mesh can deform elastically to some extent with changes in water pressure, while the interlocking frames ensure the stability of the overall structure, effectively protecting the attapulgite filter media pack under different operating conditions.

[0021] Furthermore, the surface of the attapulgite filter media bag is covered with a corrosion-resistant mesh, and the material of the attapulgite filter media bag is a mixture of attapulgite, nano-zero valent iron and activated carbon in a mass ratio of 4:2:1.

[0022] Note: The corrosion-resistant mesh covering the surface protects the attapulgite, nano-zero ferric iron, and activated carbon inside the attapulgite filter media pack, further preventing them from being lost or becoming ineffective due to water erosion, chemical corrosion, and other factors during long-term use. At the same time, attapulgite, nano-zero ferric iron, and activated carbon are all environmentally friendly materials. During use, they can adsorb organic matter and some halogenated hydrocarbons in the water without producing secondary pollution, making them environmentally friendly.

[0023] Furthermore, the cross-sections of the front guide wall and the rear guide wall are trapezoidal or arc-shaped, and the angle between the inclined surfaces of the front guide wall and the water flow direction is 30°-60°. The front guide wall and the rear guide wall are both provided with inclined perforated guide plates inside, and the diameter of the holes in the perforated guide plates is 5-10mm, which further disperses the water flow impact force.

[0024] Explanation: By limiting the angle between the inclined surfaces of the front and rear guide walls and the direction of water flow to 30°-60°, turbulence is reduced and water flow is evenly distributed. The porous guide plate can further disperse the impact force of the water flow, reduce local stress concentration, and prevent the front and rear guide walls from cracking or deforming.

[0025] A method for remediating sites contaminated with halogenated hydrocarbons, based on the aforementioned attapulgite-based permeable reactive barrier for remediating halogenated hydrocarbon-contaminated sites, includes the following steps:

[0026] S1. The polluted water at the halogenated hydrocarbon contaminated site flows through the front guide wall, which guides the flow of the polluted water into the main body of the reaction wall.

[0027] S2. The polluted water first flows through the first first installation frame, and the organic matter and some halogenated hydrocarbons in the polluted water are first adsorbed and degraded by the attapulgite filter media modules installed on each first installation frame, which are distributed end to end and form a wave-shaped structure.

[0028] S3. After the water body has completed the first adsorption and degradation, it flows through the first second installation frame and passes through several second installation frames that are staggered and form a wave-shaped structure. Under the action of the water flow impact force, the rotating installation frame will rotate. On the one hand, the attapulgite filter media module on the rotating installation frame adsorbs and degrades organic matter and some halogenated hydrocarbons in the local water body. On the other hand, the water flow rate can be accelerated by rotating the installation frame.

[0029] S4. After the water passes through the first second mounting frame, it enters the second first mounting frame again, and passes through the attapulgite filter media modules installed on each of the first mounting frames, which are staggered and form a wave-like structure, to perform a second adsorption and degradation of organic matter and some halogenated hydrocarbons in the water. After the water has completed the second adsorption and degradation, it flows through the second second mounting frame and repeats the content of step S3. While adsorbing and degrading organic matter and some halogenated hydrocarbons in the local water, the water flows into the third first mounting frame more quickly.

[0030] S5. Repeat step S4 until the water flows through the last first mounting frame. After several adsorption and degradation of organic matter and some halogenated hydrocarbons in the water, the water flows out through the last second mounting frame and the outflow of the water is guided.

[0031] Furthermore, in steps S2-S5, the convex and concave rod filter media modules at each of the first snap-fit ​​notches and each of the second snap-fit ​​notches are replaced every 4-5 months.

[0032] Note: Regularly replacing the attapulgite filter media module can ensure that the reaction wall always maintains good filtration and adsorption effects, improve the removal capacity of pollutants such as halogenated hydrocarbons, and ensure that the effluent water quality consistently meets standards.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] The attapulgite-based permeable reactive barrier of this invention for remediating sites contaminated with halogenated hydrocarbons utilizes a wave-shaped first and second mounting frame to extend the water flow path, increasing the contact time between pollutants and the attapulgite filter media modules. The attapulgite filter media modules are connected to the first and second mounting frames via a snap-fit ​​mechanism, shortening replacement time and improving work efficiency. Simultaneously, a second mounting frame is provided on the outlet side of each first mounting frame, with a rotating mounting frame for installing the attapulgite filter media modules. This allows water to flow through the reactive barrier body more quickly, ensuring purification while improving the overall treatment efficiency of the permeable reactive barrier. The first and second mounting frames within the reactive barrier body, through a buffer sliding port design, effectively disperse and buffer the impact of the water flow, reducing direct impact on the first and second mounting frames and minimizing structural vibration and deformation caused by water flow impact. Furthermore, the buffer support rod provides elastic support between the first and second mounting frames, absorbing and dissipating some of the water flow impact force, thus improving the permeable reactive barrier's seismic resistance under water flow impact. Attached Figure Description

[0035] Figure 1 This is the first top view of the present invention;

[0036] Figure 2 This is a second top view of the present invention;

[0037] Figure 3 This is a schematic diagram of the structure of the first mounting bracket of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the first mounting bracket during the installation of the attapulgite filter media module of the present invention;

[0039] Figure 5 This is a schematic diagram of the structure of the second mounting bracket of the present invention;

[0040] Figure 6 This is a schematic diagram of the structure of the second mounting bracket during the installation of the attapulgite filter media module of the present invention;

[0041] Figure 7 This is a schematic diagram of a partial connection structure between the first and second mounting brackets and the horizontal mounting plate of the present invention;

[0042] Figure 8 This is a side view of the attapulgite filter media module of the present invention;

[0043] Figure 9 This is a schematic diagram of the fastening frame of the present invention.

[0044] Among them, 1-reaction wall main body, 10-horizontal mounting plate, 11-first mounting bracket, 110-first mounting frame, 111-first snap-fit ​​notch, 12-second mounting bracket, 120-second mounting frame, 121-rotating shaft, 122-rotating mounting frame, 123-second snap-fit ​​notch, 124-buffer support rod, 13-sedimentation injection well, 130-aeration pipe, 131-microporous aeration head, 14-buffer sliding port, 2-front guide wall, 3-rear guide wall, 4-attapulgite filter media module, 40-fastening frame, 41-elastic metal mesh, 42-attapulgite filter media bag, 5-porous guide plate. Detailed Implementation

[0045] To further understand the content of the present invention, the present invention will be described in detail below through embodiments.

[0046] Example 1: As Figure 1 , 2 As shown, the attapulgite-based permeable reactive wall for remediating a site contaminated with halogenated hydrocarbons includes a reactive wall body 1 distributed perpendicular to the water flow direction, a front guide wall 2 located at the water inlet of the reactive wall body 1, a rear guide wall 3 located at the water outlet of the reactive wall body 1 and symmetrically distributed with the front guide wall 2, and several attapulgite filter media modules 4 installed on the reactive wall body 1.

[0047] The main body of the reaction wall 1 includes horizontal mounting plates 10 distributed parallel to the front and rear sides of the riverbank, four first mounting frames 11 and four second mounting frames 12 vertically installed between the two horizontal mounting plates 10 and distributed parallel to each other, and the first mounting frames 11 and the second mounting frames 12 are staggered.

[0048] like Figure 3 , 4 As shown in Figures 5 and 6, the first mounting frame 11 is composed of six first mounting frames 110 arranged in a staggered manner and forming a wave-shaped structure. The side wall of the first mounting frame 110 is provided with a first snap-fit ​​notch 111. The second mounting frame 12 is composed of six second mounting frames 120 arranged in a staggered manner and forming a wave-shaped structure. The tilt angle of each second mounting frame 120 on the same second mounting frame 12 is symmetrically distributed with the tilt angle of each first mounting frame 110 on the adjacent first mounting frame 11. A rotating mounting frame 122 is connected to the second mounting frame 120 through a rotating shaft 121. The side wall of the rotating mounting frame 122 is provided with a second snap-fit ​​notch 123.

[0049] Several convex and concave rod filter media modules 4 are respectively installed at each of the first snap-fit ​​notch 111 and each of the second snap-fit ​​notch 123;

[0050] like Figure 8 , 9 As shown, the attapulgite filter media module 4 includes two interlocking frames 40 that are relatively distributed and hinged at their bottom ends, an elastic metal mesh 41 installed on the side wall of the interlocking frames 40, and an attapulgite filter media bag 42 placed between the two interlocking frames 40. The upper ends of the two interlocking frames 40 are interlocked with each other. The two interlocking frames 40, which are hinged at their bottom ends and interlocked at their upper ends, serve as external support members. The elastic metal mesh 41 is installed on the side wall of each interlocking frame 40. The attapulgite filter media bag 42 is placed in the space between the two interlocking frames 40. When water flows through the attapulgite filter media bag 42 for treatment, the two interlocking frames 40 can protect the internal attapulgite filter media bag 42, which can effectively prevent the filter media from being washed away by the water flow. At the same time, the elastic metal mesh 41 can generate elastic deformation to a certain extent with the change of water pressure. Meanwhile, the interlocking frames 40 ensure the stability of the overall structure, so as to effectively protect the attapulgite filter media bag 42 under different working conditions.

[0051] The surface of the attapulgite filter media bag 42 is covered with a corrosion-resistant mesh. The material of the attapulgite filter media bag 42 is a mixture of attapulgite, nano-zero-valent iron, and activated carbon in a mass ratio of 4:2:1. The corrosion-resistant mesh covering the surface can protect the attapulgite, nano-zero-valent iron, and activated carbon inside the attapulgite filter media bag 42, further preventing them from being lost or becoming ineffective due to factors such as water flow erosion and chemical corrosion during long-term use. At the same time, attapulgite, nano-zero-valent iron, and activated carbon are all environmentally friendly materials. During use, they can adsorb organic matter and some halogenated hydrocarbons in the water without producing secondary pollution, making them environmentally friendly.

[0052] Example 2: This example discloses a method for remediating sites contaminated with halohydrocarbons, based on the attapulgite-based permeable reactive barrier used in Example 1 for remediating sites contaminated with halohydrocarbons, including the following steps:

[0053] S1. The polluted water at the halogenated hydrocarbon contaminated site flows through the front guide wall 2 and is guided by the front guide wall 2 to flow into the main body of the reaction wall 1.

[0054] S2. The polluted water first flows through the first first mounting frame 11, and the organic matter and some halogenated hydrocarbons in the polluted water are first adsorbed and degraded by the attapulgite filter media modules 4 installed on each first mounting frame 110 that are staggered and form a wave-shaped structure.

[0055] S3. When the water that has completed the first adsorption and degradation flows through the first second mounting frame 12 and passes through the six second mounting frames 120 that are staggered and form a wave-like structure, the rotating mounting frame 122 will rotate under the impact of the water flow. On the one hand, the attapulgite filter media module 4 on the rotating mounting frame 122 adsorbs and degrades organic matter and some halogenated hydrocarbons in the local water. On the other hand, the water flow rate can be accelerated by rotating the mounting frame 122.

[0056] S4. After the water passes through the first second mounting frame 12, it enters the second first mounting frame 11 again, and passes through the attapulgite filter media modules 4 installed on each first mounting frame 110, which are staggered and form a wave-shaped structure, to perform a second adsorption and degradation of organic matter and some halogenated hydrocarbons in the water. After the water has completed the second adsorption and degradation, it flows through the second second mounting frame 12 and repeats the content of step S3. While adsorbing and degrading organic matter and some halogenated hydrocarbons in the local water, the water flows into the third first mounting frame 11 at an accelerated rate.

[0057] S5. Repeat step S4 until the water flows through the last first mounting frame 11. After several adsorption and degradation of organic matter and some halogenated hydrocarbons in the water, the water flows out through the last second mounting frame 12 and the outflow of the water is guided.

[0058] In steps S2-S5, the convex-concave filter media modules 4 at each of the first snap-fit ​​notches 111 and each of the second snap-fit ​​notches 123 are replaced every 4 months.

[0059] Example 3: This example differs from Example 1 in that:

[0060] like Figure 1 , 2 As shown, a sedimentation well 13 is located at the water inlet of the main body 1 of the reaction wall and directly below the front guide wall 2. The inner wall of the sedimentation well 13 has five vertically arranged aeration pipes 130, each equipped with eight microporous aeration heads 131. The function of the sedimentation well 13 is to collect sediment from the bottom of the water body, preventing it from directly entering the main body 1 of the reaction wall and clogging the attapulgite filter media module 4, thus affecting permeability. Simultaneously, the aeration pipes 130 with microporous aeration heads 131 on the inner wall of the sedimentation well 13 generate rising air bubbles by releasing compressed air from the bottom, driving vertical convection circulation of the water in the sedimentation well to achieve effective mixing of the sedimented water and surface water, thus maintaining the sedimentation well's stability. The aerobic state of the water in well 13 inhibits the activity of anaerobic microorganisms, reduces odor generation and secondary release of pollutants. The aeration pipe 130 and the microporous aeration head 131 both adopt existing technologies. For example, the aeration pipe 130 can be made of existing UPVC pipe, ABS pipe, stainless steel pipe, etc., and the microporous aeration head 131 can be a 215 type diaphragm microporous aeration head. In actual application, the air is usually supplied by an external blower and compressed air is released into the sedimentation well 13 through the aeration pipe 130 and the microporous aeration head 131. The blower can use existing power supply methods, such as external power supply or solar power equipment, as long as the usage requirements are met, which will not be elaborated here.

[0061] Example 4: This example differs from Example 2 in that:

[0062] In step 1, the polluted water at the halogenated hydrocarbon contaminated site collects sediment at the bottom of the water body through the sedimentation well 13. At the same time, an aeration pipe 130 with microporous aeration heads 131 is installed on the inner wall of the sedimentation well 13. Compressed air is released from the bottom to generate rising bubble flow, which drives the water in the sedimentation well to generate vertical convection circulation to achieve effective mixing of sediment water and surface water.

[0063] Example 5: This example differs from Example 3 in that:

[0064] like Figure 7As shown, the two horizontal mounting plates 10 are respectively provided with buffer sliding openings 14 on opposite sides, corresponding one-to-one with the first mounting frame 11 and the second mounting frame 12. The two first mounting frames 110 located at the ends of the first mounting frame 11 are slidably connected to the corresponding buffer sliding openings 14, and the two second mounting frames 120 located at the ends of the second mounting frame 12 are slidably connected to the corresponding buffer sliding openings 14.

[0065] Each second mounting frame 120, located on the same second mounting bracket 12 and spaced apart, is connected to the adjacent first mounting frames 110 on the left and right sides by buffer support rods 124. While the first mounting brackets 11 and the second mounting brackets 12 slide slightly in the corresponding buffer sliding openings 14 on the horizontal mounting plate 10 to buffer the impact of water flow, the buffer support rods 124 also provide elastic support between the first mounting frames 110 and the second mounting frames 120. This can absorb and dissipate part of the impact of water flow and improve the seismic resistance of the permeable reactive wall under the impact of water flow.

[0066] Example 6: This example differs from Example 4 in that:

[0067] In steps 2-4, when water flows into the main body 1 of the reaction wall, under the impact of the water flow, each of the first mounting brackets 11 and each of the second mounting brackets 12 can slide slightly in the corresponding buffer sliding port 14 on the horizontal mounting plate 10, so that the impact force of the water flow is dispersed and buffered. In addition, the buffer support rod 124 provides elastic support between the first mounting frame 110 and the second mounting frame 120, which can absorb and dissipate part of the impact force of the water flow.

[0068] Example 7: This example differs from Example 5 in that:

[0069] like Figure 1 , 2 As shown, the cross-sections of the front guide wall 2 and the rear guide wall 3 are trapezoidal or arc-shaped. The angle between the inclined surface of the front guide wall 2 and the rear guide wall 3 and the direction of water flow is 30°. The front guide wall 2 and the rear guide wall 3 are both equipped with inclined perforated guide plates 5. The diameter of the holes in the perforated guide plates 5 is 5mm, which further disperses the impact force of the water flow.

[0070] Example 8: This example differs from Example 7 in that:

[0071] The front guide wall 2 and the rear guide wall 3 have trapezoidal or arc-shaped cross sections. The angle between the inclined surface of the front guide wall 2 and the rear guide wall 3 and the direction of water flow is 60°. The front guide wall 2 and the rear guide wall 3 are equipped with inclined perforated guide plates 5. The diameter of the holes in the perforated guide plates 5 is 10mm, which further disperses the impact force of the water flow.

[0072] Example 9: This example differs from Example 6 in that:

[0073] In step 1, the angle between the inclined surfaces of the front guide wall 2 and the rear guide wall 3 and the direction of water flow is defined to reduce turbulence and distribute the water flow evenly. The porous guide plate 5 can further disperse the impact force of the water flow.

[0074] Example 10: This example differs from Example 9 in that:

[0075] In steps S2-S5, the convex-concave filter media modules 4 at each of the first snap-fit ​​notches 111 and each of the second snap-fit ​​notches 123 are replaced every 5 months.

Claims

1. An attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons, characterized in that, It includes a reaction wall body (1) that is perpendicular to the direction of water flow, a front guide wall (2) located at the water inlet of the reaction wall body (1), a rear guide wall (3) located at the water outlet of the reaction wall body (1) and symmetrically distributed with the front guide wall (2), and several attapulgite filter media modules (4) installed on the reaction wall body (1). The main body of the reactive wall (1) includes horizontal mounting plates (10) distributed parallel to the front and rear sides of the riverbank, several first mounting frames (11) and several second mounting frames (12) vertically installed between the two horizontal mounting plates (10) and distributed parallel to each other, and the first mounting frames (11) and the second mounting frames (12) are staggered. The first mounting frame (11) is composed of several first mounting frames (110) arranged in a staggered manner and forming a wave-shaped structure. The side wall of the first mounting frame (110) is provided with a first snap-fit ​​notch (111). The second mounting frame (12) is composed of several second mounting frames (120) arranged in a staggered manner and forming a wave-shaped structure. The tilt angle of each second mounting frame (120) on the same second mounting frame (12) is symmetrically distributed with the tilt angle of each first mounting frame (110) on the adjacent first mounting frame (11). A rotating mounting frame (122) is connected inside the second mounting frame (120) through a rotating shaft (121). The side wall of the rotating mounting frame (122) is provided with a second snap-fit ​​notch (123). Several of the aforementioned attapulgite filter media modules (4) are respectively installed at each of the first snap-fit ​​notches (111) and each of the second snap-fit ​​notches (123).

2. The attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons according to claim 1, characterized in that, The main body of the reaction wall (1) has a water inlet and a sedimentation well (13) located at the lower end of the front guide wall (2). The inner wall of the sedimentation well (13) has several vertically arranged aeration pipes (130), and each aeration pipe (130) has several microporous aeration heads (131).

3. The attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons according to claim 1, characterized in that, The two horizontal mounting plates (10) are respectively provided with buffer sliding openings (14) corresponding to the first mounting frame (11) and the second mounting frame (12) on opposite sides. The two first mounting frames (110) located at the ends of the first mounting frame (11) are slidably connected to the corresponding buffer sliding openings (14), and the two second mounting frames (120) located at the ends of the second mounting frame (12) are slidably connected to the corresponding buffer sliding openings (14).

4. The attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons according to claim 3, characterized in that, Each of the second mounting frames (120) located on the same second mounting bracket (12) and spaced apart is connected to the first mounting frames (110) on the left and right sides by buffer support rods (124).

5. The attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons according to claim 1, characterized in that, The attapulgite filter media module (4) includes two snap-fit ​​frames (40) that are relatively distributed and hinged at the bottom, an elastic metal mesh (41) installed on the side wall of the snap-fit ​​frame (40), and an attapulgite filter media bag (42) placed between the two snap-fit ​​frames (40). The upper ends of the two snap-fit ​​frames (40) are snapped together.

6. The attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons according to claim 5, characterized in that, The surface of the attapulgite filter media bag (42) is covered with a corrosion-resistant mesh. The material of the attapulgite filter media bag (42) is a mixture of attapulgite, nano-zero valent iron and activated carbon in a mass ratio of 4:2:

1.

7. The attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons according to claim 1, characterized in that, The cross-sections of the front guide wall (2) and the rear guide wall (3) are trapezoidal or arc-shaped, and the angle between their inclined surfaces and the direction of water flow is 30°-60°. The front guide wall (2) and the rear guide wall (3) are both provided with inclined perforated guide plates (5), and the diameter of the holes in the perforated guide plates (5) is 5-10mm.

8. A method for remediating sites contaminated with halohydrocarbons, based on the attapulgite-based permeable reactive barrier for remediating sites contaminated with halohydrocarbons as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. The polluted water at the halogenated hydrocarbon contamination site flows through the front guide wall (2) and is guided to flow into the main body of the reaction wall (1). S2. The polluted water first flows through the first first mounting frame (11), and the attapulgite filter media module (4) installed on each first mounting frame (110) with staggered end distribution and forming a wave-shaped structure performs the first adsorption and degradation of organic matter and some halogenated hydrocarbons in the polluted water. S3. When the water that has completed the first adsorption and degradation flows through the first second mounting frame (12) and passes through several second mounting frames (120) that are staggered and form a wave-like structure, the rotating mounting frame (122) will rotate under the action of the water flow impact force. On the one hand, the attapulgite filter media module (4) on the rotating mounting frame (122) adsorbs and degrades organic matter and some halogenated hydrocarbons in the local water. On the other hand, the water flow rate can be accelerated by rotating the mounting frame (122). S4. After the water passes through the first second mounting frame (12), it enters the second first mounting frame (11) again, and passes through the attapulgite filter media modules (4) installed on each first mounting frame (110) which are staggered and form a wave-shaped structure to perform a second adsorption and degradation of organic matter and some halogenated hydrocarbons in the water. After the water has completed the second adsorption and degradation, it flows through the second second mounting frame (12) and repeats the content of step S3. While adsorbing and degrading organic matter and some halogenated hydrocarbons in the local water, it accelerates the flow of water into the third first mounting frame (11). S5. Repeat step S4 until the water flows through the last first mounting frame (11). After several adsorption and degradation of organic matter and some halogenated hydrocarbons in the water, the water flows out through the last second mounting frame (12) and the outflow of the water can be guided.

9. A method for remediating a site contaminated with halohydrocarbons according to claim 8, characterized in that, In steps S2-S5, the convex-concave filter media modules (4) at each of the first snap-fit ​​notches (111) and each of the second snap-fit ​​notches (123) are replaced every 4-5 months.

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