In-situ electrokinetic remediation device for heavy metal polluted bottom mud

Abstract

The utility model belongs to the technical field of river and lake bottom mud remediation, and discloses a heavy metal polluted bottom mud in-situ electric remediation device which comprises a double-layer isolation cover, the cathode module is arranged at one end of the bottom of the double-layer isolation cover and comprises a cathode protection cover, the interior of the cathode protection cover is divided into a first cavity and a second cavity through a partition plate with holes, a cation exchange membrane and a cathode electrode are arranged in the first cavity, and a heavy metal adsorption material is arranged in the second cavity; the cathode module is arranged at the other end of the bottom of the double-layer isolation cover and comprises an anode protection cover, and an anode electrode is arranged in the anode protection cover; the cathode protection cover and the anode protection cover are made of insulating hard materials with holes, and the anode electrode and the cathode electrode are connected with a power source through waterproof wires respectively. And the electrolyte supply device is used for conveying acidic electrolyte to the cathode protection cover. The in-situ electrokinetic remediation device for the heavy metal polluted bottom mud is good in remediation effect.

Description

Technical Field

[0001] This utility model relates to river and lake bottom sediment remediation technology, and specifically to an in-situ electric remediation device for heavy metal contaminated bottom sediment. Background Technology

[0002] Seabed sediments are a vital component of aquatic ecosystems such as rivers and lakes, playing a crucial role in regulating nutrient cycling and ecological processes. Heavy metal pollutants enter the aquatic environment through atmospheric deposition, wastewater discharge, soil erosion, and rainfall. Some of these pollutants migrate into the sediment through complex interfacial exchanges and reactions, including adsorption, complexation, and precipitation, causing severe sediment pollution. Heavy metal pollution in sediments not only has direct toxic effects on benthic organisms but also, due to changes in environmental conditions, can potentially be released into the overlying water, causing secondary pollution, deteriorating water quality, posing drinking water safety issues, and directly or indirectly impacting human health through the food chain.

[0003] Sediment remediation technologies mainly include physical, chemical, and biological methods, or a combination of these methods. Among them, electrokinetic remediation technology utilizes two electrodes inserted into the soil to apply an electric field to both ends of the contaminated soil. Under the combined effects of electrochemical and electrokinetic processes, water-soluble or adsorbed pollutants on the surface of soil particles move towards the positive and negative electrodes according to their different charges, causing the pollutants to accumulate or be recycled near the electrodes, thereby achieving soil cleanup. Electrokinetic remediation technology is often used for heavy metal pollution remediation; however, it suffers from the problem of not being able to achieve true separation of pollutants. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the deficiencies and defects mentioned in the background art above, and to provide a device for in-situ remediation of heavy metal pollutants in sediment that can effectively achieve true separation of heavy metal pollutants and has high remediation efficiency.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is: an in-situ electric remediation device for heavy metal contaminated sediment, comprising: a double-layer isolation cover;

[0006] The cathode module is located at one end of the bottom of the double-layer isolation cover and includes a cathode protective cover. The cathode protective cover is divided into a first cavity and a second cavity by a perforated partition. The first cavity is equipped with a cation exchange membrane and a cathode electrode, and the second cavity is equipped with a heavy metal adsorption material.

[0007] An anode module, located at the other end of the bottom of a double-layered insulating cover, includes an anode protective cover, inside which an anode electrode is disposed; the cathode protective cover and the anode protective cover are made of perforated insulating rigid material, and the anode electrode and the cathode electrode are respectively connected to a power source via waterproof wires;

[0008] An electrolyte supply device is used to deliver acidic electrolyte to the cathode protection shield.

[0009] In one embodiment, the double-layer insulation cover includes an upper cover plate and a lower cover plate stacked and spaced apart, both of which have slots, and the upper and lower slots are staggered.

[0010] In one embodiment, both the cathode protection cover and the anode protection cover have hanging edges on their tops, and the lower cover plate has guide rails at corresponding positions, with the hanging edges connected to the guide rails.

[0011] In one embodiment, the bottom of both the cathode shield and the anode shield are formed with acute-angled tips.

[0012] In one embodiment, the cross-sections of the cathode shield and the anode shield are wedge-shaped, and the cathode shield and the anode shield are made of plexiglass.

[0013] In one embodiment, the electrolyte supply device includes an acidic electrolyte storage tank, an electrolyte outlet pipe, a delivery pump, and an electrolyte suction pipe. One end of the electrolyte outlet pipe is connected to the inside of the cathode protection shield, and the other end is connected to the delivery pump. The delivery pump and the acidic electrolyte storage tank are connected through the electrolyte suction pipe.

[0014] In one embodiment, the acidic electrolyte in the acidic electrolyte storage tank is 0.1M acetic acid.

[0015] In one embodiment, the infusion pump is a peristaltic pump, and the power supply is a DC regulated power supply.

[0016] Compared with existing technologies, the beneficial effects of this invention are as follows: In conventional electrokinetic remediation processes, OH- ions generated at the cathode migrate towards the anode, forming an alkaline migration zone. In the cathode region, OH- ions react with heavy metal ions to form hydroxide precipitates, which only allows pollutants to migrate directionally within a certain range and cannot achieve true separation of pollutants. In the in-situ electrokinetic remediation device for heavy metal-contaminated sediment of this application, a cation exchange membrane is installed in the cathode module to prevent the hydroxyl ions generated during electrolysis from migrating towards the anode, thus improving remediation efficiency. Furthermore, a heavy metal adsorption material is installed in the cathode module. Under the action of electrokinetic force, pollutants simultaneously migrate towards the heavy metal adsorption material that has migrated to the cathode module. After remediation, the adsorption material is removed to achieve in-situ removal of heavy metals, fundamentally solving the sediment pollution problem. An acidic electrolyte is pumped into the cathode module through an electrolyte supply device. This neutralizes the OH- ions generated during cathode electrolysis, promoting soil acidification, and also promotes the activation and dissociation of metals in the particles, effectively improving the efficiency of electrokinetic remediation. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of an in-situ electric remediation device for heavy metal contaminated sediment according to one embodiment.

[0019] Figure 2 A schematic diagram of the installation structure of an in-situ electric remediation device for heavy metal contaminated sediment, as one embodiment.

[0020] Figure 3 A schematic diagram of the cathode module structure of an in-situ electrodynamic remediation device for heavy metal contaminated sediment according to one embodiment.

[0021] Figure 4 This is a schematic diagram of the lower cover plate structure of an in-situ electric remediation device for heavy metal contaminated sediment, according to one embodiment.

[0022] In the diagram: 1: Cathode module, 2: Anode module, 3: Double-layer isolation cover, 4: Infusion pump, 5: Acidic electrolyte storage tank, 6: DC regulated power supply, 7: Waterproof wire, 1-1: Cathode protection cover, 1-3: Perforated partition, 1-5: Cathode electrode, 1-6: Heavy metal adsorption material, 1-7: Hanging edge, 2-1: Anode protection cover, 2-2: Anode electrode, 3-1: Upper cover plate, 3-2: Lower cover plate, 3-3: Slot, 3-4: Electrolyte outlet pipe mounting hole, 3-5: Cathode electrode waterproof wire mounting hole, 3-6: Anode electrode waterproof wire mounting hole, 3-7: Guide rail, 4-1: Electrolyte outlet pipe, 4-2: Electrolyte suction pipe. Detailed Implementation

[0023] To facilitate understanding of this utility model, the following description will be provided in more comprehensive and detailed manner with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.

[0024] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention.

[0025] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0026] like Figures 1-4 As shown, an embodiment of the in-situ electric remediation device for heavy metal contaminated sediment mainly includes a cathode module 1, an anode module 2, a double-layer isolation cover 3, an electrolyte supply device, a power supply 6, and a waterproof wire 7.

[0027] Specifically, in one embodiment, the cathode module 1 includes a cathode protection cover 1-1. The cathode protection cover 1-1 is divided into a first cavity and a second cavity by a perforated partition 1-3. The first cavity contains a cation exchange membrane and a cathode electrode 1-5, and the second cavity contains a heavy metal adsorption material 1-6. Preferably, the inner wall of the cathode protection cover 1-1 is provided with a filter cloth. The filter cloth can prevent bottom sediment from entering the cathode protection cover 1-1. Specifically, the cathode protection cover 1-1 is made of a perforated insulating rigid material, preferably an plexiglass plate. The cathode protection cover 1-1 and the double-layer insulating cover are detachably connected. Preferably, the top of the cathode protection cover 1-1 has a hanging edge 1-7 along its long side. Preferably, the bottom of the cathode protection cover 1-1 forms an acute-angled tip, which allows for better insertion into the bottom sediment. More preferably, the cross-section of the cathode protection cover 1-1 is wedge-shaped. A cation exchange membrane is disposed on one side of the wedge-shaped apex of the perforated partition 1-3 of the cathode shield 1-1, and a cathode electrode 1-5 is placed in the corresponding first cavity. The second cavity on the other side of the perforated partition 1-3 is filled with an adsorbent material 1-6 capable of adsorbing and remediating the target heavy metal. Specifically, the heavy metal adsorbent material 1-6 can generally be zeolite, bentonite, montmorillonite, or hydroxyapatite, etc. The cation exchange membrane can generally be a polystyrene-divinylphenyl membrane, a modified polyethylene membrane, etc.

[0028] Specifically, in one embodiment, the anode module 2 includes an anode protective cover 2-1, and the anode electrode 2-2 is disposed inside the anode protective cover 2-1. The anode protective cover 2-1 is made of a perforated rigid material, preferably an plexiglass plate. A hanging edge 1-7 is provided on the top of the anode protective cover 2-1 along its long side.

[0029] Specifically, in one embodiment, the double-layer isolation cover 3 consists of an upper cover plate 3-1 and a lower cover plate 3-2. The upper cover plate 3-1 and the lower cover plate 3-2 are two vertically placed, downward-opening U-shaped square plates. Several slots 3-3 are formed above the upper and lower cover plates, but the slots 3-3 are staggered and do not overlap. When the device is lowered, the upper cover plate 3-1 and the lower cover plate 3-2 are lowered separately to facilitate air escape during lowering. During repair, the two cover plates are stacked to isolate the bottom mud and the overlying water, thus providing insulation. When used in combination, the upper cover plate 3-1 and the lower cover plate 3-2 can achieve the purpose of isolating the overlying water and the bottom mud. The double-layer isolation cover 3 is pre-drilled with an electrolyte outlet pipe mounting hole 3-4, a cathode electrode waterproof wire mounting hole 3-5, and an anode electrode waterproof wire mounting hole 3-6. Preferably, a guide rail 3-7 is provided on the lower side of the lower cover plate 3-2 to cooperate with the hanging edge 1-7, and the hanging edge 1-7 is set on the guide rail 3-7.

[0030] Specifically, in one embodiment, the electrolyte supply device is used to deliver acidic electrolyte to the cathode protection shield 1-1. Specifically, the electrolyte supply device includes an acidic electrolyte storage tank 5, an electrolyte outlet pipe 4-1, a delivery pump 4, and an electrolyte suction pipe 4-2. One end of the electrolyte outlet pipe 4-1 is connected to the cathode protection shield 1-1, and the other end is connected to the delivery pump. The delivery pump 4 and the electrolyte storage tank 5 are connected via the electrolyte suction pipe 4-2. By inputting acidic electrolyte into the cathode module 1, the OH- ions generated by cathode electrolysis can be neutralized, promoting soil acidification and facilitating the activation and dissociation of metals in the particles, effectively improving the electroremediation efficiency.

[0031] Preferably, the infusion pump 4 is a peristaltic pump. In one embodiment, the acidic electrolyte is specifically 0.1M acetic acid.

[0032] Preferably, the power supply 6 is a DC regulated power supply, which is connected to the cathode electrode 1-5 in the cathode module 1 and the anode electrode 2-2 in the anode module 2 via waterproof wires 7.

[0033] One embodiment of the method for remediating sediment using an in-situ electrodynamic remediation device for heavy metal contaminated sediment:

[0034] 1) After connecting the waterproof wire 7 to the cathode electrode 1-5 and the anode electrode 2-2 respectively, it passes upward through the corresponding waterproof wire mounting holes 3-5 and 3-6 reserved in the double-layer isolation cover 3 for the cathode electrode and the anode electrode respectively.

[0035] 2) Connect the hanging edge 1-7 of the top of the cathode protection cover 1-1 and the anode protection cover 2-1 along the long side direction to the guide rail of the lower cover plate;

[0036] 3) Insert the electrolyte outlet pipe 4-1 of the peristaltic pump into the cathode protection cover 1-1 through the electrolyte outlet pipe mounting hole 3-4 reserved in the double-layer isolation cover 3;

[0037] 4) Insert the cathode module 1 and anode module 2 vertically into the bottom sediment. In this embodiment, the bottom sediment is contaminated with heavy metal Cd. The lower cover plate 3-2 is located at the mud-water interface.

[0038] 5) Lower the upper cover plate 3-1 along the waterproof guide wire 7 and the peristaltic pump electrolyte outlet pipe 4-1 above the lower cover plate 3-2 to complete the installation of the double-layer isolation cover 3;

[0039] 6) Connect the waterproof wire 7 to the power supply 6; connect the peristaltic pump and the acidic electrolyte storage tank 5 containing the acidic electrolyte through the electrolyte suction pipe 4-2, and start the peristaltic pump. Under the action of the DC electric field, the heavy metal cations in the contaminated sediment inside the electrode system migrate to the cathode and accumulate in the adsorption material 1-6 of the cathode module, thereby reducing the content of harmful heavy metal ions in the sediment and achieving the purpose of sediment remediation.

[0040] In the above embodiments, the total cadmium content of a certain contaminated sediment before remediation was 7.1 mg / kg, the electric field strength was 2 V / cm, the remediation material was hydroxyapatite, the cation exchange membrane was a modified polyethylene membrane, and the content after remediation was 1.9 mg / kg, with a remediation rate of 73.2%.

[0041] In the comparative example, a set of electrodes with the same material and shape as those in the example were vertically placed in the sediment. After the electrodes were energized, the electric field strength was 2V / cm. The cadmium concentration in the sediment after repair was 5.0mg / kg, and the repair rate was only 29.6%.

[0042] The above are merely preferred embodiments of this utility model. It should be noted that this utility model is not limited to the above embodiments. For those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. An in-situ electrically powered remediation device for heavy metal contaminated sediment, characterized in that, include: Double-layer insulation shield; The cathode module is located at one end of the bottom of the double-layer isolation cover and includes a cathode protective cover. The cathode protective cover is divided into a first cavity and a second cavity by a perforated partition. The first cavity is equipped with a cation exchange membrane and a cathode electrode, and the second cavity is equipped with a heavy metal adsorption material. An anode module is located at the other end of the bottom of the double-layer insulation cover, including an anode protective cover, inside which an anode electrode is provided; The cathode and anode protective covers are made of perforated insulating rigid material, and the anode and cathode electrodes are respectively connected to the power supply via waterproof wires; An electrolyte supply device is used to deliver acidic electrolyte to the cathode protection shield.

2. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 1, characterized in that, The double-layer isolation cover includes an upper cover plate and a lower cover plate stacked and spaced apart. Both the upper cover plate and the lower cover plate have slots, and the upper and lower slots are staggered.

3. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 2, characterized in that, Both the cathode protection cover and the anode protection cover have hanging edges on their tops, and the lower cover plate has guide rails at corresponding positions, with the hanging edges connected to the guide rails.

4. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 1, characterized in that, Both the cathode and anode protective covers have acute-angled tips at their bottoms.

5. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 4, characterized in that, The cathode and anode protective covers have wedge-shaped cross-sections and are made of plexiglass.

6. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 1, characterized in that, The electrolyte supply device includes an acidic electrolyte storage tank, an electrolyte outlet pipe, a delivery pump, and an electrolyte suction pipe. One end of the electrolyte outlet pipe is connected to the inside of the cathode protection shield, and the other end is connected to the delivery pump. The delivery pump and the acidic electrolyte storage tank are connected through the electrolyte suction pipe.

7. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 6, characterized in that, The acidic electrolyte in the acidic electrolyte storage tank is 0.1M acetic acid.

8. The in-situ electrodynamic remediation device for heavy metal contaminated sediment according to claim 6, characterized in that, The infusion pump is a peristaltic pump, and the power supply is a DC regulated power supply.

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