Device for heavy metal precipitation and solidification test of river and lake sediment

Abstract

The present application belongs to the technical field of ecological remediation of heavy metals in bottom mud, and discloses a device for heavy metal precipitation and solidification test of river and lake bottom mud, which comprises a test tank body, a power supply, a pressing plate, a backwater tank body and an EKG drainage plate, the inner side of the test tank body is provided with a filter screen and a geotextile, the pressing plate and the backwater tank body are provided with EKG plate hole grooves, the EKG drainage plate comprises a cathode and an anode, the EKG drainage plate is provided with a liquid inlet, the test tank body is connected with a water outlet pump and a liquid storage tank, the water outlet pump is connected with a water outlet pipe, the liquid storage tank is communicated with a liquid guide pipe and a liquid inlet pump, and the liquid inlet pump is connected with a liquid inlet pipe; the present application realizes the precipitation and solidification of heavy metals in bottom mud and the continuous drainage of bottom mud by electro-osmosis combined with pre-pressing and heavy metal chelating agents, shortens the precipitation period of heavy metal pollutants and the solidification period of bottom mud, and realizes the efficient precipitation and solidification of heavy metal pollutants in river and lake bottom mud.

Description

Technical Field

[0001] This invention relates to the field of ecological restoration technology for heavy metals in sediment, specifically to a device for testing the precipitation and solidification of heavy metals in river and lake sediment. Background Technology

[0002] Sediment, a mixture of silt, clay, organic matter, and various minerals, is deposited at the bottom of water bodies through a series of physical, chemical, biological, and water transport processes. Large amounts of wastewater from electroplating, mining, and chemical industries are discharged into rivers and lakes. Over long periods, this discharge leads to the accumulation of heavy metals such as Cu, Zn, Ni, and Cr in the river and lake sediment. Once these heavy metals enter the water, they can accumulate in the surface sediment through adsorption, complexation, and precipitation. Their concentration in the sediment can exceed that in the overlying water by several orders of magnitude, becoming a reservoir and final destination for heavy metals in the water. Unlike organic matter, heavy metals cannot be degraded by microorganisms and can accumulate in organisms, thus posing a significant potential hazard to heavy metal pollutants.

[0003] Heavy metals in sediment possess irreversible and long-term characteristics. When environmental conditions change, some heavy metals may be released from the sediment through desorption, dissolution, and redox reactions, increasing the heavy metal concentration in the water solution and causing secondary water pollution. The continuous accumulation of heavy metals in sediment not only poses a serious threat to aquatic organisms, drinking water for riverside residents, and safe irrigation for farmland, but may also harm human health through the food chain. Therefore, the treatment of heavy metal-contaminated sediment (leaching or on-site solidification of heavy metal pollutants) is particularly necessary.

[0004] Currently, the main methods for treating polluted river and lake sediments include precipitation, oxidation-reduction, ion exchange, adsorption, and electrokinetic remediation. Among these, precipitation, oxidation-reduction, ion exchange, and adsorption methods suffer from drawbacks such as large reagent usage, slow reaction times, and unsatisfactory treatment effects. Electrokinetic remediation technology, by inserting electrodes into the polluted river and lake sediments and applying direct current, causes pollutants in the sediments to move directionally under the influence of the applied DC electric field and accumulate near the electrodes. Periodically removing the electrodes removes the pollutants, making it a highly efficient method for removing pollutants from sediments. However, existing electrokinetic remediation technologies lack the ability to visualize the pollutant migration process, making it difficult to accurately evaluate the treatment effect. Furthermore, current electrokinetic remediation methods for heavy metal pollutants in sediments only address the precipitation of heavy metals, lacking the concept of combined treatment and on-site disposal (on-site treatment and on-site solidification of heavy metal pollutants at the point of precipitation). Summary of the Invention

[0005] The present invention aims to provide an apparatus for heavy metal precipitation and solidification tests in river and lake sediments. It achieves the precipitation and solidification of heavy metals in sediments through electroosmosis combined with pre-compression and heavy metal chelating agents, as well as continuous drainage of sediments, thereby shortening the precipitation and adsorption cycle of heavy metal pollutants and the solidification cycle of sediments, and realizing the efficient precipitation and solidification of heavy metal pollutants in river and lake sediments.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The basic technical solution provided by this invention is: an apparatus for testing the precipitation and solidification of heavy metals in river and lake sediments, comprising a test tank, a power supply, a pressure plate, a return water tank, and several EKG drainage plates. The test tank is made of transparent material and is used to hold river and lake sediments. The pressure plate and the return water tank are both configured to cooperate with the test tank for compacting the river and lake sediments inside. The return water tank is located above the pressure plate. Both the pressure plate and the return water tank have several EKG plate slots, and the EKG drainage plates pass through these slots. Each of the EKG drainage plates includes a cathode and an anode. The EKG drainage plates are connected in parallel to the power supply via electrical wires. The base plate of the EKG drainage plate is inserted... The test tank contains river and lake sediment. The top and bottom of the EKG drainage board are connected to a liquid inlet. The test tank is connected to an outlet pump, a storage tank, and an inlet pump. The outlet pump and the inlet pump are electrically connected to a power source. The outlet pump's inlet is connected to an outlet pipe, the free end of which is located inside the test tank. The outlet pump's outlet is located on the upper side of the return water tank. The storage tank contains a heavy metal chelating agent and is connected to a guide pipe. The guide pipe is connected to the EKG drainage board through the inlet. The inlet end of the inlet pump is connected to the storage tank, and the outlet end of the inlet pump is connected to an inlet pipe, the free end of which is located inside the test tank.

[0008] The principle and beneficial effects of the basic technical solution: The test tank, made of transparent material, is used to hold the river and lake sediment to be treated, allowing observation of the changes in the sediment inside, which is beneficial for those skilled in the art to analyze it. The base plate of the EKG drainage board is inserted into the river and lake sediment after passing through the pressure plate and the EKG plate slots in the return water tank. When the power is turned on, the heavy metal pollution in the river and lake sediment is electrolytically separated. At the same time, the storage tank contains heavy metal chelating agents. Under the action of the inlet holes and inlet pipes of the EKG drainage board, the heavy metal ions separated by electrolysis in the river and lake sediment are chelated with it. The chelates are adsorbed on the EKG drainage board, completing the on-site treatment of the precipitation and solidification of heavy metal pollutants. Under the action of the pressure plate and the return water pump, the leachate in the river and lake sediment in the test tank flows back to the return water tank through the return water pipe. As the amount of return water increases, the overall weight of the return water tank increases, further improving the compaction effect on the river and lake sediment, and further accelerating the return water rate, thus forming a positive feedback. To achieve the precipitation, solidification, and combined treatment of heavy metal pollutants in river and lake sediments within the test tank.

[0009] Preferably, a filter screen is detachably connected to the inner side of the test tank, the river and lake bottom sediment contained in the test tank is located on the upper side of the filter screen, the free end of the water outlet pipe is located on the lower side of the filter screen, and the free end of the liquid inlet pipe is located on the upper side of the filter screen.

[0010] With the above setup, the filter screen separates the river and lake bottom sediment from the return water; the free end of the inlet pipe is located on the upper side of the filter screen to facilitate the chelation of heavy metal chelates with heavy metal ions; the free end of the outlet pipe is located on the lower side of the filter screen to prevent the bottom sediment from flowing back into the return water tank along with the return water.

[0011] Preferably, the inner side of the test tank is also provided with several geotextiles, which are intermittently placed between the river and lake bottom mud.

[0012] Preferably, the test tank is made of transparent tempered glass, and the heavy metal chelating agent contained in the storage tank is dithiocarbamate.

[0013] With the above setup, tempered glass exhibits stable physicochemical properties, making it suitable as a container for the electrolytic separation of river and lake sediments, and facilitating the observation of the sediment morphology on its inner surface by technicians; dithiocarbamates are effective against heavy metal ions Cu. 2+ Cd 2+ Hg 2 + Pb 2+ Mn 2+ Ni 2+ Zn 2+ Cr 3+ It has a good chelation effect.

[0014] Preferably, the EKG drainage board is in the form of multiple combined "I"-shaped grooves.

[0015] The above settings can effectively increase the contact area between the EKG drainage board and the river and lake sediment, which is beneficial to the electrolytic separation of the river and lake sediment, as well as the adsorption of heavy metal ions after chelation.

[0016] Preferably, the side wall of the EKG drainage plate is provided with a side hole, and the side hole, the liquid inlet, the free end of the water outlet pipe and the free end of the liquid inlet pipe are all connected to a liquid monopermeable membrane.

[0017] Through the above-described design, the side holes on the sidewall of the EKG drainage plate facilitate the chelation effect between electrolyzed heavy metal ions and the heavy metal chelating agent. The liquid single-permeation membrane ensures unidirectional liquid flow, guaranteeing the overall performance of the device. Specifically, the heavy metal chelating agent permeating from the sidewall located on the upper side of the return water tank flows into the return water tank and chelates with the heavy metal ions contained in the return water, further improving the treatment effect on heavy metal pollutants.

[0018] Preferably, the density of the side holes on the sidewall of the EKG drainage board increases sequentially from top to bottom.

[0019] Through the above setup, as the river and lake bottom sediment is continuously compacted, its density gradually increases from top to bottom, ensuring sufficient chelation between heavy metal chelating agent and electrolytic heavy metal ions. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the device used in the present invention for heavy metal precipitation and solidification tests in river and lake sediments;

[0021] Figure 2 This is a top view of the return water tank of the apparatus for heavy metal precipitation and solidification tests in river and lake sediments according to the present invention.

[0022] Figure 3 This is a schematic diagram of the EKG drainage board, the device for heavy metal precipitation and solidification tests in river and lake sediments according to the present invention.

[0023] The names of the corresponding labels in the attached diagram are:

[0024] Test tank 1, power supply 2, water pump 3, liquid storage tank 4, liquid inlet pump 5, water outlet pipe 6, liquid inlet pipe 7, filter screen 8, EKG drainage board 9, geotextile 10, pressure plate 11, return water tank 12, liquid guide pipe 13, EKG plate slot 14, cathode 15, anode 16, liquid inlet 17. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments:

[0026] like Figures 1 to 3 As shown, the apparatus for testing the precipitation and solidification of heavy metals in river and lake sediment includes a test tank 1, a power supply 2, a pressure plate 11, a return water tank 12, and several EKG drainage boards 9. The test tank 1 is made of transparent tempered glass and is used to hold river and lake sediment. A filter screen 8 is detachably attached to the inner side of the test tank 1, with the river and lake sediment placed on top of the filter screen 8. Several geotextiles 10 are also provided on the inner side of the test tank 1, intermittently placed between the river and lake sediment. The pressure plate 11... Both the return water tank 12 and the test tank 1 are configured to compact the river and lake bottom sediment inside the test tank 1. The return water tank 12 is located on the upper side of the pressure plate 11. The EKG drainage plate 9 is in the form of multiple combined "I"-shaped grooves. Both the pressure plate 11 and the return water tank 12 have several EKG plate hole slots 14 that cooperate with the EKG drainage plate 9. The EKG drainage plate 9 passes through the EKG plate hole slots 14. Each of the EKG drainage plates 9 includes a cathode 15 and an anode 16. The EKG drainage plates 9 are connected to each other. The power supply is connected to the power source 2 after the parallel connection of the conductors. The base plate of the EKG drainage board 9 is inserted into the river and lake bottom sediment contained in the test tank 1. The top and bottom of the EKG drainage board 9 are connected by a liquid inlet 17, and the side wall has side holes with increasing density from top to bottom. The test tank 1 is connected to a water outlet pump 3, a liquid storage tank 4, and a liquid inlet pump 5. The water outlet pump 3 and the liquid inlet pump 5 are electrically connected to the power source 2. The water outlet pump 3 is connected to a water outlet pipe 6 at its inlet. The free end of the water outlet pipe 6 is located below the filter screen 8. The outlet of 3 is located on the upper side of the return water tank 12; the storage tank 4 contains heavy metal chelating agent dithiocarbamate, the storage tank 4 is connected to the liquid guide pipe 13, the liquid guide pipe 13 is connected to the EKG drainage plate 9 through the liquid inlet 17, the inlet end of the liquid pump 5 is connected to the storage tank 4, the outlet end of the liquid pump 5 is connected to the liquid inlet pipe 7, the free end of the liquid inlet pipe 7 is located on the upper side of the filter screen 8; the side hole, the liquid inlet 17, the free end of the outlet pipe 6 and the free end of the liquid inlet pipe 7 are all connected to a liquid monoosmotic membrane.

[0027] The specific implementation process is as follows:

[0028] Before using this device, fill the storage tank 4 with a sufficient amount of heavy metal chelating agent dithiocarbamate. Remove the filter screen 8, geotextile 10, EKG drainage board 9, pressure plate 11, and return water tank 12 from the test tank 1. When using this device, first connect the inlet pipe 7 and outlet pipe 6 to the inlet pump 5 and outlet pump 3 respectively. Then, attach the filter screen clip 8 to the inside of the test tank 1, with the free end of the inlet pipe 7 passing through the filter screen 8 and positioned above it. Then, fill the test tank 1 with river and lake bottom sediment in sequence. During the process of filling the river and lake bottom sediment, several geotextiles 10 are placed intermittently. After the river and lake bottom sediment is filled, a pressure plate 11 and a return water tank 12 are placed on its upper side in sequence. Then, EKG drainage boards 9 are passed through the EKG plate holes 14 of the pressure plate 11 and the return water tank 12 in sequence. Several EKG drainage boards 9 are connected in parallel with electrical wires and then connected to the power supply 2. Several EKG drainage boards 9 are connected by a liquid guide pipe 13, thus completing the test preparation of this device. When using it, simply turn on the power supply 2.

[0029] The test tank 1, made of transparent tempered glass, is used to hold the river and lake sediment to be treated, facilitating the observation of the sediment morphology on its inner side by technicians. After ionization, the heavy metal pollutants in the river and lake sediment are chelated with a heavy metal chelating agent, and the final chelate is adsorbed on the EKG drainage board 9, completing the on-site treatment of the precipitation and solidification of heavy metal pollutants. This achieves the precipitation, solidification, and combined treatment of heavy metal pollutants in the river and lake sediment in the test tank 1.

[0030] Filter screen 8 separates river and lake bottom sediment from return water; the free end of inlet pipe 7 is located on the upper side of filter screen 8 to facilitate the chelation of heavy metal chelates with heavy metal ions; the free end of outlet pipe 6 is located on the lower side of filter screen 8 to prevent bottom sediment from flowing back into return water tank 12 along with the return water; the heavy metal chelating agent dithiocarbamate is effective against heavy metal ions Cu 2+ Cd 2+ Hg 2+ Pb 2+ Mn 2+ Ni 2+ Zn 2+ Cr 3+The EKG drainage plate 9, with its multiple combined "I"-shaped troughs, increases its contact area with river and lake sediment, facilitating electrolytic separation and adsorption after chelation. Side holes on the sidewalls of the EKG drainage plate 9 enhance the chelation effect between electrolyzed heavy metal ions and the heavy metal chelating agent. The liquid single-permeation membrane ensures unidirectional liquid flow, guaranteeing the overall performance of the device. The heavy metal chelating agent seeping from the sidewall of the return water tank 12 flows into the return water tank 12, chelating with the heavy metal ions in the return water, further improving the treatment effect on heavy metal pollutants. The sidewalls of the EKG drainage plate 9 have side holes with increasing density from top to bottom. As the river and lake sediment is continuously compacted, its density gradually increases from top to bottom, ensuring sufficient heavy metal chelating agent for chelation with electrolyzed heavy metal ions.

[0031] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific technical solutions or characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An apparatus for testing the precipitation and solidification of heavy metals in river and lake sediments, characterized in that: The system includes a test tank, a power supply, a pressure plate, a return water tank, and several EKG drainage boards. The test tank is made of transparent material and is used to hold river and lake sediment. The pressure plate and the return water tank are both configured to cooperate with the test tank for compacting the river and lake sediment inside. The return water tank is located above the pressure plate. Both the pressure plate and the return water tank have several EKG plate slots, and the EKG drainage boards pass through these slots. Each EKG drainage board includes a cathode and an anode. The EKG drainage boards are connected in parallel to the power supply via electrical wires. The base plate of each EKG drainage board is inserted into the river and lake sediment contained in the test tank. The EKG drainage plate has an inlet port at its top and bottom; the test tank is connected to an outlet pump, a storage tank, and an inlet pump, which are electrically connected to a power source; the outlet pump is connected to an outlet pipe, the free end of which is located inside the test tank, and the outlet of which is located on the upper side of the return water tank; the storage tank contains a heavy metal chelating agent, and is connected to a guide pipe, which is connected to the EKG drainage plate through the inlet port; the inlet end of the inlet pump is connected to the storage tank, and the outlet end of the inlet pump is connected to an inlet pipe, the free end of which is located inside the test tank; The side wall of the EKG drainage board has side holes, and the side holes, the liquid inlet, the free end of the water outlet pipe, and the free end of the liquid inlet pipe are all connected to a liquid monopermeable membrane; the density of the side holes on the side wall of the EKG drainage board increases sequentially from top to bottom.

2. The apparatus for heavy metal precipitation and solidification tests in river and lake sediments according to claim 1, characterized in that: A filter screen is detachably connected to the inner side of the test tank. The river and lake sediment contained in the test tank is located on the upper side of the filter screen. The free end of the water outlet pipe is located on the lower side of the filter screen, and the free end of the liquid inlet pipe is located on the upper side of the filter screen.

3. The apparatus for heavy metal precipitation and solidification tests in river and lake sediments according to claim 1, characterized in that: The inner side of the test tank is also provided with several geotextiles, which are intermittently placed between the river and lake bottom mud.

4. The apparatus for heavy metal precipitation and solidification tests in river and lake sediments according to claim 1, characterized in that: The test tank is made of transparent tempered glass, and the heavy metal chelating agent contained in the storage tank is dithiocarbamate.

5. The apparatus for heavy metal precipitation and solidification tests in river and lake sediments according to claim 1, characterized in that: The EKG drainage board is in the form of multiple combined "I" shaped grooves.

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