Hexavalent chromium reduction separation and synchronous monitoring device and use method

Abstract

The invention relates to the technical field of underground water monitoring and treatment, in particular to a hexavalent chromium reduction separation and synchronous monitoring device and a using method thereof.The device comprises a sleeve type electrode system and a control system, the sleeve type electrode system is electrically connected with the control system, and the sleeve type electrode system is used for adsorbing and reducing hexavalent chromium in underground water; the control system is used for monitoring whether hexavalent chromium exists in underground water or not; wherein the sleeve type electrode system comprises a reference electrode, a well casing, a cathode assembly, an isolation column and an anode assembly, the control system comprises an electrochemical work station, the electrochemical work station is connected with the cathode assembly, the reference electrode and the anode assembly, and the isolation column is located between the anode assembly and the cathode assembly. The isolation column has a porous structure and is filled with a conductive material. According to the application, the pollution concentration of hexavalent chromium in underground water can be found in time, the hexavalent chromium adsorption efficiency is improved, and a signal can be conveniently and quickly identified.

Description

Technical Field

[0001] This application relates to the technical field of groundwater monitoring and treatment, and particularly to a hexavalent chromium reduction and separation and synchronous monitoring device and its usage method. Background Art

[0002] Groundwater is one of the most important fresh water resources on earth and a precious resource on which humans depend for survival. In recent years, with the rapid development of society and the acceleration of the urbanization process in China, remarkable achievements have been made in the fields of industrial and agricultural production, transportation, etc. However, this process has also brought environmental pollution problems. In particular, the development of industries such as textile, chemical, steel, leather-making, and electroplating has led to the large generation of chromium slag, dust, and chromium-containing wastewater. These pollutants have caused the concentration of hexavalent chromium in groundwater to rise sharply, even reaching 100 mg / L or higher. Hexavalent chromium is not only easily soluble in water but also shows high mobility in soil and groundwater and is recognized by the international community as a carcinogenic metal compound.

[0003] Traditional heavy metal monitoring methods such as chromatography, spectroscopy, and mass spectrometry use instruments with large sizes and complex operations, which are not suitable for on-site real-time monitoring; electrochemical methods such as voltammetric stripping analysis and ion-selective electrode method require frequent calibration, high cost per unit, and low determination accuracy when multiple heavy metal ions coexist, and are not suitable for specific network monitoring of hexavalent chromium in large-area and long-span groundwater. Therefore, how to effectively treat hexavalent chromium pollution in groundwater has become a major challenge urgently to be solved in the field of environmental remediation. Summary of the Invention

[0004] In order to improve the adsorption efficiency of hexavalent chromium and reduce the economic cost, this application provides a hexavalent chromium reduction and separation and synchronous monitoring device and its usage method.

[0005] In a first aspect, this application provides a hexavalent chromium reduction and separation and synchronous monitoring device, adopting the following technical solution: A hexavalent chromium reduction and separation and synchronous monitoring device includes a sleeve-type electrode system and a control system. The sleeve-type electrode system is electrically connected to the control system. The sleeve-type electrode system is used for adsorbing and reducing hexavalent chromium in groundwater, and the control system is used for monitoring whether there is hexavalent chromium in groundwater; Among them, the sleeve-type electrode system includes a reference electrode, a well pipe, a cathode assembly, a separation column, and an anode assembly. The control system includes an electrochemical workstation. The electrochemical workstation is respectively connected to the cathode assembly, the reference electrode, and the anode assembly. The separation column is located between the anode assembly and the cathode assembly, and the separation column has a porous structure and is filled with a conductive material.

[0006] By adopting the above technical solution, a voltage is applied to the sleeve electrode system according to the control system, so that the sleeve electrode system reduces hexavalent chromium in groundwater and adsorbs it in the anode assembly. Through the monitoring of the control system, the pollution concentration of hexavalent chromium in groundwater can be detected in time, the adsorption efficiency of hexavalent chromium can be improved, and signals can be identified conveniently and quickly.

[0007] In some of the embodiments, the sleeve electrode system is 1 to 6 meters long, and the outer diameter of the sleeve electrode system is 100 to 300 millimeters.

[0008] In some of the embodiments, the anode assembly includes an anode adsorption material, and the anode adsorption material is a conductive material with adsorption ability.

[0009] By adopting the above technical solution, the adsorption material in the anode assembly has a large surface area, increasing the electron transfer area, thereby reducing the overpotential. That is, when an external voltage is applied, the positive potential of the anode can be effectively reduced, thereby maximizing the negative potential of the cathode. Therefore, this technology only needs to apply a lower external voltage to reach the potential required for the cathode to reduce hexavalent chromium, thereby reducing the operating energy consumption of the overall equipment.

[0010] In some of the embodiments, the cathode assembly includes a cathode material, and the cathode material is based on a metal material or stainless steel.

[0011] In a second aspect, the present application provides a method for using a hexavalent chromium reduction separation and synchronous monitoring device, adopting the following technical solution: A method for using a hexavalent chromium reduction separation and synchronous monitoring device, based on the hexavalent chromium reduction separation and synchronous monitoring device described in the first aspect, includes the following steps: Obtain the polluted area, and analyze it according to the regional location and pollutant distribution corresponding to the polluted area to generate a repair well setting area; Lay out repair wells in the repair well setting area. The repair wells are provided with corresponding hexavalent chromium reduction separation and synchronous monitoring devices, and the electrode system includes a cathode assembly and an anode assembly; Form a supported cathode biofilm according to the cathode material of the cathode assembly, and pass the cathode biofilm and the anode assembly into a preset potential based on the control system to reduce and adsorb the hexavalent chromium content in groundwater.

[0012] By adopting the above technical solution, analyze according to the regional location corresponding to the polluted area and the pollutant distribution to generate the area for setting up the remediation wells. Set up the remediation wells in the area for setting up the remediation wells. The layout density of the remediation wells is related to the pollution degree of the plot, and can perform corresponding treatment according to the groundwater pollution situation, improving the sewage discharge efficiency of the groundwater; form a supported cathode biofilm based on the cathode material of the cathode assembly. The cathode biofilm formed in the cathode assembly is used to identify the entry of hexavalent chromium detected and can judge the range of hexavalent chromium concentration according to the open circuit potential response. When the anode assembly adsorbs a certain concentration of hexavalent chromium, the anode assembly should be replaced in time to improve the hexavalent chromium adsorption efficiency and can conveniently and quickly identify the signal.

[0013] In some of these embodiments, forming the supported cathode biofilm based on the cathode material of the cathode assembly includes the following steps: Use the electrode material in the cathode assembly as the anode, apply a first preset electric potential and operate for a first preset time to obtain an anode biofilm; Apply a second preset electric potential to the anode biofilm, perform bioanode reversal and operate for a second preset time to obtain a cathode biofilm.

[0014] By adopting the above technical solution, in-situ reverse cultivation of the cathode biofilm can improve the energy utilization efficiency, promote the formation of the biofilm, improve the stability of the biofilm, and reduce hexavalent chromium in the groundwater based on the cathode biofilm to obtain trivalent chromium, facilitating the adsorption of trivalent chromium by the anode assembly, and further improving the reduction and adsorption efficiency of hexavalent chromium in the groundwater.

[0015] In some of these embodiments, the cathode assembly includes a cathode material. Before forming the supported cathode biofilm based on the cathode material of the cathode assembly, the following steps are further included: Place the cathode material in acetone, ethanol, and deionized water for ultrasonic cleaning treatment for a third preset time to obtain a preliminarily cleaned material; Place the preliminarily cleaned material in a tubular furnace and treat it in a first preset reduction atmosphere to obtain a first reduced material; Treat the first reduced material in a second preset reduction atmosphere to obtain a second reduced material; Cool the second reduced material to room temperature in pure helium to achieve surface carbon coating modification of the cathode material; Wherein, in the first preset reduction atmosphere, the ratio of hydrogen to helium is 3:1.

[0016] By adopting the above technical solution, surface carbon coating modification of the cathode material can be used as a buffer layer to reduce the iron catalytic effect and avoid the formation of amorphous carbon.

[0017] In some of these embodiments, the first reduction material is processed in a second preset reduction atmosphere to obtain a second reduction material, wherein the generation method of the second reduction material includes the following steps; Place the first reduction material in a mixed gas of hydrogen, helium, and methane, with the growth temperature being a first preset temperature, and grow the first reduction material in the second preset reduction atmosphere for a fourth preset time; Among them, the ratio of hydrogen, helium, and methane in the second preset reduction atmosphere is 1:4:1.

[0018] In some of these embodiments, the control system includes an electronic monitoring display. After the control system powers on the sleeve electrode system, the following steps are included: Regularly obtain the absolute open-circuit value and determine whether the absolute open-circuit value is lower than a preset value; If the absolute open-circuit value is lower than the preset value, generate a toxicity pollution signal and obtain the adsorption quantity based on the toxicity pollution signal; Compare the adsorption quantity with a preset quantity and determine whether the adsorption data exceeds the preset quantity; If the adsorption quantity exceeds the preset quantity, generate a packing replacement signal and send the packing replacement signal to the electronic monitoring display.

[0019] By adopting the above technical solution, regularly obtain the absolute open-circuit value and compare the absolute open-circuit value with a preset value. If the absolute open-circuit value is lower than the preset value, generate a toxicity pollution signal, which can timely monitor whether there is a toxicity pollution of hexavalent chromium in groundwater. When it is determined that there is a toxicity pollution of hexavalent chromium in groundwater, obtain the adsorption quantity based on the toxicity pollution signal; compare the adsorption quantity with a preset quantity and determine whether the adsorption data exceeds the preset quantity; if the adsorption quantity exceeds the preset quantity, generate a packing replacement signal and send the packing replacement signal to the electronic monitoring display, so that the staff can replace the anode assembly without reinstalling the device, reducing the economic cost.

[0020] In some of these embodiments, when determining whether the absolute open-circuit value is lower than a preset value, the preset value is 20% - 50% of the absolute potential value. Among them, the acquisition method of the absolute potential value includes the following steps: Power on the sleeve electrode system in a preset power-on mode, obtain the open-circuit potential signal generated by the biocathode, and obtain the absolute potential value based on the open-circuit potential signal.

[0021] In summary, the present application includes at least one of the following beneficial technical effects: 1. Apply voltage to the sleeve electrode system according to the control system, so that the sleeve electrode system reduces hexavalent chromium in groundwater and adsorbs it in the anode assembly. Through the monitoring of the control system, the pollution quantity of hexavalent chromium in groundwater can be detected in time, so that the anode assembly can be replaced in time, the adsorption efficiency of hexavalent chromium can be improved, and the economic cost can be reduced; 2. Monitor the hexavalent chromium concentration by open circuit potential because the open circuit potential provides a method for real-time monitoring of the change of pollutant concentration. When the pollutant concentration changes, the open circuit potential can respond quickly, and the change of the open circuit potential can reflect the active state of the cathode biofilm, so as to evaluate the toxic effect of pollutants on the biofilm; 3. When the hexavalent chromium adsorption value reaches the preset quantity, the anode adsorption substance needs to be replaced in time. If the adsorbent is used for a long time, its structure or active sites will change, resulting in a decrease in adsorption, and the pollutants will enter the water body again, reducing the treatment efficiency. Frequent replacement can ensure the adsorption efficiency, but at the same time, it will also increase the treatment cost and operation complexity. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the hexavalent chromium reduction, separation and synchronous monitoring device provided by the embodiment of the present application; Figure 2 It is a step block diagram of the device usage method provided by the embodiment of the present application; Figure 3 It is a schematic structural diagram of the electronic device provided by the embodiment of the present application; Figure 4 It is a step block diagram of the monitoring method provided by the embodiment of the present application.

[0023] Description of the reference numerals: 10, electronic monitoring display; 20, electrochemical workstation; 31, reference electrode; 32, well pipe; 33, cathode assembly; 34, isolation column; 35, anode assembly; 40, microorganism; 51, processor; 52, memory; 53, computer program. Detailed Embodiments

[0024] To better understand the purpose, technical solution, and advantages of this application, the following describes and explains this application in conjunction with the accompanying drawings and embodiments. However, those of ordinary skill in the art should understand that this application can be implemented without these details. In some cases, to avoid unnecessary descriptions from obscuring aspects of this application, well-known methods, processes, systems, components, and / or circuits that have been described at a higher level will not be elaborated further. For those of ordinary skill in the art, it is obvious that various changes can be made to the disclosed embodiments of this application, and without departing from the principles and scope of this application, the general principles defined in this application can be applied to other embodiments and application scenarios. Therefore, this application is not limited to the illustrated embodiments, but rather conforms to the broadest scope consistent with the scope claimed in this application.

[0025] An embodiment of this application discloses a hexavalent chromium reduction, separation, and synchronous monitoring device.

[0026] As Figure 1 shown, a hexavalent chromium reduction, separation, and synchronous monitoring device includes a sleeve-type electrode system and a control system. The sleeve-type electrode system is electrically connected to the control system. The sleeve-type electrode system is used to adsorb and reduce hexavalent chromium in groundwater, and the control system is used to monitor whether there is hexavalent chromium in groundwater.

[0027] Among them, the sleeve-type electrode system includes a reference electrode 31, a well pipe 32, a cathode assembly 33, an isolation column 34, and an anode assembly 35. The control system includes an electronic monitoring display 10 and an electrochemical workstation 20. The electronic monitoring display 10 is electrically connected to the electrochemical workstation 20, and the electrochemical workstation 20 has three connection holes, which are respectively connected to the electrode materials in the reference electrode 31, the anode assembly 35, and the cathode assembly 33.

[0028] Specifically, since the hexavalent chromium pollution in groundwater is generally in the range of 3 to 5 meters, the sleeve-type electrode system is designed to be 1 to 6 meters long. Since too small an aperture will lead to a reduction in the reduction and adsorption function, and too large an aperture will lead to too high a construction cost, the outer aperture of the sleeve-type electrode system in this embodiment is set to 100 to 300 millimeters.

[0029] The main function of the reference electrode 31 is to provide a stable potential reference. The well pipe 32 is made of a PVC material, a PE material, or one or more of them, with toughness and corrosion resistance. The well pipe 32 is filled with one or more of sand, quartz, and cement, and has a supporting effect.

[0030] The cathode assembly 33 includes a cathode material, which is based on a metal material or stainless steel. Since the metal material has good electrical conductivity and surface attachment effect on microorganisms 40, and the stainless steel material has good corrosion resistance, the surface modification of the cathode material using conductive polymers, nanomaterials, and electrochemical corrosion can improve its microorganism 40 loading capacity.

[0031] The isolation column 34 is located between the anode assembly 35 and the cathode assembly 33. The isolation column 34 has a uniformly distributed porous structure and has a water permeation function. The isolation column 34 has a porous structure and is filled with a conductive material, which separates the anode assembly 35 and the cathode assembly 33 to form an anodic reaction chamber and a cathodic reaction chamber. The anode assembly is located in the anodic reaction chamber, and the cathode assembly is located in the cathodic reaction chamber. The conductive material includes one or more of metal powder, carbon black filler, and chitosan, but is not limited thereto.

[0032] The anode assembly 35 includes an anode adsorption material, and the anode adsorption material is a conductive material with adsorption ability. The anode material is selected from one or more of metal-organic framework materials, activated carbon, and adsorption polymers. Since the metal-organic framework material has a high specific surface area, rich active sites, and is easy to be chemically modified, the activated carbon has the characteristics of corrosion resistance, high specific surface area, and low cost, and the adsorption polymer has a high porosity and rich functional groups, which can provide various interaction forces during the adsorption process.

[0033] In addition, the action range radius of the sleeve-type electrode system for contaminated sites is 1 to 2 meters, and the spacing between them is 2 to 4 meters. Although a too small spacing can improve the accuracy of data, it may lead to an increase in monitoring costs. A too large spacing may not accurately reflect the distribution of pollutants and may cause the pollution source not to be covered within the monitoring range, making it impossible to detect and handle pollution problems in a timely manner.

[0034] In another embodiment, the present application also discloses a method for using a hexavalent chromium reduction separation and synchronous monitoring device.

[0035] Refer to Figure 2 , the method for using a hexavalent chromium reduction separation and synchronous monitoring device, based on the hexavalent chromium reduction separation and synchronous monitoring device provided in the above embodiment, includes the following steps: S100, obtain the contaminated area, and analyze it according to the corresponding regional location and pollutant distribution of the contaminated area to generate a repair well setting area.

[0036] S200, arrange repair wells in the repair well setting area, and the corresponding hexavalent chromium reduction separation and synchronous monitoring device is provided in the repair wells.

[0037] In S300, a cathode biofilm is formed based on the cathode material of the cathode assembly. The cathode biofilm and the anode assembly are introduced into a preset electric potential based on a control system to reduce and adsorb the hexavalent chromium content in groundwater.

[0038] Among them, the polluted area represents the area polluted by hexavalent chromium, the area where the remediation well is set represents the area where the remediation well is set. The electrochemical workstation 20 in the control system energizes the electrode material in the cathode assembly 33 to generate a cathode biofilm in the remediation well, facilitating the subsequent reduction of hexavalent chromium in groundwater. Then, the reduced hexavalent chromium is adsorbed by the anode assembly 35 to complete the reduction and adsorption of hexavalent chromium in groundwater. The preset electric potential mentioned here is an electric potential of -0.8 to -0.4V, which is set based on the reference electrode 31. The electrode system includes a cathode assembly and an anode assembly. The control system further includes an electronic device. The electronic device includes a memory 52 and a processor 51 that are coupled to each other. A computer program 53 capable of running on the processor 51 is stored on the memory 52. When the computer program 53 is executed by the processor 51, it realizes the usage method of the hexavalent chromium reduction and separation and synchronous monitoring device.

[0039] Refer to Figure 1 and Figure 3 , the processor 51 can be a central processing unit 51, a general-purpose processor 51, a digital signal processor 51, an application specific integrated circuit, a field programmable gate array or other programmable logic devices, transistor logic devices, hardware components or any combination thereof. It is used to run the program code stored in the memory 52 or process data.

[0040] The memory 52 can be a ROM or other types of static storage devices that can store static information and instructions, a random access memory 52, or other types of dynamic storage devices that can store information and instructions. It can also be an electrically erasable programmable read-only memory 52, a compact disc read-only memory or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer, but is not limited thereto. The memory 52 can be an internal storage unit in some embodiments.

[0041] The processor 51 and the memory 52 are connected by a bus. The bus can include a path for transmitting information between the above components. The bus can be a peripheral component interconnect standard bus or an extended industry standard architecture bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. For the sake of representation, Figure 3 only a thick line is shown in

[0042] Specifically, the processor 51 evenly arranges the remediation wells according to the plot location and shape of the polluted area and the distribution of pollutants in the plot. A sleeve-type electrode system is arranged in the remediation wells, and microbial 40 bacterial liquid is added to the cathode reaction chamber. The electricity-producing microorganisms 40 include, but are not limited to, one or more of the genus Geobacter, the genus Shewanella, and the genus Pseudomonas. Then, based on the cathode assembly 33 and the control system, a cathode biofilm is generated, and the cathode biofilm and the anode assembly 35 are energized with a preset electric potential based on the control system to reduce the hexavalent chromium content adsorbed in the groundwater.

[0043] It should be noted here that arranging the remediation wells includes, but is not limited to, the plum blossom-shaped point layout method or the checkerboard-shaped point layout method. These methods are representative and have uniform distribution to ensure the accuracy and reliability of the monitoring data. The specific point layout should be determined according to the specific location distribution of the polluted site.

[0044] In addition, the electricity-producing microorganisms 40 of the genus Geobacter, the genus Shewanella, and the genus Pseudomonas have efficient electron transfer capabilities, can convert chemical energy into electrical energy, and can adapt to different environmental conditions, such as different temperatures, electric fields, pressures, salinities, and pH values.

[0045] In another embodiment, forming a supported cathode biofilm based on the cathode material of the cathode assembly includes the following steps: Using the electrode material in the cathode assembly 33 as the anode, applying a first preset electric potential and operating for a first preset time to obtain an anode biofilm.

[0046] Applying a second preset electric potential to the anode biofilm, performing a bioanode reversal and operating for a second preset time to obtain a cathode biofilm.

[0047] Among them, the first preset electric potential includes an electric potential of -0.2 to 0.2 V, the first preset time includes 3 to 7 days, the second preset electric potential includes an electric potential of -0.8 to -0.4 V, and the second preset time includes 2 to 3 days. The first preset electric potential and the second preset electric potential mentioned here are both based on the reference electrode 31.

[0048] Specifically, after adding one or more of the microorganisms 40 of the genus Geobacter, the genus Shewanella, and the genus Pseudomonas to the cathode assembly 33, an electric potential of -0.2 to 0.2 V is applied, and it is stably operated for 3 to 7 days to cultivate the anode biofilm.

[0049] In the cathode assembly 33, the cathode is reversely cultured in situ to cultivate the cathode biofilm. The applied electric potential is adjusted to -0.8 to -0.4 V, a bioanode reversal is performed, the cathode biofilm is cultivated, and it is stably operated for 2 to 3 days until the current is stable, and it is considered that the cultivation of the cathode biofilm is completed.

[0050] It should be noted here that in-situ reverse cultivation of the cathode biofilm can improve energy utilization efficiency, promote biofilm formation, and enhance the stability of the biofilm. In-situ reverse in the cathode assembly 33 refers to the abnormal reversal of the function or polarity of the cathode during operation, resulting in its transformation from an electron acceptor to an electron donor, or a phenomenon where the potential behavior is contrary to the design. The specific reverse process is prior art and will not be elaborated here. Bioanode reversal generally refers to the abnormal shift of the electrode potential of the anode in a microbial fuel cell or a similar bioelectrochemical system, resulting in a phenomenon where its potential is higher than that of the cathode. The specific operation is a routine operation and will not be elaborated here.

[0051] In another embodiment, the cathode assembly 33 includes a cathode material. Before forming the supported cathode biofilm based on the cathode material of the cathode assembly, the following steps are further included: Place the cathode material in acetone, ethanol, and deionized water for ultrasonic cleaning treatment for a third preset time to obtain a preliminarily cleaned material.

[0052] Place the preliminarily cleaned material in a tube furnace and treat it in a first preset reduction atmosphere to obtain a first reduced material.

[0053] Treat the first reduced material in a second preset reduction atmosphere to obtain a second reduced material.

[0054] Cool the second reduced material in pure helium to room temperature to achieve surface carbon coating modification of the cathode material.

[0055] Among them, the third preset time includes 30 minutes. The first reduced material is the material generated after being treated in the first preset reduction atmosphere. The specific acquisition method includes the following steps: Place the preliminarily cleaned material in a tube furnace. Under a reducing atmosphere with a hydrogen-to-helium ratio of 3:1, heat it from room temperature to 850 °C in 50 minutes and keep it at this temperature for 10 minutes to ensure that the surface of the generated first reduced material electrode is in a reduced state.

[0056] Then, treat the first reduced material in a second preset reduction atmosphere to obtain a second reduced material. Among them, the generation method of the second reduced material includes the following steps.

[0057] Place the first reduced material in a mixed gas of hydrogen, helium, and methane, and the growth temperature is the first preset temperature. Keep the first reduced material in the second preset reduction atmosphere for growth for a fourth preset time. The first preset temperature is 850 °C, and the fourth preset time is 30 minutes.

[0058] Specifically, the mixed gas in the first preset reduction atmosphere is modified to a growth atmosphere with a hydrogen, helium, and methane ratio of 1:4:1, and grown at 850 °C for 30 minutes. Finally, the cathode material electrode is cooled to room temperature in pure helium, that is, the carbon coating modification on the surface of the cathode material electrode is completed.

[0059] Refer to Figure 1 and Figure 4 , in another embodiment, after the cathode biofilm and the anode assembly 35 are applied with a preset electric potential based on the control system, the following steps are included: S400, regularly obtain the absolute value of the open circuit, and determine whether the absolute value of the open circuit is lower than a preset value.

[0060] S500, if the absolute value of the open circuit is lower than the preset value, generate a toxicity pollution signal, and obtain the adsorption quantity based on the toxicity pollution signal.

[0061] S600, compare the adsorption quantity with the preset quantity, and determine whether the adsorption quantity exceeds the preset quantity.

[0062] S700, if the adsorption quantity exceeds the preset quantity, generate a packing replacement signal, and send the packing replacement signal to the electronic monitoring display.

[0063] Among them, the absolute value of the open circuit represents the open circuit potential formed in the bioanode and the biocathode. The preset value is 20% - 50% of the absolute value of the potential. The method for obtaining the absolute value of the potential includes the following steps: Apply electricity to the sleeve electrode system in a preset power-on mode, obtain the open circuit potential signal generated by the biocathode, and obtain the absolute value of the potential based on the open circuit potential signal.

[0064] Specifically, the open circuit potential of the biocathode is about -220 mV. Take the absolute value of the open circuit potential of the biocathode as the absolute value of the potential. Subsequently, when monitoring the potential change of the biocathode, when the absolute value of the open circuit changes by 20% - 50%, that is, when the absolute value of the open circuit changes by 44 mV - 110 mV, it is determined that the groundwater has been contaminated by hexavalent chromium, that is, a toxicity pollution signal is generated.

[0065] Exemplarily, the 20% - 50% open circuit potential response corresponds to 60 - 300 mg / L of hexavalent chromium in the water body. When the open circuit potential is higher than 50%, it indicates that the hexavalent chromium in the groundwater is greater than 300 mg / L. When the open circuit potential is lower than 20%, it indicates that the concentration is too low or the monitoring is inaccurate.

[0066] The toxicity pollution signal indicates that the current hexavalent chromium reduction and separation and synchronous monitoring device has detected a pollution signal of hexavalent chromium in groundwater. When the pollution signal is detected, the content of hexavalent chromium in the current groundwater body is calculated through the toxicity pollution signal, the adsorption quantity is obtained through calculation, and the adsorption quantity is compared with the preset quantity to determine whether the adsorption data exceeds the preset quantity. If the adsorption quantity exceeds the preset quantity, a filler replacement signal is generated and sent to the electronic monitoring display 10 for the staff to replace. The adsorption quantity here is displayed through the electronic monitoring display 10.

[0067] It should be noted here that the preset quantity includes 20 - 50 mg / g, specifically meaning that 1 g of adsorption filler can absorb 20 - 50 mg of hexavalent chromium. Specifically, by applying a potential of -0.8~-0.4 V, the concentration of hexavalent chromium in groundwater is monitored by the electrochemical workstation 20. Open-circuit potential monitoring is carried out for 5 - 10 minutes every 30 - 60 minutes, and the absolute value of its open-circuit potential is monitored and recorded. When the absolute value of the open-circuit potential is significantly lower than 20% - 50% times its average value, the toxicity pollution of hexavalent chromium is detected. Through the adsorption effect of the bioanode, the surrounding hexavalent chromium is adsorbed. When flowing through the biocathode, it is reduced to trivalent chromium and then further adsorbed onto the anode surface. When the hexavalent chromium adsorption value of the anode adsorption filler reaches 20 - 50 mg / g, the anode adsorption substance needs to be replaced in time and desorbed. For example Figure 1 F1 in it represents the anode adsorption filler with a hexavalent chromium adsorption value reaching 20 - 50 mg / g, while F2 represents the replaced anode adsorption substance.

[0068] The implementation principle is as follows: First, according to the location shape of the polluted area and the distribution of pollutants in the plot, remediation wells are evenly arranged. A sleeve-type electrode system is arranged in the remediation wells. After adding one or more of the microbial strains Geobacter, Shewanella, and Pseudomonas in the cathode assembly 33, a potential of -0.2~0.2 V is applied and stably operated for 3 - 7 days to cultivate the anode biofilm. The cathode biofilm is cultivated in situ by reversing the cathode in the cathode assembly 33. The applied potential is adjusted to -0.8~-0.4 V for bioanode reversal to cultivate the cathode biofilm, and it is stably operated for 2 - 3 days until the current is stable, indicating that the cultivation of the cathode biofilm is completed.

[0069] Next, by applying a potential of -0.8 to -0.4 V, the concentration of hexavalent chromium in groundwater is monitored through the electrochemical workstation 20. Open-circuit potential monitoring is carried out for 5 to 10 minutes every 30 to 60 minutes, and the absolute value of the open-circuit potential is monitored and recorded. When the absolute value of the open-circuit potential is significantly lower than 20% to 50% times its average value, the toxic pollution of hexavalent chromium is detected. Through the adsorption of the bioanode, the surrounding hexavalent chromium is adsorbed. When it flows through the biocathode, it is reduced to trivalent chromium and then further adsorbed onto the anode surface.

[0070] Finally, when the adsorption value of hexavalent chromium reaches 20 to 50 mg / g of the anode adsorption filler, the anode adsorption substance needs to be replaced in time and desorbed.

[0071] It should be understood that although the steps in the flowchart of the accompanying drawings are shown in sequence according to the indication of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit and can be executed in other orders.

[0072] The above are all the preferred embodiments of this application, and the protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. A hexavalent chromium reduction separation and synchronous monitoring device, characterized in that, It includes a sleeve - type electrode system and a control system. The sleeve - type electrode system is electrically connected to the control system. The sleeve - type electrode system is used to adsorb and reduce hexavalent chromium in groundwater, and the control system is used to monitor whether there is hexavalent chromium in groundwater. Among them, the sleeve - type electrode system includes a reference electrode (31), a well pipe (32), a cathode assembly (33), a spacer column (34), and an anode assembly (35). The control system includes an electrochemical workstation (20). The electrochemical workstation (20) is respectively connected to the cathode assembly (33), the reference electrode (31), and the anode assembly (35). The spacer column (34) is located between the anode assembly (35) and the cathode assembly (33), and the spacer column (34) has a porous structure and is filled with a conductive material.

2. The hexavalent chromium reduction, separation and synchronous monitoring device according to claim 1, characterized in that The sleeve - type electrode system is 1 - 6 meters long, and the outer diameter of the sleeve - type electrode system is 100 - 300 millimeters.

3. The hexavalent chromium reduction, separation and synchronous monitoring device according to claim 1, characterized in that, The anode assembly (35) includes an anode adsorption material, and the anode adsorption material is a conductive material with adsorption ability.

4. The hexavalent chromium reduction, separation and synchronous monitoring device according to claim 1, characterized in that The cathode assembly (33) includes a cathode material, and the cathode material is based on a metal material or stainless steel.

5. A method for using a hexavalent chromium reduction, separation and synchronous monitoring device, based on the hexavalent chromium reduction, separation and synchronous monitoring device according to any one of the above claims 1-4, characterized in that, It includes the following steps: Obtain the polluted area, and analyze according to the regional location and pollutant distribution corresponding to the polluted area to generate a repair well setting area. Lay out repair wells in the repair well setting area. A corresponding hexavalent chromium reduction, separation and synchronous monitoring device is arranged in the repair well. The electrode system includes a cathode assembly (33) and an anode assembly (35). Form a supported cathode biofilm according to the cathode material of the cathode assembly (33), and introduce a preset electric potential into the cathode biofilm and the anode assembly (35) based on the control system to reduce and adsorb the content of hexavalent chromium in groundwater.

6. The method for using the hexavalent chromium reduction separation and synchronous monitoring device according to claim 5, characterized in that, The step of forming a supported cathode biofilm according to the cathode material of the cathode assembly (33) includes the following steps: Use the electrode material in the cathode assembly (33) as the anode, apply a first preset electric potential and operate for a first preset time to obtain an anode biofilm. Apply a second preset electric potential to the anode biofilm, perform bio - anode reversal and operate for a second preset time to obtain a cathode biofilm.

7. The method for using the hexavalent chromium reduction, separation and synchronous monitoring device according to claim 5, characterized in that, The cathode assembly (33) includes a cathode material. Before forming a supported cathode biofilm according to the cathode material of the cathode assembly (33), it also includes the following steps: Place the cathode material in acetone, ethanol, and deionized water for ultrasonic cleaning treatment for a third preset time to obtain a preliminarily cleaned material. Place the preliminarily cleaned material in a tube furnace and process it in a first preset reduction atmosphere to obtain a first reduced material. Process the first reduced material in a second preset reduction atmosphere to obtain a second reduced material. Cool the second reduced material to room temperature in pure helium to achieve surface carbon coating modification of the cathode material. Among them, in the first preset reduction atmosphere, the ratio of hydrogen to helium is 3:

1.

8. The method for using the hexavalent chromium reduction, separation and synchronous monitoring device according to claim 7, characterized in that, The first reduction material is processed in a second preset reduction atmosphere to obtain a second reduction material, wherein the generation method of the second reduction material includes the following steps; The first reduction material is placed in a mixed gas of hydrogen, helium and methane, and the growth temperature is a first preset temperature, and the first reduction material is grown in a second preset reduction atmosphere for a fourth preset time; Among them, the ratio of hydrogen, helium and methane in the second preset reduction atmosphere is 1:4:

1.

9. The method for using the hexavalent chromium reduction, separation and synchronous monitoring device according to claim 5, characterized in that The control system includes an electronic monitoring display (10). After the cathode biofilm and the anode assembly (35) are applied with a preset electric potential based on the control system, the following steps are included: Regularly obtain the absolute value of the open circuit and judge whether the absolute value of the open circuit is lower than a preset value; If the absolute value of the open circuit is lower than the preset value, a toxicity pollution signal is generated, and the adsorption quantity is obtained based on the toxicity pollution signal; Compare the adsorption quantity with a preset quantity and judge whether the adsorption quantity exceeds the preset quantity; If the adsorption quantity exceeds the preset quantity, a filler replacement signal is generated and the filler replacement signal is sent to the electronic monitoring display (10).

10. The method for using the hexavalent chromium reduction, separation and synchronous monitoring device according to claim 9, characterized in that, Judging whether the absolute value of the open circuit is lower than a preset value, the preset value is 20% - 50% of the absolute value of the potential, wherein the obtaining method of the absolute value of the potential includes the following steps: The sleeve electrode system is energized in a preset energization mode, and the open circuit potential signal generated by the biocathode is obtained, and the absolute value of the potential is obtained based on the open circuit potential signal.

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