Porous carbon-based electrode material and preparation method, high-salt mine water treatment system

Abstract

The application discloses a kind of porous carbon-based electrode materials and preparation method, high-salt mine water treatment system, belong to high-salt mine water treatment technical field, to solve the conductivity of active carbon in prior art insufficiently affect the processing efficiency and processing effect of high-salt mine water problem.The preparation method of the present application includes that sucrose, melamine, potassium chloride and sodium chloride are mixed and ground sufficiently, to obtain uniformly mixed powder;The mixed powder is heated and kept warm, and water vapor is introduced for surface etching during the keeping warm process, to obtain carbon-based material;The carbon-based material is cleaned;Concentrated nitric acid is used to stir and soak the cleaned carbon-based material, and after filtration separation, washing and drying, a porous carbon-based electrode material is obtained.The present application can be used for the treatment of high-salt mine water.

Description

Technical Field

[0001] This invention belongs to the field of high-salinity mine water treatment technology, and particularly relates to a porous carbon-based electrode material (i.e., water vapor activated nitrogen-doped porous carbon-based electrode material) and its preparation method, as well as a high-salinity mine water treatment system. Background Technology

[0002] High-salt mine water is an unconventional water resource. It has a high salt content and its mineralization is usually much higher than that of ordinary surface water or groundwater, sometimes reaching as high as 30,000 mg / L.

[0003] Flow electrode capacitive deionization technology is applied to the treatment of high-salinity mine water, and has the advantages of high deionization capacity, excellent environmental adaptability and batch wastewater treatment capability.

[0004] Traditional flow electrode materials are mostly carbon-based materials (e.g., activated carbon). However, activated carbon has insufficient conductivity, which affects the treatment efficiency and effect of high-salt mine water. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a porous carbon-based electrode material and its preparation method, as well as a high-salt mine water treatment system, to solve the problem that the insufficient conductivity of activated carbon in the prior art affects the treatment efficiency and effect of high-salt mine water.

[0006] The objective of this invention is mainly achieved through the following technical solutions.

[0007] This invention provides a method for preparing a porous carbon-based electrode material, comprising the following steps:

[0008] Step 1: Mix sucrose, melamine, potassium chloride and sodium chloride thoroughly and grind them to obtain a uniformly mixed powder;

[0009] Step 2: Heat and keep the mixed powder at a certain temperature. During the heat preservation process, water vapor is introduced to perform surface etching to obtain carbon-based materials.

[0010] Step 3: Clean the carbon-based materials;

[0011] Step 4: The cleaned carbon-based material is stirred and soaked with concentrated nitric acid, filtered and separated, washed and dried to obtain porous carbon-based electrode material.

[0012] Furthermore, in step 1, the mass ratio of sucrose, melamine, potassium chloride, and sodium chloride is 1:1.8-2.1:1.8-2.1:1.8-2.1.

[0013] Furthermore, in step 1, the grinding time is 1.0 to 1.5 hours.

[0014] Furthermore, in step 2, the heating and heat preservation process includes the following steps:

[0015] Pre-activation is performed by raising the temperature from room temperature to 220–280℃ for 1–2 hours, followed by raising the temperature to 650–750℃ and holding for 1.5–2.5 hours at a rate of 8–11℃ / min.

[0016] Furthermore, in step 2, the flow rate of water vapor is 0.8–1.1 g / min.

[0017] Furthermore, in step 4, the stirring and soaking time is 8–12 hours.

[0018] Furthermore, in step 4, the drying temperature is 70–80°C, and the drying time is 20–24 hours.

[0019] Furthermore, in step 4, the mass concentration of concentrated nitric acid is 50-65%.

[0020] The present invention also provides a porous carbon-based electrode material, which is prepared by the above-described method for preparing porous carbon-based electrode materials.

[0021] The present invention also provides a treatment system for high-salinity mine water, including an anode flow electrode and a cathode flow electrode. The composition of the anode flow electrode and the cathode flow electrode includes, by mass percentage, 2-5% porous carbon-based electrode material and 0.5-1.2% superconducting carbon black, with the balance being electrolyte. The porous carbon-based electrode material is the aforementioned porous carbon-based electrode material.

[0022] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects.

[0023] In the preparation method of the porous carbon-based electrode material provided by this invention, sucrose is used as the carbon source, melamine as the nitrogen source, and potassium chloride and sodium chloride as template agents. On the one hand, introducing nitrogen atoms into the carbon matrix can not only increase the defect states of the carbon-based material, but also adjust the electronic structure of the porous carbon-based electrode material by forming CN bonds, providing more transport channels for electrons and significantly improving the conductivity of the porous carbon-based electrode material. High conductivity can accelerate the electron transport rate in the flow electrode, thereby improving the reaction rate and overall performance of the flow electrode.

[0024] In the preparation method of the porous carbon-based electrode material provided by this invention, at high temperature, the interaction between water vapor and the carbon-based material effectively removes disordered carbon and volatile impurities from the carbon-based material. At the same time, it generates abundant micropores and mesopores. These porous structures not only increase the specific surface area of ​​the porous carbon-based electrode material, providing more active sites for electrochemical reactions, but also improve the transport paths of ions and electrons and reduce transport impedance. In addition, the porous structure also helps to buffer the volume expansion of the flow electrode during the charging and discharging process, improving the structural stability of the flow electrode.

[0025] In the preparation method of porous carbon-based electrode material provided by the present invention, nitric acid activation can introduce oxygen-containing functional groups such as hydroxyl, carboxyl and carbonyl groups on the surface of carbon-based material. These functional groups can increase the surface polarity of porous carbon-based electrode material. At the same time, the acid washing process will generate micropore and nanopore structures on the surface of carbon-based material, thereby increasing its specific surface area and helping to improve the adsorption capacity.

[0026] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0027] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0028] Figure 1 A schematic flowchart illustrating the preparation method of the porous carbon-based electrode material provided by the present invention;

[0029] Figure 2 A schematic diagram of the high-salinity mine water treatment system provided by the present invention;

[0030] Figure 3 An exploded view of the flow electrode capacitor deionization component in the high-salt mine water treatment system provided by the present invention.

[0031] Figure 4 A schematic diagram of the outlet pipe in the high-salt mine water treatment system provided by the present invention;

[0032] Figure 5a This is a low-power scanning electron microscope image of H2O(g)-NaCl-HNO3 / CN prepared in Example 1;

[0033] Figure 5b This is a high-power scanning electron microscope image of H2O(g)-NaCl-HNO3 / CN prepared in Example 1;

[0034] Figure 6a This is a low-power scanning electron microscope image of H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1.

[0035] Figure 6b This is a high-power scanning electron microscope image of H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1;

[0036] Figure 7a This is a low-power scanning electron microscope image of NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2.

[0037] Figure 7b This is a high-power scanning electron microscope image of NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2;

[0038] Figure 8a The image is a low-power scanning electron microscope image of H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3.

[0039] Figure 8b High-power scanning electron microscope image of H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3;

[0040] Figure 9 X-ray diffraction patterns of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3.

[0041] Figure 10 Raman spectra of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3;

[0042] Figure 11a The nitrogen adsorption-desorption curves are shown for H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3.

[0043] Figure 11b The pore size distribution diagrams are shown for H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3.

[0044] Figure 12Cyclic voltammetry curves of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 at a scan rate of 5 mV / s;

[0045] Figure 13 The constant current charge-discharge curves of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 at a current density of 0.5 A / g are shown.

[0046] Figure 14 This is a graph showing the change in the amount of salt removed from the system after seven adsorption-desorption cycles of H2O(g)-NaCl-HNO3 / CN prepared in Example 1;

[0047] Figure 15a The changes in the conductivity of FCDI were compared between H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3.

[0048] Figure 15b The changes in FCDI current of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 are compared.

[0049] Figure label:

[0050] 1-Anode flowing electrode tank; 2-Cathode flowing electrode tank; 3-High-salt mine water tank; 4-Purified water tank; 5-Flowing electrode capacitor deionization assembly; 51-Anode side end plate; 52-Anode side manifold; 53-Cation exchange membrane; 54-Treatment liquid chamber plate; 55-Anion exchange membrane; 56-Cathode side manifold; 57-Cathode side end plate; 58-Treatment liquid inlet pipe; 59-Treatment liquid outlet pipe; 510-Anode side flowing electrode inlet pipe; 511-Anode 512-Cathode side flow electrode outlet pipe; 513-Cathode side flow electrode inlet pipe; 514-Gasket; 6-Anode peristaltic pump; 7-Cathode peristaltic pump; 8-Mine water peristaltic pump; 9-Conductivity meter; 10-Power supply; 11-L-shaped mounting rod; 12-Drive gear; 13-Water outlet pipe; 131-First pipe body; 132-Second pipe body; 133-Flange; 14-Drive rack; 15-Inner brush; 16-Outer brush. Detailed Implementation

[0051] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0052] This invention provides a method for preparing porous carbon-based electrode materials, see [link to relevant documentation]. Figure 1 It includes the following steps:

[0053] Step 1: Place sucrose, melamine, potassium chloride and sodium chloride in an agate mortar and grind them thoroughly for 1.0 to 1.5 hours to obtain a uniformly mixed powder;

[0054] Step 2: Place the mixed powder in a ceramic boat and put the ceramic boat into a tube furnace. Heat and keep it warm. During the heat preservation process, water vapor is introduced to perform surface etching (when introducing water vapor, pay attention to wrapping the front end of the pipe with quartz wool to prevent the water vapor from condensing and liquefying in advance) to obtain carbon-based material (i.e. H2O(g)-NaCl / CN material).

[0055] Step 3: After cooling the carbon-based material to room temperature, wash it with deionized water to remove residual potassium chloride and sodium chloride from the carbon-based material;

[0056] Step 4: The cleaned carbon-based material is stirred and soaked with concentrated nitric acid (mass concentration of 50-65%). After filtration and separation, the solid part is washed with deionized water until neutral and then dried in an oven to obtain porous carbon-based electrode material (H2O(g)-NaCl-HNO3 / CN).

[0057] In the preparation method of the porous carbon-based electrode material provided by this invention, sucrose is used as the carbon source, melamine as the nitrogen source, and potassium chloride and sodium chloride as template agents. On the one hand, introducing nitrogen atoms into the carbon matrix can not only increase the defect states of the carbon-based material, but also adjust the electronic structure of the porous carbon-based electrode material by forming CN bonds, providing more transport channels for electrons and significantly improving the conductivity of the porous carbon-based electrode material. High conductivity can accelerate the electron transport rate in the flow electrode, thereby improving the reaction rate and overall performance of the flow electrode.

[0058] On the other hand, at high temperatures, the interaction between water vapor and carbon-based materials effectively removes disordered carbon and volatile impurities from the carbon-based materials. At the same time, it generates abundant microporous and mesoporous structures. These porous structures can not only increase the specific surface area of ​​porous carbon-based electrode materials, providing more active sites for electrochemical reactions, but also improve the transport paths of ions and electrons and reduce transport impedance. In addition, the porous structure also helps to buffer the volume expansion of the flow electrode during the charging and discharging process, thereby improving the structural stability of the flow electrode.

[0059] On the other hand, nitric acid activation can introduce oxygen-containing functional groups such as hydroxyl, carboxyl and carbonyl groups on the surface of carbon-based materials. These functional groups can increase the surface polarity of porous carbon-based electrode materials. At the same time, the acid washing process will generate micropores and nanopore structures on the surface of carbon-based materials, thereby increasing their specific surface area and helping to improve the adsorption capacity.

[0060] To ensure the porosity and conductivity of the obtained porous carbon-based electrode material, in step 1 above, the mass ratio of sucrose, melamine, potassium chloride, and sodium chloride is 1:1.8–2.1:1.8–2.1:1.8–2.1. By limiting the mass ratio of these four components within the aforementioned range, both the porosity and conductivity of the porous carbon-based electrode material can be guaranteed simultaneously.

[0061] To ensure that sucrose, melamine, potassium chloride, and sodium chloride are fully activated and to improve the porosity and conductivity of the obtained carbon-based material, the heating and holding process in step 2 above includes the following steps:

[0062] Pre-activation is performed by raising the temperature from room temperature to 220–280℃ for 1–2 hours, followed by raising the temperature to 650–750℃ and holding for 1.5–2.5 hours at a rate of 8–11℃ / min.

[0063] In order to ensure sufficient etching of the material surface, the flow rate of water vapor in step 2 above is 0.8 to 1.1 g / min.

[0064] To ensure sufficient activation of the carbon-based materials, the stirring and soaking time in step 4 above is 8 to 12 hours.

[0065] Similarly, in order to ensure that the porous carbon-based electrode material is thoroughly dried, the drying temperature in step 4 above is 70-80°C and the drying time is 20-24 hours.

[0066] The present invention also provides a porous carbon-based electrode material, which is prepared by the above-described method for preparing porous carbon-based electrode materials.

[0067] Compared with the prior art, the beneficial effects of the porous carbon-based electrode material provided by the present invention are basically the same as the beneficial effects of the preparation method of the porous carbon-based electrode material provided above, and will not be described in detail here.

[0068] This invention also provides a treatment system for high-salinity mine water, see [link to relevant documentation]. Figure 2 It includes an anode flow electrode and a cathode flow electrode, both of which have the same composition. By mass percentage, each electrode contains 2-5% porous carbon-based electrode material and 0.5-1.2% superconducting carbon black, with the balance being an electrolyte, such as a 1 g / L NaCl solution. The porous carbon-based electrode material is the porous carbon-based electrode material provided above.

[0069] Compared with the prior art, the beneficial effects of the high-salt mine water treatment system provided by the present invention are basically the same as those of the porous carbon-based electrode material provided above, and will not be elaborated here.

[0070] It is understood that the above-mentioned high-salt mine water treatment system also includes an anode flow electrode tank 1, a cathode flow electrode tank 2, a high-salt mine water tank 3, a purified water tank 4, and a flow electrode capacitor deionization assembly 5. The flow electrode capacitor deionization assembly 5 includes an anode-side current collector 52 (e.g., a graphite current collector), a cation exchange membrane 53, a treatment liquid chamber plate 54, an anion exchange membrane 55, and a cathode-side current collector 56 (e.g., a graphite current collector) stacked in sequence. The anode flow electrode tank 1 and the anode-side current collector 52 are connected to form an anode flow electrode circulation loop, and the cathode flow electrode tank 2 and the cathode-side current collector 56 are connected to form a cathode flow electrode circulation loop. The high-salt mine water tank 3, the treatment liquid chamber plate 54, and the purified water tank 4 are connected in sequence to form a high-salt mine water and purified water circulation loop.

[0071] Compared with the prior art, the high-salinity mine water treatment system provided by the present invention adopts a flow electrode capacitor deionization component 5 (i.e., FCDI component). During the treatment of high-salinity mine water, the high-salinity mine water, the anode flow electrode, and the cathode flow electrode are always in a flowing state. The uninterrupted treatment of high-salinity mine water effectively improves the treatment efficiency, thereby enabling long-term and large-scale treatment of high-salinity mine water. At the same time, since the anode-side current collector 52 can continuously adsorb cations, reducing the cation concentration in the anode flow electrode, and the cathode-side current collector 56 can continuously adsorb anions, reducing the anion concentration in the cathode flow electrode, the ion removal effect can be enhanced.

[0072] It is understandable that, in order to promote the flow of the anode flowing electrode, an anode peristaltic pump 6 is provided on the connecting pipe between the anode flowing electrode tank 1 and the anode side manifold 52, and the anode peristaltic pump 6 provides the flow power of the anode flowing electrode.

[0073] Similarly, in order to promote the flow of the cathode flowing electrode, a cathode peristaltic pump 7 is provided on the connecting pipe between the cathode flowing electrode tank 2 and the cathode side manifold 56, and the cathode peristaltic pump 7 provides the flow power of the cathode flowing electrode.

[0074] In order to promote the flow of high-salt mine water, a mine water peristaltic pump 8 is provided on the connecting pipeline between the high-salt mine water tank 3 and the treatment liquid chamber plate 54, and the mine water peristaltic pump 8 provides the flow power of high-salt mine water.

[0075] In order to understand the salt concentration of the mine water in the high-salt mine water tank 3 in real time, the above-mentioned high-salt mine water treatment system also includes a conductivity meter 9. The detection end of the conductivity meter 9 is inserted below the surface of the mine water in the high-salt mine water tank 3 to detect the change in conductivity of the high-salt mine water in real time, thereby knowing the change in its salt concentration.

[0076] For example, regarding the structure of the flow electrode capacitor deionization assembly 5, see [link to documentation]. Figure 3It also includes a treatment liquid inlet pipe 58, a treatment liquid outlet pipe 59, an anode-side flow electrode inlet pipe 510, an anode-side flow electrode outlet pipe 511, a cathode-side flow electrode inlet pipe 512, and a cathode-side flow electrode outlet pipe 513. The treatment liquid inlet pipe 58 and the treatment liquid outlet pipe 59 are respectively located on the end face of the treatment liquid chamber plate 54 and communicate with the inner cavity of the treatment liquid chamber plate 54. The anode-side flow electrode inlet pipe 510 and the anode-side flow electrode outlet pipe 511 are located on the side surface of the anode-side manifold 52 and communicate with the anode-side flow channel in the anode-side manifold 52. The cathode-side flow electrode inlet pipe 512 and the cathode-side flow electrode outlet pipe 513 are located on the side surface of the cathode-side manifold 56 and communicate with the cathode-side flow channel in the cathode-side manifold 56. The flow electrode capacitor deionization assembly 5 with this structure changes the original pipeline arrangement. On the one hand, the treatment liquid inlet pipe 58 and the treatment liquid outlet pipe 59 are respectively set on the end face of the treatment liquid chamber plate 54. The thickness of the treatment liquid chamber plate 54 no longer needs to take into account the treatment liquid inlet pipe 58 and the treatment liquid outlet pipe 59, thereby greatly reducing the thickness of the treatment liquid chamber plate 54. This, in turn, can reduce the distance between the anode side current collector 52 and the cathode side current collector 56, effectively improving the treatment efficiency. On the other hand, the anode-side flow electrode inlet pipe 510 and the anode-side flow electrode outlet pipe 511 are located on the side surface of the anode-side manifold 52, and the cathode-side flow electrode inlet pipe 512 and the cathode-side flow electrode outlet pipe 513 are located on the side surface of the cathode-side manifold 56. The liquid inlet and outlet directions of the anode-side flow electrode are parallel to the anode-side manifold 52, and the liquid inlet and outlet directions of the cathode-side flow electrode are parallel to the cathode-side manifold 56. The flow resistance of the flow electrode is greatly reduced, which can effectively reduce the blockage of the anode-side flow channel of the anode-side manifold 52 and the cathode-side flow channel of the cathode-side manifold 56.

[0077] In order to improve the overall structural strength of the above-mentioned flow electrode capacitor deionization assembly 5, the above-mentioned flow electrode capacitor deionization assembly 5 also includes an anode side end plate 51 and a cathode side end plate 57. The anode side end plate 51 is located on the side of the anode side current collector 52 away from the cation exchange membrane 53, and the cathode side end plate 57 is located on the side of the cathode side current collector 56 away from the anion exchange membrane 55. Multiple plates are sandwiched between the anode side end plate 51 and the cathode side end plate 57, thereby improving the overall structural strength of the flow electrode capacitor deionization assembly 5.

[0078] In order to seal and buffer between the various components, the above-mentioned high-salt mine water treatment system also includes a gasket 514, which is respectively disposed between the anode side end plate 51 and the anode side collector plate 52, between the anode side collector plate 52 and the cation exchange membrane 53, between the cation exchange membrane 53 and the treatment liquid chamber plate 54, between the treatment liquid chamber plate 54 and the anion exchange membrane 55, between the anion exchange membrane 55 and the cathode side collector plate 56, and between the cathode side collector plate 56 and the cathode side end plate 57.

[0079] Understandably, in order to form an electric field, the above-mentioned high-salt mine water treatment system also includes a power supply 10. The positive terminal of the power supply 10 is connected to the anode-side current collector 52 and / or the anode-side end plate 51, and the negative terminal of the power supply 10 is connected to the cathode-side current collector 56 and / or the cathode-side end plate 57.

[0080] It is worth noting that some impurities are inevitably present in high-salt mine water, which can easily cause blockage of the outlet pipe of the high-salt mine water tank. However, since the outlet pipe extends below the surface of the high-salt mine water, cleaning requires suspending the treatment of the high-salt mine water, which is a complicated process. In this invention, the outlet pipe 13 is a telescopic pipe, which includes a first pipe body 131 and a second pipe body 132. The second pipe body 132 is sleeved on the outer wall of the first pipe body 131 and is slidably and sealingly connected to the first pipe body 131. The first pipe body 131 is located outside the tank of the high-salt mine water tank. The second pipe body 132 is provided with a flange 133 at one end near the first pipe body 131. The second pipe body 132 is located inside the tank of the high-salt mine water tank, and the flange 133 is located outside the tank of the high-salt mine water tank.

[0081] The aforementioned high-salinity mine water treatment system also includes a dredging component, which includes an internal pipe brush 15. The brush rod end of the internal pipe brush 15 is fixedly connected to the first pipe body 131, and the bristle end of the internal pipe brush 15 protrudes into the second pipe body 132. The bristles of the internal pipe brush 15 contact the inner wall of the second pipe body 132. (See [reference]) Figure 4 In this way, by reciprocatingly pulling the flange 133, the operator causes the second tube 132 to move relative to the first tube 131, and the brush 15 inside the tube can scrub the inner wall of the second tube 132.

[0082] To clean the inlet end of the outlet pipe, the aforementioned unblocking assembly also includes an external brush 16, a drive rack 14, a drive gear 12, and an L-shaped mounting rod 11. The drive rack 14 is located on the outer wall of the second pipe body 132, and the drive gear 12 meshes perpendicularly with the drive rack 14. One end of the L-shaped mounting rod 11 is fixedly connected to the drive gear 12, and the other end of the L-shaped mounting rod 11 is fixedly connected to the brush rod end of the external brush 16. The other end of the external brush 16 is located below the inlet end of the outlet pipe and is in contact with the inlet end of the outlet pipe. Thus, when the second pipe body 132 reciprocates up and down, it drives the rack to reciprocate up and down, which in turn drives the drive gear 12 to rotate and the L-shaped mounting rod 11 to swing, causing the external brush 16 to swing back and forth relative to the inlet end of the outlet pipe, thereby cleaning the inlet end of the outlet pipe.

[0083] Example 1

[0084] The preparation method of the water vapor activated nitrogen-doped porous carbon-based electrode material in this embodiment is carried out according to the following steps:

[0085] (1) Weigh out sucrose, melamine, potassium chloride, and sodium chloride at mass ratios of 10g, 20g, 20g, and 20g respectively, and grind them in an agate mortar for 1 hour to obtain a uniformly mixed sample. Place the mixed sample in a porcelain boat and put it into a tube furnace. Set the tube furnace program to pre-activate from room temperature to 280℃ for 1 hour, then raise it to 750℃ and hold it for 2 hours. Set the heating rate to 10℃ / min for both times. During the holding process, introduce water vapor to etch the surface of the material. The water vapor flow rate is 1g / min. Take out the H2O(g)-NaCl / CN after carbonization and cooling to room temperature, and wash away the residual salt in the material with deionized water. Wash until the conductivity of the filtrate is <5μm / cm, which is considered as clean.

[0086] (2) H2O(g)-NaCl / CN was stirred and soaked in 50% nitric acid for 12 hours. After soaking, the sample was filtered and washed with deionized water until neutral. It was then dried in an oven at 80°C for 24 hours to obtain H2O(g)-NaCl-HNO3 / CN.

[0087] Electron microscopy images of the microstructure of the prepared H2O(g)-NaCl-HNO3 / CN are shown below. Figure 5a and Figure 5b As shown, it exhibits numerous hierarchical channels and a unique, neatly arranged mesh-like honeycomb structure, with a large amount of C, N, and O elements evenly distributed on the material surface.

[0088] Example 2

[0089] The preparation method of the water vapor activated nitrogen-doped porous carbon-based electrode material in this embodiment is carried out according to the following steps:

[0090] (1) Weigh out sucrose, melamine, potassium chloride, and sodium chloride at mass ratios of 10g, 18g, 18g, and 18g respectively, and grind them in an agate mortar for 1.5 hours to obtain a uniformly mixed sample. Place the mixed sample in a porcelain boat and put it into a tube furnace. Set the tube furnace program to pre-activate from room temperature to 230℃ for 2 hours, then raise it to 650℃ and hold it for 2.5 hours. Set the heating rate to 8℃ / min for both times. During the holding process, introduce water vapor to etch the surface of the material. The water vapor flow rate is 0.8g / min. Take out the H2O(g)-NaCl / CN after carbonization and cooling to room temperature, and wash away the residual salt in the material with deionized water. Wash until the conductivity of the filtrate is <5μm / cm, which is considered as clean.

[0091] (2) H2O(g)-NaCl / CN was stirred and soaked in 60% nitric acid for 8 hours. After soaking, the sample was filtered and washed with deionized water until neutral. It was then dried in a 70℃ oven for 20 hours to obtain H2O(g)-NaCl-HNO3 / CN.

[0092] Comparative Example 1

[0093] The difference between this comparative example and Example 1 is that the acid washing and activation in step (2) is replaced by soaking in deionized water, while the other steps and parameters are the same as in Example 1. The resulting electrode material is abbreviated as H2O(g)-NaCl-H2O / CN.

[0094] Electron microscopy images of the microstructure of the prepared H2O(g)-NaCl-H2O / CN are shown below. Figure 6a and Figure 6b As shown, the material exhibits a uniform distribution of hierarchical pores, with macropores, mesopores, and micropores all present. However, under magnification, the micropore arrangement appears disordered and irregular. The lack of acid leaching treatment allows impurities such as undeposited salt templates to affect the pore structure. C, N, and O elements are distributed on the material surface.

[0095] Comparative Example 2

[0096] The difference between this comparative example and Example 1 is that the water vapor activation etching in step (1) is omitted, while the other steps and parameters are the same as in Example 1. The resulting electrode material is simply referred to as NH2O(g)-NaCl-HNO3 / CN.

[0097] Electron microscopy images of the microstructure of the prepared NH2O(g)-NaCl-HNO3 / CN are shown below. Figure 7a and Figure 7b As shown, the material exhibits a denser structure with fewer pores, and its surface is smoother than that of Example 1 and Comparative Example 2. The number of hierarchical pores is reduced, and the formation of the pore structure is limited by the lack of water vapor-activated etching. C, N, and O elements are distributed on the surface of the material.

[0098] Comparative Example 3

[0099] The difference between this comparative example and Example 1 is that the template agent material in step (1) is replaced by zinc chloride with sodium chloride, while the other steps and parameters are the same as in Example 1. The resulting electrode material is simply referred to as H2O(g)-ZnCl2-HNO3 / CN.

[0100] Electron microscopy images of the microstructure of the prepared H2O(g)-ZnCl2-HNO3 / CN are shown below. Figure 8a and Figure 8b As shown, the material surface has relatively few pores. The zinc chloride template forms inclusions at high temperatures that are not prone to pore formation and are not easily removed during water washing and acid etching. C, N, and O elements are distributed on the material surface.

[0101] The X-ray diffraction patterns of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 are as follows: Figure 9 As shown, H2O(g)-NaCl-HNO3 / CN exhibits a more pronounced graphitized structure and a lower degree of disorder compared to the other three comparative examples. This structure is highly advantageous for conductivity and ion adsorption, and helps to improve the electrochemical performance in electroadsorption.

[0102] The Raman spectra of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 are shown below. Figure 10 As shown, H2O(g)-NaCl-HNO3 / CN exhibits a more pronounced graphitized structure and a lower degree of disorder compared to the other three comparative examples.

[0103] The BET surface area measurements of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 are as follows: Figure 11a and Figure 11b As shown, H2O(g)-NaCl-HNO3 / CN exhibits a higher specific surface area and superior microporous structure compared to the other three comparative examples.

[0104] The cyclic voltammetric curves of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 at a scan rate of 5 mV / s are shown below. Figure 12 As shown, the area under the CV curve of H2O(g)-NaCl-HNO3 / CN is much larger than that of the other three materials, and its good symmetry also indicates that the material has good and stable electrochemical performance.

[0105] The constant current charge-discharge curves of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 at a current density of 0.5 A / g are shown below. Figure 13 As shown, H2O(g)-NaCl-HNO3 / CN exhibits greater capacitance, lower resistance, and the strongest charge release capability compared to the other three comparative examples.

[0106] Example 3

[0107] The prepared electrode material was configured as a flow electrode and applied to a high-salinity mine water treatment system, as follows:

[0108] (1) Grind the active material with an agate mortar and pestle, and take the sieve-underfill portion after passing through a 200-mesh sieve; weigh 3wt% of the active material and 1wt% of the superconducting carbon black for the solid part, and select a 1g / L NaCl solution as the electrolyte. Mix the above solid and liquid parts thoroughly with a magnetic stirrer for 2h. After the material is fully wetted, a uniform suspension is obtained. Then place the suspension in an ultrasonic cleaner and sonicate for 2h to obtain a flow electrode.

[0109] (2) In the treatment system of high salinity mine water, the flow electrode capacitor deionization component adopts a short-circuit closed circulation mode, and 1 g / L NaCl treatment solution is pumped into the flow channel with a plate spacing of 0.5 mm at a flow rate of 3 mL / min. At the same time, the flow rate of the flow electrode is kept constant at 32.5 mL / min and the voltage is kept at 1.2 V.

[0110] The changes in the desalination capacity of the system after seven adsorption-desorption cycles of H2O(g)-NaCl-HNO3 / CN prepared in Example 1 are as follows: Figure 14 As shown, the desalination retention rate can still reach 95.71% after seven cycles, which indicates that the material has good regenerability and stable recycling performance.

[0111] The effects of H2O(g)-NaCl-HNO3 / CN prepared in Example 1, H2O(g)-NaCl-H2O / CN prepared in Comparative Example 1, NH2O(g)-NaCl-HNO3 / CN prepared in Comparative Example 2, and H2O(g)-ZnCl2-HNO3 / CN prepared in Comparative Example 3 on the desalination performance of FCDI are as follows: Figure 15a and Figure 15bAs shown, the H2O(g)-NaCl-HNO3 / CN material exhibits the most outstanding desalination performance. Its conductivity shows a significant decreasing trend with the extension of treatment time. The conductivity of this material decreases the fastest within the first 120 minutes. The desalination rate is 70.4% after two hours, and the desalination amount can reach 23.7 mg / g, highlighting its rapid response electrochemical kinetic characteristics.

[0112] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A system for treating high-salinity mine water, characterized by, The anode flow electrode and the cathode flow electrode comprise, by mass percentage, 2-5 of the porous carbon-based electrode material and 0.5-1.2 of superconducting carbon black, with the balance being electrolyte. The high-salt mine water treatment system further comprises an anode flow electrode tank, a cathode flow electrode tank, a high-salt mine water tank, a clean water tank and a flow electrode capacitive deionization assembly, the flow electrode capacitive deionization assembly comprises, in sequence, an anode-side current collector plate, a cation exchange membrane, a treatment liquid cavity plate, an anion exchange membrane and a cathode-side current collector plate, the anode flow electrode tank and the anode-side current collector plate are in communication to form an anode flow electrode circulation loop, the cathode flow electrode tank and the cathode-side current collector plate are in communication to form a cathode flow electrode circulation loop, the high-salt mine water tank, the treatment liquid cavity plate and the clean water tank are in sequence in communication to form a high-salt mine water and clean water circulation loop; the water outlet pipe of the high-salt mine water tank comprises a first pipe body and a second pipe body, the second pipe body is sleeved on the outer wall of the first pipe body and is in slidable sealed connection with the first pipe body, the first pipe body is located outside the tank body of the high-salt mine water tank, the second pipe body is located inside the tank body of the high-salt mine water tank, and a flange is arranged on the end of the second pipe body close to the first pipe body; the high-salt mine water treatment system further comprises a dredging assembly, the dredging assembly comprises an inner pipe brush, an outer pipe brush, a driving rack, a driving gear and an L-shaped mounting rod, the brush rod end of the inner pipe brush is fixedly connected with the first pipe body, the brush end of the inner pipe brush protrudes into the second pipe body, and the bristles of the inner pipe brush are in contact with the inner wall of the second pipe body; the driving rack is arranged on the outer wall of the second pipe body, the driving gear is in perpendicular engagement with the driving rack, one end of the L-shaped mounting rod is fixedly connected with the driving gear, and the other end of the L-shaped mounting rod is fixedly connected with the brush rod end of the outer pipe brush, and the other end of the outer pipe brush is located below the water inlet end of the water outlet pipe and is in contact with the water inlet end of the water outlet pipe.

2. The high-salinity mine water treatment system of claim 1, wherein, In step 1, the mass ratio of the sucrose, melamine, potassium chloride and sodium chloride is 1:1.8-2.1:1.8-2.1:1.8-2.

1.

3. The high-salinity mine water treatment system of claim 1, wherein, In step 1, the grinding time is 1.0-1.5 h.

4. The high-salinity mine water treatment system of claim 1, wherein, In step 2, the heating and temperature maintaining process comprises the following steps: pre-activation at a temperature of 220-280℃ for 1-2 h, then temperature maintaining at 650-750℃ for 1.5-2.5 h, and the temperature increasing rate is 8-11℃ / min.

5. The high-salinity mine water treatment system of claim 1, wherein, In step 2, the flow rate of the water vapor is 0.8-1.1 g / min.

6. The high-salinity mine water treatment system of claim 1, wherein, In step 4, the stirring and soaking time is 8-12 h.

7. The high-salinity mine water treatment system of claim 1, wherein, In step 4, the drying temperature is 70-80℃, and the drying time is 20-24 h.

8. The high-salinity mine water treatment system of claim 1, wherein, In the step 4, the mass concentration of the concentrated nitric acid is 50-65%. In the step 4, the mass concentration of the concentrated nitric acid is 50-65%.

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