Electrode plate, preparation method thereof and application of electrode plate in low-concentration rare earth ion recovery

Abstract

The invention provides an electrode plate and a preparation method and application thereof in low-concentration rare earth ion recovery, and belongs to the technical field of electrochemistry, the electrode plate comprises a conductor layer and an active layer, the active layer comprises a titanium phosphate composite electrode material, a conductive agent and an adhesive, the titanium phosphate composite electrode material comprises inner core particles and a shell layer from inside to outside, the inner core particles are conductive particles, and the shell layer is composed of titanium phosphate nanosheets. The electrode plate active layer adopted by the invention comprises a titanium phosphate composite electrode material, and titanium phosphate adsorbs rare earth ions on the titanium phosphate composite electrode material through chemical complexation; the conductive particles can improve the electrochemical performance of the titanium phosphate, improve the capacitance capacity of the titanium phosphate and reduce the internal resistance, and the titanium phosphate composite electrode material improves the recovery effect of the rare earth ions in the low-concentration rare earth leaching solution through coupling strengthening of the electric field effect.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, specifically to electrode plates and their preparation methods, and their application in the recovery of low-concentration rare earth ions. Background Technology

[0002] After iterations of pond leaching and heap leaching processes, in-situ leaching is now used to recover and utilize rare earth resources. The leaching agent seeps into the ore body through injection holes in the mountainside under gravity. During seepage, cations in the leaching agent exchange with rare earth ions, and the rare earth ions enter the solution. Subsequently, the rare earth ion solution is collected through guide holes for further processing. In-situ leaching has a strong long-tail effect, meaning that a large amount of low-concentration rare earth leachate continues to be generated for a long time after the mine is closed. However, conventional precipitation or adsorption processes cannot economically and effectively recover and utilize this low-concentration rare earth ion, leading to a significant waste of rare earth resources and serious environmental pollution. Therefore, developing a low-concentration rare earth ion recovery process is of great significance for improving the comprehensive utilization level of rare earth resources and maintaining the ecological environment safety of in-situ leaching areas.

[0003] Adsorption is one of the most suitable methods for treating low-concentration rare earth wastewater. Several patents (CN119569167A, CN117696016A, CN117531490A) have been developed to recover rare earth ions from low-concentration rare earth solutions.

[0004] However, in the development of traditional rare earth adsorbents, the adsorbents generally exhibit high adsorption capacity only under high concentration conditions, with poor adsorption performance at low concentrations. This is because rare earth ions have a strong hydration capacity, and the diffusion driving force of rare earth ions weakens under low concentration conditions, affecting the adsorption of rare earth ions on the adsorbent surface. Therefore, there is an urgent need to develop a method and adsorbent material that can effectively recover low-concentration rare earth ions. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides an electrode plate and its preparation method and its application in the recovery of low-concentration rare earth ions, aiming to solve the technical problem of poor adsorption capacity of adsorbent under low concentration conditions.

[0006] In a first aspect, embodiments of this application provide an electrode plate, including a conductor layer and an active layer. The active layer includes a titanium phosphate composite electrode material, a conductive agent, and a binder. The titanium phosphate composite electrode material includes, from the inside out, core particles and a shell layer. The core particles are conductive particles, and the shell layer is composed of titanium phosphate nanosheets.

[0007] In some embodiments, the conductive particles include at least one of activated carbon and carbon nanotubes.

[0008] In some embodiments, the conductive agent includes conductive carbon black.

[0009] In some embodiments, the adhesive includes at least one of polytetrafluoroethylene, polyimide, and polyvinyl butyral.

[0010] In some embodiments, the conductor layer includes at least one of a titanium plate, a stainless steel plate, a copper plate, and an aluminum plate.

[0011] In some embodiments, the particle size of the titanium phosphate composite electrode material is 10-15 μm, and the particle size of the conductive particles is 1-3 μm.

[0012] Secondly, embodiments of this application provide a method for preparing an electrode plate, comprising the following steps: S1. Conductive particles and tetrabutyl titanate are dispersed in anhydrous ethanol, phosphoric acid solution is added, and the mixture is heated and stirred in a water bath. After the reaction is completed, the mixture is filtered and freeze-dried to obtain titanium phosphate composite electrode material. S2. Add titanium phosphate composite electrode material, conductive agent and binder to solvent, grind and mix well to obtain active slurry; S3. Coat the active slurry onto the conductor layer and dry it to obtain the electrode plate.

[0013] In some embodiments, the mass ratio of conductive particles, tetrabutyl titanate, and phosphoric acid in step S1 is (1~5):(15~20):(60~80).

[0014] In some embodiments, the phosphoric acid solution has a mass fraction of 85%.

[0015] In some embodiments, the water bath heating temperature in step S1 is 40~70℃, and the stirring reaction time is 6~18h.

[0016] In some embodiments, the mass ratio of titanium phosphate composite electrode material, conductive agent and binder in step S2 is (8~6):(1~3):1.

[0017] Thirdly, embodiments of this application provide an application of an electrode plate in the recovery of low-concentration rare earth ions, comprising the following steps: At least one pair of electrode plates are placed in wastewater containing low concentrations of rare earth ions. Electrolysis is performed after the pair of electrode plates are connected to the positive and negative terminals of a DC power supply. The spacing between a pair of electrode plates is 2~9mm, and the electrolysis voltage is 0.6~1.5V; The electrode plate connected to the positive terminal of the DC power supply is the anode plate, and the electrode plate connected to the negative terminal of the DC power supply is the cathode plate. Rare earth ions are adsorbed on the cathode plate.

[0018] In some embodiments, after the rare earth ions on the cathode plate reach adsorption equilibrium, the cathode plate is placed in a hydrochloric acid solution for desorption.

[0019] The advantages of this application, which differ from existing technical solutions, include: 1. The active layer of the electrode plate used in this invention includes titanium phosphate composite electrode material. Titanium phosphate adsorbs rare earth ions onto the titanium phosphate composite electrode material through chemical complexation. Conductive particles can improve the electrochemical performance of titanium phosphate, increase its capacitance, and reduce its internal resistance. The titanium phosphate composite electrode material improves the recovery effect of rare earth ions in low-concentration rare earth leachate through coupling enhancement by electric field.

[0020] 2. This invention uses an electrochemical method to recover rare earth ions. During the electrolysis process, driven by the electric field, rare earth cations in the wastewater will move towards the cathode plate. Water molecules are less affected by the electric field and move towards the cathode plate at a slower rate. Therefore, rare earth cations will gradually separate from the water molecules adsorbed around them during the movement process, resulting in a significant reduction in the number of hydrated ions around the rare earth cations. This significantly reduces the degree of hydration of rare earth ions, which is beneficial for the adsorption of rare earth cations by the electrode plate.

[0021] The above description is merely an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0022] To more clearly illustrate the technical solution of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0023] Figure 1 This is a schematic diagram of the electrolytic cell structure in an embodiment of this application; Figure 2 This is a SEM scan of the titanium phosphate composite electrode material in Example 1 of this application; Figure 3 Examples 2-6 of this application show Gd at different concentrations. 3+ The detection results in the solution are shown in the figure. Figure 3 a represents the electrode plate at different times Gd 3+ Adsorption capacity variation graph Figure 3 b represents the electrode plates at different times. + Recovery rate change graph Figure 3 c represents Gd after the electrode plate reaches adsorption equilibrium. 3+Adsorption capacity and recovery rate graph; Figure 4 Examples 7-12 of this application illustrate the effect of electrode plates on Gd under different pH conditions. 3+ Adsorption capacity and recovery rate graph; Figure 5 Examples 13-17 of this application illustrate the electrode plates for Gd under different voltage conditions. 3+ Adsorption capacity and recovery rate graph; Figure 6 The electrode plate for Gd under different cycle numbers in Example 18 3+ Adsorption capacity and recovery rate graph; Figure 7 The images show the detection results of Examples 19 and 20, where... Figure 7 a represents the electrode plate at different times Gd 3+ Adsorption capacity variation graph Figure 7 b is a graph showing the change in recovery rate of the electrode plate at different times; Figure 8 The electrode plates in Example 6 and Comparative Examples 1-4 are used to apply Gd 3+ Adsorption capacity detection graph; Figure 9 The figures show the capacitance-voltage characteristic curves of the composite electrode material at different scan rates. Figure 9 a represents the capacitance-voltage characteristic curve of the titanium phosphate composite electrode material prepared in Example 1 of this application. Figure 9 b represents the capacitance-voltage characteristic curve of titanium phosphate material. Attached image description: 1. Electrolytic cell; 2. Electrode plate; 3. DC power supply; 4. Peristaltic pump. Detailed Implementation

[0025] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0027] Existing adsorption processes are ineffective for low-concentration rare earth ions. The adsorbent's adsorption capacity in low-concentration rare earth solutions is limited, and the residual concentration of rare earth ions remains high even after adsorption equilibrium is reached. This perpetuates the problem of low-concentration rare earth ion recovery, leading to the unresolved waste of important rare earth resources and environmental pollution. To address this issue, many researchers have opted to develop adsorbents with larger specific surface areas or more adsorption sites to overcome the poor recovery performance of rare earth ions under low-concentration conditions. However, high ion hydration levels and diffusion motives relying solely on concentration gradients are insufficient to support the effective adsorption of low-concentration rare earth ions on the adsorbent surface.

[0028] To address the technical problem of poor rare earth ion recovery performance under low concentration conditions, this application provides an electrode plate, its preparation method, and its application in the recovery of low-concentration rare earth ions. The method of electrochemical adsorption combined with chemical adsorption overcomes the problem of the inability of existing technologies to effectively recover low-concentration rare earth ions.

[0029] In a first aspect, embodiments of this application provide an electrode plate, including a conductor layer and an active layer. The active layer includes a titanium phosphate composite electrode material, a conductive agent, and a binder. The titanium phosphate composite electrode material includes, from the inside out, core particles and a shell layer. The core particles are conductive particles, and the shell layer is composed of titanium phosphate nanosheets.

[0030] In the technical solution of this application embodiment, an electrochemical method is used to treat low-concentration rare earth ion wastewater. The electrode plate is provided with a titanium phosphate composite electrode material as an active layer. The titanium phosphate composite electrode material consists of conductive particle core particles and titanium phosphate nanosheet shell layers. The titanium phosphate nanosheets are stacked into nanoflower-like clusters and tightly adhered to the surface of the conductive particles.

[0031] Titanium phosphate nanosheets not only give titanium phosphate composite electrode materials a large specific surface area and provide abundant reaction sites, allowing rare earth ions to be adsorbed onto the titanium phosphate composite electrode materials through chemical complexation; but the flower-like clusters formed also provide abundant micropores and mesopores, which are beneficial to the formation of the electric double layer on the electrode surface during electroadsorption.

[0032] The conductive particles in titanium phosphate composite electrode materials can improve the electrochemical performance of titanium phosphate, increase its capacitance, and reduce its internal resistance. For electrode materials, higher capacitance indicates that the double layer can store more ions; lower internal resistance indicates that there is less resistance to ion transport inside the electrode material and at the interface, allowing ions to enter the material more quickly and complete adsorption.

[0033] Titanium phosphate composite electrode materials enhance the recovery of rare earth ions in low-concentration rare earth leachates through coupling strengthening under the action of an electric field.

[0034] In some embodiments, the conductive particles include at least one of activated carbon and carbon nanotubes, preferably activated carbon. The conductive particles can optimize the electrochemical performance of titanium phosphate, improve its capacitance, reduce its internal resistance, and enhance the adsorption capacity of titanium phosphate for rare earth ions during the electrochemical process.

[0035] In some embodiments, the conductive agent includes conductive carbon black, which can improve the conductivity between titanium phosphate composite electrode materials.

[0036] In some embodiments, the adhesive includes at least one of polytetrafluoroethylene, polyimide, and polyvinyl butyral.

[0037] In some embodiments, the conductor layer includes at least one of a titanium plate, a stainless steel plate, a copper plate, and an aluminum plate, preferably a titanium plate.

[0038] In some embodiments, the particle size of the titanium phosphate composite electrode material is 10-15 μm, and the particle size of the conductive particles is 1-3 μm.

[0039] Secondly, embodiments of this application provide a method for preparing an electrode plate, comprising the following steps: S1. Conductive particles and tetrabutyl titanate are dispersed in anhydrous ethanol, phosphoric acid solution is added, and the mixture is heated and stirred in a water bath. After the reaction is completed, the mixture is filtered and freeze-dried to obtain titanium phosphate composite electrode material. S2. Add titanium phosphate composite electrode material, conductive agent and binder to solvent, grind and mix well to obtain active slurry; S3. Coat the active slurry onto the conductor layer and dry it to obtain the electrode plate.

[0040] In some embodiments, the mass ratio of conductive particles, tetrabutyl titanate, and phosphoric acid in step S1 is (1~5):(15~20):(60~80).

[0041] In some embodiments, the phosphoric acid solution has a mass fraction of 85%.

[0042] In some embodiments, the water bath heating temperature in step S1 is 40~70℃, and the stirring reaction time is 6~18h.

[0043] In some embodiments, the mass ratio of titanium phosphate composite electrode material, conductive agent and binder in step S2 is (8~6):(1~3):1.

[0044] Thirdly, embodiments of this application provide an application of an electrode plate in the recovery of low-concentration rare earth ions, comprising the following steps: like Figure 1As shown, at least one pair of electrode plates 2 are placed in an electrolytic cell 1 containing low-concentration rare earth ion wastewater. Electrolysis is performed after the electrode plates 2 are connected to the positive and negative terminals of a DC power supply 3. A peristaltic pump 4 is connected to the electrolytic cell 1, driving the low-concentration rare earth ion wastewater in the cell to circulate. The peristaltic pump 4 rotates at 40 r / min. During electrolysis, driven by the electric field, the rare earth cations in the wastewater move towards the cathode plate. Water molecules are less affected by the electric field and move towards the cathode plate more slowly. Therefore, the rare earth cations gradually separate from the water molecules adsorbed around them during their movement, resulting in a significant reduction in the number of hydrated ions around the rare earth cations. This significantly reduces the hydration level of the rare earth ions, which is beneficial for the adsorption of rare earth cations by the electrode plates.

[0045] In some embodiments, the spacing between a pair of electrode plates 2 is 2~9mm, and the electrolysis voltage is 0.6~1.5V.

[0046] In some embodiments, the electrode plate 2 connected to the positive terminal of the DC power supply 3 is an anode plate, and the electrode plate 2 connected to the negative terminal of the DC power supply 3 is a cathode plate, with rare earth ions adsorbed on the cathode plate.

[0047] After the rare earth ions on the cathode plate reach adsorption equilibrium, the cathode plate is placed in hydrochloric acid solution for desorption.

[0048] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0049] I. Preparation Method Example 1 A method for preparing an electrode plate includes the following steps: S1. Add 200 mL of anhydrous ethanol, 1 g of activated carbon, and 20 mL of tetrabutyl titanate to a jacketed beaker and heat in a water bath at 60 °C. After mechanical stirring for 1 hour, add 60 mL of 85% phosphoric acid solution and continue stirring in a 60 °C water bath for 10 hours. After the reaction is complete, filter the product and wash it several times with water. Finally, transfer the product to a freeze dryer and freeze-dry for 10 hours to obtain the activated carbon-titanium phosphate (AC-TiP) composite electrode material. Figure 2 As shown, titanium phosphate nanosheets are stacked into nanoflower-like clusters and tightly adhered to the surface of activated carbon.

[0050] S2. Add AC-TiP composite electrode material, conductive carbon black and PVDF to a beaker in a mass ratio of 8:1:1, add N,N dimethylformamide as a solvent, and stir for 24 hours to obtain a uniform slurry.

[0051] S3. Transfer the slurry into an airbrush and spray it evenly onto the conductive titanium plate. After drying the electrode plate, immerse it in pure water to remove excess impurities. After immersion for 12 hours, remove it, dry it, and obtain the electrode plate.

[0052] Examples 2-6 An electrode plate is used in the recovery of low-concentration rare earth ions, comprising the following steps: In Examples 2-6, 200 mL of Gd at concentrations of 2, 4, 6, 8, and 10 mg / L were taken respectively. 3+ The solution was placed in an electrolytic cell, and a pair of AC-TiP electrodes prepared in Example 1 were placed at 5 mm intervals. The cells were connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. Figure 1 As shown, the peristaltic pump speed is adjusted to 45 r / min to allow the Gd in the electrolytic cell to... 3+ The solution was circulated, and adsorption tests were conducted at room temperature.

[0053] Samples were taken at different times, and the concentration of Gd in the solution was determined by arsene III spectrophotometry. 3+ The residual concentration was used to calculate the adsorption capacity of the AC-TiP electrode plate. For example... Figure 3 As shown, using an electrochemically coupled chemisorption method with AC-TiP electrode plates, an adsorption capacity of 131.51 mg / g was achieved at an initial concentration of 10 mg / L. When the initial concentration was less than 10 mg / L, the recovery rate remained at around 95%, essentially achieving the desired recovery of Gd in solution. 3+ Recycling.

[0054] Examples 7-12 An electrode plate is used in the recovery of low-concentration rare earth ions, comprising the following steps: Take 200 mL of Gd at a concentration of 10 mg / L 3+ In the electrolytic cell, the pH of the solution was adjusted sequentially to 2, 3, 4, 5, 6, and 7 using HCl and NaOH, respectively, in Examples 7-12. A pair of AC-TiP electrodes prepared in Example 1 were placed at 5 mm intervals and connected to a DC power supply via electrode clamps. A constant voltage of 1.2V was set, and electrolysis was performed for 24 hours. The peristaltic pump speed was adjusted to 45 r / min, and adsorption experiments were conducted at room temperature.

[0055] The residual concentration in the solution was determined using the azoarsine III spectrophotometric method, and the adsorption capacity of the AC-TiP electrode was calculated. The results are as follows: Figure 4 As shown, Gd can be controlled over a wide pH range.3+ Effective recycling.

[0056] Examples 13-17 An electrode plate is used in the recovery of low-concentration rare earth ions, comprising the following steps: Take 200 mL of Gd at a concentration of 10 mg / L 3+ The solution was placed in an electrolytic cell. A pair of AC-TiP electrodes prepared in Example 1 were placed at 5 mm intervals and connected to a DC power supply via electrode clamps. In Examples 13-17, the voltages were set to 0.4, 0.8, 1.0, 1.2, and 1.4 V, respectively, and electrolysis was performed for 24 h. The peristaltic pump speed was adjusted to 45 r / min, and adsorption tests were conducted at room temperature.

[0057] The residual concentration in the solution was determined using the azoarsine III spectrophotometric method, and the adsorption capacity of the AC-TiP electrode was calculated. The results are as follows: Figure 5 As shown, the adsorption capacity of the AC-TiP electrode increases with increasing voltage, and reaches a basic equilibrium at 1.2V.

[0058] Example 18 An electrode plate is used in the recovery of low-concentration rare earth ions, comprising the following steps: Take 200 mL of Gd at a concentration of 10 mg / L 3+ The solution was placed in an electrolytic cell, and a pair of AC-TiP plates prepared in Example 1 were placed at 5 mm intervals. The cell was connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. After electrolysis, the plates were immersed in a 1 mol / L HCl solution for desorption for 1 hour. The adsorption / desorption experiments were then repeated using the same pair of plates.

[0059] After four cycles of adsorption / desorption, the results are as follows: Figure 6 As shown, it can still maintain good recovery effect and desorption performance after multiple cycles.

[0060] Example 19 An electrode plate is used in the recovery of low-concentration rare earth ions, comprising the following steps: Take 200 mL of Gd at a concentration of 20 mg / L 3+ The solution was placed in an electrolytic cell, and two pairs of AC-TiP plates prepared in Example 1 were placed at 5 mm intervals. The cells were connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. The peristaltic pump speed was adjusted to 45 r / min, and adsorption experiments were conducted at room temperature.

[0061] Example 20 An electrode plate is used in the recovery of low-concentration rare earth ions, comprising the following steps: Take 200 mL of Gd at a concentration of 90 mg / L3+ The solution was placed in an electrolytic cell, and five pairs of AC-TiP plates prepared in Example 1 were placed at 5 mm intervals. The cells were connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. The peristaltic pump speed was adjusted to 45 r / min, and adsorption experiments were conducted at room temperature.

[0062] Gd in the electrolytic cells of Examples 19 and 20 3+ The solution was sampled at regular intervals, and the residual concentration in the solution was determined using the arsene III spectrophotometric method. The adsorption capacity and recovery rate of the AC-TiP electrode were calculated. The results are as follows: Figure 7 As shown, a multi-plate strategy can be used to control high concentrations of Gd. 3+ Effective recycling.

[0063] Comparative Example 1 Activated carbon, conductive carbon black, and PVDF were added to a beaker in a mass ratio of 8:1:1, with N,N dimethylformamide added as a solvent. The mixture was stirred for 24 hours to obtain a homogeneous slurry. The slurry was transferred to an airbrush and evenly sprayed onto a titanium substrate. After drying the electrode plate, it was immersed in pure water to remove excess impurities. After immersion for 12 hours, it was removed and dried to obtain the activated carbon electrode plate.

[0064] Take 200 mL of Gd at a concentration of 10 mg / L 3+ The solution was placed in an electrolytic cell, with a pair of activated carbon electrode plates spaced 5 mm apart. The cell was connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. The peristaltic pump speed was adjusted to 45 r / min, and adsorption experiments were conducted at room temperature.

[0065] Comparative Example 2 Take 200 mL of Gd at a concentration of 10 mg / L 3+ The solution was placed in an electrolytic cell. A pair of AC-TiP plates prepared in Example 1 were placed at 5 mm intervals, and the reaction was allowed to proceed for 24 hours without an external voltage. The peristaltic pump speed was adjusted to 45 r / min, and adsorption tests were conducted at room temperature.

[0066] Comparative Example 3 Take 200 mL of Gd at a concentration of 10 mg / L 3+ The solution was placed in an electrolytic cell with a pair of titanium plates spaced 5 mm apart. The cell was connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. The peristaltic pump speed was adjusted to 45 r / min, and adsorption experiments were conducted at room temperature.

[0067] Comparative Example 4 Titanium phosphate, conductive carbon black, and PVDF were added to a beaker in a mass ratio of 8:1:1, with N,N dimethylformamide added as a solvent. The mixture was stirred for 24 hours to obtain a homogeneous slurry. The slurry was transferred to an airbrush and evenly sprayed onto a titanium substrate. After drying the electrode plate, it was immersed in pure water to remove excess impurities. After immersion for 12 hours, it was removed and dried to obtain an activated carbon electrode plate.

[0068] Take 200 mL of Gd at a concentration of 10 mg / L 3+ The solution was placed in an electrolytic cell, with a pair of titanium phosphate electrode plates spaced 5 mm apart. The cell was connected to a DC power supply via electrode clamps, and a constant voltage of 1.2 V was set for electrolysis for 24 hours. The peristaltic pump speed was adjusted to 45 r / min, and adsorption experiments were conducted at room temperature.

[0069] Gd in the solutions after the adsorption tests in Example 6 and Comparative Examples 1-4 was determined by azoarsine III spectrophotometry. 3+ The residual concentration was used to calculate the adsorption capacity of the AC-TiP plate, and the results are as follows: Figure 8 As shown. From Figure 8 As can be seen, the titanium phosphate composite electrode material used in Example 6 as the active layer exhibits a significantly higher adsorption capacity for rare earth ions compared to Comparative Examples 1 and 3-4. Figure 9 It can be seen that the titanium phosphate composite electrode material has a higher capacitance, indicating that the double layer can store a greater number of ions. In Comparative Example 2, activated carbon-titanium phosphate electrode plates were used for direct adsorption without a power supply, and Gd... 3+ The significant decrease in adsorption capacity indicates that the synergistic electrochemical effect of the titanium phosphate composite electrode material can improve the adsorption capacity of rare earth ions.

[0070] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An electrode plate, characterized in that, It includes a conductor layer and an active layer. The active layer includes a titanium phosphate composite electrode material, a conductive agent, and a binder. The titanium phosphate composite electrode material includes a core particle and a shell layer from the inside out. The core particle is a conductive particle, and the shell layer is composed of titanium phosphate nanosheets.

2. The electrode plate according to claim 1, characterized in that, The conductive particles include at least one of activated carbon and carbon nanotubes.

3. The electrode plate according to claim 1, characterized in that, The conductive agent includes conductive carbon black; The adhesive includes at least one of polytetrafluoroethylene, polyimide, and polyvinyl butyral; The conductor layer includes at least one of titanium plate, stainless steel plate, copper plate, and aluminum plate.

4. The electrode plate according to claim 1, characterized in that, The particle size of the titanium phosphate composite electrode material is 10~15μm, and the particle size of the conductive particles is 1~3μm.

5. A method for preparing an electrode plate as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Conductive particles and tetrabutyl titanate are dispersed in anhydrous ethanol, phosphoric acid solution is added, and the mixture is heated and stirred in a water bath. After the reaction is completed, the mixture is filtered and freeze-dried to obtain titanium phosphate composite electrode material. S2. Add the titanium phosphate composite electrode material, conductive agent and binder to the solvent, grind and mix them to obtain an active slurry; S3. The active slurry is coated onto the conductor layer and dried to obtain the electrode plate.

6. The method for preparing the electrode plate according to claim 5, characterized in that, The mass ratio of the conductive particles, tetrabutyl titanate, and phosphoric acid in step S1 is (1~5):(15~20):(60~80).

7. The method for preparing the electrode plate according to claim 5, characterized in that, The water bath heating temperature in step S1 is 40~70℃, and the stirring reaction time is 6~18h.

8. The method for preparing the electrode plate according to claim 5, characterized in that, In step S2, the mass ratio of the titanium phosphate composite electrode material, the conductive agent, and the binder is (8~6):(1~3):

1.

9. The application of an electrode plate as described in any one of claims 1 to 4 in the recovery of low-concentration rare earth ions, characterized in that, Includes the following steps: At least one pair of electrode plates are placed in wastewater containing low concentrations of rare earth ions. Electrolysis is performed after the pair of electrode plates are connected to the positive and negative terminals of a DC power supply. The spacing between a pair of electrode plates is 2~9mm, and the electrolysis voltage is 0.6~1.5V; The electrode plate connected to the positive terminal of the DC power supply is the anode plate, and the electrode plate connected to the negative terminal of the DC power supply is the cathode plate, wherein the rare earth ions are adsorbed on the cathode plate.

10. The application of the electrode plate according to claim 9 in the recovery of low-concentration rare earth ions, characterized in that, After the rare earth ions on the cathode plate reach adsorption equilibrium, the cathode plate is placed in hydrochloric acid solution for desorption.

Images