Targeted defluorination electrode and preparation method and application thereof

Abstract

The invention discloses a targeted defluorination electrode as well as a preparation method and application thereof, and belongs to the technical field of environmental electrochemistry. The preparation method comprises the following steps: preparing Ti3C2Tx by taking Ti3AlC2 as a raw material and adopting a hydrofluoric acid etching method; the preparation method comprises the following steps: dissolving Ti3C2Tx and aniline in a hydrochloric acid solution to obtain a mixed solution A; dissolving ammonium persulfate in a hydrochloric acid solution to obtain a mixed solution B; dropwise adding the mixed solution B into the mixed solution A, and carrying out polymerization reaction to obtain a polymerized aldehyde salt / Ti < 3 > C < 2 > T < x > material; and mixing and grinding the polymeric aldehyde salt / Ti3C2Tx material, a binder and a conductive agent, dissolving with a solvent, coating on a graphite paper substrate, and carrying out vacuum drying to obtain the targeted defluorination electrode. The invention further discloses the targeted defluorination electrode prepared by the method and application of the targeted defluorination electrode. The targeted defluorination electrode disclosed by the invention can solve the problems that the existing fluorine ion targeted removal performance is poor and the defluorination kinetics is slow, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of environmental electrochemistry, and in particular relates to a targeted defluorination electrode and a preparation method and application thereof. Background Art

[0002] Groundwater fluoride (F - ) Pollution is a common problem in the world, especially in arid, water-scarce and economically underdeveloped areas. Although fluoride is one of the essential trace elements for the human body, excessive intake can have serious effects on human health, such as causing dental fluorosis, skeletal fluorosis and other diseases, which seriously threatens the drinking water safety of residents. Therefore, it is particularly important to develop efficient, economical and environmentally friendly groundwater fluoride pollution control technology.

[0003] Traditional methods for controlling fluoride pollution in groundwater, such as adsorption and precipitation, often require the addition of chemical agents, which not only increases the cost of treatment, but may also cause secondary pollution, such as the treatment of acid and alkali waste liquid. In addition, these traditional methods also have the disadvantages of long treatment time, slow kinetic process and high equipment maintenance cost, which limits their promotion in practical applications.

[0004] As an emerging drinking water treatment technology, electrochemical defluorination technology has attracted much attention due to its advantages such as high efficiency, environmental protection, and easy automation control. Driven by an external electric field, this technology can achieve directional migration and removal of fluoride ions without the addition of chemical agents, thus avoiding the problem of secondary pollution. In the process of electrochemical defluorination, the performance of electrode materials plays a vital role in the removal efficiency and selectivity of fluoride ions. Therefore, the development of high-performance F - Targeted removal of electrode materials becomes the key to improving the efficiency of electrochemical defluorination technology. Summary of the invention

[0005] The problem to be solved by the present invention is to provide a targeted defluorination electrode and a preparation method and application thereof, so as to solve the problems of poor performance of existing fluoride ion targeted removal and slow defluorination kinetics.

[0006] The technical solution adopted to solve the technical problem is to provide a method for preparing a targeted defluorination electrode, comprising the following steps:

[0007] (1) Ti3C2T was prepared by hydrofluoric acid etching using Ti3AlC2 as raw material x ;

[0008] (2) Ti3C2T x Dissolve with aniline in hydrochloric acid solution to obtain mixed solution A;

[0009] (3) dissolving ammonium persulfate in hydrochloric acid solution to obtain a mixed solution B;

[0010] (4) Dropping the mixed solution B into the mixed solution A for polymerization reaction, the polymerized aldehyde salt / Ti3C2T x Material;

[0011] (5) Polyaldehyde salt / Ti3C2T x The material, binder and conductive agent are mixed and ground, dissolved by a solvent and coated on a graphite paper substrate, and then vacuum dried to obtain a targeted defluorination electrode.

[0012] Preferably, step (1) comprises the following steps: fully dissolving Ti3AlC2 in a hydrofluoric acid aqueous solution for stirring reaction, dissolving the solid product after the stirring reaction in water for ultrasonic stripping, and freeze drying to obtain Ti3C2T x .

[0013] More preferably, the material-liquid ratio of Ti3AlC2 and hydrofluoric acid aqueous solution is 1g:(15-25)mL; the volume concentration of hydrofluoric acid aqueous solution is 35-45%; the stirring reaction is carried out in a water bath at a temperature of 30-40°C for 22-26h; and the ultrasonic stripping time is 25-35min.

[0014] More preferably, the material-liquid ratio of Ti3AlC2 and hydrofluoric acid aqueous solution is 1 g:20 mL; the volume concentration of hydrofluoric acid aqueous solution is 40%; the stirring reaction temperature is 35°C and the time is 24 hours; and the ultrasonic stripping time is 30 minutes.

[0015] Preferably, the molar concentration of the hydrochloric acid solution in step (2) and step (3) is 0.5-2M; in step (2), the molar concentration of Ti3C2T x , the material-liquid ratio of aniline to hydrochloric acid solution is 1 g:(0.5-2) g:(10-50) mL; the material-liquid ratio of ammonium persulfate to hydrochloric acid solution in step (3) is 0.25 g:(15-25) mL.

[0016] More preferably, the molar concentration of the hydrochloric acid solution in step (2) and step (3) is 1M; in step (2), the molar concentration of Ti3C2T x , the solid-liquid ratio of aniline and hydrochloric acid solution is 1g:(0.5-2)g:30mL; the solid-liquid ratio of ammonium persulfate and hydrochloric acid solution in step (3) is 0.25g:20mL.

[0017] Preferably, the polymerization reaction in step (4) is carried out under ice bath conditions for 4 to 14 hours.

[0018] Preferably, in step (5), the binder is polyvinylidene fluoride, the conductive agent is acetylene black, and the solvent is N-methylpyrrolidone solution with a purity of 99 to 99.9%; the polymerized aldehyde salt / Ti3C2T xThe material-liquid ratio of the material, the adhesive, the conductive agent and the solvent is (60-100) mg:10 mg:10 mg:(1-1.6) mL; the coating thickness is 50-400 μm.

[0019] More preferably, the solvent in step (5) is a 99.5% pure N-methylpyrrolidone solution; the polymerized aldehyde salt / Ti3C2T x The material-liquid ratio of the material, the binder, the conductive agent and the solvent is 80 mg:10 mg:10 mg:1.5 mL; and the coating thickness is 200 μm.

[0020] The present invention also provides a targeted defluorination electrode prepared by the above preparation method.

[0021] The present invention also provides application of the above-mentioned targeted defluorination electrode in targeted removal of fluoride ions in water.

[0022] Preferably, the use of the targeted defluorination electrode in the targeted removal of fluoride ions in water comprises the following steps:

[0023] A single-chamber capacitive deionization reaction device is used, with a targeted defluorination electrode serving as both a cathode and an anode, and voltage is applied to remove fluoride ions from fluoride-containing water.

[0024] More preferably, the distance between the cathode and anode plates is 0.4 to 0.6 cm; the flow rate of the fluoride-containing water is 5 to 30 mL / min; the voltage is 1.0 to 1.6 V, and the time is 60 to 420 s.

[0025] More preferably, the distance between the cathode and anode plates is 0.5 cm.

[0026] The present invention has the following beneficial effects:

[0027] The targeted defluorination electrode of the present invention is mainly composed of F - PANI-Cl with highly selective active sites x and multilayer Ti3C2T with high intercalation capacity for coexisting ions x Composition; by regulating Ti3C2T x The layered structure not only enhances its intercalation capacity for inorganic ions in groundwater, but also increases the specific surface area. x Provide more binding sites, thereby increasing the affinity for F - The number of adsorption sites of F - In addition, under the operating conditions of applied voltage, the directional migration of inorganic ions further enhances the targeted removal ability of PANI-Cl x / Ti3C2T x F - The selectivity and intercalation capacity of coexisting ions enable F -The targeted ultrafast removal of F and the efficient synchronous removal of coexisting ions are achieved. - The advantages of strong selectivity, flexible and simple operation, and no secondary pollution provide a better solution for the treatment of fluoride-containing groundwater. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The polymerized aldehyde salt / Ti3C2T prepared in Examples 1 to 4 of the present invention x XRD spectrum of the material;

[0029] Figure 2 This is a graph showing the concentration changes of fluoride ions treated by the targeted defluorination electrode of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, that is, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments.

[0031] Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0032] The features and performance of the present invention are further described in detail below in conjunction with the examples. The graphite paper substrate has a thickness of 0.3 mm and is sourced from Hebei Jingtan Technology Co., Ltd. The graphite paper substrates in the following examples are all cut into 2.7 cm×2.7 cm pieces for use.

[0033] Example 1

[0034] A method for preparing a targeted defluorination electrode comprises the following steps:

[0035] (1) 1 g of Ti3AlC2 powder was fully dissolved in 20 mL of a 40% hydrofluoric acid aqueous solution, and the mixture was stirred in a water bath at 35°C for 24 h. After the reaction, the mixture was centrifuged at 3500 rpm until the pH value of the supernatant was 6. The solid product was dissolved in water and subjected to ultrasonic stripping for 30 min. After freeze drying for 8 h, Ti3C2T x ;

[0036] (2) 1g Ti3C2T x 0.5 g of aniline was dissolved in 30 mL of 1 M hydrochloric acid solution to obtain mixed solution A;

[0037] (3) dissolving 0.25 g of ammonium persulfate in 20 mL of 1 M hydrochloric acid solution to obtain a mixed solution B;

[0038] (4) Mixed solution B was added dropwise to mixed solution A, and the polymerization reaction was carried out in an ice bath for 8 h. After vacuum filtration and vacuum drying, the polymerized aldehyde salt / Ti3C2T x Material, denoted as PANI-Cl x / Ti3C2T x -1Electrode materials;

[0039] (5) 80 mg PANI-Cl x / Ti3C2T x -1 electrode material, 10 mg polyvinylidene fluoride and 10 mg acetylene black were mixed and ground, dissolved in 1.5 mL of 99.5% pure N-methylpyrrolidone solution, and stirred for 12 h. The mixture was coated on a graphite paper substrate with a coating thickness of 200 μm. After vacuum drying at 60 ° C for 12 h, the targeted defluorination electrode was obtained, which was denoted as PANI-Cl x / Ti3C2T x -1 electrode.

[0040] PANI-Cl prepared in this example x / Ti3C2T x -1 XRD spectrum of electrode material Figure 1 shown.

[0041] Example 2

[0042] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 1, the difference is that: the amount of aniline added in step (2) is 1g; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -2 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2T x -2 electrodes; the remaining steps and parameters are the same as those in Example 1.

[0043] PANI-Cl prepared in this example x / Ti3C2T x -2 XRD spectrum of electrode material Figure 1 shown.

[0044] Example 3

[0045] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 1, the difference is that: the amount of aniline added in step (2) is 1.5 g; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -3 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2T x -3 electrode; the remaining steps and parameters are the same as those in Example 1.

[0046] PANI-Cl prepared in this example x / Ti3C2T x -3 XRD spectrum of electrode material Figure 1 shown.

[0047] Example 4

[0048] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 1, the difference is that: the amount of aniline added in step (2) is 2g; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -4 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2T x -4 electrodes; the remaining steps and parameters are the same as those in Example 1.

[0049] PANI-Cl prepared in this example x / Ti3C2T x -4 XRD spectrum of electrode material Figure 1 shown.

[0050] Example 5

[0051] A method for preparing a targeted defluorination electrode comprises the following steps:

[0052] (1) 1 g of Ti3AlC2 powder was fully dissolved in 20 mL of a 40% hydrofluoric acid aqueous solution, and the mixture was stirred in a water bath at 35°C for 24 h. After the reaction, the mixture was centrifuged at 3500 rpm until the pH value of the supernatant was 6. The solid product was dissolved in water and subjected to ultrasonic stripping for 30 min. After freeze drying for 8 h, Ti3C2T x ;

[0053] (2) 1g Ti3C2T xDissolve 1g of aniline in 30mL of 1M hydrochloric acid solution to obtain mixed solution A;

[0054] (3) dissolving 0.25 g of ammonium persulfate in 20 mL of 1 M hydrochloric acid solution to obtain a mixed solution B;

[0055] (4) Mixed solution B was added dropwise to mixed solution A, and the polymerization reaction was carried out in an ice bath for 4 h. After vacuum filtration and vacuum drying, the polymerized aldehyde salt / Ti3C2T x Material, denoted as PANI-Cl x / Ti3C2T x -5 electrode materials;

[0056] (5) 80 mg PANI-Cl x / Ti3C2T x -5 electrode material, 10 mg polyvinylidene fluoride and 10 mg acetylene black were mixed and ground, dissolved in 1.5 mL of 99.5% pure N-methylpyrrolidone solution, and stirred for 12 h. The mixture was coated on a graphite paper substrate with a coating thickness of 200 μm. After vacuum drying at 60 ° C for 12 h, the targeted defluorination electrode was obtained, which was denoted as PANI-Cl x / Ti3C2T x -5 electrodes.

[0057] Example 6

[0058] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 5, the difference is that: the polymerization reaction time in step (4) is 6 hours; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -6 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2T x -6 electrodes; the remaining steps and parameters are the same as those in Example 5.

[0059] Example 7

[0060] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 5, the difference is that: the polymerization reaction time in step (4) is 10 hours; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -7 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2Tx -7 electrode; the remaining steps and parameters are the same as those in Example 5.

[0061] Example 8

[0062] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 5, the difference is that: the polymerization reaction time in step (4) is 12 hours; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -8 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2T x -8 electrodes; the remaining steps and parameters are the same as those in Example 5.

[0063] Example 9

[0064] A method for preparing a targeted defluorination electrode, compared with the method for preparing a targeted defluorination electrode in Example 5, the difference is that: the polymerization reaction time in step (4) is 14h; the polymerized aldehyde salt / Ti3C2T obtained in step (4) x Material, denoted as PANI-Cl x / Ti3C2T x -9 electrode material; the targeted defluorination electrode obtained in step (5) is denoted as PANI-Cl x / Ti3C2T x -9 electrode; the remaining steps and parameters are the same as those in Example 5.

[0065] Experimental example

[0066] 1. Analysis of the effect of targeted defluorination electrode in removing fluoride ions from water

[0067] A single-chamber capacitive deionization reaction device was used, and the targeted defluorination electrodes prepared in Examples 1 to 9 were used as the cathode and anode of the single-chamber capacitive deionization reaction device respectively. The plate spacing was controlled to be 0.5 cm. A NaF solution with a mass concentration of 50 mg / L was used as simulated fluoride-containing ion water. The flow rate of the NaF solution was controlled to be 10 mL / min by a peristaltic pump. A voltage of 1.2 V was applied to both sides of the electrode to perform a defluorination experiment of the single-chamber capacitive deionization reaction device. A conductivity meter was used to record the change in solution conductivity. When the conductivity remained unchanged, the electrode reached electrical adsorption equilibrium. F was determined by ion chromatography. - concentration, and calculated the defluorination capacity and average defluorination rate. The calculation formulas of the defluorination capacity and the average defluorination rate are shown in the following equations (1) and (2), respectively. The defluorination results are shown in Table 1.

[0068] Defluorination capacity:

[0069] SAC=(C0-C t )*V / m (1)

[0070] Where C0 represents the initial concentration of NaF, C t represents the NaF concentration after adsorption equilibrium, V represents the volume of the influent NaF solution, and m represents the mass of the electrode material;

[0071] Average defluorination capacity:

[0072] ASAR=SAC / t (2)

[0073] Where t represents the adsorption equilibrium time.

[0074] Table 1 Defluorination effect of targeted defluorination electrode

[0075]

[0076] Depend on Figure 1 As can be seen from the results of Examples 1 to 4 in Table 1, Ti3C2T x The mass ratio of PANI to aniline (ANI) was varied in the range of 1:(0.5-2), and different mass ratios were used to obtain PANI-Cl x / Ti3C2T x The XRD patterns of the electrode materials can detect PANI-Cl x The amorphous diffraction peaks and Ti3C2T x The characteristic peaks of PANI-Cl x / Ti3C2T x -2 electrode has the best defluorination performance at 1.2V and has a faster defluorination rate. It can be seen from the results of Example 2 and Examples 5 to 9 in Table 1 that when Ti3C2T x The targeted defluorination electrode prepared with a mass ratio of ANI to 1:1 and a polymerization time of 4 to 14 hours has a better effect on removing fluoride ions from water.

[0077] 2. Selective analysis of fluoride ions in water by targeted defluorination electrode

[0078] A single-chamber capacitive deionization reaction device was used with the targeted defluorination electrode (PANI-Cl x / Ti3C2T x -2 electrodes) are used as the cathode and anode of the single-chamber capacitive deionization reaction device at the same time, and the distance between the control plates is 0.5 cm. - With Cl - Mixed solution (NaF and NaCl), F - With NO3 - Mixed solution (NaF and NaNO3), F -With CO3 2- Mixed solution (NaF and Na2CO3), F - With SO4 2- Mixed solution (NaF and Na2SO4), F - With PO4 3- A mixed solution (NaF and Na3PO4) was used as simulated fluoride-containing water. The mass concentration of each ion in the mixed solution was 20 mg / L. The flow rate of the solution was controlled at 10 mL / min by a peristaltic pump. A voltage of 1.2 V was applied to both sides of the electrode to conduct a competitive ion experiment of a single-chamber capacitive deionization reaction device. A conductivity meter was used to record the change in solution conductivity. When the conductivity remained unchanged, the electrode reached electrical adsorption equilibrium. The concentration of each ion was determined by ion chromatography, and the fluoride ion selectivity coefficient was calculated. The calculation formula is shown in the following formula (3). The results are shown in Table 2;

[0079] Fluoride ion selectivity coefficient:

[0080]

[0081] In the formula, C0 represents the initial concentration of fluoride ions, X0 represents the initial concentration of coexisting ions, and C t represents the concentration of fluoride ions after adsorption equilibrium, X t Represents the concentration of coexisting ions after adsorption equilibrium.

[0082] Table 2 Selective analysis of targeted defluorination electrodes for fluoride ions

[0083]

[0084] As can be seen from Table 2, for the PANI-Cl prepared in Example 2 of the present invention x / Ti3C2T x -2 electrodes, which can react with F in different competitive ion solutions - It showed high selectivity for F - The removal is targeted.

[0085] 3. Analysis of the influence of voltage on defluorination effect in the application of targeted defluorination electrode in targeted removal of fluoride ions from water

[0086] A single-chamber capacitive deionization reaction device was used with the targeted defluorination electrode (PANI-Cl x / Ti3C2T x-2 electrodes) were used as cathode and anode of a single-chamber capacitive deionization reaction device at the same time, the plate spacing was controlled to be 0.5 cm, a NaF solution with a mass concentration of 50 mg / L was used as simulated fluoride-containing ion water, the flow rate of the NaF solution was controlled to be 10 mL / min by a peristaltic pump, voltages of 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, and 1.6 V were applied on both sides of the electrodes, and a defluorination experiment of a single-chamber capacitive deionization reaction device was carried out. A conductivity meter was used to record the change in solution conductivity. When the conductivity remained unchanged, the electrodes reached electrical adsorption equilibrium, and F was determined by ion chromatography. - The concentration was measured and the defluorination capacity and average defluorination rate were calculated. The results are shown in Table 3.

[0087] Table 3 Effect of voltage on the defluorination effect of targeted defluorination electrode

[0088]

[0089] As can be seen from Table 3, for the PANI-Cl prepared in Example 2 of the present invention x / Ti3C2T x In the process of targeted removal of fluoride ions from water, the applied voltage of the -2 electrode can be adjusted in the range of 1.0 to 1.6 V, and both can achieve F - Efficient removal.

[0090] 4. Application of targeted defluorination electrode in targeted removal of fluoride ions from water Analysis of the influence of fluoride ion water flow rate on defluorination effect

[0091] A single-chamber capacitive deionization reaction device was used with the targeted defluorination electrode (PANI-Cl x / Ti3C2T x -2 electrodes) were used as cathode and anode of a single-chamber capacitive deionization reaction device at the same time, the plate spacing was controlled to be 0.5 cm, a NaF solution with a mass concentration of 50 mg / L was used as simulated fluoride-containing ion water, the flow rate of the NaF solution was controlled by a peristaltic pump to be 5, 10, 15, 20, 25, and 30 mL / min, a voltage of 1.2 V was applied to both sides of the electrodes, and a defluorination experiment of a single-chamber capacitive deionization reaction device was carried out. A conductivity meter was used to record the change in solution conductivity. When the conductivity remained unchanged, the electrodes reached electrical adsorption equilibrium, and F was determined by ion chromatography. - The concentration was measured and the defluorination capacity and average defluorination rate were calculated. The results are shown in Table 4.

[0092] Table 4 Effect of fluoride ion water flow rate on the defluorination effect of targeted defluorination electrode

[0093]

[0094]

[0095] It can be seen from Table 4 that for the PANI-Cl prepared in Example 2 of the present invention x / Ti3C2T x In the process of targeted removal of fluoride ions from water, the flow rate of fluoride-containing water can be adjusted within the range of 5 to 30 mL / min. - Efficient removal.

[0096] 5. Application of targeted defluorination electrodes in targeted removal of fluoride ions from water

[0097] A single-chamber capacitive deionization reaction device was used with the targeted defluorination electrode (PANI-Cl x / Ti3C2T x -2 electrodes) were used as the cathode and anode of a single-chamber capacitive deionization reaction device at the same time, the plate spacing was controlled to be 0.5 cm, a NaF solution with a mass concentration of 5.0 mg / L was used as simulated fluoride-containing ion water, the flow rate of the NaF solution was controlled to be 10 mL / min by a peristaltic pump, a voltage of 1.2 V was applied on both sides of the electrodes, and a defluorination experiment of a single-chamber capacitive deionization reaction device was carried out. A conductivity meter was used to record the change in solution conductivity, and F was determined by ion chromatography. - Concentration, the results are as follows Figure 2 shown.

[0098] from Figure 2 It can be seen that the PANI-Cl x / Ti3C2T x The -2 electrode exhibits ultrafast defluorination kinetics, converting 5.0 mg / L F - The solution concentration is reduced to 1.5 mg / L (meets the WHO standard, <1.5 mg / L), and is reduced to below 1.0 mg / L within 180 seconds, meeting the requirements of the "Quality Standard for Drinking Water" (GB 5749-2022), which can effectively reduce the environmental risk of fluoride pollution in groundwater.

[0099] The present invention has been described according to the above embodiments. It should be understood that the above embodiments do not limit the present invention in any form. Any technical solutions obtained by equivalent replacement or equivalent transformation shall fall within the scope of the present invention.

Claims

1. A method for preparing a targeted defluorination electrode, characterized in that: The following steps are involved: (1) Ti3C2T was prepared by hydrofluoric acid etching using Ti3AlC2 as raw material x ; (2) Ti3C2T x Dissolve with aniline in hydrochloric acid solution to obtain mixed solution A; (3) dissolving ammonium persulfate in hydrochloric acid solution to obtain a mixed solution B; (4) Dropping the mixed solution B into the mixed solution A for polymerization reaction, the polymerized aldehyde salt / Ti3C2T x Material; (5) Polyaldehyde salt / Ti3C2T x The material, binder and conductive agent are mixed and ground, dissolved in a solvent and coated on a graphite paper substrate, and then vacuum dried to obtain a targeted defluorination electrode.

2. The method for preparing a targeted defluorination electrode according to claim 1, characterized in that: The step (1) comprises the following steps: fully dissolving Ti3AlC2 in a hydrofluoric acid aqueous solution for stirring reaction, dissolving the solid product after the stirring reaction in water for ultrasonic stripping, and freeze drying to obtain Ti3C2T x .

3. The method for preparing the targeted defluorination electrode according to claim 2, characterized in that: The material-liquid ratio of the Ti3AlC2 and the hydrofluoric acid aqueous solution is 1g:(15-25)mL; the volume concentration of the hydrofluoric acid aqueous solution is 35-45%; the stirring reaction is carried out in a water bath at a temperature of 30-40°C for 22-26h; and the ultrasonic stripping time is 25-35min.

4. The method for preparing a targeted defluorination electrode according to claim 1, characterized in that: The molar concentration of the hydrochloric acid solution in step (2) and step (3) is 0.5-2M; the molar concentration of Ti3C2T x , the material-liquid ratio of aniline to hydrochloric acid solution is 1 g: (0.5-2) g: (10-50) mL; in the step (3), the material-liquid ratio of ammonium persulfate to hydrochloric acid solution is 0.25 g: (15-25) mL.

5. The method for preparing a targeted defluorination electrode according to claim 1, characterized in that: The polymerization reaction in step (4) is carried out in an ice bath for 4 to 14 hours.

6. The method for preparing a targeted defluorination electrode according to claim 1, characterized in that: In the step (5), the binder is polyvinylidene fluoride, the conductive agent is acetylene black, and the solvent is N-methylpyrrolidone solution with a purity of 99-99.9%; the polymerized aldehyde salt / Ti3C2T x The material-liquid ratio of the material, the binder, the conductive agent and the solvent is (60-100) mg:10 mg:10 mg:(1-1.6) mL; the coating thickness is 50-400 μm.

7. A targeted defluorination electrode prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the targeted defluorination electrode according to claim 7 in the targeted removal of fluoride ions in water.

9. The use according to claim 8, characterized in that The following steps are involved: A single-chamber capacitive deionization reaction device is used, with a targeted defluorination electrode serving as both a cathode and an anode, and voltage is applied to remove fluoride ions from fluoride-containing water.

10. The use according to claim 9, characterized in that The distance between the cathode and anode plates is 0.4 to 0.6 cm; the flow rate of the fluoride ion water is 5 to 30 mL / min; the voltage is 1.0 to 1.6 V, and the time is 60 to 420 s.

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