A targeted defluorination electrode and its preparation method and application

Abstract

The present invention discloses a targeted defluorination electrode, a preparation method thereof and an application thereof, belonging to the technical field of environmental electrochemistry. The preparation method comprises the following steps: using Ti3AlC2 as a raw material, preparing Ti3C2T by a hydrofluoric acid etching method x ; dissolving Ti3C2T x 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; dropping the mixed solution B into the mixed solution A for a polymerization reaction to obtain a polyaldehyde salt / Ti3C2T x material; mixing and grinding the polyaldehyde salt / Ti3C2T x material, a binder and a conductive agent, dissolving with a solvent and coating on a graphite paper substrate, and drying in vacuum to obtain the targeted defluorination electrode. The present invention also discloses the targeted defluorination electrode prepared by the above method and its application. The targeted defluorination electrode of the present invention can solve the problems of poor performance of existing fluoride ion targeted removal and slow defluorination kinetics, and has a wide application prospect.

Description

Technical Field

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

[0002] The problem of groundwater fluoride (F - ) pollution exists worldwide, especially in arid and water-scarce, economically underdeveloped regions. Although fluoride is one of the essential trace elements for the human body, excessive intake can cause serious impacts on human health, such as dental fluorosis, skeletal fluorosis and other diseases, seriously threatening the drinking water safety of residents. Therefore, it is particularly important to develop efficient, economical and environmentally friendly groundwater fluoride pollution control technologies.

[0003] Traditional groundwater fluoride pollution control methods, such as adsorption method, precipitation method, etc., often require the addition of chemical agents, which not only increases the treatment cost, but also may cause secondary pollution, such as the treatment problem of acid-base waste liquid. In addition, these traditional methods also have disadvantages such as long treatment time, slow kinetic process and high equipment maintenance cost, which limit their popularization 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 the directional migration and removal of fluoride ions without adding chemical agents, avoiding the problem of secondary pollution. In the process of electrochemical defluorination, the performance of the electrode material plays a crucial role in the removal efficiency and selectivity of fluoride ions. Therefore, developing high-performance F - targeted removal electrode materials has become 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, a preparation method thereof, and an application thereof, so as to solve the problems of poor performance of existing fluoride ion targeted removal and slow defluorination kinetics.

[0006] To solve the technical problems, the technical solution adopted is to provide a preparation method of a targeted defluorination electrode, including the following steps:

[0007] (1) Using Ti3AlC2 as a raw material, prepare Ti3C2T by hydrofluoric acid etching method x ;

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

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

[0010] (4) Drop the mixed solution B into the mixed solution A for polymerization reaction to obtain polyaldehyde salt / Ti3C2T x material;

[0011] (5) Mix and grind the polyaldehyde salt / Ti3C2T x material, binder and conductive agent, dissolve with a solvent and coat on a graphite paper substrate, and dry in vacuum to obtain the targeted defluorination electrode.

[0012] Preferably, step (1) includes the following steps: fully dissolve Ti3AlC2 in an aqueous hydrofluoric acid solution for stirring reaction, dissolve the solid product after the stirring reaction in water for ultrasonic exfoliation, and freeze-dry to obtain Ti3C2T x .

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

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

[0015] Preferably, the molar concentration of the hydrochloric acid solution in step (2) and step (3) is 0.5 - 2 M; in step (2), the material-liquid ratio of Ti3C2T x , aniline and the hydrochloric acid solution is 1 g:(0.5 - 2) g:(10 - 50) mL; in step (3), the material-liquid ratio of ammonium persulfate and the hydrochloric acid solution 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 1 M; in step (2), the material-liquid ratio of Ti3C2T x , aniline and the hydrochloric acid solution is 1 g:(0.5 - 2) g:30 mL; in step (3), the material-liquid ratio of ammonium persulfate and the hydrochloric acid solution is 0.25 g:20 mL.

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

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

[0019] More preferably, in step (5), the solvent is an N-methylpyrrolidone solution with a purity of 99.5%; the polyaldehyde salt / Ti3C2T x The material-liquid ratio of the material, binder, conductive agent and solvent is 80 mg: 10 mg: 10 mg: 1.5 mL; 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 the application of the above targeted defluorination electrode in targeted removal of fluoride ions in water.

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

[0023] Use a single-chamber capacitive deionization reaction device, with the targeted defluorination electrode serving as both the cathode and the anode, and apply a voltage to remove fluoride ions in the fluoride ion-containing water.

[0024] More preferably, the distance between the cathode and anode plates is 0.4-0.6 cm; the flow rate of the fluoride ion-containing water is 5-30 mL / min; the voltage is 1.0-1.6 V, and the time is 60-420 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 PANI-Cl - with high-selectivity active sites for F x and multi-layer Ti3C2T x with high intercalation capacity for coexisting ions; by regulating the Ti3C2T x layered structure, on the one hand, its intercalation capacity for inorganic ions in groundwater is strengthened, and on the other hand, the specific surface area is increased, providing more binding sites for PANI-Cl x and thus increasing the number of adsorption sites for F - and strengthening the targeted defluorination ability for F - . In addition, under the operating conditions of an applied voltage, the directional migration of inorganic ions further strengthens the selectivity of PANI-Cl x / Ti3C2T x for F - and its intercalation capacity for coexisting ions, realizing the targeted removal of F -The purpose of targeted ultra-fast removal and efficient synchronous removal of co-existing ions. The prepared targeted defluorination electrode of the present invention has strong selectivity for F - It has the advantages of strong selectivity, flexible and simple operation, and no secondary pollution, providing a better solution for the treatment of fluoride-containing groundwater. Brief Description of the Drawings

[0028] Figure 1 XRD patterns of the polyaldehyde salt / Ti3C2T x materials prepared in Examples 1-4 of the present invention;

[0029] Figure 2 It is a graph of the concentration change of fluoride ions treated by the targeted defluorination electrode of the present invention. Detailed Embodiments

[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following examples are used to further elaborate on the present invention. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention, that is, the described examples are only a part of the examples of the present invention, rather than all the examples.

[0031] Therefore, the following detailed description of the provided examples of the present invention is not intended to limit the scope of the claimed invention, but merely represents selected examples of the present invention. All other examples obtained by those skilled in the art based on the examples of the present invention without creative efforts fall within the scope of protection of the present invention.

[0032] The following further describes the characteristics and performance of the present invention in detail with reference to examples. The thickness of the graphite paper substrate is 0.3 mm, 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 for use.

[0033] Example 1

[0034] A preparation method of a targeted defluorination electrode, comprising the following steps:

[0035] (1) Dissolve 1 g of Ti3AlC2 powder in 20 mL of an aqueous hydrofluoric acid solution with a volume concentration of 40%, stir and react at 35 °C in a water bath for 24 h. After the reaction, centrifuge it at a speed of 3500 rpm until the pH value of the supernatant is 6. Then dissolve the obtained solid product in water and perform ultrasonic exfoliation for 30 min. After freeze-drying for 8 h, Ti3C2T x is obtained;

[0036] (2) Dissolve 1 g of Ti3C2T x and 0.5 g of aniline in 30 mL of a hydrochloric acid solution with a molar concentration of 1 M to obtain a mixed solution A;

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

[0038] (4) Drop the mixed solution B into the mixed solution A, carry out a polymerization reaction for 8 h under ice bath conditions, and after vacuum filtration and vacuum drying, obtain a polyaldehyde salt / Ti3C2T x material, denoted as PANI-Cl x / Ti3C2T x -1 electrode material;

[0039] (5) Mix 80 mg of PANI-Cl x / Ti3C2T x -1 electrode material, 10 mg of polyvinylidene fluoride, and 10 mg of acetylene black by grinding, then dissolve them in 1.5 mL of N-methylpyrrolidone solution with a purity of 99.5%, mix and stir for 12 h, and use a spatula to control the coating 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 is obtained, denoted as PANI-Cl x / Ti3C2T x -1 electrode.

[0040] The XRD pattern of the PANI-Cl x / Ti3C2T x -1 electrode material prepared in this example is as Figure 1 shown.

[0041] Example 2

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

[0043] The XRD pattern of the PANI-Cl x / Ti3C2T x -2 electrode material prepared in this example is as Figure 1 shown.

[0044] Example 3

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

[0046] The XRD pattern of the PANI-Cl x / Ti3C2T x -3 electrode material prepared in this example is as Figure 1 shown.

[0047] Example 4

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

[0049] The XRD pattern of the PANI-Cl x / Ti3C2T x -4 electrode material prepared in this example is as Figure 1 shown.

[0050] Example 5

[0051] A preparation method of a targeted defluorination electrode, comprising the following steps:

[0052] (1) Dissolve 1 g of Ti3AlC2 powder completely in 20 mL of an aqueous hydrofluoric acid solution with a volume concentration of 40%, stir and react at 35 °C in a water bath for 24 h. After the reaction is completed, centrifuge it at a rotational speed of 3500 rpm until the pH value of the supernatant is 6. Then dissolve the obtained solid product in water, perform ultrasonic exfoliation for 30 min, and freeze-dry for 8 h to obtain Ti3C2T x ;

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

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

[0055] (4) Drop the mixed solution B into the mixed solution A, carry out the polymerization reaction for 4 h under ice bath conditions, and after vacuum filtration and vacuum drying, obtain the polyaldehyde salt / Ti3C2T x material, denoted as PANI-Cl x / Ti3C2T x -5 electrode material;

[0056] (5) Mix 80 mg of PANI-Cl x / Ti3C2T x -5 electrode material, 10 mg of polyvinylidene fluoride, and 10 mg of acetylene black, grind them and dissolve them in 1.5 mL of N-methylpyrrolidone solution with a purity of 99.5%, mix and stir for 12 h, and use a spatula to control and coat it on the graphite paper substrate with a coating thickness of 200 μm. After vacuum drying at 60 °C for 12 h, the targeted defluorination electrode is obtained, denoted as PANI-Cl x / Ti3C2T x -5 electrode.

[0057] Example 6

[0058] A preparation method of a targeted defluorination electrode, compared with the preparation method of the targeted defluorination electrode in Example 5, is characterized in that: the polymerization reaction time in step (4) is 6 h; the polyaldehyde salt / Ti3C2T x material, denoted as PANI-Cl x / Ti3C2T x -6 electrode material; the targeted defluorination electrode obtained in step (5), denoted as PANI-Cl x / Ti3C2T x -6 electrode; the remaining steps and parameters are the same as those in Example 5.

[0059] Example 7

[0060] A preparation method of a targeted defluorination electrode, compared with the preparation method of the targeted defluorination electrode in Example 5, is characterized in that: the polymerization reaction time in step (4) is 10 h; the polyaldehyde salt / Ti3C2T x material, denoted as PANI-Cl x / Ti3C2T x -7 electrode material; the targeted defluorination electrode obtained in step (5), 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, is characterized in that: the polymerization reaction time in step (4) is 12 h; the polymerized aldehyde salt / Ti3C2T x material, denoted as PANI-Cl x / Ti3C2T x -8 electrode material; the targeted defluorination electrode obtained in step (5), denoted as PANI-Cl x / Ti3C2T x -8 electrode; 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, is characterized in that: the polymerization reaction time in step (4) is 14 h; the polymerized aldehyde salt / Ti3C2T x material, denoted as PANI-Cl x / Ti3C2T x -9 electrode material; the targeted defluorination electrode obtained in step (5), 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 the targeted defluorination electrode on removing fluoride ions from water

[0067] Using a single-chamber capacitive deionization reaction device, the targeted defluorination electrodes prepared in Examples 1-9 were respectively used as the cathode and anode of the single-chamber capacitive deionization reaction device at the same time. The plate spacing was controlled to be 0.5 cm, and a NaF solution with a mass concentration of 50 mg / L was used as the simulated fluoride-containing 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 electrode to conduct a defluorination experiment on the single-chamber capacitive deionization reaction device. A conductivity meter was used to record the change in the solution conductivity. When the conductivity remained unchanged, the electrode reached the electro-adsorption equilibrium. The F - concentration was measured by ion chromatography, and the defluorination capacity and the average defluorination rate were calculated. The calculation formulas for the defluorination capacity and the average defluorination rate are shown in the following formulas (1) and (2) respectively. The defluorination results are shown in Table 1;

[0068] Defluorination capacity:

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

[0070] Wherein, C0 represents the initial concentration of NaF, C t represents the concentration of NaF 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] Wherein, t represents the adsorption equilibrium time.

[0074] Table 1 Defluorination effect of the targeted defluorination electrode

[0075]

[0076] From Figure 1 and the results of Examples 1 - 4 in Table 1, it can be seen that the mass ratio of Ti3C2T x to aniline (ANI) varies within the range of 1:(0.5 - 2), and PANI-Cl x / Ti3C2T x The XRD patterns of the electrode materials can all detect the amorphous diffraction peak of PANI-Cl x and the characteristic peak of Ti3C2T x . Among them, the PANI-Cl x / Ti3C2T x -2 electrode has the best defluorination performance at 1.2V and a relatively fast defluorination rate. From the results of Examples 2, 5 - 9 in Table 1, it can be seen that when the mass ratio of Ti3C2T x to ANI is 1:1 and the polymerization time is 4 - 14h, the prepared targeted defluorination electrode has better effect in removing fluoride ions from water.

[0077] 2. Selectivity analysis of the targeted defluorination electrode for fluoride ions in water

[0078] Using a single-chamber capacitive deionization reaction device, the targeted defluorination electrode of Example 2 (PANI-Cl x / Ti3C2T x -2 electrode) is used as both the cathode and anode of the single-chamber capacitive deionization reaction device, controlling the plate spacing to be 0.5 cm, and using F - and Cl - mixed solution (NaF and NaCl), F - and 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- The mixed solutions (NaF and Na3PO4) were used as simulated fluoride-ion-containing water. The mass concentration of each ion in the above mixed solutions 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 across the electrodes to conduct a competitive-ion experiment on 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 electrodes reached electro-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 Equation (3) below, and 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 co-existing ions, C t represents the concentration of fluoride ions after adsorption equilibrium, and X t represents the concentration of co-existing ions after adsorption equilibrium.

[0082] Table 2 Selectivity analysis of the targeted defluorination electrode for fluoride ions

[0083]

[0084] As can be seen from Table 2, for the PANI-Cl x / Ti3C2T x -2 electrode prepared in Example 2 of the present invention, in different competitive-ion solutions, it can show high selectivity for F - , indicating its targeting for the removal of F - .

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

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

[0087] Table 3 Influence of Voltage on the Defluorination Effect of the Targeted Defluorination Electrode

[0088]

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

[0090] 4. Analysis of the Influence of Fluoride-Ion-Containing Water Flow Rate on the Defluorination Effect in the Application of the Targeted Defluorination Electrode for Targeted Removal of Fluoride Ions in Water

[0091] Using the capacitive deionization reaction device in a single chamber, with the targeted defluorination electrode (PANI-Cl x / Ti3C2T x -2 electrode) prepared in Example 2 simultaneously serving as the cathode and anode of the capacitive deionization reaction device in a single chamber, controlling the plate spacing at 0.5 cm, using a NaF solution with a mass concentration of 50 mg / L as the simulated fluoride-ion-containing water, and controlling the flow rate of the NaF solution by a peristaltic pump at 5, 10, 15, 20, 25, and 30 mL / min. A voltage of 1.2 V is applied on both sides of the electrode to conduct a defluorination experiment on the capacitive deionization reaction device in a single chamber. A conductivity meter is used to record the change in solution conductivity. When the conductivity remains unchanged, the electrode reaches the electroadsorption equilibrium. The F - concentration is determined by ion chromatography, and the defluorination capacity and average defluorination rate are calculated. The results are shown in Table 4.

[0092] Table 4 Influence of Fluoride-Ion-Containing Water Flow Rate on the Defluorination Effect of the Targeted Defluorination Electrode

[0093]

[0094]

[0095] As can be seen from Table 4, for PANI-Cl prepared in Example 2 of the present invention x / Ti3C2T x -2 electrode, during the process of targeted removal of fluoride ions in water, when the flow rate of the fluoride ion-containing water is adjusted within the range of 5 - 30 mL / min, efficient removal of F - can be achieved.

[0096] 5. Application of the targeted defluorination electrode in the targeted removal of fluoride ions in water

[0097] Using a single-chamber capacitive deionization reaction device, with the targeted defluorination electrode (PANI-Cl x / Ti3C2T x -2 electrode) in Example 2 as both the cathode and anode of the single-chamber capacitive deionization reaction device, controlling the plate spacing to be 0.5 cm, using a NaF solution with a mass concentration of 5.0 mg / L as the simulated fluoride ion-containing water, controlling the flow rate of the NaF solution to be 10 mL / min through a peristaltic pump, applying a voltage of 1.2 V on both sides of the electrode, conducting a defluorination experiment on the single-chamber capacitive deionization reaction device, using a conductivity meter to record the change in solution conductivity, and measuring the F - concentration, the results are as Figure 2 shown.

[0098] As can be seen from Figure 2 this, the PANI-Cl x / Ti3C2T x -2 electrode of the present invention exhibits ultra-fast defluorination kinetics, and can reduce the 5.0 mg / L F - solution to 1.5 mg / L (meeting the WHO standard, < 1.5 mg / L) within 90 s, and reduce it to below 1.0 mg / L within 180 s, meeting the requirements of the "Hygienic Standard for Drinking Water" (GB 5749 - 2022), and can effectively reduce the environmental risk of groundwater fluoride pollution.

[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 fall within the scope of the present invention.

Claims

1. A preparation method of a targeted defluorination electrode, characterized in that, It includes the following steps: (1) Prepare Ti3C2Tx using the hydrofluoric acid etching method with Ti3AlC2 as the raw material x ; (2) Dissolve Ti3C2T x and aniline in hydrochloric acid solution to obtain a mixed solution A; (3) Dissolve ammonium persulfate in hydrochloric acid solution to obtain mixed solution B; (4) Add the mixed solution B dropwise to the mixed solution A for polymerization reaction to obtain polyacetal salt / Ti3C2T x material; (5) Mix the polyaldehyde salt / Ti3C2T x material, binder and conductive agent, grind them, dissolve with a solvent and coat on a graphite paper substrate, and then dry in vacuum to obtain the targeted defluorination electrode; The molar concentration of the hydrochloric acid solution in the step (2) and the step (3) is 0.5~2 M; in the step (2), the material ratio of Ti3C2T x , aniline and the hydrochloric acid solution is 1 g:(0.5~2) g:(10~50) mL; in the step (3), the material ratio of ammonium persulfate and the hydrochloric acid solution is 0.25 g:(15~25) mL; In step (5), the binder is polyvinylidene fluoride, the conductive agent is acetylene black, and the solvent is an N-methylpyrrolidone solution with a purity of 99-99.9%; the feed liquid ratio of the polyaldehyde salt / Ti3C2T x material, binder, conductive agent and solvent is (60-100) mg: 10 mg: 10 mg: (1-1.6) mL; the coating thickness is 50-400 μm.

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

3. The preparation method of the target de-fluorination electrode according to claim 2, wherein, The material ratio of Ti3AlC2 to hydrofluoric acid aqueous solution is 1 g:(15 - 25) mL; the volume concentration of the hydrofluoric acid aqueous solution is 35 - 45%; the stirring reaction is carried out under water bath conditions, the temperature is 30 - 40 °C, the time is 22 - 26 h; the ultrasonic stripping time is 25 - 35 min.

4. The preparation method of the targeted defluorination electrode according to claim 1, characterized in that, In step (4), the polymerization reaction is carried out under ice bath conditions for 4 - 14 h.

5. A targeted defluorination electrode prepared by the preparation method according to any one of claims 1 - 4.

6. Use of the targeted defluorination electrode according to claim 5 in targeted removal of fluoride ions in water.

7. The application according to claim 6, characterized in that, It includes the following steps: Use a single-chamber capacitive deionization reaction device, with the targeted defluorination electrode serving as both the cathode and the anode, and apply a voltage to remove fluoride ions in the fluoride ion-containing water.

8. The application according to claim 7, wherein The distance between the cathode and anode plates is 0.4 - 0.6 cm; the flow rate of the fluoride ion-containing water is 5 - 30 mL / min; the voltage is 1.0 - 1.6 V, and the time is 60 - 420 s.

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