Ag-based cd i active material and its preparation and use in cd i

Abstract

The application belongs to the field of wastewater treatment, and particularly relates to an Ag-based CDI active material, which comprises an Ag-modifier framework material and Ag nanoclusters dispersedly distributed in the framework material; the modifier is at least one organic matter with a HOOC-Ar-COOH structure. The application also provides a preparation method for the Ag-based CDI active material by using an Ag source and a modifier for pre-reaction under ultrasonic and solvent thermal reaction, and application of the Ag-based CDI active material in CDI. The Ag-based CDI active material has excellent CDI adsorption capacity and stability.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, specifically relating to materials for electrochemical deionization wastewater treatment. Background Technology

[0002] Contains Cl - Efficient wastewater purification has become an urgent technical challenge for the metallurgical industry and the environmental protection sector. Industries such as metallurgy generate large quantities of high-concentration chlorine-containing wastewater, which, if not properly treated, can lead to corrosion of industrial equipment and endanger ecological and environmental safety.

[0003] The currently widely used membrane separation + evaporation crystallization process often results in the formation of mixed salts, making resource utilization difficult and forcing them into stockpiling, thus posing a significant environmental pollution hazard. Therefore, it is essential to remove Cl from the process. - Selective separation avoids salt mixing and facilitates resource recovery. Typically, Cl... - Able to work with Ag + Cu + and Bi 3+ Plasma interactions produce precipitates, thus achieving selective precipitation separation. However, this often requires the addition of excessive precipitating agents, leading to a significant increase in costs and secondary pollution problems.

[0004] The Ag electrode based on the Faraday reaction is used for high-salinity wastewater Cl. - Selective separation provides a feasible approach. Utilizing Ag and Cl... - The specific binding reaction of Cl-, controlled by factors such as solution potential, theoretically allows the Ag electrode to achieve highly selective electrochemical capture of Cl-. - .

[0005] For example, Chinese patent document CN115463625A discloses a silver nanowire-lignin-derived carbon composite aerogel. Another example is Chinese patent document CN113257586A. Chinese patent document CN108883952A discloses a silver-based electrode for capacitor deionization.

[0006] In summary, although some silver-based CDI electrode materials have been reported in existing technologies, the poor electrochemical field cycling stability of traditional Ag / C electrodes remains a technical bottleneck for their electrochemical selective dechlorination. Under the action of an electric field, Ag and Cl... - The formation of AgCl leads to severe volume expansion of Ag nanoparticles (expansion rate can reach 225%), causing intergranular cracks, pulverization, and loss in Ag / C materials, severely affecting the material's cycling stability. Therefore, it is urgent to develop new research strategies to solve the stability problem of Ag electrodes and achieve the resource-based treatment of chlorine-containing wastewater. Summary of the Invention

[0007] In view of the deficiencies in the prior art, the first object of the present application is to provide an Ag-based CDI active material, aiming to provide a CDI active material with excellent CDI treatment capacity and cycle stability.

[0008] The second object of the present application is to provide a preparation method of the Ag-based CDI active material and its application in CDI electric adsorption.

[0009] The third object of the present application is to provide a CDI electrode containing the Ag-based CDI active material and its application in wastewater treatment.

[0010] The existing Ag-based CDI adsorption capacity and stability are not ideal, and in view of this problem, the present application provides the following improvement scheme:

[0011] An Ag-based CDI active material, comprising an Ag-modifier framework material, and Ag nanoclusters dispersedly distributed therein;

[0012] The modifier is at least one organic compound with the structure of formula 1;

[0013] HOOC-Ar-COOH

[0014] Formula 1;

[0015] The Ar is a single aromatic ring, or a polycyclic structure with two or more aromatic rings formed by parallel connection or based on conjugated bond connection of a single aromatic ring, and in formula 1, the two -COOH are in the para position of Ar.

[0016] The present application provides a brand new Ag-based CDI active material, and the Ag-based CDI active material can unexpectedly exhibit excellent CDI adsorption activity and excellent cycle stability in the field of CDI.

[0017] In the present application, the modifier is at least one compound with the following structural formula;

[0018]

[0019] X1, X2 are independently C or N; R1 is at least one of H, amino, alkylamino, hydroxyl, halogen, alkoxy, trifluoromethyl;

[0020] The Ag nanoclusters dispersedly distributed therein are formed in situ and have mixed valence (Ag + / Ag 0 ), and the particle size of the cluster is 2.1-4.9 nm.

[0021] In the present application, an exemplary modifier can be at least one compound with the following structure;

[0022]

[0023] The application also provides a preparation method of the Ag-based CDI active material, wherein a silver source and a modifier are pre-reacted under ultrasonic assistance, and then a solvothermal reaction is performed.

[0024] The application innovatively pre-reacts a silver source and a modifier under ultrasonic assistance, and then performs a solvothermal reaction, so that a synergistic effect can be unexpectedly achieved, and an Ag-modifier framework material with dispersed Ag nanoclusters can be formed, and the material prepared by the preparation method can solve the problems of the Ag-based CDI material, and can unexpectedly significantly improve the CDI adsorption capacity and stability.

[0025] In the application, the silver source includes a soluble Ag-containing compound, and is preferably at least one of silver acetate, silver nitrate, silver citrate, silver trifluoroacetate, silver phosphate, silver acetylacetone, and silver tetrafluoroborate.

[0026] In the application, the molar ratio of the silver source to the modifier is 1:1-4, and is preferably 1:1-2.

[0027] In the application, the solvent in the pre-reaction stage is not particularly limited, and for example, can be at least one of an alcohol, DMF, deionized water, a mixture of deionized water and an alcohol, and a mixture of deionized water and DMF.

[0028] In the application, the ultrasonic power in the pre-reaction stage is not particularly limited, and for example, can be 150-200 W. The temperature in the treatment process can be controlled to be 50-80 DEG C.

[0029] In the application, the pre-reaction time is more than 0.3 h, and considering the preparation efficiency, the pre-reaction time can be further 0.5-1.5 h, and more further 0.5-1 h.

[0030] In the application, the pre-reaction system can be directly subjected to a solvothermal reaction in a pressure-resistant container.

[0031] In the application, the temperature in the solvothermal reaction is more than 100 DEG C, and is preferably 120-150 DEG C.

[0032] In the application, the time in the solvothermal reaction is more than 1 h, and is further 2-5 h.

[0033] After the solvothermal reaction, the product can be obtained based on a conventional solid-liquid separation such as centrifugation, and in addition, the product can be cleaned as required, and the cleaning step can include steps of cleaning with DMF, ethanol, deionized water, and the like.

[0034] The application further provides an application of the Ag-based CDI active material as an active material for CDI adsorption of anions.

[0035] In the application, the Ag-based CDI active material can be used as an active material for CDI adsorption based on a conventional CDI treatment method.

[0036] In the application, the Ag-based CDI active material is used as an active material for CDI adsorption of anions from wastewater containing anions.

[0037] In the application, the anions include chloride ions.

[0038] The application further provides a CDI electrode comprising a current collector and a CDI electrode material compounded on the surface of the current collector, wherein the CDI electrode material comprises an active material, a binder and a conductive agent, and the active material comprises the Ag-based CDI active material.

[0039] In the application, the content of the Ag-based CDI active material in the active material is more than 50 wt.%.

[0040] In the application, the current collector can be a current collector known in the industry, and further can be carbon paper, graphite paper, carbon cloth or a titanium plate.

[0041] In the application, the conductive agent is at least one of acetylene black and conductive carbon black.

[0042] In the application, the binder is at least one of PVDF and PTFE.

[0043] In the application, the weight ratio of the active material, the binder and the conductive agent in the active material is 75-99:1-15:1-15, and further can be 75-85:5-15:5-15.

[0044] The electrode can be prepared based on a conventional slurry coating method.

[0045] The application further provides a CDI device comprising the Ag-based CDI active material.

[0046] The CDI device comprises the Ag-based CDI active material, and other components and parts can be conventional.

[0047] Advantages

[0048] 1. The application provides a brand-new idea for solving the stability of Ag electrode, and provides a brand-new Ag-based CDI active material, which is based on the combination of Ag-modifier framework material and Ag nanocluster dispersion structure, can unexpectedly realize synergy, can strengthen the interface stability of Ag electrode, and can improve Ag utilization rate, adsorption performance such as adsorption capacity and stability.

[0049] For example, the active material provided by the application exhibits high Cl - The active material provided by the application has excellent electric adsorption performance, high Ag utilization rate and excellent cyclic use performance, and still retains 96.93% of the performance after 100 cycles, which is better than most Ag-based electrode materials at present, and when used as a CDI electrode, in a 500mg / L NaCl solution, under a current density of 20mA / g, the Cl - adsorption capacity is 121.52mg / g, and the utilization rate of active Ag is 60.54%.

[0050] 2. The application also innovatively provides an ultrasonic-assisted pre-reaction and solvothermal preparation idea of Ag source and modifier, and the preparation method can construct an Ag-modifier framework and nanosilver cluster dispersion structure that meet the requirements of CDI, and can improve the capacity and stability of the prepared CDI. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The XRD diagram of the AgNC@AgPM and AgNC materials prepared for Example 1 and Comparative Example 1; in the diagram, AgNC@AgPM refers to the product after treatment of Example 1, and AgNC refers to the product after treatment of Comparative Example 1.

[0052] Figure 2 The AgNC@AgPM structure identification diagram of the material prepared for Example 1, wherein, Figure 2 a is the SEM diagram of the AgNC@AgPM prepared for Example 1, Figure 2 b-2d is the SEM diagram of the AgNC@AgPM prepared for Example 1, Figure 2 the histogram in the inset of c is the particle size distribution histogram of the Ag nanocluster in the AgNC@AgPM prepared for Example 1, Figure 2 the inset in d is the lattice fringe of the Ag nanocluster in the AgNC@AgPM prepared for Example 1.

[0053] Figure 3 The TEM diagram of the material prepared for Comparative Example 2.

[0054] Figure 4 The TEM diagram of the material prepared for Comparative Example 3.

[0055] Figure 5The graph shows the test results for Experiment 2, where... Figure 5 Cyclic voltammetry curves of AgNC@AgPM prepared in Example 1 at different scan rates in 1M NaCl solution. Figure 5 b shows the cyclic voltammetry curves of AgNC prepared in Comparative Example 1 at different scan rates in 1M NaCl solution. Figure 5 c represents the electrochemical specific capacitance of AgNC@AgPM prepared in Example 1 and AgNC prepared in Comparative Example 1; in the figure, AgNC@AgPM refers to the product after treatment in Example 1, and AgNC refers to the product after treatment in Comparative Example 1.

[0056] Figure 6 The graph shows the test results of Experiment 3, where... Figure 6 a represents the cyclic voltammetry curve of the CDI unit assembled using AgNC@AgPM as the anode and AC as the cathode, prepared in Example 1. Figure 6 b represents the cyclic voltammetry curves of the CDI unit assembled with AC as the anode and cathode, respectively; in the figure, AgNC@AgPM refers to the product after treatment in Example 1, and AC refers to commercially purchased activated carbon.

[0057] Figure 7 The graph shows the test results for Experiment 4. Figure 7 a represents AgNC@AgPM prepared in Example 1, and the electro-adsorption dechlorination performance of AgNC prepared in Comparative Example 1 and commercially available Ag powder is compared. Figure 7 b represents the dechlorination rate of AgNC@AgPM prepared in Example 1 at different current densities. Figure 7 c represents the Ag utilization rate of AgNC@AgPM prepared in Example 1, AgNC prepared in Comparative Example 1, and commercially available Ag powder; in the figure, AgNC@AgPM refers to the product after treatment in Example 1, AgNC refers to the product after treatment in Comparative Example 1, and Bulk Ag is commercially available Ag powder.

[0058] Figure 8 The electroadsorption dechlorination cycle performance of AgNC@AgPM prepared in Example 1, AgNC prepared in Comparative Example 1, and commercially available Ag powder is shown in the figure. In the figure, AgNC@AgPM refers to the product after treatment in Example 1, AgNC refers to the product after treatment in Comparative Example 1, and BulkAg is commercially available Ag powder.

[0059] In the figures above, AgNC@AgPM represents the Ag-based CDI active material of this invention; BulkAg represents commercially available Ag powder (Shanghai Aladdin Biochemical Technology Co., Ltd., 99.9% metal content, 1 μm particle size); AC represents commercially available activated carbon (Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., specific surface area 1800 m²). 2 / g). Detailed Implementation

[0060] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort are within the protection scope of the present application.

[0061] The technical solutions among the various embodiments of the present application can be combined with each other, but it must be based on that a person of ordinary skill in the art can realize. When the combination of the technical solutions appears contradictory or unachievable, it should be considered that the combination of the technical solutions does not exist, and is not within the protection scope of the present application.

[0062] It should be known by a person of ordinary skill in the art that, as the description of the drawings of the present application, the intensity in the drawings of the present application can be understood as intensity, and the cycle number can be understood as cycle number, without affecting the understanding of the present application.

[0063] In order to have a further understanding of the present application, examples are given as follows:

[0064] Embodiment 1

[0065] The preparation method of the new type of chlorine ion removal material Ag-based CDI active material based on Faraday conversion mechanism in the present embodiment includes the following steps:

[0066] (1) 84.94 mg (0.5 mmol) of silver nitrate was weighed and dissolved in 60 mL of anhydrous ethanol solution to obtain solution one;

[0067] (2) 90.58 mg (0.5 mmol) of formula A (modifier) was weighed and dissolved in 5 mL of DMF to obtain solution two, and then the DMF containing formula A was slowly added to solution one using a syringe pump, followed by ultrasonic (150-200 W) pre-reaction for 30 min (the temperature of the treatment process was 60-75 ℃), to obtain mixed solution three;

[0068] (3) The mixed solution three was transferred to a polytetrafluoroethylene stainless steel reaction kettle, and heated at 120 ℃ (solvothermal temperature T) for 2 h (solvothermal time), to obtain mixed solution four;

[0069] (4) After the reaction kettle was cooled to room temperature, the obtained mixed solution four was centrifuged, and washed several times with DMF, anhydrous ethanol and deionized water, and then dried at 60 ℃ under vacuum for 6 h to obtain the Ag-based CDI active material (also referred to as AgNC@AgPM).

[0070] Embodiment 2

[0071] The difference between Example 1 and Comparative Example 1 is that the kind of modifier is changed. The other parameters are the same as those in Example 1. The experimental groups are as follows:

[0072] Group A: the modifier is Formula B;

[0073] Group B: the modifier is Formula C;

[0074] Group C: the modifier is Formula D;

[0075] Group D: the modifier is Formula E.

[0076] The other operations and parameters are the same as those in Example 1. Similar materials to those in Example 1 can be obtained.

[0077] Example 3

[0078] The difference between Example 1 and Example 3 is that the amount of the modifier is changed, and the molar ratio of silver nitrate to the modifier is 1:2. The other operations and parameters are the same as those in Example 1. It is found through testing that similar materials to those in Example 1 can be obtained.

[0079] Example 4

[0080] The difference between Example 1 and Example 4 is that the solvothermal temperature T is changed to 130°C. The other operations and parameters are the same as those in Example 1. It is found through testing that similar materials to those in Example 1 can be obtained.

[0081] Example 5

[0082] The difference between Example 1 and Example 5 is that the holding time at the solvothermal temperature is changed to 5h. The other operations and parameters are the same as those in Example 1. It is found through testing that similar materials to those in Example 1 can be obtained.

[0083] Comparative Example 1

[0084] The difference between Example 1 and Comparative Example 1 is that the Ag-based CDI active material prepared in Step 4 is placed in a quartz tube furnace and heated to 800°C at a heating rate of 5°C / min in a nitrogen atmosphere, and then the system is naturally cooled to room temperature. The sample obtained in this way is AgNC. The main component of AgNC is metallic Ag, and the Ag content is 83.15%.

[0085] Comparative Example 2

[0086] The difference between Example 1 and Comparative Example 2 is that the modifier in Step 2 is changed to an asymmetric carboxyl structure (specifically, benzoic acid). The other operations and parameters are the same as those in Example 1.

[0087] The SEM of the material prepared is shown in Figure 3 As shown in Figure 3 , dispersed nano-Ag clusters cannot be obtained.

[0088] Comparative Example 3

[0089] Comparative Example 3 is the same as Example 1 except that the ultrasonic treatment in Step 2 is not used, but instead the stirring is directly carried out at the same temperature for 1 h, and then the subsequent operations are carried out, and the other operations and parameters are the same as in Example 1.

[0090] The SEM of the material prepared is shown in Figure 4 As shown in Figure 4 , no dispersed nano-Ag clusters can be obtained.

[0091] <Experiment>

[0092] The following experiments were carried out on the product of Example 1 above.

[0093] <Experiment 1>

[0094] The purpose of this experiment is to characterize the crystal structure and morphology of the Ag-based CDI active material powder synthesized.

[0095] As shown in Figure 1 , the XRD diffraction peaks of the AgNC@AgPM powder prepared according to the final step (4) of Example 1 above are at 6.33°, 12.68°, 15.32°, 17.97°, 19.09°, 22.03°, 24.34°, 25.19°, 26.59°, 30.38°, 32.85°, 38.15°, 40.30°, 44.26°, 46.23°, 64.59°, 77.35°, in addition, the diffraction peaks of the AgNC@AgPM powder are at 38.14°, 44.24°, 64.48° and 77.38°, which respectively correspond to the (111), (200), (220) and (311) diffraction peaks in the standard card of Ag with a body-centered cubic structure, indicating that Ag element exists in the AgNC@AgPM sample; while the AgNC material prepared in Comparative Example 1 only contains the peaks of metallic Ag, which are completely consistent with the standard peaks in the standard card of Ag PDF #04-004-6434.

[0096] As shown in Figure 2 , the SEM of the AgNC@AgPM powder prepared according to the final step (4) of Example 1 above is shown in Figure 2 a) The test shows that the AgNC@AgPM has a smooth surface and a nanorod morphology; the TEM of the AgNC@AgPM powder is shown in Figure 2 b-2c) The test shows that the nano-Ag clusters are uniformly dispersed inside the AgNC@AgPM, and the average particle size of the Ag clusters is 3.49 nm, Figure 2The lattice fringes in d are the (020) crystal plane of metallic Ag, indicating that metallic Ag also exists in AgNC@AgPM.

[0097] <Experiment 2>

[0098] The purpose of this experiment was to investigate the electrochemical performance of a novel chloride ion removal Ag-based CDI active material (Example 1 being a typical example). The specific procedure was as follows: 8 mg of Example 1, Comparative Example 1, commercial Ag powder, and the Ag-based CDI active material prepared in Example 1, along with 1 mg of conductive carbon black and 1 mg of PVDF as a binder, were mixed and dissolved in 0.6 mL of NMP. The mixture was then ultrasonically treated and stirred for 30 minutes to form a homogeneous slurry. 50 μL of this slurry was then coated onto a 1×1 cm... 2 Carbon paper was vacuum dried overnight at 120°C. The prepared electrode was placed in a 1 mol / L NaCl electrolyte, with a platinum electrode as the counter electrode and silver / silver chloride as the reference electrode, and electrochemical tests were performed using a three-electrode method.

[0099] Cyclic voltammetry curves of the Ag-based CDI active material obtained in Example 1 were measured at scan rates of 1-50 mV / s. Figure 5 a) The AgNC@AgPM electrode showed symmetrical redox peaks at scan rates ranging from 1 to 50 mV / s. AgNC also showed similar results. Figure 5 b). The CV curves of each electrode show a distinct oxidation peak at 0.12 V and a distinct reduction peak at -0.05 V (relative to Ag / AgCl), which is related to the reversible electrochemical conversion between Ag and AgCl. At scan rates of 1-50 mV / s, AgNC@AgPM exhibits the highest specific capacitance. Figure 5 c).

[0100] Experiment 3

[0101] The purpose of this experiment is to investigate the electrochemical performance of a novel chloride ion removal Ag-based CDI active material (exemplified by Example 1) on an asymmetric CDI device.

[0102] The organic linker-coordinated Ag structure electrode prepared in Example 1 above was processed using the capacitive deionization electrode preparation method described above: 80 wt% of the active material, 10 wt% of acetylene black, and 10 wt% of PVDF were dissolved in 1 mL of NMP, then ultrasonicated and stirred for 30 minutes to form a homogeneous slurry. 1 mL of the mixed slurry was coated onto a current collector and dried overnight at 120°C. The resulting CDI electrode was assembled into a CDI unit, and the salt solution to be treated was delivered to the CDI unit using a peristaltic pump. Testing was performed using an electrochemical workstation. Figure 6The CDI cell assembled with the organic linker coordinated Ag structure electrode prepared in Example 1 as an anode and AC as a cathode showed obvious redox effect, and the CV curve of the CDI device using AC as an anode and a cathode showed a rectangular shape, indicating that the storage of ions mainly relied on the double-layer effect.

[0103] <Experiment 4>

[0104] The purpose of this experiment is to explore the dechlorination performance and dechlorination rate of the new chlorine ion removal Ag-based CDI active material (typical listed in Example 1).

[0105] The electrode was prepared by using Bulk Ag, AgNC or the Ag-based CDI active material obtained in Example 1 as the active material, and the steps were as follows: 80wt% of the active material, 10wt% of acetylene black and 10wt% of PVDF were dissolved in 1mL of NMP, then ultrasonic treatment and stirring for 30 minutes were performed to form a uniform slurry. 1mL of the mixed slurry was coated on the current collector, and dried at 120°C overnight. The obtained CDI electrode was assembled into a CDI cell, a certain external current was applied between the positive and negative electrodes, and the salt solution to be treated was delivered into the CDI cell by a peristaltic pump to test the electrochemical performance of the CDI device. As shown in Figure 7 a, the Ag-based CDI active material showed the optimal Cl - removal capacity. Under the condition of 20mA / g current density and 500mg / L NaCl, the Cl - removal capacity of the Ag-based CDI active material was 121.52mg Cl / g Anode , and the corresponding dechlorination rate was 0.43mg Cl / g Anode / min. Under the condition of 30mA / g current density and 500mg / L NaCl, the Cl - removal capacity of the Ag-based CDI active material was 109.64mg Cl / g Anode , and the corresponding dechlorination rate was 0.80mg Cl / g Anode / min. Under the condition of 50mA / g current density and 500mg / L NaCl, the Cl - removal capacity of the Ag-based CDI active material was 94.11mg Cl / g Anode , and the corresponding dechlorination rate was 1.32mg Cl / g Anode / min. Under the condition of 100mA / g current density and 500mg / L NaCl, the Cl -The removal capacity is 78.11 mg Cl / g Anode The corresponding dechlorination rate is 2.60 mg Cl / g Anode / min; the Ag utilization rates of the Ag-based CDI active material, Bulk Ag and AgNC are 60.54%, 24.74% and 32.64% respectively Figure 7 c).

[0106] <Experiment 5>

[0107] The purpose of this experiment is to explore the cycle stability of the new Ag-based CDI active material for removing chloride ions.

[0108] The electrode is prepared by using the Bulk Ag, AgNC or Ag-based CDI active material as the active material, that is, 80wt% of the active material, 10wt% of acetylene black and 10wt% of PVDF are dissolved in 1mL of NMP, then ultrasonic treatment and stirring for 30 minutes are performed to form a uniform slurry. 1mL of the mixed slurry is coated on the current collector, and dried at 120°C overnight. The obtained CDI electrode is assembled into a CDI unit, a certain external current is applied between the positive and negative electrodes, the salt solution to be treated is delivered into the CDI unit by a peristaltic pump, and the electrochemical performance test of the CDI device is performed. As shown in Table 2, the capacity retention rates of the Bulk Ag, AgNC and AgNC@AgPM are 40.26%, 76.92% and 96.96% respectively after 100 cycles in a 50mA / g, 500mg / L NaCl solution, the AgNC@AgPM exhibits ultra-high cycle performance, which confirms that the organic linker coordinated Ag structure has a great effect on stabilizing the Ag electrode. Figure 8

[0109] <Experiment 6>

[0110] According to Experiment 4, the CDI performance test is performed on the materials prepared by changing the types of modifiers in Example 2, and the results are as follows:

[0111] Group A: under the condition of 30mA / g current density and 500mg / L NaCl, the Cl - removal capacity is 113.51 mg Cl / g Anode , and the retention rate after 100 cycles is 93.23%.

[0112] Group B: under the condition of 30mA / g current density and 500mg / L NaCl, the Cl - removal capacity is 99.32 mg Cl / g Anode , and the retention rate after 100 cycles is 95.23%. ​

[0113] Group C: under the condition of 30 mA / g current density and 500 mg / L NaCl, Cl - The removal capacity was 126.36 mg / g Cl / g Anode The retention rate after 100 cycles was 98.23%.

[0114] Group D: under the condition of 30 mA / g current density and 500 mg / L NaCl, Cl - The removal capacity was 137.25 mg / g Cl / g Anode The retention rate after 100 cycles was 99.36%.

[0115] In Experiment 6, the test conditions and results are shown in Table 1:

[0116] Table 1

[0117]

[0118] <Experiment 7>

[0119] According to Experiment 4, the material in Comparative Example 2 was tested for CDI performance under the condition of 30 mA / g current density and 500 mg / L NaCl, Cl - The removal capacity was 8.13 mg / g Cl / g Anode The retention rate after 100 cycles was 10%.

[0120] <Experiment 8>

[0121] According to Experiment 4, the material in Comparative Example 3 was tested for CDI performance under the condition of 30 mA / g current density and 500 mg / L NaCl, Cl - The removal capacity was 73.65 mg / g Cl / g Anode The retention rate after 100 cycles was 75%.

[0122] The above description of the embodiments is to facilitate the understanding and use of the present application by those of ordinary skill in the art. Those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the present application is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the principles of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. An Ag-based CDI active material, characterized in that, The Ag-modifier framework material, and Ag nanoclusters dispersed therein; The modifier is at least one organic compound with the structure of Formula 1-A, Formula 1-B, or Formula 1-C. Formula 1-A; Formula 1-B; Formula 1-C; X1 and X2 are independently C or N; R1 is at least one of H, amino, alkylamino, hydroxyl, halogen, alkoxy, and trifluoromethyl. The Ag-based CDI active material, wherein the dispersed Ag nanoclusters are formed in situ, have mixed valence Ag + / Ag 0 , and the particle size of the Ag nanoclusters is 2-5 nm.

2. A method of preparing the Ag-based CDI active material of claim 1, characterized in that, The Ag source and the modifier are pre-reacted under ultrasonic assistance, followed by a solvothermal reaction.

3. The method of preparing Ag-based CDI active material according to claim 2, wherein, The Ag source includes a soluble Ag-containing compound.

4. The method of preparing Ag-based CDI active material according to claim 3, wherein, The Ag source is at least one of silver acetate, silver nitrate, silver citrate, silver trifluoroacetate, silver phosphate, silver acetylacetone, and silver tetrafluoroborate.

5. The method of preparing Ag-based CDI active material according to claim 2, wherein, The molar ratio of the Ag source to the modifier is 1:1-4.

6. The method of preparing Ag-based CDI active material according to claim 5, wherein, The molar ratio of the Ag source to the modifier is 1:1-2.

7. The method of preparing Ag-based CDI active material according to claim 2, wherein, The ultrasonic power in the pre-reaction stage is 150-200 W. The pre-reaction time is more than 0.3 h.

8. The method of preparing Ag-based CDI active material according to claim 2, wherein, The solvothermal temperature is more than 100℃. The solvothermal time is more than 1 h.

9. The method of preparing Ag-based CDI active material according to claim 8, wherein, The solvothermal temperature is 120-150℃. The solvothermal time is 2-5 h.

10. Use of the Ag-based CDI active material of claim 1 or the Ag-based CDI active material prepared by the method of any one of claims 2-9, wherein the use is for a battery, a supercapacitor, or a hybrid battery-supercapacitor. It is used as an active material for CDI adsorption of anions.

11. Use according to claim 10, wherein the compound is ###0002### It is used as an active material for CDI adsorption of anions from wastewater containing anions.

12. Use according to claim 10 or 11, wherein the compound is ###0002### The anion includes chloride.

13. A CDI electrode comprising a current collector and a CDI electrode material composited on the surface thereof, the CDI electrode material comprising an active material, a binder, and a conductive agent, characterized in that, The active material includes the Ag-based CDI active material of claim 1 or the Ag-based CDI active material prepared by the method of any one of claims 2-9.

14. The CDI electrode of claim 13, wherein, The content of the Ag-based CDI active material in the active material is more than 50 wt.%.

15. The CDI electrode of claim 13, wherein, The current collector is carbon paper, graphite paper, carbon cloth, or titanium plate.

16. The CDI electrode of claim 13, wherein, The conductive agent is at least one of acetylene black and conductive carbon black.

17. The CDI electrode of claim 13, wherein, The binder is at least one of PVDF and PTFE.

18. The CDI electrode of claim 13, wherein, The weight ratio of the active material, the binder, and the conductive agent in the active material is 75-99:1-15:1-15.

19. A CDI device, characterized by It includes the Ag-based CDI active material of claim 1 or the Ag-based CDI active material prepared by the method of any one of claims 2-9.

20. The CDI device of claim 19, wherein, It includes the CDI electrode of any one of claims 13-18.

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