Dispersion distributed nano ag / c composite CDI active material, preparation and application thereof

Abstract

This invention belongs to the field of CDI materials, specifically relating to a dispersed nano-Ag / C composite CDI active material, comprising a one-dimensional carbon rod and silver nanoparticles with a particle size of less than or equal to 10 nm dispersed on the carbon rod. This invention also provides a method for preparing the aforementioned dispersed nano-Ag / C composite CDI active material and its applications. The material described in this invention exhibits excellent CDI dechlorination activity and stability.

Description

Technical Field

[0001] This invention belongs to the field of water treatment, specifically relating to the field of CDI dechlorination technology. Background Technology

[0002] Due to population growth, industrial development, and environmental pollution, freshwater scarcity has become a significant global challenge. Seawater and brackish water desalination is considered a viable solution for producing freshwater to meet human needs. Among all deionization technologies, capacitive deionization (CDI) is a novel water treatment technology that recovers some energy while desalinating. It features low energy consumption, low cost, simple operation, and easy regeneration, and has been extensively studied in recent years.

[0003] The key to CDI (Continuous Dioxide) lies in developing high-performance electrode materials. Porous carbon electrodes are frequently used as CDI electrodes due to their good conductivity and high porosity; however, the adsorption capacity of carbon electrodes is typically below 30 mg / g, and severe side reactions during electrochemical processes lead to low charge efficiency. Ag electrode materials based on the Faraday reaction are considered to be highly efficient electrodes for next-generation CDI devices due to their high deionization capacity and charge efficiency. Faraday Ag electrode materials selectively capture Cl- through conversion reactions. - The ions exhibit extremely high potential for ion-selective separation applications. Based on charge transfer reactions, Ag shows strong ion-selective separation properties for Cl... - Captures Ag and Cl under an electrochemical field, exhibiting a high theoretical capacity (248 mAh / g). - A specific binding occurs, forming insoluble AgCl, and the reaction is reversible when the electric field is reversed. In addition, Ag electrode materials have low redox potential, high specific capacitance, and highly reversible redox reactions.

[0004] Existing technologies also report some CDI techniques involving Ag / C. For example, Chinese patent document CN115463625A discloses a nanowire-lignin-derived carbon composite aerogel, its preparation method, and its application. Chinese patent document CN113257586A discloses a method for preparing and applying a silver-carbon composite electrode material. Chinese patent document CN111777068A discloses a novel chloride ion removal material, Ti3C2T. x Preparation methods and applications of / Ag.

[0005] Although Ag electrodes have shown high applicability in CDI and have attracted widespread attention from scholars both domestically and internationally, ensuring their structural stability remains a significant challenge. Under the influence of an electric field, Ag reacts with Cl... -The formation of AgCl leads to severe volume expansion of AgCl nanoparticles (expansion rate can reach 225%), causing intergranular cracks, pulverization, and loss in Ag / C materials, severely affecting the cycling stability of the materials. Nanocrystallization is an important modification method to improve the cycling stability of Ag-based materials. Notably, nanoparticles can reduce the absolute volume change of each particle by a factor of three (cubic degrees of diameter). As a result, absolute strain is effectively mitigated, and the structural stability of the material is greatly enhanced. Furthermore, nanoparticles shorten the charge diffusion paths of ions and electrons and provide abundant electrochemical active sites. Currently, the preparation of Ag nanoparticles typically involves high-temperature (>600℃) thermal reduction of metal precursors, which inevitably leads to nanoparticle migration and sintering, significantly reducing atom utilization efficiency. In this regard, simultaneously achieving particle size control, suppression of self-aggregation, and uniform dispersion of active components in Ag nanoparticles remains a significant challenge.

[0006] Therefore, it is necessary to provide a method for preparing and applying a highly dispersed, ultrafine-sized Ag / C electrode to address the defect of volume expansion in silver-based electrode materials. Summary of the Invention

[0007] To address the issues of unsatisfactory adsorption capacity and stability of existing Ag / C CDI materials, the primary objective of this invention is to provide a diffusely distributed nano-Ag / C composite CDI active material, aiming to offer a CDI active material with excellent adsorption capacity and stability.

[0008] The second objective of this invention is to provide a method for preparing the dispersed nano-Ag / C composite CDI active material, aiming to obtain a CDI active material with ultrafine nano-size, highly dispersed distribution, improved dechlorination capacity, reduced volume expansion, and improved adsorption stability.

[0009] The third objective of this invention is to provide the application of the aforementioned dispersed nano-Ag / C composite CDI active material as a CDI active material.

[0010] The fourth objective of this invention is to provide a CDI electrode and device comprising the dispersedly distributed nano-Ag / C composite CDI active material.

[0011] To address the problems of unsatisfactory adsorption capacity, significant volume expansion, and unsatisfactory adsorption stability in Ag / C composite CDI materials, this invention provides the following improvement solutions:

[0012] A diffusely distributed nano-Ag / C composite CDI active material includes a one-dimensional carbon rod and nano-silver particles with a particle size of less than or equal to 10 nm diffusely distributed on the one-dimensional carbon rod.

[0013] This invention provides a composite material in which ultrafine-sized nano-Ag is uniformly dispersed on a one-dimensional carbon rod, and studies have shown that the material, when used in CDI treatment, can unexpectedly and significantly improve Cl... - In addition to its adsorption capacity, it can also buffer the volume expansion of Ag and improve the CDI adsorption stability of Cl.

[0014] In this invention, the content of Ag in the dispersed nano-Ag / C composite CDI active material is 70-90 wt.%, more specifically 71.81-87.45 wt.%.

[0015] The present invention also provides a method for preparing the dispersed nano-Ag / C composite CDI active material, wherein a solution containing a water-soluble Ag source and a compound of formula 1 is sealed in a pressure-resistant container and subjected to heat treatment at a temperature above 100°C to obtain a precursor; subsequently, the precursor is carbonized (also known as carbonization) at 470-700°C to obtain the final product.

[0016] HOOC-Ar-COOH

[0017] Formula 1;

[0018] The Ar is a single aromatic ring, or a polycyclic structure with two or more aromatic rings formed by parallel or conjugated single aromatic rings, and in Formula 1, the two -COOH groups are in the para position of Ar.

[0019] This invention innovatively demonstrates that pre-heating the Ag source and the compound of Formula 1 to assemble the precursor, followed by subsequent carbonization treatment and coordinated control of the carbonization temperature, can unexpectedly and significantly solve the problems caused by the characteristics of Ag in the preparation of Ag / C materials, such as easier agglomeration, large size, and insufficient exposure of CDI active sites. This can further improve the adsorption capacity of CDI. Moreover, it can effectively buffer the expansion and pulverization of Ag materials during the CDI process and improve its CDI stability.

[0020] In this invention, the water-soluble Ag source is at least one of silver acetate, silver nitrate, silver citrate, silver trifluoroacetate, silver phosphate, silver acetylacetone, and silver tetrafluoroborate.

[0021] In this invention, the compound of formula 1 is at least one organic compound having the structure of formulas A to C;

[0022]

[0023] X1 and X2 are individually C or N; R1 / R2 are individually at least one of H, amino, alkylamino, hydroxyl, halogen, alkoxy, and trifluoromethyl.

[0024] In this invention, the molar ratio of the water-soluble Ag source to Formula 1 is 1:0.5 to 4, preferably 1:1 to 2.

[0025] In this invention, the solvent in the solution includes at least one of alcohol, DMF, and DMSO.

[0026] In this invention, a heat treatment process is first used to assemble Ag and Formula 1 to form a framework precursor. Then, carbonization is carried out, and the carbonization temperature is optimized and controlled to solve the problems encountered in the preparation of Ag / C materials and improve the CDI performance of the final prepared material.

[0027] In a preferred embodiment of the present invention, a water-soluble Ag source and a compound of formula 1 are pretreated under ultrasonic assistance, followed by a subsequent heat treatment to obtain the precursor.

[0028] The precursor includes an Ag-type 1 framework material and silver nanoclusters dispersed on the Ag-type 1 framework material.

[0029] Further research in this invention shows that using this preferred process, a precursor with dispersed silver nanoclusters can be prepared. Further carbonization of the precursor at the specified temperature helps to further synergistically control the ultrafine particle size and dispersed distribution characteristics of Ag. In addition, it is beneficial to construct a richer range of sites suitable for CDI adsorption and microcavities that alleviate system expansion, thereby helping to further synergistically improve the CDI capacity and stability of the prepared material.

[0030] In this invention, there are no special requirements for the ultrasonic power; for example, it can be 100-200W, preferably 140-160W.

[0031] In this invention, the pretreatment time is more than 0.3 hours. Considering the processing efficiency, it can be further 0.3 to 2 hours, and considering the efficiency, it can be further 0.4 to 0.8 hours.

[0032] In this invention, the heat treatment temperature is 110-220℃, and can be further 115-150℃;

[0033] In this invention, the heat treatment time is more than 1 hour, preferably 2-5 hours.

[0034] In this invention, the precursor obtained by heat treatment is carbonized, and the carbonization temperature is controlled in conjunction with the heat treatment. This combination helps to control the grain size of Ag and optimize its dispersion distribution behavior, as well as the active sites and microcavity structure that are compatible with CDI. This helps to synergistically improve the CDI capacity and stability of the prepared material.

[0035] In this invention, the atmosphere during the carbonization process is an oxygen-free atmosphere, preferably at least one of nitrogen and inert gas;

[0036] Preferably, the carbonization temperature is 480–620°C, more preferably 480–520°C, and even more preferably 500±10°C. Studies have shown that the preferred temperature helps to further control the grain size and dispersion of Ag, and helps to further improve the CDI performance of the prepared material.

[0037] Preferably, the carbonization time is more than 1 hour, and more preferably 1 to 3 hours.

[0038] The present invention also provides an application of the aforementioned dispersed nano-Ag / C composite CDI active material, which is used as a CDI active material for the electro-adsorption of chlorine in chlorinated water.

[0039] This invention innovatively uses the dispersed nano-Ag / C composite CDI active material as a CDI treatment for Cl, which can meet the application requirements of CDI of Cl and can unexpectedly improve the electro-adsorption capacity and stability of Cl.

[0040] The present invention also provides a CDI electrode material, comprising an active material, wherein the active material comprises the diffusely distributed nano-Ag / C composite CDI active material.

[0041] In this invention, the content of the dispersed nano-Ag / C composite CDI active material in the active material is above 70 wt.%.

[0042] In this invention, the CDI electrode material may also contain binders and conductive agents known in the industry.

[0043] The present invention also provides a CDI electrode, comprising a current collector and a CDI electrode material composite thereon, wherein the CDI electrode material is the same as described above.

[0044] The present invention also provides a CDI device comprising the aforementioned dispersed nano-Ag / C composite CDI active material, preferably comprising the CDI electrode and CDI electrode material described in the present invention.

[0045] The CDI device, CDI electrode, and CDI electrode material described in this invention, except for the dispersed nano-Ag / C composite CDI active material described in this invention, can have conventional components, structures, and parts.

[0046] Beneficial effects:

[0047] 1. This invention provides a novel dispersed nano-Ag / C composite CDI active material, and research shows that the material, when used in CDI treatment, can unexpectedly and significantly improve Cl... - In addition to its high adsorption capacity, it can also buffer the volume expansion of Ag and improve the adsorption capacity of Cl. - CDI adsorption stability.

[0048] 2. This invention innovatively pre-treats the Ag source and the compound of Formula 1 to assemble a precursor, followed by subsequent carbonization treatment. By synergistically controlling the carbonization temperature, the CDI activity and stability of the prepared material are unexpectedly improved. For example, in an optional embodiment of this invention, the Ag prepared by carbonization at 500℃ has a particle size of 5.06 nm and is highly dispersed, exhibiting good activity against Cl in water. - It exhibits excellent electroadsorption and recycling performance, retaining 100% of its performance after 50 cycles, surpassing most current Ag-based electrode materials. When used as a CDI electrode, it showed a Cl- concentration of 159.96 mg / g in a 1000 mg / L NaCl solution at 1.4 V. - Adsorption capacity.

[0049] 3. The present invention further employs ultrasound to pretreat the Ag source and Formula 1, followed by subsequent heat treatment and carbonization at the specified temperature. This unexpectedly optimizes the CDI-adaptive physicochemical structure and can further optimize the CDI activity and stability of the prepared material. Attached Figure Description

[0050] Figure 1 The images show the XRD patterns of the AgNC-400, AgNC-500, AgNC-600, and AgNC-700 electrode materials prepared in Examples 1-2.

[0051] Figure 2 This is a TEM image of AgNC-500 prepared in Example 1. Figure 2 The inset in b is a histogram of the size distribution of Ag particles in AgNC-500.

[0052] Figure 3 TEM images of the AgNC-400, AgNC-600 and AgNC-700 electrode materials prepared in Example 2.

[0053] Figure 4 This is a TEM image of the Ag / C material prepared in Example 4.

[0054] Figure 5Thermogravimetric curves of the AgNC-400, AgNC-500, AgNC-600 and AgNC-700 electrode materials prepared for Examples 1-2 in air atmosphere.

[0055] Figure 6 a shows the cyclic voltammetric curves of AgNC-400, AgNC-500, AgNC-600, and AgNC-700 at a scan rate of 1 mV / s; Figure 6 b shows the constant current charge-discharge curves of AgNC-400, AgNC-500, AgNC-600 and AgNC-700 at 0.1 A / g; Figure 6 c represents the electrochemical impedance spectroscopy of AgNC-400, AgNC-500, AgNC-600, and AgNC-700; Figure 6 d represents the AgNC-500 cycle test at a current density of 1A / g for 1000 cycles.

[0056] Figure 7 Dechlorination performance of commercial AC electrodes, AgNC-400, AgNC-500, AgNC-600 and AgNC-700 prepared in Examples 1-2, in a constant voltage of 1.4V and 1000mg / L NaCl solution.

[0057] Figure 8 The dechlorination performance of the AgNC-500 electrode prepared in Example 1 in a 1000 mg / L NaCl solution at a voltage of 1.0-1.6 V.

[0058] Figure 9 The dechlorination performance of the AgNC-500 electrode prepared in Example 1 was tested under constant voltage of 1.2V and 50 cycles of 1000mg / L NaCl solution.

[0059] AC refers to commercially purchased activated carbon (Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., with a specific surface area of ​​1800 m²). 2 / g). Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0062] Those skilled in the art should understand that, as an explanation of the accompanying drawings of this invention, without affecting the understanding of this invention, "intensity" in the drawings can be understood as intensity, and "cycle number" can be understood as the number of cycles.

[0063] To address the issue of volume expansion in existing Ag electrodes during electrochemical dechlorination, this invention provides a method for preparing a highly dispersed, ultrafine-sized Ag / C electrode, comprising the following steps:

[0064] S1, under stirring, dissolve an Ag salt such as silver acetate in anhydrous ethanol solution to obtain solution one, and dissolve formula 1 in an organic solvent such as N,N-dimethylformamide (DMF) solution to obtain solution two;

[0065] S2, add solution two to solution one, and then sonicate for a certain time to obtain mixed solution three;

[0066] S3, the mixed solution three is transferred to and sealed in a polytetrafluoroethylene stainless steel reactor, and heated at a certain temperature for a certain time to obtain mixed solution four;

[0067] S4. After the reactor cools to room temperature, the above-obtained mixed solution is centrifuged four times, washed several times, and dried under vacuum at a certain temperature to obtain the precursor (Ag-Formula 1 framework material).

[0068] S5, the precursor is carbonized in an inert atmosphere to obtain the highly dispersed ultrafine Ag / C electrode material.

[0069] In order to achieve efficient adsorption of chloride ions, the present invention also provides a method for electro-adsorption of chloride ions, wherein the highly dispersed ultrafine Ag / C electrode material as described in any of the above embodiments is used on the electrode of a capacitive deionization device, and the chloride ions in the chloride ion solution are adsorbed by the capacitive deionization device.

[0070] Specifically, the process of using the highly dispersed ultrafine Ag / C electrode material on the electrode of a capacitive deionization device may include: mixing the highly dispersed ultrafine Ag / C electrode material, polyvinylidene fluoride and carbon black in a mass ratio of 80wt%:10wt%:10wt%, adding N-methylpyrrolidone, grinding into a slurry and then coating it onto a conductive current collector.

[0071] Furthermore, during the adsorption of chloride ions in the chloride ion solution by the aforementioned capacitor deionization device, the Cl in the chloride ion solution... - The initial concentration can be 500-3000 mg / L, and the applied voltage of the capacitor deionization device can be 1.0-1.6V.

[0072] To further illustrate the present invention, examples are given below:

[0073] Example 1

[0074] This embodiment describes a method for preparing a highly dispersed, ultrafine-sized Ag / C electrode, comprising the following steps:

[0075] (1) Under stirring, 1 mmol of silver acetate was dissolved in 50 mL of anhydrous ethanol to obtain solution one. 1 mmol of compound of formula 1 (in this case, formula A-1, with the structural formula:) was then added. Dissolve it in 5 mL of N,N-dimethylformamide (DMF) solution to obtain solution two;

[0076] (2) Add solution two to solution one, and then sonicate at 150W for 30 minutes to obtain mixed solution three;

[0077] (3) Transfer mixed solution three to a polytetrafluoroethylene stainless steel reactor (the filling rate of the solution is 50-80%) and heat it at 120°C for 2 hours to obtain mixed solution four;

[0078] (4) After the reaction vessel is cooled to room temperature, the above mixed solution is centrifuged at 10,000 rpm / min for 5 min, washed with DMF until colorless, and then washed three times alternately with anhydrous ethanol and deionized water. The Ag-form 1 precursor is obtained by drying in a vacuum oven at 60°C for 6 h.

[0079] (5) Carbonize the Ag-Form 1 precursor at 500°C for 2 hours in a N2 atmosphere to obtain the Ag / C electrode material, named AgNC-500.

[0080] See XRD diagram Figure 1 The peaks are completely consistent with the standard peaks in the Ag standard card PDF#04-004-6434, as shown in the TEM image. Figure 2 This provides a clear and intuitive understanding of the structure, size, and distribution of AgNC-500. The Ag particles have a diameter of 3-10 nm, and the D50 is around 5 nm.

[0081] Example 2

[0082] Compared with Example 1, the only difference is that the carbonization temperature in step 5 is changed; all other operations and parameters are the same as in Example 1. The experimental groups are as follows:

[0083] Group A: The carbonization temperature is 400℃, and the final material is marked as AgNC-400;

[0084] Group B: The carbonization temperature is 600℃, and the final material is marked as AgNC-600;

[0085] Group C: The carbonization temperature is 700℃, and the final material is marked as AgNC-700;

[0086] TEM for each case Figure 3 .

[0087] Example 3

[0088] Compared to Example 1, the only difference is that the parameters and conditions were changed, and the experimental groups were as follows:

[0089] Group A: Replace equation A-1 in step 1 with equation B-1 of equal weight. The final material was designated Ag / CB-500;

[0090] Group B: Replace equation A-1 in step 1 with equation C-1 of equal weight. The final material was labeled Ag / CC-500;

[0091] Group C: In step 2, the ultrasonic power is 160W and the ultrasonic time is 25min. In step 3, the solvothermal temperature is 140℃ and the time is 1.5h.

[0092] All other operations and parameters are the same as in Example 1.

[0093] Example 4

[0094] Compared to Example 1, the only difference is that in step 2, instead of ultrasonic-assisted pretreatment, mechanical stirring for 1 hour was performed to obtain a homogeneous solution. Other operations and parameters are the same as in Example 1. The TEM images of the prepared material are as follows: Figure 4 As shown, the morphological clarity of the final Ag / C material prepared is not as good as that of Example 1.

[0095] Comparative Example 1

[0096] Compared with Example 4, the only difference is that silver acetate and formula A-1 are ball-milled and mixed with ethanol, then dried, and directly subjected to the carbonization treatment in step 5 to obtain Ag / C material.

[0097] Comparative Example 2

[0098] Compared with Example 4, the only difference is that step 5 is omitted, and the Ag-form 1 precursor obtained in step 4 is directly used as the CDI active material. All other operations and parameters are the same as in Example 1.

[0099] Example 5

[0100] The purpose of this experiment was to investigate the electrochemical performance of the AgNC-400, AgNC-500, AgNC-600, and AgNC-700 electrodes described in Examples 1 and 2. The specific procedure was as follows: 8 mg of the AgNC electrode material prepared in Examples 1 and 2, 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 sonicated and stirred for 30 minutes to form a homogeneous slurry. 50 μL of the 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.

[0101] Cyclic voltammetry curves of the AgNC electrode materials obtained in Examples 1-2 were measured at a scan rate of 1 mV / s. Figure 6 a) The AgNC-400, AgNC-500, AgNC-600, and AgNC-700 electrodes all exhibited symmetrical redox peaks. The CV curves of each electrode showed 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. AgNC-500 exhibited the largest specific capacitance of 246.21 F / g at a scan rate of 1 mV / s. The charge-discharge curves of the AgNC electrode materials obtained in Examples 1-2 at a current density of 0.1 A / g were measured. Figure 6 b) The AgNC-500 showed the longest discharge time. Figure 6 c shows the electrochemical impedance spectroscopy of the AgNC electrode materials obtained in Examples 1-2. AgNC-500 shows a minimum charge transfer resistance of 2.14 Ω. Figure 6 d represents the AgNC-500 electrode material obtained in Example 2, tested for 1000 charge-discharge cycles at a current density of 1 A / g. After 1000 cycles, the capacity retention rate was >100%.

[0102] Example 6

[0103] The purpose of this experiment is to investigate the dechlorination performance of the AgNC electrode materials prepared in Examples 1-2.

[0104] CDI electrodes were prepared from commercially purchased AC and the AgNC-400, AgNC-500, AgNC-600, and AgNC-700 electrodes described in Examples 1-2 using the following method: 80 wt% of the active material, 10 wt% of acetylene black, and 10 wt% of PVDF were dissolved in 1 mL of NMP, followed by ultrasonic treatment and stirring for 30 minutes to form a homogeneous slurry. 1 mL of the mixed slurry was coated onto a titanium plate (effective area 5 × 5 cm). 2 The CDI electrodes were dried overnight at 120°C. The resulting CDI electrodes were assembled into a CDI unit, and a voltage was applied between the positive and negative electrodes. The salt solution to be treated was delivered to the CDI unit by a peristaltic pump, and the electrochemical performance of the CDI device was tested.

[0105] The applied voltage of the above-mentioned capacitor deionization device was set to 1.4V, the adsorption time to 40min, and the concentration of NaCl solution to 1000mg / L.

[0106] like Figure 7 As shown, the dechlorination capacities of the AC, AgNC-400, AgNC-500, AgNC-600 and AgNC-700 electrodes are 37.15 mg / g, 74.141 mg / g, 159.96 mg / g, 142.70 mg / g and 120.75 mg / g, respectively.

[0107] Example 7

[0108] The purpose of this experiment is to investigate the dechlorination performance of the AgNC-500 electrode material prepared in Example 1 under different voltages.

[0109] The CDI electrode of the AgNC-500 electrode described in Example 1 was prepared by the following method: 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 titanium plate (effective area 5 × 5 cm). 2 The CDI electrodes were then dried overnight at 120°C. The resulting CDI electrodes were assembled into a CDI unit, and different voltages were applied between the positive and negative electrodes. The salt solution to be treated was delivered to the CDI unit by a peristaltic pump, and the electrochemical performance of the CDI device was tested.

[0110] The applied voltage of the above-mentioned capacitor deionization device is set to 1.0-1.6V, the adsorption time is 40min, and the concentration of NaCl solution is 1000mg / L.

[0111] like Figure 8As shown, the dechlorination capacities of the AgNC-500 electrode at voltages of 1.0-1.6V are 98.55mg / g, 120.26mg / g, 159.23mg / g, and 179.96mg / g, respectively.

[0112] Example 8

[0113] The purpose of this experiment is to investigate the dechlorination cycle stability of the AgNC-500 electrode material prepared in Example 1.

[0114] The CDI electrode of the AgNC-500 electrode described in Example 1 was prepared by the following method: 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 titanium plate (effective area 5 × 5 cm). 2 The CDI electrodes were dried overnight at 120°C. The resulting CDI electrodes were assembled into CDI units, and different voltages were applied between the positive and negative electrodes. The salt solution to be treated was delivered to the CDI units by a peristaltic pump, and the electrochemical performance of the CDI device was tested.

[0115] The applied voltage of the above-mentioned capacitor deionization device was set to 1.2V, with each cycle consisting of 40 minutes of adsorption and 40 minutes of desorption, and the concentration of the NaCl solution was 1000 mg / L.

[0116] like Figure 9 As shown, the AgNC-500 electrode retains 100% of its dechlorination capacity after 50 cycles at 1.2V.

[0117] The adsorption capacity of other materials for Cl was tested using Example 6, and the effect after 50 cycles was tested using Example 8. The results are shown in Table 1:

[0118] Table 1

[0119]

[0120]

[0121] As demonstrated in Examples 1 and 3, the use of compound B-1, combined with other processes, exhibits superior synergistic performance.

[0122] As can be seen from Examples 1 and 4, by employing the pre-ultrasonic solvothermal treatment of the present invention, it is possible to unexpectedly obtain an Ag-type 1 framework precursor with Ag cluster distribution. Further carbonization of this precursor can further improve the morphology of the prepared material and help to further improve the CDI performance of the prepared material.

[0123] The above technical solutions of the present invention are merely preferred embodiments and do not limit the patent scope of the present invention. All equivalent structural transformations made under the technical concept of the present invention using the contents of the specification and drawings of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A dispersed nano-Ag / C composite CDI active material, characterized in that, This includes one-dimensional carbon rods, as well as silver nanoparticles with a particle size of less than or equal to 10 nm that are dispersed on the carbon rods. The method for preparing the diffusely distributed nano-Ag / C composite CDI active material is as follows: a solution containing a water-soluble Ag source and a compound of formula 1 is sealed in a pressure-resistant container and heat-treated at a temperature above 100°C to obtain a precursor; then the precursor is carbonized at 470~700°C to obtain the final product. HOOC-Ar-COOH Formula 1; The Ar is a single aromatic ring, or a polycyclic structure with two or more aromatic rings formed by parallel or conjugated single aromatic rings, and in Formula 1, the two -COOH groups are in the para position of Ar.

2. The dispersed nano-Ag / C composite CDI active material as described in claim 1, characterized in that, In the dispersed nano-Ag / C composite CDI active material, the Ag content is 70~90 wt.%.

3. The dispersed nano-Ag / C composite CDI active material as described in claim 2, characterized in that, In the dispersed nano-Ag / C composite CDI active material, the Ag content is 71.81~87.45 wt.%.

4. A method for preparing the dispersedly distributed nano-Ag / C composite CDI active material according to any one of claims 1 to 3, characterized in that, A solution containing a water-soluble Ag source and a compound of formula 1 is sealed in a pressure-resistant container and heat-treated at a temperature above 100°C to obtain a precursor; the precursor is then carbonized at 470~700°C to obtain the final product. HOOC-Ar-COOH Formula 1; The Ar is a single aromatic ring, or a polycyclic structure with two or more aromatic rings formed by parallel or conjugated single aromatic rings, and in Formula 1, the two -COOH groups are in the para position of Ar.

5. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The water-soluble Ag source is at least one of silver acetate, silver nitrate, silver citrate, silver trifluoroacetate, silver phosphate, silver acetylacetone, and silver tetrafluoroborate.

6. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The compound of formula 1 is at least one organic compound having the structure of formulas A to C; Formula A; Formula B; Formula C; X1 and X2 are each C; R1 and R2 are each H or amino groups.

7. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 6, characterized in that, The molar ratio of the water-soluble Ag source to Formula 1 is 1:0.5~4.

8. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 7, characterized in that, The molar ratio of the water-soluble Ag source to Formula 1 is 1:1~2.

9. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The solvent in the solution contains at least one of alcohol, DMF, and DMSO.

10. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The water-soluble Ag source and the compound of formula 1 were pretreated under ultrasonic assistance, followed by subsequent heat treatment to obtain the precursor. The precursor includes an Ag-type 1 framework material and silver nanoclusters dispersed on the Ag-type 1 framework material.

11. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 10, characterized in that, The ultrasonic power is 100~200W.

12. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 11, characterized in that, The ultrasonic power is 140~160W.

13. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 10, characterized in that, The pretreatment time is more than 0.3 hours.

14. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The heat treatment temperature is 110-220℃.

15. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 14, characterized in that, The heat treatment time is more than 1 hour.

16. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 15, characterized in that, The heat treatment time is 2-5 hours.

17. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The carbonization process is carried out in an oxygen-free atmosphere.

18. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 17, characterized in that, The atmosphere during the carbonization process is at least one of nitrogen or an inert gas.

19. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The carbonization temperature is 480~620℃.

20. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The carbonization temperature is 480~520℃.

21. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The carbonization temperature is 500±10℃.

22. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 4, characterized in that, The carbonization time is more than 1 hour.

23. The method for preparing the dispersedly distributed nano-Ag / C composite CDI active material as described in claim 22, characterized in that, The carbonization time is 1 to 3 hours.

24. The application of a dispersed nano-Ag / C composite CDI active material according to any one of claims 1 to 3 or a dispersed nano-Ag / C composite CDI active material prepared by the preparation method according to any one of claims 4 to 23, characterized in that, It was used as a CDI active material for the electro-adsorption of chlorine in chlorinated water.

25. A CDI electrode material, comprising an active material, characterized in that, The active material comprises the dispersed nano-Ag / C composite CDI active material according to any one of claims 1 to 3 or the dispersed nano-Ag / C composite CDI active material prepared by the preparation method according to any one of claims 4 to 23.

26. The CDI electrode material as described in claim 25, characterized in that, In the active material, the content of the dispersed nano-Ag / C composite CDI active material is above 70 wt.%.

27. The CDI electrode material as described in claim 25, characterized in that, The CDI electrode material also includes a binder and a conductive agent.

28. A CDI electrode, comprising a current collector and a CDI electrode material composite thereon, characterized in that, The CDI electrode material is the CDI electrode material according to any one of claims 25 to 27.

29. A CDI device, characterized in that, The material comprises the dispersed nano-Ag / C composite CDI active material according to any one of claims 1 to 3 or the dispersed nano-Ag / C composite CDI active material prepared by the preparation method according to any one of claims 4 to 23.

30. The CDI device as claimed in claim 29, characterized in that, It includes the CDI electrode material as described in any one of claims 25 to 27.

31. The CDI device as claimed in claim 29, characterized in that, It includes the CDI electrode as described in claim 28.

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