Flowing electrode capacitive devices, systems, preparation and applications

Abstract

The application provides a flow electrode capacitor device, system, preparation and application. The flow electrode capacitor device comprises a first current collector, a cation exchange membrane, a liquid inlet separator, an anion exchange membrane and a second current collector arranged in sequence. The working surfaces of the first current collector and the second current collector are respectively provided with a first flow channel and a second flow channel, and at least one of the first flow channel and the second flow channel is a mesh flow channel. The mesh flow channels of the first current collector and the second current collector are cross-linked and intercommunicating dispersed flow channels, and the included angle and length of the flow channels are optimized. The dispersed flow field generated by the cross-linked and intercommunicating flow channels can effectively reduce the flow resistance of the electrode slurry, so that the electrode particles are uniformly distributed in the flow channels, the continuous aggregation or sedimentation process of the particles in the flow channels is avoided, the electron conduction is expanded to the center area of the flow channels, and the charge transfer process and ion capture efficiency of the electrode slurry are strengthened.

Description

Technical Field

[0001] This invention relates to the field of electrically driven capacitors, and more particularly to flowing electrode capacitor devices, systems, preparation, and applications. Background Technology

[0002] High-salinity wastewater treatment remains a significant challenge to the ever-increasing demand for freshwater, leading to the development of various seawater desalination technologies. Electro-driven capacitive deionization (FCDI) is a promising technology for high-salinity wastewater treatment and seawater desalination due to its low energy consumption and environmental friendliness. Flow-electrode capacitive deionization (FCDI) utilizes a flowing electrode slurry and theoretically possesses pseudo-infinite desalination capacity, allowing for long-term operation without additional regeneration steps. Compared to reverse osmosis and multi-stage evaporation, FCDI further reduces energy consumption and improves seawater desalination efficiency.

[0003] The flow channel structure in FCDI devices has been shown to enhance the fluidity of the electrode slurry. However, conventional FCDI devices exhibit low charge transfer processes and ion capture efficiency. Summary of the Invention

[0004] The main objective of this invention is to provide a flow electrode capacitor device, system, preparation, and application to solve the technical problems of low charge transfer process and ion capture efficiency in traditional FCDI devices.

[0005] To achieve the above objectives, the present invention provides a flowing electrode capacitor device, comprising a first current collector, a cation exchange membrane, a liquid inlet baffle, an anion exchange membrane, and a second current collector arranged sequentially.

[0006] The working surfaces of the first and second current collectors each have a first flow channel and a second flow channel, respectively, and at least one of the first and second flow channels is a mesh flow channel. The working surfaces are the surfaces of the first and second current collectors facing the inlet baffle.

[0007] The mesh flow channel includes multiple mesh units. In each mesh unit, the included angle between any two adjacent flow channel sides is greater than 90°. The depth of the flow channel side is 1-3 mm and the width is 1-4 mm. The flow channel area corresponding to the total length of the mesh flow channel is 11.38-22.22% of the total area of ​​the working surface.

[0008] According to an embodiment of this application, at least some of the mesh cells are the same, and their outlines are all regular polygons, with the number of sides of the regular polygons being 5 to 6.

[0009] According to an embodiment of this application, the mesh flow channel includes a flow channel frame, the mesh flow channel is disposed in the area surrounded by the flow channel frame, and is connected to all the frames of the flow channel frame.

[0010] According to an embodiment of this application, a row of grid cells near the horizontal border of the flow channel are all connected to the horizontal border through their ends.

[0011] A column of grid cells on the vertical border near the flow channel edge are all connected to the vertical border in close proximity through the flow channel edge.

[0012] According to an embodiment of this application, both the first current collector and the second current collector include an inlet and an outlet that are connected to the flow channel frame.

[0013] According to an embodiment of this application, the depth of the solution cavity of the liquid inlet baffle is 1 to 4 mm.

[0014] The projections of the first flow channel and the second flow channel along the thickness direction of the flow electrode capacitor device onto the liquid inlet baffle are both located within the solution cavity.

[0015] According to an embodiment of this application, it further includes two end plates, two flexible gaskets, and fasteners. One end plate, one flexible gasket, the first current collector, the cation exchange membrane, the liquid inlet baffle, the anion exchange membrane, the second current collector, the other flexible gasket, and one end plate are arranged in sequence and fixed together by the fasteners.

[0016] This application also provides a flowing electrode capacitor system, including the above-described flowing electrode capacitor device, a first delivery pump, a second delivery pump, a third delivery pump, an electrode slurry, and a power supply.

[0017] The first delivery pump and the first collector form a first circulation channel, the second delivery pump and the second collector form a second circulation channel, and the third delivery pump and the inlet baffle form a third circulation channel.

[0018] The electrode slurry is located in the first circulation channel and the second circulation channel. The electrode slurry includes activated carbon, carbon nanotubes, carbon black and sodium chloride. The activated carbon accounts for 5-20% of the mass of the electrode slurry, the carbon nanotubes account for 0.1-1% of the mass of the electrode slurry, the carbon black accounts for 0.1-1% of the mass of the electrode slurry, and the sodium chloride accounts for 0.1-2% of the mass of the electrode slurry.

[0019] The positive terminal of the power supply is connected to the first current collector, and the negative terminal is connected to the second current collector.

[0020] This application also provides a method for fabricating a flowing electrode capacitor system, comprising the following steps:

[0021] Carbon nanotubes and conductive carbon black are mixed in a 1:1 ratio to obtain a conductive additive.

[0022] Activated carbon and 1000 mg / L sodium chloride solution were mixed at a mass ratio of 2.5–20:100, and conductive additives were added at a solid-liquid ratio of 0.2–2 g:100 ml. The mixture was stirred for 12 hours to obtain an electrode slurry.

[0023] After ultrasonically dispersing the electrode slurry for 30 minutes, it is introduced into the aforementioned flowing electrode capacitor device.

[0024] This application also provides an application of the above-mentioned flowing electrode capacitor system in water treatment, including the following steps:

[0025] The water to be treated is introduced into the solution chamber of the inlet baffle and circulated by the third delivery pump.

[0026] The electrode slurry is introduced into the first channel of the first current collector and circulated by the first delivery pump.

[0027] The electrode slurry is introduced into the second channel of the second current collector and circulated by the second delivery pump.

[0028] Desalination is carried out by passing a preset electric field through the first current collector and the second current collector for 60 to 1800 minutes.

[0029] In the aforementioned flowing electrode capacitor device, the mesh channels of the first current collector and the second current collector are cross-linked and interconnected dispersed channels, and the included angle and length of the channels have been optimized. The dispersed flow field generated by such cross-linked and interconnected channels can effectively reduce the flow resistance of the electrode slurry, so that the electrode particles are evenly distributed in the channels, avoiding the continuous aggregation or sedimentation of particles in the channels, which is conducive to the extension of electron conduction to the central region of the channels, and enhances the charge transfer process and ion capture efficiency of the electrode slurry. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the flow electrode capacitor deionization device in this invention;

[0032] Figure 2 This is a schematic diagram of the operation of the flow electrode capacitor deionization device in this invention;

[0033] Figure 3 The flow channel structures of different types of graphite plates in this invention are shown in (a) rectangular cavity (RC), (b) serpentine flow channel (SS), and (c) hexagonal honeycomb flow channel (HH).

[0034] Figure 4 This is a schematic diagram of the hexagonal honeycomb flow channel in this invention;

[0035] Figure 5 The desalination performance of different types of flow channels in the FCDI process in Example 1 of the present invention includes (a) changes in brine concentration, (b) induced voltage, (c) SR and ASRR, and (d) CE and ENRS.

[0036] Figure 6 The desalination performance of different types of flow channels under electrode slurry conditions with different carbon contents in Example 2 of the present invention includes: (a) brine concentration change of RC-FCDI system, (b) brine concentration change of SS-FCDI system, (c) brine concentration change of HH-FCDI system, (d) SR parameters of three FCDI systems, (f) ASRR parameters of three FCDI systems, and (e) CE parameters of three FCDI systems.

[0037] Figure 7 The effects of different flow rates on the performance of the HH-FCDI system in Example 3 of the present invention are as follows: (a) changes in brine concentration, (b) induced voltage, (c) SR and average voltage, and (d) ASRR and ENRS.

[0038] Figure 8 The effects of different initial concentrations on the performance of the HH-FCDI system in Example 4 of this invention are shown: (a) changes in brine concentration, (b) induced voltage, (c) SR and average voltage, and (d) ASRR and ENRS.

[0039] Figure 9 The following are examples of the (a) particle migration mechanism, (b) CFD results, and (c) long-term operating performance of the rectangular channel FCDI system in Embodiment 5 of the present invention.

[0040] Figure 10 The following are examples of the serpentine flow channel FCDI system in Embodiment 5 of the present invention: (a) particle migration mechanism, (b) CFD results, and (c) long-term FCDI performance.

[0041] Figure 11 This refers to the particle migration mechanism (a) of the hexagonal honeycomb channel FCDI system in Embodiment 5 of the present invention.

[0042] (b) CFD results and (c) FCDI long-term operational performance.

[0043] 100, First current collector; 200, Cation exchange membrane; 300, Inlet baffle; 400, Anion exchange membrane; 500, Second current collector; 600, Mesh channel; 610, Mesh unit; 611, Channel edge;

[0044] 700, Flow channel frame; 710, Horizontal frame; 720, Vertical frame; 800, End plate; 900, Flexible gasket;

[0045] 1000. Fasteners;

[0046] 10. Flowing electrode capacitor device; 21. First transfer pump; 22. Second transfer pump; 23. Third transfer pump; 50. Power supply; 60. Magnetic stirrer; 80. Electrode slurry storage tank; 90. Brine storage tank; 30. Computer control terminal.

[0047] The realization of the objective, functional characteristics and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0048] 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.

[0049] It should be noted that all directional indicators (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0050] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0051] Furthermore, 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 those 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.

[0052] The applicant has conducted extensive research on the technical problems of low charge transfer process and ion capture efficiency in traditional FCDI devices. The research revealed that traditional FCDI devices mostly employ a single-track serpentine flow channel. This single-track serpentine flow channel generates significant flow resistance at bends, causing excessive local hydraulic pressure, leading to electrode slurry overflow and resulting in severe electrode accumulation and flow channel blockage. Based on the two-phase flow characteristics of the electrode slurry—that is, the distribution (aggregation or dispersion) of electrode particles is constrained by the hydrodynamic behavior of the liquid electrolyte—and the flow channel structure governs the flow state of the liquid electrolyte, the flow channel structure plays a crucial role in fluid guidance and electron supply during the FCDI process, significantly impacting electrode slurry flowability, particle migration, and the construction of the charge conduction network.

[0053] Based on this, the present invention provides a flowing electrode capacitor device 10, see [link to relevant documentation]. Figure 1 and Figure 4 It includes a first current collector 100, a cation exchange membrane 200, an inlet baffle 300, an anion exchange membrane 400, and a second current collector 500 arranged sequentially. The working surfaces of the first current collector 100 and the second current collector 500 respectively have a first flow channel and a second flow channel.

[0054] The first current collector 100, the cation exchange membrane 200, the inlet baffle 300, the anion exchange membrane 400, and the second current collector 500 are tightly fitted together, such as by fasteners 1000. The surfaces of the first current collector 100 and the second current collector 500 facing the inlet baffle 300 are called the working surfaces.

[0055] The materials of the first current collector 100 and the second current collector 500 are not specifically limited, and include a variety of materials, such as graphite plate structures. The first current collector 100 and the second current collector 500 are formed with grooves of corresponding shapes on the working surface by means of mechanical etching or chemical etching, as needed, to obtain the corresponding first flow channel and second flow channel.

[0056] The cation exchange membrane 200 is in close contact with the working surface of the first current collector 100, and cooperates with the first flow channel to form a chamber that constrains the flow of the electrode slurry. The anion exchange membrane 400 is in close contact with the working surface of the second current collector 500, and cooperates with the second flow channel to form another chamber that constrains the flow of the electrode slurry. These two chambers are independent of each other.

[0057] The inlet baffle 300 has a receiving cavity, which is continuous along its thickness direction, meaning one side is in contact with the anion exchange membrane 400 and the other side is in contact with the cation exchange membrane 200. In other words, the inlet baffle 300 is a hollow structure, providing a chamber for the treatment of water flow. Therefore, overall, the flow electrode capacitor device 10 includes a three-chamber structure arranged sequentially along the stacking direction.

[0058] At least one of the first and second flow channels is a mesh flow channel 600 (also referred to as a distributed flow channel structure). The mesh flow channel 600 includes multiple mesh cells 610. In each mesh cell 610, the included angle between any two adjacent flow channel edges 611 is greater than 90°. The depth of the flow channel edges 611 is 1–3 mm, and the width is 1–4 mm. The flow channel area corresponding to the total length of the mesh flow channel 600 is 11.38–22.22% of the total area of ​​the working surface.

[0059] See Figure 1 and Figure 4 The mesh flow channel 600 comprises multiple mesh cells 610. These mesh cells 610 are arranged in multiple rows and columns, forming the mesh flow channel 600. Each mesh cell 610 includes several flow channel edges 611, such as 5, 6, 7, or 10 flow channel edges 611. All flow channel edges 611 are connected end-to-end to form the mesh cell 610. Adjacent mesh cells 610 share a portion of the flow channel edges 611, such as sharing one flow channel edge 611.

[0060] The mesh cells 610 within the mesh flow channel 600 may be of one or more types. For example, all mesh cells 610 may be hexagonal mesh cells 610 with 6 flow channel sides 611, or all mesh cells 610 may be pentagonal mesh cells 610 with 5 flow channel sides 611.

[0061] For example, all grid cells 610 include both hexagonal grid cells 610 and pentagonal grid cells 610. When there are multiple types of grid cells 610 within the mesh flow channel 600, the number of different types of grid cells 610 does not need to be consistent, and they can be arranged as needed.

[0062] Regardless of the specific grid cell 610 described above, in a single grid cell 610, the included angle between any two adjacent flow channel edges 611 is greater than 90°, and the depth of the flow channel edge 611 is 1–3 mm, and the width is 1–4 mm. When the included angle between any two adjacent flow channel edges 611 is greater than 90°, the electrode slurry encounters less resistance when flowing from one flow channel edge 611 to the adjacent flow channel edge 611.

[0063] The total length of the mesh channel 600 is the sum of the lengths of the channel edges 611 of all grid cells 610 and the lengths of other channel portions excluding grid cells 610. The product of the total length of the mesh channel 600 and the width of the channel edges 611 is the channel area corresponding to the mesh channel 600. The channel area corresponding to the total length of the mesh channel 600 is 11.38% to 22.22% of the total area of ​​the working surface, ensuring that the total length of the mesh channel 600 is as long as possible, increasing the capacity of the electrode slurry within the mesh channel 600, and enhancing the processing capacity.

[0064] In the aforementioned flowing electrode capacitor device 10, the mesh channels 600 of the first current collector 100 and the second current collector 500 are cross-linked and interconnected dispersive channels, and the included angle and length of the channels have been optimized. The dispersive flow field generated by such cross-linked and interconnected channels can effectively reduce the flow resistance of the electrode slurry, so that the electrode particles are evenly distributed in the channels, avoiding the continuous aggregation or sedimentation of particles in the channels, which is conducive to the extension of electron conduction to the central region of the channels, and enhances the charge transfer process and ion capture efficiency of the electrode slurry.

[0065] In some embodiments, see Figure 4 In the plurality of mesh units 610, at least some of the mesh units 610 are identical, and their outlines are all regular polygons with a side length of 5 to 6. In this case, the mesh units 610 have regular shapes, which facilitates etching.

[0066] For example, the regular polygon has 6 sides. The mesh channel 600 is a hexagonal honeycomb channel structure. The hexagonal honeycomb channel constructs interconnected channels, which can efficiently divert and guide the electrode slurry, greatly reducing the flow resistance of the electrode slurry and ensuring its fluidity. The fluidity optimization caused by the channel structure can suppress excessive accumulation or sedimentation of electrode particles, which is conducive to the dynamic aggregation of electrode particles and the construction of a charge penetration network, thereby enhancing its charge transport.

[0067] Specifically, the flow channel structure is supported by a graphite plate engraving. Within the flow channel area, hexagons of the same size are arranged in a honeycomb pattern. The intervals between each hexagon are the flow channels for the electrode slurry. The depth of each flow channel is set to 2 mm, and the area of ​​the flow channel region is 50 × 40 mm, with an effective area of ​​10.24–20 cm². 2 The corresponding total flow channel length is 512 mm, and the effective flow channel volume is 2.04–4 cm³. 3 .

[0068] Of course, in some embodiments, the outline of the grid cell 610 may also be a non-regular polygon.

[0069] In some embodiments, the mesh flow channel 600 includes a flow channel edge 611 frame, the mesh flow channel 600 is disposed in the area surrounded by the flow channel edge 611 frame, and is connected to all the borders of the flow channel edge 611 frame.

[0070] With this configuration, the flow channels within the mesh flow channel 600 are more abundant, and there are more inlets for the electrode slurry to enter the flow channel side frame 611, reducing the congestion of the electrode slurry entering the flow channel side frame 611.

[0071] In some embodiments, a row of grid cells 610 near the horizontal frame 710 of the flow channel edge 611 is connected to the horizontal frame 710 via their ends. A column of grid cells 610 near the vertical frame 720 of the flow channel edge 611 is closely connected to the vertical frame 720 via the flow channel edge 611.

[0072] The end of the grid cell 610 is the intersection point of two adjacent flow channel edges 611 of the grid cell 610. A row of the grid cells 610 near the horizontal frame 710 of the flow channel edge 611 frame is connected to the horizontal frame 710 through a short flow channel.

[0073] A column of grid cells 610 near the vertical frame 720 of the flow channel edge 611 are all closely connected to the vertical frame 720 through the flow channel edge 611. For example, the vertical frame 720 and the flow channel edge 611 are parallel and in contact, and they partially overlap, or they do not overlap but only contact.

[0074] In some embodiments, both the first current collector 100 and the second current collector 500 include an inlet and an outlet respectively communicating with the flow channel side frame 611. The electrode slurry enters from the inlet and flows out from the outlet.

[0075] In some embodiments, the depth of the solution cavity of the inlet baffle 300 is 1–4 mm. The projections of the first flow channel and the second flow channel along the thickness direction of the flow electrode capacitor device 10 onto the inlet baffle 300 are both located within the solution cavity.

[0076] The solution chamber of the inlet baffle 300 is a cavity that extends through the thickness direction, with a depth of 1–4 mm. One side is in contact with the anion exchange membrane 400, and the other side is in contact with the cation exchange membrane 200. Both the first and second flow channels are located within the solution chamber.

[0077] In some embodiments, the device further includes two end plates 800, two flexible gaskets 900, and fasteners 1000. One end plate 800, one flexible gasket 900, the first current collector 100, the cation exchange membrane 200, the liquid inlet baffle 300, the anion exchange membrane 400, the second current collector 500, the other flexible gasket 900, and one end plate 800 are arranged in sequence and fixed together by the fasteners 1000.

[0078] For example, the flow electrode capacitor device 10 is constructed sequentially from an acrylic end plate 800, a silicone gasket (flexible gasket 900), an anode graphite plate (first current collector 100), an anion exchange membrane 400, a brine compartment, a cation exchange membrane 200, a cathode graphite plate (second current collector 500), the silicone gasket (flexible gasket 900), and the end plate 800. These components are assembled in series using screws and nuts (fasteners 1000) in a stacked manner to ensure the sealing of the FCDI device.

[0079] This application also provides a flowing electrode capacitor system, including the aforementioned flowing electrode capacitor device 10 (FCDI device), a first delivery pump 21, a second delivery pump 22, a third delivery pump 23, electrode slurry, and a power supply 50. The first delivery pump 21 and the first current collector 100 form a first circulation channel, the second delivery pump 22 and the second current collector 500 form a second circulation channel, and the third delivery pump 23 and the inlet baffle 300 form a third circulation channel. The specific structures of the first delivery pump 21, the second delivery pump 22, and the third delivery pump 23 are not limited, such as peristaltic pumps.

[0080] The electrode slurry is located within the first and second circulation channels. The electrode slurry comprises activated carbon, carbon nanotubes, carbon black, and sodium chloride. The activated carbon comprises 5-20% of the electrode slurry mass, the carbon nanotubes comprise 0.1-1% of the electrode slurry mass, the carbon black comprises 0.1-1% of the electrode slurry mass, and the sodium chloride comprises 0.1-2% of the electrode slurry mass. The activated carbon, as a carrier for adsorbing target ions, needs to maintain a high activated carbon content. The carbon black, carbon nanotubes, and sodium chloride electrolyte effectively promote the formation of a conductive network in the slurry, improving its conductivity; however, excessive content can lead to poor slurry flowability and blockage of the device's flow channels. The positive terminal of the power supply 50 is connected to the first current collector 100, and the negative terminal is connected to the second current collector 500.

[0081] Taking the introduction of brine through the inlet baffle 300 as an example, the specific working principle is as follows:

[0082] The slurry is pumped to the cathode / anode electrode chambers on both sides of the FCDI device. Each electrode chamber is constructed of graphite current collectors with etched flow channels, providing pathways for the slurry flow. Additionally, a brine chamber is constructed using anion / cation exchange membrane 200 and a partition, which also serves to isolate the electrode slurry from the brine. Under the influence of an applied electric field, charged ions in the brine selectively permeate through the ion exchange membrane into the electrode slurry and are stored within the electric double layer on the electrode particle surface, thus completing the desalination process. Simultaneously, the two electrode slurries, after adsorbing anions and cations, are pumped out of the FCDI device for mixing and regeneration, and then recycled.

[0083] This application also provides a method for fabricating a flowing electrode capacitor system, comprising the following steps:

[0084] Carbon nanotubes and conductive carbon black are mixed in a 1:1 ratio to obtain a conductive additive.

[0085] The carbon nanotubes were sourced from LB120-50 purchased from Lion Corporation of Japan, and the conductive carbon black was sourced from EPC-600JD purchased from Lion Corporation of Japan.

[0086] Activated carbon and 1000 mg / L sodium chloride solution were mixed at a mass ratio of 2.5–20:100, and conductive additives were added at a solid-liquid ratio of 0.2–2 g:100 ml. The mixture was stirred for 12 hours to obtain an electrode slurry.

[0087] After ultrasonically dispersing the electrode slurry for 30 minutes, it is introduced into the aforementioned flowing electrode capacitor device 10.

[0088] For example, activated carbon, carbon nanotubes and carbon black are mixed with sodium chloride electrolyte and continuously stirred to ensure that the particles are completely wetted to obtain the ternary carbon composite flow electrode material. Before use, the slurry needs to be ultrasonically treated to disperse it.

[0089] Specifically, activated carbon is mixed with a 1000 mg / L sodium chloride solution at a mass ratio of 2.5–20:100, and a conductive additive is added at a solid-liquid ratio of 0.2–2 g:100 ml. The conductive additive is a 1:1 mixture of carbon nanotubes and conductive carbon black. The electrode slurry needs to be stirred for 12 hours to ensure uniform mixing; the electrode slurry needs to be ultrasonically dispersed for 30 minutes before use to ensure its dispersibility.

[0090] This application also provides an application of the above-mentioned flowing electrode capacitor system in water treatment, including the following steps:

[0091] The water to be treated is introduced into the solution chamber of the liquid inlet baffle 300 and circulated by the third delivery pump 23.

[0092] The electrode slurry is introduced into the first flow channel of the first current collector 100 and circulated by the first delivery pump 21.

[0093] The electrode slurry is introduced into the second flow channel of the second current collector 500 and circulated by the second delivery pump 22.

[0094] After a preset electric field of 60 to 1800 is introduced into the first current collector 100 and the second current collector 500, desalination is performed.

[0095] For example, it includes the following steps:

[0096] S01, the device components in the flowing electrode capacitor deionization device are assembled in series by screws and nuts in a stacked manner, and arranged in the order of electrode chamber, brine chamber, and electrode chamber at intervals.

[0097] S02, the electrode slurry and brine are pumped into the inlet of the FCDI device by a peristaltic pump, so that they enter the corresponding chambers and circulate in the FCDI device.

[0098] S03, after setting the preset electric field parameters and reaction time, a pulsed electric field is provided to the current collector of the FCDI device to drive the FCDI device to desalinate.

[0099] like Figure 2 As shown, the FCDI system mainly includes a peristaltic pump, a conductivity meter, an FCDI electrode assembly, a magnetic stirrer 60, a power supply tester (power supply 50), an electrode slurry storage tank 80, a brine storage tank 90, and a computer control terminal 30. During operation, under the action of the peristaltic pump, the brine solution enters the FCDI device at a certain flow rate, and then circulates between the brine storage tank and the FCDI device. For the electrode slurry, this study adopts a short-circuit closed-loop operation mode, that is, under the action of the peristaltic pump, the electrode slurry enters the cathode chamber and the anode chamber respectively, and then the two slurries merge into the electrode slurry storage tank, maintaining circulation. The power supply 50 tester applies an electric field to the FCDI device and records the changes in induced current (I) or induced voltage (V) in real time. Furthermore, the conductivity in the brine solution is monitored and recorded in real time using a conductivity meter connected to the computer. Without affecting the understanding of this invention, in FCDI, the following parameters are considered: C effluent concentration, initial CO concentration, (C / CO) effluent concentration change, and ASRR (μmol / cm³). -2 min -1 Average desalination efficiency, CE (%) current efficiency, SR desalination efficiency (%), Em (kWh mol) -1 Energy consumption and ENRS (μmol J) -1 Energy efficiency is used to evaluate desalination capacity.

[0100] To showcase the advantages of the special structure, three flow channel structures were designed: a rectangular cavity flow channel, a single-serpentine flow channel, and a hexagonal-honeycomb flow channel, abbreviated as RC-channel, SS-channel, and HH-channel, respectively. The corresponding FCDI units are RC-FCDI, SS-FCDI, and HH-FCDI, respectively. All flow channel structures were engraved from graphite plates. Figure 3 As shown. The channel depth is set to 2mm, and the channel area is 50×40mm. The effective areas of the RC-channel, SS-channel, and HH-channel are 20cm². 2 10.88cm 2 and 10.99cm 2 Calculations show that the corresponding total channel lengths are 50mm, 544mm, and 512mm, respectively. Each FCDI electrode device (dimensions: 90mm × 80mm × 7mm) consists of an acrylic end plate, a graphite plate, an anion exchange membrane, a compartment, and a cation exchange membrane, all fixed together with bolts. The effective area is the channel area used for slurry flow, i.e., the channel area corresponding to the total length of all channels; the channel region area refers to the area of ​​the rectangular region formed by etching the channels, i.e., the area enclosed by the flow frame.

[0101] Based on the above embodiments, and to facilitate understanding by those skilled in the art, examples are provided below:

[0102] Example 1

[0103] A ternary carbon composite material was used as the electrode slurry, wherein the mass fraction of activated carbon was 5.0 wt.% and the mass fraction of carbon black + carbon nanotubes was 1.0 wt.%. Pulsed electric field parameters were set: pulse frequency of 5 Hz, duty cycle of 70%, and pulse intensity of 90 mA. The initial salt solution concentration was 7500 mg / L. -1 (Electrical conductivity is 12189 μS cm⁻¹) -1 The desalination performance of FCDI was tested for three different types of flow channels.

[0104] like Figure 5 As shown, the desalination performance of the three FCDI systems exhibits significant differences. Figure 5 (c) It can be seen that the HH-FCDI system at a concentration of 7500 mg L -1The HH-FCDI system achieved a higher SR (51.28%) in the brine, compared to only 39.31% and 18.62% for the SS-FCDI and RC-FCDI systems, respectively. Correspondingly, the HH-FCDI system exhibited a faster desalination rate, with an ASRR of 7.82 μmol / cm³. -2 min -1 These are 1.31 and 4.32 times that of the SS-FCDI and RC-FCDI systems, respectively. Similarly, by Figure 5 (d) It can be seen that the CE of the HH-FCDI system (91.23%) is still better than that of RC-FCDI (76.69%) and SS-FCDI (85.51%), and the energy efficiency (ENRS) of the system reaches 15.31 μmol J. -1 It is significantly higher than RC-FCDI (11.16 μmol J). -1 ) and SS-FCDI (12.72 μmol J -1 This indicates that the HH-FCDI system exhibits excellent ion capture efficiency.

[0105] Example 2

[0106] A ternary carbon composite material was used as the electrode slurry, with different mass fractions of activated carbon (2.5, 5.0, 12.5, and 20 wt.%), and a mass fraction of carbon black + carbon nanotubes of 1.0 wt.%. Pulsed electric field parameters were set: pulse frequency of 5 Hz, duty cycle of 70%, and pulse intensity of 90 mA. The initial salt solution concentration was 7500 mg / L. -1 (Electrical conductivity is 12189 μS cm⁻¹) -1 The desalination performance of FCDI under different carbon loadings was tested.

[0107] like Figure 6 As shown, with increasing carbon loading, the effluent concentration (C / CO) of both the RC-FCDI and HH-FCDI systems continuously decreased. The system SR reached its maximum at a carbon loading of 20 wt.%, at 45.47% and 63.42%, respectively, with corresponding ASRR of 3.95 and 9.45 μmol / cm³, respectively. -2 min -1 For SS-FCDI, when the carbon loading increased from 12.5 wt.% to 20 wt.%, the system's SR and ASRR decreased significantly, to only 41.63% and 6.37 μmol cm⁻¹, respectively. -2 min -1 .

[0108] Excessive loading (20 wt.%) causes a surge in electrode slurry viscosity. Furthermore, the narrow, continuous bends in the flow channels further weaken the slurry's flowability in the SS-FCDI system, leading to significant electrode particle retention and blockage, which severely impacts the system's ion capture efficiency. In contrast, the interconnected honeycomb flow channels in the HH-FCDI system guide and divert the electrode slurry, effectively mitigating the reduced flowability caused by excessively high viscosity and improving the slurry's flow efficiency.

[0109] Furthermore, when the carbon loading increased from 12.5 wt.% to 20 wt.%, the trends in SR and ASRR in the HH-FCDI system were alleviated, and the system CE decreased significantly, indicating that excessively high carbon loading severely weakens the fluidity of the electrode slurry. Based on the above analysis, we will use an electrode slurry with a carbon loading of 12.5 wt.% for our next step of work.

[0110] Example 3

[0111] A ternary carbon composite material was used as the electrode slurry, wherein the mass fraction of activated carbon was 12.5 wt.% and the mass fraction of carbon black + carbon nanotubes was 1.0 wt.%. Pulsed electric field parameters were set: pulse frequency of 5 Hz, duty cycle of 70%, and pulse intensity of 90 mA. The initial salt solution concentration was 7500 mg / L. -1 (Electrical conductivity is 12189 μS cm⁻¹) -1 Four different flow rates (V) were further set. e =10, 25, 40 and 55mL min -1 The desalination performance of FCDI at different flow rates was tested.

[0112] like Figure 7 As shown, when V e Increase from 10 to 40 mL min -1 At that time, the effluent concentration (C / C0) of the HH-FCDI system continued to decrease, and the desalination parameters were significantly improved, and at V e =40mL min -1 At that time, SR, ASRR, and CE reached their highest values, at 77.34%, 12.03 μmol / cm, and 12.03 μmol / cm, respectively. -2 min -1 And 95.87%. The further improvement in the desalination performance of HH-FCDI indicates that the increased flow rate promotes the fluidity of the electrode slurry. Furthermore, with V... e Further increase (V) e =55mL min -1However, the desalination performance decreased accordingly, with SR, ASRR, and CE dropping to 71.14%, 11.27 μmol / cm³, and 11.27 μmol / cm³, respectively. -2 At 83.84%, excessively high flow rates will drastically increase pump energy consumption, which is not conducive to the practical application of the FCDI process. To pursue excellent desalination efficiencies (i.e., SR, ASRR, and CE), this study will adopt V... e =40mL min -1 Further experiments will be conducted.

[0113] Example 4

[0114] Set different salt solution concentrations (C0 = 5, 7.5, 10, and 20 g / L). -1 The desalination performance of the HH-FCDI system under different initial salt concentrations was tested. Ternary carbon composite material was used as the electrode slurry, in which the mass fraction of activated carbon was 12.5 wt.% and the mass fraction of carbon black + carbon nanotubes was 1.0 wt.%. Pulsed electric field parameters were set with a pulse frequency of 5 Hz, a duty cycle of 70%, and a pulse intensity of 90 mA.

[0115] like Figure 8 As shown, with the increase of the initial concentration, the effluent salt concentration change curve (C / C0) gradually flattens out, and correspondingly, the SR of the system continuously decreases, from 98.68 (5.0 g L / L). -1 The percentage dropped to 55.5% (10g L). -1 However, the ASRR increased significantly during the HH-FCDI process, rising from an initial 10.34 to 13.37 μmol cm⁻¹. -2 min -1 This indicates that increased salt ion concentration promotes ion migration and diffusion during FCDI. CO at higher concentrations (from 10 to 20 g / L) -1 The energy efficiency (CE) decreased from 97.25% to 82.15%, and the energy efficiency (ENRS) of the system decreased from 28.88% to 23.3 μmol J. -1 Based on comprehensive analysis and considering the negative impacts of excessively high salt concentrations, this study will select a concentration of C0 = 10 g / L. -1 Subsequent continuous desalination tests were conducted.

[0116] Example 5

[0117] Set the salt solution concentration C0 = 10 g / L -1The desalination performance of the HH-FCDI system under different initial salt concentrations was tested. A ternary carbon composite material was used as the electrode slurry, with activated carbon comprising 12.5 wt.% and carbon black + carbon nanotubes comprising 1.0 wt.%. Pulsed electric field parameters were set as follows: pulse frequency 5 Hz, duty cycle 70%, pulse intensity 90 mA, and electrode slurry flow rate 40 mL / min. -1 Furthermore, under the same conditions, RC-FCDI and SS-FCDI systems were set up for comparison.

[0118] like Figure 9-11 As shown, during the entire 1800-minute continuous operation of the RC-FCDI system, the effluent concentration variation (C / CO) exhibited a significant decrease, with the final SR and CE of the system being only 26.62% and 76.44%, respectively. Calculations showed that the average ASRR for the entire desalination process was 4.75 μmol / cm³. -2 min -1 Compared to RC-FCDI, the SS-FCDI system exhibits superior desalination performance, with a final SR of 50.71% and an average ASRR of 8.07 μmol / cm³. -2 min -1 Compared to RC-FCDI and SS-FCDI systems, the HH-FCDI system exhibits more efficient and stable desalination performance in continuous operation. Specifically, the effluent salt concentration variation (C / CO) remains consistently at 0.082, and the system's final SR reaches 91.87%, which is the purified brine concentration (C... s The blood glucose level decreased to 813.77 mg / L. -1 (Initial C) s =10000mg L -1 The average ASRR and CE for the entire run were 13.62 μmol cm⁻¹. -2 min -1 And 96.02%.

[0119] This invention further optimizes the flow efficiency of the electrode slurry by generating a dispersed flow field through a honeycomb flow channel, promotes charge conduction in the FCDI process, and thus achieves efficient and stable continuous operation of the HH-FCDI system.

[0120] The above technical solutions of the present invention are merely preferred embodiments of the present invention 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 present invention specification and drawings, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. Use of a flow electrode capacitive system in water treatment, characterized in that, The flow electrode capacitor system comprises a flow electrode capacitor device, a first delivery pump, a second delivery pump, a third delivery pump, an electrode slurry and a power supply; The first delivery pump and the first current collector constitute a first circulation channel, the second delivery pump and the second current collector constitute a second circulation channel, and the third delivery pump and the liquid inlet partition plate constitute a third circulation channel; The electrode slurry is located in the first circulation channel and the second circulation channel, and comprises activated carbon, carbon nanotubes, carbon black and sodium chloride, wherein the activated carbon accounts for 5-20% of the mass of the electrode slurry, the carbon nanotubes account for 0.1-1% of the mass of the electrode slurry, the carbon black accounts for 0.1-1% of the mass of the electrode slurry, and the sodium chloride accounts for 0.1-2% of the mass of the electrode slurry; The positive electrode of the power supply is connected with the first current collector, and the negative electrode is connected with the second current collector; The flow rate of the electrode slurry is 25 to 55 mL min -1 ; The flow electrode capacitor device comprises a first current collector, a cation exchange membrane, a liquid inlet partition plate, an anion exchange membrane and a second current collector arranged in sequence; The working surfaces of the first current collector and the second current collector are respectively provided with first flow channels and second flow channels, at least one of the first flow channels and the second flow channels is a mesh flow channel; the working surface is the surface of the first current collector and the second current collector facing the liquid inlet partition plate; The mesh flow channel comprises a plurality of mesh units, and in each mesh unit, the included angle between any two adjacent flow channel edges is greater than 90°, the depth of the flow channel edge is 1-3 mm, and the width of the flow channel edge is 1-4 mm; the total length of the mesh flow channel corresponds to 11.38-22.22% of the total area of the working surface; The application comprises: introducing the water to be treated into the solution cavity of the liquid inlet partition plate and circulating the flow through the third delivery pump; The electrode slurry is introduced into the first flow channel of the first current collector and circulated by the first delivery pump; The electrode slurry is introduced into the second flow channel of the second current collector and circulated by the second delivery pump; Desalination is performed by introducing a preset pulse electric field into the first current collector and the second current collector for 60-1800 min; The water to be treated is a salt solution, the concentration of the salt solution being 5 g L -1 ~20 g L -1 ; The pulse electric field parameters include: a pulse frequency of 5 Hz, a duty cycle of 70%, and a pulse intensity of 90 mA.

2. Use of the flow electrode capacitive system according to claim 1 in water treatment, characterized by, In the plurality of mesh units, at least part of the mesh units are the same, and the outlines of the mesh units are all regular polygons, and the number of sides of the regular polygons is 5-6.

3. Use of the flow electrode capacitive system according to claim 1 in water treatment, characterized by, The first flow channel and the second flow channel further comprise a flow channel frame, the mesh flow channel is arranged in an area surrounded by the flow channel frame, and is in communication with all the frame edges of the flow channel frame.

4. Use of a flow-through electrode capacitive system according to claim 3 in water treatment, characterized in that, The mesh units in a row close to the horizontal frame edge of the flow channel frame are in communication with the horizontal frame edge through the end portion; The mesh units in a column close to the vertical frame edge of the flow channel frame are in close communication with the vertical frame edge through the flow channel edge.

5. Use of a flow-through electrode capacitive system according to claim 4 in water treatment, characterized in that, The first current collector and the second current collector each comprise a liquid inlet and a liquid outlet in communication with the flow channel frame.

6. Use of a flow-through electrode capacitive system according to any one of claims 1 to 5 in water treatment, characterized in that, The depth of the solution cavity of the liquid inlet partition plate is 1-3 mm; The projections of the first flow channel and the second flow channel in the liquid inlet partition plate along the thickness direction of the flow electrode capacitor device are located in the solution cavity.

7. Use of a flow-through electrode capacitive system according to any one of claims 1 to 5 in water treatment, characterized in that, The flow electrode capacitor device further comprises two end plates, two flexible gaskets and a fastener, one of the end plates, one of the flexible gaskets, the first current collector, the cation exchange membrane, the liquid inlet separator, the anion exchange membrane, the second current collector, the other flexible gasket and the other end plate are sequentially arranged and fixed by the fastener.

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