A high-efficiency graded capacitor deionization device and wastewater treatment method

Abstract

The present invention relates to a high-efficiency graded capacitive deionization device and a wastewater treatment method. The high-efficiency graded capacitive deionization device comprises an insulating shell, wherein the cavity of the insulating shell is divided into at least a primary treatment area and a secondary treatment area along the direction of water flow; the primary treatment area is provided with a primary fixed electrode plate and a mesh plate, and the first channel between the primary fixed electrode plate and the mesh plate is filled with a mobile electrode; the secondary treatment area is provided with a secondary fixed electrode plate and a filter membrane, and a second channel is formed between the secondary fixed electrode plate and the filter membrane. The present invention also provides a wastewater treatment method based on the high-efficiency graded capacitive deionization device described in the present invention. The present invention solves the problems of low treatment efficiency and poor stability in the treatment of pickling wastewater by the existing capacitive deionization method.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a high-efficiency graded capacitor deionization device and a wastewater treatment method. Background Art

[0002] In the steel industry, in order to remove the oxide layer on the metal surface, inorganic acids such as sulfuric acid, phosphoric acid, nitric acid, and hydrofluoric acid are often used for pickling. This process produces a large amount of pickling wastewater, which is characterized by high acidity (pH about 1), large output (1-3 cubic meters of pickling wastewater may be generated for every ton of metal products pickled), and contains highly toxic metal ions such as Cr³⁺, Cr₃⁺, and Cr₃⁺ ... 6 ⁺, Ni²⁺, F⁻, etc. are included in the "National Hazardous Waste Catalogue" as hazardous wastes, classified as HW34 waste acid, and have a hazardous characteristic of T / C. According to the "Hazardous Waste Identification Standards," leachate pH ≤ 2 or any hazardous component exceeding the specified concentration limit is considered hazardous waste.

[0003] Traditional methods for treating pickling wastewater include neutralization, precipitation, crystallization, and membrane separation. However, these methods suffer from low efficiency, high costs, and secondary pollution. For example, neutralization involves adding alkaline substances to the wastewater to adjust the pH, causing metal ions to precipitate as hydroxides. However, this method often requires further treatment to meet discharge standards. While membrane separation technology can effectively separate ions, it is expensive to clean and replace the membranes, and is susceptible to contamination by particulate matter in the wastewater.

[0004] Capacitive deionization (CDI) is an emerging water treatment technology. Its basic principle is to force ions to migrate toward oppositely charged electrodes by applying an electrostatic field. The double layer generated at the interface between the electrodes and the electrolyte solution adsorbs and stores large quantities of electrolyte ions. This method is low-cost, highly efficient, and pollution-free, making it suitable for a variety of applications, including domestic and industrial water softening, wastewater purification, and seawater desalination. However, the complex quality of industrial wastewater in practice leads to low efficiency and poor stability in CDI treatment of pickling wastewater.

[0005] Therefore, reducing the concentration of toxic ions in pickling wastewater and converting it into ordinary waste is an effective way to render hazardous waste harmless and recycle it as a resource. However, while the cost of harmless treatment is high, pickling wastewater also contains high concentrations of strategic metal resources such as iron, chromium, and nickel, which have high recycling value. Therefore, effectively recovering the metals in pickling wastewater, taking into account its characteristics, is an urgent problem to be solved. Summary of the Invention

[0006] In view of this, the object of the present invention is to provide a high-efficiency graded capacitive deionization device and a wastewater treatment method to solve the problems of low treatment efficiency and poor stability in the existing capacitive deionization method for treating pickling wastewater.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A high-efficiency graded capacitive deionization device comprises an insulating shell, wherein the cavity of the insulating shell is divided into at least a primary treatment area and a secondary treatment area along the direction of water flow;

[0009] The primary treatment area is provided with a primary fixed electrode plate and a mesh plate, and the first channel between the primary fixed electrode plate and the mesh plate is filled with a flow electrode;

[0010] The secondary treatment area is provided with a secondary fixed electrode plate and a filter membrane, and a second channel is formed between the secondary fixed electrode plate and the filter membrane;

[0011] When treating wastewater, the pollutants in the wastewater are removed by the combination of the first-level fixed electrode plate and the flow electrode. The qualified wastewater treated in the first-level treatment area is discharged, and the unqualified wastewater flows into the second channel together with the flow electrode, and the deep removal of pollutants in the wastewater is achieved by the combination of the second-level fixed electrode plate and the flow electrode.

[0012] Preferably, the flow electrode is made of a mixture of foamed nickel, graphene and polyvinylidene fluoride.

[0013] Preferably, the preparation method of the mobile electrode comprises:

[0014] The nickel foam, graphene and polyvinylidene fluoride are mixed, an organic solvent is added, the mixture is formed, and the mixture is dried to obtain a mobile electrode.

[0015] Preferably, the mass ratio of the nickel foam, graphene and polyvinylidene fluoride is 8:1:1.

[0016] Preferably, the drying method is: drying at a temperature of 120° C. for 2 hours, and then drying at a temperature of 80° C. for 2 hours.

[0017] Preferably, the organic solvent is selected from N,N-dimethylacetamide.

[0018] Preferably, the flow electrode is a spherical electrode.

[0019] The spherical electrode is prepared by mixing nickel foam, graphene, and polyvinylidene fluoride in a mass ratio of 8:1:1, using N,N-dimethylacetamide as the solvent. An appropriate amount of solvent is added to form the mixture into a clay-like consistency. The mixture is then shaped into small balls to obtain the spherical electrode. The mixture is then dried at 120°C for 2 hours and then in a vacuum oven at 80°C for 2 hours to remove all organic solvent. The spherical electrode is then removed. This preparation method improves the electrode's fluidity, enabling convenient replacement after adsorption saturation and facilitating optimization of electrode shape. This facilitates uniform electrode distribution within the device and increases contact area with the reaction medium, thereby improving overall device performance. Compared to conventional nickel foam electrodes, this method enhances the electrode's conductivity through the addition of graphene. The mechanical properties of the spherical electrode are enhanced through the bonding of polyvinylidene fluoride, potentially resulting in improved toughness and strength, ensuring stability during repeated use. Furthermore, the addition of graphene to the nickel foam enhances the adsorption capacity of target substances, thereby extending the electrode's service life.

[0020] Preferably, at least two of the primary fixed electrode plates are provided in the primary processing area near the cavity wall, and at least two of the mesh plates are provided near the cavity center;

[0021] The primary treatment area is divided into at least two of the first channels and at least one third channel by the primary fixed electrode plate and the mesh plate. When treating wastewater, voltages of opposite polarity are applied to at least two of the primary fixed electrode plates. Through the combination of the primary fixed electrode plates and the flow electrodes, the pollutants in the wastewater move to the primary fixed electrode plates and the flow electrodes with opposite polarity and are adsorbed, so as to simultaneously achieve the removal of pollutants of different polarities in the wastewater.

[0022] Preferably, at least two of the secondary fixed electrode plates are provided in the secondary treatment area near the cavity wall, and the filter membrane is provided near the center of the cavity. The secondary treatment area is divided into two second channels by the filter membrane, so that the substandard wastewater and the flow electrode are diverted into the second channel, and voltages of opposite polarity are applied to at least two of the secondary fixed electrode plates. Through the combination of the secondary fixed electrode plates and the flow electrodes, the remaining pollutants in the wastewater continue to move toward the secondary fixed electrode plates and the flow electrodes with opposite polarity and are adsorbed, so as to simultaneously achieve deep removal of residual pollutants of different polarities in the wastewater.

[0023] Preferably, a material adding area connected to the first channel of the primary processing area is provided in the cavity of the insulating shell at the top of the primary processing area, and the material adding area is used to accommodate the flow electrode.

[0024] Preferably, the feeding area is designed with an opening for easy filling and observation.

[0025] Preferably, a wastewater inlet and a primary water outlet are provided on the insulating shell located in the third channel.

[0026] Among them, a water inlet pipe is arranged on the insulating shell located in the third channel, and multiple wastewater inlets are evenly spaced on the water inlet pipe to achieve wastewater diversion, ensure that the wastewater is in full contact with the mobile electrode and the fixed electrode plate, and improve deionization efficiency.

[0027] Preferably, a secondary water outlet and a flow electrode outlet are provided on the insulating shell located in the second channel.

[0028] Preferably, a pressing device is provided in the first channel, and the flow of the flow electrode is achieved by pressing the pressing device.

[0029] Preferably, an insulating baffle is provided between the feeding area and the third channel of the primary processing area.

[0030] By arranging an insulating baffle between the feeding area and the third channel, direct contact of the current is effectively prevented, ensuring safe operation.

[0031] Preferably, a first insulating elastic rubber and a second insulating elastic rubber are provided between the primary treatment area and the secondary treatment area, and the pressing device is pressed so that the flow electrode and the substandard wastewater squeeze the first insulating elastic rubber and the second insulating elastic rubber, so that the first insulating elastic rubber and the second insulating elastic rubber are separated to form a channel for the flow electrode and the substandard wastewater to flow through.

[0032] By providing a first insulating elastic rubber and a second insulating elastic rubber offsetting each other between the primary and secondary treatment zones, the flow electrodes and wastewater are effectively connected, while also preventing direct contact between the primary and secondary treatment zones, ensuring that the treatment efficiency of the two zones is not affected. The insulating elastic rubber is highly elastic and chemically resistant.

[0033] Preferably, the primary fixed electrode plate and the secondary fixed electrode plate are made of corrosion-resistant materials to enhance the deionization effect and improve the processing efficiency.

[0034] Preferably, the exterior of the insulating housing is designed with a handle for easy transportation and installation, and a mounting hole for fixing the device, to ensure the stability of the device and facilitate mobility.

[0035] Preferably, the surfaces of the primary fixed electrode plate and the secondary fixed electrode plate are designed with protruding structures that increase the contact area to improve the electric field strength and deionization efficiency, and the shape and size of the protruding structures are optimized.

[0036] Preferably, the pore size and distribution of the mesh plate are precisely calculated to ensure uniform flow of the flow electrodes and sufficient contact of the wastewater, thereby improving deionization efficiency.

[0037] Preferably, the filter membrane is made of a highly permeable material to ensure smooth water flow in the secondary treatment area while effectively removing residual tiny particles.

[0038] Preferably, the high-efficiency graded capacitive deionization device further includes sensors and controllers for monitoring and controlling the treatment process, such as a pH sensor, a conductivity sensor and a temperature sensor, and corresponding control circuits, to achieve automation and optimization of the treatment process.

[0039] The present invention also provides a wastewater treatment method based on the high-efficiency graded capacitive deionization device of the present invention, comprising the following steps:

[0040] The flow electrode is placed in the feeding area, and the flow electrode is pressed by a pressing device to flow into the first channel of the primary treatment area;

[0041] Wastewater flows into the primary treatment area through the wastewater inlet, and voltages of opposite polarity are applied to at least two primary fixed electrode plates. Through the combination of the primary fixed electrode plates and the flow electrodes, pollutants in the wastewater move to the primary fixed electrode plates and the flow electrodes with opposite polarity and are adsorbed, thereby simultaneously removing pollutants of different polarities in the wastewater. The wastewater that meets the standards after being treated in the primary treatment area is discharged from the primary outlet.

[0042] The substandard wastewater and the flow electrode flow into the second channel respectively, and voltages of opposite polarity are applied to at least two of the secondary fixed electrode plates. Through the combination of the secondary fixed electrode plates and the flow electrodes, the remaining pollutants in the wastewater continue to move toward the secondary fixed electrode plates and the flow electrodes with opposite polarity and are adsorbed, so as to simultaneously achieve deep removal of residual pollutants of different polarities in the wastewater. The qualified wastewater after treatment in the secondary treatment area is discharged from the secondary outlet, and the flow electrodes that adsorb pollutants flow out from the flow electrode outlet.

[0043] Preferably, the voltage applied to the secondary treatment zone is greater than the voltage applied to the primary treatment zone.

[0044] Preferably, it also includes regeneration of the primary fixed electrode plate, the flow electrode and the secondary fixed electrode plate. The regeneration method is to connect the primary fixed electrode plate to a voltage with a polarity opposite to that when the primary fixed electrode plate treats wastewater, connect the flow electrode to a voltage with a polarity opposite to that when the primary fixed electrode plate treats wastewater, and connect the secondary fixed electrode plate to a voltage with a polarity opposite to that when the secondary fixed electrode plate treats wastewater, thereby achieving regeneration of the primary fixed electrode plate, the flow electrode and the secondary fixed electrode plate. The regenerated primary fixed electrode plate, the flow electrode and the secondary fixed electrode plate can be recycled for treating acidic wastewater.

[0045] Beneficial effects of the present invention:

[0046] The high-efficiency graded capacitive deionization device of the present invention adopts a multi-stage treatment structure. The wastewater first undergoes preliminary ion removal in the primary treatment area and then undergoes deep treatment in the secondary treatment area. This graded treatment method not only improves the ion removal rate, but also achieves efficient and selective removal of different ions by optimizing the electrode configuration and filler channel design of each stage of treatment area. Compared with traditional single-stage treatment, the multi-stage treatment structure of the present invention can more effectively deal with the various ions in complex wastewater, providing a more stable and continuous treatment effect, especially when treating high-concentration, multi-component pickling wastewater.

[0047] The high-efficiency graded capacitive deionization device of the present invention, the mobile electrode, achieves effective adsorption and enrichment of ions by adding a mobile electrode that can flow between the electrode and the perforated mesh plate. The addition of the mobile electrode eliminates the need for traditional ion exchange membranes or reverse osmosis membranes, reduces costs, and avoids the problems of membrane contamination and replacement. The design of the mobile electrode allows ions to migrate to the electrode surface more quickly under the action of the electric field, thereby improving the processing speed and efficiency. In addition, due to the reproducibility and reusability of the filler, the device of the present invention has lower maintenance costs and is easier to operate during long-term use, and there is no additional environmental burden caused by membrane replacement. In the field of wastewater treatment technology, it has promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a structural schematic diagram of a high-efficiency graded capacitive deionization device;

[0049] Figure 2 This is a front view of a high-efficiency graded capacitive deionization device;

[0050] Figure 3 for Figure 2 Cross-sectional view along the middle line AA;

[0051] Figure 4 for Figure 2 Cross-sectional view along the middle edge BB;

[0052] Figure 5This is a comparison chart of the removal effects of calcium in acidic wastewater by a high-efficiency graded capacitive deionization device and a common capacitive deionization device;

[0053] Figure 6 This is a comparison chart of the removal effects of high-efficiency graded capacitive deionization devices and ordinary capacitive deionization devices on iron in acidic wastewater;

[0054] Figure 7 This is a comparison chart of the removal effects of fluoride in acidic wastewater by a high-efficiency graded capacitive deionization device and a common capacitive deionization device;

[0055] Figure 8 This is a comparison chart of the removal effects of chromium in acidic wastewater by a high-efficiency graded capacitive deionization device and a conventional capacitive deionization device;

[0056] Figure 9 This is a comparison chart of pH before and after treating acidic wastewater using a high-efficiency graded capacitive deionization device and a conventional capacitive deionization device;

[0057] Figure 10 This is a comparison chart of the conductivity of acidic wastewater treated by a high-efficiency graded capacitive deionization device and a conventional capacitive deionization device;

[0058] Figure 11 It is a structural diagram of a common capacitive deionization device;

[0059] Among them, 1-insulating shell, 11-primary treatment area, 111-first channel, 112-third channel, 113-wastewater inlet, 114-primary outlet, 12-secondary treatment area, 121-second channel, 122-secondary outlet, 123-flow electrode outlet; 2-primary fixed electrode plate; 3-mesh plate; 4-flow electrode; 5-secondary fixed electrode plate; 6-filter membrane; 7-feeding area, 71-feeding port; 8-pressing device; 9-insulating baffle; 10-first insulating elastic rubber; 13-second insulating elastic rubber;

[0060] 01-screw; 02-acrylic fixing plate; 03-first silicone pad; 04-positive electrode current collector; 05-second silicone pad; 06-acrylic plate; 07-negative electrode current collector. DETAILED DESCRIPTION

[0061] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0062] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0063] The present invention aims to provide a high-efficiency graded capacitive deionization device to solve the problems of high pH value limit, large iron sludge production and difficulty in subsequent treatment in the existing wastewater treatment combined with ultrasound and Fenton.

[0064] Among them, Figures 1 to 4 As shown, a high-efficiency graded capacitive deionization device includes an insulating shell 1, wherein the cavity of the insulating shell 1 is divided into at least a primary treatment area 11 and a secondary treatment area 12 along the water flow direction;

[0065] The primary treatment area 11 is provided with a primary fixed electrode plate 2 and a mesh plate 3, and the first channel 111 between the primary fixed electrode plate 2 and the mesh plate 3 is filled with a mobile electrode 4;

[0066] The secondary treatment area 12 is provided with a secondary fixed electrode plate 5 and a filter membrane 6, and a second channel 121 is formed between the secondary fixed electrode plate 5 and the filter membrane 6;

[0067] When treating wastewater, pollutants in the wastewater are removed by combining the primary fixed electrode plate 2 and the mobile electrode 4. The qualified wastewater treated in the primary treatment area 11 is discharged, and the unqualified wastewater flows into the second channel 121 together with the mobile electrode 4, and the deep removal of pollutants in the wastewater is achieved by combining the secondary fixed electrode plate 5 and the mobile electrode 4.

[0068] In some embodiments, the flow electrode 4 is made of a mixture of foamed nickel, graphene, and polyvinylidene fluoride.

[0069] In some embodiments, the preparation method of the mobile electrode 4 includes:

[0070] The nickel foam, graphene and polyvinylidene fluoride are mixed, an organic solvent is added, the mixture is formed, and the mixture is dried to obtain a mobile electrode.

[0071] Exemplarily, the mass ratio of nickel foam, graphene and polyvinylidene fluoride is 8:1:1.

[0072] Exemplarily, the drying method is: drying at a temperature of 120° C. for 2 hours, and then drying at a temperature of 80° C. for 2 hours;

[0073] Exemplarily, the organic solvent is selected from N,N-dimethylacetamide.

[0074] Exemplarily, the flow electrode 4 is a spherical electrode;

[0075] In some embodiments, at least two primary fixed electrode plates 2 are provided in the primary processing area 11 near the cavity wall, and at least two mesh plates 3 are provided near the cavity center.

[0076] The primary treatment area 11 is divided into at least two first channels 111 and at least one third channel 112 by the primary fixed electrode plate 2 and the mesh plate 3. When treating wastewater, voltages of opposite polarity are applied to at least two of the primary fixed electrode plates 2. Through the combination of the primary fixed electrode plate 2 and the flow electrode 4, the pollutants in the wastewater move to the primary fixed electrode plate 2 and the flow electrode 4 with opposite polarity and are adsorbed, so as to simultaneously achieve the removal of pollutants of different polarities in the wastewater.

[0077] In some embodiments, at least two of the secondary fixed electrode plates 5 are provided near the cavity wall of the secondary treatment area 12, and the filter membrane 6 is provided near the center of the cavity. The filter membrane 6 separates the secondary treatment area 12 into two second channels 121, so that substandard wastewater and the flow electrode 4 are diverted into the second channels 121, and voltages of opposite polarity are applied to the at least two secondary fixed electrode plates 5. Through the combination of the secondary fixed electrode plates 5 and the flow electrode 4, the remaining pollutants in the wastewater continue to move toward the secondary fixed electrode plates 5 and the flow electrode 4 of opposite polarity and are adsorbed, thereby simultaneously achieving deep removal of residual pollutants of different polarities in the wastewater.

[0078] In some embodiments, a feeding area 7 is provided within the cavity of the insulating housing 1 at the top of the primary processing area 11, connected to the first channel 111 of the primary processing area 11. The feeding area 7 is used to accommodate the mobile electrode 4. A feeding port 71 is provided on the insulating housing 1 at a location corresponding to the feeding area 7.

[0079] Exemplarily, the insulating housing 1 located in the third channel 112 is provided with a wastewater inlet 113 and a primary outlet 114. The insulating housing 1 located in the second channel 121 is provided with a secondary outlet 122 and a flow electrode outlet 123 to facilitate the recovery of the flow electrode. The bottom of the second channel 121 is inclined, with the bottom of the secondary outlet 122 higher than the bottom of the flow electrode outlet 123, allowing the flow electrode 4 to flow out of the flow electrode outlet 123 more efficiently.

[0080] In some embodiments, a pressing device 8 is provided in the first channel 111 , and the flow of the flow electrode 4 is achieved by pressing the pressing device 8 ;

[0081] In some embodiments, in order to prevent direct contact of electric current and ensure operational safety, an insulating baffle 9 is provided between the feeding area 7 and the third channel 112 of the primary processing area 11 .

[0082] In some embodiments, in order to achieve smooth flow of the flow electrode and wastewater, and at the same time prevent direct contact between the current of the primary treatment area and the secondary treatment area, and avoid mutual influence between the treatment efficiency of the primary treatment area and the secondary treatment area, a first insulating elastic rubber 10 and a second insulating elastic rubber 13 are offset between the primary treatment area 11 and the secondary treatment area 12. When the pressing device 8 is pressed, the flow electrode 4 and the substandard wastewater squeeze the first insulating elastic rubber 10 and the second insulating elastic rubber 13, so that the first insulating elastic rubber 10 and the second insulating elastic rubber 13 are separated to form a channel for the flow electrode 4 and the substandard wastewater to flow through.

[0083] In some embodiments, a wastewater treatment method based on the above-mentioned high-efficiency graded capacitive deionization device is further provided, comprising the following steps:

[0084] The flow electrode 4 is placed in the feeding area 7 and is pressed by the pressing device 8 to flow into the first channel 111 of the primary treatment area 11;

[0085] Wastewater flows into the primary treatment area 11 through the wastewater inlet 113. Voltages of opposite polarity are applied to at least two primary fixed electrode plates 2. The combination of the primary fixed electrode plates 2 and the mobile electrodes 4 causes pollutants in the wastewater to move toward the primary fixed electrode plates 2 and the mobile electrodes 4 of opposite polarity and be adsorbed, thereby simultaneously removing pollutants of different polarities from the wastewater. The qualified wastewater treated in the primary treatment area 11 is discharged from the primary outlet 114.

[0086] The substandard wastewater and the flow electrode 4 flow into the second channel 121 respectively, and voltages of opposite polarity are applied to at least two secondary fixed electrode plates 5. Through the combination of the secondary fixed electrode plates 5 and the flow electrode 4, the remaining pollutants in the wastewater continue to move toward the secondary fixed electrode plates 5 and the flow electrode 4 with opposite polarity and are adsorbed, so as to simultaneously achieve deep removal of residual pollutants of different polarities in the wastewater. The qualified wastewater treated in the secondary treatment area 12 is discharged from the secondary water outlet 122, and the flow electrode 4 that adsorbs pollutants flows out from the flow electrode outlet 123.

[0087] In some embodiments, the voltage applied to the secondary treatment region 12 is greater than the voltage applied to the primary treatment region 11 .

[0088] In order to make the technical problems, technical solutions and beneficial effects solved by this application clearer, the high-efficiency graded capacitor deionization device of the present invention and its method for treating wastewater will be further described in detail below in conjunction with some specific embodiments and drawings. Obviously, the specific embodiments described are only part of the embodiments of this application, not all of them. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications. Based on the specific embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0089] Example 1

[0090] like Figures 1 to 4 As shown, a high-efficiency graded capacitive deionization device includes an insulating housing 1. The cavity of the insulating housing 1 is rectangular in structure. The cavity of the insulating housing 1 is divided into a primary treatment area 11 and a secondary treatment area 12 along the water flow direction (i.e., the length direction) by a first insulating elastic rubber 10 and a second insulating elastic rubber 13 that offset each other.

[0091] Two primary fixed electrode plates 2 are provided opposite to each other along the width direction of the cavity wall of the primary processing area 11, and two mesh plates 3 are provided at intervals near the center of the cavity, so that one of the primary fixed electrode plates 2 and one of the mesh plates 3 form a first channel 111, the two mesh plates 3 form a third channel 112, and the other mesh plate 3 and the other fixed electrode plate 2 form another first channel 111. The two first channels 111 are both equipped with flow electrodes 4;

[0092] Two secondary fixed electrode plates 5 are disposed opposite each other near the cavity wall in the width direction of the secondary processing zone 12, and a filter membrane 6 is disposed near the center of the cavity. One of the secondary fixed electrode plates 5 and the filter membrane 6 forms a second channel 121, and the filter membrane 6 and the other secondary fixed electrode plate 5 form another second channel 121.

[0093] A feeding area 7 is provided in the cavity of the insulating housing 1 at the top of the primary processing area 11 and is connected to the first channel 111 of the primary processing area 11. The feeding area 7 is used to accommodate the mobile electrode 4.

[0094] A pressing device 8 is provided in the first channel 111 , and the flow of the flow electrode 4 is achieved by pressing the pressing device 8 ;

[0095] A wastewater inlet 113 is provided on the insulating housing 1 located near the bottom of the third channel 112, and a first-level water outlet 114 is provided on the insulating housing 1 near the top;

[0096] A secondary water outlet 122 and a flow electrode outlet 123 are respectively provided on the insulating housing 1 on opposite sides of the second channel 121 and near the bottom. The bottom of the second channel 121 is an inclined surface, and the bottom of the secondary water outlet 122 is higher than the bottom of the flow electrode outlet 123.

[0097] An insulating baffle 9 is provided between the feeding area 7 and the third channel 112 of the primary processing area 11;

[0098] The volume of the primary treatment area 11 is approximately 640 ml, and the volume of the secondary treatment area 12 is approximately 380 ml;

[0099] The preparation method of the mobile electrode 4 includes:

[0100] Nickel foam, graphene, and polyvinylidene fluoride were uniformly mixed in a mass ratio of 8:1:1. An appropriate amount of N,N-dimethylacetamide was then added to form the mixture into a clay-like consistency. An appropriate amount of the mixture was then molded into small balls to form a spherical electrode. The spherical electrode was then dried at 120°C for 2 hours and then in a vacuum drying oven at 80°C for 2 hours to remove all organic solvent. This resulted in a spherical flow electrode 4.

[0101] Example 2

[0102] Taking the pickling wastewater treatment sample of a steel plant in Jiangsu Province as an example, the main ion composition of the pickling wastewater treatment sample and the pH and conductivity data of the wastewater are shown in Table 1.

[0103] Table 1 shows the ion content, pH and conductivity data of the pickling wastewater treatment samples

[0104]

[0105] The acid wastewater treatment sample is 2 L, and the method for treating the acid wastewater using the high-efficiency graded capacitive deionization device in Example 1 comprises the following steps:

[0106] S1, loading the flow electrode 4 into the feeding area 7 from the feeding port 71, and pressing the pressing device 8 to make the flow electrode 4 flow into the two first channels 111 of the primary treatment area 11;

[0107] S2. Wastewater is flowed into the primary treatment zone 11 through the wastewater inlet 113 at a flow rate of 10 ml / min. A voltage of 2 V with opposite polarity is applied to the two primary fixed electrode plates 2. Through the combination of the primary fixed electrode plates 2 and the mobile electrodes 4, pollutants in the wastewater move to the primary fixed electrode plates 2 and the mobile electrodes 4 with opposite polarity and are adsorbed, thereby simultaneously removing pollutants of different polarities from the wastewater. The qualified wastewater treated in the primary treatment zone 11 is discharged from the primary outlet 114.

[0108] S3, pressing the pressing device 8, so that the flow electrode 4 and the substandard wastewater squeeze the first insulating elastic rubber 10 and the second insulating elastic rubber 13, so that the first insulating elastic rubber 10 and the second insulating elastic rubber 13 are separated to form a channel for the flow electrode 4 and the substandard wastewater to flow into the second channel 121;

[0109] S4. Apply a 3V voltage of opposite polarity to the two secondary fixed electrode plates 5 in the secondary treatment area 12. Through the combination of the secondary fixed electrode plates 5 and the flow electrode 4, the remaining pollutants in the substandard wastewater flowing into the second channel 121 continue to move toward the secondary fixed electrode plates 5 and the flow electrode 4 with opposite polarity and are adsorbed, so as to simultaneously achieve deep removal of residual pollutants of different polarities in the wastewater. The qualified wastewater treated in the secondary treatment area 12 is discharged from the secondary water outlet 122, and the flow electrode 4 that adsorbs pollutants flows out from the flow electrode outlet 123.

[0110] Comparative Example 1

[0111] Using a common capacitor deionization device purchased on the market, the two use the same electrodes and the same wastewater flow rate. The treatment effects are compared. Figures 4 to 10 As shown, the process exhibits a distinct exponential change, with a sharp initial change followed by a gradual gradual change. The concentrations of various ions decrease significantly during the treatment process. Comparing the performance of the high-performance graded capacitive deionization device with that of a commercially available standard capacitive deionization device reveals that the high-performance graded capacitive deionization device is significantly more effective in removing complex ions, achieving removal rates of 85% to 95% across all indicators, meeting expectations.

[0112] Among them, such as Figure 11 As shown, the ordinary capacitive deionization device purchased on the market includes, from left to right, an acrylic fixing plate 02, a first silicone pad 03, a positive electrode current collector 04, a second silicone pad 05, an acrylic plate 06 for wastewater to flow through, a second silicone pad 05, a negative electrode current collector 07, a first silicone pad 03 and an acrylic fixing plate 02. The acrylic fixing plate 02, the first silicone pad 03, the positive electrode current collector 04, the second silicone pad 05, the acrylic plate 06 for wastewater to flow through, the second silicone pad 05, the negative electrode current collector 07, the first silicone pad 03 and the acrylic fixing plate 02 are connected and fixed by screws 01.

[0113] In summary, the device of the present invention, firstly, through the innovative hierarchical treatment and flow electrode concepts, can achieve efficient deionization treatment without a membrane. This design not only improves the treatment efficiency, but also reduces energy consumption, effectively addressing the problem of water pollution. The design of the hierarchical treatment structure enables the device to more effectively remove multiple ions in water, especially when treating complex wastewater containing multiple metal ions and non-metallic ions, and can provide a more stable and continuous treatment effect. Secondly, the device of the present invention adopts a multi-stage treatment structure, and the wastewater is first subjected to preliminary ion removal in the primary treatment area, and then deep treatment is carried out in the secondary treatment area. This hierarchical treatment method not only improves the ion removal rate, but also achieves efficient and selective removal of different ions by optimizing the electrode configuration and filler channel design of each stage of treatment area. Compared with traditional single-stage treatment, the multi-stage treatment structure of the present invention can more effectively deal with multiple ions in complex wastewater, provide a more stable and continuous treatment effect, and is particularly outstanding when treating high-concentration, multi-component pickling wastewater. Thirdly, the flow electrode design of the device of the present invention allows ions to migrate to the electrode surface more quickly under the action of the electric field, thereby improving the treatment speed and efficiency. In addition, due to the renewability and reusability of the filler, the device of the present invention has lower maintenance costs and is easier to operate during long-term use, and there is no additional environmental burden caused by membrane replacement. This design does not require traditional ion exchange membranes or reverse osmosis membranes, which reduces costs and avoids the problems of membrane contamination and replacement, making the operation of the device more economical and environmentally friendly. Fourthly, the device of the present invention has a compact structure, is easy to operate, and has low maintenance costs: the design of the device of the present invention focuses on practicality and easy maintenance. The compact structure not only reduces the occupied space but also simplifies the operation process. The easy operation allows non-professionals to quickly master the usage skills, reducing dependence on professional operators. The maintenance cost is low. Due to the use of a flow electrode design that does not require a membrane, frequent replacement and cleaning of the membrane is avoided, reducing maintenance costs and environmental burden. These designs make the device of the present invention more economical and convenient in practical applications. The device of the present invention is suitable for ion removal needs under various water quality conditions, especially continuous operation and water containing multiple types of heavy metals: the design of the device of the present invention fully considers the diversity and complexity of practical applications. The device is suitable for ion removal in various water quality conditions, providing stable and efficient treatment results, whether in continuous operation or in conditions involving water containing multiple heavy metals. This wide applicability enables the device to meet the needs of various industries and scenarios, and has high practical value and market potential, making it valuable for widespread application in the field of wastewater treatment technology.

[0114] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A high-efficiency graded capacitive deionization device, characterized in that: It comprises an insulating shell (1), wherein the cavity of the insulating shell (1) is divided into at least a primary treatment area (11) and a secondary treatment area (12) along the water flow direction; At least two primary fixed electrode plates (2) are provided in the primary processing area (11) near the cavity wall, and at least two mesh plates (3) are provided near the center of the cavity; The primary processing area (11) is divided into at least two first channels (111) and at least one third channel (112) by the primary fixed electrode plate (2) and the mesh plate (3); the first channel (111) between the primary fixed electrode plate (2) and the mesh plate (3) is filled with a flow electrode (4); At least two secondary fixed electrode plates (5) are provided in the secondary treatment area (12) near the cavity wall, and a filter membrane (6) is provided near the center of the cavity. The secondary treatment area (12) is divided into two second channels (121) by the filter membrane (6), and a second channel (121) is formed between the secondary fixed electrode plates (5) and the filter membrane (6); a wastewater inlet (113) and a primary water outlet (114) are provided on the insulating housing (1) located in the third channel (112); a pressing device (8) is provided in the first channel (111) ), the flow of the flow electrode (4) is achieved by pressing the pressing device (8); a first insulating elastic rubber (10) and a second insulating elastic rubber (3) are provided between the primary treatment area (11) and the secondary treatment area (12), and the pressing device (8) is pressed so that the flow electrode (4) and the substandard wastewater squeeze the first insulating elastic rubber (10) and the second insulating elastic rubber (3), so that the first insulating elastic rubber (10) and the second insulating elastic rubber (3) are separated to form a channel for the flow electrode (4) and the substandard wastewater to flow through; When treating wastewater, pollutants in the wastewater are removed by combining the primary fixed electrode plate (2) and the mobile electrode (4). The wastewater that meets the standards after being treated in the primary treatment area (11) is discharged, and the wastewater that does not meet the standards flows into the second channel (121) together with the mobile electrode (4). The pollutants in the wastewater are deeply removed by combining the secondary fixed electrode plate (5) and the mobile electrode (4).

2. The high-efficiency graded capacitive deionization device according to claim 1, characterized in that: The flow electrode (4) is made of a mixture of foamed nickel, graphene and polyvinylidene fluoride.

3. The high-efficiency graded capacitive deionization device according to claim 2, characterized in that: The preparation method of the mobile electrode (4) comprises: The nickel foam, graphene and polyvinylidene fluoride are mixed, an organic solvent is added, the mixture is formed, and the mixture is dried to obtain a mobile electrode.

4. The high-efficiency graded capacitive deionization device according to claim 3, characterized in that: The mass ratio of the nickel foam, graphene and polyvinylidene fluoride is 8:1:1; And / or, the drying method is: drying at a temperature of 120° C. for 2 hours, and then drying at a temperature of 80° C. for 2 hours; And / or, the organic solvent is selected from N,N-dimethylacetamide.

5. The high-efficiency graded capacitive deionization device according to claim 1, characterized in that: The flow electrode (4) is a spherical electrode; And / or, a feeding area (7) connected to the first channel (111) of the primary processing area (11) is provided in the cavity of the insulating shell (1) at the top of the primary processing area (11), and the feeding area (7) is used to install the flow electrode (4).

6. The high-efficiency graded capacitive deionization device according to claim 5, characterized in that: A secondary water outlet (122) and a flow electrode outlet (123) are provided on the insulating housing (1) located in the second channel (121).

7. The high-efficiency graded capacitive deionization device according to claim 5, characterized in that: An insulating baffle (9) is provided between the feeding area (7) and the third channel (112) of the primary processing area (11).

8. A wastewater treatment method based on the high-efficiency graded capacitive deionization device according to any one of claims 1 to 7, characterized in that: The following steps are involved: The flow electrode (4) is loaded into the feeding area (7), and the flow electrode (4) is pressed by the pressing device (8) to flow into the first channel (111) of the primary treatment area (11); Wastewater flows into the primary treatment area (11) through the wastewater inlet (113), and voltages of opposite polarity are applied to at least two primary fixed electrode plates (2). Through the combination of the primary fixed electrode plates (2) and the flow electrodes (4), pollutants in the wastewater move to the primary fixed electrode plates (2) and the flow electrodes (4) of opposite polarity and are adsorbed, thereby simultaneously achieving the removal of pollutants of different polarities in the wastewater. The wastewater that meets the standards after being treated in the primary treatment area (11) is discharged from the primary water outlet (114); The pressing device is used to make the wastewater that does not meet the standards and the flow electrode (4) flow into the second channel (121) respectively, and voltages of opposite polarity are applied to at least two of the secondary fixed electrode plates (5). Through the combination of the secondary fixed electrode plates (5) and the flow electrode (4), the remaining pollutants in the wastewater continue to move to the secondary fixed electrode plates (5) and the flow electrode (4) of opposite polarity and are adsorbed, so as to simultaneously achieve deep removal of residual pollutants of different polarities in the wastewater. The wastewater that meets the standards after being treated in the secondary treatment area (12) is discharged from the secondary water outlet (122), and the flow electrode (4) that adsorbs pollutants flows out from the flow electrode outlet (123).

9. The wastewater treatment method according to claim 8, characterized in that: The voltage applied to the secondary treatment area (12) is greater than the voltage applied to the primary treatment area (11).

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