Electrochemical oxidation and capacitive deionization coupled water treatment system and method

Abstract

The invention discloses an electrochemical oxidation and capacitive deionization coupled water treatment system and method, and belongs to the technical field of wastewater treatment. The method comprises the following steps: introducing wastewater to be treated into an electrochemical oxidation unit for oxidation so as to oxidize nonionic organic pollutants into an ionizable organic intermediate product, introducing the oxidized wastewater into a capacitive deionization unit for adsorption, and simultaneously adsorbing inorganic salt ions and the organic intermediate product by using the capacitive deionization unit. According to the method disclosed by the invention, synchronous removal of COD and salinity is realized through an ionization-adsorption synergistic mechanism. The method is suitable for wide types of organic wastewater and has excellent universality and popularization value, the overall energy consumption required by treatment is remarkably reduced, the problem that the energy consumption of a traditional electrochemical oxidation process is relatively high is effectively relieved, and the engineering application economy of the process is improved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a water treatment system and method coupled with electrochemical oxidation and capacitive deionization. Background Technology

[0002] High-salinity, recalcitrant organic wastewater poses a significant environmental challenge to the industrial sector. This type of wastewater contains both high concentrations of inorganic salts and persistent organic pollutants harmful to the environment. Traditional physicochemical or biological treatment methods often struggle to simultaneously address desalination and organic matter removal, or are ineffective due to the high-salinity environment inhibiting microbial activity.

[0003] To address this challenge, advanced electrochemical oxidation (EO) technologies, particularly electrochemical oxidation (EO), have attracted attention due to their ability to generate highly oxidizing reactive species such as hydroxyl radicals (·OH), which can effectively degrade and even mineralize various recalcitrant organic compounds. However, single EO processes have two inherent drawbacks: first, they cannot remove inorganic salts from wastewater; second, achieving complete mineralization of organic matter into carbon dioxide and water requires extremely high energy input, resulting in high treatment costs and limiting their large-scale application.

[0004] Meanwhile, capacitive deionization (CDI), as an emerging electro-adsorption desalination technology, has shown great potential in the field of water treatment due to its advantages such as low energy consumption, environmental friendliness, and no need for chemical regeneration. CDI technology achieves desalination by forming an electric double layer on the electrode surface to efficiently adsorb dissolved ions in water. However, the limitations of traditional CDI technology are also quite obvious: it is mainly effective for ionic substances, and has virtually no ability to remove non-ionizable, non-polar small organic molecules in water. Furthermore, the electrodes are easily contaminated by organic matter, leading to performance degradation.

[0005] Given the functional complementarity of EO and CDI technologies, existing technologies have explored combining them in series. For example, Chinese patent CN106006860A discloses a solar-powered high-salt organic wastewater treatment device, employing a process of first passing the wastewater through an electrochemical oxidation electrolyzer, followed by a capacitor deionization desalination unit. However, these technologies generally follow a traditional approach of degradation followed by desalination, utilizing the EO unit to mineralize organic matter as much as possible, with the goal of maximizing the direct removal of chemical oxygen demand (COD). While this method combines components structurally, it does not functionally address the core issue of excessive energy consumption inherent in the EO process and fails to reveal and utilize the deep-seated synergistic potential between the two technologies. In other solutions in this field, such as Chinese invention patent with publication number CN109607694A, a device and method for recycling concentrated water in a kasugamycin technical workshop is provided. It adopts a process sequence of CDI followed by EO. After CDI treatment, the conductivity of the water entering the EO unit is reduced. The low conductivity reduces the current efficiency of the EO unit and increases energy consumption. This design also fails to solve the technical problem of increased ineffective energy consumption and decreased overall energy efficiency.

[0006] Furthermore, existing EO processes typically rely on high current densities and long electrolysis times to achieve deep mineralization of organic pollutants, with specific energy consumption often exceeding 30 kWh / m³. 3 High operating costs and energy consumption limit its large-scale application in engineering. While CDI technology can remove inorganic salt ions from solutions at relatively low voltages, it has almost no ability to remove electrically neutral and recalcitrant organic compounds such as phenol. In existing technologies, EO and CDI are mostly operated as independent unit processes, making it difficult to achieve synergistic control of COD and salinity in a single process. This makes it difficult to meet the engineering requirements for synergistic purification and energy saving of complex wastewater with high salinity and high COD.

[0007] In summary, there is an urgent need in this field for a novel technical solution that transcends the simple physical superposition of EO and CDI units in existing processes, fundamentally reshaping their functional positioning to achieve an integrated system with a synergistic effect of "1+1>2". The design aims to "ionize" organic matter with low energy consumption, thereby creating ideal adsorption conditions for the subsequent CDI unit, and ultimately providing a new method to significantly reduce the overall system energy consumption and greatly improve the processing efficiency. Summary of the Invention

[0008] In view of the above-mentioned deficiencies of the prior art, the purpose of the present invention is to provide a water treatment system and method coupled with electrochemical oxidation and capacitive deionization, which solves the technical problem that it is difficult to achieve simultaneous, efficient and low-energy removal of refractory organic pollutants and inorganic salts in high-salt and high-COD wastewater in the same treatment system.

[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows: In a first aspect of the present invention, a water treatment method coupled with electrochemical oxidation and capacitive deionization is provided, comprising the following steps: (1) Organic wastewater is introduced into an electrochemical oxidation unit, wherein the pollutants in the organic wastewater include non-ionized organic pollutants and inorganic salts; The electrochemical oxidation unit is operated under conditions where the current density and residence time are suitable for partially oxidizing at least a portion of the non-ionizing organic pollutants into ionizable organic intermediates. (2) The effluent generated by the operation of the electrochemical oxidation unit is introduced into the capacitor deionization unit; the effluent contains the ionizable organic intermediate and the inorganic salt; (3) The capacitor deionization unit is operated to synergistically adsorb the ionizable organic intermediates and the inorganic salts to produce treated water with reduced chemical oxygen demand and salinity.

[0010] Preferably, in step (1), the non-ionizable organic pollutant includes aromatic compounds; the ionizable organic intermediate includes one or more carboxylic acids.

[0011] More preferably, the non-ionizing organic pollutant includes phenol; and the ionizable organic intermediate includes at least one of acetic acid, oxalic acid, and maleic acid.

[0012] Preferably, in step (1), the cation of the inorganic salt includes Na. + Ca 2+ One or two of them, including anions such as Cl. - or Cl - and SO4 2- .

[0013] Preferably, in step (1), the electrochemical oxidation unit operates at 3~15 mA·cm⁻¹. -2 It operates at a current density and has a dwell time of 10~60 min.

[0014] Preferably, in step (3), the capacitor deionization unit is in the range of 0.5~5 mA·cm⁻¹. -2 It operates at a current density of 10~60 min.

[0015] Preferably, in the water treatment method coupled with electrochemical oxidation and capacitive deionization, when the chemical oxygen demand (COD) removal rate is ≥90%, the specific energy consumption of the method is ≤10 kWh·m³. -3 .

[0016] In a second aspect of the invention, a water treatment system coupled with electrochemical oxidation and capacitive deionization for use in the method of the first aspect of the invention is provided, comprising: An electrochemical oxidation unit includes a metal end plate, a gasket, an anode, a reaction chamber gasket, a cathode, a gasket, and a metal end plate stacked sequentially; the electrochemical oxidation unit is used to oxidize non-ionized organic pollutants to form ionizable organic intermediates; The capacitive deionization unit includes a metal end plate, a gasket, a current collector, an active electrode, a reaction chamber gasket, a dialysis membrane, a current collector, a gasket, and a metal end plate stacked sequentially. The capacitive deionization unit is connected downstream of the electrochemical oxidation unit to receive the effluent from the organic wastewater. The capacitive deionization unit is used to synergistically adsorb ionizable organic intermediates and inorganic salts from the effluent.

[0017] Preferably, in the electrochemical oxidation unit, the anode is a dimensionally stable anode (DSA), and the cathode is a titanium sheet.

[0018] Preferably, in the capacitor deionization unit, the active electrode is a capacitor electrode, which comprises activated carbon, a conductive agent, and a binder, in a mass ratio of 80~90:5~15:3~10.

[0019] Based on the above technical solutions, the design concept and principle of this invention are as follows: In existing technologies, EO and CDI are mostly operated as independent unit processes, making it difficult to achieve synergistic control of COD and salinity in a single process. This makes it difficult to meet the engineering requirements of synergistic purification and energy saving for complex wastewater with high salinity and high COD. To overcome these shortcomings, this invention proposes an electrochemical oxidation-capacitive deionization (EO-CDI) coupled water treatment system and its operation method based on the "ionization-adsorption" mechanism. The design concept of this system is to redefine the electrochemical oxidation unit from the traditional "complete mineralization unit" to an "organic matter ionization pretreatment unit," mainly to realize the conversion of recalcitrant organic matter into easily ionized intermediate products. Then, the capacitive deionization unit is used to synergistically electro-adsorb ionized intermediate products and inorganic salt ions, realizing the simultaneous removal of organic pollutants and inorganic salts in the same device, thereby reducing the overall specific energy consumption while maintaining high purification efficiency.

[0020] Under practical application conditions, the organic wastewater to be treated can be introduced into the EO unit from the storage tank by a peristaltic pump or similar means, and electrolytic oxidation is carried out in a constant current manner between a size-stable anode (such as Ti / RuO2-IrO2) and an inert cathode. Hydroxyl radicals (·OH) are first electrocatalyzed on the anode surface, and further react with Cl in the chlorine-containing wastewater. - The reaction produces HClO / ClO in situ.- These highly reactive chlorine species are subjected to a series of attacks on aromatic recalcitrant organic compounds such as phenol, causing them to undergo hydroxylation, ring-opening, and other steps, gradually transforming them into low-molecular-weight organic acid intermediates such as acetic acid, oxalic acid, and maleic acid. These intermediates exist in aqueous solution as anionic organic acids, thus transforming them from nonionic or weakly polar macromolecular organic compounds into charged species that are easily migrated by an electric field.

[0021] Wastewater from the EO unit is introduced into the CDI unit, where a DC electric field is applied between a pair of porous conductive electrodes primarily composed of activated carbon. The electrical double layer formed in the CDI unit provides numerous charge storage sites for the cathode and anode electrodes, reducing the amount of Na+ in the wastewater. + Ca 2+ Cl - SO4 2- Inorganic salt ions and organic acid anions generated during the EO stage (such as CH3COO) - C2O4 2- C4H2O4 2- Driven by an electric field, the electrodes migrate and accumulate on the porous electrode surface with opposite polarities, and are fixed in the electric bilayer structure to achieve electroadsorption removal; then, electrode regeneration and pollutant desorption are completed by reverse pressure or short-circuiting the electrodes to achieve continuous operation.

[0022] By adjusting the matching relationship between the EO unit current density and treatment time, and the CDI unit operating current and water flow time, the system can achieve an optimal overall balance between COD removal rate, desalination rate, and specific energy consumption. As presented in one or more embodiments of the present invention, when treating simulated high-salinity wastewater containing phenol, an operating strategy such as "20 min EO + 40 min CDI" can achieve a COD removal rate of over 80% and a significant decrease in conductivity, with a specific energy consumption of only about 12 kWh·m³. -3 The energy consumption is significantly lower than that required for standalone EO operation under the same conditions. When treating actual high-salt, high-COD wastewater from cooling towers of thermal power plants, this invention employs a "30 min EO (5 mA·cm⁻¹)" method. -2 + 30 min CDI (1 mA·cm) -2 The coupling mode of ")" ensures a COD removal rate of over 95% while consuming only 7.6 kWh·m³. -3 Compared to a single EO process with the same current density and treatment time, it saves more than 55% energy; after 50 consecutive operating cycles, the COD and salinity removal rates remain above 95% of their initial values, and the system exhibits excellent electrochemical stability and anti-fouling performance.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) In the EO-CDI integrated process, the present invention clearly constructs the “ionization-adsorption” synergistic mechanism, reconstructs the electrochemical oxidation unit from the traditional high-energy-consuming complete mineralization unit to the organic matter ionization pretreatment unit, so that the recalcitrant organic matter enters the CDI unit in the form of ionization intermediates and completes electro-adsorption removal together with inorganic salt ions, thereby achieving synergistic control of COD and salinity from the mechanism level.

[0024] (2) The overall energy consumption required by the present invention is significantly reduced. By rationally allocating the functions of EO and CDI in the removal load, the EO unit is avoided from undertaking all organic mineralization tasks. While achieving a COD removal rate comparable to or even higher than that of a long-term single EO process, the total specific energy consumption of the system can be reduced by about 40% to 60%, effectively alleviating the problem of high energy consumption in traditional electrochemical oxidation processes and improving the economic efficiency of the process in engineering applications.

[0025] (3) The present invention is applicable to a wide range of organic wastewater types. It is not only suitable for simulated high-salt wastewater containing typical recalcitrant organic compounds such as phenol, but also shows good treatment effect on actual high-salt and high-COD complex wastewater such as the cooling tower wastewater of thermal power plants containing a variety of inorganic salts and organic pollutants. It has excellent universality and promotion value.

[0026] (4) The system structure of the present invention is simple and easy to modularize and scale up. Both the EO unit and the CDI unit adopt a plate-type modular structure, which can be flexibly combined in series or parallel according to the water treatment volume requirements. The electrode regeneration process can be completed by switching electrical signals without the need for additional chemical reagents. The system structure is simple and easy to control, which is conducive to realizing continuous and automated operation and engineering scale-up applications. Attached Figure Description

[0027] Figure 1 This is a structural breakdown diagram of the core reactor in a water treatment system that couples chemical oxidation and capacitive deionization; where (a) is the assembly structure of the electrochemical oxidation unit and (b) is the assembly structure of the capacitive deionization unit. Figure 2 The graph shows the performance comparison between the electrochemical oxidation and capacitive deionization coupled water treatment method and the single process for treating phenol simulated wastewater; where (a) shows the change of solution conductivity over time under different process conditions, and (b) shows the change of COD concentration over time under different process conditions. Figure 3The figure shows the comprehensive performance evaluation of the water treatment method of electrochemical oxidation and capacitive deionization coupling for treating the cooling tower wastewater of a thermal power plant. Among them, (a) is the removal rate of various inorganic ions in the water by the system, (b) is the comparison of COD removal rate under different treatment strategies and different current densities, and (c) is the comparison of specific energy consumption (EC) corresponding to (b). Detailed Implementation

[0028] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0029] In the following embodiments: Simulated wastewater preparation: Dissolve analytical grade phenol (100 mg / L) in deionized water. -1 ) and anhydrous sodium sulfate (6.5 g L) -1 It is formulated to produce an initial COD of approximately 200 mg / L of wastewater. -1 The initial conductivity is approximately 8 mS / cm. -1 .

[0030] Pretreatment of real industrial wastewater: The industrial wastewater comes from the circulating water of a cooling tower in a thermal power plant, with an initial COD of 800~1000 mg / L. -1 The initial conductivity is approximately 40 mS / cm. -1 Before being fed into the device for processing, it is first passed through a 0.22 μm filter membrane to remove suspended solids and then diluted 5 times with deionized water.

[0031] Example 1 This embodiment provides a water treatment method that couples electrochemical oxidation with capacitive deionization. Based on the synergistic effect of the two methods, the steps are as follows: (1) The simulated wastewater was introduced into the electrochemical oxidation unit, and the electrochemical oxidation unit was run; the volume of the simulated wastewater was 30 mL, and the current density used in the electrochemical oxidation unit was 10 mA·cm. -2 The stay time is 20 minutes; (2) The effluent generated by the operation of the electrochemical oxidation unit is introduced into the capacitor deionization unit; (3) The capacitor deionization unit is operated in constant current mode with a working current of 2 mA·cm. -2 The residence time is 40 min, and the produced water has reduced chemical oxygen demand and salinity.

[0032] This embodiment is denoted as 20 EO+40 CDI, which means that the electrochemical oxidation unit is used for 20 minutes first, and then the effluent is passed to the capacitor deionization unit for 40 minutes.

[0033] As shown in Figure 1, the water treatment system using the electrochemical oxidation and capacitive deionization coupling method in this embodiment includes an electrochemical oxidation unit and a capacitive deionization unit. The electrochemical oxidation module, from left to right, consists of a metal end plate, a silicone gasket, a DSA electrode, a reaction chamber gasket, a titanium sheet, a silicone gasket, and a metal end plate. The capacitive deionization module, from left to right, consists of a metal end plate, a silicone gasket, a current collector (high-purity titanium sheet), an active electrode, a reaction chamber gasket, a dialysis membrane, a current collector, a silicone gasket, and a metal end plate. The DSA electrode is a finished ruthenium-iridium titanium electrode (the titanium plate has a ruthenium dioxide and iridium dioxide coating), which has good electrocatalytic activity. The active electrode is a finished activated carbon electrode, made by coating a slurry composed of activated carbon particles, conductive particles, and a binder onto conductive carbon cloth, and has good ion adsorption performance.

[0034] Example 2 This embodiment uses a water treatment system that couples electrochemical oxidation and capacitive deionization as described in Example 1 to treat simulated wastewater. The method in this embodiment is basically the same as that in Example 1, except that in this embodiment, the electrochemical oxidation unit is run for 30 minutes first, and then the effluent is passed to the capacitive deionization unit for 30 minutes.

[0035] This embodiment is denoted as 30 EO+30 CDI, which means that the electrochemical oxidation unit is first run for 30 minutes, and then the effluent is passed to the capacitor deionization unit for 30 minutes.

[0036] Example 3 This embodiment uses a water treatment system that couples electrochemical oxidation and capacitive deionization as described in Example 1 to treat simulated wastewater. The method in this embodiment is basically the same as that in Example 1, except that in this embodiment, the electrochemical oxidation unit is run for 40 minutes first, and then the effluent is passed to the capacitive deionization unit for 20 minutes.

[0037] This embodiment is denoted as 40 EO+20 CDI, which means that the electrochemical oxidation unit is used for 40 minutes first, and then the effluent is passed to the capacitor deionization unit for 20 minutes.

[0038] Example 4 This embodiment uses the electrochemical oxidation and capacitive deionization coupled water treatment system as described in Example 1 to treat 30 mL of pretreated real wastewater. The electrochemical oxidation unit operates at two different current densities (5 mA·cm⁻¹). -2 10 mA·cm -2The capacitor deionization unit operates at a current density of 1 mA·cm⁻¹. -2 Run it.

[0039] In this embodiment (30 EO+30 CDI), the electrochemical oxidation unit was first run for 30 minutes, and then the effluent was passed to the capacitor deionization unit for 30 minutes, for a total duration of 60 minutes.

[0040] Comparative Example 1 This comparative example uses only the capacitor deionization unit as described in Example 1 to treat simulated wastewater, with a running time of 60 minutes. This comparative example is denoted as Only CDI.

[0041] Comparative Example 2 This comparative example uses only the electrochemical oxidation unit as described in Example 1 to treat simulated wastewater, with an operating time of 60 min. This comparative example is denoted as Only EO.

[0042] Comparative Example 3 This comparative example uses the electrochemical oxidation unit as described in Example 1 to treat pretreated real wastewater, with the electrochemical oxidation unit running alone for 30 min. This comparative example is denoted as 30 EO.

[0043] Comparative Example 4 This comparative example uses the electrochemical oxidation unit as described in Example 1 to treat pretreated real wastewater, with the electrochemical oxidation unit running alone for 60 min. This comparative example is denoted as 60 EO.

[0044] Test Example 1 This test case aims to verify the synergistic effect of the electrochemical oxidation and capacitive deionization coupling method described in this application.

[0045] Five groups, including Examples 1-3 and Comparative Examples 1 and 2, were used for comparison. The experimental results are shown in [Figure Number]. Figure 2 .like Figure 2 As shown in (a), Comparative Example 1 (Only CDI) exhibits the best desalination rate, while the conductivity of Comparative Example 2 (Only EO) remains essentially unchanged. The coupling processes in this application all achieve significant desalination effects. (Refer to...) Figure 2 (b) The synergistic effect is particularly significant in COD removal. Comparative Example 1 (Only CDI) showed almost no COD removal capability, while Comparative Example 2 (Only EO) achieved only about 30% COD removal within 60 min. However, all coupled processes in this application showed COD removal rates far superior to single processes, with the "30 EO+30 CDI" and "40 EO+20 CDI" processes achieving COD removal rates exceeding 80% after 60 min of treatment.

[0046] Test Example 2 This test case aims to evaluate the actual performance and energy efficiency advantages of the method of the present invention in treating real industrial wastewater.

[0047] Using Example 4 and Comparative Examples 3 and 4 as comparisons, the experimental results are as follows: Figure 3 As shown. (Refer to...) Figure 3 (a) The coupling system of the present invention is effective against various inorganic ions present in real wastewater (such as Na+). + Al 3+ Cl - SO4 2- (etc.) showed good removal effects, making up for the deficiency of EO processes in removing inorganic ions, and confirming the universality and strong comprehensive purification capability of the method described in this invention in complex water bodies. (Refer to...) Figure 3 (b) Regarding COD removal, the "30 EO+30 CDI" group in this embodiment of the invention achieved a COD removal rate exceeding 95% at both current densities, comparable to Comparative Example 4 (60 min EO treatment) with the same treatment time, and significantly superior to Comparative Example 3 (30 min EO treatment). (Refer to...) Figure 3 (c) In terms of specific energy consumption, the "30 EO+30 CDI" process in this application achieves a specific energy consumption of 5 mA·cm⁻¹. -2 The specific energy consumption at current density is only 7.6 kWh·m. -3 In stark contrast, under the same process, the current density is 10 mA·cm⁻¹. -2 At that time, the specific energy consumption reached 17 kWh·m -3 Comparative Example 4 (60 min EO treatment), which achieved a similar treatment effect, was at 5 mA·cm⁻¹. -2 Specific energy consumption reaches 12.5 kWh·m -3 At 10 mA·cm -2 The energy consumption is as high as 31 kWh·m -3 The results show that the method described in this application can achieve the same COD removal effect as single EO treatment under different current densities, while saving more than 55% of power consumption, demonstrating extremely significant energy-saving effect.

[0048] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A water treatment method coupled with electrochemical oxidation and capacitive deionization, characterized in that, Includes the following steps: (1) Organic wastewater is introduced into an electrochemical oxidation unit, wherein the pollutants in the organic wastewater include non-ionized organic pollutants and inorganic salts; The electrochemical oxidation unit is operated under conditions where the current density and residence time are suitable for partially oxidizing at least a portion of the non-ionizing organic pollutants into ionizable organic intermediates. (2) The effluent generated by the operation of the electrochemical oxidation unit is introduced into the capacitor deionization unit; the effluent contains the ionizable organic intermediate and the inorganic salt; (3) The capacitor deionization unit is operated to synergistically adsorb the ionizable organic intermediates and the inorganic salts to produce treated water with reduced chemical oxygen demand and salinity.

2. The water treatment method according to claim 1, characterized in that: In step (1), the non-ionizable organic pollutant includes aromatic compounds; the ionizable organic intermediate includes one or more carboxylic acids.

3. The water treatment method according to claim 2, characterized in that: The non-ionizing organic pollutant includes phenol; the ionizable organic intermediate includes at least one of acetic acid, oxalic acid, and maleic acid.

4. The water treatment method according to claim 1, characterized in that: In step (1), the cation of the inorganic salt includes Na. + Ca 2+ One or two of them, including anions such as Cl. - or Cl - and SO4 2- .

5. The water treatment method according to claim 1, characterized in that: In step (1), the electrochemical oxidation unit operates at 3~15 mA·cm⁻¹. -2 It operates at a current density and has a dwell time of 10~60min.

6. The water treatment method according to claim 1, characterized in that: In step (3), the capacitor deionization unit is in the range of 0.5~5 mA·cm⁻¹ -2 It operates at a current density of 10~60 min.

7. The water treatment method according to claim 1, characterized in that: The water treatment method coupled with electrochemical oxidation and capacitive deionization has a specific energy consumption of ≤10 kWh·m³ when the chemical oxygen demand (COD) removal rate is ≥90%. -3 .

8. A water treatment system using the method described in any one of claims 1 to 7, characterized in that, include: An electrochemical oxidation unit includes a metal end plate, a gasket, an anode, a reaction chamber gasket, a cathode, a gasket, and a metal end plate stacked sequentially; the electrochemical oxidation unit is used to oxidize non-ionized organic pollutants to form ionizable organic intermediates; The capacitive deionization unit includes a metal end plate, a gasket, a current collector, an active electrode, a reaction chamber gasket, a dialysis membrane, a current collector, a gasket, and a metal end plate stacked sequentially. The capacitive deionization unit is connected downstream of the electrochemical oxidation unit to receive the effluent from the organic wastewater. The capacitive deionization unit is used to synergistically adsorb ionizable organic intermediates and inorganic salts from the effluent.

9. The water treatment system coupled with electrochemical oxidation and capacitive deionization according to claim 8, characterized in that: In the electrochemical oxidation unit, the anode is a size-stable anode, and the cathode is a titanium sheet.

10. The water treatment system coupled with electrochemical oxidation and capacitive deionization according to claim 8, characterized in that: The capacitor deionization unit has a capacitor electrode as its active electrode, which comprises activated carbon, a conductive agent, and a binder in a mass ratio of 80~90:5~15:3~10.

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