Electrochemically driven ion exchange system

Abstract

This invention belongs to the field of water treatment technology, and particularly relates to an electrochemically driven ion exchange system. The device includes: a multi-channel electrochemical workstation, wires, an electrolytic cell, silica gel tubing, a peristaltic pump, a glass chromatography column, filter media, and a filter membrane. The anode and cathode of the electrolytic cell are separated by a cation exchange membrane. The multi-channel electrochemical workstation supplies power to the electrolytic cell via wires, causing the anode to generate acid and the cathode to generate alkali. The peristaltic pump pumps the acid or alkali solution into the glass chromatography column filled with filter media through the silica gel tubing. The method includes: an acidification stage, in which the anode acid solution is passed into the glass chromatography column to increase the adsorption capacity of the filter media; an adsorption stage, in which raw water is passed into the glass chromatography column to adsorb pollutants; a regeneration stage, in which the cathode alkali solution is passed into the glass chromatography column to restore the adsorption capacity of the saturated filter media; and a recovery stage, in which the regenerated waste liquid is passed into the cathode region of the electrolytic cell to reduce precipitation. This invention reduces operating costs and the risk of secondary pollution through efficient activation, green regeneration, and harmless recovery.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and particularly relates to an electrochemically driven ion exchange apparatus and method. Background Technology

[0002] In the field of water treatment technology, ion exchange technology is widely used for the deep removal of pollutants such as heavy metals due to its high selectivity, high removal efficiency, and large adsorption capacity for specific pollutant ions. Traditional ion exchange processes rely on the external addition of chemical agents to activate (e.g., acidification) and regenerate (e.g., alkaline washing) the exchange resin. However, this approach has significant limitations: on the one hand, achieving high adsorption capacity often requires large amounts of acid for pretreatment, while resin regeneration requires large amounts of alkali, resulting in high agent costs; on the other hand, the chemical regeneration process generates concentrated wastewater with high salt content and high concentrations of pollutants, requiring additional harmless treatment, increasing process complexity and environmental risks. Furthermore, the transportation, storage, and safe disposal of chemical agents also limit the application of this technology in decentralized, small-scale wastewater treatment scenarios.

[0003] To overcome the aforementioned shortcomings, electrochemical technology has attracted attention as a green technology. It can generate acidic or alkaline solutions in situ through the electrolysis of water or salt solutions, and the process is clean and controllable. Existing technologies attempt to apply electrochemistry to water treatment, but they mostly focus on direct treatment processes such as electrocoagulation and electrooxidation, or only utilize electrochemistry for the preparation of regenerants. There are limitations in the close coupling and functional synergy between electrochemistry and ion exchange adsorption processes. In particular, for weakly basic anion exchange resins, although their theoretical adsorption capacity is high, in practical applications, the adsorption capacity cannot be fully utilized due to surface impurities or insufficient protonation. At the same time, in the traditional alkaline regeneration process, the diffusion resistance of hydroxide ions inside the resin particles is large, resulting in low regeneration efficiency and high alkali consumption. In addition, existing electrochemical and ion exchange coupling processes can only be used for the synergistic regeneration of saturated resins, failing to improve the adsorption capacity of the resin itself. Therefore, how to combine the advantages of in-situ acid and alkali production by electrochemistry with the high-efficiency adsorption characteristics of ion exchange to build an integrated system that can simultaneously improve the resin adsorption capacity and regeneration efficiency in a green and low-cost manner has become a technical problem that urgently needs to be solved in this field.

[0004] Therefore, there is an urgent need for an electrochemically driven ion exchange device and method to solve this problem. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for electrochemically driven ion exchange to solve the above-mentioned problems.

[0006] To achieve the above objectives, the present invention provides the following solution: An electrochemically driven ion exchange device, comprising: A glass chromatography column, wherein the glass chromatography column is provided with a wastewater inlet, an acid inlet, an alkali inlet, a wastewater outlet, an acid outlet, and an alkali outlet; The acid inlet and the alkali inlet are connected to the electrolytic cell. The electrolytic cell includes a cell body and a cation exchange membrane located in the middle of the cell body. The cation exchange membrane divides the electrolytic cell into an acid region and an alkali region. An anode is provided in the acid region and a cathode is provided in the alkali region. Both the anode and the cathode are electrically connected to a multi-channel electrochemical workstation. The acid inlet is connected to the outlet of the acid region, and the alkali inlet is connected to the outlet of the alkali region. The electrolytic cell is used to hold an electrolyte and electrolyze it to produce an acid solution at the anode and an alkaline solution at the cathode. The glass chromatography column is filled with filter media; The acid outlet and the alkali outlet are respectively connected to the acid treatment equipment and the alkali treatment equipment.

[0007] Optionally, two filter membranes are fixed inside the glass chromatography column, and a space for storing the filter media is formed between the inner wall of the glass chromatography column and the two filter membranes.

[0008] Optionally, the acid inlet and the outlet of the acid region, and the alkali inlet and the outlet of the alkali region are all connected by a silicone tube, and a peristaltic pump is provided in the middle of the silicone tube to drive the liquid flow.

[0009] Optionally, both the anode and the cathode are electrically connected to the multichannel electrochemical workstation via wires.

[0010] Optionally, the filter media is a weak alkali resin.

[0011] Optionally, the pH of the acid solution is 2.

[0012] Optionally, the pH value of the alkaline solution is 12-13.

[0013] An electrochemically driven ion exchange method includes the following steps: The multi-channel electrochemical workstation is turned on so that the anode and the cathode electrolyze the electrolyte in the electrolytic cell to form acid and alkali solutions. To increase the adsorption capacity of the filter media, the acid solution in the electrolytic cell is passed into the glass chromatography column; When treating wastewater or source water, the influent is passed through the glass chromatography column and purified by ion exchange with the filter media. To restore the adsorption capacity of the filter media, the alkaline solution in the electrolytic cell is passed into the glass chromatography column.

[0014] Compared with the prior art, the present invention has the following advantages and technical effects: This invention integrates an electrolytic cell with an ion exchange column, utilizing an electrochemical method to generate a regenerant in situ in a green manner, achieving a synergistic improvement in adsorption efficiency, regeneration economy, and harmless recycling. Specifically, the effects are as follows: First, the acid solution generated in situ at the anode of the electrolytic cell pre-treatment of the weakly basic anion exchange resin effectively increases the resin's protonation degree and exchange site activity, thereby raising its equilibrium adsorption capacity for heavy metal ions to near the level of strong-base resins, solving the problem of the low actual adsorption capacity of weakly basic resins. Second, regeneration using an alkaline solution generated in situ at the cathode of the electrolytic cell avoids the addition, transportation, and storage of external chemical regenerants, reducing operating costs; the sulfate ions in the regenerant promote resin swelling and improve the mass transfer efficiency of hydroxide ions within the resin phase, thus achieving efficient regeneration at a relatively low alkaline concentration, and maintaining a high regeneration recovery efficiency. Finally, some of the concentrated regenerant containing heavy metal ions can be reduced in hazard through an electrochemical reduction reaction, and after precipitation and recovery, it achieves harmless treatment. This integrated device combines electrolysis, acidification, adsorption, regeneration, and recycling processes, achieving "electricity instead of chemicals." This not only reduces the consumption of chemical reagents and the risk of secondary pollution but also simplifies the operation process, making it more suitable for cost-sensitive and decentralized wastewater or drinking water treatment scenarios. Overall, it achieves a balance between treatment effect, operating cost, and environmental friendliness. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described 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 these drawings without creative effort. Figure 1 This is a schematic diagram of the apparatus and method of the present invention; Figure 2 This is a schematic diagram showing the pH changes of the anolyte acid and the cathode alkaline solution over time during the electrolysis process of this invention. Figure 3 This is a schematic diagram showing the effect of the acidification and regeneration processes on resin properties according to the present invention. Figure 4 This is a schematic diagram illustrating the changes in resin properties during the treatment of chromium-containing wastewater according to the present invention. Figure 5 This is a schematic diagram illustrating the changes in resin performance during the treatment of chromium-contaminated water sources according to the present invention. Figure 6 This is a schematic diagram showing the change of Cr(VI) concentration in the cathode solution over time during the recovery process of this invention; Among them, 1. Multi-channel electrochemical workstation; 2. Wires; 3. Electrolytic cell; 4. Anode; 5. Cathode; 6. Cation exchange membrane; 7. Silica gel tube; 8. Peristaltic pump; 9. Glass chromatography column; 10. Filter media; 11. Filter membrane. Detailed Implementation

[0016] 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 some embodiments of the present invention, and not all embodiments. 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.

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Reference Figures 1 to 6 This invention discloses an electrochemically driven ion exchange device, comprising: Glass chromatography column 9, which is equipped with wastewater inlet, acid inlet, alkali inlet, wastewater outlet, acid outlet and alkali outlet; The acid inlet and the alkali inlet are connected to the electrolytic cell 3. The electrolytic cell 3 includes a cell body and a cation exchange membrane 6 located in the middle of the cell body. The cation exchange membrane 6 divides the electrolytic cell 3 into an acid region and an alkali region. An anode 4 is provided in the acid region and a cathode 5 is provided in the alkali region. Both the anode 4 and the cathode 5 are electrically connected to the multi-channel electrochemical workstation 1. The acid inlet is connected to the outlet of the acid region and the alkali inlet is connected to the outlet of the alkali region. Electrolytic cell 3 is used to hold electrolyte and electrolyze it to produce acid solution at anode 4 and alkaline solution at cathode 5. The glass chromatography column 9 is filled with filter media 10; The acid outlet and alkali outlet are connected to the acid treatment equipment and alkali treatment equipment, respectively.

[0019] First, electrolytes, such as sodium sulfate solution, are placed in the acid and alkali zones of electrolytic cell 3. Electrolysis is then performed by supplying power to the anode 4 and cathode 5 through the multi-channel electrochemical workstation 1, resulting in the generation of acid on the anode 4 side and alkali on the cathode 5 side. When it is necessary to increase the adsorption capacity of the filter media 10 in the glass chromatography column 9, the acid solution in the acid zone is pumped into the glass chromatography column 9 through the acid inlet to acidify the filter media 10. During water treatment, raw water is pumped into the glass chromatography column 9 through the wastewater inlet, flows through the filter media 10 to undergo ion exchange, and the purified water is discharged from the wastewater outlet. When the filter media 10 becomes saturated and its adsorption capacity needs to be restored, the alkali solution in the alkali zone is pumped into the glass chromatography column 9 through the alkali inlet to regenerate the filter media 10. The used waste acid and waste alkali are discharged to the corresponding treatment equipment through the acid outlet and alkali outlet, respectively. This device highly integrates the electrolytic acid and alkali production unit with the ion exchange unit, realizing the in-situ, green production and supply of acid and alkali solutions. It replaces the external addition of chemical reagents, reduces operating costs, and avoids the risk of secondary pollution.

[0020] As an optional implementation, two filter membranes 11 are fixed inside the glass chromatography column 9, and a space for storing filter media 10 is formed between the inner wall of the glass chromatography column 9 and the two filter membranes 11.

[0021] Two filter membranes 11 are fixedly installed inside the glass chromatography column 9. These two filter membranes 11, together with the inner wall of the chromatography column, form a relatively closed containment space, in which the filter media 10 is filled and confined. The upper and lower filter membranes 11 can effectively support and fix the filter media 10 particles, preventing them from being lost or clogging the pipeline under the action of liquids such as acid, alkali, and wastewater, ensuring the stable operation of the filtration and regeneration process, while also facilitating the filling and replacement of the filter media 10.

[0022] As an optional implementation, the acid inlet and the outlet of the acid zone, as well as the alkali inlet and the outlet of the alkali zone, are connected by a silicone tube 7. A peristaltic pump 8 is provided in the middle of the silicone tube 7, which is used to drive the liquid flow.

[0023] The acid outlet of the electrolytic cell 3 is connected to the acid inlet of the glass chromatography column 9 via silicone tubing 7, and similarly, the alkali outlet is connected to the alkali inlet via silicone tubing 7. A peristaltic pump 8 is installed in the middle of each connecting line. During operation, the flow rate of acid or alkali from the electrolytic cell 3 to the glass chromatography column 9 is precisely driven and metered by controlling the start, stop, and speed of the peristaltic pump 8. The peristaltic pump 8 provides stable and reliable liquid transport power, and the silicone tubing 7 has good chemical inertness and flexibility, making it suitable for transporting acid and alkali liquids. The entire transport system has a simple structure and is easy to control.

[0024] As an optional implementation, both the anode 4 and the cathode 5 are electrically connected to the multichannel electrochemical workstation 1 via the wire 2.

[0025] Anode 4 and cathode 5 are connected to their respective electrode interfaces of the multi-channel electrochemical workstation 1 via independent wires 2. This establishes a stable and reliable power transmission path, ensuring that the voltage and current output from the multi-channel electrochemical workstation 1 can be precisely and independently applied to anode 4 and cathode 5, thereby achieving precise control of the electrolysis reaction and ensuring the stable production of acid and alkali solutions as needed.

[0026] As an optional implementation, the filter media 10 is a weakly basic resin.

[0027] A weak base resin, such as a weak base anion exchange resin, is used as filter media 10 and packed into a glass chromatography column 9. In the acidification stage, the acid generated by electrolysis can effectively protonate the functional groups of the weak base resin; in the adsorption stage, the protonated weak base anion exchange resin can efficiently adsorb anionic pollutants such as Cr(VI) in wastewater; in the regeneration stage, the alkaline solution can desorb and regenerate it.

[0028] As an optional implementation, the pH of the acid solution is 2.

[0029] By controlling the electrolysis parameters of the multi-channel electrochemical workstation 1, such as voltage, current density, and electrolysis time, the pH value of the acid solution generated on the anode 4 side of the electrolytic cell 3 is controlled at around 2. Under this pH condition, the acid solution can most effectively acidify the weak-base resin filter media 10, fully protonating its functional groups and maximizing its subsequent adsorption capacity for pollutant ions. This is one of the key process conditions for optimizing the overall system's treatment efficiency.

[0030] As an optional implementation method, the pH value of the alkaline solution is 12-13.

[0031] By controlling the electrolysis parameters of the multi-channel electrochemical workstation 1, the pH value of the alkaline solution generated on the cathode 5 side of the electrolytic cell 3 is controlled within the range of 12 to 13. Within this pH range, the alkaline solution has a sufficient concentration of hydroxide ions, which can efficiently displace pollutant ions such as chromate adsorbed on the filter media 10, thus regenerating the filter media 10. Simultaneously, the pH value is not too high, which helps control alkaline solution consumption and the difficulty of subsequent treatment. This is another key process condition for achieving green and efficient regeneration.

[0032] Specifically, the present invention provides an electrochemically driven ion exchange device, comprising a multi-channel electrochemical workstation 1, a wire 2, an electrolytic cell 3, an anode 4, a cathode 5, a cation exchange membrane 6, a silica gel tube 7, a peristaltic pump 8, a glass chromatography column 9, a filter media 10, and a filter membrane 11.

[0033] The multi-channel electrochemical workstation 1 is connected to the anode 4 and cathode 5 of the electrolytic cell 3 via wire 2. The electrolytic cell 3 is connected to the glass chromatography column 9 via silicone tube 7 and peristaltic pump 8.

[0034] The electrolytic cell 3 consists of an anode 4, a cathode 5, and a cation exchange membrane 6. The multi-channel electrochemical workstation 1 supplies power to the anode 4 and the cathode 5 through the wire 2.

[0035] The glass chromatography column 9 contains filter media 10, which undergoes a displacement reaction with pollutant ions in the wastewater. The filter membrane 11 is placed at the bottom to support the filter media 10 and prevent leakage and loss of the filter media 10.

[0036] Filter media 10 is represented by a weakly basic anion exchange resin, which can improve adsorption capacity through acidification and restore adsorption performance through regeneration.

[0037] Electrolytic cell 3 is connected to glass chromatography column 9 via silicone tube 7 and peristaltic pump 8. Acid solution is generated at anode 4 of electrolytic cell 3, and alkaline solution is generated at cathode 5 of electrolytic cell 3.

[0038] The sulfuric acid solution containing sodium sulfate produced by anode 4 is used for acidification of the filter media, and the sodium hydroxide alkaline solution containing sodium sulfate produced by cathode 5 is used for regeneration of the filter media.

[0039] An electrochemically driven ion exchange method, using the aforementioned electrochemically driven ion exchange apparatus, includes the following steps: The multi-channel electrochemical workstation 1 is turned on so that the anode 4 and cathode 5 electrolyze the electrolyte in the electrolytic cell 3 to form acid and alkali solutions. To increase the adsorption capacity of filter media 10, the acid solution in electrolytic cell 3 is passed into glass chromatography column 9; When treating wastewater or source water, the influent is purified by passing through the glass chromatography column 9 and undergoing ion exchange with the filter media 10. To restore the adsorption capacity of filter media 10, the alkaline solution in electrolytic cell 3 is passed into glass chromatography column 9.

[0040] First, the multi-channel electrochemical workstation 1 is powered on to the electrolytic cell 3. The anode 4 and cathode 5 within the electrolytic cell electrolyze the electrolyte, forming acid in the acidic region and alkali in the alkaline region, respectively. During the acidification stage, when it is necessary to increase the adsorption capacity of the filter media 10, the acid generated in the electrolytic cell 3 is passed into a glass chromatography column 9 filled with the filter media 10. During the adsorption stage, when water treatment is required, the wastewater or source water to be treated is passed through the glass chromatography column 9. The target ions in the water undergo ion exchange with the acidified filter media 10 and are adsorbed, achieving purification. During the regeneration stage, when the filter media 10 is saturated and its adsorption capacity needs to be restored, the alkaline solution generated in the electrolytic cell 3 is passed into the glass chromatography column 9 to regenerate the filter media 10. The used waste acid and waste alkali are discharged to the corresponding treatment equipment through the acid outlet and alkali outlet, respectively, for example, for electrochemical reduction and precipitation recovery of the waste alkali. The technical advantage of this method lies in integrating five steps—"electrolysis to produce reagents," "acid activation," "adsorption removal," "alkali regeneration," and "waste recovery"—into a closed-loop process. It utilizes in-situ electrochemically generated acid and alkali solutions to drive the activation and regeneration of ion exchange materials throughout the entire process, achieving "electricity-based drug replacement." Finally, in-situ electrochemical reduction enables harmless recycling. The entire process is highly automated, requires no external chemical reagents, significantly reduces operating costs, and avoids the secondary pollution and concentrated wastewater harmlessness issues that may arise from chemical regeneration. It represents a green and sustainable method for water treatment and material regeneration.

[0041] The working process of the electrochemical regeneration driven ion exchange device of the present invention is divided into five stages: electrolysis, acidification, adsorption, regeneration, and recovery.

[0042] During the electrolysis stage, the anode 4 of electrolytic cell 3 produces a sulfuric acid solution containing sodium sulfate (NaSO4), and the pH of the acid solution is controlled at around 2. The cathode 5 produces an alkaline solution, and the pH is controlled in the range of 12-13.

[0043] During the acidification stage, the acid solution generated by the anode 4 enters the glass chromatography column 9 through the silica gel tube 7 below the electrolytic cell 3 via the peristaltic pump 8, thereby directionally controlling the protonation state of the filter media 10 and improving the adsorption capacity.

[0044] During the adsorption stage, wastewater flows into the glass chromatography column 9 from the top and undergoes ion exchange with the filter media 10 to purify the wastewater, while the product water flows out from the bottom.

[0045] During the regeneration stage, the alkaline solution generated at cathode 5 enters the glass chromatography column 9 via the silica gel tube 7 below electrolytic cell 3 and peristaltic pump 8, utilizing SO42-. 2- The resin swelling effect enhances OH - Diffusion efficiency enables efficient regeneration under low-concentration alkaline solutions.

[0046] During the recovery stage, concentrated waste alkaline solution containing high concentrations of pollutants such as Cr(VI) enters the cathode 5 chamber of the electrolytic cell 3 through the silicone tube 7 and peristaltic pump 8. The anode 4 chamber contains NaSO4 solution. During the electrolysis process, the acidic environment of the cathode 5 chamber is continuously maintained to allow a reduction reaction to occur, causing Cr(VI) to be converted into Cr(III). Subsequently, the concentrated waste alkaline solution is recovered through a chemical precipitation reaction.

[0047] Application Example 1: The production of ion-exchange acidification and regeneration solutions was verified by constructing and adjusting a small-scale electrochemical reactor. The electrochemical reactor consisted of two plexiglass tanks, bolted together, and divided into two 500 mL chambers by a cation exchange membrane 6 (CEM, CMI-7000s). A ruthenium-iridium-titanium mesh was used as the anode 4, and a titanium mesh as the cathode 5, both with a surface area of ​​100 cm². 2 The process involves electrolyzing water to produce acidic solution in the anode tank and alkaline solution in the cathode tank, which are then used for acidification and regeneration. A 0.1 mol / L Na₂SO₄ solution is used as the electrolyte; sulfate is chosen because of its stability under cathode reduction (5) and anode oxidation (4) conditions. Before electrolysis begins, 500 mL of Na₂SO₄ electrolyte is added to each of the anode and cathode chambers. The electrochemical workstation voltage is set to 5V, and the current density is set to 2 mA / cm². 2 Electrolysis was performed in constant current mode, and the pH of the cation and anion tank solutions was measured every 4 minutes after the start of electrolysis. Figure 2 As shown, after the test stabilized, the actual voltage was 4.5V and the actual current was 0.25A. After 36 minutes, the pH of the alkaline solution in the cathode pool reached 12.18 and the pH of the acidic solution in the anode pool reached 2.00.

[0048] Application Example 2: This embodiment focuses on evaluating the impact of acidification and regeneration processes on the Cr(VI) removal performance and regeneration recovery effect of weak-base and strong-base anion exchange resins, such as... Figure 3 As shown. Figure 3 The results showed that after acidification with sulfuric acid (H2SO4), the equilibrium adsorption capacity of the weak base resin increased from 56.42 mg / g to 94.66 mg / g. Figure 3 b shows that the equilibrium adsorption capacity of the strong base resin is almost unaffected, indicating that acidification enhances the adsorption performance of the weak base resin to the level of the strong base resin, proving that the acidified weak base resin is an ideal alternative to the strong base resin.

[0049] To address the bottleneck in the regeneration efficiency of weak-base resins, this study deeply analyzed the influence of regenerator parameters (pH, additives) on resin regeneration. Different sodium hydroxide (NaOH) concentration gradients (pH=10-13) were established to investigate their effects on the regeneration efficiency of weak-base / strong-base resins. By comparing the effects of pure NaOH regenerated solution and mixed NaOH regenerated solution containing Na2SO4 on the regeneration effect of weak-base / strong-base resins, the recovery effect of the mixed regenerated solution was verified. Figure 3 c and Figure 3 The results show that, during regeneration with pure NaOH and Na₂SO₄-containing regenerators, the regeneration recovery efficiency of both strong and weak base resins reaches a relatively high level at pH values ​​of 12 and 13. Compared to pure NaOH regenerators, the mixed NaOH regenerator containing Na₂SO₄ has no significant effect on the regeneration recovery efficiency of weak base resins at pH values ​​of 12 and 13. Therefore, theoretically, electrochemically produced Na₂SO₄-containing regenerators with pH values ​​of 12-13 can optimize the recovery performance of the adsorption capacity of weak base resins.

[0050] Application Example 3 The apparatus of this invention was used to simulate the treatment of high-concentration Cr(VI) wastewater. The electrochemical workstation 1 operated under the same conditions as in Application Example 1. Resin was used as filter media 10 and filled into a glass chromatography column 9, with a filter membrane 11 placed at the bottom. The glass chromatography column 9 was wet-filled with approximately 17 mL of resin at a flow rate of 5 mL / min. The acid solution from the anode 4 generated in the reaction was introduced into the glass chromatography column 9 via a peristaltic pump 8 for resin acidification. After acidification, a 100 mg / L Cr(VI) solution was continuously introduced. Once the dynamic adsorption of the Cr(VI)-containing solution was verified to be saturated, the alkaline solution from the cathode 5 was introduced into the glass chromatography column 9 for resin regeneration. After regeneration, the above operation was repeated three times. Effluent samples were collected at fixed intervals to detect the pH and Cr(VI) concentration in the effluent, verifying the chromium removal and regeneration performance of the apparatus. To verify the long-term operation and regeneration stability of the weak base anion exchange resin reactor, a multi-cycle cyclic adsorption batch experiment was set up. Each cycle included acidification, adsorption, and regeneration processes. Both the acidification and regeneration solutions were produced from the electrochemical reactor. After each cycle, the changes in Cr(VI) concentration before and after adsorption were monitored, and the regeneration recovery rate for each cycle was finally obtained. The resin acidification, adsorption, and regeneration process and the multi-cycle regeneration recovery effect are shown in Table 1 and [Table data missing]. Figure 4 .

[0051] Depend on Figure 4 As can be seen from a, acidification saturation was reached at approximately 194 min (57 BV). The pH was maintained at 9-11 at the beginning of each cycle, indicating that the resin initially had a strong buffering capacity or had not yet completely released protons. Subsequently, the pH dropped rapidly, indicating that a large number of acidic groups were eluted, and acidification was completed. At the same time, the pH change trend of the three acidification cycles did not change significantly overall. Figure 4b indicates that the Cr(VI) effluent concentration was close to zero in the initial stage of each cycle, indicating that Cr(VI) was effectively adsorbed by the resin; subsequently, the concentration rose sharply, marking the appearance of the breakthrough point. As shown in Table 1, the treated water volume decreased from 15.3L to 14.6L after three cycles, and the adsorption capacity decreased successively, possibly due to the inactivation of active sites, structural damage, or interference from residual ions. Figure 4 c indicates that the regeneration efficiency remains high for the first 60 BV. As the regeneration time progresses, Cr(VI) in the resin is gradually released, and the regeneration effect does not significantly decrease with the increase of the number of cycles. Figure 4 d indicates that after ten cycles, the regeneration recovery efficiency of the resin is basically stable at over 90%. If the recovery rate decreases, a strong alkali can be used to increase the resin adsorption capacity. The sixth and seventh cycles demonstrate the resin's strong toughness.

[0052] Table 1. Dynamic regeneration recovery efficiency in three cycles. Application Example 4: The device of this invention was used to treat Cr(VI)-contaminated source water with a Cr(VI) concentration of 0.08 mg / L. The required effluent Cr(VI) concentration was below 0.05 mg / L (the limit of Class III of the "Surface Water Environmental Quality Standard" and the "Standards for Drinking Water Quality"), and the regenerated liquid discharge concentration was below 0.5 mg / L (the limit of the "Integrated Wastewater Discharge Standard"). The electrolysis reaction conditions and acidification-adsorption-regeneration steps were the same as in Application Examples 1 and 3. Effluent samples were collected at fixed intervals to detect the pH and Cr(VI) concentration in the effluent, verifying the device's treatment effect on real Cr(VI)-containing water samples. Furthermore, a 0.08 mg / L Cr(VI) solution was used to simulate real Cr(VI)-containing source water and passed through a 10 mL resin glass chromatography column 9 filled with pre-acidified resin. The change in Cr(VI) concentration in the effluent was monitored to verify the long-term chromium removal effect. The resin acidification, adsorption, and regeneration process and the long-term effluent concentration changes are described in [details omitted]. Figure 5 .

[0053] Figure 5 a indicates that acidification protonates the functional groups of the resin, enhancing its adsorption capacity for Cr(VI). When the pH stabilizes at 2, it means that the resin is fully activated and can enter the adsorption stage. Figure 5 b indicates that the resin has a good removal effect on Cr(VI) in the source water, with strong initial adsorption capacity, and can effectively control the Cr(VI) concentration within the safe range (0.05 mg / L) within 600 BV, indicating that the resin has a high dynamic adsorption capacity. Figure 5c indicates that the sharp decrease in Cr(VI) concentration within the 0-50 BV time range demonstrates the excellent regeneration capacity of the cathode alkaline solution. The final Cr(VI) concentration in the regenerated solution is below 0.5 mg / L, indicating that the resin not only restored most of its adsorption activity but also met the emission standards. Figure 5 The results show that even after 41320 BV, the resin still maintains a strong chromium removal capacity, reducing the concentration of Cr(VI) in the influent to below 0.05 mg / L, meeting the standard limit, and the treated water volume can reach 413.2 L. In summary, the electrochemical regeneration-driven ion exchange device and method based on weak base anion exchange resin has excellent potential for long-term chromium removal and green regeneration, and is suitable for low-cost treatment of chromium-contaminated source water.

[0054] Application Example 5: The concentrated Cr(VI) solution generated during regeneration was directly pumped into the cathode region of the electrolytic cell and reduced to Cr(III) in an acidic environment, ultimately converting to Cr(OH)3 precipitate in an alkaline environment. The recovery process simulated concentrated chromium solution by preparing 100 mg / L and 10 mg / L Cr(VI) solutions containing 0.1 mol / L Na₂SO₄ at pH=2 as catholytes, and preparing a 0.1 mol / L Na₂SO₄ solution as an anolyte. Electrochemical parameters similar to those in Application Example 1 were set, and the pH value and Cr(VI) concentration of the catholyte were monitored in real time during the electrolysis process. Three sets of recovery conditions were set in the 100 mg / L Cr(VI) catholyte: original catholyte, initial adjustment of the catholyte pH to 2 acidic environment, and continuous maintenance of the catholyte pH to 2 acidic environment. Figure 6 As shown in Figure a, maintaining a continuously acidic catholy solution pH of 2 can minimize Cr(VI) and achieve optimal recovery. Figure 6 As shown in b, the Cr(VI) concentration decreased during the recovery process in a stable acidic environment. Specifically, the initial Cr(VI) concentration in the catholyte from 10 mg / L decreased to 0.32 mg / L after 150 min (less than the wastewater discharge standard of 0.5 mg / L). After the reduction reaction was completed, the pH of the catholyte was adjusted to alkaline, and a white colloidal precipitate of Cr(OH)3 was observed at the bottom. The reaction is as follows: Cr2O7 2- +14H + +6e - →2Cr 3+ +7H2O Cr 3+ +3OH - →Cr(OH)3 In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0055] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A device for electrochemically driven ion exchange, characterized in that, include: A glass chromatography column (9) is provided with a wastewater inlet, an acid inlet, an alkali inlet, a wastewater outlet, an acid outlet, and an alkali outlet; The acid inlet and the alkali inlet are connected to the electrolytic cell (3). The electrolytic cell (3) includes a cell body and a cation exchange membrane (6) located in the middle of the cell body. The cation exchange membrane (6) divides the electrolytic cell (3) into an acid region and an alkali region. An anode (4) is provided in the acid region, and a cathode (5) is provided in the alkali region. Both the anode (4) and the cathode (5) are electrically connected to the multi-channel electrochemical workstation (1). The acid inlet is connected to the outlet of the acid region, and the alkali inlet is connected to the outlet of the alkali region. The electrolytic cell (3) is used to hold electrolyte and electrolyze it to produce acid solution at the anode (4) and alkaline solution at the cathode (5); The glass chromatography column (9) is filled with filter media (10). The acid outlet and the alkali outlet are respectively connected to the acid treatment equipment and the alkali treatment equipment.

2. The device for electrochemically driven ion exchange according to claim 1, characterized in that, Two filter membranes (11) are fixed inside the glass chromatography column (9), and a space for storing the filter material (10) is formed between the inner wall of the glass chromatography column (9) and the two filter membranes (11).

3. The device for electrochemically driven ion exchange according to claim 1, characterized in that, The acid inlet and the outlet of the acid region, as well as the alkali inlet and the outlet of the alkali region, are connected by a silicone tube (7). A peristaltic pump (8) is provided in the middle of the silicone tube (7), and the peristaltic pump (8) is used to drive the liquid flow.

4. The device for electrochemically driven ion exchange according to claim 1, characterized in that, Both the anode (4) and the cathode (5) are electrically connected to the multichannel electrochemical workstation (1) via wires (2).

5. The device for electrochemically driven ion exchange according to claim 1, characterized in that, The filter media (10) is a weak alkali resin.

6. The device for electrochemically driven ion exchange according to claim 1, characterized in that, The pH value of the acid solution is 2.

7. The device for electrochemically driven ion exchange according to claim 1, characterized in that, The pH value of the alkaline solution is 12-13.

8. A method for electrochemically driven ion exchange, using the apparatus for electrochemically driven ion exchange according to any one of claims 1-7, characterized in that, Includes the following steps: Turn on the multi-channel electrochemical workstation (1) so that the anode (4) and the cathode (5) electrolyze the electrolyte in the electrolytic cell (3) to form acid and alkali solutions; To increase the adsorption capacity of the filter media (10), the acid solution in the electrolytic cell (3) is passed into the glass chromatography column (9); When treating wastewater or source water, the influent is passed through the glass chromatography column (9) and purified by ion exchange through the filter media (10); When restoring the adsorption capacity of the filter media (10), the alkaline solution in the electrolytic cell (3) is passed into the glass chromatography column (9).

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