A method for removing and recovering heavy metal ions in water by using an intelligent adsorption electrode with controllable electric adsorption / desorption function

Abstract

The application relates to a method for removing and recycling heavy metal ions in water by using an intelligent adsorption electrode with controllable electric adsorption / desorption functions, and relates to the technical field of water treatment. The application aims to solve the problems of poor selectivity, small capacity, difficult control, difficult elution and resource recycling of traditional heavy metal pollution treatment technologies. The application develops a sulfidized polyacrylonitrile@titania foam ceramic intelligent adsorption electrode with controllable electric adsorption / desorption functions by using sulfur, polyacrylonitrile and titania foam ceramic as raw materials and through a simple preparation process. Relying on the unique disulfide bond / mercapto reversible conversion mechanism in the sulfidized polyacrylonitrile, the electrode potential can be accurately controlled, the heavy metal ions can be selectively removed, the safety of water quality can be ensured, the electrode can be regenerated easily, the heavy metals can be effectively recycled in the subsequent process, and a new possibility is provided for resource recycling. The application is suitable for large-scale water treatment applications.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, specifically, but not limited to, a method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function. Background Technology

[0002] With the acceleration of industrialization, heavy metal pollution from industries such as mining, electroplating, and circuit printing has had a significant impact on the aquatic environment. This pollution not only damages ecosystems and poses a serious risk to public health, but also deepens concerns about global resource scarcity. To address this challenge, the efficient removal of heavy metal ions from wastewater and the proper recycling and utilization of these resources have become crucial. Currently, numerous technical methods exist for addressing heavy metal pollution, such as extraction, oxidation, biodegradation, and adsorption. Among these, adsorption has attracted widespread attention from researchers due to its simplicity and low cost. However, traditional adsorbents such as activated carbon, biochar, and zeolite, due to their inherent structure and surface characteristics, still suffer from insufficient selectivity and challenges in optimizing adsorption and desorption efficiency. More importantly, the regeneration process of traditional adsorbents often relies on harmful chemicals such as strong acids or alkalis to provide the necessary energy to break the bond between the adsorbent and the adsorbate. This not only increases operational complexity but also introduces additional environmental risks. Therefore, the development of more intelligent and efficient adsorbents has become an urgent need in this field.

[0003] In the design of novel adsorbent materials, the ability to precisely control the kinetics of adsorption and desorption, such as electrostatic interactions, covalent bond formation, van der Waals forces, and hydrogen bonds, is crucial. Compared to traditional adsorbent materials, smart adsorbent materials can respond to changes in the external environment, adaptively adjusting their physical or chemical properties to more precisely control the adsorption or desorption process. This ability is quite similar to the characteristics exhibited by certain biological enzymes, such as lactate dehydrogenase, when binding ions. Inspired by this, the thiol groups in the active sites of some enzymes can form disulfide bonds under appropriate conditions, a feature that helps to selectively capture and release ions. Furthermore, thiol groups are believed to form stable chemical bonds with certain heavy metals, providing theoretical support for the development of smart adsorption systems that can respond to external stimuli. Based on this idea, disulfide-containing polyacrylonitrile sulfate (SPAN) is considered to have great potential for potentiometric response, as evidenced by its application in the battery field. Therefore, by designing a smart adsorption electrode with controllable electroadsorption / desorption function, using potential-responsive materials and through precise control of the electrode potential, highly selective adsorption and release of heavy metal ions in complex water bodies can be achieved, thereby significantly improving its recovery efficiency and reducing the risk of secondary pollution. Summary of the Invention

[0004] The purpose of this invention is to solve the problems of poor selectivity, small capacity, difficulty in control, high elution difficulty, and inability to recycle resources in traditional heavy metal pollution treatment technologies, and to provide an intelligent adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water.

[0005] This invention aims to utilize a potential-responsive intelligent adsorption electrode, which selectively captures heavy metal ions at a reduction potential and releases these ions at an oxidation potential. This technology not only overcomes the limitations of traditional non-selective adsorption but also solves problems such as poor selectivity, limited capacity, difficulty in elution, and inability to recover resources. This invention not only achieves reversible capture and release of heavy metal ions but also enables resource concentration and recovery.

[0006] This invention provides an intelligent adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water, characterized by the following steps:

[0007] I. Preparation of functional material vulcanized polyacrylonitrile: Sulfur powder, polyacrylonitrile, and ethanol were mixed in proportion, dried under vacuum, and the dried sample was heat-treated under inert gas conditions to obtain black vulcanized polyacrylonitrile powder, labeled as SPAN.

[0008] II. Preparation of intelligent adsorption electrode: The sulfurized polyacrylonitrile powder obtained in step one is added to an N-methyl-2-pyrrolidone solution containing polyvinylidene fluoride and magnetically stirred to obtain a uniformly mixed slurry; the titanium suboxide foam ceramic is immersed in the obtained slurry, and after standing for a period of time, it is taken out and dried to obtain an intelligent adsorption electrode with controllable electroadsorption / desorption function, labeled as SPAN@TiSO.

[0009] III. Application in the removal and recovery of heavy metal ions in water: The intelligent adsorption electrode SPAN@TiSO obtained in step II is added to the reaction tank. The SPAN@TiSO electrode is used as the working electrode, the high oxygen evolution potential electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode to form a three-electrode system. An electrolyte solution is added to the reaction tank. The heavy metal ions to be treated are added to the reaction tank. A specific voltage is applied between the intelligent adsorption electrode and the counter electrode to achieve the removal and recovery of heavy metal ions. Stirring is carried out during the treatment process.

[0010] Furthermore, the functional material, vulcanized polyacrylonitrile, is prepared by thermal polymerization: sulfur powder, polyacrylonitrile, and ethanol are mixed in a mass ratio of (5-3):1:(1-4), vacuum dried at 60-80℃ for 6-12 hours, and the dried sample is heat-treated under argon at 280-350℃ for 2-4 hours to obtain black vulcanized polyacrylonitrile powder.

[0011] Furthermore, the intelligent adsorption electrode is a titanium suboxide foam ceramic electrode loaded with sulfurized polyacrylonitrile, which is prepared by impregnation method: the titanium suboxide foam ceramic is immersed in a slurry with a mass ratio of sulfurized polyacrylonitrile to polyvinylidene fluoride of 9:1 to 7:3, left to stand for 60-120 min, and then vacuum dried at 60-80℃ for 8-10 h to finally obtain the intelligent adsorption electrode.

[0012] Furthermore, the loading amount of the vulcanized polyacrylonitrile on the titanium suboxide foam ceramic is 2–15 mg / cm³. -2 .

[0013] Furthermore, the reaction tank is divided into two chambers by an anion exchange membrane: the intelligent adsorption chamber is equipped with an intelligent adsorption electrode and a reference electrode, and the counter electrode chamber is equipped with a counter electrode.

[0014] Furthermore, the high oxygen evolution potential electrode is a titanium suboxide foam ceramic electrode.

[0015] Furthermore, the reaction tank contains an inert electrolyte including at least one of Na₂SO₄, NaNO₃, and NaClO₄, with an electrolyte concentration ranging from 1 to 30 mmol / L. -1 The pH value is 2–7.

[0016] Furthermore, the heavy metal ions to be treated are copper ions, which are added to the intelligent adsorption chamber at a concentration of 10–500 mg / L. -1 .

[0017] Furthermore, the applied voltage is 0–1V; when the applied voltage is 0–0.4V, the intelligent adsorption electrode adsorbs and removes heavy metal ions; when the applied voltage is 0.6–1V, the intelligent adsorption electrode releases and recovers the adsorbed heavy metal ions; the process is accompanied by stirring at a speed of 300–1200 rpm. -1 The processing time is 5 to 120 minutes.

[0018] The mechanism of this invention is as follows:

[0019] First, it's crucial to clarify that the most important part of this invention lies in the intelligent adsorption electrode. The unique disulfide bond / thiol reversible mechanism in potentiometrically responsive polyacrylonitrile plays a key role, enabling efficient adsorption of heavy metal ions upon applying a specific potential and rapid release upon changing the potential. Furthermore, by introducing porous titanium suboxide foam ceramic as a substrate, not only are the specific surface area and conductivity of the intelligent adsorption electrode increased, but a higher oxygen evolution potential is also provided, effectively mitigating oxygen evolution during the adsorption-desorption cycle and ensuring high efficiency in the treatment process. This invention chooses a titanium suboxide foam electrode because of its high oxygen evolution potential, which can solve the problem of reduced charge efficiency caused by oxygen or hydrogen evolution during electroadsorption / desorption. Secondly, to avoid the adverse effects of heavy metal ion deposition on the counter electrode, a dual-chamber reaction cell is designed and isolated using an anion exchange membrane.

[0020] The present invention has the following beneficial effects:

[0021] 1. This invention uses sulfur, acrylonitrile, and titanium suboxide foam ceramics as raw materials to prepare a smart adsorption electrode with controllable electroadsorption / desorption functions. The unique disulfide bond / thiol reversible mechanism in sulfurized polyacrylonitrile plays a key role, exhibiting good affinity for heavy metal ions and excellent electrochemical performance. The introduction of porous titanium suboxide foam ceramic substrate significantly increases the adsorption active sites of the adsorption electrode and improves its conductivity. By precisely controlling the electrode potential, not only can heavy metal ions be selectively removed, thus ensuring water quality safety, but these heavy metals can also be effectively recovered in subsequent processes, providing new possibilities for resource reuse.

[0022] 2. The intelligent adsorption electrode prepared by this invention exhibits excellent adsorption and desorption performance, maintaining a high adsorption capacity even in environments with low concentrations of heavy metal ions. Material characterization in Example 1 demonstrates that the combination of SPAN and TiSO provides a large number of effective adsorption sites; electrochemical testing in Example 1 reveals the interaction between the potential response function and heavy metal ions. Furthermore, electrode regeneration can be easily achieved simply by adjusting the potential, ensuring high stability even after multiple cycles. Compared to traditional adsorption technologies, this invention significantly reduces the consumption of chemical reagents and water resources, possessing significant environmental value and potential for treating heavy metal-contaminated wastewater.

[0023] 3. The electrode preparation method described in this invention is simple, and the raw materials used are environmentally friendly and low in cost, which gives it a significant advantage in large-scale production.

[0024] 4. The intelligent adsorption treatment device of the present invention is divided into two working zones, thereby avoiding the problem of heavy metal ions depositing on the electrodes during the treatment process. This improvement reduces energy consumption and increases current efficiency, making the treatment of heavy metal pollution more efficient, economical, and sustainable.

[0025] 5. This invention effectively solves the problems of poor selectivity, high regeneration difficulty, and difficulty in resource recovery in traditional adsorption technologies. Attached Figure Description

[0026] Figure 1 The flowchart illustrates the preparation process of the SPAN@TiSO smart adsorption electrode provided in this embodiment of the invention.

[0027] Figure 2 This is a schematic diagram of an intelligent adsorption electrode for the removal and recovery of heavy metal ions in water, provided in an embodiment of the present invention, wherein: 1. reaction tank; 2. regulated DC power supply; 3. magnetic stirrer; 4. anion exchange membrane; 5. counter electrode; 6. intelligent adsorption electrode; 7. Ag / AgCl reference electrode;

[0028] Figure 3 This is a scanning electron microscope image of the intelligent adsorption electrode in Embodiment 1 of the present invention;

[0029] Figure 4 The photoelectron spectrum of the intelligent adsorption electrode in Embodiment 1 of the present invention;

[0030] Figure 5 This is a graph showing the test results of the controllable electroadsorption / desorption function of the intelligent adsorption electrode in Example 1 of the present invention;

[0031] Figure 6 This is a graph showing the capture and release efficiency of heavy metal pollutants by different smart adsorption electrodes in Example 2 of the present invention;

[0032] Figure 7 This is a diagram illustrating the effect of the intelligent adsorption electrode in Embodiment 2 of the present invention on the concentration and enrichment of heavy metal pollutants.

[0033] Figure 8 This is a graph showing the effect of preparation temperature on electrode performance in Example 3 of the present invention;

[0034] Figure 9 This is a diagram showing the effect of applied voltage on electrode performance in Embodiment 4 of the present invention;

[0035] Figure 10 This is a graph showing the effect of competing metal ions on the heavy metal ion capture capacity in Example 5 of the present invention. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the spirit of the content disclosed in the present invention will be described in detail below. Any person skilled in the art, after understanding the embodiments of the present invention, can make changes and modifications based on the techniques taught in the present invention without departing from the spirit and scope of the present invention. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0037] The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0038] Example 1:

[0039] This embodiment describes a smart adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water, which is carried out according to the following steps:

[0040] I. Preparation of SPAN@TiSO Smart Adsorption Electrode: Sulfur powder, polyacrylonitrile, and ethanol were mixed at a mass ratio of 5:1:3 and vacuum dried at 60℃ for 8 hours. The dried sample was then heat-treated at 320℃ under argon for 2 hours to obtain black sulfurized polyacrylonitrile powder. Clean titanium suboxide foam ceramic was immersed in a slurry of sulfurized polyacrylonitrile and polyvinylidene fluoride at a mass ratio of 8:2, allowed to stand for 80 minutes, and then vacuum dried at 60℃ for 10 hours to obtain the SPAN@TiSO smart adsorption electrode.

[0041] 2. Add a 10 mM sodium sulfate electrolyte solution with a pH of 6.8 to the counter electrode chamber and the smart adsorption chamber of the dual-chamber reaction vessel, respectively. Then add 50 ppm copper ions to the smart adsorption chamber and stir until homogeneous. Under room temperature conditions, select the SPAN@TiSO electrode as the smart adsorption electrode and the porous titanium suboxide electrode as the counter electrode. Apply a potential of -0.1 to 1 V to the electrodes to realize the morphological transformation of sulfurized polyacrylonitrile at different potentials, thereby controlling the adsorption and release process of heavy metal ions.

[0042] Performance testing

[0043] 1. Preparation and structural characterization of SPAN@TiSO smart adsorption electrode

[0044] The SPAN@TiSO electrode in Example 1 was subjected to phase and structural characterization tests, and analyzed by scanning electron microscopy and photoelectron spectroscopy.

[0045] Scanning electron microscope image of the SPAN@TiSO electrode is shown below. Figure 3 As shown, the prepared vulcanized polyacrylonitrile powder exhibits an interconnected particle morphology. These particles are uniformly anchored on the surface of titanium suboxide, providing abundant active sites for accelerating the capture and release of heavy metal ions.

[0046] The photoelectron spectrum of the SPAN@TiSO electrode is as follows: Figure 4 As shown. In the C1s XPS spectrum, three different binding energies were found: 284.6 eV corresponds to sp... 2 Hybridized CC bonds; 285.4 eV corresponds to CS bonds; 286.6 eV corresponds to sp bonds. 2 Hybridized C=N bonds. The N 1s spectrum shows two peaks at 398.1 eV and 400.0 eV, corresponding to the N atoms in pyridine and pyrrole, respectively, further confirming the crosslinking during the sulfidation process. In the S2p spectrum, two main peaks are observed at 163.2 eV and 163.5 eV, corresponding to the CS and SS bonds, respectively.

[0047] 2. Potential response test

[0048] The controllable electroadsorption / desorption function of the intelligent adsorption electrode in Example 1 was tested and analyzed by cyclic voltammetry and electrochemical quartz crystal microbalance technology.

[0049] The test diagram of the controllable electroadsorption / desorption function of the intelligent adsorption electrode is shown below. Figure 5 As shown in Figure a, a distinct reversible redox peak is observed in the potential range of 0.25–0.4 V, confirming the redox transition of disulfide bonds / thiol groups. During the negative potential scan from 1.0 V to -0.1 V, the disulfide bonds within the electrode accept electrons and are reduced to the negatively charged thiol state. Furthermore, the current value increases significantly in the presence of copper ions, demonstrating the electrode's high sensitivity to copper ions. This enhanced sensitivity is related to the interaction between copper ions and the anionic groups in the potentiometric material, vulcanized polyacrylonitrile.

[0050] In the full-cycle experiment ( Figure 5 (b) The oxidation and reduction potentials were set to 0.2V and 0.8V, respectively. As the potentials alternated, the electrode mass exhibited periodic changes, further emphasizing the highly efficient regeneration capability of the smart adsorption electrode.

[0051] Example 2:

[0052] This embodiment describes a smart adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water, which is carried out according to the following steps:

[0053] I. Preparation of SPAN@TiSO Smart Adsorption Electrode: Sulfur powder, polyacrylonitrile, and ethanol were mixed at a mass ratio of 5:1:3 and vacuum dried at 60℃ for 8 hours. The dried sample was then heat-treated under argon at 320℃ for 2 hours to obtain black sulfurized polyacrylonitrile powder. Clean titanium suboxide foam ceramic was immersed in a slurry of sulfurized polyacrylonitrile and polyvinylidene fluoride at a mass ratio of 9:1, allowed to stand for 60 minutes, and then vacuum dried at 60℃ for 10 hours to obtain sulfurized polyacrylonitrile@titanium suboxide smart adsorption electrode. Polyacrylonitrile@titanium suboxide electrode was prepared under the same conditions.

[0054] 2. Add a 10 mM sodium sulfate electrolyte solution with a pH of 6.8 to the counter electrode chamber and the smart adsorption chamber of the dual-chamber reaction vessel. Then add 50 ppm copper ions to the smart adsorption chamber and stir until homogeneous. Under room temperature conditions, use TiSO₄, PAN@TiSO₄, and SPAN@TiSO₄ electrodes as smart adsorption electrodes, and a porous titanium suboxide electrode as the counter electrode, respectively. During the adsorption phase, apply a potential of 0.2 V to the electrodes for 30 min; during the release phase, apply a potential of 0.8 V to the electrodes for 30 min.

[0055] The diagram shows the capture and release efficiency of heavy metal pollutants. Figure 6 As shown in the figure, the adsorption performance of the TiSO and PAN@TiSO electrodes for copper ions is relatively average when the applied voltage is 0.2V. In contrast, the adsorption efficiency of the SPAN@TiSO electrode is as high as 96.2%, which is 13 times that of the PAN@TiSO electrode, fully demonstrating the excellent adsorption capacity of the SPAN@TiSO electrode. Furthermore, SPAN@TiSO can effectively adsorb the captured Cu ions at the oxidation potential. 2+ Released back into solution. By simply adjusting the voltage to 0.8V, the material released 98% of the captured Cu within 10 minutes. 2+ The release into the new copper-free electrolyte highlights the intelligent control characteristics of this electrode. Notably, this release process does not perfectly follow Langmuir kinetics, indicating that the release mechanism is not solely dependent on the concentration of the adsorbate. In fact, the rapid electrochemical reaction at the adsorption sites plays a decisive role, further validating the reversibility of the interaction between copper ions and disulfide bond sites.

[0056] Heavy metal pollutant concentration and enrichment diagram as shown in Figure 1 Figure 7 As shown, this system demonstrates excellent performance in concentrating copper species, achieving an average release efficiency of 98.4% even in a 10-fold concentrated solution. Furthermore, the release process remains stable under varying copper ion concentrations, further demonstrating the system's broad applicability and versatility.

[0057] Example 3:

[0058] This embodiment describes a smart adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water, which is carried out according to the following steps:

[0059] I. Preparation of SPAN@TiSO Smart Adsorption Electrodes: Sulfur powder, polyacrylonitrile, and ethanol were mixed at a mass ratio of 5:1:3 and vacuum dried at 60℃ for 8 hours. The dried samples were then heat-treated under argon conditions at 200℃, 260℃, 320℃, and 380℃ for 2 hours to obtain sulfurized polyacrylonitrile powder. Clean titanium suboxide foam ceramic was immersed in a slurry of sulfurized polyacrylonitrile and polyvinylidene fluoride at a mass ratio of 8:2, allowed to stand for 80 minutes, and then vacuum dried at 60℃ for 10 hours to obtain smart adsorption electrodes, which were named SPAN@TiSO-200, SPAN@TiSO-260, SPAN@TiSO-320, and SPAN@TiSO-380, respectively.

[0060] 2. A 10 mM sodium sulfate electrolyte solution with a pH of 6.8 was added to both the counter electrode chamber and the smart adsorption chamber of the dual-chamber reaction vessel. Then, 50 ppm copper ions were added to the smart adsorption chamber and stirred thoroughly. At room temperature, SPAN@TiSO electrodes prepared at different temperatures were selected as the smart adsorption electrodes, and a porous titanium suboxide electrode was used as the counter electrode. Potentials of 0.2 V and 0.8 V were applied to the electrodes to achieve the morphological transformation of sulfurized polyacrylonitrile at different potentials, thereby controlling the adsorption and release of heavy metal ions.

[0061] The effect of preparation temperature on electrode performance, such as Figure 8 As shown, the preparation temperature significantly affects the copper ion capture and release performance of the electrode. Under all conditions, the preparation temperature of 320℃ exhibits the best performance because the electrode achieves an optimal balance of structure, surface functional groups, and other properties at this temperature. Other preparation temperatures, especially 200℃, show significantly lower performance, possibly due to insufficient electrode activity or suboptimal structural characteristics.

[0062] Example 4:

[0063] This embodiment describes a smart adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water, which is carried out according to the following steps:

[0064] I. Preparation of SPAN@TiSO Smart Adsorption Electrode: Sulfur powder, polyacrylonitrile, and ethanol were mixed at a mass ratio of 5:1:3 and vacuum dried at 60℃ for 8 hours. The dried sample was then heat-treated at 320℃ under argon for 2 hours to obtain black sulfurized polyacrylonitrile powder. Clean titanium suboxide foam ceramic was immersed in a slurry of sulfurized polyacrylonitrile and polyvinylidene fluoride at a mass ratio of 9:1, allowed to stand for 80 minutes, and then vacuum dried at 60℃ for 10 hours to obtain the sulfurized polyacrylonitrile@titanium suboxide smart adsorption electrode.

[0065] 2. Add a 10mM sodium sulfate electrolyte solution with a pH of 6.8 to both the counter electrode chamber and the smart adsorption chamber of the dual-chamber reaction vessel. Then add 50ppm copper ions to the smart adsorption chamber and stir until homogeneous. At room temperature, use a SPAN@TiSO electrode as the smart adsorption electrode and a porous titanium suboxide electrode as the counter electrode. During the adsorption phase, apply potentials of 0.2V and -0.1V to the electrodes for 30 minutes; during the release phase, apply a potential of 0.8V to the electrodes for 10 minutes.

[0066] The effects of different applied potentials, such as Figure 9 As shown. Due to Cu 2+ The capture occurs in a reducing electrochemical environment, Cu 2+ To Cu 0 The reduction of Cu may affect the overall charge efficiency. It can be seen that at potentials of 0.2V and -0.1V, Cu... 0 The relative proportions were 0% and 39.6%, respectively. Meanwhile, the charge efficiency decreased from 87.8% at 0.2V to 65.1% at -0.1V, a drop of 22.7%. This data clearly indicates that at more negative potentials, Cu... 2+ Electrodeposition can negatively impact electrode performance. Therefore, the dual-chamber reaction cell design ensures that copper ions exist only within the intelligent adsorption cell, preventing their deposition on the counter electrode during continuous capture-release cycles, which is highly beneficial for improving charge efficiency.

[0067] Example 5:

[0068] This embodiment describes a smart adsorption electrode with controllable electroadsorption / desorption function for the removal and recovery of heavy metal ions in water, which is carried out according to the following steps:

[0069] I. Preparation of SPAN@TiSO Smart Adsorption Electrode: Sulfur powder, polyacrylonitrile, and ethanol were mixed at a mass ratio of 5:1:3 and vacuum dried at 60℃ for 8 hours. The dried sample was then heat-treated at 320℃ under argon for 2 hours to obtain black sulfurized polyacrylonitrile powder. Clean titanium suboxide foam ceramic was immersed in a slurry of sulfurized polyacrylonitrile and polyvinylidene fluoride at a mass ratio of 9:1, allowed to stand for 80 minutes, and then vacuum dried at 60℃ for 10 hours to obtain the sulfurized polyacrylonitrile@titanium suboxide smart adsorption electrode.

[0070] 2. Add a 10 mM sodium sulfate electrolyte solution with a pH of 6.8 to the counter electrode chamber and the smart adsorption chamber of the dual-chamber reaction vessel. Then add a solution containing 0.78 mmol / L to the smart adsorption chamber. -1 Na + K + Mg 2+ Ca 2+ Zn 2+ and Cu 2+ The multi-component solution was stirred until homogeneous. At room temperature, a SPAN@TiSO electrode was used as the smart adsorption electrode, and a porous titanium suboxide electrode was used as the counter electrode. During the adsorption phase, a potential of 0.2V was applied to the electrode for 30 minutes; during the release phase, a potential of 0.8V was applied to the electrode for 10 minutes.

[0071] The effect of competing metal ions on the heavy metal ion capture capacity is as follows: Figure 10 As shown, the electrode's ability to capture copper ions in a mixed solution is only slightly reduced compared to its performance in a single copper ion environment. However, the capture of other competing metal ions is significantly affected in the mixed solution, with a copper ion selectivity factor of 22:1 observed at 0.2 V, further highlighting its high selectivity for copper ions.

Claims

1. A method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function, characterized in that... It is done in the following steps: I. Functional material vulcanized polyacrylonitrile is prepared by thermal polymerization: sulfur powder, polyacrylonitrile, and ethanol are mixed in a mass ratio of (5~3):1:(1~4), and vacuum dried at 60-80℃ for 6-12 h. The dried sample is then heat-treated under argon at 280-350℃ for 2-4 h to obtain black vulcanized polyacrylonitrile powder; labeled as SPAN. II. Preparation of the intelligent adsorption electrode: The sulfurized polyacrylonitrile powder obtained in step one is added to an N-methyl-2-pyrrolidone solution containing polyvinylidene fluoride and magnetically stirred to obtain a uniformly mixed slurry; the titanium suboxide foam ceramic is immersed in the obtained slurry, allowed to stand, and then removed and dried to obtain an intelligent adsorption electrode with controllable electroadsorption / desorption function, labeled as SPAN@TiSO; the intelligent adsorption electrode is a titanium suboxide foam ceramic electrode loaded with sulfurized polyacrylonitrile, prepared by the impregnation method: the titanium suboxide foam ceramic is immersed in the slurry at a mass ratio of 9:1 to 7:3, allowed to stand for 60-120 min, and then vacuum dried at 60-80℃ for 8-10 h to finally obtain the intelligent adsorption electrode with controllable electroadsorption / desorption function. III. Application in the removal and recovery of heavy metal ions in water: The intelligent adsorption electrode SPAN@TiSO obtained in step II is added to the reaction tank. The SPAN@TiSO electrode is used as the working electrode, the high oxygen evolution potential electrode is used as the counter electrode, and Ag / AgCl is used as the reference electrode to form a three-electrode system. An electrolyte solution is added to the reaction tank. The heavy metal ions to be treated are added to the reaction tank. A specific voltage is applied between the intelligent adsorption electrode and the counter electrode to achieve the removal and recovery of heavy metal ions. Stirring is carried out during the treatment process.

2. The method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function according to claim 1, characterized in that... In step two, the loading amount of vulcanized polyacrylonitrile on the titanium suboxide foam ceramic is 2~15 mg·cm³. -2 .

3. The method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function according to claim 1, characterized in that... In step three, the reaction tank is divided into a smart adsorption chamber and a counter electrode chamber by an anion exchange membrane: the smart adsorption chamber is equipped with a smart adsorption electrode and a reference electrode, and the counter electrode is placed in the counter electrode chamber.

4. The method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function according to claim 1, characterized in that... In step three, the high oxygen evolution potential electrode is a sub-titanium oxide foam ceramic electrode.

5. A method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function, as described in claim 1, characterized in that... In step three, the reaction tank contains an inert electrolyte, which is at least one of Na₂SO₄, NaNO₃, and NaClO₄, with a concentration ranging from 1 to 30 mmol·L⁻¹. -1 The pH value is 2-7.

6. A method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function, as described in claim 1, is characterized in that... In step three, the heavy metal ions to be treated are copper ions.

7. A method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function, as described in claim 1 or 6, characterized in that... The concentration of the heavy metal ions is 10~500 mg·L. -1 .

8. A method for removing and recovering heavy metal ions in water using an intelligent adsorption electrode with controllable electroadsorption / desorption function, as described in claim 1, characterized in that... In step three, a voltage of 0~0.4 V is applied, and the intelligent adsorption electrode adsorbs and removes heavy metal ions; An applied voltage of 0.6–1 V is used to release and recover adsorbed heavy metal ions using an intelligent adsorption electrode; the process is accompanied by stirring at a speed of 300–1200 r·min. -1 The processing time is 5~120 min.

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