A method for preparing mesoporous high-entropy alloys from electroplating wastewater based on electrodeposition-thermal pore-forming and its application

Abstract

This invention discloses a method for preparing mesoporous high-entropy alloys from electroplating wastewater based on electrodeposition-thermal pore-forming and its application. Using electroplating wastewater containing at least five metal ions (zinc, iron, cobalt, nickel, copper, chromium, and manganese) as raw material, a modified titanium-based composite electrode is used as the cathode, and a metal-based oxide conductive electrode as the anode. The method involves anodic oxidation to break down and dissociate complexed metal ions, followed by cathodic reduction to achieve simultaneous and synergistic deposition of multi-metal ions, resulting in a titanium-based electrode loaded with multi-metal precursors. Subsequently, high-temperature heat treatment is performed in an inert atmosphere, utilizing the volatilization and migration of zinc components inherent in the wastewater at high temperatures to construct a mesoporous structure in situ within the material. Simultaneously, this drives solid solution transformation of the multi-metal system, forming a stable mesoporous high-entropy alloy. This mesoporous high-entropy alloy material exhibits excellent performance in the electrocatalytic degradation of recalcitrant organic pollutants in water, achieving the integrated construction of high-value recovery and high-performance mesoporous high-entropy alloy materials.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a method for preparing mesoporous high-entropy alloys from multimetals recovered from electroplating wastewater based on electrodeposition-thermal pore formation, and its application. Background Technology

[0002] The electroplating industry generates large amounts of wastewater containing various metal ions such as Zn, Fe, Co, Ni, Cu, Cr, and Mn during production. Direct discharge of this wastewater without treatment will cause serious environmental pollution and waste metal resources. Existing treatment methods, such as chemical precipitation, ion exchange, and membrane separation, can remove pollutants, but they suffer from high treatment costs, low resource utilization, and secondary pollution.

[0003] Meanwhile, high-entropy alloys, as multi-component materials composed of five or more metallic elements, exhibit excellent performance in electrocatalysis due to their lattice distortion effect, slow diffusion effect, and synergistic catalytic effect. However, traditional high-entropy alloys typically rely on high-purity metal raw materials and are prepared through methods such as smelting or powder metallurgy, which suffers from high cost, complex processes, and difficulty in constructing porous structures. Furthermore, the specific surface area and pore structure of catalytic materials have a significant impact on their performance. The dense structure and limited active sites of traditional high-entropy alloys restrict their application in electrocatalysis. Therefore, developing a method that can directly construct high-entropy alloys using metal ions from wastewater while simultaneously controlling the pore structure is of great significance for achieving pollution control and resource utilization.

[0004] The prior art CN118002144A discloses a method for preparing copper-based high-entropy alloy Fenton-like catalysts based on controllable electrodeposition. By controlling the electrodeposition of elements such as Cu, Fe, Co, Ni, and Zn on the electrode, a copper-based high-entropy micro / nano alloy catalyst with a multi-level dendritic structure is prepared. A pure copper electrode is used as the cathode and graphite as the anode. Electrodeposition is performed using an electrolyte containing multiple metal ions to obtain the copper-based high-entropy alloy Fenton-like catalyst. This application uses an electrodeposition method to prepare high-entropy alloys, but the electrolyte is artificially prepared and is not electroplating wastewater.

[0005] CN115763840A discloses a method for preparing a mesoporous high-entropy alloy catalyst and its application. By synthesizing the mesoporous high-entropy alloy catalyst in one step in the KIT-6 channel, the problem of synthesizing mesoporous high-entropy intermetallic compounds is solved. It involves mesoporous high-entropy alloys, but does not involve wastewater recycling pathways.

[0006] CN114836714A discloses a FeCoNiMn high-entropy alloy thin film, its preparation method, and its application. The FeCoNiMn high-entropy alloy thin film is prepared by radio frequency magnetron sputtering and used for electrocatalytic oxidation degradation of organic pollutants, which solves the problem that existing catalysts cannot effectively degrade them. The high-entropy alloy thin film is prepared by radio frequency magnetron sputtering and used for electrocatalytic degradation of organic matter. The high-entropy alloy is used for electrocatalytic degradation, but the preparation method is completely different from that of this application. Summary of the Invention

[0007] Technical Problems Solved: This invention addresses the problems in existing technologies, such as the difficulty in recovering heavy metals from electroplating wastewater and low resource utilization, high cost and small specific surface area in the preparation of high-entropy alloys, making it difficult to directly construct high-performance catalytic materials from wastewater, and the limited catalytic performance due to poor porosity. It provides a method for recovering multiple metals from wastewater and constructing mesoporous high-entropy alloys. This method combines electrodeposition and thermal pore formation to achieve high-value recovery of multiple metal resources and synergistic regulation of the high-entropy alloy material structure, thereby obtaining mesoporous high-entropy alloy materials with high specific surface area and excellent electrocatalytic performance.

[0008] Purpose of the invention: This application provides a method for preparing mesoporous high-entropy alloys based on electrodeposition-thermal pore-forming recovery of multi-metals from electroplating wastewater and its application. This method can directly utilize the complex multi-metal ion system in electroplating wastewater to simultaneously achieve deep purification of wastewater, high-value recovery of multi-metals, and integrated construction of mesoporous high-entropy alloys. It has important practical significance and scientific value for environmental protection and resource recycling.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a method for preparing mesoporous high-entropy alloys based on electrodeposition-thermal pore-forming recovery of multimetals from electroplating wastewater, specifically including the following steps: The first step is to prepare a multi-metal precursor by electrodeposition: a modified titanium-based composite electrode is used as the cathode, a metal-based oxide conductive electrode is used as the anode, and electroplating wastewater containing at least four transition metal ions from Zn and Fe, Co, Ni, Cu, Cr, and Mn is used as the electrolyte. Constant voltage electrodeposition is performed. During the electrodeposition process, an oxidation-complex breaking reaction occurs at the anode, which dissociates the complexed metal ions in the wastewater into free metal ions. Simultaneous synergistic reduction deposition of multi-metal ions occurs at the cathode, and a titanium-based electrode material loaded with multi-metal precursors is obtained on the surface of the titanium-based cathode. The second step is to prepare a mesoporous high-entropy alloy by high-temperature heat treatment: the titanium-based electrode material loaded with the multi-metal precursor is subjected to high-temperature heat treatment in an inert atmosphere. The zinc component in the electroplating wastewater volatilizes and migrates at high temperature, forming a mesoporous structure in situ inside the material. At the same time, the multi-metal component undergoes solid solution transformation to form a mesoporous high-entropy alloy.

[0010] As a preferred technical solution of this application, the relative deviation of the radius of the transition metal ions and zinc ions is ≤15%, and the metal ions contained in the electroplating wastewater are six kinds: Zn, Fe, Co, Ni, Cu and Cr.

[0011] As a preferred technical solution of this application, the modified titanium-based composite electrode is a titanium mesh or titanium plate with surface modification treatment, used to regulate the pH and ion transport at the cathode interface; the metal-based oxide conductive electrode is an insoluble inert anode, which does not introduce external metal impurities during the electrodeposition process.

[0012] As a preferred technical solution of this application, in the first step, the electrodeposition process parameters are: anode-cathode distance 1~3cm, applied voltage 1~10V, electrodeposition at room temperature for 1~5h.

[0013] As a preferred technical solution of this application, the anode and cathode are spaced 2 cm apart, a voltage of 5V is applied, and electrodeposition is carried out at room temperature for 2 hours. During the electrodeposition process, an oxidation-complexation reaction occurs at the anode: the complexed metal ions in the wastewater dissociate under the action of anodic oxidation, releasing free metal ions; at the same time, a synchronous synergistic reduction deposition of multiple metal ions occurs at the cathode. Since the titanium-based cathode has been modified, it can regulate the interface pH and ion transport, promote the uniform co-deposition of multiple metal ions on the surface of the titanium mesh, and form a uniform and firmly bonded multi-metal precursor layer; the resulting product is the titanium-based electrode material loaded with multi-metal precursors.

[0014] As a preferred technical solution of this application, in the second step, the high-temperature heat treatment process parameters are as follows: under argon protection, the temperature is raised to 900~1200℃ at a heating rate of 2~10℃ / min, held for 1~48h, and then naturally cooled with the furnace.

[0015] As a preferred technical solution of this application, the temperature is raised to 900~950℃ at a heating rate of 5℃ / min and held for 6~18h. During the high-temperature heat treatment, the zinc component in the precursor, due to its low boiling point and high volatility, volatilizes and migrates to the outside of the material, leaving pores in the original positions, thereby constructing a uniform mesoporous structure in situ inside the material. At the same time, the remaining Fe, Co, Ni, Cu, Cr, and Mn metal elements in the precursor undergo atomic interdiffusion and solid solution reaction at high temperature to form a high-entropy alloy with a single solid solution phase structure.

[0016] As a preferred embodiment of this application, the zinc component originates solely from the electroplating wastewater itself, requiring no additional pore-forming agent or zinc source. After high-temperature heat treatment, the zinc component is essentially volatilized and removed, with a residual amount of less than 1 wt.%. The mesoporous high-entropy alloy material obtained by this method possesses a uniformly distributed mesoporous structure and a specific surface area of ​​50~200 m². 2 / g, consisting of a high-entropy solid solution phase formed by five or more metallic elements, and containing no carbon-based support.

[0017] An application of a mesoporous high-entropy alloy material prepared by any of the above methods in the electrocatalytic degradation of organic pollutants, wherein the mesoporous high-entropy alloy material is used as the anode and a titanium sheet is used as the cathode to electrocatalytically degrade water containing organic pollutants under a constant current electric field.

[0018] As a preferred technical solution of this application, the organic pollutant is selected from one or more of florfenicol, tetracycline, norfloxacin, and sulfamethoxazole; the constant current is 1~10 A, the degradation time is 30~120 min, and the degradation rate can reach more than 98%.

[0019] The technical principle of this invention is as follows: It utilizes anodic complex breaking and cathode co-deposition to achieve the simultaneous recovery of five or more metals from electroplating wastewater. The strong oxidizing power of the insoluble anode breaks down the stable complexes formed between metal ions and organic ligands in the electroplating wastewater, releasing the bound metal ions and providing a free ion source for subsequent co-deposition. The modified titanium-based composite cathode provides a suitable electrode potential and interfacial microenvironment, enabling multiple metal ions at different standard electrode potentials to overcome hydrogen evolution interference and achieve simultaneous reduction and uniform co-deposition. The invention also utilizes native Zn from the electroplating wastewater. 2+ The components serve as endogenous templates, eliminating the need for any external pore-forming agents. High-temperature volatilization constructs a mesoporous structure. Since Zn originates from the wastewater itself, it does not incur additional costs or introduce impurities. The multi-component high-temperature solid solution forms a high-entropy alloy, possessing both high specific surface area and abundant active sites, achieving synergy between pollution control and resource utilization. Simultaneously with Zn volatilization, other metal atoms undergo sufficient diffusion and lattice rearrangement at high temperatures, forming a high-entropy solid solution. The single-phase solid solution structure of the high-entropy alloy exhibits thermodynamic stability, and due to lattice distortion and multi-element synergy, it displays excellent electrocatalytic activity.

[0020] The method for preparing mesoporous high-entropy alloys based on electrodeposition-thermal pore-forming to recover multimetals from electroplating wastewater and its application described in this application have the following technical advantages compared with the prior art: 1. By combining anodic oxidation and cathode co-deposition, efficient dissociation of complexed heavy metals and simultaneous recovery of multiple metals can be achieved, improving the depth of wastewater treatment and resource utilization. Through the synergy of anodic oxidation and cathode co-deposition, five or more metal ions in electroplating wastewater can be recovered simultaneously, with a recovery rate of over 95%. 2. Using zinc metal ions contained in electroplating wastewater as an endogenous template agent, high-temperature volatilization creates pores in situ, avoiding the impurity pollution and additional costs caused by introducing external template agents in traditional methods. No external pore-forming agent is required, impurities are avoided, the process is simplified, and the preparation cost is reduced. 3. Mesoporous structure construction and high-entropy alloy phase formation are achieved simultaneously through one-step heat treatment. The material has a uniform pore structure, high specific surface area, and excellent electrocatalytic activity and cycle stability. When used for the electrocatalytic degradation of antibiotics, the degradation rate can reach more than 98% within 30 to 120 minutes under constant current conditions of 1 to 10 A, and the activity decay is less than 5% after 5 cycles. 4. The process uses conventional equipment and operating conditions, the parameters are easy to control, there is no harsh reaction environment, and it has the conditions for industrial scale-up and continuous production. It can be completed with only electrodeposition and one-step heat treatment, without the need for complex equipment. The raw material is industrial wastewater, and the production cost is far lower than that of traditional high-entropy alloy preparation methods. 5. By directionally converting heavy metal pollutants in electroplating wastewater into high-performance electrocatalytic materials, pollutant reduction and resource value enhancement can be achieved simultaneously, resulting in significant synergistic environmental and economic benefits. This transforms waste into treasure, solving environmental pollution problems while creating economic value. Attached Figure Description

[0021] Figure 1 This invention describes the preparation of FeCoCrNiCu-ZnO and FeCoCrNiCu-Zn under different endogenous zinc content conditions. 2.0 and FeCoCrNiCu-Zn 2.5 SEM images of the samples and elemental mapping diagrams of Fe, Co, Cr, Ni, and Cu; the SEM images show that each sample has a regular spherical particle morphology, and the elemental mapping diagrams show that Fe, Co, Cr, Ni, and Cu are uniformly distributed inside the particles, indicating that the electrodeposition-thermal treatment process can achieve uniform synergistic deposition and solid solution transformation of multiple metal elements. Figure 2 The XRD patterns of high-entropy alloy materials prepared by electroplating wastewater systems with different internal Zn contents according to the present invention are shown. Each sample shows characteristic diffraction peaks at approximately 43.5°, 50.7° and 74.6°, which correspond to the (111), (200) and (220) crystal planes of the FCC solid solution phase, respectively. No obvious metallic element or intermetallic compound impurity peaks are shown, indicating that the multi-metal components form a single high-entropy solid solution structure after high-temperature heat treatment. Figure 3 This invention presents the N2 adsorption-desorption isotherm and BJH pore size distribution diagram of the mesoporous high-entropy alloy material obtained by this invention; the material exhibits a typical type IV adsorption-desorption curve with a significant hysteresis loop, and has a specific surface area of ​​132 m². 2 / g, with an average pore size of about 28nm, and the pore size is mainly concentrated in the range of 20~50 nm, which proves that the material has a well-developed mesoporous structure; Figure 4 The figure shows the removal effect of zinc nitrate at different ratios on 5 mg / L florfenicol solution according to the present invention. Detailed Implementation

[0022] The present invention will now be explained in more detail with reference to specific embodiments and comparative examples. It is worth noting that the embodiments and comparative examples listed are not all implementations, but only a part of them. Parts not explained in detail in the specific embodiments described in the invention are consensus among those skilled in the art.

[0023] Example 1: A method for preparing mesoporous high-entropy alloys by recovering multi-metals from electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: Step 1: The titanium-based material, such as titanium mesh, is ultrasonically cleaned sequentially with ethanol, acetone, and deionized water, and then placed in a 1 mol / L HCl solution at 80°C for 30 min. After drying, it is ready for use as a negatively modified titanium-based composite electrode. Step 2: Using electroplating wastewater containing Zn, Fe, Co, Ni, Cu, Cr, and Mn metal ions as the electrolyte, wherein Zn... 2+ 120 mg / L, Fe 3+ 85 mg / L, Co 2+ 45 mg / L, Ni 2+ 60 mg / L, Cu 2+ 35 mg / L, Cr 3+ The wastewater had a concentration of 50 mg / L, a total metal ion concentration of approximately 395 mg / L, a pH of 4.5, and a COD of approximately 800 mg / L. Using a negatively modified titanium-based composite electrode as the cathode and a titanium-based oxide conductive electrode as the anode, the electrode spacing was controlled at 2 cm, and a constant voltage of 5V was applied for electrodeposition for 2 hours. During the electrodeposition process, bubbles (oxygen) were continuously generated on the anode surface, and a gray-black metal layer was gradually deposited on the cathode surface, completing the anodic oxidation complex breaking and cathode multi-metal synergistic co-deposition. After the deposition was completed, the cathode was removed, rinsed with deionized water, and vacuum dried at 60℃ for 2 hours to obtain a titanium mesh electrode loaded with multi-metal precursors. Step 3: The titanium mesh electrode loaded with multi-metal precursors is placed in an inert atmosphere of high-purity argon and heated to 900℃ at a rate of 5℃ / min. It is then held at that temperature for 12 hours and then naturally cooled to room temperature with the furnace. The Zn metal ion component contained in the electroplating wastewater is used as an endogenous template agent. It volatilizes and migrates in a directional manner at high temperature, constructing a mesoporous structure in situ inside the material. At the same time, it drives the multi-metal component to undergo solid solution transformation, forming a structurally stable mesoporous high-entropy alloy material.

[0024] Characterization of the obtained material: SEM showed that the material surface has abundant mesoporous structure with pore sizes of approximately 20–50 nm; EDS elemental analysis showed that the relative atomic ratios of Fe, Co, Ni, Cu, and Cr were 21:18:19:17:22 (Zn residue <0.5%); XRD pattern showed a single FCC solid solution structure with no impurities of elemental metals or intermetallic compounds; BET specific surface area was 132 m². 2 / g, average pore size 28 nm.

[0025] The mesoporous high-entropy alloy material prepared by the method is used in the electrocatalytic degradation of organic pollutants. Using the mesoporous high-entropy alloy material as the anode and a titanium sheet as the cathode, the organic pollutants are electrocatalytically degraded in water bodies under a constant current electric field. The organic pollutants are selected from one or more of florfenicol, tetracycline, norfloxacin, and sulfamethoxazole; the constant current is 1-10 A, the degradation time is 30-120 min, and the degradation rate can reach over 98%.

[0026] Example 2: A method for preparing mesoporous high-entropy alloys by recovering multimetals from electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, with the only difference being that the electrodeposition voltage is adjusted to 3V in the second step. During the subsequent high-temperature annealing process, the mesoporous structure is also created in situ through the high-temperature volatilization and migration of the zinc component, completing the multi-metal solid solution phase transformation to obtain the mesoporous high-entropy alloy material. All other process parameters and steps remain unchanged. The BET specific surface area is measured to be 95 m². 2 / g, with an average pore size of 24 nm, and a degradation rate of 91.3% for 5 mg / L florfenicol solution after 90 min.

[0027] Example 3: A method for preparing mesoporous high-entropy alloys by recovering multimetals from electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, with the only difference being that the electrodeposition voltage in the second step is adjusted to 7 V. During the subsequent high-temperature annealing process, the mesoporous structure is constructed and multi-metal solid solution phases are formed based on the self-templating effect of the zinc component, resulting in a mesoporous high-entropy alloy material. All other process parameters and steps remain unchanged. The BET specific surface area is measured to be 10⁸ m². 2 / g, with an average pore size of 26 nm, and a degradation rate of 94.7% for 5 mg / L florfenicol solution after 90 min.

[0028] Comparison of SEM morphology of deposited products under different voltages revealed that the deposited layer was thinner and less complete at 3V, while the multi-metal deposited layer was continuous and uniform at 5V, and local agglomeration occurred at 7V. EDS results showed that the distribution of Fe, Co, Ni, Cu and Cr elements was most uniform at 5V, and the preferred electrodeposition voltage was 5V.

[0029] Example 4: A method for preparing mesoporous high-entropy alloys by recovering multimetals from electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, except that the electrodeposition time in the second step is adjusted to 1 hour, followed by high-temperature annealing. This allows for the in-situ formation of a mesoporous structure through the high-temperature volatilization and migration of the zinc component, completing the multi-metal solid solution transformation and yielding a mesoporous high-entropy alloy material. All other process parameters and steps remain unchanged. The BET specific surface area is measured to be 86 m². 2 / g, with an average pore size of 22 nm, and a degradation rate of 89.5% in 5 mg / L florfenicol solution after 90 min.

[0030] Example 5: A method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, with the only difference being that the electrodeposition time in the second step is adjusted to 3 hours, followed by high-temperature annealing to achieve pore formation of the zinc component and multi-metal solid solution phase transformation, resulting in a mesoporous high-entropy alloy material. All other process parameters and steps remain unchanged. The BET specific surface area was measured to be 118 m². 2 / g, with an average pore size of 30 nm, and a degradation rate of 95.2% for 5 mg / L florfenicol solution after 90 min.

[0031] Example 6: A method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: The operation steps in this embodiment are completely the same as those in Embodiment 1, the only difference being that the annealing temperature in the third step is adjusted to 850 ℃. Because the temperature is lower than the boiling point of Zn, zinc volatilization is insufficient, the mesoporous structure is poorly developed, and the specific surface area is only 45 m². 2 / g. The specific surface area of ​​BET was measured to be 45 m². 2 / g, with an average pore size of 16 nm, and a degradation rate of 76.8% for 5 mg / L florfenicol solution after 90 min.

[0032] Example 7: A method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore-forming and its application, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, with the only difference being that: in the third step, the annealing temperature is adjusted to 950 ℃. Under high-temperature conditions, the zinc component acts as an internal template to achieve mesoporous pore formation, simultaneously completing the multi-metal solid solution transformation to obtain a mesoporous high-entropy alloy material. All other process parameters and treatment steps remain unchanged, and the specific surface area of ​​the obtained product is 156 m². 2 / g, degradation rate 99%.

[0033] XRD patterns at different temperatures showed that the sample heat-treated at 600℃ still had impurity peaks of polymetallic oxides or intermetallic compounds, while the impurity peaks of the sample at 850℃ were significantly reduced but the solid solution was incomplete. When the temperature was raised to 900~950℃, only the characteristic peaks of the FCC solid solution phase were retained, indicating that high temperature promoted the interdiffusion of polymetallic atoms and the formation of high-entropy solid solution phase.

[0034] Example 8: A method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore-forming and its application, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, with the only difference being that the annealing holding time in the third step is adjusted to 6 hours. By extending the holding time, the zinc component fully volatilizes and migrates to form a uniform mesoporous structure, and the multi-metal system fully dissolves to form a high-entropy alloy. All other process parameters and steps remain unchanged. The BET specific surface area was measured to be 88 m². 2 / g, with an average pore size of 23 nm, and a degradation rate of 88.9% in 5 mg / L florfenicol solution after 90 min.

[0035] Example 9: A method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore-forming and its application, specifically including the following steps: This embodiment is identical to Embodiment 1 in terms of operation steps, except that the annealing holding time in the third step is adjusted to 18 hours. This prolonged high-temperature treatment promotes deep migration and volatilization of the zinc component and full formation of the mesoporous structure, while ensuring complete solid solution of the multi-metal components, resulting in a mesoporous high-entropy alloy material. All other process parameters and steps remain unchanged. The BET specific surface area is measured to be 145 m². 2 / g, with an average pore size of 34 nm, and a degradation rate of 98.1% for 5 mg / L florfenicol solution after 90 min.

[0036] The results of pore size distribution under different heat preservation times show that the pore size distribution is the most concentrated and the element distribution is the most uniform when heat preservation is 12 h, and the overall performance is the best.

[0037] Example 10: A method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore-forming and its application, specifically including the following steps: This embodiment is completely identical to Embodiment 1 in terms of operation steps, with the only difference being that the anode-cathode distance is adjusted to 1.5 cm in the second step. Subsequent high-temperature annealing, relying on the zinc component for self-templating pore formation and multi-metal solid solution transformation, yields a mesoporous high-entropy alloy material. All other process parameters and steps remain unchanged. The BET specific surface area is measured to be 110 m². 2 / g, with an average pore size of 27nm, and a degradation rate of 93.6% for 5 mg / L florfenicol solution after 90 min.

[0038] Comparative Example 1: A method for preparing mesoporous high-entropy alloys from electroplating wastewater based on electrodeposition-thermal pore-forming, specifically including the following steps: The operation steps of this comparative example are basically the same as those of Example 1, except that the third step of high-temperature annealing is omitted. Because high-temperature heat treatment is not performed, the zinc component in the system cannot volatilize and migrate to form a mesoporous structure, and the multi-metal component cannot complete the solid solution phase transformation, only producing a multi-metal deposition precursor material. The remaining process parameters and treatment steps remain unchanged. The BET specific surface area was measured to be 18 m². 2 / g, with an average pore size of less than 10 nm, XRD showed mixed peaks of multi-metal oxides and elemental metals, and a degradation rate of 32.4% for 5 mg / L florfenicol solution after 90 min.

[0039] Comparative Example 2 illustrates a method for preparing mesoporous high-entropy alloys from electroplating wastewater using an electrodeposition-thermal pore-forming process. The method includes the following steps: The operation steps of this comparative example are essentially the same as those in Example 1, except that in the second step, electroplating wastewater without Zn metal ions is used as the electrolyte, and the raw material system lacks zinc components as a pore-forming template. Subsequent high-temperature treatment cannot achieve in-situ construction of the mesoporous structure and is difficult to form a stable high-entropy solid solution. All other process parameters and treatment steps remain unchanged. Testing revealed that the BET specific surface area is only 12 m². 2 / g, with an average pore size of less than 8 nm, XRD showed that the multi-metals did not completely form a single solid solution phase, and the degradation rate of 5 mg / L florfenicol solution was 41.2% after 90 min.

[0040] Comparative Example 3 illustrates a method for preparing mesoporous high-entropy alloys from multi-metal recovery in electroplating wastewater based on electrodeposition-thermal pore formation. The method includes the following steps: The operation steps of this comparative example are basically the same as those in Example 1, except that the annealing temperature in the third step is set to 600 °C. Under this temperature condition, the zinc component's volatilization and migration are insufficient, making it impossible to form a well-developed mesoporous structure. The solid solution transformation of the multi-metal system is incomplete, making it difficult to obtain a structurally stable mesoporous high-entropy alloy. All other process parameters and treatment steps remain unchanged. The BET specific surface area was measured to be 28 m². 2 / g, with an average pore size of 12 nm, and a degradation rate of 38.6% in 5 mg / L florfenicol solution after 90 min.

[0041] Comparative Example 4 illustrates a method for preparing mesoporous high-entropy alloys from electroplating wastewater based on electrodeposition-thermal pore-forming. The method includes the following steps: The operational steps of this comparative example are basically the same as those in Example 1, except that in the second step, anodic complex breaking treatment is not performed during electrodeposition; only cathodic deposition is performed directly. All other process parameters and steps remain unchanged. Testing showed that the metal recovery rate was less than 40%, and the BET specific surface area was 9 m². 2 / g, the degradation rate of 5 mg / L florfenicol solution for 90 min was 9.8%.

[0042] Performance Verification: The materials prepared in Example 1 and Comparative Examples 1-4 were used as anodes, and titanium sheets were used as cathodes. A 5 mg / L florfenicol solution was treated under the same constant current electrocatalytic conditions. Changes in specific surface area, average pore size, 90-min degradation rate, and apparent rate constant k were investigated. The results showed that Example 1 possessed a higher specific surface area, a well-developed mesoporous structure, and a single-phase high-entropy solid solution structure, thus exhibiting the highest degradation rate and efficiency.

[0043] The N2 adsorption-desorption and BJH pore size distribution results show that the material in Example 1 exhibits a typical type IV isotherm with a significant hysteresis loop, and the pore size is mainly distributed in the range of 20~50 nm. The adsorption amounts of Comparative Examples 1, 2 and 3 are significantly reduced, the hysteresis loop is not obvious or the pore size distribution is narrower, indicating that no heat treatment, lack of endogenous Zn or insufficient heat treatment temperature are not conducive to the formation of mesoporous structures.

[0044] XRD results showed that the heat-treated product of Example 1 exhibited characteristic peaks of FCC high-entropy solid solution phase at approximately 43.5°, 50.7°, and 74.6°, corresponding to the (111), (200), and (220) crystal planes, respectively. In Comparative Examples 1 and 3, there were still metal oxide or intermetallic compound impurity peaks. In Comparative Example 2, the solid solution phase was not fully formed due to the lack of Zn-induced pore structure evolution and element rearrangement process.

[0045] Table 1 Summary of Results of Process Parameter Optimization Examples .

[0046] Table 2 Comparison of material structure and degradation performance between the examples and comparative examples .

[0047] The above results demonstrate that the four steps in this invention—anodic complex breaking, cathode multi-metal synergistic deposition, endogenous Zn thermal volatilization pore formation, and high-temperature solid solution conversion—have a synergistic effect. The absence of any key step will lead to a significant decrease in pore structure, alloy phase, and electrocatalytic degradation performance.

[0048] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing mesoporous high-entropy alloys by recovering multi-metals from electroplating wastewater based on electrodeposition-thermal pore-forming, characterized in that, Specifically, the following steps are included: The first step is to prepare a multi-metal precursor by electrodeposition: a modified titanium-based composite electrode is used as the cathode, a metal-based oxide conductive electrode is used as the anode, and electroplating wastewater containing at least four transition metal ions from Zn and Fe, Co, Ni, Cu, Cr, and Mn is used as the electrolyte. Constant voltage electrodeposition is performed. During the electrodeposition process, an oxidation-complex breaking reaction occurs at the anode, which dissociates the complexed metal ions in the wastewater into free metal ions. Simultaneous synergistic reduction deposition of multi-metal ions occurs at the cathode, and a titanium-based electrode material loaded with multi-metal precursors is obtained on the surface of the titanium-based cathode. The second step is to prepare a mesoporous high-entropy alloy by high-temperature heat treatment: the titanium-based electrode material loaded with the multi-metal precursor is subjected to high-temperature heat treatment in an inert atmosphere. The zinc component in the electroplating wastewater volatilizes and migrates at high temperature, forming a mesoporous structure in situ inside the material. At the same time, the multi-metal component undergoes solid solution transformation to form a mesoporous high-entropy alloy.

2. The method for preparing mesoporous high-entropy alloys based on electrodeposition-thermal pore-forming to recover multi-metals from electroplating wastewater according to claim 1, characterized in that, The relative deviation between the radius of the transition metal ions and zinc ions is ≤15%, and the metal ions contained in the electroplating wastewater are six kinds: Zn, Fe, Co, Ni, Cu and Cr.

3. The method for preparing mesoporous high-entropy alloys based on electrodeposition-thermal pore-forming to recover multi-metals from electroplating wastewater according to claim 1, characterized in that, The modified titanium-based composite electrode is a surface-modified titanium mesh or titanium plate used to regulate the pH and ion transport at the cathode interface; the metal-based oxide conductive electrode is an insoluble inert anode that does not introduce exogenous metal impurities during electrodeposition.

4. The method for preparing mesoporous high-entropy alloys by recovering multi-metals from electroplating wastewater based on electrodeposition-thermal pore-forming according to claim 1, characterized in that, In the first step, the electrodeposition process parameters are: anode-cathode distance 1~3cm, applied voltage 1~10V, and electrodeposition at room temperature for 1~5h.

5. The method for preparing mesoporous high-entropy alloys by recovering multi-metals from electroplating wastewater based on electrodeposition-thermal pore-forming according to claim 4, characterized in that, The distance between the anode and cathode is 2 cm, a voltage of 5V is applied, and electrodeposition is carried out at room temperature for 2 hours.

6. The method for preparing mesoporous high-entropy alloys by recovering multi-metals from electroplating wastewater based on electrodeposition-thermal pore-forming according to claim 1, characterized in that, In the second step, the high-temperature heat treatment process parameters are as follows: under argon protection, the temperature is increased to 900~1200℃ at a heating rate of 2~10℃ / min, held for 1~48h, and then naturally cooled with the furnace.

7. The method for preparing mesoporous high-entropy alloys by recovering multi-metals from electroplating wastewater based on electrodeposition-thermal pore-forming according to claim 6, characterized in that, Heat to 900~950℃ at a heating rate of 5℃ / min, and hold for 6~18 hours.

8. The method for preparing mesoporous high-entropy alloys based on electrodeposition-thermal pore-forming to recover multi-metals from electroplating wastewater according to claim 1, characterized in that, The zinc component is derived solely from the electroplating wastewater itself, requiring no additional pore-forming agent or zinc source. After high-temperature heat treatment, the zinc component is essentially volatilized and removed, with a residual amount of less than 1 wt.%. The mesoporous high-entropy alloy material prepared by this method has a uniformly distributed mesoporous structure and a specific surface area of ​​50–200 m². 2 / g, consisting of a high-entropy solid solution phase formed by five or more metallic elements, and containing no carbon-based support.

9. The application of a mesoporous high-entropy alloy material prepared by the method according to any one of claims 1-8 in the electrocatalytic degradation of organic pollutants, characterized in that, Using the aforementioned mesoporous high-entropy alloy material as the anode and a titanium sheet as the cathode, water containing organic pollutants is electrocatalytically degraded under a constant current electric field.

10. The application according to claim 9, characterized in that: The organic pollutant is selected from one or more of florfenicol, tetracycline, norfloxacin, and sulfamethoxazole; the constant current is 1~10 A, the degradation time is 30~120 min, and the degradation rate can reach more than 98%.

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