Electrochemical device for extracting copper from copper-containing wastewater and extraction method

Abstract

The invention relates to the technical field of heavy metal wastewater treatment, in particular to an electrochemical device and an extraction method for extracting copper from copper-containing wastewater, an anode material of the electrochemical device is one of activated carbon, graphite, lead dioxide, BDD and CumX1-a-bYaZb, a cathode material of the electrochemical device is one of CunX1-c-dYcZd and a carbon-selenium compound, and after a cathode and an anode are connected with a power supply, the copper is extracted from the copper-containing wastewater. The device is used for treating copper-containing wastewater. Wherein 1 < m < = 2, 1 < = n < 2, and m > n; 0 < = a < = 1, 0 < = b < = 1, and 0 < = a + b < = 1; 0 < = c < = 1, 0 < = d < = 1, and 0 < = c + d < = 1; x, Y and Z are selected from one of S, Se and Te. The copper-based chalcogenide is used as an electrode material and forms an electrochemical device with other electrodes, the device is an electro-catalysis coupling deionization system with electrochemical oxidation complex breaking performance, and the selective removal effect on Cu < 2 + > in organic complex copper-containing wastewater, strong acid wastewater and wastewater interfered by high-concentration salt ions and heavy metal ions is good; by means of the device, the complexing breaking effect on an organic complexing pollutant Cu-EDTA can be effectively achieved, and then Cu < 2 + > extraction is completed.

Description

Electrochemical device and extraction method for extracting copper from copper-containing wastewater Technical Field

[0001] The present invention relates to the technical field of heavy metal wastewater treatment, and in particular to an electrochemical device and an extraction method for extracting copper from copper-containing wastewater. Background Art

[0002] Copper resources play an important role in modern industrial technology, covering important fields such as communications, infrastructure, electrical and electronic equipment, and transportation. Therefore, the application status of copper will become more and more significant in the future. The demand has grown rapidly throughout the 20th century, accompanied by the increasing scarcity and shortage of copper resources. At the same time, copper is a common heavy metal pollutant in wastewater generated by industrial processes such as copper mining and smelting, circuit printing, and metal electroplating, and it has the characteristic of high concentration. In typical electroplating wastewater, the concentration of copper can reach 1500mg / L. Etching copper with ammonia solution is a common method in the manufacture of printed circuit boards; it is reported that the concentration of copper in its waste liquid is as high as 150g / L. Copper emission standards are very strict, ranging from 3.0mg / L in India to 0.1mg / L in Italy. When untreated or substandard copper-containing wastewater is discharged into the environment, Cu 2+ It will combine with sediments, be absorbed by animals and plants, and eventually enter the human body through the food chain, accumulating in the human body and posing a potential threat to health.

[0003] The discharge of heavy metal wastewater not only seriously threatens environmental safety and human health, but also causes a huge waste of heavy metal resources, which runs counter to the concept of green development. Effectively removing copper pollution from wastewater while extracting copper, thereby achieving copper resource recovery, is an important method to solve the current heavy metal pollution and copper resource shortage. However, on the one hand, copper-containing wastewater generated from industries such as smelting and electroplating has harsh environmental conditions and is generally highly acidic (sulfuric acid content reaches 5%-10%). The strong corrosiveness and high toxicity of acidic waste liquid make it a hazardous waste, making the efficient recovery of copper a challenge. In addition, some organic chelating agent pollutants discharged by industry, such as ethylenediaminetetraacetic acid, form stable complexes with heavy metals. These chelating agents are difficult to biodegrade, bioaccumulate, are highly toxic, and highly stable, making them difficult to treat through general water treatment methods.

[0004] In order to meet the emission standards, researchers from various countries have developed various treatment processes to remove Cu from industrial wastewater. 2+ , including chemical precipitation, adsorption, membrane separation, electrodialysis and other treatment technologies.

[0005] The conventional method for treating copper and most heavy metals is precipitation, which involves forming insoluble hydroxides or sulfides under alkaline pH conditions. However, this method is cumbersome, requiring a two-step pH adjustment to disrupt copper complexes and relying on ferrous ions to reduce the divalent copper to cuprous to prevent recomplexation.

[0006] The mechanism of adsorption is to utilize the aggregation of water pollutants at the solid-liquid interface with the adsorbent, and adsorb on the surface of the adsorbent through physical or chemical action, thereby achieving the purpose of removing water pollutants. Due to its simple design and low operating cost, adsorption is one of the most commonly used processes for treating copper-containing wastewater. However, Cu 2+ The operating range of concentrations is often limited, hindering rapid metal uptake and frequent regeneration.

[0007] Membrane technology has evolved from microfiltration (MF) and ultrafiltration (UF) to nanofiltration (NF) and reverse osmosis (RO). Improving membrane selectivity for copper ions requires a deeper understanding of the fundamentals of solute transport within porous membrane media. Furthermore, industrial applications of membrane separation face challenges such as high membrane costs, membrane fouling, and complex water environments.

[0008] The classic electrodialysis process is used to treat wastewater from the metal deposition and electroplating industries. This strategy is suitable for non-selective copper removal and recovery. However, the residual wastewater generated during copper ore processing is highly acidic and contains high concentrations of various heavy metals such as iron, zinc, and copper, making it difficult to effectively treat.

[0009] Therefore, there is an urgent need to develop an economical and efficient method for treating copper-containing wastewater to recover copper from the wastewater.

[0010] Summary of the Invention

[0011] In order to solve the above problems, the present invention provides an electrochemical device and extraction method for extracting copper from copper-containing wastewater, which realizes highly selective adsorption and efficient extraction and recovery of copper ions in copper-containing wastewater.

[0012] The first aspect of the present invention provides an electrochemical device for extracting copper from copper-containing wastewater, wherein the anode material of the electrochemical device is activated carbon, graphite, lead dioxide, BDD, Cu m X 1-a-b Y a Z b One of the cathode materials is Cu n X 1-c-d Y c Z d , one of the carbon-selenium complexes, after the anode and cathode are connected to the power supply, it is used to treat copper-containing wastewater; specifically, the cathode material is a cathode active material, and the anode material is an anode active material.

[0013] Among them, 1<m≤2, 1≤n<2, and m>n; 0≤a≤1, 0≤b≤1 and 0≤a+b≤1; 0≤c≤1, 0≤d≤1 and 0≤c+d≤1; X, Y, and Z are selected from one of S, Se, and Te.

[0014] Specifically, the Cu m X 1-a-b Y a Z b 、Cu n X 1-c-d Y c Z d It is a copper-based chalcogenide, which can be listed as follows: CuS, CuSe, CuTe, CuS@CuSe, CuS 0.3 Se 0.7 、CuS 0.5 Se 0.5 、CuS 0.7 Se 0.3 、CuS 0.3 Se 0.7 , Cu2S, Cu2Se, Cu2Te, Cu2S 0.3 Se 0.7 、Cu2S 0.7 Se 0.3 、Cu2Se 0.7 Te 0.3 wait.

[0015] In some embodiments, the anode material of the electrochemical device is one of activated carbon, graphite, lead dioxide, and BDD; the cathode material is one of copper selenide, copper selenide sulfide, and a carbon-selenium complex. The anode and cathode are connected to a power supply and a direct current of 0.6-4.0V is applied, and the device is used to treat organic wastewater containing Cu-EDTA and acidic electroplating wastewater.

[0016] In some preferred embodiments, the electrochemical device uses an activated carbon electrode as the anode and a hydrothermally prepared copper selenide electrode as the cathode. The anode and cathode are connected by wires and powered on to apply a DC voltage of 0.6-4.0V to obtain the electrochemical device, which is then used to treat organic wastewater containing Cu-EDTA and acidic electroplating wastewater. The device system is used to electrochemically oxidize and decomplex Cu-EDTA, and the released Cu(II) ions are selectively adsorbed at the copper selenide cathode.

[0017] In some embodiments, the copper selenide is prepared as follows:

[0018] Selenium powder is stirred and dissolved in hydrazine hydrate to obtain mixture A; ethanol and water are mixed in proportion, anhydrous copper chloride is added and stirred to dissolve, to obtain mixture B; A and B are mixed and stirred to obtain a mixture, and the mixture is placed in an oven, heated to 150-200°C and reacted for 20-30 hours to obtain a crude copper selenide product.

[0019] In some embodiments, the molar ratio of the selenium powder to anhydrous copper chloride is 1:1.

[0020] In some embodiments, the cathode electrode is obtained by the following method:

[0021] Conductive carbon black and copper selenide material are mixed evenly, then added to a solvent and stirred, and after adding a binder, stirring is continued until a uniform mixture is obtained; the obtained mixture is coated on graphite paper, and the coated graphite paper is placed at a certain temperature and dried overnight to finally obtain a cathode electrode with copper selenide as an active material; specifically, the solvent is anhydrous ethanol; and the drying temperature is 60°C.

[0022] The above copper selenide powder is replaced with activated carbon powder, and the same method can be used to prepare the anode electrode used in the system; specifically, the anode electrode is obtained by the following method:

[0023] Conductive carbon black and activated carbon material are mixed evenly, then added to a solvent and stirred, and after adding a binder, stirring is continued until a uniform mixture is obtained; the obtained mixture is coated on graphite paper, and the coated graphite paper is dried at 60°C overnight to finally obtain an electrocatalytic anode electrode with activated carbon as the active material.

[0024] The above electrodes were assembled into a device system to treat acidic wastewater containing Cu-EDTA pollutants. Specifically, the above copper selenide cathode, activated carbon anode, power supply and 50mL copper-containing wastewater were used to construct an electrochemical device. Under a certain voltage, the charged ions in the wastewater were attracted to the electrodes with opposite charges. The pH value was adjusted to acidic conditions by concentrated sulfuric acid, and anodic oxidation and complexation were broken and the cathode selectively adsorbed Cu. 2+ In addition, for Cu in wastewater 2+ The concentration of Cu-EDTA was determined and the components of Cu-EDTA were analyzed to determine the copper extraction effect. The electrochemical oxidation decomposition system with copper selenide electrode as cathode can decompose the Cu released by anode decomposition under strong acidic conditions and complex ion composition. 2+ The selective extraction is performed to achieve the purpose of recovering copper resources. Specifically, the power supply voltage is 0.6-4.0V, and the pH value is 0.1-5.

[0025] In some preferred embodiments, the electrochemical device further comprises an anion exchange membrane.

[0026] A second aspect of the present invention provides a method for extracting copper from copper-containing wastewater, wherein the method uses the electrochemical device described in any one of the above items to extract copper from the copper-containing wastewater by an electrochemical method.

[0027] In some embodiments, the method comprises the following steps:

[0028] (1) Synchronous copper embedding and copper removal process: Using electrodialysis reactor mode, Cu m X 1-a-b Y a Z b The electrode is used as the anode, with Cu n X 1-c-d Y c Z d The electrode serves as the cathode, and the anode and cathode are separated by an anion exchange membrane. A supporting electrolyte salt solution is added to the anode chamber, and copper-containing wastewater to be treated is added to the cathode chamber. After power is turned on, a copper-rich electrode is formed at the cathode, and at the same time, a copper-deficient electrode is formed at the anode. A high-concentration copper-containing solution is obtained in the anode chamber, and copper ions (II) in the copper-containing wastewater in the cathode chamber are selectively adsorbed onto the cathode material.

[0029] (2) Regeneration process: After the reaction in step (1) is completed, the positive and negative poles of the power supply are switched to perform electrode exchange, the solution in the anode chamber after the electrode exchange is replaced with a fresh supporting electrolyte salt solution, and the solution in the cathode chamber after the electrode exchange is replaced with copper-containing wastewater, and the power is turned on again to perform anode copper removal and cathode copper embedding, thereby achieving copper extraction from the copper-containing wastewater and completing the cyclic regeneration of the electrode;

[0030] Among them, 1<m≤2, 1≤n<2, and m>n; 0≤a≤1, 0≤b≤1 and 0≤a+b≤1; 0≤c≤1, 0≤d≤1 and 0≤c+d≤1; X, Y, and Z are selected from one of S, Se, and Te.

[0031] In some preferred embodiments, the method comprises the following steps:

[0032] (1) Synchronous copper embedding and copper removal processes: an electrodialysis reactor mode is adopted, with a Cu2Se electrode as the anode and a CuSe electrode as the cathode, and the anode and cathode are separated by an anion exchange membrane. A supporting electrolyte salt solution is added to the anode chamber, and the copper-containing wastewater to be treated is added to the cathode chamber. After power is turned on, the copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded in the cathode material to form a copper-rich Cu2Se electrode. At the same time, the Cu2Se as the anode active material loses copper (I) ions and becomes a copper-deficient CuSe electrode. A high-concentration copper-containing solution is obtained in the anode chamber, and the copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed onto the cathode material.

[0033] (2) Regeneration process: After the reaction of step (1) is completed, the positive and negative poles of the power supply are reversed to exchange the electrodes. The copper-rich Cu2Se electrode generated in step (1) is used as the anode, and the copper-deficient CuSe electrode generated in step (1) is used as the cathode. The solution in the anode chamber where the copper-rich Cu2Se electrode is located is replaced with a fresh supporting electrolyte salt solution, and the solution in the cathode chamber where the copper-deficient CuSe electrode is located is replaced with copper-containing wastewater. The power is turned on again to remove copper from the anode and embed copper in the cathode, thereby extracting copper from the copper-containing wastewater and completing the cycle regeneration of the electrodes.

[0034] The method comprises the following steps: step (1) constructing a "Cu2Se electrode | supporting electrolyte | anion exchange membrane | copper-containing wastewater | CuSe electrode" system for simultaneous copper extraction and copper removal; step (2) constructing a "CuSe electrode | copper-containing wastewater | anion exchange membrane | supporting electrolyte | Cu2Se electrode" system by switching the positive and negative electrodes of the battery and adjusting the solutions in the anode and cathode chambers to perform electrode regeneration and obtain a copper-rich solution, thereby achieving highly selective extraction and recovery of copper from the copper-containing wastewater, and performing electrode regeneration while treating the wastewater, thereby further improving treatment efficiency and reducing electrode material costs.

[0035] In some embodiments, after completing step (1) or (2), the high-concentration copper-containing solution in the anode chamber is collected and used for electrolytic refining of crude copper after impurities are removed.

[0036] In some embodiments, the concentration of copper (II) ions in the high-concentration copper-containing solution is above 10,000 mg / L, and the impurity removal method is electrolysis. It should be noted that when a copper-based sulfide compound is used as a cathode active material to form a counter electrode, and is assembled with an anion exchange membrane and a power supply to form an electrodialysis reaction device to treat copper-containing wastewater, the concentration of copper (II) ions in the high-concentration copper-containing solution obtained is usually consistent with the concentration of copper (II) ions in the copper-containing wastewater; in order to enrich copper (II) ions when treating wastewater with a low copper content, in addition to using a fresh supporting electrolyte solution for the first time, the subsequent treatment can use the anode chamber solution (i.e., high-concentration copper-containing wastewater) collected in the previous treatment to replace the supporting electrolyte solution until the concentration of copper (II) ions in the high-concentration copper-containing solution reaches a higher enrichment concentration, such as 10,000 mg / L required for electrolytic copper extraction, to complete the enrichment of copper (II) ions. At this time, the concentration of copper (II) ions in the high-concentration copper-containing solution is the cumulative concentration of the treatment process.

[0037] At the same time, the electrochemical device of the present invention is usually connected in series with multiple groups of cathodes and anodes in actual applications and assembled into an integrated device with multiple anion exchange membranes and power supplies. The integrated device includes multiple processing modules, thereby increasing the copper-containing wastewater treatment capacity per unit volume of the device; when the copper (II) ion concentration in the copper-containing wastewater does not reach the copper-containing wastewater discharge requirement after passing through the device or the enriched copper ion concentration does not reach the required concentration, if the cathode adsorbs copper (II) ions and has not yet reached saturation, after one treatment, only fresh copper-containing wastewater is needed to replace the wastewater treated in the cathode chamber, without replacing the anode chamber solution, and continuing the power treatment. Repeating this operation until the cathode reaches adsorption saturation can achieve copper (II) ion enrichment in the anode chamber; if the cathode has been adsorbed saturated, it can be regenerated in the reverse polarity for further treatment. In some embodiments, in steps (1) and (2), the voltage of the power supply is 0.1-1.4V, and the power supply time is 60-180min.

[0038] In some embodiments, in step (1), the Cu2Se electrode is prepared by mixing Cu2Se, a conductive carbon material, and a binder PVDF in a mass ratio of 7-9:2-0.5:1-0.5.

[0039] In some embodiments, in step (1), the CuSe electrode is prepared by mixing CuSe, a conductive carbon material, and a binder PVDF in a mass ratio of 7-9:2-0.5:1-0.5.

[0040] In some embodiments, the conductive carbon material is selected from one or more of acetylene black, carbon nanotubes, graphene, graphite and carbon fiber.

[0041] Specifically, Cu m X 1-a-b Y a Z b Electrode and Cu n X 1-c-d Y c Z d The preparation methods of the electrodes are similar to those of Cu2Se and CuSe, which are respectively m X 1-a-b Y a Z b / Cu n X 1-c-d Y c Z d , conductive carbon material and binder PVDF are mixed in a mass ratio of 7-9:2-0.5:1-0.5.

[0042] In some embodiments, in step (1) and step (2), the supporting electrolyte salt solution is a sulfate solution or a chloride solution, the concentration of sulfate in the sulfate solution is 0.1-2 mol / L, and the concentration of chloride ions in the chloride solution is 0.1-2 mol / L.

[0043] For example, the sulfate solution may include sodium sulfate solution, potassium sulfate solution, magnesium sulfate solution, ammonium sulfate solution, zinc sulfate solution, etc.; the chloride solution may include sodium chloride solution, potassium chloride solution, ammonium chloride solution, etc.

[0044] In some embodiments, step (2) is repeated 10-20 times.

[0045] In some embodiments, the copper-containing wastewater is one of electroplating acidic wastewater, comprehensive discharge wastewater generated by circuit board printing, copper-containing wastewater from copper smelting, and copper-containing wastewater after chelation.

[0046] In some embodiments, the copper (II) ion concentration in the copper-containing wastewater is 0.5-10000 mg / L. The pH value of the copper-containing wastewater is 0.1-5.0. Specifically, when the pH of the copper-containing wastewater is greater than 5.0, sulfuric acid or hydrochloric acid is required to adjust the pH to 0.1-5.0.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) The present invention uses copper-based sulfide compounds as electrode materials and other electrodes such as carbon materials, BDD and other electrodes to form an electrochemical device. The device is an electrocatalytic coupled deionization system with electrochemical oxidation and decomposition performance, and has a good selective removal effect on copper (II) ions in organic complex copper-containing wastewater, strongly acidic wastewater, and wastewater interfered with by high concentrations of salt ions and heavy metal ions; the device can effectively achieve the decomposition of organic complex pollutants Cu-EDTA, degrading it into a lower-order complex form or even completely degrading and releasing copper (II) ions, thereby completing the extraction of copper (II) ions; more importantly, compared with CuS electrodes, CuSe still has a higher electrical adsorption capacity in an acidic environment (1 mol / L hydrochloric acid).

[0049] (2) The present invention further uses copper-based sulfide compounds as the active materials of the cathode and anode to form a counter electrode, which is assembled with an anion exchange membrane and a power supply to form an electrodialysis reaction device. It can simultaneously carry out copper removal and copper embedding reactions at a lower voltage and a wider pH range. Combined with the electrode regeneration step, the copper extraction operation can be carried out continuously, greatly improving the copper extraction efficiency. It has high efficiency and good selectivity for removing copper (II) ions from copper-containing wastewater.

[0050] (3) The copper-based sulfide compound electrode material of the present invention has the advantages of high adsorption capacity and strong selectivity in treating copper-containing electroplating wastewater, and can achieve selective extraction of copper (II) ions under the conditions of interference from high concentrations of salt ions and heavy metal ions and high acidity; the present invention adopts a double copper-based sulfide compound as the two poles of the electrochemical reactor, and utilizes the excellent copper (II) ion extraction performance of the double copper-based sulfide compound electrode pair to achieve a high copper ion adsorption capacity under low voltage conditions; and the electrode pair also shows good selective adsorption ability for copper (II) ions in a high concentration multi-metal ion coexistence system (removal efficiency is greater than 90%); in addition, the double copper-based sulfide compound electrode pair treatment system of the present invention is also suitable for the treatment of copper-containing wastewater in a wide pH range, overcoming the limitation that traditional adsorption materials can only perform copper extraction operations in a narrow pH range; the present invention verifies the feasibility of the double copper-based sulfide compound electrode pair system in effectively extracting copper ions in the treatment of actual wastewater, and can be applied to the selective extraction of copper (II) ions in strongly acidic copper-containing wastewater with complex components, opening up new avenues for wastewater extraction and recovery of copper resources.

[0051] (4) The excellent removal performance of the double copper-based sulfide compound electrode pair of the present invention for copper (II) ions is derived from the reversible conversion between different copper-based sulfide compound electrodes in the double copper-based copper compound electrode pair. By switching the positive and negative poles of the power supply and adjusting the solutions in the anode and cathode chambers, the electrodes are reversibly converted, i.e., electrode regeneration is performed. The electrode regeneration is carried out simultaneously with the copper extraction process, thereby realizing continuous treatment of copper-containing wastewater, greatly improving the copper extraction efficiency and extending the service life of the electrodes, thereby reducing the treatment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0053] FIG1 is an X-ray diffraction spectrum of the copper selenide electrode material prepared in Example 1;

[0054] FIG2 is a scanning electron microscope image of the copper selenide electrode material prepared in Example 1;

[0055] FIG3 is a schematic diagram of the combined device of Example 3;

[0056] FIG4 is a curve showing the change of Cu-EDTA concentration over time in Example 3 when treating Cu-EDTA-containing wastewater;

[0057] FIG5 is a diagram showing the adsorption of copper and other ions by the copper selenide cathode electrode when treating acidic electroplating wastewater in Example 4;

[0058] FIG6 is a diagram showing the adsorption of copper and other heavy metals by a copper selenide cathode electrode when treating wastewater of a complex system containing multiple heavy metal components according to Example 5;

[0059] Figure 7 is a schematic diagram of the structure of the electrochemical device constructed in Example 6, wherein 1-Cu2Se anode, 2-CuSe cathode, 3-anion exchange membrane, 4-DC power supply, 5-supporting electrolyte, 6-copper-containing wastewater;

[0060] FIG8 is a schematic diagram of the structure of the electrochemical device for the regeneration process of Example 6, wherein: 11-Cu2Se anode (obtained by copper embedding CuSe), 21-CuSe cathode (obtained by copper removal from Cu2Se), 3-anion exchange membrane, 4-DC power supply, 5-supporting electrolyte, and 6-copper-containing wastewater;

[0061] FIG9 is a diagram showing the adsorption of copper and other ions in Example 6 when treating copper mine water. DETAILED DESCRIPTION

[0062] The following will clearly and completely describe the technical solutions of the present invention in conjunction with specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0063] Example 1

[0064] Dissolve 0.316g of selenium powder in 10mL of hydrazine hydrate and stir vigorously at 70°C to form Mixture A. Dissolve 0.523g of anhydrous copper chloride in an ethanol-water mixture (the volume ratio of ethanol to water is 3:2) and stir to form Mixture B. Add Mixture A dropwise to Mixture B and stir at room temperature for 30 minutes. The reactants are then transferred to a reactor, placed in an oven at 180°C, and reacted for 24 hours. After cooling to room temperature, the solid product is washed multiple times with anhydrous ethanol and deionized water. Finally, dry it in an oven at 60°C overnight to obtain the copper selenide electrode material.

[0065] The X-ray diffraction spectrum of the copper selenide electrode material prepared in Example 1 is shown in Figure 1. The sample's primary diffraction peaks fully match the characteristic peaks corresponding to hexagonal copper selenide (CuSePDF#34-0171). No other impurity peaks are observed, demonstrating the successful preparation of the copper selenide material and the high purity of the sample.

[0066] Figure 2 is a scanning electron microscope image of the prepared copper selenide material. As can be seen from the image, the copper selenide nanomaterial exhibits an irregular hexagonal nanosheet shape, with a size ranging from approximately 200nm to 500nm, and is relatively dispersed without stacking.

[0067] Example 2

[0068] The copper selenide electrode material prepared in Example 1 was used as the active material and mixed uniformly with conductive carbon black in a mass ratio of 8:1. Anhydrous ethanol was added and stirred uniformly. A binder was then added with an active material to binder ratio of 8:1 and stirred uniformly. The resulting mixture was then coated onto graphite paper to a film thickness of 100-600 μm. The coated graphite paper was dried overnight at 60°C to obtain a deionization cathode electrode with copper selenide as the active material.

[0069] An activated carbon anode electrode was prepared using the same method: activated carbon was mixed with conductive carbon black at a mass ratio of 8:1. Anhydrous ethanol was added and stirred thoroughly. A binder was then added at a ratio of 8:1 and stirred thoroughly. The resulting mixture was then coated onto graphite paper to a film thickness of 100-600 μm. The coated graphite paper was dried overnight at 60°C to obtain an electrocatalytic anode electrode with activated carbon as the active material.

[0070] Example 3

[0071] The electrochemical oxidation decomposition and cathode selective copper extraction combined device constructed by the copper selenide cathode electrode and activated carbon anode electrode obtained in Example 2 was used to treat wastewater containing Cu-EDTA pollutants and acidic electroplating wastewater, that is, to extract copper. The specific method is as follows:

[0072] A copper selenide cathode electrode, an activated carbon anode electrode, a power supply, and 50 mL of copper-containing waste liquid were used to construct a unified system. At 1 V, the charged ions in the waste liquid were attracted to the electrodes with opposite charges. The pH value was adjusted to 1 by concentrated sulfuric acid, and the anodic oxidation and complexation were broken and the cathode selectively adsorbed Cu. 2+ Reaction, the schematic diagram of the device is shown in Figure 3. In addition, for Cu in the wastewater 2+The concentration of Cu-EDTA was measured and the components of Cu-EDTA were analyzed. As shown in Figure 4, after 300 minutes of electrochemical treatment, the concentration of Cu-EDTA in the waste liquid was significantly reduced by HPLC, from the initial 400 mg / L to 0.2 mg / L, indicating that the capacitive deionization system has a good removal effect on Cu-EDTA in the waste liquid. Under normal conditions, Cu-EDTA exists in the wastewater in a negatively charged form. Under the action of voltage, Cu-EDTA is attracted to the activated carbon anode. Due to the anodic oxidation of the activated carbon anode, the generated hydroxyl free radicals and other substances destroy the Cu-EDTA. 2+ The complex structure with -EDTA- generates lower-order copper complex species or directly releases Cu 2+ , achieving the breaking of the Cu-EDTA complex. The released Cu 2+ Under the action of voltage, it is attracted by the cathode and finally recovered by the copper selenide electrode.

[0073] Example 4

[0074] Copper selenide electrodes selectively extract copper from actual acidic electroplating wastewater. The specific method is:

[0075] The electroplating wastewater was taken from an electroplating material company, and the pH value was adjusted to a strong acidity, at which point the pH was 1. The wastewater was treated by a combined device of electrochemical oxidation and cathode selective copper extraction. The specific experiment was carried out in the same way as in Example 3. As shown in Figure 5, after adsorption, Cu 2+ The concentration dropped from 417.12 mg / L to 1.92 mg / L under the conditions of other ion interference (Na + :553.97mg / L,Ca 2+ :672.91mg / L), for Cu 2+ The removal rate of Na + and Ca 2+ The removal rates of Cu and Se were only 3.21% and 1.95% respectively. The results show that even under the actual conditions of strong acidity and high concentration of interfering ions, the removal rate of Cu and Se was only 3.21% and 1.95% respectively. 2+ It can still show excellent adsorption performance and selectivity.

[0076] Example 5

[0077] Copper selenide electrodes selectively extract copper in the presence of heavy metal interference. The specific method is:

[0078] The copper selenide electrode was used to electro-adsorb a mixed solution system of copper concentration (10 mg / L): other heavy metal concentrations at a ratio of 1:10. The specific experiments were carried out in the same way as in Example 3. As shown in Figure 6, the results show that even under the condition of a concentration ratio of 1:10, the copper selenide electrode can electro-adsorb Cu. 2+The removal rate of ions is still 99.02%, while the removal rates of other ions are lower. The removal rate calculation formula is as follows:

[0079] RE: removal efficiency; C0: initial concentration; C t : Equilibrium concentration.

[0080] Example 1 uses a hydrothermal method to prepare a copper selenide material with a relatively high purity. Example 2 uses the copper selenide material prepared in Example 1 to prepare a copper selenide electrode as a cathode, and uses activated carbon to prepare an activated carbon electrode as an anode. Examples 3-5 use the anode and cathode prepared in Example 2 to construct an electrochemical assembly "activated carbon electrode | copper-containing wastewater | CuSe electrode" for treating copper-containing wastewater, wherein Example 3 is used to treat wastewater containing Cu-EDTA. The results show that the electrochemical device system of the present invention has electrochemical oxidation decomposition performance, which can effectively achieve decomposition of the organic complex pollutant Cu-EDTA, degrading it to a lower-order complex form or even completely degrading and releasing Cu 2+ At the same time, the electrochemical system of the present invention can also release Cu 2+ Adsorption is carried out to achieve Cu 2+ Extraction and recovery; Example 4 was used to treat acidic electroplating wastewater. The results showed that the electrochemical device system of the present invention was effective in the presence of strong acidity and high concentrations of interfering ions for Cu 2+ Still has excellent adsorption performance and selectivity; Example 5 is used to treat copper-containing wastewater containing multiple heavy metals. The results show that the electrochemical device system of the present invention has excellent adsorption performance and selectivity for Cu under heavy metal interference. 2+ Still has good removal rate and selectivity.

[0081] Example 6

[0082] (1) Synchronous copper embedding and copper removal processes: an electrochemical device was constructed, and the schematic diagram of the device structure is shown in FIG7 . An electrodialysis reactor mode was adopted, with a Cu2Se electrode as the anode and a CuSe electrode as the cathode. The anode and the cathode were separated by an anion exchange membrane. 100 mL of a supporting electrolyte solution, sodium sulfate solution (the concentration of sulfate ions was 0.5 mol / L) was added to the anode chamber, and 100 mL of copper-containing wastewater to be treated (the concentration of copper (II) ions was 200 mg / L) was added to the cathode chamber. The power supply was turned on and a 1 V DC voltage was applied. The copper (II) ions in the copper-containing wastewater in the cathode chamber were embedded in the cathode material to form a copper-rich Cu2Se electrode. The reaction that occurred was: CuSe+2e - +Cu 2+ =Cu2Se. At the same time, the Cu2Se as the anode loses copper (I) ions and becomes a copper-deficient CuSe electrode. The reaction that occurs is: Cu2Se–2e - =CuSe+Cu2+ ; After 60 minutes of power-on, a high-concentration copper-containing solution of 199.36 mg / L was obtained in the anode chamber, and the copper (II) ions in the copper-containing wastewater entering the cathode chamber will be selectively adsorbed onto the cathode material, and the copper ion concentration of the treated copper-containing wastewater is 0.89 mg / L.

[0083] (2) Regeneration process: After the reaction is completed, the positive and negative poles of the power supply are reversed to exchange the electrodes. The copper-rich Cu2Se electrode generated in step (1) is used as the anode, and the copper-deficient CuSe electrode generated in step (1) is used as the cathode. The solution in the anode chamber where the copper-rich Cu2Se electrode is located is replaced with 100 mL of fresh supporting electrolyte salt solution sodium sulfate solution (the concentration of sulfate ions is 0.5 mol / L), and the solution in the cathode chamber where the copper-deficient CuSe electrode is located is replaced with 100 mL of copper-containing wastewater (the concentration of copper (II) ions is 200 mg / L). As shown in Figure 8, the structural schematic diagram of the electrochemical device during the regeneration process is shown. The process of step (1) is repeated by powering on again. The power-on voltage is 1 V and the power-on time is 60 min. The anode is stripped of copper and the cathode is embedded with copper. A high-concentration copper-containing solution of 198.44 mg / L is obtained in the anode chamber. The copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed onto the cathode material, thereby realizing the extraction of copper from the copper-containing wastewater and completing the cyclic regeneration of the electrode.

[0084] In step (1), the Cu2Se electrode is prepared by mixing Cu2Se, acetylene black, and binder PVDF in a mass ratio of 7:0.5:1, and the CuSe electrode is prepared by mixing CuSe, acetylene black, and binder PVDF in a mass ratio of 7:0.5:1. The specific preparation method is the same as that in Example 2.

[0085] The copper-containing wastewater comes from a copper mine pit water with a pH of 2. Its chemical composition is shown in Table 1. The adsorption of copper and other ions in the copper mine pit water by the electrochemical device and method of the present invention is shown in Figure 9.

[0086] Table 1 Chemical composition of Tongkeng water (unit: mg / L)

[0087] As can be seen from Figure 9, Example 6 uses the "CuSe|Cu2Se" electrode pair to construct an electrochemical device to treat copper pit water from a copper mine, and can simultaneously realize the copper embedding and copper removal processes. At the same time, by switching the positive and negative poles of the power supply and adjusting the solutions in the anode and cathode chambers, the electrode regeneration and copper extraction processes are carried out simultaneously, which greatly improves the treatment efficiency of copper-containing wastewater and the service life of the electrodes and reduces costs. In Example 6, the removal rate of copper (II) ions in step (1) reached 99.55%, and the ion removal rates of Fe, Ca, Mg, and Pb were all less than 5%, indicating that the present device system has good selectivity for copper (II) ions; in the electrode regeneration process of the secondary treatment of step (2), the anode chamber obtained a high-concentration copper-containing solution of 198.44 mg / L, and the desorption rate reached 99.22%, with a good desorption effect; step (2) was repeated 15 times, that is, the 17th treatment was performed. After the electrode was regenerated 16 times, the copper (II) ion concentration of the copper-containing wastewater in the cathode chamber was reduced from 200 mg / L to 12 mg / L, and the removal rate of copper (II) ions was 94%, which still achieved efficient extraction of copper ions from copper-containing wastewater. At the same time, after the electrode was regenerated 16 times, the anode chamber still obtained a high-concentration copper-containing solution of 186 mg / L, and the desorption rate reached 93%, indicating a good electrode cyclic regeneration effect. The desorption rate calculation formula is as follows:

[0088] DE: desorption efficiency; C0: initial concentration; C t : concentration after desorption.

[0089] Example 7

[0090] The difference between this embodiment and embodiment 6 is that an integrated device is used to treat copper-containing wastewater, and the corresponding operations are different. The specific operating steps are as follows:

[0091] (1) Synchronous copper embedding and copper removal processes: Build an electrochemical device, connect multiple groups of cathodes and anodes in series and assemble them into an integrated device with multiple anion exchange membranes and power supplies. The integrated device includes multiple processing modules, adopts an electrodialysis reactor mode, uses a Cu2Se electrode as an anode, and a CuSe electrode as a cathode. The anode and cathode are separated by an anion exchange membrane. 100 mL of sodium sulfate solution (the concentration of sulfate ions is 0.5 mol / L) is added to the anode chamber, and 100 mL of copper-containing wastewater to be treated (the concentration of copper (II) ions is 200 mg / L) is added to the cathode chamber; turn on the power supply and apply a 1 V DC voltage. The copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded in the cathode material to form a copper-rich Cu2Se electrode. The reaction that occurs is: CuSe+2e - +Cu 2+ =Cu2Se. At the same time, the Cu2Se as the anode loses copper (I) ions and becomes a copper-deficient CuSe electrode. The reaction that occurs is: Cu2Se–2e - =CuSe+Cu2+ After 60 minutes of power application, a high-concentration copper solution of 199.36 mg / L was obtained in the anode chamber. The copper (II) ions in the copper-containing wastewater entering the cathode chamber were selectively adsorbed onto the cathode material, and the copper ion concentration of the treated copper-containing wastewater was 0.89 mg / L.

[0092] (2) The first enrichment process: fresh copper-containing wastewater is used to replace the wastewater treated in the cathode chamber, and step (1) is repeated 50 times to enrich copper (II) ions. After enrichment, a high-concentration copper-containing solution of 10100 mg / L is obtained in the anode chamber.

[0093] (3) Regeneration process: the positive and negative poles of the power supply are switched to exchange the electrodes, the copper-rich Cu2Se electrode generated in step (2) is used as the anode, the copper-poor CuSe electrode generated in step (2) is used as the cathode, the solution in the anode chamber where the copper-rich Cu2Se electrode is located is replaced with 100mL of fresh supporting electrolyte salt solution sodium sulfate solution (the concentration of sulfate ions is 0.5mol / L), and the solution in the cathode chamber where the copper-poor CuSe electrode is located is replaced with 100mL of copper-containing wastewater (the concentration of copper (II) ions is 200mg / L); the power is turned on again and the process of step (1) is repeated, with the power-on voltage of 1V and the power-on time of 60min, to carry out anode copper removal and cathode copper embedding, and a high-concentration copper-containing solution is obtained in the anode chamber. The copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed on the cathode material, thereby realizing the extraction of copper from the copper-containing wastewater and completing the cycle regeneration of the electrode.

[0094] (4) Second enrichment process: fresh copper-containing wastewater is used to replace the wastewater treated in the cathode chamber, and step (3) is repeated 50 times to enrich copper (II) ions. After enrichment, a high-concentration copper-containing solution of 10,000 mg / L is obtained in the anode chamber.

[0095] (5) After completing step (2) or (4), the high-concentration copper-containing solution in the enriched anode chamber is collected and used for electrolytic refining of crude copper after impurities are removed to obtain high-purity electrolytic copper with a purity of more than 99%.

[0096] Example 7 further integrates multiple treatment units, so that copper can be enriched even when the copper (II) ion concentration in the copper-containing wastewater is low, thereby further applying the extracted copper to the electrolytic refining of crude copper, realizing a full range of copper treatment from copper-containing wastewater treatment to waste copper extraction and application, which has high application value and is worthy of industrial promotion.

[0097] Example 8

[0098] (1) Synchronous copper embedding and copper removal processes: Build an electrochemical device, adopt an electrodialysis reactor mode, use a Cu2S electrode as the anode, and a CuS electrode as the cathode. Use an anion exchange membrane to separate the anode and cathode. Add 100 mL of potassium sulfate solution (the concentration of sulfate ions is 1.0 mol / L) as the supporting electrolyte solution to the anode chamber, and add 100 mL of copper-containing wastewater to be treated (the concentration of copper (II) ions is 1000 mg / L) to the cathode chamber; turn on the power supply and apply a 0.1 V DC voltage. The copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded in the cathode material to form a copper-rich Cu2S electrode. The reaction that occurs is: CuS+2e - +Cu 2+ =Cu2S. At the same time, the Cu2S as the anode loses copper (I) ions and becomes a copper-deficient CuS electrode. The reaction that occurs is: Cu2S–2e - =CuS+Cu 2+ After 180 minutes of power-on, a high-concentration copper-containing solution of 996 mg / L was obtained in the anode chamber, and the copper (II) ions in the copper-containing wastewater entering the cathode chamber will be selectively adsorbed onto the cathode material, and the copper ion concentration of the treated copper-containing wastewater is 9.8 mg / L.

[0099] (2) Regeneration process: After the reaction is completed, the positive and negative poles of the power supply are reversed to exchange the electrodes. The copper-rich Cu2S electrode generated in step (1) is used as the anode, and the copper-poor CuS electrode generated in step (1) is used as the cathode. The solution in the anode chamber where the copper-rich Cu2S electrode is located is replaced with 100 mL of fresh supporting electrolyte salt solution potassium sulfate solution (the concentration of sulfate ions is 1.0 mol / L), and the solution in the cathode chamber where the copper-poor CuS electrode is located is replaced with 100 mL of copper-containing wastewater (the concentration of copper (II) ions is 1000 mg / L); the power is turned on again and the process of step (1) is repeated. The power-on voltage is 0.1 V and the power-on time is 180 min. The anode is decoppered and the cathode is embedded with copper. A high-concentration copper-containing solution of 978 mg / L is obtained in the anode chamber. The copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed onto the cathode material, thereby realizing the extraction of copper from the copper-containing wastewater and completing the cycle regeneration of the electrode.

[0100] In step (1), the Cu2S electrode is made by mixing Cu2S, carbon nanotubes, and binder PVDF in a mass ratio of 8:1:1, and the CuS electrode is made by mixing CuS, carbon nanotubes, and binder PVDF in a mass ratio of 8:1:1. The specific preparation method is the same as that in Example 2.

[0101] The copper-containing wastewater is derived from copper-containing comprehensive wastewater from a PCB circuit board production process with a pH of 4, and its chemical composition is shown in Table 2.

[0102] Table 2 Chemical composition of copper-containing comprehensive wastewater (unit: mg / L)

[0103] Example 8 uses a "CuS|Cu2S" electrode pair to construct an electrochemical device to treat copper-containing comprehensive wastewater from the PCB circuit board production process. It can simultaneously achieve copper embedding and copper removal processes. At the same time, by switching the positive and negative poles of the power supply and adjusting the solutions in the anode and cathode chambers, the electrode regeneration and copper extraction processes are carried out simultaneously, greatly improving the treatment efficiency of copper-containing wastewater. In Example 8, the removal rate of copper (II) ions in step (1) reaches 99.02%, and the desorption rate of the electrode regeneration process in the secondary treatment of step (2) reaches 97.8%, and the electrode recycling effect is good. Repeat step (2) 15 times, that is, the 17th treatment is performed. After the electrode is regenerated 16 times, the copper (II) ion concentration of the copper-containing wastewater in the cathode chamber is reduced from 1000 mg / L to 30 mg / L, and the copper (II) ion removal rate is 97%. It is still possible to achieve efficient extraction of copper ions from copper-containing wastewater. At the same time, after 16 electrode regenerations, the anode chamber still obtains a high-concentration copper-containing solution of 950 mg / L, and the desorption rate reaches 95%, and the electrode recycling effect is good.

[0104] Example 9

[0105] (1) Simultaneous copper embedding and copper removal: Build an electrochemical device and adopt the electrodialysis reactor mode to use Cu2S 0.3 Se 0.7 The electrode is used as the anode, with CuS 0.3 Se 0.7 The electrode is used as a cathode, and the anode and cathode are separated by an anion exchange membrane. 100 mL of a supporting electrolyte solution, sodium chloride solution (chloride ion concentration is 2.0 mol / L) is added to the anode chamber, and 100 mL of copper-containing wastewater to be treated (copper (II) ion concentration is 1000 mg / L) is added to the cathode chamber. The power supply is turned on and a 1.4 V DC voltage is applied. The copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded in the cathode material to form copper-rich Cu2S 0.3 Se 0.7 The reaction at the electrode is: CuS 0.3 Se 0.7 +2e - +Cu 2+ =Cu2S 0.3 Se 0.7 At the same time, Cu2S as the anode 0.3 Se 0.7 Loss of copper (I) ions to become copper-deficient CuS 0.3 Se 0.7 The reaction at the electrode is: Cu2S 0.3 Se 0.7 –2e - =CuS 0.3 Se 0.7 +Cu2+ After 120 minutes of power-on, a high-concentration copper-containing solution of 988 mg / L was obtained in the anode chamber, and the copper (II) ions in the copper-containing wastewater passed into the cathode chamber will be selectively adsorbed onto the cathode material, and the copper ion concentration of the treated copper-containing wastewater is 6.3 mg / L.

[0106] (2) Regeneration process: After the reaction is completed, the positive and negative poles of the power supply are switched to exchange the electrodes, and the copper-rich Cu2S generated in step (1) is used. 0.3 Se 0.7 The electrode is an anode, and the copper-deficient CuS generated in step (1) 0.3 Se 0.7 The electrode is the cathode, and the copper-rich Cu2S 0.3 Se 0.7 The solution in the anode chamber where the electrode is located is replaced with 100 mL of fresh supporting electrolyte salt solution sodium chloride solution (chloride ion concentration is 2.0 mol / L), and the copper-deficient CuS 0.3 Se 0.7 The solution in the cathode chamber where the electrode is located is replaced with 100 mL of copper-containing wastewater (the concentration of copper (II) ions is 1000 mg / L); the power is turned on again and the process of step (1) is repeated, with the power-on voltage being 1.4 V and the power-on time being 120 min, to perform anode copper stripping and cathode copper embedding, and a 966 mg / L high-concentration copper-containing solution is obtained in the anode chamber. The copper (II) ions in the copper-containing wastewater passed into the cathode chamber will be selectively adsorbed onto the cathode material, thereby realizing the extraction of copper from the copper-containing wastewater and completing the recycling regeneration of the electrode at the same time.

[0107] In step (1), Cu2S 0.3 Se 0.7 The electrode is made of Cu2S 0.3 Se 0.7 , graphite, binder PVDF are mixed in a mass ratio of 9:2:1, CuS 0.3 Se 0.7 The electrode is made of CuS 0.3 Se 0.7 , graphite, and binder PVDF are mixed in a mass ratio of 9:2:1. The specific preparation method is the same as that in Example 2.

[0108] The copper-containing wastewater has the same source and composition as the copper-containing wastewater in Example 8.

[0109] Example 9: "CuS 0.3 Se 0.7 |Cu2S 0.3 Se 0.7The electrode pairs are used to construct an electrochemical device to treat copper-containing comprehensive wastewater from the PCB circuit board production process. The copper embedding and copper removal processes can be realized simultaneously. At the same time, by switching the positive and negative poles of the power supply and adjusting the solutions in the anode and cathode chambers, the electrode regeneration and copper extraction processes are carried out simultaneously, which greatly improves the treatment efficiency of the copper-containing wastewater. In Example 9, the removal rate of copper (II) ions in step (1) reaches 99.17%, and the desorption rate of the electrode regeneration process in the secondary treatment of step (2) reaches 96.6%, and the electrode recycling effect is good. Step (2) is repeated 15 times, that is, the 17th treatment is performed. After the electrode is regenerated 16 times, the copper (II) ion concentration of the copper-containing wastewater in the cathode chamber is reduced from 1000 mg / L to 46 mg / L, and the copper (II) ion removal rate is 95.4%. It is still possible to achieve efficient extraction of copper ions from the copper-containing wastewater. At the same time, after the electrode is regenerated 16 times, the anode chamber still obtains a high-concentration copper-containing solution of 948 mg / L, and the desorption rate reaches 94.8%, and the electrode recycling effect is good.

[0110] Example 10

[0111] (1) Synchronous copper embedding and copper removal processes: Build an electrochemical device, connect multiple groups of cathodes and anodes in series and assemble them into an integrated device with multiple anion exchange membranes and power supplies. The integrated device includes multiple processing modules, adopts an electrodialysis reactor mode, uses Cu2S@Cu2Se electrode as anode, uses CuS@CuSe electrode as cathode, separates the anode and cathode with an anion exchange membrane, adds 100mL of supporting electrolyte solution sodium chloride solution (chloride ion concentration is 2.0mol / L) to the anode chamber, and adds 100mL of copper-containing wastewater to be treated (copper (II) ion concentration is 10mg / L) to the cathode chamber; connect the power supply and apply 1V DC voltage, the copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded in the cathode material to form a copper-rich Cu2S@Cu2Se electrode, and the reaction that occurs is: CuS@CuSe+4e - +2Cu 2+ =Cu2S@Cu2Se. At the same time, the Cu2S@Cu2Se as the anode loses copper (I) ions and becomes a copper-deficient CuS@CuSe electrode. The reaction is: Cu2S@Cu2Se–4e - =CuS@CuSe+2Cu 2+ ; Continuously replace the treated wastewater in the cathode chamber with fresh copper-containing wastewater to enrich copper (II) ions. After enrichment, the anode chamber obtains a 10,000 mg / L high-concentration copper-containing solution. The copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed onto the cathode material, and the copper ion concentration of the treated copper-containing wastewater is 0.05 mg / L.

[0112] (2) Regeneration process: After the reaction is completed, the positive and negative poles of the power supply are switched to perform electrode exchange. The copper-rich Cu2S@Cu2Se electrode generated in step (1) is used as the anode, and the copper-deficient CuS@Cu2Se electrode generated in step (1) is used as the cathode. The solution in the anode chamber where the copper-rich Cu2S@Cu2Se electrode is located is replaced with 100 mL of fresh supporting electrolyte salt solution sodium chloride solution (chloride ion concentration is 2.0 mol / L), and the solution in the cathode chamber where the copper-deficient CuS@CuSe electrode is located is replaced with 1 00mL copper-containing wastewater (the concentration of copper (II) ions is 10mg / L); the process of step (1) is repeated after power is applied again, with the power supply voltage being 1V, and copper removal at the anode and copper embedding at the cathode are performed, and the wastewater treated in the cathode chamber is continuously replaced with fresh copper-containing wastewater to enrich the copper (II) ions. After enrichment, a 10000mg / L high-concentration copper-containing solution is obtained in the anode chamber, and the copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed onto the cathode material, thereby realizing the extraction of copper from the copper-containing wastewater and completing the recycling of the electrode.

[0113] (3) After completing step (1) or (2), the high-concentration copper-containing solution in the enriched anode chamber is collected and used for electrolytic refining of crude copper after impurities are removed to obtain high-purity electrolytic copper with a purity of more than 99%.

[0114] In step (1), the CuS@CuSe electrode is prepared by mixing CuS@CuSe, graphite, and binder PVDF in a mass ratio of 9:2:1, and the Cu2S@Cu2Se electrode is prepared by mixing Cu2S@Cu2Se, graphite, and binder PVDF in a mass ratio of 9:2:1. The specific preparation method is the same as that in Example 2.

[0115] The pH value of the copper-containing wastewater is 5.

[0116] Example 10: An electrochemical device constructed with a "CuS@CuSe|Cu2S@Cu2Se" electrode pair was used to treat copper-containing wastewater, enabling simultaneous copper embedding and copper removal. By switching the positive and negative poles of the power supply and adjusting the solutions in the anode and cathode chambers, electrode regeneration and copper extraction were performed simultaneously, significantly improving the treatment efficiency of copper-containing wastewater. In Example 10, the removal rate of copper (II) ions reached 99.5%, and the desorption rate during the electrode regeneration process before secondary treatment and enrichment in step (2) reached 99.1%, demonstrating good electrode regeneration results. Repeat step (2) 15 times, that is, perform the 17th treatment. After the electrode is regenerated 16 times, the copper (II) ion concentration of the copper-containing wastewater in the cathode chamber is reduced from 10 mg / L to 0.24 mg / L, and the removal rate of copper (II) ions is 97.6%. It is still possible to achieve efficient extraction of copper ions from the copper-containing wastewater. At the same time, after the electrode is regenerated 16 times, a high-concentration copper-containing solution of 9.65 mg / L is still obtained in the anode chamber before enrichment, and the desorption rate reaches 96.5%. The electrode cycle regeneration effect is good.

[0117] Example 11

[0118] (1) Synchronous copper embedding and copper removal processes: Build an electrochemical device, connect multiple groups of cathodes and anodes in series and assemble them into an integrated device with multiple anion exchange membranes and power supplies. The integrated device includes multiple processing modules, adopts an electrodialysis reactor mode, uses a Cu2Te electrode as an anode, and a CuTe electrode as a cathode. The anode and cathode are separated by an anion exchange membrane. 100 mL of a supporting electrolyte solution, sodium chloride solution (the concentration of chloride ions is 2.0 mol / L) is added to the anode chamber, and 100 mL of copper-containing wastewater to be treated (the concentration of copper (II) ions is 10 mg / L) is added to the cathode chamber; the power supply is turned on and a 1 V DC voltage is applied. The copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded in the cathode material to form a copper-rich Cu2Te electrode. The reaction that occurs is: CuTe+2e - +Cu 2+ =Cu2Te, and at the same time, the Cu2Te as the anode loses copper (I) ions and becomes a copper-deficient CuTe electrode. The reaction that occurs is: Cu2Te–2e - =CuTe+Cu 2+ ; Continuously replace the treated wastewater in the cathode chamber with fresh copper-containing wastewater to enrich copper (II) ions. After enrichment, the anode chamber obtains a 10,000 mg / L high-concentration copper-containing solution. The copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed onto the cathode material, and the copper ion concentration of the treated copper-containing wastewater is 0.1 mg / L.

[0119] (2) Regeneration process: After the reaction is completed, the positive and negative poles of the power supply are reversed to exchange the electrodes. The copper-rich Cu2Te electrode generated in step (1) is used as the anode, and the copper-deficient CuTe electrode generated in step (1) is used as the cathode. The solution in the anode chamber where the copper-rich Cu2Te electrode is located is replaced with 100mL of fresh supporting electrolyte salt solution sodium chloride solution (the concentration of chloride ions is 2.0mol / L), and the solution in the cathode chamber where the copper-deficient CuTe electrode is located is replaced with 100mL of copper-containing wastewater (the concentration of copper (II) ions is 10mg / L); the power is turned on again and the process of step (1) is repeated, with the power-on voltage being 1V, to carry out anode copper removal and cathode copper embedding, and the wastewater treated in the cathode chamber is continuously replaced with fresh copper-containing wastewater to enrich copper (II) ions. After enrichment, a high-concentration copper-containing solution of 10,000mg / L is obtained in the anode chamber. The copper (II) ions in the copper-containing wastewater introduced into the cathode chamber will be selectively adsorbed on the cathode material, thereby realizing the extraction of copper from the copper-containing wastewater and completing the cycle regeneration of the electrode. (3) After completing step (1) or (2), the high-concentration copper-containing solution in the enriched anode chamber is collected and used for electrolytic refining of crude copper after impurities are removed to obtain high-purity electrolytic copper with a purity of more than 99%.

[0120] In step (1), the CuTe electrode is made by mixing CuTe, graphite, and binder PVDF in a mass ratio of 9:2:1, and the Cu2Te electrode is made by mixing Cu2Te, graphite, and binder PVDF in a mass ratio of 9:2:1. The specific preparation method is the same as that in Example 2.

[0121] The pH value of the copper-containing wastewater is 5.

[0122] Example 11: An electrochemical device is constructed with a "CuTe|Cu2Te" electrode pair to treat copper-containing wastewater. It can simultaneously realize the copper embedding and copper removal processes. At the same time, by switching the positive and negative poles of the power supply and adjusting the solutions in the anode and cathode chambers, the electrode regeneration and copper extraction processes are carried out simultaneously, greatly improving the treatment efficiency of copper-containing wastewater. In Example 11, the removal rate of copper (II) ions reaches 99%, and the desorption rate of the electrode regeneration process in the secondary treatment of step (2) reaches 96.2%, and the electrode recycling effect is good. Repeat step (2) 15 times, that is, the 17th treatment is performed. After the electrode is regenerated 16 times, the copper (II) ion concentration of the copper-containing wastewater in the cathode chamber is reduced from 10 mg / L to 0.62 mg / L, and the copper (II) ion removal rate is 93.8%. It is still possible to achieve efficient extraction of copper ions from copper-containing wastewater. At the same time, after 16 electrode regenerations, the anode chamber before enrichment still obtains a high-concentration copper-containing solution of 9.26 mg / L, and the desorption rate reaches 92.6%, and the electrode recycling effect is good.

[0123] In Examples 6-11, a copper-based sulfide compound is used to form a counter electrode, which is assembled with an anion exchange membrane and a power supply to form an electrodialysis reaction device. The active materials of the cathode and anode of the reaction device are both copper-based sulfide compounds, thereby simultaneously performing anode copper removal and cathode copper embedding, thereby improving the processing speed; and by switching the positive and negative poles of the power supply and adjusting the solutions in the cathode and anode chambers, the electrode regeneration and copper extraction processes are synchronized, thereby achieving continuous treatment of copper-containing wastewater and greatly improving the copper extraction efficiency; at the same time, the electrode regeneration operation greatly extends the service life of the electrode and reduces costs. The electrodialysis reaction device and method of Examples 6-11 can be used to treat actual wastewater, with a high removal rate and selectivity for copper (II) ions in the wastewater, and the application effect is good; and by setting up an integrated device, the enrichment of copper (II) ions can be achieved in the process of treating copper-containing wastewater, so that its concentration reaches 10,000 mg / L, and then applied to rough refining to obtain high-purity electrolytic copper.

[0124] In summary, the present invention uses copper-based sulfide compounds as electrode materials and other electrodes to form an electrochemical device. The device is an electrocatalytic coupled deionization system with electrochemical oxidation and complex breaking performance, and has a good selective removal effect on copper (II) ions in organic complex copper-containing wastewater, strongly acidic wastewater, and wastewater interfered with by high concentrations of salt ions and heavy metal ions; at the same time, the present invention further uses copper-based sulfide compounds as anode and cathode active materials to form a counter electrode, which is assembled with an anion exchange membrane and a power supply to form an electrodialysis reaction device, which can simultaneously carry out copper removal and copper embedding reactions at a lower voltage and a wider pH range. Combined with the electrode regeneration step, the copper extraction operation can be carried out continuously, which greatly improves the copper extraction efficiency, and has high removal efficiency and good selectivity for copper (II) ions in copper-containing wastewater.

[0125] The present invention is further described above with the aid of specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the essence and scope of the present invention. Various modifications made to the above embodiments by ordinary technicians in this field after reading this specification are all within the scope of protection of the present invention.

Claims

1. An electrochemical device for extracting copper from copper-containing wastewater, It is characterized in that The anode material of the electrochemical device is activated carbon, graphite, lead dioxide, BDD, Cu m X 1-a-b Y a Z b The cathode material is one of CunX1-c-dYcZd and carbon-selenium composite materials. After the anode and cathode are connected to the power supply, it is used to treat copper-containing wastewater; Among them, 1<m≤2, 1≤n<2, and m>n; 0≤a≤1, 0≤b≤1 and 0≤a+b≤1; 0≤c≤1, 0≤d≤1 and 0≤c+d≤1; X, Y, Z are selected from one of S, Se, and Te.

2. The electrochemical device for extracting copper from copper-containing wastewater according to claim 1, It is characterized in that The anode material of the electrochemical device is one of activated carbon, graphite, lead dioxide, and BDD material; the cathode material is one of copper selenide, copper selenide sulfide, and carbon-selenium composite material. The anode and cathode are connected to a power supply and a direct current of 0.6-4.0V is applied, and the device is used to treat acidic electroplating wastewater containing Cu-EDTA.

3. The electrochemical device for extracting copper from copper-containing wastewater according to claim 2, It is characterized in that The preparation steps of the copper selenide material are as follows: Selenium powder is stirred and dissolved in hydrazine hydrate to obtain mixture A; ethanol and water are mixed in proportion, anhydrous cupric chloride is added and stirred to dissolve, to obtain mixture B; A and B are mixed and stirred to obtain a mixture, and the mixture is placed in an oven, heated to 150-200° C. and reacted for 20-30 hours to obtain a crude copper selenide product.

4. The electrochemical device for extracting copper from copper-containing wastewater according to claim 3, It is characterized in that The molar ratio of the selenium powder to anhydrous cupric chloride is 1:

1.

5. The electrochemical device for extracting copper from copper-containing wastewater according to claim 2, It is characterized in that The cathode electrode is obtained by the following method: Conductive carbon black and copper selenide material are mixed evenly, then added into a solvent and stirred, and after adding a binder, stirring is continued until a uniform mixture is obtained; the obtained mixture is coated on graphite paper, and the coated graphite paper is dried at 60°C overnight to finally obtain a cathode electrode having copper selenide as an active material.

6. The electrochemical device for extracting copper from copper-containing wastewater according to claim 2, It is characterized in that The anode electrode is obtained by the following method: conductive carbon black and activated carbon material are mixed evenly, then added into a solvent and stirred, a binder is added and stirred until a uniform mixture is obtained; the obtained mixture is coated on graphite paper, and the coated graphite paper is dried at 60° C. overnight to finally obtain the anode electrode.

7. The electrochemical device for extracting copper from copper-containing wastewater according to claim 1, It is characterized in that The electrochemical device also includes an anion exchange membrane.

8. A method for extracting copper from copper-containing wastewater, It is characterized in that The electrochemical device according to any one of claims 1 to 7 is used to extract copper from copper-containing wastewater by an electrochemical method.

9. The method for extracting copper from copper-containing wastewater according to claim 8, It is characterized in that The method comprises the following steps: (1) Simultaneous copper embedding and copper removal process: Using electrodialysis reactor mode, Cu m X 1-a-b Y a Z b The electrode is used as anode, with Cu n X 1-c-d Y c Z d The electrode is used as the cathode, and the anode and the cathode are separated by an anion exchange membrane. A supporting electrolyte salt solution is added to the anode chamber, and the copper-containing wastewater to be treated is added to the cathode chamber. After power is turned on, a copper-rich electrode is formed at the cathode, and a copper-deficient electrode is formed at the anode. A high-concentration copper-containing solution is obtained in the anode chamber, and copper ions (II) in the copper-containing wastewater in the cathode chamber are selectively adsorbed onto the cathode material. (2) Regeneration process: After the reaction in step (1) is completed, the positive and negative poles of the power supply are switched to perform electrode exchange, the solution in the anode chamber after the electrode exchange is replaced with a fresh supporting electrolyte salt solution, and the solution in the cathode chamber after the electrode exchange is replaced with copper-containing wastewater, and the power is turned on again to perform anode copper removal and cathode copper embedding, thereby achieving copper extraction from the copper-containing wastewater and completing the cyclic regeneration of the electrode; Among them, 1<m≤2, 1≤n<2, and m>n; 0≤a≤1, 0≤b≤1 and 0≤a+b≤1; 0≤c≤1, 0≤d≤1 and 0≤c+d≤1; X, Y, Z are selected from one of S, Se, and Te.

10. The method for extracting copper from copper-containing wastewater according to claim 9, It is characterized in that The method comprises the following steps: (1) Simultaneous copper embedding and copper removal process: Using electrodialysis reactor mode, Cu 2 Se electrode is used as the anode, CuSe electrode is used as the cathode, the anode and cathode are separated by an anion exchange membrane, a supporting electrolyte salt solution is added to the anode chamber, and a copper-containing wastewater solution to be treated is added to the cathode chamber; after power is turned on, the copper (II) ions in the copper-containing wastewater in the cathode chamber are embedded into the cathode material to form a copper-rich Cu 2 Se electrode, while Cu as the anode active material 2 Se loses copper (I) ions and becomes a copper-deficient CuSe electrode; a high-concentration copper-containing solution is obtained in the anode chamber, and copper (II) ions in the copper-containing wastewater passed into the cathode chamber will be selectively adsorbed onto the cathode material. (2) Regeneration process: After the reaction in step (1) is completed, the positive and negative electrodes of the power supply are switched to exchange the electrodes, and the copper-rich Cu generated in step (1) is used as the 2 Se electrode as the anode, the copper-deficient CuSe electrode generated in step (1) as the cathode, and the copper-rich Cu 2 The solution in the anode chamber where the Se electrode is located is replaced with a fresh supporting electrolyte salt solution, and the solution in the cathode chamber where the copper-deficient CuSe electrode is located is replaced with copper-containing wastewater; power is turned on again to perform anode copper removal and cathode copper embedding, thereby realizing the extraction of copper from the copper-containing wastewater and completing the cyclic regeneration of the electrode.

11. The method for extracting copper from copper-containing wastewater according to claim 9 or 10, It is characterized in that After completing step (1) or (2), the high-concentration copper-containing solution in the anode chamber is collected and used for electrolytic refining of crude copper after impurities are removed.

12. The method for extracting copper from copper-containing wastewater according to claim 11, It is characterized in that The concentration of copper (II) ions in the high-concentration copper-containing solution is above 10000 mg / L, and the impurity removal method is electrolysis.

13. The method for extracting copper from copper-containing wastewater according to claim 9 or 10, It is characterized in that In step (1) and step (2), the voltage of the power supply is 0.1-1.4V, and the power supply time is 60-180min.

14. The method for extracting copper from copper-containing wastewater according to claim 10, It is characterized in that In step (1), the Cu 2 Se electrode is made of Cu 2 Se, conductive carbon material and binder PVDF are mixed in a mass ratio of 7-9:2-0.5:1-0.

5.

15. The method for extracting copper from copper-containing wastewater according to claim 10, It is characterized in that In step (1), the CuSe electrode is prepared by mixing CuSe, a conductive carbon material and a binder PVDF in a mass ratio of 7-9:2-0.5:1-0.

5.

16. The method for extracting copper from copper-containing wastewater according to claim 14 or 15, It is characterized in that The conductive carbon material is selected from one or more of acetylene black, carbon nanotubes, graphene, graphite and carbon fiber.

17. The method for extracting copper from copper-containing wastewater according to claim 9 or 10, It is characterized in that In step (1) and step (2), the supporting electrolyte salt solution is a sulfate solution or a chloride solution, the concentration of sulfate in the sulfate solution is 0.1-2 mol / L, and the concentration of chloride ions in the chloride solution is 0.1-2 mol / L.

18. The method for extracting copper from copper-containing wastewater according to claim 9 or 10, It is characterized in that The step (2) is repeated 10-20 times.

19. The method for extracting copper from copper-containing wastewater according to any one of claims 8 to 10, It is characterized in that The copper-containing wastewater is one of electroplating acidic wastewater, comprehensive discharge wastewater generated by circuit board printing, copper-containing wastewater from copper smelting, and copper-containing wastewater after chelation.

20. The method for extracting copper from copper-containing wastewater according to claim 19, It is characterized in that The copper (II) ion concentration in the copper-containing wastewater is 0.5-10000 mg / L; the pH value of the copper-containing wastewater is 0.1-5.0.

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