Method for the electrocatalytic oxidation removal of cyanide complexes of medium-high concentration iron

Abstract

This application provides a method for the electrocatalytic oxidation removal of medium-to-high concentration iron cyanide complexes, belonging to the field of ferric cyanide wastewater treatment. This application involves adding a chlorine-containing electrolysis promoter to wastewater containing medium-to-high concentrations of iron cyanide complexes to obtain a solution to be electrolyzed; using a platinum-titanium electrode or a ruthenium-iridium-titanium electrode as the anode and a foamed copper electrode as the cathode, the solution to be electrolyzed is subjected to electrocatalytic oxidation treatment; during the electrocatalytic oxidation process, a pH adjuster is used to maintain the pH of the liquid phase >10; after the electrocatalytic oxidation treatment is completed, solid-liquid separation is performed to obtain filter residue and filtrate. By selecting specific types of anodes and cathodes and adding a chlorine-containing electrolysis promoter, this application can promote the decomposition and transformation of iron cyanide complexes, ultimately converting cyanide into carbonate ions and nitrogen gas, achieving efficient removal of medium-to-high concentrations of iron cyanide complexes safely and environmentally.

Description

Technical Field

[0001] This invention relates to the field of ferric cyanide wastewater treatment technology, specifically to a method for removing medium-to-high concentration iron cyanide complexes by electrocatalytic oxidation. Background Technology

[0002] In the cyanide gold extraction process, Fe is produced by the iron minerals associated with the ore or by corrosion of equipment. 2+ Fe 3+ It will react with cyanide (CN) - Under alkaline conditions, it forms a stable ferrocyanide complex ([Fe(CN)6]). 4- ) and ferricyanide complex ([Fe(CN)6]) 3- The former can be oxidized to the latter. These two complexes have extremely high stability constants (35.4 and 42.0 respectively), making them difficult to decompose under normal conditions. This leads to their long-term retention in cyanide tailings, forming ferricyanide wastewater containing medium to high concentrations of cyanide complexes. Although the toxicity of these two iron cyanide complexes is lower than that of free cyanide, under certain conditions (such as strong acids, ultraviolet radiation, and high temperatures), they may decompose and release highly toxic CN. - Iron cyanide compounds accumulate in water and soil, threatening ecosystems and human health. Therefore, it is necessary to remove iron cyanide complexes from ferricyanide wastewater.

[0003] Currently, methods for removing medium- to high concentrations of iron cyanide complexes mainly include chemical precipitation, adsorption, pyrolysis, and electrolysis. Chemical precipitation involves adding heavy metal ions to react with ferrous or ferric cyanide complexes to form insoluble complex salt precipitates. However, this method requires strict pH control to prevent precipitate dissolution and secondary leaching, making it challenging to control. Adsorption utilizes the surface adsorption or ion exchange of porous adsorbent materials (such as activated carbon, zeolite, ion exchange resins, and nanomaterials) to adsorb iron cyanide complexes from solution. However, the capacity of adsorbent materials is limited, requiring regeneration or replacement, resulting in high costs. Pyrolysis involves adding a catalyst to soil or waste containing iron cyanide complexes and heating to 300–550°C for catalytic thermal decomposition to remove the iron cyanide complexes. The drawback of this method is the need for high-temperature thermal decomposition, making the process complex. Electrolysis removes iron cyanide complexes by setting a fixed electric field, causing charged particles to move and react under the influence of the electric field force. This method is currently a key research focus.

[0004] In the prior art, patent CN118702366A discloses an electrolytic method for removing iron cyanide complexes. This patent involves adding concentrated acid to wastewater containing iron cyanide complexes to adjust the pH of the solution to a predetermined range; using a DC electrolysis device to electrolyze the wastewater; and using NaOH solution for tail gas absorption to remove the iron cyanide complexes from the wastewater. However, the electrolysis method provided by this patent requires acidic conditions to remove the iron cyanide complexes, posing a certain risk of hydrogen cyanide spillage. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides a method for electrocatalytic oxidation to remove cyanide complexes of iron at medium and high concentrations, aiming to enable the safe and efficient removal of cyanide complexes of iron in ferricyanide wastewater under alkaline conditions.

[0006] This application provides a method for electrocatalytic oxidation to remove cyanide complexes with medium to high concentrations of iron, comprising the following steps: An electrolysis promoter was added to wastewater containing cyanide complexes with medium to high concentrations of iron to obtain a solution to be electrolyzed. The solution to be electrolyzed is subjected to electrocatalytic oxidation treatment using a platinum titanium electrode or a ruthenium iridium titanium electrode as the anode and a foamed copper electrode as the cathode; during the electrocatalytic oxidation treatment, a pH adjuster is used to make the pH value of the liquid phase >10. After the electrocatalytic oxidation treatment is completed, solid-liquid separation is performed to obtain filter residue and filtrate.

[0007] As a further improvement of this application, the amount of the electrolysis promoter added is 1~3 g / L.

[0008] As a further improvement of this application, the electrocatalytic oxidation treatment is performed using a DC power supply, and the electrolysis is carried out in constant current mode or constant voltage mode.

[0009] As a further improvement of this application, the current in the constant current mode is 3.0~6.0 A.

[0010] As a further improvement of this application, the voltage of the constant voltage mode is 3.0~6.0 V.

[0011] As a further improvement of this application, the electrocatalytic oxidation time is 4-8 h.

[0012] As a further improvement of this application, the electrocatalytic oxidation process also includes an aeration process.

[0013] As a further improvement to this application, the electrolysis promoter includes one of sodium chloride, potassium chloride, calcium chloride, and magnesium chloride.

[0014] As a further improvement of this application, the pH adjuster includes one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, potassium carbonate, trisodium phosphate, tripotassium phosphate, sodium metasilicate, and lime.

[0015] As a further improvement of this application, the iron content in the wastewater is 500~2000 mg / L, and the cyanide content is 1000~5000 mg / L.

[0016] The beneficial effects of this application include: The method for removing medium-to-high concentration iron cyanide complexes by electrocatalytic oxidation provided in this application utilizes a platinum-titanium electrode or a ruthenium-iridium-titanium electrode as the anode and a copper foam electrode as the cathode. A chlorine-containing electrolysis promoter is added to the wastewater. The copper foam electrode, acting as the cathode, weakens the stability of the Fe-C coordination bonds in the iron cyanide complexes, promoting their dissociation and releasing free cyanide ions. Simultaneously, the chloride ions provided by the electrolysis promoter generate intermediate active substances at the anode under alkaline conditions, which react with the released free cyanide ions, ultimately causing iron ions to precipitate and cyanide to be converted into carbonate ions and nitrogen gas. This method safely and environmentally friendly achieves highly efficient removal of medium-to-high concentration iron cyanide complexes.

[0017] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0019] Figure 1 The images shown are actual pictures of the ferricyanide wastewater treated in the embodiments of this application. Figure 2 This is a photograph of the filter residue obtained after solid-liquid separation in the embodiments of this application. Figure 3 The image shows the XRD pattern of the filter residue obtained after solid-liquid separation in the embodiments of this application. Detailed Implementation

[0020] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] Existing electrolytic methods require acidic conditions to remove medium-to-high concentrations of iron cyanide complexes, but this method carries the risk of hydrogen cyanide spillage. To achieve safer and more environmentally friendly efficient removal of medium-to-high concentrations of iron cyanide complexes, this application provides a method for electrocatalytic oxidation. By selecting specific types of anodes and cathodes and adding a chlorine-containing electrolysis promoter to the wastewater, the decomposition and transformation of iron cyanide complexes can be promoted, ultimately converting cyanide into carbonate ions and nitrogen gas, thus achieving safe and environmentally friendly efficient removal of medium-to-high concentrations of iron cyanide complexes.

[0024] Specifically, embodiments of this application provide a method for electrocatalytic oxidation to remove cyanide complexes with medium to high concentrations of iron, comprising the following steps: A chlorine-containing electrolysis promoter is added to wastewater containing cyanide complexes with medium to high concentrations of iron to obtain a solution to be electrolyzed. Using a platinum titanium electrode or a ruthenium iridium titanium electrode as the anode and a foamed copper electrode as the cathode, the electrolyte solution is subjected to electrocatalytic oxidation treatment; during the electrocatalytic oxidation treatment, a pH adjuster is used to keep the pH of the liquid phase >10; After the electrocatalytic oxidation treatment is completed, solid-liquid separation is performed to obtain filter residue and filtrate.

[0025] In the technical solution of this application embodiment, the foamed copper electrode, serving as the cathode, is a porous electrode. Its porous structure optimizes the "electrode-electrolyte interface reaction," increasing the number of active sites, improving the reaction rate, and optimizing mass transfer efficiency. Its pore structure forms a "three-dimensional conductive network," effectively improving the electron conduction path. Simultaneously, d-orbital electrons on the copper surface can be injected into the empty antibonding orbitals of the cyano group via feedback bonds. When negative potential polarization is applied using foamed copper as the cathode, this electron injection effect is enhanced, weakening the originally stable Fe-C coordination bond in the iron cyanide complex, causing a reduction and dissociation reaction, and forcing the originally stable complex to release free cyanide ions (CN). - Meanwhile, the platinum-titanium electrode or ruthenium-iridium-titanium electrode selected in this application belongs to titanium-based coated electrode materials with low chlorine evolution overpotential. Combined with the chlorine-containing electrolysis promoter selected in this application and the alkaline conditions of the reaction process, the chloride ions provided by the electrolysis promoter can lose electrons at the anode surface with a high positive potential, undergoing an oxidation reaction, and generating an intermediate active substance (ClO) under conditions of pH > 10. - The released free cyanide ions (CN) - It is easily and rapidly oxidized to CNO by intermediate active substances. - And eventually converted into CO3 2- The specific conversion path for N2 is as follows: CN - +2ClO - +H2O→CNO - +2Cl - +2OH - 2CNO - +3ClO - +2OH - →2CO3² - +N2↑+3Cl - +H2O As can be seen from the above, this application achieves the safe and environmentally friendly efficient removal of medium-to-high concentration iron cyanide complexes through the combined action of specific types of cathode and anode materials, chlorine-containing electrolysis promoters, and alkaline conditions. Furthermore, the method provided in this application is simple to operate, has a high removal rate of iron cyanide complexes, and utilizes existing electrode materials such as platinum-titanium, ruthenium-iridium-titanium, and foamed copper electrodes. The raw materials are also readily available, and the corresponding electrocatalytic oxidation reaction can occur at room temperature, demonstrating high practical application value.

[0026] Furthermore, in some embodiments, the amount of electrolysis promoter added is 1~3 g / L.

[0027] In the technical solution of this application embodiment, the chloride ions provided by the electrolysis promoter can generate intermediate active substances at the anode and react with free cyanide ions to ultimately convert them into CO3. 2- And N2. The amount of electrolysis accelerator determines the yield of intermediate active substances, which in turn affects the removal efficiency of iron cyanide complexes. This application optimizes the amount of electrolysis accelerator added to promote the conversion of cyanide ions, thereby improving the removal rate of iron cyanide complexes.

[0028] More specifically, in this application, the chlorine-containing electrolysis promoter refers to a substance capable of ionizing chloride ions, preferably a chloride, and more preferably one of sodium chloride, potassium chloride, calcium chloride, and magnesium chloride. By ionizing the electrolysis promoter to release chloride ions, intermediate active substances can be generated at the anode using the chloride ions.

[0029] Furthermore, in some embodiments, the electrocatalytic oxidation treatment is performed using a DC power supply, and the electrolysis is conducted in either a constant current mode or a constant voltage mode. The current in the constant current mode is preferably 3.0–6.0 A; the voltage in the constant voltage mode is preferably 3.0–6.0 V; and the electrolysis time is 4–8 h.

[0030] In the technical solution of this application embodiment, by optimizing the conditions during electrocatalytic oxidation treatment, it is beneficial to improve the removal effect of iron cyanide complexes.

[0031] Furthermore, in some embodiments, the electrocatalytic oxidation process also includes an aeration process.

[0032] In the technical solution of this application embodiment, aeration treatment is beneficial to accelerate the reaction rate. Specifically, the aeration rate during aeration treatment is preferably 1~4 mL / min.

[0033] Furthermore, in some embodiments, the pH adjuster includes one of sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, potassium carbonate, trisodium phosphate, tripotassium phosphate, sodium metasilicate, and lime.

[0034] In the technical solution of this application embodiment, by using a pH adjuster to adjust the liquid phase pH value to >10 during the electrocatalytic oxidation process, it is beneficial to promote the generation of ClO by chloride ions at the anodic reaction. - This, in turn, prompted CN - Ultimately converted into CO3 2-The presence of N2 effectively avoids the generation of harmful hydrogen cyanide gas, improving the safety of the treatment process. More specifically, in practical applications, the aforementioned pH adjuster can be dissolved in water to prepare an alkaline solution, which is then added to adjust the pH value. During the electrocatalytic oxidation process, the method of adding the pH adjuster and its dosage can be adjusted according to the actual situation, ensuring that the pH value of the liquid phase remains >10 throughout the entire reaction process.

[0035] Furthermore, in some embodiments, the iron content in the wastewater is 500~2000 mg / L, and the cyanide content is 1000~5000 mg / L.

[0036] In the technical solution of this application embodiment, it can achieve a good removal effect on wastewater containing cyanide complexes with medium to high concentrations of iron.

[0037] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0038] Example 1 This embodiment provides a method for electrocatalytic oxidation to remove cyanide complexes with medium to high concentrations of iron, comprising the following steps: S1. The ferric cyanide-containing wastewater (its physical diagram is shown below) Figure 1 (As shown) is added to the electrolytic cell, and then potassium chloride, an electrolysis promoter, is added to the wastewater at a dosage of 2 g / L to obtain the solution to be electrolyzed.

[0039] S2. Select existing ruthenium-iridium-titanium electrode material as the anode and existing foamed copper electrode material as the cathode, and assemble them with a DC power supply to form an electrocatalytic oxidation reactor. Then, place the anode and cathode into the solution to be electrolyzed and aerate (aeration rate of 4 mL / min). Set the electrolysis mode to constant current mode and perform electrocatalytic oxidation with a constant current of 5.0 A for 6 h. During this process, continuously monitor the pH value of the liquid phase in the electrolytic cell, and continuously add alkaline solution (10% potassium hydroxide solution) to the electrolytic cell to keep the pH value of the liquid phase always >10.

[0040] S3. After the electrocatalytic oxidation treatment is completed, filter residue and filtrate are obtained through filtration.

[0041] In this embodiment, the pollutant composition analysis results of the ferric cyanide wastewater used in step S1 and the composition analysis results of the filtrate obtained in step S3 are shown in Table 1 and Table 2, respectively.

[0042] Table 1. Pollutant composition analysis results of ferric cyanide-containing wastewater in Example 1 Table 2. Component analysis results of the filtrate obtained in Example 1. In Tables 1 and 2, CN T This indicates total cyanide.

[0043] In this embodiment, the actual image of the dried filter residue obtained in step S3 is shown below. Figure 2 As shown, it appears reddish-brown; XRD analysis of the filter residue yielded the following results: Figure 3 As shown, it was confirmed to be Fe2(OH)2CO3. Combined with the component analysis results of the filtrate, it can be inferred that the cyanide was ultimately converted into CO3. 2- And N2, and calculated that the removal rate of iron cyanide complex was 82.8%.

[0044] The formula for calculating the removal rate of iron cyanide complexes is as follows: Removal rate of iron cyanide complexes = [1 - (Concentration of Fe in filtrate / Concentration of Fe in ferricyanide wastewater)] 100%.

[0045] In the various embodiments and comparative examples of this application, the removal rate of iron cyanide complexes was calculated according to the above formula, which will not be repeated below.

[0046] Example 2 This embodiment provides a method for the electrocatalytic oxidation removal of cyanide complexes with medium to high concentrations of iron. Compared with Example 1, the only difference is the anode used in step S2. In this embodiment, an existing platinum-titanium electrode is selected as the anode, and the remaining steps and parameters are the same as in Example 1, and will not be repeated here.

[0047] In this embodiment, the removal rate of iron cyanide complexes was 97.0%, achieving effective removal of iron cyanide complexes.

[0048] Examples 3-4 and Comparative Example 1 Examples 3-4 and Comparative Example 1 respectively provide a method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron. Compared with Example 1, the only difference is the change in the current under constant current mode. The other steps and parameters are the same as in Example 1 and will not be repeated here. The current under constant current mode in Examples 3-4 and Comparative Example 1 and the calculated removal rates of cyanide complexes of iron are shown in Table 3.

[0049] Table 3 Current and removal rate in Examples 3-4 and Comparative Example 1 As shown in Table 3, under constant current mode, the removal rate of iron cyanide complexes increases with increasing current; however, if the current is too low, the removal rate of iron cyanide complexes will decrease. In this application, by preferably using a current of 3.0~6.0A under constant current mode, the removal rate of iron cyanide complexes can reach over 57%; by further preferably using a current of 5.0~6.0A under constant current mode, the removal rate of iron cyanide complexes can reach over 82%.

[0050] Examples 5-7 and Comparative Example 2 Examples 5-7 and Comparative Example 2 respectively provide a method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron. Compared with Example 1, the only difference is that the electrolysis mode is changed from constant current mode to constant voltage mode. The remaining steps and parameters are the same as in Example 1, and will not be repeated here. The voltage in constant voltage mode in Examples 5-7 and Comparative Example 2 and the calculated removal rate of cyanide complexes of iron are shown in Table 4.

[0051] Table 4. Voltage and removal rate in Examples 5-7 and Comparative Example 2 As shown in Table 4, under constant voltage mode, the removal rate of iron cyanide complexes increases with increasing voltage; however, if the voltage is too low, the removal rate of iron cyanide complexes will decrease. In this application, by preferably using a voltage of 3.0~6.0V under constant voltage mode, the removal rate of iron cyanide complexes can reach over 29%; by further preferably using a voltage of 5.0~6.0V under constant voltage mode, the removal rate of iron cyanide complexes can reach over 80%.

[0052] Examples 8-9 Examples 8-9 provide methods for the electrocatalytic oxidation of high-concentration iron cyanide complexes. Compared with Example 1, the only difference is the change in the electrocatalytic oxidation time in step S2. The remaining steps and parameters are the same as in Example 1 and will not be repeated here. The electrocatalytic oxidation time and the calculated removal rate of iron cyanide complexes in Examples 8-9 are shown in Table 5.

[0053] Table 5. Electrocatalytic oxidation time and removal rate in Examples 8-9 As shown in Table 5, the electrocatalytic oxidation time affects the removal rate of iron cyanide complexes. This application optimizes the electrocatalytic oxidation time to 4–8 h, achieving a removal rate of over 60% for iron cyanide complexes.

[0054] Examples 10-11 and Comparative Example 3 Examples 10-11 and Comparative Example 3 respectively provide a method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron. Compared with Example 1, the only difference is the change in the dosage of sodium chloride, the electrolysis promoter, in step S1. The remaining steps and parameters are the same as in Example 1 and will not be repeated here. The dosage of the electrolysis promoter in Examples 10-11 and Comparative Example 3 and the calculated removal rate of cyanide complexes of iron are shown in Table 6.

[0055] Table 6. Electrolysis accelerator dosage and removal rate in Examples 10-11 and Comparative Example 3 As shown in Table 6, the dosage of the electrolysis accelerator affects the removal rate of iron cyanide complexes. This application achieves a removal rate of over 36% for iron cyanide complexes by optimizing the electrocatalytic oxidation time to 1-3 g / L.

[0056] Comparative Example 4 Comparative Example 4 provides a method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron. Compared with Example 1, the only difference is that the type of electrolysis promoter in step S1 is changed. The dosage and other steps and parameters are the same as in Example 1, and will not be repeated here.

[0057] In this comparative example, using Na2SO3 as an electrolysis promoter, the final removal rate of iron cyanide complexes was only 7.4%, proving that the electrolysis promoter in this application cannot be arbitrarily selected. Chlorine-free electrolysis promoters cannot promote the electrolysis of iron cyanide complexes in this application, resulting in the iron cyanide complexes being difficult to remove effectively.

[0058] Comparative Examples 5-7 Comparative Examples 5-7 each provide a method for the electrocatalytic oxidation removal of medium-to-high concentration iron cyanide complexes. Compared with Example 1, the only difference is the change of the anode material; the remaining steps and parameters are the same as in Example 1 and will not be repeated here. The anodes in Comparative Examples 5-7 and the calculated removal rates of iron cyanide complexes are shown in Table 7.

[0059] Table 7. Anodes and removal rates in Comparative Examples 5-7 As shown in Table 7, the type of anode material affects the removal rate of iron cyanide complexes. Compared with titanium-iridium-tantalum electrodes, tin-antimony-titanium electrodes, and stainless steel electrodes, the platinum-titanium electrode or ruthenium-iridium-titanium electrode preferred in this application has a low chlorine evolution overpotential. Combined with the chlorine-containing electrolysis promoter in this application, it can significantly improve the removal rate of iron cyanide complexes.

[0060] Comparative Examples 8-10 Comparative Examples 8-10 each provide a method for the electrocatalytic oxidation removal of cyanide complexes of medium to high concentrations of iron. Compared with Example 1, the only difference is the change in the cathode material; the remaining steps and parameters are the same as in Example 1 and will not be repeated here. The cathodes in Comparative Examples 8-10 and the calculated removal rates of iron cyanide complexes are shown in Table 8.

[0061] Table 8. Cathodes and removal rates in Comparative Examples 8-10 Table 8 shows that the type of cathode material affects the removal rate of iron cyanide complexes. Nickel foam electrodes and graphite electrodes do not contain copper, making it difficult to effectively promote the release of free cyanide ions from iron cyanide complexes, resulting in low removal rates. Although copper foil electrodes contain copper, their lack of porous structure means the removal rate of iron cyanide complexes still needs improvement. This application selects copper foam electrodes as cathodes, which synergistically utilize their porous structure and the electron injection effect of copper to significantly improve the removal rate of iron cyanide complexes.

[0062] In summary, this application provides a method for the electrocatalytic oxidation removal of medium-to-high concentration iron cyanide complexes, belonging to the field of ferric cyanide wastewater treatment. This application involves adding a chlorine-containing electrolysis promoter to wastewater containing medium-to-high concentrations of iron cyanide complexes to obtain a solution to be electrolyzed; using platinum titanium or ruthenium-iridium titanium as the anode and copper foam as the cathode, the solution to be electrolyzed is subjected to electrocatalytic oxidation treatment; during the electrocatalytic oxidation process, a pH adjuster is used to maintain the pH of the liquid phase >10; after the electrocatalytic oxidation reaction is completed, solid-liquid separation is performed to obtain filter residue and filtrate. By selecting specific types of anodes and cathodes and adding a chlorine-containing electrolysis promoter, this application can promote the decomposition and transformation of iron cyanide complexes, ultimately converting cyanide into carbonate ions and nitrogen gas, achieving efficient removal of medium-to-high concentrations of iron cyanide complexes safely and environmentally.

[0063] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for electrocatalytic oxidation removal of cyanide complexes of medium and high concentration of iron, characterized by that, Includes the following steps: A chlorine-containing electrolysis promoter is added to wastewater containing cyanide complexes with medium to high concentrations of iron to obtain a solution to be electrolyzed. The solution to be electrolyzed is subjected to electrocatalytic oxidation treatment using a platinum titanium electrode or a ruthenium iridium titanium electrode as the anode and a foamed copper electrode as the cathode; during the electrocatalytic oxidation treatment, a pH adjuster is used to make the pH value of the liquid phase >10. After the electrocatalytic oxidation treatment is completed, solid-liquid separation is performed to obtain filter residue and filtrate.

2. The method for electrocatalytic oxidation removal of cyanide complexes of medium and high concentration of iron according to claim 1, characterized by that, The amount of the electrolysis accelerator added is 1~3 g / L.

3. The method for electro-catalytic oxidation removal of cyanide complex of medium-high concentration iron according to claim 1, characterized in that, During the electrocatalytic oxidation treatment, a DC power supply is used for electrolysis, and a constant current mode or a constant voltage mode is used during electrolysis.

4. The method for electrocatalytic oxidation removal of cyanide complexes of medium-high concentration of iron according to claim 3, characterized by the fact that, The constant current mode has a current of 3.0~6.0 A.

5. The method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron according to claim 3, characterized in that, The voltage in the constant voltage mode is 3.0~6.0 V.

6. The method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron according to claim 1, characterized in that, The electrocatalytic oxidation time is 4-8 h.

7. The method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron according to claim 1, characterized in that, The electrocatalytic oxidation process also includes an aeration process.

8. The method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron according to claim 1, characterized in that, The electrolysis accelerator includes one of sodium chloride, potassium chloride, calcium chloride, and magnesium chloride.

9. The method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron according to claim 1, characterized in that, The pH adjuster includes one of the following: sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, potassium carbonate, trisodium phosphate, tripotassium phosphate, sodium metasilicate, and lime.

10. The method for electrocatalytic oxidation to remove cyanide complexes of medium to high concentrations of iron according to claim 1, characterized in that, The wastewater contains 500-2000 mg / L of iron and 1000-5000 mg / L of cyanide.

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