Method for photocatalytic dissolution of copper in electronic waste

Abstract

The invention discloses a method for dissolving copper in electronic waste through photocatalysis, and belongs to the technical field of photocatalysis and electronic waste recovery. The invention provides a method for photocatalytic dissolution of copper in electronic waste. The method comprises the following steps: uniformly mixing a transition metal porphyrin polymer, an aqueous solution of ammonium salt and hydrogen peroxide to obtain a mixed solution; the transition metal porphyrin polymer is obtained by taking N 'N-dimethylformamide as a solvent, adding 5, 10, 15, 20-tetra (4-carboxyphenyl) porphyrin, a transition metal source and glacial acetic acid and carrying out hydrothermal reaction; and adding the copper-containing electronic waste into the mixed solution, and dissolving the copper in the electronic waste under the action of visible light at 20-40 DEG C under normal pressure. In a water phase system, high-selectivity and high-efficiency dissolution of the copper in the electronic waste is realized by virtue of visible light, and a foundation is laid for technical application of photocatalytic recovery of the copper in the electronic waste.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalysis and electronic waste recycling, and more particularly to a method for photocatalytically dissolving copper in electronic waste. Background Art

[0002] Copper, with its high electrical and thermal conductivity and ductility, is a key metal in demand for the development of industries such as electric vehicles, artificial intelligence devices, and power grids. However, due to declining copper ore grades and geopolitical uncertainties, traditional copper mining is no longer able to meet the growing demand. Traditional copper smelting methods include pyrometallurgical and hydrometallurgical methods, but each has its own drawbacks: pyrometallurgical methods are highly energy-intensive, highly polluting, and are only suitable for high-grade sulfide ores. While hydrometallurgical methods can extract copper from low-grade ores, they often face equipment corrosion, high wastewater treatment costs, and low extraction efficiency for high-sulfur composite ores. While electrolytic copper smelting can produce high-purity copper, it is subject to high costs, anode passivation, and impurity accumulation. Electronic waste, such as printed circuit boards and other electronic products, contains an average copper content of up to 23.37%, representing a potential source of copper extraction.

[0003] Current methods for extracting copper from electronic waste include physical, mechanical, chemical, pyrometallurgical, hydrometallurgical, biological, microwave, and supercritical extraction. These methods all face challenges such as poor selectivity, complex procedures, demanding extraction conditions, high costs, limited adaptability, and significant environmental pollution. Photocatalytic technology, by optimizing catalyst performance, generates oxidizing free radicals within the electronic waste extraction system, enabling efficient oxidative dissolution of the copper. Compared to traditional methods, this process avoids high temperatures and high pressures, consumes less energy, and effectively reduces environmental pollution. The key to photocatalytic dissolution of copper from electronic waste is achieving efficient oxidative dissolution of copper in green solvents. Currently, most photocatalytic metal dissolution processes are performed in organic solvents such as acetonitrile, dichloromethane, or mixtures of acetonitrile and water. These solvents are highly volatile as the system temperature rises during the photocatalytic dissolution process, resulting in solution loss. This evaporation into the air can affect copper dissolution efficiency and operator health. Summary of the Invention

[0004] To address the above issues, the present invention provides a method for photocatalytic dissolution of copper in electronic waste. In an aqueous solution of ammonium salt, visible light is used to achieve highly selective and efficient dissolution of copper in electronic waste, laying the foundation for the technical application of photocatalytic recovery of copper in electronic waste.

[0005] The object of the present invention is to provide a method for photocatalytically dissolving copper in electronic waste, comprising the following steps: A transition metal porphyrin polymer, an aqueous solution of an ammonium salt and hydrogen peroxide are uniformly mixed to obtain a mixed solution; the transition metal porphyrin polymer is obtained by using N'N-dimethylformamide as a solution, adding 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, a transition metal source and glacial acetic acid, and performing a hydrothermal reaction at 130°C to 150°C.

[0006] Copper-containing electronic waste is added to a mixed solution. Under the action of visible light at room temperature and pressure, transition metal porphyrin polymer acts as a catalyst, and copper and ammonium salt are coordinated to dissolve the copper in the electronic waste at 20℃~40℃ and normal pressure.

[0007] In a preferred embodiment of the present invention, the ammonium salt is ammonium chloride or ammonium phosphate. Preferably, the present invention selects ammonium chloride for use.

[0008] In a preferred embodiment of the present invention, the transition metal porphyrin polymer is a transition metal carboxyl porphyrin polymer (manganese carboxyl porphyrin polymer, zinc carboxyl porphyrin polymer, iron carboxyl porphyrin polymer, cobalt carboxyl porphyrin polymer, nickel carboxyl porphyrin polymer) or a transition metal pyridyl porphyrin polymer (cobalt pyridyl porphyrin polymer); the transition metal is manganese, zinc, iron, cobalt or nickel; further, the transition metal porphyrin polymer is a transition metal carboxyl porphyrin polymer, and further, the transition metal porphyrin polymer is a manganese carboxyl porphyrin polymer.

[0009] Preferably, manganese is selected for use in the present invention.

[0010] In a preferred embodiment of the present invention, the mass ratio of the transition metal porphyrin polymer to the copper-containing electronic waste is 20 mg:0.25 g~1 g.

[0011] In a preferred embodiment of the present invention, the total volume of copper-containing electronic waste, the aqueous solution of ammonium salt, and hydrogen peroxide is 1g: 50mL~200mL, and the concentration of the aqueous solution of ammonium salt is 0.1 mol / L. It should be noted that, considering that the solution in the system will have evaporation loss after illumination, an additional 1mL~2mL of water will be added based on the calculated amount of solution. Taking the present invention as an example, the total volume of the aqueous solution of ammonium salt and hydrogen peroxide is 50mL. Calculations are made for other raw materials. Taking into account the problem of evaporation loss, the total volume of the aqueous solution of ammonium salt and hydrogen peroxide is controlled to 52mL.

[0012] In a preferred embodiment of the present invention, the mass concentration of hydrogen peroxide in the aqueous ammonium salt solution is 5% to 15%. It should be noted that this mass concentration refers to the mass concentration of hydrogen peroxide in the entire solution of 5% to 15%. For example, if the experiment uses a mass concentration of 30% hydrogen peroxide, it is diluted to a final concentration of 5% or 15%.

[0013] In a preferred embodiment of the present invention, the dissolution temperature is 35°C to 40°C.

[0014] In a preferred embodiment of the present invention, the dissolution time is 12h~24h.

[0015] In a preferred embodiment of the present invention, when preparing the transition metal porphyrin polymer, the hydrothermal reaction time is 20 hours to 24 hours.

[0016] In a preferred embodiment of the present invention, the copper-containing electronic waste is a copper-containing electronic printed circuit board or copper-clad laminate.

[0017] Compared with the prior art, the present invention has the following beneficial effects: Transition metal porphyrin polymers have excellent light absorption units and porous structures. Under visible light irradiation conditions, the coordination of copper is enhanced through the central nitrogen of the porphyrin ring, and relying on their excellent light-harvesting properties to produce oxygen anions and more catalytic active sites, efficient photocatalytic dissolution of copper in electronic waste in an aqueous system at room temperature and pressure is achieved.

[0018] Under visible light irradiation, transition metal porphyrin polymers generate photogenerated electrons and photogenerated holes. The photogenerated electrons react with hydrogen peroxide to produce superoxide anion radicals·O2⁻, which oxidize copper in electronic waste to Cu 2+ , the ammonium salt in the solution dissociates into NH4 + and the corresponding anion, NH4 + and the corresponding anions with Cu 2+ Forming complex ions, taking ammonium chloride as an example, the complex ion [CuCl4] 2- and copper ammonia complex ions, and under the action of hydrogen peroxide and holes, the copper complex ions are oxidized to CuO and Cu(OH)2, and converted into Cu in the solution under acidic conditions. 2+ By means of the coordination effect between copper and ammonium salt, highly selective dissolution of copper ions is achieved. At the same time, efficient oxidative dissolution of copper is achieved under the oxidation effect of superoxide anion radicals and holes generated during the photocatalytic process.

[0019] The present invention is carried out in a pure water phase system, and the solvent is water, which is significantly different from the strong acid used in the traditional wet smelting process, especially in terms of equipment corrosiveness and environmental pollution. The present invention has significant green and environmentally friendly characteristics.

[0020] The present invention involves oxidative dissolution of copper under visible light irradiation conditions at room temperature and pressure, which will greatly improve the efficiency and cost of utilizing sunlight in subsequent applications. The present invention converts copper in electronic waste into free copper ions rather than complex copper complexes, facilitating subsequent simple reduction to recover high-purity copper. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 3 is a diagram showing the dissolution efficiency of copper in waste printed circuit boards by manganese carboxyl porphyrin polymer in different systems, wherein illustration a is a diagram showing the state just after the addition of manganese carboxyl porphyrin polymer in Example 1, and illustration b is a diagram showing the state after the photocatalytic reaction of manganese carboxyl porphyrin polymer in Example 1 is completed.

[0022] Figure 2 This is a graph showing the dissolution efficiency of copper in waste printed circuit boards by manganese carboxyl porphyrin polymer at different temperatures.

[0023] Figure 3 This is a graph showing the dissolution efficiency of copper in waste printed circuit boards by manganese carboxyl porphyrin polymer in the presence of different inorganic salts.

[0024] Figure 4 This is a graph showing the dissolution efficiency of copper in waste printed circuit boards by manganese carboxyl porphyrin polymer at different hydrogen peroxide concentrations.

[0025] Figure 5 This is a diagram showing the dissolution efficiency of copper in waste printed circuit boards by manganese carboxyl porphyrin polymer at different solid-liquid ratios.

[0026] Figure 6 The figure shows the dissolution efficiency of copper in waste printed circuit boards by cobalt pyridylporphyrin polymer at different solid-liquid ratios.

[0027] Figure 7 This is a graph showing the proportion of copper and other metals in electronic waste dissolved by manganese carboxyl porphyrin.

[0028] Figure 8 This is a diagram showing the dissolution efficiency of copper in printed circuit boards photocatalyzed by different metal carboxyl porphyrin polymers.

[0029] Figure 9 These are photos of the solution colors before and after the photocatalytic dissolution of copper in the printed circuit board by manganese carboxyl porphyrin polymer. Among them, a is the color of the solution just after the addition of manganese carboxyl porphyrin polymer; b is the color of the solution after 12 hours of photocatalysis by manganese carboxyl porphyrin polymer.

[0030] Figure 10 is the stability of manganese carboxyl porphyrin polymer (35℃), where (a) is the photocatalytic copper dissolution efficiency of manganese carboxyl porphyrin polymer after repeated use for 5 times; (b) is the infrared spectrum of manganese carboxyl porphyrin polymer before and after photocatalytic reaction. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] The preparation methods of the transition metal carboxyl porphyrin polymer catalyst and cobalt pyridyl porphyrin polymer used in the present invention are as follows. The present invention improves the solubility of the carboxyl porphyrin in the N,N-dimethylformamide solution by ultrasonicating the carboxyl porphyrin. At the same time, glacial acetic acid is used to increase the solubility of the metal salt in the prepared solution, thereby enhancing the reactivity of the free carboxyl porphyrin with the metal salt, thereby obtaining the metal carboxyl porphyrin polymer.

[0033] (1) The preparation process of manganese carboxyl porphyrin polymer catalyst is as follows: Accurately weigh 0.1 mmol, 0.0791 g of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a 50 mL beaker was added, and 9 mL of N,N-dimethylformamide (DMF) was added. The mixture was ultrasonicated at room temperature for 10 min, followed by 0.245 g of manganese acetate tetrahydrate (Mn(CH3COO)2·4H2O). 0.5 mL of 6 mol / L glacial acetic acid was then added, and the mixture was ultrasonicated at room temperature for another 10 min. The mixture was then transferred to the polytetrafluoroethylene liner of an autoclave, quickly transferred to the sealed autoclave, and heated at 130°C for 24 h. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL DMF at a speed of 8000 r / min for a single time of 3 minutes, and the supernatant is aspirated with a disposable dropper; then the solid is washed three times with 5-10 mL deionized water at a speed of 8000 r / min for a single time of 3 minutes, and finally the solid material after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for a single time of 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain manganese carboxyl porphyrin polymer (Mn TCPPploy).

[0034] (2) The preparation process of zinc carboxyl porphyrin polymer is as follows: Accurately weigh 0.1 mmol, 0.0791 g of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a 50 mL beaker. Add 9 mL of N,N-dimethylformamide (DMF) and sonicate at room temperature for 10 min. Then add 0.2195 g of zinc acetate dihydrate (Zn(CH3COO)2·2H2O). Then, add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 min. Transfer the entire mixture into the polytetrafluoroethylene liner of an autoclave, quickly transfer it to the sealed autoclave, and heat it at 130°C for 24 h. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL of DMF at a speed of 8000 r / min for a single time of 3 minutes, and the supernatant is aspirated with a disposable dropper; then the solid is washed three times with 5-10 mL of deionized water at a speed of 8000 r / min for a single time of 3 minutes; finally, the solid after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for a single time of 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain zinc carboxyl porphyrin polymer (Zn TCPPploy).

[0035] (3) The preparation process of iron carboxyl porphyrin polymer is as follows: Accurately weigh 0.1 mmol, 0.0791 g of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a 50 mL beaker. Add 9 mL of N,N-dimethylformamide (DMF) and sonicate at room temperature for 10 min. Then add 0.1988 g of ferrous chloride tetrahydrate (FeCl2·4H2O). Then, add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 min. Transfer the entire mixture to the polytetrafluoroethylene liner of an autoclave, quickly transfer it to the sealed autoclave, and heat it at 130°C for 24 h. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL of DMF at a speed of 8000 r / min for a single time of 3 minutes, and the supernatant is aspirated with a disposable dropper; then the solid is washed three times with 5-10 mL of deionized water at a speed of 8000 r / min for a single time of 3 minutes; finally, the solid material after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for a single time of 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain iron carboxyl porphyrin polymer (Fe TCPP ploy).

[0036] (4) The preparation process of cobalt carboxyl porphyrin polymer is as follows: Accurately weigh 0.1 mmol, 0.0791 g of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a 50 mL beaker was added, and 9 mL of N,N-dimethylformamide (DMF) was added. The mixture was ultrasonicated at room temperature for 10 min, and then 0.249 g of cobalt acetate tetrahydrate (Co(CH3COO)2·4H2O) was added. Then, 0.5 mL of 6 mol / L glacial acetic acid was added and ultrasonicated at room temperature for another 10 min. The mixture was then transferred to the polytetrafluoroethylene liner of an autoclave, quickly transferred to the autoclave, sealed, and heated at 130°C for 24 h. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL DMF at a speed of 8000 r / min for a single time of 3 minutes, and the supernatant is aspirated with a disposable dropper; then the solid is washed three times with 5-10 mL deionized water at a speed of 8000 r / min for a single time of 3 minutes; finally, the solid material after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for a single time of 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain cobalt carboxyl porphyrin polymer (Co TCPPploy).

[0037] (5) The preparation process of nickel carboxyl porphyrin polymer is as follows: Accurately weigh 0.1 mmol, 0.0791 g of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) in a 50 mL beaker. Add 9 mL of N,N-dimethylformamide (DMF) and sonicate at room temperature for 10 min. Then add 0.237.69 g of nickel chloride hexahydrate (NiCl2·6H2O). Then, add 0.5 mL of 6 mol / L glacial acetic acid and continue sonicating at room temperature for 10 min. Transfer the entire mixture to the polytetrafluoroethylene liner of an autoclave, quickly transfer it to the sealed autoclave, and heat it at 130°C for 24 h. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL of DMF at a speed of 8000 r / min for 3 minutes, and the supernatant is aspirated with a disposable dropper; the solid is then washed three times with 5-10 mL of deionized water at a speed of 8000 r / min for 3 minutes; finally, the solid material after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain nickel-carboxyl porphyrin polymer (Ni TCPP ploy).

[0038] (0) The preparation process of cobalt pyridyl porphyrin polymer is as follows: Accurately weigh 0.0619 g (0.1 mmol) of 5,10,15,20-tetrakis(4-pyridyl)porphyrin (TPyP) into a 50 mL beaker, add 9 mL of N,N-dimethylformamide (DMF), and sonicate at room temperature for 10 min. Then add 0.249 g (1 mmol) of cobalt acetate tetrahydrate, and sonicate at room temperature for 10 min. Transfer the entire mixture into a 20 mL polytetrafluoroethylene-lined container, quickly transfer it to a sealed autoclave, and heat it at 150 °C for 18 h. After the reaction is completed, the high-pressure reactor is cooled to room temperature, and the solution is transferred to a centrifuge tube and centrifuged at 8000 rpm in a centrifuge. The solid matter after centrifugation is first washed three times with 5-10 mL DMF (speed 8000 rpm; single time duration 3 minutes), and then washed three times with deionized water and anhydrous ethanol respectively (repeat the above operation) until the filtrate is clear. After washing, the solid matter obtained by centrifugation is transferred to a clean glass watch dish and placed in a vacuum drying oven at 70 ° C for 12 hours to finally obtain cobalt pyridyl porphyrin polymer (Co TPyPploy).

[0039] Unless otherwise specified, the transition metal carboxyl porphyrin polymers and cobalt pyridyl porphyrin polymers used in Examples 1 to 16 and Comparative Examples 1 to 6 of the present invention were prepared according to the above preparation steps.

[0040] Example 1 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (current 15.8 A, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0041] Comparative Example 1 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. A 26 mL aqueous solution containing 0.2675 g of NH₄Cl and 26 mL of a 30% hydrogen peroxide solution were then added. The reaction was maintained at 35 ± 0.5°C using a constant temperature circulating water system and incubated at 800 rpm for 12 hours. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0042] Comparative Example 2 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of distilled water, and 26 mL of 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0043] Comparative Example 3 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. 26 mL of distilled water and 26 mL of 30% hydrogen peroxide solution were then added, sequentially. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 hours. After terminating the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0044] Example 2 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 20 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0045] Example 3 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 25 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0046] Example 4 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 30 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0047] Example 5 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (current 15.8 A, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 40 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0048] Example 6 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.7455 g of (NH₄)₃PO₄, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0049] Comparative Example 4 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2922 g of NaCl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0050] Example 7 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 43.33 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 8.67 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0051] Example 8 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 34.7 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 17.3 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0052] Comparative Example 5 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy) and 52 mL of an aqueous solution containing 0.2675 g of NH₄Cl were added sequentially. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0053] Example 9 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 0.500 ± 0.005 g). Under irradiation with a 300 W xenon lamp (current 15.8 A, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0054] Example 10 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 0.250 ± 0.005 g). Under irradiation with a 300 W xenon lamp (current 15.8 A, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0055] Example 11 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of cobalt pyridylporphyrin polymer (CoTPyP ploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0056] Example 12 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 0.500 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of cobalt pyridylporphyrin polymer (CoTPyPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0057] Example 13 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 0.250 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of cobalt pyridylporphyrin polymer (CoTPyPploy), 26 mL of aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0058] Example 14 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of zinc-carboxylporphyrin polymer (ZnTCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0059] Example 15 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of iron-carboxyl porphyrin polymer (FeTCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH4Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed and the final solution was collected.

[0060] Example 16 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of nickel-carboxylporphyrin polymer (Ni TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system. The reaction was incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0061] Comparative Example 6 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) was added, followed by a 26 mL aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution. The reaction was maintained at 35 ± 0.5°C using a constant temperature circulating water system and incubated at 800 rpm for 12 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0062] Example 17 Copper-containing waste electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the waste electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 24 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0063] The preparation method of the manganese carboxyl porphyrin polymer used in this example is as follows: 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) was accurately weighed (0.1 mmol, 0.0791 g) in a 50 mL beaker, 9 mL of N,N-dimethylformamide (DMF) was added, and ultrasonication was performed at room temperature for 10 minutes. Then, 0.245 g of manganese acetate tetrahydrate Mn(CH3COO)2·4H2O was added, and then 0.5 mL of 6 mol / L glacial acetic acid was added and ultrasonication was continued at room temperature for 10 minutes. The entire mixture was then transferred to the polytetrafluoroethylene liner of an autoclave, quickly transferred to the autoclave, sealed, and heated at 140°C for 22 hours. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL of DMF at a speed of 8000 r / min for a single time of 3 minutes, and the supernatant is aspirated with a disposable dropper; then the solid is washed three times with 5-10 mL of deionized water at a speed of 8000 r / min for a single time of 3 minutes, and finally the solid material after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for a single time of 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain manganese carboxyl porphyrin polymer (Mn TCPP ploy).

[0064] Example 18 Copper-containing scrap electronic printed circuit boards were cut into 1.0 cm × 1.0 cm slices (total mass 1.000 ± 0.005 g). Under irradiation with a 300 W xenon lamp (15.8 A current, spectral wavelength range 400-800 nm), the scrap electronic printed circuit board slices were placed in a 100 mL sealed glass reactor. Then, 20.0 mg of manganese carboxyl porphyrin polymer (Mn TCPPploy), 26 mL of an aqueous solution containing 0.2675 g of NH₄Cl, and 26 mL of a 30% hydrogen peroxide solution were added in sequence. The system temperature was maintained at 35 ± 0.5°C using a constant temperature circulating water system, and the reaction was carried out at 800 rpm for 20 h. After termination of the reaction, the unreacted printed circuit board was removed, and the final solution was collected.

[0065] The preparation method of the manganese carboxyl porphyrin polymer used in this example is as follows: 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) was accurately weighed (0.1 mmol, 0.0791 g) in a 50 mL beaker, 9 mL of N,N-dimethylformamide (DMF) was added and, depending on the dissolution, ultrasonicated at room temperature for 10 minutes. Then, 0.245 g of manganese acetate tetrahydrate Mn(CH3COO)2·4H2O was added, followed by 0.5 mL of 6 mol / L glacial acetic acid and continued ultrasonication at room temperature for 10 minutes. The whole mixture was then transferred to the polytetrafluoroethylene liner of an autoclave, quickly transferred to the autoclave, sealed, and heated at 150°C for 20 hours. After the reaction is completed, the solution is cooled to room temperature and transferred to a centrifuge tube and centrifuged at 8000 r / min in a centrifuge. The solid material after centrifugation is first washed three times with 5-10 mL DMF at a speed of 8000 r / min for a single time of 3 minutes, and the supernatant is aspirated with a disposable dropper; then the solid is washed three times with 5-10 mL deionized water at a speed of 8000 r / min for a single time of 3 minutes, and finally the solid material after centrifugation is washed three times with 5-10 mL of anhydrous ethanol at a speed of 8000 r / min for a single time of 3 minutes until the filtrate is clear and transparent. After washing, the solid material obtained by centrifugation is transferred to a clean watch glass and placed in a vacuum drying oven with the temperature set at 70°C and the drying time for 12 hours to finally obtain manganese carboxyl porphyrin polymer (Mn TCPP ploy).

[0066] 2 mol / L HCl was added to the final reaction solution, and after filtering through a 0.22 μm filter membrane, the copper content was determined by atomic absorption spectroscopy. Simultaneously, 1.0 cm × 1.0 cm slices of unreacted original electronic printed circuit boards were dissolved with 2.0 mol / L HCl. The total copper content was determined using the same method, and the dissolution efficiency was calculated according to the following formula. Each experiment was repeated three times and the average value was used to ensure data reliability: E Cu is the photocatalytic copper dissolution rate (%), C a is the Cu content in the solution (mg / L), and C0 is the total Cu content in the waste copper-clad circuit board material (mg / L).

[0067] (1) Effect of catalyst on the dissolution of copper in aqueous system at room temperature Figure 1The photocatalytic dissolution of copper from printed circuit boards in Example 1 and Comparative Examples 1-3, with and without a catalyst, is shown. The effects of the presence and absence of coordinating ions in the aqueous system on copper recovery are also compared. The results demonstrate the crucial role of photocatalysts and coordinating ions in copper dissolution and recovery. The introduction of a metallocarboxylporphyrin polymer (Mn TCPP ploy) as a photocatalyst significantly improves the copper dissolution rate. Control experiments demonstrate that the synergistic introduction of the photocatalyst and NH₄Cl increases the dissolution rate to 74.71%, an increase of approximately 73% compared to the single oxidant system. Compared to the copper dissolution rate in pure water, the addition of the catalyst and coordinating ions significantly enhances copper recovery, demonstrating the research significance of this system for copper recovery.

[0068] (2) Effect of temperature on photocatalytic dissolution of copper In Examples 1 to 5, the catalyst content was 20 mg, the concentration of the aqueous solution of the ammonium salt was 0.1 mol / L, the ratio of the total volume of the copper-containing electronic waste to the aqueous solution of the ammonium salt and the hydrogen peroxide was 1 g:50 mL, and the mass concentration of the hydrogen peroxide in the aqueous solution of the ammonium salt was 15%. The effect of temperature on the dissolution of copper was studied. Figure 2 As shown, temperature significantly influences the photocatalytic dissolution reaction. At 20°C to 40°C, the efficiency of copper dissolution in electronic waste samples using a metal carboxyl porphyrin polymer (Mn TCPP ploy) as a photocatalyst increases with increasing temperature, demonstrating that elevated temperature promotes the overall reaction. The optimal solubility of this system, 95.48%, is achieved at 40°C. Based on temperature control requirements, the present invention selected 35°C for subsequent treatment.

[0069] (3) Effect of inorganic salts on photocatalytic dissolution of copper The dissolution efficiency of copper is closely related to the inorganic salt in the photocatalytic system. After selecting ions with strong coordination effects with copper ions and combining them, different inorganic salt solutions were prepared. In Comparative Example 4, Example 4 and Example 6, the amount of catalyst added was kept at 20 mg, the concentration of the aqueous solution of ammonium salt was 0.1 mol / L, the ratio of the total volume of copper-containing electronic waste to the aqueous solution of ammonium salt and hydrogen peroxide was 1 g:50 mL, the mass concentration of hydrogen peroxide in the aqueous solution of ammonium salt was 15%, and the temperature was 35 ° C. The experiment was repeated in different systems of NaCl, NH4Cl, and (NH4)3PO4, and the results are as follows. Figure 3 As shown in the figure, when NaCl is used, the dissolution of copper cannot be promoted, and the final dissolution rate is only 1.6%. Comparing the results of NH4Cl and (NH4)3PO4, it can be seen that when NH4 +When the temperature is 5000 °C, the dissolution efficiency of copper is 74.71% and 64.28% respectively. Under the synergistic effect of NH4⁺ and Cl⁻ ions, the dissolution rate of copper is increased to 74.71% at 35°C. Compared with other halogen ammonium salts such as ammonium bromide, the complex ion produced by ammonium chloride and copper is more easily oxidized to CuO and Cu(OH)2 under the preparation conditions of the present invention, while the complex ion [CuBr4] produced by bromide ion and copper is more easily oxidized to CuO and Cu(OH)2 under the preparation conditions of the present invention. 2- Due to its higher stability, it is difficult to finally convert into Cu 2+ , Cu 2+ It is more convenient to subsequently reduce the recovered liquid to pure copper for utilization and recycling.

[0070] (4) Effect of hydrogen peroxide concentration on photocatalytic dissolution of copper H2O2 can effectively oxidize copper in solid waste and further promote the dissolution of copper. In Example 1, Example 7 to Example 8 and Comparative Example 5, the amount of catalyst added was kept at 20 mg, the concentration of the aqueous solution of ammonium salt was kept at 0.1 mol / L, the ratio of the total volume of the copper-containing electronic waste to the aqueous solution of ammonium salt and hydrogen peroxide was kept at 1 g:50 mL, and the temperature was kept at 35°C. The mass concentration of hydrogen peroxide in the ammonium salt was changed from Figure 4 As can be seen, when the H2O2 concentration is 5%, the copper dissolution rate reaches over 95%. As the H2O2 concentration increases, the copper dissolution rate gradually decreases. This demonstrates that the higher the H2O2 concentration, the more beneficial the oxidant is. When the H2O2 concentration is too high, the large amount of oxygen bubbles generated by the decomposition of the H2O2 adsorb on the surface of the printed circuit board, hindering contact between the copper on the printed circuit board and the solution, thereby reducing the copper dissolution efficiency.

[0071] (5) Effect of solid-liquid ratio on photocatalytic dissolution of copper In Examples 1, 9, and 10, the amount of catalyst added was kept at 20 mg, the concentration of the aqueous solution of the ammonium salt was kept at 0.1 mol / L, the mass concentration of hydrogen peroxide in the aqueous solution of the ammonium salt was kept at 15%, and the temperature was kept at 35°C. The ratio of the mass of the copper-containing waste electronic printed board sample to the volume of the solution, i.e., the solid-liquid ratio, was changed to study the change in the copper dissolution rate in the system. Figure 5 As shown in the results, the copper dissolution rate increases when the solid-liquid ratio increases from 1g:50mL to 1g:200mL. When the solid-liquid ratio increases from 1g:50mL to 1g:100mL, the copper recovery rate increases from 74.71% to 80.98%. When the solid-liquid ratio is 1g:200mL, the copper recovery rate further increases to 83.24%. This shows that as the solid-liquid ratio decreases, the copper dissolution rate increases slightly.

[0072] In Examples 11 to 13, cobalt pyridylporphyrin polymer was used as a catalyst, the catalyst addition amount was kept at 20 mg, the concentration of the aqueous solution of ammonium salt was 0.1 mol / L, the mass concentration of hydrogen peroxide in the aqueous solution of ammonium salt was 15%, and the temperature was 35°C. The ratio of the mass of the copper-containing waste electronic printed circuit board sample to the solution volume was changed to study the change in the copper dissolution rate in the system, as shown in FIG. Figure 6 As shown in the figure, at a solid-to-liquid ratio of 1:50, its copper dissolution efficiency is 68.35%, which is lower than the photocatalytic dissolution efficiency of manganese carboxyl porphyrin polymer for copper at the same solid-to-liquid ratio. The results show that manganese carboxyl porphyrin polymer is very important in the photocatalytic dissolution of copper in printed circuit boards. Both the peripheral substituents and the central metal ion of the porphyrin polymer can significantly affect the conduction band position of the photocatalyst. The conduction band potential of manganese carboxyl porphyrin polymer is lower, significantly lower than the potential of O2 / ·O2⁻, making it more likely to generate superoxide anion radicals during the photocatalytic process, resulting in higher photocatalytic activity.

[0073] from Figure 7 The content of different metals in the original waste electronic printed circuit board is shown in Figure 1. Example 1, Example 11, Example 14 to Example 16 and the comparative example studied the solubility rate of different transition metal porphyrin polymers for copper. Figure 8 It can be seen that the manganese carboxyl porphyrin polymer recovered almost all of the copper, with a selectivity of up to 99%. Compared with the porphyrin monomer, the manganese carboxyl porphyrin polymer has a specific surface area of ​​43.499 m 2 / g, is a mesoporous material, which exposes more active sites during the photocatalytic dissolution process and promotes the photocatalytic reaction to a greater extent; and due to the multiple valence variations of Mn, it can better promote the transfer of photocatalytic electrons, which is beneficial to the generation of reactive oxygen species; and it has stronger thermal stability and is more stable in water; and the above photocatalytic process can stimulate it to produce photogenerated electrons and photogenerated holes under visible light irradiation, thereby promoting the oxidation and dissolution of copper.

[0074] Figure 9 The color photographs of the solution before and after the photocatalytic dissolution of copper in the printed circuit board using manganese carboxyl porphyrin polymer in Example 1 are shown. Figure 9 In Figure a, the dark purple color is the color of the solution just after adding the manganese carboxyl porphyrin polymer; Figure 9 In Figure b, blue is the color of the solution after 12 hours of photocatalysis of manganese carboxyl porphyrin polymer. After the photocatalytic reaction, the solution turns obviously blue, which is the characteristic color of copper ions.

[0075] After using it 5 times in a very stable manner according to the operating method of Example 1, Figure 10 As can be seen from (a), the catalyst still maintains a high dissolution efficiency, and the decline in efficiency is due to repeated centrifugal loss of the catalyst. Figure 10As can be seen from (b) in the figure, there is no change in the surface groups of the catalyst before and after the catalytic dissolution reaction, indicating that it is very stable.

[0076] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0077] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for photocatalytic dissolution of copper in electronic waste, characterized in that: The following steps are involved: A transition metal porphyrin polymer, an aqueous solution of an ammonium salt, and hydrogen peroxide are uniformly mixed to obtain a mixed solution; the transition metal porphyrin polymer is obtained by hydrothermal reaction at 130°C to 150°C with 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin, a transition metal source, and glacial acetic acid using N'N-dimethylformamide as a solvent; Copper-containing electronic waste is added to the mixed solution. Under the action of visible light, the transition metal porphyrin polymer acts as a photocatalyst, and copper and ammonium salt are coordinated to dissolve the copper in the electronic waste at 20℃~40℃ and normal pressure.

2. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that: The ammonium salt is ammonium chloride or ammonium phosphate.

3. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that: The transition metal porphyrin polymer is a transition metal carboxyl porphyrin polymer or a transition metal pyridyl porphyrin polymer, and the transition metal is manganese, zinc, iron, cobalt or nickel.

4. The method for photocatalytically dissolving copper in electronic waste according to claim 1, characterized in that: The mass ratio of the transition metal porphyrin polymer to the copper-containing electronic waste is 20 mg: 0.25 g to 1 g.

5. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that: The total volume of the copper-containing electronic waste, the aqueous solution of ammonium salt and hydrogen peroxide is 1g:50mL~200mL, and the concentration of the aqueous solution of ammonium salt is 0.1mol / L.

6. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that: The mass concentration of hydrogen peroxide in the aqueous solution of ammonium salt is 5%~15%.

7. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that: The dissolving temperature is 35℃~40℃.

8. The method for photocatalytically dissolving copper in electronic waste according to claim 1, characterized in that: The dissolution time is 12h~24h.

9. The method for photocatalytic dissolution of copper in electronic waste according to claim 1, characterized in that: When preparing the transition metal porphyrin polymer, the hydrothermal reaction time is 20h~24h.

10. The method for photocatalytically dissolving copper in electronic waste according to claim 1, characterized in that: Copper-containing electronic waste refers to electronic printed circuit boards or copper-clad laminates containing copper.

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