A method for preparing octahedral cuprous oxide by using PCB etching waste liquid

Abstract

The application belongs to the technical field of cuprous oxide and provides a method for preparing octahedral cuprous oxide by using PCB etching waste liquid, which comprises the following steps: mixing alkaline PCB etching waste liquid and acidic PCB etching waste liquid until a set pH value is reached, and cooling the mixture to a set temperature to obtain a mixed solution; filtering the mixed solution; adding a set amount of hydroxylamine hydrochloride solution to the filtered mixed solution, stirring at a set temperature for a set time, and obtaining a mixed solution mixed with part of precipitates; stirring and heating the mixed solution mixed with part of precipitates to a set temperature, continuously blowing air into the solution, and obtaining a reacted mixed solution; and performing ethanol / water washing centrifugation on the reacted mixed solution, and performing vacuum drying to obtain octahedral cuprous oxide. The preparation method has low cost, and there are no toxic substances to the human body and no new three wastes generated in the process.

Description

Technical Field

[0001] This invention belongs to the field of cuprous oxide technology, and specifically relates to a method for preparing octahedral cuprous oxide using PCB etching waste liquid. Background Technology

[0002] In recent years, with the rapid development of microelectronics technology, PCBs have become increasingly widely used due to their special functions and are poised to become a future trend in printed circuit board manufacturing. In 2022, the global PCB production value reached US$81.741 billion, with China accounting for approximately 60%, making it the world's largest PCB production base. The PCB production process generates a large amount of copper-containing etching wastewater, and current disposal methods cause secondary pollution to the environment and result in low added value for the products. Therefore, developing a process for recycling and preparing new copper-based materials from PCB etching wastewater has significant economic and environmental benefits.

[0003] Cuprous oxide is an important antifouling material for ships. It releases cuprous ions, which can effectively inhibit the attachment and growth of microorganisms and reduce biofouling on the ship's surface. Among them, octahedral cuprous oxide has higher activity, faster copper ion release rate, and better antifouling and bactericidal performance than cubic and spherical cuprous oxide, and is therefore more suitable for the field of ship antifouling.

[0004] Current reports on octahedral cuprous oxide mostly use pure divalent copper salts such as copper nitrate, copper acetate, or copper sulfate as the copper source, hydrazine hydrate, sodium citrate, and ascorbic acid as reducing agents, and PVP and PEG as surfactants. These methods have drawbacks such as high raw material costs or the strong reducing power of the reducing agents leading to the reduction of some copper salts to elemental copper. A very small number of studies use acidic copper-containing etching waste liquid to produce octahedral cuprous oxide, but this method currently requires the addition of PEG surfactant for surface reduction before the addition of a monohydric aldehyde reducing agent for reaction. However, monohydric aldehyde reducing agents are toxic to humans, and the addition of PEG surfactant increases production costs. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing octahedral cuprous oxide using PCB etching waste liquid, aiming to solve at least one technical problem in the background art.

[0006] This invention is implemented as follows: a method for preparing octahedral cuprous oxide using PCB etching waste liquid, comprising the following steps: Step 1: Mix the alkaline PCB etching waste liquid and the acidic PCB etching waste liquid until the pH value of the mixed liquid reaches the set pH value, and then cool it to the first set temperature to obtain a mixed solution. Step 2: Filter the mixed solution to remove solid impurities and suspended matter. Step 3: Add a set amount of hydroxylamine hydrochloride solution to the filtered mixed solution, and stir at the first set temperature for a first set time to obtain a mixed solution containing some precipitate; Step 4: Stir and heat the mixed solution containing some precipitate to the second set temperature, and continuously bubble air into it for a period of time to generate a brick-red precipitate, wherein the air bubbling time is the second set time. Step 5: The brick-red precipitate is washed with ethanol / water, centrifuged, and then vacuum dried to obtain octahedral cuprous oxide.

[0007] In a preferred embodiment, in step one, the pH value is set to 3.5-4.5. In a preferred embodiment, in step one, the copper ion content in the mixed solution is 10%. In a preferred embodiment, in step three, the concentration of the hydroxylamine hydrochloride solution is 2 mol / L, and the volume ratio of the mixed solution to the hydroxylamine hydrochloride solution is 1:1 to 1.5. In a preferred technical solution, in step three, the first set time is 40 minutes. In a preferred embodiment, in step four, the stirring rate of the mixed solution containing some precipitate is 200 rpm, the second set temperature is 40-60 ℃, and the second set time is 5-10 min. In a preferred embodiment, step one, which involves mixing the alkaline PCB etching waste liquid and the acidic PCB etching waste liquid until the pH value of the mixed liquid reaches a set pH value, includes: By adding acidic PCB etching waste liquid to alkaline PCB etching waste liquid, the pH value of the mixed liquid is adjusted until the set pH value is reached. In a preferred embodiment, in step five, the vacuum drying conditions are vacuum drying at a temperature of 50-70°C for 8-12 hours. In a preferred embodiment, step five, which involves washing the brick-red precipitate with ethanol / water and centrifuging, includes: The brick-red precipitate was washed and centrifuged with 0.5-2 L of ethanol and water, respectively. In another aspect, the present invention also proposes an octahedral cuprous oxide, which is prepared by the method described in any of the above-mentioned methods for preparing octahedral cuprous oxide using PCB etching waste liquid.

[0008] Compared with existing technologies: By using hydroxylamine hydrochloride as a reducing agent, the amino group in hydroxylamine hydrochloride will act as a complexing agent with the organic phase and chloride ions in the etching solution. No additional surfactants or complexing agents are needed to obtain octahedral cuprous oxide, which greatly reduces costs. Furthermore, no toxic substances or new wastes are generated during the process. Attached Figure Description

[0009] Figure 1 This is a scanning electron microscope (SEM) image of octahedral cuprous oxide prepared in one embodiment of the present invention.

[0010] Figure 2 This is an X-ray diffraction (XRD) pattern of octahedral cuprous oxide prepared in one embodiment of the present invention. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0012] Current reports on octahedral cuprous oxide mostly use pure divalent copper salts such as copper nitrate, copper acetate, or copper sulfate as the copper source, hydrazine hydrate, sodium citrate, and ascorbic acid as reducing agents, and PVP and PEG as surfactants. These methods suffer from drawbacks such as high raw material costs or the strong reducing power of the reducing agents leading to the reduction of some copper salts to elemental copper. A very small number of studies use acidic copper-containing etching waste liquid to prepare octahedral cuprous oxide, but this method currently requires the addition of PEG surfactant for surface reduction before the addition of a monohydric aldehyde reducing agent for further reaction. However, monohydric aldehyde reducing agents are toxic to humans, and the addition of PEG surfactant increases production costs. To solve these existing technical problems, this invention employs a completely different preparation process to prepare nanoporous copper oxide materials. The specific technical solution is as follows: A method for preparing octahedral cuprous oxide using PCB etching waste liquid according to an embodiment of the present invention includes the following steps: Step 1: Mix the alkaline PCB etching waste liquid and the acidic PCB etching waste liquid until the pH value of the mixed liquid reaches the set pH value, and then cool it to the first set temperature to obtain a mixed solution. The first set temperature can be room temperature. Step 2: Filter the mixed solution to remove solid impurities and suspended matter. Step 3: Add a set amount of hydroxylamine hydrochloride solution to the filtered mixed solution, and stir for a set time at the first set temperature to allow the hydroxylamine hydrochloride solution to react fully with the mixed solution, thereby obtaining a mixed solution containing some precipitate. The second set temperature can be room temperature. Step 4: Stir and heat the mixed solution containing some precipitate to the second set temperature, and continuously bubble air into it for a period of time to generate a brick-red precipitate. The bubble air duration is the second set time. The purpose of bubbling air is to accelerate the hydrolysis reaction of the precipitate. Step 5: The brick-red precipitate was washed with ethanol / water, centrifuged, and then vacuum dried to obtain octahedral cuprous oxide. The octahedral cuprous oxide was a particulate material. A scanning electron microscope (SEM) image of the prepared octahedral cuprous oxide is shown below. Figure 1 The X-ray diffraction (XRD) pattern shown is as follows. Figure 2 As shown.

[0013] In specific implementation, the step of mixing alkaline PCB etching waste liquid and acidic PCB etching waste liquid until the pH value of the mixed liquid reaches the set pH value includes: adding acidic PCB etching waste liquid to the alkaline PCB etching waste liquid to adjust the pH value of the mixed liquid to the set pH value. Of course, in some optional embodiments, alkaline PCB etching waste liquid can also be added to the acidic PCB etching waste liquid, or both acidic and alkaline PCB etching waste liquids can be added to the container simultaneously for mixing, as long as the pH value of the final mixed liquid after mixing the acidic and alkaline PCB etching waste liquids reaches the set pH value.

[0014] In other words, the specific process of preparing octahedral cuprous oxide using PCB etching waste liquid in the embodiments of the present invention is roughly as follows: First, acidic PCB etching waste liquid is added to alkaline PCB etching waste liquid to adjust its pH, and after cooling to room temperature, solution A is obtained; then solution A is filtered to remove solid impurities and suspended matter to obtain solution B; a certain amount of hydroxylamine hydrochloride solution is added to solution B, and stirred at room temperature for a certain time to obtain a mixed solution C containing some precipitate; in step four, the mixed solution C after the reaction in step three is stirred and heated to a certain temperature and air is continuously bubbled in for a certain time; in step five, the mixed solution after the reaction in step four is washed with ethanol / water, centrifuged, and vacuum dried to obtain octahedral cuprous oxide.

[0015] In some preferred embodiments, in step one, the set pH value is 3.5-4.5, for example, pH value can be 4 or 4.2, etc.; in step one, the copper ion content in the mixed solution is 10%. In step three, the concentration of hydroxylamine hydrochloride solution is 2 mol / L, and the mixing volume ratio of the mixed solution to the hydroxylamine hydrochloride solution is 1:1 to 1.5, for example, the mixing volume ratio of the mixed solution to the hydroxylamine hydrochloride solution can be 1:1 or 1:1.2, etc. In step three, the first set time is 40 min, that is, after the filtered mixed solution is mixed with the hydroxylamine hydrochloride solution, it is stirred at room temperature for 40 min. In step four, the stirring rate of the mixed solution containing some precipitate is 200 rpm, the second set temperature is 40-60 °C, and the second set time is 5-10 min. Specifically, the mixed solution containing some precipitate can be stirred and heated to 40-60 °C (e.g., 45 or 50 °C) at a stirring rate of 200 rpm, with air continuously bubbled in for 5-10 min during the heating process. In step five, the vacuum drying conditions are vacuum drying at 50-70 °C for 8-12 hours, for example, vacuum drying at 55 or 60 °C for 10 or 11 hours.

[0016] Furthermore, in step five, the step of washing and centrifuging the brick-red precipitate with ethanol / water includes: The brick-red precipitate was washed and centrifuged with 0.5-2 L of ethanol and water, respectively. Specifically, the mixture could be washed and centrifuged with 1 L of ethanol first, followed by 1 L of water, and then centrifuged again. Alternatively, the mixture could be washed and centrifuged with 1 L of water first, followed by 1 L of ethanol. In some optional embodiments, ethanol or water alone could be used to wash and centrifuge the mixture.

[0017] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0018] Example 1 A method for preparing octahedral cuprous oxide using PCB etching waste liquid includes the following steps: Step 1: First, take 500 mL of alkaline PCB etching waste liquid. Then, under the condition of real-time pH measurement with a pH meter, slowly add acidic PCB etching waste liquid to the alkaline PCB etching waste liquid until the pH reaches 3.5. After cooling to room temperature, solution A is obtained, in which the copper ion content is approximately 10%. Step 2: Filter solution A to remove solid impurities and suspended matter to obtain solution B; Step 3: Add an equal volume of hydroxylamine hydrochloride solution (2 mol / L) to solution B and stir at room temperature for 40 min to obtain a mixed solution C containing some precipitate; Step 4: Heat the mixed solution C containing some precipitate to 50°C while stirring at 200 rpm and continuously bubble air in for 10 min; Step 5: After washing and centrifuging the mixed solution from step 4 with 1L of ethanol and water respectively, the solution is then dried under vacuum at 60℃ for 10 hours to obtain octahedral cuprous oxide particles.

[0019] Example 2 A method for preparing octahedral cuprous oxide using PCB etching waste liquid includes the following steps: Step 1: First, take 500 mL of alkaline PCB etching waste liquid. Then, under the condition of real-time pH measurement, slowly add acidic PCB etching waste liquid to the alkaline PCB etching waste liquid until the pH reaches 4.0. After cooling to room temperature, solution A is obtained, in which the copper ion content is approximately 10%. Step 2: Filter solution A to remove solid impurities and suspended matter to obtain solution B; Step 3: Add 1.2 times the volume of hydroxylamine hydrochloride solution (2 mol / L) to solution B, and stir at room temperature for 40 min to obtain a mixed solution C containing some precipitate; Step 4: Heat the mixed solution C containing some precipitate to 50°C while stirring at 200 rpm and continuously bubble air in for 10 min; Step 5: After washing and centrifuging the mixed solution from step 4 with 1L of ethanol and water respectively, the solution is then dried under vacuum at 60℃ for 10 hours to obtain octahedral cuprous oxide particles.

[0020] Example 3 A method for preparing octahedral cuprous oxide using PCB etching waste liquid includes the following steps: Step 1: First, take 500 mL of alkaline PCB etching waste liquid. Then, under the condition of real-time pH measurement with a pH meter, slowly add acidic PCB etching waste liquid to the alkaline PCB etching waste liquid until the pH reaches 4.5. After cooling to room temperature, solution A is obtained, in which the copper ion content is approximately 10%. Step 2: Filter solution A to remove solid impurities and suspended matter to obtain solution B; Step 3: Add 1.5 times the volume of hydroxylamine hydrochloride solution (2 mol / L) to solution B, and stir at room temperature for 40 min to obtain a mixed solution C containing some precipitate; Step 4: Heat the mixed solution C containing some precipitate to 50°C while stirring at 200 rpm and continuously bubble air in for 10 min; Step 5: After washing and centrifuging the mixed solution from step 4 with 1L of ethanol and water respectively, the solution is then dried under vacuum at 60℃ for 10 hours to obtain octahedral cuprous oxide particles.

[0021] Compared with existing technologies, the beneficial effects of this invention are reflected in: 1. In this embodiment of the invention, hydroxylamine hydrochloride is used as a reducing agent to first reduce the divalent copper ions in the etching waste liquid to cuprous chloride or cuprous chloride acid, and then perform hydrolysis to prepare cuprous oxide; 2. The hydroxylamine hydrochloride reducing agent used in the embodiments of the present invention has moderate reducing power and will not over-reduce divalent copper ions to elemental copper. 3. In this embodiment of the invention, the organic phase, chloride ions and amino groups in hydroxylamine hydrochloride in the etching solution are used directly as complexing agents, without the addition of other surfactants or complexing agents, to obtain cuprous oxide with an octahedral morphology.

[0022] 4. No new waste is generated during the preparation of octahedral cuprous oxide products in the embodiments of the present invention.

[0023] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing octahedral cuprous oxide using PCB etching waste liquid, characterized in that, Includes the following steps: Step 1: Mix the alkaline PCB etching waste liquid and the acidic PCB etching waste liquid until the pH value of the mixed liquid reaches the set pH value, and then cool it to room temperature to obtain a mixed solution. The set pH value is 3.5-4.5, and the copper ion content in the mixed solution is 10%. Step 2: Filter the mixed solution to remove solid impurities and suspended matter. Step 3: Add a set amount of hydroxylamine hydrochloride solution to the filtered mixed solution and stir at room temperature for a first set time to obtain a mixed solution containing some precipitate. The volume ratio of the mixed solution to the hydroxylamine hydrochloride solution is 1:1 to 1.5, the concentration of the hydroxylamine hydrochloride solution is 2 mol / L, and the first set time is 40 min. Step 4: Stir and heat the mixed solution containing some precipitate to the second set temperature, and continuously bubble air for a period of time to generate brick red precipitate. The air bubbling time is the second set time. The second set temperature is 40℃-60℃ and the second set time is 5-10min. Step 5: The brick-red precipitate is washed with ethanol / water, centrifuged, and then vacuum dried to obtain octahedral cuprous oxide.

2. The method of claim 1, wherein the octahedral cuprous oxide is prepared using the PCB etching waste liquid. In step four, the stirring rate of the mixed solution containing some precipitate is 200 rpm. 3.The method for preparing octahedral cuprous oxide using PCB etching waste liquid according to claim 1, characterized in that, In step one, the process of mixing alkaline PCB etching waste liquid and acidic PCB etching waste liquid until the pH value of the mixed liquid reaches the set pH value includes: By adding acidic PCB etching waste liquid to alkaline PCB etching waste liquid, the pH value of the mixed liquid is adjusted until the set pH value is reached.

4. The method for preparing octahedral cuprous oxide using PCB etching waste liquid according to claim 1, characterized in that, In step five, the vacuum drying conditions are vacuum drying at a temperature of 50-70℃ for 8-12 hours.

5. The method for preparing octahedral cuprous oxide using PCB etching waste liquid according to claim 1 or 4, characterized in that, In step five, the step of washing and centrifuging the brick-red precipitate with ethanol / water includes: The brick-red precipitate was washed and centrifuged with 0.5-2 L of ethanol and water, respectively.

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