A method for preparing an adsorbent by using waste circuit board vacuum pyrolysis residue

Abstract

The present application belongs to the technical field of waste recycling, and discloses a method for preparing adsorbent from waste printed circuit board vacuum pyrolysis residue. The method comprises the following steps: crushing, sieving, washing and drying the waste printed circuit board vacuum pyrolysis residue to obtain an adsorbent precursor; mixing the adsorbent precursor with an acid solution to perform impregnation treatment and obtain a mixed solution; performing ultrasonic treatment on the mixed solution; filtering the mixed solution after ultrasonic treatment, collecting the solid, and then washing and drying the solid to obtain the adsorbent. The adsorbent is prepared by acid impregnation-ultrasonic treatment on the waste printed circuit board vacuum pyrolysis residue, and has the characteristics of simple and easy process, low manufacturing cost, high resource utilization rate and environmental friendliness, etc. The method can well solve the problems of traditional landfill treatment of vacuum pyrolysis residue and occupation of land resources, etc. The prepared adsorbent can be well applied to the treatment and disposal of printing and dyeing wastewater, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of waste recycling technology, and specifically relates to a method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards. Background Technology

[0002] Waste circuit boards contain abundant metals such as gold, silver, and copper, and are thus often referred to as "urban mines." Due to their high metal content and economic value, most research focuses on the efficient recovery of these metal components, and current metal recycling technologies are quite mature. However, the remaining non-metallic components (resin components) are mostly disposed of through landfill or incineration, leading to resource waste and potential environmental problems.

[0003] Regarding the regeneration of waste circuit board resin powder into adsorbents, scholars both domestically and internationally have conducted considerable research. Zhao Jifeng et al. (2019) used non-metallic components from waste circuit boards as a carbon source to prepare magnetic porous carbon materials through a two-step activation-magnetization method. Lü Wei et al. (2014) used a carbonization-KOH impregnation-activation method to prepare activated carbon from waste computer circuit boards. Yang Ertao et al. (2011) used non-metallic separations from waste printed circuit boards as precursors to prepare granular activated carbon through pyrolysis, molding, carbonization, and steam activation. Patent document CN107867687A prepared activated carbon from waste printed circuit boards by directly pulverizing the non-metallic parts into powder before activation. However, due to the presence of impurities such as glass fibers in the non-metallic powder from waste circuit boards, the preparation efficiency, yield, and quality of the activated carbon were low. These technologies still have the following problems: (1) The preparation of adsorbents requires secondary high-temperature pyrolysis or activation, which results in high energy consumption; (2) Directly preparing adsorbents from waste circuit board resin powder through carbonization-secondary activation will reduce the recycling of organic components in waste circuit board resin powder and cause resource waste.

[0004] Therefore, it is essential to develop a method for preparing adsorbents that can reduce energy consumption without affecting the recycling of organic components in waste circuit board resin powder. Summary of the Invention

[0005] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention provides a method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards. This method is characterized by its simple operation, energy saving and consumption reduction, improved production efficiency, reduced production costs, and does not affect the recycling of organic components in the resin powder from waste circuit boards.

[0006] The first aspect of this invention provides a method for preparing an adsorbent using vacuum pyrolysis residue from waste circuit boards, comprising the following steps:

[0007] Waste circuit board vacuum pyrolysis residue is crushed, sieved, washed and dried to obtain adsorbent precursor;

[0008] The adsorbent precursor is mixed with an acid solution and impregnated to obtain a mixture.

[0009] The mixture is subjected to ultrasonic treatment;

[0010] The mixture after ultrasonic treatment is filtered to collect the solid, which is then washed with water and dried to obtain the adsorbent.

[0011] The method provided by this invention uses vacuum pyrolysis slag from waste circuit boards as raw material. The waste circuit board vacuum pyrolysis slag is mainly composed of pyrolysis carbon and glass fiber. Pyrolysis carbon adsorbent material is prepared by acid impregnation and ultrasonic treatment. First, it can reduce the traditional secondary pyrolysis or activation operation and save energy consumption. Second, the acid solution corrodes the pyrolysis carbon to form adsorption pores of various sizes, which can remove residual metals in non-metallic components. Third, the high-frequency ultrasonic vibration is used to expand the adsorption pore size and improve the adsorption performance.

[0012] According to some embodiments of the present invention, the waste circuit board vacuum pyrolysis residue is obtained by vacuum pyrolysis of waste circuit board resin powder at 400-550°C. After vacuum pyrolysis and carbonization, the non-metallic components of the waste circuit board are converted into carbon-based materials, while the properties of the glass fiber remain essentially unchanged, facilitating subsequent separation and removal.

[0013] According to some embodiments of the present invention, the sieving is performed through a 120-200 mesh sieve. Sieving can remove glass fibers from the vacuum pyrolysis residue of waste circuit boards.

[0014] According to some embodiments of the present invention, the drying temperature is ≥100°C. Further, the drying temperature is 100-110°C.

[0015] According to some embodiments of the present invention, the acid solution includes at least one of hydrochloric acid, nitric acid, phosphoric acid, acetic acid, and citric acid.

[0016] According to some embodiments of the present invention, the concentration of the acid solution is 0.1-10 mol / L. Further, the concentration of the acid solution is 0.1-5 mol / L. Even further, the concentration of the acid solution is 0.5-1 mol / L.

[0017] According to some embodiments of the present invention, the conditions for the impregnation treatment include: an impregnation liquid-to-solid ratio of 5:1-20:1 and an impregnation time of 0.5-24 h. Further, the conditions for the impregnation treatment include: an impregnation liquid-to-solid ratio of 5:1-15:1 and an impregnation time of 0.5-1.5 h.

[0018] According to some embodiments of the present invention, the impregnation process is carried out while constant temperature oscillation is performed.

[0019] According to some embodiments of the present invention, the conditions for the isothermal oscillation include: a temperature of 20-30°C and an oscillation speed of 200-300 r / min.

[0020] According to some embodiments of the present invention, the conditions for ultrasonic treatment include: ultrasonic power of 300-500W and ultrasonic treatment time of 5-60min. Further, the conditions for ultrasonic treatment include: ultrasonic power of 300-500W and ultrasonic treatment time of 10-40min. Even further, the conditions for ultrasonic treatment include: ultrasonic power of 300-500W and ultrasonic treatment time of 10-30min.

[0021] According to some embodiments of the present invention, after the solid is washed with water and dried, it is further pulverized and passed through a 100-200 mesh sieve.

[0022] A second aspect of the present invention provides an adsorbent prepared by the method described in this invention for preparing an adsorbent using vacuum pyrolysis residue from waste circuit boards.

[0023] The third aspect of this invention provides the application of the above-mentioned adsorbent in the treatment of dyeing and printing wastewater.

[0024] According to some embodiments of the present invention, the dyeing and printing wastewater contains methylene blue.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] The method provided by this invention uses waste circuit board vacuum pyrolysis residue as raw material. Since the waste circuit board vacuum pyrolysis residue is a product obtained by pyrolysis of waste circuit board resin powder, it does not affect the pyrolysis to obtain pyrolysis oil and recover organic components such as phenol. By acid impregnation and ultrasonic treatment of the waste circuit board vacuum pyrolysis residue, an adsorbent is prepared. It has the characteristics of simple and easy process, low manufacturing cost, high resource utilization rate and environmental friendliness. It can effectively solve the problems of traditional landfill disposal of vacuum pyrolysis residue and occupation of land resources.

[0027] The adsorbent prepared by this invention can be well applied to the treatment and disposal of dyeing and printing wastewater, with good application prospects. It can not only make rational use of resources and improve the economic value of waste circuit board resin powder, but also achieve the purpose of environmental protection. Detailed Implementation

[0028] The present invention will be further described in detail below through specific embodiments. Unless otherwise specified, the raw materials, reagents, or apparatus used in the embodiments can be obtained from conventional commercial sources or by existing technical methods. Unless otherwise specified, the experimental or testing methods are conventional methods in the art.

[0029] Example 1

[0030] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0031] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0032] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L nitric acid solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250 r / min, and the impregnation time is 60 min.

[0033] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0034] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0035] Example 2

[0036] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0037] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0038] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L of phosphoric acid solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250 r / min, and the impregnation time is 60 min.

[0039] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0040] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0041] Example 3

[0042] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0043] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0044] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L citric acid solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250r / min, and the impregnation time is 60min.

[0045] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0046] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0047] Example 4

[0048] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0049] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0050] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L acetic acid solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250r / min, and the impregnation time is 60min.

[0051] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0052] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0053] Example 5

[0054] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0055] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0056] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 0.5 mol / L citric acid solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250 r / min, and the impregnation time is 60 min.

[0057] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0058] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0059] Example 6

[0060] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0061] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0062] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L citric acid solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250r / min, and the impregnation time is 60min.

[0063] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 40min.

[0064] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0065] Comparative Example 1 (The difference from Example 3 is that water is used instead of acid solution)

[0066] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0067] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0068] (2) Place the adsorbent precursor obtained in step (1) into a flask, add water, and then place it in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250r / min, and the impregnation time is 60min.

[0069] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0070] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0071] Comparative Example 2 (the difference from Example 3 is that NaOH solution was used instead of acid solution)

[0072] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0073] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0074] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L NaOH solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250r / min, and the impregnation time is 60min.

[0075] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0076] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0077] Comparative Example 3 (The difference from Example 3 is that Na2CO3 solution was used instead of acid solution)

[0078] A method for preparing adsorbents using vacuum pyrolysis residue from waste circuit boards, the specific preparation process is as follows:

[0079] (1) Waste circuit board resin powder was vacuum pyrolyzed at 500℃ to obtain waste circuit board resin powder pyrolysis residue. The waste circuit board resin powder pyrolysis residue was then crushed, passed through a 200-mesh sieve, washed with water until neutral, and dried in an oven at 105℃ to obtain adsorbent precursor.

[0080] (2) The adsorbent precursor obtained in step (1) is placed in a flask, 1 mol / L Na2CO3 solution is added, and then placed in a constant temperature shaker for oscillation and impregnation treatment to obtain a mixed solution; the treatment conditions are: the impregnation liquid-solid ratio is 10:1, the oscillation temperature is 25℃, the oscillation speed is 250r / min, and the impregnation time is 60min.

[0081] (3) Place the mixture obtained in step (2) in a water bath ultrasonic instrument for ultrasonic treatment; the treatment conditions are: ultrasonic power of 400W and ultrasonic time of 10min.

[0082] (4) After the ultrasonic treatment in step (3) is completed, the mixture is filtered, the solid is collected, the solid is washed with water until neutral, dried at 105°C, ground and crushed, and passed through a 200-mesh sieve to obtain the adsorbent.

[0083] Adsorption performance test of adsorbent

[0084] The adsorbents prepared in Examples 1-6 and Comparative Examples 1-3 were weighed at 0.1 g and placed in a 250 mL flask. A 25 mL solution of methylene blue with a pH of 7 and a concentration of 150 mg / L was added. The flask was placed in a constant temperature shaker at 25 °C and 250 rpm for 20 min for adsorption. The adsorption capacity of each group of adsorbents was counted. The results are shown in Table 1.

[0085] Table 1

[0086] Group Adsorption capacity (mg / g) Example 1 9.535 Example 2 10.221 Example 3 32.264 Example 4 11.153 Example 5 30.123 Example 6 30.212 Comparative Example 1 8.538 Comparative Example 2 9.200 Comparative Example 3 8.950

[0087] The data comparison in Table 1 shows that, comparing the test results of Examples 1-6 and Comparative Examples 1-3, the adsorbent prepared by the present invention using acid solution impregnation-ultrasonic treatment exhibits a higher methylene blue adsorption value, with citric acid solution impregnation showing the best effect. Comparing Examples 3 and 5, within a certain range, increasing the concentration of citric acid solution improves the methylene blue adsorption value of the prepared adsorbent. Comparing Examples 3 and 6, extending the ultrasonic treatment time does not significantly increase the methylene blue adsorption value of the prepared adsorbent.

[0088] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A method for preparing an adsorbent using vacuum pyrolysis residue from waste circuit boards, characterized in that, Includes the following steps: Waste circuit board vacuum pyrolysis residue is crushed, sieved, washed and dried to obtain adsorbent precursor; The adsorbent precursor is mixed with an acid solution and impregnated to obtain a mixture. The mixture is subjected to ultrasonic treatment; The mixture after ultrasonic treatment is filtered, the solid is collected, and then the solid is washed with water and dried to obtain the adsorbent. The waste circuit board vacuum pyrolysis residue is obtained by vacuum pyrolysis of waste circuit board resin powder at 400-550℃. The vacuum pyrolysis residue of the waste circuit board is mainly composed of pyrolytic carbon and glass fiber. The acid solution is a citric acid solution.

2. The method for preparing adsorbent using vacuum pyrolysis residue of waste circuit boards according to claim 1, characterized in that, The sieving process involves passing the material through a 120-200 mesh sieve.

3. The method for preparing adsorbent using vacuum pyrolysis residue of waste circuit boards according to claim 1, characterized in that, The drying temperature is ≥100℃.

4. The method for preparing adsorbent using vacuum pyrolysis residue of waste circuit boards according to claim 1, characterized in that, The concentration of the acid solution is 0.1-10 mol / L.

5. The method for preparing adsorbent using vacuum pyrolysis residue of waste circuit boards according to claim 1, characterized in that, The conditions for the impregnation treatment include: an impregnation liquid-to-solid ratio of 5:1 to 20:1 and an impregnation time of 0.5 to 24 hours.

6. The method for preparing adsorbent using vacuum pyrolysis residue of waste circuit boards according to claim 1, characterized in that, The conditions for ultrasonic treatment include: ultrasonic power of 300-500W and ultrasonic treatment time of 5-60min.

7. An adsorbent, characterized in that, It is prepared by the method for preparing adsorbent using vacuum pyrolysis residue of waste circuit boards as described in any one of claims 1 to 6.

8. The application of the adsorbent according to claim 7 in the treatment of dyeing and printing wastewater.