Preparation method of PAF-polymer adsorbent material and application thereof

Abstract

A method for preparing a PAF-polymer adsorbent material and its application includes the following steps: 1) Introducing polymer monomers: Activating PAF, dispersing it in a polymer monomer solution, reacting with aeration and stirring in a flask, and washing the resulting powder; 2) Monomer polymerization: Direct in-situ oxidative polymerization of polymer monomers within the pores of PAF; Inserting polymers into the pores of the material achieves high polymer loading and high dispersibility. This composite material can be used to selectively adsorb noble metal ions in complex liquid environments, thereby recovering noble metals. Furthermore, under ultraviolet light irradiation, the gold adsorbed by this composite material can desorb into the solution.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials technology, and in particular to a method for preparing PAF-polymer adsorption materials and their applications. Background Technology

[0002] Precious metals such as gold, silver, and platinum are widely used in various industries and possess irreplaceable value. Catalysts composed of precious metals have been widely used in aerospace, petrochemicals, electronics, military industry, and biomedicine, contributing to energy conservation and environmental protection. However, the widespread use of precious metals has also strained their already limited resources. Currently, the precious metal content in waste electronic devices, automotive exhaust purifiers, and industrial waste catalysts far exceeds that in natural minerals, making precious metal-containing waste a valuable "urban mineral." Adsorption technology, characterized by its simple operation, high selectivity, environmental friendliness, and high economic benefits, is a very promising method for recovering gold from electronic waste leachate.

[0003] Currently, precious metal adsorbent materials have attracted considerable attention; however, few materials can rapidly and selectively extract precious metal ions from real, complex liquid environments. This has prompted us to develop a new, highly efficient adsorbent material for the recovery of precious metals from complex liquid environments. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned problems in the prior art and to provide a method for preparing PAF-polymer adsorbent materials and their applications.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing a PAF-polymer adsorbent material includes the following steps:

[0007] Introducing polymer monomers: PAF is dried under vacuum at a certain temperature, activated, cooled to room temperature, dispersed in a methanol solution containing polymer monomers, and then the mixture is placed in a flask and stirred under a certain temperature. The resulting powder is then washed.

[0008] The polymers are polymers with different polymerization mechanisms.

[0009] The mass ratio of PAF to polymer monomer is 0.01:1 to 1:1.

[0010] The concentration of the polymer monomer is 0.01–2.0 M.

[0011] The specified temperature is 80–200°C, and the heating temperature is 0–40°C.

[0012] The stirring reaction time is 1 to 30 hours.

[0013] The PAF-polymer adsorbent material prepared by the method of the present invention can be used to adsorb and recover noble metal ions in solution.

[0014] In applications, the noble metal ions include Au.

[0015] In application, the initial concentration of the noble metal ions is between 0.9 ppm and 3000 ppm, and the pH range of the recovered solution is between 1 and 8.

[0016] In application, the adsorption process takes 1 minute to 24 hours.

[0017] In applications, the material can be desorbed by ultraviolet light after adsorbing gold.

[0018] In application, the solution is a chloroauric acid solution or a real leachate.

[0019] Compared with the prior art, the beneficial effects achieved by the technical solution of this invention are:

[0020] This invention synthesizes a composite material of a porous aromatic framework (PAF) and polydopamine (PDA). This material achieves both the maintenance of the external porosity of the PAF and the high dispersion and high loading of the polymer within the pores. Using this material, gold ions in complex liquid environments can be treated, and noble metal ions can be recovered through redox adsorption.

[0021] The adsorbent material prepared by this invention has excellent adsorption performance in complex liquid environments (leaching solutions of waste electronic components), can achieve selective and rapid adsorption of noble metal ions, and is applicable at different pH levels, and has the ability to be recycled and regenerated. Attached Figure Description

[0022] Figure 1 The nitrogen adsorption-desorption curve of PAF-147-PDA is shown.

[0023] Figure 2 XPS spectrum of PAF-147-PDA.

[0024] Figure 3 SEM images and EDS analysis of PAF-147-PDA.

[0025] Figure 4 The isothermal adsorption curves for PAF-147-PDA are shown.

[0026] Figure 5 Adsorption kinetics of PAF-147-PDA were tested.

[0027] Figure 6 Adsorption diagram of PAF-147-PDA at different pH values

[0028] Figure 7 The results are from the selective test of PAF-147-PDA. Detailed Implementation

[0029] To make the technical problems, technical solutions and beneficial effects of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] Example 1

[0031] In this embodiment, a porous aromatic framework (PAF-147) material was used as a template. At room temperature, methanol was used as a solvent and air was used as an oxidant to introduce a polymer (polydopamine, PDA) for compounding. The amount of polymer added was 92 mg. Then, gold ions were recovered in gold-containing wastewater.

[0032] 1. PAF-147: Because the catalyst bis(1,5-cyclooctadiene)nickel(0) is sensitive to air and water, the reaction is carried out in an anhydrous and oxygen-free glove box. Take a 50mL flask and add 0.048g 1,4-dibromobenzene, 0.064g 4,4-dibromobiphenyl, 0.065g 1,3,5-tribromobenzene, 0.111g 1,3,5-tris(4-bromophenyl)benzene, 0.130g tetrabromotetraphenylmethane, and 20mL ultra-dry DMF, and dissolve the starting materials completely. Separately, 1 g of bis(1,5-cyclodiene)nickel(0)(Ni(COD)2) and 0.584 g of 2,2-bipyridine were added to a 150 mL round-bottom flask, followed by 60 mL of ultra-dry DMF for uniform dispersion. Then, 0.5 mL of 1,5-cyclodiene was added, resulting in a dark purple suspension. The round-bottom flask was placed in an 80 °C magnetic stirrer and stirred for 1 h. Finally, the fully dissolved raw materials were added, and the reaction was carried out at 80 °C for 48 h. After the reaction was allowed to cool naturally to room temperature, 30 mL of concentrated hydrochloric acid was added to quench the unreacted catalyst. The suspension was then filtered, and the grayish-white solid was collected. It was washed with deionized water and then extracted with tetrahydrofuran solution at 90 °C using a Soxhlet extract for 48 h. The solid was then dried under vacuum at 80 °C overnight to obtain a white powder, PAF-147.

[0033] 2. Preparation of free dopamine: In a glove box, 1 g of dopamine hydrochloride and 25 mL of anhydrous methanol were placed in a Shrek flask and stirred until homogeneous. Then, 0.284 g of sodium methoxide was slowly added to the mixture. After reacting at room temperature for 16 h, the free dopamine base was extracted under vacuum. A white powder of dopamine was obtained, which was dried and stored under vacuum for further use.

[0034] 3. Preparation of PAF-147-PDA: 25 mg of PAF-147 was placed in a 50 mL round-bottom flask and activated for 12 h under dynamic vacuum at 150 °C using an oil pump. After activation, the mixture was cooled to room temperature. 92 mg of dopamine and 20 mL of anhydrous methanol were added to the round-bottom flask, and the mixture was ultrasonically cleaned until the raw materials were evenly dispersed. The mixture was then stirred at 500 rpm at room temperature for 24 h. The resulting dark gray powder was washed with methanol until the washing solution was clear and transparent, and then dried overnight under vacuum at 70 °C to obtain dark gray powder PAF-147-PDA.

[0035] The attached diagram shows the nitrogen adsorption-desorption process of the composite material. Figure 1 As shown, the polymer was successfully introduced into the pores of PAF-147. The XPS spectra, SEM images, and EDS analyses of the composite material are as follows: Figure 2 , 3 As shown, the uniform distribution of nitrogen-containing functional groups proves that the polymer insertion was successful.

[0036] 5 mg of the composite material was dispersed in 10 mL of gold chloride aqueous solution with initial concentrations of 480, 770, 960, 1440, 1920, and 2880 ppm (pH adjusted between 2 and 8; the higher the gold chloride ion concentration, the lower the pH). The solution was soaked at 25°C for 24 h, and the isothermal adsorption curves were obtained by ICP-OES as shown below. Figure 4 As shown (Ce is the solution concentration at adsorption equilibrium, ppm; Qe is the adsorption capacity at adsorption equilibrium, mg / g), the maximum adsorption capacity can reach 1700 mg / g. 5 mg of the composite material was used to treat 10 mL of a 10 ppm aqueous solution of gold chloride, such as... Figure 5 As shown, 99% of (AuCl4) can be removed within 2 minutes. - The presence of ions indicates that this material can rapidly recover gold from solution. 5 mg of the composite material was used to treat solutions with pH values ​​ranging from 0 to 11, at volumes of 10 mL, and concentrations of 10 ppm (AuCl4). - In solutions, such as Figure 6 As shown, the composite material exhibits good adsorption effects within a pH range of 0–11, with removal rates exceeding 80%, and removal rates exceeding 95% within a pH range of 0–10. 5 mg of the composite material was used to treat 10 mL of solution containing 100 ppm Na. + Mg 2+ Ca 2+ K + Ni 2+ Zn 2+ Cu 2 + And 10 ppm (AuCl4) - In solutions, such as Figure 7 As shown (left column before adsorption, right column after adsorption), 99% (AuCl4)- It can be adsorbed, while the adsorption of other metal ions is negligible, demonstrating the material's good selectivity. Due to the redox adsorption of the polymer, the composite material can adsorb (AuCl4) in solution. - Adsorbed and partially reduced to gold nanoparticles, which are then anchored on the composite material.

[0037] Example 2

[0038] In this embodiment, a porous aromatic framework (PAF-147) material was used as a template. At room temperature, methanol was used as a solvent and air was used as an oxidant to introduce a polymer (polydopamine, PDA) for compounding. The amount of polymer added was 46 mg. Then, gold ions were recovered in gold-containing wastewater.

[0039] PAF-147 and free dopamine were synthesized using the same method as in Example 1.

[0040] Preparation of PAF-147-PDA: 25 mg of PAF-147 was placed in a 50 mL round-bottom flask and activated for 12 h under dynamic vacuum at 150 °C using an oil pump. After activation, the mixture was cooled to room temperature. 46 mg of dopamine and 20 mL of anhydrous methanol were added to the round-bottom flask, and the mixture was ultrasonically cleaned until the raw materials were uniformly dispersed. The mixture was then stirred at 500 rpm at room temperature for 24 h. The resulting dark gray powder was washed with methanol until the washing solution was clear and transparent, and then dried overnight under vacuum at 70 °C to obtain dark gray powder PAF-147-PDA.

[0041] 5 mg of the composite material was dispersed in 10 mL of an aqueous solution of gold chloride with an initial concentration of 1920 ppm (pH adjusted between 2 and 8, with a lower pH as the gold chloride ion concentration increases). The solution was soaked at 25 °C for 24 h. The concentration of the remaining liquid was measured by ICP-OES, and the adsorption capacity was calculated to be 1440 mg / g.

[0042] Example 3

[0043] In this embodiment, a porous aromatic framework (PAF-147) material was used as a template. At room temperature, methanol was used as a solvent and air was used as an oxidant to introduce a polymer (polydopamine, PDA) for compounding. The amount of polymer added was 138 mg. Then, gold ions were recovered in gold-containing wastewater.

[0044] PAF-147 and free dopamine were synthesized using the same method as in Example 1.

[0045] Preparation of PAF-147-PDA: 25 mg of PAF-147 was placed in a 50 mL round-bottom flask and activated for 12 h under dynamic vacuum at 150 °C using an oil pump. After activation, the mixture was cooled to room temperature. 138 mg of dopamine and 20 mL of anhydrous methanol were added to the round-bottom flask, and the mixture was ultrasonically cleaned until the raw materials were uniformly dispersed. Then, the mixture was stirred at 500 rpm at room temperature for 24 h. The resulting dark gray powder was washed with methanol until the washing solution was clear and transparent, and then dried overnight under vacuum at 70 °C to obtain dark gray powder PAF-147-PDA.

[0046] 5 mg of the composite material was dispersed in 10 mL of an aqueous solution of gold chloride with an initial concentration of 1920 ppm (pH adjusted between 2 and 8, with a lower pH as the gold chloride ion concentration increases). The solution was soaked at 25 °C for 24 h. The concentration of the remaining liquid was measured by ICP-OES, and the adsorption capacity was calculated to be 1580 mg / g.

[0047] Example 4

[0048] In this embodiment, a porous aromatic framework (PAF-147) material was used as a template. At room temperature, methanol was used as a solvent and air was used as an oxidant to introduce a polymer (polydopamine, PDA) for compounding. The amount of polymer added was 184 mg. Then, gold ions were recovered in gold-containing wastewater.

[0049] PAF-147 and free dopamine were synthesized using the same method as in Example 1.

[0050] Preparation of PAF-147-PDA: 25 mg of PAF-147 was placed in a 50 mL round-bottom flask and activated for 12 h under dynamic vacuum at 150 °C using an oil pump. After activation, the mixture was cooled to room temperature. 184 mg of dopamine and 20 mL of anhydrous methanol were added to the round-bottom flask, and the mixture was ultrasonically cleaned until the raw materials were uniformly dispersed. Then, the mixture was stirred at 500 rpm at room temperature for 24 h. The resulting dark gray powder was washed with methanol until the washing solution was clear and transparent, and then dried overnight under vacuum at 70 °C to obtain dark gray powder PAF-147-PDA.

[0051] 5 mg of the composite material was dispersed in 10 mL of an aqueous solution of gold chloride with an initial concentration of 1920 ppm (pH adjusted between 2 and 8, with a lower pH as the gold chloride ion concentration increases). The solution was soaked at 25 °C for 24 h. The concentration of the remaining liquid was measured by ICP-OES, and the adsorption capacity was calculated to be 1480 mg / g.

Claims

1. A method for preparing a porous aromatic framework-polydopamine adsorbent material, characterized in that... The process includes the following steps: drying the porous aromatic skeleton under vacuum conditions at a certain temperature, activating it, cooling it to room temperature, dispersing it in a methanol solution containing polymer monomers, stirring the mixture to react, and washing the resulting powder with methanol and then vacuum drying it after the reaction is complete; the polymer monomer is dopamine.

2. The preparation method of a porous aromatic framework-polydopamine adsorbent material as described in claim 1, characterized in that: The mass ratio of the porous aromatic skeleton to the polymer monomer is 0.01:1 to 1:

1.

3. The preparation method of a porous aromatic framework-polydopamine adsorbent material as described in claim 1, characterized in that: The concentration of the polymer monomer is 0.01–2.0 M.

4. The preparation method of a porous aromatic framework-polydopamine adsorbent material as described in claim 1, characterized in that: The specified temperature is 80–200℃.

5. The preparation method of a porous aromatic framework-polydopamine adsorbent material as described in claim 1, characterized in that: The stirring reaction time is 1 to 30 hours.

6. The application of the porous aromatic framework-polydopamine adsorbent material prepared by the preparation method according to any one of claims 1 to 5, characterized in that: Used for adsorbing and recovering precious metal ions from solutions.

7. The application as described in claim 6, characterized in that: The noble metal ions include Au.

8. The application as described in claim 6, characterized in that: The initial concentration of the noble metal ions is 0.9 ppm to 3000 ppm.

9. The application as described in claim 6, characterized in that: The pH of the recovered solution is 1 to 8.

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