Organic porous polymer, preparation method thereof and application of organic porous polymer in precious metal recovery

Abstract

The invention belongs to the technical field of high polymer materials, and discloses an organic porous polymer, a preparation method thereof and application of the organic porous polymer in precious metal recovery. The polymer is formed by polymerizing a multi-aldehyde-group functionalized molecule A and pyrrole, and the structural formula of the multi-aldehyde-group functionalized molecule A is shown as a formula (1) and is recorded as Ax-n-y; wherein A represents a multi-aldehyde molecule, x represents the number of the multi-aldehyde molecule A, and n is 0 or a positive integer; y represents an aldehyde group substitution position including an ortho-position, a meta-position or a para-position; the polymer contains a porphyrinyl ring. Small molecules with a large conjugated system are polymerized to form the organic porous polymer containing the porphyrinyl ring, and the organic porous polymer has excellent adsorption capacity on precious metals in the electronic waste liquid by utilizing the large specific surface area, open three-dimensional pore channels and excellent stability of the organic porous polymer. Covalent bonds are adopted for assembling, and the obtained product is a pure organic polymer, does not contain metal ions and has high stability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer materials, and particularly relates to an organic porous polymer, a preparation method thereof and application of the organic porous polymer in recovery of noble metals. BACKGROUND

[0002] The popularity of electronic products brings convenience to people's life, but also breeds a large number of waste electronic products, bringing huge environmental pressure. At the same time, electronic waste contains a large amount of noble metals, for example, the grade of gold in it is much higher than that of natural ore (10-100 times), which is a "urban mine" with great economic value. Therefore, extracting noble metal ions from electronic waste is an important way of noble metal recovery.

[0003] Currently, the typical process for recovering noble metals from electronic waste includes mechanical physical pretreatment, pyrometallurgical smelting or hydrometallurgical leaching, etc. Among them, the hydrometallurgical technology is widely studied and applied because of its environmental friendliness, high metal recovery rate, and suitability for small and medium scale processing. The core of this technology is: first, using aqua regia, cyanide, thiourea or iodide as leaching agent to dissolve noble metals from crushed electronic waste raw materials to form noble metal leaching solution; then, separating and enriching the target noble metal from the complex leaching solution. In the separation and enrichment stage, using adsorbent for adsorption extraction is a common method. This method uses functional materials (such as activated carbon, ion exchange resin, modified silica gel, biomass-based adsorbent and various new types of nanocomposites) to realize the specific adsorption of noble metal ions, so as to realize the recovery of noble metals. Although the adsorption method has potential advantages such as relatively simple operation and low cost, there are still a series of technical problems to be solved in the actual application of the complex system of electronic waste noble metal recovery: First, poor adsorption selectivity: the composition of electronic waste leaching solution is extremely complex, in addition to the target noble metal ions (such as Au 3 + , Ag + , Pd 2+ ), it usually contains high concentrations of base metal ions such as copper, iron, nickel, zinc, lead and tin, as well as organic additives, impurity ions, etc. Most conventional adsorbents have limited adsorption selectivity for these metal ions, resulting in the adsorption of a large number of coexisting non-noble metal ions at the same time, which seriously pollutes the adsorption sites, reduces the purity of noble metal products, and increases the difficulty and cost of subsequent desorption and refining.

[0004] Second, the adsorption capacity and kinetic performance are insufficient: Many adsorbents exhibit good adsorption capacity in laboratory pure solutions, but in actual complex leachates, their effective adsorption capacity decreases significantly due to factors such as competitive adsorption, solution pH, ionic strength, and interference from organic matter. Simultaneously, the adsorption kinetics are slow, requiring a long time to reach adsorption equilibrium, resulting in low treatment efficiency and making it difficult to meet the throughput and efficiency requirements of industrial continuous treatment.

[0005] Third, poor stability in harsh leaching systems: To effectively dissolve precious metals, leachates are often placed in harsh chemical environments characterized by strong acids (such as aqua regia), strong oxidizing agents, or those containing specific ligands (such as cyanide or thiourea). Many adsorbents (especially organic polymers) swell, degrade, lose functional groups, or suffer structural damage in such environments, leading to a sharp decline in adsorption performance, short service life, and inability to achieve stable cyclic use. Furthermore, existing organic polymer adsorbents require metal salts in their synthesis, relying on coordination bonds to assemble the final organometallic polymer. These polymers lack stability in acidic environments, resulting in metal leaching during use and causing metal contamination.

[0006] Therefore, developing a precious metal recovery organic polymer adsorbent that can adapt to the complex chemical environment of electronic waste leachate, has high selectivity, high adsorption capacity and rapid kinetics, and excellent chemical stability is crucial for improving the overall level of electronic waste resource utilization. Summary of the Invention

[0007] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an organic porous polymer, its preparation method, and its application in precious metal recovery. The polymer, as an adsorbent, exhibits high selectivity, high adsorption capacity, fast kinetics, and good stability in the precious metal recovery process.

[0008] To solve the above-mentioned technical problems, the first aspect of the present invention provides a polymer, which is polymerized from a polyaldehyde-functionalized molecule A and pyrrole, wherein the structural formula of the polyaldehyde-functionalized molecule A is shown in formula (1) and is denoted as Ax-ny; the polymer contains a porphyrin ring; Equation (1) Where: A represents a polyaldehyde molecule, x represents the number of polyaldehyde molecule A, n is 0 or a positive integer; y represents the position of aldehyde substitution, including ortho, meta or para, denoted by o, m and p respectively.

[0009] Specifically, this invention uses polyaldehyde-functionalized small molecules A and pyrrole as raw materials to polymerize small molecules with large conjugated systems to form an organic porous polymer containing porphyrin rings. Utilizing its large specific surface area, open three-dimensional channels, and excellent stability, it exhibits superior adsorption capacity for noble metals in electronic waste liquids. Furthermore, this invention employs covalent bonding for assembly, resulting in a pure organic polymer free of metal ions. Compared to traditional organometallic polymers prepared using metal salts as raw materials and relying on coordination bonds, this invention demonstrates higher stability and eliminates the problem of metal leaching, reducing the risk of subsequent metal contamination.

[0010] In some embodiments of the present invention, the polyaldehyde molecules are numbered A1-A10, and their corresponding structural formulas are as follows:

[0011]

[0012]

[0013] Wherein: G represents an aldehyde group or an aromatic ring containing an aldehyde group.

[0014] In some embodiments of the present invention, the value of n is an integer between 0 and 10, i.e., 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

[0015] In some embodiments of the present invention, the mass ratio of the polyaldehyde-functionalized molecule A to pyrrole is (0.5-10):1. For example, it can be 1:2, 1:1, 2:1, 4:1, 6:1, 8:1 or 10:1, etc., including but not limited to the mass ratios listed above, and other unlisted mass ratios within the numerical range are also applicable.

[0016] In some embodiments of the present invention, the polymer has the structural formula shown in formula (2): Equation (2).

[0017] A second aspect of the present invention provides a method for preparing the above-mentioned polymer, comprising the following steps: The polyaldehyde-functionalized molecule A and pyrrole were added to an organic solvent, heated, and subjected to a reflux reaction; after cooling, the mixture was filtered to obtain the polymer.

[0018] Taking the polyaldehyde-functionalized molecule Ax-ny as an example, when n=0 and y takes the para-p position, the synthetic route of the polymer is as follows: .

[0019] In some embodiments of the present invention, the organic solvent is selected from at least one of propionic acid, acetic acid, xylene, and nitrobenzene.

[0020] In some embodiments of the present invention, the heating temperature is 80-200°C; for example, it can be 80°C, 100°C, 120°C, 150°C or 180°C, including but not limited to the listed values, and other unlisted temperatures within the range are also applicable.

[0021] In some embodiments of the present invention, the reflux reaction time is 3-8 hours; for example, it can be 3 hours, 4 hours, 5 hours, 6 hours or 8 hours, including but not limited to the time values ​​listed, and other unlisted times within the value range are also applicable.

[0022] A third aspect of the present invention provides an adsorbent comprising the polymer described above.

[0023] A fourth aspect of the present invention provides the application of the above-described adsorbent in the recovery of precious metals.

[0024] In some embodiments of the present invention, the precious metal includes gold, silver or palladium; preferably gold.

[0025] Compared with the prior art, the above-described technical solution of the present invention has at least the following technical effects or advantages: (1) This invention uses polyaldehyde-functionalized small molecules A and pyrrole as raw materials to polymerize small molecules with large conjugated systems to form organic porous polymers containing porphyrin rings. Utilizing their large specific surface area, open three-dimensional channels and excellent stability, they have excellent adsorption capacity for noble metals in electronic waste liquid.

[0026] (2) This invention uses covalent bonds for assembly, and the resulting product is a pure organic polymer that does not contain metal ions. Compared with traditional organometallic polymers, it has higher stability and does not have the problem of metal leaching. Attached Figure Description

[0027] Figure 1 The nitrogen adsorption diagram is shown for the pure organic polymer prepared in Example 3. Figure 2 The gold adsorption isotherm of the pure organic polymer prepared in Example 3; Figure 3 This is an electron microscope image of the pure organic polymer prepared in Example 3 after gold adsorption. Figure 4 The selective absorption diagram of gold by the pure organic polymer prepared in Example 3 is shown. Figure 5 This is a cyclic adsorption diagram of gold on the pure organic polymer prepared in Example 3. Detailed Implementation

[0028] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the invention. Furthermore, all raw materials mentioned below, unless otherwise specified, are commercially available products; all process steps or preparation methods not mentioned in detail are process steps or preparation methods known to those skilled in the art.

[0029] Example 1 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 8.69 g of polyaldehyde-functionalized molecule A (structural formula A1-1-p) and 4.02 g of pyrrole, add them to 200 g of propionic acid, heat to 150 °C and stir, and reflux for 5 hours.

[0030] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A1-1-p.

[0031] Example 2 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 7.30g of polyaldehyde-functionalized molecule A (structural formula A6-0-p) and 5.36g of pyrrole, add them to 250g of propionic acid, heat to 150℃ and stir, and reflux for 3 hours.

[0032] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A6-0-p.

[0033] Example 3 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 13.84 g of polyaldehyde-functionalized molecule A (structural formula A7-1-p) and 5.36 g of pyrrole, add them to 250 g of propionic acid, heat to 150 °C and stir, and reflux for 6 hours.

[0034] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A7-1-p.

[0035] Example 4 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 8.10 g of polyaldehyde-functionalized molecule A (structural formula A2-2-p) and 5.36 g of pyrrole, add them to 250 g of propionic acid, heat to 150 °C and stir, and reflux for 4 hours.

[0036] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A2-2-p.

[0037] Example 5 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 6.85g of polyaldehyde-functionalized molecule A (structural formula A3-1-o) and 5.36g of pyrrole, add them to 250g of propionic acid, heat to 150℃ and stir, and reflux for 6 hours.

[0038] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A3-1-o.

[0039] Example 6 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 5.35g of polyaldehyde-functionalized molecule A (structural formula A5-0-p) and 5.36g of pyrrole, add them to 250g of propionic acid, heat to 150℃ and stir, and reflux for 6 hours.

[0040] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A5-0-p.

[0041] Example 7 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 9.53g of polyaldehyde-functionalized molecule A (structural formula A8-3-p) and 5.36g of pyrrole, add them to 250g of propionic acid, heat to 150℃ and stir, and reflux for 6 hours.

[0042] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A8-3-p.

[0043] Example 8 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 21.42 g of polyaldehyde-functionalized molecule A (structural formula A9-3-m) and 5.36 g of pyrrole, add them to 250 g of propionic acid, heat to 150 °C and stir, and reflux for 6 hours.

[0044] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A9-3-m.

[0045] Example 9 A method for preparing a pure organic polymer includes the following steps: (1) Weigh 21.42 g of polyaldehyde-functionalized molecule A (structural formula A10-2-p) and 5.36 g of pyrrole, add them to 250 g of propionic acid, heat to 150 °C and stir, and reflux for 6 hours.

[0046] (2) After the reaction is complete, cool to room temperature and filter out the insoluble matter. Then wash thoroughly with tetrahydrofuran and methanol, and dry under vacuum to obtain the pure organic polymer of this example, denoted as P-A10-2-p.

[0047] Comparative Example 1 A method for preparing a metal-organic polymer, the method referring to Example 1 of Chinese Invention Patent (Publication No. CN116020418A), includes the following steps: (1) Weigh 200 mg of 1,3,5-tris(4-carboxyphenyl)benzene and 162 mg of zirconium chloride into a 100 mL polytetrafluoroethylene reactor, add 80 mL of N,N-dimethylformamide, stir with a magnetic rotor for 15 min, and then add 16 mL of formic acid and 1 mL of water. (2) Continue stirring the obtained solid-liquid mixture for 15 min, then place it in an ultrasonic instrument and sonicate it for 10 min at a power of 180W. Heat it to 120℃ and react for 48 h to obtain the metal-organic layer precursor mixture. (3) The obtained metal-organic layer mixture was centrifuged at 8000 rpm for 10 min, the supernatant was removed and the precipitate was collected; then the precipitate was washed with N,N-dimethylformamide, and centrifuged again for 10 min after washing, and the supernatant was removed. This process was repeated 3 times; then the precipitate was washed with methanol, and centrifuged again for 10 min after washing, and the supernatant was removed. This process was repeated 3 times; finally, the centrifuged precipitate was placed in a drying oven and dried at 100℃ for 24 hours to obtain the metal-organic layer precursor powder. (4) Weigh 200 mg of the obtained metal-organic layer precursor powder into a 50 mL polytetrafluoroethylene reactor, add 40 mL of N,N-dimethylformamide, add a magnetic rotor and stir for 15 min, then add 174 mg of racemic tetra(4-carboxyphenyl)porphyrin and continue stirring for 10 min. (5) The obtained solid-liquid mixture was placed in an ultrasonic instrument and sonicated at 240W for 10 min, and then heated to 100℃ for 12 hours to obtain a modified metal-organic layer mixture. (6) Centrifuge the obtained modified polymer mixture at 6000 rpm for 5 min, remove the supernatant and collect the precipitate; then wash the precipitate with N,N-dimethylformamide, centrifuge again for 5 min after washing, remove the supernatant, and repeat this process 3 times; then wash the precipitate with acetone, centrifuge again for 5 min after washing, remove the supernatant, and repeat this process 3 times; finally, place the centrifuged precipitate in a drying oven and dry it at 80℃ for 12 hours to obtain the modified organometallic adsorbent, which is the organometallic polymer of this comparative example.

[0048] Comparative Example 2 A method for preparing a pure organic polymer, referring to existing literature (Angew. Chem. Int. Ed. 2025, 64, e202414943), includes the following steps: 2,6-Dialdehyde pyridine (0.06 mmol, 8.1 mg) and tetraaminophenylporphyrin (0.03 mmol, 20.3 mg) were dispersed in a mixed solution of 1,4-dioxane (1.0 mL) and glacial acetic acid (6 mol / L, 0.1 mL) in a 10 mL heat-resistant glass tube. After degassing through three freeze-evacuation-thawing cycles, the tube was flame-sealed and reacted at 120 °C for 3 days. The precipitate was collected by centrifugation and washed three times with THF and twice with acetone to obtain the pure organic polymer of this comparative example.

[0049] Performance testing 1. Adsorption Experimental procedure: 100 mg of the pure organic polymer P-A7-1-p sample prepared in Example 3 was loaded into an adsorption test tube and heated under vacuum at 120°C for 8 hours. Nitrogen adsorption was then performed at 77 K. The results are as follows: Figure 1 As shown in the figure, the horizontal axis represents relative pressure, and the vertical axis represents the amount of adsorption.

[0050] Depend on Figure 1 It can be seen that the sample has a diameter as high as 734 m. 2 It has a specific surface area of ​​ / g and a uniform pore size of 1.9nm.

[0051] 2. Gold adsorption isotherm Experimental procedure: 10 mg of the pure organic polymer P-A7-1-p prepared in Example 3, the organometallic polymers prepared in Comparative Examples 1-2, and the pure organic polymer samples were dispersed into 100 mL of gold ion solutions of different concentrations, respectively. After stirring for 2 hours to reach adsorption equilibrium, the concentration of residual gold in the solution was determined by ICP. The results are shown in Table 1. Table 1:

[0052] As shown in Table 1, the adsorption capacity of the pure organic polymer P-A7-1-p sample prepared in Example 3 of the present invention is much higher than that of the organometallic polymer prepared in Comparative Example 1 and the pure organic polymer prepared in Comparative Example 2, which has different raw materials and preparation process than the present invention.

[0053] In addition, the synthesis method of Comparative Example 1 is rather complicated, and the synthesis of Comparative Example 2 involves complex deoxygenation steps, and the yield of each synthesis is only in the milligram range, which is not suitable for industrial production.

[0054] Figure 2 The gold adsorption isotherm of the pure organic polymer P-A7-1-p sample prepared in Example 3 is obtained from... Figure 2 It can be seen that the sample exhibits excellent adsorption performance in gold ion solutions ranging from 100 to 5000 ppm. The adsorption removal efficiency of gold exceeds 90% in the concentration range of less than 2000 ppm, and even under high concentration conditions of 5000 ppm, the removal efficiency reaches 63%, with an adsorption capacity of 33 g / g.

[0055] 3. Microstructure Experimental procedure: The pure organic polymer P-A7-1-p sample prepared in Example 3 was loaded onto carbon cloth, and its morphology was observed using a scanning electron microscope. The results are as follows: Figure 3 As shown.

[0056] Depend on Figure 3 It can be seen that the surface of the sample with adsorbed gold shows a large number of gold nanoparticles attached to its surface.

[0057] 4. Selectivity of gold adsorption Experimental Procedure: The pure organic polymer P-A7-1-p sample prepared in Example 3 was dispersed in a mixed solution containing trivalent gold, trivalent iron, divalent nickel, divalent copper, and divalent zinc (each ion concentration was 200 ppm). After stirring at room temperature for 2 hours, the concentration of each ion was determined by ICP-MS. The results are as follows: Figure 4 As shown.

[0058] Depend on Figure 4 It can be seen that the sample exhibits high selectivity for gold in a complex solution (200 ppm) containing other ions of equal concentration, including ferric iron, nickel, copper, and zinc, with a gold removal efficiency of 99.8% and the removal efficiency of other ions less than 4%.

[0059] 5. Recyclability of gold adsorption Experimental Procedure: After gold adsorption, the pure organic polymer P-A7-1-p sample prepared in Example 3 was filtered and separated. Then, it was immersed in a thiourea aqueous solution for 12 hours for desorption. The desorbed sample was directly used in the next adsorption cycle. The results are as follows: Figure 5 As shown in the figure, the horizontal axis "Cycle number" represents the number of cycles, and the vertical axis "Removalefficiency" represents the removal efficiency.

[0060] Depend on Figure 5 It can be seen that the sample exhibits good stability and cyclicability in gold adsorption, with no decay in gold adsorption performance over five consecutive cycles, demonstrating promising application prospects.

[0061] The properties of the pure organic polymer samples prepared in Examples 1-2 and Examples 4-9 are comparable to those of the pure organic polymer P-A7-1-p sample prepared in Example 3, and will not be repeated here.

[0062] For those skilled in the art, several simple deductions or substitutions can be made without departing from the inventive concept, without requiring creative effort. Therefore, any simple improvements made to this invention by those skilled in the art based on the disclosure of this invention should be within the scope of protection of this invention. The above embodiments are preferred embodiments of this invention, and all processes similar to this invention and equivalent changes should fall within the scope of protection of this invention.

Claims

1. A polymer, characterized in that, The polymer is formed by polymerizing a polyaldehyde-functionalized molecule A and pyrrole. The structural formula of the polyaldehyde-functionalized molecule A is shown in formula (1) and is denoted as Ax-ny. The polymer contains a porphyrin ring. Equation (1) Where: A represents a polyaldehyde molecule, x represents the number of polyaldehyde molecule A, n is 0 or a positive integer; y represents the position of aldehyde substitution, including ortho, meta or para.

2. The polymer according to claim 1, characterized in that, The polyaldehyde molecules are numbered A1-A10, and their corresponding structural formulas are as follows: Wherein: G represents an aldehyde group or an aromatic ring containing an aldehyde group.

3. The polymer according to claim 1, characterized in that, The value of n is an integer between 0 and 10.

4. The polymer according to claim 1, characterized in that, The mass ratio of the polyaldehyde-functionalized molecule A to pyrrole is (0.5-10):

1.

5. The polymer according to any one of claims 1-4, characterized in that, The structural formula of the polymer is shown in formula (2): Equation (2).

6. A method for preparing the polymer according to any one of claims 1-5, characterized in that, Includes the following steps: The polyaldehyde-functionalized molecule A and pyrrole were added to an organic solvent, heated, and subjected to a reflux reaction; after cooling, the mixture was filtered to obtain the polymer.

7. The method for preparing the polymer according to claim 6, characterized in that, The organic solvent is selected from at least one of propionic acid, acetic acid, xylene, and nitrobenzene.

8. The method for preparing the polymer according to claim 6, characterized in that, The heating temperature is 80-200℃; and / or the reflux reaction time is 3-8 hours.

9. An adsorbent, characterized in that, The adsorbent comprises the polymer according to any one of claims 1-5.

10. The application of the adsorbent according to claim 9 in precious metal recycling.

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