A porous organic polymer and a preparation method and application thereof

Abstract

This invention discloses a porous organic polymer, its preparation method, and its applications, belonging to the field of polymer materials technology. The porous organic polymer, with the structure shown in formula (I) as the repeating unit, is obtained by polymerization of compound 1 and 1,3,5-tris(bromomethyl)benzene via a Menshutkin quaternization reaction. The polymer backbone simultaneously contains phthalocyanine units and cationic pyridine sites, forming a donor-acceptor structure. The phthalocyanine units act as electron donors and coordination adsorption centers to capture AuCl4. ‑ The cationic pyridine site acts as an electron acceptor and electrostatic adsorption center to anchor AuCl4. ‑ And electrons are transferred to AuCl4 through the D-A electron transport channel. ‑ This process promotes the reduction of gold to Au(0), achieving a synergistic "adsorption-reduction" recovery of gold. The equilibrium adsorption capacity of this material for gold under both dark and light conditions reaches 1273 mg·g⁻¹. ‑1 and 2262 mg·g ‑1 It has good selectivity and recycling performance, and can be used to recover gold from electronic waste leachate.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a porous organic polymer and its preparation method and application. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Gold is widely used in electronic components due to its excellent chemical stability and electrical conductivity, but its natural reserves are limited. With the surge in electronic waste, the gold content of which is far higher than that of primary ore, recovering gold from secondary resources has become an important pathway for resource recycling. Hydrometallurgy typically uses a hydrochloric acid-oxidant system to convert gold into AuCl4. - Complex anions are then enriched using an adsorbent.

[0004] Porous organic polymers (POPs) are widely used for metal ion adsorption due to their tunable structure, large specific surface area, and good chemical stability. Among them, phthalocyanine-based POPs have attracted much attention in the field of metal adsorption because of the abundant coordinated nitrogen atoms in the phthalocyanine macrocycle and excellent photoelectric properties. However, existing phthalocyanine-based POPs have limitations in their application to AuCl4. - The adsorption of AuCl4 mainly relies on single coordination or electrostatic interactions, and its adsorption capacity and rate remain quite limited. More importantly, the photogenerated electron capability of the phthalocyanine unit has not yet been effectively utilized for in-situ reduction of AuCl4. - This prevents the adsorption sites from regenerating quickly, limiting further improvements in material performance. How to simultaneously construct stable electrostatic adsorption centers and efficient electron transport pathways in phthalocyanine-based POPs to achieve synergistic effects between adsorption and reduction remains a challenging technical problem. Summary of the Invention

[0005] To overcome the above problems, the present invention provides a porous organic polymer, its preparation method and application.

[0006] To achieve the above technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a porous organic polymer having the structure shown in formula (I) as a repeating structural unit;

[0007] Equation (Ⅰ).

[0008] A second aspect of the present invention provides a method for preparing the porous organic polymer described in the first aspect, comprising the following steps: Compound 1 and 1,3,5-tris(bromomethyl)benzene were dissolved in DMF, stirred under a nitrogen atmosphere, and heated to react. The reaction mixture was poured into acetone to form a precipitate. The solid product was collected by filtration, washed, and dried to obtain a porous organic polymer. The structural formula of compound 1 is shown below: .

[0009] This invention utilizes the Menshutkin reaction to quaternize and polymerize compound 1-tetra(4-pyridyloxy)phthalocyanine (H2Pc(OPy)4) with 1,3,5-tris(bromomethyl)benzene (TBMB), thereby constructing a porous organic polymer, Pyd-Pc-POPs-Br, rich in cationic pyridine sites and possessing a donor-acceptor (DA) structure. The phthalocyanine unit acts as an electron donor and coordination adsorption center, capturing AuCl4 through coordination interactions. - The pyridine cationic site acts as both an electron acceptor and an electrostatic adsorption center, enabling it to anchor AuCl4 via electrostatic attraction. - When AuCl4 - After being adsorbed onto the material surface, the phthalocyanine units donate electrons and, with the help of the DA electron transport channels built inside the material, efficiently transfer electrons to the adsorbed AuCl4. - This process induces a reduction reaction, gradually converting Au(III) into Au(0). During the continuous reduction of Au(III), the adsorption sites are continuously released and re-engage with the next round of AuCl4 reduction. - The material captures gold through an adsorption-reduction synergistic mechanism, achieving a gold adsorption capacity far exceeding that of traditional static adsorption modes, with an equilibrium adsorption capacity reaching 1273 mg·g⁻¹. -1 Furthermore, due to the introduction of a large number of phthalocyanine light-absorbing units into the material, it possesses excellent broad-spectrum absorption capabilities. Under illumination, it can generate more photoexcited electrons, which rapidly migrate to the adsorption sites along the DA electron transport path, further accelerating the adsorption of AuCl4. - The reduction process continuously regenerates the adsorption sites, thereby further increasing the material's adsorption capacity for gold to 2262 mg·g⁻¹. -1 Furthermore, this material also exhibits rapid adsorption kinetics, high selectivity, good recycling performance, and the ability to efficiently recover gold from actual electronic waste leachate.

[0010] In one or more embodiments, the molar ratio of compound 1 to 1,3,5-tris(bromomethyl)benzene is 1:(1.0~1.5).

[0011] In one or more embodiments, the temperature of the heating reaction is 80~120℃, preferably 100℃; the time of the heating reaction is 24~72 hours, preferably 48 hours.

[0012] In one or more embodiments, the washing process involves sequentially using methanol, acetone, DMF, water, methanol, and acetone.

[0013] In one or more embodiments, the drying temperature is 60~100℃, preferably 80℃.

[0014] In one or more embodiments, the preparation method of compound 1 includes the following steps: Compound 2 was dissolved in 1-pentanol, stirred under a nitrogen atmosphere, and then 1,8-diazabicyclo[5.4.0]undec-7-ene was added. The mixture was refluxed, and after the reaction was completed, cyclohexane was added to induce precipitation. The solid product was collected by filtration, washed with hexane, and dried to obtain compound 1. Compound 2 is 4-(4-pyridinoxy)phthalonitrile, and its structural formula is shown below: .

[0015] In one or more embodiments, the molar ratio of compound 2 to 1,8-diazabicyclo[5.4.0]undec-7-ene is 1:(3-6). The reflux reaction is carried out at a temperature of 130–150°C for 12–24 hours, preferably 18 hours.

[0016] In one or more embodiments, the preparation method of compound 2 includes the following steps: 4-Nitrophthalonitrile, 4-hydroxypyridine and potassium carbonate were mixed with DMF and heated and stirred under a nitrogen atmosphere. After cooling, deionized water was added and allowed to stand to form a precipitate. The solid product was collected by centrifugation and dried to obtain compound 2. Preferably, the molar ratio of 4-nitrophthalonitrile to 4-hydroxypyridine is 1:(1.0 to 1.2). Preferably, the molar ratio of 4-nitrophthalonitrile to potassium carbonate is 1:(4-6), more preferably 1:5; Preferably, the temperature of the heating and stirring reaction is 70-90°C, more preferably 80°C; the reaction time is 2-5 hours, more preferably 3 hours.

[0017] A third aspect of the present invention provides the application of the porous organic polymer described in the first aspect or the porous organic polymer prepared by the preparation method described in the second aspect in metal recycling; wherein the metal includes gold.

[0018] The beneficial effects of this invention are as follows: (1) In this invention, the polymer backbone simultaneously contains phthalocyanine units (electron donors / coordination centers) and cationic pyridine sites (electron acceptors / electrostatic centers), forming a donor-acceptor (DA) structure. The cationic pyridine sites rapidly anchor AuCl4 through electrostatic attraction. - Phthalocyanine units capture AuCl4 through coordination. - The dual adsorption sites ensure efficient capture. After adsorption, electrons provided by the phthalocyanine unit are transferred to AuCl4 along the DA channel. - The adsorption site is then reduced to Au(0), releasing and regenerating itself to participate in the next round of adsorption. This "adsorption-reduction" cycle mechanism breaks through the limitations of static adsorption equilibrium, enabling the equilibrium adsorption capacity to reach 1273 mg·g⁻¹. -1 It is far superior to traditional adsorbents.

[0019] (2) Phthalocyanine units have broad-spectrum absorption capabilities and generate a large number of photogenerated electrons under illumination. These electrons migrate rapidly to the adsorption site along the DA pathway, significantly accelerating the adsorption of AuCl4. - The reduction of [something] promotes faster regeneration of adsorption sites. Therefore, the adsorption capacity under light conditions is further increased to 2262 mg·g. -1 This achieves photo-driven adsorption enhancement. The pyridine sites of the cationic group are associated with AuCl4. - It exhibits specific electrostatic recognition, preferentially adsorbing gold in multi-metal coexistence systems; simultaneously, the DA electron transport channel shortens the reduction reaction time, allowing adsorption to reach equilibrium in a short time. The quaternized crosslinked framework endows the material with excellent chemical stability, maintaining good performance after multiple adsorption-desorption cycles, and can efficiently recover gold from real electronic waste leachate, demonstrating potential for industrial applications. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0021] Figure 1 A schematic diagram of the synthesis of the porous organic polymer Pyd-Pc-POPs-Br; Figure 2 The characterization results of Pyd-Pc-POPs-Br in this invention are shown below, where (a) is the FT-IR spectrum, (b) is the ¹³C CP / MAS NMR spectrum, (c) is the XPS spectrum, (d) is the TGA curve, (e) is the PXRD spectrum, (f) is the pore size distribution curve, (g) is the SEM image, (h) is the TEM image, and (i) is the EDS elemental distribution map. Figure 3The adsorption performance test results of Pyd-Pc-POPs-Br of the present invention are shown below. (a) shows the adsorption capacity of Pyd-Pc-POPs-Br at different pH values, (b) shows the Zeta potential of Pyd-Pc-POPs-Br and H2Pc(OPy)4 at different pH values, (c) shows the adsorption rate of Pyd-Pc-POPs-Br under dark and light conditions, (d) shows the quasi-first-order kinetic model under dark and light conditions, (e) shows the quasi-second-order kinetic model under dark and light conditions, and (f) shows the Weber-Morris model. Figure 4 The adsorption isotherms and thermodynamic test results of Pyd-Pc-POPs-Br of this invention are shown below. Among them, (a) shows the adsorption capacity of different initial Au(III) concentrations under dark and light conditions, (b) shows the Langmuir isotherm fitting results, (c) shows the Freundlich isotherm fitting results, (d) shows the Temkin isotherm fitting results, (e) shows the comparison of the adsorption capacity of this material with other adsorbents, and (f) shows the adsorption energy at different temperatures. Figure 5 The adsorption selectivity and mechanism characterization results of Pyd-Pc-POPs-Br of the present invention are shown below. Among them, (a) is the selectivity test result, (b) is the reusability test result, (c) is the practicality test result, (d) is the XPS spectrum of Pyd-Pc-POPs-Br and Pyd-Pc-POPs-Br-Au, (e) is the PXRD spectrum of Pyd-Pc-POPs-Br and Pyd-Pc-POPs-Br-Au, (f) is the high-resolution XPS spectrum of Pyd-Pc-POPs-Br with N1s, (g) is the high-resolution XPS spectrum of Pyd-Pc-POPs-Br-Au with N1s, (h) is the EDS spectrum of Pyd-Pc-POPs-Br-Au, and (i) is the TEM image of Pyd-Pc-POPs-Br-Au. Figure 6 The results of the adsorption mechanism study of Pyd-Pc-POPs-Br in this invention are shown in (a) for the high-resolution XPS spectrum of Au4f, (b) for the HOMO-LUMO spectrum, (c) for the UV-Vis spectrum of H2Pc(OPy)4 and the UV-Vis-NIR diffuse reflectance spectrum of Pyd-Pc-POPs-Br, and (d) for the schematic diagram of the adsorption mechanism. Figure 7 The synthetic route and 1H NMR spectrum of 4-(4-pyridinoxy)-phthalonitrile (compound 2, PyOP) of this invention are shown below. Figure 8 The synthetic route for tetra(4-pyridyloxy)phthalocyanine (compound 1, H2Pc(OPy)4) of this invention is as follows; Figure 9 These are the stability test results of Pyd-Pc-POPs-Br in different solutions according to the present invention; Figure 10 FTIR spectra of the original Pyd-Pc-POPs-Br and Pyd-Pc-POPs-Br after different solution treatments; Figure 11 This is the N2 adsorption-desorption isotherm of Pyd-Pc-POPs-Br of the present invention; Figure 12 This is a TEM image of Pyd-Pc-POPs-Br from the present invention; Figure 13 The linear curve of lnkc with respect to 1 / T; Figure 14 FTIR spectra of raw and recovered Pyd-Pc-POPs-Br; Figure 15 To recover SEM images of Pyd-Pc-POPs-Br; Figure 16 The cyclic voltammetry (CV) curves of ferrocene and Pyd-Pc-POPs-Br are shown. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0025] The following examples illustrate the processes involved in the adsorption test: Pyd-Pc-POPs-Br (2 mg) was mixed with 10 mL of Au(III) solution and stirred vigorously at room temperature. The effect of pH on adsorption behavior was investigated by mixing Au(III) solution (500 ppm, pH = 1–11) with Pyd-Pc-POPs-Br and stirring at 298 K for a certain period of time. The samples were separated using a 0.45 μm filter membrane, and the Au(III) content in the samples was determined by ICP-AES. The pH was adjusted with diluted HCl and NaOH solutions.

[0026] For kinetic studies, Pyd-Pc-POPs-Br (20 mg) was mixed with Au(III) solutions of different concentrations (10 ppm), stirred at 298 K, and samples were taken at different adsorption time points. The samples were separated using a 0.45 μm filter membrane, and the Au(III) content in the samples was determined by inductively coupled plasma optical emission spectrometry (ICP-OES).

[0027] In the isothermal experiment, Pyd-Pc-POPs-Br (2 mg) was mixed with Au(III) solution (pH=4) at an initial concentration of 100~1500 ppm. After adsorption at 298 K for a certain time, the sample was separated using a 0.45 μm filter membrane, and the Au(III) content in the sample was determined by ICP-OES.

[0028] In the adsorption thermodynamic test, 2 mg of Pyd-Pc-POPs-Br was added to 10 mL of 500 ppm Au(III) solution, and stirred for a certain time at pH=4, with temperatures of 298 K, 308 K, 318 K, and 328 K. After adsorption, the sample was separated using a 0.45 μm filter membrane, and the Au(III) content in the sample was determined by ICP-OES.

[0029] The adsorption selectivity of Pyd-Pc-POPs-Br was determined by immersing 3 mg of Pyd-Pc-POPs-Br in 15 mL of a solution containing Ni(II), Co(II), Zn(II), Cu(II), Cd(II), Cr(VI), Mn(II), and Au(III). The concentration of Au(III) was set at 10 ppm, and the others at 100 ppm. After stirring the sample at 298 K for a certain period of time, it was separated using a 0.45 μm filter membrane, and the content of all metal ions in the solution was determined by ICP-OES.

[0030] In the cyclic experiment, 10 mg of Pyd-Pc-POPs-Br was mixed with 10 mL of Au(III) aqueous solution (50 ppm, pH=4) and stirred for a certain period of time. After adsorption, the solid was collected by centrifugation, eluted three times each with 10 mL of acidified thiourea solution (10% thiourea + 5% hydrochloric acid) and deionized water, and then the material was freeze-dried and added to the next adsorption cycle.

[0031] Example 1 Preparation of porous organic polymer Pyd-Pc-POPs-Br: (1) Preparation of compound 2 (4-(4-pyridinoxy)phthalonitrile, PyOP): 4-Nitrophthalonitrile (500 mg, 2.89 mmol), 4-hydroxypyridine (302 mg, 3.18 mmol), and potassium carbonate (2 g, 14.50 mmol) were mixed with N,N-dimethylformamide (DMF, 15 mL) in a 50 mL three-necked flask. The reaction mixture was heated to 80 °C and stirred for 3 h under a nitrogen atmosphere. After cooling to room temperature, deionized water (60 mL) was added, and the mixture was allowed to stand for 5 h, resulting in the formation of a white precipitate. The solid product was collected by centrifugation and dried at 80 °C to give a white solid compound 2 (294 mg, 38% yield). (The synthetic route and 1H NMR spectrum are shown in [reference needed]). Figure 7 ).

[0032] (2) Preparation of compound 1 (tetra(4-pyridyloxy)phthalocyanine, H2Pc(OPy)4): Compound 2 (200 mg, 0.23 mmol) was dissolved in 1-pentanol (7.50 mL) in a 50 mL three-necked flask and stirred for 10 min under nitrogen atmosphere. Then, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, 150 μL, 1 mmol) was added, and the mixture was refluxed at 140 °C for 18 h. After cooling to room temperature, cyclohexane (50 mL) was added to induce precipitation. The resulting solid was collected by filtration and thoroughly washed with hexane. The product was dried at 80 °C to give compound 1 as a dark green solid (173 mg, 87% yield). (See synthetic route for details.) Figure 8 ).

[0033] (3) Preparation of porous organic polymer Pyd-Pc-POPs-Br: Compound 1 (88.70 mg, 0.10 mmol) and 1,3,5-tris(bromomethyl)benzene (TBMB, 47.60 mg, 0.13 mmol) were dissolved in DMF (3 mL) and placed in a 50 mL three-necked flask. The mixture was stirred for 10 minutes under a nitrogen atmosphere, then heated at 100 °C for 48 hours. The reaction mixture was poured into acetone (100 mL), forming a black precipitate. The solid product was collected by filtration and washed successively with methanol, acetone, DMF, water, methanol, and acetone. Finally, the product was dried at 80 °C to give Pyd-Pc-POPs-Br as a blackish-green powder (47.80 mg, yield 35%). (See schematic diagram of synthesis for details.) Figure 1 ).

[0034] Characterization and testing: The Pyd-Pc-POPs-Br prepared in this embodiment was characterized as follows: The structure of Pyd-Pc-POPs-Br was characterized. FT-IR spectrum, 13C CP / MAS NMR and XPS spectra were obtained. Figure 2 The successful construction of the polymer framework was jointly verified by the TGA curves, indicating that the Menshutkin reaction quaternization polymerization of compound 1 and TBMB successfully occurred. Figure 2 d) shows that the material retains 90% of its mass at 374℃, exhibiting good thermal stability. PXRD spectrum ( Figure 2 e), the peak at 26 degrees indicates the amorphous nature of the material, proving the high degree of cross-linking between monomers. Pore size distribution curve ( Figure 2 f) and N2 adsorption-desorption isotherms ( Figure 11 This indicates that it has porous properties. SEM and TEM images ( Figure 2 g) shows its irregular blocky morphology, EDS mapping ( Figure 2 i) shows that C, N, O, and Br elements are evenly distributed. Furthermore, stability tests ( Figure 9 , Figure 10 This indicates that the material can maintain its structural integrity in various solvents such as methanol, ethanol, DMF, and acid-base aqueous solutions.

[0035] Example 2 The effect of pH on adsorption performance: Pyd-Pc-POPs-Br (2 mg) was mixed with 10 mL of Au(III) solutions (500 ppm) at different pH values ​​(pH = 1–11) and stirred vigorously at 298 K. The samples were separated using a 0.45 μm filter membrane, and the Au(III) content in the liquid was determined by ICP-AES. The results are as follows: Figure 3As shown in Figure a, the material exhibits the highest adsorption efficiency for Au(III) at pH=4; therefore, the optimal pH for subsequent experiments was set to 4. Zeta potential test results ( Figure 3 b) indicates that, due to the presence of protonated cationic pyridine sites on the framework, the material surface is positively charged at pH below 11, which facilitates interaction with the anion AuCl4. - Electrostatic attraction is generated.

[0036] Adsorption kinetics study: Pyd-Pc-POPs-Br (20 mg) was mixed with Au(III) solution (10 ppm, pH=4), stirred at 298 K, and samples were taken at different time points. The results are as follows: Figure 3 As shown in c, the adsorption rate is significantly faster under illumination than under dark conditions. The data were fitted using quasi-first-order, quasi-second-order kinetic models and the Weber-Morris model. Figure 3 The results showed that the quasi-second-order kinetic model had a higher correlation (R²>0.99), indicating that chemisorption played a dominant role in the process; under illumination, the mass transfer rate constant increased significantly due to the participation of photoexcited electrons.

[0037] Isothermal adsorption experiment: Pyd-Pc-POPs-Br (2 mg) was mixed with Au(III) solutions (pH=4) of different initial concentrations (100~1500 ppm) and adsorbed at 298 K for a certain period of time. The results are as follows. Figure 4 As shown in figure a, under illumination, the maximum adsorption capacity fitted by the Langmuir model can reach 2451 mg / g (the experimentally determined equilibrium adsorption capacity can reach 2262 mg·g). -1 This is much higher than the 1202 mg / g under dark conditions (experimental equilibrium adsorption capacity 1273 mg·g). -1 To analyze the adsorption mechanism, the adsorption isotherm data were fitted using the Langmuir, Freundlich, and Temkin isotherm models. Figure 4 (b)~(d)). The results show that Pyd-Pc-POPs-Br has a positive effect on AuCl4. - Adsorption mainly occurs through monolayer adsorption, and the maximum adsorption capacity calculated under light conditions can reach 2262 mg·g⁻¹. -1 It surpasses most reported gold adsorbents ( Figure 4 (e) Adsorption thermodynamics experiment: 2 mg of Pyd-Pc-POPs-Br was added to 10 mL of 500 ppm Au(III) solution, and tests were performed at pH 4 at 298 K, 308 K, 318 K, and 328 K. Results ( Figure 4 f、 Figure 13 The results show that the adsorption amount increases with increasing temperature. The thermodynamic parameters ΔG are negative, while ΔH and ΔS are positive, indicating that the adsorption of Au(III) by Pyd-Pc-POPs-Br is a spontaneous endothermic process.

[0038] Example 3 Adsorption selectivity study: 3 mg of Pyd-Pc-POPs-Br was immersed in 15 mL of a mixed solution containing Ni(II), Co(II), Zn(II), Cu(II), Cd(II), Cr(VI), Mn(II) (all at 100 ppm) and Au(III) (at 10 ppm) and stirred at 298 K. The results are as follows. Figure 5 As shown in figure a, Pyd-Pc-POPs-Br exhibits excellent selectivity for Au(III). This is attributed to its protonated cationic framework under acidic conditions for AuCl4. - It has specific electrostatic anchoring and coordination synergistic effect with phthalocyanine centers.

[0039] Material recycling experiment: 10 mg of Pyd-Pc-POPs-Br was mixed with 10 mL of Au(III) aqueous solution (50 ppm, pH=4) and stirred for a certain period of time. The solid was collected by centrifugation and eluted three times with 10 mL of acidified thiourea solution (10% thiourea + 5% hydrochloric acid) and deionized water, respectively. The material was then freeze-dried and fed into the next cycle. The results are as follows: Figure 5 As shown in b, the material maintains high adsorption efficiency even after multiple adsorption-desorption cycles. The recovered FTIR spectrum (…). Figure 14 ) and SEM images ( Figure 15 The material is highly similar to the original material, demonstrating its excellent structural stability and recyclability during long-term use.

[0040] Example 4 Practicality test of gold recovery from actual electronic waste leachate: To verify the industrial applicability of Pyd-Pc-POPs-Br, it was applied to the aqua regia leachate of actual electronic waste (such as used CPUs). After adjusting the pH of the leachate to 4 by alkalization, the Pyd-Pc-POPs-Br material was added for adsorption testing. The results are as follows: Figure 5As shown in c, although the leachate contains a large number of coexisting metal ions (such as Cu²⁺) + Zn² + Even with methods like Pyd-Pc-POPs-Br, gold can still be recovered efficiently and selectively, with extremely high recovery rates. This demonstrates the significant practical value of the porous organic polymer provided by this invention in the efficient recovery of gold from complex electronic waste matrices.

[0041] Example 5 Adsorption mechanism study: The material after Au(III) adsorption (Pyd-Pc-POPs-Br-Au) was characterized by XPS, PXRD, and TEM. XPS full spectrum ( Figure 5 d) and EDS spectrum ( Figure 5 h) indicates successful adsorption of gold, TEM image ( Figure 5 Uniformly dispersed gold nanoparticles were observed in the high-resolution XPS spectra of Au4f (i). Figure 6 a) contains characteristic peaks of both Au(III) and Au(0), as shown in the PXRD spectrum ( Figure 5 The presence of diffraction peaks corresponding to the Au(0) crystal plane in the N1s spectrum indicates that the adsorption process is accompanied by a reduction reaction. (High-resolution XPS spectrum of N1s) Figure 5 (f, 5g) showed a shift in the binding energies of pyridine nitrogen and phthalocyanine nitrogen after adsorption, confirming the electrostatic attraction of the cationic pyridine site and the coordination effect of the central nitrogen atom of phthalocyanine. Combined with HOMO-LUMO spectroscopy ( Figure 6 b) Ultraviolet-visible-near-infrared diffuse reflectance spectrum ( Figure 6 c) and CV curve ( Figure 16 Mechanism analysis Figure 6 d) This indicates that the donor-acceptor (DA) structure within the material constructs a highly efficient electron transport channel. The phthalocyanine unit, acting as an electron donor, generates photoexcited electrons under illumination, which rapidly migrate along the DA pathway to the adsorption site, thus adsorbing AuCl4. - It is reduced to Au(0). Because the adsorption sites are continuously released and regenerated after reduction, the material exhibits a capability far exceeding that of the traditional static adsorption mode.

[0042] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A porous organic polymer, characterized in that, Its structural repeating unit is the structure shown in equation (Ⅰ); Equation (Ⅰ).

2. The method for preparing the porous organic polymer as described in claim 1, characterized in that, Includes the following steps: Compound 1 and 1,3,5-tris(bromomethyl)benzene were dissolved in DMF, stirred under a nitrogen atmosphere, and heated to react. The reaction mixture was poured into acetone to form a precipitate. The solid product was collected by filtration, washed, and dried to obtain a porous organic polymer. The structural formula of compound 1 is shown below: 。 3. The preparation method according to claim 2, characterized in that, The molar ratio of compound 1 to 1,3,5-tris(bromomethyl)benzene is 1:(1.0~1.5).

4. The preparation method according to claim 2, characterized in that, The temperature of the heating reaction is 80~120℃, preferably 100℃; the heating reaction time is 24~72 hours, preferably 48 hours.

5. The preparation method according to claim 2, characterized in that, The washing process involves sequentially washing with methanol, acetone, DMF, water, methanol, and acetone.

6. The preparation method according to claim 2, characterized in that, The drying temperature is 60~100℃, preferably 80℃.

7. The preparation method according to claim 2, characterized in that, The preparation method of compound 1 includes the following steps: Compound 2 was dissolved in 1-pentanol, stirred under a nitrogen atmosphere, and then 1,8-diazabicyclo[5.4.0]undec-7-ene was added. The mixture was refluxed, and after the reaction was completed, cyclohexane was added to induce precipitation. The solid product was collected by filtration, washed with hexane, and dried to obtain compound 1. Compound 2 is 4-(4-pyridinoxy)phthalonitrile, and its structural formula is shown below: 。 8. The preparation method according to claim 7, characterized in that, The molar ratio of compound 2 to 1,8-diazabicyclo[5.4.0]undec-7-ene is 1:(3-6). The reflux reaction is carried out at a temperature of 130–150°C for 12–24 hours, preferably 18 hours.

9. The preparation method according to claim 7, characterized in that, The preparation method of compound 2 includes the following steps: 4-Nitrophthalonitrile, 4-hydroxypyridine and potassium carbonate were mixed with DMF and heated and stirred under a nitrogen atmosphere. After cooling, deionized water was added and allowed to stand to form a precipitate. The solid product was collected by centrifugation and dried to obtain compound 2. Preferably, the molar ratio of 4-nitrophthalonitrile to 4-hydroxypyridine is 1:(1.0 to 1.2). Preferably, the molar ratio of 4-nitrophthalonitrile to potassium carbonate is 1:(4-6), more preferably 1:5; Preferably, the temperature of the heating and stirring reaction is 70-90°C, more preferably 80°C; the reaction time is 2-5 hours, more preferably 3 hours.

10. The application of the porous organic polymer of claim 1 or the porous organic polymer prepared by any one of claims 2 to 9 in metal recycling; wherein the metal includes gold.

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